Actual source code: matnest.c

  1: #include <../src/mat/impls/nest/matnestimpl.h>
  2: #include <../src/mat/impls/aij/seq/aij.h>
  3: #include <../src/mat/impls/shell/shell.h>
  4: #include <petscsf.h>

  6: static PetscErrorCode MatSetUp_NestIS_Private(Mat, PetscInt, const IS[], PetscInt, const IS[]);
  7: static PetscErrorCode MatCreateVecs_Nest(Mat, Vec *, Vec *);
  8: static PetscErrorCode MatReset_Nest(Mat);

 10: PETSC_INTERN PetscErrorCode MatConvert_Nest_IS(Mat, MatType, MatReuse, Mat *);

 12: /* private functions */
 13: static PetscErrorCode MatNestGetSizes_Private(Mat A, PetscInt *m, PetscInt *n, PetscInt *M, PetscInt *N)
 14: {
 15:   Mat_Nest *bA = (Mat_Nest *)A->data;
 16:   PetscInt  i, j;

 18:   PetscFunctionBegin;
 19:   *m = *n = *M = *N = 0;
 20:   for (i = 0; i < bA->nr; i++) { /* rows */
 21:     PetscInt sm, sM;
 22:     PetscCall(ISGetLocalSize(bA->isglobal.row[i], &sm));
 23:     PetscCall(ISGetSize(bA->isglobal.row[i], &sM));
 24:     *m += sm;
 25:     *M += sM;
 26:   }
 27:   for (j = 0; j < bA->nc; j++) { /* cols */
 28:     PetscInt sn, sN;
 29:     PetscCall(ISGetLocalSize(bA->isglobal.col[j], &sn));
 30:     PetscCall(ISGetSize(bA->isglobal.col[j], &sN));
 31:     *n += sn;
 32:     *N += sN;
 33:   }
 34:   PetscFunctionReturn(PETSC_SUCCESS);
 35: }

 37: /* operations */
 38: static PetscErrorCode MatMult_Nest(Mat A, Vec x, Vec y)
 39: {
 40:   Mat_Nest *bA = (Mat_Nest *)A->data;
 41:   Vec      *bx = bA->right, *by = bA->left;
 42:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

 44:   PetscFunctionBegin;
 45:   for (i = 0; i < nr; i++) PetscCall(VecGetSubVector(y, bA->isglobal.row[i], &by[i]));
 46:   for (i = 0; i < nc; i++) PetscCall(VecGetSubVector(x, bA->isglobal.col[i], &bx[i]));
 47:   for (i = 0; i < nr; i++) {
 48:     PetscCall(VecZeroEntries(by[i]));
 49:     for (j = 0; j < nc; j++) {
 50:       if (!bA->m[i][j]) continue;
 51:       /* y[i] <- y[i] + A[i][j] * x[j] */
 52:       PetscCall(MatMultAdd(bA->m[i][j], bx[j], by[i], by[i]));
 53:     }
 54:   }
 55:   for (i = 0; i < nr; i++) PetscCall(VecRestoreSubVector(y, bA->isglobal.row[i], &by[i]));
 56:   for (i = 0; i < nc; i++) PetscCall(VecRestoreSubVector(x, bA->isglobal.col[i], &bx[i]));
 57:   PetscFunctionReturn(PETSC_SUCCESS);
 58: }

 60: static PetscErrorCode MatMultAdd_Nest(Mat A, Vec x, Vec y, Vec z)
 61: {
 62:   Mat_Nest *bA = (Mat_Nest *)A->data;
 63:   Vec      *bx = bA->right, *bz = bA->left;
 64:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

 66:   PetscFunctionBegin;
 67:   for (i = 0; i < nr; i++) PetscCall(VecGetSubVector(z, bA->isglobal.row[i], &bz[i]));
 68:   for (i = 0; i < nc; i++) PetscCall(VecGetSubVector(x, bA->isglobal.col[i], &bx[i]));
 69:   for (i = 0; i < nr; i++) {
 70:     if (y != z) {
 71:       Vec by;
 72:       PetscCall(VecGetSubVector(y, bA->isglobal.row[i], &by));
 73:       PetscCall(VecCopy(by, bz[i]));
 74:       PetscCall(VecRestoreSubVector(y, bA->isglobal.row[i], &by));
 75:     }
 76:     for (j = 0; j < nc; j++) {
 77:       if (!bA->m[i][j]) continue;
 78:       /* y[i] <- y[i] + A[i][j] * x[j] */
 79:       PetscCall(MatMultAdd(bA->m[i][j], bx[j], bz[i], bz[i]));
 80:     }
 81:   }
 82:   for (i = 0; i < nr; i++) PetscCall(VecRestoreSubVector(z, bA->isglobal.row[i], &bz[i]));
 83:   for (i = 0; i < nc; i++) PetscCall(VecRestoreSubVector(x, bA->isglobal.col[i], &bx[i]));
 84:   PetscFunctionReturn(PETSC_SUCCESS);
 85: }

 87: typedef struct {
 88:   Mat         *workC;      /* array of Mat with specific containers depending on the underlying MatMatMult implementation */
 89:   PetscScalar *tarray;     /* buffer for storing all temporary products A[i][j] B[j] */
 90:   PetscInt    *dm, *dn, k; /* displacements and number of submatrices */
 91: } Nest_Dense;

 93: static PetscErrorCode MatProductNumeric_Nest_Dense(Mat C)
 94: {
 95:   Mat_Nest          *bA;
 96:   Nest_Dense        *contents;
 97:   Mat                viewB, viewC, productB, workC;
 98:   const PetscScalar *barray;
 99:   PetscScalar       *carray;
100:   PetscInt           i, j, M, N, nr, nc, ldb, ldc;
101:   Mat                A, B;

103:   PetscFunctionBegin;
104:   MatCheckProduct(C, 1);
105:   A = C->product->A;
106:   B = C->product->B;
107:   PetscCall(MatGetSize(B, NULL, &N));
108:   if (!N) {
109:     PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
110:     PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
111:     PetscFunctionReturn(PETSC_SUCCESS);
112:   }
113:   contents = (Nest_Dense *)C->product->data;
114:   PetscCheck(contents, PetscObjectComm((PetscObject)C), PETSC_ERR_PLIB, "Product data empty");
115:   bA = (Mat_Nest *)A->data;
116:   nr = bA->nr;
117:   nc = bA->nc;
118:   PetscCall(MatDenseGetLDA(B, &ldb));
119:   PetscCall(MatDenseGetLDA(C, &ldc));
120:   PetscCall(MatZeroEntries(C));
121:   PetscCall(MatDenseGetArrayRead(B, &barray));
122:   PetscCall(MatDenseGetArray(C, &carray));
123:   for (i = 0; i < nr; i++) {
124:     PetscCall(ISGetSize(bA->isglobal.row[i], &M));
125:     PetscCall(MatCreateDense(PetscObjectComm((PetscObject)A), contents->dm[i + 1] - contents->dm[i], PETSC_DECIDE, M, N, PetscSafePointerPlusOffset(carray, contents->dm[i]), &viewC));
126:     PetscCall(MatDenseSetLDA(viewC, ldc));
127:     for (j = 0; j < nc; j++) {
128:       if (!bA->m[i][j]) continue;
129:       PetscCall(ISGetSize(bA->isglobal.col[j], &M));
130:       PetscCall(MatCreateDense(PetscObjectComm((PetscObject)A), contents->dn[j + 1] - contents->dn[j], PETSC_DECIDE, M, N, PetscSafePointerPlusOffset((PetscScalar *)barray, contents->dn[j]), &viewB));
131:       PetscCall(MatDenseSetLDA(viewB, ldb));

133:       /* MatMatMultNumeric(bA->m[i][j],viewB,contents->workC[i*nc + j]); */
134:       workC             = contents->workC[i * nc + j];
135:       productB          = workC->product->B;
136:       workC->product->B = viewB; /* use newly created dense matrix viewB */
137:       PetscCall(MatProductNumeric(workC));
138:       PetscCall(MatDestroy(&viewB));
139:       workC->product->B = productB; /* resume original B */

141:       /* C[i] <- workC + C[i] */
142:       PetscCall(MatAXPY(viewC, 1.0, contents->workC[i * nc + j], SAME_NONZERO_PATTERN));
143:     }
144:     PetscCall(MatDestroy(&viewC));
145:   }
146:   PetscCall(MatDenseRestoreArray(C, &carray));
147:   PetscCall(MatDenseRestoreArrayRead(B, &barray));

149:   PetscCall(MatSetOption(C, MAT_NO_OFF_PROC_ENTRIES, PETSC_TRUE));
150:   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
151:   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
152:   PetscFunctionReturn(PETSC_SUCCESS);
153: }

155: static PetscErrorCode MatNest_DenseDestroy(PetscCtxRt ctx)
156: {
157:   Nest_Dense *contents = *(Nest_Dense **)ctx;
158:   PetscInt    i;

160:   PetscFunctionBegin;
161:   PetscCall(PetscFree(contents->tarray));
162:   for (i = 0; i < contents->k; i++) PetscCall(MatDestroy(contents->workC + i));
163:   PetscCall(PetscFree3(contents->dm, contents->dn, contents->workC));
164:   PetscCall(PetscFree(contents));
165:   PetscFunctionReturn(PETSC_SUCCESS);
166: }

168: static PetscErrorCode MatProductSymbolic_Nest_Dense(Mat C)
169: {
170:   Mat_Nest          *bA;
171:   Mat                viewB, workC;
172:   const PetscScalar *barray;
173:   PetscInt           i, j, M, N, m, n, nr, nc, maxm = 0, ldb;
174:   Nest_Dense        *contents = NULL;
175:   PetscBool          cisdense;
176:   Mat                A, B;
177:   PetscReal          fill;

179:   PetscFunctionBegin;
180:   MatCheckProduct(C, 1);
181:   PetscCheck(!C->product->data, PetscObjectComm((PetscObject)C), PETSC_ERR_PLIB, "Product data not empty");
182:   A    = C->product->A;
183:   B    = C->product->B;
184:   fill = C->product->fill;
185:   bA   = (Mat_Nest *)A->data;
186:   nr   = bA->nr;
187:   nc   = bA->nc;
188:   PetscCall(MatGetLocalSize(C, &m, &n));
189:   PetscCall(MatGetSize(C, &M, &N));
190:   if (m == PETSC_DECIDE || n == PETSC_DECIDE || M == PETSC_DECIDE || N == PETSC_DECIDE) {
191:     PetscCall(MatGetLocalSize(B, NULL, &n));
192:     PetscCall(MatGetSize(B, NULL, &N));
193:     PetscCall(MatGetLocalSize(A, &m, NULL));
194:     PetscCall(MatGetSize(A, &M, NULL));
195:     PetscCall(MatSetSizes(C, m, n, M, N));
196:   }
197:   PetscCall(PetscObjectTypeCompareAny((PetscObject)C, &cisdense, MATSEQDENSE, MATMPIDENSE, MATSEQDENSECUDA, MATMPIDENSECUDA, ""));
198:   if (!cisdense) PetscCall(MatSetType(C, ((PetscObject)B)->type_name));
199:   PetscCall(MatSetUp(C));
200:   if (!N) {
201:     C->ops->productnumeric = MatProductNumeric_Nest_Dense;
202:     PetscFunctionReturn(PETSC_SUCCESS);
203:   }

205:   PetscCall(PetscNew(&contents));
206:   C->product->data    = contents;
207:   C->product->destroy = MatNest_DenseDestroy;
208:   PetscCall(PetscCalloc3(nr + 1, &contents->dm, nc + 1, &contents->dn, nr * nc, &contents->workC));
209:   contents->k = nr * nc;
210:   for (i = 0; i < nr; i++) {
211:     PetscCall(ISGetLocalSize(bA->isglobal.row[i], contents->dm + i + 1));
212:     maxm = PetscMax(maxm, contents->dm[i + 1]);
213:     contents->dm[i + 1] += contents->dm[i];
214:   }
215:   for (i = 0; i < nc; i++) {
216:     PetscCall(ISGetLocalSize(bA->isglobal.col[i], contents->dn + i + 1));
217:     contents->dn[i + 1] += contents->dn[i];
218:   }
219:   PetscCall(PetscMalloc1(maxm * N, &contents->tarray));
220:   PetscCall(MatDenseGetLDA(B, &ldb));
221:   PetscCall(MatGetSize(B, NULL, &N));
222:   PetscCall(MatDenseGetArrayRead(B, &barray));
223:   /* loops are permuted compared to MatMatMultNumeric so that viewB is created only once per column of A */
224:   for (j = 0; j < nc; j++) {
225:     PetscCall(ISGetSize(bA->isglobal.col[j], &M));
226:     PetscCall(MatCreateDense(PetscObjectComm((PetscObject)A), contents->dn[j + 1] - contents->dn[j], PETSC_DECIDE, M, N, PetscSafePointerPlusOffset((PetscScalar *)barray, contents->dn[j]), &viewB));
227:     PetscCall(MatDenseSetLDA(viewB, ldb));
228:     for (i = 0; i < nr; i++) {
229:       if (!bA->m[i][j]) continue;
230:       /* MatMatMultSymbolic may attach a specific container (depending on MatType of bA->m[i][j]) to workC[i][j] */

232:       PetscCall(MatProductCreate(bA->m[i][j], viewB, NULL, &contents->workC[i * nc + j]));
233:       workC = contents->workC[i * nc + j];
234:       PetscCall(MatProductSetType(workC, MATPRODUCT_AB));
235:       PetscCall(MatProductSetAlgorithm(workC, "default"));
236:       PetscCall(MatProductSetFill(workC, fill));
237:       PetscCall(MatProductSetFromOptions(workC));
238:       PetscCall(MatProductSymbolic(workC));

240:       /* since tarray will be shared by all Mat */
241:       PetscCall(MatSeqDenseSetPreallocation(workC, contents->tarray));
242:       PetscCall(MatMPIDenseSetPreallocation(workC, contents->tarray));
243:     }
244:     PetscCall(MatDestroy(&viewB));
245:   }
246:   PetscCall(MatDenseRestoreArrayRead(B, &barray));

248:   C->ops->productnumeric = MatProductNumeric_Nest_Dense;
249:   PetscFunctionReturn(PETSC_SUCCESS);
250: }

252: static PetscErrorCode MatProductSetFromOptions_Nest_Dense(Mat C)
253: {
254:   Mat_Product *product = C->product;

256:   PetscFunctionBegin;
257:   if (product->type == MATPRODUCT_AB) C->ops->productsymbolic = MatProductSymbolic_Nest_Dense;
258:   PetscFunctionReturn(PETSC_SUCCESS);
259: }

261: static PetscErrorCode MatMultTransposeKernel_Nest(Mat A, Vec x, Vec y, PetscBool herm)
262: {
263:   Mat_Nest *bA = (Mat_Nest *)A->data;
264:   Vec      *bx = bA->left, *by = bA->right;
265:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

