Actual source code: tsadapt.c

  1: #include <petsc/private/tsimpl.h>

  3: PetscClassId TSADAPT_CLASSID;

  5: static PetscFunctionList TSAdaptList;
  6: static PetscBool         TSAdaptPackageInitialized;
  7: static PetscBool         TSAdaptRegisterAllCalled;

  9: PETSC_EXTERN PetscErrorCode TSAdaptCreate_None(TSAdapt);
 10: PETSC_EXTERN PetscErrorCode TSAdaptCreate_Basic(TSAdapt);
 11: PETSC_EXTERN PetscErrorCode TSAdaptCreate_DSP(TSAdapt);
 12: PETSC_EXTERN PetscErrorCode TSAdaptCreate_CFL(TSAdapt);
 13: PETSC_EXTERN PetscErrorCode TSAdaptCreate_GLEE(TSAdapt);
 14: PETSC_EXTERN PetscErrorCode TSAdaptCreate_History(TSAdapt);

 16: /*@C
 17:   TSAdaptRegister -  adds a TSAdapt implementation

 19:   Not Collective, No Fortran Support

 21:   Input Parameters:
 22: + sname    - name of user-defined adaptivity scheme
 23: - function - routine to create method context

 25:   Level: advanced

 27:   Notes:
 28:   `TSAdaptRegister()` may be called multiple times to add several user-defined families.

 30:   Example Usage:
 31: .vb
 32:    TSAdaptRegister("my_scheme", MySchemeCreate);
 33: .ve

 35:   Then, your scheme can be chosen with the procedural interface via
 36: $     TSAdaptSetType(ts, "my_scheme")
 37:   or at runtime via the option
 38: $     -ts_adapt_type my_scheme

 40: .seealso: [](ch_ts), `TSAdaptRegisterAll()`
 41: @*/
 42: PetscErrorCode TSAdaptRegister(const char sname[], PetscErrorCode (*function)(TSAdapt))
 43: {
 44:   PetscFunctionBegin;
 45:   PetscCall(TSAdaptInitializePackage());
 46:   PetscCall(PetscFunctionListAdd(&TSAdaptList, sname, function));
 47:   PetscFunctionReturn(PETSC_SUCCESS);
 48: }

 50: /*@C
 51:   TSAdaptRegisterAll - Registers all of the adaptivity schemes in `TSAdapt`

 53:   Not Collective

 55:   Level: advanced

 57: .seealso: [](ch_ts), `TSAdaptRegisterDestroy()`
 58: @*/
 59: PetscErrorCode TSAdaptRegisterAll(void)
 60: {
 61:   PetscFunctionBegin;
 62:   if (TSAdaptRegisterAllCalled) PetscFunctionReturn(PETSC_SUCCESS);
 63:   TSAdaptRegisterAllCalled = PETSC_TRUE;
 64:   PetscCall(TSAdaptRegister(TSADAPTNONE, TSAdaptCreate_None));
 65:   PetscCall(TSAdaptRegister(TSADAPTBASIC, TSAdaptCreate_Basic));
 66:   PetscCall(TSAdaptRegister(TSADAPTDSP, TSAdaptCreate_DSP));
 67:   PetscCall(TSAdaptRegister(TSADAPTCFL, TSAdaptCreate_CFL));
 68:   PetscCall(TSAdaptRegister(TSADAPTGLEE, TSAdaptCreate_GLEE));
 69:   PetscCall(TSAdaptRegister(TSADAPTHISTORY, TSAdaptCreate_History));
 70:   PetscFunctionReturn(PETSC_SUCCESS);
 71: }

 73: /*@C
 74:   TSAdaptFinalizePackage - This function destroys everything in the `TS` package. It is
 75:   called from `PetscFinalize()`.

 77:   Level: developer

 79: .seealso: [](ch_ts), `PetscFinalize()`
 80: @*/
 81: PetscErrorCode TSAdaptFinalizePackage(void)
 82: {
 83:   PetscFunctionBegin;
 84:   PetscCall(PetscFunctionListDestroy(&TSAdaptList));
 85:   TSAdaptPackageInitialized = PETSC_FALSE;
 86:   TSAdaptRegisterAllCalled  = PETSC_FALSE;
 87:   PetscFunctionReturn(PETSC_SUCCESS);
 88: }

 90: /*@C
 91:   TSAdaptInitializePackage - This function initializes everything in the `TSAdapt` package. It is
 92:   called from `TSInitializePackage()`.

 94:   Level: developer

 96: .seealso: [](ch_ts), `PetscInitialize()`
 97: @*/
 98: PetscErrorCode TSAdaptInitializePackage(void)
 99: {
100:   PetscFunctionBegin;
101:   if (TSAdaptPackageInitialized) PetscFunctionReturn(PETSC_SUCCESS);
102:   TSAdaptPackageInitialized = PETSC_TRUE;
103:   PetscCall(PetscClassIdRegister("TSAdapt", &TSADAPT_CLASSID));
104:   PetscCall(TSAdaptRegisterAll());
105:   PetscCall(PetscRegisterFinalize(TSAdaptFinalizePackage));
106:   PetscFunctionReturn(PETSC_SUCCESS);
107: }

109: /*@
110:   TSAdaptSetType - sets the approach used for the error adapter

112:   Logicially Collective

114:   Input Parameters:
115: + adapt - the `TS` adapter, most likely obtained with `TSGetAdapt()`
116: - type  - one of the `TSAdaptType`

118:   Options Database Key:
119: . -ts_adapt_type <basic or dsp or none> - to set the adapter type

121:   Level: intermediate

123: .seealso: [](ch_ts), `TSGetAdapt()`, `TSAdaptDestroy()`, `TSAdaptType`, `TSAdaptGetType()`
124: @*/
125: PetscErrorCode TSAdaptSetType(TSAdapt adapt, TSAdaptType type)
126: {
127:   PetscBool match;
128:   PetscErrorCode (*r)(TSAdapt);

130:   PetscFunctionBegin;
132:   PetscAssertPointer(type, 2);
133:   PetscCall(PetscObjectTypeCompare((PetscObject)adapt, type, &match));
134:   if (match) PetscFunctionReturn(PETSC_SUCCESS);
135:   PetscCall(PetscFunctionListFind(TSAdaptList, type, &r));
136:   PetscCheck(r, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown TSAdapt type \"%s\" given", type);
137:   PetscTryTypeMethod(adapt, destroy);
138:   PetscCall(PetscMemzero(adapt->ops, sizeof(struct _TSAdaptOps)));
139:   PetscCall(PetscObjectChangeTypeName((PetscObject)adapt, type));
140:   PetscCall((*r)(adapt));
141:   PetscFunctionReturn(PETSC_SUCCESS);
142: }

144: /*@
145:   TSAdaptGetType - gets the `TS` adapter method type (as a string).

