Actual source code: matrix.c

  1: /*
  2:    This is where the abstract matrix operations are defined
  3:    Portions of this code are under:
  4:    Copyright (c) 2022 Advanced Micro Devices, Inc. All rights reserved.
  5: */

  7: #include <petsc/private/matimpl.h>
  8: #include <petsc/private/isimpl.h>
  9: #include <petsc/private/vecimpl.h>
 10: #include <petscsf.h>

 12: /* Logging support */
 13: PetscClassId MAT_CLASSID;
 14: PetscClassId MAT_COLORING_CLASSID;
 15: PetscClassId MAT_FDCOLORING_CLASSID;
 16: PetscClassId MAT_TRANSPOSECOLORING_CLASSID;

 18: PetscLogEvent MAT_Mult, MAT_MultAdd, MAT_MultTranspose;
 19: PetscLogEvent MAT_ADot, MAT_ANorm;
 20: PetscLogEvent MAT_MultTransposeAdd, MAT_Solve, MAT_Solves, MAT_SolveAdd, MAT_SolveTranspose, MAT_MatSolve, MAT_MatTrSolve;
 21: PetscLogEvent MAT_SolveTransposeAdd, MAT_SOR, MAT_ForwardSolve, MAT_BackwardSolve, MAT_LUFactor, MAT_LUFactorSymbolic;
 22: PetscLogEvent MAT_LUFactorNumeric, MAT_CholeskyFactor, MAT_CholeskyFactorSymbolic, MAT_CholeskyFactorNumeric, MAT_ILUFactor;
 23: PetscLogEvent MAT_ILUFactorSymbolic, MAT_ICCFactorSymbolic, MAT_Copy, MAT_Convert, MAT_Scale, MAT_AssemblyBegin;
 24: PetscLogEvent MAT_QRFactorNumeric, MAT_QRFactorSymbolic, MAT_QRFactor;
 25: PetscLogEvent MAT_AssemblyEnd, MAT_SetValues, MAT_GetValues, MAT_GetRow, MAT_GetRowIJ, MAT_CreateSubMats, MAT_GetOrdering, MAT_RedundantMat, MAT_GetSeqNonzeroStructure;
 26: PetscLogEvent MAT_IncreaseOverlap, MAT_Partitioning, MAT_PartitioningND, MAT_Coarsen, MAT_ZeroEntries, MAT_Load, MAT_View, MAT_AXPY, MAT_FDColoringCreate;
 27: PetscLogEvent MAT_FDColoringSetUp, MAT_FDColoringApply, MAT_Transpose, MAT_FDColoringFunction, MAT_CreateSubMat;
 28: PetscLogEvent MAT_TransposeColoringCreate;
 29: PetscLogEvent MAT_MatMult, MAT_MatMultSymbolic, MAT_MatMultNumeric;
 30: PetscLogEvent MAT_PtAP, MAT_PtAPSymbolic, MAT_PtAPNumeric, MAT_RARt, MAT_RARtSymbolic, MAT_RARtNumeric;
 31: PetscLogEvent MAT_MatTransposeMult, MAT_MatTransposeMultSymbolic, MAT_MatTransposeMultNumeric;
 32: PetscLogEvent MAT_TransposeMatMult, MAT_TransposeMatMultSymbolic, MAT_TransposeMatMultNumeric;
 33: PetscLogEvent MAT_MatMatMult, MAT_MatMatMultSymbolic, MAT_MatMatMultNumeric;
 34: PetscLogEvent MAT_MultHermitianTranspose, MAT_MultHermitianTransposeAdd;
 35: PetscLogEvent MAT_Getsymtransreduced, MAT_GetBrowsOfAcols;
 36: PetscLogEvent MAT_GetBrowsOfAocols, MAT_Getlocalmat, MAT_Getlocalmatcondensed, MAT_Seqstompi, MAT_Seqstompinum, MAT_Seqstompisym;
 37: PetscLogEvent MAT_GetMultiProcBlock;
 38: PetscLogEvent MAT_CUSPARSECopyToGPU, MAT_CUSPARSECopyFromGPU, MAT_CUSPARSEGenerateTranspose, MAT_CUSPARSESolveAnalysis;
 39: PetscLogEvent MAT_HIPSPARSECopyToGPU, MAT_HIPSPARSECopyFromGPU, MAT_HIPSPARSEGenerateTranspose, MAT_HIPSPARSESolveAnalysis;
 40: PetscLogEvent MAT_PreallCOO, MAT_SetVCOO;
 41: PetscLogEvent MAT_CreateGraph;
 42: PetscLogEvent MAT_SetValuesBatch;
 43: PetscLogEvent MAT_ViennaCLCopyToGPU;
 44: PetscLogEvent MAT_CUDACopyToGPU, MAT_HIPCopyToGPU;
 45: PetscLogEvent MAT_DenseCopyToGPU, MAT_DenseCopyFromGPU;
 46: PetscLogEvent MAT_Merge, MAT_Residual, MAT_SetRandom;
 47: PetscLogEvent MAT_FactorFactS, MAT_FactorInvS;
 48: PetscLogEvent MATCOLORING_Apply, MATCOLORING_Comm, MATCOLORING_Local, MATCOLORING_ISCreate, MATCOLORING_SetUp, MATCOLORING_Weights;
 49: PetscLogEvent MAT_H2Opus_Build, MAT_H2Opus_Compress, MAT_H2Opus_Orthog, MAT_H2Opus_LR;

 51: const char *const MatFactorTypes[] = {"NONE", "LU", "CHOLESKY", "ILU", "ICC", "ILUDT", "QR", "MatFactorType", "MAT_FACTOR_", NULL};

 53: /*@
 54:   MatSetRandom - Sets all components of a matrix to random numbers.

 56:   Logically Collective

 58:   Input Parameters:
 59: + x    - the matrix
 60: - rctx - the `PetscRandom` object, formed by `PetscRandomCreate()`, or `NULL` and
 61:           it will create one internally.

 63:   Level: intermediate

 65:   Notes:
 66:   For sparse matrices that have been preallocated but not been assembled, it randomly selects appropriate locations,

 68:   for sparse matrices that already have nonzero locations, it fills the locations with random numbers.

 70:   It generates an error if used on unassembled sparse matrices that have not been preallocated.

 72:   If values have been inserted with `MatSetValues()`, call `MatAssemblyBegin()` and `MatAssemblyEnd()` before calling this routine.
 73:   The matrix is assembled on return.

 75:   Example Usage:
 76: .vb
 77:      PetscRandomCreate(PETSC_COMM_WORLD, &rctx);
 78:      MatSetRandom(x, rctx);
 79:      PetscRandomDestroy(&rctx);
 80: .ve

 82:   Developer Notes:
 83:   Implementations must leave the matrix assembled with increased object state, assembling it themselves when it is not already the case.
 84:   Implementations that insert only local entries can temporarily set `MAT_NO_OFF_PROC_ENTRIES` to `PETSC_TRUE` during assembly, restoring its previous value afterwards.

 86: .seealso: [](ch_matrices), `Mat`, `PetscRandom`, `PetscRandomCreate()`, `MatZeroEntries()`, `MatSetValues()`, `PetscRandomDestroy()`
 87: @*/
 88: PetscErrorCode MatSetRandom(Mat x, PetscRandom rctx)
 89: {
 90:   PetscRandom randObj = NULL;

 92:   PetscFunctionBegin;
 96:   PetscCheck(x->insertmode == NOT_SET_VALUES, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for matrices where you have set values but not yet assembled");
 97:   MatCheckPreallocated(x, 1);

 99:   if (!rctx) {
100:     MPI_Comm comm;
101:     PetscCall(PetscObjectGetComm((PetscObject)x, &comm));
102:     PetscCall(PetscRandomCreate(comm, &randObj));
103:     PetscCall(PetscRandomSetType(randObj, x->defaultrandtype));
104:     PetscCall(PetscRandomSetFromOptions(randObj));
105:     rctx = randObj;
106:   }
107:   PetscCall(PetscLogEventBegin(MAT_SetRandom, x, rctx, 0, 0));
108:   PetscUseTypeMethod(x, setrandom, rctx);
109:   PetscCall(PetscLogEventEnd(MAT_SetRandom, x, rctx, 0, 0));

111:   PetscCall(PetscRandomDestroy(&randObj));
112:   PetscFunctionReturn(PETSC_SUCCESS);
113: }

115: /*@
116:   MatCopyHashToXAIJ - copy hash table entries into an XAIJ matrix type

118:   Logically Collective

120:   Input Parameter:
121: . A - A matrix in unassembled, hash table form

123:   Output Parameter:
124: . B - The XAIJ matrix. This can either be `A` or some matrix of equivalent size, e.g. obtained from `A` via `MatDuplicate()`

126:   Example:
127: .vb
128:      PetscCall(MatDuplicate(A, MAT_DO_NOT_COPY_VALUES, &B));
129:      PetscCall(MatCopyHashToXAIJ(A, B));
130: .ve

132:   Level: advanced

134:   Notes:
135:   If `B` is `A`, then the hash table data structure will be destroyed. `B` is assembled

137: .seealso: [](ch_matrices), `Mat`, `MAT_USE_HASH_TABLE`
138: @*/
139: PetscErrorCode MatCopyHashToXAIJ(Mat A, Mat B)
140: {
141:   PetscFunctionBegin;
143:   PetscUseTypeMethod(A, copyhashtoxaij, B);
144:   PetscFunctionReturn(PETSC_SUCCESS);
145: }

147: /*@
148:   MatFactorGetErrorZeroPivot - returns the pivot value that was determined to be zero and the row it occurred in

150:   Logically Collective

152:   Input Parameter:
153: . mat - the factored matrix

155:   Output Parameters:
156: + pivot - the pivot value computed
157: - row   - the row that the zero pivot occurred. This row value must be interpreted carefully due to row reorderings and which processes
158:          the share the matrix

160:   Level: advanced

162:   Notes:
163:   This routine does not work for factorizations done with external packages.

165:   This routine should only be called if `MatGetFactorError()` returns a value of `MAT_FACTOR_NUMERIC_ZEROPIVOT`

167:   This can also be called on non-factored matrices that come from, for example, matrices used in SOR.

169: .seealso: [](ch_matrices), `Mat`, `MatZeroEntries()`, `MatFactor()`, `MatGetFactor()`,
170: `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`, `MatFactorClearError()`,
171: `MAT_FACTOR_NUMERIC_ZEROPIVOT`
172: @*/
173: PetscErrorCode MatFactorGetErrorZeroPivot(Mat mat, PetscReal *pivot, PetscInt *row)
174: {
175:   PetscFunctionBegin;
177:   PetscAssertPointer(pivot, 2);
178:   PetscAssertPointer(row, 3);
179:   *pivot = mat->factorerror_zeropivot_value;
180:   *row   = mat->factorerror_zeropivot_row;
181:   PetscFunctionReturn(PETSC_SUCCESS);
182: }

184: /*@
185:   MatFactorGetError - gets the error code from a factorization

187:   Logically Collective

189:   Input Parameter:
190: . mat - the factored matrix

192:   Output Parameter:
193: . err - the error code

195:   Level: advanced

197:   Note:
198:   This can also be called on non-factored matrices that come from, for example, matrices used in SOR.

200: .seealso: [](ch_matrices), `Mat`, `MatZeroEntries()`, `MatFactor()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`,
201:           `MatFactorClearError()`, `MatFactorGetErrorZeroPivot()`, `MatFactorError`
202: @*/
203: PetscErrorCode MatFactorGetError(Mat mat, MatFactorError *err)
204: {
205:   PetscFunctionBegin;
207:   PetscAssertPointer(err, 2);
208:   *err = mat->factorerrortype;
209:   PetscFunctionReturn(PETSC_SUCCESS);
210: }

212: /*@
213:   MatFactorClearError - clears the error code in a factorization

215:   Logically Collective

217:   Input Parameter:
218: . mat - the factored matrix

220:   Level: developer

222:   Note:
223:   This can also be called on non-factored matrices that come from, for example, matrices used in SOR.

225: .seealso: [](ch_matrices), `Mat`, `MatZeroEntries()`, `MatFactor()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`, `MatFactorGetError()`, `MatFactorGetErrorZeroPivot()`,
226:           `MatGetErrorCode()`, `MatFactorError`
227: @*/
228: PetscErrorCode MatFactorClearError(Mat mat)
229: {
230:   PetscFunctionBegin;
232:   mat->factorerrortype             = MAT_FACTOR_NOERROR;
233:   mat->factorerror_zeropivot_value = 0.0;
234:   mat->factorerror_zeropivot_row   = 0;
235:   PetscFunctionReturn(PETSC_SUCCESS);
236: }

238: PetscErrorCode MatFindNonzeroRowsOrCols_Basic(Mat mat, PetscBool cols, PetscReal tol, IS *nonzero)
239: {
240:   Vec                r, l;
241:   const PetscScalar *al;
242:   PetscInt           i, nz, gnz, N, n, st;

244:   PetscFunctionBegin;
245:   PetscCall(MatCreateVecs(mat, &r, &l));
246:   if (!cols) { /* nonzero rows */
247:     PetscCall(MatGetOwnershipRange(mat, &st, NULL));
248:     PetscCall(MatGetSize(mat, &N, NULL));
249:     PetscCall(MatGetLocalSize(mat, &n, NULL));
250:     PetscCall(VecSetRandom(r, NULL));
251:     PetscCall(MatMult(mat, r, l));
252:     PetscCall(VecGetArrayRead(l, &al));
253:   } else { /* nonzero columns */
254:     PetscCall(MatGetOwnershipRangeColumn(mat, &st, NULL));
255:     PetscCall(MatGetSize(mat, NULL, &N));
256:     PetscCall(MatGetLocalSize(mat, NULL, &n));
257:     PetscCall(VecSet(r, 0.0));
258:     PetscCall(VecSetRandom(l, NULL));
259:     PetscCall(MatMultTranspose(mat, l, r));
260:     PetscCall(VecGetArrayRead(r, &al));
261:   }
262:   if (tol <= 0.0) {
263:     for (i = 0, nz = 0; i < n; i++)
264:       if (al[i] != 0.0) nz++;
265:   } else {
266:     for (i = 0, nz = 0; i < n; i++)
267:       if (PetscAbsScalar(al[i]) > tol) nz++;
268:   }
269:   PetscCallMPI(MPIU_Allreduce(&nz, &gnz, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)mat)));
270:   if (gnz != N) {
271:     PetscInt *nzr;
272:     PetscCall(PetscMalloc1(nz, &nzr));
273:     if (nz) {
274:       if (tol < 0) {
275:         for (i = 0, nz = 0; i < n; i++)
276:           if (al[i] != 0.0) nzr[nz++] = i + st;
277:       } else {
278:         for (i = 0, nz = 0; i < n; i++)
279:           if (PetscAbsScalar(al[i]) > tol) nzr[nz++] = i + st;
280:       }
281:     }
282:     PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), nz, nzr, PETSC_OWN_POINTER, nonzero));
283:   } else *nonzero = NULL;
284:   if (!cols) { /* nonzero rows */
285:     PetscCall(VecRestoreArrayRead(l, &al));
286:   } else {
287:     PetscCall(VecRestoreArrayRead(r, &al));
288:   }
289:   PetscCall(VecDestroy(&l));
290:   PetscCall(VecDestroy(&r));
291:   PetscFunctionReturn(PETSC_SUCCESS);
292: }

294: /*@
295:   MatFindNonzeroRows - Locate all rows that are not completely zero in the matrix

297:   Input Parameter:
298: . mat - the matrix

300:   Output Parameter:
301: . keptrows - the rows that are not completely zero

303:   Level: intermediate

305:   Note:
306:   `keptrows` is set to `NULL` if all rows are nonzero.

308:   Developer Note:
309:   If `keptrows` is not `NULL`, it must be sorted.

311: .seealso: [](ch_matrices), `Mat`, `MatFindZeroRows()`
312:  @*/
313: PetscErrorCode MatFindNonzeroRows(Mat mat, IS *keptrows)
314: {
315:   PetscFunctionBegin;
318:   PetscAssertPointer(keptrows, 2);
319:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
320:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
321:   if (mat->ops->findnonzerorows) PetscUseTypeMethod(mat, findnonzerorows, keptrows);
322:   else PetscCall(MatFindNonzeroRowsOrCols_Basic(mat, PETSC_FALSE, 0.0, keptrows));
323:   if (keptrows && *keptrows) PetscCall(ISSetInfo(*keptrows, IS_SORTED, IS_GLOBAL, PETSC_FALSE, PETSC_TRUE));
324:   PetscFunctionReturn(PETSC_SUCCESS);
325: }

327: /*@
328:   MatFindZeroRows - Locate all rows that are completely zero in the matrix

330:   Input Parameter:
331: . mat - the matrix

333:   Output Parameter:
334: . zerorows - the rows that are completely zero

336:   Level: intermediate

338:   Note:
339:   `zerorows` is set to `NULL` if no rows are zero.

341: .seealso: [](ch_matrices), `Mat`, `MatFindNonzeroRows()`
342:  @*/
343: PetscErrorCode MatFindZeroRows(Mat mat, IS *zerorows)
344: {
345:   IS       keptrows;
346:   PetscInt m, n;

348:   PetscFunctionBegin;
351:   PetscAssertPointer(zerorows, 2);
352:   PetscCall(MatFindNonzeroRows(mat, &keptrows));
353:   /* MatFindNonzeroRows sets keptrows to NULL if there are no zero rows.
354:      In keeping with this convention, we set zerorows to NULL if there are no zero
355:      rows. */
356:   if (keptrows == NULL) {
357:     *zerorows = NULL;
358:   } else {
359:     PetscCall(MatGetOwnershipRange(mat, &m, &n));
360:     PetscCall(ISComplement(keptrows, m, n, zerorows));
361:     PetscCall(ISDestroy(&keptrows));
362:   }
363:   PetscFunctionReturn(PETSC_SUCCESS);
364: }

366: /*@
367:   MatGetDiagonalBlock - Returns the part of the matrix associated with the on-process coupling

369:   Not Collective

371:   Input Parameter:
372: . A - the matrix

374:   Output Parameter:
375: . a - the diagonal part (which is a SEQUENTIAL matrix)

377:   Level: advanced

379:   Notes:
380:   See `MatCreateAIJ()` for more information on the "diagonal part" of the matrix.

382:   Use caution, as the reference count on the returned matrix is not incremented and it is used as part of `A`'s normal operation.

384: .seealso: [](ch_matrices), `Mat`, `MatCreateAIJ()`, `MATAIJ`, `MATBAIJ`, `MATSBAIJ`
385: @*/
386: PetscErrorCode MatGetDiagonalBlock(Mat A, Mat *a)
387: {
388:   PetscFunctionBegin;
391:   PetscAssertPointer(a, 2);
392:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
393:   if (A->ops->getdiagonalblock) PetscUseTypeMethod(A, getdiagonalblock, a);
394:   else {
395:     PetscMPIInt size;

397:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
398:     PetscCheck(size == 1, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Not for parallel matrix type %s", ((PetscObject)A)->type_name);
399:     *a = A;
400:   }
401:   PetscFunctionReturn(PETSC_SUCCESS);
402: }

404: /*@
405:   MatGetMultPetscSF - Returns the `PetscSF` that communicates to each MPI process the values held on other MPI processes that are coupled to it by the `Mat`

407:   Not Collective

409:   Input Parameter:
410: . A - the matrix

412:   Output Parameter:
413: . sf - the `PetscSF`.

415:   Level: advanced

417:   Notes:
418:   The returned `PetscSF` is owned by the matrix; do not destroy it.

420:   It is only valid if this function is called after the matrix has been assembled
421:   (and for `MATMPIDENSE` after a `MatMult()` has been additionally called).

423:   This is only implemented for the matrix types listed below; calling it on a sequential matrix or a type that does not
424:   build such a `PetscSF` raises an error.

426:   For `MATMPIAIJ`, `MATMPIBAIJ`, `MATMPIDENSE`, and `MATMPISELL`, this `PetscSF` is used within
427:   `MatMult()` to provide the contribution of vector entries that are not local to each MPI process to the matrix-vector product.
428:   For `MATMPISBAIJ` the returned `PetscSF` is instead the off-process column gather used by operations such as
429:   `MatDiagonalScale()`; `MatMult_MPISBAIJ()` uses a separate, augmented scatter context.
430:   In all cases the `PetscSF` maps the global vector layout (the matrix column layout) onto the off-process columns that the local rows couple to,
431:   so it can be reused to communicate any per-column data, for example with `PetscSFBcastBegin()`.

433:   For `MATMPIDENSE` this `PetscSF` is an allgather: every process gathers all columns, including its own, in the natural global
434:   order rather than a sparse `garray` order. The leaf set and ordering therefore differ across matrix types, so callers should use
435:   `PetscSFGetGraph()` rather than assume a particular leaf layout.

437: .seealso: [](ch_matrices), `Mat`, `PetscSF`, `MatGetDiagonalBlock()`, `MatMPIAIJGetSeqAIJ()`, `PetscSFBcastBegin()`, `MatMult()`
438: @*/
439: PetscErrorCode MatGetMultPetscSF(Mat A, PetscSF *sf)
440: {
441:   PetscFunctionBegin;
444:   PetscAssertPointer(sf, 2);
445:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
446:   *sf = NULL;
447:   PetscUseMethod(A, "MatGetMultPetscSF_C", (Mat, PetscSF *), (A, sf));
448:   PetscFunctionReturn(PETSC_SUCCESS);
449: }

451: /*@
452:   MatGetTrace - Gets the trace of a matrix. The sum of the diagonal entries.

454:   Collective

456:   Input Parameter:
457: . mat - the matrix

459:   Output Parameter:
460: . trace - the sum of the diagonal entries

462:   Level: advanced

464: .seealso: [](ch_matrices), `Mat`
465: @*/
466: PetscErrorCode MatGetTrace(Mat mat, PetscScalar *trace)
467: {
468:   Vec diag;

470:   PetscFunctionBegin;
472:   PetscAssertPointer(trace, 2);
473:   PetscCall(MatCreateVecs(mat, &diag, NULL));
474:   PetscCall(MatGetDiagonal(mat, diag));
475:   PetscCall(VecSum(diag, trace));
476:   PetscCall(VecDestroy(&diag));
477:   PetscFunctionReturn(PETSC_SUCCESS);
478: }

480: /*@
481:   MatRealPart - Zeros out the imaginary part of the matrix

483:   Logically Collective

485:   Input Parameter:
486: . mat - the matrix

488:   Level: advanced

490: .seealso: [](ch_matrices), `Mat`, `MatImaginaryPart()`
491: @*/
492: PetscErrorCode MatRealPart(Mat mat)
493: {
494:   PetscFunctionBegin;
497:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
498:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
499:   MatCheckPreallocated(mat, 1);
500:   PetscUseTypeMethod(mat, realpart);
501:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
502:   PetscFunctionReturn(PETSC_SUCCESS);
503: }

505: /*@
506:   MatGetGhosts - Get the global indices of all ghost nodes defined by the sparse matrix

508:   Collective

510:   Input Parameter:
511: . mat - the matrix

513:   Output Parameters:
514: + nghosts - number of ghosts (for `MATBAIJ` and `MATSBAIJ` matrices there is one ghost for each matrix block)
515: - ghosts  - the global indices of the ghost points

517:   Level: advanced

519:   Note:
520:   `nghosts` and `ghosts` are suitable to pass into `VecCreateGhost()` or `VecCreateGhostBlock()`

522: .seealso: [](ch_matrices), `Mat`, `VecCreateGhost()`, `VecCreateGhostBlock()`
523: @*/
524: PetscErrorCode MatGetGhosts(Mat mat, PetscInt *nghosts, const PetscInt *ghosts[])
525: {
526:   PetscFunctionBegin;
529:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
530:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
531:   if (mat->ops->getghosts) PetscUseTypeMethod(mat, getghosts, nghosts, ghosts);
532:   else {
533:     if (nghosts) *nghosts = 0;
534:     if (ghosts) *ghosts = NULL;
535:   }
536:   PetscFunctionReturn(PETSC_SUCCESS);
537: }

539: /*@
540:   MatImaginaryPart - Moves the imaginary part of the matrix to the real part and zeros the imaginary part

542:   Logically Collective

544:   Input Parameter:
545: . mat - the matrix

547:   Level: advanced

549: .seealso: [](ch_matrices), `Mat`, `MatRealPart()`
550: @*/
551: PetscErrorCode MatImaginaryPart(Mat mat)
552: {
553:   PetscFunctionBegin;
556:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
557:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
558:   MatCheckPreallocated(mat, 1);
559:   PetscUseTypeMethod(mat, imaginarypart);
560:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
561:   PetscFunctionReturn(PETSC_SUCCESS);
562: }

564: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
565: /*@
566:   MatGetRow - Gets a row of a matrix. You MUST call `MatRestoreRow()`
567:   for each row that you get to ensure that your application does
568:   not bleed memory.

570:   Not Collective

572:   Input Parameters:
573: + mat - the matrix
574: - row - the row to get

576:   Output Parameters:
577: + ncols - if not `NULL`, the number of nonzeros in `row`
578: . cols  - if not `NULL`, the column numbers
579: - vals  - if not `NULL`, the numerical values

581:   Level: advanced

583:   Notes:
584:   This routine is provided for people who need to have direct access
585:   to the structure of a matrix. We hope that we provide enough
586:   high-level matrix routines that few users will need it.

588:   `MatGetRow()` always returns 0-based column indices, regardless of
589:   whether the internal representation is 0-based (default) or 1-based.

591:   For better efficiency, set `cols` and/or `vals` to `NULL` if you do
592:   not wish to extract these quantities. `vals` must be `NULL` for a matrix with
593:   the `MAT_STRUCTURE_ONLY` option set to true, since no numerical values are stored.

595:   The user can only examine the values extracted with `MatGetRow()`;
596:   the values CANNOT be altered. To change the matrix entries, one
597:   must use `MatSetValues()`.

599:   You can only have one call to `MatGetRow()` outstanding for a particular
600:   matrix at a time, per process. `MatGetRow()` can only obtain rows
601:   associated with the given process, it cannot get rows from the
602:   other processes; for that we suggest using `MatCreateSubMatrices()`, then
603:   `MatGetRow()` on the submatrix. The row index passed to `MatGetRow()`
604:   is in the global number of rows.

606:   Use `MatGetRowIJ()` and `MatRestoreRowIJ()` to access all the local indices of the sparse matrix.

608:   Use `MatSeqAIJGetArray()` and similar functions to access the numerical values for certain matrix types directly.

610:   Fortran Note:
611: .vb
612:   PetscInt, pointer :: cols(:)
613:   PetscScalar, pointer :: vals(:)
614: .ve

616: .seealso: [](ch_matrices), `Mat`, `MatRestoreRow()`, `MatSetValues()`, `MatGetValues()`, `MatCreateSubMatrices()`, `MatGetDiagonal()`, `MatGetRowIJ()`, `MatRestoreRowIJ()`
617: @*/
618: PetscErrorCode MatGetRow(Mat mat, PetscInt row, PetscInt *ncols, const PetscInt *cols[], const PetscScalar *vals[])
619: {
620:   PetscInt incols;

622:   PetscFunctionBegin;
625:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
626:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
627:   PetscCheck(!mat->structure_only || vals == NULL, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for matrix with MAT_STRUCTURE_ONLY");
628:   MatCheckPreallocated(mat, 1);
629:   PetscCheck(row >= mat->rmap->rstart && row < mat->rmap->rend, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Only for local rows, %" PetscInt_FMT " not in [%" PetscInt_FMT ",%" PetscInt_FMT ")", row, mat->rmap->rstart, mat->rmap->rend);
630:   PetscCall(PetscLogEventBegin(MAT_GetRow, mat, 0, 0, 0));
631:   PetscUseTypeMethod(mat, getrow, row, &incols, (PetscInt **)cols, (PetscScalar **)vals);
632:   if (ncols) *ncols = incols;
633:   PetscCall(PetscLogEventEnd(MAT_GetRow, mat, 0, 0, 0));
634:   PetscFunctionReturn(PETSC_SUCCESS);
635: }

637: /*@
638:   MatConjugate - replaces the matrix values with their complex conjugates

640:   Logically Collective

642:   Input Parameter:
643: . mat - the matrix

645:   Level: advanced

647: .seealso: [](ch_matrices), `Mat`, `MatRealPart()`, `MatImaginaryPart()`, `VecConjugate()`, `MatTranspose()`
648: @*/
649: PetscErrorCode MatConjugate(Mat mat)
650: {
651:   PetscFunctionBegin;
653:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
654:   if (PetscDefined(USE_COMPLEX) && !(mat->symmetric == PETSC_BOOL3_TRUE && mat->hermitian == PETSC_BOOL3_TRUE)) {
655:     PetscUseTypeMethod(mat, conjugate);
656:     PetscCall(PetscObjectStateIncrease((PetscObject)mat));
657:   }
658:   PetscFunctionReturn(PETSC_SUCCESS);
659: }

661: /*@
662:   MatRestoreRow - Frees any temporary space allocated by `MatGetRow()`.

664:   Not Collective

666:   Input Parameters:
667: + mat   - the matrix
668: . row   - the row to get
669: . ncols - the number of nonzeros
670: . cols  - the columns of the nonzeros
671: - vals  - if nonzero the column values

673:   Level: advanced

675:   Notes:
676:   This routine should be called after you have finished examining the entries.

678:   This routine zeros out `ncols`, `cols`, and `vals`. This is to prevent accidental
679:   us of the array after it has been restored. If you pass `NULL`, it will
680:   not zero the pointers. Use of `cols` or `vals` after `MatRestoreRow()` is invalid.

682:   Fortran Note:
683: .vb
684:   PetscInt, pointer :: cols(:)
685:   PetscScalar, pointer :: vals(:)
686: .ve

688: .seealso: [](ch_matrices), `Mat`, `MatGetRow()`
689: @*/
690: PetscErrorCode MatRestoreRow(Mat mat, PetscInt row, PetscInt *ncols, const PetscInt *cols[], const PetscScalar *vals[])
691: {
692:   PetscFunctionBegin;
694:   if (ncols) PetscAssertPointer(ncols, 3);
695:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
696:   PetscTryTypeMethod(mat, restorerow, row, ncols, (PetscInt **)cols, (PetscScalar **)vals);
697:   if (ncols) *ncols = 0;
698:   if (cols) *cols = NULL;
699:   if (vals) *vals = NULL;
700:   PetscFunctionReturn(PETSC_SUCCESS);
701: }

703: /*@
704:   MatGetRowUpperTriangular - Sets a flag to enable calls to `MatGetRow()` for matrix in `MATSBAIJ` format.
705:   You should call `MatRestoreRowUpperTriangular()` after calling` MatGetRow()` and `MatRestoreRow()` to disable the flag.

707:   Not Collective

709:   Input Parameter:
710: . mat - the matrix

712:   Level: advanced

714:   Note:
715:   The flag is to ensure that users are aware that `MatGetRow()` only provides the upper triangular part of the row for the matrices in `MATSBAIJ` format.

717: .seealso: [](ch_matrices), `Mat`, `MATSBAIJ`, `MatRestoreRowUpperTriangular()`
718: @*/
719: PetscErrorCode MatGetRowUpperTriangular(Mat mat)
720: {
721:   PetscFunctionBegin;
724:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
725:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
726:   MatCheckPreallocated(mat, 1);
727:   PetscTryTypeMethod(mat, getrowuppertriangular);
728:   PetscFunctionReturn(PETSC_SUCCESS);
729: }

731: /*@
732:   MatRestoreRowUpperTriangular - Disable calls to `MatGetRow()` for matrix in `MATSBAIJ` format.

734:   Not Collective

736:   Input Parameter:
737: . mat - the matrix

739:   Level: advanced

741:   Note:
742:   This routine should be called after you have finished calls to `MatGetRow()` and `MatRestoreRow()`.

744: .seealso: [](ch_matrices), `Mat`, `MATSBAIJ`, `MatGetRowUpperTriangular()`
745: @*/
746: PetscErrorCode MatRestoreRowUpperTriangular(Mat mat)
747: {
748:   PetscFunctionBegin;
751:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
752:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
753:   MatCheckPreallocated(mat, 1);
754:   PetscTryTypeMethod(mat, restorerowuppertriangular);
755:   PetscFunctionReturn(PETSC_SUCCESS);
756: }

758: /*@
759:   MatSetOptionsPrefix - Sets the prefix used for searching for all
760:   `Mat` options in the database.

762:   Logically Collective

764:   Input Parameters:
765: + A      - the matrix
766: - prefix - the prefix to prepend to all option names

768:   Level: advanced

770:   Notes:
771:   A hyphen (-) must NOT be given at the beginning of the prefix name.
772:   The first character of all runtime options is AUTOMATICALLY the hyphen.

774:   This is NOT used for options for the factorization of the matrix. Normally the
775:   prefix is automatically passed in from the PC calling the factorization. To set
776:   it directly use  `MatSetOptionsPrefixFactor()`

778: .seealso: [](ch_matrices), `Mat`, `MatSetFromOptions()`, `MatSetOptionsPrefixFactor()`
779: @*/
780: PetscErrorCode MatSetOptionsPrefix(Mat A, const char prefix[])
781: {
782:   PetscFunctionBegin;
784:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)A, prefix));
785:   PetscTryMethod(A, "MatSetOptionsPrefix_C", (Mat, const char[]), (A, prefix));
786:   PetscFunctionReturn(PETSC_SUCCESS);
787: }

789: /*@
790:   MatSetOptionsPrefixFactor - Sets the prefix used for searching for all matrix factor options in the database for
791:   for matrices created with `MatGetFactor()`

793:   Logically Collective

795:   Input Parameters:
796: + A      - the matrix
797: - prefix - the prefix to prepend to all option names for the factored matrix

799:   Level: developer

801:   Notes:
802:   A hyphen (-) must NOT be given at the beginning of the prefix name.
803:   The first character of all runtime options is AUTOMATICALLY the hyphen.

805:   Normally the prefix is automatically passed in from the `PC` calling the factorization. To set
806:   it directly when not using `KSP`/`PC` use  `MatSetOptionsPrefixFactor()`

808: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSetFromOptions()`, `MatSetOptionsPrefix()`, `MatAppendOptionsPrefixFactor()`
809: @*/
810: PetscErrorCode MatSetOptionsPrefixFactor(Mat A, const char prefix[])
811: {
812:   PetscFunctionBegin;
814:   if (prefix) {
815:     PetscAssertPointer(prefix, 2);
816:     PetscCheck(prefix[0] != '-', PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Options prefix should not begin with a hyphen");
817:     if (prefix != A->factorprefix) {
818:       PetscCall(PetscFree(A->factorprefix));
819:       PetscCall(PetscStrallocpy(prefix, &A->factorprefix));
820:     }
821:   } else PetscCall(PetscFree(A->factorprefix));
822:   PetscFunctionReturn(PETSC_SUCCESS);
823: }

825: /*@
826:   MatAppendOptionsPrefixFactor - Appends to the prefix used for searching for all matrix factor options in the database for
827:   for matrices created with `MatGetFactor()`

829:   Logically Collective

831:   Input Parameters:
832: + A      - the matrix
833: - prefix - the prefix to prepend to all option names for the factored matrix

835:   Level: developer

837:   Notes:
838:   A hyphen (-) must NOT be given at the beginning of the prefix name.
839:   The first character of all runtime options is AUTOMATICALLY the hyphen.

841:   Normally the prefix is automatically passed in from the `PC` calling the factorization. To set
842:   it directly when not using `KSP`/`PC` use  `MatAppendOptionsPrefixFactor()`

844: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `PetscOptionsCreate()`, `PetscOptionsDestroy()`, `PetscObjectSetOptionsPrefix()`, `PetscObjectPrependOptionsPrefix()`,
845:           `PetscObjectGetOptionsPrefix()`, `TSAppendOptionsPrefix()`, `SNESAppendOptionsPrefix()`, `KSPAppendOptionsPrefix()`, `MatSetOptionsPrefixFactor()`,
846:           `MatSetOptionsPrefix()`
847: @*/
848: PetscErrorCode MatAppendOptionsPrefixFactor(Mat A, const char prefix[])
849: {
850:   size_t len1, len2, new_len;

852:   PetscFunctionBegin;
854:   if (!prefix) PetscFunctionReturn(PETSC_SUCCESS);
855:   if (!A->factorprefix) {
856:     PetscCall(MatSetOptionsPrefixFactor(A, prefix));
857:     PetscFunctionReturn(PETSC_SUCCESS);
858:   }
859:   PetscCheck(prefix[0] != '-', PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Options prefix should not begin with a hyphen");

861:   PetscCall(PetscStrlen(A->factorprefix, &len1));
862:   PetscCall(PetscStrlen(prefix, &len2));
863:   new_len = len1 + len2 + 1;
864:   PetscCall(PetscRealloc(new_len * sizeof(*A->factorprefix), &A->factorprefix));
865:   PetscCall(PetscStrncpy(A->factorprefix + len1, prefix, len2 + 1));
866:   PetscFunctionReturn(PETSC_SUCCESS);
867: }

869: /*@
870:   MatAppendOptionsPrefix - Appends to the prefix used for searching for all
871:   matrix options in the database.

873:   Logically Collective

875:   Input Parameters:
876: + A      - the matrix
877: - prefix - the prefix to prepend to all option names

879:   Level: advanced

881:   Note:
882:   A hyphen (-) must NOT be given at the beginning of the prefix name.
883:   The first character of all runtime options is AUTOMATICALLY the hyphen.

885: .seealso: [](ch_matrices), `Mat`, `MatGetOptionsPrefix()`, `MatAppendOptionsPrefixFactor()`, `MatSetOptionsPrefix()`
886: @*/
887: PetscErrorCode MatAppendOptionsPrefix(Mat A, const char prefix[])
888: {
889:   PetscFunctionBegin;
891:   PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)A, prefix));
892:   PetscTryMethod(A, "MatAppendOptionsPrefix_C", (Mat, const char[]), (A, prefix));
893:   PetscFunctionReturn(PETSC_SUCCESS);
894: }

896: /*@
897:   MatGetOptionsPrefix - Gets the prefix used for searching for all
898:   matrix options in the database.

900:   Not Collective

902:   Input Parameter:
903: . A - the matrix

905:   Output Parameter:
906: . prefix - pointer to the prefix string used

908:   Level: advanced

910: .seealso: [](ch_matrices), `Mat`, `MatAppendOptionsPrefix()`, `MatSetOptionsPrefix()`, `MatAppendOptionsPrefixFactor()`, `MatSetOptionsPrefixFactor()`
911: @*/
912: PetscErrorCode MatGetOptionsPrefix(Mat A, const char *prefix[])
913: {
914:   PetscFunctionBegin;
916:   PetscAssertPointer(prefix, 2);
917:   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)A, prefix));
918:   PetscFunctionReturn(PETSC_SUCCESS);
919: }

921: /*@
922:   MatGetState - Gets a snapshot of the state of a `Mat`

924:   Not Collective

926:   Input Parameter:
927: . A - the matrix

929:   Output Parameter:
930: . state - the matrix state

932:   Level: developer

934:   Note:
935:   The snapshot includes the matrix object id, state, and nonzero state. Use `MatStateCompare()` to determine whether two snapshots are the same, or `MatStateCompareUpdate()` to compare and update a saved snapshot.

937: .seealso: [](ch_matrices), `Mat`, `MatState`, `MatStateCompare()`, `MatStateCompareUpdate()`, `MatStateInvalidate()`, `PetscObjectStateGet()`, `PetscObjectGetId()`, `MatGetNonzeroState()`
938: @*/
939: PetscErrorCode MatGetState(Mat A, MatState *state)
940: {
941:   PetscFunctionBegin;
943:   PetscAssertPointer(state, 2);
944:   state->id           = ((PetscObject)A)->id;
945:   state->state        = ((PetscObject)A)->state;
946:   state->nonzerostate = A->nonzerostate;
947:   PetscFunctionReturn(PETSC_SUCCESS);
948: }

950: /*@
951:   MatStateCompare - Compares two matrix state snapshots

953:   Not Collective

955:   Input Parameters:
956: + state1 - the first matrix state
957: - state2 - the second matrix state

959:   Output Parameter:
960: . same - `PETSC_TRUE` if the matrix object id, state, and nonzero state are the same, `PETSC_FALSE` otherwise

962:   Level: developer

964: .seealso: [](ch_matrices), `Mat`, `MatState`, `MatGetState()`, `MatStateCompareUpdate()`, `MatStateInvalidate()`
965: @*/
966: PetscErrorCode MatStateCompare(MatState state1, MatState state2, PetscBool *same)
967: {
968:   PetscFunctionBegin;
969:   PetscAssertPointer(same, 3);
970:   *same = (PetscBool)(state1.id == state2.id && state1.state == state2.state && state1.nonzerostate == state2.nonzerostate);
971:   PetscFunctionReturn(PETSC_SUCCESS);
972: }

974: /*@
975:   MatStateCompareUpdate - Compares a matrix with a state snapshot, then updates the snapshot

977:   Not Collective

979:   Input Parameter:
980: . A - the matrix

982:   Input/Output Parameter:
983: . state - the matrix state snapshot to compare with and update

985:   Output Parameter:
986: . same - `PETSC_TRUE` if the matrix state matched the snapshot before it was updated, `PETSC_FALSE` otherwise

988:   Level: developer

990: .seealso: [](ch_matrices), `Mat`, `MatState`, `MatGetState()`, `MatStateCompare()`, `MatStateInvalidate()`
991: @*/
992: PetscErrorCode MatStateCompareUpdate(Mat A, MatState *state, PetscBool *same)
993: {
994:   MatState current;

996:   PetscFunctionBegin;
998:   PetscAssertPointer(state, 2);
999:   PetscAssertPointer(same, 3);
1000:   PetscCall(MatGetState(A, &current));
1001:   PetscCall(MatStateCompare(current, *state, same));
1002:   *state = current;
1003:   PetscFunctionReturn(PETSC_SUCCESS);
1004: }

1006: /*@
1007:   MatResetPreallocation - Reset matrix to use the original preallocation values provided by the user, for example with `MatXAIJSetPreallocation()`

1009:   Collective

1011:   Input Parameter:
1012: . A - the matrix

1014:   Level: beginner

1016:   Notes:
1017:   After calling `MatAssemblyBegin()` and `MatAssemblyEnd()` with `MAT_FINAL_ASSEMBLY` the matrix data structures represent the nonzeros assigned to the
1018:   matrix. If that space is less than the preallocated space that extra preallocated space is no longer available to take on new values. `MatResetPreallocation()`
1019:   makes all of the preallocation space available

1021:   Current values in the matrix are lost in this call

1023:   Currently only supported for  `MATAIJ` matrices.

1025: .seealso: [](ch_matrices), `Mat`, `MatSeqAIJSetPreallocation()`, `MatMPIAIJSetPreallocation()`, `MatXAIJSetPreallocation()`
1026: @*/
1027: PetscErrorCode MatResetPreallocation(Mat A)
1028: {
1029:   PetscFunctionBegin;
1032:   PetscUseMethod(A, "MatResetPreallocation_C", (Mat), (A));
1033:   PetscFunctionReturn(PETSC_SUCCESS);
1034: }

1036: /*@
1037:   MatResetHash - Reset the matrix so that it will use a hash table for the next round of `MatSetValues()` and `MatAssemblyBegin()`/`MatAssemblyEnd()`.

1039:   Collective

1041:   Input Parameter:
1042: . A - the matrix

1044:   Level: intermediate

1046:   Notes:
1047:   The matrix will again delete the hash table data structures after following calls to `MatAssemblyBegin()`/`MatAssemblyEnd()` with `MAT_FINAL_ASSEMBLY`.

1049:   Currently only supported for `MATAIJ` matrices.

1051: .seealso: [](ch_matrices), `Mat`, `MatResetPreallocation()`
1052: @*/
1053: PetscErrorCode MatResetHash(Mat A)
1054: {
1055:   PetscFunctionBegin;
1058:   PetscCheck(A->insertmode == NOT_SET_VALUES, PETSC_COMM_SELF, PETSC_ERR_SUP, "Cannot reset to hash state after setting some values but not yet calling MatAssemblyBegin()/MatAssemblyEnd()");
1059:   if (A->num_ass == 0) PetscFunctionReturn(PETSC_SUCCESS);
1060:   PetscUseMethod(A, "MatResetHash_C", (Mat), (A));
1061:   /* These flags are used to determine whether certain setups occur */
1062:   A->was_assembled = PETSC_FALSE;
1063:   A->assembled     = PETSC_FALSE;
1064:   /* Log that the state of this object has changed; this will help guarantee that preconditioners get re-setup */
1065:   PetscCall(PetscObjectStateIncrease((PetscObject)A));
1066:   PetscFunctionReturn(PETSC_SUCCESS);
1067: }

1069: /*@
1070:   MatSetUp - Sets up the internal matrix data structures for later use by the matrix

1072:   Collective

1074:   Input Parameter:
1075: . A - the matrix

1077:   Level: advanced

1079:   Notes:
1080:   If no preallocation has been provided for a `MATAIJ`, `MATBAIJ`, or `MATSBAIJ` matrix, `MatSetUp()` makes it record the
1081:   values given to `MatSetValues()` in a hash table, and the first assembly determines the nonzero pattern from it. Providing
1082:   preallocation instead, for example with `MatXAIJSetPreallocation()` or `MatSetPreallocationCOO()`, disables hash-table mode.

1084:   This routine is called internally by other `Mat` functions when needed so rarely needs to be called by users

1086: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatCreate()`, `MatDestroy()`, `MatXAIJSetPreallocation()`
1087: @*/
1088: PetscErrorCode MatSetUp(Mat A)
1089: {
1090:   PetscFunctionBegin;
1092:   if (!((PetscObject)A)->type_name) {
1093:     PetscMPIInt size;

1095:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
1096:     PetscCall(MatSetType(A, size == 1 ? MATSEQAIJ : MATMPIAIJ));
1097:   }
1098:   if (!A->preallocated) PetscTryTypeMethod(A, setup);
1099:   PetscCall(PetscLayoutSetUp(A->rmap));
1100:   PetscCall(PetscLayoutSetUp(A->cmap));
1101:   A->preallocated = PETSC_TRUE;
1102:   PetscFunctionReturn(PETSC_SUCCESS);
1103: }

1105: #if PetscDefined(HAVE_SAWS)
1106: #include <petscviewersaws.h>
1107: #endif

1109: /*
1110:    If threadsafety is on extraneous matrices may be printed

1112:    This flag cannot be stored in the matrix because the original matrix in MatView() may assemble a new matrix which is passed into MatViewFromOptions()
1113: */
1114: #if !PetscDefined(HAVE_THREADSAFETY)
1115: static PetscInt insidematview = 0;
1116: #endif

1118: /*@
1119:   MatViewFromOptions - View properties of the matrix based on options set in the options database

1121:   Collective

1123:   Input Parameters:
1124: + A    - the matrix
1125: . obj  - optional additional object that provides the options prefix to use
1126: - name - command line option

1128:   Options Database Key:
1129: . -name viewer_specification - See `PetscOptionsCreateViewer()` for the values of `viewer_specification`

1131:   Level: intermediate

1133:   Note:
1134:   This checks the options database, creates the viewer on-the-fly, uses it and then destroys it. Hence it should not be called in heavily used routines,
1135:   rather `PetscOptionsCreateViewer()` should be used to construct the viewer once which can then be utilized in the heavily used routine.

1137: .seealso: [](ch_matrices), `Mat`, `MatView()`, `PetscObjectViewFromOptions()`, `MatCreate()`, `PetscOptionsCreateViewer()`
1138: @*/
1139: PetscErrorCode MatViewFromOptions(Mat A, PetscObject obj, const char name[])
1140: {
1141:   PetscFunctionBegin;
1143: #if !PetscDefined(HAVE_THREADSAFETY)
1144:   if (insidematview) PetscFunctionReturn(PETSC_SUCCESS);
1145: #endif
1146:   PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
1147:   PetscFunctionReturn(PETSC_SUCCESS);
1148: }

1150: /*@
1151:   MatView - display information about a matrix in a variety ways

1153:   Collective on viewer

1155:   Input Parameters:
1156: + mat    - the matrix
1157: - viewer - visualization context

1159:   Options Database Key:
1160: . -mat_view viewer_specification - Call `MatView()` at the conclusion of `MatAssemblyEnd()` or other routines that have changed the matrix values.
1161:                                    See `PetscOptionsCreateViewer()` for the values of `viewer_specification`.

1163:   Level: beginner

1165:   Notes:
1166:   The available visualization contexts include
1167: +    `PETSC_VIEWER_STDOUT_SELF`   - for sequential matrices
1168: .    `PETSC_VIEWER_STDOUT_WORLD`  - for parallel matrices created on `PETSC_COMM_WORLD`
1169: .    `PETSC_VIEWER_STDOUT_`(comm) - for matrices created on MPI communicator comm
1170: -     `PETSC_VIEWER_DRAW_WORLD`   - graphical display of nonzero structure

1172:   The user can open alternative visualization contexts with
1173: +    `PetscViewerASCIIOpen()`  - Outputs matrix to a specified file
1174: .    `PetscViewerBinaryOpen()` - Outputs matrix in binary to a  specified file; corresponding input uses `MatLoad()`
1175: .    `PetscViewerDrawOpen()`   - Outputs nonzero matrix nonzero structure to an X window display
1176: -    `PetscViewerSocketOpen()` - Outputs matrix to Socket viewer, `PETSCVIEWERSOCKET`. Only the `MATSEQDENSE` and `MATAIJ` types support this viewer.

1178:   The user can call `PetscViewerPushFormat()` to specify the output
1179:   format of ASCII printed objects (when using `PETSC_VIEWER_STDOUT_SELF`,
1180:   `PETSC_VIEWER_STDOUT_WORLD` and `PetscViewerASCIIOpen()`). Available formats include
1181: +    `PETSC_VIEWER_DEFAULT`           - default, prints matrix contents
1182: .    `PETSC_VIEWER_ASCII_MATLAB`      - prints matrix contents in MATLAB format
1183: .    `PETSC_VIEWER_ASCII_DENSE`       - prints entire matrix including zeros
1184: .    `PETSC_VIEWER_ASCII_COMMON`      - prints matrix contents, using a sparse  format common among all matrix types
1185: .    `PETSC_VIEWER_ASCII_IMPL`        - prints matrix contents, using an implementation-specific format (which is in many cases the same as the default)
1186: .    `PETSC_VIEWER_ASCII_INFO`        - prints basic information about the matrix size and structure (not the matrix entries)
1187: -    `PETSC_VIEWER_ASCII_INFO_DETAIL` - prints more detailed information about the matrix nonzero structure (still not vector or matrix entries)

1189:   The ASCII viewers are only recommended for small matrices on at most a moderate number of processes,
1190:   the program will seemingly hang and take hours for larger matrices, for larger matrices one should use the binary format.

1192:   In the debugger you can do "call MatView(mat,0)" to display the matrix. (The same holds for any PETSc object viewer).

1194:   See the manual page for `MatLoad()` for the exact format of the binary file when the binary
1195:   viewer is used.

1197:   `MatViewFromOptions()` provides an alternative to this routine that only views the matrix if the requested value
1198:   is provided in the options database.

1200:   See `share/petsc/matlab/PetscBinaryRead.m` for a MATLAB code that can read in the binary file when the binary
1201:   viewer is used and `lib/petsc/bin/PetscBinaryIO.py` for loading them into Python.

1203:   One can use `-mat_view draw -draw_pause -1` to pause the graphical display of matrix nonzero structure,
1204:   and then use the following mouse functions.
1205: .vb
1206:   left mouse: zoom in
1207:   middle mouse: zoom out
1208:   right mouse: continue with the simulation
1209: .ve

1211: .seealso: [](ch_matrices), `Mat`, `PetscViewerPushFormat()`, `PetscViewerASCIIOpen()`, `PetscViewerDrawOpen()`, `PetscViewer`,
1212:           `PetscViewerSocketOpen()`, `PetscViewerBinaryOpen()`, `MatLoad()`, `MatViewFromOptions()`, `PetscOptionsCreateViewer()`
1213: @*/
1214: PetscErrorCode MatView(Mat mat, PetscViewer viewer)
1215: {
1216:   PetscInt          rows, cols, rbs, cbs;
1217:   PetscBool         isascii, isstring, issaws;
1218:   PetscViewerFormat format;
1219:   PetscMPIInt       size;

1221:   PetscFunctionBegin;
1224:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)mat), &viewer));

1227:   PetscCall(PetscViewerGetFormat(viewer, &format));
1228:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)viewer), &size));
1229:   if (size == 1 && format == PETSC_VIEWER_LOAD_BALANCE) PetscFunctionReturn(PETSC_SUCCESS);

1231: #if !PetscDefined(HAVE_THREADSAFETY)
1232:   insidematview++;
1233: #endif
1234:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
1235:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
1236:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
1237:   PetscCheck((isascii && (format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL)) || !mat->factortype, PetscObjectComm((PetscObject)viewer), PETSC_ERR_ARG_WRONGSTATE, "No viewers for factored matrix except ASCII, info, or info_detail");

1239:   PetscCall(PetscLogEventBegin(MAT_View, mat, viewer, 0, 0));
1240:   if (isascii) {
1241:     if (!mat->preallocated) {
1242:       PetscCall(PetscViewerASCIIPrintf(viewer, "Matrix has not been preallocated yet\n"));
1243: #if !PetscDefined(HAVE_THREADSAFETY)
1244:       insidematview--;
1245: #endif
1246:       PetscCall(PetscLogEventEnd(MAT_View, mat, viewer, 0, 0));
1247:       PetscFunctionReturn(PETSC_SUCCESS);
1248:     }
1249:     if (!mat->assembled) {
1250:       PetscCall(PetscViewerASCIIPrintf(viewer, "Matrix has not been assembled yet\n"));
1251: #if !PetscDefined(HAVE_THREADSAFETY)
1252:       insidematview--;
1253: #endif
1254:       PetscCall(PetscLogEventEnd(MAT_View, mat, viewer, 0, 0));
1255:       PetscFunctionReturn(PETSC_SUCCESS);
1256:     }
1257:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)mat, viewer));
1258:     if (format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
1259:       MatNullSpace nullsp, transnullsp;
1260:       PetscBool    nz_factor = PETSC_TRUE;

1262:       PetscCall(PetscViewerASCIIPushTab(viewer));
1263:       PetscCall(MatGetSize(mat, &rows, &cols));
1264:       PetscCall(MatGetBlockSizes(mat, &rbs, &cbs));
1265:       if (rbs != 1 || cbs != 1) {
1266:         if (rbs != cbs) PetscCall(PetscViewerASCIIPrintf(viewer, "rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT ", rbs=%" PetscInt_FMT ", cbs=%" PetscInt_FMT "%s\n", rows, cols, rbs, cbs, mat->bsizes ? " variable blocks set" : ""));
1267:         else PetscCall(PetscViewerASCIIPrintf(viewer, "rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT ", bs=%" PetscInt_FMT "%s\n", rows, cols, rbs, mat->bsizes ? " variable blocks set" : ""));
1268:       } else PetscCall(PetscViewerASCIIPrintf(viewer, "rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT "\n", rows, cols));
1269:       if (mat->factortype) {
1270:         MatSolverType solver;

1272:         PetscCall(MatFactorGetSolverType(mat, &solver));
1273:         PetscCall(PetscViewerASCIIPrintf(viewer, "package used to perform factorization: %s\n", solver));
1274:         PetscCall(PetscStrcmpAny(solver, &nz_factor, MATSOLVERUMFPACK, MATSOLVERCHOLMOD, MATSOLVERSUPERLU, MATSOLVERSUPERLU_DIST, MATSOLVERSTRUMPACK, MATSOLVERHTOOL, ""));
1275:         nz_factor = !nz_factor;
1276:       }
1277:       if (mat->ops->getinfo) {
1278:         PetscBool is_constant_or_diagonal;

1280:         // Don't print nonzero information for constant or diagonal matrices, it just adds noise to the output
1281:         PetscCall(PetscObjectTypeCompareAny((PetscObject)mat, &is_constant_or_diagonal, MATCONSTANTDIAGONAL, MATDIAGONAL, ""));
1282:         if (!is_constant_or_diagonal && nz_factor) {
1283:           MatInfo info;

1285:           PetscCall(MatGetInfo(mat, MAT_GLOBAL_SUM, &info));
1286:           PetscCall(PetscViewerASCIIPrintf(viewer, "total: nonzeros=%.f, allocated nonzeros=%.f\n", info.nz_used, info.nz_allocated));
1287:           if (!mat->factortype) PetscCall(PetscViewerASCIIPrintf(viewer, "total number of mallocs used during MatSetValues calls=%" PetscInt_FMT "\n", (PetscInt)info.mallocs));
1288:         }
1289:       }
1290:       PetscCall(MatGetNullSpace(mat, &nullsp));
1291:       PetscCall(MatGetTransposeNullSpace(mat, &transnullsp));
1292:       if (nullsp) PetscCall(PetscViewerASCIIPrintf(viewer, "  has attached null space\n"));
1293:       if (transnullsp && transnullsp != nullsp) PetscCall(PetscViewerASCIIPrintf(viewer, "  has attached transposed null space\n"));
1294:       PetscCall(MatGetNearNullSpace(mat, &nullsp));
1295:       if (nullsp) PetscCall(PetscViewerASCIIPrintf(viewer, "  has attached near null space\n"));
1296:       PetscCall(PetscViewerASCIIPushTab(viewer));
1297:       PetscCall(MatProductView(mat, viewer));
1298:       PetscCall(PetscViewerASCIIPopTab(viewer));
1299:       if (mat->bsizes && format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
1300:         IS tmp;

1302:         PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)viewer), mat->nblocks, mat->bsizes, PETSC_USE_POINTER, &tmp));
1303:         PetscCall(PetscObjectSetName((PetscObject)tmp, "Block Sizes"));
1304:         PetscCall(PetscViewerASCIIPushTab(viewer));
1305:         PetscCall(ISView(tmp, viewer));
1306:         PetscCall(PetscViewerASCIIPopTab(viewer));
1307:         PetscCall(ISDestroy(&tmp));
1308:       }
1309:     }
1310:   } else if (issaws) {
1311: #if PetscDefined(HAVE_SAWS)
1312:     PetscMPIInt rank;

1314:     PetscCall(PetscObjectName((PetscObject)mat));
1315:     PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
1316:     if (!((PetscObject)mat)->amsmem && rank == 0) PetscCall(PetscObjectViewSAWs((PetscObject)mat, viewer));
1317: #endif
1318:   } else if (isstring) {
1319:     const char *type;
1320:     PetscCall(MatGetType(mat, &type));
1321:     PetscCall(PetscViewerStringSPrintf(viewer, " MatType: %-7.7s", type));
1322:     PetscTryTypeMethod(mat, view, viewer);
1323:   }
1324:   if ((format == PETSC_VIEWER_NATIVE || format == PETSC_VIEWER_LOAD_BALANCE) && mat->ops->viewnative) {
1325:     PetscCall(PetscViewerASCIIPushTab(viewer));
1326:     PetscUseTypeMethod(mat, viewnative, viewer);
1327:     PetscCall(PetscViewerASCIIPopTab(viewer));
1328:   } else if (mat->ops->view) {
1329:     PetscCall(PetscViewerASCIIPushTab(viewer));
1330:     PetscUseTypeMethod(mat, view, viewer);
1331:     PetscCall(PetscViewerASCIIPopTab(viewer));
1332:   }
1333:   if (isascii) {
1334:     PetscCall(PetscViewerGetFormat(viewer, &format));
1335:     if (format == PETSC_VIEWER_ASCII_INFO || format == PETSC_VIEWER_ASCII_INFO_DETAIL) PetscCall(PetscViewerASCIIPopTab(viewer));
1336:   }
1337:   PetscCall(PetscLogEventEnd(MAT_View, mat, viewer, 0, 0));
1338: #if !PetscDefined(HAVE_THREADSAFETY)
1339:   insidematview--;
1340: #endif
1341:   PetscFunctionReturn(PETSC_SUCCESS);
1342: }

1344: #if PetscDefined(USE_DEBUG)
1345: #include <../src/sys/totalview/tv_data_display.h>
1346: PETSC_UNUSED static int TV_display_type(const struct _p_Mat *mat)
1347: {
1348:   TV_add_row("Local rows", "int", &mat->rmap->n);
1349:   TV_add_row("Local columns", "int", &mat->cmap->n);
1350:   TV_add_row("Global rows", "int", &mat->rmap->N);
1351:   TV_add_row("Global columns", "int", &mat->cmap->N);
1352:   TV_add_row("Typename", TV_ascii_string_type, ((PetscObject)mat)->type_name);
1353:   return TV_format_OK;
1354: }
1355: #endif

1357: /*@
1358:   MatLoad - Loads a matrix that has been stored in binary/HDF5 format
1359:   with `MatView()`. The matrix format is determined from the options database.
1360:   Generates a parallel MPI matrix if the communicator has more than one
1361:   process. The default matrix type is `MATAIJ`.

1363:   Collective

1365:   Input Parameters:
1366: + mat    - the newly loaded matrix, this needs to have been created with `MatCreate()`
1367:             or some related function before a call to `MatLoad()`
1368: - viewer - `PETSCVIEWERBINARY`/`PETSCVIEWERHDF5` file viewer

1370:   Options Database Key:
1371: . -matload_block_size bs - set block size

1373:   Level: beginner

1375:   Notes:
1376:   If the `Mat` type has not yet been given then `MATAIJ` is used, call `MatSetFromOptions()` on the
1377:   `Mat` before calling this routine if you wish to set it from the options database.

1379:   `MatLoad()` automatically loads into the options database any options
1380:   given in the file filename.info where filename is the name of the file
1381:   that was passed to the `PetscViewerBinaryOpen()`. The options in the info
1382:   file will be ignored if you use the `-viewer_binary_skip_info` option.

1384:   If the type or size of mat is not set before a call to `MatLoad()`, PETSc
1385:   sets the default matrix type AIJ and sets the local and global sizes.
1386:   If type and/or size is already set, then the same are used.

1388:   In parallel, each process can load a subset of rows (or the
1389:   entire matrix). This routine is especially useful when a large
1390:   matrix is stored on disk and only part of it is desired on each
1391:   process. For example, a parallel solver may access only some of
1392:   the rows from each process. The algorithm used here reads
1393:   relatively small blocks of data rather than reading the entire
1394:   matrix and then subsetting it.

1396:   Viewer's `PetscViewerType` must be either `PETSCVIEWERBINARY` or `PETSCVIEWERHDF5`.
1397:   Such viewer can be created using `PetscViewerBinaryOpen()` or `PetscViewerHDF5Open()`,
1398:   or the sequence like
1399: .vb
1400:     PetscViewer v;
1401:     PetscViewerCreate(PETSC_COMM_WORLD, &v);
1402:     PetscViewerSetType(v, PETSCVIEWERBINARY);
1403:     PetscViewerSetFromOptions(v);
1404:     PetscViewerFileSetMode(v, FILE_MODE_READ);
1405:     PetscViewerFileSetName(v, "datafile");
1406: .ve
1407:   The optional `PetscViewerSetFromOptions()` call allows overriding `PetscViewerSetType()` using the option
1408: .vb
1409:   -viewer_type (binary|hdf5)
1410: .ve

1412:   See the example src/ksp/ksp/tutorials/ex27.c with the first approach,
1413:   and src/mat/tutorials/ex10.c with the second approach.

1415:   In case of `PETSCVIEWERBINARY`, a native PETSc binary format is used. Each of the blocks
1416:   is read onto MPI rank 0 and then shipped to its destination MPI rank, one after another.
1417:   Multiple objects, both matrices and vectors, can be stored within the same file.
1418:   Their `PetscObject` name is ignored; they are loaded in the order of their storage.

1420:   Most users should not need to know the details of the binary storage
1421:   format, since `MatLoad()` and `MatView()` completely hide these details.
1422:   But for anyone who is interested, the standard binary matrix storage
1423:   format is

1425: .vb
1426:     PetscInt    MAT_FILE_CLASSID
1427:     PetscInt    number of rows
1428:     PetscInt    number of columns
1429:     PetscInt    total number of nonzeros
1430:     PetscInt    *number nonzeros in each row
1431:     PetscInt    *column indices of all nonzeros (starting index is zero)
1432:     PetscScalar *values of all nonzeros
1433: .ve
1434:   If PETSc was not configured with `--with-64-bit-indices` then only `MATMPIAIJ` matrices with more than `PETSC_INT_MAX` non-zeros can be
1435:   stored or loaded (each MPI process part of the matrix must have less than `PETSC_INT_MAX` nonzeros). Since the total nonzero count in this
1436:   case will not fit in a (32-bit) `PetscInt` the value `PETSC_INT_MAX` is used for the header entry `total number of nonzeros`.

1438:   PETSc automatically does the byte swapping for
1439:   machines that store the bytes reversed. Thus if you write your own binary
1440:   read/write routines you have to swap the bytes; see `PetscBinaryRead()`
1441:   and `PetscBinaryWrite()` to see how this may be done.

1443:   In case of `PETSCVIEWERHDF5`, a parallel HDF5 reader is used.
1444:   Each process's chunk is loaded independently by its owning MPI process.
1445:   Multiple objects, both matrices and vectors, can be stored within the same file.
1446:   They are looked up by their PetscObject name.

1448:   As the MATLAB MAT-File Version 7.3 format is also a HDF5 flavor, we decided to use
1449:   by default the same structure and naming of the AIJ arrays and column count
1450:   within the HDF5 file. This means that a MAT file saved with -v7.3 flag, e.g.
1451: .vb
1452:   save example.mat A b -v7.3
1453: .ve
1454:   can be directly read by this routine (see Reference 1 for details).

1456:   Depending on your MATLAB version, this format might be a default,
1457:   otherwise you can set it as default in Preferences.

1459:   Unless `-nocompression` flag is used to save the file in MATLAB,
1460:   PETSc must be configured with ZLIB package.

1462:   See also examples `src/mat/tutorials/ex10.c` and `src/ksp/ksp/tutorials/ex27.c`

1464:   This reader currently supports only real `MATSEQAIJ`, `MATMPIAIJ`, `MATSEQDENSE`, and `MATMPIDENSE` matrices for `PETSCVIEWERHDF5`

1466:   Corresponding `MatView()` is not yet implemented.

1468:   The loaded matrix is actually a transpose of the original one in MATLAB,
1469:   unless you push `PETSC_VIEWER_HDF5_MAT` format (see examples above).
1470:   With this format, matrix is automatically transposed by PETSc,
1471:   unless the matrix is marked as SPD or symmetric
1472:   (see `MatSetOption()`, `MAT_SPD`, `MAT_SYMMETRIC`).

