Actual source code: snespatch.c

  1: /*
  2:       Defines a SNES that can consist of a collection of SNESes on patches of the domain
  3: */
  4: #include <petsc/private/vecimpl.h>
  5: #include <petsc/private/snesimpl.h>
  6: #include <petsc/private/pcpatchimpl.h>
  7: #include <petscsf.h>
  8: #include <petscsection.h>

 10: typedef struct {
 11:   PC pc; /* The linear patch preconditioner */
 12: } SNES_Patch;

 14: static PetscErrorCode SNESPatchComputeResidual_Private(SNES snes, Vec x, Vec F, PetscCtx ctx)
 15: {
 16:   PC                 pc      = (PC)ctx;
 17:   PC_PATCH          *pcpatch = (PC_PATCH *)pc->data;
 18:   PetscInt           pt, size, i;
 19:   const PetscInt    *indices;
 20:   const PetscScalar *X;
 21:   PetscScalar       *XWithAll;

 23:   PetscFunctionBegin;
 24:   /* scatter from x to patch->patchStateWithAll[pt] */
 25:   pt = pcpatch->currentPatch;
 26:   PetscCall(ISGetSize(pcpatch->dofMappingWithoutToWithAll[pt], &size));

 28:   PetscCall(ISGetIndices(pcpatch->dofMappingWithoutToWithAll[pt], &indices));
 29:   PetscCall(VecGetArrayRead(x, &X));
 30:   PetscCall(VecGetArray(pcpatch->patchStateWithAll, &XWithAll));

 32:   for (i = 0; i < size; ++i) XWithAll[indices[i]] = X[i];

 34:   PetscCall(VecRestoreArray(pcpatch->patchStateWithAll, &XWithAll));
 35:   PetscCall(VecRestoreArrayRead(x, &X));
 36:   PetscCall(ISRestoreIndices(pcpatch->dofMappingWithoutToWithAll[pt], &indices));

 38:   PetscCall(PCPatchComputeFunction_Internal(pc, pcpatch->patchStateWithAll, F, pt));
 39:   PetscFunctionReturn(PETSC_SUCCESS);
 40: }

 42: static PetscErrorCode SNESPatchComputeJacobian_Private(SNES snes, Vec x, Mat J, Mat M, PetscCtx ctx)
 43: {
 44:   PC                 pc      = (PC)ctx;
 45:   PC_PATCH          *pcpatch = (PC_PATCH *)pc->data;
 46:   PetscInt           pt, size, i;
 47:   const PetscInt    *indices;
 48:   const PetscScalar *X;
 49:   PetscScalar       *XWithAll;

 51:   PetscFunctionBegin;
 52:   /* scatter from x to patch->patchStateWithAll[pt] */
 53:   pt = pcpatch->currentPatch;
 54:   PetscCall(ISGetSize(pcpatch->dofMappingWithoutToWithAll[pt], &size));

 56:   PetscCall(ISGetIndices(pcpatch->dofMappingWithoutToWithAll[pt], &indices));
 57:   PetscCall(VecGetArrayRead(x, &X));
 58:   PetscCall(VecGetArray(pcpatch->patchStateWithAll, &XWithAll));

 60:   for (i = 0; i < size; ++i) XWithAll[indices[i]] = X[i];

 62:   PetscCall(VecRestoreArray(pcpatch->patchStateWithAll, &XWithAll));
 63:   PetscCall(VecRestoreArrayRead(x, &X));
 64:   PetscCall(ISRestoreIndices(pcpatch->dofMappingWithoutToWithAll[pt], &indices));

 66:   PetscCall(PCPatchComputeOperator_Internal(pc, pcpatch->patchStateWithAll, M, pcpatch->currentPatch, PETSC_FALSE));
 67:   PetscFunctionReturn(PETSC_SUCCESS);
 68: }

 70: static PetscErrorCode PCSetUp_PATCH_Nonlinear(PC pc)
 71: {
 72:   PC_PATCH   *patch = (PC_PATCH *)pc->data;
 73:   const char *prefix;
 74:   PetscInt    i, pStart, dof, maxDof = -1;

