Actual source code: shell.c

  1: /*
  2:    This provides a simple shell for Fortran (and C programmers) to
  3:   create a very simple matrix class for use with KSP without coding
  4:   much of anything.
  5: */

  7: #include <../src/mat/impls/shell/shell.h>

  9: /*
 10:      Store and scale values on zeroed rows
 11:      xx = [x_1, 0], 0 on zeroed columns
 12: */
 13: static PetscErrorCode MatShellPreZeroRight(Mat A, Vec x, Vec *xx)
 14: {
 15:   Mat_Shell *shell = (Mat_Shell *)A->data;

 17:   PetscFunctionBegin;
 18:   *xx = x;
 19:   if (shell->zrows) {
 20:     PetscCall(VecSet(shell->zvals_w, 0.0));
 21:     PetscCall(VecScatterBegin(shell->zvals_sct_c, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
 22:     PetscCall(VecScatterEnd(shell->zvals_sct_c, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
 23:     PetscCall(VecPointwiseMult(shell->zvals_w, shell->zvals_w, shell->zvals));
 24:   }
 25:   if (shell->zcols) {
 26:     if (!shell->right_work) PetscCall(MatCreateVecs(A, &shell->right_work, NULL));
 27:     PetscCall(VecCopy(x, shell->right_work));
 28:     PetscCall(VecISSet(shell->right_work, shell->zcols, 0.0));
 29:     *xx = shell->right_work;
 30:   }
 31:   PetscFunctionReturn(PETSC_SUCCESS);
 32: }

 34: /* Insert properly diagonally scaled values stored in MatShellPreZeroRight */
 35: static PetscErrorCode MatShellPostZeroLeft(Mat A, Vec x)
 36: {
 37:   Mat_Shell *shell = (Mat_Shell *)A->data;

 39:   PetscFunctionBegin;
 40:   if (shell->zrows) {
 41:     PetscCall(VecScatterBegin(shell->zvals_sct_r, shell->zvals_w, x, INSERT_VALUES, SCATTER_REVERSE));
 42:     PetscCall(VecScatterEnd(shell->zvals_sct_r, shell->zvals_w, x, INSERT_VALUES, SCATTER_REVERSE));
 43:   }
 44:   PetscFunctionReturn(PETSC_SUCCESS);
 45: }

 47: /*
 48:      Store and scale values on zeroed rows
 49:      xx = [x_1, 0], 0 on zeroed rows
 50: */
 51: static PetscErrorCode MatShellPreZeroLeft(Mat A, Vec x, Vec *xx)
 52: {
 53:   Mat_Shell *shell = (Mat_Shell *)A->data;

 55:   PetscFunctionBegin;
 56:   *xx = NULL;
 57:   if (!shell->zrows) {
 58:     *xx = x;
 59:   } else {
 60:     if (!shell->left_work) PetscCall(MatCreateVecs(A, NULL, &shell->left_work));
 61:     PetscCall(VecCopy(x, shell->left_work));
 62:     PetscCall(VecSet(shell->zvals_w, 0.0));
 63:     PetscCall(VecScatterBegin(shell->zvals_sct_r, shell->zvals_w, shell->left_work, INSERT_VALUES, SCATTER_REVERSE));
 64:     PetscCall(VecScatterEnd(shell->zvals_sct_r, shell->zvals_w, shell->left_work, INSERT_VALUES, SCATTER_REVERSE));
 65:     PetscCall(VecScatterBegin(shell->zvals_sct_r, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
 66:     PetscCall(VecScatterEnd(shell->zvals_sct_r, x, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
 67:     PetscCall(VecPointwiseMult(shell->zvals_w, shell->zvals_w, shell->zvals));
 68:     *xx = shell->left_work;
 69:   }
 70:   PetscFunctionReturn(PETSC_SUCCESS);
 71: }

 73: /* Zero zero-columns contributions, sum contributions from properly scaled values stored in MatShellPreZeroLeft */
 74: static PetscErrorCode MatShellPostZeroRight(Mat A, Vec x)
 75: {
 76:   Mat_Shell *shell = (Mat_Shell *)A->data;

 78:   PetscFunctionBegin;
 79:   if (shell->zcols) PetscCall(VecISSet(x, shell->zcols, 0.0));
 80:   if (shell->zrows) {
 81:     PetscCall(VecScatterBegin(shell->zvals_sct_c, shell->zvals_w, x, ADD_VALUES, SCATTER_REVERSE));
 82:     PetscCall(VecScatterEnd(shell->zvals_sct_c, shell->zvals_w, x, ADD_VALUES, SCATTER_REVERSE));
 83:   }
 84:   PetscFunctionReturn(PETSC_SUCCESS);
 85: }

 87: /*
 88:       xx = diag(left)*x
 89: */
 90: static PetscErrorCode MatShellPreScaleLeft(Mat A, Vec x, Vec *xx, PetscBool conjugate)
 91: {
 92:   Mat_Shell *shell = (Mat_Shell *)A->data;

 94:   PetscFunctionBegin;
 95:   *xx = NULL;
 96:   if (!shell->left) {
 97:     *xx = x;
 98:   } else {
 99:     if (!shell->left_work) PetscCall(VecDuplicate(shell->left, &shell->left_work));
100:     if (conjugate) { /* get arrays because there is no VecPointwiseMultConj() */
101:       PetscInt           i, m;
102:       const PetscScalar *d, *xarray;
103:       PetscScalar       *w;
104:       PetscCall(VecGetLocalSize(x, &m));
105:       PetscCall(VecGetArrayRead(shell->left, &d));
106:       PetscCall(VecGetArrayRead(x, &xarray));
107:       PetscCall(VecGetArrayWrite(shell->left_work, &w));
108:       for (i = 0; i < m; i++) w[i] = PetscConj(d[i]) * xarray[i];
109:       PetscCall(VecRestoreArrayRead(shell->dshift, &d));
110:       PetscCall(VecRestoreArrayRead(x, &xarray));
111:       PetscCall(VecRestoreArrayWrite(shell->left_work, &w));
112:     } else PetscCall(VecPointwiseMult(shell->left_work, x, shell->left));
113:     *xx = shell->left_work;
114:   }
115:   PetscFunctionReturn(PETSC_SUCCESS);
116: }

118: /*
119:      xx = diag(right)*x
120: */
121: static PetscErrorCode MatShellPreScaleRight(Mat A, Vec x, Vec *xx)
122: {
123:   Mat_Shell *shell = (Mat_Shell *)A->data;

125:   PetscFunctionBegin;
126:   *xx = NULL;
127:   if (!shell->right) {
128:     *xx = x;
129:   } else {
130:     if (!shell->right_work) PetscCall(VecDuplicate(shell->right, &shell->right_work));
131:     PetscCall(VecPointwiseMult(shell->right_work, x, shell->right));
132:     *xx = shell->right_work;
133:   }
134:   PetscFunctionReturn(PETSC_SUCCESS);
135: }

137: /*
138:     x = diag(left)*x
139: */
140: static PetscErrorCode MatShellPostScaleLeft(Mat A, Vec x)
141: {
142:   Mat_Shell *shell = (Mat_Shell *)A->data;

144:   PetscFunctionBegin;
145:   if (shell->left) PetscCall(VecPointwiseMult(x, x, shell->left));
146:   PetscFunctionReturn(PETSC_SUCCESS);
147: }

149: /*
150:     x = diag(right)*x
151: */
152: static PetscErrorCode MatShellPostScaleRight(Mat A, Vec x, PetscBool conjugate)
153: {
154:   Mat_Shell *shell = (Mat_Shell *)A->data;

156:   PetscFunctionBegin;
157:   if (shell->right) {
158:     if (conjugate) { /* get arrays because there is no VecPointwiseMultConj() */
159:       PetscInt           i, m;
160:       const PetscScalar *d;
161:       PetscScalar       *xarray;
162:       PetscCall(VecGetLocalSize(x, &m));
163:       PetscCall(VecGetArrayRead(shell->right, &d));
164:       PetscCall(VecGetArray(x, &xarray));
165:       for (i = 0; i < m; i++) xarray[i] = PetscConj(d[i]) * xarray[i];
166:       PetscCall(VecRestoreArrayRead(shell->dshift, &d));
167:       PetscCall(VecRestoreArray(x, &xarray));
168:     } else PetscCall(VecPointwiseMult(x, x, shell->right));
169:   }
170:   PetscFunctionReturn(PETSC_SUCCESS);
171: }

173: /*
174:          Y = vscale*Y + diag(dshift)*X + vshift*X

176:          On input Y already contains A*x

178:          If conjugate=PETSC_TRUE then vscale, dshift, and vshift are conjugated
179: */
180: static PetscErrorCode MatShellShiftAndScale(Mat A, Vec X, Vec Y, PetscBool conjugate)
181: {
182:   Mat_Shell  *shell  = (Mat_Shell *)A->data;
183:   PetscScalar vscale = conjugate ? PetscConj(shell->vscale) : shell->vscale;
184:   PetscScalar vshift = conjugate ? PetscConj(shell->vshift) : shell->vshift;

186:   PetscFunctionBegin;
187:   if (shell->dshift) { /* get arrays because there is no VecPointwiseMultAdd() */
188:     PetscInt           i, m;
189:     const PetscScalar *x, *d;
190:     PetscScalar       *y;
191:     PetscCall(VecGetLocalSize(X, &m));
192:     PetscCall(VecGetArrayRead(shell->dshift, &d));
193:     PetscCall(VecGetArrayRead(X, &x));
194:     PetscCall(VecGetArray(Y, &y));
195:     if (conjugate)
196:       for (i = 0; i < m; i++) y[i] = vscale * y[i] + PetscConj(d[i]) * x[i];
197:     else
198:       for (i = 0; i < m; i++) y[i] = vscale * y[i] + d[i] * x[i];
199:     PetscCall(VecRestoreArrayRead(shell->dshift, &d));
200:     PetscCall(VecRestoreArrayRead(X, &x));
201:     PetscCall(VecRestoreArray(Y, &y));
202:   } else {
203:     PetscCall(VecScale(Y, vscale));
204:   }
205:   if (vshift != 0.0) PetscCall(VecAXPY(Y, vshift, X)); /* if test is for non-square matrices */
206:   PetscFunctionReturn(PETSC_SUCCESS);
207: }

209: static PetscErrorCode MatShellGetContext_Shell(Mat mat, PetscCtxRt ctx)
210: {
211:   Mat_Shell *shell = (Mat_Shell *)mat->data;

213:   PetscFunctionBegin;
214:   if (shell->ctxcontainer) PetscCall(PetscContainerGetPointer(shell->ctxcontainer, ctx));
215:   else *(void **)ctx = NULL;
216:   PetscFunctionReturn(PETSC_SUCCESS);
217: }

219: /*@
220:   MatShellGetContext - Returns the user-provided context associated with a `MATSHELL` shell matrix.

222:   Not Collective

224:   Input Parameter:
225: . mat - the matrix, should have been created with `MatCreateShell()`

227:   Output Parameter:
228: . ctx - the user provided context

230:   Level: advanced

232:   Fortran Notes:
233:   This only works when the context is a Fortran derived type or a `PetscObject`. Declare `ctx` with
234: .vb
235:   type(tUsertype), pointer :: ctx
236: .ve

238: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellSetOperation()`, `MatShellSetContext()`
239: @*/
240: PetscErrorCode MatShellGetContext(Mat mat, PetscCtxRt ctx)
241: {
242:   PetscFunctionBegin;
244:   PetscAssertPointer(ctx, 2);
245:   PetscUseMethod(mat, "MatShellGetContext_C", (Mat, void *), (mat, ctx));
246:   PetscFunctionReturn(PETSC_SUCCESS);
247: }

249: static PetscErrorCode MatZeroRowsColumns_Local_Shell(Mat mat, PetscInt nr, PetscInt rows[], PetscInt nc, PetscInt cols[], PetscScalar diag, PetscBool rc)
250: {
251:   Mat_Shell      *shell = (Mat_Shell *)mat->data;
252:   Vec             x = NULL, b = NULL;
253:   IS              is1, is2;
254:   const PetscInt *ridxs;
255:   PetscInt       *idxs, *gidxs;
256:   PetscInt        cum, rst, cst, i;

258:   PetscFunctionBegin;
259:   if (!shell->zvals) PetscCall(MatCreateVecs(mat, NULL, &shell->zvals));
260:   if (!shell->zvals_w) PetscCall(VecDuplicate(shell->zvals, &shell->zvals_w));
261:   PetscCall(MatGetOwnershipRange(mat, &rst, NULL));
262:   PetscCall(MatGetOwnershipRangeColumn(mat, &cst, NULL));

264:   /* Expand/create index set of zeroed rows */
265:   PetscCall(PetscMalloc1(nr, &idxs));
266:   for (i = 0; i < nr; i++) idxs[i] = rows[i] + rst;
267:   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), nr, idxs, PETSC_OWN_POINTER, &is1));
268:   PetscCall(ISSort(is1));
269:   PetscCall(VecISSet(shell->zvals, is1, diag));
270:   if (shell->zrows) {
271:     PetscCall(ISSum(shell->zrows, is1, &is2));
272:     PetscCall(ISDestroy(&shell->zrows));
273:     PetscCall(ISDestroy(&is1));
274:     shell->zrows = is2;
275:   } else shell->zrows = is1;

277:   /* Create scatters for diagonal values communications */
278:   PetscCall(VecScatterDestroy(&shell->zvals_sct_c));
279:   PetscCall(VecScatterDestroy(&shell->zvals_sct_r));

281:   /* row scatter: from/to left vector */
282:   PetscCall(MatCreateVecs(mat, &x, &b));
283:   PetscCall(VecScatterCreate(b, shell->zrows, shell->zvals_w, shell->zrows, &shell->zvals_sct_r));

285:   /* col scatter: from right vector to left vector */
286:   PetscCall(ISGetIndices(shell->zrows, &ridxs));
287:   PetscCall(ISGetLocalSize(shell->zrows, &nr));
288:   PetscCall(PetscMalloc1(nr, &gidxs));
289:   for (i = 0, cum = 0; i < nr; i++) {
290:     if (ridxs[i] >= mat->cmap->N) continue;
291:     gidxs[cum] = ridxs[i];
292:     cum++;
293:   }
294:   PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), cum, gidxs, PETSC_OWN_POINTER, &is1));
295:   PetscCall(VecScatterCreate(x, is1, shell->zvals_w, is1, &shell->zvals_sct_c));
296:   PetscCall(ISDestroy(&is1));
297:   PetscCall(VecDestroy(&x));
298:   PetscCall(VecDestroy(&b));

