Actual source code: dmplexts.c

  1: #include <petsc/private/dmpleximpl.h>
  2: #include <petsc/private/tsimpl.h>
  3: #include <petsc/private/snesimpl.h>
  4: #include <petscds.h>
  5: #include <petscfv.h>

  7: static PetscErrorCode DMTSConvertPlex(DM dm, DM *plex, PetscBool copy)
  8: {
  9:   PetscBool isPlex;

 11:   PetscFunctionBegin;
 12:   PetscCall(PetscObjectTypeCompare((PetscObject)dm, DMPLEX, &isPlex));
 13:   if (isPlex) {
 14:     *plex = dm;
 15:     PetscCall(PetscObjectReference((PetscObject)dm));
 16:   } else {
 17:     PetscCall(PetscObjectQuery((PetscObject)dm, "dm_plex", (PetscObject *)plex));
 18:     if (!*plex) {
 19:       PetscCall(DMConvert(dm, DMPLEX, plex));
 20:       PetscCall(PetscObjectCompose((PetscObject)dm, "dm_plex", (PetscObject)*plex));
 21:     } else {
 22:       PetscCall(PetscObjectReference((PetscObject)*plex));
 23:     }
 24:     if (copy) {
 25:       PetscCall(DMCopyDMTS(dm, *plex));
 26:       PetscCall(DMCopyDMSNES(dm, *plex));
 27:       PetscCall(DMCopyAuxiliaryVec(dm, *plex));
 28:     }
 29:   }
 30:   PetscFunctionReturn(PETSC_SUCCESS);
 31: }

 33: PetscErrorCode DMPlexTSComputeRHSFunctionFVMCEED(DM dm, PetscReal time, Vec locX, Vec F, void *user)
 34: {
 35: #ifdef PETSC_HAVE_LIBCEED
 36:   PetscFV    fv;
 37:   Vec        locF;
 38:   Ceed       ceed;
 39:   DMCeed     sd = dm->dmceed;
 40:   CeedVector clocX, clocF;
 41: #endif

 43: #ifdef PETSC_HAVE_LIBCEED
 44:   PetscFunctionBegin;
 45:   PetscCall(DMGetCeed(dm, &ceed));
 46:   PetscCheck(sd, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_WRONGSTATE, "This DM has no CEED data. Call DMCeedCreate() before computing the residual.");
 47:   if (time == 0.) PetscCall(DMCeedComputeGeometry(dm, sd));
 48:   PetscCall(DMGetField(dm, 0, NULL, (PetscObject *)&fv));
 49:   PetscCall(DMPlexInsertBoundaryValuesFVM(dm, fv, locX, time, NULL));
 50:   PetscCall(DMGetLocalVector(dm, &locF));
 51:   PetscCall(VecZeroEntries(locF));
 52:   PetscCall(VecGetCeedVectorRead(locX, ceed, &clocX));
 53:   PetscCall(VecGetCeedVector(locF, ceed, &clocF));
 54:   PetscCallCEED(CeedOperatorApplyAdd(sd->op, clocX, clocF, CEED_REQUEST_IMMEDIATE));
 55:   PetscCall(VecRestoreCeedVectorRead(locX, &clocX));
 56:   PetscCall(VecRestoreCeedVector(locF, &clocF));
 57:   PetscCall(DMLocalToGlobalBegin(dm, locF, ADD_VALUES, F));
 58:   PetscCall(DMLocalToGlobalEnd(dm, locF, ADD_VALUES, F));
 59:   PetscCall(DMRestoreLocalVector(dm, &locF));
 60:   PetscCall(VecViewFromOptions(F, NULL, "-fv_rhs_view"));
 61:   PetscFunctionReturn(PETSC_SUCCESS);
 62: #else
 63:   SETERRQ(PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "This requires libCEED. Reconfigure using --download-libceed");
 64: #endif
 65: }

 67: /*@
 68:   DMPlexTSComputeRHSFunctionFVM - Form the forcing `F` from the local input `locX` using pointwise functions specified by the user