 76:   PetscFunctionBegin;
 77:   if (!pc->setupcalled) {
 78:     PetscCall(PetscMalloc1(patch->npatch, &patch->solver));
 79:     PetscCall(PCGetOptionsPrefix(pc, &prefix));
 80:     PetscCall(PetscSectionGetChart(patch->gtolCounts, &pStart, NULL));
 81:     for (i = 0; i < patch->npatch; ++i) {
 82:       SNES snes;

 84:       PetscCall(SNESCreate(PETSC_COMM_SELF, &snes));
 85:       PetscCall(SNESSetOptionsPrefix(snes, prefix));
 86:       PetscCall(SNESAppendOptionsPrefix(snes, "sub_"));
 87:       PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes, (PetscObject)pc, 2));
 88:       patch->solver[i] = (PetscObject)snes;

 90:       PetscCall(PetscSectionGetDof(patch->gtolCountsWithAll, i + pStart, &dof));
 91:       maxDof = PetscMax(maxDof, dof);
 92:     }
 93:     PetscCall(VecDuplicate(patch->localUpdate, &patch->localState));
 94:     PetscCall(VecDuplicate(patch->patchRHS, &patch->patchResidual));
 95:     PetscCall(VecDuplicate(patch->patchUpdate, &patch->patchState));

 97:     PetscCall(VecCreateSeq(PETSC_COMM_SELF, maxDof, &patch->patchStateWithAll));
 98:     PetscCall(VecSetUp(patch->patchStateWithAll));
 99:   }
100:   for (i = 0; i < patch->npatch; ++i) {
101:     SNES snes = (SNES)patch->solver[i];

103:     PetscCall(SNESSetFunction(snes, patch->patchResidual, SNESPatchComputeResidual_Private, pc));
104:     PetscCall(SNESSetJacobian(snes, patch->mat[i], patch->mat[i], SNESPatchComputeJacobian_Private, pc));
105:   }
106:   if (!pc->setupcalled && patch->optionsSet)
107:     for (i = 0; i < patch->npatch; ++i) PetscCall(SNESSetFromOptions((SNES)patch->solver[i]));
108:   PetscFunctionReturn(PETSC_SUCCESS);
109: }

111: static PetscErrorCode PCApply_PATCH_Nonlinear(PC pc, PetscInt i, Vec patchRHS, Vec patchUpdate)
112: {
113:   PC_PATCH *patch = (PC_PATCH *)pc->data;
114:   PetscInt  pStart, n;

116:   PetscFunctionBegin;
117:   patch->currentPatch = i;
118:   PetscCall(PetscLogEventBegin(PC_Patch_Solve, pc, 0, 0, 0));

120:   /* Scatter the overlapped global state to our patch state vector */
121:   PetscCall(PetscSectionGetChart(patch->gtolCounts, &pStart, NULL));
122:   PetscCall(PCPatch_ScatterLocal_Private(pc, i + pStart, patch->localState, patch->patchState, INSERT_VALUES, SCATTER_FORWARD, SCATTER_INTERIOR));
123:   PetscCall(PCPatch_ScatterLocal_Private(pc, i + pStart, patch->localState, patch->patchStateWithAll, INSERT_VALUES, SCATTER_FORWARD, SCATTER_WITHALL));

125:   PetscCall(MatGetLocalSize(patch->mat[i], NULL, &n));
126:   patch->patchState->map->n = n;
127:   patch->patchState->map->N = n;
128:   patchUpdate->map->n       = n;
129:   patchUpdate->map->N       = n;
130:   patchRHS->map->n          = n;
131:   patchRHS->map->N          = n;
132:   /* Set initial guess to be current state*/
133:   PetscCall(VecCopy(patch->patchState, patchUpdate));
134:   /* Solve for new state */
135:   PetscCall(SNESSolve((SNES)patch->solver[i], patchRHS, patchUpdate));
136:   /* To compute update, subtract off previous state */
137:   PetscCall(VecAXPY(patchUpdate, -1.0, patch->patchState));

139:   PetscCall(PetscLogEventEnd(PC_Patch_Solve, pc, 0, 0, 0));
140:   PetscFunctionReturn(PETSC_SUCCESS);
141: }