300:   /* Expand/create index set of zeroed columns */
301:   if (rc) {
302:     PetscCall(PetscMalloc1(nc, &idxs));
303:     for (i = 0; i < nc; i++) idxs[i] = cols[i] + cst;
304:     PetscCall(ISCreateGeneral(PetscObjectComm((PetscObject)mat), nc, idxs, PETSC_OWN_POINTER, &is1));
305:     PetscCall(ISSort(is1));
306:     if (shell->zcols) {
307:       PetscCall(ISSum(shell->zcols, is1, &is2));
308:       PetscCall(ISDestroy(&shell->zcols));
309:       PetscCall(ISDestroy(&is1));
310:       shell->zcols = is2;
311:     } else shell->zcols = is1;
312:   }
313:   PetscFunctionReturn(PETSC_SUCCESS);
314: }

316: static PetscErrorCode MatZeroRows_Shell(Mat mat, PetscInt n, const PetscInt rows[], PetscScalar diag, Vec x, Vec b)
317: {
318:   Mat_Shell *shell = (Mat_Shell *)mat->data;
319:   PetscInt   nr, *lrows;

321:   PetscFunctionBegin;
322:   if (x && b) {
323:     Vec          xt;
324:     PetscScalar *vals;
325:     PetscInt    *gcols, i, st, nl, nc;

327:     PetscCall(PetscMalloc1(n, &gcols));
328:     for (i = 0, nc = 0; i < n; i++)
329:       if (rows[i] < mat->cmap->N) gcols[nc++] = rows[i];

331:     PetscCall(MatCreateVecs(mat, &xt, NULL));
332:     PetscCall(VecCopy(x, xt));
333:     PetscCall(PetscCalloc1(nc, &vals));
334:     PetscCall(VecSetValues(xt, nc, gcols, vals, INSERT_VALUES)); /* xt = [x1, 0] */
335:     PetscCall(PetscFree(vals));
336:     PetscCall(VecAssemblyBegin(xt));
337:     PetscCall(VecAssemblyEnd(xt));
338:     PetscCall(VecAYPX(xt, -1.0, x)); /* xt = [0, x2] */

340:     PetscCall(VecGetOwnershipRange(xt, &st, NULL));
341:     PetscCall(VecGetLocalSize(xt, &nl));
342:     PetscCall(VecGetArray(xt, &vals));
343:     for (i = 0; i < nl; i++) {
344:       PetscInt g = i + st;
345:       if (g > mat->rmap->N) continue;
346:       if (PetscAbsScalar(vals[i]) == 0.0) continue;
347:       PetscCall(VecSetValue(b, g, diag * vals[i], INSERT_VALUES));
348:     }
349:     PetscCall(VecRestoreArray(xt, &vals));
350:     PetscCall(VecAssemblyBegin(b));
351:     PetscCall(VecAssemblyEnd(b)); /* b  = [b1, x2 * diag] */
352:     PetscCall(VecDestroy(&xt));
353:     PetscCall(PetscFree(gcols));
354:   }
355:   PetscCall(PetscLayoutMapLocal(mat->rmap, n, rows, &nr, &lrows, NULL));
356:   PetscCall(MatZeroRowsColumns_Local_Shell(mat, nr, lrows, 0, NULL, diag, PETSC_FALSE));
357:   if (shell->axpy) PetscCall(MatZeroRows(shell->axpy, n, rows, 0.0, NULL, NULL));
358:   PetscCall(PetscFree(lrows));
359:   PetscFunctionReturn(PETSC_SUCCESS);
360: }

362: static PetscErrorCode MatZeroRowsColumns_Shell(Mat mat, PetscInt n, const PetscInt rowscols[], PetscScalar diag, Vec x, Vec b)
363: {
364:   Mat_Shell *shell = (Mat_Shell *)mat->data;
365:   PetscInt  *lrows, *lcols;
366:   PetscInt   nr, nc;
367:   PetscBool  congruent;

369:   PetscFunctionBegin;
370:   if (x && b) {
371:     Vec          xt, bt;
372:     PetscScalar *vals;
373:     PetscInt    *grows, *gcols, i, st, nl;

375:     PetscCall(PetscMalloc2(n, &grows, n, &gcols));
376:     for (i = 0, nr = 0; i < n; i++)
377:       if (rowscols[i] < mat->rmap->N) grows[nr++] = rowscols[i];
378:     for (i = 0, nc = 0; i < n; i++)
379:       if (rowscols[i] < mat->cmap->N) gcols[nc++] = rowscols[i];
380:     PetscCall(PetscCalloc1(n, &vals));

382:     PetscCall(MatCreateVecs(mat, &xt, &bt));
383:     PetscCall(VecCopy(x, xt));
384:     PetscCall(VecSetValues(xt, nc, gcols, vals, INSERT_VALUES)); /* xt = [x1, 0] */
385:     PetscCall(VecAssemblyBegin(xt));
386:     PetscCall(VecAssemblyEnd(xt));
387:     PetscCall(VecAXPY(xt, -1.0, x));                             /* xt = [0, -x2] */
388:     PetscCall(MatMult(mat, xt, bt));                             /* bt = [-A12*x2,-A22*x2] */
389:     PetscCall(VecSetValues(bt, nr, grows, vals, INSERT_VALUES)); /* bt = [-A12*x2,0] */
390:     PetscCall(VecAssemblyBegin(bt));
391:     PetscCall(VecAssemblyEnd(bt));
392:     PetscCall(VecAXPY(b, 1.0, bt));                              /* b  = [b1 - A12*x2, b2] */
393:     PetscCall(VecSetValues(bt, nr, grows, vals, INSERT_VALUES)); /* b  = [b1 - A12*x2, 0] */
394:     PetscCall(VecAssemblyBegin(bt));
395:     PetscCall(VecAssemblyEnd(bt));
396:     PetscCall(PetscFree(vals));

398:     PetscCall(VecGetOwnershipRange(xt, &st, NULL));
399:     PetscCall(VecGetLocalSize(xt, &nl));
400:     PetscCall(VecGetArray(xt, &vals));
401:     for (i = 0; i < nl; i++) {
402:       PetscInt g = i + st;
403:       if (g > mat->rmap->N) continue;
404:       if (PetscAbsScalar(vals[i]) == 0.0) continue;
405:       PetscCall(VecSetValue(b, g, -diag * vals[i], INSERT_VALUES));
406:     }
407:     PetscCall(VecRestoreArray(xt, &vals));
408:     PetscCall(VecAssemblyBegin(b));
409:     PetscCall(VecAssemblyEnd(b)); /* b  = [b1 - A12*x2, x2 * diag] */
410:     PetscCall(VecDestroy(&xt));
411:     PetscCall(VecDestroy(&bt));
412:     PetscCall(PetscFree2(grows, gcols));
413:   }
414:   PetscCall(PetscLayoutMapLocal(mat->rmap, n, rowscols, &nr, &lrows, NULL));
415:   PetscCall(MatHasCongruentLayouts(mat, &congruent));
416:   if (congruent) {
417:     nc    = nr;
418:     lcols = lrows;
419:   } else { /* MatZeroRowsColumns implicitly assumes the rowscols indices are for a square matrix, here we handle a more general case */
420:     PetscInt i, nt, *t;

422:     PetscCall(PetscMalloc1(n, &t));
423:     for (i = 0, nt = 0; i < n; i++)
424:       if (rowscols[i] < mat->cmap->N) t[nt++] = rowscols[i];
425:     PetscCall(PetscLayoutMapLocal(mat->cmap, nt, t, &nc, &lcols, NULL));
426:     PetscCall(PetscFree(t));
427:   }
428:   PetscCall(MatZeroRowsColumns_Local_Shell(mat, nr, lrows, nc, lcols, diag, PETSC_TRUE));
429:   if (!congruent) PetscCall(PetscFree(lcols));
430:   PetscCall(PetscFree(lrows));
431:   if (shell->axpy) PetscCall(MatZeroRowsColumns(shell->axpy, n, rowscols, 0.0, NULL, NULL));
432:   PetscFunctionReturn(PETSC_SUCCESS);
433: }

435: static PetscErrorCode MatDestroy_Shell(Mat mat)
436: {
437:   Mat_Shell              *shell = (Mat_Shell *)mat->data;
438:   MatShellMatFunctionList matmat;

440:   PetscFunctionBegin;
441:   if (shell->ops->destroy) PetscCall((*shell->ops->destroy)(mat));
442:   PetscCall(PetscMemzero(shell->ops, sizeof(struct _MatShellOps)));
443:   PetscCall(VecDestroy(&shell->left));
444:   PetscCall(VecDestroy(&shell->right));
445:   PetscCall(VecDestroy(&shell->dshift));
446:   PetscCall(VecDestroy(&shell->left_work));
447:   PetscCall(VecDestroy(&shell->right_work));
448:   PetscCall(VecDestroy(&shell->left_add_work));
449:   PetscCall(VecDestroy(&shell->right_add_work));
450:   PetscCall(VecDestroy(&shell->axpy_left));
451:   PetscCall(VecDestroy(&shell->axpy_right));
452:   PetscCall(MatDestroy(&shell->axpy));
453:   PetscCall(VecDestroy(&shell->zvals_w));
454:   PetscCall(VecDestroy(&shell->zvals));
455:   PetscCall(VecScatterDestroy(&shell->zvals_sct_c));
456:   PetscCall(VecScatterDestroy(&shell->zvals_sct_r));
457:   PetscCall(ISDestroy(&shell->zrows));
458:   PetscCall(ISDestroy(&shell->zcols));

460:   matmat = shell->matmat;
461:   while (matmat) {
462:     MatShellMatFunctionList next = matmat->next;

464:     PetscCall(PetscObjectComposeFunction((PetscObject)mat, matmat->composedname, NULL));
465:     PetscCall(PetscFree(matmat->composedname));
466:     PetscCall(PetscFree(matmat->resultname));
467:     PetscCall(PetscFree(matmat));
468:     matmat = next;
469:   }
470:   PetscCall(MatShellSetContext(mat, NULL));
471:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellGetContext_C", NULL));
472:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetContext_C", NULL));
473:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetContextDestroy_C", NULL));
474:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetVecType_C", NULL));
475:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetManageScalingShifts_C", NULL));
476:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellGetScalingShifts_C", NULL));
477:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetOperation_C", NULL));
478:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellGetOperation_C", NULL));
479:   PetscCall(PetscObjectComposeFunction((PetscObject)mat, "MatShellSetMatProductOperation_C", NULL));
480:   PetscCall(PetscFree(mat->data));
481:   PetscFunctionReturn(PETSC_SUCCESS);
482: }

484: typedef struct {
485:   PetscErrorCode (*numeric)(Mat, Mat, Mat, void *);
486:   PetscCtxDestroyFn *destroy;
487:   void              *ctx;
488:   Mat                B;
489:   Mat                Bt;
490:   Mat                axpy;
491: } MatProductCtx_MatMatShell;

493: static PetscErrorCode MatProductCtxDestroy_MatMatShell(PetscCtxRt data)
494: {
495:   MatProductCtx_MatMatShell *mmdata = *(MatProductCtx_MatMatShell **)data;

497:   PetscFunctionBegin;
498:   if (mmdata->destroy) PetscCall((*mmdata->destroy)(&mmdata->ctx));
499:   PetscCall(MatDestroy(&mmdata->B));
500:   PetscCall(MatDestroy(&mmdata->Bt));
501:   PetscCall(MatDestroy(&mmdata->axpy));
502:   PetscCall(PetscFree(mmdata));
503:   PetscFunctionReturn(PETSC_SUCCESS);
504: }

506: static PetscErrorCode MatProductNumeric_Shell_X(Mat D)
507: {
508:   Mat_Product               *product;
509:   Mat                        A, B;
510:   MatProductCtx_MatMatShell *mdata;
511:   Mat_Shell                 *shell;
512:   PetscBool                  useBmdata = PETSC_FALSE, newB = PETSC_TRUE;
513:   PetscErrorCode (*stashsym)(Mat), (*stashnum)(Mat);

515:   PetscFunctionBegin;
516:   MatCheckProduct(D, 1);
517:   product = D->product;
518:   PetscCheck(product->data, PetscObjectComm((PetscObject)D), PETSC_ERR_PLIB, "Product data empty");
519:   A     = product->A;
520:   B     = product->B;
521:   mdata = (MatProductCtx_MatMatShell *)product->data;
522:   PetscCheck(mdata->numeric, PetscObjectComm((PetscObject)D), PETSC_ERR_PLIB, "Missing numeric operation");
523:   shell    = (Mat_Shell *)A->data;
524:   stashsym = D->ops->productsymbolic;
525:   stashnum = D->ops->productnumeric;
526:   if (shell->managescalingshifts) {
527:     PetscCheck(!shell->zcols && !shell->zrows, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProduct not supported with zeroed rows/columns");
528:     if (shell->right || shell->left) {
529:       useBmdata = PETSC_TRUE;
530:       if (!mdata->B) {
531:         PetscCall(MatDuplicate(B, MAT_SHARE_NONZERO_PATTERN, &mdata->B));
532:       } else {
533:         newB = PETSC_FALSE;
534:       }
535:       PetscCall(MatCopy(B, mdata->B, SAME_NONZERO_PATTERN));
536:     }
537:     switch (product->type) {
538:     case MATPRODUCT_AB: /* s L A R B + v L R B + L D R B */
539:       if (shell->right) PetscCall(MatDiagonalScale(mdata->B, shell->right, NULL));
540:       break;
541:     case MATPRODUCT_AtB: /* s R A^t L B + v R L B + R D L B */
542:       if (shell->left) PetscCall(MatDiagonalScale(mdata->B, shell->left, NULL));
543:       break;
544:     case MATPRODUCT_ABt: /* s L A R B^t + v L R B^t + L D R B^t */
545:       if (shell->right) PetscCall(MatDiagonalScale(mdata->B, NULL, shell->right));
546:       break;
547:     case MATPRODUCT_RARt: /* s B L A R B^t + v B L R B^t + B L D R B^t */
548:       if (shell->right && shell->left) {
549:         PetscBool flg;

551:         PetscCall(VecEqual(shell->right, shell->left, &flg));
552:         PetscCheck(flg, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices because left scaling != from right scaling", MatProductTypes[product->type], ((PetscObject)A)->type_name,
553:                    ((PetscObject)B)->type_name);
554:       }
555:       if (shell->right) PetscCall(MatDiagonalScale(mdata->B, NULL, shell->right));
556:       break;
557:     case MATPRODUCT_PtAP: /* s B^t L A R B + v B^t L R B + B^t L D R B */
558:       if (shell->right && shell->left) {
559:         PetscBool flg;

561:         PetscCall(VecEqual(shell->right, shell->left, &flg));
562:         PetscCheck(flg, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices because left scaling != from right scaling", MatProductTypes[product->type], ((PetscObject)A)->type_name,
563:                    ((PetscObject)B)->type_name);
564:       }
565:       if (shell->right) PetscCall(MatDiagonalScale(mdata->B, shell->right, NULL));
566:       break;
567:     default:
568:       SETERRQ(PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices", MatProductTypes[product->type], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name);
569:     }
570:   }
571:   /* allow the user to call MatMat operations on D */
572:   D->product              = NULL;
573:   D->ops->productsymbolic = NULL;
574:   D->ops->productnumeric  = NULL;