1474:   See MATLAB Documentation on `save()`, <https://www.mathworks.com/help/matlab/ref/save.html#btox10b-1-version>

1476: .seealso: [](ch_matrices), `Mat`, `PetscViewerBinaryOpen()`, `PetscViewerSetType()`, `MatView()`, `VecLoad()`
1477:  @*/
1478: PetscErrorCode MatLoad(Mat mat, PetscViewer viewer)
1479: {
1480:   PetscBool flg;

1482:   PetscFunctionBegin;

1486:   if (!((PetscObject)mat)->type_name) PetscCall(MatSetType(mat, MATAIJ));

1488:   flg = PETSC_FALSE;
1489:   PetscCall(PetscOptionsGetBool(((PetscObject)mat)->options, ((PetscObject)mat)->prefix, "-matload_symmetric", &flg, NULL));
1490:   if (flg) {
1491:     PetscCall(MatSetOption(mat, MAT_SYMMETRIC, PETSC_TRUE));
1492:     PetscCall(MatSetOption(mat, MAT_SYMMETRY_ETERNAL, PETSC_TRUE));
1493:   }
1494:   flg = PETSC_FALSE;
1495:   PetscCall(PetscOptionsGetBool(((PetscObject)mat)->options, ((PetscObject)mat)->prefix, "-matload_spd", &flg, NULL));
1496:   if (flg) PetscCall(MatSetOption(mat, MAT_SPD, PETSC_TRUE));

1498:   PetscCall(PetscLogEventBegin(MAT_Load, mat, viewer, 0, 0));
1499:   PetscUseTypeMethod(mat, load, viewer);
1500:   PetscCall(PetscLogEventEnd(MAT_Load, mat, viewer, 0, 0));
1501:   PetscFunctionReturn(PETSC_SUCCESS);
1502: }

1504: static PetscErrorCode MatDestroy_Redundant(Mat_Redundant **redundant)
1505: {
1506:   Mat_Redundant *redund = *redundant;

1508:   PetscFunctionBegin;
1509:   if (redund) {
1510:     if (redund->matseq) { /* via MatCreateSubMatrices()  */
1511:       PetscCall(ISDestroy(&redund->isrow));
1512:       PetscCall(ISDestroy(&redund->iscol));
1513:       PetscCall(MatDestroySubMatrices(1, &redund->matseq));
1514:     } else {
1515:       PetscCall(PetscFree2(redund->send_rank, redund->recv_rank));
1516:       PetscCall(PetscFree(redund->sbuf_j));
1517:       PetscCall(PetscFree(redund->sbuf_a));
1518:       for (PetscInt i = 0; i < redund->nrecvs; i++) {
1519:         PetscCall(PetscFree(redund->rbuf_j[i]));
1520:         PetscCall(PetscFree(redund->rbuf_a[i]));
1521:       }
1522:       PetscCall(PetscFree4(redund->sbuf_nz, redund->rbuf_nz, redund->rbuf_j, redund->rbuf_a));
1523:     }

1525:     PetscCall(PetscCommDestroy(&redund->subcomm));
1526:     PetscCall(PetscFree(redund));
1527:   }
1528:   PetscFunctionReturn(PETSC_SUCCESS);
1529: }

1531: /*@
1532:   MatDestroy - Frees space taken by a matrix.

1534:   Collective

1536:   Input Parameter:
1537: . A - the matrix

1539:   Level: beginner

1541:   Developer Note:
1542:   Some special arrays of matrices are not destroyed in this routine but instead by the routines called by
1543:   `MatDestroySubMatrices()`. Thus one must be sure that any changes here must also be made in those routines.
1544:   `MatHeaderMerge()` and `MatHeaderReplace()` also manipulate the data in the `Mat` object and likely need changes
1545:   if changes are needed here.

1547: .seealso: [](ch_matrices), `Mat`, `MatCreate()`
1548: @*/
1549: PetscErrorCode MatDestroy(Mat *A)
1550: {
1551:   PetscFunctionBegin;
1552:   if (!*A) PetscFunctionReturn(PETSC_SUCCESS);
1554:   if (--((PetscObject)*A)->refct > 0) {
1555:     *A = NULL;
1556:     PetscFunctionReturn(PETSC_SUCCESS);
1557:   }

1559:   /* if memory was published with SAWs then destroy it */
1560:   PetscCall(PetscObjectSAWsViewOff((PetscObject)*A));
1561:   PetscTryTypeMethod(*A, destroy);

1563:   PetscCall(PetscFree((*A)->factorprefix));
1564:   PetscCall(PetscFree((*A)->defaultvectype));
1565:   PetscCall(PetscFree((*A)->defaultrandtype));
1566:   PetscCall(PetscFree((*A)->bsizes));
1567:   PetscCall(PetscFree((*A)->solvertype));
1568:   for (PetscInt i = 0; i < MAT_FACTOR_NUM_TYPES; i++) PetscCall(PetscFree((*A)->preferredordering[i]));
1569:   if ((*A)->redundant && (*A)->redundant->matseq[0] == *A) (*A)->redundant->matseq[0] = NULL;
1570:   PetscCall(MatDestroy_Redundant(&(*A)->redundant));
1571:   PetscCall(MatProductClear(*A));
1572:   PetscCall(MatNullSpaceDestroy(&(*A)->nullsp));
1573:   PetscCall(MatNullSpaceDestroy(&(*A)->transnullsp));
1574:   PetscCall(MatNullSpaceDestroy(&(*A)->nearnullsp));
1575:   PetscCall(MatDestroy(&(*A)->schur));
1576:   PetscCall(VecDestroy(&(*A)->dot_vec));
1577:   PetscCall(PetscLayoutDestroy(&(*A)->rmap));
1578:   PetscCall(PetscLayoutDestroy(&(*A)->cmap));
1579:   PetscCall(PetscHeaderDestroy(A));
1580:   PetscFunctionReturn(PETSC_SUCCESS);
1581: }

1583: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
1584: /*@
1585:   MatSetValues - Inserts or adds a block of values into a matrix.
1586:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
1587:   MUST be called after all calls to `MatSetValues()` have been completed.

1589:   Not Collective

1591:   Input Parameters:
1592: + mat  - the matrix
1593: . m    - the number of rows
1594: . idxm - the global indices of the rows
1595: . n    - the number of columns
1596: . idxn - the global indices of the columns
1597: . v    - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
1598:          See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.
1599: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

1601:   Level: beginner

1603:   Notes:
1604:   Calls to `MatSetValues()` with the `INSERT_VALUES` and `ADD_VALUES`
1605:   options cannot be mixed without intervening calls to the assembly
1606:   routines.

1608:   `MatSetValues()` uses 0-based row and column numbers in Fortran
1609:   as well as in C.

1611:   Negative indices may be passed in `idxm` and `idxn`, these rows and columns are simply ignored. This allows easily inserting element stiffness matrices
1612:   with homogeneous Dirichlet boundary conditions that you don't want represented
1613:   in the matrix.

1615:   Efficiency Alert:
1616:   The routine `MatSetValuesBlocked()` may offer much better efficiency
1617:   for users of block sparse formats (`MATSEQBAIJ` and `MATMPIBAIJ`).

1619:   Fortran Notes:
1620:   If any of `idxm`, `idxn`, and `v` are scalars pass them using, for example,
1621: .vb
1622:   call MatSetValues(mat, one, [idxm], one, [idxn], [v], INSERT_VALUES, ierr)
1623: .ve

1625:   If `v` is a two-dimensional array make sure to first call `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE, ierr)` before using this function,
1626:   otherwise the transpose of `v` will seemingly be inserted in the matrix, since Fortran passes two-dimensional arrays with column orientation.

1628: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1629:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`
1630: @*/
1631: PetscErrorCode MatSetValues(Mat mat, PetscInt m, const PetscInt idxm[], PetscInt n, const PetscInt idxn[], const PetscScalar v[], InsertMode addv)
1632: {
1633:   PetscFunctionBeginHot;
1636:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
1637:   PetscAssertPointer(idxm, 3);
1638:   PetscAssertPointer(idxn, 5);
1639:   MatCheckPreallocated(mat, 1);

1641:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
1642:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");

1644:   if (PetscDefined(USE_DEBUG)) {
1645:     PetscInt i, j;

1647:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
1648:     if (v) {
1649:       for (i = 0; i < m; i++) {
1650:         for (j = 0; j < n; j++) {
1651:           if (mat->erroriffailure && PetscIsInfOrNanScalar(v[i * n + j]))
1652: #if PetscDefined(USE_COMPLEX)
1653:             SETERRQ(PETSC_COMM_SELF, PETSC_ERR_FP, "Inserting %g+i%g at matrix entry (%" PetscInt_FMT ",%" PetscInt_FMT ")", (double)PetscRealPart(v[i * n + j]), (double)PetscImaginaryPart(v[i * n + j]), idxm[i], idxn[j]);
1654: #else
1655:             SETERRQ(PETSC_COMM_SELF, PETSC_ERR_FP, "Inserting %g at matrix entry (%" PetscInt_FMT ",%" PetscInt_FMT ")", (double)v[i * n + j], idxm[i], idxn[j]);
1656: #endif
1657:         }
1658:       }
1659:     }
1660:     for (i = 0; i < m; i++) PetscCheck(idxm[i] < mat->rmap->N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cannot insert in row %" PetscInt_FMT ", maximum is %" PetscInt_FMT, idxm[i], mat->rmap->N - 1);
1661:     for (i = 0; i < n; i++) PetscCheck(idxn[i] < mat->cmap->N, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Cannot insert in column %" PetscInt_FMT ", maximum is %" PetscInt_FMT, idxn[i], mat->cmap->N - 1);
1662:   }

1664:   if (mat->assembled) {
1665:     mat->was_assembled = PETSC_TRUE;
1666:     mat->assembled     = PETSC_FALSE;
1667:   }
1668:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
1669:   PetscUseTypeMethod(mat, setvalues, m, idxm, n, idxn, v, addv);
1670:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
1671:   PetscFunctionReturn(PETSC_SUCCESS);
1672: }

1674: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
1675: /*@
1676:   MatSetValuesIS - Inserts or adds a block of values into a matrix using an `IS` to indicate the rows and columns
1677:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
1678:   MUST be called after all calls to `MatSetValues()` have been completed.

1680:   Not Collective

1682:   Input Parameters:
1683: + mat  - the matrix
1684: . ism  - the rows to provide
1685: . isn  - the columns to provide
1686: . v    - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
1687:          See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.
1688: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

1690:   Level: beginner

1692:   Notes:
1693:   By default, the values, `v`, are stored in row-major order. See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.

1695:   Calls to `MatSetValues()` with the `INSERT_VALUES` and `ADD_VALUES`
1696:   options cannot be mixed without intervening calls to the assembly
1697:   routines.

1699:   `MatSetValues()` uses 0-based row and column numbers in Fortran
1700:   as well as in C.

1702:   Negative indices may be passed in `ism` and `isn`, these rows and columns are
1703:   simply ignored. This allows easily inserting element stiffness matrices
1704:   with homogeneous Dirichlet boundary conditions that you don't want represented
1705:   in the matrix.

1707:   Fortran Note:
1708:   If `v` is a two-dimensional array make sure to first call `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE, ierr)` before using this function,
1709:   otherwise the transpose of `v` will seemingly be inserted in the matrix, since Fortran passes two-dimensional arrays with column orientation.

1711:   Efficiency Alert:
1712:   The routine `MatSetValuesBlocked()` may offer much better efficiency
1713:   for users of block sparse formats (`MATSEQBAIJ` and `MATMPIBAIJ`).

1715:   This is currently not optimized for any particular `ISType`

1717: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatSetValues()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1718:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`
1719: @*/
1720: PetscErrorCode MatSetValuesIS(Mat mat, IS ism, IS isn, const PetscScalar v[], InsertMode addv)
1721: {
1722:   PetscInt        m, n;
1723:   const PetscInt *rows, *cols;

1725:   PetscFunctionBeginHot;
1727:   PetscCall(ISGetIndices(ism, &rows));
1728:   PetscCall(ISGetIndices(isn, &cols));
1729:   PetscCall(ISGetLocalSize(ism, &m));
1730:   PetscCall(ISGetLocalSize(isn, &n));
1731:   PetscCall(MatSetValues(mat, m, rows, n, cols, v, addv));
1732:   PetscCall(ISRestoreIndices(ism, &rows));
1733:   PetscCall(ISRestoreIndices(isn, &cols));
1734:   PetscFunctionReturn(PETSC_SUCCESS);
1735: }

1737: /*@
1738:   MatSetValuesRowLocal - Inserts a row of nonzero values into a matrix

1740:   Not Collective

1742:   Input Parameters:
1743: + mat - the matrix
1744: . row - the row to set
1745: - v   - a one-dimensional array that contains the values

1747:   Level: intermediate

1749:   Notes:
1750:   Currently only supported for `MATAIJ`.

1752:   All the nonzero values in `row` must be provided

1754:   The matrix must have previously had its column indices set, likely by having been assembled.

1756:   `row` must belong to this MPI process

1758: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1759:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`, `MatSetValues()`, `MatSetValuesRow()`, `MatSetLocalToGlobalMapping()`, `MATAIJ`
1760: @*/
1761: PetscErrorCode MatSetValuesRowLocal(Mat mat, PetscInt row, const PetscScalar v[])
1762: {
1763:   PetscInt globalrow;

1765:   PetscFunctionBegin;
1768:   PetscAssertPointer(v, 3);
1769:   PetscCall(ISLocalToGlobalMappingApply(mat->rmap->mapping, 1, &row, &globalrow));
1770:   PetscCall(MatSetValuesRow(mat, globalrow, v));
1771:   PetscFunctionReturn(PETSC_SUCCESS);
1772: }

1774: /*@
1775:   MatSetValuesRow - Inserts a row of nonzero values into a matrix

1777:   Not Collective

1779:   Input Parameters:
1780: + mat - the matrix
1781: . row - the row to set
1782: - v   - a one dimensional array of values

1784:   Level: advanced

1786:   Notes:
1787:   Currently only supported for `MATAIJ`.

1789:   All the nonzeros in `row` must be provided

1791:   The matrix must have previously had its column indices set, likely by having been assembled.

1793:   `row` must belong to this process

1795: .seealso: [](ch_matrices), `Mat`, `MatSetValues()`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1796:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`, `MATAIJ`
1797: @*/
1798: PetscErrorCode MatSetValuesRow(Mat mat, PetscInt row, const PetscScalar v[])
1799: {
1800:   PetscFunctionBeginHot;
1803:   MatCheckPreallocated(mat, 1);
1804:   PetscAssertPointer(v, 3);
1805:   PetscCheck(mat->insertmode != ADD_VALUES, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add and insert values");
1806:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
1807:   mat->insertmode = INSERT_VALUES;

1809:   if (mat->assembled) {
1810:     mat->was_assembled = PETSC_TRUE;
1811:     mat->assembled     = PETSC_FALSE;
1812:   }
1813:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
1814:   PetscUseTypeMethod(mat, setvaluesrow, row, v);
1815:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
1816:   PetscFunctionReturn(PETSC_SUCCESS);
1817: }

1819: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
1820: /*@
1821:   MatSetValuesStencil - Inserts or adds a block of values into a matrix.
1822:   Using structured grid indexing

1824:   Not Collective

1826:   Input Parameters:
1827: + mat  - the matrix
1828: . m    - number of rows being entered
1829: . idxm - grid coordinates (and component number when dof > 1) for matrix rows being entered
1830: . n    - number of columns being entered
1831: . idxn - grid coordinates (and component number when dof > 1) for matrix columns being entered
1832: . v    - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
1833:          See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.
1834: - addv - either `ADD_VALUES` to add to existing entries at that location or `INSERT_VALUES` to replace existing entries with new values

1836:   Level: beginner

1838:   Notes:
1839:   By default the values, `v`, are row-oriented. See `MatSetOption()` for other options.

1841:   Calls to `MatSetValuesStencil()` with the `INSERT_VALUES` and `ADD_VALUES`
1842:   options cannot be mixed without intervening calls to the assembly
1843:   routines.

1845:   The grid coordinates are across the entire grid, not just the local portion

1847:   `MatSetValuesStencil()` uses 0-based row and column numbers in Fortran
1848:   as well as in C.

1850:   For setting/accessing vector values via array coordinates you can use the `DMDAVecGetArray()` routine

1852:   In order to use this routine you must either obtain the matrix with `DMCreateMatrix()`
1853:   or call `MatSetLocalToGlobalMapping()` and `MatSetStencil()` first.

1855:   The columns and rows in the stencil passed in MUST be contained within the
1856:   ghost region of the given process as set with DMDACreateXXX() or `MatSetStencil()`. For example,
1857:   if you create a `DMDA` with an overlap of one grid level and on a particular process its first
1858:   local nonghost x logical coordinate is 6 (so its first ghost x logical coordinate is 5) the
1859:   first i index you can use in your column and row indices in `MatSetStencil()` is 5.

1861:   For periodic boundary conditions use negative indices for values to the left (below 0; that are to be
1862:   obtained by wrapping values from right edge). For values to the right of the last entry using that index plus one
1863:   etc to obtain values that obtained by wrapping the values from the left edge. This does not work for anything but the
1864:   `DM_BOUNDARY_PERIODIC` boundary type.

1866:   For indices that don't mean anything for your case (like the k index when working in 2d) or the c index when you have
1867:   a single value per point) you can skip filling those indices.

1869:   Inspired by the structured grid interface to the HYPRE package
1870:   (https://computation.llnl.gov/projects/hypre-scalable-linear-solvers-multigrid-methods)

1872:   Fortran Notes:
1873:   If any of `idxm`, `idxn`, and `v` are scalars pass them using, for example,
1874: .vb
1875:   call MatSetValuesStencil(mat, one, [idxm], one, [idxn], [v], INSERT_VALUES, ierr)
1876: .ve

1878:   If `v` is a two-dimensional array make sure to first call `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE, ierr)` before using this function,
1879:   otherwise the transpose of `v` will seemingly be inserted in the matrix, since Fortran passes two-dimensional arrays with column orientation.

1881:   Efficiency Alert:
1882:   The routine `MatSetValuesBlockedStencil()` may offer much better efficiency
1883:   for users of block sparse formats (`MATSEQBAIJ` and `MATMPIBAIJ`).

1885: .seealso: [](ch_matrices), `Mat`, `DMDA`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1886:           `MatSetValues()`, `MatSetValuesBlockedStencil()`, `MatSetStencil()`, `DMCreateMatrix()`, `DMDAVecGetArray()`, `MatStencil`
1887: @*/
1888: PetscErrorCode MatSetValuesStencil(Mat mat, PetscInt m, const MatStencil idxm[], PetscInt n, const MatStencil idxn[], const PetscScalar v[], InsertMode addv)
1889: {
1890:   PetscInt  buf[8192], *bufm = NULL, *bufn = NULL, *jdxm, *jdxn;
1891:   PetscInt  j, i, dim = mat->stencil.dim, *dims = mat->stencil.dims + 1, tmp;
1892:   PetscInt *starts = mat->stencil.starts, *dxm = (PetscInt *)idxm, *dxn = (PetscInt *)idxn, sdim = dim - (1 - (PetscInt)mat->stencil.noc);

1894:   PetscFunctionBegin;
1895:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
1898:   PetscAssertPointer(idxm, 3);
1899:   PetscAssertPointer(idxn, 5);

1901:   if ((m + n) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
1902:     jdxm = buf;
1903:     jdxn = buf + m;
1904:   } else {
1905:     PetscCall(PetscMalloc2(m, &bufm, n, &bufn));
1906:     jdxm = bufm;
1907:     jdxn = bufn;
1908:   }
1909:   for (i = 0; i < m; i++) {
1910:     for (j = 0; j < 3 - sdim; j++) dxm++;
1911:     tmp = *dxm++ - starts[0];
1912:     for (j = 0; j < dim - 1; j++) {
1913:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
1914:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
1915:     }
1916:     if (mat->stencil.noc) dxm++;
1917:     jdxm[i] = tmp;
1918:   }
1919:   for (i = 0; i < n; i++) {
1920:     for (j = 0; j < 3 - sdim; j++) dxn++;
1921:     tmp = *dxn++ - starts[0];
1922:     for (j = 0; j < dim - 1; j++) {
1923:       if ((*dxn++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
1924:       else tmp = tmp * dims[j] + *(dxn - 1) - starts[j + 1];
1925:     }
1926:     if (mat->stencil.noc) dxn++;
1927:     jdxn[i] = tmp;
1928:   }
1929:   PetscCall(MatSetValuesLocal(mat, m, jdxm, n, jdxn, v, addv));
1930:   PetscCall(PetscFree2(bufm, bufn));
1931:   PetscFunctionReturn(PETSC_SUCCESS);
1932: }

1934: /*@
1935:   MatSetValuesBlockedStencil - Inserts or adds a block of values into a matrix.
1936:   Using structured grid indexing

1938:   Not Collective

1940:   Input Parameters:
1941: + mat  - the matrix
1942: . m    - number of rows being entered
1943: . idxm - grid coordinates for matrix rows being entered
1944: . n    - number of columns being entered
1945: . idxn - grid coordinates for matrix columns being entered
1946: . v    - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
1947:          See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.
1948: - addv - either `ADD_VALUES` to add to existing entries or `INSERT_VALUES` to replace existing entries with new values

1950:   Level: beginner

1952:   Notes:
1953:   By default the values, `v`, are row-oriented and unsorted.
1954:   See `MatSetOption()` for other options.

1956:   Calls to `MatSetValuesBlockedStencil()` with the `INSERT_VALUES` and `ADD_VALUES`
1957:   options cannot be mixed without intervening calls to the assembly
1958:   routines.

1960:   The grid coordinates are across the entire grid, not just the local portion

1962:   `MatSetValuesBlockedStencil()` uses 0-based row and column numbers in Fortran
1963:   as well as in C.

1965:   For setting/accessing vector values via array coordinates you can use the `DMDAVecGetArray()` routine

1967:   In order to use this routine you must either obtain the matrix with `DMCreateMatrix()`
1968:   or call `MatSetBlockSize()`, `MatSetLocalToGlobalMapping()` and `MatSetStencil()` first.

1970:   The columns and rows in the stencil passed in MUST be contained within the
1971:   ghost region of the given process as set with DMDACreateXXX() or `MatSetStencil()`. For example,
1972:   if you create a `DMDA` with an overlap of one grid level and on a particular process its first
1973:   local nonghost x logical coordinate is 6 (so its first ghost x logical coordinate is 5) the
1974:   first i index you can use in your column and row indices in `MatSetStencil()` is 5.

1976:   Negative indices may be passed in `idxm` and `idxn`, these rows and columns are
1977:   simply ignored. This allows easily inserting element stiffness matrices
1978:   with homogeneous Dirichlet boundary conditions that you don't want represented
1979:   in the matrix.

1981:   Inspired by the structured grid interface to the HYPRE package
1982:   (https://computation.llnl.gov/projects/hypre-scalable-linear-solvers-multigrid-methods)

1984:   Fortran Notes:
1985:   If any of `idxm`, `idxn`, and `v` are scalars pass them using, for example,
1986: .vb
1987:   call MatSetValuesBlockedStencil(mat, one, [idxm], one, [idxn], [v], INSERT_VALUES, ierr)
1988: .ve

1990:   If `v` is a two-dimensional array make sure to first call `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE, ierr)` before using this function,
1991:   otherwise the transpose of `v` will seemingly be inserted in the matrix, since Fortran passes two-dimensional arrays with column orientation.

1993: .seealso: [](ch_matrices), `Mat`, `DMDA`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
1994:           `MatSetValues()`, `MatSetValuesStencil()`, `MatSetStencil()`, `DMCreateMatrix()`, `DMDAVecGetArray()`, `MatStencil`,
1995:           `MatSetBlockSize()`, `MatSetLocalToGlobalMapping()`
1996: @*/
1997: PetscErrorCode MatSetValuesBlockedStencil(Mat mat, PetscInt m, const MatStencil idxm[], PetscInt n, const MatStencil idxn[], const PetscScalar v[], InsertMode addv)
1998: {
1999:   PetscInt  buf[8192], *bufm = NULL, *bufn = NULL, *jdxm, *jdxn;
2000:   PetscInt  j, i, dim = mat->stencil.dim, *dims = mat->stencil.dims + 1, tmp;
2001:   PetscInt *starts = mat->stencil.starts, *dxm = (PetscInt *)idxm, *dxn = (PetscInt *)idxn, sdim = dim - (1 - (PetscInt)mat->stencil.noc);

2003:   PetscFunctionBegin;
2004:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
2007:   PetscAssertPointer(idxm, 3);
2008:   PetscAssertPointer(idxn, 5);
2009:   PetscAssertPointer(v, 6);

2011:   if ((m + n) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
2012:     jdxm = buf;
2013:     jdxn = buf + m;
2014:   } else {
2015:     PetscCall(PetscMalloc2(m, &bufm, n, &bufn));
2016:     jdxm = bufm;
2017:     jdxn = bufn;
2018:   }
2019:   for (i = 0; i < m; i++) {
2020:     for (j = 0; j < 3 - sdim; j++) dxm++;
2021:     tmp = *dxm++ - starts[0];
2022:     for (j = 0; j < sdim - 1; j++) {
2023:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
2024:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
2025:     }
2026:     dxm++;
2027:     jdxm[i] = tmp;
2028:   }
2029:   for (i = 0; i < n; i++) {
2030:     for (j = 0; j < 3 - sdim; j++) dxn++;
2031:     tmp = *dxn++ - starts[0];
2032:     for (j = 0; j < sdim - 1; j++) {
2033:       if ((*dxn++ - starts[j + 1]) < 0 || tmp < 0) tmp = -1;
2034:       else tmp = tmp * dims[j] + *(dxn - 1) - starts[j + 1];
2035:     }
2036:     dxn++;
2037:     jdxn[i] = tmp;
2038:   }
2039:   PetscCall(MatSetValuesBlockedLocal(mat, m, jdxm, n, jdxn, v, addv));
2040:   PetscCall(PetscFree2(bufm, bufn));
2041:   PetscFunctionReturn(PETSC_SUCCESS);
2042: }

2044: /*@
2045:   MatSetStencil - Sets the grid information for setting values into a matrix via
2046:   `MatSetValuesStencil()`

2048:   Not Collective

2050:   Input Parameters:
2051: + mat    - the matrix
2052: . dim    - dimension of the grid 1, 2, or 3
2053: . dims   - number of grid points in x, y, and z direction, including ghost points on your process
2054: . starts - starting point of ghost nodes on your process in x, y, and z direction
2055: - dof    - number of degrees of freedom per node

2057:   Level: beginner

2059:   Notes:
2060:   Inspired by the structured grid interface to the HYPRE package
2061:   (www.llnl.gov/CASC/hyper)

2063:   For matrices generated with `DMCreateMatrix()` this routine is automatically called and so not needed by the
2064:   user.

2066: .seealso: [](ch_matrices), `Mat`, `MatStencil`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
2067:           `MatSetValues()`, `MatSetValuesBlockedStencil()`, `MatSetValuesStencil()`
2068: @*/
2069: PetscErrorCode MatSetStencil(Mat mat, PetscInt dim, const PetscInt dims[], const PetscInt starts[], PetscInt dof)
2070: {
2071:   PetscFunctionBegin;
2073:   PetscAssertPointer(dims, 3);
2074:   PetscAssertPointer(starts, 4);

2076:   mat->stencil.dim = dim + (dof > 1);
2077:   for (PetscInt i = 0; i < dim; i++) {
2078:     mat->stencil.dims[i]   = dims[dim - i - 1]; /* copy the values in backwards */
2079:     mat->stencil.starts[i] = starts[dim - i - 1];
2080:   }
2081:   mat->stencil.dims[dim]   = dof;
2082:   mat->stencil.starts[dim] = 0;
2083:   mat->stencil.noc         = (PetscBool)(dof == 1);
2084:   PetscFunctionReturn(PETSC_SUCCESS);
2085: }

2087: /*@
2088:   MatSetValuesBlocked - Inserts or adds a block of values into a matrix.

2090:   Not Collective

2092:   Input Parameters:
2093: + mat  - the matrix
2094: . m    - the number of block rows
2095: . idxm - the global block indices
2096: . n    - the number of block columns
2097: . idxn - the global block indices
2098: . v    - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
2099:          See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.
2100: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` replaces existing entries with new values

2102:   Level: intermediate

2104:   Notes:
2105:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call
2106:   MatXXXXSetPreallocation() or `MatSetUp()` before using this routine.

2108:   The `m` and `n` count the NUMBER of blocks in the row direction and column direction,
2109:   NOT the total number of rows/columns; for example, if the block size is 2 and
2110:   you are passing in values for rows 2,3,4,5  then `m` would be 2 (not 4).
2111:   The values in `idxm` would be 1 2; that is the first index for each block divided by
2112:   the block size.

2114:   You must call `MatSetBlockSize()` when constructing this matrix (before
2115:   preallocating it).

2117:   By default, the values, `v`, are stored in row-major order. See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.

2119:   Calls to `MatSetValuesBlocked()` with the `INSERT_VALUES` and `ADD_VALUES`
2120:   options cannot be mixed without intervening calls to the assembly
2121:   routines.

2123:   `MatSetValuesBlocked()` uses 0-based row and column numbers in Fortran
2124:   as well as in C.

2126:   Negative indices may be passed in `idxm` and `idxn`, these rows and columns are
2127:   simply ignored. This allows easily inserting element stiffness matrices
2128:   with homogeneous Dirichlet boundary conditions that you don't want represented
2129:   in the matrix.

2131:   Each time an entry is set within a sparse matrix via `MatSetValues()`,
2132:   internal searching must be done to determine where to place the
2133:   data in the matrix storage space. By instead inserting blocks of
2134:   entries via `MatSetValuesBlocked()`, the overhead of matrix assembly is
2135:   reduced.

2137:   Example:
2138: .vb
2139:    Suppose m=n=2 and block size(bs) = 2 The array is

2141:    1  2  | 3  4
2142:    5  6  | 7  8
2143:    - - - | - - -
2144:    9  10 | 11 12
2145:    13 14 | 15 16

2147:    v[] should be passed in like
2148:    v[] = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16]

2150:   If you are not using row-oriented storage of v (that is you called MatSetOption(mat,MAT_ROW_ORIENTED,PETSC_FALSE)) then
2151:    v[] = [1,5,9,13,2,6,10,14,3,7,11,15,4,8,12,16]
2152: .ve

2154:   Fortran Notes:
2155:   If any of `idmx`, `idxn`, and `v` are scalars pass them using, for example,
2156: .vb
2157:   call MatSetValuesBlocked(mat, one, [idxm], one, [idxn], [v], INSERT_VALUES, ierr)
2158: .ve

2160:   If `v` is a two-dimensional array make sure to first call `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE, ierr)` before using this function,
2161:   otherwise the transpose of `v` will seemingly be inserted in the matrix, since Fortran passes two-dimensional arrays with column orientation.

2163: .seealso: [](ch_matrices), `Mat`, `MatSetBlockSize()`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetValuesBlockedLocal()`
2164: @*/
2165: PetscErrorCode MatSetValuesBlocked(Mat mat, PetscInt m, const PetscInt idxm[], PetscInt n, const PetscInt idxn[], const PetscScalar v[], InsertMode addv)
2166: {
2167:   PetscFunctionBeginHot;
2170:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
2171:   PetscAssertPointer(idxm, 3);
2172:   PetscAssertPointer(idxn, 5);
2173:   MatCheckPreallocated(mat, 1);
2174:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
2175:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");
2176:   if (PetscDefined(USE_DEBUG)) {
2177:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2178:     PetscCheck(mat->ops->setvaluesblocked || mat->ops->setvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2179:   }
2180:   if (PetscDefined(USE_DEBUG)) {
2181:     PetscInt rbs, cbs, M, N, i;
2182:     PetscCall(MatGetBlockSizes(mat, &rbs, &cbs));
2183:     PetscCall(MatGetSize(mat, &M, &N));
2184:     for (i = 0; i < m; i++) PetscCheck(idxm[i] * rbs < M, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Row block %" PetscInt_FMT " contains an index %" PetscInt_FMT "*%" PetscInt_FMT " greater than row length %" PetscInt_FMT, i, idxm[i], rbs, M);
2185:     for (i = 0; i < n; i++)
2186:       PetscCheck(idxn[i] * cbs < N, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Column block %" PetscInt_FMT " contains an index %" PetscInt_FMT "*%" PetscInt_FMT " greater than column length %" PetscInt_FMT, i, idxn[i], cbs, N);
2187:   }
2188:   if (mat->assembled) {
2189:     mat->was_assembled = PETSC_TRUE;
2190:     mat->assembled     = PETSC_FALSE;
2191:   }
2192:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
2193:   if (mat->ops->setvaluesblocked) PetscUseTypeMethod(mat, setvaluesblocked, m, idxm, n, idxn, v, addv);
2194:   else {
2195:     PetscInt buf[8192], *bufr = NULL, *bufc = NULL, *iidxm, *iidxn;
2196:     PetscInt i, j, bs, cbs;

2198:     PetscCall(MatGetBlockSizes(mat, &bs, &cbs));
2199:     if ((m * bs + n * cbs) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
2200:       iidxm = buf;
2201:       iidxn = buf + m * bs;
2202:     } else {
2203:       PetscCall(PetscMalloc2(m * bs, &bufr, n * cbs, &bufc));
2204:       iidxm = bufr;
2205:       iidxn = bufc;
2206:     }
2207:     for (i = 0; i < m; i++) {
2208:       for (j = 0; j < bs; j++) iidxm[i * bs + j] = bs * idxm[i] + j;
2209:     }
2210:     if (m != n || bs != cbs || idxm != idxn) {
2211:       for (i = 0; i < n; i++) {
2212:         for (j = 0; j < cbs; j++) iidxn[i * cbs + j] = cbs * idxn[i] + j;
2213:       }
2214:     } else iidxn = iidxm;
2215:     PetscCall(MatSetValues(mat, m * bs, iidxm, n * cbs, iidxn, v, addv));
2216:     PetscCall(PetscFree2(bufr, bufc));
2217:   }
2218:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
2219:   PetscFunctionReturn(PETSC_SUCCESS);
2220: }

2222: /*@
2223:   MatGetValues - Gets a block of local values from a matrix.

2225:   Not Collective; can only return values that are owned by the give process

2227:   Input Parameters:
2228: + mat  - the matrix
2229: . v    - a logically two-dimensional array for storing the values
2230: . m    - the number of rows
2231: . idxm - the  global indices of the rows
2232: . n    - the number of columns
2233: - idxn - the global indices of the columns

2235:   Level: advanced

2237:   Notes:
2238:   The user must allocate space (m*n `PetscScalar`s) for the values, `v`.

2240:   The values, `v`, are returned in a row-oriented format, analogous to that used by default in `MatSetValues()`,
2241:   unless `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE)` is called in which case they are returned column oriented.

2243:   `MatGetValues()` uses 0-based row and column numbers in
2244:   Fortran as well as in C.

2246:   For `MATSBAIJ` matrices only the block upper triangular entries will be set.

2248:   `MatGetValues()` requires that the matrix has been assembled
2249:   with `MatAssemblyBegin()`/`MatAssemblyEnd()`. Thus, calls to
2250:   `MatSetValues()` and `MatGetValues()` CANNOT be made in succession
2251:   without intermediate matrix assembly.

2253:   Negative row or column indices will be ignored and those locations in `v` will be
2254:   left unchanged.

2256:   For the standard row-based matrix formats, `idxm` can only contain rows owned by the requesting MPI process.
2257:   That is, rows with global index greater than or equal to `rstart` and less than `rend` where `rstart` and `rend` are obtainable
2258:   from `MatGetOwnershipRange`(mat,&rstart,&rend).

2260: .seealso: [](ch_matrices), `Mat`, `MatGetRow()`, `MatCreateSubMatrices()`, `MatSetValues()`, `MatGetOwnershipRange()`, `MatGetValuesLocal()`, `MatGetValue()`
2261: @*/
2262: PetscErrorCode MatGetValues(Mat mat, PetscInt m, const PetscInt idxm[], PetscInt n, const PetscInt idxn[], PetscScalar v[])
2263: {
2264:   PetscFunctionBegin;
2267:   if (!m || !n) PetscFunctionReturn(PETSC_SUCCESS);
2268:   PetscAssertPointer(idxm, 3);
2269:   PetscAssertPointer(idxn, 5);
2270:   PetscAssertPointer(v, 6);
2271:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2272:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2273:   MatCheckPreallocated(mat, 1);

2275:   PetscCall(PetscLogEventBegin(MAT_GetValues, mat, 0, 0, 0));
2276:   PetscUseTypeMethod(mat, getvalues, m, idxm, n, idxn, v);
2277:   PetscCall(PetscLogEventEnd(MAT_GetValues, mat, 0, 0, 0));
2278:   PetscFunctionReturn(PETSC_SUCCESS);
2279: }

2281: /*@
2282:   MatGetValuesLocal - retrieves values from certain locations in a matrix using the local numbering of the indices
2283:   defined previously by `MatSetLocalToGlobalMapping()`

2285:   Not Collective

2287:   Input Parameters:
2288: + mat  - the matrix
2289: . nrow - number of rows
2290: . irow - the row local indices
2291: . ncol - number of columns
2292: - icol - the column local indices

2294:   Output Parameter:
2295: . y - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
2296:       See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.

2298:   Level: advanced

2300:   Notes:
2301:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call `MatSetLocalToGlobalMapping()` before using this routine.

2303:   This routine can only return values that are owned by the requesting MPI process. That is, for standard matrix formats, rows that, in the global numbering,
2304:   are greater than or equal to rstart and less than rend where rstart and rend are obtainable from `MatGetOwnershipRange`(mat,&rstart,&rend). One can
2305:   determine if the resulting global row associated with the local row r is owned by the requesting MPI process by applying the `ISLocalToGlobalMapping` set
2306:   with `MatSetLocalToGlobalMapping()`.

2308: .seealso: [](ch_matrices), `Mat`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetLocalToGlobalMapping()`,
2309:           `MatSetValuesLocal()`, `MatGetValues()`
2310: @*/
2311: PetscErrorCode MatGetValuesLocal(Mat mat, PetscInt nrow, const PetscInt irow[], PetscInt ncol, const PetscInt icol[], PetscScalar y[])
2312: {
2313:   PetscFunctionBeginHot;
2316:   MatCheckPreallocated(mat, 1);
2317:   if (!nrow || !ncol) PetscFunctionReturn(PETSC_SUCCESS); /* no values to retrieve */
2318:   PetscAssertPointer(irow, 3);
2319:   PetscAssertPointer(icol, 5);
2320:   if (PetscDefined(USE_DEBUG)) {
2321:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2322:     PetscCheck(mat->ops->getvalueslocal || mat->ops->getvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2323:   }
2324:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2325:   PetscCall(PetscLogEventBegin(MAT_GetValues, mat, 0, 0, 0));
2326:   if (mat->ops->getvalueslocal) PetscUseTypeMethod(mat, getvalueslocal, nrow, irow, ncol, icol, y);
2327:   else {
2328:     PetscInt buf[8192], *bufr = NULL, *bufc = NULL, *irowm, *icolm;
2329:     if ((nrow + ncol) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
2330:       irowm = buf;
2331:       icolm = buf + nrow;
2332:     } else {
2333:       PetscCall(PetscMalloc2(nrow, &bufr, ncol, &bufc));
2334:       irowm = bufr;
2335:       icolm = bufc;
2336:     }
2337:     PetscCheck(mat->rmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MatGetValuesLocal() cannot proceed without local-to-global row mapping (See MatSetLocalToGlobalMapping()).");
2338:     PetscCheck(mat->cmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MatGetValuesLocal() cannot proceed without local-to-global column mapping (See MatSetLocalToGlobalMapping()).");
2339:     PetscCall(ISLocalToGlobalMappingApply(mat->rmap->mapping, nrow, irow, irowm));
2340:     PetscCall(ISLocalToGlobalMappingApply(mat->cmap->mapping, ncol, icol, icolm));
2341:     PetscCall(MatGetValues(mat, nrow, irowm, ncol, icolm, y));
2342:     PetscCall(PetscFree2(bufr, bufc));
2343:   }
2344:   PetscCall(PetscLogEventEnd(MAT_GetValues, mat, 0, 0, 0));
2345:   PetscFunctionReturn(PETSC_SUCCESS);
2346: }

2348: /*@
2349:   MatSetValuesBatch - Adds (`ADD_VALUES`) many blocks of values into a matrix at once. The blocks must all be square and
2350:   the same size. Currently, this can only be called once and creates the given matrix.

2352:   Not Collective

2354:   Input Parameters:
2355: + mat  - the matrix
2356: . nb   - the number of blocks
2357: . bs   - the number of rows (and columns) in each block
2358: . rows - a concatenation of the rows for each block
2359: - v    - a concatenation of logically two-dimensional arrays of values

2361:   Level: advanced

2363:   Notes:
2364:   `MatSetPreallocationCOO()` and `MatSetValuesCOO()` may be a better way to provide the values

2366:   In the future, we will extend this routine to handle rectangular blocks, and to allow multiple calls for a given matrix.

2368: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValuesBlocked()`, `MatSetValuesLocal()`,
2369:           `InsertMode`, `INSERT_VALUES`, `ADD_VALUES`, `MatSetValues()`, `MatSetPreallocationCOO()`, `MatSetValuesCOO()`
2370: @*/
2371: PetscErrorCode MatSetValuesBatch(Mat mat, PetscInt nb, PetscInt bs, PetscInt rows[], const PetscScalar v[])
2372: {
2373:   PetscFunctionBegin;
2376:   PetscAssertPointer(rows, 4);
2377:   PetscAssertPointer(v, 5);
2378:   PetscAssert(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

2380:   PetscCall(PetscLogEventBegin(MAT_SetValuesBatch, mat, 0, 0, 0));
2381:   for (PetscInt b = 0; b < nb; ++b) PetscCall(MatSetValues(mat, bs, &rows[b * bs], bs, &rows[b * bs], &v[b * bs * bs], ADD_VALUES));
2382:   PetscCall(PetscLogEventEnd(MAT_SetValuesBatch, mat, 0, 0, 0));
2383:   PetscFunctionReturn(PETSC_SUCCESS);
2384: }

2386: /*@
2387:   MatSetLocalToGlobalMapping - Sets a local-to-global numbering for use by
2388:   the routine `MatSetValuesLocal()` to allow users to insert matrix entries
2389:   using a local (per-process) numbering.

2391:   Not Collective

2393:   Input Parameters:
2394: + x        - the matrix
2395: . rmapping - row mapping created with `ISLocalToGlobalMappingCreate()` or `ISLocalToGlobalMappingCreateIS()`
2396: - cmapping - column mapping

2398:   Level: intermediate

2400:   Note:
2401:   If the matrix is obtained with `DMCreateMatrix()` then this may already have been called on the matrix

2403: .seealso: [](ch_matrices), `Mat`, `DM`, `DMCreateMatrix()`, `MatGetLocalToGlobalMapping()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetValuesLocal()`, `MatGetValuesLocal()`
2404: @*/
2405: PetscErrorCode MatSetLocalToGlobalMapping(Mat x, ISLocalToGlobalMapping rmapping, ISLocalToGlobalMapping cmapping)
2406: {
2407:   PetscFunctionBegin;
2412:   if (x->ops->setlocaltoglobalmapping) PetscUseTypeMethod(x, setlocaltoglobalmapping, rmapping, cmapping);
2413:   else {
2414:     PetscCall(PetscLayoutSetISLocalToGlobalMapping(x->rmap, rmapping));
2415:     PetscCall(PetscLayoutSetISLocalToGlobalMapping(x->cmap, cmapping));
2416:   }
2417:   PetscFunctionReturn(PETSC_SUCCESS);
2418: }

2420: /*@
2421:   MatGetLocalToGlobalMapping - Gets the local-to-global numbering set by `MatSetLocalToGlobalMapping()`

2423:   Not Collective

2425:   Input Parameter:
2426: . A - the matrix

2428:   Output Parameters:
2429: + rmapping - row mapping
2430: - cmapping - column mapping

2432:   Level: advanced

2434: .seealso: [](ch_matrices), `Mat`, `MatSetLocalToGlobalMapping()`, `MatSetValuesLocal()`
2435: @*/
2436: PetscErrorCode MatGetLocalToGlobalMapping(Mat A, ISLocalToGlobalMapping *rmapping, ISLocalToGlobalMapping *cmapping)
2437: {
2438:   PetscFunctionBegin;
2441:   if (rmapping) {
2442:     PetscAssertPointer(rmapping, 2);
2443:     *rmapping = A->rmap->mapping;
2444:   }
2445:   if (cmapping) {
2446:     PetscAssertPointer(cmapping, 3);
2447:     *cmapping = A->cmap->mapping;
2448:   }
2449:   PetscFunctionReturn(PETSC_SUCCESS);
2450: }

2452: /*@
2453:   MatSetLayouts - Sets the `PetscLayout` objects for rows and columns of a matrix

2455:   Logically Collective

2457:   Input Parameters:
2458: + A    - the matrix
2459: . rmap - row layout
2460: - cmap - column layout

2462:   Level: advanced

2464:   Note:
2465:   The `PetscLayout` objects are usually created automatically for the matrix so this routine rarely needs to be called.

2467: .seealso: [](ch_matrices), `Mat`, `PetscLayout`, `MatCreateVecs()`, `MatGetLocalToGlobalMapping()`, `MatGetLayouts()`
2468: @*/
2469: PetscErrorCode MatSetLayouts(Mat A, PetscLayout rmap, PetscLayout cmap)
2470: {
2471:   PetscFunctionBegin;
2473:   PetscCall(PetscLayoutReference(rmap, &A->rmap));
2474:   PetscCall(PetscLayoutReference(cmap, &A->cmap));
2475:   PetscFunctionReturn(PETSC_SUCCESS);
2476: }

2478: /*@
2479:   MatGetLayouts - Gets the `PetscLayout` objects for rows and columns

2481:   Not Collective

2483:   Input Parameter:
2484: . A - the matrix

2486:   Output Parameters:
2487: + rmap - row layout
2488: - cmap - column layout

2490:   Level: advanced

2492: .seealso: [](ch_matrices), `Mat`, [Matrix Layouts](sec_matlayout), `PetscLayout`, `MatCreateVecs()`, `MatGetLocalToGlobalMapping()`, `MatSetLayouts()`
2493: @*/
2494: PetscErrorCode MatGetLayouts(Mat A, PetscLayout *rmap, PetscLayout *cmap)
2495: {
2496:   PetscFunctionBegin;
2499:   if (rmap) {
2500:     PetscAssertPointer(rmap, 2);
2501:     *rmap = A->rmap;
2502:   }
2503:   if (cmap) {
2504:     PetscAssertPointer(cmap, 3);
2505:     *cmap = A->cmap;
2506:   }
2507:   PetscFunctionReturn(PETSC_SUCCESS);
2508: }

2510: /*@
2511:   MatSetValuesLocal - Inserts or adds values into certain locations of a matrix,
2512:   using a local numbering of the rows and columns.

2514:   Not Collective

2516:   Input Parameters:
2517: + mat  - the matrix
2518: . nrow - number of rows
2519: . irow - the row local indices
2520: . ncol - number of columns
2521: . icol - the column local indices
2522: . v    - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
2523:          See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.
2524: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

2526:   Level: intermediate

2528:   Notes:
2529:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call `MatSetLocalToGlobalMapping()` before using this routine

2531:   Calls to `MatSetValuesLocal()` with the `INSERT_VALUES` and `ADD_VALUES`
2532:   options cannot be mixed without intervening calls to the assembly
2533:   routines.

2535:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
2536:   MUST be called after all calls to `MatSetValuesLocal()` have been completed.

2538:   Fortran Notes:
2539:   If any of `irow`, `icol`, and `v` are scalars pass them using, for example,
2540: .vb
2541:   call MatSetValuesLocal(mat, one, [irow], one, [icol], [v], INSERT_VALUES, ierr)
2542: .ve

2544:   If `v` is a two-dimensional array make sure to first call `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE, ierr)` before using this function,
2545:   otherwise the transpose of `v` will seemingly be inserted in the matrix, since Fortran passes two-dimensional arrays with column orientation.

2547: .seealso: [](ch_matrices), `Mat`, `MatAssemblyBegin()`, `MatAssemblyEnd()`, `MatSetValues()`, `MatSetLocalToGlobalMapping()`,
2548:           `MatGetValuesLocal()`
2549: @*/
2550: PetscErrorCode MatSetValuesLocal(Mat mat, PetscInt nrow, const PetscInt irow[], PetscInt ncol, const PetscInt icol[], const PetscScalar v[], InsertMode addv)
2551: {
2552:   PetscFunctionBeginHot;
2555:   MatCheckPreallocated(mat, 1);
2556:   if (!nrow || !ncol) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
2557:   PetscAssertPointer(irow, 3);
2558:   PetscAssertPointer(icol, 5);
2559:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
2560:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");
2561:   if (PetscDefined(USE_DEBUG)) {
2562:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2563:     PetscCheck(mat->ops->setvalueslocal || mat->ops->setvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2564:   }

2566:   if (mat->assembled) {
2567:     mat->was_assembled = PETSC_TRUE;
2568:     mat->assembled     = PETSC_FALSE;
2569:   }
2570:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
2571:   if (mat->ops->setvalueslocal) PetscUseTypeMethod(mat, setvalueslocal, nrow, irow, ncol, icol, v, addv);
2572:   else {
2573:     PetscInt        buf[8192], *bufr = NULL, *bufc = NULL;
2574:     const PetscInt *irowm, *icolm;

2576:     if ((!mat->rmap->mapping && !mat->cmap->mapping) || (nrow + ncol) <= (PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf)) {
2577:       bufr  = buf;
2578:       bufc  = buf + nrow;
2579:       irowm = bufr;
2580:       icolm = bufc;
2581:     } else {
2582:       PetscCall(PetscMalloc2(nrow, &bufr, ncol, &bufc));
2583:       irowm = bufr;
2584:       icolm = bufc;
2585:     }
2586:     if (mat->rmap->mapping) PetscCall(ISLocalToGlobalMappingApply(mat->rmap->mapping, nrow, irow, bufr));
2587:     else irowm = irow;
2588:     if (mat->cmap->mapping) {
2589:       if (mat->cmap->mapping != mat->rmap->mapping || ncol != nrow || icol != irow) PetscCall(ISLocalToGlobalMappingApply(mat->cmap->mapping, ncol, icol, bufc));
2590:       else icolm = irowm;
2591:     } else icolm = icol;
2592:     PetscCall(MatSetValues(mat, nrow, irowm, ncol, icolm, v, addv));
2593:     if (bufr != buf) PetscCall(PetscFree2(bufr, bufc));
2594:   }
2595:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
2596:   PetscFunctionReturn(PETSC_SUCCESS);
2597: }

2599: /*@
2600:   MatSetValuesBlockedLocal - Inserts or adds values into certain locations of a matrix,
2601:   using a local ordering of the nodes a block at a time.

2603:   Not Collective

2605:   Input Parameters:
2606: + mat  - the matrix
2607: . nrow - number of rows
2608: . irow - the row local indices
2609: . ncol - number of columns
2610: . icol - the column local indices
2611: . v    - a one-dimensional array that contains the values implicitly stored as a two-dimensional array, by default in row-major order.
2612:          See `MAT_ROW_ORIENTED` in `MatSetOption()` for how to use column-major order.
2613: - addv - either `ADD_VALUES` to add values to any existing entries, or `INSERT_VALUES` to replace existing entries with new values

2615:   Level: intermediate

2617:   Notes:
2618:   If you create the matrix yourself (that is not with a call to `DMCreateMatrix()`) then you MUST call `MatSetBlockSize()` and `MatSetLocalToGlobalMapping()`
2619:   before using this routineBefore calling `MatSetValuesLocal()`, the user must first set the

2621:   Calls to `MatSetValuesBlockedLocal()` with the `INSERT_VALUES` and `ADD_VALUES`
2622:   options cannot be mixed without intervening calls to the assembly
2623:   routines.

2625:   These values may be cached, so `MatAssemblyBegin()` and `MatAssemblyEnd()`
2626:   MUST be called after all calls to `MatSetValuesBlockedLocal()` have been completed.

2628:   Fortran Notes:
2629:   If any of `irow`, `icol`, and `v` are scalars pass them using, for example,
2630: .vb
2631:   call MatSetValuesBlockedLocal(mat, one, [irow], one, [icol], [v], INSERT_VALUES, ierr)
2632: .ve

2634:   If `v` is a two-dimensional array make sure to first call `MatSetOption(mat, MAT_ROW_ORIENTED, PETSC_FALSE, ierr)` before using this function,
2635:   otherwise the transpose of `v` will seemingly be inserted in the matrix, since Fortran passes two-dimensional arrays with column orientation.

2637: .seealso: [](ch_matrices), `Mat`, `MatSetBlockSize()`, `MatSetLocalToGlobalMapping()`, `MatAssemblyBegin()`, `MatAssemblyEnd()`,
2638:           `MatSetValuesLocal()`, `MatSetValuesBlocked()`
2639: @*/
2640: PetscErrorCode MatSetValuesBlockedLocal(Mat mat, PetscInt nrow, const PetscInt irow[], PetscInt ncol, const PetscInt icol[], const PetscScalar v[], InsertMode addv)
2641: {
2642:   PetscFunctionBeginHot;
2645:   MatCheckPreallocated(mat, 1);
2646:   if (!nrow || !ncol) PetscFunctionReturn(PETSC_SUCCESS); /* no values to insert */
2647:   PetscAssertPointer(irow, 3);
2648:   PetscAssertPointer(icol, 5);
2649:   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
2650:   else PetscCheck(mat->insertmode == addv, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Cannot mix add values and insert values");
2651:   if (PetscDefined(USE_DEBUG)) {
2652:     PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2653:     PetscCheck(mat->ops->setvaluesblockedlocal || mat->ops->setvaluesblocked || mat->ops->setvalueslocal || mat->ops->setvalues, PETSC_COMM_SELF, PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2654:   }

2656:   if (mat->assembled) {
2657:     mat->was_assembled = PETSC_TRUE;
2658:     mat->assembled     = PETSC_FALSE;
2659:   }
2660:   if (PetscUnlikelyDebug(mat->rmap->mapping)) { /* Condition on the mapping existing, because MatSetValuesBlockedLocal_IS does not require it to be set. */
2661:     PetscInt irbs, rbs;
2662:     PetscCall(MatGetBlockSizes(mat, &rbs, NULL));
2663:     PetscCall(ISLocalToGlobalMappingGetBlockSize(mat->rmap->mapping, &irbs));
2664:     PetscCheck(rbs == irbs, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Different row block sizes! mat %" PetscInt_FMT ", row l2g map %" PetscInt_FMT, rbs, irbs);
2665:   }
2666:   if (PetscUnlikelyDebug(mat->cmap->mapping)) {
2667:     PetscInt icbs, cbs;
2668:     PetscCall(MatGetBlockSizes(mat, NULL, &cbs));
2669:     PetscCall(ISLocalToGlobalMappingGetBlockSize(mat->cmap->mapping, &icbs));
2670:     PetscCheck(cbs == icbs, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Different col block sizes! mat %" PetscInt_FMT ", col l2g map %" PetscInt_FMT, cbs, icbs);
2671:   }
2672:   PetscCall(PetscLogEventBegin(MAT_SetValues, mat, 0, 0, 0));
2673:   if (mat->ops->setvaluesblockedlocal) PetscUseTypeMethod(mat, setvaluesblockedlocal, nrow, irow, ncol, icol, v, addv);
2674:   else {
2675:     PetscInt        buf[8192], *bufr = NULL, *bufc = NULL;
2676:     const PetscInt *irowm, *icolm;

2678:     if ((!mat->rmap->mapping && !mat->cmap->mapping) || (nrow + ncol) <= ((PetscInt)PETSC_STATIC_ARRAY_LENGTH(buf))) {
2679:       bufr  = buf;
2680:       bufc  = buf + nrow;
2681:       irowm = bufr;
2682:       icolm = bufc;
2683:     } else {
2684:       PetscCall(PetscMalloc2(nrow, &bufr, ncol, &bufc));
2685:       irowm = bufr;
2686:       icolm = bufc;
2687:     }
2688:     if (mat->rmap->mapping) PetscCall(ISLocalToGlobalMappingApplyBlock(mat->rmap->mapping, nrow, irow, bufr));
2689:     else irowm = irow;
2690:     if (mat->cmap->mapping) {
2691:       if (mat->cmap->mapping != mat->rmap->mapping || ncol != nrow || icol != irow) PetscCall(ISLocalToGlobalMappingApplyBlock(mat->cmap->mapping, ncol, icol, bufc));
2692:       else icolm = irowm;
2693:     } else icolm = icol;
2694:     PetscCall(MatSetValuesBlocked(mat, nrow, irowm, ncol, icolm, v, addv));
2695:     if (bufr != buf) PetscCall(PetscFree2(bufr, bufc));
2696:   }
2697:   PetscCall(PetscLogEventEnd(MAT_SetValues, mat, 0, 0, 0));
2698:   PetscFunctionReturn(PETSC_SUCCESS);
2699: }

2701: /*@
2702:   MatMultDiagonalBlock - Computes the matrix-vector product, $y = Dx$. Where `D` is defined by the inode or block structure of the diagonal

2704:   Collective

2706:   Input Parameters:
2707: + mat - the matrix
2708: - x   - the vector to be multiplied

2710:   Output Parameter:
2711: . y - the result

2713:   Level: developer

2715:   Note:
2716:   The vectors `x` and `y` cannot be the same. I.e., one cannot
2717:   call `MatMultDiagonalBlock`(A,y,y).

2719: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
2720: @*/
2721: PetscErrorCode MatMultDiagonalBlock(Mat mat, Vec x, Vec y)
2722: {
2723:   PetscFunctionBegin;

2729:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2730:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2731:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2732:   MatCheckPreallocated(mat, 1);

2734:   PetscUseTypeMethod(mat, multdiagonalblock, x, y);
2735:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
2736:   PetscFunctionReturn(PETSC_SUCCESS);
2737: }

2739: /*@
2740:   MatMult - Computes the matrix-vector product, $y = Ax$.

2742:   Neighbor-wise Collective

2744:   Input Parameters:
2745: + mat - the matrix
2746: - x   - the vector to be multiplied

2748:   Output Parameter:
2749: . y - the result

2751:   Level: beginner

2753:   Note:
2754:   The vectors `x` and `y` cannot be the same. I.e., one cannot
2755:   call `MatMult`(A,y,y).

2757: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
2758: @*/
2759: PetscErrorCode MatMult(Mat mat, Vec x, Vec y)
2760: {
2761:   PetscFunctionBegin;
2765:   VecCheckAssembled(x);
2767:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2768:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2769:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2770:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
2771:   PetscCheck(mat->rmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, y->map->N);
2772:   PetscCheck(mat->cmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, x->map->n);
2773:   PetscCheck(mat->rmap->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, y->map->n);
2774:   PetscCall(VecSetErrorIfLocked(y, 3));
2775:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2776:   MatCheckPreallocated(mat, 1);

2778:   PetscCall(VecLockReadPush(x));
2779:   PetscCall(PetscLogEventBegin(MAT_Mult, mat, x, y, 0));
2780:   PetscUseTypeMethod(mat, mult, x, y);
2781:   PetscCall(PetscLogEventEnd(MAT_Mult, mat, x, y, 0));
2782:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(y, 3, PETSC_FALSE));
2783:   PetscCall(VecLockReadPop(x));
2784:   PetscFunctionReturn(PETSC_SUCCESS);
2785: }

2787: /*@
2788:   MatMultTranspose - Computes matrix transpose times a vector $y = A^T x$.

2790:   Neighbor-wise Collective

2792:   Input Parameters:
2793: + mat - the matrix
2794: - x   - the vector to be multiplied

2796:   Output Parameter:
2797: . y - the result

2799:   Level: beginner

2801:   Notes:
2802:   The vectors `x` and `y` cannot be the same. I.e., one cannot
2803:   call `MatMultTranspose`(A,y,y).

2805:   For complex numbers this does NOT compute the Hermitian (complex conjugate) transpose multiple,
2806:   use `MatMultHermitianTranspose()`

2808: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatMultHermitianTranspose()`, `MatTranspose()`
2809: @*/
2810: PetscErrorCode MatMultTranspose(Mat mat, Vec x, Vec y)
2811: {
2812:   PetscErrorCode (*op)(Mat, Vec, Vec) = NULL;

2814:   PetscFunctionBegin;
2818:   VecCheckAssembled(x);

2821:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2822:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2823:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2824:   PetscCheck(mat->cmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, y->map->N);
2825:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
2826:   PetscCheck(mat->cmap->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, y->map->n);
2827:   PetscCheck(mat->rmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, x->map->n);
2828:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2829:   MatCheckPreallocated(mat, 1);

2831:   if (!mat->ops->multtranspose) {
2832:     if (mat->symmetric == PETSC_BOOL3_TRUE && mat->ops->mult) op = mat->ops->mult;
2833:     PetscCheck(op, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Matrix type %s does not have a multiply transpose defined or is symmetric and does not have a multiply defined", ((PetscObject)mat)->type_name);
2834:   } else op = mat->ops->multtranspose;
2835:   PetscCall(PetscLogEventBegin(MAT_MultTranspose, mat, x, y, 0));
2836:   PetscCall(VecLockReadPush(x));
2837:   PetscCall((*op)(mat, x, y));
2838:   PetscCall(VecLockReadPop(x));
2839:   PetscCall(PetscLogEventEnd(MAT_MultTranspose, mat, x, y, 0));
2840:   PetscCall(PetscObjectStateIncrease((PetscObject)y));
2841:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(y, 3, PETSC_FALSE));
2842:   PetscFunctionReturn(PETSC_SUCCESS);
2843: }

2845: /*@
2846:   MatMultHermitianTranspose - Computes matrix Hermitian-transpose times a vector $y = A^H x$.

2848:   Neighbor-wise Collective

2850:   Input Parameters:
2851: + mat - the matrix
2852: - x   - the vector to be multiplied

2854:   Output Parameter:
2855: . y - the result

2857:   Level: beginner

2859:   Notes:
2860:   The vectors `x` and `y` cannot be the same. I.e., one cannot
2861:   call `MatMultHermitianTranspose`(A,y,y).

2863:   Also called the conjugate transpose, complex conjugate transpose, or adjoint.

2865:   For real numbers `MatMultTranspose()` and `MatMultHermitianTranspose()` are identical.

2867: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultAdd()`, `MatMultHermitianTransposeAdd()`, `MatMultTranspose()`
2868: @*/
2869: PetscErrorCode MatMultHermitianTranspose(Mat mat, Vec x, Vec y)
2870: {
2871:   PetscFunctionBegin;

2877:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2878:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2879:   PetscCheck(x != y, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "x and y must be different vectors");
2880:   PetscCheck(mat->cmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, y->map->N);
2881:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
2882:   PetscCheck(mat->cmap->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, y->map->n);
2883:   PetscCheck(mat->rmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, x->map->n);
2884:   MatCheckPreallocated(mat, 1);

2886:   PetscCall(PetscLogEventBegin(MAT_MultHermitianTranspose, mat, x, y, 0));
2887:   if (PetscDefined(USE_COMPLEX)) {
2888:     if (mat->ops->multhermitiantranspose || (mat->hermitian == PETSC_BOOL3_TRUE && mat->ops->mult)) {
2889:       PetscCall(VecLockReadPush(x));
2890:       if (mat->ops->multhermitiantranspose) PetscUseTypeMethod(mat, multhermitiantranspose, x, y);
2891:       else PetscUseTypeMethod(mat, mult, x, y);
2892:       PetscCall(VecLockReadPop(x));
2893:     } else {
2894:       Vec w;
2895:       PetscCall(VecDuplicate(x, &w));
2896:       PetscCall(VecCopy(x, w));
2897:       PetscCall(VecConjugate(w));
2898:       PetscCall(MatMultTranspose(mat, w, y));
2899:       PetscCall(VecDestroy(&w));
2900:       PetscCall(VecConjugate(y));
2901:     }
2902:     PetscCall(PetscObjectStateIncrease((PetscObject)y));
2903:   } else PetscCall(MatMultTranspose(mat, x, y));
2904:   PetscCall(PetscLogEventEnd(MAT_MultHermitianTranspose, mat, x, y, 0));
2905:   PetscFunctionReturn(PETSC_SUCCESS);
2906: }

2908: /*@
2909:   MatMultAdd -  Computes $v3 = v2 + A v1$.

2911:   Neighbor-wise Collective

2913:   Input Parameters:
2914: + mat - the matrix
2915: . v1  - the vector to be multiplied by `mat`
2916: - v2  - the vector to be added to the result

2918:   Output Parameter:
2919: . v3 - the result

2921:   Level: beginner

2923:   Note:
2924:   The vectors `v1` and `v3` cannot be the same. I.e., one cannot
2925:   call `MatMultAdd`(A,v1,v2,v1).

2927: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMult()`, `MatMultTransposeAdd()`
2928: @*/
2929: PetscErrorCode MatMultAdd(Mat mat, Vec v1, Vec v2, Vec v3)
2930: {
2931:   PetscFunctionBegin;

2938:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2939:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2940:   PetscCheck(mat->cmap->N == v1->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v1: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v1->map->N);
2941:   /* PetscCheck(mat->rmap->N == v2->map->N,PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Mat mat,Vec v2: global dim %" PetscInt_FMT " %" PetscInt_FMT,mat->rmap->N,v2->map->N);
2942:      PetscCheck(mat->rmap->N == v3->map->N,PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Mat mat,Vec v3: global dim %" PetscInt_FMT " %" PetscInt_FMT,mat->rmap->N,v3->map->N); */
2943:   PetscCheck(mat->rmap->n == v3->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec v3: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, v3->map->n);
2944:   PetscCheck(mat->rmap->n == v2->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec v2: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, v2->map->n);
2945:   PetscCheck(v1 != v3, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "v1 and v3 must be different vectors");
2946:   MatCheckPreallocated(mat, 1);

2948:   PetscCall(PetscLogEventBegin(MAT_MultAdd, mat, v1, v2, v3));
2949:   PetscCall(VecLockReadPush(v1));
2950:   PetscUseTypeMethod(mat, multadd, v1, v2, v3);
2951:   PetscCall(VecLockReadPop(v1));
2952:   PetscCall(PetscLogEventEnd(MAT_MultAdd, mat, v1, v2, v3));
2953:   PetscCall(PetscObjectStateIncrease((PetscObject)v3));
2954:   PetscFunctionReturn(PETSC_SUCCESS);
2955: }

2957: /*@
2958:   MatMultTransposeAdd - Computes $v3 = v2 + A^T v1$.

2960:   Neighbor-wise Collective

2962:   Input Parameters:
2963: + mat - the matrix
2964: . v1  - the vector to be multiplied by the transpose of the matrix
2965: - v2  - the vector to be added to the result

2967:   Output Parameter:
2968: . v3 - the result

2970:   Level: beginner

2972:   Note:
2973:   The vectors `v1` and `v3` cannot be the same. I.e., one cannot
2974:   call `MatMultTransposeAdd`(A,v1,v2,v1).

2976: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMult()`
2977: @*/
2978: PetscErrorCode MatMultTransposeAdd(Mat mat, Vec v1, Vec v2, Vec v3)
2979: {
2980:   PetscErrorCode (*op)(Mat, Vec, Vec, Vec) = (!mat->ops->multtransposeadd && mat->symmetric) ? mat->ops->multadd : mat->ops->multtransposeadd;

2982:   PetscFunctionBegin;

2989:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
2990:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
2991:   PetscCheck(mat->rmap->N == v1->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v1: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, v1->map->N);
2992:   PetscCheck(mat->cmap->N == v2->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v2: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v2->map->N);
2993:   PetscCheck(mat->cmap->N == v3->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v3: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v3->map->N);
2994:   PetscCheck(v1 != v3, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "v1 and v3 must be different vectors");
2995:   PetscCheck(op, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Mat type %s", ((PetscObject)mat)->type_name);
2996:   MatCheckPreallocated(mat, 1);

2998:   PetscCall(PetscLogEventBegin(MAT_MultTransposeAdd, mat, v1, v2, v3));
2999:   PetscCall(VecLockReadPush(v1));
3000:   PetscCall((*op)(mat, v1, v2, v3));
3001:   PetscCall(VecLockReadPop(v1));
3002:   PetscCall(PetscLogEventEnd(MAT_MultTransposeAdd, mat, v1, v2, v3));
3003:   PetscCall(PetscObjectStateIncrease((PetscObject)v3));
3004:   PetscFunctionReturn(PETSC_SUCCESS);
3005: }

3007: /*@
3008:   MatMultHermitianTransposeAdd - Computes $v3 = v2 + A^H v1$.