143: static PetscErrorCode PCReset_PATCH_Nonlinear(PC pc)
144: {
145:   PC_PATCH *patch = (PC_PATCH *)pc->data;
146:   PetscInt  i;

148:   PetscFunctionBegin;
149:   if (patch->solver) {
150:     for (i = 0; i < patch->npatch; ++i) PetscCall(SNESReset((SNES)patch->solver[i]));
151:   }

153:   PetscCall(VecDestroy(&patch->patchResidual));
154:   PetscCall(VecDestroy(&patch->patchState));
155:   PetscCall(VecDestroy(&patch->patchStateWithAll));

157:   PetscCall(VecDestroy(&patch->localState));
158:   PetscFunctionReturn(PETSC_SUCCESS);
159: }

161: static PetscErrorCode PCDestroy_PATCH_Nonlinear(PC pc)
162: {
163:   PC_PATCH *patch = (PC_PATCH *)pc->data;
164:   PetscInt  i;

166:   PetscFunctionBegin;
167:   if (patch->solver) {
168:     for (i = 0; i < patch->npatch; ++i) PetscCall(SNESDestroy((SNES *)&patch->solver[i]));
169:     PetscCall(PetscFree(patch->solver));
170:   }
171:   PetscFunctionReturn(PETSC_SUCCESS);
172: }

174: static PetscErrorCode PCUpdateMultiplicative_PATCH_Nonlinear(PC pc, PetscInt i, PetscInt pStart)
175: {
176:   PC_PATCH *patch = (PC_PATCH *)pc->data;

178:   PetscFunctionBegin;
179:   PetscCall(PCPatch_ScatterLocal_Private(pc, i + pStart, patch->patchUpdate, patch->localState, ADD_VALUES, SCATTER_REVERSE, SCATTER_INTERIOR));
180:   PetscFunctionReturn(PETSC_SUCCESS);
181: }

183: static PetscErrorCode SNESSetUp_Patch(SNES snes)
184: {
185:   SNES_Patch *patch = (SNES_Patch *)snes->data;
186:   DM          dm;
187:   Mat         dummy;
188:   Vec         F;
189:   PetscInt    n, N;

191:   PetscFunctionBegin;
192:   PetscCall(SNESGetDM(snes, &dm));
193:   PetscCall(PCSetDM(patch->pc, dm));
194:   PetscCall(SNESGetFunction(snes, &F, NULL, NULL));
195:   PetscCall(VecGetLocalSize(F, &n));
196:   PetscCall(VecGetSize(F, &N));
197:   PetscCall(MatCreateShell(PetscObjectComm((PetscObject)snes), n, n, N, N, (void *)snes, &dummy));
198:   PetscCall(PCSetOperators(patch->pc, dummy, dummy));
199:   PetscCall(MatDestroy(&dummy));
200:   PetscCall(PCSetUp(patch->pc));
201:   /* allocate workspace */
202:   PetscFunctionReturn(PETSC_SUCCESS);
203: }

205: static PetscErrorCode SNESReset_Patch(SNES snes)
206: {
207:   SNES_Patch *patch = (SNES_Patch *)snes->data;

209:   PetscFunctionBegin;
210:   PetscCall(PCReset(patch->pc));
211:   PetscFunctionReturn(PETSC_SUCCESS);
212: }

214: static PetscErrorCode SNESDestroy_Patch(SNES snes)
215: {
216:   SNES_Patch *patch = (SNES_Patch *)snes->data;

218:   PetscFunctionBegin;
219:   PetscCall(SNESReset_Patch(snes));
220:   PetscCall(PCDestroy(&patch->pc));
221:   PetscCall(PetscFree(snes->data));
222:   PetscFunctionReturn(PETSC_SUCCESS);
223: }

225: static PetscErrorCode SNESSetFromOptions_Patch(SNES snes, PetscOptionItems PetscOptionsObject)
226: {
227:   SNES_Patch *patch = (SNES_Patch *)snes->data;
228:   const char *prefix;