576:   PetscCall((*mdata->numeric)(A, useBmdata ? mdata->B : B, D, mdata->ctx));

578:   /* clear any leftover user data and restore D pointers */
579:   PetscCall(MatProductClear(D));
580:   D->ops->productsymbolic = stashsym;
581:   D->ops->productnumeric  = stashnum;
582:   D->product              = product;

584:   if (shell->managescalingshifts) {
585:     PetscCall(MatScale(D, shell->vscale));
586:     switch (product->type) {
587:     case MATPRODUCT_AB:  /* s L A R B + v L R B + L D R B */
588:     case MATPRODUCT_ABt: /* s L A R B^t + v L R B^t + L D R B^t */
589:       if (shell->left) {
590:         PetscCall(MatDiagonalScale(D, shell->left, NULL));
591:         if (shell->dshift || shell->vshift != 0.0) {
592:           if (!shell->left_work) PetscCall(MatCreateVecs(A, NULL, &shell->left_work));
593:           if (shell->dshift) {
594:             PetscCall(VecCopy(shell->dshift, shell->left_work));
595:             PetscCall(VecShift(shell->left_work, shell->vshift));
596:             PetscCall(VecPointwiseMult(shell->left_work, shell->left_work, shell->left));
597:           } else {
598:             PetscCall(VecSet(shell->left_work, shell->vshift));
599:           }
600:           if (product->type == MATPRODUCT_ABt) {
601:             MatReuse     reuse = mdata->Bt ? MAT_REUSE_MATRIX : MAT_INITIAL_MATRIX;
602:             MatStructure str   = mdata->Bt ? SUBSET_NONZERO_PATTERN : DIFFERENT_NONZERO_PATTERN;

604:             PetscCall(MatTranspose(mdata->B, reuse, &mdata->Bt));
605:             PetscCall(MatDiagonalScale(mdata->Bt, shell->left_work, NULL));
606:             PetscCall(MatAXPY(D, 1.0, mdata->Bt, str));
607:           } else {
608:             MatStructure str = newB ? DIFFERENT_NONZERO_PATTERN : SUBSET_NONZERO_PATTERN;

610:             PetscCall(MatDiagonalScale(mdata->B, shell->left_work, NULL));
611:             PetscCall(MatAXPY(D, 1.0, mdata->B, str));
612:           }
613:         }
614:       }
615:       break;
616:     case MATPRODUCT_AtB: /* s R A^t L B + v R L B + R D L B */
617:       if (shell->right) {
618:         PetscCall(MatDiagonalScale(D, shell->right, NULL));
619:         if (shell->dshift || shell->vshift != 0.0) {
620:           MatStructure str = newB ? DIFFERENT_NONZERO_PATTERN : SUBSET_NONZERO_PATTERN;

622:           if (!shell->right_work) PetscCall(MatCreateVecs(A, &shell->right_work, NULL));
623:           if (shell->dshift) {
624:             PetscCall(VecCopy(shell->dshift, shell->right_work));
625:             PetscCall(VecShift(shell->right_work, shell->vshift));
626:             PetscCall(VecPointwiseMult(shell->right_work, shell->right_work, shell->right));
627:           } else {
628:             PetscCall(VecSet(shell->right_work, shell->vshift));
629:           }
630:           PetscCall(MatDiagonalScale(mdata->B, shell->right_work, NULL));
631:           PetscCall(MatAXPY(D, 1.0, mdata->B, str));
632:         }
633:       }
634:       break;
635:     case MATPRODUCT_PtAP: /* s B^t L A R B + v B^t L R B + B^t L D R B */
636:     case MATPRODUCT_RARt: /* s B L A R B^t + v B L R B^t + B L D R B^t */
637:       PetscCheck(!shell->dshift && shell->vshift == 0.0, PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices with diagonal shift", MatProductTypes[product->type], ((PetscObject)A)->type_name,
638:                  ((PetscObject)B)->type_name);
639:       break;
640:     default:
641:       SETERRQ(PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices", MatProductTypes[product->type], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name);
642:     }
643:     if (shell->axpy && shell->axpy_vscale != 0.0) {
644:       Mat              X;
645:       PetscObjectState axpy_state;
646:       MatStructure     str = DIFFERENT_NONZERO_PATTERN; /* not sure it is safe to ever use SUBSET_NONZERO_PATTERN */

648:       PetscCall(MatShellGetContext(shell->axpy, &X));
649:       PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
650:       PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
651:       if (!mdata->axpy) {
652:         str = DIFFERENT_NONZERO_PATTERN;
653:         PetscCall(MatProductCreate(shell->axpy, B, NULL, &mdata->axpy));
654:         PetscCall(MatProductSetType(mdata->axpy, product->type));
655:         PetscCall(MatProductSetFromOptions(mdata->axpy));
656:         PetscCall(MatProductSymbolic(mdata->axpy));
657:       } else { /* May be that shell->axpy has changed */
658:         PetscBool flg;

660:         PetscCall(MatProductReplaceMats(shell->axpy, B, NULL, mdata->axpy));
661:         PetscCall(MatHasOperation(mdata->axpy, MATOP_PRODUCTSYMBOLIC, &flg));
662:         if (!flg) {
663:           str = DIFFERENT_NONZERO_PATTERN;
664:           PetscCall(MatProductSetFromOptions(mdata->axpy));
665:           PetscCall(MatProductSymbolic(mdata->axpy));
666:         }
667:       }
668:       PetscCall(MatProductNumeric(mdata->axpy));
669:       PetscCall(MatAXPY(D, shell->axpy_vscale, mdata->axpy, str));
670:     }
671:   }
672:   PetscFunctionReturn(PETSC_SUCCESS);
673: }

675: static PetscErrorCode MatProductSymbolic_Shell_X(Mat D)
676: {
677:   Mat_Product               *product;
678:   Mat                        A, B;
679:   MatShellMatFunctionList    matmat;
680:   Mat_Shell                 *shell;
681:   PetscBool                  flg = PETSC_FALSE;
682:   char                       composedname[256];
683:   MatProductCtx_MatMatShell *mdata;

685:   PetscFunctionBegin;
686:   MatCheckProduct(D, 1);
687:   product = D->product;
688:   PetscCheck(!product->data, PetscObjectComm((PetscObject)D), PETSC_ERR_PLIB, "Product data not empty");
689:   A      = product->A;
690:   B      = product->B;
691:   shell  = (Mat_Shell *)A->data;
692:   matmat = shell->matmat;
693:   PetscCall(PetscSNPrintf(composedname, sizeof(composedname), "MatProductSetFromOptions_%s_%s_C", ((PetscObject)A)->type_name, ((PetscObject)B)->type_name));
694:   while (matmat) {
695:     PetscCall(PetscStrcmp(composedname, matmat->composedname, &flg));
696:     flg = (PetscBool)(flg && (matmat->ptype == product->type));
697:     if (flg) break;
698:     matmat = matmat->next;
699:   }
700:   PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Composedname \"%s\" for product type %s not found", composedname, MatProductTypes[product->type]);
701:   switch (product->type) {
702:   case MATPRODUCT_AB:
703:     PetscCall(MatSetSizes(D, A->rmap->n, B->cmap->n, A->rmap->N, B->cmap->N));
704:     break;
705:   case MATPRODUCT_AtB:
706:     PetscCall(MatSetSizes(D, A->cmap->n, B->cmap->n, A->cmap->N, B->cmap->N));
707:     break;
708:   case MATPRODUCT_ABt:
709:     PetscCall(MatSetSizes(D, A->rmap->n, B->rmap->n, A->rmap->N, B->rmap->N));
710:     break;
711:   case MATPRODUCT_RARt:
712:     PetscCall(MatSetSizes(D, B->rmap->n, B->rmap->n, B->rmap->N, B->rmap->N));
713:     break;
714:   case MATPRODUCT_PtAP:
715:     PetscCall(MatSetSizes(D, B->cmap->n, B->cmap->n, B->cmap->N, B->cmap->N));
716:     break;
717:   default:
718:     SETERRQ(PetscObjectComm((PetscObject)D), PETSC_ERR_SUP, "MatProductSymbolic type %s not supported for %s and %s matrices", MatProductTypes[product->type], ((PetscObject)A)->type_name, ((PetscObject)B)->type_name);
719:   }
720:   /* respect users who passed in a matrix for which resultname is the base type */
721:   if (matmat->resultname) {
722:     PetscCall(PetscObjectBaseTypeCompare((PetscObject)D, matmat->resultname, &flg));
723:     if (!flg) PetscCall(MatSetType(D, matmat->resultname));
724:   }
725:   /* If matrix type was not set or different, we need to reset this pointers */
726:   D->ops->productsymbolic = MatProductSymbolic_Shell_X;
727:   D->ops->productnumeric  = MatProductNumeric_Shell_X;
728:   /* attach product data */
729:   PetscCall(PetscNew(&mdata));
730:   mdata->numeric = matmat->numeric;
731:   mdata->destroy = matmat->destroy;
732:   if (matmat->symbolic) {
733:     PetscCall((*matmat->symbolic)(A, B, D, &mdata->ctx));
734:   } else { /* call general setup if symbolic operation not provided */
735:     PetscCall(MatSetUp(D));
736:   }
737:   PetscCheck(D->product, PetscObjectComm((PetscObject)D), PETSC_ERR_COR, "Product disappeared after user symbolic phase");
738:   PetscCheck(!D->product->data, PetscObjectComm((PetscObject)D), PETSC_ERR_COR, "Product data not empty after user symbolic phase");
739:   D->product->data    = mdata;
740:   D->product->destroy = MatProductCtxDestroy_MatMatShell;
741:   /* Be sure to reset these pointers if the user did something unexpected */
742:   D->ops->productsymbolic = MatProductSymbolic_Shell_X;
743:   D->ops->productnumeric  = MatProductNumeric_Shell_X;
744:   PetscFunctionReturn(PETSC_SUCCESS);
745: }

747: static PetscErrorCode MatProductSetFromOptions_Shell_X(Mat D)
748: {
749:   Mat_Product            *product;
750:   Mat                     A, B;
751:   MatShellMatFunctionList matmat;
752:   Mat_Shell              *shell;
753:   PetscBool               flg;
754:   char                    composedname[256];

756:   PetscFunctionBegin;
757:   MatCheckProduct(D, 1);
758:   product = D->product;
759:   A       = product->A;
760:   B       = product->B;
761:   PetscCall(MatIsShell(A, &flg));
762:   if (!flg) PetscFunctionReturn(PETSC_SUCCESS);
763:   shell  = (Mat_Shell *)A->data;
764:   matmat = shell->matmat;
765:   PetscCall(PetscSNPrintf(composedname, sizeof(composedname), "MatProductSetFromOptions_%s_%s_C", ((PetscObject)A)->type_name, ((PetscObject)B)->type_name));
766:   while (matmat) {
767:     PetscCall(PetscStrcmp(composedname, matmat->composedname, &flg));
768:     flg = (PetscBool)(flg && (matmat->ptype == product->type));
769:     if (flg) break;
770:     matmat = matmat->next;
771:   }
772:   if (flg) {
773:     D->ops->productsymbolic = MatProductSymbolic_Shell_X;
774:   } else PetscCall(PetscInfo(D, "  symbolic product %s not registered for product type %s\n", composedname, MatProductTypes[product->type]));
775:   PetscFunctionReturn(PETSC_SUCCESS);
776: }

778: static PetscErrorCode MatShellSetMatProductOperation_Private(Mat A, MatProductType ptype, PetscErrorCode (*symbolic)(Mat, Mat, Mat, void **), PetscErrorCode (*numeric)(Mat, Mat, Mat, void *), PetscCtxDestroyFn *destroy, char *composedname, const char *resultname)
779: {
780:   PetscBool               flg;
781:   Mat_Shell              *shell;
782:   MatShellMatFunctionList matmat;

784:   PetscFunctionBegin;
785:   PetscCheck(numeric, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Missing numeric routine");
786:   PetscCheck(composedname, PetscObjectComm((PetscObject)A), PETSC_ERR_PLIB, "Missing composed name");

788:   /* add product callback */
789:   shell  = (Mat_Shell *)A->data;
790:   matmat = shell->matmat;
791:   if (!matmat) {
792:     PetscCall(PetscNew(&shell->matmat));
793:     matmat = shell->matmat;
794:   } else {
795:     MatShellMatFunctionList entry = matmat;
796:     while (entry) {
797:       PetscCall(PetscStrcmp(composedname, entry->composedname, &flg));
798:       flg    = (PetscBool)(flg && (entry->ptype == ptype));
799:       matmat = entry;
800:       if (flg) goto set;
801:       entry = entry->next;
802:     }
803:     PetscCall(PetscNew(&matmat->next));
804:     matmat = matmat->next;
805:   }

807: set:
808:   matmat->symbolic = symbolic;
809:   matmat->numeric  = numeric;
810:   matmat->destroy  = destroy;
811:   matmat->ptype    = ptype;
812:   PetscCall(PetscFree(matmat->composedname));
813:   PetscCall(PetscFree(matmat->resultname));
814:   PetscCall(PetscStrallocpy(composedname, &matmat->composedname));
815:   PetscCall(PetscStrallocpy(resultname, &matmat->resultname));
816:   PetscCall(PetscInfo(A, "Composing %s for product type %s with result %s\n", matmat->composedname, MatProductTypes[matmat->ptype], matmat->resultname ? matmat->resultname : "not specified"));
817:   PetscCall(PetscObjectComposeFunction((PetscObject)A, matmat->composedname, MatProductSetFromOptions_Shell_X));
818:   PetscFunctionReturn(PETSC_SUCCESS);
819: }

821: /*@C
822:   MatShellSetMatProductOperation - Allows user to set a matrix matrix operation for a `MATSHELL` shell matrix.

824:   Logically Collective; No Fortran Support

826:   Input Parameters:
827: + A        - the `MATSHELL` shell matrix
828: . ptype    - the product type
829: . symbolic - the function for the symbolic phase (can be `NULL`)
830: . numeric  - the function for the numerical phase
831: . destroy  - the function for the destruction of the needed data generated during the symbolic phase (can be `NULL`)
832: . Btype    - the matrix type for the matrix to be multiplied against
833: - Ctype    - the matrix type for the result (can be `NULL`)

835:   Level: advanced

837:   Example Usage:
838: .vb
839:   extern PetscErrorCode usersymbolic(Mat, Mat, Mat, void**);
840:   extern PetscErrorCode usernumeric(Mat, Mat, Mat, void*);
841:   PetscCtxDestroyFn *ctxdestroy;

843:   MatCreateShell(comm, m, n, M, N, ctx, &A);
844:   MatShellSetMatProductOperation(
845:     A, MATPRODUCT_AB, usersymbolic, usernumeric, ctxdestroy,MATSEQAIJ, MATDENSE
846:   );
847:   // create B of type SEQAIJ etc..
848:   MatProductCreate(A, B, PETSC_NULLPTR, &C);
849:   MatProductSetType(C, MATPRODUCT_AB);
850:   MatProductSetFromOptions(C);
851:   MatProductSymbolic(C); // actually runs the user defined symbolic operation
852:   MatProductNumeric(C); // actually runs the user defined numeric operation
853:   // use C = A * B
854: .ve

856:   Notes:
857:   `MATPRODUCT_ABC` is not supported yet.