3010:   Neighbor-wise Collective

3012:   Input Parameters:
3013: + mat - the matrix
3014: . v1  - the vector to be multiplied by the Hermitian transpose
3015: - v2  - the vector to be added to the result

3017:   Output Parameter:
3018: . v3 - the result

3020:   Level: beginner

3022:   Note:
3023:   The vectors `v1` and `v3` cannot be the same. I.e., one cannot
3024:   call `MatMultHermitianTransposeAdd`(A,v1,v2,v1).

3026: .seealso: [](ch_matrices), `Mat`, `MatMultHermitianTranspose()`, `MatMultTranspose()`, `MatMultAdd()`, `MatMult()`
3027: @*/
3028: PetscErrorCode MatMultHermitianTransposeAdd(Mat mat, Vec v1, Vec v2, Vec v3)
3029: {
3030:   PetscFunctionBegin;

3037:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3038:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3039:   PetscCheck(v1 != v3, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "v1 and v3 must be different vectors");
3040:   PetscCheck(mat->rmap->N == v1->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v1: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, v1->map->N);
3041:   PetscCheck(mat->cmap->N == v2->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v2: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v2->map->N);
3042:   PetscCheck(mat->cmap->N == v3->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec v3: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, v3->map->N);
3043:   MatCheckPreallocated(mat, 1);

3045:   PetscCall(PetscLogEventBegin(MAT_MultHermitianTransposeAdd, mat, v1, v2, v3));
3046:   PetscCall(VecLockReadPush(v1));
3047:   if (mat->ops->multhermitiantransposeadd) PetscUseTypeMethod(mat, multhermitiantransposeadd, v1, v2, v3);
3048:   else {
3049:     Vec w, z;
3050:     PetscCall(VecDuplicate(v1, &w));
3051:     PetscCall(VecCopy(v1, w));
3052:     PetscCall(VecConjugate(w));
3053:     PetscCall(VecDuplicate(v3, &z));
3054:     PetscCall(MatMultTranspose(mat, w, z));
3055:     PetscCall(VecDestroy(&w));
3056:     PetscCall(VecConjugate(z));
3057:     if (v2 != v3) PetscCall(VecWAXPY(v3, 1.0, v2, z));
3058:     else PetscCall(VecAXPY(v3, 1.0, z));
3059:     PetscCall(VecDestroy(&z));
3060:   }
3061:   PetscCall(VecLockReadPop(v1));
3062:   PetscCall(PetscLogEventEnd(MAT_MultHermitianTransposeAdd, mat, v1, v2, v3));
3063:   PetscCall(PetscObjectStateIncrease((PetscObject)v3));
3064:   PetscFunctionReturn(PETSC_SUCCESS);
3065: }

3067: static PetscErrorCode MatADot_Default(Mat mat, Vec x, Vec y, PetscScalar *val)
3068: {
3069:   PetscFunctionBegin;
3070:   if (!mat->dot_vec) PetscCall(MatCreateVecs(mat, NULL, &mat->dot_vec));
3071:   PetscCall(MatMult(mat, x, mat->dot_vec));
3072:   PetscCall(VecDot(mat->dot_vec, y, val));
3073:   PetscFunctionReturn(PETSC_SUCCESS);
3074: }

3076: static PetscErrorCode MatANorm_Default(Mat mat, Vec x, PetscReal *val)
3077: {
3078:   PetscScalar sval;

3080:   PetscFunctionBegin;
3081:   PetscCall(MatADot(mat, x, x, &sval));
3082:   PetscCheck(PetscRealPart(sval) >= 0.0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "Matrix argument is not positive definite");
3083:   PetscCheck(PetscAbsReal(PetscImaginaryPart(sval)) <= 100 * PETSC_MACHINE_EPSILON * PetscMax(1.0, PetscAbsScalar(sval)), PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "Matrix argument is not Hermitian");
3084:   *val = PetscSqrtReal(PetscRealPart(sval));
3085:   PetscFunctionReturn(PETSC_SUCCESS);
3086: }

3088: /*@
3089:   MatADot - Computes the inner product with respect to a matrix, i.e., $(x, y)_A = y^H A x$ where $A$ is symmetric (Hermitian when using complex)
3090:   positive definite.

3092:   Collective

3094:   Input Parameters:
3095: + mat - matrix used to define the inner product
3096: . x   - first vector
3097: - y   - second vector

3099:   Output Parameter:
3100: . val - the dot product with respect to `A`

3102:   Level: intermediate

3104:   Note:
3105:   For complex vectors, `MatADot()` computes
3106: $$
3107:   val = (x,y)_A = y^H A x,
3108: $$
3109:   where $y^H$ denotes the conjugate transpose of `y`. Note that this corresponds to the "mathematicians" complex
3110:   inner product where the SECOND argument gets the complex conjugate.

3112: .seealso: [](ch_matrices), `Mat`, `MatANorm()`, `VecDot()`, `VecNorm()`, `MatMult()`, `MatMultAdd()`, `MatMultTransposeAdd()`
3113: @*/
3114: PetscErrorCode MatADot(Mat mat, Vec x, Vec y, PetscScalar *val)
3115: {
3116:   PetscFunctionBegin;
3120:   VecCheckAssembled(x);
3122:   VecCheckAssembled(y);
3125:   PetscAssertPointer(val, 4);
3126:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3127:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3128:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
3129:   PetscCheck(mat->rmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, y->map->N);
3130:   PetscCheck(mat->cmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, x->map->n);
3131:   PetscCheck(mat->rmap->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, y->map->n);
3132:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
3133:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(y, 3, PETSC_TRUE));
3134:   MatCheckPreallocated(mat, 1);

3136:   PetscCall(VecLockReadPush(x));
3137:   PetscCall(VecLockReadPush(y));
3138:   PetscCall(PetscLogEventBegin(MAT_ADot, mat, x, y, 0));
3139:   if (mat->ops->adot) PetscUseTypeMethod(mat, adot, x, y, val);
3140:   else PetscCall(MatADot_Default(mat, x, y, val));
3141:   PetscCall(PetscLogEventEnd(MAT_ADot, mat, x, y, 0));
3142:   PetscCall(VecLockReadPop(y));
3143:   PetscCall(VecLockReadPop(x));
3144:   PetscFunctionReturn(PETSC_SUCCESS);
3145: }

3147: /*@
3148:   MatANorm - Computes the norm with respect to a matrix, i.e., $(x, x)_A^{1/2} = (x^H A x)^{1/2}$ where $A$ is symmetric (Hermitian when using complex)
3149:   positive definite.

3151:   Collective

3153:   Input Parameters:
3154: + mat - matrix used to define norm
3155: - x   - the vector to compute the norm of

3157:   Output Parameter:
3158: . val - the norm with respect to `A`

3160:   Level: intermediate

3162:   Note:
3163:   For complex vectors, `MatANorm()` computes
3164: $$
3165:   val = (x,x)_A^{1/2} = (x^H A x)^{1/2},
3166: $$
3167:   where $x^H$ denotes the conjugate transpose of `x`.

3169: .seealso: [](ch_matrices), `Mat`, `MatADot()`, `VecDot()`, `VecNorm()`, `MatMult()`, `MatMultAdd()`, `MatMultTransposeAdd()`
3170: @*/
3171: PetscErrorCode MatANorm(Mat mat, Vec x, PetscReal *val)
3172: {
3173:   PetscFunctionBegin;
3177:   VecCheckAssembled(x);
3179:   PetscAssertPointer(val, 3);
3180:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3181:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3182:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
3183:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
3184:   PetscCheck(mat->cmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->n, x->map->n);
3185:   PetscCheck(mat->rmap->n == x->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, x->map->n);
3186:   if (mat->erroriffailure) PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
3187:   MatCheckPreallocated(mat, 1);

3189:   PetscCall(VecLockReadPush(x));
3190:   PetscCall(PetscLogEventBegin(MAT_ANorm, mat, x, 0, 0));
3191:   if (mat->ops->anorm) PetscUseTypeMethod(mat, anorm, x, val);
3192:   else PetscCall(MatANorm_Default(mat, x, val));
3193:   PetscCall(PetscLogEventEnd(MAT_ANorm, mat, x, 0, 0));
3194:   PetscCall(VecLockReadPop(x));
3195:   PetscFunctionReturn(PETSC_SUCCESS);
3196: }

3198: /*@
3199:   MatGetFactorType - gets the type of factorization a matrix is

3201:   Not Collective

3203:   Input Parameter:
3204: . mat - the matrix

3206:   Output Parameter:
3207: . t - the type, one of `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`, `MAT_FACTOR_ICC,MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`

3209:   Level: intermediate

3211: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorType`, `MatGetFactor()`, `MatSetFactorType()`, `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`,
3212:           `MAT_FACTOR_ICC`, `MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`
3213: @*/
3214: PetscErrorCode MatGetFactorType(Mat mat, MatFactorType *t)
3215: {
3216:   PetscFunctionBegin;
3219:   PetscAssertPointer(t, 2);
3220:   *t = mat->factortype;
3221:   PetscFunctionReturn(PETSC_SUCCESS);
3222: }

3224: /*@
3225:   MatSetFactorType - sets the type of factorization a matrix is

3227:   Logically Collective

3229:   Input Parameters:
3230: + mat - the matrix
3231: - t   - the type, one of `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`, `MAT_FACTOR_ICC,MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`

3233:   Level: intermediate

3235: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorType`, `MatGetFactor()`, `MatGetFactorType()`, `MAT_FACTOR_NONE`, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ILU`,
3236:           `MAT_FACTOR_ICC`, `MAT_FACTOR_ILUDT`, `MAT_FACTOR_QR`
3237: @*/
3238: PetscErrorCode MatSetFactorType(Mat mat, MatFactorType t)
3239: {
3240:   PetscFunctionBegin;
3243:   mat->factortype = t;
3244:   PetscFunctionReturn(PETSC_SUCCESS);
3245: }

3247: /*@
3248:   MatGetInfo - Returns information about matrix storage (number of
3249:   nonzeros, memory, etc.).

3251:   Collective if `MAT_GLOBAL_MAX` or `MAT_GLOBAL_SUM` is used as the flag

3253:   Input Parameters:
3254: + mat  - the matrix
3255: - flag - flag indicating the type of parameters to be returned (`MAT_LOCAL` - local matrix, `MAT_GLOBAL_MAX` - maximum over all processes, `MAT_GLOBAL_SUM` - sum over all processes)

3257:   Output Parameter:
3258: . info - matrix information context

3260:   Options Database Key:
3261: . -mat_view :[filename]:ascii_info - print the matrix information to `filename` or `stdout`, see `MatView()`

3263:   Level: intermediate

3265:   Notes:
3266:   The `MatInfo` context contains a variety of matrix data, including
3267:   number of nonzeros allocated and used, number of mallocs during
3268:   matrix assembly, etc. Additional information for factored matrices
3269:   is provided (such as the fill ratio, number of mallocs during
3270:   factorization, etc.).

3272:   Example:
3273:   See the file `${PETSC_DIR}/include/petscmat.h` for a complete list of
3274:   data within the `MatInfo` context.  For example,
3275: .vb
3276:       MatInfo info;
3277:       Mat     A;
3278:       double  mal, nz_a, nz_u;

3280:       MatGetInfo(A, MAT_LOCAL, &info);
3281:       mal  = info.mallocs;
3282:       nz_a = info.nz_allocated;
3283: .ve

3285: .seealso: [](ch_matrices), `Mat`, `MatInfo`, `MatStashGetInfo()`
3286: @*/
3287: PetscErrorCode MatGetInfo(Mat mat, MatInfoType flag, MatInfo *info)
3288: {
3289:   PetscFunctionBegin;
3292:   PetscAssertPointer(info, 3);
3293:   MatCheckPreallocated(mat, 1);
3294:   PetscUseTypeMethod(mat, getinfo, flag, info);
3295:   PetscFunctionReturn(PETSC_SUCCESS);
3296: }

3298: /*
3299:    This is used by external packages where it is not easy to get the info from the actual
3300:    matrix factorization.
3301: */
3302: PetscErrorCode MatGetInfo_External(Mat A, MatInfoType flag, MatInfo *info)
3303: {
3304:   PetscFunctionBegin;
3305:   PetscCall(PetscMemzero(info, sizeof(MatInfo)));
3306:   PetscFunctionReturn(PETSC_SUCCESS);
3307: }

3309: /*@
3310:   MatLUFactor - Performs in-place LU factorization of matrix.

3312:   Collective

3314:   Input Parameters:
3315: + mat  - the matrix
3316: . row  - row permutation
3317: . col  - column permutation
3318: - info - options for factorization, includes
3319: .vb
3320:           fill - expected fill as ratio of original fill.
3321:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3322:                    Run with the option -info to determine an optimal value to use
3323: .ve

3325:   Level: developer

3327:   Notes:
3328:   Most users should employ the `KSP` interface for linear solvers
3329:   instead of working directly with matrix algebra routines such as this.
3330:   See, e.g., `KSPCreate()`.

3332:   This changes the state of the matrix to a factored matrix; it cannot be used
3333:   for example with `MatSetValues()` unless one first calls `MatSetUnfactored()`.

3335:   This is really in-place only for dense matrices, the preferred approach is to use `MatGetFactor()`, `MatLUFactorSymbolic()`, and `MatLUFactorNumeric()`
3336:   when not using `KSP`.

3338:   Fortran Note:
3339:   A valid (non-null) `info` argument must be provided

3341: .seealso: [](ch_matrices), [Matrix Factorization](sec_matfactor), `Mat`, `MatFactorType`, `MatLUFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`,
3342:           `MatGetOrdering()`, `MatSetUnfactored()`, `MatFactorInfo`, `MatGetFactor()`
3343: @*/
3344: PetscErrorCode MatLUFactor(Mat mat, IS row, IS col, const MatFactorInfo *info)
3345: {
3346:   MatFactorInfo tinfo;

3348:   PetscFunctionBegin;
3352:   if (info) PetscAssertPointer(info, 4);
3354:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3355:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3356:   MatCheckPreallocated(mat, 1);
3357:   if (!info) {
3358:     PetscCall(MatFactorInfoInitialize(&tinfo));
3359:     info = &tinfo;
3360:   }

3362:   PetscCall(PetscLogEventBegin(MAT_LUFactor, mat, row, col, 0));
3363:   PetscUseTypeMethod(mat, lufactor, row, col, info);
3364:   PetscCall(PetscLogEventEnd(MAT_LUFactor, mat, row, col, 0));
3365:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3366:   PetscFunctionReturn(PETSC_SUCCESS);
3367: }

3369: /*@
3370:   MatILUFactor - Performs in-place ILU factorization of matrix.

3372:   Collective

3374:   Input Parameters:
3375: + mat  - the matrix
3376: . row  - row permutation
3377: . col  - column permutation
3378: - info - structure containing
3379: .vb
3380:       levels - number of levels of fill.
3381:       expected fill - as ratio of original fill.
3382:       1 or 0 - indicating force fill on diagonal (improves robustness for matrices
3383:                 missing diagonal entries)
3384: .ve

3386:   Level: developer

3388:   Notes:
3389:   Most users should employ the `KSP` interface for linear solvers
3390:   instead of working directly with matrix algebra routines such as this.
3391:   See, e.g., `KSPCreate()`.

3393:   Probably really in-place only when level of fill is zero, otherwise allocates
3394:   new space to store factored matrix and deletes previous memory. The preferred approach is to use `MatGetFactor()`, `MatILUFactorSymbolic()`, and `MatLUFactorNumeric()`
3395:   when not using `KSP`.

3397:   Fortran Note:
3398:   A valid (non-null) `info` argument must be provided

3400: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatILUFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`, `MatFactorInfo`
3401: @*/
3402: PetscErrorCode MatILUFactor(Mat mat, IS row, IS col, const MatFactorInfo *info)
3403: {
3404:   PetscFunctionBegin;
3408:   PetscAssertPointer(info, 4);
3410:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "matrix must be square");
3411:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3412:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3413:   MatCheckPreallocated(mat, 1);

3415:   PetscCall(PetscLogEventBegin(MAT_ILUFactor, mat, row, col, 0));
3416:   PetscUseTypeMethod(mat, ilufactor, row, col, info);
3417:   PetscCall(PetscLogEventEnd(MAT_ILUFactor, mat, row, col, 0));
3418:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3419:   PetscFunctionReturn(PETSC_SUCCESS);
3420: }

3422: /*@
3423:   MatLUFactorSymbolic - Performs symbolic LU factorization of matrix.
3424:   Call this routine before calling `MatLUFactorNumeric()` and after `MatGetFactor()`.

3426:   Collective

3428:   Input Parameters:
3429: + fact - the factor matrix obtained with `MatGetFactor()`
3430: . mat  - the matrix
3431: . row  - the row permutation
3432: . col  - the column permutation
3433: - info - options for factorization, includes
3434: .vb
3435:           fill - expected fill as ratio of original fill. Run with the option -info to determine an optimal value to use
3436:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3437: .ve

3439:   Level: developer

3441:   Notes:
3442:   See [Matrix Factorization](sec_matfactor) for additional information about factorizations

3444:   Most users should employ the simplified `KSP` interface for linear solvers
3445:   instead of working directly with matrix algebra routines such as this.
3446:   See, e.g., `KSPCreate()`.

3448:   Fortran Note:
3449:   A valid (non-null) `info` argument must be provided

3451: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatLUFactor()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`, `MatFactorInfo`, `MatFactorInfoInitialize()`
3452: @*/
3453: PetscErrorCode MatLUFactorSymbolic(Mat fact, Mat mat, IS row, IS col, const MatFactorInfo *info)
3454: {
3455:   MatFactorInfo tinfo;

3457:   PetscFunctionBegin;
3462:   if (info) PetscAssertPointer(info, 5);
3465:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3466:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3467:   MatCheckPreallocated(mat, 2);
3468:   if (!info) {
3469:     PetscCall(MatFactorInfoInitialize(&tinfo));
3470:     info = &tinfo;
3471:   }

3473:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_LUFactorSymbolic, mat, row, col, 0));
3474:   PetscUseTypeMethod(fact, lufactorsymbolic, mat, row, col, info);
3475:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_LUFactorSymbolic, mat, row, col, 0));
3476:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3477:   PetscFunctionReturn(PETSC_SUCCESS);
3478: }

3480: /*@
3481:   MatLUFactorNumeric - Performs numeric LU factorization of a matrix.
3482:   Call this routine after first calling `MatLUFactorSymbolic()` and `MatGetFactor()`.

3484:   Collective

3486:   Input Parameters:
3487: + fact - the factor matrix obtained with `MatGetFactor()`
3488: . mat  - the matrix
3489: - info - options for factorization

3491:   Level: developer

3493:   Notes:
3494:   See `MatLUFactor()` for in-place factorization. See
3495:   `MatCholeskyFactorNumeric()` for the symmetric, positive definite case.

3497:   Most users should employ the `KSP` interface for linear solvers
3498:   instead of working directly with matrix algebra routines such as this.
3499:   See, e.g., `KSPCreate()`.

3501:   Fortran Note:
3502:   A valid (non-null) `info` argument must be provided

3504: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatFactorInfo`, `MatLUFactorSymbolic()`, `MatLUFactor()`, `MatCholeskyFactor()`
3505: @*/
3506: PetscErrorCode MatLUFactorNumeric(Mat fact, Mat mat, const MatFactorInfo *info)
3507: {
3508:   MatFactorInfo tinfo;

3510:   PetscFunctionBegin;
3515:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3516:   PetscCheck(mat->rmap->N == (fact)->rmap->N && mat->cmap->N == (fact)->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Mat fact: global dimensions are different %" PetscInt_FMT " should = %" PetscInt_FMT " %" PetscInt_FMT " should = %" PetscInt_FMT,
3517:              mat->rmap->N, (fact)->rmap->N, mat->cmap->N, (fact)->cmap->N);

3519:   MatCheckPreallocated(mat, 2);
3520:   if (!info) {
3521:     PetscCall(MatFactorInfoInitialize(&tinfo));
3522:     info = &tinfo;
3523:   }

3525:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_LUFactorNumeric, mat, fact, 0, 0));
3526:   else PetscCall(PetscLogEventBegin(MAT_LUFactor, mat, fact, 0, 0));
3527:   PetscUseTypeMethod(fact, lufactornumeric, mat, info);
3528:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_LUFactorNumeric, mat, fact, 0, 0));
3529:   else PetscCall(PetscLogEventEnd(MAT_LUFactor, mat, fact, 0, 0));
3530:   PetscCall(MatViewFromOptions(fact, NULL, "-mat_factor_view"));
3531:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3532:   PetscFunctionReturn(PETSC_SUCCESS);
3533: }

3535: /*@
3536:   MatCholeskyFactor - Performs in-place Cholesky factorization of a
3537:   symmetric matrix.

3539:   Collective

3541:   Input Parameters:
3542: + mat  - the matrix
3543: . perm - row and column permutations
3544: - info - expected fill as ratio of original fill

3546:   Level: developer

3548:   Notes:
3549:   See `MatLUFactor()` for the nonsymmetric case. See also `MatGetFactor()`,
3550:   `MatCholeskyFactorSymbolic()`, and `MatCholeskyFactorNumeric()`.

3552:   Most users should employ the `KSP` interface for linear solvers
3553:   instead of working directly with matrix algebra routines such as this.
3554:   See, e.g., `KSPCreate()`.

3556:   Fortran Note:
3557:   A valid (non-null) `info` argument must be provided

3559: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatFactorInfo`, `MatLUFactor()`, `MatCholeskyFactorSymbolic()`, `MatCholeskyFactorNumeric()`,
3560:           `MatGetOrdering()`
3561: @*/
3562: PetscErrorCode MatCholeskyFactor(Mat mat, IS perm, const MatFactorInfo *info)
3563: {
3564:   MatFactorInfo tinfo;

3566:   PetscFunctionBegin;
3569:   if (info) PetscAssertPointer(info, 3);
3571:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "Matrix must be square");
3572:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3573:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3574:   MatCheckPreallocated(mat, 1);
3575:   if (!info) {
3576:     PetscCall(MatFactorInfoInitialize(&tinfo));
3577:     info = &tinfo;
3578:   }

3580:   PetscCall(PetscLogEventBegin(MAT_CholeskyFactor, mat, perm, 0, 0));
3581:   PetscUseTypeMethod(mat, choleskyfactor, perm, info);
3582:   PetscCall(PetscLogEventEnd(MAT_CholeskyFactor, mat, perm, 0, 0));
3583:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3584:   PetscFunctionReturn(PETSC_SUCCESS);
3585: }

3587: /*@
3588:   MatCholeskyFactorSymbolic - Performs symbolic Cholesky factorization
3589:   of a symmetric matrix.

3591:   Collective

3593:   Input Parameters:
3594: + fact - the factor matrix obtained with `MatGetFactor()`
3595: . mat  - the matrix
3596: . perm - row and column permutations
3597: - info - options for factorization, includes
3598: .vb
3599:           fill - expected fill as ratio of original fill.
3600:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3601:                    Run with the option -info to determine an optimal value to use
3602: .ve

3604:   Level: developer

3606:   Notes:
3607:   See `MatLUFactorSymbolic()` for the nonsymmetric case. See also
3608:   `MatCholeskyFactor()` and `MatCholeskyFactorNumeric()`.

3610:   Most users should employ the `KSP` interface for linear solvers
3611:   instead of working directly with matrix algebra routines such as this.
3612:   See, e.g., `KSPCreate()`.

3614:   Fortran Note:
3615:   A valid (non-null) `info` argument must be provided

3617: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactor()`, `MatCholeskyFactorNumeric()`,
3618:           `MatGetOrdering()`
3619: @*/
3620: PetscErrorCode MatCholeskyFactorSymbolic(Mat fact, Mat mat, IS perm, const MatFactorInfo *info)
3621: {
3622:   MatFactorInfo tinfo;

3624:   PetscFunctionBegin;
3628:   if (info) PetscAssertPointer(info, 4);
3631:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "Matrix must be square");
3632:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3633:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3634:   MatCheckPreallocated(mat, 2);
3635:   if (!info) {
3636:     PetscCall(MatFactorInfoInitialize(&tinfo));
3637:     info = &tinfo;
3638:   }

3640:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_CholeskyFactorSymbolic, mat, perm, 0, 0));
3641:   PetscUseTypeMethod(fact, choleskyfactorsymbolic, mat, perm, info);
3642:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_CholeskyFactorSymbolic, mat, perm, 0, 0));
3643:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3644:   PetscFunctionReturn(PETSC_SUCCESS);
3645: }

3647: /*@
3648:   MatCholeskyFactorNumeric - Performs numeric Cholesky factorization
3649:   of a symmetric matrix. Call this routine after first calling `MatGetFactor()` and
3650:   `MatCholeskyFactorSymbolic()`.

3652:   Collective

3654:   Input Parameters:
3655: + fact - the factor matrix obtained with `MatGetFactor()`, where the factored values are stored
3656: . mat  - the initial matrix that is to be factored
3657: - info - options for factorization

3659:   Level: developer

3661:   Note:
3662:   Most users should employ the `KSP` interface for linear solvers
3663:   instead of working directly with matrix algebra routines such as this.
3664:   See, e.g., `KSPCreate()`.

3666:   Fortran Note:
3667:   A valid (non-null) `info` argument must be provided

3669: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatCholeskyFactorSymbolic()`, `MatCholeskyFactor()`, `MatLUFactorNumeric()`
3670: @*/
3671: PetscErrorCode MatCholeskyFactorNumeric(Mat fact, Mat mat, const MatFactorInfo *info)
3672: {
3673:   MatFactorInfo tinfo;

3675:   PetscFunctionBegin;
3680:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3681:   PetscCheck(mat->rmap->N == (fact)->rmap->N && mat->cmap->N == (fact)->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Mat fact: global dim %" PetscInt_FMT " should = %" PetscInt_FMT " %" PetscInt_FMT " should = %" PetscInt_FMT,
3682:              mat->rmap->N, (fact)->rmap->N, mat->cmap->N, (fact)->cmap->N);
3683:   MatCheckPreallocated(mat, 2);
3684:   if (!info) {
3685:     PetscCall(MatFactorInfoInitialize(&tinfo));
3686:     info = &tinfo;
3687:   }

3689:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_CholeskyFactorNumeric, mat, fact, 0, 0));
3690:   else PetscCall(PetscLogEventBegin(MAT_CholeskyFactor, mat, fact, 0, 0));
3691:   PetscUseTypeMethod(fact, choleskyfactornumeric, mat, info);
3692:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_CholeskyFactorNumeric, mat, fact, 0, 0));
3693:   else PetscCall(PetscLogEventEnd(MAT_CholeskyFactor, mat, fact, 0, 0));
3694:   PetscCall(MatViewFromOptions(fact, NULL, "-mat_factor_view"));
3695:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3696:   PetscFunctionReturn(PETSC_SUCCESS);
3697: }

3699: /*@
3700:   MatQRFactor - Performs in-place QR factorization of matrix.

3702:   Collective

3704:   Input Parameters:
3705: + mat  - the matrix
3706: . col  - column permutation
3707: - info - options for factorization, includes
3708: .vb
3709:           fill - expected fill as ratio of original fill.
3710:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3711:                    Run with the option -info to determine an optimal value to use
3712: .ve

3714:   Level: developer

3716:   Notes:
3717:   Most users should employ the `KSP` interface for linear solvers
3718:   instead of working directly with matrix algebra routines such as this.
3719:   See, e.g., `KSPCreate()`.

3721:   This changes the state of the matrix to a factored matrix; it cannot be used
3722:   for example with `MatSetValues()` unless one first calls `MatSetUnfactored()`.

3724:   Fortran Note:
3725:   A valid (non-null) `info` argument must be provided

3727: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatQRFactorSymbolic()`, `MatQRFactorNumeric()`, `MatLUFactor()`,
3728:           `MatSetUnfactored()`
3729: @*/
3730: PetscErrorCode MatQRFactor(Mat mat, IS col, const MatFactorInfo *info)
3731: {
3732:   PetscFunctionBegin;
3735:   if (info) PetscAssertPointer(info, 3);
3737:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3738:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3739:   MatCheckPreallocated(mat, 1);
3740:   PetscCall(PetscLogEventBegin(MAT_QRFactor, mat, col, 0, 0));
3741:   PetscUseMethod(mat, "MatQRFactor_C", (Mat, IS, const MatFactorInfo *), (mat, col, info));
3742:   PetscCall(PetscLogEventEnd(MAT_QRFactor, mat, col, 0, 0));
3743:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
3744:   PetscFunctionReturn(PETSC_SUCCESS);
3745: }

3747: /*@
3748:   MatQRFactorSymbolic - Performs symbolic QR factorization of matrix.
3749:   Call this routine after `MatGetFactor()` but before calling `MatQRFactorNumeric()`.

3751:   Collective

3753:   Input Parameters:
3754: + fact - the factor matrix obtained with `MatGetFactor()`
3755: . mat  - the matrix
3756: . col  - column permutation
3757: - info - options for factorization, includes
3758: .vb
3759:           fill - expected fill as ratio of original fill.
3760:           dtcol - pivot tolerance (0 no pivot, 1 full column pivoting)
3761:                    Run with the option -info to determine an optimal value to use
3762: .ve

3764:   Level: developer

3766:   Note:
3767:   Most users should employ the `KSP` interface for linear solvers
3768:   instead of working directly with matrix algebra routines such as this.
3769:   See, e.g., `KSPCreate()`.

3771:   Fortran Note:
3772:   A valid (non-null) `info` argument must be provided

3774: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatFactorInfo`, `MatQRFactor()`, `MatQRFactorNumeric()`, `MatLUFactor()`, `MatFactorInfoInitialize()`
3775: @*/
3776: PetscErrorCode MatQRFactorSymbolic(Mat fact, Mat mat, IS col, const MatFactorInfo *info)
3777: {
3778:   MatFactorInfo tinfo;

3780:   PetscFunctionBegin;
3784:   if (info) PetscAssertPointer(info, 4);
3787:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3788:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
3789:   MatCheckPreallocated(mat, 2);
3790:   if (!info) {
3791:     PetscCall(MatFactorInfoInitialize(&tinfo));
3792:     info = &tinfo;
3793:   }

3795:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_QRFactorSymbolic, fact, mat, col, 0));
3796:   PetscUseMethod(fact, "MatQRFactorSymbolic_C", (Mat, Mat, IS, const MatFactorInfo *), (fact, mat, col, info));
3797:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_QRFactorSymbolic, fact, mat, col, 0));
3798:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3799:   PetscFunctionReturn(PETSC_SUCCESS);
3800: }

3802: /*@
3803:   MatQRFactorNumeric - Performs numeric QR factorization of a matrix.
3804:   Call this routine after first calling `MatGetFactor()`, and `MatQRFactorSymbolic()`.

3806:   Collective

3808:   Input Parameters:
3809: + fact - the factor matrix obtained with `MatGetFactor()`
3810: . mat  - the matrix
3811: - info - options for factorization

3813:   Level: developer

3815:   Notes:
3816:   See `MatQRFactor()` for in-place factorization.

3818:   Most users should employ the `KSP` interface for linear solvers
3819:   instead of working directly with matrix algebra routines such as this.
3820:   See, e.g., `KSPCreate()`.

3822:   Fortran Note:
3823:   A valid (non-null) `info` argument must be provided

3825: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorInfo`, `MatGetFactor()`, `MatQRFactor()`, `MatQRFactorSymbolic()`, `MatLUFactor()`
3826: @*/
3827: PetscErrorCode MatQRFactorNumeric(Mat fact, Mat mat, const MatFactorInfo *info)
3828: {
3829:   MatFactorInfo tinfo;

3831:   PetscFunctionBegin;
3836:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
3837:   PetscCheck(mat->rmap->N == fact->rmap->N && mat->cmap->N == fact->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Mat fact: global dimensions are different %" PetscInt_FMT " should = %" PetscInt_FMT " %" PetscInt_FMT " should = %" PetscInt_FMT,
3838:              mat->rmap->N, (fact)->rmap->N, mat->cmap->N, (fact)->cmap->N);

3840:   MatCheckPreallocated(mat, 2);
3841:   if (!info) {
3842:     PetscCall(MatFactorInfoInitialize(&tinfo));
3843:     info = &tinfo;
3844:   }

3846:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_QRFactorNumeric, mat, fact, 0, 0));
3847:   else PetscCall(PetscLogEventBegin(MAT_QRFactor, mat, fact, 0, 0));
3848:   PetscUseMethod(fact, "MatQRFactorNumeric_C", (Mat, Mat, const MatFactorInfo *), (fact, mat, info));
3849:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_QRFactorNumeric, mat, fact, 0, 0));
3850:   else PetscCall(PetscLogEventEnd(MAT_QRFactor, mat, fact, 0, 0));
3851:   PetscCall(MatViewFromOptions(fact, NULL, "-mat_factor_view"));
3852:   PetscCall(PetscObjectStateIncrease((PetscObject)fact));
3853:   PetscFunctionReturn(PETSC_SUCCESS);
3854: }

3856: /*@
3857:   MatSolve - Solves $A x = b$, given a factored matrix.

3859:   Neighbor-wise Collective

3861:   Input Parameters:
3862: + mat - the factored matrix
3863: - b   - the right-hand-side vector

3865:   Output Parameter:
3866: . x - the result vector

3868:   Level: developer

3870:   Notes:
3871:   The vectors `b` and `x` cannot be the same. I.e., one cannot
3872:   call `MatSolve`(A,x,x).

3874:   Most users should employ the `KSP` interface for linear solvers
3875:   instead of working directly with matrix algebra routines such as this.
3876:   See, e.g., `KSPCreate()`.

3878: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatLUFactor()`, `MatSolveAdd()`, `MatSolveTranspose()`, `MatSolveTransposeAdd()`
3879: @*/
3880: PetscErrorCode MatSolve(Mat mat, Vec b, Vec x)
3881: {
3882:   PetscFunctionBegin;
3887:   PetscCheckSameComm(mat, 1, b, 2);
3888:   PetscCheckSameComm(mat, 1, x, 3);
3889:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
3890:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
3891:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
3892:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
3893:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3894:   MatCheckPreallocated(mat, 1);

3896:   PetscCall(PetscLogEventBegin(MAT_Solve, mat, b, x, 0));
3897:   PetscCall(VecFlag(x, mat->factorerrortype));
3898:   if (mat->factorerrortype) PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
3899:   else PetscUseTypeMethod(mat, solve, b, x);
3900:   PetscCall(PetscLogEventEnd(MAT_Solve, mat, b, x, 0));
3901:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
3902:   PetscFunctionReturn(PETSC_SUCCESS);
3903: }

3905: static PetscErrorCode MatMatSolve_Basic(Mat A, Mat B, Mat X, PetscBool trans)
3906: {
3907:   Vec      b, x;
3908:   PetscInt N;
3909:   PetscErrorCode (*f)(Mat, Vec, Vec);
3910:   PetscBool Abound, Bneedconv = PETSC_FALSE, Xneedconv = PETSC_FALSE;

3912:   PetscFunctionBegin;
3913:   f = (!trans || (!A->ops->solvetranspose && A->symmetric)) ? A->ops->solve : A->ops->solvetranspose;
3914:   PetscCheck(f, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Mat type %s", ((PetscObject)A)->type_name);
3915:   PetscCall(MatBoundToCPU(A, &Abound));
3916:   if (!Abound) {
3917:     PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &Bneedconv, MATSEQDENSE, MATMPIDENSE, ""));
3918:     PetscCall(PetscObjectTypeCompareAny((PetscObject)X, &Xneedconv, MATSEQDENSE, MATMPIDENSE, ""));
3919:   }
3920: #if PetscDefined(HAVE_CUDA)
3921:   if (Bneedconv) PetscCall(MatConvert(B, MATDENSECUDA, MAT_INPLACE_MATRIX, &B));
3922:   if (Xneedconv) PetscCall(MatConvert(X, MATDENSECUDA, MAT_INPLACE_MATRIX, &X));
3923: #elif PetscDefined(HAVE_HIP)
3924:   if (Bneedconv) PetscCall(MatConvert(B, MATDENSEHIP, MAT_INPLACE_MATRIX, &B));
3925:   if (Xneedconv) PetscCall(MatConvert(X, MATDENSEHIP, MAT_INPLACE_MATRIX, &X));
3926: #endif
3927:   PetscCall(MatGetSize(B, NULL, &N));
3928:   for (PetscInt i = 0; i < N; i++) {
3929:     PetscCall(MatDenseGetColumnVecRead(B, i, &b));
3930:     PetscCall(MatDenseGetColumnVecWrite(X, i, &x));
3931:     PetscCall((*f)(A, b, x));
3932:     PetscCall(MatDenseRestoreColumnVecWrite(X, i, &x));
3933:     PetscCall(MatDenseRestoreColumnVecRead(B, i, &b));
3934:   }
3935:   if (Bneedconv) PetscCall(MatConvert(B, MATDENSE, MAT_INPLACE_MATRIX, &B));
3936:   if (Xneedconv) PetscCall(MatConvert(X, MATDENSE, MAT_INPLACE_MATRIX, &X));
3937:   PetscFunctionReturn(PETSC_SUCCESS);
3938: }

3940: /*@
3941:   MatMatSolve - Solves $A X = B$, given a factored matrix.

3943:   Neighbor-wise Collective

3945:   Input Parameters:
3946: + A - the factored matrix
3947: - B - the right-hand-side matrix `MATDENSE` (or sparse `MATAIJ`-- when using MUMPS)

3949:   Output Parameter:
3950: . X - the result matrix (dense matrix)

3952:   Level: developer

3954:   Note:
3955:   If `B` is a `MATDENSE` matrix then one can call `MatMatSolve`(A,B,B) except with `MATSOLVERMKL_CPARDISO`;
3956:   otherwise, `B` and `X` cannot be the same.

3958: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSolve()`, `MatMatSolveTranspose()`, `MatLUFactor()`, `MatCholeskyFactor()`
3959: @*/
3960: PetscErrorCode MatMatSolve(Mat A, Mat B, Mat X)
3961: {
3962:   PetscFunctionBegin;
3967:   PetscCheckSameComm(A, 1, B, 2);
3968:   PetscCheckSameComm(A, 1, X, 3);
3969:   PetscCheck(A->cmap->N == X->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat X: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->cmap->N, X->rmap->N);
3970:   PetscCheck(A->rmap->N == B->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, B->rmap->N);
3971:   PetscCheck(X->cmap->N == B->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Solution matrix must have same number of columns as rhs matrix");
3972:   if (!A->rmap->N && !A->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
3973:   MatCheckPreallocated(A, 1);

3975:   PetscCall(PetscLogEventBegin(MAT_MatSolve, A, B, X, 0));
3976:   if (A->factorerrortype) {
3977:     PetscCall(PetscInfo(A, "MatFactorError %d\n", A->factorerrortype));
3978:     PetscCall(MatFlag(X, 1));
3979:   } else if (!A->ops->matsolve) {
3980:     PetscCall(PetscInfo(A, "Mat type %s using basic MatMatSolve\n", ((PetscObject)A)->type_name));
3981:     PetscCall(MatMatSolve_Basic(A, B, X, PETSC_FALSE));
3982:   } else PetscUseTypeMethod(A, matsolve, B, X);
3983:   PetscCall(PetscLogEventEnd(MAT_MatSolve, A, B, X, 0));
3984:   PetscCall(PetscObjectStateIncrease((PetscObject)X));
3985:   PetscFunctionReturn(PETSC_SUCCESS);
3986: }

3988: /*@
3989:   MatMatSolveTranspose - Solves $A^T X = B$, given a factored matrix.

3991:   Neighbor-wise Collective

3993:   Input Parameters:
3994: + A - the factored matrix
3995: - B - the right-hand-side matrix  (`MATDENSE` matrix)

3997:   Output Parameter:
3998: . X - the result matrix (dense matrix)

4000:   Level: developer

4002:   Note:
4003:   The matrices `B` and `X` cannot be the same. I.e., one cannot
4004:   call `MatMatSolveTranspose`(A,X,X).

4006: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSolveTranspose()`, `MatMatSolve()`, `MatLUFactor()`, `MatCholeskyFactor()`
4007: @*/
4008: PetscErrorCode MatMatSolveTranspose(Mat A, Mat B, Mat X)
4009: {
4010:   PetscFunctionBegin;
4015:   PetscCheckSameComm(A, 1, B, 2);
4016:   PetscCheckSameComm(A, 1, X, 3);
4017:   PetscCheck(X != B, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_IDN, "X and B must be different matrices");
4018:   PetscCheck(A->cmap->N == X->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat X: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->cmap->N, X->rmap->N);
4019:   PetscCheck(A->rmap->N == B->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, B->rmap->N);
4020:   PetscCheck(A->rmap->n == B->rmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat A,Mat B: local dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->n, B->rmap->n);
4021:   PetscCheck(X->cmap->N >= B->cmap->N, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Solution matrix must have same number of columns as rhs matrix");
4022:   if (!A->rmap->N && !A->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4023:   MatCheckPreallocated(A, 1);

4025:   PetscCall(PetscLogEventBegin(MAT_MatSolve, A, B, X, 0));
4026:   if (A->factorerrortype) {
4027:     PetscCall(PetscInfo(A, "MatFactorError %d\n", A->factorerrortype));
4028:     PetscCall(MatFlag(X, 1));
4029:   } else if (!A->ops->matsolvetranspose) {
4030:     PetscCall(PetscInfo(A, "Mat type %s using basic MatMatSolveTranspose\n", ((PetscObject)A)->type_name));
4031:     PetscCall(MatMatSolve_Basic(A, B, X, PETSC_TRUE));
4032:   } else PetscUseTypeMethod(A, matsolvetranspose, B, X);
4033:   PetscCall(PetscLogEventEnd(MAT_MatSolve, A, B, X, 0));
4034:   PetscCall(PetscObjectStateIncrease((PetscObject)X));
4035:   PetscFunctionReturn(PETSC_SUCCESS);
4036: }

4038: /*@
4039:   MatMatTransposeSolve - Solves $A X = B^T$, given a factored matrix.

4041:   Neighbor-wise Collective

4043:   Input Parameters:
4044: + A  - the factored matrix
4045: - Bt - the transpose of right-hand-side matrix as a `MATDENSE`

4047:   Output Parameter:
4048: . X - the result matrix (dense matrix)

4050:   Level: developer

4052:   Note:
4053:   For MUMPS, it only supports centralized sparse compressed column format on the host process for right-hand side matrix. User must create `Bt` in sparse compressed row
4054:   format on the host process and call `MatMatTransposeSolve()` to implement MUMPS' `MatMatSolve()`.

4056: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatMatSolve()`, `MatMatSolveTranspose()`, `MatLUFactor()`, `MatCholeskyFactor()`
4057: @*/
4058: PetscErrorCode MatMatTransposeSolve(Mat A, Mat Bt, Mat X)
4059: {
4060:   PetscFunctionBegin;
4065:   PetscCheckSameComm(A, 1, Bt, 2);
4066:   PetscCheckSameComm(A, 1, X, 3);

4068:   PetscCheck(X != Bt, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_IDN, "X and B must be different matrices");
4069:   PetscCheck(A->cmap->N == X->rmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat X: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->cmap->N, X->rmap->N);
4070:   PetscCheck(A->rmap->N == Bt->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat Bt: global dim %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, Bt->cmap->N);
4071:   PetscCheck(X->cmap->N >= Bt->rmap->N, PetscObjectComm((PetscObject)X), PETSC_ERR_ARG_SIZ, "Solution matrix must have same number of columns as row number of the rhs matrix");
4072:   if (!A->rmap->N && !A->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4073:   PetscCheck(A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Unfactored matrix");
4074:   MatCheckPreallocated(A, 1);

4076:   PetscCall(PetscLogEventBegin(MAT_MatTrSolve, A, Bt, X, 0));
4077:   if (A->factorerrortype) {
4078:     PetscCall(PetscInfo(A, "MatFactorError %d\n", A->factorerrortype));
4079:     PetscCall(MatFlag(X, 1));
4080:   } else PetscUseTypeMethod(A, mattransposesolve, Bt, X);
4081:   PetscCall(PetscLogEventEnd(MAT_MatTrSolve, A, Bt, X, 0));
4082:   PetscCall(PetscObjectStateIncrease((PetscObject)X));
4083:   PetscFunctionReturn(PETSC_SUCCESS);
4084: }

4086: /*@
4087:   MatForwardSolve - Solves $L x = b$, given a factored matrix, $A = LU$, or
4088:   $U^T D^{1/2} x = b$, given a factored symmetric matrix, $A = U^T D U$,

4090:   Neighbor-wise Collective

4092:   Input Parameters:
4093: + mat - the factored matrix
4094: - b   - the right-hand-side vector

4096:   Output Parameter:
4097: . x - the result vector

4099:   Level: developer

4101:   Notes:
4102:   `MatSolve()` should be used for most applications, as it performs
4103:   a forward solve followed by a backward solve.

4105:   The vectors `b` and `x` cannot be the same,  i.e., one cannot
4106:   call `MatForwardSolve`(A,x,x).

4108:   For matrix in `MATSEQBAIJ` format with block size larger than 1,
4109:   the diagonal blocks are not implemented as $D = D^{1/2} D^{1/2}$ yet.
4110:   `MatForwardSolve()` solves $U^T D y = b$, and
4111:   `MatBackwardSolve()` solves $U x = y$.
4112:   Thus they do not provide a symmetric preconditioner.

4114: .seealso: [](ch_matrices), `Mat`, `MatBackwardSolve()`, `MatGetFactor()`, `MatSolve()`
4115: @*/
4116: PetscErrorCode MatForwardSolve(Mat mat, Vec b, Vec x)
4117: {
4118:   PetscFunctionBegin;
4123:   PetscCheckSameComm(mat, 1, b, 2);
4124:   PetscCheckSameComm(mat, 1, x, 3);
4125:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4126:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
4127:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
4128:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
4129:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4130:   MatCheckPreallocated(mat, 1);

4132:   PetscCall(PetscLogEventBegin(MAT_ForwardSolve, mat, b, x, 0));
4133:   PetscUseTypeMethod(mat, forwardsolve, b, x);
4134:   PetscCall(PetscLogEventEnd(MAT_ForwardSolve, mat, b, x, 0));
4135:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4136:   PetscFunctionReturn(PETSC_SUCCESS);
4137: }

4139: /*@
4140:   MatBackwardSolve - Solves $U x = b$, given a factored matrix, $A = LU$.
4141:   $D^{1/2} U x = b$, given a factored symmetric matrix, $A = U^T D U$,

4143:   Neighbor-wise Collective

4145:   Input Parameters:
4146: + mat - the factored matrix
4147: - b   - the right-hand-side vector

4149:   Output Parameter:
4150: . x - the result vector

4152:   Level: developer

4154:   Notes:
4155:   `MatSolve()` should be used for most applications, as it performs
4156:   a forward solve followed by a backward solve.

4158:   The vectors `b` and `x` cannot be the same. I.e., one cannot
4159:   call `MatBackwardSolve`(A,x,x).

4161:   For matrix in `MATSEQBAIJ` format with block size larger than 1,
4162:   the diagonal blocks are not implemented as $D = D^{1/2} D^{1/2}$ yet.
4163:   `MatForwardSolve()` solves $U^T D y = b$, and
4164:   `MatBackwardSolve()` solves $U x = y$.
4165:   Thus they do not provide a symmetric preconditioner.

4167: .seealso: [](ch_matrices), `Mat`, `MatForwardSolve()`, `MatGetFactor()`, `MatSolve()`
4168: @*/
4169: PetscErrorCode MatBackwardSolve(Mat mat, Vec b, Vec x)
4170: {
4171:   PetscFunctionBegin;
4176:   PetscCheckSameComm(mat, 1, b, 2);
4177:   PetscCheckSameComm(mat, 1, x, 3);
4178:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4179:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
4180:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
4181:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
4182:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4183:   MatCheckPreallocated(mat, 1);

4185:   PetscCall(PetscLogEventBegin(MAT_BackwardSolve, mat, b, x, 0));
4186:   PetscUseTypeMethod(mat, backwardsolve, b, x);
4187:   PetscCall(PetscLogEventEnd(MAT_BackwardSolve, mat, b, x, 0));
4188:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4189:   PetscFunctionReturn(PETSC_SUCCESS);
4190: }

4192: /*@
4193:   MatSolveAdd - Computes $x = y + A^{-1} b$, given a factored matrix.

4195:   Neighbor-wise Collective

4197:   Input Parameters:
4198: + mat - the factored matrix
4199: . b   - the right-hand-side vector
4200: - y   - the vector to be added to

4202:   Output Parameter:
4203: . x - the result vector

4205:   Level: developer

4207:   Note:
4208:   The vectors `b` and `x` cannot be the same. I.e., one cannot
4209:   call `MatSolveAdd`(A,x,y,x).

4211: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatSolve()`, `MatGetFactor()`, `MatSolveTranspose()`, `MatSolveTransposeAdd()`
4212: @*/
4213: PetscErrorCode MatSolveAdd(Mat mat, Vec b, Vec y, Vec x)
4214: {
4215:   PetscScalar one = 1.0;
4216:   Vec         tmp;

4218:   PetscFunctionBegin;
4224:   PetscCheckSameComm(mat, 1, b, 2);
4225:   PetscCheckSameComm(mat, 1, y, 3);
4226:   PetscCheckSameComm(mat, 1, x, 4);
4227:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4228:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
4229:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
4230:   PetscCheck(mat->rmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, y->map->N);
4231:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
4232:   PetscCheck(x->map->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vec x,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, x->map->n, y->map->n);
4233:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4234:   MatCheckPreallocated(mat, 1);

4236:   PetscCall(PetscLogEventBegin(MAT_SolveAdd, mat, b, x, y));
4237:   PetscCall(VecFlag(x, mat->factorerrortype));
4238:   if (mat->factorerrortype) {
4239:     PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
4240:   } else if (mat->ops->solveadd) {
4241:     PetscUseTypeMethod(mat, solveadd, b, y, x);
4242:   } else {
4243:     /* do the solve then the add manually */
4244:     if (x != y) {
4245:       PetscCall(MatSolve(mat, b, x));
4246:       PetscCall(VecAXPY(x, one, y));
4247:     } else {
4248:       PetscCall(VecDuplicate(x, &tmp));
4249:       PetscCall(VecCopy(x, tmp));
4250:       PetscCall(MatSolve(mat, b, x));
4251:       PetscCall(VecAXPY(x, one, tmp));
4252:       PetscCall(VecDestroy(&tmp));
4253:     }
4254:   }
4255:   PetscCall(PetscLogEventEnd(MAT_SolveAdd, mat, b, x, y));
4256:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4257:   PetscFunctionReturn(PETSC_SUCCESS);
4258: }

4260: /*@
4261:   MatSolveTranspose - Solves $A^T x = b$, given a factored matrix.

4263:   Neighbor-wise Collective

4265:   Input Parameters:
4266: + mat - the factored matrix
4267: - b   - the right-hand-side vector

4269:   Output Parameter:
4270: . x - the result vector

4272:   Level: developer

4274:   Notes:
4275:   The vectors `b` and `x` cannot be the same. I.e., one cannot
4276:   call `MatSolveTranspose`(A,x,x).

4278:   Most users should employ the `KSP` interface for linear solvers
4279:   instead of working directly with matrix algebra routines such as this.
4280:   See, e.g., `KSPCreate()`.

4282: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `KSP`, `MatSolve()`, `MatSolveAdd()`, `MatSolveTransposeAdd()`
4283: @*/
4284: PetscErrorCode MatSolveTranspose(Mat mat, Vec b, Vec x)
4285: {
4286:   PetscErrorCode (*f)(Mat, Vec, Vec) = (!mat->ops->solvetranspose && mat->symmetric) ? mat->ops->solve : mat->ops->solvetranspose;

4288:   PetscFunctionBegin;
4293:   PetscCheckSameComm(mat, 1, b, 2);
4294:   PetscCheckSameComm(mat, 1, x, 3);
4295:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4296:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
4297:   PetscCheck(mat->cmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, b->map->N);
4298:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4299:   MatCheckPreallocated(mat, 1);
4300:   PetscCall(PetscLogEventBegin(MAT_SolveTranspose, mat, b, x, 0));
4301:   PetscCall(VecFlag(x, mat->factorerrortype));
4302:   if (mat->factorerrortype) {
4303:     PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
4304:   } else {
4305:     PetscCheck(f, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Matrix type %s", ((PetscObject)mat)->type_name);
4306:     PetscCall((*f)(mat, b, x));
4307:   }
4308:   PetscCall(PetscLogEventEnd(MAT_SolveTranspose, mat, b, x, 0));
4309:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4310:   PetscFunctionReturn(PETSC_SUCCESS);
4311: }

4313: /*@
4314:   MatSolveTransposeAdd - Computes $x = y + A^{-T} b$
4315:   factored matrix.

4317:   Neighbor-wise Collective

4319:   Input Parameters:
4320: + mat - the factored matrix
4321: . b   - the right-hand-side vector
4322: - y   - the vector to be added to

4324:   Output Parameter:
4325: . x - the result vector

4327:   Level: developer

4329:   Note:
4330:   The vectors `b` and `x` cannot be the same. I.e., one cannot
4331:   call `MatSolveTransposeAdd`(A,x,y,x).

4333: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatSolve()`, `MatSolveAdd()`, `MatSolveTranspose()`
4334: @*/
4335: PetscErrorCode MatSolveTransposeAdd(Mat mat, Vec b, Vec y, Vec x)
4336: {
4337:   PetscScalar one = 1.0;
4338:   Vec         tmp;
4339:   PetscErrorCode (*f)(Mat, Vec, Vec, Vec) = (!mat->ops->solvetransposeadd && mat->symmetric) ? mat->ops->solveadd : mat->ops->solvetransposeadd;

4341:   PetscFunctionBegin;
4347:   PetscCheckSameComm(mat, 1, b, 2);
4348:   PetscCheckSameComm(mat, 1, y, 3);
4349:   PetscCheckSameComm(mat, 1, x, 4);
4350:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
4351:   PetscCheck(mat->rmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, x->map->N);
4352:   PetscCheck(mat->cmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, b->map->N);
4353:   PetscCheck(mat->cmap->N == y->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec y: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, y->map->N);
4354:   PetscCheck(x->map->n == y->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Vec x,Vec y: local dim %" PetscInt_FMT " %" PetscInt_FMT, x->map->n, y->map->n);
4355:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);
4356:   MatCheckPreallocated(mat, 1);

4358:   PetscCall(PetscLogEventBegin(MAT_SolveTransposeAdd, mat, b, x, y));
4359:   PetscCall(VecFlag(x, mat->factorerrortype));
4360:   if (mat->factorerrortype) {
4361:     PetscCall(PetscInfo(mat, "MatFactorError %d\n", mat->factorerrortype));
4362:   } else if (f) {
4363:     PetscCall((*f)(mat, b, y, x));
4364:   } else {
4365:     /* do the solve then the add manually */
4366:     if (x != y) {
4367:       PetscCall(MatSolveTranspose(mat, b, x));
4368:       PetscCall(VecAXPY(x, one, y));
4369:     } else {
4370:       PetscCall(VecDuplicate(x, &tmp));
4371:       PetscCall(VecCopy(x, tmp));
4372:       PetscCall(MatSolveTranspose(mat, b, x));
4373:       PetscCall(VecAXPY(x, one, tmp));
4374:       PetscCall(VecDestroy(&tmp));
4375:     }
4376:   }
4377:   PetscCall(PetscLogEventEnd(MAT_SolveTransposeAdd, mat, b, x, y));
4378:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4379:   PetscFunctionReturn(PETSC_SUCCESS);
4380: }

4382: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
4383: /*@
4384:   MatSOR - Computes relaxation (SOR, Gauss-Seidel) sweeps.

4386:   Neighbor-wise Collective

4388:   Input Parameters:
4389: + mat   - the matrix
4390: . b     - the right-hand side
4391: . omega - the relaxation factor
4392: . flag  - flag indicating the type of SOR (see below)
4393: . shift - diagonal shift
4394: . its   - the number of iterations
4395: - lits  - the number of local iterations

4397:   Output Parameter:
4398: . x - the solution (can contain an initial guess, use option `SOR_ZERO_INITIAL_GUESS` to indicate no guess)

4400:   SOR Flags:
4401: +     `SOR_FORWARD_SWEEP` - forward SOR
4402: .     `SOR_BACKWARD_SWEEP` - backward SOR
4403: .     `SOR_SYMMETRIC_SWEEP` - SSOR (symmetric SOR)
4404: .     `SOR_LOCAL_FORWARD_SWEEP` - local forward SOR
4405: .     `SOR_LOCAL_BACKWARD_SWEEP` - local forward SOR
4406: .     `SOR_LOCAL_SYMMETRIC_SWEEP` - local SSOR
4407: .     `SOR_EISENSTAT` - SOR with Eisenstat trick
4408: .     `SOR_APPLY_UPPER`, `SOR_APPLY_LOWER` - applies upper/lower triangular part of matrix to vector (with `omega`)
4409: -     `SOR_ZERO_INITIAL_GUESS` - zero initial guess

4411:   Level: developer

4413:   Notes:
4414:   `SOR_LOCAL_FORWARD_SWEEP`, `SOR_LOCAL_BACKWARD_SWEEP`, and
4415:   `SOR_LOCAL_SYMMETRIC_SWEEP` perform separate independent smoothings
4416:   on each process.

4418:   Application programmers will not generally use `MatSOR()` directly,
4419:   but instead will employ `PCSOR` or `PCEISENSTAT`

4421:   For `MATBAIJ`, `MATSBAIJ`, and `MATAIJ` matrices with inodes, this does a block SOR smoothing, otherwise it does a pointwise smoothing.
4422:   For `MATAIJ` matrices with inodes, the block sizes are determined by the inode sizes, not the block size set with `MatSetBlockSize()`

4424:   Vectors `x` and `b` CANNOT be the same

4426:   The flags are implemented as bitwise inclusive or operations.
4427:   For example, use (`SOR_ZERO_INITIAL_GUESS` | `SOR_SYMMETRIC_SWEEP`)
4428:   to specify a zero initial guess for SSOR.

4430:   Developer Note:
4431:   We should add block SOR support for `MATAIJ` matrices with block size set to greater than one and no inodes

4433: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `KSP`, `PC`, `MatGetFactor()`
4434: @*/
4435: PetscErrorCode MatSOR(Mat mat, Vec b, PetscReal omega, MatSORType flag, PetscReal shift, PetscInt its, PetscInt lits, Vec x)
4436: {
4437:   PetscFunctionBegin;
4442:   PetscCheckSameComm(mat, 1, b, 2);
4443:   PetscCheckSameComm(mat, 1, x, 8);
4444:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4445:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4446:   PetscCheck(mat->cmap->N == x->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec x: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->cmap->N, x->map->N);
4447:   PetscCheck(mat->rmap->N == b->map->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: global dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->N, b->map->N);
4448:   PetscCheck(mat->rmap->n == b->map->n, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Mat mat,Vec b: local dim %" PetscInt_FMT " %" PetscInt_FMT, mat->rmap->n, b->map->n);
4449:   PetscCheck(its > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Relaxation requires global its %" PetscInt_FMT " positive", its);
4450:   PetscCheck(lits > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Relaxation requires local its %" PetscInt_FMT " positive", lits);
4451:   PetscCheck(b != x, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "b and x vector cannot be the same");

4453:   MatCheckPreallocated(mat, 1);
4454:   PetscCall(PetscLogEventBegin(MAT_SOR, mat, b, x, 0));
4455:   PetscUseTypeMethod(mat, sor, b, omega, flag, shift, its, lits, x);
4456:   PetscCall(PetscLogEventEnd(MAT_SOR, mat, b, x, 0));
4457:   PetscCall(PetscObjectStateIncrease((PetscObject)x));
4458:   PetscFunctionReturn(PETSC_SUCCESS);
4459: }

4461: /*
4462:       Default matrix copy routine.
4463: */
4464: PetscErrorCode MatCopy_Basic(Mat A, Mat B, MatStructure str)
4465: {
4466:   PetscInt           i, rstart = 0, rend = 0, nz;
4467:   const PetscInt    *cwork;
4468:   const PetscScalar *vwork;

4470:   PetscFunctionBegin;
4471:   if (B->assembled) PetscCall(MatZeroEntries(B));
4472:   if (str == SAME_NONZERO_PATTERN) {
4473:     PetscCall(MatGetOwnershipRange(A, &rstart, &rend));
4474:     for (i = rstart; i < rend; i++) {
4475:       PetscCall(MatGetRow(A, i, &nz, &cwork, &vwork));
4476:       PetscCall(MatSetValues(B, 1, &i, nz, cwork, vwork, INSERT_VALUES));
4477:       PetscCall(MatRestoreRow(A, i, &nz, &cwork, &vwork));
4478:     }
4479:   } else {
4480:     PetscCall(MatAYPX(B, 0.0, A, str));
4481:   }
4482:   PetscCall(MatAssemblyBegin(B, MAT_FINAL_ASSEMBLY));
4483:   PetscCall(MatAssemblyEnd(B, MAT_FINAL_ASSEMBLY));
4484:   PetscFunctionReturn(PETSC_SUCCESS);
4485: }

4487: /*@
4488:   MatCopy - Copies a matrix to another matrix.

4490:   Collective

4492:   Input Parameters:
4493: + A   - the matrix
4494: - str - `SAME_NONZERO_PATTERN` or `DIFFERENT_NONZERO_PATTERN`

4496:   Output Parameter:
4497: . B - where the copy is put

4499:   Level: intermediate

4501:   Notes:
4502:   If you use `SAME_NONZERO_PATTERN`, then the two matrices must have the same nonzero pattern or the routine will crash.

4504:   `MatCopy()` copies the matrix entries of a matrix to another existing
4505:   matrix (after first zeroing the second matrix). A related routine is
4506:   `MatConvert()`, which first creates a new matrix and then copies the data.

4508: .seealso: [](ch_matrices), `Mat`, `MatConvert()`, `MatDuplicate()`
4509: @*/
4510: PetscErrorCode MatCopy(Mat A, Mat B, MatStructure str)
4511: {
4512:   PetscInt i;

4514:   PetscFunctionBegin;
4519:   PetscCheckSameComm(A, 1, B, 2);
4520:   MatCheckPreallocated(B, 2);
4521:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4522:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4523:   PetscCheck(A->rmap->N == B->rmap->N && A->cmap->N == B->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim (%" PetscInt_FMT ",%" PetscInt_FMT ") (%" PetscInt_FMT ",%" PetscInt_FMT ")", A->rmap->N, B->rmap->N,
4524:              A->cmap->N, B->cmap->N);
4525:   MatCheckPreallocated(A, 1);
4526:   if (A == B) PetscFunctionReturn(PETSC_SUCCESS);

4528:   PetscCall(PetscLogEventBegin(MAT_Copy, A, B, 0, 0));
4529:   if (A->ops->copy) PetscUseTypeMethod(A, copy, B, str);
4530:   else PetscCall(MatCopy_Basic(A, B, str));

4532:   B->stencil.dim = A->stencil.dim;
4533:   B->stencil.noc = A->stencil.noc;
4534:   for (i = 0; i <= A->stencil.dim + (A->stencil.noc ? 0 : -1); i++) {
4535:     B->stencil.dims[i]   = A->stencil.dims[i];
4536:     B->stencil.starts[i] = A->stencil.starts[i];
4537:   }

4539:   PetscCall(PetscLogEventEnd(MAT_Copy, A, B, 0, 0));
4540:   PetscCall(PetscObjectStateIncrease((PetscObject)B));
4541:   PetscFunctionReturn(PETSC_SUCCESS);
4542: }

4544: /*@
4545:   MatConvert - Converts a matrix to another matrix, either of the same
4546:   or different type.

4548:   Collective

4550:   Input Parameters:
4551: + mat     - the matrix
4552: . newtype - new matrix type. Use `MATSAME` to create a new matrix of the
4553:             same type as the original matrix.
4554: - reuse   - denotes if the destination matrix is to be created or reused.
4555:             Use `MAT_INPLACE_MATRIX` for inplace conversion (that is when you want the input `Mat` to be changed to contain the matrix in the new format), otherwise use
4556:             `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX` (can only be used after the first call was made with `MAT_INITIAL_MATRIX`, causes the matrix space in M to be reused).

4558:   Output Parameter:
4559: . M - pointer to place new matrix

4561:   Level: intermediate

4563:   Notes:
4564:   `MatConvert()` first creates a new matrix and then copies the data from
4565:   the first matrix. A related routine is `MatCopy()`, which copies the matrix
4566:   entries of one matrix to another already existing matrix context.

4568:   Cannot be used to convert a sequential matrix to parallel or parallel to sequential,
4569:   the MPI communicator of the generated matrix is always the same as the communicator
4570:   of the input matrix.