 70:   Input Parameters:
 71: + dm   - The mesh
 72: . time - The time
 73: . locX - Local solution
 74: - user - The user context

 76:   Output Parameter:
 77: . F - Global output vector

 79:   Level: developer

 81: .seealso: [](ch_ts), `DMPLEX`, `TS`, `DMPlexComputeJacobianActionFEM()`
 82: @*/
 83: PetscErrorCode DMPlexTSComputeRHSFunctionFVM(DM dm, PetscReal time, Vec locX, Vec F, void *user)
 84: {
 85:   Vec          locF;
 86:   IS           cellIS;
 87:   DM           plex;
 88:   PetscInt     depth;
 89:   PetscFormKey key = {NULL, 0, 0, 0};

 91:   PetscFunctionBegin;
 92:   PetscCall(DMTSConvertPlex(dm, &plex, PETSC_TRUE));
 93:   PetscCall(DMPlexGetDepth(plex, &depth));
 94:   PetscCall(DMGetStratumIS(plex, "dim", depth, &cellIS));
 95:   if (!cellIS) PetscCall(DMGetStratumIS(plex, "depth", depth, &cellIS));
 96:   PetscCall(DMGetLocalVector(plex, &locF));
 97:   PetscCall(VecZeroEntries(locF));
 98:   PetscCall(DMPlexComputeResidual_Internal(plex, key, cellIS, time, locX, NULL, time, locF, user));
 99:   PetscCall(DMLocalToGlobalBegin(plex, locF, ADD_VALUES, F));
100:   PetscCall(DMLocalToGlobalEnd(plex, locF, ADD_VALUES, F));
101:   PetscCall(DMRestoreLocalVector(plex, &locF));
102:   PetscCall(ISDestroy(&cellIS));
103:   PetscCall(DMDestroy(&plex));
104:   PetscCall(VecViewFromOptions(F, NULL, "-fv_rhs_view"));
105:   PetscFunctionReturn(PETSC_SUCCESS);
106: }

108: /*@
109:   DMPlexTSComputeBoundary - Insert the essential boundary values into the local input `locX` and/or its time derivative `locX_t` using pointwise functions specified by the user

111:   Input Parameters:
112: + dm     - The mesh
113: . time   - The time
114: . locX   - Local solution
115: . locX_t - Local solution time derivative, or `NULL`
116: - user   - The user context

118:   Level: developer

120: .seealso: [](ch_ts), `DMPLEX`, `TS`, `DMPlexComputeJacobianActionFEM()`
121: @*/
122: PetscErrorCode DMPlexTSComputeBoundary(DM dm, PetscReal time, Vec locX, Vec locX_t, void *user)
123: {
124:   DM       plex;
125:   Vec      faceGeometryFVM = NULL;
126:   PetscInt Nf, f;

128:   PetscFunctionBegin;
129:   PetscCall(DMTSConvertPlex(dm, &plex, PETSC_TRUE));
130:   PetscCall(DMGetNumFields(plex, &Nf));
131:   if (!locX_t) {
132:     /* This is the RHS part */
133:     for (f = 0; f < Nf; f++) {
134:       PetscObject  obj;
135:       PetscClassId id;

137:       PetscCall(DMGetField(plex, f, NULL, &obj));
138:       PetscCall(PetscObjectGetClassId(obj, &id));
139:       if (id == PETSCFV_CLASSID) {
140:         PetscCall(DMPlexGetGeometryFVM(plex, &faceGeometryFVM, NULL, NULL));
141:         break;
142:       }
143:     }
144:   }
145:   PetscCall(DMPlexInsertBoundaryValues(plex, PETSC_TRUE, locX, time, faceGeometryFVM, NULL, NULL));
146:   PetscCall(DMPlexInsertTimeDerivativeBoundaryValues(plex, PETSC_TRUE, locX_t, time, faceGeometryFVM, NULL, NULL));
147:   PetscCall(DMDestroy(&plex));
148:   PetscFunctionReturn(PETSC_SUCCESS);
149: }