859:   If the symbolic phase is not specified, `MatSetUp()` is called on the result matrix that must have its type set if `Ctype` is `NULL`.

861:   Any additional data needed by the matrix product needs to be returned during the symbolic phase and destroyed with the destroy callback.
862:   PETSc will take care of calling the user-defined callbacks.
863:   It is allowed to specify the same callbacks for different `Btype` matrix types.
864:   The couple (`Btype`,`ptype`) uniquely identifies the operation, the last specified callbacks takes precedence.

866: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellSetContext()`, `MatSetOperation()`, `MatProductType`, `MatType`, `MatSetUp()`
867: @*/
868: PetscErrorCode MatShellSetMatProductOperation(Mat A, MatProductType ptype, PetscErrorCode (*symbolic)(Mat, Mat, Mat, void **), PetscErrorCode (*numeric)(Mat, Mat, Mat, void *), PetscCtxDestroyFn *destroy, MatType Btype, MatType Ctype)
869: {
870:   PetscFunctionBegin;
873:   PetscCheck(ptype != MATPRODUCT_ABC, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Not for product type %s", MatProductTypes[ptype]);
874:   PetscCheck(numeric, PetscObjectComm((PetscObject)A), PETSC_ERR_USER, "Missing numeric routine, argument 4");
875:   PetscAssertPointer(Btype, 6);
876:   if (Ctype) PetscAssertPointer(Ctype, 7);
877:   PetscTryMethod(A, "MatShellSetMatProductOperation_C", (Mat, MatProductType, PetscErrorCode (*)(Mat, Mat, Mat, void **), PetscErrorCode (*)(Mat, Mat, Mat, void *), PetscCtxDestroyFn *, MatType, MatType), (A, ptype, symbolic, numeric, destroy, Btype, Ctype));
878:   PetscFunctionReturn(PETSC_SUCCESS);
879: }

881: static PetscErrorCode MatShellSetMatProductOperation_Shell(Mat A, MatProductType ptype, PetscErrorCode (*symbolic)(Mat, Mat, Mat, void **), PetscErrorCode (*numeric)(Mat, Mat, Mat, void *), PetscCtxDestroyFn *destroy, MatType Btype, MatType Ctype)
882: {
883:   PetscBool   flg;
884:   char        composedname[256];
885:   MatRootName Bnames = MatRootNameList, Cnames = MatRootNameList;
886:   PetscMPIInt size;

888:   PetscFunctionBegin;
890:   while (Bnames) { /* user passed in the root name */
891:     PetscCall(PetscStrcmp(Btype, Bnames->rname, &flg));
892:     if (flg) break;
893:     Bnames = Bnames->next;
894:   }
895:   while (Cnames) { /* user passed in the root name */
896:     PetscCall(PetscStrcmp(Ctype, Cnames->rname, &flg));
897:     if (flg) break;
898:     Cnames = Cnames->next;
899:   }
900:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)A), &size));
901:   Btype = Bnames ? (size > 1 ? Bnames->mname : Bnames->sname) : Btype;
902:   Ctype = Cnames ? (size > 1 ? Cnames->mname : Cnames->sname) : Ctype;
903:   PetscCall(PetscSNPrintf(composedname, sizeof(composedname), "MatProductSetFromOptions_%s_%s_C", ((PetscObject)A)->type_name, Btype));
904:   PetscCall(MatShellSetMatProductOperation_Private(A, ptype, symbolic, numeric, destroy, composedname, Ctype));
905:   PetscFunctionReturn(PETSC_SUCCESS);
906: }

908: static PetscErrorCode MatCopy_Shell(Mat A, Mat B, MatStructure str)
909: {
910:   Mat_Shell              *shellA = (Mat_Shell *)A->data, *shellB = (Mat_Shell *)B->data;
911:   PetscBool               matflg;
912:   MatShellMatFunctionList matmatA;

914:   PetscFunctionBegin;
915:   PetscCall(MatIsShell(B, &matflg));
916:   PetscCheck(matflg, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONG, "Matrix %s not derived from MATSHELL", ((PetscObject)B)->type_name);

918:   B->ops[0]      = A->ops[0];
919:   shellB->ops[0] = shellA->ops[0];

921:   if (shellA->ops->copy) PetscCall((*shellA->ops->copy)(A, B, str));
922:   shellB->vscale = shellA->vscale;
923:   shellB->vshift = shellA->vshift;
924:   if (shellA->dshift) {
925:     if (!shellB->dshift) PetscCall(VecDuplicate(shellA->dshift, &shellB->dshift));
926:     PetscCall(VecCopy(shellA->dshift, shellB->dshift));
927:   } else {
928:     PetscCall(VecDestroy(&shellB->dshift));
929:   }
930:   if (shellA->left) {
931:     if (!shellB->left) PetscCall(VecDuplicate(shellA->left, &shellB->left));
932:     PetscCall(VecCopy(shellA->left, shellB->left));
933:   } else {
934:     PetscCall(VecDestroy(&shellB->left));
935:   }
936:   if (shellA->right) {
937:     if (!shellB->right) PetscCall(VecDuplicate(shellA->right, &shellB->right));
938:     PetscCall(VecCopy(shellA->right, shellB->right));
939:   } else {
940:     PetscCall(VecDestroy(&shellB->right));
941:   }
942:   PetscCall(MatDestroy(&shellB->axpy));
943:   shellB->axpy_vscale = 0.0;
944:   shellB->axpy_state  = 0;
945:   if (shellA->axpy) {
946:     PetscCall(PetscObjectReference((PetscObject)shellA->axpy));
947:     shellB->axpy        = shellA->axpy;
948:     shellB->axpy_vscale = shellA->axpy_vscale;
949:     shellB->axpy_state  = shellA->axpy_state;
950:   }
951:   if (shellA->zrows) {
952:     PetscCall(ISDuplicate(shellA->zrows, &shellB->zrows));
953:     if (shellA->zcols) PetscCall(ISDuplicate(shellA->zcols, &shellB->zcols));
954:     PetscCall(VecDuplicate(shellA->zvals, &shellB->zvals));
955:     PetscCall(VecCopy(shellA->zvals, shellB->zvals));
956:     PetscCall(VecDuplicate(shellA->zvals_w, &shellB->zvals_w));
957:     PetscCall(PetscObjectReference((PetscObject)shellA->zvals_sct_r));
958:     PetscCall(PetscObjectReference((PetscObject)shellA->zvals_sct_c));
959:     shellB->zvals_sct_r = shellA->zvals_sct_r;
960:     shellB->zvals_sct_c = shellA->zvals_sct_c;
961:   }

963:   matmatA = shellA->matmat;
964:   if (matmatA) {
965:     while (matmatA->next) {
966:       PetscCall(MatShellSetMatProductOperation_Private(B, matmatA->ptype, matmatA->symbolic, matmatA->numeric, matmatA->destroy, matmatA->composedname, matmatA->resultname));
967:       matmatA = matmatA->next;
968:     }
969:   }
970:   PetscFunctionReturn(PETSC_SUCCESS);
971: }

973: static PetscErrorCode MatDuplicate_Shell(Mat mat, MatDuplicateOption op, Mat *M)
974: {
975:   PetscFunctionBegin;
976:   PetscCall(MatCreateShell(PetscObjectComm((PetscObject)mat), mat->rmap->n, mat->cmap->n, mat->rmap->N, mat->cmap->N, NULL, M));
977:   ((Mat_Shell *)(*M)->data)->ctxcontainer = ((Mat_Shell *)mat->data)->ctxcontainer;
978:   PetscCall(PetscObjectCompose((PetscObject)*M, "MatShell ctx", (PetscObject)((Mat_Shell *)(*M)->data)->ctxcontainer));
979:   PetscCall(PetscObjectChangeTypeName((PetscObject)*M, ((PetscObject)mat)->type_name));
980:   if (op == MAT_COPY_VALUES) PetscCall(MatCopy(mat, *M, SAME_NONZERO_PATTERN));
981:   PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)mat, (PetscObject)*M));
982:   PetscFunctionReturn(PETSC_SUCCESS);
983: }

985: static PetscErrorCode MatMult_Shell(Mat A, Vec x, Vec y)
986: {
987:   Mat_Shell       *shell = (Mat_Shell *)A->data;
988:   Vec              xx;
989:   PetscObjectState instate, outstate;

991:   PetscFunctionBegin;
992:   PetscCall(MatShellPreZeroRight(A, x, &xx));
993:   PetscCall(MatShellPreScaleRight(A, xx, &xx));
994:   PetscCall(PetscObjectStateGet((PetscObject)y, &instate));
995:   PetscCall((*shell->ops->mult)(A, xx, y));
996:   PetscCall(PetscObjectStateGet((PetscObject)y, &outstate));
997:   if (instate == outstate) {
998:     /* increase the state of the output vector since the user did not update its state themself as should have been done */
999:     PetscCall(PetscObjectStateIncrease((PetscObject)y));
1000:   }
1001:   PetscCall(MatShellShiftAndScale(A, xx, y, PETSC_FALSE));
1002:   PetscCall(MatShellPostScaleLeft(A, y));
1003:   PetscCall(MatShellPostZeroLeft(A, y));

1005:   if (shell->axpy) {
1006:     Mat              X;
1007:     PetscObjectState axpy_state;

1009:     PetscCall(MatShellGetContext(shell->axpy, &X));
1010:     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1011:     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");

1013:     PetscCall(MatCreateVecs(shell->axpy, shell->axpy_right ? NULL : &shell->axpy_right, shell->axpy_left ? NULL : &shell->axpy_left));
1014:     PetscCall(VecCopy(x, shell->axpy_right));
1015:     PetscCall(MatMult(shell->axpy, shell->axpy_right, shell->axpy_left));
1016:     PetscCall(VecAXPY(y, shell->axpy_vscale, shell->axpy_left));
1017:   }
1018:   PetscFunctionReturn(PETSC_SUCCESS);
1019: }

1021: static PetscErrorCode MatMultAdd_Shell(Mat A, Vec x, Vec y, Vec z)
1022: {
1023:   Mat_Shell *shell = (Mat_Shell *)A->data;

1025:   PetscFunctionBegin;
1026:   if (y == z) {
1027:     if (!shell->right_add_work) PetscCall(VecDuplicate(z, &shell->right_add_work));
1028:     PetscCall(MatMult(A, x, shell->right_add_work));
1029:     PetscCall(VecAXPY(z, 1.0, shell->right_add_work));
1030:   } else {
1031:     PetscCall(MatMult(A, x, z));
1032:     PetscCall(VecAXPY(z, 1.0, y));
1033:   }
1034:   PetscFunctionReturn(PETSC_SUCCESS);
1035: }

1037: static PetscErrorCode MatMultTranspose_Shell(Mat A, Vec x, Vec y)
1038: {
1039:   Mat_Shell       *shell = (Mat_Shell *)A->data;
1040:   Vec              xx;
1041:   PetscObjectState instate, outstate;

1043:   PetscFunctionBegin;
1044:   PetscCall(MatShellPreZeroLeft(A, x, &xx));
1045:   PetscCall(MatShellPreScaleLeft(A, xx, &xx, PETSC_FALSE));
1046:   PetscCall(PetscObjectStateGet((PetscObject)y, &instate));
1047:   PetscCall((*shell->ops->multtranspose)(A, xx, y));
1048:   PetscCall(PetscObjectStateGet((PetscObject)y, &outstate));
1049:   if (instate == outstate) {
1050:     /* increase the state of the output vector since the user did not update its state themself as should have been done */
1051:     PetscCall(PetscObjectStateIncrease((PetscObject)y));
1052:   }
1053:   PetscCall(MatShellShiftAndScale(A, xx, y, PETSC_FALSE));
1054:   PetscCall(MatShellPostScaleRight(A, y, PETSC_FALSE));
1055:   PetscCall(MatShellPostZeroRight(A, y));

1057:   if (shell->axpy) {
1058:     Mat              X;
1059:     PetscObjectState axpy_state;

1061:     PetscCall(MatShellGetContext(shell->axpy, &X));
1062:     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1063:     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
1064:     PetscCall(MatCreateVecs(shell->axpy, shell->axpy_right ? NULL : &shell->axpy_right, shell->axpy_left ? NULL : &shell->axpy_left));
1065:     PetscCall(VecCopy(x, shell->axpy_left));
1066:     PetscCall(MatMultTranspose(shell->axpy, shell->axpy_left, shell->axpy_right));
1067:     PetscCall(VecAXPY(y, shell->axpy_vscale, shell->axpy_right));
1068:   }
1069:   PetscFunctionReturn(PETSC_SUCCESS);
1070: }

1072: static PetscErrorCode MatMultHermitianTranspose_Shell(Mat A, Vec x, Vec y)
1073: {
1074:   Mat_Shell       *shell = (Mat_Shell *)A->data;
1075:   Vec              xx;
1076:   PetscObjectState instate, outstate;

1078:   PetscFunctionBegin;
1079:   PetscCall(MatShellPreZeroLeft(A, x, &xx));
1080:   PetscCall(MatShellPreScaleLeft(A, xx, &xx, PETSC_TRUE));
1081:   PetscCall(PetscObjectStateGet((PetscObject)y, &instate));
1082:   PetscCall((*shell->ops->multhermitiantranspose)(A, xx, y));
1083:   PetscCall(PetscObjectStateGet((PetscObject)y, &outstate));
1084:   if (instate == outstate) {
1085:     /* increase the state of the output vector since the user did not update its state themself as should have been done */
1086:     PetscCall(PetscObjectStateIncrease((PetscObject)y));
1087:   }
1088:   PetscCall(MatShellShiftAndScale(A, xx, y, PETSC_TRUE));
1089:   PetscCall(MatShellPostScaleRight(A, y, PETSC_TRUE));
1090:   PetscCall(MatShellPostZeroRight(A, y));

1092:   if (shell->axpy) {
1093:     Mat              X;
1094:     PetscObjectState axpy_state;

1096:     PetscCall(MatShellGetContext(shell->axpy, &X));
1097:     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1098:     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
1099:     PetscCall(MatCreateVecs(shell->axpy, shell->axpy_right ? NULL : &shell->axpy_right, shell->axpy_left ? NULL : &shell->axpy_left));
1100:     PetscCall(VecCopy(x, shell->axpy_left));
1101:     PetscCall(MatMultHermitianTranspose(shell->axpy, shell->axpy_left, shell->axpy_right));
1102:     PetscCall(VecAXPY(y, PetscConj(shell->axpy_vscale), shell->axpy_right));
1103:   }
1104:   PetscFunctionReturn(PETSC_SUCCESS);
1105: }