267:   PetscFunctionBegin;
268:   for (i = 0; i < nr; i++) PetscCall(VecGetSubVector(x, bA->isglobal.row[i], &bx[i]));
269:   for (i = 0; i < nc; i++) PetscCall(VecGetSubVector(y, bA->isglobal.col[i], &by[i]));
270:   for (j = 0; j < nc; j++) {
271:     PetscCall(VecZeroEntries(by[j]));
272:     for (i = 0; i < nr; i++) {
273:       if (!bA->m[i][j]) continue;
274:       if (herm) PetscCall(MatMultHermitianTransposeAdd(bA->m[i][j], bx[i], by[j], by[j])); /* y[j] <- y[j] + (A[i][j])^H * x[i] */
275:       else PetscCall(MatMultTransposeAdd(bA->m[i][j], bx[i], by[j], by[j]));               /* y[j] <- y[j] + (A[i][j])^T * x[i] */
276:     }
277:   }
278:   for (i = 0; i < nr; i++) PetscCall(VecRestoreSubVector(x, bA->isglobal.row[i], &bx[i]));
279:   for (i = 0; i < nc; i++) PetscCall(VecRestoreSubVector(y, bA->isglobal.col[i], &by[i]));
280:   PetscFunctionReturn(PETSC_SUCCESS);
281: }

283: static PetscErrorCode MatMultTranspose_Nest(Mat A, Vec x, Vec y)
284: {
285:   PetscFunctionBegin;
286:   PetscCall(MatMultTransposeKernel_Nest(A, x, y, PETSC_FALSE));
287:   PetscFunctionReturn(PETSC_SUCCESS);
288: }

290: static PetscErrorCode MatMultHermitianTranspose_Nest(Mat A, Vec x, Vec y)
291: {
292:   PetscFunctionBegin;
293:   PetscCall(MatMultTransposeKernel_Nest(A, x, y, PETSC_TRUE));
294:   PetscFunctionReturn(PETSC_SUCCESS);
295: }

297: static PetscErrorCode MatMultTransposeAddKernel_Nest(Mat A, Vec x, Vec y, Vec z, PetscBool herm)
298: {
299:   Mat_Nest *bA = (Mat_Nest *)A->data;
300:   Vec      *bx = bA->left, *bz = bA->right;
301:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

303:   PetscFunctionBegin;
304:   for (i = 0; i < nr; i++) PetscCall(VecGetSubVector(x, bA->isglobal.row[i], &bx[i]));
305:   for (i = 0; i < nc; i++) PetscCall(VecGetSubVector(z, bA->isglobal.col[i], &bz[i]));
306:   for (j = 0; j < nc; j++) {
307:     if (y != z) {
308:       Vec by;
309:       PetscCall(VecGetSubVector(y, bA->isglobal.col[j], &by));
310:       PetscCall(VecCopy(by, bz[j]));
311:       PetscCall(VecRestoreSubVector(y, bA->isglobal.col[j], &by));
312:     }
313:     for (i = 0; i < nr; i++) {
314:       if (!bA->m[i][j]) continue;
315:       if (herm) PetscCall(MatMultHermitianTransposeAdd(bA->m[i][j], bx[i], bz[j], bz[j])); /* z[j] <- y[j] + (A[i][j])^H * x[i] */
316:       else PetscCall(MatMultTransposeAdd(bA->m[i][j], bx[i], bz[j], bz[j]));               /* z[j] <- y[j] + (A[i][j])^T * x[i] */
317:     }
318:   }
319:   for (i = 0; i < nr; i++) PetscCall(VecRestoreSubVector(x, bA->isglobal.row[i], &bx[i]));
320:   for (i = 0; i < nc; i++) PetscCall(VecRestoreSubVector(z, bA->isglobal.col[i], &bz[i]));
321:   PetscFunctionReturn(PETSC_SUCCESS);
322: }

324: static PetscErrorCode MatMultTransposeAdd_Nest(Mat A, Vec x, Vec y, Vec z)
325: {
326:   PetscFunctionBegin;
327:   PetscCall(MatMultTransposeAddKernel_Nest(A, x, y, z, PETSC_FALSE));
328:   PetscFunctionReturn(PETSC_SUCCESS);
329: }

331: static PetscErrorCode MatMultHermitianTransposeAdd_Nest(Mat A, Vec x, Vec y, Vec z)
332: {
333:   PetscFunctionBegin;
334:   PetscCall(MatMultTransposeAddKernel_Nest(A, x, y, z, PETSC_TRUE));
335:   PetscFunctionReturn(PETSC_SUCCESS);
336: }

338: static PetscErrorCode MatTranspose_Nest(Mat A, MatReuse reuse, Mat *B)
339: {
340:   Mat_Nest *bA = (Mat_Nest *)A->data, *bC;
341:   Mat       C;
342:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

344:   PetscFunctionBegin;
345:   if (reuse == MAT_REUSE_MATRIX) PetscCall(MatTransposeCheckNonzeroState_Private(A, *B));
346:   PetscCheck(reuse != MAT_INPLACE_MATRIX || nr == nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_SIZ, "Square nested matrix only for in-place");

348:   if (reuse == MAT_INITIAL_MATRIX || reuse == MAT_INPLACE_MATRIX) {
349:     Mat *subs;
350:     IS  *is_row, *is_col;

352:     PetscCall(PetscCalloc1(nr * nc, &subs));
353:     PetscCall(PetscMalloc2(nr, &is_row, nc, &is_col));
354:     PetscCall(MatNestGetISs(A, is_row, is_col));
355:     if (reuse == MAT_INPLACE_MATRIX) {
356:       for (i = 0; i < nr; i++) {
357:         for (j = 0; j < nc; j++) subs[i + nr * j] = bA->m[i][j];
358:       }
359:     }

361:     PetscCall(MatCreateNest(PetscObjectComm((PetscObject)A), nc, is_col, nr, is_row, subs, &C));
362:     PetscCall(PetscFree(subs));
363:     PetscCall(PetscFree2(is_row, is_col));
364:   } else {
365:     C = *B;
366:   }

368:   bC = (Mat_Nest *)C->data;
369:   for (i = 0; i < nr; i++) {
370:     for (j = 0; j < nc; j++) {
371:       if (bA->m[i][j]) {
372:         PetscCall(MatTranspose(bA->m[i][j], reuse, &bC->m[j][i]));
373:       } else {
374:         bC->m[j][i] = NULL;
375:       }
376:     }
377:   }

379:   if (reuse == MAT_INITIAL_MATRIX || reuse == MAT_REUSE_MATRIX) {
380:     *B = C;
381:   } else {
382:     PetscCall(MatHeaderMerge(A, &C));
383:   }
384:   PetscFunctionReturn(PETSC_SUCCESS);
385: }

387: static PetscErrorCode MatNestDestroyISList(PetscInt n, IS **list)
388: {
389:   IS      *lst = *list;
390:   PetscInt i;

392:   PetscFunctionBegin;
393:   if (!lst) PetscFunctionReturn(PETSC_SUCCESS);
394:   for (i = 0; i < n; i++) PetscCall(ISDestroy(&lst[i]));
395:   PetscCall(PetscFree(lst));
396:   *list = NULL;
397:   PetscFunctionReturn(PETSC_SUCCESS);
398: }

400: static PetscErrorCode MatReset_Nest(Mat A)
401: {
402:   Mat_Nest *vs = (Mat_Nest *)A->data;
403:   PetscInt  i, j;

405:   PetscFunctionBegin;
406:   /* release the matrices and the place holders */
407:   PetscCall(MatNestDestroyISList(vs->nr, &vs->isglobal.row));
408:   PetscCall(MatNestDestroyISList(vs->nc, &vs->isglobal.col));
409:   PetscCall(MatNestDestroyISList(vs->nr, &vs->islocal.row));
410:   PetscCall(MatNestDestroyISList(vs->nc, &vs->islocal.col));

412:   PetscCall(PetscFree(vs->row_len));
413:   PetscCall(PetscFree(vs->col_len));
414:   PetscCall(PetscFree(vs->nnzstate));

416:   PetscCall(PetscFree2(vs->left, vs->right));

418:   /* release the matrices and the place holders */
419:   if (vs->m) {
420:     for (i = 0; i < vs->nr; i++) {
421:       for (j = 0; j < vs->nc; j++) PetscCall(MatDestroy(&vs->m[i][j]));
422:     }
423:     PetscCall(PetscFree(vs->m[0]));
424:     PetscCall(PetscFree(vs->m));
425:   }

427:   /* restore defaults */
428:   vs->nr            = 0;
429:   vs->nc            = 0;
430:   vs->splitassembly = PETSC_FALSE;
431:   PetscFunctionReturn(PETSC_SUCCESS);
432: }

434: static PetscErrorCode MatDestroy_Nest(Mat A)
435: {
436:   PetscFunctionBegin;
437:   PetscCall(MatReset_Nest(A));
438:   PetscCall(PetscFree(A->data));
439:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMat_C", NULL));
440:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMat_C", NULL));
441:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMats_C", NULL));
442:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSize_C", NULL));
443:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetISs_C", NULL));
444:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetLocalISs_C", NULL));
445:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetVecType_C", NULL));
446:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMats_C", NULL));
447:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpiaij_C", NULL));
448:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqaij_C", NULL));
449:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_aij_C", NULL));
450:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_is_C", NULL));
451:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpidense_C", NULL));
452:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqdense_C", NULL));
453:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_seqdense_C", NULL));
454:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_mpidense_C", NULL));
455:   PetscFunctionReturn(PETSC_SUCCESS);
456: }

458: static PetscErrorCode MatAssemblyBegin_Nest(Mat A, MatAssemblyType type)
459: {
460:   Mat_Nest *vs = (Mat_Nest *)A->data;
461:   PetscInt  i, j;
462:   PetscBool nnzstate = PETSC_FALSE;

464:   PetscFunctionBegin;
465:   for (i = 0; i < vs->nr; i++) {
466:     for (j = 0; j < vs->nc; j++) {
467:       PetscObjectState subnnzstate = 0;
468:       if (vs->m[i][j]) {
469:         PetscCall(MatAssemblyBegin(vs->m[i][j], type));
470:         if (!vs->splitassembly) {
471:           /* Note: split assembly will fail if the same block appears more than once (even indirectly through a nested
472:            * sub-block). This could be fixed by adding a flag to Mat so that there was a way to check if a Mat was
473:            * already performing an assembly, but the result would by more complicated and appears to offer less
474:            * potential for diagnostics and correctness checking. Split assembly should be fixed once there is an
475:            * interface for libraries to make asynchronous progress in "user-defined non-blocking collectives".
476:            */
477:           PetscCall(MatAssemblyEnd(vs->m[i][j], type));
478:           PetscCall(MatGetNonzeroState(vs->m[i][j], &subnnzstate));
479:         }
480:       }
481:       nnzstate                     = (PetscBool)(nnzstate || vs->nnzstate[i * vs->nc + j] != subnnzstate);
482:       vs->nnzstate[i * vs->nc + j] = subnnzstate;
483:     }
484:   }
485:   if (nnzstate) A->nonzerostate++;
486:   PetscFunctionReturn(PETSC_SUCCESS);
487: }

489: static PetscErrorCode MatAssemblyEnd_Nest(Mat A, MatAssemblyType type)
490: {
491:   Mat_Nest *vs = (Mat_Nest *)A->data;
492:   PetscInt  i, j;

494:   PetscFunctionBegin;
495:   for (i = 0; i < vs->nr; i++) {
496:     for (j = 0; j < vs->nc; j++) {
497:       if (vs->m[i][j]) {
498:         if (vs->splitassembly) PetscCall(MatAssemblyEnd(vs->m[i][j], type));
499:       }
500:     }
501:   }
502:   PetscFunctionReturn(PETSC_SUCCESS);
503: }

505: static PetscErrorCode MatNestFindNonzeroSubMatRow(Mat A, PetscInt row, Mat *B)
506: {
507:   Mat_Nest *vs = (Mat_Nest *)A->data;
508:   PetscInt  j;
509:   Mat       sub;

511:   PetscFunctionBegin;
512:   sub = (row < vs->nc) ? vs->m[row][row] : (Mat)NULL; /* Prefer to find on the diagonal */
513:   for (j = 0; !sub && j < vs->nc; j++) sub = vs->m[row][j];
514:   if (sub) PetscCall(MatSetUp(sub)); /* Ensure that the sizes are available */
515:   *B = sub;
516:   PetscFunctionReturn(PETSC_SUCCESS);
517: }

519: static PetscErrorCode MatNestFindNonzeroSubMatCol(Mat A, PetscInt col, Mat *B)
520: {
521:   Mat_Nest *vs = (Mat_Nest *)A->data;
522:   PetscInt  i;
523:   Mat       sub;

525:   PetscFunctionBegin;
526:   sub = (col < vs->nr) ? vs->m[col][col] : (Mat)NULL; /* Prefer to find on the diagonal */
527:   for (i = 0; !sub && i < vs->nr; i++) sub = vs->m[i][col];
528:   if (sub) PetscCall(MatSetUp(sub)); /* Ensure that the sizes are available */
529:   *B = sub;
530:   PetscFunctionReturn(PETSC_SUCCESS);
531: }

533: static PetscErrorCode MatNestFindISRange(Mat A, PetscInt n, const IS list[], IS is, PetscInt *begin, PetscInt *end)
534: {
535:   PetscInt  i, j, size, m;
536:   PetscBool flg;
537:   IS        out, concatenate[2];

539:   PetscFunctionBegin;
540:   PetscAssertPointer(list, 3);
542:   if (begin) {
543:     PetscAssertPointer(begin, 5);
544:     *begin = -1;
545:   }
546:   if (end) {
547:     PetscAssertPointer(end, 6);
548:     *end = -1;
549:   }
550:   for (i = 0; i < n; i++) {
551:     if (!list[i]) continue;
552:     PetscCall(ISEqualUnsorted(list[i], is, &flg));
553:     if (flg) {
554:       if (begin) *begin = i;
555:       if (end) *end = i + 1;
556:       PetscFunctionReturn(PETSC_SUCCESS);
557:     }
558:   }
559:   PetscCall(ISGetSize(is, &size));
560:   for (i = 0; i < n - 1; i++) {
561:     if (!list[i]) continue;
562:     m = 0;
563:     PetscCall(ISConcatenate(PetscObjectComm((PetscObject)A), 2, list + i, &out));
564:     PetscCall(ISGetSize(out, &m));
565:     for (j = i + 2; j < n && m < size; j++) {
566:       if (list[j]) {
567:         concatenate[0] = out;
568:         concatenate[1] = list[j];
569:         PetscCall(ISConcatenate(PetscObjectComm((PetscObject)A), 2, concatenate, &out));
570:         PetscCall(ISDestroy(concatenate));
571:         PetscCall(ISGetSize(out, &m));
572:       }
573:     }
574:     if (m == size) {
575:       PetscCall(ISEqualUnsorted(out, is, &flg));
576:       if (flg) {
577:         if (begin) *begin = i;
578:         if (end) *end = j;
579:         PetscCall(ISDestroy(&out));
580:         PetscFunctionReturn(PETSC_SUCCESS);
581:       }
582:     }
583:     PetscCall(ISDestroy(&out));
584:   }
585:   PetscFunctionReturn(PETSC_SUCCESS);
586: }

588: static PetscErrorCode MatNestFillEmptyMat_Private(Mat A, PetscInt i, PetscInt j, Mat *B)
589: {
590:   Mat_Nest *vs = (Mat_Nest *)A->data;
591:   PetscInt  lr, lc;