151: /*@
152:   DMPlexTSComputeIFunctionFEM - Form the local residual `locF` from the local input `locX` using pointwise functions specified by the user

154:   Input Parameters:
155: + dm     - The mesh
156: . time   - The time
157: . locX   - Local solution
158: . locX_t - Local solution time derivative, or `NULL`
159: - user   - The user context

161:   Output Parameter:
162: . locF - Local output vector

164:   Level: developer

166: .seealso: [](ch_ts), `DMPLEX`, `TS`, `DMPlexTSComputeRHSFunctionFEM()`
167: @*/
168: PetscErrorCode DMPlexTSComputeIFunctionFEM(DM dm, PetscReal time, Vec locX, Vec locX_t, Vec locF, void *user)
169: {
170:   DM       plex;
171:   IS       allcellIS;
172:   PetscInt Nds, s;

174:   PetscFunctionBegin;
175:   PetscCall(DMTSConvertPlex(dm, &plex, PETSC_TRUE));
176:   PetscCall(DMPlexGetAllCells_Internal(plex, &allcellIS));
177:   PetscCall(DMGetNumDS(dm, &Nds));
178:   for (s = 0; s < Nds; ++s) {
179:     PetscDS      ds;
180:     IS           cellIS;
181:     PetscFormKey key;

183:     PetscCall(DMGetRegionNumDS(dm, s, &key.label, NULL, &ds, NULL));
184:     key.value = 0;
185:     key.field = 0;
186:     key.part  = 0;
187:     if (!key.label) {
188:       PetscCall(PetscObjectReference((PetscObject)allcellIS));
189:       cellIS = allcellIS;
190:     } else {
191:       IS pointIS;

193:       key.value = 1;
194:       PetscCall(DMLabelGetStratumIS(key.label, key.value, &pointIS));
195:       PetscCall(ISIntersect_Caching_Internal(allcellIS, pointIS, &cellIS));
196:       PetscCall(ISDestroy(&pointIS));
197:     }
198:     PetscCall(DMPlexComputeResidual_Internal(plex, key, cellIS, time, locX, locX_t, time, locF, user));
199:     PetscCall(ISDestroy(&cellIS));
200:   }
201:   PetscCall(ISDestroy(&allcellIS));
202:   PetscCall(DMDestroy(&plex));
203:   PetscFunctionReturn(PETSC_SUCCESS);
204: }

206: /*@
207:   DMPlexTSComputeIJacobianFEM - Form the Jacobian `Jac` from the local input `locX` using pointwise functions specified by the user

209:   Input Parameters:
210: + dm       - The mesh
211: . time     - The time
212: . locX     - Local solution
213: . locX_t   - Local solution time derivative, or `NULL`
214: . X_tShift - The multiplicative parameter for dF/du_t
215: - user     - The user context

217:   Output Parameters:
218: + Jac  - the Jacobian
219: - JacP - an additional approximation for the Jacobian to be used to compute the preconditioner (often is `Jac`)

221:   Level: developer

223: .seealso: [](ch_ts), `TS`, `DM`, `DMPlexTSComputeIFunctionFEM()`, `DMPlexTSComputeRHSFunctionFEM()`
224: @*/
225: PetscErrorCode DMPlexTSComputeIJacobianFEM(DM dm, PetscReal time, Vec locX, Vec locX_t, PetscReal X_tShift, Mat Jac, Mat JacP, void *user)
226: {
227:   DM        plex;
228:   IS        allcellIS;
229:   PetscBool hasJac, hasPrec;
230:   PetscInt  Nds, s;

232:   PetscFunctionBegin;
233:   PetscCall(DMTSConvertPlex(dm, &plex, PETSC_TRUE));
234:   PetscCall(DMPlexGetAllCells_Internal(plex, &allcellIS));
235:   PetscCall(DMGetNumDS(dm, &Nds));
236:   for (s = 0; s < Nds; ++s) {
237:     PetscDS      ds;
238:     IS           cellIS;
239:     PetscFormKey key;

