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;

 17:   PetscFunctionBegin;
 18:   *m = *n = *M = *N = 0;
 19:   for (PetscInt i = 0; i < bA->nr; i++) { /* rows */
 20:     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 (PetscInt j = 0; j < bA->nc; j++) { /* cols */
 28:     PetscInt sn, sN;

 30:     PetscCall(ISGetLocalSize(bA->isglobal.col[j], &sn));
 31:     PetscCall(ISGetSize(bA->isglobal.col[j], &sN));
 32:     *n += sn;
 33:     *N += sN;
 34:   }
 35:   PetscFunctionReturn(PETSC_SUCCESS);
 36: }

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

 44:   PetscFunctionBegin;
 45:   for (PetscInt i = 0; i < bA->nr; i++) PetscCall(VecGetSubVector(y, bA->isglobal.row[i], &by[i]));
 46:   for (PetscInt i = 0; i < bA->nc; i++) PetscCall(VecGetSubVector(x, bA->isglobal.col[i], &bx[i]));
 47:   for (PetscInt i = 0; i < bA->nr; i++) {
 48:     PetscCall(VecZeroEntries(by[i]));
 49:     for (PetscInt j = 0; j < bA->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 (PetscInt i = 0; i < bA->nr; i++) PetscCall(VecRestoreSubVector(y, bA->isglobal.row[i], &by[i]));
 56:   for (PetscInt i = 0; i < bA->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;

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

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

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

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

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

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

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

154: static PetscErrorCode MatNest_DenseDestroy(PetscCtxRt ctx)
155: {
156:   Nest_Dense *contents = *(Nest_Dense **)ctx;

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

166: static PetscErrorCode MatProductSymbolic_Nest_Dense(Mat C)
167: {
168:   Mat_Nest          *bA;
169:   Mat                viewB, workC;
170:   const PetscScalar *barray;
171:   PetscInt           M, N, m, n, nr, nc, maxm = 0, ldb;
172:   Nest_Dense        *contents = NULL;
173:   PetscBool          cisdense;
174:   Mat                A, B;
175:   PetscReal          fill;

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

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

226:       PetscCall(MatProductCreate(bA->m[i][j], viewB, NULL, &contents->workC[i * nc + j]));
227:       workC = contents->workC[i * nc + j];
228:       PetscCall(MatProductSetType(workC, MATPRODUCT_AB));
229:       PetscCall(MatProductSetAlgorithm(workC, "default"));
230:       PetscCall(MatProductSetFill(workC, fill));
231:       PetscCall(MatProductSetFromOptions(workC));
232:       PetscCall(MatProductSymbolic(workC));

234:       /* since tarray will be shared by all Mat */
235:       PetscCall(MatSeqDenseSetPreallocation(workC, contents->tarray));
236:       PetscCall(MatMPIDenseSetPreallocation(workC, contents->tarray));
237:     }
238:     PetscCall(MatDestroy(&viewB));
239:   }
240:   PetscCall(MatDenseRestoreArrayRead(B, &barray));

242:   C->ops->productnumeric = MatProductNumeric_Nest_Dense;
243:   PetscFunctionReturn(PETSC_SUCCESS);
244: }

246: static PetscErrorCode MatProductSetFromOptions_Nest_Dense(Mat C)
247: {
248:   Mat_Product *product = C->product;

250:   PetscFunctionBegin;
251:   if (product->type == MATPRODUCT_AB) C->ops->productsymbolic = MatProductSymbolic_Nest_Dense;
252:   PetscFunctionReturn(PETSC_SUCCESS);
253: }

255: static PetscErrorCode MatMultTransposeKernel_Nest(Mat A, Vec x, Vec y, PetscBool herm)
256: {
257:   Mat_Nest *bA = (Mat_Nest *)A->data;
258:   Vec      *bx = bA->left, *by = bA->right;

260:   PetscFunctionBegin;
261:   for (PetscInt i = 0; i < bA->nr; i++) PetscCall(VecGetSubVector(x, bA->isglobal.row[i], &bx[i]));
262:   for (PetscInt i = 0; i < bA->nc; i++) PetscCall(VecGetSubVector(y, bA->isglobal.col[i], &by[i]));
263:   for (PetscInt j = 0; j < bA->nc; j++) {
264:     PetscCall(VecZeroEntries(by[j]));
265:     for (PetscInt i = 0; i < bA->nr; i++) {
266:       if (!bA->m[i][j]) continue;
267:       if (herm) PetscCall(MatMultHermitianTransposeAdd(bA->m[i][j], bx[i], by[j], by[j])); /* y[j] <- y[j] + (A[i][j])^H * x[i] */
268:       else PetscCall(MatMultTransposeAdd(bA->m[i][j], bx[i], by[j], by[j]));               /* y[j] <- y[j] + (A[i][j])^T * x[i] */
269:     }
270:   }
271:   for (PetscInt i = 0; i < bA->nr; i++) PetscCall(VecRestoreSubVector(x, bA->isglobal.row[i], &bx[i]));
272:   for (PetscInt i = 0; i < bA->nc; i++) PetscCall(VecRestoreSubVector(y, bA->isglobal.col[i], &by[i]));
273:   PetscFunctionReturn(PETSC_SUCCESS);
274: }

276: static PetscErrorCode MatMultTranspose_Nest(Mat A, Vec x, Vec y)
277: {
278:   PetscFunctionBegin;
279:   PetscCall(MatMultTransposeKernel_Nest(A, x, y, PETSC_FALSE));
280:   PetscFunctionReturn(PETSC_SUCCESS);
281: }

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

290: static PetscErrorCode MatMultTransposeAddKernel_Nest(Mat A, Vec x, Vec y, Vec z, PetscBool herm)
291: {
292:   Mat_Nest *bA = (Mat_Nest *)A->data;
293:   Vec      *bx = bA->left, *bz = bA->right;

295:   PetscFunctionBegin;
296:   for (PetscInt i = 0; i < bA->nr; i++) PetscCall(VecGetSubVector(x, bA->isglobal.row[i], &bx[i]));
297:   for (PetscInt i = 0; i < bA->nc; i++) PetscCall(VecGetSubVector(z, bA->isglobal.col[i], &bz[i]));
298:   for (PetscInt j = 0; j < bA->nc; j++) {
299:     if (y != z) {
300:       Vec by;

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

317: static PetscErrorCode MatMultTransposeAdd_Nest(Mat A, Vec x, Vec y, Vec z)
318: {
319:   PetscFunctionBegin;
320:   PetscCall(MatMultTransposeAddKernel_Nest(A, x, y, z, PETSC_FALSE));
321:   PetscFunctionReturn(PETSC_SUCCESS);
322: }

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

331: static PetscErrorCode MatTranspose_Nest(Mat A, MatReuse reuse, Mat *B)
332: {
333:   Mat_Nest *bA = (Mat_Nest *)A->data, *bC;
334:   Mat       C;
335:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

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

341:   if (reuse == MAT_INITIAL_MATRIX || reuse == MAT_INPLACE_MATRIX) {
342:     Mat *subs;
343:     IS  *is_row, *is_col;

345:     PetscCall(PetscCalloc1(nr * nc, &subs));
346:     PetscCall(PetscMalloc2(nr, &is_row, nc, &is_col));
347:     PetscCall(MatNestGetISs(A, is_row, is_col));
348:     if (reuse == MAT_INPLACE_MATRIX) {
349:       for (i = 0; i < nr; i++) {
350:         for (j = 0; j < nc; j++) subs[i + nr * j] = bA->m[i][j];
351:       }
352:     }

354:     PetscCall(MatCreateNest(PetscObjectComm((PetscObject)A), nc, is_col, nr, is_row, subs, &C));
355:     PetscCall(PetscFree(subs));
356:     PetscCall(PetscFree2(is_row, is_col));
357:   } else {
358:     C = *B;
359:   }

361:   bC = (Mat_Nest *)C->data;
362:   for (i = 0; i < nr; i++) {
363:     for (j = 0; j < nc; j++) {
364:       if (bA->m[i][j]) {
365:         PetscCall(MatTranspose(bA->m[i][j], reuse, &bC->m[j][i]));
366:       } else {
367:         bC->m[j][i] = NULL;
368:       }
369:     }
370:   }

372:   if (reuse == MAT_INITIAL_MATRIX || reuse == MAT_REUSE_MATRIX) {
373:     *B = C;
374:   } else {
375:     PetscCall(MatHeaderMerge(A, &C));
376:   }
377:   PetscFunctionReturn(PETSC_SUCCESS);
378: }

380: static PetscErrorCode MatNestDestroyISList(PetscInt n, IS **list)
381: {
382:   IS *lst = *list;

384:   PetscFunctionBegin;
385:   if (!lst) PetscFunctionReturn(PETSC_SUCCESS);
386:   for (PetscInt i = 0; i < n; i++) PetscCall(ISDestroy(&lst[i]));
387:   PetscCall(PetscFree(lst));
388:   *list = NULL;
389:   PetscFunctionReturn(PETSC_SUCCESS);
390: }

392: static PetscErrorCode MatReset_Nest(Mat A)
393: {
394:   Mat_Nest *vs = (Mat_Nest *)A->data;

396:   PetscFunctionBegin;
397:   /* release the matrices and the place holders */
398:   PetscCall(MatNestDestroyISList(vs->nr, &vs->isglobal.row));
399:   PetscCall(MatNestDestroyISList(vs->nc, &vs->isglobal.col));
400:   PetscCall(MatNestDestroyISList(vs->nr, &vs->islocal.row));
401:   PetscCall(MatNestDestroyISList(vs->nc, &vs->islocal.col));

403:   PetscCall(PetscFree(vs->row_len));
404:   PetscCall(PetscFree(vs->col_len));
405:   PetscCall(PetscFree(vs->nnzstate));

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

409:   /* release the matrices and the place holders */
410:   if (vs->m) {
411:     for (PetscInt i = 0; i < vs->nr; i++) {
412:       for (PetscInt j = 0; j < vs->nc; j++) PetscCall(MatDestroy(&vs->m[i][j]));
413:     }
414:     PetscCall(PetscFree(vs->m[0]));
415:     PetscCall(PetscFree(vs->m));
416:   }

418:   /* restore defaults */
419:   vs->nr            = 0;
420:   vs->nc            = 0;
421:   vs->splitassembly = PETSC_FALSE;
422:   PetscFunctionReturn(PETSC_SUCCESS);
423: }

425: static PetscErrorCode MatDestroy_Nest(Mat A)
426: {
427:   PetscFunctionBegin;
428:   PetscCall(MatReset_Nest(A));
429:   PetscCall(PetscFree(A->data));
430:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMat_C", NULL));
431:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMat_C", NULL));
432:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMats_C", NULL));
433:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSize_C", NULL));
434:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetISs_C", NULL));
435:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetLocalISs_C", NULL));
436:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetVecType_C", NULL));
437:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMats_C", NULL));
438:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpiaij_C", NULL));
439:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqaij_C", NULL));
440:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_aij_C", NULL));
441:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_is_C", NULL));
442:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpidense_C", NULL));
443:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqdense_C", NULL));
444:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_seqdense_C", NULL));
445:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_mpidense_C", NULL));
446:   PetscFunctionReturn(PETSC_SUCCESS);
447: }

449: static PetscErrorCode MatAssemblyBegin_Nest(Mat A, MatAssemblyType type)
450: {
451:   Mat_Nest *vs       = (Mat_Nest *)A->data;
452:   PetscBool nnzstate = PETSC_FALSE;

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

479: static PetscErrorCode MatAssemblyEnd_Nest(Mat A, MatAssemblyType type)
480: {
481:   Mat_Nest *vs = (Mat_Nest *)A->data;

483:   PetscFunctionBegin;
484:   for (PetscInt i = 0; i < vs->nr; i++) {
485:     for (PetscInt j = 0; j < vs->nc; j++) {
486:       if (vs->m[i][j]) {
487:         if (vs->splitassembly) PetscCall(MatAssemblyEnd(vs->m[i][j], type));
488:       }
489:     }
490:   }
491:   PetscFunctionReturn(PETSC_SUCCESS);
492: }

494: static PetscErrorCode MatNestFindNonzeroSubMatRow(Mat A, PetscInt row, Mat *B)
495: {
496:   Mat_Nest *vs = (Mat_Nest *)A->data;
497:   Mat       sub;

499:   PetscFunctionBegin;
500:   sub = (row < vs->nc) ? vs->m[row][row] : (Mat)NULL; /* Prefer to find on the diagonal */
501:   for (PetscInt j = 0; !sub && j < vs->nc; j++) sub = vs->m[row][j];
502:   if (sub) PetscCall(MatSetUp(sub)); /* Ensure that the sizes are available */
503:   *B = sub;
504:   PetscFunctionReturn(PETSC_SUCCESS);
505: }

507: static PetscErrorCode MatNestFindNonzeroSubMatCol(Mat A, PetscInt col, Mat *B)
508: {
509:   Mat_Nest *vs = (Mat_Nest *)A->data;
510:   Mat       sub;

512:   PetscFunctionBegin;
513:   sub = (col < vs->nr) ? vs->m[col][col] : (Mat)NULL; /* Prefer to find on the diagonal */
514:   for (PetscInt i = 0; !sub && i < vs->nr; i++) sub = vs->m[i][col];
515:   if (sub) PetscCall(MatSetUp(sub)); /* Ensure that the sizes are available */
516:   *B = sub;
517:   PetscFunctionReturn(PETSC_SUCCESS);
518: }

520: static PetscErrorCode MatNestFindISRange(Mat A, PetscInt n, const IS list[], IS is, PetscInt *begin, PetscInt *end)
521: {
522:   PetscInt  i, j, size, m;
523:   PetscBool flg;
524:   IS        out, concatenate[2];