593:   PetscFunctionBegin;
594:   PetscCall(MatCreate(PetscObjectComm((PetscObject)A), B));
595:   PetscCall(ISGetLocalSize(vs->isglobal.row[i], &lr));
596:   PetscCall(ISGetLocalSize(vs->isglobal.col[j], &lc));
597:   PetscCall(MatSetSizes(*B, lr, lc, PETSC_DECIDE, PETSC_DECIDE));
598:   PetscCall(MatSetType(*B, MATAIJ));
599:   PetscCall(MatSeqAIJSetPreallocation(*B, 0, NULL));
600:   PetscCall(MatMPIAIJSetPreallocation(*B, 0, NULL, 0, NULL));
601:   PetscCall(MatSetUp(*B));
602:   PetscCall(MatSetOption(*B, MAT_NO_OFF_PROC_ENTRIES, PETSC_TRUE));
603:   PetscCall(MatAssemblyBegin(*B, MAT_FINAL_ASSEMBLY));
604:   PetscCall(MatAssemblyEnd(*B, MAT_FINAL_ASSEMBLY));
605:   PetscFunctionReturn(PETSC_SUCCESS);
606: }

608: static PetscErrorCode MatNestGetBlock_Private(Mat A, PetscInt rbegin, PetscInt rend, PetscInt cbegin, PetscInt cend, Mat *B)
609: {
610:   Mat_Nest  *vs = (Mat_Nest *)A->data;
611:   Mat       *a;
612:   PetscInt   i, j, k, l, nr = rend - rbegin, nc = cend - cbegin;
613:   char       keyname[256];
614:   PetscBool *b;
615:   PetscBool  flg;

617:   PetscFunctionBegin;
618:   *B = NULL;
619:   PetscCall(PetscSNPrintf(keyname, sizeof(keyname), "NestBlock_%" PetscInt_FMT "-%" PetscInt_FMT "x%" PetscInt_FMT "-%" PetscInt_FMT, rbegin, rend, cbegin, cend));
620:   PetscCall(PetscObjectQuery((PetscObject)A, keyname, (PetscObject *)B));
621:   if (*B) PetscFunctionReturn(PETSC_SUCCESS);

623:   PetscCall(PetscMalloc2(nr * nc, &a, nr * nc, &b));
624:   for (i = 0; i < nr; i++) {
625:     for (j = 0; j < nc; j++) {
626:       a[i * nc + j] = vs->m[rbegin + i][cbegin + j];
627:       b[i * nc + j] = PETSC_FALSE;
628:     }
629:   }
630:   if (nc != vs->nc && nr != vs->nr) {
631:     for (i = 0; i < nr; i++) {
632:       for (j = 0; j < nc; j++) {
633:         flg = PETSC_FALSE;
634:         for (k = 0; (k < nr && !flg); k++) {
635:           if (a[j + k * nc]) flg = PETSC_TRUE;
636:         }
637:         if (flg) {
638:           flg = PETSC_FALSE;
639:           for (l = 0; (l < nc && !flg); l++) {
640:             if (a[i * nc + l]) flg = PETSC_TRUE;
641:           }
642:         }
643:         if (!flg) {
644:           b[i * nc + j] = PETSC_TRUE;
645:           PetscCall(MatNestFillEmptyMat_Private(A, rbegin + i, cbegin + j, a + i * nc + j));
646:         }
647:       }
648:     }
649:   }
650:   PetscCall(MatCreateNest(PetscObjectComm((PetscObject)A), nr, nr != vs->nr ? NULL : vs->isglobal.row, nc, nc != vs->nc ? NULL : vs->isglobal.col, a, B));
651:   for (i = 0; i < nr; i++) {
652:     for (j = 0; j < nc; j++) {
653:       if (b[i * nc + j]) PetscCall(MatDestroy(a + i * nc + j));
654:     }
655:   }
656:   PetscCall(PetscFree2(a, b));
657:   (*B)->assembled = A->assembled;
658:   PetscCall(PetscObjectCompose((PetscObject)A, keyname, (PetscObject)*B));
659:   PetscCall(PetscObjectDereference((PetscObject)*B)); /* Leave the only remaining reference in the composition */
660:   PetscFunctionReturn(PETSC_SUCCESS);
661: }

663: static PetscErrorCode MatNestFindSubMat(Mat A, struct MatNestISPair *is, IS isrow, IS iscol, Mat *B)
664: {
665:   Mat_Nest *vs = (Mat_Nest *)A->data;
666:   PetscInt  rbegin, rend, cbegin, cend;

668:   PetscFunctionBegin;
669:   PetscCall(MatNestFindISRange(A, vs->nr, is->row, isrow, &rbegin, &rend));
670:   PetscCall(MatNestFindISRange(A, vs->nc, is->col, iscol, &cbegin, &cend));
671:   if (rend == rbegin + 1 && cend == cbegin + 1) {
672:     if (!vs->m[rbegin][cbegin]) PetscCall(MatNestFillEmptyMat_Private(A, rbegin, cbegin, vs->m[rbegin] + cbegin));
673:     *B = vs->m[rbegin][cbegin];
674:   } else if (rbegin != -1 && cbegin != -1) {
675:     PetscCall(MatNestGetBlock_Private(A, rbegin, rend, cbegin, cend, B));
676:   } else SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_INCOMP, "Could not find index set");
677:   PetscFunctionReturn(PETSC_SUCCESS);
678: }

680: /*
681:    TODO: This does not actually returns a submatrix we can modify
682: */
683: static PetscErrorCode MatCreateSubMatrix_Nest(Mat A, IS isrow, IS iscol, MatReuse reuse, Mat *B)
684: {
685:   Mat_Nest *vs = (Mat_Nest *)A->data;
686:   Mat       sub;

688:   PetscFunctionBegin;
689:   PetscCall(MatNestFindSubMat(A, &vs->isglobal, isrow, iscol, &sub));
690:   switch (reuse) {
691:   case MAT_INITIAL_MATRIX:
692:     PetscCall(PetscObjectReference((PetscObject)sub));
693:     if (sub) PetscCall(PetscObjectStateIncrease((PetscObject)sub));
694:     *B = sub;
695:     break;
696:   case MAT_REUSE_MATRIX:
697:     PetscCheck(sub == *B, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Submatrix was not used before in this call");
698:     if (sub) PetscCall(PetscObjectStateIncrease((PetscObject)sub));
699:     break;
700:   default:
701:     break;
702:   }
703:   PetscFunctionReturn(PETSC_SUCCESS);
704: }

706: static PetscErrorCode MatGetLocalSubMatrix_Nest(Mat A, IS isrow, IS iscol, Mat *B)
707: {
708:   Mat_Nest *vs = (Mat_Nest *)A->data;
709:   Mat       sub;

711:   PetscFunctionBegin;
712:   PetscCall(MatNestFindSubMat(A, &vs->islocal, isrow, iscol, &sub));
713:   /* We allow the submatrix to be NULL, perhaps it would be better for the user to return an empty matrix instead */
714:   PetscCall(PetscObjectReference((PetscObject)sub));
715:   *B = sub;
716:   PetscFunctionReturn(PETSC_SUCCESS);
717: }

719: static PetscErrorCode MatRestoreLocalSubMatrix_Nest(Mat A, IS isrow, IS iscol, Mat *B)
720: {
721:   Mat_Nest *vs = (Mat_Nest *)A->data;
722:   Mat       sub;

724:   PetscFunctionBegin;
725:   PetscCall(MatNestFindSubMat(A, &vs->islocal, isrow, iscol, &sub));
726:   PetscCheck(*B == sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Local submatrix has not been gotten");
727:   if (sub) {
728:     PetscCheck(((PetscObject)sub)->refct > 1, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Local submatrix has had reference count decremented too many times");
729:     PetscCall(MatDestroy(B));
730:   }
731:   PetscFunctionReturn(PETSC_SUCCESS);
732: }

734: static PetscErrorCode MatGetDiagonal_Nest(Mat A, Vec v)
735: {
736:   Mat_Nest *bA = (Mat_Nest *)A->data;
737:   PetscInt  i;

739:   PetscFunctionBegin;
740:   for (i = 0; i < bA->nr; i++) {
741:     Vec bv;
742:     PetscCall(VecGetSubVector(v, bA->isglobal.row[i], &bv));
743:     if (bA->m[i][i]) PetscCall(MatGetDiagonal(bA->m[i][i], bv));
744:     else PetscCall(VecSet(bv, 0.0));
745:     PetscCall(VecRestoreSubVector(v, bA->isglobal.row[i], &bv));
746:   }
747:   PetscFunctionReturn(PETSC_SUCCESS);
748: }

750: static PetscErrorCode MatDiagonalScale_Nest(Mat A, Vec l, Vec r)
751: {
752:   Mat_Nest *bA = (Mat_Nest *)A->data;
753:   Vec       bl, *br;
754:   PetscInt  i, j;

756:   PetscFunctionBegin;
757:   PetscCall(PetscCalloc1(bA->nc, &br));
758:   if (r) {
759:     for (j = 0; j < bA->nc; j++) PetscCall(VecGetSubVector(r, bA->isglobal.col[j], &br[j]));
760:   }
761:   bl = NULL;
762:   for (i = 0; i < bA->nr; i++) {
763:     if (l) PetscCall(VecGetSubVector(l, bA->isglobal.row[i], &bl));
764:     for (j = 0; j < bA->nc; j++) {
765:       if (bA->m[i][j]) PetscCall(MatDiagonalScale(bA->m[i][j], bl, br[j]));
766:     }
767:     if (l) PetscCall(VecRestoreSubVector(l, bA->isglobal.row[i], &bl));
768:   }
769:   if (r) {
770:     for (j = 0; j < bA->nc; j++) PetscCall(VecRestoreSubVector(r, bA->isglobal.col[j], &br[j]));
771:   }
772:   PetscCall(PetscFree(br));
773:   PetscFunctionReturn(PETSC_SUCCESS);
774: }

776: static PetscErrorCode MatScale_Nest(Mat A, PetscScalar a)
777: {
778:   Mat_Nest *bA = (Mat_Nest *)A->data;
779:   PetscInt  i, j;

781:   PetscFunctionBegin;
782:   for (i = 0; i < bA->nr; i++) {
783:     for (j = 0; j < bA->nc; j++) {
784:       if (bA->m[i][j]) PetscCall(MatScale(bA->m[i][j], a));
785:     }
786:   }
787:   PetscFunctionReturn(PETSC_SUCCESS);
788: }

790: static PetscErrorCode MatShift_Nest(Mat A, PetscScalar a)
791: {
792:   Mat_Nest *bA = (Mat_Nest *)A->data;
793:   PetscInt  i;
794:   PetscBool nnzstate = PETSC_FALSE;

796:   PetscFunctionBegin;
797:   for (i = 0; i < bA->nr; i++) {
798:     PetscObjectState subnnzstate = 0;
799:     PetscCheck(bA->m[i][i], PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "No support for shifting an empty diagonal block, insert a matrix in block (%" PetscInt_FMT ",%" PetscInt_FMT ")", i, i);
800:     PetscCall(MatShift(bA->m[i][i], a));
801:     PetscCall(MatGetNonzeroState(bA->m[i][i], &subnnzstate));
802:     nnzstate                     = (PetscBool)(nnzstate || bA->nnzstate[i * bA->nc + i] != subnnzstate);
803:     bA->nnzstate[i * bA->nc + i] = subnnzstate;
804:   }
805:   if (nnzstate) A->nonzerostate++;
806:   PetscFunctionReturn(PETSC_SUCCESS);
807: }

809: static PetscErrorCode MatDiagonalSet_Nest(Mat A, Vec D, InsertMode is)
810: {
811:   Mat_Nest *bA = (Mat_Nest *)A->data;
812:   PetscInt  i;
813:   PetscBool nnzstate = PETSC_FALSE;

815:   PetscFunctionBegin;
816:   for (i = 0; i < bA->nr; i++) {
817:     PetscObjectState subnnzstate = 0;
818:     Vec              bv;
819:     PetscCall(VecGetSubVector(D, bA->isglobal.row[i], &bv));
820:     if (bA->m[i][i]) {
821:       PetscCall(MatDiagonalSet(bA->m[i][i], bv, is));
822:       PetscCall(MatGetNonzeroState(bA->m[i][i], &subnnzstate));
823:     }
824:     PetscCall(VecRestoreSubVector(D, bA->isglobal.row[i], &bv));
825:     nnzstate                     = (PetscBool)(nnzstate || bA->nnzstate[i * bA->nc + i] != subnnzstate);
826:     bA->nnzstate[i * bA->nc + i] = subnnzstate;
827:   }
828:   if (nnzstate) A->nonzerostate++;
829:   PetscFunctionReturn(PETSC_SUCCESS);
830: }

832: static PetscErrorCode MatSetRandom_Nest(Mat A, PetscRandom rctx)
833: {
834:   Mat_Nest *bA = (Mat_Nest *)A->data;
835:   PetscInt  i, j;

837:   PetscFunctionBegin;
838:   for (i = 0; i < bA->nr; i++) {
839:     for (j = 0; j < bA->nc; j++) {
840:       if (bA->m[i][j]) PetscCall(MatSetRandom(bA->m[i][j], rctx));
841:     }
842:   }
843:   PetscFunctionReturn(PETSC_SUCCESS);
844: }

846: static PetscErrorCode MatCreateVecs_Nest(Mat A, Vec *right, Vec *left)
847: {
848:   Mat_Nest *bA = (Mat_Nest *)A->data;
849:   Vec      *L, *R;
850:   MPI_Comm  comm;
851:   PetscInt  i, j;

853:   PetscFunctionBegin;
854:   PetscCall(PetscObjectGetComm((PetscObject)A, &comm));
855:   if (right) {
856:     /* allocate R */
857:     PetscCall(PetscMalloc1(bA->nc, &R));
858:     /* Create the right vectors */
859:     for (j = 0; j < bA->nc; j++) {
860:       for (i = 0; i < bA->nr; i++) {
861:         if (bA->m[i][j]) {
862:           PetscCall(MatCreateVecs(bA->m[i][j], &R[j], NULL));
863:           break;
864:         }
865:       }
866:       PetscCheck(i != bA->nr, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Mat(Nest) contains a null column.");
867:     }
868:     PetscCall(VecCreateNest(comm, bA->nc, bA->isglobal.col, R, right));
869:     /* hand back control to the nest vector */
870:     for (j = 0; j < bA->nc; j++) PetscCall(VecDestroy(&R[j]));
871:     PetscCall(PetscFree(R));
872:   }

874:   if (left) {
875:     /* allocate L */
876:     PetscCall(PetscMalloc1(bA->nr, &L));
877:     /* Create the left vectors */
878:     for (i = 0; i < bA->nr; i++) {
879:       for (j = 0; j < bA->nc; j++) {
880:         if (bA->m[i][j]) {
881:           PetscCall(MatCreateVecs(bA->m[i][j], NULL, &L[i]));
882:           break;
883:         }
884:       }
885:       PetscCheck(j != bA->nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Mat(Nest) contains a null row.");
886:     }

888:     PetscCall(VecCreateNest(comm, bA->nr, bA->isglobal.row, L, left));
889:     for (i = 0; i < bA->nr; i++) PetscCall(VecDestroy(&L[i]));

891:     PetscCall(PetscFree(L));
892:   }
893:   PetscFunctionReturn(PETSC_SUCCESS);
894: }

896: static PetscErrorCode MatView_Nest(Mat A, PetscViewer viewer)
897: {
898:   Mat_Nest *bA = (Mat_Nest *)A->data;
899:   PetscBool isascii, viewSub = PETSC_FALSE;
900:   PetscInt  i, j;

902:   PetscFunctionBegin;
903:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
904:   if (isascii) {
905:     PetscViewerFormat format;

907:     PetscCall(PetscViewerGetFormat(viewer, &format));
908:     if (format == PETSC_VIEWER_ASCII_MATLAB) {
909:       Mat T;