147:   Not Collective

149:   Input Parameter:
150: . adapt - The `TS` adapter, most likely obtained with `TSGetAdapt()`

152:   Output Parameter:
153: . type - The name of `TS` adapter method

155:   Level: intermediate

157: .seealso: `TSAdapt`, `TSAdaptType`, `TSAdaptSetType()`
158: @*/
159: PetscErrorCode TSAdaptGetType(TSAdapt adapt, TSAdaptType *type)
160: {
161:   PetscFunctionBegin;
163:   PetscAssertPointer(type, 2);
164:   *type = ((PetscObject)adapt)->type_name;
165:   PetscFunctionReturn(PETSC_SUCCESS);
166: }

168: PetscErrorCode TSAdaptSetOptionsPrefix(TSAdapt adapt, const char prefix[])
169: {
170:   PetscFunctionBegin;
172:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)adapt, prefix));
173:   PetscFunctionReturn(PETSC_SUCCESS);
174: }

176: /*@
177:   TSAdaptLoad - Loads a TSAdapt that has been stored in binary with `TSAdaptView()`.

179:   Collective

181:   Input Parameters:
182: + adapt  - the newly loaded `TSAdapt`, this needs to have been created with `TSAdaptCreate()` or
183:            some related function before a call to `TSAdaptLoad()`.
184: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()` or
185:            HDF5 file viewer, obtained from `PetscViewerHDF5Open()`

187:   Level: intermediate

189:   Note:
190:   The type is determined by the data in the file, any type set into the `TSAdapt` before this call is ignored.

192: .seealso: [](ch_ts), `PetscViewerBinaryOpen()`, `TSAdaptView()`, `MatLoad()`, `VecLoad()`, `TSAdapt`
193: @*/
194: PetscErrorCode TSAdaptLoad(TSAdapt adapt, PetscViewer viewer)
195: {
196:   PetscBool isbinary;
197:   char      type[256];

199:   PetscFunctionBegin;
202:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
203:   PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");

205:   PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
206:   PetscCall(TSAdaptSetType(adapt, type));
207:   PetscTryTypeMethod(adapt, load, viewer);
208:   PetscFunctionReturn(PETSC_SUCCESS);
209: }

211: PetscErrorCode TSAdaptView(TSAdapt adapt, PetscViewer viewer)
212: {
213:   PetscBool iascii, isbinary, isnone, isglee;

215:   PetscFunctionBegin;
217:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)adapt), &viewer));
219:   PetscCheckSameComm(adapt, 1, viewer, 2);
220:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
221:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
222:   if (iascii) {
223:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)adapt, viewer));
224:     PetscCall(PetscObjectTypeCompare((PetscObject)adapt, TSADAPTNONE, &isnone));
225:     PetscCall(PetscObjectTypeCompare((PetscObject)adapt, TSADAPTGLEE, &isglee));
226:     if (!isnone) {
227:       if (adapt->always_accept) PetscCall(PetscViewerASCIIPrintf(viewer, "  always accepting steps\n"));
228:       PetscCall(PetscViewerASCIIPrintf(viewer, "  safety factor %g\n", (double)adapt->safety));
229:       PetscCall(PetscViewerASCIIPrintf(viewer, "  extra safety factor after step rejection %g\n", (double)adapt->reject_safety));
230:       PetscCall(PetscViewerASCIIPrintf(viewer, "  clip fastest increase %g\n", (double)adapt->clip[1]));
231:       PetscCall(PetscViewerASCIIPrintf(viewer, "  clip fastest decrease %g\n", (double)adapt->clip[0]));
232:       PetscCall(PetscViewerASCIIPrintf(viewer, "  maximum allowed timestep %g\n", (double)adapt->dt_max));
233:       PetscCall(PetscViewerASCIIPrintf(viewer, "  minimum allowed timestep %g\n", (double)adapt->dt_min));
234:       PetscCall(PetscViewerASCIIPrintf(viewer, "  maximum solution absolute value to be ignored %g\n", (double)adapt->ignore_max));
235:     }
236:     if (isglee) {
237:       if (adapt->glee_use_local) {
238:         PetscCall(PetscViewerASCIIPrintf(viewer, "  GLEE uses local error control\n"));
239:       } else {
240:         PetscCall(PetscViewerASCIIPrintf(viewer, "  GLEE uses global error control\n"));
241:       }
242:     }
243:     PetscCall(PetscViewerASCIIPushTab(viewer));
244:     PetscTryTypeMethod(adapt, view, viewer);
245:     PetscCall(PetscViewerASCIIPopTab(viewer));
246:   } else if (isbinary) {
247:     char type[256];

249:     /* need to save FILE_CLASS_ID for adapt class */
250:     PetscCall(PetscStrncpy(type, ((PetscObject)adapt)->type_name, 256));
251:     PetscCall(PetscViewerBinaryWrite(viewer, type, 256, PETSC_CHAR));
252:   } else PetscTryTypeMethod(adapt, view, viewer);
253:   PetscFunctionReturn(PETSC_SUCCESS);
254: }

256: /*@
257:   TSAdaptReset - Resets a `TSAdapt` context to its defaults

259:   Collective

261:   Input Parameter:
262: . adapt - the `TSAdapt` context obtained from `TSGetAdapt()` or `TSAdaptCreate()`

264:   Level: developer

266: .seealso: [](ch_ts), `TSGetAdapt()`, `TSAdapt`, `TSAdaptCreate()`, `TSAdaptDestroy()`
267: @*/
268: PetscErrorCode TSAdaptReset(TSAdapt adapt)
269: {
270:   PetscFunctionBegin;
272:   PetscTryTypeMethod(adapt, reset);
273:   PetscFunctionReturn(PETSC_SUCCESS);
274: }

276: PetscErrorCode TSAdaptDestroy(TSAdapt *adapt)
277: {
278:   PetscFunctionBegin;
279:   if (!*adapt) PetscFunctionReturn(PETSC_SUCCESS);
281:   if (--((PetscObject)*adapt)->refct > 0) {
282:     *adapt = NULL;
283:     PetscFunctionReturn(PETSC_SUCCESS);
284:   }

286:   PetscCall(TSAdaptReset(*adapt));

288:   PetscTryTypeMethod(*adapt, destroy);
289:   PetscCall(PetscViewerDestroy(&(*adapt)->monitor));
290:   PetscCall(PetscHeaderDestroy(adapt));
291:   PetscFunctionReturn(PETSC_SUCCESS);
292: }

294: /*@
295:   TSAdaptSetMonitor - Monitor the choices made by the adaptive controller

297:   Collective

299:   Input Parameters:
300: + adapt - adaptive controller context
301: - flg   - `PETSC_TRUE` to active a monitor, `PETSC_FALSE` to disable