526:   PetscFunctionBegin;
527:   PetscAssertPointer(list, 3);
529:   if (begin) {
530:     PetscAssertPointer(begin, 5);
531:     *begin = -1;
532:   }
533:   if (end) {
534:     PetscAssertPointer(end, 6);
535:     *end = -1;
536:   }
537:   for (i = 0; i < n; i++) {
538:     if (!list[i]) continue;
539:     PetscCall(ISEqualUnsorted(list[i], is, &flg));
540:     if (flg) {
541:       if (begin) *begin = i;
542:       if (end) *end = i + 1;
543:       PetscFunctionReturn(PETSC_SUCCESS);
544:     }
545:   }
546:   PetscCall(ISGetSize(is, &size));
547:   for (i = 0; i < n - 1; i++) {
548:     if (!list[i]) continue;
549:     m = 0;
550:     PetscCall(ISConcatenate(PetscObjectComm((PetscObject)A), 2, list + i, &out));
551:     PetscCall(ISGetSize(out, &m));
552:     for (j = i + 2; j < n && m < size; j++) {
553:       if (list[j]) {
554:         concatenate[0] = out;
555:         concatenate[1] = list[j];
556:         PetscCall(ISConcatenate(PetscObjectComm((PetscObject)A), 2, concatenate, &out));
557:         PetscCall(ISDestroy(concatenate));
558:         PetscCall(ISGetSize(out, &m));
559:       }
560:     }
561:     if (m == size) {
562:       PetscCall(ISEqualUnsorted(out, is, &flg));
563:       if (flg) {
564:         if (begin) *begin = i;
565:         if (end) *end = j;
566:         PetscCall(ISDestroy(&out));
567:         PetscFunctionReturn(PETSC_SUCCESS);
568:       }
569:     }
570:     PetscCall(ISDestroy(&out));
571:   }
572:   PetscFunctionReturn(PETSC_SUCCESS);
573: }

575: static PetscErrorCode MatNestFillEmptyMat_Private(Mat A, PetscInt i, PetscInt j, Mat *B)
576: {
577:   Mat_Nest *vs = (Mat_Nest *)A->data;
578:   PetscInt  lr, lc;

580:   PetscFunctionBegin;
581:   PetscCall(MatCreate(PetscObjectComm((PetscObject)A), B));
582:   PetscCall(ISGetLocalSize(vs->isglobal.row[i], &lr));
583:   PetscCall(ISGetLocalSize(vs->isglobal.col[j], &lc));
584:   PetscCall(MatSetSizes(*B, lr, lc, PETSC_DECIDE, PETSC_DECIDE));
585:   PetscCall(MatSetType(*B, MATAIJ));
586:   PetscCall(MatSeqAIJSetPreallocation(*B, 0, NULL));
587:   PetscCall(MatMPIAIJSetPreallocation(*B, 0, NULL, 0, NULL));
588:   PetscCall(MatSetUp(*B));
589:   PetscCall(MatSetOption(*B, MAT_NO_OFF_PROC_ENTRIES, PETSC_TRUE));
590:   PetscCall(MatAssemblyBegin(*B, MAT_FINAL_ASSEMBLY));
591:   PetscCall(MatAssemblyEnd(*B, MAT_FINAL_ASSEMBLY));
592:   PetscFunctionReturn(PETSC_SUCCESS);
593: }

595: static PetscErrorCode MatNestGetBlock_Private(Mat A, PetscInt rbegin, PetscInt rend, PetscInt cbegin, PetscInt cend, Mat *B)
596: {
597:   Mat_Nest  *vs = (Mat_Nest *)A->data;
598:   Mat       *a;
599:   PetscInt   i, j, k, l, nr = rend - rbegin, nc = cend - cbegin;
600:   char       keyname[256];
601:   PetscBool *b;
602:   PetscBool  flg;

604:   PetscFunctionBegin;
605:   *B = NULL;
606:   PetscCall(PetscSNPrintf(keyname, sizeof(keyname), "NestBlock_%" PetscInt_FMT "-%" PetscInt_FMT "x%" PetscInt_FMT "-%" PetscInt_FMT, rbegin, rend, cbegin, cend));
607:   PetscCall(PetscObjectQuery((PetscObject)A, keyname, (PetscObject *)B));
608:   if (*B) PetscFunctionReturn(PETSC_SUCCESS);

610:   PetscCall(PetscMalloc2(nr * nc, &a, nr * nc, &b));
611:   for (i = 0; i < nr; i++) {
612:     for (j = 0; j < nc; j++) {
613:       a[i * nc + j] = vs->m[rbegin + i][cbegin + j];
614:       b[i * nc + j] = PETSC_FALSE;
615:     }
616:   }
617:   if (nc != vs->nc && nr != vs->nr) {
618:     for (i = 0; i < nr; i++) {
619:       for (j = 0; j < nc; j++) {
620:         flg = PETSC_FALSE;
621:         for (k = 0; (k < nr && !flg); k++) {
622:           if (a[j + k * nc]) flg = PETSC_TRUE;
623:         }
624:         if (flg) {
625:           flg = PETSC_FALSE;
626:           for (l = 0; (l < nc && !flg); l++) {
627:             if (a[i * nc + l]) flg = PETSC_TRUE;
628:           }
629:         }
630:         if (!flg) {
631:           b[i * nc + j] = PETSC_TRUE;
632:           PetscCall(MatNestFillEmptyMat_Private(A, rbegin + i, cbegin + j, a + i * nc + j));
633:         }
634:       }
635:     }
636:   }
637:   PetscCall(MatCreateNest(PetscObjectComm((PetscObject)A), nr, nr != vs->nr ? NULL : vs->isglobal.row, nc, nc != vs->nc ? NULL : vs->isglobal.col, a, B));
638:   for (i = 0; i < nr; i++) {
639:     for (j = 0; j < nc; j++) {
640:       if (b[i * nc + j]) PetscCall(MatDestroy(a + i * nc + j));
641:     }
642:   }
643:   PetscCall(PetscFree2(a, b));
644:   (*B)->assembled = A->assembled;
645:   PetscCall(PetscObjectCompose((PetscObject)A, keyname, (PetscObject)*B));
646:   PetscCall(PetscObjectDereference((PetscObject)*B)); /* Leave the only remaining reference in the composition */
647:   PetscFunctionReturn(PETSC_SUCCESS);
648: }

650: static PetscErrorCode MatNestFindSubMat(Mat A, IS isrow, IS iscol, PetscBool global, PetscBool *found, Mat *B)
651: {
652:   Mat_Nest *vs = (Mat_Nest *)A->data;
653:   PetscInt  rbegin, rend, cbegin, cend;

655:   PetscFunctionBegin;
656:   *B = NULL;
657:   PetscCall(MatNestFindISRange(A, vs->nr, global ? vs->isglobal.row : vs->islocal.row, isrow, &rbegin, &rend));
658:   PetscCall(MatNestFindISRange(A, vs->nc, global ? vs->isglobal.col : vs->islocal.col, iscol, &cbegin, &cend));
659:   if (rend == rbegin + 1 && cend == cbegin + 1) {
660:     if (!vs->m[rbegin][cbegin]) PetscCall(MatNestFillEmptyMat_Private(A, rbegin, cbegin, vs->m[rbegin] + cbegin));
661:     *B = vs->m[rbegin][cbegin];
662:     if (found) *found = PETSC_TRUE;
663:   } else if (rbegin != -1 && cbegin != -1) {
664:     PetscCheck(global == PETSC_TRUE, PETSC_COMM_SELF, PETSC_ERR_SUP, "MATNEST local submatrix cannot select more than a single submatrix");
665:     PetscCall(MatNestGetBlock_Private(A, rbegin, rend, cbegin, cend, B));
666:     if (found) *found = PETSC_TRUE;
667:   } else if (found) *found = PETSC_FALSE;
668:   PetscFunctionReturn(PETSC_SUCCESS);
669: }

671: static PetscErrorCode MatNestFindFullBlocks_Private(Mat A, PetscInt n, const IS blockis[], IS is, const char axis[], PetscInt *nselected, PetscInt **selected, IS **isout)
672: {
673:   const PetscInt *idx;
674:   PetscInt       *blocks;
675:   IS             *out;
676:   PetscInt        N, bs, cursor = 0, i, nblock, nlocal, nout = 0, offset = 0, start;
677:   PetscBool       complete, match;

679:   PetscFunctionBegin;
680:   PetscCall(ISGetSize(is, &N));
681:   PetscCheck(N, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Empty %s index sets are not supported for MATNEST submatrices", axis);
682:   PetscCall(ISGetLocalSize(is, &nlocal));
683:   PetscCall(ISGetIndices(is, &idx));
684:   PetscCall(PetscMalloc1(n, &blocks));
685:   for (i = 0; i < n; i++) {
686:     const PetscInt *bidx;

688:     PetscCall(ISGetSize(blockis[i], &N));
689:     if (!N) continue;
690:     PetscCall(ISGetLocalSize(blockis[i], &nblock));
691:     match = (PetscBool)(cursor + nblock <= nlocal);
692:     if (match && nblock) {
693:       PetscCall(ISGetIndices(blockis[i], &bidx));
694:       PetscCall(PetscArraycmp(idx + cursor, bidx, nblock, &match));
695:       PetscCall(ISRestoreIndices(blockis[i], &bidx));
696:     }
697:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &match, 1, MPI_C_BOOL, MPI_LAND, PetscObjectComm((PetscObject)A)));
698:     if (match) {
699:       blocks[nout++] = i;
700:       cursor += nblock;
701:     }
702:   }
703:   complete = (PetscBool)(cursor == nlocal);
704:   PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, &complete, 1, MPI_C_BOOL, MPI_LAND, PetscObjectComm((PetscObject)A)));
705:   PetscCall(ISRestoreIndices(is, &idx));
706:   if (!complete || !nout) PetscCall(PetscFree(blocks));
707:   PetscCheck(complete && nout, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "MATNEST submatrix %s index set must be an ordered union of complete MATNEST blocks", axis);

709:   PetscCallMPI(MPI_Scan(&nlocal, &start, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)A)));
710:   start -= nlocal;
711:   PetscCall(PetscMalloc1(nout, &out));
712:   for (i = 0; i < nout; i++) {
713:     PetscCall(ISGetLocalSize(blockis[blocks[i]], &nblock));
714:     PetscCall(ISGetBlockSize(blockis[blocks[i]], &bs));
715:     PetscCall(ISCreateStride(PetscObjectComm((PetscObject)A), nblock, start + offset, 1, out + i));
716:     PetscCall(ISSetBlockSize(out[i], bs));
717:     offset += nblock;
718:   }
719:   PetscCheck(offset == nlocal, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Inconsistent MATNEST submatrix %s layout", axis);
720:   *nselected = nout;
721:   *selected  = blocks;
722:   *isout     = out;
723:   PetscFunctionReturn(PETSC_SUCCESS);
724: }

726: static PetscErrorCode MatCreateSubMatrix_Nest_Nontrivial(Mat A, IS isrow, IS iscol, MatReuse reuse, Mat *B)
727: {
728:   Mat_Nest *vs = (Mat_Nest *)A->data;
729:   Mat      *submats;
730:   IS       *rowis, *colis;
731:   PetscInt *rows, *cols;
732:   PetscInt  nr, nc;
733:   PetscBool flg;

735:   PetscFunctionBegin;
736:   PetscCall(MatNestFindFullBlocks_Private(A, vs->nr, vs->isglobal.row, isrow, "row", &nr, &rows, &rowis));
737:   PetscCall(MatNestFindFullBlocks_Private(A, vs->nc, vs->isglobal.col, iscol, "column", &nc, &cols, &colis));
738:   PetscCall(PetscMalloc1(nr * nc, &submats));
739:   for (PetscInt i = 0; i < nr; i++) {
740:     for (PetscInt j = 0; j < nc; j++) submats[i * nc + j] = vs->m[rows[i]][cols[j]];
741:   }
742:   if (reuse == MAT_INITIAL_MATRIX) {
743:     PetscCall(MatCreateNest(PetscObjectComm((PetscObject)A), nr, rowis, nc, colis, submats, B));
744:     (*B)->assembled = A->assembled;
745:   } else {
746:     PetscCheck(reuse == MAT_REUSE_MATRIX, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Invalid MatReuse %d", (int)reuse);
747:     PetscCall(PetscObjectTypeCompare((PetscObject)*B, MATNEST, &flg));
748:     PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Cannot reuse a non-MATNEST matrix for this MATNEST submatrix");
749:     vs = (Mat_Nest *)(*B)->data;
750:     PetscCheck(vs->nr == nr && vs->nc == nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Cannot reuse MATNEST submatrix with a different block layout");
751:     for (PetscInt i = 0; i < nr; i++) {
752:       PetscCall(ISEqualUnsorted(vs->isglobal.row[i], rowis[i], &flg));
753:       PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Cannot reuse MATNEST submatrix with a different row layout");
754:     }
755:     for (PetscInt j = 0; j < nc; j++) {
756:       PetscCall(ISEqualUnsorted(vs->isglobal.col[j], colis[j], &flg));
757:       PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Cannot reuse MATNEST submatrix with a different column layout");
758:     }
759:     PetscCall(MatNestSetSubMats(*B, nr, rowis, nc, colis, submats));
760:     (*B)->assembled = A->assembled;
761:   }
762:   PetscCall(PetscFree(submats));
763:   for (PetscInt i = 0; i < nr; i++) PetscCall(ISDestroy(rowis + i));
764:   for (PetscInt j = 0; j < nc; j++) PetscCall(ISDestroy(colis + j));
765:   PetscCall(PetscFree(rows));
766:   PetscCall(PetscFree(rowis));
767:   PetscCall(PetscFree(cols));
768:   PetscCall(PetscFree(colis));
769:   PetscFunctionReturn(PETSC_SUCCESS);
770: }

772: /*
773:    TODO: This does not actually returns a submatrix we can modify
774: */
775: static PetscErrorCode MatCreateSubMatrix_Nest(Mat A, IS isrow, IS iscol, MatReuse reuse, Mat *B)
776: {
777:   Mat       sub;
778:   PetscBool found;