911:       PetscCall(MatConvert(A, MATAIJ, MAT_INITIAL_MATRIX, &T));
912:       PetscCall(MatView(T, viewer));
913:       PetscCall(MatDestroy(&T));
914:       PetscFunctionReturn(PETSC_SUCCESS);
915:     }
916:     PetscCall(PetscOptionsGetBool(((PetscObject)A)->options, ((PetscObject)A)->prefix, "-mat_view_nest_sub", &viewSub, NULL));
917:     PetscCall(PetscViewerASCIIPushTab(viewer));
918:     PetscCall(PetscViewerASCIIPrintf(viewer, "MatNest, rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT ", structure:\n", bA->nr, bA->nc));
919:     for (i = 0; i < bA->nr; i++) {
920:       for (j = 0; j < bA->nc; j++) {
921:         MatType   type;
922:         char      name[256] = "", prefix[256] = "";
923:         PetscInt  NR, NC;
924:         PetscBool isNest = PETSC_FALSE;

926:         if (!bA->m[i][j]) {
927:           PetscCall(PetscViewerASCIIPrintf(viewer, "(%" PetscInt_FMT ",%" PetscInt_FMT ") : NULL\n", i, j));
928:           continue;
929:         }
930:         PetscCall(MatGetSize(bA->m[i][j], &NR, &NC));
931:         PetscCall(MatGetType(bA->m[i][j], &type));
932:         if (((PetscObject)bA->m[i][j])->name) PetscCall(PetscSNPrintf(name, sizeof(name), "name=\"%s\", ", ((PetscObject)bA->m[i][j])->name));
933:         if (((PetscObject)bA->m[i][j])->prefix) PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "prefix=\"%s\", ", ((PetscObject)bA->m[i][j])->prefix));
934:         PetscCall(PetscObjectTypeCompare((PetscObject)bA->m[i][j], MATNEST, &isNest));

936:         PetscCall(PetscViewerASCIIPrintf(viewer, "(%" PetscInt_FMT ",%" PetscInt_FMT ") : %s%stype=%s, rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT "\n", i, j, name, prefix, type, NR, NC));

938:         if (isNest || viewSub) {
939:           PetscCall(PetscViewerASCIIPushTab(viewer)); /* push1 */
940:           PetscCall(MatView(bA->m[i][j], viewer));
941:           PetscCall(PetscViewerASCIIPopTab(viewer)); /* pop1 */
942:         }
943:       }
944:     }
945:     PetscCall(PetscViewerASCIIPopTab(viewer)); /* pop0 */
946:   }
947:   PetscFunctionReturn(PETSC_SUCCESS);
948: }

950: static PetscErrorCode MatZeroEntries_Nest(Mat A)
951: {
952:   Mat_Nest *bA = (Mat_Nest *)A->data;
953:   PetscInt  i, j;

955:   PetscFunctionBegin;
956:   for (i = 0; i < bA->nr; i++) {
957:     for (j = 0; j < bA->nc; j++) {
958:       if (!bA->m[i][j]) continue;
959:       PetscCall(MatZeroEntries(bA->m[i][j]));
960:     }
961:   }
962:   PetscFunctionReturn(PETSC_SUCCESS);
963: }

965: static PetscErrorCode MatCopy_Nest(Mat A, Mat B, MatStructure str)
966: {
967:   Mat_Nest *bA = (Mat_Nest *)A->data, *bB = (Mat_Nest *)B->data;
968:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;
969:   PetscBool nnzstate = PETSC_FALSE;

971:   PetscFunctionBegin;
972:   PetscCheck(nr == bB->nr && nc == bB->nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_INCOMP, "Cannot copy a Mat_Nest of block size (%" PetscInt_FMT ",%" PetscInt_FMT ") to a Mat_Nest of block size (%" PetscInt_FMT ",%" PetscInt_FMT ")", bB->nr, bB->nc, nr, nc);
973:   for (i = 0; i < nr; i++) {
974:     for (j = 0; j < nc; j++) {
975:       PetscObjectState subnnzstate = 0;
976:       if (bA->m[i][j] && bB->m[i][j]) {
977:         PetscCall(MatCopy(bA->m[i][j], bB->m[i][j], str));
978:         PetscCall(MatGetNonzeroState(bB->m[i][j], &subnnzstate));
979:         nnzstate                 = (PetscBool)(nnzstate || bB->nnzstate[i * nc + j] != subnnzstate);
980:         bB->nnzstate[i * nc + j] = subnnzstate;
981:       } else if (bA->m[i][j]) { // bB->m[i][j] is NULL
982:         Mat M;

984:         PetscCheck(str == DIFFERENT_NONZERO_PATTERN || str == UNKNOWN_NONZERO_PATTERN, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_INCOMP, "Matrix block does not exist at %" PetscInt_FMT ",%" PetscInt_FMT ". Use DIFFERENT_NONZERO_PATTERN or UNKNOWN_NONZERO_PATTERN", i, j);
985:         PetscCall(MatDuplicate(bA->m[i][j], MAT_COPY_VALUES, &M));
986:         PetscCall(MatNestSetSubMat(B, i, j, M));
987:         PetscCall(MatDestroy(&M));
988:       } else if (bB->m[i][j]) { // bA->m[i][j] is NULL
989:         PetscCheck(str == DIFFERENT_NONZERO_PATTERN || str == SUBSET_NONZERO_PATTERN || str == UNKNOWN_NONZERO_PATTERN, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_INCOMP, "Matrix block does not exist at %" PetscInt_FMT ",%" PetscInt_FMT ". Use DIFFERENT_NONZERO_PATTERN, SUBSET_NONZERO_PATTERN or UNKNOWN_NONZERO_PATTERN", i, j);
990:         PetscCall(MatNestSetSubMat(B, i, j, NULL));
991:       }
992:     }
993:   }
994:   if (nnzstate) B->nonzerostate++;
995:   PetscFunctionReturn(PETSC_SUCCESS);
996: }

998: static PetscErrorCode MatAXPY_Nest(Mat Y, PetscScalar a, Mat X, MatStructure str)
999: {
1000:   Mat_Nest *bY = (Mat_Nest *)Y->data, *bX = (Mat_Nest *)X->data;
1001:   PetscInt  i, j, nr = bY->nr, nc = bY->nc;
1002:   PetscBool nnzstate = PETSC_FALSE;

1004:   PetscFunctionBegin;
1005:   PetscCheck(nr == bX->nr && nc == bX->nc, PetscObjectComm((PetscObject)Y), PETSC_ERR_ARG_INCOMP, "Cannot AXPY a MatNest of block size (%" PetscInt_FMT ",%" PetscInt_FMT ") with a MatNest of block size (%" PetscInt_FMT ",%" PetscInt_FMT ")", bX->nr, bX->nc, nr, nc);
1006:   for (i = 0; i < nr; i++) {
1007:     for (j = 0; j < nc; j++) {
1008:       PetscObjectState subnnzstate = 0;
1009:       if (bY->m[i][j] && bX->m[i][j]) {
1010:         PetscCall(MatAXPY(bY->m[i][j], a, bX->m[i][j], str));
1011:       } else if (bX->m[i][j]) {
1012:         Mat M;

1014:         PetscCheck(str == DIFFERENT_NONZERO_PATTERN || str == UNKNOWN_NONZERO_PATTERN, PetscObjectComm((PetscObject)Y), PETSC_ERR_ARG_INCOMP, "Matrix block does not exist at %" PetscInt_FMT ",%" PetscInt_FMT ". Use DIFFERENT_NONZERO_PATTERN or UNKNOWN_NONZERO_PATTERN", i, j);
1015:         PetscCall(MatDuplicate(bX->m[i][j], MAT_COPY_VALUES, &M));
1016:         PetscCall(MatScale(M, a));
1017:         PetscCall(MatNestSetSubMat(Y, i, j, M));
1018:         PetscCall(MatDestroy(&M));
1019:       }
1020:       if (bY->m[i][j]) PetscCall(MatGetNonzeroState(bY->m[i][j], &subnnzstate));
1021:       nnzstate                 = (PetscBool)(nnzstate || bY->nnzstate[i * nc + j] != subnnzstate);
1022:       bY->nnzstate[i * nc + j] = subnnzstate;
1023:     }
1024:   }
1025:   if (nnzstate) Y->nonzerostate++;
1026:   PetscFunctionReturn(PETSC_SUCCESS);
1027: }

1029: static PetscErrorCode MatDuplicate_Nest(Mat A, MatDuplicateOption op, Mat *B)
1030: {
1031:   Mat_Nest *bA = (Mat_Nest *)A->data;
1032:   Mat      *b;
1033:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

1035:   PetscFunctionBegin;
1036:   PetscCall(PetscMalloc1(nr * nc, &b));
1037:   for (i = 0; i < nr; i++) {
1038:     for (j = 0; j < nc; j++) {
1039:       if (bA->m[i][j]) PetscCall(MatDuplicate(bA->m[i][j], op, &b[i * nc + j]));
1040:       else b[i * nc + j] = NULL;
1041:     }
1042:   }
1043:   PetscCall(MatCreateNest(PetscObjectComm((PetscObject)A), nr, bA->isglobal.row, nc, bA->isglobal.col, b, B));
1044:   /* Give the new MatNest exclusive ownership */
1045:   for (i = 0; i < nr * nc; i++) PetscCall(MatDestroy(&b[i]));
1046:   PetscCall(PetscFree(b));

1048:   PetscCall(MatAssemblyBegin(*B, MAT_FINAL_ASSEMBLY));
1049:   PetscCall(MatAssemblyEnd(*B, MAT_FINAL_ASSEMBLY));
1050:   PetscFunctionReturn(PETSC_SUCCESS);
1051: }

1053: /* nest api */
1054: static PetscErrorCode MatNestGetSubMat_Nest(Mat A, PetscInt idxm, PetscInt jdxm, Mat *mat)
1055: {
1056:   Mat_Nest *bA = (Mat_Nest *)A->data;

1058:   PetscFunctionBegin;
1059:   PetscCheck(idxm < bA->nr, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Row too large: row %" PetscInt_FMT " max %" PetscInt_FMT, idxm, bA->nr - 1);
1060:   PetscCheck(jdxm < bA->nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Col too large: row %" PetscInt_FMT " max %" PetscInt_FMT, jdxm, bA->nc - 1);
1061:   *mat = bA->m[idxm][jdxm];
1062:   PetscFunctionReturn(PETSC_SUCCESS);
1063: }

1065: /*@
1066:   MatNestGetSubMat - Returns a single, sub-matrix from a `MATNEST`

1068:   Not Collective

1070:   Input Parameters:
1071: + A    - `MATNEST` matrix
1072: . idxm - index of the matrix within the nest matrix
1073: - jdxm - index of the matrix within the nest matrix

1075:   Output Parameter:
1076: . sub - matrix at index `idxm`, `jdxm` within the nest matrix

1078:   Level: developer

1080: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSize()`, `MatNestGetSubMats()`, `MatCreateNest()`, `MatNestSetSubMat()`,
1081:           `MatNestGetLocalISs()`, `MatNestGetISs()`
1082: @*/
1083: PetscErrorCode MatNestGetSubMat(Mat A, PetscInt idxm, PetscInt jdxm, Mat *sub)
1084: {
1085:   PetscFunctionBegin;
1089:   PetscAssertPointer(sub, 4);
1090:   PetscUseMethod(A, "MatNestGetSubMat_C", (Mat, PetscInt, PetscInt, Mat *), (A, idxm, jdxm, sub));
1091:   PetscFunctionReturn(PETSC_SUCCESS);
1092: }

1094: static PetscErrorCode MatNestSetSubMat_Nest(Mat A, PetscInt idxm, PetscInt jdxm, Mat mat)
1095: {
1096:   Mat_Nest *bA = (Mat_Nest *)A->data;
1097:   PetscInt  m, n, M, N, mi, ni, Mi, Ni;

1099:   PetscFunctionBegin;
1100:   PetscCheck(idxm < bA->nr, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Row too large: row %" PetscInt_FMT " max %" PetscInt_FMT, idxm, bA->nr - 1);
1101:   PetscCheck(jdxm < bA->nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Col too large: row %" PetscInt_FMT " max %" PetscInt_FMT, jdxm, bA->nc - 1);
1102:   if (mat) {
1103:     PetscCall(MatGetLocalSize(mat, &m, &n));
1104:     PetscCall(MatGetSize(mat, &M, &N));
1105:     PetscCall(ISGetLocalSize(bA->isglobal.row[idxm], &mi));
1106:     PetscCall(ISGetSize(bA->isglobal.row[idxm], &Mi));
1107:     PetscCall(ISGetLocalSize(bA->isglobal.col[jdxm], &ni));
1108:     PetscCall(ISGetSize(bA->isglobal.col[jdxm], &Ni));
1109:     PetscCheck(M == Mi && N == Ni, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Submatrix dimension (%" PetscInt_FMT ",%" PetscInt_FMT ") incompatible with nest block (%" PetscInt_FMT ",%" PetscInt_FMT ")", M, N, Mi, Ni);
1110:     PetscCheck(m == mi && n == ni, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_INCOMP, "Submatrix local dimension (%" PetscInt_FMT ",%" PetscInt_FMT ") incompatible with nest block (%" PetscInt_FMT ",%" PetscInt_FMT ")", m, n, mi, ni);
1111:   }

1113:   /* do not increase object state */
1114:   if (mat == bA->m[idxm][jdxm]) PetscFunctionReturn(PETSC_SUCCESS);

1116:   PetscCall(PetscObjectReference((PetscObject)mat));
1117:   PetscCall(MatDestroy(&bA->m[idxm][jdxm]));
1118:   bA->m[idxm][jdxm] = mat;
1119:   PetscCall(PetscObjectStateIncrease((PetscObject)A));
1120:   if (mat) PetscCall(MatGetNonzeroState(mat, &bA->nnzstate[idxm * bA->nc + jdxm]));
1121:   else bA->nnzstate[idxm * bA->nc + jdxm] = 0;
1122:   A->nonzerostate++;
1123:   PetscFunctionReturn(PETSC_SUCCESS);
1124: }

1126: /*@
1127:   MatNestSetSubMat - Set a single submatrix in the `MATNEST`

1129:   Logically Collective

1131:   Input Parameters:
1132: + A    - `MATNEST` matrix
1133: . idxm - index of the matrix within the nest matrix
1134: . jdxm - index of the matrix within the nest matrix
1135: - sub  - matrix at index `idxm`, `jdxm` within the nest matrix

1137:   Level: developer

1139:   Notes:
1140:   The new submatrix must have the same size and communicator as that block of the nest.

1142:   This increments the reference count of the submatrix.

1144: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestSetSubMats()`, `MatNestGetSubMats()`, `MatNestGetLocalISs()`, `MatCreateNest()`,
1145:           `MatNestGetSubMat()`, `MatNestGetISs()`, `MatNestGetSize()`
1146: @*/
1147: PetscErrorCode MatNestSetSubMat(Mat A, PetscInt idxm, PetscInt jdxm, Mat sub)
1148: {
1149:   PetscFunctionBegin;
1154:   PetscTryMethod(A, "MatNestSetSubMat_C", (Mat, PetscInt, PetscInt, Mat), (A, idxm, jdxm, sub));
1155:   PetscFunctionReturn(PETSC_SUCCESS);
1156: }

1158: static PetscErrorCode MatNestGetSubMats_Nest(Mat A, PetscInt *M, PetscInt *N, Mat ***mat)
1159: {
1160:   Mat_Nest *bA = (Mat_Nest *)A->data;

1162:   PetscFunctionBegin;
1163:   if (M) *M = bA->nr;
1164:   if (N) *N = bA->nc;
1165:   if (mat) *mat = bA->m;
1166:   PetscFunctionReturn(PETSC_SUCCESS);
1167: }

1169: /*@C
1170:   MatNestGetSubMats - Returns the entire two dimensional array of matrices defining a `MATNEST` matrix.

