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: .vb
 37:   TSAdaptSetType(ts, "my_scheme")
 38: .ve
 39:   or at runtime via the option
 40: .vb
 41:   -ts_adapt_type my_scheme
 42: .ve

 44: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdaptRegisterAll()`
 45: @*/
 46: PetscErrorCode TSAdaptRegister(const char sname[], PetscErrorCode (*function)(TSAdapt))
 47: {
 48:   PetscFunctionBegin;
 49:   PetscCall(TSAdaptInitializePackage());
 50:   PetscCall(PetscFunctionListAdd(&TSAdaptList, sname, function));
 51:   PetscFunctionReturn(PETSC_SUCCESS);
 52: }

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

 57:   Not Collective

 59:   Level: advanced

 61: .seealso: [](ch_ts), `TSAdaptRegisterDestroy()`
 62: @*/
 63: PetscErrorCode TSAdaptRegisterAll(void)
 64: {
 65:   PetscFunctionBegin;
 66:   if (TSAdaptRegisterAllCalled) PetscFunctionReturn(PETSC_SUCCESS);
 67:   TSAdaptRegisterAllCalled = PETSC_TRUE;
 68:   PetscCall(TSAdaptRegister(TSADAPTNONE, TSAdaptCreate_None));
 69:   PetscCall(TSAdaptRegister(TSADAPTBASIC, TSAdaptCreate_Basic));
 70:   PetscCall(TSAdaptRegister(TSADAPTDSP, TSAdaptCreate_DSP));
 71:   PetscCall(TSAdaptRegister(TSADAPTCFL, TSAdaptCreate_CFL));
 72:   PetscCall(TSAdaptRegister(TSADAPTGLEE, TSAdaptCreate_GLEE));
 73:   PetscCall(TSAdaptRegister(TSADAPTHISTORY, TSAdaptCreate_History));
 74:   PetscFunctionReturn(PETSC_SUCCESS);
 75: }

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

 81:   Level: developer

 83: .seealso: [](ch_ts), `PetscFinalize()`
 84: @*/
 85: PetscErrorCode TSAdaptFinalizePackage(void)
 86: {
 87:   PetscFunctionBegin;
 88:   PetscCall(PetscFunctionListDestroy(&TSAdaptList));
 89:   TSAdaptPackageInitialized = PETSC_FALSE;
 90:   TSAdaptRegisterAllCalled  = PETSC_FALSE;
 91:   PetscFunctionReturn(PETSC_SUCCESS);
 92: }

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

 98:   Level: developer

100: .seealso: [](ch_ts), `PetscInitialize()`
101: @*/
102: PetscErrorCode TSAdaptInitializePackage(void)
103: {
104:   PetscFunctionBegin;
105:   if (TSAdaptPackageInitialized) PetscFunctionReturn(PETSC_SUCCESS);
106:   TSAdaptPackageInitialized = PETSC_TRUE;
107:   PetscCall(PetscClassIdRegister("TSAdapt", &TSADAPT_CLASSID));
108:   PetscCall(TSAdaptRegisterAll());
109:   PetscCall(PetscRegisterFinalize(TSAdaptFinalizePackage));
110:   PetscFunctionReturn(PETSC_SUCCESS);
111: }

113: /*@
114:   TSAdaptSetType - sets the approach used for the error adapter

116:   Logicially Collective

118:   Input Parameters:
119: + adapt - the `TS` adapter, most likely obtained with `TSGetAdapt()`
120: - type  - one of the `TSAdaptType`

122:   Options Database Key:
123: . -ts_adapt_type (basic|dsp|none|cfl|glee|history) - to set the adapter type

125:   Level: intermediate

127: .seealso: [](ch_ts), [](sec_ts_error_control), `TSGetAdapt()`, `TSAdaptDestroy()`, `TSAdaptType`, `TSAdaptGetType()`
128: @*/
129: PetscErrorCode TSAdaptSetType(TSAdapt adapt, TSAdaptType type)
130: {
131:   PetscBool match;
132:   PetscErrorCode (*r)(TSAdapt);

134:   PetscFunctionBegin;
136:   PetscAssertPointer(type, 2);
137:   PetscCall(PetscObjectTypeCompare((PetscObject)adapt, type, &match));
138:   if (match) PetscFunctionReturn(PETSC_SUCCESS);
139:   PetscCall(PetscFunctionListFind(TSAdaptList, type, &r));
140:   PetscCheck(r, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unknown TSAdapt type \"%s\" given", type);
141:   PetscTryTypeMethod(adapt, destroy);
142:   PetscCall(PetscMemzero(adapt->ops, sizeof(struct _TSAdaptOps)));
143:   PetscCall(PetscObjectChangeTypeName((PetscObject)adapt, type));
144:   PetscCall((*r)(adapt));
145:   PetscFunctionReturn(PETSC_SUCCESS);
146: }

148: /*@
149:   TSAdaptGetType - gets the `TS` adapter method type (as a string).

151:   Not Collective

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

156:   Output Parameter:
157: . type - The name of `TS` adapter method

159:   Level: intermediate

161: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptType`, `TSAdaptSetType()`
162: @*/
163: PetscErrorCode TSAdaptGetType(TSAdapt adapt, TSAdaptType *type)
164: {
165:   PetscFunctionBegin;
167:   PetscAssertPointer(type, 2);
168:   *type = ((PetscObject)adapt)->type_name;
169:   PetscFunctionReturn(PETSC_SUCCESS);
170: }

172: /*@C
173:   TSAdaptSetOptionsPrefix - Sets the prefix used for searching for `TSAdapt` options in the options database

175:   Logically Collective

177:   Input Parameters:
178: + adapt  - the `TSAdapt` context, most likely obtained with `TSGetAdapt()`
179: - prefix - the prefix to prepend to all option names

181:   Level: advanced

183: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSGetAdapt()`, `TSSetOptionsPrefix()`
184: @*/
185: PetscErrorCode TSAdaptSetOptionsPrefix(TSAdapt adapt, const char prefix[])
186: {
187:   PetscFunctionBegin;
189:   PetscCall(PetscObjectSetOptionsPrefix((PetscObject)adapt, prefix));
190:   PetscFunctionReturn(PETSC_SUCCESS);
191: }

193: /*@
194:   TSAdaptLoad - Loads a TSAdapt that has been stored in binary with `TSAdaptView()`.