303:   Options Database Key:
304: . -ts_adapt_monitor - to turn on monitoring

306:   Level: intermediate

308: .seealso: [](ch_ts), `TSAdapt`, `TSGetAdapt()`, `TSAdaptChoose()`
309: @*/
310: PetscErrorCode TSAdaptSetMonitor(TSAdapt adapt, PetscBool flg)
311: {
312:   PetscFunctionBegin;
315:   if (flg) {
316:     if (!adapt->monitor) PetscCall(PetscViewerASCIIOpen(PetscObjectComm((PetscObject)adapt), "stdout", &adapt->monitor));
317:   } else {
318:     PetscCall(PetscViewerDestroy(&adapt->monitor));
319:   }
320:   PetscFunctionReturn(PETSC_SUCCESS);
321: }

323: /*@C
324:   TSAdaptSetCheckStage - Set a callback to check convergence for a stage

326:   Logically Collective

328:   Input Parameters:
329: + adapt - adaptive controller context
330: - func  - stage check function

332:   Calling sequence:
333: + adapt  - adaptive controller context
334: . ts     - time stepping context
335: . t      - current time
336: . Y      - current solution vector
337: - accept - pending choice of whether to accept, can be modified by this routine

339:   Level: advanced

341: .seealso: [](ch_ts), `TSAdapt`, `TSGetAdapt()`, `TSAdaptChoose()`
342: @*/
343: PetscErrorCode TSAdaptSetCheckStage(TSAdapt adapt, PetscErrorCode (*func)(TSAdapt adapt, TS ts, PetscReal t, Vec Y, PetscBool *accept))
344: {
345:   PetscFunctionBegin;
347:   adapt->checkstage = func;
348:   PetscFunctionReturn(PETSC_SUCCESS);
349: }

351: /*@
352:   TSAdaptSetAlwaysAccept - Set whether to always accept steps regardless of
353:   any error or stability condition not meeting the prescribed goal.

355:   Logically Collective

357:   Input Parameters:
358: + adapt - time step adaptivity context, usually gotten with `TSGetAdapt()`
359: - flag  - whether to always accept steps

361:   Options Database Key:
362: . -ts_adapt_always_accept - to always accept steps

364:   Level: intermediate

366: .seealso: [](ch_ts), `TSAdapt`, `TSGetAdapt()`, `TSAdaptChoose()`
367: @*/
368: PetscErrorCode TSAdaptSetAlwaysAccept(TSAdapt adapt, PetscBool flag)
369: {
370:   PetscFunctionBegin;
373:   adapt->always_accept = flag;
374:   PetscFunctionReturn(PETSC_SUCCESS);
375: }

377: /*@
378:   TSAdaptSetSafety - Set safety factors for time step adaptor

380:   Logically Collective

382:   Input Parameters:
383: + adapt         - adaptive controller context
384: . safety        - safety factor relative to target error/stability goal
385: - reject_safety - extra safety factor to apply if the last step was rejected

387:   Options Database Keys:
388: + -ts_adapt_safety <safety>               - to set safety factor
389: - -ts_adapt_reject_safety <reject_safety> - to set reject safety factor

391:   Level: intermediate

393:   Note:
394:   Use `PETSC_CURRENT` to keep the current value for either parameter

396:   Fortran Note:
397:   Use `PETSC_CURRENT_REAL`

399: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptGetSafety()`, `TSAdaptChoose()`
400: @*/
401: PetscErrorCode TSAdaptSetSafety(TSAdapt adapt, PetscReal safety, PetscReal reject_safety)
402: {
403:   PetscFunctionBegin;
407:   PetscCheck(safety == (PetscReal)PETSC_CURRENT || safety >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Safety factor %g must be non negative", (double)safety);
408:   PetscCheck(safety == (PetscReal)PETSC_CURRENT || safety <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Safety factor %g must be less than one", (double)safety);
409:   PetscCheck(reject_safety == (PetscReal)PETSC_CURRENT || reject_safety >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Reject safety factor %g must be non negative", (double)reject_safety);
410:   PetscCheck(reject_safety == (PetscReal)PETSC_CURRENT || reject_safety <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Reject safety factor %g must be less than one", (double)reject_safety);
411:   if (safety != (PetscReal)PETSC_CURRENT) adapt->safety = safety;
412:   if (reject_safety != (PetscReal)PETSC_CURRENT) adapt->reject_safety = reject_safety;
413:   PetscFunctionReturn(PETSC_SUCCESS);
414: }

416: /*@
417:   TSAdaptGetSafety - Get safety factors for time step adapter

419:   Not Collective

421:   Input Parameter:
422: . adapt - adaptive controller context

424:   Output Parameters:
425: + safety        - safety factor relative to target error/stability goal
426: - reject_safety - extra safety factor to apply if the last step was rejected

428:   Level: intermediate

430: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptSetSafety()`, `TSAdaptChoose()`
431: @*/
432: PetscErrorCode TSAdaptGetSafety(TSAdapt adapt, PetscReal *safety, PetscReal *reject_safety)
433: {
434:   PetscFunctionBegin;
436:   if (safety) PetscAssertPointer(safety, 2);
437:   if (reject_safety) PetscAssertPointer(reject_safety, 3);
438:   if (safety) *safety = adapt->safety;
439:   if (reject_safety) *reject_safety = adapt->reject_safety;
440:   PetscFunctionReturn(PETSC_SUCCESS);
441: }

443: /*@
444:   TSAdaptSetMaxIgnore - Set error estimation threshold. Solution components below this threshold value will not be considered when computing error norms
445:   for time step adaptivity (in absolute value). A negative value (default) of the threshold leads to considering all solution components.

447:   Logically Collective

449:   Input Parameters:
450: + adapt      - adaptive controller context
451: - max_ignore - threshold for solution components that are ignored during error estimation

453:   Options Database Key:
454: . -ts_adapt_max_ignore <max_ignore> - to set the threshold

456:   Level: intermediate

458: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptGetMaxIgnore()`, `TSAdaptChoose()`
459: @*/
460: PetscErrorCode TSAdaptSetMaxIgnore(TSAdapt adapt, PetscReal max_ignore)
461: {
462:   PetscFunctionBegin;
465:   adapt->ignore_max = max_ignore;
466:   PetscFunctionReturn(PETSC_SUCCESS);
467: }

469: /*@
470:   TSAdaptGetMaxIgnore - Get error estimation threshold. Solution components below this threshold value will not be considered when computing error norms
471:   for time step adaptivity (in absolute value).