4572: .seealso: [](ch_matrices), `Mat`, `MatCopy()`, `MatDuplicate()`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`
4573: @*/
4574: PetscErrorCode MatConvert(Mat mat, MatType newtype, MatReuse reuse, Mat *M)
4575: {
4576:   PetscBool  sametype, issame, flg;
4577:   PetscBool3 issymmetric, ishermitian, isspd;
4578:   char       convname[256], mtype[256];
4579:   Mat        B;

4581:   PetscFunctionBegin;
4584:   PetscAssertPointer(M, 4);
4585:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
4586:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
4587:   MatCheckPreallocated(mat, 1);

4589:   PetscCall(PetscOptionsGetString(((PetscObject)mat)->options, ((PetscObject)mat)->prefix, "-matconvert_type", mtype, sizeof(mtype), &flg));
4590:   if (flg) newtype = mtype;

4592:   PetscCall(PetscObjectTypeCompare((PetscObject)mat, newtype, &sametype));
4593:   PetscCall(PetscStrcmp(newtype, "same", &issame));
4594:   PetscCheck(!(reuse == MAT_INPLACE_MATRIX) || !(mat != *M), PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "MAT_INPLACE_MATRIX requires same input and output matrix");
4595:   if (reuse == MAT_REUSE_MATRIX) {
4597:     PetscCheck(mat != *M, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "MAT_REUSE_MATRIX means reuse matrix in final argument, perhaps you mean MAT_INPLACE_MATRIX");
4598:   }

4600:   if ((reuse == MAT_INPLACE_MATRIX) && (issame || sametype)) {
4601:     PetscCall(PetscInfo(mat, "Early return for inplace %s %d %d\n", ((PetscObject)mat)->type_name, sametype, issame));
4602:     PetscFunctionReturn(PETSC_SUCCESS);
4603:   }

4605:   /* Cache Mat options because some converters use MatHeaderReplace() */
4606:   issymmetric = mat->symmetric;
4607:   ishermitian = mat->hermitian;
4608:   isspd       = mat->spd;

4610:   if ((sametype || issame) && (reuse == MAT_INITIAL_MATRIX) && mat->ops->duplicate) {
4611:     PetscCall(PetscInfo(mat, "Calling MatDuplicate() for initial matrix %s %d %d\n", ((PetscObject)mat)->type_name, sametype, issame));
4612:     PetscUseTypeMethod(mat, duplicate, MAT_COPY_VALUES, M);
4613:     (*M)->nonzerostate = mat->nonzerostate;
4614:   } else {
4615:     PetscErrorCode (*conv)(Mat, MatType, MatReuse, Mat *) = NULL;
4616:     const char *prefix[3]                                 = {"seq", "mpi", ""};
4617:     PetscInt    i;
4618:     /*
4619:        Order of precedence:
4620:        0) See if newtype is a superclass of the current matrix.
4621:        1) See if a specialized converter is known to the current matrix.
4622:        2) See if a specialized converter is known to the desired matrix class.
4623:        3) See if a good general converter is registered for the desired class
4624:           (as of 6/27/03 only MATMPIADJ falls into this category).
4625:        4) See if a good general converter is known for the current matrix.
4626:        5) Use a really basic converter.
4627:     */

4629:     /* 0) See if newtype is a superclass of the current matrix.
4630:           i.e mat is mpiaij and newtype is aij */
4631:     for (i = 0; i < (PetscInt)PETSC_STATIC_ARRAY_LENGTH(prefix); i++) {
4632:       PetscCall(PetscStrncpy(convname, prefix[i], sizeof(convname)));
4633:       PetscCall(PetscStrlcat(convname, newtype, sizeof(convname)));
4634:       PetscCall(PetscStrcmp(convname, ((PetscObject)mat)->type_name, &flg));
4635:       PetscCall(PetscInfo(mat, "Check superclass %s %s -> %d\n", convname, ((PetscObject)mat)->type_name, flg));
4636:       if (flg) {
4637:         if (reuse == MAT_INPLACE_MATRIX) {
4638:           PetscCall(PetscInfo(mat, "Early return\n"));
4639:           PetscFunctionReturn(PETSC_SUCCESS);
4640:         } else if (reuse == MAT_INITIAL_MATRIX && mat->ops->duplicate) {
4641:           PetscCall(PetscInfo(mat, "Calling MatDuplicate()\n"));
4642:           PetscUseTypeMethod(mat, duplicate, MAT_COPY_VALUES, M);
4643:           (*M)->nonzerostate = mat->nonzerostate;
4644:           PetscFunctionReturn(PETSC_SUCCESS);
4645:         } else if (reuse == MAT_REUSE_MATRIX && mat->ops->copy) {
4646:           PetscCall(PetscInfo(mat, "Calling MatCopy()\n"));
4647:           PetscCall(MatCopy(mat, *M, SAME_NONZERO_PATTERN));
4648:           PetscFunctionReturn(PETSC_SUCCESS);
4649:         }
4650:       }
4651:     }
4652:     /* 1) See if a specialized converter is known to the current matrix and the desired class */
4653:     for (i = 0; i < (PetscInt)PETSC_STATIC_ARRAY_LENGTH(prefix); i++) {
4654:       PetscCall(PetscStrncpy(convname, "MatConvert_", sizeof(convname)));
4655:       PetscCall(PetscStrlcat(convname, ((PetscObject)mat)->type_name, sizeof(convname)));
4656:       PetscCall(PetscStrlcat(convname, "_", sizeof(convname)));
4657:       PetscCall(PetscStrlcat(convname, prefix[i], sizeof(convname)));
4658:       PetscCall(PetscStrlcat(convname, issame ? ((PetscObject)mat)->type_name : newtype, sizeof(convname)));
4659:       PetscCall(PetscStrlcat(convname, "_C", sizeof(convname)));
4660:       PetscCall(PetscObjectQueryFunction((PetscObject)mat, convname, &conv));
4661:       PetscCall(PetscInfo(mat, "Check specialized (1) %s (%s) -> %d\n", convname, ((PetscObject)mat)->type_name, !!conv));
4662:       if (conv) goto foundconv;
4663:     }

4665:     /* 2)  See if a specialized converter is known to the desired matrix class. */
4666:     PetscCall(MatCreate(PetscObjectComm((PetscObject)mat), &B));
4667:     PetscCall(MatSetSizes(B, mat->rmap->n, mat->cmap->n, mat->rmap->N, mat->cmap->N));
4668:     PetscCall(MatSetType(B, newtype));
4669:     for (i = 0; i < (PetscInt)PETSC_STATIC_ARRAY_LENGTH(prefix); i++) {
4670:       PetscCall(PetscStrncpy(convname, "MatConvert_", sizeof(convname)));
4671:       PetscCall(PetscStrlcat(convname, ((PetscObject)mat)->type_name, sizeof(convname)));
4672:       PetscCall(PetscStrlcat(convname, "_", sizeof(convname)));
4673:       PetscCall(PetscStrlcat(convname, prefix[i], sizeof(convname)));
4674:       PetscCall(PetscStrlcat(convname, newtype, sizeof(convname)));
4675:       PetscCall(PetscStrlcat(convname, "_C", sizeof(convname)));
4676:       PetscCall(PetscObjectQueryFunction((PetscObject)B, convname, &conv));
4677:       PetscCall(PetscInfo(mat, "Check specialized (2) %s (%s) -> %d\n", convname, ((PetscObject)B)->type_name, !!conv));
4678:       if (conv) {
4679:         PetscCall(MatDestroy(&B));
4680:         goto foundconv;
4681:       }
4682:     }

4684:     /* 3) See if a good general converter is registered for the desired class */
4685:     conv = B->ops->convertfrom;
4686:     PetscCall(PetscInfo(mat, "Check convertfrom (%s) -> %d\n", ((PetscObject)B)->type_name, !!conv));
4687:     PetscCall(MatDestroy(&B));
4688:     if (conv) goto foundconv;

4690:     /* 4) See if a good general converter is known for the current matrix */
4691:     if (mat->ops->convert) conv = mat->ops->convert;
4692:     PetscCall(PetscInfo(mat, "Check general convert (%s) -> %d\n", ((PetscObject)mat)->type_name, !!conv));
4693:     if (conv) goto foundconv;

4695:     /* 5) Use a really basic converter. */
4696:     PetscCall(PetscInfo(mat, "Using MatConvert_Basic()\n"));
4697:     conv = MatConvert_Basic;

4699:   foundconv:
4700:     PetscCall(PetscLogEventBegin(MAT_Convert, mat, 0, 0, 0));
4701:     PetscCall((*conv)(mat, newtype, reuse, M));
4702:     if (mat->rmap->mapping && mat->cmap->mapping && !(*M)->rmap->mapping && !(*M)->cmap->mapping) {
4703:       /* the block sizes must be same if the mappings are copied over */
4704:       (*M)->rmap->bs = mat->rmap->bs;
4705:       (*M)->cmap->bs = mat->cmap->bs;
4706:       PetscCall(PetscObjectReference((PetscObject)mat->rmap->mapping));
4707:       PetscCall(PetscObjectReference((PetscObject)mat->cmap->mapping));
4708:       (*M)->rmap->mapping = mat->rmap->mapping;
4709:       (*M)->cmap->mapping = mat->cmap->mapping;
4710:     }
4711:     (*M)->stencil.dim = mat->stencil.dim;
4712:     (*M)->stencil.noc = mat->stencil.noc;
4713:     for (i = 0; i <= mat->stencil.dim + (mat->stencil.noc ? 0 : -1); i++) {
4714:       (*M)->stencil.dims[i]   = mat->stencil.dims[i];
4715:       (*M)->stencil.starts[i] = mat->stencil.starts[i];
4716:     }
4717:     PetscCall(PetscLogEventEnd(MAT_Convert, mat, 0, 0, 0));
4718:   }
4719:   PetscCall(PetscObjectStateIncrease((PetscObject)*M));

4721:   /* Reset Mat options */
4722:   if (issymmetric != PETSC_BOOL3_UNKNOWN) PetscCall(MatSetOption(*M, MAT_SYMMETRIC, PetscBool3ToBool(issymmetric)));
4723:   if (ishermitian != PETSC_BOOL3_UNKNOWN) PetscCall(MatSetOption(*M, MAT_HERMITIAN, PetscBool3ToBool(ishermitian)));
4724:   if (isspd != PETSC_BOOL3_UNKNOWN) PetscCall(MatSetOption(*M, MAT_SPD, PetscBool3ToBool(isspd)));
4725:   PetscFunctionReturn(PETSC_SUCCESS);
4726: }

4728: /*@
4729:   MatFactorGetSolverType - Returns name of the package providing the factorization routines

4731:   Not Collective

4733:   Input Parameter:
4734: . mat - the matrix, must be a factored matrix

4736:   Output Parameter:
4737: . type - the string name of the package (do not free this string)

4739:   Level: intermediate

4741: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatSolverType`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`
4742: @*/
4743: PetscErrorCode MatFactorGetSolverType(Mat mat, MatSolverType *type)
4744: {
4745:   PetscErrorCode (*conv)(Mat, MatSolverType *);

4747:   PetscFunctionBegin;
4750:   PetscAssertPointer(type, 2);
4751:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Only for factored matrix");
4752:   PetscCall(PetscObjectQueryFunction((PetscObject)mat, "MatFactorGetSolverType_C", &conv));
4753:   if (conv) PetscCall((*conv)(mat, type));
4754:   else *type = MATSOLVERPETSC;
4755:   PetscFunctionReturn(PETSC_SUCCESS);
4756: }

4758: typedef struct _MatSolverTypeForSpecifcType *MatSolverTypeForSpecifcType;
4759: struct _MatSolverTypeForSpecifcType {
4760:   MatType mtype;
4761:   /* no entry for MAT_FACTOR_NONE */
4762:   PetscErrorCode (*createfactor[MAT_FACTOR_NUM_TYPES - 1])(Mat, MatFactorType, Mat *);
4763:   MatSolverTypeForSpecifcType next;
4764: };

4766: typedef struct _MatSolverTypeHolder *MatSolverTypeHolder;
4767: struct _MatSolverTypeHolder {
4768:   char                       *name;
4769:   MatSolverTypeForSpecifcType handlers;
4770:   MatSolverTypeHolder         next;
4771: };

4773: static MatSolverTypeHolder MatSolverTypeHolders = NULL;

4775: /*@
4776:   MatSolverTypeRegister - Registers a `MatSolverType` that works for a particular matrix type

4778:   Logically Collective, No Fortran Support

4780:   Input Parameters:
4781: + package      - name of the package, for example `petsc` or `superlu`
4782: . mtype        - the matrix type that works with this package
4783: . ftype        - the type of factorization supported by the package
4784: - createfactor - routine that will create the factored matrix ready to be used

4786:   Level: developer

4788: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorGetSolverType()`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`,
4789:   `MatGetFactor()`
4790: @*/
4791: PetscErrorCode MatSolverTypeRegister(MatSolverType package, MatType mtype, MatFactorType ftype, PetscErrorCode (*createfactor)(Mat, MatFactorType, Mat *))
4792: {
4793:   MatSolverTypeHolder         next = MatSolverTypeHolders, prev = NULL;
4794:   PetscBool                   flg;
4795:   MatSolverTypeForSpecifcType inext, iprev = NULL;

4797:   PetscFunctionBegin;
4798:   PetscCall(MatInitializePackage());
4799:   if (!next) {
4800:     PetscCall(PetscNew(&MatSolverTypeHolders));
4801:     PetscCall(PetscStrallocpy(package, &MatSolverTypeHolders->name));
4802:     PetscCall(PetscNew(&MatSolverTypeHolders->handlers));
4803:     PetscCall(PetscStrallocpy(mtype, (char **)&MatSolverTypeHolders->handlers->mtype));
4804:     MatSolverTypeHolders->handlers->createfactor[(int)ftype - 1] = createfactor;
4805:     PetscFunctionReturn(PETSC_SUCCESS);
4806:   }
4807:   while (next) {
4808:     PetscCall(PetscStrcasecmp(package, next->name, &flg));
4809:     if (flg) {
4810:       PetscCheck(next->handlers, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MatSolverTypeHolder is missing handlers");
4811:       inext = next->handlers;
4812:       while (inext) {
4813:         PetscCall(PetscStrcasecmp(mtype, inext->mtype, &flg));
4814:         if (flg) {
4815:           inext->createfactor[(int)ftype - 1] = createfactor;
4816:           PetscFunctionReturn(PETSC_SUCCESS);
4817:         }
4818:         iprev = inext;
4819:         inext = inext->next;
4820:       }
4821:       PetscCall(PetscNew(&iprev->next));
4822:       PetscCall(PetscStrallocpy(mtype, (char **)&iprev->next->mtype));
4823:       iprev->next->createfactor[(int)ftype - 1] = createfactor;
4824:       PetscFunctionReturn(PETSC_SUCCESS);
4825:     }
4826:     prev = next;
4827:     next = next->next;
4828:   }
4829:   PetscCall(PetscNew(&prev->next));
4830:   PetscCall(PetscStrallocpy(package, &prev->next->name));
4831:   PetscCall(PetscNew(&prev->next->handlers));
4832:   PetscCall(PetscStrallocpy(mtype, (char **)&prev->next->handlers->mtype));
4833:   prev->next->handlers->createfactor[(int)ftype - 1] = createfactor;
4834:   PetscFunctionReturn(PETSC_SUCCESS);
4835: }

4837: /*@
4838:   MatSolverTypeGet - Gets the function that creates the factor matrix if it exist

4840:   Input Parameters:
4841: + type  - name of the package, for example `petsc` or `superlu`, if this is `NULL`, then the first result that satisfies the other criteria is returned
4842: . ftype - the type of factorization supported by the type
4843: - mtype - the matrix type that works with this type

4845:   Output Parameters:
4846: + foundtype    - `PETSC_TRUE` if the type was registered
4847: . foundmtype   - `PETSC_TRUE` if the type supports the requested mtype
4848: - createfactor - routine that will create the factored matrix ready to be used or `NULL` if not found

4850:   Calling sequence of `createfactor`:
4851: + A     - the matrix providing the factor matrix
4852: . ftype - the `MatFactorType` of the factor requested
4853: - B     - the new factor matrix that responds to MatXXFactorSymbolic,Numeric() functions, such as `MatLUFactorSymbolic()`

4855:   Level: developer

4857:   Note:
4858:   When `type` is `NULL` the available functions are searched for based on the order of the calls to `MatSolverTypeRegister()` in `MatInitializePackage()`.
4859:   Since different PETSc configurations may have different external solvers, seemingly identical runs with different PETSc configurations may use a different solver.
4860:   For example if one configuration had `--download-mumps` while a different one had `--download-superlu_dist`.

4862: .seealso: [](ch_matrices), `Mat`, `MatFactorType`, `MatType`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`, `MatSolverTypeRegister()`, `MatGetFactor()`,
4863:           `MatInitializePackage()`
4864: @*/
4865: PetscErrorCode MatSolverTypeGet(MatSolverType type, MatType mtype, MatFactorType ftype, PetscBool *foundtype, PetscBool *foundmtype, PetscErrorCode (**createfactor)(Mat A, MatFactorType ftype, Mat *B))
4866: {
4867:   MatSolverTypeHolder         next = MatSolverTypeHolders;
4868:   PetscBool                   flg;
4869:   MatSolverTypeForSpecifcType inext;

4871:   PetscFunctionBegin;
4872:   if (foundtype) *foundtype = PETSC_FALSE;
4873:   if (foundmtype) *foundmtype = PETSC_FALSE;
4874:   if (createfactor) *createfactor = NULL;

4876:   if (type) {
4877:     while (next) {
4878:       PetscCall(PetscStrcasecmp(type, next->name, &flg));
4879:       if (flg) {
4880:         if (foundtype) *foundtype = PETSC_TRUE;
4881:         inext = next->handlers;
4882:         while (inext) {
4883:           PetscCall(PetscStrbeginswith(mtype, inext->mtype, &flg));
4884:           if (flg) {
4885:             if (foundmtype) *foundmtype = PETSC_TRUE;
4886:             if (createfactor) *createfactor = inext->createfactor[(int)ftype - 1];
4887:             PetscFunctionReturn(PETSC_SUCCESS);
4888:           }
4889:           inext = inext->next;
4890:         }
4891:       }
4892:       next = next->next;
4893:     }
4894:   } else {
4895:     while (next) {
4896:       inext = next->handlers;
4897:       while (inext) {
4898:         PetscCall(PetscStrcmp(mtype, inext->mtype, &flg));
4899:         if (flg && inext->createfactor[(int)ftype - 1]) {
4900:           if (foundtype) *foundtype = PETSC_TRUE;
4901:           if (foundmtype) *foundmtype = PETSC_TRUE;
4902:           if (createfactor) *createfactor = inext->createfactor[(int)ftype - 1];
4903:           PetscFunctionReturn(PETSC_SUCCESS);
4904:         }
4905:         inext = inext->next;
4906:       }
4907:       next = next->next;
4908:     }
4909:     /* try with base classes inext->mtype */
4910:     next = MatSolverTypeHolders;
4911:     while (next) {
4912:       inext = next->handlers;
4913:       while (inext) {
4914:         PetscCall(PetscStrbeginswith(mtype, inext->mtype, &flg));
4915:         if (flg && inext->createfactor[(int)ftype - 1]) {
4916:           if (foundtype) *foundtype = PETSC_TRUE;
4917:           if (foundmtype) *foundmtype = PETSC_TRUE;
4918:           if (createfactor) *createfactor = inext->createfactor[(int)ftype - 1];
4919:           PetscFunctionReturn(PETSC_SUCCESS);
4920:         }
4921:         inext = inext->next;
4922:       }
4923:       next = next->next;
4924:     }
4925:   }
4926:   PetscFunctionReturn(PETSC_SUCCESS);
4927: }

4929: PetscErrorCode MatSolverTypeDestroy(void)
4930: {
4931:   MatSolverTypeHolder         next = MatSolverTypeHolders, prev;
4932:   MatSolverTypeForSpecifcType inext, iprev;

4934:   PetscFunctionBegin;
4935:   while (next) {
4936:     PetscCall(PetscFree(next->name));
4937:     inext = next->handlers;
4938:     while (inext) {
4939:       PetscCall(PetscFree(inext->mtype));
4940:       iprev = inext;
4941:       inext = inext->next;
4942:       PetscCall(PetscFree(iprev));
4943:     }
4944:     prev = next;
4945:     next = next->next;
4946:     PetscCall(PetscFree(prev));
4947:   }
4948:   MatSolverTypeHolders = NULL;
4949:   PetscFunctionReturn(PETSC_SUCCESS);
4950: }

4952: static PetscErrorCode MatGetFactor_Private(Mat mat, MatFactorType ftype, PetscBool exact, PetscBool *found, Mat *f)
4953: {
4954:   MatSolverTypeHolder         next = MatSolverTypeHolders;
4955:   MatSolverTypeForSpecifcType inext;
4956:   PetscBool                   flg, same;

4958:   PetscFunctionBegin;
4959:   *found = PETSC_FALSE;
4960:   *f     = NULL;
4961:   /* When no solver type is requested, MatGetFactor() must honor registration order, but a registered
4962:      MatSolverType may only be able to reject a particular MatType at runtime by returning NULL in *f.
4963:      Keep walking the registry until a matching backend actually creates a factor. */
4964:   while (next) {
4965:     inext = next->handlers;
4966:     while (inext) {
4967:       PetscCall(PetscStrcmp(((PetscObject)mat)->type_name, inext->mtype, &same));
4968:       if (exact) flg = same;
4969:       else {
4970:         /* Do the base-type pass separately from the exact pass so exact registrations for the MatType
4971:            are all tried before broader registrations such as implementation base classes. */
4972:         PetscCall(PetscStrbeginswith(((PetscObject)mat)->type_name, inext->mtype, &flg));
4973:         flg = (PetscBool)(flg && !same);
4974:       }
4975:       if (flg && inext->createfactor[(int)ftype - 1]) {
4976:         *found = PETSC_TRUE;
4977:         PetscCall((*inext->createfactor[(int)ftype - 1])(mat, ftype, f));
4978:         if (*f) PetscFunctionReturn(PETSC_SUCCESS);
4979:       }
4980:       inext = inext->next;
4981:     }
4982:     next = next->next;
4983:   }
4984:   PetscFunctionReturn(PETSC_SUCCESS);
4985: }

4987: /*@
4988:   MatFactorGetCanUseOrdering - Indicates if the factorization can use the ordering provided in `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`

4990:   Logically Collective

4992:   Input Parameter:
4993: . mat - the matrix

4995:   Output Parameter:
4996: . flg - `PETSC_TRUE` if uses the ordering

4998:   Level: developer

5000:   Note:
5001:   Most internal PETSc factorizations use the ordering passed to the factorization routine but external
5002:   packages do not, thus we want to skip generating the ordering when it is not needed or used.

5004: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`
5005: @*/
5006: PetscErrorCode MatFactorGetCanUseOrdering(Mat mat, PetscBool *flg)
5007: {
5008:   PetscFunctionBegin;
5009:   *flg = mat->canuseordering;
5010:   PetscFunctionReturn(PETSC_SUCCESS);
5011: }

5013: /*@
5014:   MatFactorGetPreferredOrdering - The preferred ordering for a particular matrix factor object

5016:   Logically Collective

5018:   Input Parameters:
5019: + mat   - the matrix obtained with `MatGetFactor()`
5020: - ftype - the factorization type to be used

5022:   Output Parameter:
5023: . otype - the preferred ordering type

5025:   Level: developer

5027: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatFactorType`, `MatOrderingType`, `MatCopy()`, `MatDuplicate()`, `MatGetFactorAvailable()`, `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`
5028: @*/
5029: PetscErrorCode MatFactorGetPreferredOrdering(Mat mat, MatFactorType ftype, MatOrderingType *otype)
5030: {
5031:   PetscFunctionBegin;
5032:   *otype = mat->preferredordering[ftype];
5033:   PetscCheck(*otype, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MatFactor did not have a preferred ordering");
5034:   PetscFunctionReturn(PETSC_SUCCESS);
5035: }

5037: /*@
5038:   MatGetFactor - Returns a matrix suitable to calls to routines such as `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`, `MatILUFactorSymbolic()`,
5039:   `MatICCFactorSymbolic()`, `MatLUFactorNumeric()`, and `MatCholeskyFactorNumeric()`

5041:   Collective

5043:   Input Parameters:
5044: + mat   - the matrix
5045: . type  - name of solver type, for example, `superlu_dist`, `petsc` (to use PETSc's solver if it is available), if this is `NULL`, then the first result that satisfies
5046:           the other criteria is returned
5047: - ftype - factor type, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`

5049:   Output Parameter:
5050: . f - the factor matrix used with MatXXFactorSymbolic,Numeric() calls. Can be `NULL` in some cases, see notes below.

5052:   Options Database Keys:
5053: + -pc_factor_mat_solver_type type            - choose the type at run time. When using `KSP` solvers
5054: . -pc_factor_mat_factor_on_host (true|false) - do matrix factorization on host (with device matrices). Default is doing it on device
5055: - -pc_factor_mat_solve_on_host (true|false)  - do matrix solve on host (with device matrices). Default is doing it on device

5057:   Level: intermediate

5059:   Notes:
5060:   Some of the packages, such as MUMPS, have options for controlling the factorization, these are in the form `-prefix_mat_packagename_packageoption`
5061:   (for example, `-mat_mumps_icntl_6 1`)  where `prefix` is normally set automatically from the calling `KSP`/`PC`. If `MatGetFactor()` is called directly,
5062:   without using a `PC`, one can set the prefix by
5063:   calling `MatSetOptionsPrefixFactor()` on the originating matrix or  `MatSetOptionsPrefix()` on the resulting factor matrix.

5065:   Some PETSc matrix formats have alternative solvers available that are provided by alternative packages
5066:   such as PaStiX, SuperLU_DIST, MUMPS etc. PETSc must have been configured to use the external solver,
5067:   using the corresponding `./configure` option such as `--download-package` or `--with-package-dir`.

5069:   When `type` is `NULL` the available results are searched for based on the order of the calls to `MatSolverTypeRegister()` in `MatInitializePackage()`.
5070:   Since different PETSc configurations may have different external solvers, seemingly identical runs with different PETSc configurations may use a different solver.
5071:   For example if one configuration had `--download-mumps` while a different one had `--download-superlu_dist`.

5073:   The return matrix can be `NULL` if the requested factorization is not available, since some combinations of matrix types and factorization
5074:   types registered with `MatSolverTypeRegister()` cannot be fully tested if not at runtime.

5076:   Developer Note:
5077:   This should actually be called `MatCreateFactor()` since it creates a new factor object

5079:   The `MatGetFactor()` implementations should not be accessing the PETSc options database or making other decisions about solver options,
5080:   that should be delayed until the later operations. This is to ensure the correct options prefix has been set in the factor matrix.

5082: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `KSP`, `MatSolverType`, `MatFactorType`, `MatCopy()`, `MatDuplicate()`,
5083:           `MatGetFactorAvailable()`, `MatFactorGetCanUseOrdering()`, `MatSolverTypeRegister()`, `MatSolverTypeGet()`,
5084:           `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`, `MatInitializePackage()`,
5085:           `MatLUFactorSymbolic()`, `MatCholeskyFactorSymbolic()`, `MatILUFactorSymbolic()`,
5086:           `MatICCFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactorNumeric()`
5087: @*/
5088: PetscErrorCode MatGetFactor(Mat mat, MatSolverType type, MatFactorType ftype, Mat *f)
5089: {
5090:   PetscBool foundtype, foundmtype, shell, hasop = PETSC_FALSE;
5091:   PetscErrorCode (*conv)(Mat, MatFactorType, Mat *);

5093:   PetscFunctionBegin;

5097:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5098:   MatCheckPreallocated(mat, 1);

5100:   PetscCall(MatIsShell(mat, &shell));
5101:   if (shell) PetscCall(MatHasOperation(mat, MATOP_GET_FACTOR, &hasop));
5102:   if (hasop) {
5103:     PetscUseTypeMethod(mat, getfactor, type, ftype, f);
5104:     PetscFunctionReturn(PETSC_SUCCESS);
5105:   }

5107:   if (!type) {
5108:     PetscBool foundbase;

5110:     /* First try exact MatType registrations in solver registration order. If all matching backends
5111:        decline this matrix instance by returning NULL, then try base-type registrations. */
5112:     PetscCall(MatGetFactor_Private(mat, ftype, PETSC_TRUE, &foundtype, f));
5113:     if (!*f) {
5114:       PetscCall(MatGetFactor_Private(mat, ftype, PETSC_FALSE, &foundbase, f));
5115:       foundtype = (PetscBool)(foundtype || foundbase);
5116:     }
5117:     PetscCheck(foundtype, PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "Could not locate a solver type for factorization type %s and matrix type %s.", MatFactorTypes[ftype], ((PetscObject)mat)->type_name);
5118:     if (mat->factorprefix) PetscCall(MatSetOptionsPrefix(*f, mat->factorprefix));
5119:     PetscFunctionReturn(PETSC_SUCCESS);
5120:   }

5122:   PetscCall(MatSolverTypeGet(type, ((PetscObject)mat)->type_name, ftype, &foundtype, &foundmtype, &conv));
5123:   PetscCheck(foundtype, PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "Could not locate%s solver type%s%s for factorization type %s and matrix type %s.%s%s", !type ? " a" : "", type ? " " : "", type ? type : "", MatFactorTypes[ftype],
5124:              ((PetscObject)mat)->type_name, type ? " Perhaps you must ./configure with --download-" : "", type ? type : "");
5125:   PetscCheck(foundmtype, PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "MatSolverType %s does not support matrix type %s", type, ((PetscObject)mat)->type_name);
5126:   PetscCheck(conv, PetscObjectComm((PetscObject)mat), PETSC_ERR_MISSING_FACTOR, "MatSolverType %s does not support factorization type %s for matrix type %s", type, MatFactorTypes[ftype], ((PetscObject)mat)->type_name);

5128:   PetscCall((*conv)(mat, ftype, f));
5129:   if (mat->factorprefix) PetscCall(MatSetOptionsPrefix(*f, mat->factorprefix));
5130:   PetscFunctionReturn(PETSC_SUCCESS);
5131: }

5133: /*@
5134:   MatGetFactorAvailable - Returns a flag if matrix supports particular type and factor type

5136:   Not Collective

5138:   Input Parameters:
5139: + mat   - the matrix
5140: . type  - name of solver type, for example, `superlu`, `petsc` (to use PETSc's default)
5141: - ftype - factor type, `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`

5143:   Output Parameter:
5144: . flg - `PETSC_TRUE` if the factorization is available

5146:   Level: intermediate

5148:   Notes:
5149:   Some PETSc matrix formats have alternative solvers available that are contained in alternative packages
5150:   such as `pastix`, `superlu`, `mumps`, etc.

5152:   PETSc must have been configured with `./configure` to use the external solver using the option `--download-package` where package is the name of the package

5154:   Developer Note:
5155:   This should actually be called `MatCreateFactorAvailable()` since `MatGetFactor()` creates a new factor object

5157: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatSolverType`, `MatFactorType`, `MatGetFactor()`, `MatCopy()`, `MatDuplicate()`, `MatSolverTypeRegister()`,
5158:           `MAT_FACTOR_LU`, `MAT_FACTOR_CHOLESKY`, `MAT_FACTOR_ICC`, `MAT_FACTOR_ILU`, `MAT_FACTOR_QR`, `MatSolverTypeGet()`
5159: @*/
5160: PetscErrorCode MatGetFactorAvailable(Mat mat, MatSolverType type, MatFactorType ftype, PetscBool *flg)
5161: {
5162:   PetscErrorCode (*gconv)(Mat, MatFactorType, Mat *);

5164:   PetscFunctionBegin;
5166:   PetscAssertPointer(flg, 4);

5168:   *flg = PETSC_FALSE;
5169:   if (!((PetscObject)mat)->type_name) PetscFunctionReturn(PETSC_SUCCESS);

5171:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5172:   MatCheckPreallocated(mat, 1);

5174:   PetscCall(MatSolverTypeGet(type, ((PetscObject)mat)->type_name, ftype, NULL, NULL, &gconv));
5175:   *flg = gconv ? PETSC_TRUE : PETSC_FALSE;
5176:   PetscFunctionReturn(PETSC_SUCCESS);
5177: }

5179: /*@
5180:   MatDuplicate - Duplicates a matrix including the non-zero structure.

5182:   Collective

5184:   Input Parameters:
5185: + mat - the matrix
5186: - op  - One of `MAT_DO_NOT_COPY_VALUES`, `MAT_COPY_VALUES`, or `MAT_SHARE_NONZERO_PATTERN`.
5187:         See the manual page for `MatDuplicateOption()` for an explanation of these options.

5189:   Output Parameter:
5190: . M - pointer to place new matrix

5192:   Level: intermediate

5194:   Notes:
5195:   You cannot change the nonzero pattern for the parent or child matrix later if you use `MAT_SHARE_NONZERO_PATTERN`.

5197:   If `op` is not `MAT_COPY_VALUES` the numerical values in the new matrix are zeroed.

5199:   May be called with an unassembled input `Mat` if `MAT_DO_NOT_COPY_VALUES` is used, in which case the output `Mat` is unassembled as well.

5201:   When original mat is a product of matrix operation, e.g., an output of `MatMatMult()` or `MatCreateSubMatrix()`, only the matrix data structure of `mat`
5202:   is duplicated and the internal data structures created for the reuse of previous matrix operations are not duplicated.
5203:   User should not use `MatDuplicate()` to create new matrix `M` if `M` is intended to be reused as the product of matrix operation.

5205: .seealso: [](ch_matrices), `Mat`, `MatCopy()`, `MatConvert()`, `MatDuplicateOption`
5206: @*/
5207: PetscErrorCode MatDuplicate(Mat mat, MatDuplicateOption op, Mat *M)
5208: {
5209:   Mat               B;
5210:   VecType           vtype;
5211:   PetscInt          i;
5212:   PetscObject       dm, container_h, container_d;
5213:   PetscErrorCodeFn *viewf;

5215:   PetscFunctionBegin;
5218:   PetscAssertPointer(M, 3);
5219:   PetscCheck(op != MAT_COPY_VALUES || mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MAT_COPY_VALUES not allowed for unassembled matrix");
5220:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5221:   MatCheckPreallocated(mat, 1);

5223:   PetscCall(PetscLogEventBegin(MAT_Convert, mat, 0, 0, 0));
5224:   PetscUseTypeMethod(mat, duplicate, op, M);
5225:   PetscCall(PetscLogEventEnd(MAT_Convert, mat, 0, 0, 0));
5226:   B = *M;

5228:   PetscCall(MatGetOperation(mat, MATOP_VIEW, &viewf));
5229:   if (viewf) PetscCall(MatSetOperation(B, MATOP_VIEW, viewf));
5230:   PetscCall(MatGetVecType(mat, &vtype));
5231:   PetscCall(MatSetVecType(B, vtype));

5233:   B->stencil.dim = mat->stencil.dim;
5234:   B->stencil.noc = mat->stencil.noc;
5235:   for (i = 0; i <= mat->stencil.dim + (mat->stencil.noc ? 0 : -1); i++) {
5236:     B->stencil.dims[i]   = mat->stencil.dims[i];
5237:     B->stencil.starts[i] = mat->stencil.starts[i];
5238:   }

5240:   B->nooffproczerorows = mat->nooffproczerorows;
5241:   B->nooffprocentries  = mat->nooffprocentries;
5242:   B->nonzerostate      = mat->nonzerostate;

5244:   PetscCall(PetscObjectQuery((PetscObject)mat, "__PETSc_dm", &dm));
5245:   if (dm) PetscCall(PetscObjectCompose((PetscObject)B, "__PETSc_dm", dm));
5246:   PetscCall(PetscObjectQuery((PetscObject)mat, "__PETSc_MatCOOStruct_Host", &container_h));
5247:   if (container_h) PetscCall(PetscObjectCompose((PetscObject)B, "__PETSc_MatCOOStruct_Host", container_h));
5248:   PetscCall(PetscObjectQuery((PetscObject)mat, "__PETSc_MatCOOStruct_Device", &container_d));
5249:   if (container_d) PetscCall(PetscObjectCompose((PetscObject)B, "__PETSc_MatCOOStruct_Device", container_d));
5250:   if (op == MAT_COPY_VALUES) PetscCall(MatPropagateSymmetryOptions(mat, B));
5251:   PetscCall(PetscObjectStateIncrease((PetscObject)B));
5252:   PetscFunctionReturn(PETSC_SUCCESS);
5253: }

5255: /*@
5256:   MatGetDiagonal - Gets the diagonal of a matrix as a `Vec`

5258:   Logically Collective

5260:   Input Parameter:
5261: . mat - the matrix

5263:   Output Parameter:
5264: . v - the diagonal of the matrix

5266:   Level: intermediate

5268:   Note:
5269:   If `mat` has local sizes `n` x `m`, this routine fills the first `ndiag = min(n, m)` entries
5270:   of `v` with the diagonal values. Thus `v` must have local size of at least `ndiag`. If `v`
5271:   is larger than `ndiag`, the values of the remaining entries are unspecified.

5273:   Currently only correct in parallel for square matrices.

5275: .seealso: [](ch_matrices), `Mat`, `Vec`, `MatGetRow()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMaxAbs()`
5276: @*/
5277: PetscErrorCode MatGetDiagonal(Mat mat, Vec v)
5278: {
5279:   PetscFunctionBegin;
5283:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5284:   MatCheckPreallocated(mat, 1);
5285:   if (PetscDefined(USE_DEBUG)) {
5286:     PetscInt nv, row, col, ndiag;

5288:     PetscCall(VecGetLocalSize(v, &nv));
5289:     PetscCall(MatGetLocalSize(mat, &row, &col));
5290:     ndiag = PetscMin(row, col);
5291:     PetscCheck(nv >= ndiag, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Nonconforming Mat and Vec. Vec local size %" PetscInt_FMT " < Mat local diagonal length %" PetscInt_FMT, nv, ndiag);
5292:   }

5294:   PetscUseTypeMethod(mat, getdiagonal, v);
5295:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5296:   PetscFunctionReturn(PETSC_SUCCESS);
5297: }

5299: /*@
5300:   MatGetRowMin - Gets the minimum value (of the real part) of each
5301:   row of the matrix

5303:   Logically Collective

5305:   Input Parameter:
5306: . mat - the matrix

5308:   Output Parameters:
5309: + v   - the vector for storing the maximums
5310: - idx - the indices of the column found for each row (optional, pass `NULL` if not needed)

5312:   Level: intermediate

5314:   Note:
5315:   The result of this call are the same as if one converted the matrix to dense format
5316:   and found the minimum value in each row (i.e. the implicit zeros are counted as zeros).

5318:   This code is only implemented for a couple of matrix formats.

5320: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMaxAbs()`, `MatGetRowMinAbs()`,
5321:           `MatGetRowMax()`
5322: @*/
5323: PetscErrorCode MatGetRowMin(Mat mat, Vec v, PetscInt idx[])
5324: {
5325:   PetscFunctionBegin;
5329:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5331:   if (!mat->cmap->N) {
5332:     PetscCall(VecSet(v, PETSC_MAX_REAL));
5333:     if (idx) {
5334:       PetscInt i, m = mat->rmap->n;
5335:       for (i = 0; i < m; i++) idx[i] = -1;
5336:     }
5337:   } else {
5338:     MatCheckPreallocated(mat, 1);
5339:   }
5340:   PetscUseTypeMethod(mat, getrowmin, v, idx);
5341:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5342:   PetscFunctionReturn(PETSC_SUCCESS);
5343: }

5345: /*@
5346:   MatGetRowMinAbs - Gets the minimum value (in absolute value) of each
5347:   row of the matrix

5349:   Logically Collective

5351:   Input Parameter:
5352: . mat - the matrix

5354:   Output Parameters:
5355: + v   - the vector for storing the minimums
5356: - idx - the indices of the column found for each row (or `NULL` if not needed)

5358:   Level: intermediate

5360:   Notes:
5361:   if a row is completely empty or has only 0.0 values, then the `idx` value for that
5362:   row is 0 (the first column).

5364:   This code is only implemented for a couple of matrix formats.

5366: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMax()`, `MatGetRowMaxAbs()`, `MatGetRowMin()`
5367: @*/
5368: PetscErrorCode MatGetRowMinAbs(Mat mat, Vec v, PetscInt idx[])
5369: {
5370:   PetscFunctionBegin;
5374:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5375:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

5377:   if (!mat->cmap->N) {
5378:     PetscCall(VecSet(v, 0.0));
5379:     if (idx) {
5380:       PetscInt i, m = mat->rmap->n;
5381:       for (i = 0; i < m; i++) idx[i] = -1;
5382:     }
5383:   } else {
5384:     MatCheckPreallocated(mat, 1);
5385:     if (idx) PetscCall(PetscArrayzero(idx, mat->rmap->n));
5386:     PetscUseTypeMethod(mat, getrowminabs, v, idx);
5387:   }
5388:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5389:   PetscFunctionReturn(PETSC_SUCCESS);
5390: }

5392: /*@
5393:   MatGetRowMax - Gets the maximum value (of the real part) of each
5394:   row of the matrix

5396:   Logically Collective

5398:   Input Parameter:
5399: . mat - the matrix

5401:   Output Parameters:
5402: + v   - the vector for storing the maximums
5403: - idx - the indices of the column found for each row (optional, otherwise pass `NULL`)

5405:   Level: intermediate

5407:   Notes:
5408:   The result of this call are the same as if one converted the matrix to dense format
5409:   and found the minimum value in each row (i.e. the implicit zeros are counted as zeros).

5411:   This code is only implemented for a couple of matrix formats.

5413: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMaxAbs()`, `MatGetRowMin()`, `MatGetRowMinAbs()`
5414: @*/
5415: PetscErrorCode MatGetRowMax(Mat mat, Vec v, PetscInt idx[])
5416: {
5417:   PetscFunctionBegin;
5421:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5423:   if (!mat->cmap->N) {
5424:     PetscCall(VecSet(v, PETSC_MIN_REAL));
5425:     if (idx) {
5426:       PetscInt i, m = mat->rmap->n;
5427:       for (i = 0; i < m; i++) idx[i] = -1;
5428:     }
5429:   } else {
5430:     MatCheckPreallocated(mat, 1);
5431:     PetscUseTypeMethod(mat, getrowmax, v, idx);
5432:   }
5433:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5434:   PetscFunctionReturn(PETSC_SUCCESS);
5435: }

5437: /*@
5438:   MatGetRowMaxAbs - Gets the maximum value (in absolute value) of each
5439:   row of the matrix

5441:   Logically Collective

5443:   Input Parameter:
5444: . mat - the matrix

5446:   Output Parameters:
5447: + v   - the vector for storing the maximums
5448: - idx - the indices of the column found for each row (or `NULL` if not needed)

5450:   Level: intermediate

5452:   Notes:
5453:   if a row is completely empty or has only 0.0 values, then the `idx` value for that
5454:   row is 0 (the first column).

5456:   This code is only implemented for a couple of matrix formats.

5458: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowSum()`, `MatGetRowMin()`, `MatGetRowMinAbs()`
5459: @*/
5460: PetscErrorCode MatGetRowMaxAbs(Mat mat, Vec v, PetscInt idx[])
5461: {
5462:   PetscFunctionBegin;
5466:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5468:   if (!mat->cmap->N) {
5469:     PetscCall(VecSet(v, 0.0));
5470:     if (idx) {
5471:       PetscInt i, m = mat->rmap->n;
5472:       for (i = 0; i < m; i++) idx[i] = -1;
5473:     }
5474:   } else {
5475:     MatCheckPreallocated(mat, 1);
5476:     if (idx) PetscCall(PetscArrayzero(idx, mat->rmap->n));
5477:     PetscUseTypeMethod(mat, getrowmaxabs, v, idx);
5478:   }
5479:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5480:   PetscFunctionReturn(PETSC_SUCCESS);
5481: }

5483: /*@
5484:   MatGetRowSumAbs - Gets the sum value (in absolute value) of each row of the matrix

5486:   Logically Collective

5488:   Input Parameter:
5489: . mat - the matrix

5491:   Output Parameter:
5492: . v - the vector for storing the sum

5494:   Level: intermediate

5496:   This code is only implemented for a couple of matrix formats.

5498: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMax()`, `MatGetRowMin()`, `MatGetRowMinAbs()`
5499: @*/
5500: PetscErrorCode MatGetRowSumAbs(Mat mat, Vec v)
5501: {
5502:   PetscFunctionBegin;
5506:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");

5508:   if (!mat->cmap->N) PetscCall(VecSet(v, 0.0));
5509:   else {
5510:     MatCheckPreallocated(mat, 1);
5511:     PetscUseTypeMethod(mat, getrowsumabs, v);
5512:   }
5513:   PetscCall(PetscObjectStateIncrease((PetscObject)v));
5514:   PetscFunctionReturn(PETSC_SUCCESS);
5515: }

5517: /*@
5518:   MatGetRowSum - Gets the sum of each row of the matrix

5520:   Logically or Neighborhood Collective

5522:   Input Parameter:
5523: . mat - the matrix

5525:   Output Parameter:
5526: . v - the vector for storing the sum of rows

5528:   Level: intermediate

5530:   Note:
5531:   This code is slow since it is not currently specialized for different formats

5533: .seealso: [](ch_matrices), `Mat`, `MatGetDiagonal()`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRowMax()`, `MatGetRowMin()`, `MatGetRowMaxAbs()`, `MatGetRowMinAbs()`, `MatGetRowSumAbs()`
5534: @*/
5535: PetscErrorCode MatGetRowSum(Mat mat, Vec v)
5536: {
5537:   Vec ones;

5539:   PetscFunctionBegin;
5543:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5544:   MatCheckPreallocated(mat, 1);
5545:   PetscCall(MatCreateVecs(mat, &ones, NULL));
5546:   PetscCall(VecSet(ones, 1.));
5547:   PetscCall(MatMult(mat, ones, v));
5548:   PetscCall(VecDestroy(&ones));
5549:   PetscFunctionReturn(PETSC_SUCCESS);
5550: }

5552: /*@
5553:   MatTransposeSetPrecursor - Set the matrix from which the second matrix will receive numerical transpose data with a call to `MatTranspose`(A,`MAT_REUSE_MATRIX`,&B)
5554:   when B was not obtained with `MatTranspose`(A,`MAT_INITIAL_MATRIX`,&B)

5556:   Collective

5558:   Input Parameter:
5559: . mat - the matrix to provide the transpose

5561:   Output Parameter:
5562: . B - the matrix to contain the transpose; it MUST have the nonzero structure of the transpose of A or the code will crash or generate incorrect results

5564:   Level: advanced

5566:   Note:
5567:   Normally the use of `MatTranspose`(A, `MAT_REUSE_MATRIX`, &B) requires that `B` was obtained with a call to `MatTranspose`(A, `MAT_INITIAL_MATRIX`, &B). This
5568:   routine allows bypassing that call.

5570: .seealso: [](ch_matrices), `Mat`, `MatTransposeSymbolic()`, `MatTranspose()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`
5571: @*/
5572: PetscErrorCode MatTransposeSetPrecursor(Mat mat, Mat B)
5573: {
5574:   MatState *rb = NULL;

5576:   PetscFunctionBegin;
5577:   PetscCall(PetscNew(&rb));
5578:   rb->id    = ((PetscObject)mat)->id;
5579:   rb->state = 0;
5580:   PetscCall(MatGetNonzeroState(mat, &rb->nonzerostate));
5581:   PetscCall(PetscObjectContainerCompose((PetscObject)B, "MatTransposeParent", rb, PetscCtxDestroyDefault));
5582:   PetscFunctionReturn(PETSC_SUCCESS);
5583: }

5585: static PetscErrorCode MatTranspose_Private(Mat mat, MatReuse reuse, Mat *B, PetscBool conjugate)
5586: {
5587:   PetscContainer rB                         = NULL;
5588:   MatState      *rb                         = NULL;
5589:   PetscErrorCode (*f)(Mat, MatReuse, Mat *) = NULL;

5591:   PetscFunctionBegin;
5594:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5595:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5596:   PetscCheck(reuse != MAT_INPLACE_MATRIX || mat == *B, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "MAT_INPLACE_MATRIX requires last matrix to match first");
5597:   PetscCheck(reuse != MAT_REUSE_MATRIX || mat != *B, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Perhaps you mean MAT_INPLACE_MATRIX");
5598:   MatCheckPreallocated(mat, 1);
5599:   if (reuse == MAT_REUSE_MATRIX) {
5600:     PetscCall(PetscObjectQuery((PetscObject)*B, "MatTransposeParent", (PetscObject *)&rB));
5601:     PetscCheck(rB, PetscObjectComm((PetscObject)*B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from call to MatTranspose(). Suggest MatTransposeSetPrecursor().");
5602:     PetscCall(PetscContainerGetPointer(rB, &rb));
5603:     PetscCheck(rb->id == ((PetscObject)mat)->id, PetscObjectComm((PetscObject)*B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from input matrix");
5604:     if (rb->state == ((PetscObject)mat)->state) PetscFunctionReturn(PETSC_SUCCESS);
5605:   }

5607:   if (conjugate) {
5608:     f = mat->ops->hermitiantranspose;
5609:     if (f) PetscCall((*f)(mat, reuse, B));
5610:   }
5611:   if (!f && !(reuse == MAT_INPLACE_MATRIX && mat->hermitian == PETSC_BOOL3_TRUE && conjugate)) {
5612:     PetscCall(PetscLogEventBegin(MAT_Transpose, mat, 0, 0, 0));
5613:     if (reuse != MAT_INPLACE_MATRIX || mat->symmetric != PETSC_BOOL3_TRUE) {
5614:       PetscUseTypeMethod(mat, transpose, reuse, B);
5615:       PetscCall(PetscObjectStateIncrease((PetscObject)*B));
5616:     }
5617:     PetscCall(PetscLogEventEnd(MAT_Transpose, mat, 0, 0, 0));
5618:     if (conjugate) PetscCall(MatConjugate(*B));
5619:   }

5621:   if (reuse == MAT_INITIAL_MATRIX) PetscCall(MatTransposeSetPrecursor(mat, *B));
5622:   if (reuse != MAT_INPLACE_MATRIX) {
5623:     PetscCall(PetscObjectQuery((PetscObject)*B, "MatTransposeParent", (PetscObject *)&rB));
5624:     PetscCall(PetscContainerGetPointer(rB, &rb));
5625:     rb->state        = ((PetscObject)mat)->state;
5626:     rb->nonzerostate = mat->nonzerostate;
5627:   }
5628:   PetscFunctionReturn(PETSC_SUCCESS);
5629: }

5631: /*@
5632:   MatTranspose - Computes the transpose of a matrix, either in-place or out-of-place.

5634:   Collective

5636:   Input Parameters:
5637: + mat   - the matrix to transpose
5638: - reuse - either `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, or `MAT_INPLACE_MATRIX`

5640:   Output Parameter:
5641: . B - the transpose of the matrix

5643:   Level: intermediate

5645:   Notes:
5646:   If you use `MAT_INPLACE_MATRIX` then you must pass in `&mat` for `B`

5648:   `MAT_REUSE_MATRIX` uses the `B` matrix obtained from a previous call to this function with `MAT_INITIAL_MATRIX` to store the transpose. If you already have a matrix to contain the
5649:   transpose, call `MatTransposeSetPrecursor(mat, B)` before calling this routine.

5651:   If the nonzero structure of `mat` changed from the previous call to this function with the same matrices an error will be generated for some matrix types.

5653:   Consider using `MatCreateTranspose()` instead if you only need a matrix that behaves like the transpose but don't need the storage to be changed.
5654:   For example, the result of `MatCreateTranspose()` will compute the transpose of the given matrix times a vector for matrix-vector products computed with `MatMult()`.

5656:   If `mat` is unchanged from the last call this function returns immediately without recomputing the result

5658:   If you only need the symbolic transpose of a matrix, and not the numerical values, use `MatTransposeSymbolic()`

5660: .seealso: [](ch_matrices), `Mat`, `MatTransposeSetPrecursor()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`,
5661:           `MatTransposeSymbolic()`, `MatCreateTranspose()`
5662: @*/
5663: PetscErrorCode MatTranspose(Mat mat, MatReuse reuse, Mat *B)
5664: {
5665:   PetscFunctionBegin;
5666:   PetscCall(MatTranspose_Private(mat, reuse, B, PETSC_FALSE));
5667:   PetscFunctionReturn(PETSC_SUCCESS);
5668: }

5670: /*@
5671:   MatTransposeSymbolic - Computes the symbolic part of the transpose of a matrix.

5673:   Collective

5675:   Input Parameter:
5676: . A - the matrix to transpose

5678:   Output Parameter:
5679: . B - the transpose. This is a complete matrix but the numerical portion is invalid. One can call `MatTranspose`(A,`MAT_REUSE_MATRIX`,&B) to compute the
5680:       numerical portion.

5682:   Level: intermediate

5684:   Note:
5685:   This is not supported for many matrix types, use `MatTranspose()` in those cases

5687: .seealso: [](ch_matrices), `Mat`, `MatTransposeSetPrecursor()`, `MatTranspose()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`, `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, `MAT_INPLACE_MATRIX`
5688: @*/
5689: PetscErrorCode MatTransposeSymbolic(Mat A, Mat *B)
5690: {
5691:   PetscFunctionBegin;
5694:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5695:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5696:   PetscCall(PetscLogEventBegin(MAT_Transpose, A, 0, 0, 0));
5697:   PetscUseTypeMethod(A, transposesymbolic, B);
5698:   PetscCall(PetscLogEventEnd(MAT_Transpose, A, 0, 0, 0));

5700:   PetscCall(MatTransposeSetPrecursor(A, *B));
5701:   PetscFunctionReturn(PETSC_SUCCESS);
5702: }

5704: PetscErrorCode MatTransposeCheckNonzeroState_Private(Mat A, Mat B)
5705: {
5706:   PetscContainer rB;
5707:   MatState      *rb;

5709:   PetscFunctionBegin;
5712:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5713:   PetscCheck(!A->factortype, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5714:   PetscCall(PetscObjectQuery((PetscObject)B, "MatTransposeParent", (PetscObject *)&rB));
5715:   PetscCheck(rB, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from call to MatTranspose()");
5716:   PetscCall(PetscContainerGetPointer(rB, &rb));
5717:   PetscCheck(rb->id == ((PetscObject)A)->id, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONG, "Reuse matrix used was not generated from input matrix");
5718:   PetscCheck(rb->nonzerostate == A->nonzerostate, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONGSTATE, "Reuse matrix has changed nonzero structure");
5719:   PetscFunctionReturn(PETSC_SUCCESS);
5720: }

5722: /*@
5723:   MatIsTranspose - Test whether a matrix is another one's transpose,
5724:   or its own, in which case it tests symmetry.

5726:   Collective

5728:   Input Parameters:
5729: + A   - the matrix to test
5730: . B   - the matrix to test against, this can equal the first parameter
5731: - tol - tolerance, differences between entries smaller than this are counted as zero

5733:   Output Parameter:
5734: . flg - the result

5736:   Level: intermediate

5738:   Notes:
5739:   The sequential algorithm has a running time of the order of the number of nonzeros; the parallel
5740:   test involves parallel copies of the block off-diagonal parts of the matrix.

5742: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsSymmetric()`, `MatIsHermitian()`
5743: @*/
5744: PetscErrorCode MatIsTranspose(Mat A, Mat B, PetscReal tol, PetscBool *flg)
5745: {
5746:   PetscErrorCode (*f)(Mat, Mat, PetscReal, PetscBool *), (*g)(Mat, Mat, PetscReal, PetscBool *);

5748:   PetscFunctionBegin;
5751:   PetscAssertPointer(flg, 4);
5752:   PetscCall(PetscObjectQueryFunction((PetscObject)A, "MatIsTranspose_C", &f));
5753:   PetscCall(PetscObjectQueryFunction((PetscObject)B, "MatIsTranspose_C", &g));
5754:   *flg = PETSC_FALSE;
5755:   if (f && g) {
5756:     PetscCheck(f == g, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_NOTSAMETYPE, "Matrices do not have the same comparator for symmetry test");
5757:     PetscCall((*f)(A, B, tol, flg));
5758:   } else {
5759:     MatType mattype;

5761:     PetscCall(MatGetType(f ? B : A, &mattype));
5762:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Matrix of type %s does not support checking for transpose", mattype);
5763:   }
5764:   PetscFunctionReturn(PETSC_SUCCESS);
5765: }

5767: /*@
5768:   MatHermitianTranspose - Computes an in-place or out-of-place Hermitian transpose of a matrix in complex conjugate.

5770:   Collective

5772:   Input Parameters:
5773: + mat   - the matrix to transpose and complex conjugate
5774: - reuse - either `MAT_INITIAL_MATRIX`, `MAT_REUSE_MATRIX`, or `MAT_INPLACE_MATRIX`

5776:   Output Parameter:
5777: . B - the Hermitian transpose

5779:   Level: intermediate

5781: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatMultTranspose()`, `MatMultTransposeAdd()`, `MatIsTranspose()`, `MatReuse`
5782: @*/
5783: PetscErrorCode MatHermitianTranspose(Mat mat, MatReuse reuse, Mat *B)
5784: {
5785:   PetscFunctionBegin;
5786:   PetscCall(MatTranspose_Private(mat, reuse, B, PetscDefined(USE_COMPLEX) ? PETSC_TRUE : PETSC_FALSE));
5787:   PetscFunctionReturn(PETSC_SUCCESS);
5788: }

5790: /*@
5791:   MatIsHermitianTranspose - Test whether a matrix is another one's Hermitian transpose,

5793:   Collective

5795:   Input Parameters:
5796: + A   - the matrix to test
5797: . B   - the matrix to test against, this can equal the first parameter
5798: - tol - tolerance, differences between entries smaller than this are counted as zero

5800:   Output Parameter:
5801: . flg - the result

5803:   Level: intermediate

5805:   Notes:
5806:   Only available for `MATAIJ` matrices.

5808:   The sequential algorithm
5809:   has a running time of the order of the number of nonzeros; the parallel
5810:   test involves parallel copies of the block off-diagonal parts of the matrix.

5812: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsSymmetric()`, `MatIsHermitian()`, `MatIsTranspose()`
5813: @*/
5814: PetscErrorCode MatIsHermitianTranspose(Mat A, Mat B, PetscReal tol, PetscBool *flg)
5815: {
5816:   PetscErrorCode (*f)(Mat, Mat, PetscReal, PetscBool *), (*g)(Mat, Mat, PetscReal, PetscBool *);

5818:   PetscFunctionBegin;
5821:   PetscAssertPointer(flg, 4);
5822:   PetscCall(PetscObjectQueryFunction((PetscObject)A, "MatIsHermitianTranspose_C", &f));
5823:   PetscCall(PetscObjectQueryFunction((PetscObject)B, "MatIsHermitianTranspose_C", &g));
5824:   if (f && g) {
5825:     PetscCheck(f == g, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_NOTSAMETYPE, "Matrices do not have the same comparator for Hermitian test");
5826:     PetscCall((*f)(A, B, tol, flg));
5827:   } else {
5828:     MatType mattype;

5830:     PetscCall(MatGetType(f ? B : A, &mattype));
5831:     SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Matrix of type %s does not support checking for Hermitian transpose", mattype);
5832:   }
5833:   PetscFunctionReturn(PETSC_SUCCESS);
5834: }

5836: /*@
5837:   MatPermute - Creates a new matrix with rows and columns permuted from the
5838:   original.

5840:   Collective

5842:   Input Parameters:
5843: + mat - the matrix to permute
5844: . row - row permutation, each process supplies only the permutation for its rows
5845: - col - column permutation, each process supplies only the permutation for its columns

5847:   Output Parameter:
5848: . B - the permuted matrix

5850:   Level: advanced

5852:   Note:
5853:   The index sets map from `row`/`col` of permuted matrix to `row`/`col` of original matrix.
5854:   The index sets should be on the same communicator as mat and have the same local sizes.
5855:   `MATSEQSBAIJ` inputs may produce a `MATSEQBAIJ` matrix when the permutation does not preserve symmetry.

5857:   Developer Note:
5858:   If you want to implement `MatPermute()` for a matrix type, and your approach doesn't
5859:   exploit the fact that `row` and `col` are permutations, consider implementing the
5860:   more general `MatCreateSubMatrix()` instead.

5862: .seealso: [](ch_matrices), `Mat`, `MatGetOrdering()`, `ISAllGather()`, `MatCreateSubMatrix()`
5863: @*/
5864: PetscErrorCode MatPermute(Mat mat, IS row, IS col, Mat *B)
5865: {
5866:   PetscFunctionBegin;
5871:   PetscAssertPointer(B, 4);
5872:   PetscCheckSameComm(mat, 1, row, 2);
5873:   if (row != col) PetscCheckSameComm(row, 2, col, 3);
5874:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5875:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5876:   PetscCheck(mat->ops->permute || mat->ops->createsubmatrix, PETSC_COMM_SELF, PETSC_ERR_SUP, "MatPermute not available for Mat type %s", ((PetscObject)mat)->type_name);
5877:   MatCheckPreallocated(mat, 1);

5879:   if (mat->ops->permute) {
5880:     PetscUseTypeMethod(mat, permute, row, col, B);
5881:     PetscCall(PetscObjectStateIncrease((PetscObject)*B));
5882:   } else {
5883:     PetscCall(MatCreateSubMatrix(mat, row, col, MAT_INITIAL_MATRIX, B));
5884:   }
5885:   PetscFunctionReturn(PETSC_SUCCESS);
5886: }

5888: /*@
5889:   MatEqual - Compares two matrices.

5891:   Collective

5893:   Input Parameters:
5894: + A - the first matrix
5895: - B - the second matrix

5897:   Output Parameter:
5898: . flg - `PETSC_TRUE` if the matrices are equal; `PETSC_FALSE` otherwise.

5900:   Level: intermediate

5902:   Note:
5903:   If either of the matrix is "matrix-free", meaning the matrix entries are not stored explicitly then equality is determined by comparing
5904:   the results of several matrix-vector product using randomly created vectors, see `MatMultEqual()`.

5906: .seealso: [](ch_matrices), `Mat`, `MatMultEqual()`
5907: @*/
5908: PetscErrorCode MatEqual(Mat A, Mat B, PetscBool *flg)
5909: {
5910:   PetscFunctionBegin;
5915:   PetscAssertPointer(flg, 3);
5916:   PetscCheckSameComm(A, 1, B, 2);
5917:   MatCheckPreallocated(A, 1);
5918:   MatCheckPreallocated(B, 2);
5919:   PetscCheck(A->assembled, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5920:   PetscCheck(B->assembled, PetscObjectComm((PetscObject)B), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5921:   PetscCheck(A->rmap->N == B->rmap->N && A->cmap->N == B->cmap->N, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Mat A,Mat B: global dim %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT " %" PetscInt_FMT, A->rmap->N, B->rmap->N, A->cmap->N,
5922:              B->cmap->N);
5923:   if (A->ops->equal && A->ops->equal == B->ops->equal) PetscUseTypeMethod(A, equal, B, flg);
5924:   else PetscCall(MatMultEqual(A, B, 10, flg));
5925:   PetscFunctionReturn(PETSC_SUCCESS);
5926: }

5928: /*@
5929:   MatDiagonalScale - Scales a matrix on the left and right by diagonal
5930:   matrices that are stored as vectors. Either of the two scaling
5931:   matrices can be `NULL`.

5933:   Collective

5935:   Input Parameters:
5936: + mat - the matrix to be scaled
5937: . l   - the left scaling vector (or `NULL`)
5938: - r   - the right scaling vector (or `NULL`)

5940:   Level: intermediate

5942:   Note:
5943:   `MatDiagonalScale()` computes $A = LAR$, where
5944:   L = a diagonal matrix (stored as a vector), R = a diagonal matrix (stored as a vector)
5945:   The L scales the rows of the matrix, the R scales the columns of the matrix.
5946:   For `MATSEQSBAIJ`, if `l` and `r` are different `Vec` objects, `mat` changes to type `MATSEQBAIJ` because the result is not necessarily symmetric.

5948: .seealso: [](ch_matrices), `Mat`, `MatScale()`, `MatShift()`, `MatDiagonalSet()`
5949: @*/
5950: PetscErrorCode MatDiagonalScale(Mat mat, Vec l, Vec r)
5951: {
5952:   PetscBool flg = PETSC_FALSE;

5954:   PetscFunctionBegin;
5957:   if (l) {
5959:     PetscCheckSameComm(mat, 1, l, 2);
5960:   }
5961:   if (r) {
5963:     PetscCheckSameComm(mat, 1, r, 3);
5964:   }
5965:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
5966:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
5967:   MatCheckPreallocated(mat, 1);
5968:   if (!l && !r) PetscFunctionReturn(PETSC_SUCCESS);

5970:   PetscCall(PetscLogEventBegin(MAT_Scale, mat, 0, 0, 0));
5971:   PetscUseTypeMethod(mat, diagonalscale, l, r);
5972:   PetscCall(PetscLogEventEnd(MAT_Scale, mat, 0, 0, 0));
5973:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
5974:   if (l != r && (PetscBool3ToBool(mat->symmetric) || PetscBool3ToBool(mat->hermitian))) {
5975:     if (!PetscDefined(USE_COMPLEX) || PetscBool3ToBool(mat->symmetric)) {
5976:       if (l && r) PetscCall(VecEqual(l, r, &flg));
5977:       if (!flg) {
5978:         PetscCall(PetscObjectTypeCompare((PetscObject)mat, MATMPISBAIJ, &flg));
5979:         PetscCheck(!flg, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "For MATMPISBAIJ, left and right scaling vectors must be the same");
5980:         mat->symmetric = mat->spd = PETSC_BOOL3_FALSE;
5981:         if (!PetscDefined(USE_COMPLEX)) mat->hermitian = PETSC_BOOL3_FALSE;
5982:         else mat->hermitian = PETSC_BOOL3_UNKNOWN;
5983:       }
5984:     }
5985:     if (PetscDefined(USE_COMPLEX) && PetscBool3ToBool(mat->hermitian)) {
5986:       flg = PETSC_FALSE;
5987:       if (l && r) {
5988:         Vec conjugate;

5990:         PetscCall(VecDuplicate(l, &conjugate));
5991:         PetscCall(VecCopy(l, conjugate));
5992:         PetscCall(VecConjugate(conjugate));
5993:         PetscCall(VecEqual(conjugate, r, &flg));
5994:         PetscCall(VecDestroy(&conjugate));
5995:       }
5996:       if (!flg) {
5997:         PetscCall(PetscObjectTypeCompare((PetscObject)mat, MATMPISBAIJ, &flg));
5998:         PetscCheck(!flg, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "For Hermitian MATMPISBAIJ, left and right scaling vectors must be conjugate one of the other");
5999:         mat->hermitian = PETSC_BOOL3_FALSE;
6000:         mat->symmetric = mat->spd = PETSC_BOOL3_UNKNOWN;
6001:       }
6002:     }
6003:   }
6004:   PetscFunctionReturn(PETSC_SUCCESS);
6005: }

6007: /*@
6008:   MatScale - Scales all elements of a matrix by a given number.

6010:   Logically Collective

6012:   Input Parameters:
6013: + mat - the matrix to be scaled
6014: - a   - the scaling value

6016:   Level: intermediate

6018: .seealso: [](ch_matrices), `Mat`, `MatDiagonalScale()`
6019: @*/
6020: PetscErrorCode MatScale(Mat mat, PetscScalar a)
6021: {
6022:   PetscFunctionBegin;
6025:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6026:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6028:   MatCheckPreallocated(mat, 1);

6030:   PetscCall(PetscLogEventBegin(MAT_Scale, mat, 0, 0, 0));
6031:   if (a != (PetscScalar)1.0) {
6032:     PetscUseTypeMethod(mat, scale, a);
6033:     PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6034:   }
6035:   PetscCall(PetscLogEventEnd(MAT_Scale, mat, 0, 0, 0));
6036:   PetscFunctionReturn(PETSC_SUCCESS);
6037: }

6039: /*@
6040:   MatNorm - Calculates various norms of a matrix.

6042:   Collective

6044:   Input Parameters:
6045: + mat  - the matrix
6046: - type - the type of norm, `NORM_1`, `NORM_FROBENIUS`, `NORM_INFINITY`

6048:   Output Parameter:
6049: . nrm - the resulting norm

6051:   Level: intermediate

6053: .seealso: [](ch_matrices), `Mat`, `MatNormApproximate()`
6054: @*/
6055: PetscErrorCode MatNorm(Mat mat, NormType type, PetscReal *nrm)
6056: {
6057:   PetscFunctionBegin;
6061:   PetscAssertPointer(nrm, 3);

6063:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6064:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6065:   MatCheckPreallocated(mat, 1);

6067:   PetscUseTypeMethod(mat, norm, type, nrm);
6068:   PetscFunctionReturn(PETSC_SUCCESS);
6069: }

6071: static PetscErrorCode VecSetFinalNormApp_Private(Vec x)
6072: {
6073:   PetscScalar *ax, nm1;
6074:   PetscInt     st, en, n;

6076:   PetscFunctionBegin;
6077:   PetscCall(VecGetSize(x, &n));
6078:   if (n < 2) PetscFunctionReturn(PETSC_SUCCESS);
6079:   nm1 = n - 1;
6080:   PetscCall(VecGetOwnershipRange(x, &st, &en));
6081:   PetscCall(VecGetArrayWrite(x, &ax));
6082:   for (PetscInt i = st; i < en; i++) {
6083:     const PetscInt    ii = i - st;
6084:     const PetscScalar s  = i % 2 ? -1.0 : 1.0;

6086:     ax[ii] = s * (1.0 + i / nm1);
6087:   }
6088:   PetscCall(VecRestoreArrayWrite(x, &ax));
6089:   PetscFunctionReturn(PETSC_SUCCESS);
6090: }

6092: static PetscErrorCode MatNormApproximateForwardOnly_Private(Mat A, NormType normtype, PetscInt maxit, PetscBool boundtocpu, PetscReal *n)
6093: {
6094:   Vec         x, y;
6095:   PetscReal   normx, normy;
6096:   PetscInt    i, N;
6097:   PetscRandom rnd;

6099:   PetscFunctionBegin;
6100:   if (maxit < 0) maxit = 1;
6101:   PetscCall(PetscRandomCreate(PetscObjectComm((PetscObject)A), &rnd));
6102:   PetscCall(PetscRandomSetFromOptions(rnd));
6103:   PetscCall(MatCreateVecs(A, &x, &y));
6104:   PetscCall(VecBindToCPU(x, boundtocpu));
6105:   PetscCall(VecBindToCPU(y, boundtocpu));
6106:   PetscCall(VecGetSize(x, &N));
6107:   *n = 0.0;
6108:   for (i = 0; i < maxit; i++) {
6109:     PetscCall(VecSetRandom(x, rnd));
6110:     switch (normtype) {
6111:     case NORM_1:
6112:       PetscCall(VecNorm(x, NORM_1, &normx));
6113:       if (normx > 0.0) PetscCall(VecScale(x, 1.0 / normx));
6114:       break;
6115:     case NORM_INFINITY:
6116:       PetscCall(VecShift(x, -0.5));
6117:       PetscCall(VecPointwiseSign(x, x, VEC_SIGN_ZERO_TO_SIGNED_UNIT));
6118:       break;
6119:     case NORM_2:
6120:       PetscCall(VecNormalize(x, NULL));
6121:       break;
6122:     default:
6123:       PetscUnreachable();
6124:     }
6125:     PetscCall(MatMult(A, x, y));
6126:     PetscCall(VecNorm(y, normtype, &normy));
6127:     *n = PetscMax(*n, normy);
6128:     PetscCall(PetscInfo(A, "%s norm forward-only sample %" PetscInt_FMT " -> %g\n", NormTypes[normtype], i, (double)normy));
6129:   }
6130:   PetscCall(VecDestroy(&x));
6131:   PetscCall(VecDestroy(&y));
6132:   PetscCall(PetscRandomDestroy(&rnd));
6133:   PetscFunctionReturn(PETSC_SUCCESS);
6134: }

6136: /*@
6137:   MatNormApproximate - Approximate the norm of a matrix.