780:   PetscFunctionBegin;
781:   PetscCall(MatNestFindSubMat(A, isrow, iscol, PETSC_TRUE, &found, &sub));
782:   if (!found) {
783:     PetscCall(MatCreateSubMatrix_Nest_Nontrivial(A, isrow, iscol, reuse, B));
784:     PetscFunctionReturn(PETSC_SUCCESS);
785:   }
786:   switch (reuse) {
787:   case MAT_INITIAL_MATRIX:
788:     PetscCall(PetscObjectReference((PetscObject)sub));
789:     if (sub) PetscCall(PetscObjectStateIncrease((PetscObject)sub));
790:     *B = sub;
791:     break;
792:   case MAT_REUSE_MATRIX:
793:     PetscCheck(sub == *B, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Submatrix was not used before in this call");
794:     if (sub) PetscCall(PetscObjectStateIncrease((PetscObject)sub));
795:     break;
796:   default:
797:     break;
798:   }
799:   PetscFunctionReturn(PETSC_SUCCESS);
800: }

802: static PetscErrorCode MatGetLocalSubMatrix_Nest(Mat A, IS isrow, IS iscol, Mat *B)
803: {
804:   Mat sub;

806:   PetscFunctionBegin;
807:   PetscCall(MatNestFindSubMat(A, isrow, iscol, PETSC_FALSE, NULL, &sub));
808:   /* We allow the submatrix to be NULL, perhaps it would be better for the user to return an empty matrix instead */
809:   PetscCall(PetscObjectReference((PetscObject)sub));
810:   *B = sub;
811:   PetscFunctionReturn(PETSC_SUCCESS);
812: }

814: static PetscErrorCode MatRestoreLocalSubMatrix_Nest(Mat A, IS isrow, IS iscol, Mat *B)
815: {
816:   Mat sub;

818:   PetscFunctionBegin;
819:   PetscCall(MatNestFindSubMat(A, isrow, iscol, PETSC_FALSE, NULL, &sub));
820:   PetscCheck(*B == sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Local submatrix has not been gotten");
821:   if (sub) {
822:     PetscCheck(((PetscObject)sub)->refct > 1, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Local submatrix has had reference count decremented too many times");
823:     PetscCall(MatDestroy(B));
824:   }
825:   PetscFunctionReturn(PETSC_SUCCESS);
826: }

828: static PetscErrorCode MatGetDiagonal_Nest(Mat A, Vec v)
829: {
830:   Mat_Nest *bA = (Mat_Nest *)A->data;

832:   PetscFunctionBegin;
833:   for (PetscInt i = 0; i < bA->nr; i++) {
834:     Vec bv;
835:     PetscCall(VecGetSubVector(v, bA->isglobal.row[i], &bv));
836:     if (bA->m[i][i]) PetscCall(MatGetDiagonal(bA->m[i][i], bv));
837:     else PetscCall(VecSet(bv, 0.0));
838:     PetscCall(VecRestoreSubVector(v, bA->isglobal.row[i], &bv));
839:   }
840:   PetscFunctionReturn(PETSC_SUCCESS);
841: }

843: static PetscErrorCode MatDiagonalScale_Nest(Mat A, Vec l, Vec r)
844: {
845:   Mat_Nest *bA = (Mat_Nest *)A->data;
846:   Vec       bl, *br;

848:   PetscFunctionBegin;
849:   PetscCall(PetscCalloc1(bA->nc, &br));
850:   if (r) {
851:     for (PetscInt j = 0; j < bA->nc; j++) PetscCall(VecGetSubVector(r, bA->isglobal.col[j], &br[j]));
852:   }
853:   bl = NULL;
854:   for (PetscInt i = 0; i < bA->nr; i++) {
855:     if (l) PetscCall(VecGetSubVector(l, bA->isglobal.row[i], &bl));
856:     for (PetscInt j = 0; j < bA->nc; j++) {
857:       if (bA->m[i][j]) PetscCall(MatDiagonalScale(bA->m[i][j], bl, br[j]));
858:     }
859:     if (l) PetscCall(VecRestoreSubVector(l, bA->isglobal.row[i], &bl));
860:   }
861:   if (r) {
862:     for (PetscInt j = 0; j < bA->nc; j++) PetscCall(VecRestoreSubVector(r, bA->isglobal.col[j], &br[j]));
863:   }
864:   PetscCall(PetscFree(br));
865:   PetscFunctionReturn(PETSC_SUCCESS);
866: }

868: static PetscErrorCode MatScale_Nest(Mat A, PetscScalar a)
869: {
870:   Mat_Nest *bA = (Mat_Nest *)A->data;

872:   PetscFunctionBegin;
873:   for (PetscInt i = 0; i < bA->nr; i++) {
874:     for (PetscInt j = 0; j < bA->nc; j++) {
875:       if (bA->m[i][j]) PetscCall(MatScale(bA->m[i][j], a));
876:     }
877:   }
878:   PetscFunctionReturn(PETSC_SUCCESS);
879: }

881: static PetscErrorCode MatShift_Nest(Mat A, PetscScalar a)
882: {
883:   Mat_Nest *bA       = (Mat_Nest *)A->data;
884:   PetscBool nnzstate = PETSC_FALSE;

886:   PetscFunctionBegin;
887:   for (PetscInt i = 0; i < bA->nr; i++) {
888:     PetscObjectState subnnzstate = 0;
889:     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);
890:     PetscCall(MatShift(bA->m[i][i], a));
891:     PetscCall(MatGetNonzeroState(bA->m[i][i], &subnnzstate));
892:     nnzstate                     = (PetscBool)(nnzstate || bA->nnzstate[i * bA->nc + i] != subnnzstate);
893:     bA->nnzstate[i * bA->nc + i] = subnnzstate;
894:   }
895:   if (nnzstate) A->nonzerostate++;
896:   PetscFunctionReturn(PETSC_SUCCESS);
897: }

899: static PetscErrorCode MatDiagonalSet_Nest(Mat A, Vec D, InsertMode is)
900: {
901:   Mat_Nest *bA       = (Mat_Nest *)A->data;
902:   PetscBool nnzstate = PETSC_FALSE;

904:   PetscFunctionBegin;
905:   for (PetscInt i = 0; i < bA->nr; i++) {
906:     PetscObjectState subnnzstate = 0;
907:     Vec              bv;
908:     PetscCall(VecGetSubVector(D, bA->isglobal.row[i], &bv));
909:     if (bA->m[i][i]) {
910:       PetscCall(MatDiagonalSet(bA->m[i][i], bv, is));
911:       PetscCall(MatGetNonzeroState(bA->m[i][i], &subnnzstate));
912:     }
913:     PetscCall(VecRestoreSubVector(D, bA->isglobal.row[i], &bv));
914:     nnzstate                     = (PetscBool)(nnzstate || bA->nnzstate[i * bA->nc + i] != subnnzstate);
915:     bA->nnzstate[i * bA->nc + i] = subnnzstate;
916:   }
917:   if (nnzstate) A->nonzerostate++;
918:   PetscFunctionReturn(PETSC_SUCCESS);
919: }

921: static PetscErrorCode MatSetRandom_Nest(Mat A, PetscRandom rctx)
922: {
923:   Mat_Nest *bA = (Mat_Nest *)A->data;

925:   PetscFunctionBegin;
926:   for (PetscInt i = 0; i < bA->nr; i++) {
927:     for (PetscInt j = 0; j < bA->nc; j++) {
928:       if (bA->m[i][j]) PetscCall(MatSetRandom(bA->m[i][j], rctx));
929:     }
930:   }
931:   PetscFunctionReturn(PETSC_SUCCESS);
932: }

934: static PetscErrorCode MatCreateVecs_Nest(Mat A, Vec *right, Vec *left)
935: {
936:   Mat_Nest *bA = (Mat_Nest *)A->data;
937:   Vec      *L, *R;
938:   MPI_Comm  comm;
939:   PetscInt  i, j;

941:   PetscFunctionBegin;
942:   PetscCall(PetscObjectGetComm((PetscObject)A, &comm));
943:   if (right) {
944:     /* allocate R */
945:     PetscCall(PetscMalloc1(bA->nc, &R));
946:     /* Create the right vectors */
947:     for (j = 0; j < bA->nc; j++) {
948:       for (i = 0; i < bA->nr; i++) {
949:         if (bA->m[i][j]) {
950:           PetscCall(MatCreateVecs(bA->m[i][j], &R[j], NULL));
951:           break;
952:         }
953:       }
954:       PetscCheck(i != bA->nr, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Mat(Nest) contains a null column.");
955:     }
956:     PetscCall(VecCreateNest(comm, bA->nc, bA->isglobal.col, R, right));
957:     /* hand back control to the nest vector */
958:     for (j = 0; j < bA->nc; j++) PetscCall(VecDestroy(&R[j]));
959:     PetscCall(PetscFree(R));
960:   }

962:   if (left) {
963:     /* allocate L */
964:     PetscCall(PetscMalloc1(bA->nr, &L));
965:     /* Create the left vectors */
966:     for (i = 0; i < bA->nr; i++) {
967:       for (j = 0; j < bA->nc; j++) {
968:         if (bA->m[i][j]) {
969:           PetscCall(MatCreateVecs(bA->m[i][j], NULL, &L[i]));
970:           break;
971:         }
972:       }
973:       PetscCheck(j != bA->nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Mat(Nest) contains a null row.");
974:     }

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

979:     PetscCall(PetscFree(L));
980:   }
981:   PetscFunctionReturn(PETSC_SUCCESS);
982: }

984: static PetscErrorCode MatView_Nest(Mat A, PetscViewer viewer)
985: {
986:   Mat_Nest *bA = (Mat_Nest *)A->data;
987:   PetscBool isascii, viewSub = PETSC_FALSE;

989:   PetscFunctionBegin;
990:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
991:   if (isascii) {
992:     PetscViewerFormat format;

994:     PetscCall(PetscViewerGetFormat(viewer, &format));
995:     if (format == PETSC_VIEWER_ASCII_MATLAB) {
996:       Mat T;

998:       PetscCall(MatConvert(A, MATAIJ, MAT_INITIAL_MATRIX, &T));
999:       PetscCall(MatView(T, viewer));
1000:       PetscCall(MatDestroy(&T));
1001:       PetscFunctionReturn(PETSC_SUCCESS);
1002:     }
1003:     PetscCall(PetscOptionsGetBool(((PetscObject)A)->options, ((PetscObject)A)->prefix, "-mat_view_nest_sub", &viewSub, NULL));
1004:     PetscCall(PetscViewerASCIIPushTab(viewer));
1005:     PetscCall(PetscViewerASCIIPrintf(viewer, "MatNest, rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT ", structure:\n", bA->nr, bA->nc));
1006:     for (PetscInt i = 0; i < bA->nr; i++) {
1007:       for (PetscInt j = 0; j < bA->nc; j++) {
1008:         MatType   type;
1009:         char      name[256] = "", prefix[256] = "";
1010:         PetscInt  NR, NC;
1011:         PetscBool isNest = PETSC_FALSE;

1013:         if (!bA->m[i][j]) {
1014:           PetscCall(PetscViewerASCIIPrintf(viewer, "(%" PetscInt_FMT ",%" PetscInt_FMT ") : NULL\n", i, j));
1015:           continue;
1016:         }
1017:         PetscCall(MatGetSize(bA->m[i][j], &NR, &NC));
1018:         PetscCall(MatGetType(bA->m[i][j], &type));
1019:         if (((PetscObject)bA->m[i][j])->name) PetscCall(PetscSNPrintf(name, sizeof(name), "name=\"%s\", ", ((PetscObject)bA->m[i][j])->name));
1020:         if (((PetscObject)bA->m[i][j])->prefix) PetscCall(PetscSNPrintf(prefix, sizeof(prefix), "prefix=\"%s\", ", ((PetscObject)bA->m[i][j])->prefix));
1021:         PetscCall(PetscObjectTypeCompare((PetscObject)bA->m[i][j], MATNEST, &isNest));

1023:         PetscCall(PetscViewerASCIIPrintf(viewer, "(%" PetscInt_FMT ",%" PetscInt_FMT ") : %s%stype=%s, rows=%" PetscInt_FMT ", cols=%" PetscInt_FMT "\n", i, j, name, prefix, type, NR, NC));

1025:         if (isNest || viewSub) {
1026:           PetscCall(PetscViewerASCIIPushTab(viewer)); /* push1 */
1027:           PetscCall(MatView(bA->m[i][j], viewer));
1028:           PetscCall(PetscViewerASCIIPopTab(viewer)); /* pop1 */
1029:         }
1030:       }
1031:     }
1032:     PetscCall(PetscViewerASCIIPopTab(viewer)); /* pop0 */
1033:   }
1034:   PetscFunctionReturn(PETSC_SUCCESS);
1035: }

1037: static PetscErrorCode MatZeroEntries_Nest(Mat A)
1038: {
1039:   Mat_Nest *bA = (Mat_Nest *)A->data;

1041:   PetscFunctionBegin;
1042:   for (PetscInt i = 0; i < bA->nr; i++) {
1043:     for (PetscInt j = 0; j < bA->nc; j++) {
1044:       if (!bA->m[i][j]) continue;
1045:       PetscCall(MatZeroEntries(bA->m[i][j]));
1046:     }
1047:   }
1048:   PetscFunctionReturn(PETSC_SUCCESS);
1049: }

1051: static PetscErrorCode MatCopy_Nest(Mat A, Mat B, MatStructure str)
1052: {
1053:   Mat_Nest *bA = (Mat_Nest *)A->data, *bB = (Mat_Nest *)B->data;
1054:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;
1055:   PetscBool nnzstate = PETSC_FALSE;

1057:   PetscFunctionBegin;
1058:   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);
1059:   for (i = 0; i < nr; i++) {
1060:     for (j = 0; j < nc; j++) {
1061:       PetscObjectState subnnzstate = 0;
1062:       if (bA->m[i][j] && bB->m[i][j]) {
1063:         PetscCall(MatCopy(bA->m[i][j], bB->m[i][j], str));
1064:         PetscCall(MatGetNonzeroState(bB->m[i][j], &subnnzstate));
1065:         nnzstate                 = (PetscBool)(nnzstate || bB->nnzstate[i * nc + j] != subnnzstate);
1066:         bB->nnzstate[i * nc + j] = subnnzstate;
1067:       } else if (bA->m[i][j]) { // bB->m[i][j] is NULL
1068:         Mat M;