196:   Collective

198:   Input Parameters:
199: + adapt  - the newly loaded `TSAdapt`, this needs to have been created with `TSAdaptCreate()` or
200:            some related function before a call to `TSAdaptLoad()`.
201: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()` or
202:            HDF5 file viewer, obtained from `PetscViewerHDF5Open()`

204:   Level: intermediate

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

209: .seealso: [](ch_ts), `PetscViewerBinaryOpen()`, `TSAdaptView()`, `MatLoad()`, `VecLoad()`, `TSAdapt`
210: @*/
211: PetscErrorCode TSAdaptLoad(TSAdapt adapt, PetscViewer viewer)
212: {
213:   PetscBool isbinary;
214:   char      type[256];

216:   PetscFunctionBegin;
219:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
220:   PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");

222:   PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
223:   PetscCall(TSAdaptSetType(adapt, type));
224:   PetscTryTypeMethod(adapt, load, viewer);
225:   PetscFunctionReturn(PETSC_SUCCESS);
226: }

228: /*@
229:   TSAdaptView - Prints the `TSAdapt` data structure.

231:   Collective

233:   Input Parameters:
234: + adapt  - the `TSAdapt` context obtained from `TSGetAdapt()`
235: - viewer - visualization context

237:   Options Database Key:
238: . -ts_view - calls `TSView()` at end of `TSStep()`

240:   Level: advanced

242:   Notes:
243:   This is called by `TSView()` so rarely called directly.

245:   The available visualization contexts include
246: +     `PETSC_VIEWER_STDOUT_SELF` - standard output (default)
247: -     `PETSC_VIEWER_STDOUT_WORLD` - synchronized standard
248:   output where only the first processor opens
249:   the file. All other processes send their
250:   data to the first process to print.

252:   The user can open an alternative visualization context with
253:   `PetscViewerASCIIOpen()` - output to a specified file.

255:   In the debugger you can do call `TSAdaptView`(adapt,0) to display the `TSAdapt`. (The same holds for any PETSc object viewer).

257: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSView()`, `PetscViewer`, `PetscViewerASCIIOpen()`
258: @*/
259: PetscErrorCode TSAdaptView(TSAdapt adapt, PetscViewer viewer)
260: {
261:   PetscBool isascii, isbinary, isnone, isglee;

263:   PetscFunctionBegin;
265:   if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)adapt), &viewer));
267:   PetscCheckSameComm(adapt, 1, viewer, 2);
268:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
269:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
270:   if (isascii) {
271:     PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)adapt, viewer));
272:     PetscCall(PetscObjectTypeCompare((PetscObject)adapt, TSADAPTNONE, &isnone));
273:     PetscCall(PetscObjectTypeCompare((PetscObject)adapt, TSADAPTGLEE, &isglee));
274:     if (!isnone) {
275:       if (adapt->always_accept) PetscCall(PetscViewerASCIIPrintf(viewer, "  always accepting steps\n"));
276:       PetscCall(PetscViewerASCIIPrintf(viewer, "  safety factor %g\n", (double)adapt->safety));
277:       PetscCall(PetscViewerASCIIPrintf(viewer, "  extra safety factor after step rejection %g\n", (double)adapt->reject_safety));
278:       PetscCall(PetscViewerASCIIPrintf(viewer, "  clip fastest increase %g\n", (double)adapt->clip[1]));
279:       PetscCall(PetscViewerASCIIPrintf(viewer, "  clip fastest decrease %g\n", (double)adapt->clip[0]));
280:       PetscCall(PetscViewerASCIIPrintf(viewer, "  maximum allowed timestep %g\n", (double)adapt->dt_max));
281:       PetscCall(PetscViewerASCIIPrintf(viewer, "  minimum allowed timestep %g\n", (double)adapt->dt_min));
282:       PetscCall(PetscViewerASCIIPrintf(viewer, "  maximum solution absolute value to be ignored %g\n", (double)adapt->ignore_max));
283:     }
284:     if (isglee) {
285:       if (adapt->glee_use_local) {
286:         PetscCall(PetscViewerASCIIPrintf(viewer, "  GLEE uses local error control\n"));
287:       } else {
288:         PetscCall(PetscViewerASCIIPrintf(viewer, "  GLEE uses global error control\n"));
289:       }
290:     }
291:     PetscCall(PetscViewerASCIIPushTab(viewer));
292:     PetscTryTypeMethod(adapt, view, viewer);
293:     PetscCall(PetscViewerASCIIPopTab(viewer));
294:   } else if (isbinary) {
295:     char type[256];

297:     /* need to save FILE_CLASS_ID for adapt class */
298:     PetscCall(PetscStrncpy(type, ((PetscObject)adapt)->type_name, 256));
299:     PetscCall(PetscViewerBinaryWrite(viewer, type, 256, PETSC_CHAR));
300:   } else PetscTryTypeMethod(adapt, view, viewer);
301:   PetscFunctionReturn(PETSC_SUCCESS);
302: }

304: /*@
305:   TSAdaptReset - Resets a `TSAdapt` context to its defaults

307:   Collective

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

312:   Level: developer

314: .seealso: [](ch_ts), [](sec_ts_error_control), `TSGetAdapt()`, `TSAdapt`, `TSAdaptCreate()`, `TSAdaptDestroy()`
315: @*/
316: PetscErrorCode TSAdaptReset(TSAdapt adapt)
317: {
318:   PetscFunctionBegin;
320:   PetscTryTypeMethod(adapt, reset);
321:   PetscFunctionReturn(PETSC_SUCCESS);
322: }

324: /*@
325:   TSAdaptDestroy - Destroys a `TSAdapt` context

327:   Collective

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

332:   Level: intermediate

334: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptCreate()`, `TSGetAdapt()`
335: @*/
336: PetscErrorCode TSAdaptDestroy(TSAdapt *adapt)
337: {
338:   PetscFunctionBegin;
339:   if (!*adapt) PetscFunctionReturn(PETSC_SUCCESS);
341:   if (--((PetscObject)*adapt)->refct > 0) {
342:     *adapt = NULL;
343:     PetscFunctionReturn(PETSC_SUCCESS);
344:   }