230:   PetscFunctionBegin;
231:   PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, &prefix));
232:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)patch->pc, prefix));
233:   PetscCall(PCSetFromOptions(patch->pc));
234:   PetscFunctionReturn(PETSC_SUCCESS);
235: }

237: static PetscErrorCode SNESView_Patch(SNES snes, PetscViewer viewer)
238: {
239:   SNES_Patch *patch = (SNES_Patch *)snes->data;
240:   PetscBool   isascii;

242:   PetscFunctionBegin;
243:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
244:   if (isascii) PetscCall(PetscViewerASCIIPrintf(viewer, "SNESPATCH\n"));
245:   PetscCall(PetscViewerASCIIPushTab(viewer));
246:   PetscCall(PCView(patch->pc, viewer));
247:   PetscCall(PetscViewerASCIIPopTab(viewer));
248:   PetscFunctionReturn(PETSC_SUCCESS);
249: }

251: static PetscErrorCode SNESSolve_Patch(SNES snes)
252: {
253:   SNES_Patch        *patch   = (SNES_Patch *)snes->data;
254:   PC_PATCH          *pcpatch = (PC_PATCH *)patch->pc->data;
255:   SNESLineSearch     ls;
256:   Vec                rhs, update, state, residual;
257:   const PetscScalar *globalState = NULL;
258:   PetscScalar       *localState  = NULL;
259:   PetscInt           its         = 0;
260:   PetscReal          xnorm = 0.0, ynorm = 0.0, fnorm = 0.0;

262:   PetscFunctionBegin;
263:   PetscCall(SNESGetSolution(snes, &state));
264:   PetscCall(SNESGetSolutionUpdate(snes, &update));
265:   PetscCall(SNESGetRhs(snes, &rhs));

267:   PetscCall(SNESGetFunction(snes, &residual, NULL, NULL));
268:   PetscCall(SNESGetLineSearch(snes, &ls));

270:   PetscCall(SNESSetConvergedReason(snes, SNES_CONVERGED_ITERATING));
271:   PetscCall(VecSet(update, 0.0));
272:   PetscCall(SNESComputeFunction(snes, state, residual));

274:   PetscCall(VecNorm(state, NORM_2, &xnorm));
275:   PetscCall(VecNorm(residual, NORM_2, &fnorm));
276:   SNESCheckFunctionDomainError(snes, fnorm);
277:   snes->ttol = fnorm * snes->rtol;

279:   if (snes->ops->converged) {
280:     PetscUseTypeMethod(snes, converged, its, xnorm, ynorm, fnorm, &snes->reason, snes->cnvP);
281:   } else {
282:     PetscCall(SNESConvergedSkip(snes, its, xnorm, ynorm, fnorm, &snes->reason, NULL));
283:   }
284:   PetscCall(SNESLogConvergenceHistory(snes, fnorm, 0)); /* should we count lits from the patches? */
285:   PetscCall(SNESMonitor(snes, its, fnorm));

287:   /* The main solver loop */
288:   for (its = 0; its < snes->max_its; its++) {
289:     PetscCall(SNESSetIterationNumber(snes, its));

291:     /* Scatter state vector to overlapped vector on all patches.
292:        The vector pcpatch->localState is scattered to each patch
293:        in PCApply_PATCH_Nonlinear. */
294:     PetscCall(VecGetArrayRead(state, &globalState));
295:     PetscCall(VecGetArray(pcpatch->localState, &localState));
296:     PetscCall(PetscSFBcastBegin(pcpatch->sectionSF, MPIU_SCALAR, globalState, localState, MPI_REPLACE));
297:     PetscCall(PetscSFBcastEnd(pcpatch->sectionSF, MPIU_SCALAR, globalState, localState, MPI_REPLACE));
298:     PetscCall(VecRestoreArray(pcpatch->localState, &localState));
299:     PetscCall(VecRestoreArrayRead(state, &globalState));

301:     /* The looping over patches happens here */
302:     PetscCall(PCApply(patch->pc, rhs, update));