1107: static PetscErrorCode MatMultTransposeAdd_Shell(Mat A, Vec x, Vec y, Vec z)
1108: {
1109:   Mat_Shell *shell = (Mat_Shell *)A->data;

1111:   PetscFunctionBegin;
1112:   if (y == z) {
1113:     if (!shell->left_add_work) PetscCall(VecDuplicate(z, &shell->left_add_work));
1114:     PetscCall(MatMultTranspose(A, x, shell->left_add_work));
1115:     PetscCall(VecAXPY(z, 1.0, shell->left_add_work));
1116:   } else {
1117:     PetscCall(MatMultTranspose(A, x, z));
1118:     PetscCall(VecAXPY(z, 1.0, y));
1119:   }
1120:   PetscFunctionReturn(PETSC_SUCCESS);
1121: }

1123: static PetscErrorCode MatMultHermitianTransposeAdd_Shell(Mat A, Vec x, Vec y, Vec z)
1124: {
1125:   Mat_Shell *shell = (Mat_Shell *)A->data;

1127:   PetscFunctionBegin;
1128:   if (y == z) {
1129:     if (!shell->left_add_work) PetscCall(VecDuplicate(z, &shell->left_add_work));
1130:     PetscCall(MatMultHermitianTranspose(A, x, shell->left_add_work));
1131:     PetscCall(VecAXPY(z, 1.0, shell->left_add_work));
1132:   } else {
1133:     PetscCall(MatMultHermitianTranspose(A, x, z));
1134:     PetscCall(VecAXPY(z, 1.0, y));
1135:   }
1136:   PetscFunctionReturn(PETSC_SUCCESS);
1137: }

1139: /*
1140:           diag(left)(vscale*A + diag(dshift) + vshift I)diag(right)
1141: */
1142: static PetscErrorCode MatGetDiagonal_Shell(Mat A, Vec v)
1143: {
1144:   Mat_Shell *shell = (Mat_Shell *)A->data;

1146:   PetscFunctionBegin;
1147:   PetscCheck(shell->ops->getdiagonal, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Must provide shell matrix with routine to return diagonal using MatShellSetOperation(S, MATOP_GET_DIAGONAL...)");
1148:   PetscCall((*shell->ops->getdiagonal)(A, v));
1149:   PetscCall(VecScale(v, shell->vscale));
1150:   if (shell->dshift) PetscCall(VecAXPY(v, 1.0, shell->dshift));
1151:   PetscCall(VecShift(v, shell->vshift));
1152:   if (shell->left) PetscCall(VecPointwiseMult(v, v, shell->left));
1153:   if (shell->right) PetscCall(VecPointwiseMult(v, v, shell->right));
1154:   if (shell->zrows) {
1155:     PetscCall(VecScatterBegin(shell->zvals_sct_r, shell->zvals, v, INSERT_VALUES, SCATTER_REVERSE));
1156:     PetscCall(VecScatterEnd(shell->zvals_sct_r, shell->zvals, v, INSERT_VALUES, SCATTER_REVERSE));
1157:   }
1158:   if (shell->axpy) {
1159:     Mat              X;
1160:     PetscObjectState axpy_state;

1162:     PetscCall(MatShellGetContext(shell->axpy, &X));
1163:     PetscCall(PetscObjectStateGet((PetscObject)X, &axpy_state));
1164:     PetscCheck(shell->axpy_state == axpy_state, PetscObjectComm((PetscObject)A), PETSC_ERR_ORDER, "Invalid AXPY state: cannot modify the X matrix passed to MatAXPY(Y,a,X,...)");
1165:     PetscCall(MatCreateVecs(shell->axpy, NULL, shell->axpy_left ? NULL : &shell->axpy_left));
1166:     PetscCall(MatGetDiagonal(shell->axpy, shell->axpy_left));
1167:     PetscCall(VecAXPY(v, shell->axpy_vscale, shell->axpy_left));
1168:   }
1169:   PetscFunctionReturn(PETSC_SUCCESS);
1170: }

1172: static PetscErrorCode MatGetDiagonalBlock_Shell(Mat A, Mat *b)
1173: {
1174:   Mat_Shell *shell = (Mat_Shell *)A->data;
1175:   Vec        left = NULL, right = NULL;

1177:   PetscFunctionBegin;
1178:   PetscCheck(!shell->zrows && !shell->zcols, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot call MatGetDiagonalBlock() if MatZeroRows() or MatZeroRowsColumns() has been called on the input Mat"); // TODO FIXME
1179:   PetscCheck(!shell->axpy, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot call MatGetDiagonalBlock() if MatAXPY() has been called on the input Mat");                                               // TODO FIXME
1180:   PetscCheck(!shell->dshift, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot call MatGetDiagonalBlock() if MatDiagonalSet() has been called on the input Mat");                                      // TODO FIXME
1181:   PetscCheck(shell->ops->getdiagonalblock, PetscObjectComm((PetscObject)A), PETSC_ERR_ARG_WRONGSTATE, "Must provide shell matrix with routine to return diagonal block using MatShellSetOperation(S, MATOP_GET_DIAGONAL_BLOCK...)");
1182:   PetscCall((*shell->ops->getdiagonalblock)(A, b));
1183:   PetscCall(MatScale(*b, shell->vscale));
1184:   PetscCall(MatShift(*b, shell->vshift));
1185:   if (shell->left) {
1186:     PetscCall(VecCreateLocalVector(shell->left, &left));
1187:     PetscCall(VecGetLocalVectorRead(shell->left, left));
1188:   }
1189:   if (shell->right) {
1190:     PetscCall(VecCreateLocalVector(shell->right, &right));
1191:     PetscCall(VecGetLocalVectorRead(shell->right, right));
1192:   }
1193:   PetscCall(MatDiagonalScale(*b, left, right));
1194:   if (shell->left) {
1195:     PetscCall(VecRestoreLocalVectorRead(shell->left, left));
1196:     PetscCall(VecDestroy(&left));
1197:   }
1198:   if (shell->right) {
1199:     PetscCall(VecRestoreLocalVectorRead(shell->right, right));
1200:     PetscCall(VecDestroy(&right));
1201:   }
1202:   PetscFunctionReturn(PETSC_SUCCESS);
1203: }

1205: static PetscErrorCode MatShift_Shell(Mat Y, PetscScalar a)
1206: {
1207:   Mat_Shell *shell = (Mat_Shell *)Y->data;
1208:   PetscBool  flg;

1210:   PetscFunctionBegin;
1211:   PetscCall(MatHasCongruentLayouts(Y, &flg));
1212:   PetscCheck(flg, PetscObjectComm((PetscObject)Y), PETSC_ERR_SUP, "Cannot shift shell matrix if it is not congruent");
1213:   if (shell->left || shell->right) {
1214:     if (!shell->dshift) {
1215:       PetscCall(VecDuplicate(shell->left ? shell->left : shell->right, &shell->dshift));
1216:       PetscCall(VecSet(shell->dshift, a));
1217:     } else {
1218:       if (shell->left) PetscCall(VecPointwiseMult(shell->dshift, shell->dshift, shell->left));
1219:       if (shell->right) PetscCall(VecPointwiseMult(shell->dshift, shell->dshift, shell->right));
1220:       PetscCall(VecShift(shell->dshift, a));
1221:     }
1222:     if (shell->left) PetscCall(VecPointwiseDivide(shell->dshift, shell->dshift, shell->left));
1223:     if (shell->right) PetscCall(VecPointwiseDivide(shell->dshift, shell->dshift, shell->right));
1224:   } else shell->vshift += a;
1225:   if (shell->zrows) PetscCall(VecShift(shell->zvals, a));
1226:   PetscFunctionReturn(PETSC_SUCCESS);
1227: }

1229: static PetscErrorCode MatDiagonalSet_Shell_Private(Mat A, Vec D, PetscScalar s)
1230: {
1231:   Mat_Shell *shell = (Mat_Shell *)A->data;

1233:   PetscFunctionBegin;
1234:   if (!shell->dshift) PetscCall(VecDuplicate(D, &shell->dshift));
1235:   if (shell->left || shell->right) {
1236:     if (!shell->right_work) PetscCall(VecDuplicate(shell->left ? shell->left : shell->right, &shell->right_work));
1237:     if (shell->left && shell->right) {
1238:       PetscCall(VecPointwiseDivide(shell->right_work, D, shell->left));
1239:       PetscCall(VecPointwiseDivide(shell->right_work, shell->right_work, shell->right));
1240:     } else if (shell->left) {
1241:       PetscCall(VecPointwiseDivide(shell->right_work, D, shell->left));
1242:     } else {
1243:       PetscCall(VecPointwiseDivide(shell->right_work, D, shell->right));
1244:     }
1245:     PetscCall(VecAXPY(shell->dshift, s, shell->right_work));
1246:   } else {
1247:     PetscCall(VecAXPY(shell->dshift, s, D));
1248:   }
1249:   PetscFunctionReturn(PETSC_SUCCESS);
1250: }

1252: static PetscErrorCode MatDiagonalSet_Shell(Mat A, Vec D, InsertMode ins)
1253: {
1254:   Mat_Shell *shell = (Mat_Shell *)A->data;
1255:   Vec        d;
1256:   PetscBool  flg;

1258:   PetscFunctionBegin;
1259:   PetscCall(MatHasCongruentLayouts(A, &flg));
1260:   PetscCheck(flg, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot diagonal set or shift shell matrix if it is not congruent");
1261:   if (ins == INSERT_VALUES) {
1262:     PetscCall(VecDuplicate(D, &d));
1263:     PetscCall(MatGetDiagonal(A, d));
1264:     PetscCall(MatDiagonalSet_Shell_Private(A, d, -1.));
1265:     PetscCall(MatDiagonalSet_Shell_Private(A, D, 1.));
1266:     PetscCall(VecDestroy(&d));
1267:     if (shell->zrows) PetscCall(VecCopy(D, shell->zvals));
1268:   } else {
1269:     PetscCall(MatDiagonalSet_Shell_Private(A, D, 1.));
1270:     if (shell->zrows) PetscCall(VecAXPY(shell->zvals, 1.0, D));
1271:   }
1272:   PetscFunctionReturn(PETSC_SUCCESS);
1273: }

1275: static PetscErrorCode MatScale_Shell(Mat Y, PetscScalar a)
1276: {
1277:   Mat_Shell *shell = (Mat_Shell *)Y->data;

1279:   PetscFunctionBegin;
1280:   shell->vscale *= a;
1281:   shell->vshift *= a;
1282:   if (shell->dshift) PetscCall(VecScale(shell->dshift, a));
1283:   shell->axpy_vscale *= a;
1284:   if (shell->zrows) PetscCall(VecScale(shell->zvals, a));
1285:   PetscFunctionReturn(PETSC_SUCCESS);
1286: }

1288: static PetscErrorCode MatDiagonalScale_Shell(Mat Y, Vec left, Vec right)
1289: {
1290:   Mat_Shell *shell = (Mat_Shell *)Y->data;

1292:   PetscFunctionBegin;
1293:   if (left) {
1294:     if (!shell->left) {
1295:       PetscCall(VecDuplicate(left, &shell->left));
1296:       PetscCall(VecCopy(left, shell->left));
1297:     } else {
1298:       PetscCall(VecPointwiseMult(shell->left, shell->left, left));
1299:     }
1300:     if (shell->zrows) PetscCall(VecPointwiseMult(shell->zvals, shell->zvals, left));
1301:   }
1302:   if (right) {
1303:     if (!shell->right) {
1304:       PetscCall(VecDuplicate(right, &shell->right));
1305:       PetscCall(VecCopy(right, shell->right));
1306:     } else {
1307:       PetscCall(VecPointwiseMult(shell->right, shell->right, right));
1308:     }
1309:     if (shell->zrows) {
1310:       if (!shell->left_work) PetscCall(MatCreateVecs(Y, NULL, &shell->left_work));
1311:       PetscCall(VecSet(shell->zvals_w, 1.0));
1312:       PetscCall(VecScatterBegin(shell->zvals_sct_c, right, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
1313:       PetscCall(VecScatterEnd(shell->zvals_sct_c, right, shell->zvals_w, INSERT_VALUES, SCATTER_FORWARD));
1314:       PetscCall(VecPointwiseMult(shell->zvals, shell->zvals, shell->zvals_w));
1315:     }
1316:   }
1317:   if (shell->axpy) PetscCall(MatDiagonalScale(shell->axpy, left, right));
1318:   PetscFunctionReturn(PETSC_SUCCESS);
1319: }

1321: PETSC_INTERN PetscErrorCode MatAssemblyEnd_Shell(Mat Y, MatAssemblyType t)
1322: {
1323:   Mat_Shell *shell = (Mat_Shell *)Y->data;

1325:   PetscFunctionBegin;
1326:   if (t == MAT_FINAL_ASSEMBLY) {
1327:     shell->vshift      = 0.0;
1328:     shell->vscale      = 1.0;
1329:     shell->axpy_vscale = 0.0;
1330:     shell->axpy_state  = 0;
1331:     PetscCall(VecDestroy(&shell->dshift));
1332:     PetscCall(VecDestroy(&shell->left));
1333:     PetscCall(VecDestroy(&shell->right));
1334:     PetscCall(MatDestroy(&shell->axpy));
1335:     PetscCall(VecDestroy(&shell->axpy_left));
1336:     PetscCall(VecDestroy(&shell->axpy_right));
1337:     PetscCall(VecScatterDestroy(&shell->zvals_sct_c));
1338:     PetscCall(VecScatterDestroy(&shell->zvals_sct_r));
1339:     PetscCall(ISDestroy(&shell->zrows));
1340:     PetscCall(ISDestroy(&shell->zcols));
1341:   }
1342:   PetscFunctionReturn(PETSC_SUCCESS);
1343: }

1345: static PetscErrorCode MatAXPY_Shell(Mat Y, PetscScalar a, Mat X, MatStructure str)
1346: {
1347:   Mat_Shell *shell = (Mat_Shell *)Y->data;

1349:   PetscFunctionBegin;
1350:   if (X == Y) {
1351:     PetscCall(MatScale(Y, 1.0 + a));
1352:     PetscFunctionReturn(PETSC_SUCCESS);
1353:   }
1354:   if (!shell->axpy) {
1355:     PetscCall(MatConvertFrom_Shell(X, MATSHELL, MAT_INITIAL_MATRIX, &shell->axpy));
1356:     shell->axpy_vscale = a;
1357:     PetscCall(PetscObjectStateGet((PetscObject)X, &shell->axpy_state));
1358:   } else {
1359:     PetscCall(MatAXPY(shell->axpy, a / shell->axpy_vscale, X, str));
1360:   }
1361:   PetscFunctionReturn(PETSC_SUCCESS);
1362: }