346:   PetscCall(TSAdaptReset(*adapt));

348:   PetscTryTypeMethod(*adapt, destroy);
349:   PetscCall(PetscViewerDestroy(&(*adapt)->monitor));
350:   PetscCall(PetscHeaderDestroy(adapt));
351:   PetscFunctionReturn(PETSC_SUCCESS);
352: }

354: /*@
355:   TSAdaptSetMonitor - Monitor the choices made by the adaptive controller

357:   Collective

359:   Input Parameters:
360: + adapt - adaptive controller context
361: - flg   - `PETSC_TRUE` to active a monitor, `PETSC_FALSE` to disable

363:   Options Database Key:
364: . -ts_adapt_monitor - to turn on monitoring

366:   Level: intermediate

368: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSGetAdapt()`, `TSAdaptChoose()`
369: @*/
370: PetscErrorCode TSAdaptSetMonitor(TSAdapt adapt, PetscBool flg)
371: {
372:   PetscFunctionBegin;
375:   if (flg) {
376:     if (!adapt->monitor) PetscCall(PetscViewerASCIIOpen(PetscObjectComm((PetscObject)adapt), "stdout", &adapt->monitor));
377:   } else {
378:     PetscCall(PetscViewerDestroy(&adapt->monitor));
379:   }
380:   PetscFunctionReturn(PETSC_SUCCESS);
381: }

383: /*@C
384:   TSAdaptSetCheckStage - Set a callback to check convergence for a stage

386:   Logically Collective

388:   Input Parameters:
389: + adapt - adaptive controller context
390: - func  - stage check function

392:   Calling sequence:
393: + adapt  - adaptive controller context
394: . ts     - time stepping context
395: . t      - current time
396: . Y      - current solution vector
397: - accept - pending choice of whether to accept, can be modified by this routine

399:   Level: advanced

401: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSGetAdapt()`, `TSAdaptChoose()`
402: @*/
403: PetscErrorCode TSAdaptSetCheckStage(TSAdapt adapt, PetscErrorCode (*func)(TSAdapt adapt, TS ts, PetscReal t, Vec Y, PetscBool *accept))
404: {
405:   PetscFunctionBegin;
407:   adapt->checkstage = func;
408:   PetscFunctionReturn(PETSC_SUCCESS);
409: }

411: /*@
412:   TSAdaptSetAlwaysAccept - Set whether to always accept steps regardless of
413:   any error or stability condition not meeting the prescribed goal.

415:   Logically Collective

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

421:   Options Database Key:
422: . -ts_adapt_always_accept - to always accept steps

424:   Level: intermediate

426: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSGetAdapt()`, `TSAdaptChoose()`
427: @*/
428: PetscErrorCode TSAdaptSetAlwaysAccept(TSAdapt adapt, PetscBool flag)
429: {
430:   PetscFunctionBegin;
433:   adapt->always_accept = flag;
434:   PetscFunctionReturn(PETSC_SUCCESS);
435: }

437: /*@
438:   TSAdaptSetSafety - Set safety factors for time step adaptor

440:   Logically Collective

442:   Input Parameters:
443: + adapt         - adaptive controller context
444: . safety        - safety factor relative to target error/stability goal
445: - reject_safety - extra safety factor to apply if the last step was rejected

447:   Options Database Keys:
448: + -ts_adapt_safety safety               - to set safety factor
449: - -ts_adapt_reject_safety reject_safety - to set reject safety factor

451:   Level: intermediate

453:   Note:
454:   Use `PETSC_CURRENT` to keep the current value for either parameter

456:   Fortran Note:
457:   Use `PETSC_CURRENT_REAL`

459: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptGetSafety()`, `TSAdaptChoose()`
460: @*/
461: PetscErrorCode TSAdaptSetSafety(TSAdapt adapt, PetscReal safety, PetscReal reject_safety)
462: {
463:   PetscFunctionBegin;
467:   PetscCheck(safety == (PetscReal)PETSC_CURRENT || safety >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Safety factor %g must be non negative", (double)safety);
468:   PetscCheck(safety == (PetscReal)PETSC_CURRENT || safety <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Safety factor %g must be less than one", (double)safety);
469:   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);
470:   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);
471:   if (safety != (PetscReal)PETSC_CURRENT) adapt->safety = safety;
472:   if (reject_safety != (PetscReal)PETSC_CURRENT) adapt->reject_safety = reject_safety;
473:   PetscFunctionReturn(PETSC_SUCCESS);
474: }

476: /*@
477:   TSAdaptGetSafety - Get safety factors for time step adapter

479:   Not Collective

481:   Input Parameter:
482: . adapt - adaptive controller context

484:   Output Parameters:
485: + safety        - safety factor relative to target error/stability goal
486: - reject_safety - extra safety factor to apply if the last step was rejected

488:   Level: intermediate

490: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptSetSafety()`, `TSAdaptChoose()`
491: @*/
492: PetscErrorCode TSAdaptGetSafety(TSAdapt adapt, PetscReal *safety, PetscReal *reject_safety)
493: {
494:   PetscFunctionBegin;
496:   if (safety) PetscAssertPointer(safety, 2);
497:   if (reject_safety) PetscAssertPointer(reject_safety, 3);
498:   if (safety) *safety = adapt->safety;
499:   if (reject_safety) *reject_safety = adapt->reject_safety;
500:   PetscFunctionReturn(PETSC_SUCCESS);
501: }

503: /*@
504:   TSAdaptSetMaxIgnore - Set error estimation threshold. Solution components below this threshold value will not be considered when computing error norms
505:   for time step adaptivity (in absolute value). A negative value (default) of the threshold leads to considering all solution components.