1172:   Not Collective

1174:   Input Parameter:
1175: . A - nest matrix

1177:   Output Parameters:
1178: + M   - number of submatrix rows in the nest matrix
1179: . N   - number of submatrix columns in the nest matrix
1180: - mat - array of matrices

1182:   Level: developer

1184:   Note:
1185:   The user should not free the array `mat`.

1187:   Fortran Notes:
1188:   This routine has a calling sequence `call MatNestGetSubMats(A, M, N, mat, ierr)`
1189:   where the space allocated for the optional argument `mat` is assumed large enough (if provided).
1190:   Matrices in `mat` are returned in row-major order, see `MatCreateNest()` for an example.

1192: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSize()`, `MatNestGetSubMat()`, `MatNestGetLocalISs()`, `MatCreateNest()`,
1193:           `MatNestSetSubMats()`, `MatNestGetISs()`, `MatNestSetSubMat()`
1194: @*/
1195: PetscErrorCode MatNestGetSubMats(Mat A, PetscInt *M, PetscInt *N, Mat ***mat)
1196: {
1197:   PetscFunctionBegin;
1199:   PetscUseMethod(A, "MatNestGetSubMats_C", (Mat, PetscInt *, PetscInt *, Mat ***), (A, M, N, mat));
1200:   PetscFunctionReturn(PETSC_SUCCESS);
1201: }

1203: static PetscErrorCode MatNestGetSize_Nest(Mat A, PetscInt *M, PetscInt *N)
1204: {
1205:   Mat_Nest *bA = (Mat_Nest *)A->data;

1207:   PetscFunctionBegin;
1208:   if (M) *M = bA->nr;
1209:   if (N) *N = bA->nc;
1210:   PetscFunctionReturn(PETSC_SUCCESS);
1211: }

1213: /*@
1214:   MatNestGetSize - Returns the size of the `MATNEST` matrix.

1216:   Not Collective

1218:   Input Parameter:
1219: . A - `MATNEST` matrix

1221:   Output Parameters:
1222: + M - number of rows in the nested mat
1223: - N - number of cols in the nested mat

1225:   Level: developer

1227:   Note:
1228:   `size` refers to the number of submatrices in the row and column directions of the nested matrix

1230: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSubMat()`, `MatNestGetSubMats()`, `MatCreateNest()`, `MatNestGetLocalISs()`,
1231:           `MatNestGetISs()`
1232: @*/
1233: PetscErrorCode MatNestGetSize(Mat A, PetscInt *M, PetscInt *N)
1234: {
1235:   PetscFunctionBegin;
1237:   PetscUseMethod(A, "MatNestGetSize_C", (Mat, PetscInt *, PetscInt *), (A, M, N));
1238:   PetscFunctionReturn(PETSC_SUCCESS);
1239: }

1241: static PetscErrorCode MatNestGetISs_Nest(Mat A, IS rows[], IS cols[])
1242: {
1243:   Mat_Nest *vs = (Mat_Nest *)A->data;
1244:   PetscInt  i;

1246:   PetscFunctionBegin;
1247:   if (rows)
1248:     for (i = 0; i < vs->nr; i++) rows[i] = vs->isglobal.row[i];
1249:   if (cols)
1250:     for (i = 0; i < vs->nc; i++) cols[i] = vs->isglobal.col[i];
1251:   PetscFunctionReturn(PETSC_SUCCESS);
1252: }

1254: /*@
1255:   MatNestGetISs - Returns the index sets partitioning the row and column spaces of a `MATNEST`

1257:   Not Collective

1259:   Input Parameter:
1260: . A - `MATNEST` matrix

1262:   Output Parameters:
1263: + rows - array of row index sets (pass `NULL` to ignore)
1264: - cols - array of column index sets (pass `NULL` to ignore)

1266:   Level: advanced

1268:   Note:
1269:   The user must have allocated arrays of the correct size. The reference count is not increased on the returned `IS`s.

1271: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSubMat()`, `MatNestGetSubMats()`, `MatNestGetSize()`, `MatNestGetLocalISs()`,
1272:           `MatCreateNest()`, `MatNestSetSubMats()`
1273: @*/
1274: PetscErrorCode MatNestGetISs(Mat A, IS rows[], IS cols[])
1275: {
1276:   PetscFunctionBegin;
1278:   PetscUseMethod(A, "MatNestGetISs_C", (Mat, IS[], IS[]), (A, rows, cols));
1279:   PetscFunctionReturn(PETSC_SUCCESS);
1280: }

1282: static PetscErrorCode MatNestGetLocalISs_Nest(Mat A, IS rows[], IS cols[])
1283: {
1284:   Mat_Nest *vs = (Mat_Nest *)A->data;
1285:   PetscInt  i;

1287:   PetscFunctionBegin;
1288:   if (rows)
1289:     for (i = 0; i < vs->nr; i++) rows[i] = vs->islocal.row[i];
1290:   if (cols)
1291:     for (i = 0; i < vs->nc; i++) cols[i] = vs->islocal.col[i];
1292:   PetscFunctionReturn(PETSC_SUCCESS);
1293: }

1295: /*@
1296:   MatNestGetLocalISs - Returns the index sets partitioning the row and column spaces of a `MATNEST`

1298:   Not Collective

1300:   Input Parameter:
1301: . A - `MATNEST` matrix

1303:   Output Parameters:
1304: + rows - array of row index sets (pass `NULL` to ignore)
1305: - cols - array of column index sets (pass `NULL` to ignore)

1307:   Level: advanced

1309:   Note:
1310:   The user must have allocated arrays of the correct size. The reference count is not increased on the returned `IS`s.

1312: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSubMat()`, `MatNestGetSubMats()`, `MatNestGetSize()`, `MatNestGetISs()`, `MatCreateNest()`,
1313:           `MatNestSetSubMats()`, `MatNestSetSubMat()`
1314: @*/
1315: PetscErrorCode MatNestGetLocalISs(Mat A, IS rows[], IS cols[])
1316: {
1317:   PetscFunctionBegin;
1319:   PetscUseMethod(A, "MatNestGetLocalISs_C", (Mat, IS[], IS[]), (A, rows, cols));
1320:   PetscFunctionReturn(PETSC_SUCCESS);
1321: }

1323: static PetscErrorCode MatNestSetVecType_Nest(Mat A, VecType vtype)
1324: {
1325:   PetscBool flg;

1327:   PetscFunctionBegin;
1328:   PetscCall(PetscStrcmp(vtype, VECNEST, &flg));
1329:   /* In reality, this only distinguishes VECNEST and "other" */
1330:   if (flg) A->ops->getvecs = MatCreateVecs_Nest;
1331:   else A->ops->getvecs = NULL;
1332:   PetscFunctionReturn(PETSC_SUCCESS);
1333: }

1335: /*@
1336:   MatNestSetVecType - Sets the type of `Vec` returned by `MatCreateVecs()`

1338:   Not Collective

1340:   Input Parameters:
1341: + A     - `MATNEST` matrix
1342: - vtype - `VecType` to use for creating vectors

1344:   Level: developer

1346: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreateVecs()`, `MatCreateNest()`, `VecType`
1347: @*/
1348: PetscErrorCode MatNestSetVecType(Mat A, VecType vtype)
1349: {
1350:   PetscFunctionBegin;
1352:   PetscTryMethod(A, "MatNestSetVecType_C", (Mat, VecType), (A, vtype));
1353:   PetscFunctionReturn(PETSC_SUCCESS);
1354: }

1356: static PetscErrorCode MatNestSetSubMats_Nest(Mat A, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[], const Mat a[])
1357: {
1358:   Mat_Nest *s = (Mat_Nest *)A->data;
1359:   PetscInt  i, j, m, n, M, N;
1360:   PetscBool cong, isstd, sametype = PETSC_FALSE;
1361:   VecType   vtype, type;

1363:   PetscFunctionBegin;
1364:   PetscCall(MatReset_Nest(A));

1366:   s->nr = nr;
1367:   s->nc = nc;

1369:   /* Create space for submatrices */
1370:   PetscCall(PetscMalloc1(nr, &s->m));
1371:   PetscCall(PetscMalloc1(nr * nc, &s->m[0]));
1372:   for (i = 0; i < nr; i++) {
1373:     s->m[i] = s->m[0] + i * nc;
1374:     for (j = 0; j < nc; j++) {
1375:       s->m[i][j] = a ? a[i * nc + j] : NULL;
1376:       PetscCall(PetscObjectReference((PetscObject)s->m[i][j]));
1377:     }
1378:   }
1379:   PetscCall(MatGetVecType(A, &vtype));
1380:   PetscCall(PetscStrcmp(vtype, VECSTANDARD, &isstd));
1381:   if (isstd) {
1382:     /* check if all blocks have the same vectype */
1383:     vtype = NULL;
1384:     for (i = 0; i < nr; i++) {
1385:       for (j = 0; j < nc; j++) {
1386:         if (s->m[i][j]) {
1387:           if (!vtype) { /* first visited block */
1388:             PetscCall(MatGetVecType(s->m[i][j], &vtype));
1389:             sametype = PETSC_TRUE;
1390:           } else if (sametype) {
1391:             PetscCall(MatGetVecType(s->m[i][j], &type));
1392:             PetscCall(PetscStrcmp(vtype, type, &sametype));
1393:           }
1394:         }
1395:       }
1396:     }
1397:     if (sametype) { /* propagate vectype */
1398:       PetscCall(MatSetVecType(A, vtype));
1399:     }
1400:   }

1402:   PetscCall(MatSetUp_NestIS_Private(A, nr, is_row, nc, is_col));

1404:   PetscCall(PetscMalloc1(nr, &s->row_len));
1405:   PetscCall(PetscMalloc1(nc, &s->col_len));
1406:   for (i = 0; i < nr; i++) s->row_len[i] = -1;
1407:   for (j = 0; j < nc; j++) s->col_len[j] = -1;

1409:   PetscCall(PetscCalloc1(nr * nc, &s->nnzstate));
1410:   for (i = 0; i < nr; i++) {
1411:     for (j = 0; j < nc; j++) {
1412:       if (s->m[i][j]) PetscCall(MatGetNonzeroState(s->m[i][j], &s->nnzstate[i * nc + j]));
1413:     }
1414:   }

1416:   PetscCall(MatNestGetSizes_Private(A, &m, &n, &M, &N));

1418:   PetscCall(PetscLayoutSetSize(A->rmap, M));
1419:   PetscCall(PetscLayoutSetLocalSize(A->rmap, m));
1420:   PetscCall(PetscLayoutSetSize(A->cmap, N));
1421:   PetscCall(PetscLayoutSetLocalSize(A->cmap, n));

1423:   PetscCall(PetscLayoutSetUp(A->rmap));
1424:   PetscCall(PetscLayoutSetUp(A->cmap));

1426:   /* disable operations that are not supported for non-square matrices,
1427:      or matrices for which is_row != is_col  */
1428:   PetscCall(MatHasCongruentLayouts(A, &cong));
1429:   if (cong && nr != nc) cong = PETSC_FALSE;
1430:   if (cong) {
1431:     for (i = 0; cong && i < nr; i++) PetscCall(ISEqualUnsorted(s->isglobal.row[i], s->isglobal.col[i], &cong));
1432:   }
1433:   if (!cong) {
1434:     A->ops->getdiagonal = NULL;
1435:     A->ops->shift       = NULL;
1436:     A->ops->diagonalset = NULL;
1437:   }

1439:   PetscCall(PetscCalloc2(nr, &s->left, nc, &s->right));
1440:   PetscCall(PetscObjectStateIncrease((PetscObject)A));
1441:   A->nonzerostate++;
1442:   PetscFunctionReturn(PETSC_SUCCESS);
1443: }

1445: /*@
1446:   MatNestSetSubMats - Sets the nested submatrices in a `MATNEST`

1448:   Collective

1450:   Input Parameters:
1451: + A      - `MATNEST` matrix
1452: . nr     - number of nested row blocks
1453: . is_row - index sets for each nested row block, or `NULL` to make contiguous
1454: . nc     - number of nested column blocks
1455: . is_col - index sets for each nested column block, or `NULL` to make contiguous
1456: - a      - array of $ nr \times nc$ submatrices, or `NULL`

1458:   Level: advanced

1460:   Notes:
1461:   This always resets any block matrix information previously set.

1463:   Pass `NULL` in the corresponding entry of `a` for an empty block.

1465:   In both C and Fortran, `a` must be a one-dimensional array representing a two-dimensional row-major order array containing the matrices. See
1466:   `MatCreateNest()` for an example.

1468:   Fortran Note:
1469:   Pass `PETSC_NULL_MAT` in the corresponding entry of `a` for an empty block

1471: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreateNest()`, `MatNestSetSubMat()`, `MatNestGetSubMat()`, `MatNestGetSubMats()`
1472: @*/
1473: PetscErrorCode MatNestSetSubMats(Mat A, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[], const Mat a[]) PeNSS
1474: {
1475:   PetscFunctionBegin;
1478:   PetscCheck(nr >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Number of rows cannot be negative");
1479:   if (nr && is_row) {
1480:     PetscAssertPointer(is_row, 3);
1482:   }
1484:   PetscCheck(nc >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Number of columns cannot be negative");
1485:   if (nc && is_col) {
1486:     PetscAssertPointer(is_col, 5);
1488:   }
1489:   PetscTryMethod(A, "MatNestSetSubMats_C", (Mat, PetscInt, const IS[], PetscInt, const IS[], const Mat[]), (A, nr, is_row, nc, is_col, a));
1490:   PetscFunctionReturn(PETSC_SUCCESS);
1491: }

1493: static PetscErrorCode MatNestCreateAggregateL2G_Private(Mat A, PetscInt n, const IS islocal[], const IS isglobal[], PetscBool colflg, ISLocalToGlobalMapping *ltog)
1494: {
1495:   PetscBool flg;
1496:   PetscInt  i, j, m, mi, *ix;

1498:   PetscFunctionBegin;
1499:   *ltog = NULL;
1500:   for (i = 0, m = 0, flg = PETSC_FALSE; i < n; i++) {
1501:     if (islocal[i]) {
1502:       PetscCall(ISGetLocalSize(islocal[i], &mi));
1503:       flg = PETSC_TRUE; /* We found a non-trivial entry */
1504:     } else {
1505:       PetscCall(ISGetLocalSize(isglobal[i], &mi));
1506:     }
1507:     m += mi;
1508:   }
1509:   if (!flg) PetscFunctionReturn(PETSC_SUCCESS);

1511:   PetscCall(PetscMalloc1(m, &ix));
1512:   for (i = 0, m = 0; i < n; i++) {
1513:     ISLocalToGlobalMapping smap = NULL;
1514:     Mat                    sub  = NULL;
1515:     PetscSF                sf;
1516:     PetscLayout            map;
1517:     const PetscInt        *ix2;