1070:         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);
1071:         PetscCall(MatDuplicate(bA->m[i][j], MAT_COPY_VALUES, &M));
1072:         PetscCall(MatNestSetSubMat(B, i, j, M));
1073:         PetscCall(MatDestroy(&M));
1074:       } else if (bB->m[i][j]) { // bA->m[i][j] is NULL
1075:         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);
1076:         PetscCall(MatNestSetSubMat(B, i, j, NULL));
1077:       }
1078:     }
1079:   }
1080:   if (nnzstate) B->nonzerostate++;
1081:   PetscFunctionReturn(PETSC_SUCCESS);
1082: }

1084: static PetscErrorCode MatAXPY_Nest(Mat Y, PetscScalar a, Mat X, MatStructure str)
1085: {
1086:   Mat_Nest *bY = (Mat_Nest *)Y->data, *bX = (Mat_Nest *)X->data;
1087:   PetscInt  i, j, nr = bY->nr, nc = bY->nc;
1088:   PetscBool nnzstate = PETSC_FALSE;

1090:   PetscFunctionBegin;
1091:   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);
1092:   for (i = 0; i < nr; i++) {
1093:     for (j = 0; j < nc; j++) {
1094:       PetscObjectState subnnzstate = 0;
1095:       if (bY->m[i][j] && bX->m[i][j]) {
1096:         PetscCall(MatAXPY(bY->m[i][j], a, bX->m[i][j], str));
1097:       } else if (bX->m[i][j]) {
1098:         Mat M;

1100:         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);
1101:         PetscCall(MatDuplicate(bX->m[i][j], MAT_COPY_VALUES, &M));
1102:         PetscCall(MatScale(M, a));
1103:         PetscCall(MatNestSetSubMat(Y, i, j, M));
1104:         PetscCall(MatDestroy(&M));
1105:       }
1106:       if (bY->m[i][j]) PetscCall(MatGetNonzeroState(bY->m[i][j], &subnnzstate));
1107:       nnzstate                 = (PetscBool)(nnzstate || bY->nnzstate[i * nc + j] != subnnzstate);
1108:       bY->nnzstate[i * nc + j] = subnnzstate;
1109:     }
1110:   }
1111:   if (nnzstate) Y->nonzerostate++;
1112:   PetscFunctionReturn(PETSC_SUCCESS);
1113: }

1115: static PetscErrorCode MatDuplicate_Nest(Mat A, MatDuplicateOption op, Mat *B)
1116: {
1117:   Mat_Nest *bA = (Mat_Nest *)A->data;
1118:   Mat      *b;
1119:   PetscInt  i, j, nr = bA->nr, nc = bA->nc;

1121:   PetscFunctionBegin;
1122:   PetscCall(PetscMalloc1(nr * nc, &b));
1123:   for (i = 0; i < nr; i++) {
1124:     for (j = 0; j < nc; j++) {
1125:       if (bA->m[i][j]) PetscCall(MatDuplicate(bA->m[i][j], op, &b[i * nc + j]));
1126:       else b[i * nc + j] = NULL;
1127:     }
1128:   }
1129:   PetscCall(MatCreateNest(PetscObjectComm((PetscObject)A), nr, bA->isglobal.row, nc, bA->isglobal.col, b, B));
1130:   /* Give the new MatNest exclusive ownership */
1131:   for (i = 0; i < nr * nc; i++) PetscCall(MatDestroy(&b[i]));
1132:   PetscCall(PetscFree(b));

1134:   PetscCall(MatAssemblyBegin(*B, MAT_FINAL_ASSEMBLY));
1135:   PetscCall(MatAssemblyEnd(*B, MAT_FINAL_ASSEMBLY));
1136:   PetscFunctionReturn(PETSC_SUCCESS);
1137: }

1139: /* nest api */
1140: static PetscErrorCode MatNestGetSubMat_Nest(Mat A, PetscInt idxm, PetscInt jdxm, Mat *mat)
1141: {
1142:   Mat_Nest *bA = (Mat_Nest *)A->data;

1144:   PetscFunctionBegin;
1145:   PetscCheck(idxm < bA->nr, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Row too large: row %" PetscInt_FMT " max %" PetscInt_FMT, idxm, bA->nr - 1);
1146:   PetscCheck(jdxm < bA->nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Col too large: row %" PetscInt_FMT " max %" PetscInt_FMT, jdxm, bA->nc - 1);
1147:   *mat = bA->m[idxm][jdxm];
1148:   PetscFunctionReturn(PETSC_SUCCESS);
1149: }

1151: /*@
1152:   MatNestGetSubMat - Returns a single, sub-matrix from a `MATNEST`

1154:   Not Collective

1156:   Input Parameters:
1157: + A    - `MATNEST` matrix
1158: . idxm - index of the matrix within the nest matrix
1159: - jdxm - index of the matrix within the nest matrix

1161:   Output Parameter:
1162: . sub - matrix at index `idxm`, `jdxm` within the nest matrix

1164:   Level: developer

1166: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSize()`, `MatNestGetSubMats()`, `MatCreateNest()`, `MatNestSetSubMat()`,
1167:           `MatNestGetLocalISs()`, `MatNestGetISs()`
1168: @*/
1169: PetscErrorCode MatNestGetSubMat(Mat A, PetscInt idxm, PetscInt jdxm, Mat *sub)
1170: {
1171:   PetscFunctionBegin;
1175:   PetscAssertPointer(sub, 4);
1176:   PetscUseMethod(A, "MatNestGetSubMat_C", (Mat, PetscInt, PetscInt, Mat *), (A, idxm, jdxm, sub));
1177:   PetscFunctionReturn(PETSC_SUCCESS);
1178: }

1180: static PetscErrorCode MatNestSetSubMat_Nest(Mat A, PetscInt idxm, PetscInt jdxm, Mat mat)
1181: {
1182:   Mat_Nest *bA = (Mat_Nest *)A->data;
1183:   PetscInt  m, n, M, N, mi, ni, Mi, Ni;

1185:   PetscFunctionBegin;
1186:   PetscCheck(idxm < bA->nr, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Row too large: row %" PetscInt_FMT " max %" PetscInt_FMT, idxm, bA->nr - 1);
1187:   PetscCheck(jdxm < bA->nc, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Col too large: row %" PetscInt_FMT " max %" PetscInt_FMT, jdxm, bA->nc - 1);
1188:   if (mat) {
1189:     PetscCall(MatGetLocalSize(mat, &m, &n));
1190:     PetscCall(MatGetSize(mat, &M, &N));
1191:     PetscCall(ISGetLocalSize(bA->isglobal.row[idxm], &mi));
1192:     PetscCall(ISGetSize(bA->isglobal.row[idxm], &Mi));
1193:     PetscCall(ISGetLocalSize(bA->isglobal.col[jdxm], &ni));
1194:     PetscCall(ISGetSize(bA->isglobal.col[jdxm], &Ni));
1195:     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);
1196:     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);
1197:   }

1199:   /* do not increase object state */
1200:   if (mat == bA->m[idxm][jdxm]) PetscFunctionReturn(PETSC_SUCCESS);

1202:   PetscCall(PetscObjectReference((PetscObject)mat));
1203:   PetscCall(MatDestroy(&bA->m[idxm][jdxm]));
1204:   bA->m[idxm][jdxm] = mat;
1205:   PetscCall(PetscObjectStateIncrease((PetscObject)A));
1206:   if (mat) PetscCall(MatGetNonzeroState(mat, &bA->nnzstate[idxm * bA->nc + jdxm]));
1207:   else bA->nnzstate[idxm * bA->nc + jdxm] = 0;
1208:   A->nonzerostate++;
1209:   PetscFunctionReturn(PETSC_SUCCESS);
1210: }

1212: /*@
1213:   MatNestSetSubMat - Set a single submatrix in the `MATNEST`

1215:   Logically Collective

1217:   Input Parameters:
1218: + A    - `MATNEST` matrix
1219: . idxm - index of the matrix within the nest matrix
1220: . jdxm - index of the matrix within the nest matrix
1221: - sub  - matrix at index `idxm`, `jdxm` within the nest matrix

1223:   Level: developer

1225:   Notes:
1226:   The new submatrix must have the same size and communicator as that block of the nest.

1228:   This increments the reference count of the submatrix.

1230: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestSetSubMats()`, `MatNestGetSubMats()`, `MatNestGetLocalISs()`, `MatCreateNest()`,
1231:           `MatNestGetSubMat()`, `MatNestGetISs()`, `MatNestGetSize()`
1232: @*/
1233: PetscErrorCode MatNestSetSubMat(Mat A, PetscInt idxm, PetscInt jdxm, Mat sub)
1234: {
1235:   PetscFunctionBegin;
1240:   PetscTryMethod(A, "MatNestSetSubMat_C", (Mat, PetscInt, PetscInt, Mat), (A, idxm, jdxm, sub));
1241:   PetscFunctionReturn(PETSC_SUCCESS);
1242: }

1244: static PetscErrorCode MatNestGetSubMats_Nest(Mat A, PetscInt *M, PetscInt *N, Mat ***mat)
1245: {
1246:   Mat_Nest *bA = (Mat_Nest *)A->data;

1248:   PetscFunctionBegin;
1249:   if (M) *M = bA->nr;
1250:   if (N) *N = bA->nc;
1251:   if (mat) *mat = bA->m;
1252:   PetscFunctionReturn(PETSC_SUCCESS);
1253: }

1255: /*@
1256:   MatNestGetSubMats - Returns the entire two dimensional array of matrices defining a `MATNEST` matrix.

1258:   Not Collective

1260:   Input Parameter:
1261: . A - nest matrix

1263:   Output Parameters:
1264: + M   - number of submatrix rows in the nest matrix
1265: . N   - number of submatrix columns in the nest matrix
1266: - mat - array of matrices

1268:   Level: developer

1270:   Note:
1271:   The user should not free the array `mat`.

1273:   Fortran Notes:
1274:   This routine has a calling sequence `call MatNestGetSubMats(A, M, N, mat, ierr)`
1275:   where the space allocated for the optional argument `mat` is assumed large enough (if provided).
1276:   Matrices in `mat` are returned in row-major order, see `MatCreateNest()` for an example.

1278: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSize()`, `MatNestGetSubMat()`, `MatNestGetLocalISs()`, `MatCreateNest()`,
1279:           `MatNestSetSubMats()`, `MatNestGetISs()`, `MatNestSetSubMat()`
1280: @*/
1281: PetscErrorCode MatNestGetSubMats(Mat A, PetscInt *M, PetscInt *N, Mat ***mat)
1282: {
1283:   PetscFunctionBegin;
1285:   PetscUseMethod(A, "MatNestGetSubMats_C", (Mat, PetscInt *, PetscInt *, Mat ***), (A, M, N, mat));
1286:   PetscFunctionReturn(PETSC_SUCCESS);
1287: }

1289: static PetscErrorCode MatNestGetSize_Nest(Mat A, PetscInt *M, PetscInt *N)
1290: {
1291:   Mat_Nest *bA = (Mat_Nest *)A->data;

1293:   PetscFunctionBegin;
1294:   if (M) *M = bA->nr;
1295:   if (N) *N = bA->nc;
1296:   PetscFunctionReturn(PETSC_SUCCESS);
1297: }

1299: /*@
1300:   MatNestGetSize - Returns the size of the `MATNEST` matrix.

1302:   Not Collective

1304:   Input Parameter:
1305: . A - `MATNEST` matrix

1307:   Output Parameters:
1308: + M - number of rows in the nested mat
1309: - N - number of cols in the nested mat

1311:   Level: developer

1313:   Note:
1314:   `size` refers to the number of submatrices in the row and column directions of the nested matrix

1316: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSubMat()`, `MatNestGetSubMats()`, `MatCreateNest()`, `MatNestGetLocalISs()`,
1317:           `MatNestGetISs()`
1318: @*/
1319: PetscErrorCode MatNestGetSize(Mat A, PetscInt *M, PetscInt *N)
1320: {
1321:   PetscFunctionBegin;
1323:   PetscUseMethod(A, "MatNestGetSize_C", (Mat, PetscInt *, PetscInt *), (A, M, N));
1324:   PetscFunctionReturn(PETSC_SUCCESS);
1325: }

1327: static PetscErrorCode MatNestGetISs_Nest(Mat A, IS rows[], IS cols[])
1328: {
1329:   Mat_Nest *vs = (Mat_Nest *)A->data;

1331:   PetscFunctionBegin;
1332:   if (rows) {
1333:     for (PetscInt i = 0; i < vs->nr; i++) rows[i] = vs->isglobal.row[i];
1334:   }
1335:   if (cols) {
1336:     for (PetscInt i = 0; i < vs->nc; i++) cols[i] = vs->isglobal.col[i];
1337:   }
1338:   PetscFunctionReturn(PETSC_SUCCESS);
1339: }

1341: /*@
1342:   MatNestGetISs - Returns the index sets partitioning the row and column spaces of a `MATNEST`

1344:   Not Collective

1346:   Input Parameter:
1347: . A - `MATNEST` matrix

1349:   Output Parameters:
1350: + rows - array of row index sets (pass `NULL` to ignore)
1351: - cols - array of column index sets (pass `NULL` to ignore)

1353:   Level: advanced

1355:   Note:
1356:   The user must have allocated arrays of the correct size. The reference count is not increased on the returned `IS`s.