304:     /* Apply a line search. This will often be basic with
305:        damping = 1/(max number of patches a dof can be in),
306:        but not always */
307:     PetscCall(VecScale(update, -1.0));
308:     PetscCall(SNESLineSearchApply(ls, state, residual, &fnorm, update));

310:     PetscCall(VecNorm(state, NORM_2, &xnorm));
311:     PetscCall(VecNorm(update, NORM_2, &ynorm));

313:     if (snes->ops->converged) {
314:       PetscUseTypeMethod(snes, converged, its, xnorm, ynorm, fnorm, &snes->reason, snes->cnvP);
315:     } else {
316:       PetscCall(SNESConvergedSkip(snes, its, xnorm, ynorm, fnorm, &snes->reason, NULL));
317:     }
318:     PetscCall(SNESLogConvergenceHistory(snes, fnorm, 0)); /* FIXME: should we count lits? */
319:     PetscCall(SNESMonitor(snes, its, fnorm));
320:   }

322:   if (its == snes->max_its) PetscCall(SNESSetConvergedReason(snes, SNES_DIVERGED_MAX_IT));
323:   PetscFunctionReturn(PETSC_SUCCESS);
324: }

326: /*MC
327:   SNESPATCH - Solve a nonlinear problem or apply a nonlinear smoother by composing together many nonlinear solvers on (often overlapping) patches {cite}`bruneknepleysmithtu15`

329:   Level: intermediate

331: .seealso: [](ch_snes), `SNESFAS`, `SNESCreate()`, `SNESSetType()`, `SNESType`, `SNES`, `PCPATCH`
332: M*/
333: PETSC_EXTERN PetscErrorCode SNESCreate_Patch(SNES snes)
334: {
335:   SNES_Patch    *patch;
336:   PC_PATCH      *patchpc;
337:   SNESLineSearch linesearch;

339:   PetscFunctionBegin;
340:   PetscCall(PetscNew(&patch));

342:   snes->ops->solve          = SNESSolve_Patch;
343:   snes->ops->setup          = SNESSetUp_Patch;
344:   snes->ops->reset          = SNESReset_Patch;
345:   snes->ops->destroy        = SNESDestroy_Patch;
346:   snes->ops->setfromoptions = SNESSetFromOptions_Patch;
347:   snes->ops->view           = SNESView_Patch;

349:   PetscCall(SNESGetLineSearch(snes, &linesearch));
350:   if (!((PetscObject)linesearch)->type_name) PetscCall(SNESLineSearchSetType(linesearch, SNESLINESEARCHBASIC));
351:   snes->usesksp = PETSC_FALSE;

353:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

355:   PetscCall(SNESParametersInitialize(snes));

357:   snes->data = (void *)patch;
358:   PetscCall(PCCreate(PetscObjectComm((PetscObject)snes), &patch->pc));
359:   PetscCall(PCSetType(patch->pc, PCPATCH));

361:   patchpc              = (PC_PATCH *)patch->pc->data;
362:   patchpc->classname   = "snes";
363:   patchpc->isNonlinear = PETSC_TRUE;

365:   patchpc->setupsolver          = PCSetUp_PATCH_Nonlinear;
366:   patchpc->applysolver          = PCApply_PATCH_Nonlinear;
367:   patchpc->resetsolver          = PCReset_PATCH_Nonlinear;
368:   patchpc->destroysolver        = PCDestroy_PATCH_Nonlinear;
369:   patchpc->updatemultiplicative = PCUpdateMultiplicative_PATCH_Nonlinear;
370:   PetscFunctionReturn(PETSC_SUCCESS);
371: }

373: /*@C
374:   SNESPatchSetDiscretisationInfo - Provide the per-subspace discretisation information required by a `SNESPATCH` to build patch problems