6139:   Collective

6141:   Input Parameters:
6142: + A        - the matrix
6143: . normtype - the `NormType`
6144: - maxit    - maximum number of iterations to use

6146:   Output Parameter:
6147: . n - the norm estimate

6149:   Level: intermediate

6151:   Notes:
6152:   Does not need access to the matrix entries; it just performs matrix-vector and transposed matrix-vector products {cite}`Higham1992`, {cite}`doi:10.1137/S0895479899356080`.

6154:   If `maxit` is negative, a default number of iterations (10 for `NORM_1` and `NORM_INFINITY` and 20 for `NORM_2`) is performed.

6156: .seealso: [](ch_matrices), `Mat`, `MatNorm()`
6157: @*/
6158: PetscErrorCode MatNormApproximate(Mat A, NormType normtype, PetscInt maxit, PetscReal *n)
6159: {
6160:   Vec         x, y, w, z;
6161:   PetscReal   normz, adot;
6162:   PetscScalar dot;
6163:   PetscInt    i, j, N, jold = -1;
6164:   PetscBool   boundtocpu = PETSC_TRUE, setherm, isherm, hasop;

6166:   PetscFunctionBegin;
6171:   PetscAssertPointer(n, 4);
6172: #if PetscDefined(HAVE_DEVICE)
6173:   boundtocpu = A->boundtocpu;
6174: #endif
6175:   PetscCall(MatHasOperation(A, MATOP_MULT_HERMITIAN_TRANSPOSE, &hasop));
6176:   switch (normtype) {
6177:   case NORM_INFINITY:
6178:   case NORM_1:
6179:     if (!hasop) {
6180:       PetscCall(MatNormApproximateForwardOnly_Private(A, normtype, maxit, boundtocpu, n));
6181:       i = maxit;
6182:       break;
6183:     } else {
6184:       PetscCall(MatIsHermitianKnown(A, &setherm, &isherm));
6185:       if ((setherm && isherm) || normtype == NORM_1) PetscCall(PetscObjectReference((PetscObject)A));
6186:       else {
6187:         Mat B;

6189:         PetscCall(MatCreateHermitianTranspose(A, &B));
6190:         A = B;
6191:       }
6192:     }
6193:     if (maxit < 0) maxit = 10; /* pure guess */
6194:     PetscCall(MatCreateVecs(A, &x, &y));
6195:     PetscCall(MatCreateVecs(A, &z, &w));
6196:     PetscCall(VecBindToCPU(x, boundtocpu));
6197:     PetscCall(VecBindToCPU(y, boundtocpu));
6198:     PetscCall(VecBindToCPU(z, boundtocpu));
6199:     PetscCall(VecBindToCPU(w, boundtocpu));
6200:     PetscCall(VecGetSize(x, &N));
6201:     PetscCall(VecSet(x, 1. / N));
6202:     *n = 0.0;
6203:     for (i = 0; i < maxit; i++) {
6204:       PetscCall(MatMult(A, x, y));
6205:       PetscCall(VecNorm(y, NORM_1, n));
6206:       if (PetscDefined(USE_COMPLEX)) {
6207:         PetscCall(VecCopy(y, w));
6208:         PetscCall(VecAbs(w));
6209:         PetscCall(VecPointwiseDivide(w, y, w));
6210:       } else PetscCall(VecPointwiseSign(w, y, VEC_SIGN_ZERO_TO_SIGNED_UNIT));
6211:       PetscCall(MatMultHermitianTranspose(A, w, z));
6212:       PetscCall(VecRealPart(z));
6213:       PetscCall(VecNorm(z, NORM_INFINITY, &normz));
6214:       PetscCall(VecDot(x, z, &dot));
6215:       adot = PetscAbsScalar(dot);
6216:       PetscCall(PetscInfo(A, "%s norm it %" PetscInt_FMT " -> %g (%g %g)\n", NormTypes[normtype], i, (double)*n, (double)normz, (double)adot));
6217:       if (normz <= adot && i > 0) {
6218:         PetscCall(PetscInfo(A, "%s norm    converged\n", NormTypes[normtype]));
6219:         break;
6220:       }
6221:       PetscCall(VecAbs(z));
6222:       PetscCall(VecMax(z, &j, &normz));
6223:       if (j == jold) {
6224:         PetscCall(PetscInfo(A, "%s norm it %" PetscInt_FMT " -> breakdown (j==jold)\n", NormTypes[normtype], i));
6225:         break;
6226:       }
6227:       jold = j;
6228:       if (i < maxit - 1) PetscCall(VecSetStdBasis(x, j));
6229:     }
6230:     /* last check */
6231:     if (N > 1) {
6232:       PetscReal ny;

6234:       PetscCall(VecSetFinalNormApp_Private(x));
6235:       PetscCall(MatMult(A, x, y));
6236:       PetscCall(VecNorm(y, NORM_1, &ny));
6237:       ny = 2 * ny / (3 * N);
6238:       PetscCall(PetscInfo(A, "%s norm final check: current %g test %g\n", NormTypes[normtype], (double)*n, (double)ny));
6239:       *n = PetscMax(*n, ny);
6240:     }
6241:     PetscCall(MatDestroy(&A));
6242:     PetscCall(VecDestroy(&x));
6243:     PetscCall(VecDestroy(&w));
6244:     PetscCall(VecDestroy(&y));
6245:     PetscCall(VecDestroy(&z));
6246:     break;
6247:   case NORM_2:
6248:     if (!hasop) {
6249:       PetscCall(MatNormApproximateForwardOnly_Private(A, normtype, maxit, boundtocpu, n));
6250:       i = maxit;
6251:       break;
6252:     }
6253:     if (maxit < 0) maxit = 20; /* pure guess */
6254:     PetscCall(MatCreateVecs(A, &x, &y));
6255:     PetscCall(MatCreateVecs(A, &z, NULL));
6256:     PetscCall(VecBindToCPU(x, boundtocpu));
6257:     PetscCall(VecBindToCPU(y, boundtocpu));
6258:     PetscCall(VecBindToCPU(z, boundtocpu));
6259:     PetscCall(VecSetRandom(x, NULL));
6260:     PetscCall(VecNormalize(x, NULL));
6261:     *n = 0.0;
6262:     for (i = 0; i < maxit; i++) {
6263:       PetscCall(MatMult(A, x, y));
6264:       PetscCall(VecNormalize(y, n));
6265:       PetscCall(MatMultHermitianTranspose(A, y, z));
6266:       PetscCall(VecNorm(z, NORM_2, &normz));
6267:       PetscCall(VecDot(x, z, &dot));
6268:       adot = PetscAbsScalar(dot);
6269:       PetscCall(PetscInfo(A, "%s norm it %" PetscInt_FMT " -> %g (%g %g)\n", NormTypes[normtype], i, (double)*n, (double)normz, (double)adot));
6270:       if (normz <= adot) {
6271:         PetscCall(PetscInfo(A, "%s norm    converged\n", NormTypes[normtype]));
6272:         break;
6273:       }
6274:       if (i < maxit - 1) {
6275:         Vec t;

6277:         PetscCall(VecNormalize(z, NULL));
6278:         t = x;
6279:         x = z;
6280:         z = t;
6281:       }
6282:     }
6283:     PetscCall(VecDestroy(&x));
6284:     PetscCall(VecDestroy(&y));
6285:     PetscCall(VecDestroy(&z));
6286:     break;
6287:   default:
6288:     SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "%s norm not supported", NormTypes[normtype]);
6289:   }
6290:   PetscCall(PetscInfo(A, "%s norm %g computed in %" PetscInt_FMT " iterations\n", NormTypes[normtype], (double)*n, i));
6291:   PetscFunctionReturn(PETSC_SUCCESS);
6292: }

6294: /*
6295:      This variable is used to prevent counting of MatAssemblyBegin() that
6296:    are called from within a MatAssemblyEnd().
6297: */
6298: static PetscInt MatAssemblyEnd_InUse = 0;
6299: /*@
6300:   MatAssemblyBegin - Begins assembling the matrix. This routine should
6301:   be called after completing all calls to `MatSetValues()`.

6303:   Collective

6305:   Input Parameters:
6306: + mat  - the matrix
6307: - type - type of assembly, either `MAT_FLUSH_ASSEMBLY` or `MAT_FINAL_ASSEMBLY`

6309:   Level: beginner

6311:   Notes:
6312:   `MatSetValues()` generally caches the values that belong to other MPI processes. The matrix is ready to
6313:   use only after `MatAssemblyBegin()` and `MatAssemblyEnd()` have been called.

6315:   Use `MAT_FLUSH_ASSEMBLY` when switching between `ADD_VALUES` and `INSERT_VALUES`
6316:   in `MatSetValues()`; use `MAT_FINAL_ASSEMBLY` for the final assembly before
6317:   using the matrix.

6319:   ALL processes that share a matrix MUST call `MatAssemblyBegin()` and `MatAssemblyEnd()` the SAME NUMBER of times, and each time with the
6320:   same flag of `MAT_FLUSH_ASSEMBLY` or `MAT_FINAL_ASSEMBLY` for all processes. Thus you CANNOT locally change from `ADD_VALUES` to `INSERT_VALUES`, that is
6321:   a global collective operation requiring all processes that share the matrix.

6323:   Space for preallocated nonzeros that is not filled by a call to `MatSetValues()` or a related routine are compressed
6324:   out by assembly. If you intend to use that extra space on a subsequent assembly, be sure to insert explicit zeros
6325:   before `MAT_FINAL_ASSEMBLY` so the space is not compressed out.

6327: .seealso: [](ch_matrices), `Mat`, `MatAssemblyEnd()`, `MatSetValues()`, `MatAssembled()`
6328: @*/
6329: PetscErrorCode MatAssemblyBegin(Mat mat, MatAssemblyType type)
6330: {
6331:   PetscFunctionBegin;
6334:   MatCheckPreallocated(mat, 1);
6335:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix. Did you forget to call MatSetUnfactored()?");
6336:   if (mat->assembled) {
6337:     mat->was_assembled = PETSC_TRUE;
6338:     mat->assembled     = PETSC_FALSE;
6339:   }

6341:   if (!MatAssemblyEnd_InUse) {
6342:     PetscCall(PetscLogEventBegin(MAT_AssemblyBegin, mat, 0, 0, 0));
6343:     PetscTryTypeMethod(mat, assemblybegin, type);
6344:     PetscCall(PetscLogEventEnd(MAT_AssemblyBegin, mat, 0, 0, 0));
6345:   } else PetscTryTypeMethod(mat, assemblybegin, type);
6346:   PetscFunctionReturn(PETSC_SUCCESS);
6347: }

6349: /*@
6350:   MatAssembled - Indicates if a matrix has been assembled and is ready for
6351:   use; for example, in matrix-vector product.

6353:   Not Collective

6355:   Input Parameter:
6356: . mat - the matrix

6358:   Output Parameter:
6359: . assembled - `PETSC_TRUE` or `PETSC_FALSE`

6361:   Level: advanced

6363: .seealso: [](ch_matrices), `Mat`, `MatAssemblyEnd()`, `MatSetValues()`, `MatAssemblyBegin()`
6364: @*/
6365: PetscErrorCode MatAssembled(Mat mat, PetscBool *assembled)
6366: {
6367:   PetscFunctionBegin;
6369:   PetscAssertPointer(assembled, 2);
6370:   *assembled = mat->assembled;
6371:   PetscFunctionReturn(PETSC_SUCCESS);
6372: }

6374: /*@
6375:   MatAssemblyEnd - Completes assembling the matrix. This routine should
6376:   be called after `MatAssemblyBegin()`.

6378:   Collective

6380:   Input Parameters:
6381: + mat  - the matrix
6382: - type - type of assembly, either `MAT_FLUSH_ASSEMBLY` or `MAT_FINAL_ASSEMBLY`

6384:   Options Database Key:
6385: . -mat_view viewer_specification - Displays the matrix during this function call. See `PetscOptionsCreateViewer()` for the values of `viewer_specification`

6387:   Level: beginner

6389: .seealso: [](ch_matrices), `Mat`, `MatAssemblyBegin()`, `MatSetValues()`, `PetscDrawOpenX()`, `PetscDrawCreate()`, `MatView()`, `MatAssembled()`, `PetscViewerSocketOpen()`,
6390:           `MatViewFromOptions()`, `PetscObjectViewFromOptions()`, `PetscOptionsCreateViewer()`
6391: @*/
6392: PetscErrorCode MatAssemblyEnd(Mat mat, MatAssemblyType type)
6393: {
6394:   static PetscInt inassm = 0;
6395:   PetscBool       flg    = PETSC_FALSE;

6397:   PetscFunctionBegin;

6401:   inassm++;
6402:   MatAssemblyEnd_InUse++;
6403:   if (MatAssemblyEnd_InUse == 1) { /* Do the logging only the first time through */
6404:     PetscCall(PetscLogEventBegin(MAT_AssemblyEnd, mat, 0, 0, 0));
6405:     PetscTryTypeMethod(mat, assemblyend, type);
6406:     PetscCall(PetscLogEventEnd(MAT_AssemblyEnd, mat, 0, 0, 0));
6407:   } else PetscTryTypeMethod(mat, assemblyend, type);

6409:   /* Flush assembly is not a true assembly */
6410:   if (type != MAT_FLUSH_ASSEMBLY) {
6411:     if (mat->num_ass) {
6412:       if (!mat->symmetry_eternal) {
6413:         mat->symmetric = PETSC_BOOL3_UNKNOWN;
6414:         mat->hermitian = PETSC_BOOL3_UNKNOWN;
6415:       }
6416:       if (!mat->structural_symmetry_eternal && mat->ass_nonzerostate != mat->nonzerostate) mat->structurally_symmetric = PETSC_BOOL3_UNKNOWN;
6417:       if (!mat->spd_eternal) mat->spd = PETSC_BOOL3_UNKNOWN;
6418:     }
6419:     mat->num_ass++;
6420:     mat->assembled        = PETSC_TRUE;
6421:     mat->ass_nonzerostate = mat->nonzerostate;
6422:   }

6424:   mat->insertmode = NOT_SET_VALUES;
6425:   MatAssemblyEnd_InUse--;
6426:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6427:   if (inassm == 1 && type != MAT_FLUSH_ASSEMBLY) {
6428:     PetscCall(MatViewFromOptions(mat, NULL, "-mat_view"));

6430:     if (mat->checksymmetryonassembly) {
6431:       PetscCall(MatIsSymmetric(mat, mat->checksymmetrytol, &flg));
6432:       if (flg) {
6433:         PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "Matrix is symmetric (tolerance %g)\n", (double)mat->checksymmetrytol));
6434:       } else {
6435:         PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "Matrix is not symmetric (tolerance %g)\n", (double)mat->checksymmetrytol));
6436:       }
6437:     }
6438:     if (mat->nullsp && mat->checknullspaceonassembly) PetscCall(MatNullSpaceTest(mat->nullsp, mat, NULL));
6439:   }
6440:   inassm--;
6441:   PetscFunctionReturn(PETSC_SUCCESS);
6442: }

6444: // PetscClangLinter pragma disable: -fdoc-section-header-unknown
6445: /*@
6446:   MatSetOption - Sets a parameter option for a matrix. Some options
6447:   may be specific to certain storage formats. Some options
6448:   determine how values will be inserted (or added). Sorted,
6449:   row-oriented input will generally assemble the fastest. The default
6450:   is row-oriented.

6452:   Logically Collective for certain operations, such as `MAT_SPD`, not collective for `MAT_ROW_ORIENTED`, see `MatOption`

6454:   Input Parameters:
6455: + mat - the matrix
6456: . op  - the option, one of those listed below (and possibly others),
6457: - flg - turn the option on (`PETSC_TRUE`) or off (`PETSC_FALSE`)

6459:   Options Describing Matrix Structure:
6460: + `MAT_SPD`                         - symmetric positive definite
6461: . `MAT_SYMMETRIC`                   - symmetric in terms of both structure and value
6462: . `MAT_HERMITIAN`                   - transpose is the complex conjugation
6463: . `MAT_STRUCTURALLY_SYMMETRIC`      - symmetric nonzero structure
6464: . `MAT_SYMMETRY_ETERNAL`            - indicates the symmetry (or Hermitian structure) or its absence will persist through any changes to the matrix
6465: . `MAT_STRUCTURAL_SYMMETRY_ETERNAL` - indicates the structural symmetry or its absence will persist through any changes to the matrix
6466: . `MAT_SPD_ETERNAL`                 - indicates the value of `MAT_SPD` (true or false) will persist through any changes to the matrix

6468:    These are not really options of the matrix, they are knowledge about the structure of the matrix that users may provide so that they
6469:    do not need to be computed (usually at a high cost)

6471:    Options For Use with `MatSetValues()` and `MatGetValues()`:
6472:    Insert a logically dense subblock, which can be
6473: . `MAT_ROW_ORIENTED`                - row-oriented (default)

6475:    These options reflect the data you pass in with `MatSetValues()` or receive with `MatGetValues()`; it has
6476:    nothing to do with how the data is stored internally in the matrix
6477:    data structure.

6479:    When (re)assembling a matrix, we can restrict the input for
6480:    efficiency/debugging purposes. These options include
6481: . `MAT_NEW_NONZERO_LOCATIONS`       - additional insertions will be allowed if they generate a new nonzero (slow)
6482: . `MAT_FORCE_DIAGONAL_ENTRIES`      - forces diagonal entries to be allocated
6483: . `MAT_IGNORE_OFF_PROC_ENTRIES`     - drops off-process entries
6484: . `MAT_NEW_NONZERO_LOCATION_ERR`    - generates an error for new matrix entry
6485: . `MAT_USE_HASH_TABLE`              - uses a hash table to speed up matrix assembly
6486: . `MAT_NO_OFF_PROC_ENTRIES`         - you know each process will only set values for its own rows, will generate an error if
6487:                                       any process sets values for another process. This avoids all reductions in the MatAssembly routines and thus improves
6488:                                       performance for very large process counts.
6489: - `MAT_SUBSET_OFF_PROC_ENTRIES`     - you know that the first assembly after setting this flag will set a superset
6490:                                       of the off-process entries required for all subsequent assemblies. This avoids a rendezvous step in the MatAssembly
6491:                                       functions, instead sending only neighbor messages.

6493:   Level: intermediate

6495:   Notes:
6496:   Except for `MAT_UNUSED_NONZERO_LOCATION_ERR` and  `MAT_ROW_ORIENTED` all processes that share the matrix must pass the same value in flg!

6498:   Some options are relevant only for particular matrix types and
6499:   are thus ignored by others. Other options are not supported by
6500:   certain matrix types and will generate an error message if set.

6502:   Once `MAT_STRUCTURE_ONLY` has been set to `PETSC_TRUE`, it cannot be set back to `PETSC_FALSE`.

6504:   The matrix properties must be consistent with one another. With real scalars, `MAT_SPD` implies `MAT_SYMMETRIC`, and
6505:   both `MAT_SYMMETRIC` and `MAT_HERMITIAN` imply `MAT_STRUCTURALLY_SYMMETRIC`. Setting a property that contradicts
6506:   another known property generates an error. Still with real scalars, setting either `MAT_SYMMETRIC` or `MAT_HERMITIAN`
6507:   also sets the other to the same value.

6509:   If using Fortran to compute a matrix, one may need to use the column-oriented
6510:   option (or convert to the row-oriented format).

6512:   `MAT_NEW_NONZERO_LOCATIONS` set to `PETSC_FALSE` indicates that any add or insertion
6513:   that would generate a new entry in the nonzero structure is instead
6514:   ignored. Thus, if memory has not already been allocated for this particular
6515:   data, then the insertion is ignored. For dense matrices, in which
6516:   the entire array is allocated, no entries are ever ignored.
6517:   Set after the first `MatAssemblyEnd()`. If this option is set, then the `MatAssemblyBegin()`/`MatAssemblyEnd()` processes has one less global reduction

6519:   `MAT_NEW_NONZERO_LOCATION_ERR` set to `PETSC_TRUE` indicates that any add or insertion
6520:   that would generate a new entry in the nonzero structure instead produces
6521:   an error. (Currently supported for `MATAIJ` and `MATBAIJ` formats only.) If this option is set, then the `MatAssemblyBegin()`/`MatAssemblyEnd()` processes has one less global reduction

6523:   `MAT_NEW_NONZERO_ALLOCATION_ERR` set to `PETSC_TRUE` indicates that any add or insertion
6524:   that would generate a new entry that has not been preallocated will
6525:   instead produce an error. (Currently supported for `MATAIJ` and `MATBAIJ` formats
6526:   only.) This is a useful flag when debugging matrix memory preallocation.
6527:   If this option is set, then the `MatAssemblyBegin()`/`MatAssemblyEnd()` processes has one less global reduction

6529:   `MAT_IGNORE_OFF_PROC_ENTRIES` set to `PETSC_TRUE` indicates entries destined for
6530:   other processes should be dropped, rather than stashed.
6531:   This is useful if you know that the "owning" process is also
6532:   always generating the correct matrix entries, so that PETSc need
6533:   not transfer duplicate entries generated on another process.

6535:   `MAT_USE_HASH_TABLE` indicates that a hash table be used to improve the
6536:   searches during matrix assembly. When this flag is set, the hash table
6537:   is created during the first matrix assembly. This hash table is
6538:   used the next time through, during `MatSetValues()`/`MatSetValuesBlocked()`
6539:   to improve the searching of indices. `MAT_NEW_NONZERO_LOCATIONS` flag
6540:   should be used with `MAT_USE_HASH_TABLE` flag. This option is currently
6541:   supported by `MATMPIBAIJ` format only.

6543:   `MAT_KEEP_NONZERO_PATTERN` indicates when `MatZeroRows()` is called the zeroed entries
6544:   are kept in the nonzero structure. This flag is not used for `MatZeroRowsColumns()`

6546:   `MAT_IGNORE_ZERO_ENTRIES` - for `MATAIJ`, `MATSELL`, and `MATIS` matrices this will stop zero values
6547:   from creating a zero location in the matrix. A zero on the diagonal is exempt and still creates its
6548:   location, so that operations needing a full diagonal, such as `MatSOR()`, keep working. The exemption
6549:   covers the diagonal portion of the owning process's rows; a zero added with `ADD_VALUES` to a row owned
6550:   by another process is dropped as it is stashed and never reaches that test. A matrix assembled without
6551:   preallocation, through `MatSetUp()`, decides the exemption from process-local indices, so it does not
6552:   hold there when the row and column layouts differ

6554:   `MAT_USE_INODES` - indicates using inode version of the code - works with `MATAIJ` matrix types

6556:   `MAT_NO_OFF_PROC_ZERO_ROWS` - you know each process will only zero its own rows. This avoids all reductions in the
6557:   zero row routines and thus improves performance for very large process counts.

6559:   `MAT_IGNORE_LOWER_TRIANGULAR` - For `MATSBAIJ` matrices will ignore any insertions you make in the lower triangular
6560:   part of the matrix (since they should match the upper triangular part).

6562:   `MAT_SORTED_FULL` - each process provides exactly its local rows; all column indices for a given row are passed in a
6563:   single call to `MatSetValues()`, preallocation is perfect, row-oriented, `INSERT_VALUES` is used. Common
6564:   with finite difference schemes with non-periodic boundary conditions.

6566:   Developer Note:
6567:   `MAT_SYMMETRY_ETERNAL`, `MAT_STRUCTURAL_SYMMETRY_ETERNAL`, and `MAT_SPD_ETERNAL` are used by `MatAssemblyEnd()` and in other
6568:   places where otherwise the value of `MAT_SYMMETRIC`, `MAT_STRUCTURALLY_SYMMETRIC` or `MAT_SPD` would need to be changed back
6569:   to `PETSC_BOOL3_UNKNOWN` because the matrix values had changed so the code cannot be certain that the related property had
6570:   not changed.

6572: .seealso: [](ch_matrices), `MatOption`, `Mat`, `MatGetOption()`
6573: @*/
6574: PetscErrorCode MatSetOption(Mat mat, MatOption op, PetscBool flg)
6575: {
6576:   PetscFunctionBegin;
6578:   if (op > 0) {
6581:   }

6583:   PetscCheck(((int)op) > MAT_OPTION_MIN && ((int)op) < MAT_OPTION_MAX, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Options %d is out of range", (int)op);

6585:   switch (op) {
6586:   case MAT_FORCE_DIAGONAL_ENTRIES:
6587:     mat->force_diagonals = flg;
6588:     PetscFunctionReturn(PETSC_SUCCESS);
6589:   case MAT_NO_OFF_PROC_ENTRIES:
6590:     mat->nooffprocentries = flg;
6591:     PetscFunctionReturn(PETSC_SUCCESS);
6592:   case MAT_SUBSET_OFF_PROC_ENTRIES:
6593:     mat->assembly_subset = flg;
6594:     if (!mat->assembly_subset) { /* See the same logic in VecAssembly wrt VEC_SUBSET_OFF_PROC_ENTRIES */
6595: #if !PetscDefined(HAVE_MPIUNI)
6596:       PetscCall(MatStashScatterDestroy_BTS(&mat->stash));
6597: #endif
6598:       mat->stash.first_assembly_done = PETSC_FALSE;
6599:     }
6600:     PetscFunctionReturn(PETSC_SUCCESS);
6601:   case MAT_NO_OFF_PROC_ZERO_ROWS:
6602:     mat->nooffproczerorows = flg;
6603:     PetscFunctionReturn(PETSC_SUCCESS);
6604:   case MAT_SPD:
6605:     PetscCheck(PetscDefined(USE_COMPLEX) || !flg || mat->symmetric != PETSC_BOOL3_FALSE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_SPD to PETSC_TRUE when MAT_SYMMETRIC is PETSC_FALSE");
6606:     PetscCheck(!flg || mat->structurally_symmetric != PETSC_BOOL3_FALSE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_SPD to PETSC_TRUE when MAT_STRUCTURALLY_SYMMETRIC is PETSC_FALSE");
6607:     if (flg) {
6608:       mat->spd                    = PETSC_BOOL3_TRUE;
6609:       mat->symmetric              = PETSC_BOOL3_TRUE;
6610:       mat->structurally_symmetric = PETSC_BOOL3_TRUE;
6611:       if (!PetscDefined(USE_COMPLEX)) mat->hermitian = PETSC_BOOL3_TRUE;
6612:     } else mat->spd = PETSC_BOOL3_FALSE;
6613:     break;
6614:   case MAT_SYMMETRIC:
6615:     PetscCheck(PetscDefined(USE_COMPLEX) || flg || mat->spd != PETSC_BOOL3_TRUE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_SYMMETRIC to PETSC_FALSE when MAT_SPD is PETSC_TRUE");
6616:     PetscCheck(!flg || mat->structurally_symmetric != PETSC_BOOL3_FALSE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_SYMMETRIC to PETSC_TRUE when MAT_STRUCTURALLY_SYMMETRIC is PETSC_FALSE");
6617:     mat->symmetric = PetscBoolToBool3(flg);
6618:     if (flg) mat->structurally_symmetric = PETSC_BOOL3_TRUE;
6619:     if (!PetscDefined(USE_COMPLEX)) mat->hermitian = PetscBoolToBool3(flg);
6620:     break;
6621:   case MAT_HERMITIAN:
6622:     PetscCheck(PetscDefined(USE_COMPLEX) || flg || mat->spd != PETSC_BOOL3_TRUE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_HERMITIAN to PETSC_FALSE when MAT_SPD is PETSC_TRUE");
6623:     PetscCheck(!flg || mat->structurally_symmetric != PETSC_BOOL3_FALSE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_HERMITIAN to PETSC_TRUE when MAT_STRUCTURALLY_SYMMETRIC is PETSC_FALSE");
6624:     mat->hermitian = PetscBoolToBool3(flg);
6625:     if (flg) mat->structurally_symmetric = PETSC_BOOL3_TRUE;
6626:     if (!PetscDefined(USE_COMPLEX)) mat->symmetric = PetscBoolToBool3(flg);
6627:     break;
6628:   case MAT_STRUCTURALLY_SYMMETRIC:
6629:     PetscCheck(flg || mat->spd != PETSC_BOOL3_TRUE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_STRUCTURALLY_SYMMETRIC to PETSC_FALSE when MAT_SPD is PETSC_TRUE");
6630:     PetscCheck(flg || mat->symmetric != PETSC_BOOL3_TRUE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_STRUCTURALLY_SYMMETRIC to PETSC_FALSE when MAT_SYMMETRIC is PETSC_TRUE");
6631:     PetscCheck(flg || mat->hermitian != PETSC_BOOL3_TRUE, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Cannot set MAT_STRUCTURALLY_SYMMETRIC to PETSC_FALSE when MAT_HERMITIAN is PETSC_TRUE");
6632:     mat->structurally_symmetric = PetscBoolToBool3(flg);
6633:     break;
6634:   case MAT_SYMMETRY_ETERNAL:
6635:     PetscCheck(mat->symmetric != PETSC_BOOL3_UNKNOWN, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot set MAT_SYMMETRY_ETERNAL without first setting MAT_SYMMETRIC to PETSC_TRUE or PETSC_FALSE");
6636:     mat->symmetry_eternal = flg;
6637:     if (flg) mat->structural_symmetry_eternal = PETSC_TRUE;
6638:     break;
6639:   case MAT_STRUCTURAL_SYMMETRY_ETERNAL:
6640:     PetscCheck(mat->structurally_symmetric != PETSC_BOOL3_UNKNOWN, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot set MAT_STRUCTURAL_SYMMETRY_ETERNAL without first setting MAT_STRUCTURALLY_SYMMETRIC to PETSC_TRUE or PETSC_FALSE");
6641:     mat->structural_symmetry_eternal = flg;
6642:     break;
6643:   case MAT_SPD_ETERNAL:
6644:     PetscCheck(mat->spd != PETSC_BOOL3_UNKNOWN, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot set MAT_SPD_ETERNAL without first setting MAT_SPD to PETSC_TRUE or PETSC_FALSE");
6645:     mat->spd_eternal = flg;
6646:     if (flg) {
6647:       mat->structural_symmetry_eternal = PETSC_TRUE;
6648:       mat->symmetry_eternal            = PETSC_TRUE;
6649:     }
6650:     break;
6651:   case MAT_STRUCTURE_ONLY:
6652:     PetscCheck(flg || !mat->structure_only, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot set MAT_STRUCTURE_ONLY to PETSC_FALSE after it has been set to PETSC_TRUE");
6653:     mat->structure_only = flg;
6654:     break;
6655:   case MAT_SORTED_FULL:
6656:     mat->sortedfull = flg;
6657:     break;
6658:   default:
6659:     break;
6660:   }
6661:   PetscCheck((op != MAT_ROW_ORIENTED) || ((PetscObject)mat)->type_name, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "The matrix type must be set (MatSetType()) before setting this option");
6662:   PetscTryTypeMethod(mat, setoption, op, flg);
6663:   PetscFunctionReturn(PETSC_SUCCESS);
6664: }

6666: /*@
6667:   MatGetOption - Gets a parameter option that has been set for a matrix.

6669:   Logically Collective

6671:   Input Parameters:
6672: + mat - the matrix
6673: - op  - the option, this only responds to certain options, check the code for which ones

6675:   Output Parameter:
6676: . flg - turn the option on (`PETSC_TRUE`) or off (`PETSC_FALSE`)

6678:   Level: intermediate

6680:   Notes:
6681:   Can only be called after `MatSetSizes()` and `MatSetType()` have been set.

6683:   Certain option values may be unknown, for those use the routines `MatIsSymmetric()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, or
6684:   `MatIsSymmetricKnown()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetricKnown()`

6686: .seealso: [](ch_matrices), `Mat`, `MatOption`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`,
6687:     `MatIsSymmetricKnown()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetricKnown()`
6688: @*/
6689: PetscErrorCode MatGetOption(Mat mat, MatOption op, PetscBool *flg)
6690: {
6691:   PetscFunctionBegin;

6695:   PetscCheck(((int)op) > MAT_OPTION_MIN && ((int)op) < MAT_OPTION_MAX, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Options %d is out of range", (int)op);
6696:   PetscCheck(((PetscObject)mat)->type_name, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_TYPENOTSET, "Cannot get options until type and size have been set, see MatSetType() and MatSetSizes()");

6698:   switch (op) {
6699:   case MAT_NO_OFF_PROC_ENTRIES:
6700:     *flg = mat->nooffprocentries;
6701:     break;
6702:   case MAT_NO_OFF_PROC_ZERO_ROWS:
6703:     *flg = mat->nooffproczerorows;
6704:     break;
6705:   case MAT_SYMMETRIC:
6706:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsSymmetric() or MatIsSymmetricKnown()");
6707:     break;
6708:   case MAT_HERMITIAN:
6709:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsHermitian() or MatIsHermitianKnown()");
6710:     break;
6711:   case MAT_STRUCTURALLY_SYMMETRIC:
6712:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsStructurallySymmetric() or MatIsStructurallySymmetricKnown()");
6713:     break;
6714:   case MAT_SPD:
6715:     SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Use MatIsSPDKnown()");
6716:     break;
6717:   case MAT_SYMMETRY_ETERNAL:
6718:     *flg = mat->symmetry_eternal;
6719:     break;
6720:   case MAT_STRUCTURAL_SYMMETRY_ETERNAL:
6721:     *flg = mat->symmetry_eternal;
6722:     break;
6723:   default:
6724:     break;
6725:   }
6726:   PetscFunctionReturn(PETSC_SUCCESS);
6727: }

6729: /*@
6730:   MatZeroEntries - Zeros all entries of a matrix. For sparse matrices
6731:   this routine retains the old nonzero structure.

6733:   Logically Collective

6735:   Input Parameter:
6736: . mat - the matrix

6738:   Level: intermediate

6740:   Note:
6741:   If the matrix was not preallocated then a default, likely poor preallocation will be set in the matrix, so this should be called after the preallocation phase.
6742:   See the Performance chapter of the users manual for information on preallocating matrices.
6743:   For matrices with the `MAT_STRUCTURE_ONLY` option set to true, this routine leaves the structure and object state unchanged because no numerical values are stored.

6745: .seealso: [](ch_matrices), `Mat`, `MatZeroRows()`, `MatZeroRowsColumns()`
6746: @*/
6747: PetscErrorCode MatZeroEntries(Mat mat)
6748: {
6749:   PetscFunctionBegin;
6752:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6753:   PetscCheck(mat->insertmode == NOT_SET_VALUES, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for matrices where you have set values but not yet assembled");
6754:   MatCheckPreallocated(mat, 1);

6756:   if (mat->structure_only == PETSC_FALSE) {
6757:     PetscCall(PetscLogEventBegin(MAT_ZeroEntries, mat, 0, 0, 0));
6758:     PetscUseTypeMethod(mat, zeroentries);
6759:     PetscCall(PetscLogEventEnd(MAT_ZeroEntries, mat, 0, 0, 0));
6760:     PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6761:   }
6762:   PetscFunctionReturn(PETSC_SUCCESS);
6763: }

6765: /*@
6766:   MatZeroRowsColumns - Zeros all entries (except possibly the main diagonal)
6767:   of a set of rows and columns of a matrix.

6769:   Collective

6771:   Input Parameters:
6772: + mat     - the matrix
6773: . numRows - the number of rows/columns to zero
6774: . rows    - the global row indices
6775: . diag    - value put in the diagonal of the eliminated rows
6776: . x       - optional vector of the solution for zeroed rows (other entries in vector are not used), these must be set before this call
6777: - b       - optional vector of the right-hand side, that will be adjusted by provided solution entries

6779:   Level: intermediate

6781:   Notes:
6782:   This routine, along with `MatZeroRows()`, is typically used to eliminate known Dirichlet boundary conditions from a linear system.

6784:   For each zeroed row, the value of the corresponding `b` is set to diag times the value of the corresponding `x`.
6785:   The other entries of `b` will be adjusted by the known values of `x` times the corresponding matrix entries in the columns that are being eliminated

6787:   If the resulting linear system is to be solved with `KSP` then one can (but does not have to) call `KSPSetInitialGuessNonzero()` to allow the
6788:   Krylov method to take advantage of the known solution on the zeroed rows.

6790:   For the parallel case, all processes that share the matrix (i.e.,
6791:   those in the communicator used for matrix creation) MUST call this
6792:   routine, regardless of whether any rows being zeroed are owned by
6793:   them.

6795:   Unlike `MatZeroRows()`, this ignores the `MAT_KEEP_NONZERO_PATTERN` option value set with `MatSetOption()`, it merely zeros those entries in the matrix, but never
6796:   removes them from the nonzero pattern. The nonzero pattern of the matrix can still change if a nonzero needs to be inserted on a diagonal entry that was previously
6797:   missing.

6799:   Each process can indicate any rows in the entire matrix to be zeroed (i.e. each process does NOT have to
6800:   list only rows local to itself).

6802:   The option `MAT_NO_OFF_PROC_ZERO_ROWS` does not apply to this routine.

6804: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRows()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6805:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
6806: @*/
6807: PetscErrorCode MatZeroRowsColumns(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
6808: {
6809:   PetscFunctionBegin;
6812:   if (numRows) PetscAssertPointer(rows, 3);
6813:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6814:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6815:   MatCheckPreallocated(mat, 1);

6817:   PetscUseTypeMethod(mat, zerorowscolumns, numRows, rows, diag, x, b);
6818:   PetscCall(MatViewFromOptions(mat, NULL, "-mat_view"));
6819:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6820:   PetscFunctionReturn(PETSC_SUCCESS);
6821: }

6823: /*@
6824:   MatZeroRowsColumnsIS - Zeros all entries (except possibly the main diagonal)
6825:   of a set of rows and columns of a matrix.

6827:   Collective

6829:   Input Parameters:
6830: + mat  - the matrix
6831: . is   - the rows to zero
6832: . diag - value put in all diagonals of eliminated rows (0.0 will even eliminate diagonal entry)
6833: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
6834: - b    - optional vector of right-hand side, that will be adjusted by provided solution

6836:   Level: intermediate

6838:   Note:
6839:   See `MatZeroRowsColumns()` for details on how this routine operates.

6841: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6842:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRows()`, `MatZeroRowsColumnsStencil()`
6843: @*/
6844: PetscErrorCode MatZeroRowsColumnsIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
6845: {
6846:   PetscInt        numRows;
6847:   const PetscInt *rows;

6849:   PetscFunctionBegin;
6854:   PetscCall(ISGetLocalSize(is, &numRows));
6855:   PetscCall(ISGetIndices(is, &rows));
6856:   PetscCall(MatZeroRowsColumns(mat, numRows, rows, diag, x, b));
6857:   PetscCall(ISRestoreIndices(is, &rows));
6858:   PetscFunctionReturn(PETSC_SUCCESS);
6859: }

6861: /*@
6862:   MatZeroRows - Zeros all entries (except possibly the main diagonal)
6863:   of a set of rows of a matrix.

6865:   Collective

6867:   Input Parameters:
6868: + mat     - the matrix
6869: . numRows - the number of rows to zero
6870: . rows    - the global row indices
6871: . diag    - value put in the diagonal of the zeroed rows
6872: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used), these must be set before this call
6873: - b       - optional vector of right-hand side, that will be adjusted by provided solution entries

6875:   Level: intermediate

6877:   Notes:
6878:   This routine, along with `MatZeroRowsColumns()`, is typically used to eliminate known Dirichlet boundary conditions from a linear system.

6880:   For each zeroed row, the value of the corresponding `b` is set to `diag` times the value of the corresponding `x`.

6882:   If the resulting linear system is to be solved with `KSP` then one can (but does not have to) call `KSPSetInitialGuessNonzero()` to allow the
6883:   Krylov method to take advantage of the known solution on the zeroed rows.

6885:   May be followed by using a `PC` of type `PCREDISTRIBUTE` to solve the reduced problem (`PCDISTRIBUTE` completely eliminates the zeroed rows and their corresponding columns)
6886:   from the matrix.

6888:   Unlike `MatZeroRowsColumns()` for the `MATAIJ` and `MATBAIJ` matrix formats this removes the old nonzero structure, from the eliminated rows of the matrix
6889:   but does not release memory. Because of this removal matrix-vector products with the adjusted matrix will be a bit faster. For the dense
6890:   formats this does not alter the nonzero structure.

6892:   If the option `MatSetOption`(mat,`MAT_KEEP_NONZERO_PATTERN`,`PETSC_TRUE`) the nonzero structure
6893:   of the matrix is not changed the values are
6894:   merely zeroed.

6896:   The user can set a value in the diagonal entry (or for the `MATAIJ` format
6897:   formats can optionally remove the main diagonal entry from the
6898:   nonzero structure as well, by passing 0.0 as the final argument).

6900:   For the parallel case, all processes that share the matrix (i.e.,
6901:   those in the communicator used for matrix creation) MUST call this
6902:   routine, regardless of whether any rows being zeroed are owned by
6903:   them.

6905:   Each process can indicate any rows in the entire matrix to be zeroed (i.e. each process does NOT have to
6906:   list only rows local to itself).

6908:   You can call `MatSetOption`(mat,`MAT_NO_OFF_PROC_ZERO_ROWS`,`PETSC_TRUE`) if each process indicates only rows it
6909:   owns that are to be zeroed. This saves a global synchronization in the implementation.

6911: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6912:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`, `PCREDISTRIBUTE`, `MAT_KEEP_NONZERO_PATTERN`
6913: @*/
6914: PetscErrorCode MatZeroRows(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
6915: {
6916:   PetscFunctionBegin;
6919:   if (numRows) PetscAssertPointer(rows, 3);
6920:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
6921:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
6922:   MatCheckPreallocated(mat, 1);

6924:   PetscUseTypeMethod(mat, zerorows, numRows, rows, diag, x, b);
6925:   PetscCall(MatViewFromOptions(mat, NULL, "-mat_view"));
6926:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
6927:   PetscFunctionReturn(PETSC_SUCCESS);
6928: }

6930: /*@
6931:   MatZeroRowsIS - Zeros all entries (except possibly the main diagonal)
6932:   of a set of rows of a matrix indicated by an `IS`

6934:   Collective

6936:   Input Parameters:
6937: + mat  - the matrix
6938: . is   - index set, `IS`, of rows to remove (if `NULL` then no row is removed)
6939: . diag - value put in all diagonals of eliminated rows
6940: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
6941: - b    - optional vector of right-hand side, that will be adjusted by provided solution

6943:   Level: intermediate

6945:   Note:
6946:   See `MatZeroRows()` for details on how this routine operates.

6948: .seealso: [](ch_matrices), `Mat`, `MatZeroRows()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
6949:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`, `IS`
6950: @*/
6951: PetscErrorCode MatZeroRowsIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
6952: {
6953:   PetscInt        numRows = 0;
6954:   const PetscInt *rows    = NULL;

6956:   PetscFunctionBegin;
6959:   if (is) {
6961:     PetscCall(ISGetLocalSize(is, &numRows));
6962:     PetscCall(ISGetIndices(is, &rows));
6963:   }
6964:   PetscCall(MatZeroRows(mat, numRows, rows, diag, x, b));
6965:   if (is) PetscCall(ISRestoreIndices(is, &rows));
6966:   PetscFunctionReturn(PETSC_SUCCESS);
6967: }

6969: /*@
6970:   MatZeroRowsStencil - Zeros all entries (except possibly the main diagonal)
6971:   of a set of rows of a matrix indicated by a `MatStencil`. These rows must be local to the process.

6973:   Collective

6975:   Input Parameters:
6976: + mat     - the matrix
6977: . numRows - the number of rows to remove
6978: . rows    - the grid coordinates (and component number when dof > 1) for matrix rows indicated by an array of `MatStencil`
6979: . diag    - value put in all diagonals of eliminated rows (0.0 will even eliminate diagonal entry)
6980: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
6981: - b       - optional vector of right-hand side, that will be adjusted by provided solution

6983:   Level: intermediate

6985:   Notes:
6986:   See `MatZeroRows()` for details on how this routine operates.

6988:   The grid coordinates are across the entire grid, not just the local portion

6990:   For periodic boundary conditions use negative indices for values to the left (below 0; that are to be
6991:   obtained by wrapping values from right edge). For values to the right of the last entry using that index plus one
6992:   etc to obtain values that obtained by wrapping the values from the left edge. This does not work for anything but the
6993:   `DM_BOUNDARY_PERIODIC` boundary type.

6995:   For indices that don't mean anything for your case (like the `k` index when working in 2d) or the `c` index when you have
6996:   a single value per point) you can skip filling those indices.

6998:   Fortran Note:
6999:   `idxm` and `idxn` should be declared as
7000: .vb
7001:     MatStencil idxm(4, m)
7002: .ve
7003:   and the values inserted using
7004: .vb
7005:     idxm(MatStencil_i, 1) = i
7006:     idxm(MatStencil_j, 1) = j
7007:     idxm(MatStencil_k, 1) = k
7008:     idxm(MatStencil_c, 1) = c
7009:    etc
7010: .ve

7012: .seealso: [](ch_matrices), `Mat`, `MatStencil`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRows()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
7013:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
7014: @*/
7015: PetscErrorCode MatZeroRowsStencil(Mat mat, PetscInt numRows, const MatStencil rows[], PetscScalar diag, Vec x, Vec b)
7016: {
7017:   PetscInt  dim    = mat->stencil.dim;
7018:   PetscInt  sdim   = dim - (1 - (PetscInt)mat->stencil.noc);
7019:   PetscInt *dims   = mat->stencil.dims + 1;
7020:   PetscInt *starts = mat->stencil.starts;
7021:   PetscInt *dxm    = (PetscInt *)rows;
7022:   PetscInt *jdxm, i, j, tmp, numNewRows = 0;

7024:   PetscFunctionBegin;
7027:   if (numRows) PetscAssertPointer(rows, 3);

7029:   PetscCall(PetscMalloc1(numRows, &jdxm));
7030:   for (i = 0; i < numRows; ++i) {
7031:     /* Skip unused dimensions (they are ordered k, j, i, c) */
7032:     for (j = 0; j < 3 - sdim; ++j) dxm++;
7033:     /* Local index in X dir */
7034:     tmp = *dxm++ - starts[0];
7035:     /* Loop over remaining dimensions */
7036:     for (j = 0; j < dim - 1; ++j) {
7037:       /* If nonlocal, set index to be negative */
7038:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = PETSC_INT_MIN;
7039:       /* Update local index */
7040:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
7041:     }
7042:     /* Skip component slot if necessary */
7043:     if (mat->stencil.noc) dxm++;
7044:     /* Local row number */
7045:     if (tmp >= 0) jdxm[numNewRows++] = tmp;
7046:   }
7047:   PetscCall(MatZeroRowsLocal(mat, numNewRows, jdxm, diag, x, b));
7048:   PetscCall(PetscFree(jdxm));
7049:   PetscFunctionReturn(PETSC_SUCCESS);
7050: }

7052: /*@
7053:   MatZeroRowsColumnsStencil - Zeros all row and column entries (except possibly the main diagonal)
7054:   of a set of rows and columns of a matrix.

7056:   Collective

7058:   Input Parameters:
7059: + mat     - the matrix
7060: . numRows - the number of rows/columns to remove
7061: . rows    - the grid coordinates (and component number when dof > 1) for matrix rows
7062: . diag    - value put in all diagonals of eliminated rows (0.0 will even eliminate diagonal entry)
7063: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
7064: - b       - optional vector of right-hand side, that will be adjusted by provided solution

7066:   Level: intermediate

7068:   Notes:
7069:   See `MatZeroRowsColumns()` for details on how this routine operates.

7071:   The grid coordinates are across the entire grid, not just the local portion

7073:   For periodic boundary conditions use negative indices for values to the left (below 0; that are to be
7074:   obtained by wrapping values from right edge). For values to the right of the last entry using that index plus one
7075:   etc to obtain values that obtained by wrapping the values from the left edge. This does not work for anything but the
7076:   `DM_BOUNDARY_PERIODIC` boundary type.

7078:   For indices that don't mean anything for your case (like the `k` index when working in 2d) or the `c` index when you have
7079:   a single value per point) you can skip filling those indices.

7081:   Fortran Note:
7082:   `idxm` and `idxn` should be declared as
7083: .vb
7084:     MatStencil idxm(4, m)
7085: .ve
7086:   and the values inserted using
7087: .vb
7088:     idxm(MatStencil_i, 1) = i
7089:     idxm(MatStencil_j, 1) = j
7090:     idxm(MatStencil_k, 1) = k
7091:     idxm(MatStencil_c, 1) = c
7092:     etc
7093: .ve

7095: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
7096:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRows()`
7097: @*/
7098: PetscErrorCode MatZeroRowsColumnsStencil(Mat mat, PetscInt numRows, const MatStencil rows[], PetscScalar diag, Vec x, Vec b)
7099: {
7100:   PetscInt  dim    = mat->stencil.dim;
7101:   PetscInt  sdim   = dim - (1 - (PetscInt)mat->stencil.noc);
7102:   PetscInt *dims   = mat->stencil.dims + 1;
7103:   PetscInt *starts = mat->stencil.starts;
7104:   PetscInt *dxm    = (PetscInt *)rows;
7105:   PetscInt *jdxm, i, j, tmp, numNewRows = 0;

7107:   PetscFunctionBegin;
7110:   if (numRows) PetscAssertPointer(rows, 3);

7112:   PetscCall(PetscMalloc1(numRows, &jdxm));
7113:   for (i = 0; i < numRows; ++i) {
7114:     /* Skip unused dimensions (they are ordered k, j, i, c) */
7115:     for (j = 0; j < 3 - sdim; ++j) dxm++;
7116:     /* Local index in X dir */
7117:     tmp = *dxm++ - starts[0];
7118:     /* Loop over remaining dimensions */
7119:     for (j = 0; j < dim - 1; ++j) {
7120:       /* If nonlocal, set index to be negative */
7121:       if ((*dxm++ - starts[j + 1]) < 0 || tmp < 0) tmp = PETSC_INT_MIN;
7122:       /* Update local index */
7123:       else tmp = tmp * dims[j] + *(dxm - 1) - starts[j + 1];
7124:     }
7125:     /* Skip component slot if necessary */
7126:     if (mat->stencil.noc) dxm++;
7127:     /* Local row number */
7128:     if (tmp >= 0) jdxm[numNewRows++] = tmp;
7129:   }
7130:   PetscCall(MatZeroRowsColumnsLocal(mat, numNewRows, jdxm, diag, x, b));
7131:   PetscCall(PetscFree(jdxm));
7132:   PetscFunctionReturn(PETSC_SUCCESS);
7133: }

7135: /*@
7136:   MatZeroRowsLocal - Zeros all entries (except possibly the main diagonal)
7137:   of a set of rows of a matrix; using local numbering of rows.

7139:   Collective

7141:   Input Parameters:
7142: + mat     - the matrix
7143: . numRows - the number of rows to remove
7144: . rows    - the local row indices
7145: . diag    - value put in all diagonals of eliminated rows
7146: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
7147: - b       - optional vector of right-hand side, that will be adjusted by provided solution

7149:   Level: intermediate

7151:   Notes:
7152:   Before calling `MatZeroRowsLocal()`, the user must first set the
7153:   local-to-global mapping by calling MatSetLocalToGlobalMapping(), this is often already set for matrices obtained with `DMCreateMatrix()`.

7155:   See `MatZeroRows()` for details on how this routine operates.

7157: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRows()`, `MatSetOption()`,
7158:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
7159: @*/
7160: PetscErrorCode MatZeroRowsLocal(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
7161: {
7162:   PetscFunctionBegin;
7165:   if (numRows) PetscAssertPointer(rows, 3);
7166:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7167:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7168:   MatCheckPreallocated(mat, 1);

7170:   if (mat->ops->zerorowslocal) {
7171:     PetscUseTypeMethod(mat, zerorowslocal, numRows, rows, diag, x, b);
7172:   } else {
7173:     IS        is, newis;
7174:     PetscInt *newRows, nl = 0;

7176:     PetscCheck(mat->rmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Need to provide local to global mapping to matrix first");
7177:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, numRows, rows, PETSC_USE_POINTER, &is));
7178:     PetscCall(ISLocalToGlobalMappingApplyIS(mat->rmap->mapping, is, &newis));
7179:     PetscCall(ISGetIndices(newis, (const PetscInt **)&newRows));
7180:     for (PetscInt i = 0; i < numRows; i++)
7181:       if (newRows[i] > -1) newRows[nl++] = newRows[i];
7182:     PetscUseTypeMethod(mat, zerorows, nl, newRows, diag, x, b);
7183:     PetscCall(ISRestoreIndices(newis, (const PetscInt **)&newRows));
7184:     PetscCall(ISDestroy(&newis));
7185:     PetscCall(ISDestroy(&is));
7186:   }
7187:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
7188:   PetscFunctionReturn(PETSC_SUCCESS);
7189: }

7191: /*@
7192:   MatZeroRowsLocalIS - Zeros all entries (except possibly the main diagonal)
7193:   of a set of rows of a matrix; using local numbering of rows.

7195:   Collective

7197:   Input Parameters:
7198: + mat  - the matrix
7199: . is   - index set of rows to remove
7200: . diag - value put in all diagonals of eliminated rows
7201: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
7202: - b    - optional vector of right-hand side, that will be adjusted by provided solution

7204:   Level: intermediate

7206:   Notes:
7207:   Before calling `MatZeroRowsLocalIS()`, the user must first set the
7208:   local-to-global mapping by calling `MatSetLocalToGlobalMapping()`, this is often already set for matrices obtained with `DMCreateMatrix()`.

7210:   See `MatZeroRows()` for details on how this routine operates.

7212: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRows()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
7213:           `MatZeroRowsColumnsLocal()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
7214: @*/
7215: PetscErrorCode MatZeroRowsLocalIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
7216: {
7217:   PetscInt        numRows;
7218:   const PetscInt *rows;

7220:   PetscFunctionBegin;
7224:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7225:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7226:   MatCheckPreallocated(mat, 1);

7228:   PetscCall(ISGetLocalSize(is, &numRows));
7229:   PetscCall(ISGetIndices(is, &rows));
7230:   PetscCall(MatZeroRowsLocal(mat, numRows, rows, diag, x, b));
7231:   PetscCall(ISRestoreIndices(is, &rows));
7232:   PetscFunctionReturn(PETSC_SUCCESS);
7233: }

7235: /*@
7236:   MatZeroRowsColumnsLocal - Zeros all entries (except possibly the main diagonal)
7237:   of a set of rows and columns of a matrix; using local numbering of rows.

7239:   Collective

7241:   Input Parameters:
7242: + mat     - the matrix
7243: . numRows - the number of rows to remove
7244: . rows    - the global row indices
7245: . diag    - value put in all diagonals of eliminated rows
7246: . x       - optional vector of solutions for zeroed rows (other entries in vector are not used)
7247: - b       - optional vector of right-hand side, that will be adjusted by provided solution

7249:   Level: intermediate

7251:   Notes:
7252:   Before calling `MatZeroRowsColumnsLocal()`, the user must first set the
7253:   local-to-global mapping by calling `MatSetLocalToGlobalMapping()`, this is often already set for matrices obtained with `DMCreateMatrix()`.

7255:   See `MatZeroRowsColumns()` for details on how this routine operates.

7257: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
7258:           `MatZeroRows()`, `MatZeroRowsColumnsLocalIS()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
7259: @*/
7260: PetscErrorCode MatZeroRowsColumnsLocal(Mat mat, PetscInt numRows, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
7261: {
7262:   PetscFunctionBegin;
7265:   if (numRows) PetscAssertPointer(rows, 3);
7266:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7267:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7268:   MatCheckPreallocated(mat, 1);

7270:   if (mat->ops->zerorowscolumnslocal) {
7271:     PetscUseTypeMethod(mat, zerorowscolumnslocal, numRows, rows, diag, x, b);
7272:   } else {
7273:     IS        is, newis;
7274:     PetscInt *newRows, nl = 0;

7276:     PetscCheck(mat->rmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Need to provide local to global mapping to matrix first");
7277:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, numRows, rows, PETSC_USE_POINTER, &is));
7278:     PetscCall(ISLocalToGlobalMappingApplyIS(mat->rmap->mapping, is, &newis));
7279:     PetscCall(ISGetIndices(newis, (const PetscInt **)&newRows));
7280:     for (PetscInt i = 0; i < numRows; i++)
7281:       if (newRows[i] > -1) newRows[nl++] = newRows[i];
7282:     PetscUseTypeMethod(mat, zerorowscolumns, nl, newRows, diag, x, b);
7283:     PetscCall(ISRestoreIndices(newis, (const PetscInt **)&newRows));
7284:     PetscCall(ISDestroy(&newis));
7285:     PetscCall(ISDestroy(&is));
7286:   }
7287:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
7288:   PetscFunctionReturn(PETSC_SUCCESS);
7289: }

7291: /*@
7292:   MatZeroRowsColumnsLocalIS - Zeros all entries (except possibly the main diagonal)
7293:   of a set of rows and columns of a matrix; using local numbering of rows.

7295:   Collective

7297:   Input Parameters:
7298: + mat  - the matrix
7299: . is   - index set of rows to remove
7300: . diag - value put in all diagonals of eliminated rows
7301: . x    - optional vector of solutions for zeroed rows (other entries in vector are not used)
7302: - b    - optional vector of right-hand side, that will be adjusted by provided solution

7304:   Level: intermediate

7306:   Notes:
7307:   Before calling `MatZeroRowsColumnsLocalIS()`, the user must first set the
7308:   local-to-global mapping by calling `MatSetLocalToGlobalMapping()`, this is often already set for matrices obtained with `DMCreateMatrix()`.

7310:   See `MatZeroRowsColumns()` for details on how this routine operates.

7312: .seealso: [](ch_matrices), `Mat`, `MatZeroRowsIS()`, `MatZeroRowsColumns()`, `MatZeroRowsLocalIS()`, `MatZeroRowsStencil()`, `MatZeroEntries()`, `MatZeroRowsLocal()`, `MatSetOption()`,
7313:           `MatZeroRowsColumnsLocal()`, `MatZeroRows()`, `MatZeroRowsColumnsIS()`, `MatZeroRowsColumnsStencil()`
7314: @*/
7315: PetscErrorCode MatZeroRowsColumnsLocalIS(Mat mat, IS is, PetscScalar diag, Vec x, Vec b)
7316: {
7317:   PetscInt        numRows;
7318:   const PetscInt *rows;

7320:   PetscFunctionBegin;
7324:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7325:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7326:   MatCheckPreallocated(mat, 1);

7328:   PetscCall(ISGetLocalSize(is, &numRows));
7329:   PetscCall(ISGetIndices(is, &rows));
7330:   PetscCall(MatZeroRowsColumnsLocal(mat, numRows, rows, diag, x, b));
7331:   PetscCall(ISRestoreIndices(is, &rows));
7332:   PetscFunctionReturn(PETSC_SUCCESS);
7333: }

7335: /*@
7336:   MatGetSize - Returns the numbers of rows and columns in a matrix.

7338:   Not Collective

7340:   Input Parameter:
7341: . mat - the matrix

7343:   Output Parameters:
7344: + m - the number of global rows
7345: - n - the number of global columns

7347:   Level: beginner

7349:   Note:
7350:   Both output parameters can be `NULL` on input.

7352: .seealso: [](ch_matrices), `Mat`, `MatSetSizes()`, `MatGetLocalSize()`
7353: @*/
7354: PetscErrorCode MatGetSize(Mat mat, PetscInt *m, PetscInt *n)
7355: {
7356:   PetscFunctionBegin;
7358:   if (m) *m = mat->rmap->N;
7359:   if (n) *n = mat->cmap->N;
7360:   PetscFunctionReturn(PETSC_SUCCESS);
7361: }

7363: /*@
7364:   MatGetLocalSize - For most matrix formats, excluding `MATELEMENTAL` and `MATSCALAPACK`, Returns the number of local rows and local columns
7365:   of a matrix. For all matrices this is the local size of the left and right vectors as returned by `MatCreateVecs()`.

7367:   Not Collective

7369:   Input Parameter:
7370: . mat - the matrix

7372:   Output Parameters:
7373: + m - the number of local rows, use `NULL` to not obtain this value
7374: - n - the number of local columns, use `NULL` to not obtain this value

7376:   Level: beginner

7378: .seealso: [](ch_matrices), `Mat`, `MatSetSizes()`, `MatGetSize()`
7379: @*/
7380: PetscErrorCode MatGetLocalSize(Mat mat, PetscInt *m, PetscInt *n)
7381: {
7382:   PetscFunctionBegin;
7384:   if (m) PetscAssertPointer(m, 2);
7385:   if (n) PetscAssertPointer(n, 3);
7386:   if (m) *m = mat->rmap->n;
7387:   if (n) *n = mat->cmap->n;
7388:   PetscFunctionReturn(PETSC_SUCCESS);
7389: }

7391: /*@
7392:   MatGetOwnershipRangeColumn - Returns the range of matrix columns associated with rows of a
7393:   vector one multiplies this matrix by that are owned by this process.

7395:   Not Collective, unless matrix has not been allocated, then collective

7397:   Input Parameter:
7398: . mat - the matrix

7400:   Output Parameters:
7401: + m - the global index of the first local column, use `NULL` to not obtain this value
7402: - n - one more than the global index of the last local column, use `NULL` to not obtain this value

7404:   Level: developer

7406:   Notes:
7407:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

7409:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
7410:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

7412:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
7413:   the local values in the matrix.

7415:   Returns the columns of the "diagonal block" for most sparse matrix formats. See [Matrix
7416:   Layouts](sec_matlayout) for details on matrix layouts.

7418: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRange()`, `MatGetOwnershipRanges()`, `MatGetOwnershipRangesColumn()`, `PetscLayout`,
7419:           `MatSetSizes()`, `MatCreateAIJ()`, `DMDAGetGhostCorners()`, `DM`
7420: @*/
7421: PetscErrorCode MatGetOwnershipRangeColumn(Mat mat, PetscInt *m, PetscInt *n)
7422: {
7423:   PetscFunctionBegin;
7426:   if (m) PetscAssertPointer(m, 2);
7427:   if (n) PetscAssertPointer(n, 3);
7428:   MatCheckPreallocated(mat, 1);
7429:   if (m) *m = mat->cmap->rstart;
7430:   if (n) *n = mat->cmap->rend;
7431:   PetscFunctionReturn(PETSC_SUCCESS);
7432: }

7434: /*@
7435:   MatGetOwnershipRange - For matrices that own values by row, excludes `MATELEMENTAL` and `MATSCALAPACK`, returns the range of matrix rows owned by
7436:   this MPI process.

7438:   Not Collective

7440:   Input Parameter:
7441: . mat - the matrix

7443:   Output Parameters:
7444: + m - the global index of the first local row, use `NULL` to not obtain this value
7445: - n - one more than the global index of the last local row, use `NULL` to not obtain this value

7447:   Level: beginner

7449:   Notes:
7450:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

7452:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
7453:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

7455:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
7456:   the local values in the matrix.

7458:   The high argument is one more than the last element stored locally.

7460:   For all matrices  it returns the range of matrix rows associated with rows of a vector that
7461:   would contain the result of a matrix vector product with this matrix. See [Matrix
7462:   Layouts](sec_matlayout) for details on matrix layouts.

7464: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRanges()`, `MatGetOwnershipRangeColumn()`, `MatGetOwnershipRangesColumn()`, `PetscSplitOwnership()`,
7465:           `PetscSplitOwnershipBlock()`, `PetscLayout`, `MatSetSizes()`, `MatCreateAIJ()`, `DMDAGetGhostCorners()`, `DM`
7466: @*/
7467: PetscErrorCode MatGetOwnershipRange(Mat mat, PetscInt *m, PetscInt *n)
7468: {
7469:   PetscFunctionBegin;
7472:   if (m) PetscAssertPointer(m, 2);
7473:   if (n) PetscAssertPointer(n, 3);
7474:   MatCheckPreallocated(mat, 1);
7475:   if (m) *m = mat->rmap->rstart;
7476:   if (n) *n = mat->rmap->rend;
7477:   PetscFunctionReturn(PETSC_SUCCESS);
7478: }

7480: /*@
7481:   MatGetOwnershipRanges - For matrices that own values by row, excludes `MATELEMENTAL` and
7482:   `MATSCALAPACK`, returns the range of matrix rows owned by each process.

7484:   Not Collective, unless matrix has not been allocated

7486:   Input Parameter:
7487: . mat - the matrix

7489:   Output Parameter:
7490: . ranges - start of each process's portion plus one more than the total length at the end, of length `size` + 1
7491:            where `size` is the number of MPI processes used by `mat`

7493:   Level: beginner

7495:   Notes:
7496:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

7498:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
7499:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

7501:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
7502:   the local values in the matrix.

7504:   For all matrices  it returns the ranges of matrix rows associated with rows of a vector that
7505:   would contain the result of a matrix vector product with this matrix. See [Matrix
7506:   Layouts](sec_matlayout) for details on matrix layouts.

7508: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRange()`, `MatGetOwnershipRangeColumn()`, `MatGetOwnershipRangesColumn()`, `PetscLayout`,
7509:           `PetscSplitOwnership()`, `PetscSplitOwnershipBlock()`, `MatSetSizes()`, `MatCreateAIJ()`,
7510:           `DMDAGetGhostCorners()`, `DM`
7511: @*/
7512: PetscErrorCode MatGetOwnershipRanges(Mat mat, const PetscInt *ranges[])
7513: {
7514:   PetscFunctionBegin;
7517:   MatCheckPreallocated(mat, 1);
7518:   PetscCall(PetscLayoutGetRanges(mat->rmap, ranges));
7519:   PetscFunctionReturn(PETSC_SUCCESS);
7520: }

7522: /*@
7523:   MatGetOwnershipRangesColumn - Returns the ranges of matrix columns associated with rows of a
7524:   vector one multiplies this vector by that are owned by each process.