1519:     if (!colflg) {
1520:       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1521:     } else {
1522:       PetscCall(MatNestFindNonzeroSubMatCol(A, i, &sub));
1523:     }
1524:     if (sub) {
1525:       if (!colflg) PetscCall(MatGetLocalToGlobalMapping(sub, &smap, NULL));
1526:       else PetscCall(MatGetLocalToGlobalMapping(sub, NULL, &smap));
1527:     }
1528:     /*
1529:        Now we need to extract the monolithic global indices that correspond to the given split global indices.
1530:        In many/most cases, we only want MatGetLocalSubMatrix() to work, in which case we only need to know the size of the local spaces.
1531:     */
1532:     PetscCall(ISGetIndices(isglobal[i], &ix2));
1533:     if (islocal[i]) {
1534:       PetscInt *ilocal, *iremote;
1535:       PetscInt  mil, nleaves;

1537:       PetscCall(ISGetLocalSize(islocal[i], &mi));
1538:       PetscCheck(smap, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Missing local to global map");
1539:       for (j = 0; j < mi; j++) ix[m + j] = j;
1540:       PetscCall(ISLocalToGlobalMappingApply(smap, mi, ix + m, ix + m));

1542:       /* PetscSFSetGraphLayout does not like negative indices */
1543:       PetscCall(PetscMalloc2(mi, &ilocal, mi, &iremote));
1544:       for (j = 0, nleaves = 0; j < mi; j++) {
1545:         if (ix[m + j] < 0) continue;
1546:         ilocal[nleaves]  = j;
1547:         iremote[nleaves] = ix[m + j];
1548:         nleaves++;
1549:       }
1550:       PetscCall(ISGetLocalSize(isglobal[i], &mil));
1551:       PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)A), &sf));
1552:       PetscCall(PetscLayoutCreate(PetscObjectComm((PetscObject)A), &map));
1553:       PetscCall(PetscLayoutSetLocalSize(map, mil));
1554:       PetscCall(PetscLayoutSetUp(map));
1555:       PetscCall(PetscSFSetGraphLayout(sf, map, nleaves, ilocal, PETSC_USE_POINTER, iremote));
1556:       PetscCall(PetscLayoutDestroy(&map));
1557:       PetscCall(PetscSFBcastBegin(sf, MPIU_INT, ix2, ix + m, MPI_REPLACE));
1558:       PetscCall(PetscSFBcastEnd(sf, MPIU_INT, ix2, ix + m, MPI_REPLACE));
1559:       PetscCall(PetscSFDestroy(&sf));
1560:       PetscCall(PetscFree2(ilocal, iremote));
1561:     } else {
1562:       PetscCall(ISGetLocalSize(isglobal[i], &mi));
1563:       for (j = 0; j < mi; j++) ix[m + j] = ix2[i];
1564:     }
1565:     PetscCall(ISRestoreIndices(isglobal[i], &ix2));
1566:     m += mi;
1567:   }
1568:   PetscCall(ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)A), 1, m, ix, PETSC_OWN_POINTER, ltog));
1569:   PetscFunctionReturn(PETSC_SUCCESS);
1570: }

1572: /* If an IS was provided, there is nothing Nest needs to do, otherwise Nest will build a strided IS */
1573: /*
1574:   nprocessors = NP
1575:   Nest x^T = ((g_0,g_1,...g_nprocs-1), (h_0,h_1,...h_NP-1))
1576:        proc 0: => (g_0,h_0,)
1577:        proc 1: => (g_1,h_1,)
1578:        ...
1579:        proc nprocs-1: => (g_NP-1,h_NP-1,)

1581:             proc 0:                      proc 1:                    proc nprocs-1:
1582:     is[0] = (0,1,2,...,nlocal(g_0)-1)  (0,1,...,nlocal(g_1)-1)  (0,1,...,nlocal(g_NP-1))

1584:             proc 0:
1585:     is[1] = (nlocal(g_0),nlocal(g_0)+1,...,nlocal(g_0)+nlocal(h_0)-1)
1586:             proc 1:
1587:     is[1] = (nlocal(g_1),nlocal(g_1)+1,...,nlocal(g_1)+nlocal(h_1)-1)

1589:             proc NP-1:
1590:     is[1] = (nlocal(g_NP-1),nlocal(g_NP-1)+1,...,nlocal(g_NP-1)+nlocal(h_NP-1)-1)
1591: */
1592: static PetscErrorCode MatSetUp_NestIS_Private(Mat A, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[])
1593: {
1594:   Mat_Nest *vs = (Mat_Nest *)A->data;
1595:   PetscInt  i, j, offset, n, nsum, bs;
1596:   Mat       sub = NULL;

1598:   PetscFunctionBegin;
1599:   PetscCall(PetscMalloc1(nr, &vs->isglobal.row));
1600:   PetscCall(PetscMalloc1(nc, &vs->isglobal.col));
1601:   if (is_row) { /* valid IS is passed in */
1602:     /* refs on is[] are incremented */
1603:     for (i = 0; i < vs->nr; i++) {
1604:       PetscCall(PetscObjectReference((PetscObject)is_row[i]));
1605:       vs->isglobal.row[i] = is_row[i];
1606:     }
1607:   } else { /* Create the ISs by inspecting sizes of a submatrix in each row */
1608:     nsum = 0;
1609:     for (i = 0; i < vs->nr; i++) { /* Add up the local sizes to compute the aggregate offset */
1610:       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1611:       PetscCheck(sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "No nonzero submatrix in row %" PetscInt_FMT, i);
1612:       PetscCall(MatGetLocalSize(sub, &n, NULL));
1613:       PetscCheck(n >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Sizes have not yet been set for submatrix");
1614:       nsum += n;
1615:     }
1616:     PetscCallMPI(MPI_Scan(&nsum, &offset, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)A)));
1617:     offset -= nsum;
1618:     for (i = 0; i < vs->nr; i++) {
1619:       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1620:       PetscCall(MatGetLocalSize(sub, &n, NULL));
1621:       PetscCall(MatGetBlockSizes(sub, &bs, NULL));
1622:       PetscCall(ISCreateStride(PetscObjectComm((PetscObject)sub), n, offset, 1, &vs->isglobal.row[i]));
1623:       PetscCall(ISSetBlockSize(vs->isglobal.row[i], bs));
1624:       offset += n;
1625:     }
1626:   }

1628:   if (is_col) { /* valid IS is passed in */
1629:     /* refs on is[] are incremented */
1630:     for (j = 0; j < vs->nc; j++) {
1631:       PetscCall(PetscObjectReference((PetscObject)is_col[j]));
1632:       vs->isglobal.col[j] = is_col[j];
1633:     }
1634:   } else { /* Create the ISs by inspecting sizes of a submatrix in each column */
1635:     offset = A->cmap->rstart;
1636:     nsum   = 0;
1637:     for (j = 0; j < vs->nc; j++) {
1638:       PetscCall(MatNestFindNonzeroSubMatCol(A, j, &sub));
1639:       PetscCheck(sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "No nonzero submatrix in column %" PetscInt_FMT, i);
1640:       PetscCall(MatGetLocalSize(sub, NULL, &n));
1641:       PetscCheck(n >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Sizes have not yet been set for submatrix");
1642:       nsum += n;
1643:     }
1644:     PetscCallMPI(MPI_Scan(&nsum, &offset, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)A)));
1645:     offset -= nsum;
1646:     for (j = 0; j < vs->nc; j++) {
1647:       PetscCall(MatNestFindNonzeroSubMatCol(A, j, &sub));
1648:       PetscCall(MatGetLocalSize(sub, NULL, &n));
1649:       PetscCall(MatGetBlockSizes(sub, NULL, &bs));
1650:       PetscCall(ISCreateStride(PetscObjectComm((PetscObject)sub), n, offset, 1, &vs->isglobal.col[j]));
1651:       PetscCall(ISSetBlockSize(vs->isglobal.col[j], bs));
1652:       offset += n;
1653:     }
1654:   }

1656:   /* Set up the local ISs */
1657:   PetscCall(PetscMalloc1(vs->nr, &vs->islocal.row));
1658:   PetscCall(PetscMalloc1(vs->nc, &vs->islocal.col));
1659:   for (i = 0, offset = 0; i < vs->nr; i++) {
1660:     IS                     isloc;
1661:     ISLocalToGlobalMapping rmap = NULL;
1662:     PetscInt               nlocal, bs;
1663:     PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1664:     if (sub) PetscCall(MatGetLocalToGlobalMapping(sub, &rmap, NULL));
1665:     if (rmap) {
1666:       PetscCall(MatGetBlockSizes(sub, &bs, NULL));
1667:       PetscCall(ISLocalToGlobalMappingGetSize(rmap, &nlocal));
1668:       PetscCall(ISCreateStride(PETSC_COMM_SELF, nlocal, offset, 1, &isloc));
1669:       PetscCall(ISSetBlockSize(isloc, bs));
1670:     } else {
1671:       nlocal = 0;
1672:       isloc  = NULL;
1673:     }
1674:     vs->islocal.row[i] = isloc;
1675:     offset += nlocal;
1676:   }
1677:   for (i = 0, offset = 0; i < vs->nc; i++) {
1678:     IS                     isloc;
1679:     ISLocalToGlobalMapping cmap = NULL;
1680:     PetscInt               nlocal, bs;
1681:     PetscCall(MatNestFindNonzeroSubMatCol(A, i, &sub));
1682:     if (sub) PetscCall(MatGetLocalToGlobalMapping(sub, NULL, &cmap));
1683:     if (cmap) {
1684:       PetscCall(MatGetBlockSizes(sub, NULL, &bs));
1685:       PetscCall(ISLocalToGlobalMappingGetSize(cmap, &nlocal));
1686:       PetscCall(ISCreateStride(PETSC_COMM_SELF, nlocal, offset, 1, &isloc));
1687:       PetscCall(ISSetBlockSize(isloc, bs));
1688:     } else {
1689:       nlocal = 0;
1690:       isloc  = NULL;
1691:     }
1692:     vs->islocal.col[i] = isloc;
1693:     offset += nlocal;
1694:   }

1696:   /* Set up the aggregate ISLocalToGlobalMapping */
1697:   {
1698:     ISLocalToGlobalMapping rmap, cmap;
1699:     PetscCall(MatNestCreateAggregateL2G_Private(A, vs->nr, vs->islocal.row, vs->isglobal.row, PETSC_FALSE, &rmap));
1700:     PetscCall(MatNestCreateAggregateL2G_Private(A, vs->nc, vs->islocal.col, vs->isglobal.col, PETSC_TRUE, &cmap));
1701:     if (rmap && cmap) PetscCall(MatSetLocalToGlobalMapping(A, rmap, cmap));
1702:     PetscCall(ISLocalToGlobalMappingDestroy(&rmap));
1703:     PetscCall(ISLocalToGlobalMappingDestroy(&cmap));
1704:   }

1706:   if (PetscDefined(USE_DEBUG)) {
1707:     for (i = 0; i < vs->nr; i++) {
1708:       for (j = 0; j < vs->nc; j++) {
1709:         PetscInt m, n, M, N, mi, ni, Mi, Ni;
1710:         Mat      B = vs->m[i][j];
1711:         if (!B) continue;
1712:         PetscCall(MatGetSize(B, &M, &N));
1713:         PetscCall(MatGetLocalSize(B, &m, &n));
1714:         PetscCall(ISGetSize(vs->isglobal.row[i], &Mi));
1715:         PetscCall(ISGetSize(vs->isglobal.col[j], &Ni));
1716:         PetscCall(ISGetLocalSize(vs->isglobal.row[i], &mi));
1717:         PetscCall(ISGetLocalSize(vs->isglobal.col[j], &ni));
1718:         PetscCheck(M == Mi && N == Ni, PetscObjectComm((PetscObject)sub), PETSC_ERR_ARG_INCOMP, "Global sizes (%" PetscInt_FMT ",%" PetscInt_FMT ") of nested submatrix (%" PetscInt_FMT ",%" PetscInt_FMT ") do not agree with space defined by index sets (%" PetscInt_FMT ",%" PetscInt_FMT ")", M, N, i, j, Mi, Ni);
1719:         PetscCheck(m == mi && n == ni, PetscObjectComm((PetscObject)sub), PETSC_ERR_ARG_INCOMP, "Local sizes (%" PetscInt_FMT ",%" PetscInt_FMT ") of nested submatrix (%" PetscInt_FMT ",%" PetscInt_FMT ") do not agree with space defined by index sets (%" PetscInt_FMT ",%" PetscInt_FMT ")", m, n, i, j, mi, ni);
1720:       }
1721:     }
1722:   }

1724:   /* Set A->assembled if all non-null blocks are currently assembled */
1725:   for (i = 0; i < vs->nr; i++) {
1726:     for (j = 0; j < vs->nc; j++) {
1727:       if (vs->m[i][j] && !vs->m[i][j]->assembled) PetscFunctionReturn(PETSC_SUCCESS);
1728:     }
1729:   }
1730:   A->assembled = PETSC_TRUE;
1731:   PetscFunctionReturn(PETSC_SUCCESS);
1732: }

1734: /*@C
1735:   MatCreateNest - Creates a new `MATNEST` matrix containing several nested submatrices, each stored separately

1737:   Collective

1739:   Input Parameters:
1740: + comm   - Communicator for the new `MATNEST`
1741: . nr     - number of nested row blocks
1742: . is_row - index sets for each nested row block, or `NULL` to make contiguous
1743: . nc     - number of nested column blocks
1744: . is_col - index sets for each nested column block, or `NULL` to make contiguous
1745: - a      - array of $nr \times nc$ submatrices, empty submatrices can be passed using `NULL`

1747:   Output Parameter:
1748: . B - new matrix

1750:   Level: advanced

1752:   Note:
1753:   In both C and Fortran, `a` must be a one-dimensional array representing a two-dimensional row-major order array holding references to the matrices.
1754:   For instance, to represent the matrix
1755:   $\begin{bmatrix} A_{11} & A_{12} \\ A_{21} & A_{22}\end{bmatrix}$
1756:   one should use `Mat a[4]={A11,A12,A21,A22}`.