1364: static struct _MatOps MatOps_Values = {NULL,
1365:                                        NULL,
1366:                                        NULL,
1367:                                        NULL,
1368:                                        /* 4*/ MatMultAdd_Shell,
1369:                                        NULL,
1370:                                        MatMultTransposeAdd_Shell,
1371:                                        NULL,
1372:                                        NULL,
1373:                                        NULL,
1374:                                        /*10*/ NULL,
1375:                                        NULL,
1376:                                        NULL,
1377:                                        NULL,
1378:                                        NULL,
1379:                                        /*15*/ NULL,
1380:                                        NULL,
1381:                                        NULL,
1382:                                        MatDiagonalScale_Shell,
1383:                                        NULL,
1384:                                        /*20*/ NULL,
1385:                                        MatAssemblyEnd_Shell,
1386:                                        NULL,
1387:                                        NULL,
1388:                                        /*24*/ MatZeroRows_Shell,
1389:                                        NULL,
1390:                                        NULL,
1391:                                        NULL,
1392:                                        NULL,
1393:                                        /*29*/ NULL,
1394:                                        NULL,
1395:                                        NULL,
1396:                                        /*32*/ NULL,
1397:                                        NULL,
1398:                                        /*34*/ MatDuplicate_Shell,
1399:                                        NULL,
1400:                                        NULL,
1401:                                        NULL,
1402:                                        NULL,
1403:                                        /*39*/ MatAXPY_Shell,
1404:                                        NULL,
1405:                                        NULL,
1406:                                        NULL,
1407:                                        MatCopy_Shell,
1408:                                        /*44*/ NULL,
1409:                                        MatScale_Shell,
1410:                                        MatShift_Shell,
1411:                                        MatDiagonalSet_Shell,
1412:                                        MatZeroRowsColumns_Shell,
1413:                                        /*49*/ NULL,
1414:                                        NULL,
1415:                                        NULL,
1416:                                        NULL,
1417:                                        NULL,
1418:                                        /*54*/ NULL,
1419:                                        NULL,
1420:                                        NULL,
1421:                                        NULL,
1422:                                        NULL,
1423:                                        /*59*/ NULL,
1424:                                        MatDestroy_Shell,
1425:                                        NULL,
1426:                                        MatConvertFrom_Shell,
1427:                                        NULL,
1428:                                        /*64*/ NULL,
1429:                                        NULL,
1430:                                        NULL,
1431:                                        NULL,
1432:                                        NULL,
1433:                                        /*69*/ NULL,
1434:                                        MatConvert_Shell,
1435:                                        NULL,
1436:                                        NULL,
1437:                                        NULL,
1438:                                        /*74*/ NULL,
1439:                                        NULL,
1440:                                        NULL,
1441:                                        NULL,
1442:                                        NULL,
1443:                                        /*79*/ NULL,
1444:                                        NULL,
1445:                                        NULL,
1446:                                        NULL,
1447:                                        NULL,
1448:                                        /*84*/ NULL,
1449:                                        NULL,
1450:                                        NULL,
1451:                                        NULL,
1452:                                        NULL,
1453:                                        /*89*/ NULL,
1454:                                        NULL,
1455:                                        NULL,
1456:                                        NULL,
1457:                                        NULL,
1458:                                        /*94*/ NULL,
1459:                                        NULL,
1460:                                        NULL,
1461:                                        NULL,
1462:                                        NULL,
1463:                                        /*99*/ NULL,
1464:                                        NULL,
1465:                                        NULL,
1466:                                        NULL,
1467:                                        NULL,
1468:                                        /*104*/ NULL,
1469:                                        NULL,
1470:                                        NULL,
1471:                                        NULL,
1472:                                        NULL,
1473:                                        /*109*/ NULL,
1474:                                        NULL,
1475:                                        NULL,
1476:                                        MatMultHermitianTransposeAdd_Shell,
1477:                                        NULL,
1478:                                        /*114*/ NULL,
1479:                                        NULL,
1480:                                        NULL,
1481:                                        NULL,
1482:                                        NULL,
1483:                                        /*119*/ NULL,
1484:                                        NULL,
1485:                                        NULL,
1486:                                        NULL,
1487:                                        NULL,
1488:                                        /*124*/ NULL,
1489:                                        NULL,
1490:                                        NULL,
1491:                                        NULL,
1492:                                        NULL,
1493:                                        /*129*/ NULL,
1494:                                        NULL,
1495:                                        NULL,
1496:                                        NULL,
1497:                                        NULL,
1498:                                        /*134*/ NULL,
1499:                                        NULL,
1500:                                        NULL,
1501:                                        NULL,
1502:                                        NULL,
1503:                                        /*139*/ NULL,
1504:                                        NULL,
1505:                                        NULL,
1506:                                        NULL,
1507:                                        NULL};

1509: static PetscErrorCode MatShellSetContext_Shell(Mat mat, PetscCtx ctx)
1510: {
1511:   Mat_Shell *shell = (Mat_Shell *)mat->data;

1513:   PetscFunctionBegin;
1514:   if (ctx) {
1515:     PetscContainer ctxcontainer;
1516:     PetscCall(PetscContainerCreate(PetscObjectComm((PetscObject)mat), &ctxcontainer));
1517:     PetscCall(PetscContainerSetPointer(ctxcontainer, ctx));
1518:     PetscCall(PetscObjectCompose((PetscObject)mat, "MatShell ctx", (PetscObject)ctxcontainer));
1519:     shell->ctxcontainer = ctxcontainer;
1520:     PetscCall(PetscContainerDestroy(&ctxcontainer));
1521:   } else {
1522:     PetscCall(PetscObjectCompose((PetscObject)mat, "MatShell ctx", NULL));
1523:     shell->ctxcontainer = NULL;
1524:   }
1525:   PetscFunctionReturn(PETSC_SUCCESS);
1526: }

1528: static PetscErrorCode MatShellSetContextDestroy_Shell(Mat mat, PetscCtxDestroyFn *f)
1529: {
1530:   Mat_Shell *shell = (Mat_Shell *)mat->data;

1532:   PetscFunctionBegin;
1533:   if (shell->ctxcontainer) PetscCall(PetscContainerSetCtxDestroy(shell->ctxcontainer, f));
1534:   PetscFunctionReturn(PETSC_SUCCESS);
1535: }

1537: PetscErrorCode MatShellSetContext_Immutable(Mat mat, PetscCtx ctx)
1538: {
1539:   PetscFunctionBegin;
1540:   SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot call MatShellSetContext() for a %s, it is used internally by the structure", ((PetscObject)mat)->type_name);
1541:   PetscFunctionReturn(PETSC_SUCCESS);
1542: }

1544: PetscErrorCode MatShellSetContextDestroy_Immutable(Mat mat, PetscCtxDestroyFn *f)
1545: {
1546:   PetscFunctionBegin;
1547:   SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot call MatShellSetContextDestroy() for a %s, it is used internally by the structure", ((PetscObject)mat)->type_name);
1548:   PetscFunctionReturn(PETSC_SUCCESS);
1549: }

1551: PetscErrorCode MatShellSetManageScalingShifts_Immutable(Mat mat)
1552: {
1553:   PetscFunctionBegin;
1554:   SETERRQ(PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "Cannot call MatShellSetManageScalingShifts() for a %s, it is used internally by the structure", ((PetscObject)mat)->type_name);
1555:   PetscFunctionReturn(PETSC_SUCCESS);
1556: }

1558: static PetscErrorCode MatShellSetVecType_Shell(Mat mat, VecType vtype)
1559: {
1560:   PetscFunctionBegin;
1561:   PetscCall(PetscFree(mat->defaultvectype));
1562:   PetscCall(PetscStrallocpy(vtype, (char **)&mat->defaultvectype));
1563:   PetscFunctionReturn(PETSC_SUCCESS);
1564: }

1566: static PetscErrorCode MatShellSetManageScalingShifts_Shell(Mat A)
1567: {
1568:   Mat_Shell *shell = (Mat_Shell *)A->data;

1570:   PetscFunctionBegin;
1571:   shell->managescalingshifts = PETSC_FALSE;
1572:   A->ops->diagonalset        = NULL;
1573:   A->ops->diagonalscale      = NULL;
1574:   A->ops->scale              = NULL;
1575:   A->ops->shift              = NULL;
1576:   A->ops->axpy               = NULL;
1577:   PetscFunctionReturn(PETSC_SUCCESS);
1578: }

1580: static PetscErrorCode MatShellGetScalingShifts_Shell(Mat A, PetscScalar *vshift, PetscScalar *vscale, Vec *dshift, Vec *left, Vec *right, Mat *axpy, IS *zrows, IS *zcols)
1581: {
1582:   Mat_Shell *shell = (Mat_Shell *)A->data;

1584:   PetscFunctionBegin;
1585:   PetscCheck(shell->managescalingshifts, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Cannot get scaling and shifts if MatShellSetManageScalingShifts() has been called");
1586:   if (vshift == MAT_SHELL_NOT_ALLOWED) PetscCheck(shell->vshift == 0.0, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: vshift != 0.0, set via MatShift()");
1587:   else if (vshift) *vshift = shell->vshift;
1588:   if (vscale == MAT_SHELL_NOT_ALLOWED) PetscCheck(shell->vscale == 1.0, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: vscale != 1.0, set via MatScale()");
1589:   else if (vscale) *vscale = shell->vscale;
1590:   if (dshift == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->dshift, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: dshift, set via MatDiagonalSet()");
1591:   else if (dshift) *dshift = shell->dshift;
1592:   if (left == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->left, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: left, set via MatDiagonalScale()");
1593:   else if (left) *left = shell->left;
1594:   if (right == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->right, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: right, set via MatDiagonalScale()");
1595:   else if (right) *right = shell->right;
1596:   if (axpy == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->axpy, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: axpy, set via MatAXPY()");
1597:   else if (axpy) *axpy = shell->axpy;
1598:   if (zrows == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->zrows, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: zrows, set via MatZeroRows()");
1599:   else if (zrows) *zrows = shell->zrows;
1600:   if (zcols == MAT_SHELL_NOT_ALLOWED) PetscCheck(!shell->zcols, PetscObjectComm((PetscObject)A), PETSC_ERR_SUP, "Non-trivial member in parent MatShell: zcols, set via MatZeroRowsColumns()");
1601:   else if (zcols) *zcols = shell->zcols;
1602:   PetscFunctionReturn(PETSC_SUCCESS);
1603: }

1605: static PetscErrorCode MatShellSetOperation_Shell(Mat mat, MatOperation op, PetscErrorCodeFn *f)
1606: {
1607:   Mat_Shell *shell = (Mat_Shell *)mat->data;

1609:   PetscFunctionBegin;
1610:   switch (op) {
1611:   case MATOP_DESTROY:
1612:     shell->ops->destroy = (PetscErrorCode (*)(Mat))f;
1613:     break;
1614:   case MATOP_VIEW:
1615:     if (!mat->ops->viewnative) mat->ops->viewnative = mat->ops->view;
1616:     mat->ops->view = (PetscErrorCode (*)(Mat, PetscViewer))f;
1617:     break;
1618:   case MATOP_COPY:
1619:     shell->ops->copy = (PetscErrorCode (*)(Mat, Mat, MatStructure))f;
1620:     break;
1621:   case MATOP_DIAGONAL_SET:
1622:   case MATOP_DIAGONAL_SCALE:
1623:   case MATOP_SHIFT:
1624:   case MATOP_SCALE:
1625:   case MATOP_AXPY:
1626:   case MATOP_ZERO_ROWS:
1627:   case MATOP_ZERO_ROWS_COLUMNS:
1628:   case MATOP_ZERO_ROWS_LOCAL:
1629:   case MATOP_ZERO_ROWS_COLUMNS_LOCAL:
1630:     PetscCheck(!shell->managescalingshifts, PetscObjectComm((PetscObject)mat), PETSC_ERR_ARG_WRONGSTATE, "MATSHELL is managing scalings and shifts, see MatShellSetManageScalingShifts()");
1631:     (((PetscErrorCodeFn **)mat->ops)[op]) = f;
1632:     break;
1633:   case MATOP_GET_DIAGONAL:
1634:     if (shell->managescalingshifts) {
1635:       shell->ops->getdiagonal = (PetscErrorCode (*)(Mat, Vec))f;
1636:       mat->ops->getdiagonal   = MatGetDiagonal_Shell;
1637:     } else {
1638:       shell->ops->getdiagonal = NULL;
1639:       mat->ops->getdiagonal   = (PetscErrorCode (*)(Mat, Vec))f;
1640:     }
1641:     break;
1642:   case MATOP_GET_DIAGONAL_BLOCK:
1643:     if (shell->managescalingshifts) {
1644:       shell->ops->getdiagonalblock = (PetscErrorCode (*)(Mat, Mat *))f;
1645:       mat->ops->getdiagonalblock   = MatGetDiagonalBlock_Shell;
1646:     } else {
1647:       shell->ops->getdiagonalblock = NULL;
1648:       mat->ops->getdiagonalblock   = (PetscErrorCode (*)(Mat, Mat *))f;
1649:     }
1650:     break;
1651:   case MATOP_MULT:
1652:     if (shell->managescalingshifts) {
1653:       shell->ops->mult = (PetscErrorCode (*)(Mat, Vec, Vec))f;
1654:       mat->ops->mult   = MatMult_Shell;
1655:     } else {
1656:       shell->ops->mult = NULL;
1657:       mat->ops->mult   = (PetscErrorCode (*)(Mat, Vec, Vec))f;
1658:     }
1659:     break;
1660:   case MATOP_MULT_TRANSPOSE:
1661:     if (shell->managescalingshifts) {
1662:       shell->ops->multtranspose = (PetscErrorCode (*)(Mat, Vec, Vec))f;
1663:       mat->ops->multtranspose   = MatMultTranspose_Shell;
1664:     } else {
1665:       shell->ops->multtranspose = NULL;
1666:       mat->ops->multtranspose   = (PetscErrorCode (*)(Mat, Vec, Vec))f;
1667:     }
1668:     break;
1669:   case MATOP_MULT_HERMITIAN_TRANSPOSE:
1670:     if (shell->managescalingshifts) {
1671:       shell->ops->multhermitiantranspose = (PetscErrorCode (*)(Mat, Vec, Vec))f;
1672:       mat->ops->multhermitiantranspose   = MatMultHermitianTranspose_Shell;
1673:     } else {
1674:       shell->ops->multhermitiantranspose = NULL;
1675:       mat->ops->multhermitiantranspose   = (PetscErrorCode (*)(Mat, Vec, Vec))f;
1676:     }
1677:     break;
1678:   default:
1679:     (((PetscErrorCodeFn **)mat->ops)[op]) = f;
1680:     break;
1681:   }
1682:   PetscFunctionReturn(PETSC_SUCCESS);
1683: }

1685: static PetscErrorCode MatShellGetOperation_Shell(Mat mat, MatOperation op, PetscErrorCodeFn **f)
1686: {
1687:   Mat_Shell *shell = (Mat_Shell *)mat->data;