376:   Logically Collective

378:   Input Parameters:
379: + snes            - the `SNESPATCH` solver
380: . nsubspaces      - the number of discretisation subspaces (e.g. fields)
381: . dms             - array of length `nsubspaces` of `DM`s, one per subspace
382: . bs              - array of length `nsubspaces` giving the block size of each subspace
383: . nodesPerCell    - array of length `nsubspaces` giving the number of nodes per cell for each subspace
384: . cellNodeMap     - array of length `nsubspaces`; entry `i` is a cell-to-node map for subspace `i`
385: . subspaceOffsets - array of length `nsubspaces + 1` giving the starting global dof offset of each subspace
386: . numGhostBcs     - number of ghost (off-process) boundary-condition dofs
387: . ghostBcNodes    - array of length `numGhostBcs` of the ghost boundary-condition dof indices
388: . numGlobalBcs    - number of global boundary-condition dofs
389: - globalBcNodes   - array of length `numGlobalBcs` of the global boundary-condition dof indices

391:   Level: advanced

393:   Note:
394:   A `DM` must already be attached to `snes` (via `SNESSetDM()`) before calling this routine. Internally, the information is forwarded to the underlying `PCPATCH` via `PCPatchSetDiscretisationInfo()`.

396: .seealso: [](ch_snes), `SNESPATCH`, `PCPATCH`, `PCPatchSetDiscretisationInfo()`, `SNESPatchSetComputeOperator()`, `SNESPatchSetComputeFunction()`
397: @*/
398: PetscErrorCode SNESPatchSetDiscretisationInfo(SNES snes, PetscInt nsubspaces, DM dms[], PetscInt bs[], PetscInt nodesPerCell[], const PetscInt **cellNodeMap, const PetscInt subspaceOffsets[], PetscInt numGhostBcs, const PetscInt ghostBcNodes[], PetscInt numGlobalBcs, const PetscInt globalBcNodes[])
399: {
400:   SNES_Patch *patch = (SNES_Patch *)snes->data;
401:   DM          dm;

403:   PetscFunctionBegin;
404:   PetscCall(SNESGetDM(snes, &dm));
405:   PetscCheck(dm, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONGSTATE, "DM not yet set on patch SNES");
406:   PetscCall(PCSetDM(patch->pc, dm));
407:   PetscCall(PCPatchSetDiscretisationInfo(patch->pc, nsubspaces, dms, bs, nodesPerCell, cellNodeMap, subspaceOffsets, numGhostBcs, ghostBcNodes, numGlobalBcs, globalBcNodes));
408:   PetscFunctionReturn(PETSC_SUCCESS);
409: }

411: /*@C
412:   SNESPatchSetComputeOperator - Set the callback used to assemble the per-patch Jacobian for a `SNESPATCH` solver

414:   Logically Collective

416:   Input Parameters:
417: + snes - the `SNESPATCH` solver
418: . func - callback that assembles the patch Jacobian; forwarded to the underlying `PCPATCH` via `PCPatchSetComputeOperator()`
419: - ctx  - optional application context passed to `func`

421:   Calling sequence of `func`:
422: + pc               - the `PC` associated with the `SNESPATCH` solver
423: . point            - the point
424: . x                - the input solution (not used in linear problems)
425: . mat              - the patch matrix
426: . cellIS           - an array of the cell numbers
427: . n                - the size of `dofsArray`
428: . dofsArray        - the dofmap for the dofs to be solved for
429: . dofsArrayWithAll - the dofmap for all dofs on the patch
430: - ctx              - the application context

432:   Level: advanced

434: .seealso: [](ch_snes), `SNESPATCH`, `PCPATCH`, `PCPatchSetComputeOperator()`, `SNESPatchSetComputeFunction()`
435: @*/
436: PetscErrorCode SNESPatchSetComputeOperator(SNES snes, PetscErrorCode (*func)(PC pc, PetscInt point, Vec x, Mat mat, IS cellIS, PetscInt n, const PetscInt *dofsArray, const PetscInt *dofsArrayWithAll, PetscCtx ctx), PetscCtx ctx)
437: {
438:   SNES_Patch *patch = (SNES_Patch *)snes->data;

440:   PetscFunctionBegin;
441:   PetscCall(PCPatchSetComputeOperator(patch->pc, func, ctx));
442:   PetscFunctionReturn(PETSC_SUCCESS);
443: }

445: /*@C
446:   SNESPatchSetComputeFunction - Set the callback used to compute the per-patch nonlinear residual for a `SNESPATCH` solver