1358: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSubMat()`, `MatNestGetSubMats()`, `MatNestGetSize()`, `MatNestGetLocalISs()`,
1359:           `MatCreateNest()`, `MatNestSetSubMats()`
1360: @*/
1361: PetscErrorCode MatNestGetISs(Mat A, IS rows[], IS cols[])
1362: {
1363:   PetscFunctionBegin;
1365:   PetscUseMethod(A, "MatNestGetISs_C", (Mat, IS[], IS[]), (A, rows, cols));
1366:   PetscFunctionReturn(PETSC_SUCCESS);
1367: }

1369: static PetscErrorCode MatNestGetLocalISs_Nest(Mat A, IS rows[], IS cols[])
1370: {
1371:   Mat_Nest *vs = (Mat_Nest *)A->data;

1373:   PetscFunctionBegin;
1374:   if (rows) {
1375:     for (PetscInt i = 0; i < vs->nr; i++) rows[i] = vs->islocal.row[i];
1376:   }
1377:   if (cols) {
1378:     for (PetscInt i = 0; i < vs->nc; i++) cols[i] = vs->islocal.col[i];
1379:   }
1380:   PetscFunctionReturn(PETSC_SUCCESS);
1381: }

1383: /*@
1384:   MatNestGetLocalISs - Returns the index sets partitioning the row and column spaces of a `MATNEST`

1386:   Not Collective

1388:   Input Parameter:
1389: . A - `MATNEST` matrix

1391:   Output Parameters:
1392: + rows - array of row index sets (pass `NULL` to ignore)
1393: - cols - array of column index sets (pass `NULL` to ignore)

1395:   Level: advanced

1397:   Note:
1398:   The user must have allocated arrays of the correct size. The reference count is not increased on the returned `IS`s.

1400: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatNestGetSubMat()`, `MatNestGetSubMats()`, `MatNestGetSize()`, `MatNestGetISs()`, `MatCreateNest()`,
1401:           `MatNestSetSubMats()`, `MatNestSetSubMat()`
1402: @*/
1403: PetscErrorCode MatNestGetLocalISs(Mat A, IS rows[], IS cols[])
1404: {
1405:   PetscFunctionBegin;
1407:   PetscUseMethod(A, "MatNestGetLocalISs_C", (Mat, IS[], IS[]), (A, rows, cols));
1408:   PetscFunctionReturn(PETSC_SUCCESS);
1409: }

1411: static PetscErrorCode MatNestSetVecType_Nest(Mat A, VecType vtype)
1412: {
1413:   PetscBool flg;

1415:   PetscFunctionBegin;
1416:   PetscCall(PetscStrcmp(vtype, VECNEST, &flg));
1417:   /* In reality, this only distinguishes VECNEST and "other" */
1418:   if (flg) A->ops->getvecs = MatCreateVecs_Nest;
1419:   else A->ops->getvecs = NULL;
1420:   PetscFunctionReturn(PETSC_SUCCESS);
1421: }

1423: /*@
1424:   MatNestSetVecType - Sets the type of `Vec` returned by `MatCreateVecs()`

1426:   Not Collective

1428:   Input Parameters:
1429: + A     - `MATNEST` matrix
1430: - vtype - `VecType` to use for creating vectors

1432:   Level: developer

1434: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreateVecs()`, `MatCreateNest()`, `VecType`
1435: @*/
1436: PetscErrorCode MatNestSetVecType(Mat A, VecType vtype)
1437: {
1438:   PetscFunctionBegin;
1440:   PetscTryMethod(A, "MatNestSetVecType_C", (Mat, VecType), (A, vtype));
1441:   PetscFunctionReturn(PETSC_SUCCESS);
1442: }

1444: static PetscErrorCode MatNestSetSubMats_Nest(Mat A, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[], const Mat a[])
1445: {
1446:   Mat_Nest *s = (Mat_Nest *)A->data;
1447:   PetscInt  i, j, m, n, M, N;
1448:   PetscBool cong, isstd, sametype = PETSC_FALSE;
1449:   VecType   vtype, type;

1451:   PetscFunctionBegin;
1452:   PetscCall(MatReset_Nest(A));

1454:   s->nr = nr;
1455:   s->nc = nc;

1457:   /* Create space for submatrices */
1458:   PetscCall(PetscMalloc1(nr, &s->m));
1459:   PetscCall(PetscMalloc1(nr * nc, &s->m[0]));
1460:   for (i = 0; i < nr; i++) {
1461:     s->m[i] = s->m[0] + i * nc;
1462:     for (j = 0; j < nc; j++) {
1463:       s->m[i][j] = a ? a[i * nc + j] : NULL;
1464:       PetscCall(PetscObjectReference((PetscObject)s->m[i][j]));
1465:     }
1466:   }
1467:   PetscCall(MatGetVecType(A, &vtype));
1468:   PetscCall(PetscStrcmp(vtype, VECSTANDARD, &isstd));
1469:   if (isstd) {
1470:     /* check if all blocks have the same vectype */
1471:     vtype = NULL;
1472:     for (i = 0; i < nr; i++) {
1473:       for (j = 0; j < nc; j++) {
1474:         if (s->m[i][j]) {
1475:           if (!vtype) { /* first visited block */
1476:             PetscCall(MatGetVecType(s->m[i][j], &vtype));
1477:             sametype = PETSC_TRUE;
1478:           } else if (sametype) {
1479:             PetscCall(MatGetVecType(s->m[i][j], &type));
1480:             PetscCall(PetscStrcmp(vtype, type, &sametype));
1481:           }
1482:         }
1483:       }
1484:     }
1485:     if (sametype) { /* propagate vectype */
1486:       PetscCall(MatSetVecType(A, vtype));
1487:     }
1488:   }

1490:   PetscCall(MatSetUp_NestIS_Private(A, nr, is_row, nc, is_col));

1492:   PetscCall(PetscMalloc1(nr, &s->row_len));
1493:   PetscCall(PetscMalloc1(nc, &s->col_len));
1494:   for (i = 0; i < nr; i++) s->row_len[i] = -1;
1495:   for (j = 0; j < nc; j++) s->col_len[j] = -1;

1497:   PetscCall(PetscCalloc1(nr * nc, &s->nnzstate));
1498:   for (i = 0; i < nr; i++) {
1499:     for (j = 0; j < nc; j++) {
1500:       if (s->m[i][j]) PetscCall(MatGetNonzeroState(s->m[i][j], &s->nnzstate[i * nc + j]));
1501:     }
1502:   }

1504:   PetscCall(MatNestGetSizes_Private(A, &m, &n, &M, &N));

1506:   PetscCall(PetscLayoutSetSize(A->rmap, M));
1507:   PetscCall(PetscLayoutSetLocalSize(A->rmap, m));
1508:   PetscCall(PetscLayoutSetSize(A->cmap, N));
1509:   PetscCall(PetscLayoutSetLocalSize(A->cmap, n));

1511:   PetscCall(PetscLayoutSetUp(A->rmap));
1512:   PetscCall(PetscLayoutSetUp(A->cmap));

1514:   /* disable operations that are not supported for non-square matrices,
1515:      or matrices for which is_row != is_col  */
1516:   PetscCall(MatHasCongruentLayouts(A, &cong));
1517:   if (cong && nr != nc) cong = PETSC_FALSE;
1518:   if (cong) {
1519:     for (i = 0; cong && i < nr; i++) PetscCall(ISEqualUnsorted(s->isglobal.row[i], s->isglobal.col[i], &cong));
1520:   }
1521:   if (!cong) {
1522:     A->ops->getdiagonal = NULL;
1523:     A->ops->shift       = NULL;
1524:     A->ops->diagonalset = NULL;
1525:   }

1527:   PetscCall(PetscCalloc2(nr, &s->left, nc, &s->right));
1528:   PetscCall(PetscObjectStateIncrease((PetscObject)A));
1529:   A->nonzerostate++;
1530:   PetscFunctionReturn(PETSC_SUCCESS);
1531: }

1533: /*@
1534:   MatNestSetSubMats - Sets the nested submatrices in a `MATNEST`

1536:   Collective

1538:   Input Parameters:
1539: + A      - `MATNEST` matrix
1540: . nr     - number of nested row blocks
1541: . is_row - index sets for each nested row block, or `NULL` to make contiguous
1542: . nc     - number of nested column blocks
1543: . is_col - index sets for each nested column block, or `NULL` to make contiguous
1544: - a      - array of $ nr \times nc$ submatrices, or `NULL`

1546:   Level: advanced

1548:   Notes:
1549:   This always resets any block matrix information previously set.

1551:   Pass `NULL` in the corresponding entry of `a` for an empty block.

1553:   In both C and Fortran, `a` must be a one-dimensional array representing a two-dimensional row-major order array containing the matrices. See
1554:   `MatCreateNest()` for an example.

1556:   Fortran Note:
1557:   Pass `PETSC_NULL_MAT` in the corresponding entry of `a` for an empty block

1559: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreateNest()`, `MatNestSetSubMat()`, `MatNestGetSubMat()`, `MatNestGetSubMats()`
1560: @*/
1561: PetscErrorCode MatNestSetSubMats(Mat A, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[], const Mat a[]) PeNSS
1562: {
1563:   PetscFunctionBegin;
1566:   PetscCheck(nr >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Number of rows cannot be negative");
1567:   if (nr && is_row) {
1568:     PetscAssertPointer(is_row, 3);
1570:   }
1572:   PetscCheck(nc >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_OUTOFRANGE, "Number of columns cannot be negative");
1573:   if (nc && is_col) {
1574:     PetscAssertPointer(is_col, 5);
1576:   }
1577:   PetscTryMethod(A, "MatNestSetSubMats_C", (Mat, PetscInt, const IS[], PetscInt, const IS[], const Mat[]), (A, nr, is_row, nc, is_col, a));
1578:   PetscFunctionReturn(PETSC_SUCCESS);
1579: }

1581: static PetscErrorCode MatNestCreateAggregateL2G_Private(Mat A, PetscInt n, const IS islocal[], const IS isglobal[], PetscBool colflg, ISLocalToGlobalMapping *ltog)
1582: {
1583:   PetscBool flg;
1584:   PetscInt  i, j, m, mi, *ix;

1586:   PetscFunctionBegin;
1587:   *ltog = NULL;
1588:   for (i = 0, m = 0, flg = PETSC_FALSE; i < n; i++) {
1589:     if (islocal[i]) {
1590:       PetscCall(ISGetLocalSize(islocal[i], &mi));
1591:       flg = PETSC_TRUE; /* We found a non-trivial entry */
1592:     } else {
1593:       PetscCall(ISGetLocalSize(isglobal[i], &mi));
1594:     }
1595:     m += mi;
1596:   }
1597:   if (!flg) PetscFunctionReturn(PETSC_SUCCESS);

1599:   PetscCall(PetscMalloc1(m, &ix));
1600:   for (i = 0, m = 0; i < n; i++) {
1601:     ISLocalToGlobalMapping smap = NULL;
1602:     Mat                    sub  = NULL;
1603:     PetscSF                sf;
1604:     PetscLayout            map;
1605:     const PetscInt        *ix2;

1607:     if (!colflg) {
1608:       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1609:     } else {
1610:       PetscCall(MatNestFindNonzeroSubMatCol(A, i, &sub));
1611:     }
1612:     if (sub) {
1613:       if (!colflg) PetscCall(MatGetLocalToGlobalMapping(sub, &smap, NULL));
1614:       else PetscCall(MatGetLocalToGlobalMapping(sub, NULL, &smap));
1615:     }
1616:     /*
1617:        Now we need to extract the monolithic global indices that correspond to the given split global indices.
1618:        In many/most cases, we only want MatGetLocalSubMatrix() to work, in which case we only need to know the size of the local spaces.
1619:     */
1620:     PetscCall(ISGetIndices(isglobal[i], &ix2));
1621:     if (islocal[i]) {
1622:       PetscInt *ilocal, *iremote;
1623:       PetscInt  mil, nleaves;

1625:       PetscCall(ISGetLocalSize(islocal[i], &mi));
1626:       PetscCheck(smap, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Missing local to global map");
1627:       for (j = 0; j < mi; j++) ix[m + j] = j;
1628:       PetscCall(ISLocalToGlobalMappingApply(smap, mi, ix + m, ix + m));

1630:       /* PetscSFSetGraphLayout does not like negative indices */
1631:       PetscCall(PetscMalloc2(mi, &ilocal, mi, &iremote));
1632:       for (j = 0, nleaves = 0; j < mi; j++) {
1633:         if (ix[m + j] < 0) continue;
1634:         ilocal[nleaves]  = j;
1635:         iremote[nleaves] = ix[m + j];
1636:         nleaves++;
1637:       }
1638:       PetscCall(ISGetLocalSize(isglobal[i], &mil));
1639:       PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)A), &sf));
1640:       PetscCall(PetscLayoutCreate(PetscObjectComm((PetscObject)A), &map));
1641:       PetscCall(PetscLayoutSetLocalSize(map, mil));
1642:       PetscCall(PetscLayoutSetUp(map));
1643:       PetscCall(PetscSFSetGraphLayout(sf, map, nleaves, ilocal, PETSC_USE_POINTER, iremote));
1644:       PetscCall(PetscLayoutDestroy(&map));
1645:       PetscCall(PetscSFBcastBegin(sf, MPIU_INT, ix2, ix + m, MPI_REPLACE));
1646:       PetscCall(PetscSFBcastEnd(sf, MPIU_INT, ix2, ix + m, MPI_REPLACE));
1647:       PetscCall(PetscSFDestroy(&sf));
1648:       PetscCall(PetscFree2(ilocal, iremote));
1649:     } else {
1650:       PetscCall(ISGetLocalSize(isglobal[i], &mi));
1651:       for (j = 0; j < mi; j++) ix[m + j] = ix2[j];
1652:     }
1653:     PetscCall(ISRestoreIndices(isglobal[i], &ix2));
1654:     m += mi;
1655:   }
1656:   PetscCall(ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)A), 1, m, ix, PETSC_OWN_POINTER, ltog));
1657:   PetscFunctionReturn(PETSC_SUCCESS);
1658: }

1660: /* If an IS was provided, there is nothing Nest needs to do, otherwise Nest will build a strided IS */
1661: /*
1662:   nprocessors = NP
1663:   Nest x^T = ((g_0,g_1,...g_nprocs-1), (h_0,h_1,...h_NP-1))
1664:        proc 0: => (g_0,h_0,)
1665:        proc 1: => (g_1,h_1,)
1666:        ...
1667:        proc nprocs-1: => (g_NP-1,h_NP-1,)

1669:             proc 0:                      proc 1:                    proc nprocs-1:
1670:     is[0] = (0,1,2,...,nlocal(g_0)-1)  (0,1,...,nlocal(g_1)-1)  (0,1,...,nlocal(g_NP-1))