7526:   Not Collective, unless matrix has not been allocated

7528:   Input Parameter:
7529: . mat - the matrix

7531:   Output Parameter:
7532: . ranges - start of each process's portion plus one more than the total length at the end

7534:   Level: beginner

7536:   Notes:
7537:   If the `Mat` was obtained from a `DM` with `DMCreateMatrix()`, then the range values are determined by the specific `DM`.

7539:   If the `Mat` was created directly the range values are determined by the local size passed to `MatSetSizes()` or `MatCreateAIJ()`.
7540:   If `PETSC_DECIDE` was passed as the local size, then the vector uses default values for the range using `PetscSplitOwnership()`.

7542:   For certain `DM`, such as `DMDA`, it is better to use `DM` specific routines, such as `DMDAGetGhostCorners()`, to determine
7543:   the local values in the matrix.

7545:   Returns the columns of the "diagonal blocks", for most sparse matrix formats. See [Matrix
7546:   Layouts](sec_matlayout) for details on matrix layouts.

7548: .seealso: [](ch_matrices), `Mat`, `MatGetOwnershipRange()`, `MatGetOwnershipRangeColumn()`, `MatGetOwnershipRanges()`,
7549:           `PetscSplitOwnership()`, `PetscSplitOwnershipBlock()`, `PetscLayout`, `MatSetSizes()`, `MatCreateAIJ()`,
7550:           `DMDAGetGhostCorners()`, `DM`
7551: @*/
7552: PetscErrorCode MatGetOwnershipRangesColumn(Mat mat, const PetscInt *ranges[])
7553: {
7554:   PetscFunctionBegin;
7557:   MatCheckPreallocated(mat, 1);
7558:   PetscCall(PetscLayoutGetRanges(mat->cmap, ranges));
7559:   PetscFunctionReturn(PETSC_SUCCESS);
7560: }

7562: /*@
7563:   MatGetOwnershipIS - Get row and column ownership of a matrices' values as index sets.

7565:   Not Collective

7567:   Input Parameter:
7568: . A - matrix

7570:   Output Parameters:
7571: + rows - rows in which this process owns elements, , use `NULL` to not obtain this value
7572: - cols - columns in which this process owns elements, use `NULL` to not obtain this value

7574:   Level: intermediate

7576:   Note:
7577:   You should call `ISDestroy()` on the returned `IS`

7579:   For most matrices, excluding `MATELEMENTAL` and `MATSCALAPACK`, this corresponds to values
7580:   returned by `MatGetOwnershipRange()`, `MatGetOwnershipRangeColumn()`. For `MATELEMENTAL` and
7581:   `MATSCALAPACK` the ownership is more complicated. See [Matrix Layouts](sec_matlayout) for
7582:   details on matrix layouts.

7584: .seealso: [](ch_matrices), `IS`, `Mat`, `MatGetOwnershipRanges()`, `MatSetValues()`, `MATELEMENTAL`, `MATSCALAPACK`
7585: @*/
7586: PetscErrorCode MatGetOwnershipIS(Mat A, IS *rows, IS *cols)
7587: {
7588:   PetscErrorCode (*f)(Mat, IS *, IS *);

7590:   PetscFunctionBegin;
7593:   MatCheckPreallocated(A, 1);
7594:   PetscCall(PetscObjectQueryFunction((PetscObject)A, "MatGetOwnershipIS_C", &f));
7595:   if (f) {
7596:     PetscCall((*f)(A, rows, cols));
7597:   } else { /* Create a standard row-based partition, each process is responsible for ALL columns in their row block */
7598:     if (rows) PetscCall(ISCreateStride(PETSC_COMM_SELF, A->rmap->n, A->rmap->rstart, 1, rows));
7599:     if (cols) PetscCall(ISCreateStride(PETSC_COMM_SELF, A->cmap->N, 0, 1, cols));
7600:   }
7601:   PetscFunctionReturn(PETSC_SUCCESS);
7602: }

7604: /*@
7605:   MatILUFactorSymbolic - Performs symbolic ILU factorization of a matrix obtained with `MatGetFactor()`
7606:   Uses levels of fill only, not drop tolerance. Use `MatLUFactorNumeric()`
7607:   to complete the factorization.

7609:   Collective

7611:   Input Parameters:
7612: + fact - the factorized matrix obtained with `MatGetFactor()`
7613: . mat  - the matrix
7614: . row  - row permutation
7615: . col  - column permutation
7616: - info - structure containing
7617: .vb
7618:       levels - number of levels of fill.
7619:       expected fill - as ratio of original fill.
7620:       1 or 0 - indicating force fill on diagonal (improves robustness for matrices
7621:                 missing diagonal entries)
7622: .ve

7624:   Level: developer

7626:   Notes:
7627:   See [Matrix Factorization](sec_matfactor) for additional information.

7629:   Most users should employ the `KSP` interface for linear solvers
7630:   instead of working directly with matrix algebra routines such as this.
7631:   See, e.g., `KSPCreate()`.

7633:   Uses the definition of level of fill as in Y. Saad, {cite}`saad2003`

7635:   Fortran Note:
7636:   A valid (non-null) `info` argument must be provided

7638: .seealso: [](ch_matrices), `Mat`, [Matrix Factorization](sec_matfactor), `MatGetFactor()`, `MatLUFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`,
7639:           `MatGetOrdering()`, `MatFactorInfo`
7640: @*/
7641: PetscErrorCode MatILUFactorSymbolic(Mat fact, Mat mat, IS row, IS col, const MatFactorInfo *info)
7642: {
7643:   PetscFunctionBegin;
7648:   PetscAssertPointer(info, 5);
7649:   PetscAssertPointer(fact, 1);
7650:   PetscCheck(info->levels >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Levels of fill negative %" PetscInt_FMT, (PetscInt)info->levels);
7651:   PetscCheck(info->fill >= 1.0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Expected fill less than 1.0 %g", (double)info->fill);
7652:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7653:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7654:   MatCheckPreallocated(mat, 2);

7656:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_ILUFactorSymbolic, mat, row, col, 0));
7657:   PetscUseTypeMethod(fact, ilufactorsymbolic, mat, row, col, info);
7658:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_ILUFactorSymbolic, mat, row, col, 0));
7659:   PetscFunctionReturn(PETSC_SUCCESS);
7660: }

7662: /*@
7663:   MatICCFactorSymbolic - Performs symbolic incomplete
7664:   Cholesky factorization for a symmetric matrix. Use
7665:   `MatCholeskyFactorNumeric()` to complete the factorization.

7667:   Collective

7669:   Input Parameters:
7670: + fact - the factorized matrix obtained with `MatGetFactor()`
7671: . mat  - the matrix to be factored
7672: . perm - row and column permutation
7673: - info - structure containing
7674: .vb
7675:       levels - number of levels of fill.
7676:       expected fill - as ratio of original fill.
7677: .ve

7679:   Level: developer

7681:   Notes:
7682:   Most users should employ the `KSP` interface for linear solvers
7683:   instead of working directly with matrix algebra routines such as this.
7684:   See, e.g., `KSPCreate()`.

7686:   This uses the definition of level of fill as in Y. Saad {cite}`saad2003`

7688:   Fortran Note:
7689:   A valid (non-null) `info` argument must be provided

7691: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatCholeskyFactorNumeric()`, `MatCholeskyFactor()`, `MatFactorInfo`
7692: @*/
7693: PetscErrorCode MatICCFactorSymbolic(Mat fact, Mat mat, IS perm, const MatFactorInfo *info)
7694: {
7695:   PetscFunctionBegin;
7699:   PetscAssertPointer(info, 4);
7700:   PetscAssertPointer(fact, 1);
7701:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7702:   PetscCheck(info->levels >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Levels negative %" PetscInt_FMT, (PetscInt)info->levels);
7703:   PetscCheck(info->fill >= 1.0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Expected fill less than 1.0 %g", (double)info->fill);
7704:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7705:   MatCheckPreallocated(mat, 2);

7707:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventBegin(MAT_ICCFactorSymbolic, mat, perm, 0, 0));
7708:   PetscUseTypeMethod(fact, iccfactorsymbolic, mat, perm, info);
7709:   if (!fact->trivialsymbolic) PetscCall(PetscLogEventEnd(MAT_ICCFactorSymbolic, mat, perm, 0, 0));
7710:   PetscFunctionReturn(PETSC_SUCCESS);
7711: }

7713: /*@
7714:   MatCreateSubMatrices - Extracts several submatrices from a matrix. If submat
7715:   points to an array of valid matrices, they may be reused to store the new
7716:   submatrices.

7718:   Collective

7720:   Input Parameters:
7721: + mat   - the matrix
7722: . n     - the number of submatrixes to be extracted (on this process, may be zero)
7723: . irow  - index set of rows to extract
7724: . icol  - index set of columns to extract
7725: - scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

7727:   Output Parameter:
7728: . submat - the array of submatrices

7730:   Level: advanced

7732:   Notes:
7733:   `MatCreateSubMatrices()` can extract ONLY sequential submatrices
7734:   (from both sequential and parallel matrices). Use `MatCreateSubMatrix()`
7735:   to extract a parallel submatrix.

7737:   Some matrix types place restrictions on the row and column
7738:   indices, such as that they be sorted or that they be equal to each other.
7739:   `MATSEQSBAIJ` inputs may produce `MATSEQBAIJ` submatrices when the row and column index sets do not preserve symmetry.

7741:   The index sets may not have duplicate entries.

7743:   When extracting submatrices from a parallel matrix, each process can
7744:   form a different submatrix by setting the rows and columns of its
7745:   individual index sets according to the local submatrix desired.

7747:   When finished using the submatrices, the user should destroy
7748:   them with `MatDestroySubMatrices()`.

7750:   `MAT_REUSE_MATRIX` can only be used when the nonzero structure of the
7751:   original matrix has not changed from that last call to `MatCreateSubMatrices()`.

7753:   This routine creates the matrices in submat; you should NOT create them before
7754:   calling it. It also allocates the array of matrix pointers submat.

7756:   For `MATBAIJ` matrices the index sets must respect the block structure, that is if they
7757:   request one row/column in a block, they must request all rows/columns that are in
7758:   that block. For example, if the block size is 2 you cannot request just row 0 and
7759:   column 0.

7761:   Fortran Note:
7762: .vb
7763:   Mat, pointer :: submat(:)
7764: .ve

7766: .seealso: [](ch_matrices), `Mat`, `MatDestroySubMatrices()`, `MatCreateSubMatrix()`, `MatGetRow()`, `MatGetDiagonal()`, `MatReuse`
7767: @*/
7768: PetscErrorCode MatCreateSubMatrices(Mat mat, PetscInt n, const IS irow[], const IS icol[], MatReuse scall, Mat *submat[])
7769: {
7770:   PetscInt  i;
7771:   PetscBool eq;

7773:   PetscFunctionBegin;
7776:   if (n) {
7777:     PetscAssertPointer(irow, 3);
7779:     PetscAssertPointer(icol, 4);
7781:   }
7782:   PetscAssertPointer(submat, 6);
7783:   if (n && scall == MAT_REUSE_MATRIX) {
7784:     PetscAssertPointer(*submat, 6);
7786:   }
7787:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7788:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7789:   MatCheckPreallocated(mat, 1);
7790:   PetscCall(PetscLogEventBegin(MAT_CreateSubMats, mat, 0, 0, 0));
7791:   PetscUseTypeMethod(mat, createsubmatrices, n, irow, icol, scall, submat);
7792:   PetscCall(PetscLogEventEnd(MAT_CreateSubMats, mat, 0, 0, 0));
7793:   for (i = 0; i < n; i++) {
7794:     (*submat)[i]->factortype = MAT_FACTOR_NONE; /* in case in place factorization was previously done on submatrix */
7795:     PetscCall(ISEqualUnsorted(irow[i], icol[i], &eq));
7796:     if (eq) PetscCall(MatPropagateSymmetryOptions(mat, (*submat)[i]));
7797: #if PetscDefined(HAVE_VIENNACL) || PetscDefined(HAVE_CUDA) || PetscDefined(HAVE_HIP)
7798:     if (mat->boundtocpu && mat->bindingpropagates) {
7799:       PetscCall(MatBindToCPU((*submat)[i], PETSC_TRUE));
7800:       PetscCall(MatSetBindingPropagates((*submat)[i], PETSC_TRUE));
7801:     }
7802: #endif
7803:   }
7804:   PetscFunctionReturn(PETSC_SUCCESS);
7805: }

7807: /*@
7808:   MatCreateSubMatricesMPI - Extracts MPI submatrices across a sub communicator of `mat` (by pairs of `IS` that may live on subcomms).

7810:   Collective

7812:   Input Parameters:
7813: + mat   - the matrix
7814: . n     - the number of submatrixes to be extracted
7815: . irow  - index set of rows to extract
7816: . icol  - index set of columns to extract
7817: - scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

7819:   Output Parameter:
7820: . submat - the array of submatrices

7822:   Level: advanced

7824:   Note:
7825:   This is used by `PCGASM`

7827: .seealso: [](ch_matrices), `Mat`, `PCGASM`, `MatCreateSubMatrices()`, `MatCreateSubMatrix()`, `MatGetRow()`, `MatGetDiagonal()`, `MatReuse`
7828: @*/
7829: PetscErrorCode MatCreateSubMatricesMPI(Mat mat, PetscInt n, const IS irow[], const IS icol[], MatReuse scall, Mat *submat[])
7830: {
7831:   PetscInt  i;
7832:   PetscBool eq;

7834:   PetscFunctionBegin;
7837:   if (n) {
7838:     PetscAssertPointer(irow, 3);
7840:     PetscAssertPointer(icol, 4);
7842:   }
7843:   PetscAssertPointer(submat, 6);
7844:   if (n && scall == MAT_REUSE_MATRIX) {
7845:     PetscAssertPointer(*submat, 6);
7847:   }
7848:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
7849:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7850:   MatCheckPreallocated(mat, 1);

7852:   PetscCall(PetscLogEventBegin(MAT_CreateSubMats, mat, 0, 0, 0));
7853:   PetscUseTypeMethod(mat, createsubmatricesmpi, n, irow, icol, scall, submat);
7854:   PetscCall(PetscLogEventEnd(MAT_CreateSubMats, mat, 0, 0, 0));
7855:   for (i = 0; i < n; i++) {
7856:     PetscCall(ISEqualUnsorted(irow[i], icol[i], &eq));
7857:     if (eq) PetscCall(MatPropagateSymmetryOptions(mat, (*submat)[i]));
7858:   }
7859:   PetscFunctionReturn(PETSC_SUCCESS);
7860: }

7862: /*@
7863:   MatDestroyMatrices - Destroys an array of matrices

7865:   Collective

7867:   Input Parameters:
7868: + n   - the number of local matrices
7869: - mat - the matrices (this is a pointer to the array of matrices)

7871:   Level: advanced

7873:   Notes:
7874:   Frees not only the matrices, but also the array that contains the matrices

7876:   For matrices obtained with  `MatCreateSubMatrices()` use `MatDestroySubMatrices()`

7878: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatDestroySubMatrices()`
7879: @*/
7880: PetscErrorCode MatDestroyMatrices(PetscInt n, Mat *mat[])
7881: {
7882:   PetscInt i;

7884:   PetscFunctionBegin;
7885:   if (!*mat) PetscFunctionReturn(PETSC_SUCCESS);
7886:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Trying to destroy negative number of matrices %" PetscInt_FMT, n);
7887:   PetscAssertPointer(mat, 2);

7889:   for (i = 0; i < n; i++) PetscCall(MatDestroy(&(*mat)[i]));

7891:   /* memory is allocated even if n = 0 */
7892:   PetscCall(PetscFree(*mat));
7893:   PetscFunctionReturn(PETSC_SUCCESS);
7894: }

7896: /*@
7897:   MatDestroySubMatrices - Destroys a set of matrices obtained with `MatCreateSubMatrices()`.

7899:   Collective

7901:   Input Parameters:
7902: + n   - the number of local matrices
7903: - mat - the matrices (this is a pointer to the array of matrices, to match the calling sequence of `MatCreateSubMatrices()`)

7905:   Level: advanced

7907:   Note:
7908:   Frees not only the matrices, but also the array that contains the matrices

7910: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatDestroyMatrices()`
7911: @*/
7912: PetscErrorCode MatDestroySubMatrices(PetscInt n, Mat *mat[])
7913: {
7914:   Mat mat0;

7916:   PetscFunctionBegin;
7917:   if (!*mat) PetscFunctionReturn(PETSC_SUCCESS);
7918:   /* mat[] is an array of length n+1, see MatCreateSubMatrices_xxx() */
7919:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Trying to destroy negative number of matrices %" PetscInt_FMT, n);
7920:   PetscAssertPointer(mat, 2);

7922:   mat0 = (*mat)[0];
7923:   if (mat0 && mat0->ops->destroysubmatrices) {
7924:     PetscCall((*mat0->ops->destroysubmatrices)(n, mat));
7925:   } else {
7926:     PetscCall(MatDestroyMatrices(n, mat));
7927:   }
7928:   PetscFunctionReturn(PETSC_SUCCESS);
7929: }

7931: /*@
7932:   MatGetSeqNonzeroStructure - Extracts the nonzero structure from a matrix and stores it, in its entirety, on each process

7934:   Collective

7936:   Input Parameter:
7937: . mat - the matrix

7939:   Output Parameter:
7940: . matstruct - the sequential matrix with the nonzero structure of `mat`

7942:   Level: developer

7944: .seealso: [](ch_matrices), `Mat`, `MatDestroySeqNonzeroStructure()`, `MatCreateSubMatrices()`, `MatDestroyMatrices()`
7945: @*/
7946: PetscErrorCode MatGetSeqNonzeroStructure(Mat mat, Mat *matstruct)
7947: {
7948:   PetscFunctionBegin;
7950:   PetscAssertPointer(matstruct, 2);

7953:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
7954:   MatCheckPreallocated(mat, 1);

7956:   PetscCall(PetscLogEventBegin(MAT_GetSeqNonzeroStructure, mat, 0, 0, 0));
7957:   PetscUseTypeMethod(mat, getseqnonzerostructure, matstruct);
7958:   PetscCall(PetscLogEventEnd(MAT_GetSeqNonzeroStructure, mat, 0, 0, 0));
7959:   PetscFunctionReturn(PETSC_SUCCESS);
7960: }

7962: /*@
7963:   MatDestroySeqNonzeroStructure - Destroys matrix obtained with `MatGetSeqNonzeroStructure()`.

7965:   Collective

7967:   Input Parameter:
7968: . mat - the matrix

7970:   Level: advanced

7972:   Note:
7973:   This is not needed, one can just call `MatDestroy()`

7975: .seealso: [](ch_matrices), `Mat`, `MatGetSeqNonzeroStructure()`
7976: @*/
7977: PetscErrorCode MatDestroySeqNonzeroStructure(Mat *mat)
7978: {
7979:   PetscFunctionBegin;
7980:   PetscAssertPointer(mat, 1);
7981:   PetscCall(MatDestroy(mat));
7982:   PetscFunctionReturn(PETSC_SUCCESS);
7983: }

7985: /*@
7986:   MatIncreaseOverlap - Given a set of submatrices indicated by index sets,
7987:   replaces the index sets by larger ones that represent submatrices with
7988:   additional overlap.

7990:   Collective

7992:   Input Parameters:
7993: + mat - the matrix
7994: . n   - the number of index sets
7995: . is  - the array of index sets (these index sets will changed during the call)
7996: - ov  - the additional overlap requested

7998:   Options Database Key:
7999: . -mat_increase_overlap_scalable - use a scalable algorithm to compute the overlap (supported by MPIAIJ matrix)

8001:   Level: developer

8003:   Note:
8004:   The computed overlap preserves the matrix block sizes when the blocks are square.
8005:   That is: if a matrix nonzero for a given block would increase the overlap all columns associated with
8006:   that block are included in the overlap regardless of whether each specific column would increase the overlap.

8008: .seealso: [](ch_matrices), `Mat`, `PCASM`, `MatSetBlockSize()`, `MatIncreaseOverlapSplit()`, `MatCreateSubMatrices()`
8009: @*/
8010: PetscErrorCode MatIncreaseOverlap(Mat mat, PetscInt n, IS is[], PetscInt ov)
8011: {
8012:   PetscInt i, bs, cbs;

8014:   PetscFunctionBegin;
8018:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must have one or more domains, you have %" PetscInt_FMT, n);
8019:   if (n) {
8020:     PetscAssertPointer(is, 3);
8022:   }
8023:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
8024:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
8025:   MatCheckPreallocated(mat, 1);

8027:   if (!ov || !n) PetscFunctionReturn(PETSC_SUCCESS);
8028:   PetscCall(PetscLogEventBegin(MAT_IncreaseOverlap, mat, 0, 0, 0));
8029:   PetscUseTypeMethod(mat, increaseoverlap, n, is, ov);
8030:   PetscCall(PetscLogEventEnd(MAT_IncreaseOverlap, mat, 0, 0, 0));
8031:   PetscCall(MatGetBlockSizes(mat, &bs, &cbs));
8032:   if (bs == cbs) {
8033:     for (i = 0; i < n; i++) PetscCall(ISSetBlockSize(is[i], bs));
8034:   }
8035:   PetscFunctionReturn(PETSC_SUCCESS);
8036: }

8038: PetscErrorCode MatIncreaseOverlapSplit_Single(Mat, IS *, PetscInt);

8040: /*@
8041:   MatIncreaseOverlapSplit - Given a set of submatrices indicated by index sets across
8042:   a sub communicator, replaces the index sets by larger ones that represent submatrices with
8043:   additional overlap.

8045:   Collective

8047:   Input Parameters:
8048: + mat - the matrix
8049: . n   - the number of index sets
8050: . is  - the array of index sets (these index sets will changed during the call)
8051: - ov  - the additional overlap requested

8053:   `   Options Database Key:
8054: . -mat_increase_overlap_scalable - use a scalable algorithm to compute the overlap (supported by MPIAIJ matrix)

8056:   Level: developer

8058: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatIncreaseOverlap()`
8059: @*/
8060: PetscErrorCode MatIncreaseOverlapSplit(Mat mat, PetscInt n, IS is[], PetscInt ov)
8061: {
8062:   PetscInt i;

8064:   PetscFunctionBegin;
8067:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Must have one or more domains, you have %" PetscInt_FMT, n);
8068:   if (n) {
8069:     PetscAssertPointer(is, 3);
8071:   }
8072:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
8073:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
8074:   MatCheckPreallocated(mat, 1);
8075:   if (!ov) PetscFunctionReturn(PETSC_SUCCESS);
8076:   PetscCall(PetscLogEventBegin(MAT_IncreaseOverlap, mat, 0, 0, 0));
8077:   for (i = 0; i < n; i++) PetscCall(MatIncreaseOverlapSplit_Single(mat, &is[i], ov));
8078:   PetscCall(PetscLogEventEnd(MAT_IncreaseOverlap, mat, 0, 0, 0));
8079:   PetscFunctionReturn(PETSC_SUCCESS);
8080: }

8082: /*@
8083:   MatGetBlockSize - Returns the matrix block size.

8085:   Not Collective

8087:   Input Parameter:
8088: . mat - the matrix

8090:   Output Parameter:
8091: . bs - block size

8093:   Level: intermediate

8095:   Notes:
8096:   Block row formats are `MATBAIJ` and `MATSBAIJ` ALWAYS have square block storage in the matrix.

8098:   If the block size has not been set yet this routine returns 1.

8100: .seealso: [](ch_matrices), `Mat`, `MATBAIJ`, `MATSBAIJ`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSizes()`
8101: @*/
8102: PetscErrorCode MatGetBlockSize(Mat mat, PetscInt *bs)
8103: {
8104:   PetscFunctionBegin;
8106:   PetscAssertPointer(bs, 2);
8107:   *bs = mat->rmap->bs;
8108:   PetscFunctionReturn(PETSC_SUCCESS);
8109: }

8111: /*@
8112:   MatGetBlockSizes - Returns the matrix block row and column sizes.

8114:   Not Collective

8116:   Input Parameter:
8117: . mat - the matrix

8119:   Output Parameters:
8120: + rbs - row block size
8121: - cbs - column block size

8123:   Level: intermediate

8125:   Notes:
8126:   Block row formats are `MATBAIJ` and `MATSBAIJ` ALWAYS have square block storage in the matrix.
8127:   If you pass a different block size for the columns than the rows, the row block size determines the square block storage.

8129:   If a block size has not been set yet this routine returns 1.

8131: .seealso: [](ch_matrices), `Mat`, `MATBAIJ`, `MATSBAIJ`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSize()`, `MatSetBlockSizes()`
8132: @*/
8133: PetscErrorCode MatGetBlockSizes(Mat mat, PetscInt *rbs, PetscInt *cbs)
8134: {
8135:   PetscFunctionBegin;
8137:   if (rbs) PetscAssertPointer(rbs, 2);
8138:   if (cbs) PetscAssertPointer(cbs, 3);
8139:   if (rbs) *rbs = mat->rmap->bs;
8140:   if (cbs) *cbs = mat->cmap->bs;
8141:   PetscFunctionReturn(PETSC_SUCCESS);
8142: }

8144: /*@
8145:   MatSetBlockSize - Sets the matrix block size.

8147:   Logically Collective

8149:   Input Parameters:
8150: + mat - the matrix
8151: - bs  - block size

8153:   Level: intermediate

8155:   Notes:
8156:   Block row formats are `MATBAIJ` and `MATSBAIJ` formats ALWAYS have square block storage in the matrix.
8157:   This must be called before `MatSetUp()` or MatXXXSetPreallocation() (or will default to 1) and the block size cannot be changed later.

8159:   For `MATAIJ` matrix format, this function can be called at a later stage, provided that the specified block size
8160:   is compatible with the matrix local sizes.

8162: .seealso: [](ch_matrices), `Mat`, `MATBAIJ`, `MATSBAIJ`, `MATAIJ`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`, `MatGetBlockSizes()`
8163: @*/
8164: PetscErrorCode MatSetBlockSize(Mat mat, PetscInt bs)
8165: {
8166:   PetscFunctionBegin;
8169:   PetscCall(MatSetBlockSizes(mat, bs, bs));
8170:   PetscFunctionReturn(PETSC_SUCCESS);
8171: }

8173: typedef struct {
8174:   PetscInt         n;
8175:   IS              *is;
8176:   Mat             *mat;
8177:   PetscObjectState nonzerostate;
8178:   Mat              C;
8179: } EnvelopeData;

8181: static PetscErrorCode EnvelopeDataDestroy(PetscCtxRt ptr)
8182: {
8183:   EnvelopeData *edata = *(EnvelopeData **)ptr;

8185:   PetscFunctionBegin;
8186:   for (PetscInt i = 0; i < edata->n; i++) PetscCall(ISDestroy(&edata->is[i]));
8187:   PetscCall(PetscFree(edata->is));
8188:   PetscCall(PetscFree(edata));
8189:   PetscFunctionReturn(PETSC_SUCCESS);
8190: }

8192: /*@
8193:   MatComputeVariableBlockEnvelope - Given a matrix whose nonzeros are in blocks along the diagonal this computes and stores
8194:   the sizes of these blocks in the matrix. An individual block may lie over several processes.

8196:   Collective

8198:   Input Parameter:
8199: . mat - the matrix

8201:   Level: intermediate

8203:   Notes:
8204:   There can be zeros within the blocks

8206:   The blocks can overlap between processes, including laying on more than two processes

8208: .seealso: [](ch_matrices), `Mat`, `MatInvertVariableBlockEnvelope()`, `MatSetVariableBlockSizes()`
8209: @*/
8210: PetscErrorCode MatComputeVariableBlockEnvelope(Mat mat)
8211: {
8212:   PetscInt        n, *sizes, *starts, i = 0, env = 0, tbs = 0, lblocks = 0, rstart, II, ln = 0, cnt = 0, cstart, cend;
8213:   PetscInt       *diag, *odiag, sc;
8214:   PetscInt       *seqv, *parv, *gidx;
8215:   const PetscInt *ia, *ja;
8216:   PetscBool       set, flag, done;
8217:   Mat             AA = mat, A;
8218:   MPI_Comm        comm;
8219:   PetscMPIInt     rank, size, tag;
8220:   MPI_Status      status;
8221:   PetscContainer  container;
8222:   EnvelopeData   *edata;
8223:   PetscSF         sf;
8224:   PetscLayout     layout;

8226:   PetscFunctionBegin;
8228:   PetscCall(MatIsSymmetricKnown(mat, &set, &flag));
8229:   if (!set || !flag) {
8230:     /* TODO: only needs nonzero structure of transpose */
8231:     PetscCall(MatTranspose(mat, MAT_INITIAL_MATRIX, &AA));
8232:     PetscCall(MatAXPY(AA, 1.0, mat, DIFFERENT_NONZERO_PATTERN));
8233:   }
8234:   PetscCall(MatAIJGetLocalMat(AA, &A));
8235:   PetscCall(MatGetRowIJ(A, 0, PETSC_FALSE, PETSC_FALSE, &n, &ia, &ja, &done));
8236:   PetscCheck(done, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Unable to get IJ structure from matrix");

8238:   PetscCall(MatGetLocalSize(mat, &n, NULL));
8239:   PetscCall(PetscObjectGetNewTag((PetscObject)mat, &tag));
8240:   PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
8241:   PetscCallMPI(MPI_Comm_size(comm, &size));
8242:   PetscCallMPI(MPI_Comm_rank(comm, &rank));

8244:   PetscCall(PetscMalloc2(n, &sizes, n, &starts));

8246:   if (rank > 0) {
8247:     PetscCallMPI(MPI_Recv(&env, 1, MPIU_INT, rank - 1, tag, comm, &status));
8248:     PetscCallMPI(MPI_Recv(&tbs, 1, MPIU_INT, rank - 1, tag, comm, &status));
8249:   }
8250:   PetscCall(MatGetOwnershipRange(mat, &rstart, NULL));
8251:   for (i = 0; i < n; i++) {
8252:     env = PetscMax(env, ja[ia[i + 1] - 1]);
8253:     II  = rstart + i;
8254:     if (env == II) {
8255:       starts[lblocks]  = tbs;
8256:       sizes[lblocks++] = 1 + II - tbs;
8257:       tbs              = 1 + II;
8258:     }
8259:   }
8260:   if (rank < size - 1) {
8261:     PetscCallMPI(MPI_Send(&env, 1, MPIU_INT, rank + 1, tag, comm));
8262:     PetscCallMPI(MPI_Send(&tbs, 1, MPIU_INT, rank + 1, tag, comm));
8263:   }

8265:   PetscCall(MatRestoreRowIJ(A, 0, PETSC_FALSE, PETSC_FALSE, &n, &ia, &ja, &done));
8266:   if (!set || !flag) PetscCall(MatDestroy(&AA));
8267:   PetscCall(MatDestroy(&A));

8269:   PetscCall(PetscNew(&edata));
8270:   PetscCall(MatGetNonzeroState(mat, &edata->nonzerostate));
8271:   edata->n = lblocks;
8272:   /* create IS needed for extracting blocks from the original matrix */
8273:   PetscCall(PetscMalloc1(lblocks, &edata->is));
8274:   for (PetscInt i = 0; i < lblocks; i++) PetscCall(ISCreateStride(PETSC_COMM_SELF, sizes[i], starts[i], 1, &edata->is[i]));

8276:   /* Create the resulting inverse matrix nonzero structure with preallocation information */
8277:   PetscCall(MatCreate(PetscObjectComm((PetscObject)mat), &edata->C));
8278:   PetscCall(MatSetSizes(edata->C, mat->rmap->n, mat->cmap->n, mat->rmap->N, mat->cmap->N));
8279:   PetscCall(MatSetBlockSizesFromMats(edata->C, mat, mat));
8280:   PetscCall(MatSetType(edata->C, MATAIJ));

8282:   /* Communicate the start and end of each row, from each block to the correct rank */
8283:   for (PetscInt i = 0; i < lblocks; i++) ln += sizes[i];
8284:   PetscCall(PetscCalloc3(2 * ln, &seqv, 2 * mat->rmap->n, &parv, 2 * ln, &gidx));
8285:   for (PetscInt i = 0; i < lblocks; i++) {
8286:     for (PetscInt j = 0; j < sizes[i]; j++) {
8287:       seqv[cnt]     = starts[i];
8288:       seqv[cnt + 1] = starts[i] + sizes[i];
8289:       cnt += 2;
8290:     }
8291:   }
8292:   PetscCallMPI(MPI_Scan(&cnt, &sc, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)mat)));
8293:   sc -= cnt;
8294:   for (PetscInt i = 0; i < cnt; i++) gidx[i] = sc + i;
8295:   PetscCall(PetscLayoutCreateFromSizes(PetscObjectComm((PetscObject)mat), 2 * mat->rmap->n, 2 * mat->rmap->N, 1, &layout));
8296:   PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)mat), &sf));
8297:   PetscCall(PetscSFSetGraphLayout(sf, layout, cnt, NULL, PETSC_COPY_VALUES, gidx));
8298:   PetscCall(PetscLayoutDestroy(&layout));
8299:   PetscCall(PetscSFReduceBegin(sf, MPIU_INT, seqv, parv, MPI_REPLACE));
8300:   PetscCall(PetscSFReduceEnd(sf, MPIU_INT, seqv, parv, MPI_REPLACE));
8301:   PetscCall(PetscSFDestroy(&sf));
8302:   PetscCall(MatGetOwnershipRangeColumn(mat, &cstart, &cend));
8303:   PetscCall(PetscMalloc2(mat->rmap->n, &diag, mat->rmap->n, &odiag));
8304:   cnt = 0;
8305:   PetscCall(MatGetSize(mat, NULL, &n));
8306:   for (PetscInt i = 0; i < mat->rmap->n; i++) {
8307:     PetscInt start, end, d = 0, od = 0;

8309:     start = parv[cnt];
8310:     end   = parv[cnt + 1];
8311:     cnt += 2;

8313:     if (start < cstart) {
8314:       od += cstart - start + n - cend;
8315:       d += cend - cstart;
8316:     } else if (start < cend) {
8317:       od += n - cend;
8318:       d += cend - start;
8319:     } else od += n - start;
8320:     if (end <= cstart) {
8321:       od -= cstart - end + n - cend;
8322:       d -= cend - cstart;
8323:     } else if (end < cend) {
8324:       od -= n - cend;
8325:       d -= cend - end;
8326:     } else od -= n - end;

8328:     odiag[i] = od;
8329:     diag[i]  = d;
8330:   }
8331:   PetscCall(PetscFree3(seqv, parv, gidx));
8332:   PetscCall(MatXAIJSetPreallocation(edata->C, mat->rmap->bs, diag, odiag, NULL, NULL));
8333:   PetscCall(PetscFree2(diag, odiag));
8334:   PetscCall(PetscFree2(sizes, starts));

8336:   PetscCall(PetscContainerCreate(PETSC_COMM_SELF, &container));
8337:   PetscCall(PetscContainerSetPointer(container, edata));
8338:   PetscCall(PetscContainerSetCtxDestroy(container, EnvelopeDataDestroy));
8339:   PetscCall(PetscObjectCompose((PetscObject)mat, "EnvelopeData", (PetscObject)container));
8340:   PetscCall(PetscObjectDereference((PetscObject)container));
8341:   PetscFunctionReturn(PETSC_SUCCESS);
8342: }

8344: /*@
8345:   MatInvertVariableBlockEnvelope - set matrix C to be the inverted block diagonal of matrix A

8347:   Collective

8349:   Input Parameters:
8350: + A     - the matrix
8351: - reuse - indicates if the `C` matrix was obtained from a previous call to this routine

8353:   Output Parameter:
8354: . C - matrix with inverted block diagonal of `A`

8356:   Level: advanced

8358:   Note:
8359:   For efficiency the matrix `A` should have all the nonzero entries clustered in smallish blocks along the diagonal.

8361: .seealso: [](ch_matrices), `Mat`, `MatInvertBlockDiagonal()`, `MatComputeBlockDiagonal()`
8362: @*/
8363: PetscErrorCode MatInvertVariableBlockEnvelope(Mat A, MatReuse reuse, Mat *C)
8364: {
8365:   PetscContainer   container;
8366:   EnvelopeData    *edata;
8367:   PetscObjectState nonzerostate;

8369:   PetscFunctionBegin;
8370:   PetscCall(PetscObjectQuery((PetscObject)A, "EnvelopeData", (PetscObject *)&container));
8371:   if (!container) {
8372:     PetscCall(MatComputeVariableBlockEnvelope(A));
8373:     PetscCall(PetscObjectQuery((PetscObject)A, "EnvelopeData", (PetscObject *)&container));
8374:   }
8375:   PetscCall(PetscContainerGetPointer(container, &edata));
8376:   PetscCall(MatGetNonzeroState(A, &nonzerostate));
8377:   PetscCheck(nonzerostate <= edata->nonzerostate, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot handle changes to matrix nonzero structure");
8378:   PetscCheck(reuse != MAT_REUSE_MATRIX || *C == edata->C, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "C matrix must be the same as previously output");

8380:   PetscCall(MatCreateSubMatrices(A, edata->n, edata->is, edata->is, MAT_INITIAL_MATRIX, &edata->mat));
8381:   *C = edata->C;

8383:   for (PetscInt i = 0; i < edata->n; i++) {
8384:     Mat          D;
8385:     PetscScalar *dvalues;

8387:     PetscCall(MatConvert(edata->mat[i], MATSEQDENSE, MAT_INITIAL_MATRIX, &D));
8388:     PetscCall(MatSetOption(*C, MAT_ROW_ORIENTED, PETSC_FALSE));
8389:     PetscCall(MatSeqDenseInvert(D));
8390:     PetscCall(MatDenseGetArray(D, &dvalues));
8391:     PetscCall(MatSetValuesIS(*C, edata->is[i], edata->is[i], dvalues, INSERT_VALUES));
8392:     PetscCall(MatDestroy(&D));
8393:   }
8394:   PetscCall(MatDestroySubMatrices(edata->n, &edata->mat));
8395:   PetscCall(MatAssemblyBegin(*C, MAT_FINAL_ASSEMBLY));
8396:   PetscCall(MatAssemblyEnd(*C, MAT_FINAL_ASSEMBLY));
8397:   PetscFunctionReturn(PETSC_SUCCESS);
8398: }

8400: /*@
8401:   MatSetVariableBlockSizes - Sets diagonal point-blocks of the matrix that need not be of the same size

8403:   Not Collective

8405:   Input Parameters:
8406: + mat     - the matrix
8407: . nblocks - the number of blocks on this process, each block can only exist on a single MPI process
8408: - bsizes  - the block sizes

8410:   Level: intermediate

8412:   Note:
8413:   Currently used by `PCVPBJACOBI` for `MATAIJ` matrices

8415: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`, `MatGetBlockSizes()`, `MatGetVariableBlockSizes()`,
8416:           `MatComputeVariableBlockEnvelope()`, `PCVPBJACOBI`
8417: @*/
8418: PetscErrorCode MatSetVariableBlockSizes(Mat mat, PetscInt nblocks, const PetscInt bsizes[])
8419: {
8420:   PetscInt ncnt = 0, nlocal;

8422:   PetscFunctionBegin;
8424:   PetscCall(MatGetLocalSize(mat, &nlocal, NULL));
8425:   PetscCheck(nblocks >= 0 && nblocks <= nlocal, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Number of local blocks %" PetscInt_FMT " is not in [0, %" PetscInt_FMT "]", nblocks, nlocal);
8426:   for (PetscInt i = 0; i < nblocks; i++) ncnt += bsizes[i];
8427:   PetscCheck(ncnt == nlocal, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Sum of local block sizes %" PetscInt_FMT " does not equal local size of matrix %" PetscInt_FMT, ncnt, nlocal);
8428:   PetscCall(PetscFree(mat->bsizes));
8429:   mat->nblocks = nblocks;
8430:   PetscCall(PetscMalloc1(nblocks, &mat->bsizes));
8431:   PetscCall(PetscArraycpy(mat->bsizes, bsizes, nblocks));
8432:   PetscFunctionReturn(PETSC_SUCCESS);
8433: }

8435: /*@
8436:   MatGetVariableBlockSizes - Gets a diagonal blocks of the matrix that need not be of the same size

8438:   Not Collective; No Fortran Support

8440:   Input Parameter:
8441: . mat - the matrix

8443:   Output Parameters:
8444: + nblocks - the number of blocks on this process
8445: - bsizes  - the block sizes

8447:   Level: intermediate

8449: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`, `MatGetBlockSizes()`, `MatSetVariableBlockSizes()`, `MatComputeVariableBlockEnvelope()`
8450: @*/
8451: PetscErrorCode MatGetVariableBlockSizes(Mat mat, PetscInt *nblocks, const PetscInt *bsizes[])
8452: {
8453:   PetscFunctionBegin;
8455:   if (nblocks) *nblocks = mat->nblocks;
8456:   if (bsizes) *bsizes = mat->bsizes;
8457:   PetscFunctionReturn(PETSC_SUCCESS);
8458: }

8460: /*@
8461:   MatSelectVariableBlockSizes - When creating a submatrix, pass on the variable block sizes

8463:   Not Collective

8465:   Input Parameters:
8466: + subA  - the submatrix
8467: . A     - the original matrix
8468: - isrow - The `IS` of selected rows for the submatrix, must be sorted

8470:   Level: developer

8472:   Note:
8473:   If the index set is not sorted or contains off-process entries, this function will do nothing.

8475: .seealso: [](ch_matrices), `Mat`, `MatSetVariableBlockSizes()`, `MatComputeVariableBlockEnvelope()`
8476: @*/
8477: PetscErrorCode MatSelectVariableBlockSizes(Mat subA, Mat A, IS isrow)
8478: {
8479:   const PetscInt *rows;
8480:   PetscInt        n, rStart, rEnd, Nb = 0;
8481:   PetscBool       flg = A->bsizes ? PETSC_TRUE : PETSC_FALSE;

8483:   PetscFunctionBegin;
8484:   // The code for block size extraction does not support an unsorted IS
8485:   if (flg) PetscCall(ISSorted(isrow, &flg));
8486:   // We don't support originally off-diagonal blocks
8487:   if (flg) {
8488:     PetscCall(MatGetOwnershipRange(A, &rStart, &rEnd));
8489:     PetscCall(ISGetLocalSize(isrow, &n));
8490:     PetscCall(ISGetIndices(isrow, &rows));
8491:     for (PetscInt i = 0; i < n && flg; ++i) {
8492:       if (rows[i] < rStart || rows[i] >= rEnd) flg = PETSC_FALSE;
8493:     }
8494:     PetscCall(ISRestoreIndices(isrow, &rows));
8495:   }
8496:   // quiet return if we can't extract block size
8497:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &flg, 1, MPI_C_BOOL, MPI_LAND, PetscObjectComm((PetscObject)subA)));
8498:   if (!flg) PetscFunctionReturn(PETSC_SUCCESS);

8500:   // extract block sizes
8501:   PetscCall(ISGetIndices(isrow, &rows));
8502:   for (PetscInt b = 0, gr = rStart, i = 0; b < A->nblocks; ++b) {
8503:     PetscBool occupied = PETSC_FALSE;

8505:     for (PetscInt br = 0; br < A->bsizes[b]; ++br) {
8506:       const PetscInt row = gr + br;

8508:       if (i == n) break;
8509:       if (rows[i] == row) {
8510:         occupied = PETSC_TRUE;
8511:         ++i;
8512:       }
8513:       while (i < n && rows[i] < row) ++i;
8514:     }
8515:     gr += A->bsizes[b];
8516:     if (occupied) ++Nb;
8517:   }
8518:   subA->nblocks = Nb;
8519:   PetscCall(PetscFree(subA->bsizes));
8520:   PetscCall(PetscMalloc1(subA->nblocks, &subA->bsizes));
8521:   PetscInt sb = 0;
8522:   for (PetscInt b = 0, gr = rStart, i = 0; b < A->nblocks; ++b) {
8523:     if (sb < subA->nblocks) subA->bsizes[sb] = 0;
8524:     for (PetscInt br = 0; br < A->bsizes[b]; ++br) {
8525:       const PetscInt row = gr + br;

8527:       if (i == n) break;
8528:       if (rows[i] == row) {
8529:         ++subA->bsizes[sb];
8530:         ++i;
8531:       }
8532:       while (i < n && rows[i] < row) ++i;
8533:     }
8534:     gr += A->bsizes[b];
8535:     if (sb < subA->nblocks && subA->bsizes[sb]) ++sb;
8536:   }
8537:   PetscCheck(sb == subA->nblocks, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Invalid number of blocks %" PetscInt_FMT " != %" PetscInt_FMT, sb, subA->nblocks);
8538:   PetscInt nlocal, ncnt = 0;
8539:   PetscCall(MatGetLocalSize(subA, &nlocal, NULL));
8540:   PetscCheck(subA->nblocks >= 0 && subA->nblocks <= nlocal, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Number of local blocks %" PetscInt_FMT " is not in [0, %" PetscInt_FMT "]", subA->nblocks, nlocal);
8541:   for (PetscInt i = 0; i < subA->nblocks; i++) ncnt += subA->bsizes[i];
8542:   PetscCheck(ncnt == nlocal, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "Sum of local block sizes %" PetscInt_FMT " does not equal local size of matrix %" PetscInt_FMT, ncnt, nlocal);
8543:   PetscCall(ISRestoreIndices(isrow, &rows));
8544:   PetscFunctionReturn(PETSC_SUCCESS);
8545: }

8547: /*@
8548:   MatSetBlockSizes - Sets the matrix block row and column sizes.

8550:   Logically Collective

8552:   Input Parameters:
8553: + mat - the matrix
8554: . rbs - row block size
8555: - cbs - column block size

8557:   Level: intermediate

8559:   Notes:
8560:   Block row formats are `MATBAIJ` and  `MATSBAIJ`. These formats ALWAYS have square block storage in the matrix.
8561:   If you pass a different block size for the columns than the rows, the row block size determines the square block storage.
8562:   This must be called before `MatSetUp()` or MatXXXSetPreallocation() (or will default to 1) and the block size cannot be changed later.

8564:   For `MATAIJ` matrix this function can be called at a later stage, provided that the specified block sizes
8565:   are compatible with the matrix local sizes.

8567:   The row and column block size determine the blocksize of the "row" and "column" vectors returned by `MatCreateVecs()`.

8569: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSize()`, `MatGetBlockSizes()`
8570: @*/
8571: PetscErrorCode MatSetBlockSizes(Mat mat, PetscInt rbs, PetscInt cbs)
8572: {
8573:   PetscFunctionBegin;
8577:   PetscTryTypeMethod(mat, setblocksizes, rbs, cbs);
8578:   if (mat->rmap->refcnt) {
8579:     ISLocalToGlobalMapping l2g  = NULL;
8580:     PetscLayout            nmap = NULL;

8582:     PetscCall(PetscLayoutDuplicate(mat->rmap, &nmap));
8583:     if (mat->rmap->mapping) PetscCall(ISLocalToGlobalMappingDuplicate(mat->rmap->mapping, &l2g));
8584:     PetscCall(PetscLayoutDestroy(&mat->rmap));
8585:     mat->rmap          = nmap;
8586:     mat->rmap->mapping = l2g;
8587:   }
8588:   if (mat->cmap->refcnt) {
8589:     ISLocalToGlobalMapping l2g  = NULL;
8590:     PetscLayout            nmap = NULL;

8592:     PetscCall(PetscLayoutDuplicate(mat->cmap, &nmap));
8593:     if (mat->cmap->mapping) PetscCall(ISLocalToGlobalMappingDuplicate(mat->cmap->mapping, &l2g));
8594:     PetscCall(PetscLayoutDestroy(&mat->cmap));
8595:     mat->cmap          = nmap;
8596:     mat->cmap->mapping = l2g;
8597:   }
8598:   PetscCall(PetscLayoutSetBlockSize(mat->rmap, rbs));
8599:   PetscCall(PetscLayoutSetBlockSize(mat->cmap, cbs));
8600:   PetscFunctionReturn(PETSC_SUCCESS);
8601: }

8603: /*@
8604:   MatSetBlockSizesFromMats - Sets the matrix block row and column sizes to match a pair of matrices

8606:   Logically Collective

8608:   Input Parameters:
8609: + mat     - the matrix
8610: . fromRow - matrix from which to copy row block size
8611: - fromCol - matrix from which to copy column block size (can be same as `fromRow`)

8613:   Level: developer

8615: .seealso: [](ch_matrices), `Mat`, `MatCreateSeqBAIJ()`, `MatCreateBAIJ()`, `MatGetBlockSize()`, `MatSetBlockSizes()`
8616: @*/
8617: PetscErrorCode MatSetBlockSizesFromMats(Mat mat, Mat fromRow, Mat fromCol)
8618: {
8619:   PetscFunctionBegin;
8623:   PetscTryTypeMethod(mat, setblocksizes, fromRow->rmap->bs, fromCol->cmap->bs);
8624:   PetscCall(PetscLayoutSetBlockSize(mat->rmap, fromRow->rmap->bs));
8625:   PetscCall(PetscLayoutSetBlockSize(mat->cmap, fromCol->cmap->bs));
8626:   PetscFunctionReturn(PETSC_SUCCESS);
8627: }

8629: /*@
8630:   MatResidual - Default routine to calculate the residual $r = b - Ax$

8632:   Collective

8634:   Input Parameters:
8635: + mat - the matrix
8636: . b   - the right-hand-side
8637: - x   - the approximate solution

8639:   Output Parameter:
8640: . r - location to store the residual

8642:   Level: developer

8644: .seealso: [](ch_matrices), `Mat`, `MatMult()`, `MatMultAdd()`, `PCMGSetResidual()`
8645: @*/
8646: PetscErrorCode MatResidual(Mat mat, Vec b, Vec x, Vec r)
8647: {
8648:   PetscFunctionBegin;
8654:   MatCheckPreallocated(mat, 1);
8655:   PetscCall(PetscLogEventBegin(MAT_Residual, mat, 0, 0, 0));
8656:   if (!mat->ops->residual) {
8657:     PetscCall(MatMult(mat, x, r));
8658:     PetscCall(VecAYPX(r, -1.0, b));
8659:   } else {
8660:     PetscUseTypeMethod(mat, residual, b, x, r);
8661:   }
8662:   PetscCall(PetscLogEventEnd(MAT_Residual, mat, 0, 0, 0));
8663:   PetscFunctionReturn(PETSC_SUCCESS);
8664: }

8666: /*@
8667:   MatGetRowIJ - Returns the compressed row storage i and j indices for the local rows of a sparse matrix

8669:   Collective

8671:   Input Parameters:
8672: + mat             - the matrix
8673: . shift           - 0 or 1 indicating we want the indices starting at 0 or 1
8674: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8675: - inodecompressed - `PETSC_TRUE` or `PETSC_FALSE`  indicating if the nonzero structure of the
8676:                     inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8677:                     always used.

8679:   Output Parameters:
8680: + n    - number of local rows in the (possibly compressed) matrix, use `NULL` if not needed
8681: . ia   - the row pointers; that is ia[0] = 0, ia[row] = ia[row-1] + number of elements in that row of the matrix, use `NULL` if not needed
8682: . ja   - the column indices, use `NULL` if not needed
8683: - done - indicates if the routine actually worked and returned appropriate `ia` and `ja` arrays; callers
8684:          are responsible for handling the case when done is `PETSC_FALSE` and `ia` and `ja` are not provided

8686:   Level: developer

8688:   Notes:
8689:   You CANNOT change any of the `ia` or `ja` values.

8691:   Use `MatRestoreRowIJ()` when you are finished accessing the `ia` and `ja` values.

8693:   Fortran Notes:
8694:   Use
8695: .vb
8696:     PetscInt, pointer :: ia(:),ja(:)
8697:     call MatGetRowIJ(mat,shift,symmetric,inodecompressed,n,ia,ja,done,ierr)
8698:     ! Access the ith and jth entries via ia(i) and ja(j)
8699: .ve

8701: .seealso: [](ch_matrices), `Mat`, `MATAIJ`, `MatGetColumnIJ()`, `MatRestoreRowIJ()`, `MatSeqAIJGetArray()`
8702: @*/
8703: PetscErrorCode MatGetRowIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8704: {
8705:   PetscFunctionBegin;
8708:   if (n) PetscAssertPointer(n, 5);
8709:   if (ia) PetscAssertPointer(ia, 6);
8710:   if (ja) PetscAssertPointer(ja, 7);
8711:   if (done) PetscAssertPointer(done, 8);
8712:   MatCheckPreallocated(mat, 1);
8713:   if (!mat->ops->getrowij && done) *done = PETSC_FALSE;
8714:   else {
8715:     if (done) *done = PETSC_TRUE;
8716:     PetscCall(PetscLogEventBegin(MAT_GetRowIJ, mat, 0, 0, 0));
8717:     PetscUseTypeMethod(mat, getrowij, shift, symmetric, inodecompressed, n, ia, ja, done);
8718:     PetscCall(PetscLogEventEnd(MAT_GetRowIJ, mat, 0, 0, 0));
8719:   }
8720:   PetscFunctionReturn(PETSC_SUCCESS);
8721: }

8723: /*@
8724:   MatGetColumnIJ - Returns the compressed column storage i and j indices for sequential matrices.

8726:   Collective

8728:   Input Parameters:
8729: + mat             - the matrix
8730: . shift           - 1 or zero indicating we want the indices starting at 0 or 1
8731: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be
8732:                     symmetrized
8733: - inodecompressed - `PETSC_TRUE` or `PETSC_FALSE` indicating if the nonzero structure of the
8734:                     inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8735:                     always used.

8737:   Output Parameters:
8738: + n    - number of columns in the (possibly compressed) matrix
8739: . ia   - the column pointers; that is ia[0] = 0, ia[col] = i[col-1] + number of elements in that col of the matrix
8740: . ja   - the row indices
8741: - done - `PETSC_TRUE` or `PETSC_FALSE`, indicating whether the values have been returned

8743:   Level: developer

8745: .seealso: [](ch_matrices), `Mat`, `MatGetRowIJ()`, `MatRestoreColumnIJ()`
8746: @*/
8747: PetscErrorCode MatGetColumnIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8748: {
8749:   PetscFunctionBegin;
8752:   PetscAssertPointer(n, 5);
8753:   if (ia) PetscAssertPointer(ia, 6);
8754:   if (ja) PetscAssertPointer(ja, 7);
8755:   PetscAssertPointer(done, 8);
8756:   MatCheckPreallocated(mat, 1);
8757:   if (!mat->ops->getcolumnij) *done = PETSC_FALSE;
8758:   else {
8759:     *done = PETSC_TRUE;
8760:     PetscUseTypeMethod(mat, getcolumnij, shift, symmetric, inodecompressed, n, ia, ja, done);
8761:   }
8762:   PetscFunctionReturn(PETSC_SUCCESS);
8763: }

8765: /*@
8766:   MatRestoreRowIJ - Call after you are completed with the ia,ja indices obtained with `MatGetRowIJ()`.

8768:   Collective

8770:   Input Parameters:
8771: + mat             - the matrix
8772: . shift           - 1 or zero indicating we want the indices starting at 0 or 1
8773: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8774: . inodecompressed - `PETSC_TRUE` or `PETSC_FALSE` indicating if the nonzero structure of the
8775:                     inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8776:                     always used.
8777: . n               - size of (possibly compressed) matrix, or `NULL`
8778: . ia              - the row pointers, or `NULL`
8779: - ja              - the column indices, or `NULL`

8781:   Output Parameter:
8782: . done - `PETSC_TRUE` or `PETSC_FALSE` indicated that the values have been returned

8784:   Level: developer

8786:   Note:
8787:   This routine zeros out `n`, `ia`, and `ja` if they are provided. Use of `ia` or `ja` after `MatRestoreRowIJ()` is always invalid.

8789: .seealso: [](ch_matrices), `Mat`, `MatGetRowIJ()`, `MatRestoreColumnIJ()`
8790: @*/
8791: PetscErrorCode MatRestoreRowIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8792: {
8793:   PetscFunctionBegin;
8796:   if (ia) PetscAssertPointer(ia, 6);
8797:   if (ja) PetscAssertPointer(ja, 7);
8798:   if (done) PetscAssertPointer(done, 8);
8799:   MatCheckPreallocated(mat, 1);

8801:   if (!mat->ops->restorerowij && done) *done = PETSC_FALSE;
8802:   else {
8803:     if (done) *done = PETSC_TRUE;
8804:     PetscUseTypeMethod(mat, restorerowij, shift, symmetric, inodecompressed, n, ia, ja, done);
8805:     if (n) *n = 0;
8806:     if (ia) *ia = NULL;
8807:     if (ja) *ja = NULL;
8808:   }
8809:   PetscFunctionReturn(PETSC_SUCCESS);
8810: }

8812: /*@
8813:   MatRestoreColumnIJ - Call after you are completed with the ia,ja indices obtained with `MatGetColumnIJ()`.

8815:   Collective

8817:   Input Parameters:
8818: + mat             - the matrix
8819: . shift           - 1 or zero indicating we want the indices starting at 0 or 1
8820: . symmetric       - `PETSC_TRUE` or `PETSC_FALSE` indicating the matrix data structure should be symmetrized
8821: - inodecompressed - `PETSC_TRUE` or `PETSC_FALSE` indicating if the nonzero structure of the
8822:                     inodes or the nonzero elements is wanted. For `MATBAIJ` matrices the compressed version is
8823:                     always used.

8825:   Output Parameters:
8826: + n    - size of (possibly compressed) matrix
8827: . ia   - the column pointers
8828: . ja   - the row indices
8829: - done - `PETSC_TRUE` or `PETSC_FALSE` indicated that the values have been returned

8831:   Level: developer

8833: .seealso: [](ch_matrices), `Mat`, `MatGetColumnIJ()`, `MatRestoreRowIJ()`
8834: @*/
8835: PetscErrorCode MatRestoreColumnIJ(Mat mat, PetscInt shift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscBool *done)
8836: {
8837:   PetscFunctionBegin;
8840:   if (ia) PetscAssertPointer(ia, 6);
8841:   if (ja) PetscAssertPointer(ja, 7);
8842:   PetscAssertPointer(done, 8);
8843:   MatCheckPreallocated(mat, 1);

8845:   if (!mat->ops->restorecolumnij) *done = PETSC_FALSE;
8846:   else {
8847:     *done = PETSC_TRUE;
8848:     PetscUseTypeMethod(mat, restorecolumnij, shift, symmetric, inodecompressed, n, ia, ja, done);
8849:     if (n) *n = 0;
8850:     if (ia) *ia = NULL;
8851:     if (ja) *ja = NULL;
8852:   }
8853:   PetscFunctionReturn(PETSC_SUCCESS);
8854: }

8856: /*@
8857:   MatColoringPatch - Utility routine used inside matrix coloring routines that use `MatGetRowIJ()` and/or
8858:   `MatGetColumnIJ()`.

8860:   Collective

8862:   Input Parameters:
8863: + mat        - the matrix
8864: . ncolors    - maximum color value
8865: . n          - number of entries in `colorarray`
8866: - colorarray - array indicating color for each column

8868:   Output Parameter:
8869: . iscoloring - coloring generated using `colorarray` information

8871:   Level: developer

8873: .seealso: [](ch_matrices), `Mat`, `MatGetRowIJ()`, `MatGetColumnIJ()`
8874: @*/
8875: PetscErrorCode MatColoringPatch(Mat mat, PetscInt ncolors, PetscInt n, ISColoringValue colorarray[], ISColoring *iscoloring)
8876: {
8877:   PetscFunctionBegin;
8880:   PetscAssertPointer(colorarray, 4);
8881:   PetscAssertPointer(iscoloring, 5);
8882:   MatCheckPreallocated(mat, 1);

8884:   if (!mat->ops->coloringpatch) {
8885:     PetscCall(ISColoringCreate(PetscObjectComm((PetscObject)mat), ncolors, n, colorarray, PETSC_OWN_POINTER, iscoloring));
8886:   } else {
8887:     PetscUseTypeMethod(mat, coloringpatch, ncolors, n, colorarray, iscoloring);
8888:   }
8889:   PetscFunctionReturn(PETSC_SUCCESS);
8890: }

8892: /*@
8893:   MatSetUnfactored - Resets a factored matrix to be treated as unfactored.

8895:   Logically Collective

8897:   Input Parameter:
8898: . mat - the factored matrix to be reset

8900:   Level: developer

8902:   Notes:
8903:   This routine should be used only with factored matrices formed by in-place
8904:   factorization via ILU(0) (or by in-place LU factorization for the `MATSEQDENSE`
8905:   format). This option can save memory, for example, when solving nonlinear
8906:   systems with a matrix-free Newton-Krylov method and a matrix-based, in-place
8907:   ILU(0) preconditioner.

8909:   One can specify in-place ILU(0) factorization by calling
8910: .vb
8911:      PCType(pc,PCILU);
8912:      PCFactorSeUseInPlace(pc);
8913: .ve
8914:   or by using the options -pc_type ilu -pc_factor_in_place

8916:   In-place factorization ILU(0) can also be used as a local
8917:   solver for the blocks within the block Jacobi or additive Schwarz
8918:   methods (runtime option: -sub_pc_factor_in_place). See Users-Manual: ch_pc
8919:   for details on setting local solver options.

8921:   Most users should employ the `KSP` interface for linear solvers
8922:   instead of working directly with matrix algebra routines such as this.
8923:   See, e.g., `KSPCreate()`.

8925: .seealso: [](ch_matrices), `Mat`, `PCFactorSetUseInPlace()`, `PCFactorGetUseInPlace()`
8926: @*/
8927: PetscErrorCode MatSetUnfactored(Mat mat)
8928: {
8929:   PetscFunctionBegin;
8932:   MatCheckPreallocated(mat, 1);
8933:   mat->factortype = MAT_FACTOR_NONE;
8934:   if (!mat->ops->setunfactored) PetscFunctionReturn(PETSC_SUCCESS);
8935:   PetscUseTypeMethod(mat, setunfactored);
8936:   PetscFunctionReturn(PETSC_SUCCESS);
8937: }

8939: /*@
8940:   MatCreateSubMatrix - Gets a single submatrix on the same number of processes
8941:   as the original matrix.

8943:   Collective

8945:   Input Parameters:
8946: + mat   - the original matrix
8947: . isrow - parallel `IS` containing the rows this process should obtain
8948: . iscol - parallel `IS` containing all columns you wish to keep. Each process should list the columns that will be in IT's "diagonal part" in the new matrix.
8949: - cll   - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

8951:   Output Parameter:
8952: . newmat - the new submatrix, of the same type as the original matrix (except potentially for `MATSEQSBAIJ`)

8954:   Level: advanced

8956:   Notes:
8957:   The submatrix will be able to be multiplied with vectors using the same layout as `iscol`.

8959:   Some matrix types place restrictions on the row and column indices, such
8960:   as that they be sorted or that they be equal to each other. For `MATBAIJ` and `MATSBAIJ` matrices the indices must include all rows/columns of a block;
8961:   for example, if the block size is 3 one cannot select the 0 and 2 rows without selecting the 1 row.
8962:   `MATSEQSBAIJ` inputs may produce a `MATSEQBAIJ` matrix when the row and column index sets do not preserve symmetry.

8964:   The index sets may not have duplicate entries.

8966:   The first time this is called you should use a `cll` of `MAT_INITIAL_MATRIX`,
8967:   the `MatCreateSubMatrix()` routine will create the newmat for you. Any additional calls
8968:   to this routine with a mat of the same nonzero structure and with a call of `MAT_REUSE_MATRIX`
8969:   will reuse the matrix generated the first time. You should call `MatDestroy()` on `newmat` when
8970:   you are finished using it.

8972:   The communicator of the newly obtained matrix is ALWAYS the same as the communicator of
8973:   the input matrix.

8975:   If `iscol` is `NULL` then all columns are obtained (not supported in Fortran).

8977:   If `isrow` and `iscol` have a nontrivial block-size, then the resulting matrix has this block-size as well. This feature
8978:   is used by `PCFIELDSPLIT` to allow easy nesting of its use.