473:   Not Collective

475:   Input Parameter:
476: . adapt - adaptive controller context

478:   Output Parameter:
479: . max_ignore - threshold for solution components that are ignored during error estimation

481:   Level: intermediate

483: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptSetMaxIgnore()`, `TSAdaptChoose()`
484: @*/
485: PetscErrorCode TSAdaptGetMaxIgnore(TSAdapt adapt, PetscReal *max_ignore)
486: {
487:   PetscFunctionBegin;
489:   PetscAssertPointer(max_ignore, 2);
490:   *max_ignore = adapt->ignore_max;
491:   PetscFunctionReturn(PETSC_SUCCESS);
492: }

494: /*@
495:   TSAdaptSetClip - Sets the admissible decrease/increase factor in step size in the time step adapter

497:   Logically collective

499:   Input Parameters:
500: + adapt - adaptive controller context
501: . low   - admissible decrease factor
502: - high  - admissible increase factor

504:   Options Database Key:
505: . -ts_adapt_clip <low>,<high> - to set admissible time step decrease and increase factors

507:   Level: intermediate

509:   Note:
510:   Use `PETSC_CURRENT` to keep the current value for either parameter

512:   Fortran Note:
513:   Use `PETSC_CURRENT_REAL`

515: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptGetClip()`, `TSAdaptSetScaleSolveFailed()`
516: @*/
517: PetscErrorCode TSAdaptSetClip(TSAdapt adapt, PetscReal low, PetscReal high)
518: {
519:   PetscFunctionBegin;
523:   PetscCheck(low == (PetscReal)PETSC_CURRENT || low >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Decrease factor %g must be non negative", (double)low);
524:   PetscCheck(low == (PetscReal)PETSC_CURRENT || low <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Decrease factor %g must be less than one", (double)low);
525:   PetscCheck(high == (PetscReal)PETSC_CURRENT || high >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Increase factor %g must be greater than one", (double)high);
526:   if (low != (PetscReal)PETSC_CURRENT) adapt->clip[0] = low;
527:   if (high != (PetscReal)PETSC_CURRENT) adapt->clip[1] = high;
528:   PetscFunctionReturn(PETSC_SUCCESS);
529: }

531: /*@
532:   TSAdaptGetClip - Gets the admissible decrease/increase factor in step size in the time step adapter

534:   Not Collective

536:   Input Parameter:
537: . adapt - adaptive controller context

539:   Output Parameters:
540: + low  - optional, admissible decrease factor
541: - high - optional, admissible increase factor

543:   Level: intermediate

545: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptSetClip()`, `TSAdaptSetScaleSolveFailed()`
546: @*/
547: PetscErrorCode TSAdaptGetClip(TSAdapt adapt, PetscReal *low, PetscReal *high)
548: {
549:   PetscFunctionBegin;
551:   if (low) PetscAssertPointer(low, 2);
552:   if (high) PetscAssertPointer(high, 3);
553:   if (low) *low = adapt->clip[0];
554:   if (high) *high = adapt->clip[1];
555:   PetscFunctionReturn(PETSC_SUCCESS);
556: }

558: /*@
559:   TSAdaptSetScaleSolveFailed - Scale step size by this factor if solve fails

561:   Logically Collective

563:   Input Parameters:
564: + adapt - adaptive controller context
565: - scale - scale

567:   Options Database Key:
568: . -ts_adapt_scale_solve_failed <scale> - to set scale step by this factor if solve fails

570:   Level: intermediate

572: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptGetScaleSolveFailed()`, `TSAdaptGetClip()`
573: @*/
574: PetscErrorCode TSAdaptSetScaleSolveFailed(TSAdapt adapt, PetscReal scale)
575: {
576:   PetscFunctionBegin;
579:   PetscCheck(scale > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Scale factor %g must be positive", (double)scale);
580:   PetscCheck(scale <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Scale factor %g must be less than one", (double)scale);
581:   adapt->scale_solve_failed = scale;
582:   PetscFunctionReturn(PETSC_SUCCESS);
583: }

585: /*@
586:   TSAdaptGetScaleSolveFailed - Gets the admissible decrease/increase factor in step size

588:   Not Collective

590:   Input Parameter:
591: . adapt - adaptive controller context

593:   Output Parameter:
594: . scale - scale factor

596:   Level: intermediate

598: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptSetScaleSolveFailed()`, `TSAdaptSetClip()`
599: @*/
600: PetscErrorCode TSAdaptGetScaleSolveFailed(TSAdapt adapt, PetscReal *scale)
601: {
602:   PetscFunctionBegin;
604:   if (scale) PetscAssertPointer(scale, 2);
605:   if (scale) *scale = adapt->scale_solve_failed;
606:   PetscFunctionReturn(PETSC_SUCCESS);
607: }

609: /*@
610:   TSAdaptSetStepLimits - Set the minimum and maximum step sizes to be considered by the time step controller

612:   Logically Collective

614:   Input Parameters:
615: + adapt - time step adaptivity context, usually gotten with `TSGetAdapt()`
616: . hmin  - minimum time step
617: - hmax  - maximum time step

619:   Options Database Keys:
620: + -ts_adapt_dt_min <min> - to set minimum time step
621: - -ts_adapt_dt_max <max> - to set maximum time step

623:   Level: intermediate

625:   Note:
626:   Use `PETSC_CURRENT` to keep the current value for either parameter

628:   Fortran Note:
629:   Use `PETSC_CURRENT_REAL`

631: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptGetStepLimits()`, `TSAdaptChoose()`
632: @*/
633: PetscErrorCode TSAdaptSetStepLimits(TSAdapt adapt, PetscReal hmin, PetscReal hmax)
634: {
635:   PetscFunctionBegin;
639:   PetscCheck(hmin == (PetscReal)PETSC_CURRENT || hmin >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Minimum time step %g must be non negative", (double)hmin);
640:   PetscCheck(hmax == (PetscReal)PETSC_CURRENT || hmax >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Minimum time step %g must be non negative", (double)hmax);
641:   if (hmin != (PetscReal)PETSC_CURRENT) adapt->dt_min = hmin;
642:   if (hmax != (PetscReal)PETSC_CURRENT) adapt->dt_max = hmax;
643:   hmin = adapt->dt_min;
644:   hmax = adapt->dt_max;
645:   PetscCheck(hmax > hmin, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Maximum time step %g must greater than minimum time step %g", (double)hmax, (double)hmin);
646:   PetscFunctionReturn(PETSC_SUCCESS);
647: }

649: /*@
650:   TSAdaptGetStepLimits - Get the minimum and maximum step sizes to be considered by the time step controller

652:   Not Collective

654:   Input Parameter:
655: . adapt - time step adaptivity context, usually gotten with `TSGetAdapt()`

657:   Output Parameters:
658: + hmin - minimum time step
659: - hmax - maximum time step

661:   Level: intermediate

663: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptSetStepLimits()`, `TSAdaptChoose()`
664: @*/
665: PetscErrorCode TSAdaptGetStepLimits(TSAdapt adapt, PetscReal *hmin, PetscReal *hmax)
666: {
667:   PetscFunctionBegin;
669:   if (hmin) PetscAssertPointer(hmin, 2);
670:   if (hmax) PetscAssertPointer(hmax, 3);
671:   if (hmin) *hmin = adapt->dt_min;
672:   if (hmax) *hmax = adapt->dt_max;
673:   PetscFunctionReturn(PETSC_SUCCESS);
674: }

676: /*@C
677:   TSAdaptSetFromOptions - Sets various `TSAdapt` parameters from user options.