1672:             proc 0:
1673:     is[1] = (nlocal(g_0),nlocal(g_0)+1,...,nlocal(g_0)+nlocal(h_0)-1)
1674:             proc 1:
1675:     is[1] = (nlocal(g_1),nlocal(g_1)+1,...,nlocal(g_1)+nlocal(h_1)-1)

1677:             proc NP-1:
1678:     is[1] = (nlocal(g_NP-1),nlocal(g_NP-1)+1,...,nlocal(g_NP-1)+nlocal(h_NP-1)-1)
1679: */
1680: static PetscErrorCode MatSetUp_NestIS_Private(Mat A, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[])
1681: {
1682:   Mat_Nest *vs = (Mat_Nest *)A->data;
1683:   PetscInt  i, j, offset, n, nsum, bs;
1684:   Mat       sub = NULL;

1686:   PetscFunctionBegin;
1687:   PetscCall(PetscMalloc1(nr, &vs->isglobal.row));
1688:   PetscCall(PetscMalloc1(nc, &vs->isglobal.col));
1689:   if (is_row) { /* valid IS is passed in */
1690:     /* refs on is[] are incremented */
1691:     for (i = 0; i < vs->nr; i++) {
1692:       PetscCall(PetscObjectReference((PetscObject)is_row[i]));
1693:       vs->isglobal.row[i] = is_row[i];
1694:     }
1695:   } else { /* Create the ISs by inspecting sizes of a submatrix in each row */
1696:     nsum = 0;
1697:     for (i = 0; i < vs->nr; i++) { /* Add up the local sizes to compute the aggregate offset */
1698:       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1699:       PetscCheck(sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "No nonzero submatrix in row %" PetscInt_FMT, i);
1700:       PetscCall(MatGetLocalSize(sub, &n, NULL));
1701:       PetscCheck(n >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Sizes have not yet been set for submatrix");
1702:       nsum += n;
1703:     }
1704:     PetscCallMPI(MPI_Scan(&nsum, &offset, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)A)));
1705:     offset -= nsum;
1706:     for (i = 0; i < vs->nr; i++) {
1707:       PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1708:       PetscCall(MatGetLocalSize(sub, &n, NULL));
1709:       PetscCall(MatGetBlockSizes(sub, &bs, NULL));
1710:       PetscCall(ISCreateStride(PetscObjectComm((PetscObject)sub), n, offset, 1, &vs->isglobal.row[i]));
1711:       PetscCall(ISSetBlockSize(vs->isglobal.row[i], bs));
1712:       offset += n;
1713:     }
1714:   }

1716:   if (is_col) { /* valid IS is passed in */
1717:     /* refs on is[] are incremented */
1718:     for (j = 0; j < vs->nc; j++) {
1719:       PetscCall(PetscObjectReference((PetscObject)is_col[j]));
1720:       vs->isglobal.col[j] = is_col[j];
1721:     }
1722:   } else { /* Create the ISs by inspecting sizes of a submatrix in each column */
1723:     offset = A->cmap->rstart;
1724:     nsum   = 0;
1725:     for (j = 0; j < vs->nc; j++) {
1726:       PetscCall(MatNestFindNonzeroSubMatCol(A, j, &sub));
1727:       PetscCheck(sub, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "No nonzero submatrix in column %" PetscInt_FMT, i);
1728:       PetscCall(MatGetLocalSize(sub, NULL, &n));
1729:       PetscCheck(n >= 0, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Sizes have not yet been set for submatrix");
1730:       nsum += n;
1731:     }
1732:     PetscCallMPI(MPI_Scan(&nsum, &offset, 1, MPIU_INT, MPI_SUM, PetscObjectComm((PetscObject)A)));
1733:     offset -= nsum;
1734:     for (j = 0; j < vs->nc; j++) {
1735:       PetscCall(MatNestFindNonzeroSubMatCol(A, j, &sub));
1736:       PetscCall(MatGetLocalSize(sub, NULL, &n));
1737:       PetscCall(MatGetBlockSizes(sub, NULL, &bs));
1738:       PetscCall(ISCreateStride(PetscObjectComm((PetscObject)sub), n, offset, 1, &vs->isglobal.col[j]));
1739:       PetscCall(ISSetBlockSize(vs->isglobal.col[j], bs));
1740:       offset += n;
1741:     }
1742:   }

1744:   /* Set up the local ISs */
1745:   PetscCall(PetscMalloc1(vs->nr, &vs->islocal.row));
1746:   PetscCall(PetscMalloc1(vs->nc, &vs->islocal.col));
1747:   for (i = 0, offset = 0; i < vs->nr; i++) {
1748:     IS                     isloc;
1749:     ISLocalToGlobalMapping rmap = NULL;
1750:     PetscInt               nlocal, bs;
1751:     PetscCall(MatNestFindNonzeroSubMatRow(A, i, &sub));
1752:     if (sub) PetscCall(MatGetLocalToGlobalMapping(sub, &rmap, NULL));
1753:     if (rmap) {
1754:       PetscCall(MatGetBlockSizes(sub, &bs, NULL));
1755:       PetscCall(ISLocalToGlobalMappingGetSize(rmap, &nlocal));
1756:       PetscCall(ISCreateStride(PETSC_COMM_SELF, nlocal, offset, 1, &isloc));
1757:       PetscCall(ISSetBlockSize(isloc, bs));
1758:     } else {
1759:       nlocal = 0;
1760:       isloc  = NULL;
1761:     }
1762:     vs->islocal.row[i] = isloc;
1763:     offset += nlocal;
1764:   }
1765:   for (i = 0, offset = 0; i < vs->nc; i++) {
1766:     IS                     isloc;
1767:     ISLocalToGlobalMapping cmap = NULL;
1768:     PetscInt               nlocal, bs;
1769:     PetscCall(MatNestFindNonzeroSubMatCol(A, i, &sub));
1770:     if (sub) PetscCall(MatGetLocalToGlobalMapping(sub, NULL, &cmap));
1771:     if (cmap) {
1772:       PetscCall(MatGetBlockSizes(sub, NULL, &bs));
1773:       PetscCall(ISLocalToGlobalMappingGetSize(cmap, &nlocal));
1774:       PetscCall(ISCreateStride(PETSC_COMM_SELF, nlocal, offset, 1, &isloc));
1775:       PetscCall(ISSetBlockSize(isloc, bs));
1776:     } else {
1777:       nlocal = 0;
1778:       isloc  = NULL;
1779:     }
1780:     vs->islocal.col[i] = isloc;
1781:     offset += nlocal;
1782:   }

1784:   /* Set up the aggregate ISLocalToGlobalMapping */
1785:   {
1786:     ISLocalToGlobalMapping rmap, cmap;
1787:     PetscCall(MatNestCreateAggregateL2G_Private(A, vs->nr, vs->islocal.row, vs->isglobal.row, PETSC_FALSE, &rmap));
1788:     PetscCall(MatNestCreateAggregateL2G_Private(A, vs->nc, vs->islocal.col, vs->isglobal.col, PETSC_TRUE, &cmap));
1789:     if (rmap && cmap) PetscCall(MatSetLocalToGlobalMapping(A, rmap, cmap));
1790:     PetscCall(ISLocalToGlobalMappingDestroy(&rmap));
1791:     PetscCall(ISLocalToGlobalMappingDestroy(&cmap));
1792:   }

1794:   if (PetscDefined(USE_DEBUG)) {
1795:     for (i = 0; i < vs->nr; i++) {
1796:       for (j = 0; j < vs->nc; j++) {
1797:         PetscInt m, n, M, N, mi, ni, Mi, Ni;
1798:         Mat      B = vs->m[i][j];
1799:         if (!B) continue;
1800:         PetscCall(MatGetSize(B, &M, &N));
1801:         PetscCall(MatGetLocalSize(B, &m, &n));
1802:         PetscCall(ISGetSize(vs->isglobal.row[i], &Mi));
1803:         PetscCall(ISGetSize(vs->isglobal.col[j], &Ni));
1804:         PetscCall(ISGetLocalSize(vs->isglobal.row[i], &mi));
1805:         PetscCall(ISGetLocalSize(vs->isglobal.col[j], &ni));
1806:         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);
1807:         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);
1808:       }
1809:     }
1810:   }

1812:   /* Set A->assembled if all non-null blocks are currently assembled */
1813:   for (i = 0; i < vs->nr; i++) {
1814:     for (j = 0; j < vs->nc; j++) {
1815:       if (vs->m[i][j] && !vs->m[i][j]->assembled) PetscFunctionReturn(PETSC_SUCCESS);
1816:     }
1817:   }
1818:   A->assembled = PETSC_TRUE;
1819:   PetscFunctionReturn(PETSC_SUCCESS);
1820: }

1822: /*@
1823:   MatCreateNest - Creates a new `MATNEST` matrix containing several nested submatrices, each stored separately

1825:   Collective

1827:   Input Parameters:
1828: + comm   - Communicator for the new `MATNEST`
1829: . nr     - number of nested row blocks
1830: . is_row - index sets for each nested row block, or `NULL` to make contiguous
1831: . nc     - number of nested column blocks
1832: . is_col - index sets for each nested column block, or `NULL` to make contiguous
1833: - a      - array of $nr \times nc$ submatrices, empty submatrices can be passed using `NULL`

1835:   Output Parameter:
1836: . B - new matrix

1838:   Level: advanced

1840:   Note:
1841:   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.
1842:   For instance, to represent the matrix
1843:   $\begin{bmatrix} A_{11} & A_{12} \\ A_{21} & A_{22}\end{bmatrix}$
1844:   one should use `Mat a[4]={A11,A12,A21,A22}`.

1846:   Fortran Note:
1847:   Pass `PETSC_NULL_MAT` in the corresponding entry of `a` for an empty block

1849: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreate()`, `VecCreateNest()`, `DMCreateMatrix()`, `MatNestSetSubMat()`,
1850:           `MatNestGetSubMat()`, `MatNestGetLocalISs()`, `MatNestGetSize()`,
1851:           `MatNestGetISs()`, `MatNestSetSubMats()`, `MatNestGetSubMats()`
1852: @*/
1853: PetscErrorCode MatCreateNest(MPI_Comm comm, PetscInt nr, const IS is_row[], PetscInt nc, const IS is_col[], const Mat a[], Mat *B) PeNSS
1854: {
1855:   PetscFunctionBegin;
1856:   PetscCall(MatCreate(comm, B));
1857:   PetscCall(MatSetType(*B, MATNEST));
1858:   (*B)->preallocated = PETSC_TRUE;
1859:   PetscCall(MatNestSetSubMats(*B, nr, is_row, nc, is_col, a));
1860:   PetscFunctionReturn(PETSC_SUCCESS);
1861: }

1863: static PetscErrorCode MatConvert_Nest_SeqAIJ_fast(Mat A, MatType newtype, MatReuse reuse, Mat *newmat)
1864: {
1865:   Mat_Nest     *nest = (Mat_Nest *)A->data;
1866:   Mat          *trans;
1867:   PetscScalar **avv;
1868:   PetscScalar  *vv;
1869:   PetscInt    **aii, **ajj;
1870:   PetscInt     *ii, *jj, *ci;
1871:   PetscInt      nr, nc, nnz, i, j;
1872:   PetscBool     done;

1874:   PetscFunctionBegin;
1875:   PetscCall(MatGetSize(A, &nr, &nc));
1876:   if (reuse == MAT_REUSE_MATRIX) {
1877:     PetscInt rnr;

1879:     PetscCall(MatGetRowIJ(*newmat, 0, PETSC_FALSE, PETSC_FALSE, &rnr, (const PetscInt **)&ii, (const PetscInt **)&jj, &done));
1880:     PetscCheck(done, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "MatGetRowIJ");
1881:     PetscCheck(rnr == nr, PetscObjectComm((PetscObject)A), PETSC_ERR_USER, "Cannot reuse matrix, wrong number of rows");
1882:     PetscCall(MatSeqAIJGetArray(*newmat, &vv));
1883:   }
1884:   /* extract CSR for nested SeqAIJ matrices */
1885:   nnz = 0;
1886:   PetscCall(PetscCalloc4(nest->nr * nest->nc, &aii, nest->nr * nest->nc, &ajj, nest->nr * nest->nc, &avv, nest->nr * nest->nc, &trans));
1887:   for (i = 0; i < nest->nr; ++i) {
1888:     for (j = 0; j < nest->nc; ++j) {
1889:       Mat B = nest->m[i][j];
1890:       if (B) {
1891:         PetscScalar *naa;
1892:         PetscInt    *nii, *njj, nnr;
1893:         PetscBool    istrans;

1895:         PetscCall(PetscObjectTypeCompare((PetscObject)B, MATTRANSPOSEVIRTUAL, &istrans));
1896:         if (istrans) {
1897:           Mat Bt;

1899:           PetscCall(MatTransposeGetMat(B, &Bt));
1900:           PetscCall(MatTranspose(Bt, MAT_INITIAL_MATRIX, &trans[i * nest->nc + j]));
1901:           B = trans[i * nest->nc + j];
1902:         } else {
1903:           PetscCall(PetscObjectTypeCompare((PetscObject)B, MATHERMITIANTRANSPOSEVIRTUAL, &istrans));
1904:           if (istrans) {
1905:             Mat Bt;

1907:             PetscCall(MatHermitianTransposeGetMat(B, &Bt));
1908:             PetscCall(MatHermitianTranspose(Bt, MAT_INITIAL_MATRIX, &trans[i * nest->nc + j]));
1909:             B = trans[i * nest->nc + j];
1910:           }
1911:         }
1912:         PetscCall(MatGetRowIJ(B, 0, PETSC_FALSE, PETSC_FALSE, &nnr, (const PetscInt **)&nii, (const PetscInt **)&njj, &done));
1913:         PetscCheck(done, PetscObjectComm((PetscObject)B), PETSC_ERR_PLIB, "MatGetRowIJ");
1914:         PetscCall(MatSeqAIJGetArray(B, &naa));
1915:         nnz += nii[nnr];