8980:   Example usage:
8981:   Consider the following 8x8 matrix with 34 non-zero values, that is
8982:   assembled across 3 processes. Let's assume that proc0 owns 3 rows,
8983:   proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
8984:   as follows
8985: .vb
8986:             1  2  0  |  0  3  0  |  0  4
8987:     Proc0   0  5  6  |  7  0  0  |  8  0
8988:             9  0 10  | 11  0  0  | 12  0
8989:     -------------------------------------
8990:            13  0 14  | 15 16 17  |  0  0
8991:     Proc1   0 18  0  | 19 20 21  |  0  0
8992:             0  0  0  | 22 23  0  | 24  0
8993:     -------------------------------------
8994:     Proc2  25 26 27  |  0  0 28  | 29  0
8995:            30  0  0  | 31 32 33  |  0 34
8996: .ve

8998:   Suppose `isrow` = [0 1 | 4 | 6 7] and `iscol` = [1 2 | 3 4 5 | 6]. The resulting submatrix is

9000: .vb
9001:             2  0  |  0  3  0  |  0
9002:     Proc0   5  6  |  7  0  0  |  8
9003:     -------------------------------
9004:     Proc1  18  0  | 19 20 21  |  0
9005:     -------------------------------
9006:     Proc2  26 27  |  0  0 28  | 29
9007:             0  0  | 31 32 33  |  0
9008: .ve

9010: .seealso: [](ch_matrices), `Mat`, `MatCreateSubMatrices()`, `MatCreateSubMatricesMPI()`, `MatCreateSubMatrixVirtual()`, `MatSubMatrixVirtualUpdate()`
9011: @*/
9012: PetscErrorCode MatCreateSubMatrix(Mat mat, IS isrow, IS iscol, MatReuse cll, Mat *newmat)
9013: {
9014:   PetscMPIInt size;
9015:   Mat        *local;
9016:   IS          iscoltmp;
9017:   PetscBool   flg;

9019:   PetscFunctionBegin;
9023:   PetscAssertPointer(newmat, 5);
9026:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
9027:   PetscCheck(cll != MAT_IGNORE_MATRIX, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot use MAT_IGNORE_MATRIX");
9028:   PetscCheck(cll != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot use MAT_INPLACE_MATRIX");

9030:   MatCheckPreallocated(mat, 1);
9031:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));

9033:   if (!iscol || isrow == iscol) {
9034:     PetscBool   stride;
9035:     PetscMPIInt grab = 0;
9036:     PetscCall(PetscObjectTypeCompare((PetscObject)isrow, ISSTRIDE, &stride));
9037:     if (stride) {
9038:       PetscInt first, step, n, rstart, rend;
9039:       PetscCall(ISStrideGetInfo(isrow, &first, &step));
9040:       if (step == 1) {
9041:         PetscCall(MatGetOwnershipRange(mat, &rstart, &rend));
9042:         if (rstart == first) {
9043:           PetscCall(ISGetLocalSize(isrow, &n));
9044:           if (n == rend - rstart) grab = 1;
9045:         }
9046:       }
9047:     }
9048:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &grab, 1, MPI_INT, MPI_MIN, PetscObjectComm((PetscObject)mat)));
9049:     if (grab) {
9050:       PetscCall(PetscInfo(mat, "Getting entire matrix as submatrix\n"));
9051:       if (cll == MAT_INITIAL_MATRIX) {
9052:         *newmat = mat;
9053:         PetscCall(PetscObjectReference((PetscObject)mat));
9054:       }
9055:       PetscFunctionReturn(PETSC_SUCCESS);
9056:     }
9057:   }

9059:   if (!iscol) {
9060:     PetscCall(ISCreateStride(PetscObjectComm((PetscObject)mat), mat->cmap->n, mat->cmap->rstart, 1, &iscoltmp));
9061:   } else {
9062:     iscoltmp = iscol;
9063:   }

9065:   /* if original matrix is on just one process then use submatrix generated */
9066:   if (mat->ops->createsubmatrices && !mat->ops->createsubmatrix && size == 1 && cll == MAT_REUSE_MATRIX) {
9067:     PetscCall(MatCreateSubMatrices(mat, 1, &isrow, &iscoltmp, MAT_REUSE_MATRIX, &newmat));
9068:     goto setproperties;
9069:   } else if (mat->ops->createsubmatrices && !mat->ops->createsubmatrix && size == 1) {
9070:     PetscCall(MatCreateSubMatrices(mat, 1, &isrow, &iscoltmp, MAT_INITIAL_MATRIX, &local));
9071:     *newmat = *local;
9072:     PetscCall(PetscFree(local));
9073:     goto setproperties;
9074:   } else if (!mat->ops->createsubmatrix) {
9075:     /* Create a new matrix type that implements the operation using the full matrix */
9076:     PetscCall(PetscLogEventBegin(MAT_CreateSubMat, mat, 0, 0, 0));
9077:     switch (cll) {
9078:     case MAT_INITIAL_MATRIX:
9079:       PetscCall(MatCreateSubMatrixVirtual(mat, isrow, iscoltmp, newmat));
9080:       break;
9081:     case MAT_REUSE_MATRIX:
9082:       PetscCall(MatSubMatrixVirtualUpdate(*newmat, mat, isrow, iscoltmp));
9083:       break;
9084:     default:
9085:       SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "Invalid MatReuse, must be either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX");
9086:     }
9087:     PetscCall(PetscLogEventEnd(MAT_CreateSubMat, mat, 0, 0, 0));
9088:     goto setproperties;
9089:   }

9091:   PetscCall(PetscLogEventBegin(MAT_CreateSubMat, mat, 0, 0, 0));
9092:   PetscUseTypeMethod(mat, createsubmatrix, isrow, iscoltmp, cll, newmat);
9093:   PetscCall(PetscLogEventEnd(MAT_CreateSubMat, mat, 0, 0, 0));

9095: setproperties:
9096:   if ((*newmat)->symmetric == PETSC_BOOL3_UNKNOWN && (*newmat)->structurally_symmetric == PETSC_BOOL3_UNKNOWN && (*newmat)->spd == PETSC_BOOL3_UNKNOWN && (*newmat)->hermitian == PETSC_BOOL3_UNKNOWN) {
9097:     PetscCall(ISEqualUnsorted(isrow, iscoltmp, &flg));
9098:     if (flg) PetscCall(MatPropagateSymmetryOptions(mat, *newmat));
9099:   }
9100:   if (!iscol) PetscCall(ISDestroy(&iscoltmp));
9101:   if (*newmat && cll == MAT_INITIAL_MATRIX) PetscCall(PetscObjectStateIncrease((PetscObject)*newmat));
9102:   if (!iscol || isrow == iscol) PetscCall(MatSelectVariableBlockSizes(*newmat, mat, isrow));
9103:   PetscFunctionReturn(PETSC_SUCCESS);
9104: }

9106: /*@
9107:   MatPropagateSymmetryOptions - Propagates symmetry properties set on a matrix to another matrix

9109:   Not Collective

9111:   Input Parameters:
9112: + A - the matrix we wish to propagate properties from
9113: - B - the matrix we wish to propagate properties to

9115:   Level: beginner

9117:   Note:
9118:   Propagates the properties associated to `MAT_SYMMETRY_ETERNAL`, `MAT_STRUCTURALLY_SYMMETRIC`, `MAT_HERMITIAN`, `MAT_SPD`, `MAT_SYMMETRIC`, and `MAT_STRUCTURAL_SYMMETRY_ETERNAL`

9120: .seealso: [](ch_matrices), `Mat`, `MatSetOption()`, `MatIsSymmetricKnown()`, `MatIsSPDKnown()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetricKnown()`
9121: @*/
9122: PetscErrorCode MatPropagateSymmetryOptions(Mat A, Mat B)
9123: {
9124:   PetscFunctionBegin;
9127:   B->symmetry_eternal            = A->symmetry_eternal;
9128:   B->structural_symmetry_eternal = A->structural_symmetry_eternal;
9129:   B->symmetric                   = A->symmetric;
9130:   B->structurally_symmetric      = A->structurally_symmetric;
9131:   B->spd                         = A->spd;
9132:   B->hermitian                   = A->hermitian;
9133:   PetscFunctionReturn(PETSC_SUCCESS);
9134: }

9136: /*@
9137:   MatStashSetInitialSize - sets the sizes of the matrix stash, that is
9138:   used during the assembly process to store values that belong to
9139:   other processes.

9141:   Not Collective

9143:   Input Parameters:
9144: + mat   - the matrix
9145: . size  - the initial size of the stash.
9146: - bsize - the initial size of the block-stash(if used).

9148:   Options Database Key:
9149: . -matstash_initial_size (size|size0,size1,...,sizep-1) - set initial size of stash for all or each of the MPI processes, sets both block and non-block stash sizes

9151:   Level: intermediate

9153:   Notes:
9154:   The block-stash is used for values set with `MatSetValuesBlocked()` while
9155:   the stash is used for values set with `MatSetValues()`

9157:   Run with the option `-info` and look for output of the form
9158:   MatAssemblyBegin_MPIXXX:Stash has MM entries, uses nn mallocs.
9159:   to determine the appropriate value, MM, to use for size and
9160:   MatAssemblyBegin_MPIXXX:Block-Stash has BMM entries, uses nn mallocs.
9161:   to determine the value, BMM to use for bsize

9163: .seealso: [](ch_matrices), `MatAssemblyBegin()`, `MatAssemblyEnd()`, `Mat`, `MatStashGetInfo()`
9164: @*/
9165: PetscErrorCode MatStashSetInitialSize(Mat mat, PetscInt size, PetscInt bsize)
9166: {
9167:   PetscFunctionBegin;
9170:   PetscCall(MatStashSetInitialSize_Private(&mat->stash, size));
9171:   PetscCall(MatStashSetInitialSize_Private(&mat->bstash, bsize));
9172:   PetscFunctionReturn(PETSC_SUCCESS);
9173: }

9175: /*@
9176:   MatInterpolateAdd - $w = y + A x$ or $A^T x$ depending on the shape of
9177:   the matrix

9179:   Neighbor-wise Collective

9181:   Input Parameters:
9182: + A - the matrix
9183: . x - the vector to be multiplied by the interpolation operator
9184: - y - the vector to be added to the result

9186:   Output Parameter:
9187: . w - the resulting vector

9189:   Level: intermediate

9191:   Notes:
9192:   `w` may be the same vector as `y`.

9194:   This allows one to use either the restriction or interpolation (its transpose)
9195:   matrix to do the interpolation

9197: .seealso: [](ch_matrices), `Mat`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatRestrict()`, `PCMG`
9198: @*/
9199: PetscErrorCode MatInterpolateAdd(Mat A, Vec x, Vec y, Vec w)
9200: {
9201:   PetscInt M, N, Ny;

9203:   PetscFunctionBegin;
9208:   PetscCall(MatGetSize(A, &M, &N));
9209:   PetscCall(VecGetSize(y, &Ny));
9210:   if (M == Ny) PetscCall(MatMultAdd(A, x, y, w));
9211:   else PetscCall(MatMultTransposeAdd(A, x, y, w));
9212:   PetscFunctionReturn(PETSC_SUCCESS);
9213: }

9215: /*@
9216:   MatInterpolate - $y = A x$ or $A^T x$ depending on the shape of
9217:   the matrix

9219:   Neighbor-wise Collective

9221:   Input Parameters:
9222: + A - the matrix
9223: - x - the vector to be interpolated

9225:   Output Parameter:
9226: . y - the resulting vector

9228:   Level: intermediate

9230:   Note:
9231:   This allows one to use either the restriction or interpolation (its transpose)
9232:   matrix to do the interpolation

9234: .seealso: [](ch_matrices), `Mat`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatRestrict()`, `PCMG`
9235: @*/
9236: PetscErrorCode MatInterpolate(Mat A, Vec x, Vec y)
9237: {
9238:   PetscInt M, N, Ny;

9240:   PetscFunctionBegin;
9244:   PetscCall(MatGetSize(A, &M, &N));
9245:   PetscCall(VecGetSize(y, &Ny));
9246:   if (M == Ny) PetscCall(MatMult(A, x, y));
9247:   else PetscCall(MatMultTranspose(A, x, y));
9248:   PetscFunctionReturn(PETSC_SUCCESS);
9249: }

9251: /*@
9252:   MatRestrict - $y = A x$ or $A^T x$

9254:   Neighbor-wise Collective

9256:   Input Parameters:
9257: + A - the matrix
9258: - x - the vector to be restricted

9260:   Output Parameter:
9261: . y - the resulting vector

9263:   Level: intermediate

9265:   Note:
9266:   This allows one to use either the restriction or interpolation (its transpose)
9267:   matrix to do the restriction

9269: .seealso: [](ch_matrices), `Mat`, `MatMultAdd()`, `MatMultTransposeAdd()`, `MatInterpolate()`, `PCMG`
9270: @*/
9271: PetscErrorCode MatRestrict(Mat A, Vec x, Vec y)
9272: {
9273:   PetscInt M, N, Nx;

9275:   PetscFunctionBegin;
9279:   PetscCall(MatGetSize(A, &M, &N));
9280:   PetscCall(VecGetSize(x, &Nx));
9281:   if (M == Nx) PetscCall(MatMultTranspose(A, x, y));
9282:   else PetscCall(MatMult(A, x, y));
9283:   PetscFunctionReturn(PETSC_SUCCESS);
9284: }

9286: /*@
9287:   MatMatInterpolateAdd - $Y = W + A X$ or $W + A^T X$ depending on the shape of `A`

9289:   Neighbor-wise Collective

9291:   Input Parameters:
9292: + A - the matrix
9293: . x - the input dense matrix to be multiplied
9294: - w - the input dense matrix to be added to the result

9296:   Output Parameter:
9297: . y - the output dense matrix

9299:   Level: intermediate

9301:   Note:
9302:   This allows one to use either the restriction or interpolation (its transpose)
9303:   matrix to do the interpolation. `y` matrix can be reused if already created with the proper sizes,
9304:   otherwise it will be recreated. `y` must be initialized to `NULL` if not supplied.

9306: .seealso: [](ch_matrices), `Mat`, `MatInterpolateAdd()`, `MatMatInterpolate()`, `MatMatRestrict()`, `PCMG`
9307: @*/
9308: PetscErrorCode MatMatInterpolateAdd(Mat A, Mat x, Mat w, Mat *y)
9309: {
9310:   PetscInt  M, N, Mx, Nx, Mo, My = 0, Ny = 0;
9311:   PetscBool trans = PETSC_TRUE;
9312:   MatReuse  reuse = MAT_INITIAL_MATRIX;

9314:   PetscFunctionBegin;
9320:   PetscCall(MatGetSize(A, &M, &N));
9321:   PetscCall(MatGetSize(x, &Mx, &Nx));
9322:   if (N == Mx) trans = PETSC_FALSE;
9323:   else PetscCheck(M == Mx, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Size mismatch: A %" PetscInt_FMT "x%" PetscInt_FMT ", X %" PetscInt_FMT "x%" PetscInt_FMT, M, N, Mx, Nx);
9324:   Mo = trans ? N : M;
9325:   if (*y) {
9326:     PetscCall(MatGetSize(*y, &My, &Ny));
9327:     if (Mo == My && Nx == Ny) reuse = MAT_REUSE_MATRIX;
9328:     else {
9329:       PetscCheck(w || *y != w, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot reuse y and w, size mismatch: A %" PetscInt_FMT "x%" PetscInt_FMT ", X %" PetscInt_FMT "x%" PetscInt_FMT ", Y %" PetscInt_FMT "x%" PetscInt_FMT, M, N, Mx, Nx, My, Ny);
9330:       PetscCall(MatDestroy(y));
9331:     }
9332:   }

9334:   if (w && *y == w) { /* this is to minimize changes in PCMG */
9335:     PetscBool flg;

9337:     PetscCall(PetscObjectQuery((PetscObject)*y, "__MatMatIntAdd_w", (PetscObject *)&w));
9338:     if (w) {
9339:       PetscInt My, Ny, Mw, Nw;

9341:       PetscCall(PetscObjectTypeCompare((PetscObject)*y, ((PetscObject)w)->type_name, &flg));
9342:       PetscCall(MatGetSize(*y, &My, &Ny));
9343:       PetscCall(MatGetSize(w, &Mw, &Nw));
9344:       if (!flg || My != Mw || Ny != Nw) w = NULL;
9345:     }
9346:     if (!w) {
9347:       PetscCall(MatDuplicate(*y, MAT_COPY_VALUES, &w));
9348:       PetscCall(PetscObjectCompose((PetscObject)*y, "__MatMatIntAdd_w", (PetscObject)w));
9349:       PetscCall(PetscObjectDereference((PetscObject)w));
9350:     } else PetscCall(MatCopy(*y, w, UNKNOWN_NONZERO_PATTERN));
9351:   }
9352:   if (!trans) PetscCall(MatMatMult(A, x, reuse, PETSC_DETERMINE, y));
9353:   else PetscCall(MatTransposeMatMult(A, x, reuse, PETSC_DETERMINE, y));
9354:   if (w) PetscCall(MatAXPY(*y, 1.0, w, UNKNOWN_NONZERO_PATTERN));
9355:   PetscFunctionReturn(PETSC_SUCCESS);
9356: }

9358: /*@
9359:   MatMatInterpolate - $Y = A X$ or $A^T X$ depending on the shape of `A`

9361:   Neighbor-wise Collective

9363:   Input Parameters:
9364: + A - the matrix
9365: - x - the input dense matrix

9367:   Output Parameter:
9368: . y - the output dense matrix

9370:   Level: intermediate

9372:   Note:
9373:   This allows one to use either the restriction or interpolation (its transpose)
9374:   matrix to do the interpolation. `y` matrix can be reused if already created with the proper sizes,
9375:   otherwise it will be recreated. `y` must be initialized to `NULL` if not supplied.

9377: .seealso: [](ch_matrices), `Mat`, `MatInterpolate()`, `MatRestrict()`, `MatMatRestrict()`, `PCMG`
9378: @*/
9379: PetscErrorCode MatMatInterpolate(Mat A, Mat x, Mat *y)
9380: {
9381:   PetscFunctionBegin;
9382:   PetscCall(MatMatInterpolateAdd(A, x, NULL, y));
9383:   PetscFunctionReturn(PETSC_SUCCESS);
9384: }

9386: /*@
9387:   MatMatRestrict - $Y = A X$ or $A^T X$ depending on the shape of `A`

9389:   Neighbor-wise Collective

9391:   Input Parameters:
9392: + A - the matrix
9393: - x - the input dense matrix

9395:   Output Parameter:
9396: . y - the output dense matrix

9398:   Level: intermediate

9400:   Note:
9401:   This allows one to use either the restriction or interpolation (its transpose)
9402:   matrix to do the restriction. `y` matrix can be reused if already created with the proper sizes,
9403:   otherwise it will be recreated. `y` must be initialized to `NULL` if not supplied.

9405: .seealso: [](ch_matrices), `Mat`, `MatRestrict()`, `MatInterpolate()`, `MatMatInterpolate()`, `PCMG`
9406: @*/
9407: PetscErrorCode MatMatRestrict(Mat A, Mat x, Mat *y)
9408: {
9409:   PetscFunctionBegin;
9410:   PetscCall(MatMatInterpolateAdd(A, x, NULL, y));
9411:   PetscFunctionReturn(PETSC_SUCCESS);
9412: }

9414: /*@
9415:   MatGetNullSpace - retrieves the null space of a matrix that was provided with `MatSetNullSpace()`

9417:   Logically Collective

9419:   Input Parameters:
9420: + mat    - the matrix
9421: - nullsp - the null space object

9423:   Level: developer

9425: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatSetNullSpace()`, `MatNullSpace`
9426: @*/
9427: PetscErrorCode MatGetNullSpace(Mat mat, MatNullSpace *nullsp)
9428: {
9429:   PetscFunctionBegin;
9431:   PetscAssertPointer(nullsp, 2);
9432:   *nullsp = (mat->symmetric == PETSC_BOOL3_TRUE && !mat->nullsp) ? mat->transnullsp : mat->nullsp;
9433:   PetscFunctionReturn(PETSC_SUCCESS);
9434: }

9436: /*@
9437:   MatGetNullSpaces - gets the null spaces, transpose null spaces, and near null spaces from an array of matrices that were supplied with `MatSetNullSpace()`,
9438:   `MatSetTransposeNullSpace()`, and `MatSetNearNullSpace()`

9440:   Logically Collective

9442:   Input Parameters:
9443: + n   - the number of matrices
9444: - mat - the array of matrices

9446:   Output Parameters:
9447: . nullsp - an array of null spaces, `NULL` will be inserted for each matrix that does not have a null space, length 3 * `n`

9449:   Level: developer

9451:   Note:
9452:   Call `MatRestoreNullspaces()` to provide these to another array of matrices

9454: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetTransposeNullSpace()`, `MatGetTransposeNullSpace()`,
9455:           `MatNullSpaceRemove()`, `MatRestoreNullSpaces()`, `MatNullSpace`
9456: @*/
9457: PetscErrorCode MatGetNullSpaces(PetscInt n, Mat mat[], MatNullSpace *nullsp[])
9458: {
9459:   PetscFunctionBegin;
9460:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of matrices %" PetscInt_FMT " must be non-negative", n);
9461:   PetscAssertPointer(mat, 2);
9462:   PetscAssertPointer(nullsp, 3);

9464:   PetscCall(PetscCalloc1(3 * n, nullsp));
9465:   for (PetscInt i = 0; i < n; i++) {
9467:     (*nullsp)[i] = mat[i]->nullsp;
9468:     PetscCall(PetscObjectReference((PetscObject)(*nullsp)[i]));
9469:     (*nullsp)[n + i] = mat[i]->nearnullsp;
9470:     PetscCall(PetscObjectReference((PetscObject)(*nullsp)[n + i]));
9471:     (*nullsp)[2 * n + i] = mat[i]->transnullsp;
9472:     PetscCall(PetscObjectReference((PetscObject)(*nullsp)[2 * n + i]));
9473:   }
9474:   PetscFunctionReturn(PETSC_SUCCESS);
9475: }

9477: /*@
9478:   MatRestoreNullSpaces - sets the null spaces, transpose null spaces, and near null spaces obtained with `MatGetNullSpaces()` for an array of matrices

9480:   Logically Collective

9482:   Input Parameters:
9483: + n      - the number of matrices
9484: . mat    - the array of matrices
9485: - nullsp - an array of null spaces, of length  3 * `n`

9487:   Level: developer

9489:   Notes:
9490:   Call `MatGetNullSpaces()` to create `nullsp`.

9492:   Frees `nullsp`.

9494:   Developer Note:
9495:   The name of this function is confusing. Traditionally in PETSc, a restore operation undoes something that was previously done on an object (or objects) with a get operation.
9496:   This restore routine does something to a new set of objects using the results of a get operation on a previous set of objects. Perhaps this routine
9497:   should have simply been called `MatSetNullSpaces()`

9499: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetTransposeNullSpace()`, `MatGetTransposeNullSpace()`,
9500:           `MatNullSpaceRemove()`, `MatGetNullSpaces()`, `MatNullSpace`
9501: @*/
9502: PetscErrorCode MatRestoreNullSpaces(PetscInt n, Mat mat[], MatNullSpace *nullsp[])
9503: {
9504:   PetscFunctionBegin;
9505:   PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Number of matrices %" PetscInt_FMT " must be non-negative", n);
9506:   PetscAssertPointer(mat, 2);
9507:   PetscAssertPointer(nullsp, 3);
9508:   PetscAssertPointer(*nullsp, 3);

9510:   for (PetscInt i = 0; i < n; i++) {
9512:     PetscCall(MatSetNullSpace(mat[i], (*nullsp)[i]));
9513:     PetscCall(PetscObjectDereference((PetscObject)(*nullsp)[i]));
9514:     PetscCall(MatSetNearNullSpace(mat[i], (*nullsp)[n + i]));
9515:     PetscCall(PetscObjectDereference((PetscObject)(*nullsp)[n + i]));
9516:     PetscCall(MatSetTransposeNullSpace(mat[i], (*nullsp)[2 * n + i]));
9517:     PetscCall(PetscObjectDereference((PetscObject)(*nullsp)[2 * n + i]));
9518:   }
9519:   PetscCall(PetscFree(*nullsp));
9520:   PetscFunctionReturn(PETSC_SUCCESS);
9521: }

9523: /*@
9524:   MatSetNullSpace - attaches a null space to a matrix.

9526:   Logically Collective

9528:   Input Parameters:
9529: + mat    - the matrix
9530: - nullsp - the null space object

9532:   Level: advanced

9534:   Notes:
9535:   This null space is used by the `KSP` linear solvers to solve singular systems.

9537:   Overwrites any previous null space that may have been attached. You can remove the null space from the matrix object by calling this routine with an nullsp of `NULL`

9539:   For inconsistent singular systems (linear systems where the right-hand side is not in the range of the operator) the `KSP` residuals will not converge
9540:   to zero but the linear system will still be solved in a least squares sense.

9542:   The fundamental theorem of linear algebra (Gilbert Strang, Introduction to Applied Mathematics, page 72) states that
9543:   the domain of a matrix $A$ (from $R^n$ to $R^m$ ($m$ rows, $n$ columns) $R^n$ = the direct sum of the null space of $A$, $n(A)$, plus the range of $A^T$, $R(A^T)$.
9544:   Similarly $R^m$ = direct sum $n(A^T) + R(A)$. Hence the linear system $A x = b$ has a solution only if $b$ in $R(A)$ (or correspondingly $b$ is orthogonal to
9545:   $n(A^T))$ and if $x$ is a solution then $x + \alpha n(A)$ is a solution for any $\alpha$. The minimum norm solution is orthogonal to $n(A)$. For problems without a solution
9546:   the solution that minimizes the norm of the residual (the least squares solution) can be obtained by solving $A x = \hat{b}$ where $\hat{b}$ is $b$ orthogonalized to the $n(A^T)$.
9547:   This  $\hat{b}$ can be obtained by calling `MatNullSpaceRemove()` with the null space of the transpose of the matrix.

9549:   If the matrix is known to be symmetric because it is an `MATSBAIJ` matrix or one has called
9550:   `MatSetOption`(mat,`MAT_SYMMETRIC` or possibly `MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`); this
9551:   routine also automatically calls `MatSetTransposeNullSpace()`.

9553:   The user should call `MatNullSpaceDestroy()`.

9555: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetTransposeNullSpace()`, `MatGetTransposeNullSpace()`, `MatNullSpaceRemove()`,
9556:           `KSPSetPCSide()`, `MatNullSpace`
9557: @*/
9558: PetscErrorCode MatSetNullSpace(Mat mat, MatNullSpace nullsp)
9559: {
9560:   PetscFunctionBegin;
9563:   PetscCall(PetscObjectReference((PetscObject)nullsp));
9564:   PetscCall(MatNullSpaceDestroy(&mat->nullsp));
9565:   mat->nullsp = nullsp;
9566:   if (mat->symmetric == PETSC_BOOL3_TRUE) PetscCall(MatSetTransposeNullSpace(mat, nullsp));
9567:   PetscFunctionReturn(PETSC_SUCCESS);
9568: }

9570: /*@
9571:   MatGetTransposeNullSpace - retrieves the null space of the transpose of a matrix that was set with `MatSetTransposeNullSpace()`

9573:   Logically Collective

9575:   Input Parameters:
9576: + mat    - the matrix
9577: - nullsp - the null space object

9579:   Level: developer

9581: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatSetTransposeNullSpace()`, `MatSetNullSpace()`, `MatGetNullSpace()`
9582: @*/
9583: PetscErrorCode MatGetTransposeNullSpace(Mat mat, MatNullSpace *nullsp)
9584: {
9585:   PetscFunctionBegin;
9588:   PetscAssertPointer(nullsp, 2);
9589:   *nullsp = (mat->symmetric == PETSC_BOOL3_TRUE && !mat->transnullsp) ? mat->nullsp : mat->transnullsp;
9590:   PetscFunctionReturn(PETSC_SUCCESS);
9591: }

9593: /*@
9594:   MatSetTransposeNullSpace - attaches the null space of a transpose of a matrix to the matrix

9596:   Logically Collective

9598:   Input Parameters:
9599: + mat    - the matrix
9600: - nullsp - the null space object

9602:   Level: advanced

9604:   Notes:
9605:   This allows solving singular linear systems defined by the transpose of the matrix using `KSP` solvers with left preconditioning.

9607:   See `MatSetNullSpace()`

9609: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatSetNullSpace()`, `MatGetTransposeNullSpace()`, `MatNullSpaceRemove()`, `KSPSetPCSide()`
9610: @*/
9611: PetscErrorCode MatSetTransposeNullSpace(Mat mat, MatNullSpace nullsp)
9612: {
9613:   PetscFunctionBegin;
9616:   PetscCall(PetscObjectReference((PetscObject)nullsp));
9617:   PetscCall(MatNullSpaceDestroy(&mat->transnullsp));
9618:   mat->transnullsp = nullsp;
9619:   PetscFunctionReturn(PETSC_SUCCESS);
9620: }

9622: /*@
9623:   MatSetNearNullSpace - attaches a null space to a matrix, which is often the null space (rigid body modes) of the operator without boundary conditions
9624:   This null space will be used to provide near null space vectors to a multigrid preconditioner built from this matrix.

9626:   Logically Collective

9628:   Input Parameters:
9629: + mat    - the matrix
9630: - nullsp - the null space object

9632:   Level: advanced

9634:   Notes:
9635:   Overwrites any previous near null space that may have been attached

9637:   You can remove the null space by calling this routine with an `nullsp` of `NULL`

9639: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatCreate()`, `MatNullSpaceCreate()`, `MatSetNullSpace()`, `MatNullSpaceCreateRigidBody()`, `MatGetNearNullSpace()`
9640: @*/
9641: PetscErrorCode MatSetNearNullSpace(Mat mat, MatNullSpace nullsp)
9642: {
9643:   PetscFunctionBegin;
9647:   MatCheckPreallocated(mat, 1);
9648:   PetscCall(PetscObjectReference((PetscObject)nullsp));
9649:   PetscCall(MatNullSpaceDestroy(&mat->nearnullsp));
9650:   mat->nearnullsp = nullsp;
9651:   PetscFunctionReturn(PETSC_SUCCESS);
9652: }

9654: /*@
9655:   MatGetNearNullSpace - Get null space from a matrix that was attached with `MatSetNearNullSpace()`

9657:   Not Collective

9659:   Input Parameter:
9660: . mat - the matrix

9662:   Output Parameter:
9663: . nullsp - the null space object, `NULL` if not set

9665:   Level: advanced

9667: .seealso: [](ch_matrices), `Mat`, `MatNullSpace`, `MatSetNearNullSpace()`, `MatGetNullSpace()`, `MatNullSpaceCreate()`
9668: @*/
9669: PetscErrorCode MatGetNearNullSpace(Mat mat, MatNullSpace *nullsp)
9670: {
9671:   PetscFunctionBegin;
9674:   PetscAssertPointer(nullsp, 2);
9675:   MatCheckPreallocated(mat, 1);
9676:   *nullsp = mat->nearnullsp;
9677:   PetscFunctionReturn(PETSC_SUCCESS);
9678: }

9680: /*@
9681:   MatICCFactor - Performs in-place incomplete Cholesky factorization of matrix.

9683:   Collective

9685:   Input Parameters:
9686: + mat  - the matrix
9687: . row  - row/column permutation
9688: - info - information on desired factorization process

9690:   Level: developer

9692:   Notes:
9693:   Probably really in-place only when level of fill is zero, otherwise allocates
9694:   new space to store factored matrix and deletes previous memory.

9696:   Most users should employ the `KSP` interface for linear solvers
9697:   instead of working directly with matrix algebra routines such as this.
9698:   See, e.g., `KSPCreate()`.

9700:   Fortran Note:
9701:   A valid (non-null) `info` argument must be provided

9703: .seealso: [](ch_matrices), `Mat`, `MatFactorInfo`, `MatGetFactor()`, `MatICCFactorSymbolic()`, `MatLUFactorNumeric()`, `MatCholeskyFactor()`
9704: @*/
9705: PetscErrorCode MatICCFactor(Mat mat, IS row, const MatFactorInfo *info)
9706: {
9707:   PetscFunctionBegin;
9711:   PetscAssertPointer(info, 3);
9712:   PetscCheck(mat->rmap->N == mat->cmap->N, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONG, "matrix must be square");
9713:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
9714:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
9715:   MatCheckPreallocated(mat, 1);
9716:   PetscUseTypeMethod(mat, iccfactor, row, info);
9717:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
9718:   PetscFunctionReturn(PETSC_SUCCESS);
9719: }

9721: /*@
9722:   MatDiagonalScaleLocal - Scales columns of a matrix given the scaling values including the
9723:   ghosted ones.

9725:   Not Collective

9727:   Input Parameters:
9728: + mat  - the matrix
9729: - diag - the diagonal values, including ghost ones

9731:   Level: developer

9733:   Notes:
9734:   Works only for `MATMPIAIJ` and `MATMPIBAIJ` matrices

9736:   `diag` is a sequential vector that has a length which is the same as the local (ghosted) length of the vector associated with
9737:   the matrix's `ISLocalToGlobalMapping` set with `MatSetLocalToGlobalMapping()`.

9739:   This allows one to avoid during communication to perform the scaling that must be done with `MatDiagonalScale()`.

9741: .seealso: [](ch_matrices), `Mat`, `MatDiagonalScale()`, `MatSetLocalToGlobalMapping()`, `ISLocalToGlobalMapping`
9742: @*/
9743: PetscErrorCode MatDiagonalScaleLocal(Mat mat, Vec diag)
9744: {
9745:   PetscMPIInt size;

9747:   PetscFunctionBegin;

9752:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Matrix must be already assembled");
9753:   PetscCall(PetscLogEventBegin(MAT_Scale, mat, 0, 0, 0));
9754:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));
9755:   if (size == 1) {
9756:     PetscInt n, m;
9757:     PetscCall(VecGetSize(diag, &n));
9758:     PetscCall(MatGetSize(mat, NULL, &m));
9759:     PetscCheck(m == n, PETSC_COMM_SELF, PETSC_ERR_SUP, "Only supported for sequential matrices when no ghost points/periodic conditions");
9760:     PetscCall(MatDiagonalScale(mat, NULL, diag));
9761:   } else PetscUseMethod(mat, "MatDiagonalScaleLocal_C", (Mat, Vec), (mat, diag));
9762:   PetscCall(PetscLogEventEnd(MAT_Scale, mat, 0, 0, 0));
9763:   PetscCall(PetscObjectStateIncrease((PetscObject)mat));
9764:   PetscFunctionReturn(PETSC_SUCCESS);
9765: }

9767: /*@
9768:   MatGetInertia - Gets the inertia from a factored matrix

9770:   Collective

9772:   Input Parameter:
9773: . mat - the matrix

9775:   Output Parameters:
9776: + nneg  - number of negative eigenvalues
9777: . nzero - number of zero eigenvalues
9778: - npos  - number of positive eigenvalues

9780:   Level: advanced

9782:   Note:
9783:   Matrix must have been factored by `MatCholeskyFactor()`

9785: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatCholeskyFactor()`
9786: @*/
9787: PetscErrorCode MatGetInertia(Mat mat, PetscInt *nneg, PetscInt *nzero, PetscInt *npos)
9788: {
9789:   PetscFunctionBegin;
9792:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Unfactored matrix");
9793:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Numeric factor mat is not assembled");
9794:   PetscUseTypeMethod(mat, getinertia, nneg, nzero, npos);
9795:   PetscFunctionReturn(PETSC_SUCCESS);
9796: }

9798: /*@
9799:   MatSolves - Solves $A x = b$, given a factored matrix, for a collection of vectors

9801:   Neighbor-wise Collective

9803:   Input Parameters:
9804: + mat - the factored matrix obtained with `MatGetFactor()`
9805: - b   - the right-hand-side vectors

9807:   Output Parameter:
9808: . x - the result vectors

9810:   Level: developer

9812:   Note:
9813:   The vectors `b` and `x` cannot be the same. I.e., one cannot
9814:   call `MatSolves`(A,x,x).

9816: .seealso: [](ch_matrices), `Mat`, `Vecs`, `MatGetFactor()`, `MatSolveAdd()`, `MatSolveTranspose()`, `MatSolveTransposeAdd()`, `MatSolve()`
9817: @*/
9818: PetscErrorCode MatSolves(Mat mat, Vecs b, Vecs x)
9819: {
9820:   PetscFunctionBegin;
9823:   PetscCheck(x != b, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_IDN, "x and b must be different vectors");
9824:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Unfactored matrix");
9825:   if (!mat->rmap->N && !mat->cmap->N) PetscFunctionReturn(PETSC_SUCCESS);

9827:   MatCheckPreallocated(mat, 1);
9828:   PetscCall(PetscLogEventBegin(MAT_Solves, mat, 0, 0, 0));
9829:   PetscUseTypeMethod(mat, solves, b, x);
9830:   PetscCall(PetscLogEventEnd(MAT_Solves, mat, 0, 0, 0));
9831:   PetscFunctionReturn(PETSC_SUCCESS);
9832: }

9834: /*@
9835:   MatIsSymmetric - Test whether a matrix is symmetric

9837:   Collective

9839:   Input Parameters:
9840: + A   - the matrix to test
9841: - tol - difference between value and its transpose less than this amount counts as equal (use 0.0 for exact transpose)

9843:   Output Parameter:
9844: . flg - the result

9846:   Level: intermediate

9848:   Notes:
9849:   For real numbers `MatIsSymmetric()` and `MatIsHermitian()` return identical results

9851:   If the matrix does not yet know if it is symmetric or not this can be an expensive operation, also available `MatIsSymmetricKnown()`

9853:   One can declare that a matrix is symmetric with `MatSetOption`(mat,`MAT_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain symmetric
9854:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`). If these properties
9855:   have been set then `MatIsSymmetric()` does not need to perform any computations and returns immediately with the result.

9857: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetricKnown()`,
9858:           `MAT_SYMMETRIC`, `MAT_SYMMETRY_ETERNAL`
9859: @*/
9860: PetscErrorCode MatIsSymmetric(Mat A, PetscReal tol, PetscBool *flg)
9861: {
9862:   PetscFunctionBegin;
9864:   PetscAssertPointer(flg, 3);
9865:   if (A->symmetric != PETSC_BOOL3_UNKNOWN && !tol) *flg = PetscBool3ToBool(A->symmetric);
9866:   else {
9867:     if (A->ops->issymmetric) PetscUseTypeMethod(A, issymmetric, tol, flg);
9868:     else PetscCall(MatIsTranspose(A, A, tol, flg));
9869:     if (!tol) PetscCall(MatSetOption(A, MAT_SYMMETRIC, *flg));
9870:   }
9871:   PetscFunctionReturn(PETSC_SUCCESS);
9872: }

9874: /*@
9875:   MatIsHermitian - Test whether a matrix is Hermitian

9877:   Collective

9879:   Input Parameters:
9880: + A   - the matrix to test
9881: - tol - difference between value and its transpose less than this amount counts as equal (use 0.0 for exact Hermitian)

9883:   Output Parameter:
9884: . flg - the result

9886:   Level: intermediate

9888:   Notes:
9889:   For real numbers `MatIsSymmetric()` and `MatIsHermitian()` return identical results

9891:   If the matrix does not yet know if it is Hermitian or not this can be an expensive operation, also available `MatIsHermitianKnown()`

9893:   One can declare that a matrix is Hermitian with `MatSetOption`(mat,`MAT_HERMITIAN`,`PETSC_TRUE`) and if it is known to remain Hermitian
9894:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`). If these properties
9895:   have been set then `MatIsHermitian()` does not need to perform any computations and returns immediately with the result.

9897: .seealso: [](ch_matrices), `Mat`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitianKnown()`, `MatIsStructurallySymmetric()`, `MatSetOption()`,
9898:           `MatIsSymmetricKnown()`, `MatIsSymmetric()`, `MAT_HERMITIAN`, `MAT_SYMMETRY_ETERNAL`
9899: @*/
9900: PetscErrorCode MatIsHermitian(Mat A, PetscReal tol, PetscBool *flg)
9901: {
9902:   PetscFunctionBegin;
9904:   PetscAssertPointer(flg, 3);
9905:   if (A->hermitian != PETSC_BOOL3_UNKNOWN && !tol) *flg = PetscBool3ToBool(A->hermitian);
9906:   else {
9907:     if (A->ops->ishermitian) PetscUseTypeMethod(A, ishermitian, tol, flg);
9908:     else PetscCall(MatIsHermitianTranspose(A, A, tol, flg));
9909:     if (!tol) PetscCall(MatSetOption(A, MAT_HERMITIAN, *flg));
9910:   }
9911:   PetscFunctionReturn(PETSC_SUCCESS);
9912: }

9914: /*@
9915:   MatIsSymmetricKnown - Checks if a matrix knows if it is symmetric or not and its symmetric state

9917:   Not Collective

9919:   Input Parameter:
9920: . A - the matrix to check

9922:   Output Parameters:
9923: + set - `PETSC_TRUE` if the matrix knows its symmetry state (this tells you if the next flag is valid)
9924: - flg - the result (only valid if set is `PETSC_TRUE`)

9926:   Level: advanced

9928:   Notes:
9929:   Does not check the matrix values directly, so this may return unknown (set = `PETSC_FALSE`). Use `MatIsSymmetric()`
9930:   if you want it explicitly checked

9932:   One can declare that a matrix is symmetric with `MatSetOption`(mat,`MAT_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain symmetric
9933:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

9935: .seealso: [](ch_matrices), `Mat`, `MAT_SYMMETRY_ETERNAL`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitianKnown()`
9936: @*/
9937: PetscErrorCode MatIsSymmetricKnown(Mat A, PetscBool *set, PetscBool *flg)
9938: {
9939:   PetscFunctionBegin;
9941:   PetscAssertPointer(set, 2);
9942:   PetscAssertPointer(flg, 3);
9943:   if (A->symmetric != PETSC_BOOL3_UNKNOWN) {
9944:     *set = PETSC_TRUE;
9945:     *flg = PetscBool3ToBool(A->symmetric);
9946:   } else *set = PETSC_FALSE;
9947:   PetscFunctionReturn(PETSC_SUCCESS);
9948: }

9950: /*@
9951:   MatIsSPDKnown - Checks if a matrix knows if it is symmetric positive definite or not and its symmetric positive definite state

9953:   Not Collective

9955:   Input Parameter:
9956: . A - the matrix to check

9958:   Output Parameters:
9959: + set - `PETSC_TRUE` if the matrix knows its symmetric positive definite state (this tells you if the next flag is valid)
9960: - flg - the result (only valid if set is `PETSC_TRUE`)

9962:   Level: advanced

9964:   Notes:
9965:   Does not check the matrix values directly, so this may return unknown (set = `PETSC_FALSE`).

9967:   One can declare that a matrix is SPD with `MatSetOption`(mat,`MAT_SPD`,`PETSC_TRUE`) and if it is known to remain SPD
9968:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SPD_ETERNAL`,`PETSC_TRUE`)

9970: .seealso: [](ch_matrices), `Mat`, `MAT_SPD_ETERNAL`, `MAT_SPD`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitianKnown()`
9971: @*/
9972: PetscErrorCode MatIsSPDKnown(Mat A, PetscBool *set, PetscBool *flg)
9973: {
9974:   PetscFunctionBegin;
9976:   PetscAssertPointer(set, 2);
9977:   PetscAssertPointer(flg, 3);
9978:   if (A->spd != PETSC_BOOL3_UNKNOWN) {
9979:     *set = PETSC_TRUE;
9980:     *flg = PetscBool3ToBool(A->spd);
9981:   } else *set = PETSC_FALSE;
9982:   PetscFunctionReturn(PETSC_SUCCESS);
9983: }

9985: /*@
9986:   MatIsHermitianKnown - Checks if a matrix knows if it is Hermitian or not and its Hermitian state

9988:   Not Collective

9990:   Input Parameter:
9991: . A - the matrix to check

9993:   Output Parameters:
9994: + set - `PETSC_TRUE` if the matrix knows its Hermitian state (this tells you if the next flag is valid)
9995: - flg - the result (only valid if set is `PETSC_TRUE`)

9997:   Level: advanced

9999:   Notes:
10000:   Does not check the matrix values directly, so this may return unknown (set = `PETSC_FALSE`). Use `MatIsHermitian()`
10001:   if you want it explicitly checked

10003:   One can declare that a matrix is Hermitian with `MatSetOption`(mat,`MAT_HERMITIAN`,`PETSC_TRUE`) and if it is known to remain Hermitian
10004:   after changes to the matrices values one can call `MatSetOption`(mat,`MAT_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

10006: .seealso: [](ch_matrices), `Mat`, `MAT_SYMMETRY_ETERNAL`, `MAT_HERMITIAN`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`
10007: @*/
10008: PetscErrorCode MatIsHermitianKnown(Mat A, PetscBool *set, PetscBool *flg)
10009: {
10010:   PetscFunctionBegin;
10012:   PetscAssertPointer(set, 2);
10013:   PetscAssertPointer(flg, 3);
10014:   if (A->hermitian != PETSC_BOOL3_UNKNOWN) {
10015:     *set = PETSC_TRUE;
10016:     *flg = PetscBool3ToBool(A->hermitian);
10017:   } else *set = PETSC_FALSE;
10018:   PetscFunctionReturn(PETSC_SUCCESS);
10019: }

10021: /*@
10022:   MatIsStructurallySymmetric - Test whether a matrix is structurally symmetric

10024:   Collective

10026:   Input Parameter:
10027: . A - the matrix to test

10029:   Output Parameter:
10030: . flg - the result

10032:   Level: intermediate

10034:   Notes:
10035:   If the matrix does yet know it is structurally symmetric this can be an expensive operation, also available `MatIsStructurallySymmetricKnown()`

10037:   One can declare that a matrix is structurally symmetric with `MatSetOption`(mat,`MAT_STRUCTURALLY_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain structurally
10038:   symmetric after changes to the matrices values one can call `MatSetOption`(mat,`MAT_STRUCTURAL_SYMMETRY_ETERNAL`,`PETSC_TRUE`). If these properties
10039:   have been set then `MatIsStructurallySymmetric()` does not need to perform any computations and returns immediately with the result.

10041: .seealso: [](ch_matrices), `Mat`, `MAT_STRUCTURALLY_SYMMETRIC`, `MAT_STRUCTURAL_SYMMETRY_ETERNAL`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsSymmetric()`, `MatSetOption()`, `MatIsStructurallySymmetricKnown()`
10042: @*/
10043: PetscErrorCode MatIsStructurallySymmetric(Mat A, PetscBool *flg)
10044: {
10045:   PetscFunctionBegin;
10047:   PetscAssertPointer(flg, 2);
10048:   if (A->structurally_symmetric != PETSC_BOOL3_UNKNOWN) *flg = PetscBool3ToBool(A->structurally_symmetric);
10049:   else {
10050:     PetscUseTypeMethod(A, isstructurallysymmetric, flg);
10051:     PetscCall(MatSetOption(A, MAT_STRUCTURALLY_SYMMETRIC, *flg));
10052:   }
10053:   PetscFunctionReturn(PETSC_SUCCESS);
10054: }

10056: /*@
10057:   MatIsStructurallySymmetricKnown - Checks if a matrix knows if it is structurally symmetric or not and its structurally symmetric state

10059:   Not Collective

10061:   Input Parameter:
10062: . A - the matrix to check

10064:   Output Parameters:
10065: + set - `PETSC_TRUE` if the matrix knows its structurally symmetric state (this tells you if the next flag is valid)
10066: - flg - the result (only valid if set is `PETSC_TRUE`)

10068:   Level: advanced

10070:   Notes:
10071:   One can declare that a matrix is structurally symmetric with `MatSetOption`(mat,`MAT_STRUCTURALLY_SYMMETRIC`,`PETSC_TRUE`) and if it is known to remain structurally
10072:   symmetric after changes to the matrices values one can call `MatSetOption`(mat,`MAT_STRUCTURAL_SYMMETRY_ETERNAL`,`PETSC_TRUE`)

10074:   Use `MatIsStructurallySymmetric()` to explicitly check if a matrix is structurally symmetric (this is an expensive operation)

10076: .seealso: [](ch_matrices), `Mat`, `MAT_STRUCTURALLY_SYMMETRIC`, `MatTranspose()`, `MatIsTranspose()`, `MatIsHermitian()`, `MatIsStructurallySymmetric()`, `MatSetOption()`, `MatIsSymmetric()`, `MatIsHermitianKnown()`
10077: @*/
10078: PetscErrorCode MatIsStructurallySymmetricKnown(Mat A, PetscBool *set, PetscBool *flg)
10079: {
10080:   PetscFunctionBegin;
10082:   PetscAssertPointer(set, 2);
10083:   PetscAssertPointer(flg, 3);
10084:   if (A->structurally_symmetric != PETSC_BOOL3_UNKNOWN) {
10085:     *set = PETSC_TRUE;
10086:     *flg = PetscBool3ToBool(A->structurally_symmetric);
10087:   } else *set = PETSC_FALSE;
10088:   PetscFunctionReturn(PETSC_SUCCESS);
10089: }

10091: /*@
10092:   MatStashGetInfo - Gets how many values are currently in the matrix stash, i.e. need
10093:   to be communicated to other processes during the `MatAssemblyBegin()`/`MatAssemblyEnd()` process

10095:   Not Collective

10097:   Input Parameter:
10098: . mat - the matrix

10100:   Output Parameters:
10101: + nstash    - the size of the stash
10102: . reallocs  - the number of additional mallocs incurred.
10103: . bnstash   - the size of the block stash
10104: - breallocs - the number of additional mallocs incurred.in the block stash

10106:   Level: advanced

10108: .seealso: [](ch_matrices), `MatAssemblyBegin()`, `MatAssemblyEnd()`, `Mat`, `MatStashSetInitialSize()`
10109: @*/
10110: PetscErrorCode MatStashGetInfo(Mat mat, PetscInt *nstash, PetscInt *reallocs, PetscInt *bnstash, PetscInt *breallocs)
10111: {
10112:   PetscFunctionBegin;
10113:   PetscCall(MatStashGetInfo_Private(&mat->stash, nstash, reallocs));
10114:   PetscCall(MatStashGetInfo_Private(&mat->bstash, bnstash, breallocs));
10115:   PetscFunctionReturn(PETSC_SUCCESS);
10116: }

10118: /*@
10119:   MatCreateVecs - Get vector(s) compatible with the matrix, i.e. with the same
10120:   parallel layout, `PetscLayout` for rows and columns

10122:   Collective

10124:   Input Parameter:
10125: . mat - the matrix

10127:   Output Parameters:
10128: + right - (optional) vector that the matrix can be multiplied against
10129: - left  - (optional) vector that the matrix vector product can be stored in

10131:   Options Database Key:
10132: . -mat_vec_type type - set the `VecType` of the created vectors during `MatSetFromOptions()`

10134:   Level: advanced

10136:   Notes:
10137:   The blocksize of the returned vectors is determined by the row and column block sizes set with `MatSetBlockSizes()` or the single blocksize (same for both) set by `MatSetBlockSize()`.

10139:   The `VecType` of the created vectors is determined by the `MatType` of `mat`. This can be overridden by using `MatSetVecType()` or the option `-mat_vec_type`.

10141:   These are new vectors which are not owned by the `mat`, they should be destroyed with `VecDestroy()` when no longer needed.

10143:   PETSc `Vec` always have all zero entries when created with `MatCreateVecs()` until routines such as `VecSet()` or `VecSetValues()`
10144:   are used to change the values. There is no reason to call `VecZeroEntries()` after creation.

10146: .seealso: [](ch_matrices), `Mat`, `Vec`, `VecCreate()`, `VecDestroy()`, `DMCreateGlobalVector()`, `MatSetVecType()`
10147: @*/
10148: PetscErrorCode MatCreateVecs(Mat mat, Vec *right, Vec *left)
10149: {
10150:   PetscFunctionBegin;
10153:   if (mat->ops->getvecs) {
10154:     PetscUseTypeMethod(mat, getvecs, right, left);
10155:   } else {
10156:     if (right) {
10157:       PetscCheck(mat->cmap->n >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "PetscLayout for columns not yet setup");
10158:       PetscCall(VecCreateWithLayout_Private(mat->cmap, right));
10159:       PetscCall(VecSetType(*right, mat->defaultvectype));
10160: #if PetscDefined(HAVE_VIENNACL) || PetscDefined(HAVE_CUDA) || PetscDefined(HAVE_HIP)
10161:       if (mat->boundtocpu && mat->bindingpropagates) {
10162:         PetscCall(VecSetBindingPropagates(*right, PETSC_TRUE));
10163:         PetscCall(VecBindToCPU(*right, PETSC_TRUE));
10164:       }
10165: #endif
10166:     }
10167:     if (left) {
10168:       PetscCheck(mat->rmap->n >= 0, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "PetscLayout for rows not yet setup");
10169:       PetscCall(VecCreateWithLayout_Private(mat->rmap, left));
10170:       PetscCall(VecSetType(*left, mat->defaultvectype));
10171: #if PetscDefined(HAVE_VIENNACL) || PetscDefined(HAVE_CUDA) || PetscDefined(HAVE_HIP)
10172:       if (mat->boundtocpu && mat->bindingpropagates) {
10173:         PetscCall(VecSetBindingPropagates(*left, PETSC_TRUE));
10174:         PetscCall(VecBindToCPU(*left, PETSC_TRUE));
10175:       }
10176: #endif
10177:     }
10178:   }
10179:   PetscFunctionReturn(PETSC_SUCCESS);
10180: }

10182: /*@
10183:   MatFactorInfoInitialize - Initializes a `MatFactorInfo` data structure
10184:   with default values.

10186:   Not Collective

10188:   Input Parameter:
10189: . info - the `MatFactorInfo` data structure

10191:   Level: developer

10193:   Notes:
10194:   The solvers are generally used through the `KSP` and `PC` objects, for example
10195:   `PCLU`, `PCILU`, `PCCHOLESKY`, `PCICC`

10197:   Once the data structure is initialized one may change certain entries as desired for the particular factorization to be performed

10199: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorInfo`
10200: @*/
10201: PetscErrorCode MatFactorInfoInitialize(MatFactorInfo *info)
10202: {
10203:   PetscFunctionBegin;
10204:   PetscCall(PetscMemzero(info, sizeof(MatFactorInfo)));
10205:   PetscFunctionReturn(PETSC_SUCCESS);
10206: }

10208: /*@
10209:   MatFactorSetSchurIS - Set indices corresponding to the Schur complement you wish to have computed

10211:   Collective

10213:   Input Parameters:
10214: + mat - the factored matrix
10215: - is  - the index set defining the Schur indices (0-based)

10217:   Level: advanced

10219:   Notes:
10220:   Call `MatFactorSolveSchurComplement()` or `MatFactorSolveSchurComplementTranspose()` after this call to solve a Schur complement system.

10222:   You can call `MatFactorGetSchurComplement()` or `MatFactorCreateSchurComplement()` after this call.

10224:   This functionality is only supported for `MATSOLVERMUMPS` and `MATSOLVERMKL_PARDISO`

10226: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorGetSchurComplement()`, `MatFactorRestoreSchurComplement()`, `MatFactorCreateSchurComplement()`, `MatFactorSolveSchurComplement()`,
10227:           `MatFactorSolveSchurComplementTranspose()`, `MATSOLVERMUMPS`, `MATSOLVERMKL_PARDISO`
10228: @*/
10229: PetscErrorCode MatFactorSetSchurIS(Mat mat, IS is)
10230: {
10231:   PetscErrorCode (*f)(Mat, IS);

10233:   PetscFunctionBegin;
10238:   PetscCheckSameComm(mat, 1, is, 2);
10239:   PetscCheck(mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Only for factored matrix");
10240:   PetscCall(PetscObjectQueryFunction((PetscObject)mat, "MatFactorSetSchurIS_C", &f));
10241:   PetscCheck(f, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "The selected MatSolverType does not support Schur complement computation. You should use MATSOLVERMUMPS or MATSOLVERMKL_PARDISO");
10242:   PetscCall((*f)(mat, is));
10243:   PetscCheck(mat->schur, PetscObjectComm((PetscObject)mat), PETSC_ERR_PLIB, "Schur complement has not been created");
10244:   PetscFunctionReturn(PETSC_SUCCESS);
10245: }

10247: /*@
10248:   MatFactorCreateSchurComplement - Create a Schur complement matrix object using Schur data computed during the factorization step

10250:   Logically Collective

10252:   Input Parameters:
10253: + F      - the factored matrix obtained by calling `MatGetFactor()`
10254: . S      - location where to return the Schur complement, can be `NULL`
10255: - status - the status of the Schur complement matrix, can be `NULL`

10257:   Level: advanced

10259:   Notes:
10260:   You must call `MatFactorSetSchurIS()` before calling this routine.

10262:   This functionality is only supported for `MATSOLVERMUMPS` and `MATSOLVERMKL_PARDISO`

10264:   The routine provides a copy of the Schur matrix stored within the solver data structures.
10265:   The caller must destroy the object when it is no longer needed.
10266:   If `MatFactorInvertSchurComplement()` has been called, the routine gets back the inverse.

10268:   Use `MatFactorGetSchurComplement()` to get access to the Schur complement matrix inside the factored matrix instead of making a copy of it (which this function does)

10270:   See `MatCreateSchurComplement()` or `MatGetSchurComplement()` for ways to create virtual or approximate Schur complements.

10272:   Developer Note:
10273:   The reason this routine exists is because the representation of the Schur complement within the factor matrix may be different than a standard PETSc
10274:   matrix representation and we normally do not want to use the time or memory to make a copy as a regular PETSc matrix.

10276: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorGetSchurComplement()`, `MatFactorSchurStatus`, `MATSOLVERMUMPS`, `MATSOLVERMKL_PARDISO`
10277: @*/
10278: PetscErrorCode MatFactorCreateSchurComplement(Mat F, Mat *S, MatFactorSchurStatus *status)
10279: {
10280:   PetscFunctionBegin;
10282:   if (S) PetscAssertPointer(S, 2);
10283:   if (status) PetscAssertPointer(status, 3);
10284:   if (S) {
10285:     PetscErrorCode (*f)(Mat, Mat *);

10287:     PetscCall(PetscObjectQueryFunction((PetscObject)F, "MatFactorCreateSchurComplement_C", &f));
10288:     if (f) PetscCall((*f)(F, S));
10289:     else PetscCall(MatDuplicate(F->schur, MAT_COPY_VALUES, S));
10290:   }
10291:   if (status) *status = F->schur_status;
10292:   PetscFunctionReturn(PETSC_SUCCESS);
10293: }

10295: /*@
10296:   MatFactorGetSchurComplement - Gets access to a Schur complement matrix using the current Schur data within a factored matrix

10298:   Logically Collective

10300:   Input Parameters:
10301: + F      - the factored matrix obtained by calling `MatGetFactor()`
10302: . S      - location where to return the Schur complement, can be `NULL`
10303: - status - the status of the Schur complement matrix, can be `NULL`

10305:   Level: advanced

10307:   Notes:
10308:   You must call `MatFactorSetSchurIS()` before calling this routine.

10310:   Schur complement mode is currently implemented for sequential matrices with factor type of `MATSOLVERMUMPS`

10312:   The routine returns a the Schur Complement stored within the data structures of the solver.

10314:   If `MatFactorInvertSchurComplement()` has previously been called, the returned matrix is actually the inverse of the Schur complement.

10316:   The returned matrix should not be destroyed; the caller should call `MatFactorRestoreSchurComplement()` when the object is no longer needed.

10318:   Use `MatFactorCreateSchurComplement()` to create a copy of the Schur complement matrix that is within a factored matrix

10320:   See `MatCreateSchurComplement()` or `MatGetSchurComplement()` for ways to create virtual or approximate Schur complements.

10322: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorRestoreSchurComplement()`, `MatFactorCreateSchurComplement()`, `MatFactorSchurStatus`
10323: @*/
10324: PetscErrorCode MatFactorGetSchurComplement(Mat F, Mat *S, MatFactorSchurStatus *status)
10325: {
10326:   PetscFunctionBegin;
10328:   if (S) {
10329:     PetscAssertPointer(S, 2);
10330:     *S = F->schur;
10331:   }
10332:   if (status) {
10333:     PetscAssertPointer(status, 3);
10334:     *status = F->schur_status;
10335:   }
10336:   PetscFunctionReturn(PETSC_SUCCESS);
10337: }

10339: static PetscErrorCode MatFactorUpdateSchurStatus_Private(Mat F)
10340: {
10341:   Mat S = F->schur;

10343:   PetscFunctionBegin;
10344:   switch (F->schur_status) {
10345:   case MAT_FACTOR_SCHUR_UNFACTORED: // fall-through
10346:   case MAT_FACTOR_SCHUR_INVERTED:
10347:     if (S) {
10348:       S->ops->solve             = NULL;
10349:       S->ops->matsolve          = NULL;
10350:       S->ops->solvetranspose    = NULL;
10351:       S->ops->matsolvetranspose = NULL;
10352:       S->ops->solveadd          = NULL;
10353:       S->ops->solvetransposeadd = NULL;
10354:       S->factortype             = MAT_FACTOR_NONE;
10355:       PetscCall(PetscFree(S->solvertype));
10356:     }
10357:   case MAT_FACTOR_SCHUR_FACTORED: // fall-through
10358:     break;
10359:   default:
10360:     SETERRQ(PetscObjectComm((PetscObject)F), PETSC_ERR_SUP, "Unhandled MatFactorSchurStatus %d", F->schur_status);
10361:   }
10362:   PetscFunctionReturn(PETSC_SUCCESS);
10363: }

10365: /*@
10366:   MatFactorRestoreSchurComplement - Restore the Schur complement matrix object obtained from a call to `MatFactorGetSchurComplement()`

10368:   Logically Collective

10370:   Input Parameters:
10371: + F      - the factored matrix obtained by calling `MatGetFactor()`
10372: . S      - location where the Schur complement is stored
10373: - status - the status of the Schur complement matrix (see `MatFactorSchurStatus`)

10375:   Level: advanced

10377: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorCreateSchurComplement()`, `MatFactorSchurStatus`
10378: @*/
10379: PetscErrorCode MatFactorRestoreSchurComplement(Mat F, Mat *S, MatFactorSchurStatus status)
10380: {
10381:   PetscFunctionBegin;
10383:   if (S) {
10385:     *S = NULL;
10386:   }
10387:   F->schur_status = status;
10388:   PetscCall(MatFactorUpdateSchurStatus_Private(F));
10389:   PetscFunctionReturn(PETSC_SUCCESS);
10390: }

10392: /*@
10393:   MatFactorSolveSchurComplementTranspose - Solve the transpose of the Schur complement system computed during the factorization step

10395:   Logically Collective

10397:   Input Parameters:
10398: + F   - the factored matrix obtained by calling `MatGetFactor()`
10399: . rhs - location where the right-hand side of the Schur complement system is stored
10400: - sol - location where the solution of the Schur complement system has to be returned

10402:   Level: advanced

10404:   Notes:
10405:   The sizes of the vectors should match the size of the Schur complement

10407:   Must be called after `MatFactorSetSchurIS()`

10409: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorSolveSchurComplement()`
10410: @*/
10411: PetscErrorCode MatFactorSolveSchurComplementTranspose(Mat F, Vec rhs, Vec sol)
10412: {
10413:   PetscFunctionBegin;
10420:   PetscCheckSameComm(F, 1, rhs, 2);
10421:   PetscCheckSameComm(F, 1, sol, 3);
10422:   PetscCall(MatFactorFactorizeSchurComplement(F));
10423:   switch (F->schur_status) {
10424:   case MAT_FACTOR_SCHUR_FACTORED:
10425:     PetscCall(MatSolveTranspose(F->schur, rhs, sol));
10426:     break;
10427:   case MAT_FACTOR_SCHUR_INVERTED:
10428:     PetscCall(MatMultTranspose(F->schur, rhs, sol));
10429:     break;
10430:   default:
10431:     SETERRQ(PetscObjectComm((PetscObject)F), PETSC_ERR_SUP, "Unhandled MatFactorSchurStatus %d", F->schur_status);
10432:   }
10433:   PetscFunctionReturn(PETSC_SUCCESS);
10434: }

10436: /*@
10437:   MatFactorSolveSchurComplement - Solve the Schur complement system computed during the factorization step

10439:   Logically Collective

10441:   Input Parameters:
10442: + F   - the factored matrix obtained by calling `MatGetFactor()`
10443: . rhs - location where the right-hand side of the Schur complement system is stored
10444: - sol - location where the solution of the Schur complement system has to be returned

10446:   Level: advanced

10448:   Notes:
10449:   The sizes of the vectors should match the size of the Schur complement

10451:   Must be called after `MatFactorSetSchurIS()`

10453: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorSolveSchurComplementTranspose()`
10454: @*/
10455: PetscErrorCode MatFactorSolveSchurComplement(Mat F, Vec rhs, Vec sol)
10456: {
10457:   PetscFunctionBegin;
10464:   PetscCheckSameComm(F, 1, rhs, 2);
10465:   PetscCheckSameComm(F, 1, sol, 3);
10466:   PetscCall(MatFactorFactorizeSchurComplement(F));
10467:   switch (F->schur_status) {
10468:   case MAT_FACTOR_SCHUR_FACTORED:
10469:     PetscCall(MatSolve(F->schur, rhs, sol));
10470:     break;
10471:   case MAT_FACTOR_SCHUR_INVERTED:
10472:     PetscCall(MatMult(F->schur, rhs, sol));
10473:     break;
10474:   default:
10475:     SETERRQ(PetscObjectComm((PetscObject)F), PETSC_ERR_SUP, "Unhandled MatFactorSchurStatus %d", F->schur_status);
10476:   }
10477:   PetscFunctionReturn(PETSC_SUCCESS);
10478: }

10480: PETSC_SINGLE_LIBRARY_INTERN PetscErrorCode MatSeqDenseInvertFactors_Private(Mat);
10481: #if PetscDefined(HAVE_CUDA)
10482: PETSC_SINGLE_LIBRARY_INTERN PetscErrorCode MatSeqDenseCUDAInvertFactors_Internal(Mat);
10483: #endif

10485: /* Schur status updated in the interface */
10486: static PetscErrorCode MatFactorInvertSchurComplement_Private(Mat F)
10487: {
10488:   Mat S = F->schur;

10490:   PetscFunctionBegin;
10491:   if (S) {
10492:     PetscMPIInt size;
10493:     PetscBool   isdense, isdensecuda;

10495:     PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)S), &size));
10496:     PetscCheck(size <= 1, PetscObjectComm((PetscObject)S), PETSC_ERR_SUP, "Not yet implemented");
10497:     PetscCall(PetscObjectTypeCompare((PetscObject)S, MATSEQDENSE, &isdense));
10498:     PetscCall(PetscObjectTypeCompare((PetscObject)S, MATSEQDENSECUDA, &isdensecuda));
10499:     PetscCheck(isdense || isdensecuda, PetscObjectComm((PetscObject)S), PETSC_ERR_SUP, "Not implemented for type %s", ((PetscObject)S)->type_name);
10500:     PetscCall(PetscLogEventBegin(MAT_FactorInvS, F, 0, 0, 0));
10501:     if (isdense) {
10502:       PetscCall(MatSeqDenseInvertFactors_Private(S));
10503:     } else if (isdensecuda) {
10504: #if PetscDefined(HAVE_CUDA)
10505:       PetscCall(MatSeqDenseCUDAInvertFactors_Internal(S));
10506: #endif
10507:     }
10508:     // HIP??????????????
10509:     PetscCall(PetscLogEventEnd(MAT_FactorInvS, F, 0, 0, 0));
10510:   }
10511:   PetscFunctionReturn(PETSC_SUCCESS);
10512: }

10514: /*@
10515:   MatFactorInvertSchurComplement - Invert the Schur complement matrix computed during the factorization step

10517:   Logically Collective

10519:   Input Parameter:
10520: . F - the factored matrix obtained by calling `MatGetFactor()`

10522:   Level: advanced

10524:   Notes:
10525:   Must be called after `MatFactorSetSchurIS()`.

10527:   Call `MatFactorGetSchurComplement()` or  `MatFactorCreateSchurComplement()` AFTER this call to actually compute the inverse and get access to it.

10529: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorGetSchurComplement()`, `MatFactorCreateSchurComplement()`
10530: @*/
10531: PetscErrorCode MatFactorInvertSchurComplement(Mat F)
10532: {
10533:   PetscFunctionBegin;
10536:   if (F->schur_status == MAT_FACTOR_SCHUR_INVERTED) PetscFunctionReturn(PETSC_SUCCESS);
10537:   PetscCall(MatFactorFactorizeSchurComplement(F));
10538:   PetscCall(MatFactorInvertSchurComplement_Private(F));
10539:   F->schur_status = MAT_FACTOR_SCHUR_INVERTED;
10540:   PetscFunctionReturn(PETSC_SUCCESS);
10541: }

10543: /*@
10544:   MatFactorFactorizeSchurComplement - Factorize the Schur complement matrix computed during the factorization step

10546:   Logically Collective

10548:   Input Parameter:
10549: . F - the factored matrix obtained by calling `MatGetFactor()`

10551:   Level: advanced

10553:   Note:
10554:   Must be called after `MatFactorSetSchurIS()`

10556: .seealso: [](ch_matrices), `Mat`, `MatGetFactor()`, `MatFactorSetSchurIS()`, `MatFactorInvertSchurComplement()`
10557: @*/
10558: PetscErrorCode MatFactorFactorizeSchurComplement(Mat F)
10559: {
10560:   MatFactorInfo info;

10562:   PetscFunctionBegin;
10565:   if (F->schur_status == MAT_FACTOR_SCHUR_INVERTED || F->schur_status == MAT_FACTOR_SCHUR_FACTORED) PetscFunctionReturn(PETSC_SUCCESS);
10566:   PetscCall(PetscLogEventBegin(MAT_FactorFactS, F, 0, 0, 0));
10567:   PetscCall(PetscMemzero(&info, sizeof(MatFactorInfo)));
10568:   if (F->factortype == MAT_FACTOR_CHOLESKY) { /* LDL^t regarded as Cholesky */
10569:     PetscCall(MatCholeskyFactor(F->schur, NULL, &info));
10570:   } else {
10571:     PetscCall(MatLUFactor(F->schur, NULL, NULL, &info));
10572:   }
10573:   PetscCall(PetscLogEventEnd(MAT_FactorFactS, F, 0, 0, 0));
10574:   F->schur_status = MAT_FACTOR_SCHUR_FACTORED;
10575:   PetscFunctionReturn(PETSC_SUCCESS);
10576: }

10578: /*@
10579:   MatPtAP - Creates the matrix product $C = P^T A P$

10581:   Neighbor-wise Collective

10583:   Input Parameters:
10584: + A     - the matrix
10585: . P     - the projection matrix
10586: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10587: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(P)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10588:           if the result is a dense matrix this is irrelevant

10590:   Output Parameter:
10591: . C - the product matrix

10593:   Level: intermediate

10595:   Notes:
10596:   `C` will be created and must be destroyed by the user with `MatDestroy()`.