679:   Collective

681:   Input Parameters:
682: + adapt              - the `TSAdapt` context
683: - PetscOptionsObject - object created by `PetscOptionsBegin()`

685:   Options Database Keys:
686: + -ts_adapt_type <type>                - algorithm to use for adaptivity
687: . -ts_adapt_always_accept              - always accept steps regardless of error/stability goals
688: . -ts_adapt_safety <safety>            - safety factor relative to target error/stability goal
689: . -ts_adapt_reject_safety <safety>     - extra safety factor to apply if the last step was rejected
690: . -ts_adapt_clip <low,high>            - admissible time step decrease and increase factors
691: . -ts_adapt_dt_min <min>               - minimum timestep to use
692: . -ts_adapt_dt_max <max>               - maximum timestep to use
693: . -ts_adapt_scale_solve_failed <scale> - scale timestep by this factor if a solve fails
694: . -ts_adapt_wnormtype <2 or infinity>  - type of norm for computing error estimates
695: - -ts_adapt_time_step_increase_delay   - number of timesteps to delay increasing the time step after it has been decreased due to failed solver

697:   Level: advanced

699:   Note:
700:   This function is automatically called by `TSSetFromOptions()`

702: .seealso: [](ch_ts), `TSAdapt`, `TSGetAdapt()`, `TSAdaptSetType()`, `TSAdaptSetAlwaysAccept()`, `TSAdaptSetSafety()`,
703:           `TSAdaptSetClip()`, `TSAdaptSetScaleSolveFailed()`, `TSAdaptSetStepLimits()`, `TSAdaptSetMonitor()`
704: @*/
705: PetscErrorCode TSAdaptSetFromOptions(TSAdapt adapt, PetscOptionItems *PetscOptionsObject)
706: {
707:   char      type[256] = TSADAPTBASIC;
708:   PetscReal safety, reject_safety, clip[2], scale, hmin, hmax;
709:   PetscBool set, flg;
710:   PetscInt  two;

712:   PetscFunctionBegin;
714:   /* This should use PetscOptionsBegin() if/when this becomes an object used outside of TS, but currently this
715:    * function can only be called from inside TSSetFromOptions()  */
716:   PetscOptionsHeadBegin(PetscOptionsObject, "TS Adaptivity options");
717:   PetscCall(PetscOptionsFList("-ts_adapt_type", "Algorithm to use for adaptivity", "TSAdaptSetType", TSAdaptList, ((PetscObject)adapt)->type_name ? ((PetscObject)adapt)->type_name : type, type, sizeof(type), &flg));
718:   if (flg || !((PetscObject)adapt)->type_name) PetscCall(TSAdaptSetType(adapt, type));

720:   PetscCall(PetscOptionsBool("-ts_adapt_always_accept", "Always accept the step", "TSAdaptSetAlwaysAccept", adapt->always_accept, &flg, &set));
721:   if (set) PetscCall(TSAdaptSetAlwaysAccept(adapt, flg));

723:   safety        = adapt->safety;
724:   reject_safety = adapt->reject_safety;
725:   PetscCall(PetscOptionsReal("-ts_adapt_safety", "Safety factor relative to target error/stability goal", "TSAdaptSetSafety", safety, &safety, &set));
726:   PetscCall(PetscOptionsReal("-ts_adapt_reject_safety", "Extra safety factor to apply if the last step was rejected", "TSAdaptSetSafety", reject_safety, &reject_safety, &flg));
727:   if (set || flg) PetscCall(TSAdaptSetSafety(adapt, safety, reject_safety));

729:   two     = 2;
730:   clip[0] = adapt->clip[0];
731:   clip[1] = adapt->clip[1];
732:   PetscCall(PetscOptionsRealArray("-ts_adapt_clip", "Admissible decrease/increase factor in step size", "TSAdaptSetClip", clip, &two, &set));
733:   PetscCheck(!set || (two == 2), PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_OUTOFRANGE, "Must give exactly two values to -ts_adapt_clip");
734:   if (set) PetscCall(TSAdaptSetClip(adapt, clip[0], clip[1]));

736:   hmin = adapt->dt_min;
737:   hmax = adapt->dt_max;
738:   PetscCall(PetscOptionsReal("-ts_adapt_dt_min", "Minimum time step considered", "TSAdaptSetStepLimits", hmin, &hmin, &set));
739:   PetscCall(PetscOptionsReal("-ts_adapt_dt_max", "Maximum time step considered", "TSAdaptSetStepLimits", hmax, &hmax, &flg));
740:   if (set || flg) PetscCall(TSAdaptSetStepLimits(adapt, hmin, hmax));

742:   PetscCall(PetscOptionsReal("-ts_adapt_max_ignore", "Adaptor ignores (absolute) solution values smaller than this value", "", adapt->ignore_max, &adapt->ignore_max, &set));
743:   PetscCall(PetscOptionsBool("-ts_adapt_glee_use_local", "GLEE adaptor uses local error estimation for step control", "", adapt->glee_use_local, &adapt->glee_use_local, &set));

745:   PetscCall(PetscOptionsReal("-ts_adapt_scale_solve_failed", "Scale step by this factor if solve fails", "TSAdaptSetScaleSolveFailed", adapt->scale_solve_failed, &scale, &set));
746:   if (set) PetscCall(TSAdaptSetScaleSolveFailed(adapt, scale));

748:   PetscCall(PetscOptionsEnum("-ts_adapt_wnormtype", "Type of norm computed for error estimation", "", NormTypes, (PetscEnum)adapt->wnormtype, (PetscEnum *)&adapt->wnormtype, NULL));
749:   PetscCheck(adapt->wnormtype == NORM_2 || adapt->wnormtype == NORM_INFINITY, PetscObjectComm((PetscObject)adapt), PETSC_ERR_SUP, "Only 2-norm and infinite norm supported");

751:   PetscCall(PetscOptionsInt("-ts_adapt_time_step_increase_delay", "Number of timesteps to delay increasing the time step after it has been decreased due to failed solver", "TSAdaptSetTimeStepIncreaseDelay", adapt->timestepjustdecreased_delay, &adapt->timestepjustdecreased_delay, NULL));

753:   PetscCall(PetscOptionsBool("-ts_adapt_monitor", "Print choices made by adaptive controller", "TSAdaptSetMonitor", adapt->monitor ? PETSC_TRUE : PETSC_FALSE, &flg, &set));
754:   if (set) PetscCall(TSAdaptSetMonitor(adapt, flg));