241:     PetscCall(DMGetRegionNumDS(dm, s, &key.label, NULL, &ds, NULL));
242:     key.value = 0;
243:     key.field = 0;
244:     key.part  = 0;
245:     if (!key.label) {
246:       PetscCall(PetscObjectReference((PetscObject)allcellIS));
247:       cellIS = allcellIS;
248:     } else {
249:       IS pointIS;

251:       key.value = 1;
252:       PetscCall(DMLabelGetStratumIS(key.label, key.value, &pointIS));
253:       PetscCall(ISIntersect_Caching_Internal(allcellIS, pointIS, &cellIS));
254:       PetscCall(ISDestroy(&pointIS));
255:     }
256:     if (!s) {
257:       PetscCall(PetscDSHasJacobian(ds, &hasJac));
258:       PetscCall(PetscDSHasJacobianPreconditioner(ds, &hasPrec));
259:       if (hasJac && hasPrec) PetscCall(MatZeroEntries(Jac));
260:       PetscCall(MatZeroEntries(JacP));
261:     }
262:     PetscCall(DMPlexComputeJacobian_Internal(plex, key, cellIS, time, X_tShift, locX, locX_t, Jac, JacP, user));
263:     PetscCall(ISDestroy(&cellIS));
264:   }
265:   PetscCall(ISDestroy(&allcellIS));
266:   PetscCall(DMDestroy(&plex));
267:   PetscFunctionReturn(PETSC_SUCCESS);
268: }

270: /*@
271:   DMPlexTSComputeRHSFunctionFEM - Form the local residual `locG` from the local input `locX` using pointwise functions specified by the user

273:   Input Parameters:
274: + dm   - The mesh
275: . time - The time
276: . locX - Local solution
277: - user - The user context

279:   Output Parameter:
280: . locG - Local output vector

282:   Level: developer

284: .seealso: [](ch_ts), `TS`, `DM`, `DMPlexTSComputeIFunctionFEM()`, `DMPlexTSComputeIJacobianFEM()`
285: @*/
286: PetscErrorCode DMPlexTSComputeRHSFunctionFEM(DM dm, PetscReal time, Vec locX, Vec locG, void *user)
287: {
288:   DM       plex;
289:   IS       allcellIS;
290:   PetscInt Nds, s;

292:   PetscFunctionBegin;
293:   PetscCall(DMTSConvertPlex(dm, &plex, PETSC_TRUE));
294:   PetscCall(DMPlexGetAllCells_Internal(plex, &allcellIS));
295:   PetscCall(DMGetNumDS(dm, &Nds));
296:   for (s = 0; s < Nds; ++s) {
297:     PetscDS      ds;
298:     IS           cellIS;
299:     PetscFormKey key;

301:     PetscCall(DMGetRegionNumDS(dm, s, &key.label, NULL, &ds, NULL));
302:     key.value = 0;
303:     key.field = 0;
304:     key.part  = 100;
305:     if (!key.label) {
306:       PetscCall(PetscObjectReference((PetscObject)allcellIS));
307:       cellIS = allcellIS;
308:     } else {
309:       IS pointIS;

311:       key.value = 1;
312:       PetscCall(DMLabelGetStratumIS(key.label, key.value, &pointIS));
313:       PetscCall(ISIntersect_Caching_Internal(allcellIS, pointIS, &cellIS));
314:       PetscCall(ISDestroy(&pointIS));
315:     }
316:     PetscCall(DMPlexComputeResidual_Internal(plex, key, cellIS, time, locX, NULL, time, locG, user));
317:     PetscCall(ISDestroy(&cellIS));
318:   }
319:   PetscCall(ISDestroy(&allcellIS));
320:   PetscCall(DMDestroy(&plex));
321:   PetscFunctionReturn(PETSC_SUCCESS);
322: }

324: /*@
325:   DMTSCheckResidual - Check the residual of the exact solution

327:   Input Parameters:
328: + ts  - the `TS` object
329: . dm  - the `DM`
330: . t   - the time
331: . u   - a `DM` vector
332: . u_t - a `DM` vector
333: - tol - A tolerance for the check, or -1 to print the results instead