507:   Logically Collective

509:   Input Parameters:
510: + adapt      - adaptive controller context
511: - max_ignore - threshold for solution components that are ignored during error estimation

513:   Options Database Key:
514: . -ts_adapt_max_ignore max_ignore - to set the threshold

516:   Level: intermediate

518: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptGetMaxIgnore()`, `TSAdaptChoose()`
519: @*/
520: PetscErrorCode TSAdaptSetMaxIgnore(TSAdapt adapt, PetscReal max_ignore)
521: {
522:   PetscFunctionBegin;
525:   adapt->ignore_max = max_ignore;
526:   PetscFunctionReturn(PETSC_SUCCESS);
527: }

529: /*@
530:   TSAdaptGetMaxIgnore - Get error estimation threshold. Solution components below this threshold value will not be considered when computing error norms
531:   for time step adaptivity (in absolute value).

533:   Not Collective

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

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

541:   Level: intermediate

543: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptSetMaxIgnore()`, `TSAdaptChoose()`
544: @*/
545: PetscErrorCode TSAdaptGetMaxIgnore(TSAdapt adapt, PetscReal *max_ignore)
546: {
547:   PetscFunctionBegin;
549:   PetscAssertPointer(max_ignore, 2);
550:   *max_ignore = adapt->ignore_max;
551:   PetscFunctionReturn(PETSC_SUCCESS);
552: }

554: /*@
555:   TSAdaptSetClip - Sets the admissible decrease/increase factor in step size in the time step adapter

557:   Logically collective

559:   Input Parameters:
560: + adapt - adaptive controller context
561: . low   - admissible decrease factor
562: - high  - admissible increase factor

564:   Options Database Key:
565: . -ts_adapt_clip low,high - to set admissible time step decrease and increase factors

567:   Level: intermediate

569:   Note:
570:   Use `PETSC_CURRENT` to keep the current value for either parameter

572:   Fortran Note:
573:   Use `PETSC_CURRENT_REAL`

575: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptGetClip()`, `TSAdaptSetScaleSolveFailed()`
576: @*/
577: PetscErrorCode TSAdaptSetClip(TSAdapt adapt, PetscReal low, PetscReal high)
578: {
579:   PetscFunctionBegin;
583:   PetscCheck(low == (PetscReal)PETSC_CURRENT || low >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Decrease factor %g must be non negative", (double)low);
584:   PetscCheck(low == (PetscReal)PETSC_CURRENT || low <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Decrease factor %g must be less than one", (double)low);
585:   PetscCheck(high == (PetscReal)PETSC_CURRENT || high >= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Increase factor %g must be greater than one", (double)high);
586:   if (low != (PetscReal)PETSC_CURRENT) adapt->clip[0] = low;
587:   if (high != (PetscReal)PETSC_CURRENT) adapt->clip[1] = high;
588:   PetscFunctionReturn(PETSC_SUCCESS);
589: }

591: /*@
592:   TSAdaptGetClip - Gets the admissible decrease/increase factor in step size in the time step adapter

594:   Not Collective

596:   Input Parameter:
597: . adapt - adaptive controller context

599:   Output Parameters:
600: + low  - optional, admissible decrease factor
601: - high - optional, admissible increase factor

603:   Level: intermediate

605: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptSetClip()`, `TSAdaptSetScaleSolveFailed()`
606: @*/
607: PetscErrorCode TSAdaptGetClip(TSAdapt adapt, PetscReal *low, PetscReal *high)
608: {
609:   PetscFunctionBegin;
611:   if (low) PetscAssertPointer(low, 2);
612:   if (high) PetscAssertPointer(high, 3);
613:   if (low) *low = adapt->clip[0];
614:   if (high) *high = adapt->clip[1];
615:   PetscFunctionReturn(PETSC_SUCCESS);
616: }

618: /*@
619:   TSAdaptSetScaleSolveFailed - Scale step size by this factor if solve fails

621:   Logically Collective

623:   Input Parameters:
624: + adapt - adaptive controller context
625: - scale - scale

627:   Options Database Key:
628: . -ts_adapt_scale_solve_failed scale - to set scale step by this factor if solve fails

630:   Level: intermediate

632: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptGetScaleSolveFailed()`, `TSAdaptGetClip()`
633: @*/
634: PetscErrorCode TSAdaptSetScaleSolveFailed(TSAdapt adapt, PetscReal scale)
635: {
636:   PetscFunctionBegin;
639:   PetscCheck(scale > 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Scale factor %g must be positive", (double)scale);
640:   PetscCheck(scale <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Scale factor %g must be less than one", (double)scale);
641:   adapt->scale_solve_failed = scale;
642:   PetscFunctionReturn(PETSC_SUCCESS);
643: }

645: /*@
646:   TSAdaptGetScaleSolveFailed - Gets the admissible decrease/increase factor in step size

648:   Not Collective

650:   Input Parameter:
651: . adapt - adaptive controller context

653:   Output Parameter:
654: . scale - scale factor

656:   Level: intermediate

658: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptChoose()`, `TSAdaptSetScaleSolveFailed()`, `TSAdaptSetClip()`
659: @*/
660: PetscErrorCode TSAdaptGetScaleSolveFailed(TSAdapt adapt, PetscReal *scale)
661: {
662:   PetscFunctionBegin;
664:   if (scale) PetscAssertPointer(scale, 2);
665:   if (scale) *scale = adapt->scale_solve_failed;
666:   PetscFunctionReturn(PETSC_SUCCESS);
667: }

669: /*@
670:   TSAdaptSetStepLimits - Set the minimum and maximum step sizes to be considered by the time step controller

672:   Logically Collective

674:   Input Parameters:
675: + adapt - time step adaptivity context, usually gotten with `TSGetAdapt()`
676: . hmin  - minimum time step
677: - hmax  - maximum time step

679:   Options Database Keys:
680: + -ts_adapt_dt_min min - to set minimum time step
681: - -ts_adapt_dt_max max - to set maximum time step

683:   Level: intermediate

685:   Note:
686:   Use `PETSC_CURRENT` to keep the current value for either parameter