756:   PetscTryTypeMethod(adapt, setfromoptions, PetscOptionsObject);
757:   PetscOptionsHeadEnd();
758:   PetscFunctionReturn(PETSC_SUCCESS);
759: }

761: /*@
762:   TSAdaptCandidatesClear - clear any previously set candidate schemes

764:   Logically Collective

766:   Input Parameter:
767: . adapt - adaptive controller

769:   Level: developer

771: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptCreate()`, `TSAdaptCandidateAdd()`, `TSAdaptChoose()`
772: @*/
773: PetscErrorCode TSAdaptCandidatesClear(TSAdapt adapt)
774: {
775:   PetscFunctionBegin;
777:   PetscCall(PetscMemzero(&adapt->candidates, sizeof(adapt->candidates)));
778:   PetscFunctionReturn(PETSC_SUCCESS);
779: }

781: /*@C
782:   TSAdaptCandidateAdd - add a candidate scheme for the adaptive controller to select from

784:   Logically Collective; No Fortran Support

786:   Input Parameters:
787: + adapt      - time step adaptivity context, obtained with `TSGetAdapt()` or `TSAdaptCreate()`
788: . name       - name of the candidate scheme to add
789: . order      - order of the candidate scheme
790: . stageorder - stage order of the candidate scheme
791: . ccfl       - stability coefficient relative to explicit Euler, used for CFL constraints
792: . cost       - relative measure of the amount of work required for the candidate scheme
793: - inuse      - indicates that this scheme is the one currently in use, this flag can only be set for one scheme

795:   Level: developer

797: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptCandidatesClear()`, `TSAdaptChoose()`
798: @*/
799: PetscErrorCode TSAdaptCandidateAdd(TSAdapt adapt, const char name[], PetscInt order, PetscInt stageorder, PetscReal ccfl, PetscReal cost, PetscBool inuse)
800: {
801:   PetscInt c;

803:   PetscFunctionBegin;
805:   PetscCheck(order >= 1, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_OUTOFRANGE, "Classical order %" PetscInt_FMT " must be a positive integer", order);
806:   if (inuse) {
807:     PetscCheck(!adapt->candidates.inuse_set, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_WRONGSTATE, "Cannot set the inuse method twice, maybe forgot to call TSAdaptCandidatesClear()");
808:     adapt->candidates.inuse_set = PETSC_TRUE;
809:   }
810:   /* first slot if this is the current scheme, otherwise the next available slot */
811:   c = inuse ? 0 : !adapt->candidates.inuse_set + adapt->candidates.n;

813:   adapt->candidates.name[c]       = name;
814:   adapt->candidates.order[c]      = order;
815:   adapt->candidates.stageorder[c] = stageorder;
816:   adapt->candidates.ccfl[c]       = ccfl;
817:   adapt->candidates.cost[c]       = cost;
818:   adapt->candidates.n++;
819:   PetscFunctionReturn(PETSC_SUCCESS);
820: }

822: /*@C
823:   TSAdaptCandidatesGet - Get the list of candidate orders of accuracy and cost

825:   Not Collective

827:   Input Parameter:
828: . adapt - time step adaptivity context

830:   Output Parameters:
831: + n          - number of candidate schemes, always at least 1
832: . order      - the order of each candidate scheme
833: . stageorder - the stage order of each candidate scheme
834: . ccfl       - the CFL coefficient of each scheme
835: - cost       - the relative cost of each scheme

837:   Level: developer

839:   Note:
840:   The current scheme is always returned in the first slot

842: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptCandidatesClear()`, `TSAdaptCandidateAdd()`, `TSAdaptChoose()`
843: @*/
844: PetscErrorCode TSAdaptCandidatesGet(TSAdapt adapt, PetscInt *n, const PetscInt **order, const PetscInt **stageorder, const PetscReal **ccfl, const PetscReal **cost)
845: {
846:   PetscFunctionBegin;
848:   if (n) *n = adapt->candidates.n;
849:   if (order) *order = adapt->candidates.order;
850:   if (stageorder) *stageorder = adapt->candidates.stageorder;
851:   if (ccfl) *ccfl = adapt->candidates.ccfl;
852:   if (cost) *cost = adapt->candidates.cost;
853:   PetscFunctionReturn(PETSC_SUCCESS);
854: }

856: /*@C
857:   TSAdaptChoose - choose which method and step size to use for the next step

859:   Collective

861:   Input Parameters:
862: + adapt - adaptive controller
863: . ts    - time stepper
864: - h     - current step size

866:   Output Parameters:
867: + next_sc - optional, scheme to use for the next step
868: . next_h  - step size to use for the next step
869: - accept  - `PETSC_TRUE` to accept the current step, `PETSC_FALSE` to repeat the current step with the new step size

871:   Level: developer

873:   Note:
874:   The input value of parameter accept is retained from the last time step, so it will be `PETSC_FALSE` if the step is
875:   being retried after an initial rejection.

877: .seealso: [](ch_ts), `TSAdapt`, `TSAdaptCandidatesClear()`, `TSAdaptCandidateAdd()`
878: @*/
879: PetscErrorCode TSAdaptChoose(TSAdapt adapt, TS ts, PetscReal h, PetscInt *next_sc, PetscReal *next_h, PetscBool *accept)
880: {
881:   PetscInt  ncandidates = adapt->candidates.n;
882:   PetscInt  scheme      = 0;
883:   PetscReal wlte        = -1.0;
884:   PetscReal wltea       = -1.0;
885:   PetscReal wlter       = -1.0;

887:   PetscFunctionBegin;
890:   if (next_sc) PetscAssertPointer(next_sc, 4);
891:   PetscAssertPointer(next_h, 5);
892:   PetscAssertPointer(accept, 6);
893:   if (next_sc) *next_sc = 0;

895:   /* Do not mess with adaptivity while handling events */
896:   if (ts->event && ts->event->processing) {
897:     *next_h = h;
898:     *accept = PETSC_TRUE;
899:     if (adapt->monitor) {
900:       PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));

902:       if (ts->event->iterctr == 0) {
903:         /*
904:           An event has been found, now finalising the event processing: performing the 1st and 2nd post-event steps.
905:           Entering this if-branch means both these steps (set to either PETSC_DECIDE or numerical value) are managed
906:           by the event handler. In this case the 1st post-event step is always accepted, without interference of TSAdapt.
907:           Note: if the 2nd post-event step is not managed by the event handler (e.g. given 1st = numerical, 2nd = PETSC_DECIDE),
908:           this if-branch is not entered, and TSAdapt may reject/adjust the proposed 1st post-event step.
909:         */
910:         PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "    TSAdapt does not interfere, step %3" PetscInt_FMT " accepted. Processing post-event steps: 1-st accepted just now, 2-nd yet to come\n", ts->steps));
911:       } else PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "    TSAdapt does not interfere, step %3" PetscInt_FMT " accepted. Event handling in progress\n", ts->steps));