448:   Logically Collective

450:   Input Parameters:
451: + snes - the `SNESPATCH` solver
452: . func - callback that computes the patch residual; forwarded to the underlying `PCPATCH` via `PCPatchSetComputeFunction()`
453: - ctx  - optional application context passed to `func`

455:   Calling sequence of `func`:
456: + pc               - the `PC` associated with the `SNESPATCH` solver
457: . point            - the point
458: . x                - the input solution (not used in linear problems)
459: . f                - the patch residual vector
460: . cellIS           - an array of the cell numbers
461: . n                - the size of `dofsArray`
462: . dofsArray        - the dofmap for the dofs to be solved for
463: . dofsArrayWithAll - the dofmap for all dofs on the patch
464: - ctx              - the application context

466:   Level: advanced

468: .seealso: [](ch_snes), `SNESPATCH`, `PCPATCH`, `PCPatchSetComputeFunction()`, `SNESPatchSetComputeOperator()`
469: @*/
470: PetscErrorCode SNESPatchSetComputeFunction(SNES snes, PetscErrorCode (*func)(PC pc, PetscInt point, Vec x, Vec f, IS cellIS, PetscInt n, const PetscInt *dofsArray, const PetscInt *dofsArrayWithAll, PetscCtx ctx), PetscCtx ctx)
471: {
472:   SNES_Patch *patch = (SNES_Patch *)snes->data;

474:   PetscFunctionBegin;
475:   PetscCall(PCPatchSetComputeFunction(patch->pc, func, ctx));
476:   PetscFunctionReturn(PETSC_SUCCESS);
477: }

479: /*@C
480:   SNESPatchSetConstructType - Set the way patches are constructed for a `SNESPATCH` solver

482:   Logically Collective

484:   Input Parameters:
485: + snes  - the `SNESPATCH` solver
486: . ctype - the `PCPatchConstructType` selecting the patch construction strategy
487: . func  - user callback that builds the patches, used only when `ctype` is `PC_PATCH_USER` or `PC_PATCH_PYTHON`; may be `NULL` otherwise
488: - ctx   - optional application context passed to `func`

490:   Calling sequence of `func`:
491: + pc                - the `PC` associated with the `SNESPATCH` solver
492: . npatch            - number of patches
493: . patches           - the `IS` that define each patch
494: . patchIterationSet - how the patches are iterated over
495: - ctx               - optional application context

497:   Level: advanced

499: .seealso: [](ch_snes), `SNESPATCH`, `PCPATCH`, `PCPatchSetConstructType()`, `PCPatchConstructType`
500: @*/
501: PetscErrorCode SNESPatchSetConstructType(SNES snes, PCPatchConstructType ctype, PetscErrorCode (*func)(PC pc, PetscInt *npatch, IS *patches[], IS *patchIterationSet, PetscCtx ctx), PetscCtx ctx)
502: {
503:   SNES_Patch *patch = (SNES_Patch *)snes->data;

505:   PetscFunctionBegin;
506:   PetscCall(PCPatchSetConstructType(patch->pc, ctype, func, ctx));
507:   PetscFunctionReturn(PETSC_SUCCESS);
508: }

510: /*@
511:   SNESPatchSetCellNumbering - Set the `PetscSection` that provides a numbering of the cells used to define patches in a `SNESPATCH` solver

513:   Logically Collective

515:   Input Parameters:
516: + snes          - the `SNESPATCH` solver
517: - cellNumbering - the `PetscSection` giving the cell numbering; forwarded to the underlying `PCPATCH` via `PCPatchSetCellNumbering()`

519:   Level: advanced

521: .seealso: [](ch_snes), `SNESPATCH`, `PCPATCH`, `PCPatchSetCellNumbering()`, `PetscSection`
522: @*/
523: PetscErrorCode SNESPatchSetCellNumbering(SNES snes, PetscSection cellNumbering)
524: {
525:   SNES_Patch *patch = (SNES_Patch *)snes->data;

527:   PetscFunctionBegin;
528:   PetscCall(PCPatchSetCellNumbering(patch->pc, cellNumbering));
529:   PetscFunctionReturn(PETSC_SUCCESS);
530: }