688:   Fortran Note:
689:   Use `PETSC_CURRENT_REAL`

691: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptGetStepLimits()`, `TSAdaptChoose()`
692: @*/
693: PetscErrorCode TSAdaptSetStepLimits(TSAdapt adapt, PetscReal hmin, PetscReal hmax)
694: {
695:   PetscFunctionBegin;
699:   PetscCheck(hmin == (PetscReal)PETSC_CURRENT || hmin >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Minimum time step %g must be non negative", (double)hmin);
700:   PetscCheck(hmax == (PetscReal)PETSC_CURRENT || hmax >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Minimum time step %g must be non negative", (double)hmax);
701:   if (hmin != (PetscReal)PETSC_CURRENT) adapt->dt_min = hmin;
702:   if (hmax != (PetscReal)PETSC_CURRENT) adapt->dt_max = hmax;
703:   hmin = adapt->dt_min;
704:   hmax = adapt->dt_max;
705:   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);
706:   PetscFunctionReturn(PETSC_SUCCESS);
707: }

709: /*@
710:   TSAdaptGetStepLimits - Get the minimum and maximum step sizes to be considered by the time step controller

712:   Not Collective

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

717:   Output Parameters:
718: + hmin - minimum time step
719: - hmax - maximum time step

721:   Level: intermediate

723: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptSetStepLimits()`, `TSAdaptChoose()`
724: @*/
725: PetscErrorCode TSAdaptGetStepLimits(TSAdapt adapt, PetscReal *hmin, PetscReal *hmax)
726: {
727:   PetscFunctionBegin;
729:   if (hmin) PetscAssertPointer(hmin, 2);
730:   if (hmax) PetscAssertPointer(hmax, 3);
731:   if (hmin) *hmin = adapt->dt_min;
732:   if (hmax) *hmax = adapt->dt_max;
733:   PetscFunctionReturn(PETSC_SUCCESS);
734: }

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

739:   Collective

741:   Input Parameters:
742: + adapt              - the `TSAdapt` context
743: - PetscOptionsObject - object created by `PetscOptionsBegin()`

745:   Options Database Keys:
746: + -ts_adapt_type (basic|dsp|none|cfl|glee|history) - algorithm to use for adaptivity
747: . -ts_adapt_always_accept (true|false)             - always accept steps regardless of error/stability goals
748: . -ts_adapt_safety safety                          - safety factor relative to target error/stability goal
749: . -ts_adapt_reject_safety safety                   - extra safety factor to apply if the last step was rejected
750: . -ts_adapt_clip low,high                          - admissible time step decrease and increase factors
751: . -ts_adapt_dt_min min                             - minimum timestep to use
752: . -ts_adapt_dt_max max                             - maximum timestep to use
753: . -ts_adapt_scale_solve_failed scale               - scale timestep by this factor if a solve fails
754: . -ts_adapt_wnormtype (2|infinity)                 - type of norm for computing error estimates
755: - -ts_adapt_time_step_increase_delay steps         - number of timesteps to delay increasing the time step after it has been decreased due to failed solver

757:   Level: advanced

759:   Note:
760:   This function is automatically called by `TSSetFromOptions()`

762: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSGetAdapt()`, `TSAdaptSetType()`, `TSAdaptSetAlwaysAccept()`, `TSAdaptSetSafety()`,
763:           `TSAdaptSetClip()`, `TSAdaptSetScaleSolveFailed()`, `TSAdaptSetStepLimits()`, `TSAdaptSetMonitor()`
764: @*/
765: PetscErrorCode TSAdaptSetFromOptions(TSAdapt adapt, PetscOptionItems PetscOptionsObject)
766: {
767:   char      type[256] = TSADAPTBASIC;
768:   PetscReal safety, reject_safety, clip[2], scale, hmin, hmax;
769:   PetscBool set, flg;
770:   PetscInt  two;

772:   PetscFunctionBegin;
774:   /* This should use PetscOptionsBegin() if/when this becomes an object used outside of TS, but currently this
775:    * function can only be called from inside TSSetFromOptions()  */
776:   PetscOptionsHeadBegin(PetscOptionsObject, "TS Adaptivity options");
777:   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));
778:   if (flg || !((PetscObject)adapt)->type_name) PetscCall(TSAdaptSetType(adapt, type));

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

783:   safety        = adapt->safety;
784:   reject_safety = adapt->reject_safety;
785:   PetscCall(PetscOptionsReal("-ts_adapt_safety", "Safety factor relative to target error/stability goal", "TSAdaptSetSafety", safety, &safety, &set));
786:   PetscCall(PetscOptionsReal("-ts_adapt_reject_safety", "Extra safety factor to apply if the last step was rejected", "TSAdaptSetSafety", reject_safety, &reject_safety, &flg));
787:   if (set || flg) PetscCall(TSAdaptSetSafety(adapt, safety, reject_safety));

789:   two     = 2;
790:   clip[0] = adapt->clip[0];
791:   clip[1] = adapt->clip[1];
792:   PetscCall(PetscOptionsRealArray("-ts_adapt_clip", "Admissible decrease/increase factor in step size", "TSAdaptSetClip", clip, &two, &set));
793:   PetscCheck(!set || (two == 2), PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_OUTOFRANGE, "Must give exactly two values to -ts_adapt_clip");
794:   if (set) PetscCall(TSAdaptSetClip(adapt, clip[0], clip[1]));

796:   hmin = adapt->dt_min;
797:   hmax = adapt->dt_max;
798:   PetscCall(PetscOptionsReal("-ts_adapt_dt_min", "Minimum time step considered", "TSAdaptSetStepLimits", hmin, &hmin, &set));
799:   PetscCall(PetscOptionsReal("-ts_adapt_dt_max", "Maximum time step considered", "TSAdaptSetStepLimits", hmax, &hmax, &flg));
800:   if (set || flg) PetscCall(TSAdaptSetStepLimits(adapt, hmin, hmax));

802:   PetscCall(PetscOptionsReal("-ts_adapt_max_ignore", "Adaptor ignores (absolute) solution values smaller than this value", "", adapt->ignore_max, &adapt->ignore_max, &set));
803:   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));

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

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

811:   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));

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

816:   PetscTryTypeMethod(adapt, setfromoptions, PetscOptionsObject);
817:   PetscOptionsHeadEnd();
818:   PetscFunctionReturn(PETSC_SUCCESS);
819: }