10598:   This is a convenience routine that wraps the use of the `MatProductCreate()` with a `MatProductType` of `MATPRODUCT_PtAP`
10599:   functionality into a single function call. For more involved matrix-matrix operations see `MatProductCreate()`.

10601:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10603:   Developer Note:
10604:   For matrix types without special implementation the function fallbacks to `MatMatMult()` followed by `MatTransposeMatMult()`.

10606: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MatMatMult()`, `MatRARt()`
10607: @*/
10608: PetscErrorCode MatPtAP(Mat A, Mat P, MatReuse scall, PetscReal fill, Mat *C)
10609: {
10610:   PetscFunctionBegin;
10611:   if (scall == MAT_REUSE_MATRIX) MatCheckProduct(*C, 5);
10612:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");

10614:   if (scall == MAT_INITIAL_MATRIX) {
10615:     PetscCall(MatProductCreate(A, P, NULL, C));
10616:     PetscCall(MatProductSetType(*C, MATPRODUCT_PtAP));
10617:     PetscCall(MatProductSetAlgorithm(*C, "default"));
10618:     PetscCall(MatProductSetFill(*C, fill));

10620:     (*C)->product->api_user = PETSC_TRUE;
10621:     PetscCall(MatProductSetFromOptions(*C));
10622:     PetscCheck((*C)->ops->productsymbolic, PetscObjectComm((PetscObject)*C), PETSC_ERR_SUP, "MatProduct %s not supported for A %s and P %s", MatProductTypes[MATPRODUCT_PtAP], ((PetscObject)A)->type_name, ((PetscObject)P)->type_name);
10623:     PetscCall(MatProductSymbolic(*C));
10624:   } else { /* scall == MAT_REUSE_MATRIX */
10625:     PetscCall(MatProductReplaceMats(A, P, NULL, *C));
10626:   }

10628:   PetscCall(MatProductNumeric(*C));
10629:   if (A->symmetric == PETSC_BOOL3_TRUE) {
10630:     PetscCall(MatSetOption(*C, MAT_SYMMETRIC, PETSC_TRUE));
10631:     (*C)->spd = A->spd;
10632:   }
10633:   PetscFunctionReturn(PETSC_SUCCESS);
10634: }

10636: /*@
10637:   MatRARt - Creates the matrix product $C = R A R^T$

10639:   Neighbor-wise Collective

10641:   Input Parameters:
10642: + A     - the matrix
10643: . R     - the projection matrix
10644: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10645: - fill  - expected fill as ratio of nnz(C)/nnz(A), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10646:           if the result is a dense matrix this is irrelevant

10648:   Output Parameter:
10649: . C - the product matrix

10651:   Level: intermediate

10653:   Notes:
10654:   `C` will be created and must be destroyed by the user with `MatDestroy()`.

10656:   This is a convenience routine that wraps the use of the `MatProductCreate()` with a `MatProductType` of `MATPRODUCT_RARt`
10657:   functionality into a single function call. For more involved matrix-matrix operations see `MatProductCreate()`.

10659:   This routine is currently only implemented for pairs of `MATAIJ` matrices and classes
10660:   which inherit from `MATAIJ`. Due to PETSc sparse matrix block row distribution among processes,
10661:   the parallel `MatRARt()` is implemented computing the explicit transpose of `R`, which can be very expensive.
10662:   We recommend using `MatPtAP()` when possible.

10664:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10666: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MatMatMult()`, `MatPtAP()`
10667: @*/
10668: PetscErrorCode MatRARt(Mat A, Mat R, MatReuse scall, PetscReal fill, Mat *C)
10669: {
10670:   PetscFunctionBegin;
10671:   if (scall == MAT_REUSE_MATRIX) MatCheckProduct(*C, 5);
10672:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");

10674:   if (scall == MAT_INITIAL_MATRIX) {
10675:     PetscCall(MatProductCreate(A, R, NULL, C));
10676:     PetscCall(MatProductSetType(*C, MATPRODUCT_RARt));
10677:     PetscCall(MatProductSetAlgorithm(*C, "default"));
10678:     PetscCall(MatProductSetFill(*C, fill));

10680:     (*C)->product->api_user = PETSC_TRUE;
10681:     PetscCall(MatProductSetFromOptions(*C));
10682:     PetscCheck((*C)->ops->productsymbolic, PetscObjectComm((PetscObject)*C), PETSC_ERR_SUP, "MatProduct %s not supported for A %s and R %s", MatProductTypes[MATPRODUCT_RARt], ((PetscObject)A)->type_name, ((PetscObject)R)->type_name);
10683:     PetscCall(MatProductSymbolic(*C));
10684:   } else { /* scall == MAT_REUSE_MATRIX */
10685:     PetscCall(MatProductReplaceMats(A, R, NULL, *C));
10686:   }

10688:   PetscCall(MatProductNumeric(*C));
10689:   if (A->symmetric == PETSC_BOOL3_TRUE) PetscCall(MatSetOption(*C, MAT_SYMMETRIC, PETSC_TRUE));
10690:   PetscFunctionReturn(PETSC_SUCCESS);
10691: }

10693: /* MatProductComputeWithMat_Private - Computes D = A * B or D = A^T * B into an existing matrix D, keeping the product on a dense D

10695:    Collective

10697:    Input Parameters:
10698: +  A     - the left matrix
10699: .  B     - the right matrix
10700: .  ptype - MATPRODUCT_AB or MATPRODUCT_AtB
10701: -  D     - the result, of the size of the product

10703:    Level: developer

10705:    Notes:
10706:    For a dense D, this routine keeps the product on D between calls, so only the first call runs the symbolic phase. The product is created
10707:    again only when ptype, A, or the nonzero pattern of A changes; a different B of the same size and type reuses it. The kept product holds
10708:    references to A and B until MatProductClear() is called on D or D is destroyed. In contrast, MatMatMult() with MAT_REUSE_MATRIX creates the
10709:    product and destroys it again on every call into a dense D that does not already have a product.

10711:    For any other D, which must already have a product, this calls MatMatMult() or MatTransposeMatMult() with MAT_REUSE_MATRIX.

10713:    Developer Note:
10714:    The nonzero state of A is compared without a reduction, since the parallel AIJ and BAIJ types make it the same on all processes during
10715:    assembly.

10717: .seealso: `MatMatMult()`, `MatTransposeMatMult()`, `MatProductReplaceMats()`, `PCMGMatResidualDefault()`
10718: */
10719: PetscErrorCode MatProductComputeWithMat_Private(Mat A, Mat B, MatProductType ptype, Mat D)
10720: {
10721:   Mat_Product     *product = D->product;
10722:   PetscObjectState state;
10723:   PetscBool        flg;

10725:   PetscFunctionBegin;
10726:   PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)D, &flg, MATSEQDENSE, MATMPIDENSE, ""));
10727:   if (!flg) { /* only a dense result can be given without a product, MatMatMult() and MatTransposeMatMult() reuse the product of any other */
10728:     if (ptype == MATPRODUCT_AB) PetscCall(MatMatMult(A, B, MAT_REUSE_MATRIX, PETSC_CURRENT, &D));
10729:     else PetscCall(MatTransposeMatMult(A, B, MAT_REUSE_MATRIX, PETSC_CURRENT, &D));
10730:     PetscFunctionReturn(PETSC_SUCCESS);
10731:   }
10732:   PetscCall(MatGetNonzeroState(A, &state));
10733:   if (product == NULL || product->type != ptype || product->A != A || product->Anonzerostate != state) {
10734:     PetscCall(PetscInfo(D, "Setting up the %s product into the supplied dense matrix\n", MatProductTypes[ptype]));
10735:     PetscCall(MatProductCreateWithMat(A, B, NULL, D));
10736:     D->product->api_user = PETSC_TRUE;
10737:     PetscCall(MatProductSetType(D, ptype));
10738:     PetscCall(MatProductSetFromOptions(D));
10739:     PetscCall(MatProductSymbolic(D));
10740:   } else {
10741:     PetscCall(PetscInfo(D, "Reusing the %s product attached to the supplied dense matrix\n", MatProductTypes[ptype]));
10742:     if (product->B != B) PetscCall(MatProductReplaceMats(NULL, B, NULL, D));
10743:   }
10744:   PetscCall(MatProductNumeric(D));
10745:   PetscFunctionReturn(PETSC_SUCCESS);
10746: }

10748: static PetscErrorCode MatProduct_Private(Mat A, Mat B, MatReuse scall, PetscReal fill, MatProductType ptype, Mat *C)
10749: {
10750:   PetscBool flg = PETSC_TRUE;

10752:   PetscFunctionBegin;
10753:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "MAT_INPLACE_MATRIX product not supported");
10754:   if (scall == MAT_INITIAL_MATRIX) {
10755:     PetscCall(PetscInfo(A, "Calling MatProduct API with MAT_INITIAL_MATRIX and product type %s\n", MatProductTypes[ptype]));
10756:     PetscCall(MatProductCreate(A, B, NULL, C));
10757:     PetscCall(MatProductSetAlgorithm(*C, MATPRODUCTALGORITHMDEFAULT));
10758:     PetscCall(MatProductSetFill(*C, fill));
10759:   } else { /* scall == MAT_REUSE_MATRIX */
10760:     Mat_Product *product = (*C)->product;

10762:     PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)*C, &flg, MATSEQDENSE, MATMPIDENSE, ""));
10763:     if (flg && product && product->type != ptype) {
10764:       PetscCall(MatProductClear(*C));
10765:       product = NULL;
10766:     }
10767:     PetscCall(PetscInfo(A, "Calling MatProduct API with MAT_REUSE_MATRIX %s product present and product type %s\n", product ? "with" : "without", MatProductTypes[ptype]));
10768:     if (!product) { /* user provide the dense matrix *C without calling MatProductCreate() or reusing it from previous calls */
10769:       PetscCheck(flg, PetscObjectComm((PetscObject)*C), PETSC_ERR_SUP, "Call MatProductCreate() first");
10770:       PetscCall(MatProductCreate_Private(A, B, NULL, *C));
10771:       product        = (*C)->product;
10772:       product->fill  = fill;
10773:       product->clear = PETSC_TRUE;
10774:     } else { /* user may change input matrices A or B when MAT_REUSE_MATRIX */
10775:       flg = PETSC_FALSE;
10776:       PetscCall(MatProductReplaceMats(A, B, NULL, *C));
10777:     }
10778:   }
10779:   if (flg) {
10780:     (*C)->product->api_user = PETSC_TRUE;
10781:     PetscCall(MatProductSetType(*C, ptype));
10782:     PetscCall(MatProductSetFromOptions(*C));
10783:     PetscCall(MatProductSymbolic(*C));
10784:   }
10785:   PetscCall(MatProductNumeric(*C));
10786:   PetscFunctionReturn(PETSC_SUCCESS);
10787: }

10789: /*@
10790:   MatMatMult - Performs matrix-matrix multiplication $C=A B$.

10792:   Neighbor-wise Collective

10794:   Input Parameters:
10795: + A     - the left matrix
10796: . B     - the right matrix
10797: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10798: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10799:           if the result is a dense matrix this is irrelevant

10801:   Output Parameter:
10802: . C - the product matrix

10804:   Notes:
10805:   Unless scall is `MAT_REUSE_MATRIX` C will be created.

10807:   `MAT_REUSE_MATRIX` can only be used if the matrices A and B have the same nonzero pattern as in the previous call and C was obtained from a previous
10808:   call to this function with `MAT_INITIAL_MATRIX`.

10810:   To determine the correct fill value, run with `-info` and search for the string "Fill ratio" to see the value actually needed.

10812:   In the special case where matrix `B` (and hence `C`) are dense you can create the correctly sized matrix `C` yourself and then call this routine with `MAT_REUSE_MATRIX`,
10813:   rather than first having `MatMatMult()` create it for you. You can NEVER do this if the matrix `C` is sparse.

10815:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10817:   This is a convenience routine that wraps the use of the `MatProductCreate()` with a `MatProductType` of `MATPRODUCT_AB`
10818:   functionality into a single function call. For more involved matrix-matrix operations see `MatProductCreate()`.

10820:   Example of Usage:
10821: .vb
10822:      MatProductCreate(A,B,NULL,&C);
10823:      MatProductSetType(C,MATPRODUCT_AB);
10824:      MatProductSymbolic(C);
10825:      MatProductNumeric(C); // compute C=A * B
10826:      MatProductReplaceMats(A1,B1,NULL,C); // compute C=A1 * B1
10827:      MatProductNumeric(C);
10828:      MatProductReplaceMats(A2,NULL,NULL,C); // compute C=A2 * B1
10829:      MatProductNumeric(C);
10830: .ve

10832:   Level: intermediate

10834: .seealso: [](ch_matrices), `Mat`, `MatProductType`, `MATPRODUCT_AB`, `MatTransposeMatMult()`, `MatMatTransposeMult()`, `MatPtAP()`, `MatProductCreate()`, `MatProductSymbolic()`, `MatProductReplaceMats()`, `MatProductNumeric()`
10835: @*/
10836: PetscErrorCode MatMatMult(Mat A, Mat B, MatReuse scall, PetscReal fill, Mat *C)
10837: {
10838:   PetscFunctionBegin;
10839:   PetscCall(MatProduct_Private(A, B, scall, fill, MATPRODUCT_AB, C));
10840:   PetscFunctionReturn(PETSC_SUCCESS);
10841: }

10843: /*@
10844:   MatMatTransposeMult - Performs matrix-matrix multiplication $C = A B^T$.

10846:   Neighbor-wise Collective

10848:   Input Parameters:
10849: + A     - the left matrix
10850: . B     - the right matrix
10851: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10852: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if not known

10854:   Output Parameter:
10855: . C - the product matrix

10857:   Options Database Key:
10858: . -matmattransmult_mpidense_mpidense_via {allgatherv,cyclic} - Choose between algorithms for `MATMPIDENSE` matrices: the
10859:               first redundantly copies the transposed `B` matrix on each process and requires O(log P) communication complexity;
10860:               the second never stores more than one portion of the `B` matrix at a time but requires O(P) communication complexity.

10862:   Level: intermediate

10864:   Notes:
10865:   C will be created if `MAT_INITIAL_MATRIX` and must be destroyed by the user with `MatDestroy()`.

10867:   `MAT_REUSE_MATRIX` can only be used if the matrices A and B have the same nonzero pattern as in the previous call

10869:   To determine the correct fill value, run with -info and search for the string "Fill ratio" to see the value
10870:   actually needed.

10872:   This routine is currently only implemented for pairs of `MATSEQAIJ` matrices, for the `MATSEQDENSE` class,
10873:   and for pairs of `MATMPIDENSE` matrices.

10875:   This is a convenience routine that wraps the use of the `MatProductCreate()` with a `MatProductType` of `MATPRODUCT_ABt`
10876:   functionality into a single function call. For more involved matrix-matrix operations see `MatProductCreate()`.

10878:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10880: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MATPRODUCT_ABt`, `MatMatMult()`, `MatTransposeMatMult()`, `MatPtAP()`, `MatProductAlgorithm`, `MatProductType`
10881: @*/
10882: PetscErrorCode MatMatTransposeMult(Mat A, Mat B, MatReuse scall, PetscReal fill, Mat *C)
10883: {
10884:   PetscFunctionBegin;
10885:   PetscCall(MatProduct_Private(A, B, scall, fill, MATPRODUCT_ABt, C));
10886:   if (A == B) PetscCall(MatSetOption(*C, MAT_SYMMETRIC, PETSC_TRUE));
10887:   PetscFunctionReturn(PETSC_SUCCESS);
10888: }

10890: /*@
10891:   MatTransposeMatMult - Performs matrix-matrix multiplication $C = A^T B$.

10893:   Neighbor-wise Collective

10895:   Input Parameters:
10896: + A     - the left matrix
10897: . B     - the right matrix
10898: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10899: - fill  - expected fill as ratio of nnz(C)/(nnz(A) + nnz(B)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if not known

10901:   Output Parameter:
10902: . C - the product matrix

10904:   Level: intermediate

10906:   Notes:
10907:   `C` will be created if `MAT_INITIAL_MATRIX` and must be destroyed by the user with `MatDestroy()`.

10909:   `MAT_REUSE_MATRIX` can only be used if `A` and `B` have the same nonzero pattern as in the previous call.

10911:   This is a convenience routine that wraps the use of `MatProductCreate()` with a `MatProductType` of `MATPRODUCT_AtB`
10912:   functionality into a single function call. For more involved matrix-matrix operations see `MatProductCreate()`.

10914:   To determine the correct fill value, run with -info and search for the string "Fill ratio" to see the value
10915:   actually needed.

10917:   This routine is currently implemented for pairs of `MATAIJ` matrices and pairs of `MATSEQDENSE` matrices and classes
10918:   which inherit from `MATSEQAIJ`. `C` will be of the same type as the input matrices.

10920:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10922: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MATPRODUCT_AtB`, `MatMatMult()`, `MatMatTransposeMult()`, `MatPtAP()`
10923: @*/
10924: PetscErrorCode MatTransposeMatMult(Mat A, Mat B, MatReuse scall, PetscReal fill, Mat *C)
10925: {
10926:   PetscFunctionBegin;
10927:   PetscCall(MatProduct_Private(A, B, scall, fill, MATPRODUCT_AtB, C));
10928:   PetscFunctionReturn(PETSC_SUCCESS);
10929: }

10931: /*@
10932:   MatMatMatMult - Performs matrix-matrix-matrix multiplication D=A*B*C.

10934:   Neighbor-wise Collective

10936:   Input Parameters:
10937: + A     - the left matrix
10938: . B     - the middle matrix
10939: . C     - the right matrix
10940: . scall - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
10941: - fill  - expected fill as ratio of nnz(D)/(nnz(A) + nnz(B)+nnz(C)), use `PETSC_DETERMINE` or `PETSC_CURRENT` if you do not have a good estimate
10942:           if the result is a dense matrix this is irrelevant

10944:   Output Parameter:
10945: . D - the product matrix

10947:   Level: intermediate

10949:   Notes:
10950:   Unless `scall` is `MAT_REUSE_MATRIX` `D` will be created.

10952:   `MAT_REUSE_MATRIX` can only be used if the matrices `A`, `B`, and `C` have the same nonzero pattern as in the previous call

10954:   This is a convenience routine that wraps the use of the `MatProductCreate()` with a `MatProductType` of `MATPRODUCT_ABC`
10955:   functionality into a single function call. For more involved matrix-matrix operations see `MatProductCreate()`.

10957:   To determine the correct fill value, run with `-info` and search for the string "Fill ratio" to see the value
10958:   actually needed.

10960:   If you have many matrices with the same non-zero structure to multiply, you
10961:   should use `MAT_REUSE_MATRIX` in all calls but the first

10963:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

10965: .seealso: [](ch_matrices), `Mat`, `MatProductCreate()`, `MATPRODUCT_ABC`, `MatMatMult`, `MatPtAP()`, `MatMatTransposeMult()`, `MatTransposeMatMult()`
10966: @*/
10967: PetscErrorCode MatMatMatMult(Mat A, Mat B, Mat C, MatReuse scall, PetscReal fill, Mat *D)
10968: {
10969:   PetscFunctionBegin;
10970:   if (scall == MAT_REUSE_MATRIX) MatCheckProduct(*D, 6);
10971:   PetscCheck(scall != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");

10973:   if (scall == MAT_INITIAL_MATRIX) {
10974:     PetscCall(MatProductCreate(A, B, C, D));
10975:     PetscCall(MatProductSetType(*D, MATPRODUCT_ABC));
10976:     PetscCall(MatProductSetAlgorithm(*D, "default"));
10977:     PetscCall(MatProductSetFill(*D, fill));

10979:     (*D)->product->api_user = PETSC_TRUE;
10980:     PetscCall(MatProductSetFromOptions(*D));
10981:     PetscCheck((*D)->ops->productsymbolic, PetscObjectComm((PetscObject)*D), PETSC_ERR_SUP, "MatProduct %s not supported for A %s, B %s and C %s", MatProductTypes[MATPRODUCT_ABC], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name,
10982:                ((PetscObject)C)->type_name);
10983:     PetscCall(MatProductSymbolic(*D));
10984:   } else { /* user may change input matrices when REUSE */
10985:     PetscCall(MatProductReplaceMats(A, B, C, *D));
10986:   }
10987:   PetscCall(MatProductNumeric(*D));
10988:   PetscFunctionReturn(PETSC_SUCCESS);
10989: }

10991: /*@
10992:   MatCreateRedundantMatrix - Create redundant matrices and put them into processes of subcommunicators.

10994:   Collective

10996:   Input Parameters:
10997: + mat      - the matrix
10998: . nsubcomm - the number of subcommunicators (= number of redundant parallel or sequential matrices)
10999: . subcomm  - MPI communicator split from the communicator where mat resides in (or `MPI_COMM_NULL` if nsubcomm is used)
11000: - reuse    - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

11002:   Output Parameter:
11003: . matredundant - redundant matrix

11005:   Level: advanced

11007:   Notes:
11008:   `MAT_REUSE_MATRIX` can only be used when the nonzero structure of the
11009:   original matrix has not changed from that last call to `MatCreateRedundantMatrix()`.

11011:   This routine creates the duplicated matrices in the subcommunicators; you should NOT create them before
11012:   calling it.

11014:   `PetscSubcommCreate()` can be used to manage the creation of the subcomm but need not be.

11016: .seealso: [](ch_matrices), `Mat`, `MatDestroy()`, `PetscSubcommCreate()`, `PetscSubcomm`
11017: @*/
11018: PetscErrorCode MatCreateRedundantMatrix(Mat mat, PetscInt nsubcomm, MPI_Comm subcomm, MatReuse reuse, Mat *matredundant)
11019: {
11020:   MPI_Comm       comm;
11021:   PetscMPIInt    size;
11022:   PetscInt       mloc_sub, nloc_sub, rstart, rend, M = mat->rmap->N, N = mat->cmap->N, bs = mat->rmap->bs;
11023:   Mat_Redundant *redund     = NULL;
11024:   PetscSubcomm   psubcomm   = NULL;
11025:   MPI_Comm       subcomm_in = subcomm;
11026:   Mat           *matseq;
11027:   IS             isrow, iscol;
11028:   PetscBool      newsubcomm = PETSC_FALSE;

11030:   PetscFunctionBegin;
11032:   if (nsubcomm && reuse == MAT_REUSE_MATRIX) {
11033:     PetscAssertPointer(*matredundant, 5);
11035:   }

11037:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));
11038:   if (size == 1 || nsubcomm == 1) {
11039:     if (reuse == MAT_INITIAL_MATRIX) {
11040:       PetscCall(MatDuplicate(mat, MAT_COPY_VALUES, matredundant));
11041:     } else {
11042:       PetscCheck(*matredundant != mat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");
11043:       PetscCall(MatCopy(mat, *matredundant, SAME_NONZERO_PATTERN));
11044:     }
11045:     PetscFunctionReturn(PETSC_SUCCESS);
11046:   }

11048:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
11049:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
11050:   MatCheckPreallocated(mat, 1);

11052:   PetscCall(PetscLogEventBegin(MAT_RedundantMat, mat, 0, 0, 0));
11053:   if (subcomm_in == MPI_COMM_NULL && reuse == MAT_INITIAL_MATRIX) { /* get subcomm if user does not provide subcomm */
11054:     /* create psubcomm, then get subcomm */
11055:     PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
11056:     PetscCallMPI(MPI_Comm_size(comm, &size));
11057:     PetscCheck(nsubcomm >= 1 && nsubcomm <= size, PETSC_COMM_SELF, PETSC_ERR_ARG_SIZ, "nsubcomm must between 1 and %d", size);

11059:     PetscCall(PetscSubcommCreate(comm, &psubcomm));
11060:     PetscCall(PetscSubcommSetNumber(psubcomm, nsubcomm));
11061:     PetscCall(PetscSubcommSetType(psubcomm, PETSC_SUBCOMM_CONTIGUOUS));
11062:     PetscCall(PetscSubcommSetFromOptions(psubcomm));
11063:     PetscCall(PetscCommDuplicate(PetscSubcommChild(psubcomm), &subcomm, NULL));
11064:     newsubcomm = PETSC_TRUE;
11065:     PetscCall(PetscSubcommDestroy(&psubcomm));
11066:   }

11068:   /* get isrow, iscol and a local sequential matrix matseq[0] */
11069:   if (reuse == MAT_INITIAL_MATRIX) {
11070:     mloc_sub = PETSC_DECIDE;
11071:     nloc_sub = PETSC_DECIDE;
11072:     if (bs < 1) {
11073:       PetscCall(PetscSplitOwnership(subcomm, &mloc_sub, &M));
11074:       PetscCall(PetscSplitOwnership(subcomm, &nloc_sub, &N));
11075:     } else {
11076:       PetscCall(PetscSplitOwnershipBlock(subcomm, bs, &mloc_sub, &M));
11077:       PetscCall(PetscSplitOwnershipBlock(subcomm, bs, &nloc_sub, &N));
11078:     }
11079:     PetscCallMPI(MPI_Scan(&mloc_sub, &rend, 1, MPIU_INT, MPI_SUM, subcomm));
11080:     rstart = rend - mloc_sub;
11081:     PetscCall(ISCreateStride(PETSC_COMM_SELF, mloc_sub, rstart, 1, &isrow));
11082:     PetscCall(ISCreateStride(PETSC_COMM_SELF, N, 0, 1, &iscol));
11083:     PetscCall(ISSetIdentity(iscol));
11084:   } else { /* reuse == MAT_REUSE_MATRIX */
11085:     PetscCheck(*matredundant != mat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");
11086:     /* retrieve subcomm */
11087:     PetscCall(PetscObjectGetComm((PetscObject)*matredundant, &subcomm));
11088:     redund = (*matredundant)->redundant;
11089:     isrow  = redund->isrow;
11090:     iscol  = redund->iscol;
11091:     matseq = redund->matseq;
11092:   }
11093:   PetscCall(MatCreateSubMatrices(mat, 1, &isrow, &iscol, reuse, &matseq));

11095:   /* get matredundant over subcomm */
11096:   if (reuse == MAT_INITIAL_MATRIX) {
11097:     PetscCall(MatCreateMPIMatConcatenateSeqMat(subcomm, matseq[0], nloc_sub, reuse, matredundant));

11099:     /* create a supporting struct and attach it to C for reuse */
11100:     PetscCall(PetscNew(&redund));
11101:     (*matredundant)->redundant = redund;
11102:     redund->isrow              = isrow;
11103:     redund->iscol              = iscol;
11104:     redund->matseq             = matseq;
11105:     if (newsubcomm) {
11106:       redund->subcomm = subcomm;
11107:     } else {
11108:       redund->subcomm = MPI_COMM_NULL;
11109:     }
11110:   } else {
11111:     PetscCall(MatCreateMPIMatConcatenateSeqMat(subcomm, matseq[0], PETSC_DECIDE, reuse, matredundant));
11112:   }
11113: #if PetscDefined(HAVE_VIENNACL) || PetscDefined(HAVE_CUDA) || PetscDefined(HAVE_HIP)
11114:   if (matseq[0]->boundtocpu && matseq[0]->bindingpropagates) {
11115:     PetscCall(MatBindToCPU(*matredundant, PETSC_TRUE));
11116:     PetscCall(MatSetBindingPropagates(*matredundant, PETSC_TRUE));
11117:   }
11118: #endif
11119:   PetscCall(PetscLogEventEnd(MAT_RedundantMat, mat, 0, 0, 0));
11120:   PetscFunctionReturn(PETSC_SUCCESS);
11121: }

11123: /*@
11124:   MatGetMultiProcBlock - Create multiple 'parallel submatrices' from
11125:   a given `Mat`. Each submatrix can span multiple procs.

11127:   Collective

11129:   Input Parameters:
11130: + mat     - the matrix
11131: . subComm - the sub communicator obtained as if by `MPI_Comm_split(PetscObjectComm((PetscObject)mat))`
11132: - scall   - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

11134:   Output Parameter:
11135: . subMat - parallel sub-matrices each spanning a given `subcomm`

11137:   Level: advanced

11139:   Notes:
11140:   The submatrix partition across processes is dictated by `subComm` a
11141:   communicator obtained by `MPI_comm_split()` or via `PetscSubcommCreate()`. The `subComm`
11142:   is not restricted to be grouped with consecutive original MPI processes.

11144:   Due the `MPI_Comm_split()` usage, the parallel layout of the submatrices
11145:   map directly to the layout of the original matrix [wrt the local
11146:   row,col partitioning]. So the original 'DiagonalMat' naturally maps
11147:   into the 'DiagonalMat' of the `subMat`, hence it is used directly from
11148:   the `subMat`. However the offDiagMat looses some columns - and this is
11149:   reconstructed with `MatSetValues()`

11151:   This is used by `PCBJACOBI` when a single block spans multiple MPI processes.

11153: .seealso: [](ch_matrices), `Mat`, `MatCreateRedundantMatrix()`, `MatCreateSubMatrices()`, `PCBJACOBI`
11154: @*/
11155: PetscErrorCode MatGetMultiProcBlock(Mat mat, MPI_Comm subComm, MatReuse scall, Mat *subMat)
11156: {
11157:   PetscMPIInt commsize, subCommSize;

11159:   PetscFunctionBegin;
11160:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &commsize));
11161:   PetscCallMPI(MPI_Comm_size(subComm, &subCommSize));
11162:   PetscCheck(subCommSize <= commsize, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_OUTOFRANGE, "CommSize %d < SubCommZize %d", commsize, subCommSize);

11164:   PetscCheck(scall != MAT_REUSE_MATRIX || *subMat != mat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");
11165:   PetscCall(PetscLogEventBegin(MAT_GetMultiProcBlock, mat, 0, 0, 0));
11166:   PetscUseTypeMethod(mat, getmultiprocblock, subComm, scall, subMat);
11167:   PetscCall(PetscLogEventEnd(MAT_GetMultiProcBlock, mat, 0, 0, 0));
11168:   PetscFunctionReturn(PETSC_SUCCESS);
11169: }

11171: /*@
11172:   MatGetLocalSubMatrix - Gets a reference to a submatrix specified in local numbering

11174:   Not Collective

11176:   Input Parameters:
11177: + mat   - matrix to extract local submatrix from
11178: . isrow - local row indices for submatrix
11179: - iscol - local column indices for submatrix

11181:   Output Parameter:
11182: . submat - the submatrix

11184:   Level: intermediate

11186:   Notes:
11187:   `submat` should be disposed of with `MatRestoreLocalSubMatrix()`.

11189:   Depending on the format of `mat`, the returned `submat` may not implement `MatMult()`. Its communicator may be
11190:   the same as `mat`, it may be `PETSC_COMM_SELF`, or some other sub-communictor of `mat`'s.

11192:   `submat` always implements `MatSetValuesLocal()`. If `isrow` and `iscol` have the same block size, then
11193:   `MatSetValuesBlockedLocal()` will also be implemented.

11195:   `mat` must have had a `ISLocalToGlobalMapping` provided to it with `MatSetLocalToGlobalMapping()`.
11196:   Matrices obtained with `DMCreateMatrix()` generally already have the local to global mapping provided.

11198: .seealso: [](ch_matrices), `Mat`, `MatRestoreLocalSubMatrix()`, `MatCreateLocalRef()`, `MatSetLocalToGlobalMapping()`
11199: @*/
11200: PetscErrorCode MatGetLocalSubMatrix(Mat mat, IS isrow, IS iscol, Mat *submat)
11201: {
11202:   PetscFunctionBegin;
11206:   PetscCheckSameComm(isrow, 2, iscol, 3);
11207:   PetscAssertPointer(submat, 4);
11208:   PetscCheck(mat->rmap->mapping, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Matrix must have local to global mapping provided before this call");

11210:   if (mat->ops->getlocalsubmatrix) {
11211:     PetscUseTypeMethod(mat, getlocalsubmatrix, isrow, iscol, submat);
11212:   } else {
11213:     PetscCall(MatCreateLocalRef(mat, isrow, iscol, submat));
11214:   }
11215:   (*submat)->assembled = mat->assembled;
11216:   PetscFunctionReturn(PETSC_SUCCESS);
11217: }

11219: /*@
11220:   MatRestoreLocalSubMatrix - Restores a reference to a submatrix specified in local numbering obtained with `MatGetLocalSubMatrix()`

11222:   Not Collective

11224:   Input Parameters:
11225: + mat    - matrix to extract local submatrix from
11226: . isrow  - local row indices for submatrix
11227: . iscol  - local column indices for submatrix
11228: - submat - the submatrix

11230:   Level: intermediate

11232: .seealso: [](ch_matrices), `Mat`, `MatGetLocalSubMatrix()`
11233: @*/
11234: PetscErrorCode MatRestoreLocalSubMatrix(Mat mat, IS isrow, IS iscol, Mat *submat)
11235: {
11236:   PetscFunctionBegin;
11240:   PetscCheckSameComm(isrow, 2, iscol, 3);
11241:   PetscAssertPointer(submat, 4);

11244:   if (mat->ops->restorelocalsubmatrix) {
11245:     PetscUseTypeMethod(mat, restorelocalsubmatrix, isrow, iscol, submat);
11246:   } else {
11247:     PetscCall(MatDestroy(submat));
11248:   }
11249:   *submat = NULL;
11250:   PetscFunctionReturn(PETSC_SUCCESS);
11251: }

11253: /*@
11254:   MatFindZeroDiagonals - Finds all the rows of a matrix that have zero or no diagonal entry in the matrix

11256:   Collective

11258:   Input Parameter:
11259: . mat - the matrix

11261:   Output Parameter:
11262: . is - if any rows have zero diagonals this contains the list of them

11264:   Level: developer

11266: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
11267: @*/
11268: PetscErrorCode MatFindZeroDiagonals(Mat mat, IS *is)
11269: {
11270:   PetscFunctionBegin;
11273:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
11274:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

11276:   if (!mat->ops->findzerodiagonals) {
11277:     Vec                diag;
11278:     const PetscScalar *a;
11279:     PetscInt          *rows;
11280:     PetscInt           rStart, rEnd, r, nrow = 0;

11282:     PetscCall(MatCreateVecs(mat, &diag, NULL));
11283:     PetscCall(MatGetDiagonal(mat, diag));
11284:     PetscCall(MatGetOwnershipRange(mat, &rStart, &rEnd));
11285:     PetscCall(VecGetArrayRead(diag, &a));
11286:     for (r = 0; r < rEnd - rStart; ++r)
11287:       if (a[r] == 0.0) ++nrow;
11288:     PetscCall(PetscMalloc1(nrow, &rows));
11289:     nrow = 0;
11290:     for (r = 0; r < rEnd - rStart; ++r)
11291:       if (a[r] == 0.0) rows[nrow++] = r + rStart;
11292:     PetscCall(VecRestoreArrayRead(diag, &a));
11293:     PetscCall(VecDestroy(&diag));
11294:     PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), nrow, rows, PETSC_OWN_POINTER, is));
11295:   } else {
11296:     PetscUseTypeMethod(mat, findzerodiagonals, is);
11297:   }
11298:   PetscFunctionReturn(PETSC_SUCCESS);
11299: }

11301: /*@
11302:   MatFindOffBlockDiagonalEntries - Finds all the rows of a matrix that have entries outside of the main diagonal block (defined by the matrix block size)

11304:   Collective

11306:   Input Parameter:
11307: . mat - the matrix

11309:   Output Parameter:
11310: . is - contains the list of rows with off block diagonal entries

11312:   Level: developer

11314: .seealso: [](ch_matrices), `Mat`, `MatMultTranspose()`, `MatMultAdd()`, `MatMultTransposeAdd()`
11315: @*/
11316: PetscErrorCode MatFindOffBlockDiagonalEntries(Mat mat, IS *is)
11317: {
11318:   PetscFunctionBegin;
11321:   PetscCheck(mat->assembled, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
11322:   PetscCheck(!mat->factortype, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");

11324:   PetscUseTypeMethod(mat, findoffblockdiagonalentries, is);
11325:   PetscFunctionReturn(PETSC_SUCCESS);
11326: }

11328: /*@
11329:   MatInvertBlockDiagonal - Inverts the block diagonal entries.

11331:   Collective; No Fortran Support

11333:   Input Parameter:
11334: . mat - the matrix

11336:   Output Parameter:
11337: . values - the block inverses in column major order (FORTRAN-like)

11339:   Level: advanced

11341:   Notes:
11342:   The size of the blocks is determined by the block size of the matrix.

11344:   The blocks never overlap between two MPI processes, use `MatInvertVariableBlockEnvelope()` for that case

11346:   The blocks all have the same size, use `MatInvertVariableBlockDiagonal()` for variable block size

11348: .seealso: [](ch_matrices), `Mat`, `MatInvertVariableBlockEnvelope()`, `MatInvertBlockDiagonalMat()`
11349: @*/
11350: PetscErrorCode MatInvertBlockDiagonal(Mat mat, const PetscScalar *values[])
11351: {
11352:   PetscFunctionBegin;
11354:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
11355:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
11356:   PetscUseTypeMethod(mat, invertblockdiagonal, values);
11357:   PetscFunctionReturn(PETSC_SUCCESS);
11358: }

11360: /*@
11361:   MatInvertVariableBlockDiagonal - Inverts the point block diagonal entries.

11363:   Collective; No Fortran Support

11365:   Input Parameters:
11366: + mat     - the matrix
11367: . nblocks - the number of blocks on the process, set with `MatSetVariableBlockSizes()`
11368: - bsizes  - the size of each block on the process, set with `MatSetVariableBlockSizes()`

11370:   Output Parameter:
11371: . values - the block inverses in column major order (FORTRAN-like)

11373:   Level: advanced

11375:   Notes:
11376:   Use `MatInvertBlockDiagonal()` if all blocks have the same size

11378:   The blocks never overlap between two MPI processes, use `MatInvertVariableBlockEnvelope()` for that case

11380: .seealso: [](ch_matrices), `Mat`, `MatInvertBlockDiagonal()`, `MatSetVariableBlockSizes()`, `MatInvertVariableBlockEnvelope()`
11381: @*/
11382: PetscErrorCode MatInvertVariableBlockDiagonal(Mat mat, PetscInt nblocks, const PetscInt bsizes[], PetscScalar values[])
11383: {
11384:   PetscFunctionBegin;
11386:   PetscCheck(mat->assembled, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for unassembled matrix");
11387:   PetscCheck(!mat->factortype, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Not for factored matrix");
11388:   PetscUseTypeMethod(mat, invertvariableblockdiagonal, nblocks, bsizes, values);
11389:   PetscFunctionReturn(PETSC_SUCCESS);
11390: }

11392: /*@
11393:   MatInvertBlockDiagonalMat - set the values of matrix C to be the inverted block diagonal of matrix A

11395:   Collective

11397:   Input Parameters:
11398: + A - the matrix
11399: - C - matrix with inverted block diagonal of `A`. This matrix should be created and may have its type set.

11401:   Level: advanced

11403:   Note:
11404:   The blocksize of the matrix is used to determine the blocks on the diagonal of `C`

11406: .seealso: [](ch_matrices), `Mat`, `MatInvertBlockDiagonal()`
11407: @*/
11408: PetscErrorCode MatInvertBlockDiagonalMat(Mat A, Mat C)
11409: {
11410:   const PetscScalar *vals;
11411:   PetscInt          *dnnz;
11412:   PetscInt           m, rstart, rend, bs, i, j;

11414:   PetscFunctionBegin;
11415:   PetscCall(MatInvertBlockDiagonal(A, &vals));
11416:   PetscCall(MatGetBlockSize(A, &bs));
11417:   PetscCall(MatGetLocalSize(A, &m, NULL));
11418:   PetscCall(MatSetLayouts(C, A->rmap, A->cmap));
11419:   PetscCall(MatSetBlockSizes(C, A->rmap->bs, A->cmap->bs));
11420:   PetscCall(PetscMalloc1(m / bs, &dnnz));
11421:   for (j = 0; j < m / bs; j++) dnnz[j] = 1;
11422:   PetscCall(MatXAIJSetPreallocation(C, bs, dnnz, NULL, NULL, NULL));
11423:   PetscCall(PetscFree(dnnz));
11424:   PetscCall(MatGetOwnershipRange(C, &rstart, &rend));
11425:   PetscCall(MatSetOption(C, MAT_ROW_ORIENTED, PETSC_FALSE));
11426:   for (i = rstart / bs; i < rend / bs; i++) PetscCall(MatSetValuesBlocked(C, 1, &i, 1, &i, &vals[(i - rstart / bs) * bs * bs], INSERT_VALUES));
11427:   PetscCall(MatSetOption(C, MAT_NO_OFF_PROC_ENTRIES, PETSC_TRUE));
11428:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
11429:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
11430:   PetscCall(MatSetOption(C, MAT_NO_OFF_PROC_ENTRIES, PETSC_FALSE));
11431:   PetscCall(MatSetOption(C, MAT_ROW_ORIENTED, PETSC_TRUE));
11432:   PetscFunctionReturn(PETSC_SUCCESS);
11433: }

11435: /*@
11436:   MatTransposeColoringDestroy - Destroys a coloring context for matrix product $C = A B^T$ that was created
11437:   via `MatTransposeColoringCreate()`.

11439:   Collective

11441:   Input Parameter:
11442: . c - coloring context

11444:   Level: intermediate

11446: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringCreate()`
11447: @*/
11448: PetscErrorCode MatTransposeColoringDestroy(MatTransposeColoring *c)
11449: {
11450:   MatTransposeColoring matcolor = *c;

11452:   PetscFunctionBegin;
11453:   if (!matcolor) PetscFunctionReturn(PETSC_SUCCESS);
11454:   if (--((PetscObject)matcolor)->refct > 0) {
11455:     matcolor = NULL;
11456:     PetscFunctionReturn(PETSC_SUCCESS);
11457:   }

11459:   PetscCall(PetscFree3(matcolor->ncolumns, matcolor->nrows, matcolor->colorforrow));
11460:   PetscCall(PetscFree(matcolor->rows));
11461:   PetscCall(PetscFree(matcolor->den2sp));
11462:   PetscCall(PetscFree(matcolor->colorforcol));
11463:   PetscCall(PetscFree(matcolor->columns));
11464:   if (matcolor->brows > 0) PetscCall(PetscFree(matcolor->lstart));
11465:   PetscCall(PetscHeaderDestroy(c));
11466:   PetscFunctionReturn(PETSC_SUCCESS);
11467: }

11469: /*@
11470:   MatTransColoringApplySpToDen - Given a symbolic matrix product $C = A B^T$ for which
11471:   a `MatTransposeColoring` context has been created, computes a dense $B^T$ by applying
11472:   `MatTransposeColoring` to sparse `B`.

11474:   Collective

11476:   Input Parameters:
11477: + coloring - coloring context created with `MatTransposeColoringCreate()`
11478: - B        - sparse matrix

11480:   Output Parameter:
11481: . Btdense - dense matrix $B^T$

11483:   Level: developer

11485:   Note:
11486:   These are used internally for some implementations of `MatRARt()`

11488: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringCreate()`, `MatTransposeColoringDestroy()`, `MatTransColoringApplyDenToSp()`
11489: @*/
11490: PetscErrorCode MatTransColoringApplySpToDen(MatTransposeColoring coloring, Mat B, Mat Btdense)
11491: {
11492:   PetscFunctionBegin;

11497:   PetscCall((*B->ops->transcoloringapplysptoden)(coloring, B, Btdense));
11498:   PetscFunctionReturn(PETSC_SUCCESS);
11499: }

11501: /*@
11502:   MatTransColoringApplyDenToSp - Given a symbolic matrix product $C_{sp} = A B^T$ for which
11503:   a `MatTransposeColoring` context has been created and a dense matrix $C_{den} = A B^T_{dense}$
11504:   in which `B^T_{dens}` is obtained from `MatTransColoringApplySpToDen()`, recover sparse matrix
11505:   $C_{sp}$ from $C_{den}$.

11507:   Collective

11509:   Input Parameters:
11510: + matcoloring - coloring context created with `MatTransposeColoringCreate()`
11511: - Cden        - matrix product of a sparse matrix and a dense matrix Btdense

11513:   Output Parameter:
11514: . Csp - sparse matrix

11516:   Level: developer

11518:   Note:
11519:   These are used internally for some implementations of `MatRARt()`

11521: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringCreate()`, `MatTransposeColoringDestroy()`, `MatTransColoringApplySpToDen()`
11522: @*/
11523: PetscErrorCode MatTransColoringApplyDenToSp(MatTransposeColoring matcoloring, Mat Cden, Mat Csp)
11524: {
11525:   PetscFunctionBegin;

11530:   PetscCall((*Csp->ops->transcoloringapplydentosp)(matcoloring, Cden, Csp));
11531:   PetscCall(MatAssemblyBegin(Csp, MAT_FINAL_ASSEMBLY));
11532:   PetscCall(MatAssemblyEnd(Csp, MAT_FINAL_ASSEMBLY));
11533:   PetscFunctionReturn(PETSC_SUCCESS);
11534: }

11536: /*@
11537:   MatTransposeColoringCreate - Creates a matrix coloring context for the matrix product $C = A B^T$.

11539:   Collective

11541:   Input Parameters:
11542: + mat        - the matrix product C
11543: - iscoloring - the coloring of the matrix; usually obtained with `MatColoringCreate()` or `DMCreateColoring()`

11545:   Output Parameter:
11546: . color - the new coloring context

11548:   Level: intermediate

11550: .seealso: [](ch_matrices), `Mat`, `MatTransposeColoringDestroy()`, `MatTransColoringApplySpToDen()`,
11551:           `MatTransColoringApplyDenToSp()`
11552: @*/
11553: PetscErrorCode MatTransposeColoringCreate(Mat mat, ISColoring iscoloring, MatTransposeColoring *color)
11554: {
11555:   MatTransposeColoring c;
11556:   MPI_Comm             comm;

11558:   PetscFunctionBegin;
11559:   PetscAssertPointer(color, 3);

11561:   PetscCall(PetscLogEventBegin(MAT_TransposeColoringCreate, mat, 0, 0, 0));
11562:   PetscCall(PetscObjectGetComm((PetscObject)mat, &comm));
11563:   PetscCall(PetscHeaderCreate(c, MAT_TRANSPOSECOLORING_CLASSID, "MatTransposeColoring", "Matrix product C=A*B^T via coloring", "Mat", comm, MatTransposeColoringDestroy, NULL));
11564:   c->ctype = iscoloring->ctype;
11565:   PetscUseTypeMethod(mat, transposecoloringcreate, iscoloring, c);
11566:   *color = c;
11567:   PetscCall(PetscLogEventEnd(MAT_TransposeColoringCreate, mat, 0, 0, 0));
11568:   PetscFunctionReturn(PETSC_SUCCESS);
11569: }

11571: /*@
11572:   MatGetNonzeroState - Returns a 64-bit integer representing the current state of nonzeros in the matrix. If the
11573:   matrix has had new nonzero locations added to (or removed from) the matrix since the previous call, the value will be larger.

11575:   Not Collective

11577:   Input Parameter:
11578: . mat - the matrix

11580:   Output Parameter:
11581: . state - the current state

11583:   Level: intermediate

11585:   Notes:
11586:   You can only compare states from two different calls to the SAME matrix, you cannot compare calls between
11587:   different matrices

11589:   Use `PetscObjectStateGet()` to check for changes to the numerical values in a matrix

11591:   Use the result of `PetscObjectGetId()` to compare if a previously checked matrix is the same as the current matrix, do not compare object pointers.

11593: .seealso: [](ch_matrices), `Mat`, `PetscObjectStateGet()`, `PetscObjectGetId()`
11594: @*/
11595: PetscErrorCode MatGetNonzeroState(Mat mat, PetscObjectState *state)
11596: {
11597:   PetscFunctionBegin;
11599:   *state = mat->nonzerostate;
11600:   PetscFunctionReturn(PETSC_SUCCESS);
11601: }

11603: /*@
11604:   MatCreateMPIMatConcatenateSeqMat - Creates a single large PETSc matrix by concatenating sequential
11605:   matrices from each process

11607:   Collective

11609:   Input Parameters:
11610: + comm   - the communicators the parallel matrix will live on
11611: . seqmat - the input sequential matrices
11612: . n      - number of local columns (or `PETSC_DECIDE`)
11613: - reuse  - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`

11615:   Output Parameter:
11616: . mpimat - the parallel matrix generated

11618:   Level: developer

11620:   Note:
11621:   The number of columns of the matrix in EACH process MUST be the same.

11623: .seealso: [](ch_matrices), `Mat`
11624: @*/
11625: PetscErrorCode MatCreateMPIMatConcatenateSeqMat(MPI_Comm comm, Mat seqmat, PetscInt n, MatReuse reuse, Mat *mpimat)
11626: {
11627:   PetscMPIInt size;

11629:   PetscFunctionBegin;
11630:   PetscCallMPI(MPI_Comm_size(comm, &size));
11631:   if (size == 1) {
11632:     if (reuse == MAT_INITIAL_MATRIX) {
11633:       PetscCall(MatDuplicate(seqmat, MAT_COPY_VALUES, mpimat));
11634:     } else {
11635:       PetscCall(MatCopy(seqmat, *mpimat, SAME_NONZERO_PATTERN));
11636:     }
11637:     PetscFunctionReturn(PETSC_SUCCESS);
11638:   }

11640:   PetscCheck(reuse != MAT_REUSE_MATRIX || seqmat != *mpimat, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "MAT_REUSE_MATRIX means reuse the matrix passed in as the final argument, not the original matrix");

11642:   PetscCall(PetscLogEventBegin(MAT_Merge, seqmat, 0, 0, 0));
11643:   PetscCall((*seqmat->ops->creatempimatconcatenateseqmat)(comm, seqmat, n, reuse, mpimat));
11644:   PetscCall(PetscLogEventEnd(MAT_Merge, seqmat, 0, 0, 0));
11645:   PetscFunctionReturn(PETSC_SUCCESS);
11646: }

11648: /*@
11649:   MatSubdomainsCreateCoalesce - Creates index subdomains by coalescing adjacent MPI processes' ownership ranges.

11651:   Collective

11653:   Input Parameters:
11654: + A - the matrix to create subdomains from
11655: - N - requested number of subdomains

11657:   Output Parameters:
11658: + n   - number of subdomains resulting on this MPI process
11659: - iss - `IS` list with indices of subdomains on this MPI process

11661:   Level: advanced

11663:   Note:
11664:   The number of subdomains must be smaller than the communicator size

11666: .seealso: [](ch_matrices), `Mat`, `IS`
11667: @*/
11668: PetscErrorCode MatSubdomainsCreateCoalesce(Mat A, PetscInt N, PetscInt *n, IS *iss[])
11669: {
11670:   MPI_Comm    comm, subcomm;
11671:   PetscMPIInt size, rank, color;
11672:   PetscInt    rstart, rend, k;

11674:   PetscFunctionBegin;
11675:   PetscCall(PetscObjectGetComm((PetscObject)A, &comm));
11676:   PetscCallMPI(MPI_Comm_size(comm, &size));
11677:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
11678:   PetscCheck(N >= 1 && N < size, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "number of subdomains must be > 0 and < %d, got N = %" PetscInt_FMT, size, N);
11679:   *n    = 1;
11680:   k     = size / N + (size % N > 0); /* There are up to k ranks to a color */
11681:   color = rank / k;
11682:   PetscCallMPI(MPI_Comm_split(comm, color, rank, &subcomm));
11683:   PetscCall(PetscMalloc1(1, iss));
11684:   PetscCall(MatGetOwnershipRange(A, &rstart, &rend));
11685:   PetscCall(ISCreateStride(subcomm, rend - rstart, rstart, 1, iss[0]));
11686:   PetscCallMPI(MPI_Comm_free(&subcomm));
11687:   PetscFunctionReturn(PETSC_SUCCESS);
11688: }

11690: /*@
11691:   MatGalerkin - Constructs the coarse grid problem matrix via Galerkin projection.

11693:   If the interpolation and restriction operators are the same, uses `MatPtAP()`.
11694:   If they are not the same, uses `MatMatMatMult()`.

11696:   Once the coarse grid problem is constructed, correct for interpolation operators
11697:   that are not of full rank, which can legitimately happen in the case of non-nested
11698:   geometric multigrid.

11700:   Input Parameters:
11701: + restrct     - restriction operator
11702: . dA          - fine grid matrix
11703: . interpolate - interpolation operator
11704: . reuse       - either `MAT_INITIAL_MATRIX` or `MAT_REUSE_MATRIX`
11705: - fill        - expected fill, use `PETSC_DETERMINE` or `PETSC_DETERMINE` if you do not have a good estimate

11707:   Output Parameter:
11708: . A - the Galerkin coarse matrix

11710:   Options Database Key:
11711: . -pc_mg_galerkin (both|pmat|mat|none) - for what matrices the Galerkin process should be used

11713:   Level: developer

11715:   Note:
11716:   The deprecated `PETSC_DEFAULT` in `fill` also means use the current value

11718: .seealso: [](ch_matrices), `Mat`, `MatPtAP()`, `MatMatMatMult()`
11719: @*/
11720: PetscErrorCode MatGalerkin(Mat restrct, Mat dA, Mat interpolate, MatReuse reuse, PetscReal fill, Mat *A)
11721: {
11722:   IS  zerorows;
11723:   Vec diag;

11725:   PetscFunctionBegin;
11726:   PetscCheck(reuse != MAT_INPLACE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Inplace product not supported");
11727:   /* Construct the coarse grid matrix */
11728:   if (interpolate == restrct) {
11729:     PetscCall(MatPtAP(dA, interpolate, reuse, fill, A));
11730:   } else {
11731:     PetscCall(MatMatMatMult(restrct, dA, interpolate, reuse, fill, A));
11732:   }

11734:   /* If the interpolation matrix is not of full rank, A will have zero rows.
11735:      This can legitimately happen in the case of non-nested geometric multigrid.
11736:      In that event, we set the rows of the matrix to the rows of the identity,
11737:      ignoring the equations (as the RHS will also be zero). */

11739:   PetscCall(MatFindZeroRows(*A, &zerorows));

11741:   if (zerorows != NULL) { /* if there are any zero rows */
11742:     PetscCall(MatCreateVecs(*A, &diag, NULL));
11743:     PetscCall(MatGetDiagonal(*A, diag));
11744:     PetscCall(VecISSet(diag, zerorows, 1.0));
11745:     PetscCall(MatDiagonalSet(*A, diag, INSERT_VALUES));
11746:     PetscCall(VecDestroy(&diag));
11747:     PetscCall(ISDestroy(&zerorows));
11748:   }
11749:   PetscFunctionReturn(PETSC_SUCCESS);
11750: }

11752: /*@
11753:   MatSetOperation - Allows user to set a matrix operation for any matrix type

11755:   Logically Collective

11757:   Input Parameters:
11758: + mat - the matrix
11759: . op  - the name of the operation
11760: - f   - the function that provides the operation

11762:   Level: developer

11764:   Example Usage:
11765: .vb
11766:   extern PetscErrorCode usermult(Mat, Vec, Vec);

11768:   PetscCall(MatCreateXXX(comm, ..., &A));
11769:   PetscCall(MatSetOperation(A, MATOP_MULT, (PetscErrorCodeFn *)usermult));
11770: .ve

11772:   Notes:
11773:   See the file `include/petscmat.h` for a complete list of matrix
11774:   operations, which all have the form MATOP_<OPERATION>, where
11775:   <OPERATION> is the name (in all capital letters) of the
11776:   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).

11778:   All user-provided functions (except for `MATOP_DESTROY`) should have the same calling
11779:   sequence as the usual matrix interface routines, since they
11780:   are intended to be accessed via the usual matrix interface
11781:   routines, e.g.,
11782: .vb
11783:   MatMult(Mat, Vec, Vec) -> usermult(Mat, Vec, Vec)
11784: .ve

11786:   In particular each function MUST return `PETSC_SUCCESS` on success and
11787:   nonzero on failure.

11789:   This routine is distinct from `MatShellSetOperation()` in that it can be called on any matrix type.

11791: .seealso: [](ch_matrices), `Mat`, `MatGetOperation()`, `MatCreateShell()`, `MatShellSetContext()`, `MatShellSetOperation()`
11792: @*/
11793: PetscErrorCode MatSetOperation(Mat mat, MatOperation op, PetscErrorCodeFn *f)
11794: {
11795:   PetscFunctionBegin;
11798:   if (op == MATOP_VIEW && !mat->ops->viewnative && f != (PetscErrorCodeFn *)mat->ops->view) mat->ops->viewnative = mat->ops->view;
11799: #if !PetscDefined(USE_COMPLEX)
11800:   if (op == MATOP_MULT_HERMITIAN_TRANSPOSE) op = MATOP_MULT_TRANSPOSE;
11801:   else if (op == MATOP_MULT_HERMITIAN_TRANS_ADD) op = MATOP_MULT_TRANSPOSE_ADD;
11802:   else if (op == MATOP_HERMITIAN_TRANSPOSE) op = MATOP_TRANSPOSE;
11803: #endif
11804:   ((PetscErrorCodeFn **)mat->ops)[op] = f;
11805:   PetscFunctionReturn(PETSC_SUCCESS);
11806: }

11808: /*@
11809:   MatGetOperation - Gets a matrix operation for any matrix type.

11811:   Not Collective

11813:   Input Parameters:
11814: + mat - the matrix
11815: - op  - the name of the operation

11817:   Output Parameter:
11818: . f - the function that provides the operation

11820:   Level: developer

11822:   Example Usage:
11823: .vb
11824:   PetscErrorCode (*usermult)(Mat, Vec, Vec);

11826:   MatGetOperation(A, MATOP_MULT, (PetscErrorCodeFn **)&usermult);
11827: .ve

11829:   Notes:
11830:   See the file `include/petscmat.h` for a complete list of matrix
11831:   operations, which all have the form MATOP_<OPERATION>, where
11832:   <OPERATION> is the name (in all capital letters) of the
11833:   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).

11835:   This routine is distinct from `MatShellGetOperation()` in that it can be called on any matrix type.

11837: .seealso: [](ch_matrices), `Mat`, `MatSetOperation()`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`
11838: @*/
11839: PetscErrorCode MatGetOperation(Mat mat, MatOperation op, PetscErrorCodeFn **f)
11840: {
11841:   PetscFunctionBegin;
11843:   PetscAssertPointer(f, 3);
11844: #if !PetscDefined(USE_COMPLEX)
11845:   if (op == MATOP_MULT_HERMITIAN_TRANSPOSE) op = MATOP_MULT_TRANSPOSE;
11846:   else if (op == MATOP_MULT_HERMITIAN_TRANS_ADD) op = MATOP_MULT_TRANSPOSE_ADD;
11847:   else if (op == MATOP_HERMITIAN_TRANSPOSE) op = MATOP_TRANSPOSE;
11848: #endif
11849:   *f = ((PetscErrorCodeFn **)mat->ops)[op];
11850:   PetscFunctionReturn(PETSC_SUCCESS);
11851: }

11853: /*@
11854:   MatHasOperation - Determines whether the given matrix supports the particular operation.

11856:   Not Collective

11858:   Input Parameters:
11859: + mat - the matrix
11860: - op  - the operation, for example, `MATOP_GET_DIAGONAL`

11862:   Output Parameter:
11863: . has - either `PETSC_TRUE` or `PETSC_FALSE`

11865:   Level: advanced

11867:   Note:
11868:   See `MatSetOperation()` for additional discussion on naming convention and usage of `op`.

11870: .seealso: [](ch_matrices), `Mat`, `MatCreateShell()`, `MatGetOperation()`, `MatSetOperation()`
11871: @*/
11872: PetscErrorCode MatHasOperation(Mat mat, MatOperation op, PetscBool *has)
11873: {
11874:   PetscFunctionBegin;
11876:   PetscAssertPointer(has, 3);
11877: #if !PetscDefined(USE_COMPLEX)
11878:   if (op == MATOP_MULT_HERMITIAN_TRANSPOSE) op = MATOP_MULT_TRANSPOSE;
11879:   else if (op == MATOP_MULT_HERMITIAN_TRANS_ADD) op = MATOP_MULT_TRANSPOSE_ADD;
11880:   else if (op == MATOP_HERMITIAN_TRANSPOSE) op = MATOP_TRANSPOSE;
11881: #endif
11882:   if (op == MATOP_ADOT || op == MATOP_ANORM) {
11883:     /* MatADot() and MatANorm() fall back to MatMult() when the type has no method */
11884:     if (((void **)mat->ops)[op]) *has = PETSC_TRUE;
11885:     else PetscCall(MatHasOperation(mat, MATOP_MULT, has));
11886:     PetscFunctionReturn(PETSC_SUCCESS);
11887:   }
11888:   if (mat->ops->hasoperation) {
11889:     PetscUseTypeMethod(mat, hasoperation, op, has);
11890:   } else {
11891:     if (((void **)mat->ops)[op]) *has = PETSC_TRUE;
11892:     else {
11893:       *has = PETSC_FALSE;
11894:       if (op == MATOP_CREATE_SUBMATRIX) {
11895:         PetscMPIInt size;

11897:         PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &size));
11898:         if (size == 1) PetscCall(MatHasOperation(mat, MATOP_CREATE_SUBMATRICES, has));
11899:       }
11900:     }
11901:   }
11902:   PetscFunctionReturn(PETSC_SUCCESS);
11903: }

11905: /*@
11906:   MatHasCongruentLayouts - Determines whether the rows and columns layouts of the matrix are congruent

11908:   Collective

11910:   Input Parameter:
11911: . mat - the matrix

11913:   Output Parameter:
11914: . cong - either `PETSC_TRUE` or `PETSC_FALSE`

11916:   Level: beginner

11918: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatSetSizes()`, `PetscLayout`
11919: @*/
11920: PetscErrorCode MatHasCongruentLayouts(Mat mat, PetscBool *cong)
11921: {
11922:   PetscFunctionBegin;
11925:   PetscAssertPointer(cong, 2);
11926:   if (!mat->rmap || !mat->cmap) {
11927:     *cong = mat->rmap == mat->cmap ? PETSC_TRUE : PETSC_FALSE;
11928:     PetscFunctionReturn(PETSC_SUCCESS);
11929:   }
11930:   if (mat->congruentlayouts == PETSC_DECIDE) { /* first time we compare rows and cols layouts */
11931:     PetscCall(PetscLayoutSetUp(mat->rmap));
11932:     PetscCall(PetscLayoutSetUp(mat->cmap));
11933:     PetscCall(PetscLayoutCompare(mat->rmap, mat->cmap, cong));
11934:     if (*cong) mat->congruentlayouts = 1;
11935:     else mat->congruentlayouts = 0;
11936:   } else *cong = mat->congruentlayouts ? PETSC_TRUE : PETSC_FALSE;
11937:   PetscFunctionReturn(PETSC_SUCCESS);
11938: }

11940: /*@
11941:   MatFlag - set infinity into the local part of the matrix on any subset of MPI processes

11943:   Logically Collective

11945:   Input Parameters:
11946: + A   - the matrix, can be `NULL` but only if on all processes
11947: - flg - indicates if this processes portion of the matrix should be set to infinity

11949:   Level: developer

11951:   Notes:
11952:   This is used to flag a block of solutions that a linear solver failed to compute, as `VecFlag()` does for a single solution.

11954:   The state of `A` is increased on all processes, whether or not their portion is flagged, so an outer solver that tracks it detects the failure even when the entries were already infinite.

11956:   Only the dense types (`MATSEQDENSE`, `MATMPIDENSE`, and their device variants) currently implement this operation.

11958: .seealso: [](ch_matrices), `Mat`, `VecFlag()`, `MatZeroEntries()`, `MatSetValues()`
11959: @*/
11960: PetscErrorCode MatFlag(Mat A, PetscInt flg)
11961: {
11962:   PetscFunctionBegin;
11963:   if (!A) PetscFunctionReturn(PETSC_SUCCESS);
11966:   MatCheckPreallocated(A, 1);
11967:   PetscCall(PetscObjectStateIncrease((PetscObject)A));
11968:   if (flg) PetscUseTypeMethod(A, setinf);
11969:   PetscFunctionReturn(PETSC_SUCCESS);
11970: }

11972: /*@
11973:   MatCreateGraph - create a scalar matrix (that is a matrix with one vertex for each block vertex in the original matrix), for use in graph algorithms
11974:   and possibly removes small values from the graph structure.

11976:   Collective

11978:   Input Parameters:
11979: + A       - the matrix
11980: . sym     - `PETSC_TRUE` indicates that the graph should be symmetrized
11981: . scale   - `PETSC_TRUE` indicates that the graph edge weights should be symmetrically scaled with the diagonal entry
11982: . filter  - filter value - < 0: does nothing; == 0: removes only 0.0 entries; otherwise: removes entries with $|entries| \le filter$
11983: . num_idx - size of `index` array
11984: - index   - array of block indices to use for graph strength of connection weight

11986:   Output Parameter:
11987: . graph - the resulting graph

11989:   Level: advanced

11991: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `PCGAMG`
11992: @*/
11993: PetscErrorCode MatCreateGraph(Mat A, PetscBool sym, PetscBool scale, PetscReal filter, PetscInt num_idx, PetscInt index[], Mat *graph)
11994: {
11995:   PetscFunctionBegin;
11999:   PetscAssertPointer(graph, 7);
12000:   PetscCall(PetscLogEventBegin(MAT_CreateGraph, A, 0, 0, 0));
12001:   PetscUseTypeMethod(A, creategraph, sym, scale, filter, num_idx, index, graph);
12002:   PetscCall(PetscLogEventEnd(MAT_CreateGraph, A, 0, 0, 0));
12003:   PetscFunctionReturn(PETSC_SUCCESS);
12004: }

12006: /*@
12007:   MatEliminateZeros - eliminate the nondiagonal zero entries in place from the nonzero structure of a sparse `Mat` in place,
12008:   meaning the same memory is used for the matrix, and no new memory is allocated.

12010:   Collective

12012:   Input Parameters:
12013: + A    - the matrix
12014: - keep - if for a given row of `A`, the diagonal coefficient is zero, indicates whether it should be left in the structure or eliminated as well

12016:   Level: intermediate

12018:   Developer Note:
12019:   The entries in the sparse matrix data structure are shifted to fill in the unneeded locations in the data. Thus the end
12020:   of the arrays in the data structure may be no longer needed to represent the matrix.

12022: .seealso: [](ch_matrices), `Mat`, `MatCreate()`, `MatCreateGraph()`, `MatFilter()`
12023: @*/
12024: PetscErrorCode MatEliminateZeros(Mat A, PetscBool keep)
12025: {
12026:   PetscFunctionBegin;
12028:   PetscUseTypeMethod(A, eliminatezeros, keep);
12029:   PetscFunctionReturn(PETSC_SUCCESS);
12030: }

12032: /*@
12033:   MatGetCurrentMemType - Get the memory location of the matrix

12035:   Not Collective, but the result will be the same on all MPI processes

12037:   Input Parameter:
12038: . A - the matrix whose memory type we are checking

12040:   Output Parameter:
12041: . m - the memory type, see `PetscMemType`

12043:   Level: intermediate

12045: .seealso: [](ch_matrices), `Mat`, `MatBoundToCPU()`, `PetscMemType`
12046: @*/
12047: PetscErrorCode MatGetCurrentMemType(Mat A, PetscMemType *m)
12048: {
12049:   PetscFunctionBegin;
12051:   PetscAssertPointer(m, 2);
12052:   if (A->ops->getcurrentmemtype) PetscUseTypeMethod(A, getcurrentmemtype, m);
12053:   else *m = PETSC_MEMTYPE_HOST;
12054:   PetscFunctionReturn(PETSC_SUCCESS);
12055: }