1917:         aii[i * nest->nc + j] = nii;
1918:         ajj[i * nest->nc + j] = njj;
1919:         avv[i * nest->nc + j] = naa;
1920:       }
1921:     }
1922:   }
1923:   if (reuse != MAT_REUSE_MATRIX) {
1924:     PetscCall(PetscMalloc1(nr + 1, &ii));
1925:     PetscCall(PetscMalloc1(nnz, &jj));
1926:     PetscCall(PetscMalloc1(nnz, &vv));
1927:   } else {
1928:     PetscCheck(nnz == ii[nr], PetscObjectComm((PetscObject)A), PETSC_ERR_USER, "Cannot reuse matrix, wrong number of nonzeros");
1929:   }

1931:   /* new row pointer */
1932:   PetscCall(PetscArrayzero(ii, nr + 1));
1933:   for (i = 0; i < nest->nr; ++i) {
1934:     PetscInt ncr, rst;

1936:     PetscCall(ISStrideGetInfo(nest->isglobal.row[i], &rst, NULL));
1937:     PetscCall(ISGetLocalSize(nest->isglobal.row[i], &ncr));
1938:     for (j = 0; j < nest->nc; ++j) {
1939:       if (aii[i * nest->nc + j]) {
1940:         PetscInt *nii = aii[i * nest->nc + j];

1942:         for (PetscInt ir = rst; ir < ncr + rst; ++ir) {
1943:           ii[ir + 1] += nii[1] - nii[0];
1944:           nii++;
1945:         }
1946:       }
1947:     }
1948:   }
1949:   for (i = 0; i < nr; i++) ii[i + 1] += ii[i];

1951:   /* construct CSR for the new matrix */
1952:   PetscCall(PetscCalloc1(nr, &ci));
1953:   for (i = 0; i < nest->nr; ++i) {
1954:     PetscInt ncr, rst;

1956:     PetscCall(ISStrideGetInfo(nest->isglobal.row[i], &rst, NULL));
1957:     PetscCall(ISGetLocalSize(nest->isglobal.row[i], &ncr));
1958:     for (j = 0; j < nest->nc; ++j) {
1959:       if (aii[i * nest->nc + j]) {
1960:         PetscScalar *nvv = avv[i * nest->nc + j], vscale = 1.0, vshift = 0.0;
1961:         PetscInt    *nii = aii[i * nest->nc + j];
1962:         PetscInt    *njj = ajj[i * nest->nc + j];
1963:         PetscInt     cst;

1965:         if (trans[i * nest->nc + j]) {
1966:           vscale = ((Mat_Shell *)nest->m[i][j]->data)->vscale;
1967:           vshift = ((Mat_Shell *)nest->m[i][j]->data)->vshift;
1968:         }
1969:         PetscCall(ISStrideGetInfo(nest->isglobal.col[j], &cst, NULL));
1970:         for (PetscInt ir = rst; ir < ncr + rst; ++ir) {
1971:           PetscInt ij, rsize = nii[1] - nii[0], ist = ii[ir] + ci[ir];

1973:           for (ij = 0; ij < rsize; ij++) {
1974:             jj[ist + ij] = *njj + cst;
1975:             vv[ist + ij] = vscale * *nvv;
1976:             if (PetscUnlikely(vshift != 0.0 && *njj == ir - rst)) vv[ist + ij] += vshift;
1977:             njj++;
1978:             nvv++;
1979:           }
1980:           ci[ir] += rsize;
1981:           nii++;
1982:         }
1983:       }
1984:     }
1985:   }
1986:   PetscCall(PetscFree(ci));

1988:   /* restore info */
1989:   for (i = 0; i < nest->nr; ++i) {
1990:     for (j = 0; j < nest->nc; ++j) {
1991:       Mat B = nest->m[i][j];
1992:       if (B) {
1993:         PetscInt nnr = 0, k = i * nest->nc + j;

1995:         B = (trans[k] ? trans[k] : B);
1996:         PetscCall(MatRestoreRowIJ(B, 0, PETSC_FALSE, PETSC_FALSE, &nnr, (const PetscInt **)&aii[k], (const PetscInt **)&ajj[k], &done));
1997:         PetscCheck(done, PetscObjectComm((PetscObject)B), PETSC_ERR_PLIB, "MatRestoreRowIJ");
1998:         PetscCall(MatSeqAIJRestoreArray(B, &avv[k]));
1999:         PetscCall(MatDestroy(&trans[k]));
2000:       }
2001:     }
2002:   }
2003:   PetscCall(PetscFree4(aii, ajj, avv, trans));

2005:   /* finalize newmat */
2006:   if (reuse == MAT_INITIAL_MATRIX) {
2007:     PetscCall(MatCreateSeqAIJWithArrays(PetscObjectComm((PetscObject)A), nr, nc, ii, jj, vv, newmat));
2008:   } else if (reuse == MAT_INPLACE_MATRIX) {
2009:     Mat B;

2011:     PetscCall(MatCreateSeqAIJWithArrays(PetscObjectComm((PetscObject)A), nr, nc, ii, jj, vv, &B));
2012:     PetscCall(MatHeaderReplace(A, &B));
2013:   }
2014:   PetscCall(MatAssemblyBegin(*newmat, MAT_FINAL_ASSEMBLY));
2015:   PetscCall(MatAssemblyEnd(*newmat, MAT_FINAL_ASSEMBLY));
2016:   {
2017:     Mat_SeqAIJ *a = (Mat_SeqAIJ *)((*newmat)->data);
2018:     a->free_a     = PETSC_TRUE;
2019:     a->free_ij    = PETSC_TRUE;
2020:   }
2021:   PetscFunctionReturn(PETSC_SUCCESS);
2022: }

2024: PETSC_INTERN PetscErrorCode MatAXPY_Dense_Nest(Mat Y, PetscScalar a, Mat X)
2025: {
2026:   Mat_Nest *nest = (Mat_Nest *)X->data;
2027:   PetscInt  i, j, k, rstart;
2028:   PetscBool flg;

2030:   PetscFunctionBegin;
2031:   /* Fill by row */
2032:   for (j = 0; j < nest->nc; ++j) {
2033:     /* Using global column indices and ISAllGather() is not scalable. */
2034:     IS              bNis;
2035:     PetscInt        bN;
2036:     const PetscInt *bNindices;
2037:     PetscCall(ISAllGather(nest->isglobal.col[j], &bNis));
2038:     PetscCall(ISGetSize(bNis, &bN));
2039:     PetscCall(ISGetIndices(bNis, &bNindices));
2040:     for (i = 0; i < nest->nr; ++i) {
2041:       Mat             B = nest->m[i][j], D = NULL;
2042:       PetscInt        bm, br;
2043:       const PetscInt *bmindices;
2044:       if (!B) continue;
2045:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATTRANSPOSEVIRTUAL, MATHERMITIANTRANSPOSEVIRTUAL, ""));
2046:       if (flg) {
2047:         PetscTryMethod(B, "MatTransposeGetMat_C", (Mat, Mat *), (B, &D));
2048:         PetscTryMethod(B, "MatHermitianTransposeGetMat_C", (Mat, Mat *), (B, &D));
2049:         PetscCall(MatConvert(B, ((PetscObject)D)->type_name, MAT_INITIAL_MATRIX, &D));
2050:         B = D;
2051:       }
2052:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATSEQSBAIJ, MATMPISBAIJ, ""));
2053:       if (flg) {
2054:         if (D) PetscCall(MatConvert(D, MATBAIJ, MAT_INPLACE_MATRIX, &D));
2055:         else PetscCall(MatConvert(B, MATBAIJ, MAT_INITIAL_MATRIX, &D));
2056:         B = D;
2057:       }
2058:       PetscCall(ISGetLocalSize(nest->isglobal.row[i], &bm));
2059:       PetscCall(ISGetIndices(nest->isglobal.row[i], &bmindices));
2060:       PetscCall(MatGetOwnershipRange(B, &rstart, NULL));
2061:       for (br = 0; br < bm; ++br) {
2062:         PetscInt           row = bmindices[br], brncols, *cols;
2063:         const PetscInt    *brcols;
2064:         const PetscScalar *brcoldata;
2065:         PetscScalar       *vals = NULL;
2066:         PetscCall(MatGetRow(B, br + rstart, &brncols, &brcols, &brcoldata));
2067:         PetscCall(PetscMalloc1(brncols, &cols));
2068:         for (k = 0; k < brncols; k++) cols[k] = bNindices[brcols[k]];
2069:         /*
2070:           Nest blocks are required to be nonoverlapping -- otherwise nest and monolithic index layouts wouldn't match.
2071:           Thus, we could use INSERT_VALUES, but I prefer ADD_VALUES.
2072:          */
2073:         if (a != 1.0) {
2074:           PetscCall(PetscMalloc1(brncols, &vals));
2075:           for (k = 0; k < brncols; k++) vals[k] = a * brcoldata[k];
2076:           PetscCall(MatSetValues(Y, 1, &row, brncols, cols, vals, ADD_VALUES));
2077:           PetscCall(PetscFree(vals));
2078:         } else {
2079:           PetscCall(MatSetValues(Y, 1, &row, brncols, cols, brcoldata, ADD_VALUES));
2080:         }
2081:         PetscCall(MatRestoreRow(B, br + rstart, &brncols, &brcols, &brcoldata));
2082:         PetscCall(PetscFree(cols));
2083:       }
2084:       PetscCall(MatDestroy(&D));
2085:       PetscCall(ISRestoreIndices(nest->isglobal.row[i], &bmindices));
2086:     }
2087:     PetscCall(ISRestoreIndices(bNis, &bNindices));
2088:     PetscCall(ISDestroy(&bNis));
2089:   }
2090:   PetscCall(MatAssemblyBegin(Y, MAT_FINAL_ASSEMBLY));
2091:   PetscCall(MatAssemblyEnd(Y, MAT_FINAL_ASSEMBLY));
2092:   PetscFunctionReturn(PETSC_SUCCESS);
2093: }

2095: static PetscErrorCode MatConvert_Nest_AIJ(Mat A, MatType newtype, MatReuse reuse, Mat *newmat)
2096: {
2097:   Mat_Nest   *nest = (Mat_Nest *)A->data;
2098:   PetscInt    m, n, M, N, i, j, k, *dnnz, *onnz = NULL, rstart, cstart, cend;
2099:   PetscMPIInt size;
2100:   Mat         C;

2102:   PetscFunctionBegin;
2103:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
2104:   if (size == 1) { /* look for a special case with SeqAIJ matrices and strided-1, contiguous, blocks */
2105:     PetscInt  nf;
2106:     PetscBool fast;

2108:     PetscCall(PetscStrcmp(newtype, MATAIJ, &fast));
2109:     if (!fast) PetscCall(PetscStrcmp(newtype, MATSEQAIJ, &fast));
2110:     for (i = 0; i < nest->nr && fast; ++i) {
2111:       for (j = 0; j < nest->nc && fast; ++j) {
2112:         Mat B = nest->m[i][j];
2113:         if (B) {
2114:           PetscCall(PetscObjectTypeCompare((PetscObject)B, MATSEQAIJ, &fast));
2115:           if (!fast) {
2116:             PetscBool istrans;

2118:             PetscCall(PetscObjectTypeCompare((PetscObject)B, MATTRANSPOSEVIRTUAL, &istrans));
2119:             if (istrans) {
2120:               Mat Bt;

2122:               PetscCall(MatTransposeGetMat(B, &Bt));
2123:               PetscCall(PetscObjectTypeCompare((PetscObject)Bt, MATSEQAIJ, &fast));
2124:             } else {
2125:               PetscCall(PetscObjectTypeCompare((PetscObject)B, MATHERMITIANTRANSPOSEVIRTUAL, &istrans));
2126:               if (istrans) {
2127:                 Mat Bt;

2129:                 PetscCall(MatHermitianTransposeGetMat(B, &Bt));
2130:                 PetscCall(PetscObjectTypeCompare((PetscObject)Bt, MATSEQAIJ, &fast));
2131:               }
2132:             }
2133:             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);
2134:           }
2135:         }
2136:       }
2137:     }
2138:     for (i = 0, nf = 0; i < nest->nr && fast; ++i) {
2139:       PetscCall(PetscObjectTypeCompare((PetscObject)nest->isglobal.row[i], ISSTRIDE, &fast));
2140:       if (fast) {
2141:         PetscInt f, s;

2143:         PetscCall(ISStrideGetInfo(nest->isglobal.row[i], &f, &s));
2144:         if (f != nf || s != 1) {
2145:           fast = PETSC_FALSE;
2146:         } else {
2147:           PetscCall(ISGetSize(nest->isglobal.row[i], &f));
2148:           nf += f;
2149:         }
2150:       }
2151:     }
2152:     for (i = 0, nf = 0; i < nest->nc && fast; ++i) {
2153:       PetscCall(PetscObjectTypeCompare((PetscObject)nest->isglobal.col[i], ISSTRIDE, &fast));
2154:       if (fast) {
2155:         PetscInt f, s;