913:       PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
914:     }
915:     PetscFunctionReturn(PETSC_SUCCESS);
916:   }

918:   PetscUseTypeMethod(adapt, choose, ts, h, &scheme, next_h, accept, &wlte, &wltea, &wlter);
919:   PetscCheck(scheme >= 0 && (ncandidates <= 0 || scheme < ncandidates), PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_OUTOFRANGE, "Chosen scheme %" PetscInt_FMT " not in valid range 0..%" PetscInt_FMT, scheme, ncandidates - 1);
920:   PetscCheck(*next_h >= 0, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_OUTOFRANGE, "Computed step size %g must be positive", (double)*next_h);
921:   if (next_sc) *next_sc = scheme;

923:   if (*accept && ts->exact_final_time == TS_EXACTFINALTIME_MATCHSTEP) {
924:     /* Increase/reduce step size if end time of next step is close to or overshoots max time */
925:     PetscReal t   = ts->ptime + ts->time_step, tend, tmax, h1, hmax;
926:     PetscReal a   = (PetscReal)(1.0 + adapt->matchstepfac[0]);
927:     PetscReal b   = adapt->matchstepfac[1];
928:     PetscReal eps = 10 * PETSC_MACHINE_EPSILON;

930:     /*
931:       Logic in using 'dt_span_cached':
932:       1. It always overrides *next_h, except (any of):
933:          a) the current step was rejected,
934:          b) the adaptor proposed to decrease the next step,
935:          c) the adaptor proposed *next_h > dt_span_cached.
936:       2. If *next_h was adjusted by tspan points (or the final point):
937:            -- when dt_span_cached is filled (>0), it keeps its value,
938:            -- when dt_span_cached is clear (==0), it gets the unadjusted version of *next_h.
939:       3. If *next_h was not adjusted as in (2), dt_span_cached is cleared.
940:       Note, if a combination (1.b || 1.c) && (3) takes place, this means that
941:       dt_span_cached remains unused at the moment of clearing.
942:       If (1.a) takes place, dt_span_cached keeps its value.
943:       Also, dt_span_cached can be updated by the event handler, see tsevent.c.
944:     */
945:     if (h <= *next_h && *next_h <= adapt->dt_span_cached) *next_h = adapt->dt_span_cached; /* try employing the cache */
946:     h1   = *next_h;
947:     tend = t + h1;

949:     if (ts->tspan && ts->tspan->spanctr < ts->tspan->num_span_times) {
950:       PetscCheck(ts->tspan->worktol == 0, PetscObjectComm((PetscObject)adapt), PETSC_ERR_PLIB, "Unexpected state (tspan->worktol != 0) in TSAdaptChoose()");
951:       ts->tspan->worktol = ts->tspan->reltol * h1 + ts->tspan->abstol;
952:       if (PetscIsCloseAtTol(t, ts->tspan->span_times[ts->tspan->spanctr], ts->tspan->worktol, 0)) /* hit a span time point */
953:         if (ts->tspan->spanctr + 1 < ts->tspan->num_span_times) tmax = ts->tspan->span_times[ts->tspan->spanctr + 1];
954:         else tmax = ts->max_time; /* hit the last span time point */
955:       else tmax = ts->tspan->span_times[ts->tspan->spanctr];
956:     } else tmax = ts->max_time;
957:     tmax = PetscMin(tmax, ts->max_time);
958:     hmax = tmax - t;
959:     PetscCheck((hmax > eps) || (PetscAbsReal(hmax) <= eps && PetscIsCloseAtTol(t, ts->max_time, eps, 0)), PetscObjectComm((PetscObject)adapt), PETSC_ERR_PLIB, "Unexpected state: bad hmax in TSAdaptChoose()");

961:     if (t < tmax && tend > tmax) *next_h = hmax;
962:     if (t < tmax && tend < tmax && h1 * b > hmax) *next_h = hmax / 2;
963:     if (t < tmax && tend < tmax && h1 * a > hmax) *next_h = hmax;
964:     if (ts->tspan && h1 != *next_h && !adapt->dt_span_cached) adapt->dt_span_cached = h1; /* cache the step size if it is to be changed    */
965:     if (ts->tspan && h1 == *next_h && adapt->dt_span_cached) adapt->dt_span_cached = 0;   /* clear the cache if the step size is unchanged */
966:   }
967:   if (adapt->monitor) {
968:     const char *sc_name = (scheme < ncandidates) ? adapt->candidates.name[scheme] : "";
969:     PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
970:     if (wlte < 0) {
971:       PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "    TSAdapt %s %s %" PetscInt_FMT ":%s step %3" PetscInt_FMT " %s t=%-11g+%10.3e dt=%-10.3e\n", ((PetscObject)adapt)->type_name, ((PetscObject)ts)->type_name, scheme, sc_name, ts->steps, *accept ? "accepted" : "rejected",
972:                                        (double)ts->ptime, (double)h, (double)*next_h));
973:     } else {
974:       PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "    TSAdapt %s %s %" PetscInt_FMT ":%s step %3" PetscInt_FMT " %s t=%-11g+%10.3e dt=%-10.3e wlte=%5.3g  wltea=%5.3g wlter=%5.3g\n", ((PetscObject)adapt)->type_name, ((PetscObject)ts)->type_name, scheme, sc_name, ts->steps, *accept ? "accepted" : "rejected",
975:                                        (double)ts->ptime, (double)h, (double)*next_h, (double)wlte, (double)wltea, (double)wlter));
976:     }
977:     PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
978:   }
979:   PetscFunctionReturn(PETSC_SUCCESS);
980: }

982: /*@
983:   TSAdaptSetTimeStepIncreaseDelay - The number of timesteps to wait after a decrease in the timestep due to failed solver
984:   before increasing the time step.

986:   Logicially Collective

988:   Input Parameters:
989: + adapt - adaptive controller context
990: - cnt   - the number of timesteps

992:   Options Database Key:
993: . -ts_adapt_time_step_increase_delay cnt - number of steps to delay the increase

995:   Level: advanced

997:   Notes:
998:   This is to prevent an adaptor from bouncing back and forth between two nearby timesteps. The default is 0.