1758:   Fortran Note:
1759:   Pass `PETSC_NULL_MAT` in the corresponding entry of `a` for an empty block

1761: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreate()`, `VecCreateNest()`, `DMCreateMatrix()`, `MatNestSetSubMat()`,
1762:           `MatNestGetSubMat()`, `MatNestGetLocalISs()`, `MatNestGetSize()`,
1763:           `MatNestGetISs()`, `MatNestSetSubMats()`, `MatNestGetSubMats()`
1764: @*/
1765: PetscErrorCode MatCreateNest(MPI_Comm comm, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[], const Mat a[], Mat *B) PeNSS
1766: {
1767:   PetscFunctionBegin;
1768:   PetscCall(MatCreate(comm, B));
1769:   PetscCall(MatSetType(*B, MATNEST));
1770:   (*B)->preallocated = PETSC_TRUE;
1771:   PetscCall(MatNestSetSubMats(*B, nr, is_row, nc, is_col, a));
1772:   PetscFunctionReturn(PETSC_SUCCESS);
1773: }

1775: static PetscErrorCode MatConvert_Nest_SeqAIJ_fast(Mat A, MatType newtype, MatReuse reuse, Mat *newmat)
1776: {
1777:   Mat_Nest     *nest = (Mat_Nest *)A->data;
1778:   Mat          *trans;
1779:   PetscScalar **avv;
1780:   PetscScalar  *vv;
1781:   PetscInt    **aii, **ajj;
1782:   PetscInt     *ii, *jj, *ci;
1783:   PetscInt      nr, nc, nnz, i, j;
1784:   PetscBool     done;

1786:   PetscFunctionBegin;
1787:   PetscCall(MatGetSize(A, &nr, &nc));
1788:   if (reuse == MAT_REUSE_MATRIX) {
1789:     PetscInt rnr;

1791:     PetscCall(MatGetRowIJ(*newmat, 0, PETSC_FALSE, PETSC_FALSE, &rnr, (const PetscInt **)&ii, (const PetscInt **)&jj, &done));
1792:     PetscCheck(done, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "MatGetRowIJ");
1793:     PetscCheck(rnr == nr, PetscObjectComm((PetscObject)A), PETSC_ERR_USER, "Cannot reuse matrix, wrong number of rows");
1794:     PetscCall(MatSeqAIJGetArray(*newmat, &vv));
1795:   }
1796:   /* extract CSR for nested SeqAIJ matrices */
1797:   nnz = 0;
1798:   PetscCall(PetscCalloc4(nest->nr * nest->nc, &aii, nest->nr * nest->nc, &ajj, nest->nr * nest->nc, &avv, nest->nr * nest->nc, &trans));
1799:   for (i = 0; i < nest->nr; ++i) {
1800:     for (j = 0; j < nest->nc; ++j) {
1801:       Mat B = nest->m[i][j];
1802:       if (B) {
1803:         PetscScalar *naa;
1804:         PetscInt    *nii, *njj, nnr;
1805:         PetscBool    istrans;

1807:         PetscCall(PetscObjectTypeCompare((PetscObject)B, MATTRANSPOSEVIRTUAL, &istrans));
1808:         if (istrans) {
1809:           Mat Bt;

1811:           PetscCall(MatTransposeGetMat(B, &Bt));
1812:           PetscCall(MatTranspose(Bt, MAT_INITIAL_MATRIX, &trans[i * nest->nc + j]));
1813:           B = trans[i * nest->nc + j];
1814:         } else {
1815:           PetscCall(PetscObjectTypeCompare((PetscObject)B, MATHERMITIANTRANSPOSEVIRTUAL, &istrans));
1816:           if (istrans) {
1817:             Mat Bt;

1819:             PetscCall(MatHermitianTransposeGetMat(B, &Bt));
1820:             PetscCall(MatHermitianTranspose(Bt, MAT_INITIAL_MATRIX, &trans[i * nest->nc + j]));
1821:             B = trans[i * nest->nc + j];
1822:           }
1823:         }
1824:         PetscCall(MatGetRowIJ(B, 0, PETSC_FALSE, PETSC_FALSE, &nnr, (const PetscInt **)&nii, (const PetscInt **)&njj, &done));
1825:         PetscCheck(done, PetscObjectComm((PetscObject)B), PETSC_ERR_PLIB, "MatGetRowIJ");
1826:         PetscCall(MatSeqAIJGetArray(B, &naa));
1827:         nnz += nii[nnr];

1829:         aii[i * nest->nc + j] = nii;
1830:         ajj[i * nest->nc + j] = njj;
1831:         avv[i * nest->nc + j] = naa;
1832:       }
1833:     }
1834:   }
1835:   if (reuse != MAT_REUSE_MATRIX) {
1836:     PetscCall(PetscMalloc1(nr + 1, &ii));
1837:     PetscCall(PetscMalloc1(nnz, &jj));
1838:     PetscCall(PetscMalloc1(nnz, &vv));
1839:   } else {
1840:     PetscCheck(nnz == ii[nr], PetscObjectComm((PetscObject)A), PETSC_ERR_USER, "Cannot reuse matrix, wrong number of nonzeros");
1841:   }

1843:   /* new row pointer */
1844:   PetscCall(PetscArrayzero(ii, nr + 1));
1845:   for (i = 0; i < nest->nr; ++i) {
1846:     PetscInt ncr, rst;

1848:     PetscCall(ISStrideGetInfo(nest->isglobal.row[i], &rst, NULL));
1849:     PetscCall(ISGetLocalSize(nest->isglobal.row[i], &ncr));
1850:     for (j = 0; j < nest->nc; ++j) {
1851:       if (aii[i * nest->nc + j]) {
1852:         PetscInt *nii = aii[i * nest->nc + j];
1853:         PetscInt  ir;

1855:         for (ir = rst; ir < ncr + rst; ++ir) {
1856:           ii[ir + 1] += nii[1] - nii[0];
1857:           nii++;
1858:         }
1859:       }
1860:     }
1861:   }
1862:   for (i = 0; i < nr; i++) ii[i + 1] += ii[i];

1864:   /* construct CSR for the new matrix */
1865:   PetscCall(PetscCalloc1(nr, &ci));
1866:   for (i = 0; i < nest->nr; ++i) {
1867:     PetscInt ncr, rst;

1869:     PetscCall(ISStrideGetInfo(nest->isglobal.row[i], &rst, NULL));
1870:     PetscCall(ISGetLocalSize(nest->isglobal.row[i], &ncr));
1871:     for (j = 0; j < nest->nc; ++j) {
1872:       if (aii[i * nest->nc + j]) {
1873:         PetscScalar *nvv = avv[i * nest->nc + j], vscale = 1.0, vshift = 0.0;
1874:         PetscInt    *nii = aii[i * nest->nc + j];
1875:         PetscInt    *njj = ajj[i * nest->nc + j];
1876:         PetscInt     ir, cst;

1878:         if (trans[i * nest->nc + j]) {
1879:           vscale = ((Mat_Shell *)nest->m[i][j]->data)->vscale;
1880:           vshift = ((Mat_Shell *)nest->m[i][j]->data)->vshift;
1881:         }
1882:         PetscCall(ISStrideGetInfo(nest->isglobal.col[j], &cst, NULL));
1883:         for (ir = rst; ir < ncr + rst; ++ir) {
1884:           PetscInt ij, rsize = nii[1] - nii[0], ist = ii[ir] + ci[ir];

1886:           for (ij = 0; ij < rsize; ij++) {
1887:             jj[ist + ij] = *njj + cst;
1888:             vv[ist + ij] = vscale * *nvv;
1889:             if (PetscUnlikely(vshift != 0.0 && *njj == ir - rst)) vv[ist + ij] += vshift;
1890:             njj++;
1891:             nvv++;
1892:           }
1893:           ci[ir] += rsize;
1894:           nii++;
1895:         }
1896:       }
1897:     }
1898:   }
1899:   PetscCall(PetscFree(ci));

1901:   /* restore info */
1902:   for (i = 0; i < nest->nr; ++i) {
1903:     for (j = 0; j < nest->nc; ++j) {
1904:       Mat B = nest->m[i][j];
1905:       if (B) {
1906:         PetscInt nnr = 0, k = i * nest->nc + j;

1908:         B = (trans[k] ? trans[k] : B);
1909:         PetscCall(MatRestoreRowIJ(B, 0, PETSC_FALSE, PETSC_FALSE, &nnr, (const PetscInt **)&aii[k], (const PetscInt **)&ajj[k], &done));
1910:         PetscCheck(done, PetscObjectComm((PetscObject)B), PETSC_ERR_PLIB, "MatRestoreRowIJ");
1911:         PetscCall(MatSeqAIJRestoreArray(B, &avv[k]));
1912:         PetscCall(MatDestroy(&trans[k]));
1913:       }
1914:     }
1915:   }
1916:   PetscCall(PetscFree4(aii, ajj, avv, trans));

1918:   /* finalize newmat */
1919:   if (reuse == MAT_INITIAL_MATRIX) {
1920:     PetscCall(MatCreateSeqAIJWithArrays(PetscObjectComm((PetscObject)A), nr, nc, ii, jj, vv, newmat));
1921:   } else if (reuse == MAT_INPLACE_MATRIX) {
1922:     Mat B;

1924:     PetscCall(MatCreateSeqAIJWithArrays(PetscObjectComm((PetscObject)A), nr, nc, ii, jj, vv, &B));
1925:     PetscCall(MatHeaderReplace(A, &B));
1926:   }
1927:   PetscCall(MatAssemblyBegin(*newmat, MAT_FINAL_ASSEMBLY));
1928:   PetscCall(MatAssemblyEnd(*newmat, MAT_FINAL_ASSEMBLY));
1929:   {
1930:     Mat_SeqAIJ *a = (Mat_SeqAIJ *)((*newmat)->data);
1931:     a->free_a     = PETSC_TRUE;
1932:     a->free_ij    = PETSC_TRUE;
1933:   }
1934:   PetscFunctionReturn(PETSC_SUCCESS);
1935: }

1937: PETSC_INTERN PetscErrorCode MatAXPY_Dense_Nest(Mat Y, PetscScalar a, Mat X)
1938: {
1939:   Mat_Nest *nest = (Mat_Nest *)X->data;
1940:   PetscInt  i, j, k, rstart;
1941:   PetscBool flg;

1943:   PetscFunctionBegin;
1944:   /* Fill by row */
1945:   for (j = 0; j < nest->nc; ++j) {
1946:     /* Using global column indices and ISAllGather() is not scalable. */
1947:     IS              bNis;
1948:     PetscInt        bN;
1949:     const PetscInt *bNindices;
1950:     PetscCall(ISAllGather(nest->isglobal.col[j], &bNis));
1951:     PetscCall(ISGetSize(bNis, &bN));
1952:     PetscCall(ISGetIndices(bNis, &bNindices));
1953:     for (i = 0; i < nest->nr; ++i) {
1954:       Mat             B = nest->m[i][j], D = NULL;
1955:       PetscInt        bm, br;
1956:       const PetscInt *bmindices;
1957:       if (!B) continue;
1958:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATTRANSPOSEVIRTUAL, MATHERMITIANTRANSPOSEVIRTUAL, ""));
1959:       if (flg) {
1960:         PetscTryMethod(B, "MatTransposeGetMat_C", (Mat, Mat *), (B, &D));
1961:         PetscTryMethod(B, "MatHermitianTransposeGetMat_C", (Mat, Mat *), (B, &D));
1962:         PetscCall(MatConvert(B, ((PetscObject)D)->type_name, MAT_INITIAL_MATRIX, &D));
1963:         B = D;
1964:       }
1965:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATSEQSBAIJ, MATMPISBAIJ, ""));
1966:       if (flg) {
1967:         if (D) PetscCall(MatConvert(D, MATBAIJ, MAT_INPLACE_MATRIX, &D));
1968:         else PetscCall(MatConvert(B, MATBAIJ, MAT_INITIAL_MATRIX, &D));
1969:         B = D;
1970:       }
1971:       PetscCall(ISGetLocalSize(nest->isglobal.row[i], &bm));
1972:       PetscCall(ISGetIndices(nest->isglobal.row[i], &bmindices));
1973:       PetscCall(MatGetOwnershipRange(B, &rstart, NULL));
1974:       for (br = 0; br < bm; ++br) {
1975:         PetscInt           row = bmindices[br], brncols, *cols;
1976:         const PetscInt    *brcols;
1977:         const PetscScalar *brcoldata;
1978:         PetscScalar       *vals = NULL;
1979:         PetscCall(MatGetRow(B, br + rstart, &brncols, &brcols, &brcoldata));
1980:         PetscCall(PetscMalloc1(brncols, &cols));
1981:         for (k = 0; k < brncols; k++) cols[k] = bNindices[brcols[k]];
1982:         /*
1983:           Nest blocks are required to be nonoverlapping -- otherwise nest and monolithic index layouts wouldn't match.
1984:           Thus, we could use INSERT_VALUES, but I prefer ADD_VALUES.
1985:          */
1986:         if (a != 1.0) {
1987:           PetscCall(PetscMalloc1(brncols, &vals));
1988:           for (k = 0; k < brncols; k++) vals[k] = a * brcoldata[k];
1989:           PetscCall(MatSetValues(Y, 1, &row, brncols, cols, vals, ADD_VALUES));
1990:           PetscCall(PetscFree(vals));
1991:         } else {
1992:           PetscCall(MatSetValues(Y, 1, &row, brncols, cols, brcoldata, ADD_VALUES));
1993:         }
1994:         PetscCall(MatRestoreRow(B, br + rstart, &brncols, &brcols, &brcoldata));
1995:         PetscCall(PetscFree(cols));
1996:       }
1997:       PetscCall(MatDestroy(&D));
1998:       PetscCall(ISRestoreIndices(nest->isglobal.row[i], &bmindices));
1999:     }
2000:     PetscCall(ISRestoreIndices(bNis, &bNindices));
2001:     PetscCall(ISDestroy(&bNis));
2002:   }
2003:   PetscCall(MatAssemblyBegin(Y, MAT_FINAL_ASSEMBLY));
2004:   PetscCall(MatAssemblyEnd(Y, MAT_FINAL_ASSEMBLY));
2005:   PetscFunctionReturn(PETSC_SUCCESS);
2006: }

2008: static PetscErrorCode MatConvert_Nest_AIJ(Mat A, MatType newtype, MatReuse reuse, Mat *newmat)
2009: {
2010:   Mat_Nest   *nest = (Mat_Nest *)A->data;
2011:   PetscInt    m, n, M, N, i, j, k, *dnnz, *onnz = NULL, rstart, cstart, cend;
2012:   PetscMPIInt size;
2013:   Mat         C;

2015:   PetscFunctionBegin;
2016:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
2017:   if (size == 1) { /* look for a special case with SeqAIJ matrices and strided-1, contiguous, blocks */
2018:     PetscInt  nf;
2019:     PetscBool fast;

2021:     PetscCall(PetscStrcmp(newtype, MATAIJ, &fast));
2022:     if (!fast) PetscCall(PetscStrcmp(newtype, MATSEQAIJ, &fast));
2023:     for (i = 0; i < nest->nr && fast; ++i) {
2024:       for (j = 0; j < nest->nc && fast; ++j) {
2025:         Mat B = nest->m[i][j];
2026:         if (B) {
2027:           PetscCall(PetscObjectTypeCompare((PetscObject)B, MATSEQAIJ, &fast));
2028:           if (!fast) {
2029:             PetscBool istrans;

2031:             PetscCall(PetscObjectTypeCompare((PetscObject)B, MATTRANSPOSEVIRTUAL, &istrans));
2032:             if (istrans) {
2033:               Mat Bt;

2035:               PetscCall(MatTransposeGetMat(B, &Bt));
2036:               PetscCall(PetscObjectTypeCompare((PetscObject)Bt, MATSEQAIJ, &fast));
2037:             } else {
2038:               PetscCall(PetscObjectTypeCompare((PetscObject)B, MATHERMITIANTRANSPOSEVIRTUAL, &istrans));
2039:               if (istrans) {
2040:                 Mat Bt;

2042:                 PetscCall(MatHermitianTransposeGetMat(B, &Bt));
2043:                 PetscCall(PetscObjectTypeCompare((PetscObject)Bt, MATSEQAIJ, &fast));
2044:               }
2045:             }
2046:             if (fast) fast = (PetscBool)(!((Mat_Shell *)B->data)->zrows && !((Mat_Shell *)B->data)->zcols && !((Mat_Shell *)B->data)->axpy && !((Mat_Shell *)B->data)->left && !((Mat_Shell *)B->data)->right && !((Mat_Shell *)B->data)->dshift);
2047:           }
2048:         }
2049:       }
2050:     }
2051:     for (i = 0, nf = 0; i < nest->nr && fast; ++i) {
2052:       PetscCall(PetscObjectTypeCompare((PetscObject)nest->isglobal.row[i], ISSTRIDE, &fast));
2053:       if (fast) {
2054:         PetscInt f, s;