2157:         PetscCall(ISStrideGetInfo(nest->isglobal.col[i], &f, &s));
2158:         if (f != nf || s != 1) {
2159:           fast = PETSC_FALSE;
2160:         } else {
2161:           PetscCall(ISGetSize(nest->isglobal.col[i], &f));
2162:           nf += f;
2163:         }
2164:       }
2165:     }
2166:     if (fast) {
2167:       PetscCall(MatConvert_Nest_SeqAIJ_fast(A, newtype, reuse, newmat));
2168:       PetscFunctionReturn(PETSC_SUCCESS);
2169:     }
2170:   }
2171:   PetscCall(MatGetSize(A, &M, &N));
2172:   PetscCall(MatGetLocalSize(A, &m, &n));
2173:   PetscCall(MatGetOwnershipRangeColumn(A, &cstart, &cend));
2174:   if (reuse == MAT_REUSE_MATRIX) C = *newmat;
2175:   else {
2176:     PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2177:     PetscCall(MatSetType(C, newtype));
2178:     PetscCall(MatSetSizes(C, m, n, M, N));
2179:   }
2180:   PetscCall(PetscMalloc1(2 * m, &dnnz));
2181:   if (m) {
2182:     onnz = dnnz + m;
2183:     for (k = 0; k < m; k++) {
2184:       dnnz[k] = 0;
2185:       onnz[k] = 0;
2186:     }
2187:   }
2188:   for (j = 0; j < nest->nc; ++j) {
2189:     IS              bNis;
2190:     PetscInt        bN;
2191:     const PetscInt *bNindices;
2192:     PetscBool       flg;
2193:     /* Using global column indices and ISAllGather() is not scalable. */
2194:     PetscCall(ISAllGather(nest->isglobal.col[j], &bNis));
2195:     PetscCall(ISGetSize(bNis, &bN));
2196:     PetscCall(ISGetIndices(bNis, &bNindices));
2197:     for (i = 0; i < nest->nr; ++i) {
2198:       PetscSF         bmsf;
2199:       PetscSFNode    *iremote;
2200:       Mat             B = nest->m[i][j], D = NULL;
2201:       PetscInt        bm, *sub_dnnz, *sub_onnz, br;
2202:       const PetscInt *bmindices;
2203:       if (!B) continue;
2204:       PetscCall(ISGetLocalSize(nest->isglobal.row[i], &bm));
2205:       PetscCall(ISGetIndices(nest->isglobal.row[i], &bmindices));
2206:       PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)A), &bmsf));
2207:       PetscCall(PetscMalloc1(bm, &iremote));
2208:       PetscCall(PetscMalloc1(bm, &sub_dnnz));
2209:       PetscCall(PetscMalloc1(bm, &sub_onnz));
2210:       for (k = 0; k < bm; ++k) {
2211:         sub_dnnz[k] = 0;
2212:         sub_onnz[k] = 0;
2213:       }
2214:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATTRANSPOSEVIRTUAL, MATHERMITIANTRANSPOSEVIRTUAL, ""));
2215:       if (flg) {
2216:         PetscTryMethod(B, "MatTransposeGetMat_C", (Mat, Mat *), (B, &D));
2217:         PetscTryMethod(B, "MatHermitianTransposeGetMat_C", (Mat, Mat *), (B, &D));
2218:         PetscCall(MatConvert(B, ((PetscObject)D)->type_name, MAT_INITIAL_MATRIX, &D));
2219:         B = D;
2220:       }
2221:       PetscCall(PetscObjectTypeCompareAny((PetscObject)B, &flg, MATSEQSBAIJ, MATMPISBAIJ, ""));
2222:       if (flg) {
2223:         if (D) PetscCall(MatConvert(D, MATBAIJ, MAT_INPLACE_MATRIX, &D));
2224:         else PetscCall(MatConvert(B, MATBAIJ, MAT_INITIAL_MATRIX, &D));
2225:         B = D;
2226:       }
2227:       /*
2228:        Locate the owners for all of the locally-owned global row indices for this row block.
2229:        These determine the roots of PetscSF used to communicate preallocation data to row owners.
2230:        The roots correspond to the dnnz and onnz entries; thus, there are two roots per row.
2231:        */
2232:       PetscCall(MatGetOwnershipRange(B, &rstart, NULL));
2233:       for (br = 0; br < bm; ++br) {
2234:         PetscInt        row = bmindices[br], brncols, col;
2235:         const PetscInt *brcols;
2236:         PetscInt        rowrel   = 0; /* row's relative index on its owner rank */
2237:         PetscMPIInt     rowowner = 0;
2238:         PetscCall(PetscLayoutFindOwnerIndex(A->rmap, row, &rowowner, &rowrel));
2239:         /* how many roots  */
2240:         iremote[br].rank  = rowowner;
2241:         iremote[br].index = rowrel; /* edge from bmdnnz to dnnz */
2242:         /* get nonzero pattern */
2243:         PetscCall(MatGetRow(B, br + rstart, &brncols, &brcols, NULL));
2244:         for (k = 0; k < brncols; k++) {
2245:           col = bNindices[brcols[k]];
2246:           if (col >= A->cmap->range[rowowner] && col < A->cmap->range[rowowner + 1]) {
2247:             sub_dnnz[br]++;
2248:           } else {
2249:             sub_onnz[br]++;
2250:           }
2251:         }
2252:         PetscCall(MatRestoreRow(B, br + rstart, &brncols, &brcols, NULL));
2253:       }
2254:       PetscCall(MatDestroy(&D));
2255:       PetscCall(ISRestoreIndices(nest->isglobal.row[i], &bmindices));
2256:       /* bsf will have to take care of disposing of bedges. */
2257:       PetscCall(PetscSFSetGraph(bmsf, m, bm, NULL, PETSC_OWN_POINTER, iremote, PETSC_OWN_POINTER));
2258:       PetscCall(PetscSFReduceBegin(bmsf, MPIU_INT, sub_dnnz, dnnz, MPI_SUM));
2259:       PetscCall(PetscSFReduceEnd(bmsf, MPIU_INT, sub_dnnz, dnnz, MPI_SUM));
2260:       PetscCall(PetscSFReduceBegin(bmsf, MPIU_INT, sub_onnz, onnz, MPI_SUM));
2261:       PetscCall(PetscSFReduceEnd(bmsf, MPIU_INT, sub_onnz, onnz, MPI_SUM));
2262:       PetscCall(PetscFree(sub_dnnz));
2263:       PetscCall(PetscFree(sub_onnz));
2264:       PetscCall(PetscSFDestroy(&bmsf));
2265:     }
2266:     PetscCall(ISRestoreIndices(bNis, &bNindices));
2267:     PetscCall(ISDestroy(&bNis));
2268:   }
2269:   /* Resize preallocation if overestimated */
2270:   for (i = 0; i < m; i++) {
2271:     dnnz[i] = PetscMin(dnnz[i], A->cmap->n);
2272:     onnz[i] = PetscMin(onnz[i], A->cmap->N - A->cmap->n);
2273:   }
2274:   PetscCall(MatSeqAIJSetPreallocation(C, 0, dnnz));
2275:   PetscCall(MatMPIAIJSetPreallocation(C, 0, dnnz, 0, onnz));
2276:   PetscCall(PetscFree(dnnz));
2277:   PetscCall(MatAXPY_Dense_Nest(C, 1.0, A));
2278:   if (reuse == MAT_INPLACE_MATRIX) PetscCall(MatHeaderReplace(A, &C));
2279:   else *newmat = C;
2280:   PetscFunctionReturn(PETSC_SUCCESS);
2281: }

2283: static PetscErrorCode MatConvert_Nest_Dense(Mat A, MatType newtype, MatReuse reuse, Mat *newmat)
2284: {
2285:   Mat      B;
2286:   PetscInt m, n, M, N;

2288:   PetscFunctionBegin;
2289:   PetscCall(MatGetSize(A, &M, &N));
2290:   PetscCall(MatGetLocalSize(A, &m, &n));
2291:   if (reuse == MAT_REUSE_MATRIX) {
2292:     B = *newmat;
2293:     PetscCall(MatZeroEntries(B));
2294:   } else {
2295:     PetscCall(MatCreateDense(PetscObjectComm((PetscObject)A), m, PETSC_DECIDE, M, N, NULL, &B));
2296:   }
2297:   PetscCall(MatAXPY_Dense_Nest(B, 1.0, A));
2298:   if (reuse == MAT_INPLACE_MATRIX) PetscCall(MatHeaderReplace(A, &B));
2299:   else if (reuse == MAT_INITIAL_MATRIX) *newmat = B;
2300:   PetscFunctionReturn(PETSC_SUCCESS);
2301: }

2303: static PetscErrorCode MatHasOperation_Nest(Mat mat, MatOperation op, PetscBool *has)
2304: {
2305:   Mat_Nest *bA  = (Mat_Nest *)mat->data;
2306:   PetscBool flg = PETSC_TRUE;

2308:   PetscFunctionBegin;
2309:   *has = PETSC_FALSE;
2310:   if (op == MATOP_MULT || op == MATOP_MULT_ADD || op == MATOP_MULT_TRANSPOSE || op == MATOP_MULT_TRANSPOSE_ADD || op == MATOP_MULT_HERMITIAN_TRANSPOSE || op == MATOP_MULT_HERMITIAN_TRANS_ADD) {
2311:     MatOperation opAdd;

2313:     if (op == MATOP_MULT || op == MATOP_MULT_ADD) opAdd = MATOP_MULT_ADD;
2314:     else if (op == MATOP_MULT_TRANSPOSE || op == MATOP_MULT_TRANSPOSE_ADD) opAdd = MATOP_MULT_TRANSPOSE_ADD;
2315:     else opAdd = MATOP_MULT_HERMITIAN_TRANS_ADD;
2316:     for (PetscInt j = 0; j < bA->nc && flg; j++) {
2317:       for (PetscInt i = 0; i < bA->nr; i++) {
2318:         if (!bA->m[i][j]) continue;
2319:         PetscCall(MatHasOperation(bA->m[i][j], opAdd, &flg));
2320:         if (!flg) break;
2321:       }
2322:     }
2323:   }
2324:   if (flg && ((void **)mat->ops)[op]) *has = PETSC_TRUE;
2325:   PetscFunctionReturn(PETSC_SUCCESS);
2326: }

2328: /*MC
2329:   MATNEST -  "nest" - Matrix type consisting of nested submatrices, each stored separately.

2331:   Level: intermediate

2333:   Notes:
2334:   This matrix type permits scalable use of `PCFIELDSPLIT` and avoids the large memory costs of extracting submatrices.
2335:   It allows the use of symmetric and block formats for parts of multi-physics simulations.
2336:   It is usually used with `DMCOMPOSITE` and `DMCreateMatrix()`

2338:   Each of the submatrices lives on the same MPI communicator as the original nest matrix (though they can have zero
2339:   rows/columns on some processes.) Thus this is not meant for cases where the submatrices live on far fewer processes
2340:   than the nest matrix.

2342: .seealso: [](ch_matrices), `Mat`, `MATNEST`, `MatCreate()`, `MatType`, `MatCreateNest()`, `MatNestSetSubMat()`, `MatNestGetSubMat()`,
2343:           `VecCreateNest()`, `DMCreateMatrix()`, `DMCOMPOSITE`, `MatNestSetVecType()`, `MatNestGetLocalISs()`,
2344:           `MatNestGetISs()`, `MatNestSetSubMats()`, `MatNestGetSubMats()`
2345: M*/
2346: PETSC_EXTERN PetscErrorCode MatCreate_Nest(Mat A)
2347: {
2348:   Mat_Nest *s;

2350:   PetscFunctionBegin;
2351:   PetscCall(PetscNew(&s));
2352:   A->data = (void *)s;

2354:   s->nr            = -1;
2355:   s->nc            = -1;
2356:   s->m             = NULL;
2357:   s->splitassembly = PETSC_FALSE;

2359:   PetscCall(PetscMemzero(A->ops, sizeof(*A->ops)));

2361:   A->ops->mult                      = MatMult_Nest;
2362:   A->ops->multadd                   = MatMultAdd_Nest;
2363:   A->ops->multtranspose             = MatMultTranspose_Nest;
2364:   A->ops->multtransposeadd          = MatMultTransposeAdd_Nest;
2365:   A->ops->transpose                 = MatTranspose_Nest;
2366:   A->ops->multhermitiantranspose    = MatMultHermitianTranspose_Nest;
2367:   A->ops->multhermitiantransposeadd = MatMultHermitianTransposeAdd_Nest;
2368:   A->ops->assemblybegin             = MatAssemblyBegin_Nest;
2369:   A->ops->assemblyend               = MatAssemblyEnd_Nest;
2370:   A->ops->zeroentries               = MatZeroEntries_Nest;
2371:   A->ops->copy                      = MatCopy_Nest;
2372:   A->ops->axpy                      = MatAXPY_Nest;
2373:   A->ops->duplicate                 = MatDuplicate_Nest;
2374:   A->ops->createsubmatrix           = MatCreateSubMatrix_Nest;
2375:   A->ops->destroy                   = MatDestroy_Nest;
2376:   A->ops->view                      = MatView_Nest;
2377:   A->ops->getvecs                   = NULL; /* Use VECNEST by calling MatNestSetVecType(A,VECNEST) */
2378:   A->ops->getlocalsubmatrix         = MatGetLocalSubMatrix_Nest;
2379:   A->ops->restorelocalsubmatrix     = MatRestoreLocalSubMatrix_Nest;
2380:   A->ops->getdiagonal               = MatGetDiagonal_Nest;
2381:   A->ops->diagonalscale             = MatDiagonalScale_Nest;
2382:   A->ops->scale                     = MatScale_Nest;
2383:   A->ops->shift                     = MatShift_Nest;
2384:   A->ops->diagonalset               = MatDiagonalSet_Nest;
2385:   A->ops->setrandom                 = MatSetRandom_Nest;
2386:   A->ops->hasoperation              = MatHasOperation_Nest;

2388:   A->spptr     = NULL;
2389:   A->assembled = PETSC_FALSE;

2391:   /* expose Nest api's */
2392:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMat_C", MatNestGetSubMat_Nest));
2393:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMat_C", MatNestSetSubMat_Nest));
2394:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSubMats_C", MatNestGetSubMats_Nest));
2395:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetSize_C", MatNestGetSize_Nest));
2396:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetISs_C", MatNestGetISs_Nest));
2397:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestGetLocalISs_C", MatNestGetLocalISs_Nest));
2398:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetVecType_C", MatNestSetVecType_Nest));
2399:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatNestSetSubMats_C", MatNestSetSubMats_Nest));
2400:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpiaij_C", MatConvert_Nest_AIJ));
2401:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqaij_C", MatConvert_Nest_AIJ));
2402:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_aij_C", MatConvert_Nest_AIJ));
2403:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_is_C", MatConvert_Nest_IS));
2404:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_mpidense_C", MatConvert_Nest_Dense));
2405:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatConvert_nest_seqdense_C", MatConvert_Nest_Dense));
2406:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_seqdense_C", MatProductSetFromOptions_Nest_Dense));
2407:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatProductSetFromOptions_nest_mpidense_C", MatProductSetFromOptions_Nest_Dense));

2409:   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATNEST));
2410:   PetscFunctionReturn(PETSC_SUCCESS);
2411: }