1689:   PetscFunctionBegin;
1690:   switch (op) {
1691:   case MATOP_DESTROY:
1692:     *f = (PetscErrorCodeFn *)shell->ops->destroy;
1693:     break;
1694:   case MATOP_VIEW:
1695:     *f = (PetscErrorCodeFn *)mat->ops->view;
1696:     break;
1697:   case MATOP_COPY:
1698:     *f = (PetscErrorCodeFn *)shell->ops->copy;
1699:     break;
1700:   case MATOP_DIAGONAL_SET:
1701:   case MATOP_DIAGONAL_SCALE:
1702:   case MATOP_SHIFT:
1703:   case MATOP_SCALE:
1704:   case MATOP_AXPY:
1705:   case MATOP_ZERO_ROWS:
1706:   case MATOP_ZERO_ROWS_COLUMNS:
1707:     *f = (((PetscErrorCodeFn **)mat->ops)[op]);
1708:     break;
1709:   case MATOP_GET_DIAGONAL:
1710:     if (shell->ops->getdiagonal) *f = (PetscErrorCodeFn *)shell->ops->getdiagonal;
1711:     else *f = (((PetscErrorCodeFn **)mat->ops)[op]);
1712:     break;
1713:   case MATOP_GET_DIAGONAL_BLOCK:
1714:     if (shell->ops->getdiagonalblock) *f = (PetscErrorCodeFn *)shell->ops->getdiagonalblock;
1715:     else *f = (((PetscErrorCodeFn **)mat->ops)[op]);
1716:     break;
1717:   case MATOP_MULT:
1718:     if (shell->ops->mult) *f = (PetscErrorCodeFn *)shell->ops->mult;
1719:     else *f = (((PetscErrorCodeFn **)mat->ops)[op]);
1720:     break;
1721:   case MATOP_MULT_TRANSPOSE:
1722:     if (shell->ops->multtranspose) *f = (PetscErrorCodeFn *)shell->ops->multtranspose;
1723:     else *f = (((PetscErrorCodeFn **)mat->ops)[op]);
1724:     break;
1725:   case MATOP_MULT_HERMITIAN_TRANSPOSE:
1726:     if (shell->ops->multhermitiantranspose) *f = (PetscErrorCodeFn *)shell->ops->multhermitiantranspose;
1727:     else *f = (((PetscErrorCodeFn **)mat->ops)[op]);
1728:     break;
1729:   default:
1730:     *f = (((PetscErrorCodeFn **)mat->ops)[op]);
1731:   }
1732:   PetscFunctionReturn(PETSC_SUCCESS);
1733: }

1735: /*MC
1736:   MATSHELL - MATSHELL = "shell" - A matrix type to be used to define your own matrix type with its own data structure -- perhaps matrix-free.

1738:   Level: advanced

1740:   Notes:
1741:   See `MatCreateShell()` for details on the usage of `MATSHELL`

1743:   `PCSHELL` can be used in conjunction with `MATSHELL` to provide a custom preconditioner appropriate for your `MATSHELL`. Since
1744:   many standard preconditioners such as `PCILU` depend on having an explicit representation of the matrix entries they cannot be used
1745:   directly with `MATSHELL`.

1747: .seealso: [](ch_matrices), `Mat`, `MatCreateShell()`, `PCSHELL`
1748: M*/

1750: PETSC_EXTERN PetscErrorCode MatCreate_Shell(Mat A)
1751: {
1752:   Mat_Shell *b;

1754:   PetscFunctionBegin;
1755:   PetscCall(PetscNew(&b));
1756:   A->data   = (void *)b;
1757:   A->ops[0] = MatOps_Values;

1759:   b->ctxcontainer        = NULL;
1760:   b->vshift              = 0.0;
1761:   b->vscale              = 1.0;
1762:   b->managescalingshifts = PETSC_TRUE;
1763:   A->assembled           = PETSC_TRUE;
1764:   A->preallocated        = PETSC_FALSE;

1766:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellGetContext_C", MatShellGetContext_Shell));
1767:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetContext_C", MatShellSetContext_Shell));
1768:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetContextDestroy_C", MatShellSetContextDestroy_Shell));
1769:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetVecType_C", MatShellSetVecType_Shell));
1770:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetManageScalingShifts_C", MatShellSetManageScalingShifts_Shell));
1771:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellGetScalingShifts_C", MatShellGetScalingShifts_Shell));
1772:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetOperation_C", MatShellSetOperation_Shell));
1773:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellGetOperation_C", MatShellGetOperation_Shell));
1774:   PetscCall(PetscObjectComposeFunction((PetscObject)A, "MatShellSetMatProductOperation_C", MatShellSetMatProductOperation_Shell));
1775:   PetscCall(PetscObjectChangeTypeName((PetscObject)A, MATSHELL));
1776:   PetscFunctionReturn(PETSC_SUCCESS);
1777: }

1779: /*@C
1780:   MatCreateShell - Creates a new matrix of `MatType` `MATSHELL` for use with a user-defined
1781:   private matrix data storage format.

1783:   Collective

1785:   Input Parameters:
1786: + comm - MPI communicator
1787: . m    - number of local rows (or `PETSC_DECIDE` to have calculated if `M` is given)
1788: . n    - number of local columns (or `PETSC_DECIDE` to have calculated if `N` is given)
1789: . M    - number of global rows (may be `PETSC_DETERMINE` to have calculated if `m` is given)
1790: . N    - number of global columns (may be `PETSC_DETERMINE` to have calculated if `n` is given)
1791: - ctx  - pointer to data needed by the shell matrix routines

1793:   Output Parameter:
1794: . A - the matrix

1796:   Level: advanced

1798:   Example Usage:
1799: .vb
1800:   extern PetscErrorCode mult(Mat, Vec, Vec);

1802:   MatCreateShell(comm, m, n, M, N, ctx, &mat);
1803:   MatShellSetOperation(mat, MATOP_MULT, (void(*)(void))mult);
1804:   MatShellSetContext(mat,ctx);
1805:   // Use matrix for operations that have been set
1806:   MatDestroy(mat);
1807: .ve

1809:   Notes:
1810:   The shell matrix type is intended to provide a simple way for users to write a custom matrix specifically for their application.

1812:   `MatCreateShell()` is used in conjunction with `MatShellSetContext()` and `MatShellSetOperation()`.

1814:   PETSc requires that matrices and vectors being used for certain
1815:   operations are partitioned accordingly.  For example, when
1816:   creating a shell matrix, `A`, that supports parallel matrix-vector
1817:   products using `MatMult`(A,x,y) the user should set the number
1818:   of local matrix rows to be the number of local elements of the
1819:   corresponding result vector, y. Note that this is information is
1820:   required for use of the matrix interface routines, even though
1821:   the shell matrix may not actually be physically partitioned.
1822:   For example,

1824: .vb
1825:      Vec x, y
1826:      extern PetscErrorCode mult(Mat,Vec,Vec);
1827:      Mat A

1829:      VecCreateMPI(comm,PETSC_DECIDE,M,&y);
1830:      VecCreateMPI(comm,PETSC_DECIDE,N,&x);
1831:      VecGetLocalSize(y,&m);
1832:      VecGetLocalSize(x,&n);
1833:      MatCreateShell(comm,m,n,M,N,ctx,&A);
1834:      MatShellSetOperation(mat,MATOP_MULT,(void(*)(void))mult);
1835:      MatMult(A,x,y);
1836:      MatDestroy(&A);
1837:      VecDestroy(&y);
1838:      VecDestroy(&x);
1839: .ve

1841:   `MATSHELL` handles `MatShift()`, `MatDiagonalSet()`, `MatDiagonalScale()`, `MatAXPY()`, `MatScale()`, `MatZeroRows()` and `MatZeroRowsColumns()`
1842:   internally, so these  operations cannot be overwritten unless `MatShellSetManageScalingShifts()` is called.

1844:   Developer Notes:
1845:   For rectangular matrices do all the scalings and shifts make sense?

1847:   Regarding shifting and scaling. The general form is

1849:   diag(left)(vscale*A + diag(dshift) + vshift I)diag(right)

1851:   The order you apply the operations is important. For example if you have a dshift then
1852:   apply a MatScale(s) you get s*vscale*A + s*diag(shift). But if you first scale and then shift
1853:   you get s*vscale*A + diag(shift)

1855:   A is the user provided function.

1857:   `KSP`/`PC` uses changes in the `Mat`'s "state" to decide if preconditioners need to be rebuilt `PCSetUp()` only calls the setup() for
1858:   for the `PC` implementation if the `Mat` state has increased from the previous call. Thus to get changes in a `MATSHELL` to trigger
1859:   an update in the preconditioner you must call `MatAssemblyBegin()` and `MatAssemblyEnd()` or `PetscObjectStateIncrease`((`PetscObject`)mat);
1860:   each time the `MATSHELL` matrix has changed.

1862:   Matrix-matrix product operations can be specified using `MatShellSetMatProductOperation()`

1864:   Calling `MatAssemblyBegin()`/`MatAssemblyEnd()` on a `MATSHELL` removes any previously supplied shift and scales that were provided
1865:   with `MatDiagonalSet()`, `MatShift()`, `MatScale()`, or `MatDiagonalScale()`.

1867:   Fortran Notes:
1868:   To use this from Fortran with a `ctx` you must write an interface definition for this
1869:   function and for `MatShellGetContext()` that tells Fortran the Fortran derived data type you are passing
1870:   in as the `ctx` argument.

1872: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatShellSetOperation()`, `MatHasOperation()`, `MatShellGetContext()`, `MatShellSetContext()`, `MatShellSetManageScalingShifts()`, `MatShellSetMatProductOperation()`
1873: @*/
1874: PetscErrorCode MatCreateShell(MPI_Comm comm, PetscInt m, PetscInt n, PetscInt M, PetscInt N, PetscCtx ctx, Mat *A)
1875: {
1876:   PetscFunctionBegin;
1877:   PetscCall(MatCreate(comm, A));
1878:   PetscCall(MatSetSizes(*A, m, n, M, N));
1879:   PetscCall(MatSetType(*A, MATSHELL));
1880:   PetscCall(MatShellSetContext(*A, ctx));
1881:   PetscCall(MatSetUp(*A));
1882:   PetscFunctionReturn(PETSC_SUCCESS);
1883: }

1885: /*@
1886:   MatShellSetContext - sets the context for a `MATSHELL` shell matrix

1888:   Logically Collective

1890:   Input Parameters:
1891: + mat - the `MATSHELL` shell matrix
1892: - ctx - the context

1894:   Level: advanced

1896:   Note:
1897:   This provides an easy way, along with `MatCreateShell()` and `MatShellSetOperation()` to provide a custom matrix format
1898:   specifically for your application.

1900:   Fortran Notes:
1901:   You must write a Fortran interface definition for this
1902:   function that tells Fortran the Fortran derived data type that you are passing in as the `ctx` argument.

1904: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`
1905: @*/
1906: PetscErrorCode MatShellSetContext(Mat mat, PetscCtx ctx)
1907: {
1908:   PetscFunctionBegin;
1910:   PetscTryMethod(mat, "MatShellSetContext_C", (Mat, void *), (mat, ctx));
1911:   PetscFunctionReturn(PETSC_SUCCESS);
1912: }

1914: /*@C
1915:   MatShellSetContextDestroy - sets the destroy function for a `MATSHELL` shell matrix context

1917:   Logically Collective

1919:   Input Parameters:
1920: + mat - the shell matrix
1921: - f   - the context destroy function, see `PetscCtxDestroyFn` for calling sequence

1923:   Level: advanced

1925:   Note:
1926:   If the `MatShell` is never duplicated, the behavior of this function is equivalent
1927:   to `MatShellSetOperation`(`Mat`,`MATOP_DESTROY`,f). However, `MatShellSetContextDestroy()`
1928:   ensures proper reference counting for the user provided context data in the case that
1929:   the `MATSHELL` is duplicated.

1931: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellSetContext()`,
1932:           `PetscCtxDestroyFn`
1933: @*/
1934: PetscErrorCode MatShellSetContextDestroy(Mat mat, PetscCtxDestroyFn *f)
1935: {
1936:   PetscFunctionBegin;
1938:   PetscTryMethod(mat, "MatShellSetContextDestroy_C", (Mat, PetscCtxDestroyFn *), (mat, f));
1939:   PetscFunctionReturn(PETSC_SUCCESS);
1940: }

1942: /*@C
1943:   MatShellSetVecType - Sets the `VecType` of `Vec` returned by `MatCreateVecs()`

1945:   Logically Collective

1947:   Input Parameters:
1948: + mat   - the `MATSHELL` shell matrix
1949: - vtype - type to use for creating vectors

1951:   Level: advanced

1953: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateVecs()`
1954: @*/
1955: PetscErrorCode MatShellSetVecType(Mat mat, VecType vtype)
1956: {
1957:   PetscFunctionBegin;
1958:   PetscTryMethod(mat, "MatShellSetVecType_C", (Mat, VecType), (mat, vtype));
1959:   PetscFunctionReturn(PETSC_SUCCESS);
1960: }

1962: /*@
1963:   MatShellSetManageScalingShifts - Allows the user to control the scaling and shift operations of the `MATSHELL`. Must be called immediately
1964:   after `MatCreateShell()`

1966:   Logically Collective

1968:   Input Parameter:
1969: . A - the `MATSHELL` shell matrix

1971:   Level: advanced

1973: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellSetContext()`, `MatShellSetOperation()`
1974: @*/
1975: PetscErrorCode MatShellSetManageScalingShifts(Mat A)
1976: {
1977:   PetscFunctionBegin;
1979:   PetscTryMethod(A, "MatShellSetManageScalingShifts_C", (Mat), (A));
1980:   PetscFunctionReturn(PETSC_SUCCESS);
1981: }

1983: /*@C
1984:   MatShellGetScalingShifts - Gets members of a `MATSHELL` used internally for scaling and
1985:   shifting the `Mat` or calling `MatAXPY()`, `MatZeroRows()`, or `MatZeroRowsColumns()` with it

1987:   Logically Collective

1989:   Input Parameter:
1990: . A - the `MATSHELL` shell matrix

1992:   Output Parameters:
1993: + vshift - `PetscScalar` pointer (can be `NULL`), see `MatShift()`, or `MAT_SHELL_NOT_ALLOWED` if the internal shift should be 0
1994: . vscale - `PetscScalar` pointer (can be `NULL`), see `MatScale()`, or `MAT_SHELL_NOT_ALLOWED` if the internal scaling should be 1
1995: . dshift - `Vec` pointer (can be `NULL`), see `MatDiagonalSet()`, or `MAT_SHELL_NOT_ALLOWED` if the internal shift should be `NULL`
1996: . left   - `Vec` pointer (can be `NULL`), see `MatDiagonalScale()`, or `MAT_SHELL_NOT_ALLOWED` if the internal scaling should be `NULL`
1997: . right  - `Vec` pointer (can be `NULL`), see `MatDiagonalScale()`, or `MAT_SHELL_NOT_ALLOWED` if the internal scaling should be `NULL`
1998: . axpy   - `Mat` pointer (can be `NULL`), or `MAT_SHELL_NOT_ALLOWED` if `MatAXPY()` should have not been called on `A`
1999: . zrows  - `Vec` pointer (can be `NULL`), or `MAT_SHELL_NOT_ALLOWED` if `MatZeroRows()` should have not been called on `A`
2000: - zcols  - `Vec` pointer (can be `NULL`), or `MAT_SHELL_NOT_ALLOWED` if `MatZeroRowsColumns()` should have not been called on `A`

2002:   Level: advanced

2004:   Developer Notes:
2005:   This is mostly useful to check for corner-cases in `MatType` deriving from
2006:   `MATSHELL`, e.g, `MATCOMPOSITE` or `MATTRANSPOSEVIRTUAL`, since scaling and
2007:   shifts often require extra work which is not always implemented.