821: /*@
822:   TSAdaptCandidatesClear - clear any previously set candidate schemes

824:   Logically Collective

826:   Input Parameter:
827: . adapt - adaptive controller

829:   Level: developer

831: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptCreate()`, `TSAdaptCandidateAdd()`, `TSAdaptChoose()`
832: @*/
833: PetscErrorCode TSAdaptCandidatesClear(TSAdapt adapt)
834: {
835:   PetscFunctionBegin;
837:   PetscCall(PetscMemzero(&adapt->candidates, sizeof(adapt->candidates)));
838:   PetscFunctionReturn(PETSC_SUCCESS);
839: }

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

844:   Logically Collective; No Fortran Support

846:   Input Parameters:
847: + adapt      - time step adaptivity context, obtained with `TSGetAdapt()` or `TSAdaptCreate()`
848: . name       - name of the candidate scheme to add
849: . order      - order of the candidate scheme
850: . stageorder - stage order of the candidate scheme
851: . ccfl       - stability coefficient relative to explicit Euler, used for CFL constraints
852: . cost       - relative measure of the amount of work required for the candidate scheme
853: - inuse      - indicates that this scheme is the one currently in use, this flag can only be set for one scheme

855:   Level: developer

857: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptCandidatesClear()`, `TSAdaptChoose()`
858: @*/
859: PetscErrorCode TSAdaptCandidateAdd(TSAdapt adapt, const char name[], PetscInt order, PetscInt stageorder, PetscReal ccfl, PetscReal cost, PetscBool inuse)
860: {
861:   PetscInt c;

863:   PetscFunctionBegin;
865:   PetscCheck(order >= 1, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_OUTOFRANGE, "Classical order %" PetscInt_FMT " must be a positive integer", order);
866:   if (inuse) {
867:     PetscCheck(!adapt->candidates.inuse_set, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_WRONGSTATE, "Cannot set the inuse method twice, maybe forgot to call TSAdaptCandidatesClear()");
868:     adapt->candidates.inuse_set = PETSC_TRUE;
869:   }
870:   /* first slot if this is the current scheme, otherwise the next available slot */
871:   c = inuse ? 0 : !adapt->candidates.inuse_set + adapt->candidates.n;

873:   adapt->candidates.name[c]       = name;
874:   adapt->candidates.order[c]      = order;
875:   adapt->candidates.stageorder[c] = stageorder;
876:   adapt->candidates.ccfl[c]       = ccfl;
877:   adapt->candidates.cost[c]       = cost;
878:   adapt->candidates.n++;
879:   PetscFunctionReturn(PETSC_SUCCESS);
880: }

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

885:   Not Collective

887:   Input Parameter:
888: . adapt - time step adaptivity context

890:   Output Parameters:
891: + n          - number of candidate schemes, always at least 1
892: . order      - the order of each candidate scheme
893: . stageorder - the stage order of each candidate scheme
894: . ccfl       - the CFL coefficient of each scheme
895: - cost       - the relative cost of each scheme

897:   Level: developer

899:   Note:
900:   The current scheme is always returned in the first slot

902: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptCandidatesClear()`, `TSAdaptCandidateAdd()`, `TSAdaptChoose()`
903: @*/
904: PetscErrorCode TSAdaptCandidatesGet(TSAdapt adapt, PetscInt *n, const PetscInt **order, const PetscInt **stageorder, const PetscReal **ccfl, const PetscReal **cost)
905: {
906:   PetscFunctionBegin;
908:   if (n) *n = adapt->candidates.n;
909:   if (order) *order = adapt->candidates.order;
910:   if (stageorder) *stageorder = adapt->candidates.stageorder;
911:   if (ccfl) *ccfl = adapt->candidates.ccfl;
912:   if (cost) *cost = adapt->candidates.cost;
913:   PetscFunctionReturn(PETSC_SUCCESS);
914: }

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

919:   Collective

921:   Input Parameters:
922: + adapt - adaptive controller
923: . ts    - time stepper
924: - h     - current step size

926:   Output Parameters:
927: + next_sc - optional, scheme to use for the next step
928: . next_h  - step size to use for the next step
929: - accept  - `PETSC_TRUE` to accept the current step, `PETSC_FALSE` to repeat the current step with the new step size

931:   Level: developer

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

937: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSAdaptCandidatesClear()`, `TSAdaptCandidateAdd()`
938: @*/
939: PetscErrorCode TSAdaptChoose(TSAdapt adapt, TS ts, PetscReal h, PetscInt *next_sc, PetscReal *next_h, PetscBool *accept)
940: {
941:   PetscInt  ncandidates = adapt->candidates.n;
942:   PetscInt  scheme      = 0;
943:   PetscReal wlte        = -1.0;
944:   PetscReal wltea       = -1.0;
945:   PetscReal wlter       = -1.0;

947:   PetscFunctionBegin;
950:   if (next_sc) PetscAssertPointer(next_sc, 4);
951:   PetscAssertPointer(next_h, 5);
952:   PetscAssertPointer(accept, 6);
953:   if (next_sc) *next_sc = 0;

955:   /* Do not mess with adaptivity while handling events */
956:   if (ts->event && ts->event->processing) {
957:     *next_h = h;
958:     *accept = PETSC_TRUE;
959:     if (adapt->monitor) {
960:       PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));

962:       if (ts->event->iterctr == 0) {
963:         /*
964:           An event has been found, now finalising the event processing: performing the 1st and 2nd post-event steps.
965:           Entering this if-branch means both these steps (set to either PETSC_DECIDE or numerical value) are managed
966:           by the event handler. In this case the 1st post-event step is always accepted, without interference of TSAdapt.
967:           Note: if the 2nd post-event step is not managed by the event handler (e.g. given 1st = numerical, 2nd = PETSC_DECIDE),
968:           this if-branch is not entered, and TSAdapt may reject/adjust the proposed 1st post-event step.
969:         */
970:         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));
971:       } else PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "TSAdapt does not interfere, step %3" PetscInt_FMT " accepted. Event handling in progress\n", ts->steps));