335:   Output Parameter:
336: . residual - The residual norm of the exact solution, or `NULL`

338:   Level: developer

340: .seealso: [](ch_ts), `DM`, `DMTSCheckFromOptions()`, `DMTSCheckJacobian()`, `DNSNESCheckFromOptions()`, `DMSNESCheckDiscretization()`, `DMSNESCheckJacobian()`
341: @*/
342: PetscErrorCode DMTSCheckResidual(TS ts, DM dm, PetscReal t, Vec u, Vec u_t, PetscReal tol, PetscReal *residual)
343: {
344:   MPI_Comm  comm;
345:   Vec       r;
346:   PetscReal res;

348:   PetscFunctionBegin;
352:   if (residual) PetscAssertPointer(residual, 7);
353:   PetscCall(PetscObjectGetComm((PetscObject)ts, &comm));
354:   PetscCall(DMComputeExactSolution(dm, t, u, u_t));
355:   PetscCall(VecDuplicate(u, &r));
356:   PetscCall(TSComputeIFunction(ts, t, u, u_t, r, PETSC_FALSE));
357:   PetscCall(VecNorm(r, NORM_2, &res));
358:   if (tol >= 0.0) {
359:     PetscCheck(res <= tol, comm, PETSC_ERR_ARG_WRONG, "L_2 Residual %g exceeds tolerance %g", (double)res, (double)tol);
360:   } else if (residual) {
361:     *residual = res;
362:   } else {
363:     PetscCall(PetscPrintf(comm, "L_2 Residual: %g\n", (double)res));
364:     PetscCall(VecFilter(r, 1.0e-10));
365:     PetscCall(PetscObjectCompose((PetscObject)r, "__Vec_bc_zero__", (PetscObject)dm));
366:     PetscCall(PetscObjectSetName((PetscObject)r, "Initial Residual"));
367:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)r, "res_"));
368:     PetscCall(VecViewFromOptions(r, NULL, "-vec_view"));
369:     PetscCall(PetscObjectCompose((PetscObject)r, "__Vec_bc_zero__", NULL));
370:   }
371:   PetscCall(VecDestroy(&r));
372:   PetscFunctionReturn(PETSC_SUCCESS);
373: }

375: /*@
376:   DMTSCheckJacobian - Check the Jacobian of the exact solution against the residual using the Taylor Test

378:   Input Parameters:
379: + ts  - the `TS` object
380: . dm  - the `DM`
381: . t   - the time
382: . u   - a `DM` vector
383: . u_t - a `DM` vector
384: - tol - A tolerance for the check, or -1 to print the results instead

386:   Output Parameters:
387: + isLinear - Flag indicaing that the function looks linear, or `NULL`
388: - convRate - The rate of convergence of the linear model, or `NULL`

390:   Level: developer

392: .seealso: [](ch_ts), `DNTSCheckFromOptions()`, `DMTSCheckResidual()`, `DNSNESCheckFromOptions()`, `DMSNESCheckDiscretization()`, `DMSNESCheckResidual()`
393: @*/
394: PetscErrorCode DMTSCheckJacobian(TS ts, DM dm, PetscReal t, Vec u, Vec u_t, PetscReal tol, PetscBool *isLinear, PetscReal *convRate)
395: {
396:   MPI_Comm     comm;
397:   PetscDS      ds;
398:   Mat          J, M;
399:   MatNullSpace nullspace;
400:   PetscReal    dt, shift, slope, intercept;
401:   PetscBool    hasJac, hasPrec, isLin = PETSC_FALSE;