2056:         PetscCall(ISStrideGetInfo(nest->isglobal.row[i], &f, &s));
2057:         if (f != nf || s != 1) {
2058:           fast = PETSC_FALSE;
2059:         } else {
2060:           PetscCall(ISGetSize(nest->isglobal.row[i], &f));
2061:           nf += f;
2062:         }
2063:       }
2064:     }
2065:     for (i = 0, nf = 0; i < nest->nc && fast; ++i) {
2066:       PetscCall(PetscObjectTypeCompare((PetscObject)nest->isglobal.col[i], ISSTRIDE, &fast));
2067:       if (fast) {
2068:         PetscInt f, s;

2070:         PetscCall(ISStrideGetInfo(nest->isglobal.col[i], &f, &s));
2071:         if (f != nf || s != 1) {
2072:           fast = PETSC_FALSE;
2073:         } else {
2074:           PetscCall(ISGetSize(nest->isglobal.col[i], &f));
2075:           nf += f;
2076:         }
2077:       }
2078:     }
2079:     if (fast) {
2080:       PetscCall(MatConvert_Nest_SeqAIJ_fast(A, newtype, reuse, newmat));
2081:       PetscFunctionReturn(PETSC_SUCCESS);
2082:     }
2083:   }
2084:   PetscCall(MatGetSize(A, &M, &N));
2085:   PetscCall(MatGetLocalSize(A, &m, &n));
2086:   PetscCall(MatGetOwnershipRangeColumn(A, &cstart, &cend));
2087:   if (reuse == MAT_REUSE_MATRIX) C = *newmat;
2088:   else {
2089:     PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2090:     PetscCall(MatSetType(C, newtype));
2091:     PetscCall(MatSetSizes(C, m, n, M, N));
2092:   }
2093:   PetscCall(PetscMalloc1(2 * m, &dnnz));
2094:   if (m) {
2095:     onnz = dnnz + m;
2096:     for (k = 0; k < m; k++) {
2097:       dnnz[k] = 0;
2098:       onnz[k] = 0;
2099:     }
2100:   }
2101:   for (j = 0; j < nest->nc; ++j) {
2102:     IS              bNis;
2103:     PetscInt        bN;
2104:     const PetscInt *bNindices;
2105:     PetscBool       flg;
2106:     /* Using global column indices and ISAllGather() is not scalable. */
2107:     PetscCall(ISAllGather(nest->isglobal.col[j], &bNis));
2108:     PetscCall(ISGetSize(bNis, &bN));
2109:     PetscCall(ISGetIndices(bNis, &bNindices));
2110:     for (i = 0; i < nest->nr; ++i) {
2111:       PetscSF         bmsf;
2112:       PetscSFNode    *iremote;
2113:       Mat             B = nest->m[i][j], D = NULL;
2114:       PetscInt        bm, *sub_dnnz, *sub_onnz, br;
2115:       const PetscInt *bmindices;
2116:       if (!B) continue;
2117:       PetscCall(ISGetLocalSize(nest->isglobal.row[i], &bm));
2118:       PetscCall(ISGetIndices(nest->isglobal.row[i], &bmindices));
2119:       PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)A), &bmsf));
2120:       PetscCall(PetscMalloc1(bm, &iremote));
2121:       PetscCall(PetscMalloc1(bm, &sub_dnnz));
2122:       PetscCall(PetscMalloc1(bm, &sub_onnz));
2123:       for (k = 0; k < bm; ++k) {
2124:         sub_dnnz[k] = 0;
2125:         sub_onnz[k] = 0;
2126:       }
2127:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATTRANSPOSEVIRTUAL, MATHERMITIANTRANSPOSEVIRTUAL, ""));
2128:       if (flg) {
2129:         PetscTryMethod(B, "MatTransposeGetMat_C", (Mat, Mat *), (B, &D));
2130:         PetscTryMethod(B, "MatHermitianTransposeGetMat_C", (Mat, Mat *), (B, &D));
2131:         PetscCall(MatConvert(B, ((PetscObject)D)->type_name, MAT_INITIAL_MATRIX, &D));
2132:         B = D;
2133:       }
2134:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATSEQSBAIJ, MATMPISBAIJ, ""));
2135:       if (flg) {
2136:         if (D) PetscCall(MatConvert(D, MATBAIJ, MAT_INPLACE_MATRIX, &D));
2137:         else PetscCall(MatConvert(B, MATBAIJ, MAT_INITIAL_MATRIX, &D));
2138:         B = D;
2139:       }
2140:       /*
2141:        Locate the owners for all of the locally-owned global row indices for this row block.
2142:        These determine the roots of PetscSF used to communicate preallocation data to row owners.
2143:        The roots correspond to the dnnz and onnz entries; thus, there are two roots per row.
2144:        */
2145:       PetscCall(MatGetOwnershipRange(B, &rstart, NULL));
2146:       for (br = 0; br < bm; ++br) {
2147:         PetscInt        row = bmindices[br], brncols, col;
2148:         const PetscInt *brcols;
2149:         PetscInt        rowrel   = 0; /* row's relative index on its owner rank */
2150:         PetscMPIInt     rowowner = 0;
2151:         PetscCall(PetscLayoutFindOwnerIndex(A->rmap, row, &rowowner, &rowrel));
2152:         /* how many roots  */
2153:         iremote[br].rank  = rowowner;
2154:         iremote[br].index = rowrel; /* edge from bmdnnz to dnnz */
2155:         /* get nonzero pattern */
2156:         PetscCall(MatGetRow(B, br + rstart, &brncols, &brcols, NULL));
2157:         for (k = 0; k < brncols; k++) {
2158:           col = bNindices[brcols[k]];
2159:           if (col >= A->cmap->range[rowowner] && col < A->cmap->range[rowowner + 1]) {
2160:             sub_dnnz[br]++;
2161:           } else {
2162:             sub_onnz[br]++;
2163:           }
2164:         }
2165:         PetscCall(MatRestoreRow(B, br + rstart, &brncols, &brcols, NULL));
2166:       }
2167:       PetscCall(MatDestroy(&D));
2168:       PetscCall(ISRestoreIndices(nest->isglobal.row[i], &bmindices));
2169:       /* bsf will have to take care of disposing of bedges. */
2170:       PetscCall(PetscSFSetGraph(bmsf, m, bm, NULL, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));
2171:       PetscCall(PetscSFReduceBegin(bmsf, MPIU_INT, sub_dnnz, dnnz, MPI_SUM));
2172:       PetscCall(PetscSFReduceEnd(bmsf, MPIU_INT, sub_dnnz, dnnz, MPI_SUM));
2173:       PetscCall(PetscSFReduceBegin(bmsf, MPIU_INT, sub_onnz, onnz, MPI_SUM));
2174:       PetscCall(PetscSFReduceEnd(bmsf, MPIU_INT, sub_onnz, onnz, MPI_SUM));
2175:       PetscCall(PetscFree(sub_dnnz));
2176:       PetscCall(PetscFree(sub_onnz));
2177:       PetscCall(PetscSFDestroy(&bmsf));
2178:     }
2179:     PetscCall(ISRestoreIndices(bNis, &bNindices));
2180:     PetscCall(ISDestroy(&bNis));
2181:   }
2182:   /* Resize preallocation if overestimated */
2183:   for (i = 0; i < m; i++) {
2184:     dnnz[i] = PetscMin(dnnz[i], A->cmap->n);
2185:     onnz[i] = PetscMin(onnz[i], A->cmap->N - A->cmap->n);
2186:   }
2187:   PetscCall(MatSeqAIJSetPreallocation(C, 0, dnnz));
2188:   PetscCall(MatMPIAIJSetPreallocation(C, 0, dnnz, 0, onnz));
2189:   PetscCall(PetscFree(dnnz));
2190:   PetscCall(MatAXPY_Dense_Nest(C, 1.0, A));
2191:   if (reuse == MAT_INPLACE_MATRIX) PetscCall(MatHeaderReplace(A, &C));
2192:   else *newmat = C;
2193:   PetscFunctionReturn(PETSC_SUCCESS);
2194: }

2196: static PetscErrorCode MatConvert_Nest_Dense(Mat A, MatType newtype, MatReuse reuse, Mat *newmat)
2197: {
2198:   Mat      B;
2199:   PetscInt m, n, M, N;

2201:   PetscFunctionBegin;
2202:   PetscCall(MatGetSize(A, &M, &N));
2203:   PetscCall(MatGetLocalSize(A, &m, &n));
2204:   if (reuse == MAT_REUSE_MATRIX) {
2205:     B = *newmat;
2206:     PetscCall(MatZeroEntries(B));
2207:   } else {
2208:     PetscCall(MatCreateDense(PetscObjectComm((PetscObject)A), m, PETSC_DECIDE, M, N, NULL, &B));
2209:   }
2210:   PetscCall(MatAXPY_Dense_Nest(B, 1.0, A));
2211:   if (reuse == MAT_INPLACE_MATRIX) PetscCall(MatHeaderReplace(A, &B));
2212:   else if (reuse == MAT_INITIAL_MATRIX) *newmat = B;
2213:   PetscFunctionReturn(PETSC_SUCCESS);
2214: }

2216: static PetscErrorCode MatHasOperation_Nest(Mat mat, MatOperation op, PetscBool *has)
2217: {
2218:   Mat_Nest    *bA = (Mat_Nest *)mat->data;
2219:   MatOperation opAdd;
2220:   PetscInt     i, j, nr = bA->nr, nc = bA->nc;
2221:   PetscBool    flg;

2223:   PetscFunctionBegin;
2224:   *has = PETSC_FALSE;
2225:   if (op == MATOP_MULT || op == MATOP_MULT_ADD || op == MATOP_MULT_TRANSPOSE || op == MATOP_MULT_TRANSPOSE_ADD) {
2226:     opAdd = (op == MATOP_MULT || op == MATOP_MULT_ADD ? MATOP_MULT_ADD : MATOP_MULT_TRANSPOSE_ADD);
2227:     for (j = 0; j < nc; j++) {
2228:       for (i = 0; i < nr; i++) {
2229:         if (!bA->m[i][j]) continue;
2230:         PetscCall(MatHasOperation(bA->m[i][j], opAdd, &flg));
2231:         if (!flg) PetscFunctionReturn(PETSC_SUCCESS);
2232:       }
2233:     }
2234:   }
2235:   if (((void **)mat->ops)[op]) *has = PETSC_TRUE;
2236:   PetscFunctionReturn(PETSC_SUCCESS);
2237: }

2239: /*MC
2240:   MATNEST -  "nest" - Matrix type consisting of nested submatrices, each stored separately.

2242:   Level: intermediate

2244:   Notes:
2245:   This matrix type permits scalable use of `PCFIELDSPLIT` and avoids the large memory costs of extracting submatrices.
2246:   It allows the use of symmetric and block formats for parts of multi-physics simulations.
2247:   It is usually used with `DMCOMPOSITE` and `DMCreateMatrix()`

2249:   Each of the submatrices lives on the same MPI communicator as the original nest matrix (though they can have zero
2250:   rows/columns on some processes.) Thus this is not meant for cases where the submatrices live on far fewer processes
2251:   than the nest matrix.

2253: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreate()`, `MatType`, `MatCreateNest()`, `MatNestSetSubMat()`, `MatNestGetSubMat()`,
2254:           `VecCreateNest()`, `DMCreateMatrix()`, `DMCOMPOSITE`, `MatNestSetVecType()`, `MatNestGetLocalISs()`,
2255:           `MatNestGetISs()`, `MatNestSetSubMats()`, `MatNestGetSubMats()`
2256: M*/
2257: PETSC_EXTERN PetscErrorCode MatCreate_Nest(Mat A)
2258: {
2259:   Mat_Nest *s;

2261:   PetscFunctionBegin;
2262:   PetscCall(PetscNew(&s));
2263:   A->data = (void *)s;

2265:   s->nr            = -1;
2266:   s->nc            = -1;
2267:   s->m             = NULL;
2268:   s->splitassembly = PETSC_FALSE;

2270:   PetscCall(PetscMemzero(A->ops, sizeof(*A->ops)));

2272:   A->ops->mult                      = MatMult_Nest;
2273:   A->ops->multadd                   = MatMultAdd_Nest;
2274:   A->ops->multtranspose             = MatMultTranspose_Nest;
2275:   A->ops->multtransposeadd          = MatMultTransposeAdd_Nest;
2276:   A->ops->transpose                 = MatTranspose_Nest;
2277:   A->ops->multhermitiantranspose    = MatMultHermitianTranspose_Nest;
2278:   A->ops->multhermitiantransposeadd = MatMultHermitianTransposeAdd_Nest;
2279:   A->ops->assemblybegin             = MatAssemblyBegin_Nest;
2280:   A->ops->assemblyend               = MatAssemblyEnd_Nest;
2281:   A->ops->zeroentries               = MatZeroEntries_Nest;
2282:   A->ops->copy                      = MatCopy_Nest;
2283:   A->ops->axpy                      = MatAXPY_Nest;
2284:   A->ops->duplicate                 = MatDuplicate_Nest;
2285:   A->ops->createsubmatrix           = MatCreateSubMatrix_Nest;
2286:   A->ops->destroy                   = MatDestroy_Nest;
2287:   A->ops->view                      = MatView_Nest;
2288:   A->ops->getvecs                   = NULL; /* Use VECNEST by calling MatNestSetVecType(A,VECNEST) */
2289:   A->ops->getlocalsubmatrix         = MatGetLocalSubMatrix_Nest;
2290:   A->ops->restorelocalsubmatrix     = MatRestoreLocalSubMatrix_Nest;
2291:   A->ops->getdiagonal               = MatGetDiagonal_Nest;
2292:   A->ops->diagonalscale             = MatDiagonalScale_Nest;
2293:   A->ops->scale                     = MatScale_Nest;
2294:   A->ops->shift                     = MatShift_Nest;
2295:   A->ops->diagonalset               = MatDiagonalSet_Nest;
2296:   A->ops->setrandom                 = MatSetRandom_Nest;
2297:   A->ops->hasoperation              = MatHasOperation_Nest;

2299:   A->spptr     = NULL;
2300:   A->assembled = PETSC_FALSE;

2302:   /* expose Nest api's */
2303:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMat_C", MatNestGetSubMat_Nest));
2304:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMat_C", MatNestSetSubMat_Nest));
2305:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMats_C", MatNestGetSubMats_Nest));
2306:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSize_C", MatNestGetSize_Nest));
2307:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetISs_C", MatNestGetISs_Nest));
2308:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetLocalISs_C", MatNestGetLocalISs_Nest));
2309:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetVecType_C", MatNestSetVecType_Nest));
2310:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMats_C", MatNestSetSubMats_Nest));
2311:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpiaij_C", MatConvert_Nest_AIJ));
2312:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqaij_C", MatConvert_Nest_AIJ));
2313:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_aij_C", MatConvert_Nest_AIJ));
2314:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_is_C", MatConvert_Nest_IS));
2315:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpidense_C", MatConvert_Nest_Dense));
2316:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqdense_C", MatConvert_Nest_Dense));
2317:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_seqdense_C", MatProductSetFromOptions_Nest_Dense));
2318:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_mpidense_C", MatProductSetFromOptions_Nest_Dense));

2320:   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATNEST));
2321:   PetscFunctionReturn(PETSC_SUCCESS);
2322: }