973:       PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
974:     }
975:     PetscFunctionReturn(PETSC_SUCCESS);
976:   }

978:   PetscUseTypeMethod(adapt, choose, ts, h, &scheme, next_h, accept, &wlte, &wltea, &wlter);
979:   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);
980:   PetscCheck(*next_h >= 0, PetscObjectComm((PetscObject)adapt), PETSC_ERR_ARG_OUTOFRANGE, "Computed step size %g must be positive", (double)*next_h);
981:   if (next_sc) *next_sc = scheme;

983:   if (*accept && ts->exact_final_time == TS_EXACTFINALTIME_MATCHSTEP) {
984:     /* Increase/reduce step size if end time of next step is close to or overshoots max time */
985:     PetscReal t = ts->ptime + ts->time_step, tend, tmax, h1, hmax;
986:     PetscReal a = (PetscReal)(1.0 + adapt->matchstepfac[0]);
987:     PetscReal b = adapt->matchstepfac[1];

989:     /*
990:       Logic in using 'dt_span_cached':
991:       1. It always overrides *next_h, except (any of):
992:          a) the current step was rejected,
993:          b) the adaptor proposed to decrease the next step,
994:          c) the adaptor proposed *next_h > dt_span_cached.
995:       2. If *next_h was adjusted by eval_times points (or the final point):
996:            -- when dt_span_cached is filled (>0), it keeps its value,
997:            -- when dt_span_cached is clear (==0), it gets the unadjusted version of *next_h.
998:       3. If *next_h was not adjusted as in (2), dt_span_cached is cleared.
999:       Note, if a combination (1.b || 1.c) && (3) takes place, this means that
1000:       dt_span_cached remains unused at the moment of clearing.
1001:       If (1.a) takes place, dt_span_cached keeps its value.
1002:       Also, dt_span_cached can be updated by the event handler, see tsevent.c.
1003:     */
1004:     if (h <= *next_h && *next_h <= adapt->dt_eval_times_cached) *next_h = adapt->dt_eval_times_cached; /* try employing the cache */
1005:     h1   = *next_h;
1006:     tend = t + h1;

1008:     if (ts->eval_times && ts->eval_times->time_point_idx < ts->eval_times->num_time_points) {
1009:       PetscCheck(ts->eval_times->worktol == 0, PetscObjectComm((PetscObject)adapt), PETSC_ERR_PLIB, "Unexpected state (tspan->worktol != 0) in TSAdaptChoose()");
1010:       ts->eval_times->worktol = ts->eval_times->reltol * h1 + ts->eval_times->abstol;
1011:       if (PetscIsCloseAtTol(t, ts->eval_times->time_points[ts->eval_times->time_point_idx], ts->eval_times->worktol, 0)) /* hit a span time point */
1012:         if (ts->eval_times->time_point_idx + 1 < ts->eval_times->num_time_points) tmax = ts->eval_times->time_points[ts->eval_times->time_point_idx + 1];
1013:         else tmax = ts->max_time; /* hit the last span time point */
1014:       else tmax = ts->eval_times->time_points[ts->eval_times->time_point_idx];
1015:     } else tmax = ts->max_time;
1016:     tmax = PetscMin(tmax, ts->max_time);
1017:     hmax = tmax - t;

1019:     if (t < tmax && tend > tmax) *next_h = hmax;
1020:     if (t < tmax && tend < tmax && h1 * b > hmax) *next_h = hmax / 2;
1021:     if (t < tmax && tend < tmax && h1 * a > hmax) *next_h = hmax;
1022:     if (ts->eval_times && h1 != *next_h && !adapt->dt_eval_times_cached) adapt->dt_eval_times_cached = h1; /* cache the step size if it is to be changed    */
1023:     if (ts->eval_times && h1 == *next_h && adapt->dt_eval_times_cached) adapt->dt_eval_times_cached = 0;   /* clear the cache if the step size is unchanged */
1024:   }
1025:   if (adapt->monitor) {
1026:     const char *sc_name = (scheme < ncandidates) ? adapt->candidates.name[scheme] : "";
1027:     PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1028:     if (wlte < 0) {
1029:       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",
1030:                                        (double)ts->ptime, (double)h, (double)*next_h));
1031:     } else {
1032:       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",
1033:                                        (double)ts->ptime, (double)h, (double)*next_h, (double)wlte, (double)wltea, (double)wlter));
1034:     }
1035:     PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1036:   }
1037:   PetscFunctionReturn(PETSC_SUCCESS);
1038: }

1040: /*@
1041:   TSAdaptSetTimeStepIncreaseDelay - The number of timesteps to wait after a decrease in the timestep due to failed solver
1042:   before increasing the time step.

1044:   Logicially Collective

1046:   Input Parameters:
1047: + adapt - adaptive controller context
1048: - cnt   - the number of timesteps

1050:   Options Database Key:
1051: . -ts_adapt_time_step_increase_delay cnt - number of steps to delay the increase

1053:   Level: advanced

1055:   Notes:
1056:   This is to prevent an adaptor from bouncing back and forth between two nearby timesteps. The default is 0.

1058:   The successful use of this option is problem dependent

1060:   Developer Notes:
1061:   There is no theory to support this option

1063: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`
1064: @*/
1065: PetscErrorCode TSAdaptSetTimeStepIncreaseDelay(TSAdapt adapt, PetscInt cnt)
1066: {
1067:   PetscFunctionBegin;
1068:   adapt->timestepjustdecreased_delay = cnt;
1069:   PetscFunctionReturn(PETSC_SUCCESS);
1070: }

1072: /*@
1073:   TSAdaptCheckStage - checks whether to accept a stage, (e.g. reject and change time step size if nonlinear solve fails or solution vector is infeasible)

1075:   Collective

1077:   Input Parameters:
1078: + adapt - adaptive controller context
1079: . ts    - time stepper
1080: . t     - Current simulation time
1081: - Y     - Current solution vector

1083:   Output Parameter:
1084: . accept - `PETSC_TRUE` to accept the stage, `PETSC_FALSE` to reject