2009: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShift()`, `MatScale()`, `MatDiagonalSet()`, `MatDiagonalScale()`, `MatAXPY()`, `MatZeroRows()`, `MatZeroRowsColumns()`, `MatShellSetManageScalingShifts()`
2010: @*/
2011: PetscErrorCode MatShellGetScalingShifts(Mat A, PetscScalar *vshift, PetscScalar *vscale, Vec *dshift, Vec *left, Vec *right, Mat *axpy, IS *zrows, IS *zcols)
2012: {
2013:   PetscFunctionBegin;
2015:   PetscTryMethod(A, "MatShellGetScalingShifts_C", (Mat, PetscScalar *, PetscScalar *, Vec *, Vec *, Vec *, Mat *, IS *, IS *), (A, vshift, vscale, dshift, left, right, axpy, zrows, zcols));
2016:   PetscFunctionReturn(PETSC_SUCCESS);
2017: }

2019: /*@C
2020:   MatShellTestMult - Compares the multiply routine provided to the `MATSHELL` with differencing on a given function.

2022:   Logically Collective; No Fortran Support

2024:   Input Parameters:
2025: + mat  - the `MATSHELL` shell matrix
2026: . f    - the function
2027: . base - differences are computed around this vector, see `MatMFFDSetBase()`, for Jacobians this is the point at which the Jacobian is being evaluated
2028: - ctx  - an optional context for the function

2030:   Output Parameter:
2031: . flg - `PETSC_TRUE` if the multiply is likely correct

2033:   Options Database Key:
2034: . -mat_shell_test_mult_view - print if any differences are detected between the products and print the difference

2036:   Level: advanced

2038: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellTestMultTranspose()`
2039: @*/
2040: PetscErrorCode MatShellTestMult(Mat mat, PetscErrorCode (*f)(void *, Vec, Vec), Vec base, PetscCtx ctx, PetscBool *flg)
2041: {
2042:   PetscInt  m, n;
2043:   Mat       mf, Dmf, Dmat, Ddiff;
2044:   PetscReal Diffnorm, Dmfnorm;
2045:   PetscBool v = PETSC_FALSE, flag = PETSC_TRUE;

2047:   PetscFunctionBegin;
2049:   PetscCall(PetscOptionsHasName(NULL, ((PetscObject)mat)->prefix, "-mat_shell_test_mult_view", &v));
2050:   PetscCall(MatGetLocalSize(mat, &m, &n));
2051:   PetscCall(MatCreateMFFD(PetscObjectComm((PetscObject)mat), m, n, PETSC_DECIDE, PETSC_DECIDE, &mf));
2052:   PetscCall(MatMFFDSetFunction(mf, f, ctx));
2053:   PetscCall(MatMFFDSetBase(mf, base, NULL));

2055:   PetscCall(MatComputeOperator(mf, MATAIJ, &Dmf));
2056:   PetscCall(MatComputeOperator(mat, MATAIJ, &Dmat));

2058:   PetscCall(MatDuplicate(Dmat, MAT_COPY_VALUES, &Ddiff));
2059:   PetscCall(MatAXPY(Ddiff, -1.0, Dmf, DIFFERENT_NONZERO_PATTERN));
2060:   PetscCall(MatNorm(Ddiff, NORM_FROBENIUS, &Diffnorm));
2061:   PetscCall(MatNorm(Dmf, NORM_FROBENIUS, &Dmfnorm));
2062:   if (Diffnorm / Dmfnorm > 10 * PETSC_SQRT_MACHINE_EPSILON) {
2063:     flag = PETSC_FALSE;
2064:     if (v) {
2065:       PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL and matrix-free multiple appear to produce different results.\n Norm Ratio %g Difference results followed by finite difference one\n", (double)(Diffnorm / Dmfnorm)));
2066:       PetscCall(MatViewFromOptions(Ddiff, (PetscObject)mat, "-mat_shell_test_mult_view"));
2067:       PetscCall(MatViewFromOptions(Dmf, (PetscObject)mat, "-mat_shell_test_mult_view"));
2068:       PetscCall(MatViewFromOptions(Dmat, (PetscObject)mat, "-mat_shell_test_mult_view"));
2069:     }
2070:   } else if (v) {
2071:     PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL and matrix-free multiple appear to produce the same results\n"));
2072:   }
2073:   if (flg) *flg = flag;
2074:   PetscCall(MatDestroy(&Ddiff));
2075:   PetscCall(MatDestroy(&mf));
2076:   PetscCall(MatDestroy(&Dmf));
2077:   PetscCall(MatDestroy(&Dmat));
2078:   PetscFunctionReturn(PETSC_SUCCESS);
2079: }

2081: /*@C
2082:   MatShellTestMultTranspose - Compares the multiply transpose routine provided to the `MATSHELL` with differencing on a given function.

2084:   Logically Collective; No Fortran Support

2086:   Input Parameters:
2087: + mat  - the `MATSHELL` shell matrix
2088: . f    - the function
2089: . base - differences are computed around this vector, see `MatMFFDSetBase()`, for Jacobians this is the point at which the Jacobian is being evaluated
2090: - ctx  - an optional context for the function

2092:   Output Parameter:
2093: . flg - `PETSC_TRUE` if the multiply is likely correct

2095:   Options Database Key:
2096: . -mat_shell_test_mult_view - print if any differences are detected between the products and print the difference

2098:   Level: advanced

2100: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellTestMult()`
2101: @*/
2102: PetscErrorCode MatShellTestMultTranspose(Mat mat, PetscErrorCode (*f)(void *, Vec, Vec), Vec base, PetscCtx ctx, PetscBool *flg)
2103: {
2104:   Vec       x, y, z;
2105:   PetscInt  m, n, M, N;
2106:   Mat       mf, Dmf, Dmat, Ddiff;
2107:   PetscReal Diffnorm, Dmfnorm;
2108:   PetscBool v = PETSC_FALSE, flag = PETSC_TRUE;

2110:   PetscFunctionBegin;
2112:   PetscCall(PetscOptionsHasName(NULL, ((PetscObject)mat)->prefix, "-mat_shell_test_mult_transpose_view", &v));
2113:   PetscCall(MatCreateVecs(mat, &x, &y));
2114:   PetscCall(VecDuplicate(y, &z));
2115:   PetscCall(MatGetLocalSize(mat, &m, &n));
2116:   PetscCall(MatGetSize(mat, &M, &N));
2117:   PetscCall(MatCreateMFFD(PetscObjectComm((PetscObject)mat), m, n, M, N, &mf));
2118:   PetscCall(MatMFFDSetFunction(mf, f, ctx));
2119:   PetscCall(MatMFFDSetBase(mf, base, NULL));
2120:   PetscCall(MatComputeOperator(mf, MATAIJ, &Dmf));
2121:   PetscCall(MatTranspose(Dmf, MAT_INPLACE_MATRIX, &Dmf));
2122:   PetscCall(MatComputeOperatorTranspose(mat, MATAIJ, &Dmat));

2124:   PetscCall(MatDuplicate(Dmat, MAT_COPY_VALUES, &Ddiff));
2125:   PetscCall(MatAXPY(Ddiff, -1.0, Dmf, DIFFERENT_NONZERO_PATTERN));
2126:   PetscCall(MatNorm(Ddiff, NORM_FROBENIUS, &Diffnorm));
2127:   PetscCall(MatNorm(Dmf, NORM_FROBENIUS, &Dmfnorm));
2128:   if (Diffnorm / Dmfnorm > 10 * PETSC_SQRT_MACHINE_EPSILON) {
2129:     flag = PETSC_FALSE;
2130:     if (v) {
2131:       PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL and matrix-free multiple appear to produce different results.\n Norm Ratio %g Difference results followed by finite difference one\n", (double)(Diffnorm / Dmfnorm)));
2132:       PetscCall(MatViewFromOptions(Ddiff, (PetscObject)mat, "-mat_shell_test_mult_transpose_view"));
2133:       PetscCall(MatViewFromOptions(Dmf, (PetscObject)mat, "-mat_shell_test_mult_transpose_view"));
2134:       PetscCall(MatViewFromOptions(Dmat, (PetscObject)mat, "-mat_shell_test_mult_transpose_view"));
2135:     }
2136:   } else if (v) {
2137:     PetscCall(PetscPrintf(PetscObjectComm((PetscObject)mat), "MATSHELL transpose and matrix-free multiple appear to produce the same results\n"));
2138:   }
2139:   if (flg) *flg = flag;
2140:   PetscCall(MatDestroy(&mf));
2141:   PetscCall(MatDestroy(&Dmat));
2142:   PetscCall(MatDestroy(&Ddiff));
2143:   PetscCall(MatDestroy(&Dmf));
2144:   PetscCall(VecDestroy(&x));
2145:   PetscCall(VecDestroy(&y));
2146:   PetscCall(VecDestroy(&z));
2147:   PetscFunctionReturn(PETSC_SUCCESS);
2148: }

2150: /*@C
2151:   MatShellSetOperation - Allows user to set a matrix operation for a `MATSHELL` shell matrix.

2153:   Logically Collective

2155:   Input Parameters:
2156: + mat - the `MATSHELL` shell matrix
2157: . op  - the name of the operation
2158: - g   - the function that provides the operation.

2160:   Level: advanced

2162:   Example Usage:
2163: .vb
2164:   extern PetscErrorCode usermult(Mat, Vec, Vec);

2166:   MatCreateShell(comm, m, n, M, N, ctx, &A);
2167:   MatShellSetOperation(A, MATOP_MULT, (void(*)(void))usermult);
2168: .ve

2170:   Notes:
2171:   See the file include/petscmat.h for a complete list of matrix
2172:   operations, which all have the form MATOP_<OPERATION>, where
2173:   <OPERATION> is the name (in all capital letters) of the
2174:   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).

2176:   All user-provided functions (except for `MATOP_DESTROY`) should have the same calling
2177:   sequence as the usual matrix interface routines, since they
2178:   are intended to be accessed via the usual matrix interface
2179:   routines, e.g.,
2180: .vb
2181:   MatMult(Mat, Vec, Vec) -> usermult(Mat, Vec, Vec)
2182: .ve

2184:   In particular each function MUST return an error code of `PETSC_SUCCESS` on success and
2185:   nonzero on failure.

2187:   Within each user-defined routine, the user should call
2188:   `MatShellGetContext()` to obtain the user-defined context that was
2189:   set by `MatCreateShell()`.

2191:   Use `MatSetOperation()` to set an operation for any matrix type. For matrix product operations (i.e. `MatMatXXX()`, `MatTransposeMatXXX()` etc)
2192:   use `MatShellSetMatProductOperation()`

2194:   Fortran Note:
2195:   For `MatCreateVecs()` the user code should check if the input left or right vector is -1 and in that case not
2196:   generate a vector. See `src/mat/tests/ex120f.F`

2198: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellGetOperation()`, `MatShellSetContext()`, `MatSetOperation()`, `MatShellSetManageScalingShifts()`, `MatShellSetMatProductOperation()`
2199: @*/
2200: PetscErrorCode MatShellSetOperation(Mat mat, MatOperation op, PetscErrorCodeFn *g)
2201: {
2202:   PetscFunctionBegin;
2204:   PetscTryMethod(mat, "MatShellSetOperation_C", (Mat, MatOperation, PetscErrorCodeFn *), (mat, op, g));
2205:   PetscFunctionReturn(PETSC_SUCCESS);
2206: }

2208: /*@C
2209:   MatShellGetOperation - Gets a matrix function for a `MATSHELL` shell matrix.

2211:   Not Collective

2213:   Input Parameters:
2214: + mat - the `MATSHELL` shell matrix
2215: - op  - the name of the operation

2217:   Output Parameter:
2218: . g - the function that provides the operation.

2220:   Level: advanced

2222:   Notes:
2223:   See the file include/petscmat.h for a complete list of matrix
2224:   operations, which all have the form MATOP_<OPERATION>, where
2225:   <OPERATION> is the name (in all capital letters) of the
2226:   user interface routine (e.g., `MatMult()` -> `MATOP_MULT`).

2228:   All user-provided functions have the same calling
2229:   sequence as the usual matrix interface routines, since they
2230:   are intended to be accessed via the usual matrix interface
2231:   routines, e.g.,
2232: .vb
2233:   MatMult(Mat, Vec, Vec) -> usermult(Mat, Vec, Vec)
2234: .ve

2236:   Within each user-defined routine, the user should call
2237:   `MatShellGetContext()` to obtain the user-defined context that was
2238:   set by `MatCreateShell()`.

2240: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MatCreateShell()`, `MatShellGetContext()`, `MatShellSetOperation()`, `MatShellSetContext()`
2241: @*/
2242: PetscErrorCode MatShellGetOperation(Mat mat, MatOperation op, PetscErrorCodeFn **g)
2243: {
2244:   PetscFunctionBegin;
2246:   PetscUseMethod(mat, "MatShellGetOperation_C", (Mat, MatOperation, PetscErrorCodeFn **), (mat, op, g));
2247:   PetscFunctionReturn(PETSC_SUCCESS);
2248: }

2250: /*@
2251:   MatIsShell - Inquires if a matrix is derived from `MATSHELL`

2253:   Input Parameter:
2254: . mat - the matrix

2256:   Output Parameter:
2257: . flg - the Boolean value

2259:   Level: developer

2261: .seealso: [](ch_matrices), `Mat`, `MATSHELL`, `MATMFFD`, `MatCreateShell()`, `MATTRANSPOSEVIRTUAL`, `MATSCHURCOMPLEMENT`
2262: @*/
2263: PetscErrorCode MatIsShell(Mat mat, PetscBool *flg)
2264: {
2265:   PetscFunctionBegin;
2267:   PetscAssertPointer(flg, 2);
2268:   *flg = (PetscBool)(mat->ops->destroy == MatDestroy_Shell);
2269:   PetscFunctionReturn(PETSC_SUCCESS);
2270: }