403:   PetscFunctionBegin;
407:   if (isLinear) PetscAssertPointer(isLinear, 7);
408:   if (convRate) PetscAssertPointer(convRate, 8);
409:   PetscCall(PetscObjectGetComm((PetscObject)ts, &comm));
410:   PetscCall(DMComputeExactSolution(dm, t, u, u_t));
411:   /* Create and view matrices */
412:   PetscCall(TSGetTimeStep(ts, &dt));
413:   shift = 1.0 / dt;
414:   PetscCall(DMCreateMatrix(dm, &J));
415:   PetscCall(DMGetDS(dm, &ds));
416:   PetscCall(PetscDSHasJacobian(ds, &hasJac));
417:   PetscCall(PetscDSHasJacobianPreconditioner(ds, &hasPrec));
418:   if (hasJac && hasPrec) {
419:     PetscCall(DMCreateMatrix(dm, &M));
420:     PetscCall(TSComputeIJacobian(ts, t, u, u_t, shift, J, M, PETSC_FALSE));
421:     PetscCall(PetscObjectSetName((PetscObject)M, "Preconditioning Matrix"));
422:     PetscCall(PetscObjectSetOptionsPrefix((PetscObject)M, "jacpre_"));
423:     PetscCall(MatViewFromOptions(M, NULL, "-mat_view"));
424:     PetscCall(MatDestroy(&M));
425:   } else {
426:     PetscCall(TSComputeIJacobian(ts, t, u, u_t, shift, J, J, PETSC_FALSE));
427:   }
428:   PetscCall(PetscObjectSetName((PetscObject)J, "Jacobian"));
429:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)J, "jac_"));
430:   PetscCall(MatViewFromOptions(J, NULL, "-mat_view"));
431:   /* Check nullspace */
432:   PetscCall(MatGetNullSpace(J, &nullspace));
433:   if (nullspace) {
434:     PetscBool isNull;
435:     PetscCall(MatNullSpaceTest(nullspace, J, &isNull));
436:     PetscCheck(isNull, comm, PETSC_ERR_PLIB, "The null space calculated for the system operator is invalid.");
437:   }
438:   /* Taylor test */
439:   {
440:     PetscRandom rand;
441:     Vec         du, uhat, uhat_t, r, rhat, df;
442:     PetscReal   h;
443:     PetscReal  *es, *hs, *errors;
444:     PetscReal   hMax = 1.0, hMin = 1e-6, hMult = 0.1;
445:     PetscInt    Nv, v;

447:     /* Choose a perturbation direction */
448:     PetscCall(PetscRandomCreate(comm, &rand));
449:     PetscCall(VecDuplicate(u, &du));
450:     PetscCall(VecSetRandom(du, rand));
451:     PetscCall(PetscRandomDestroy(&rand));
452:     PetscCall(VecDuplicate(u, &df));
453:     PetscCall(MatMult(J, du, df));
454:     /* Evaluate residual at u, F(u), save in vector r */
455:     PetscCall(VecDuplicate(u, &r));
456:     PetscCall(TSComputeIFunction(ts, t, u, u_t, r, PETSC_FALSE));
457:     /* Look at the convergence of our Taylor approximation as we approach u */
458:     for (h = hMax, Nv = 0; h >= hMin; h *= hMult, ++Nv);
459:     PetscCall(PetscCalloc3(Nv, &es, Nv, &hs, Nv, &errors));
460:     PetscCall(VecDuplicate(u, &uhat));
461:     PetscCall(VecDuplicate(u, &uhat_t));
462:     PetscCall(VecDuplicate(u, &rhat));
463:     for (h = hMax, Nv = 0; h >= hMin; h *= hMult, ++Nv) {
464:       PetscCall(VecWAXPY(uhat, h, du, u));
465:       PetscCall(VecWAXPY(uhat_t, h * shift, du, u_t));
466:       /* F(\hat u, \hat u_t) \approx F(u, u_t) + J(u, u_t) (uhat - u) + J_t(u, u_t) (uhat_t - u_t) = F(u) + h * J(u) du + h * shift * J_t(u) du = F(u) + h F' du */
467:       PetscCall(TSComputeIFunction(ts, t, uhat, uhat_t, rhat, PETSC_FALSE));
468:       PetscCall(VecAXPBYPCZ(rhat, -1.0, -h, 1.0, r, df));
469:       PetscCall(VecNorm(rhat, NORM_2, &errors[Nv]));