1000:   The successful use of this option is problem dependent

1002:   Developer Notes:
1003:   There is no theory to support this option

1005: .seealso: [](ch_ts), `TSAdapt`
1006: @*/
1007: PetscErrorCode TSAdaptSetTimeStepIncreaseDelay(TSAdapt adapt, PetscInt cnt)
1008: {
1009:   PetscFunctionBegin;
1010:   adapt->timestepjustdecreased_delay = cnt;
1011:   PetscFunctionReturn(PETSC_SUCCESS);
1012: }

1014: /*@
1015:   TSAdaptCheckStage - checks whether to accept a stage, (e.g. reject and change time step size if nonlinear solve fails or solution vector is infeasible)

1017:   Collective

1019:   Input Parameters:
1020: + adapt - adaptive controller context
1021: . ts    - time stepper
1022: . t     - Current simulation time
1023: - Y     - Current solution vector

1025:   Output Parameter:
1026: . accept - `PETSC_TRUE` to accept the stage, `PETSC_FALSE` to reject

1028:   Level: developer

1030: .seealso: [](ch_ts), `TSAdapt`
1031: @*/
1032: PetscErrorCode TSAdaptCheckStage(TSAdapt adapt, TS ts, PetscReal t, Vec Y, PetscBool *accept)
1033: {
1034:   SNESConvergedReason snesreason = SNES_CONVERGED_ITERATING;
1035:   PetscBool           func_accept, snes_div_func;

1037:   PetscFunctionBegin;
1040:   PetscAssertPointer(accept, 5);

1042:   PetscCall(TSFunctionDomainError(ts, t, Y, &func_accept));
1043:   if (ts->snes) PetscCall(SNESGetConvergedReason(ts->snes, &snesreason));
1044:   snes_div_func = (PetscBool)(snesreason == SNES_DIVERGED_FUNCTION_DOMAIN);
1045:   if (func_accept && snesreason < 0 && !snes_div_func) {
1046:     *accept = PETSC_FALSE;
1047:     PetscCall(PetscInfo(ts, "Step=%" PetscInt_FMT ", nonlinear solve failure: %s\n", ts->steps, SNESConvergedReasons[snesreason]));
1048:     if (++ts->num_snes_failures >= ts->max_snes_failures && ts->max_snes_failures != PETSC_UNLIMITED) {
1049:       ts->reason = TS_DIVERGED_NONLINEAR_SOLVE;
1050:       PetscCall(PetscInfo(ts, "Step=%" PetscInt_FMT ", nonlinear solve failures %" PetscInt_FMT " greater than current TS allowed, stopping solve\n", ts->steps, ts->num_snes_failures));
1051:       if (adapt->monitor) {
1052:         PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1053:         PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "    TSAdapt %s step %3" PetscInt_FMT " stage rejected t=%-11g+%10.3e, nonlinear solve failures %" PetscInt_FMT " greater than current TS allowed\n", ((PetscObject)adapt)->type_name, ts->steps,
1054:                                          (double)ts->ptime, (double)ts->time_step, ts->num_snes_failures));
1055:         PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1056:       }
1057:     }
1058:   } else {
1059:     *accept = (PetscBool)(func_accept && !snes_div_func);
1060:     if (*accept && adapt->checkstage) PetscCall((*adapt->checkstage)(adapt, ts, t, Y, accept));
1061:     if (!*accept) {
1062:       const char *user_func = !func_accept ? "TSSetFunctionDomainError()" : "TSAdaptSetCheckStage";
1063:       const char *snes_err  = "SNES invalid function domain";
1064:       const char *err_msg   = snes_div_func && func_accept ? snes_err : user_func;
1065:       PetscCall(PetscInfo(ts, "Step=%" PetscInt_FMT ", solution rejected by %s\n", ts->steps, err_msg));
1066:       if (adapt->monitor) {
1067:         PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1068:         PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "    TSAdapt %s step %3" PetscInt_FMT " stage rejected by %s\n", ((PetscObject)adapt)->type_name, ts->steps, err_msg));
1069:         PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1070:       }
1071:     }
1072:   }

1074:   if (!*accept && !ts->reason) {
1075:     PetscReal dt, new_dt;
1076:     PetscCall(TSGetTimeStep(ts, &dt));
1077:     new_dt = dt * adapt->scale_solve_failed;
1078:     PetscCall(TSSetTimeStep(ts, new_dt));
1079:     adapt->timestepjustdecreased += adapt->timestepjustdecreased_delay;
1080:     if (adapt->monitor) {
1081:       PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1082:       PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "    TSAdapt %s step %3" PetscInt_FMT " stage rejected (SNES reason %s) t=%-11g+%10.3e retrying with dt=%-10.3e\n", ((PetscObject)adapt)->type_name, ts->steps, SNESConvergedReasons[snesreason],
1083:                                        (double)ts->ptime, (double)dt, (double)new_dt));
1084:       PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1085:     }
1086:   }
1087:   PetscFunctionReturn(PETSC_SUCCESS);
1088: }

1090: /*@
1091:   TSAdaptCreate - create an adaptive controller context for time stepping

1093:   Collective

1095:   Input Parameter:
1096: . comm - The communicator

1098:   Output Parameter:
1099: . inadapt - new `TSAdapt` object

1101:   Level: developer

1103:   Note:
1104:   `TSAdapt` creation is handled by `TS`, so users should not need to call this function.

1106: .seealso: [](ch_ts), `TSAdapt`, `TSGetAdapt()`, `TSAdaptSetType()`, `TSAdaptDestroy()`
1107: @*/
1108: PetscErrorCode TSAdaptCreate(MPI_Comm comm, TSAdapt *inadapt)
1109: {
1110:   TSAdapt adapt;

1112:   PetscFunctionBegin;
1113:   PetscAssertPointer(inadapt, 2);
1114:   PetscCall(TSAdaptInitializePackage());

1116:   PetscCall(PetscHeaderCreate(adapt, TSADAPT_CLASSID, "TSAdapt", "Time stepping adaptivity", "TS", comm, TSAdaptDestroy, TSAdaptView));
1117:   adapt->always_accept      = PETSC_FALSE;
1118:   adapt->safety             = 0.9;
1119:   adapt->reject_safety      = 0.5;
1120:   adapt->clip[0]            = 0.1;
1121:   adapt->clip[1]            = 10.;
1122:   adapt->dt_min             = 1e-20;
1123:   adapt->dt_max             = 1e+20;
1124:   adapt->ignore_max         = -1.0;
1125:   adapt->glee_use_local     = PETSC_TRUE;
1126:   adapt->scale_solve_failed = 0.25;
1127:   /* these two safety factors are not public, and they are used only in the TS_EXACTFINALTIME_MATCHSTEP case
1128:      to prevent from situations were unreasonably small time steps are taken in order to match the final time */
1129:   adapt->matchstepfac[0]             = 0.01; /* allow 1% step size increase in the last step */
1130:   adapt->matchstepfac[1]             = 2.0;  /* halve last step if it is greater than what remains divided this factor */
1131:   adapt->wnormtype                   = NORM_2;
1132:   adapt->timestepjustdecreased_delay = 0;
1133:   *inadapt                           = adapt;
1134:   PetscFunctionReturn(PETSC_SUCCESS);
1135: }