1086:   Level: developer

1088: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`
1089: @*/
1090: PetscErrorCode TSAdaptCheckStage(TSAdapt adapt, TS ts, PetscReal t, Vec Y, PetscBool *accept)
1091: {
1092:   SNESConvergedReason snesreason = SNES_CONVERGED_ITERATING;
1093:   PetscBool           func_accept;
1094:   char                reject_stage_message[128];

1096:   PetscFunctionBegin;
1099:   PetscAssertPointer(accept, 5);
1100:   *accept = PETSC_TRUE;

1102:   if (adapt->checkstage) {
1103:     PetscCallBack("TSAdapt callback check stage", (*adapt->checkstage)(adapt, ts, t, Y, accept));
1104:     if (!*accept) {
1105:       PetscCall(PetscStrncpy(reject_stage_message, "rejected by TSAdaptSetCheckStage", sizeof reject_stage_message));
1106:       goto reject_stage;
1107:     }
1108:   }

1110:   PetscCall(TSFunctionDomainError(ts, t, Y, &func_accept));
1111:   if (!func_accept) {
1112:     PetscCall(PetscStrncpy(reject_stage_message, "rejected by TSSetFunctionDomainError()", sizeof reject_stage_message));
1113:     goto reject_stage;
1114:   }

1116:   if (ts->snes) PetscCall(SNESGetConvergedReason(ts->snes, &snesreason));
1117:   if (snesreason < 0) {
1118:     // SNES_DIVERGED_FUNCTION_DOMAIN should not count against ts->max_snes_failures, see !6581 and commit 6c6709e3a
1119:     if (snesreason != SNES_DIVERGED_FUNCTION_DOMAIN && ++ts->num_snes_failures >= ts->max_snes_failures && ts->max_snes_failures != PETSC_UNLIMITED) {
1120:       ts->reason = TS_DIVERGED_NONLINEAR_SOLVE;
1121:       PetscCall(PetscSNPrintf(reject_stage_message, sizeof reject_stage_message, "nonlinear solve failures %" PetscInt_FMT " greater than current TS allowed, stopping solve", ts->num_snes_failures));
1122:     } else PetscCall(PetscSNPrintf(reject_stage_message, sizeof reject_stage_message, "SNES solve failure %s", SNESConvergedReasons[snesreason]));
1123:     goto reject_stage;
1124:   }
1125:   PetscFunctionReturn(PETSC_SUCCESS);

1127: reject_stage:
1128:   *accept = PETSC_FALSE;
1129:   PetscCall(PetscInfo(ts, "Step=%" PetscInt_FMT ", %s\n", ts->steps, reject_stage_message));
1130:   if (adapt->monitor) {
1131:     PetscCall(PetscViewerASCIIAddTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1132:     PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "TSAdapt %s step %3" PetscInt_FMT " stage rejected t=%-11g+%10.3e, %s", ((PetscObject)adapt)->type_name, ts->steps, (double)ts->ptime, (double)ts->time_step, reject_stage_message));
1133:     PetscCall(PetscViewerASCIISubtractTab(adapt->monitor, ((PetscObject)adapt)->tablevel));
1134:   }
1135:   if (!ts->reason) {
1136:     PetscReal dt, new_dt;
1137:     PetscCall(TSGetTimeStep(ts, &dt));
1138:     new_dt = dt * adapt->scale_solve_failed;
1139:     PetscCall(TSSetTimeStep(ts, new_dt));
1140:     adapt->timestepjustdecreased += adapt->timestepjustdecreased_delay;
1141:     if (adapt->monitor) PetscCall(PetscViewerASCIIPrintf(adapt->monitor, ", retrying with dt=%-10.3e\n", (double)new_dt));
1142:   } else if (adapt->monitor) {
1143:     PetscCall(PetscViewerASCIIPrintf(adapt->monitor, "\n"));
1144:   }
1145:   PetscFunctionReturn(PETSC_SUCCESS);
1146: }

1148: /*@
1149:   TSAdaptCreate - create an adaptive controller context for time stepping

1151:   Collective

1153:   Input Parameter:
1154: . comm - The communicator

1156:   Output Parameter:
1157: . inadapt - new `TSAdapt` object

1159:   Level: developer

1161:   Note:
1162:   `TSAdapt` creation is handled by `TS`, so users should not need to call this function.

1164: .seealso: [](ch_ts), [](sec_ts_error_control), `TSAdapt`, `TSGetAdapt()`, `TSAdaptSetType()`, `TSAdaptDestroy()`
1165: @*/
1166: PetscErrorCode TSAdaptCreate(MPI_Comm comm, TSAdapt *inadapt)
1167: {
1168:   TSAdapt adapt;

1170:   PetscFunctionBegin;
1171:   PetscAssertPointer(inadapt, 2);
1172:   PetscCall(TSAdaptInitializePackage());

1174:   PetscCall(PetscHeaderCreate(adapt, TSADAPT_CLASSID, "TSAdapt", "Time stepping adaptivity", "TS", comm, TSAdaptDestroy, TSAdaptView));
1175:   adapt->always_accept      = PETSC_FALSE;
1176:   adapt->safety             = 0.9;
1177:   adapt->reject_safety      = 0.5;
1178:   adapt->clip[0]            = 0.1;
1179:   adapt->clip[1]            = 10.;
1180:   adapt->dt_min             = 1e-20;
1181:   adapt->dt_max             = 1e+20;
1182:   adapt->ignore_max         = -1.0;
1183:   adapt->glee_use_local     = PETSC_TRUE;
1184:   adapt->scale_solve_failed = 0.25;
1185:   /* these two safety factors are not public, and they are used only in the TS_EXACTFINALTIME_MATCHSTEP case
1186:      to prevent from situations were unreasonably small time steps are taken in order to match the final time */
1187:   adapt->matchstepfac[0]             = 0.01; /* allow 1% step size increase in the last step */
1188:   adapt->matchstepfac[1]             = 2.0;  /* halve last step if it is greater than what remains divided this factor */
1189:   adapt->wnormtype                   = NORM_2;
1190:   adapt->timestepjustdecreased_delay = 0;
1191:   *inadapt                           = adapt;
1192:   PetscFunctionReturn(PETSC_SUCCESS);
1193: }