471:       es[Nv] = PetscLog10Real(errors[Nv]);
472:       hs[Nv] = PetscLog10Real(h);
473:     }
474:     PetscCall(VecDestroy(&uhat));
475:     PetscCall(VecDestroy(&uhat_t));
476:     PetscCall(VecDestroy(&rhat));
477:     PetscCall(VecDestroy(&df));
478:     PetscCall(VecDestroy(&r));
479:     PetscCall(VecDestroy(&du));
480:     for (v = 0; v < Nv; ++v) {
481:       if ((tol >= 0) && (errors[v] > tol)) break;
482:       else if (errors[v] > PETSC_SMALL) break;
483:     }
484:     if (v == Nv) isLin = PETSC_TRUE;
485:     PetscCall(PetscLinearRegression(Nv, hs, es, &slope, &intercept));
486:     PetscCall(PetscFree3(es, hs, errors));
487:     /* Slope should be about 2 */
488:     if (tol >= 0) {
489:       PetscCheck(isLin || PetscAbsReal(2 - slope) <= tol, comm, PETSC_ERR_ARG_WRONG, "Taylor approximation convergence rate should be 2, not %0.2f", (double)slope);
490:     } else if (isLinear || convRate) {
491:       if (isLinear) *isLinear = isLin;
492:       if (convRate) *convRate = slope;
493:     } else {
494:       if (!isLin) PetscCall(PetscPrintf(comm, "Taylor approximation converging at order %3.2f\n", (double)slope));
495:       else PetscCall(PetscPrintf(comm, "Function appears to be linear\n"));
496:     }
497:   }
498:   PetscCall(MatDestroy(&J));
499:   PetscFunctionReturn(PETSC_SUCCESS);
500: }

502: /*@C
503:   DMTSCheckFromOptions - Check the residual and Jacobian functions using the exact solution by outputting some diagnostic information based on
504:   values in the options database

506:   Input Parameters:
507: + ts - the `TS` object
508: - u  - representative `TS` vector

510:   Level: developer

512:   Note:
513:   The user must call `PetscDSSetExactSolution()` beforehand

515:   Developer Notes:
516:   What is the purpose of `u`, does it need to already have a solution or some other value in it?

518: .seealso: `DMTS`
519: @*/
520: PetscErrorCode DMTSCheckFromOptions(TS ts, Vec u)
521: {
522:   DM        dm;
523:   SNES      snes;
524:   Vec       sol, u_t;
525:   PetscReal t;
526:   PetscBool check;

528:   PetscFunctionBegin;
529:   PetscCall(PetscOptionsHasName(((PetscObject)ts)->options, ((PetscObject)ts)->prefix, "-dmts_check", &check));
530:   if (!check) PetscFunctionReturn(PETSC_SUCCESS);
531:   PetscCall(VecDuplicate(u, &sol));
532:   PetscCall(VecCopy(u, sol));
533:   PetscCall(TSSetSolution(ts, u));
534:   PetscCall(TSGetDM(ts, &dm));
535:   PetscCall(TSSetUp(ts));
536:   PetscCall(TSGetSNES(ts, &snes));
537:   PetscCall(SNESSetSolution(snes, u));

539:   PetscCall(TSGetTime(ts, &t));
540:   PetscCall(DMSNESCheckDiscretization(snes, dm, t, sol, -1.0, NULL));
541:   PetscCall(DMGetGlobalVector(dm, &u_t));
542:   PetscCall(DMTSCheckResidual(ts, dm, t, sol, u_t, -1.0, NULL));
543:   PetscCall(DMTSCheckJacobian(ts, dm, t, sol, u_t, -1.0, NULL, NULL));
544:   PetscCall(DMRestoreGlobalVector(dm, &u_t));

546:   PetscCall(VecDestroy(&sol));
547:   PetscFunctionReturn(PETSC_SUCCESS);
548: }