Actual source code: linesearch.c
1: #include <petsc/private/linesearchimpl.h>
3: PetscBool SNESLineSearchRegisterAllCalled = PETSC_FALSE;
4: PetscFunctionList SNESLineSearchList = NULL;
6: PetscClassId SNESLINESEARCH_CLASSID;
7: PetscLogEvent SNESLINESEARCH_Apply;
9: /*@
10: SNESLineSearchMonitorCancel - Clears all the monitor functions for a `SNESLineSearch` object.
12: Logically Collective
14: Input Parameter:
15: . ls - the `SNESLineSearch` context
17: Options Database Key:
18: . -snes_linesearch_monitor_cancel - cancels all monitors that have been hardwired
19: into a code by calls to `SNESLineSearchMonitorSet()`, but does not cancel those
20: set via the options database
22: Level: advanced
24: Notes:
25: There is no way to clear one specific monitor from a `SNESLineSearch` object.
27: This does not clear the monitor set with `SNESLineSearchSetDefaultMonitor()` use `SNESLineSearchSetDefaultMonitor`(`ls`,`NULL`) to cancel it
28: that one.
30: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchMonitorDefault()`, `SNESLineSearchMonitorSet()`
31: @*/
32: PetscErrorCode SNESLineSearchMonitorCancel(SNESLineSearch ls)
33: {
34: PetscInt i;
36: PetscFunctionBegin;
38: for (i = 0; i < ls->numbermonitors; i++) {
39: if (ls->monitordestroy[i]) PetscCall((*ls->monitordestroy[i])(&ls->monitorcontext[i]));
40: }
41: ls->numbermonitors = 0;
42: PetscFunctionReturn(PETSC_SUCCESS);
43: }
45: /*@
46: SNESLineSearchMonitor - runs the user provided monitor routines, if they exist
48: Collective
50: Input Parameter:
51: . ls - the linesearch object
53: Level: developer
55: Note:
56: This routine is called by the `SNESLineSearch` implementations.
57: It does not typically need to be called by the user.
59: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchMonitorSet()`
60: @*/
61: PetscErrorCode SNESLineSearchMonitor(SNESLineSearch ls)
62: {
63: PetscInt i, n = ls->numbermonitors;
65: PetscFunctionBegin;
66: for (i = 0; i < n; i++) PetscCall((*ls->monitorftns[i])(ls, ls->monitorcontext[i]));
67: PetscFunctionReturn(PETSC_SUCCESS);
68: }
70: /*@C
71: SNESLineSearchMonitorSet - Sets an ADDITIONAL function that is to be used at every
72: iteration of the nonlinear solver to display the iteration's
73: progress.
75: Logically Collective
77: Input Parameters:
78: + ls - the `SNESLineSearch` context
79: . f - the monitor function
80: . mctx - [optional] user-defined context for private data for the monitor routine (use `NULL` if no context is desired)
81: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
83: Calling sequence of `f`:
84: + ls - the `SNESLineSearch` context
85: - mctx - [optional] user-defined context for private data for the monitor routine
87: Level: intermediate
89: Note:
90: Several different monitoring routines may be set by calling
91: `SNESLineSearchMonitorSet()` multiple times; all will be called in the
92: order in which they were set.
94: Fortran Note:
95: Only a single monitor function can be set for each `SNESLineSearch` object
97: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchMonitorDefault()`, `SNESLineSearchMonitorCancel()`, `PetscCtxDestroyFn`
98: @*/
99: PetscErrorCode SNESLineSearchMonitorSet(SNESLineSearch ls, PetscErrorCode (*f)(SNESLineSearch ls, void *mctx), void *mctx, PetscCtxDestroyFn *monitordestroy)
100: {
101: PetscInt i;
102: PetscBool identical;
104: PetscFunctionBegin;
106: for (i = 0; i < ls->numbermonitors; i++) {
107: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))f, mctx, monitordestroy, (PetscErrorCode (*)(void))ls->monitorftns[i], ls->monitorcontext[i], ls->monitordestroy[i], &identical));
108: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
109: }
110: PetscCheck(ls->numbermonitors < MAXSNESLSMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
111: ls->monitorftns[ls->numbermonitors] = f;
112: ls->monitordestroy[ls->numbermonitors] = monitordestroy;
113: ls->monitorcontext[ls->numbermonitors++] = mctx;
114: PetscFunctionReturn(PETSC_SUCCESS);
115: }
117: /*@C
118: SNESLineSearchMonitorSolutionUpdate - Monitors each update of the function value the linesearch tries
120: Collective
122: Input Parameters:
123: + ls - the `SNESLineSearch` object
124: - vf - the context for the monitor, in this case it is an `PetscViewerAndFormat`
126: Options Database Key:
127: . -snes_linesearch_monitor_solution_update [viewer:filename:format] - view each update tried by line search routine
129: Level: developer
131: This is not normally called directly but is passed to `SNESLineSearchMonitorSet()`
133: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchMonitorSet()`, `SNESMonitorSolution()`
134: @*/
135: PetscErrorCode SNESLineSearchMonitorSolutionUpdate(SNESLineSearch ls, PetscViewerAndFormat *vf)
136: {
137: PetscViewer viewer = vf->viewer;
138: Vec Y, W, G;
140: PetscFunctionBegin;
141: PetscCall(SNESLineSearchGetVecs(ls, NULL, NULL, &Y, &W, &G));
142: PetscCall(PetscViewerPushFormat(viewer, vf->format));
143: PetscCall(PetscViewerASCIIPrintf(viewer, "LineSearch attempted update to solution \n"));
144: PetscCall(VecView(Y, viewer));
145: PetscCall(PetscViewerASCIIPrintf(viewer, "LineSearch attempted new solution \n"));
146: PetscCall(VecView(W, viewer));
147: PetscCall(PetscViewerASCIIPrintf(viewer, "LineSearch attempted updated function value\n"));
148: PetscCall(VecView(G, viewer));
149: PetscCall(PetscViewerPopFormat(viewer));
150: PetscFunctionReturn(PETSC_SUCCESS);
151: }
153: /*@
154: SNESLineSearchCreate - Creates a `SNESLineSearch` context.
156: Logically Collective
158: Input Parameter:
159: . comm - MPI communicator for the line search (typically from the associated `SNES` context).
161: Output Parameter:
162: . outlinesearch - the new line search context
164: Level: developer
166: Note:
167: The preferred calling sequence is to use `SNESGetLineSearch()` to acquire the `SNESLineSearch` instance
168: already associated with the `SNES`.
170: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `LineSearchDestroy()`, `SNESGetLineSearch()`
171: @*/
172: PetscErrorCode SNESLineSearchCreate(MPI_Comm comm, SNESLineSearch *outlinesearch)
173: {
174: SNESLineSearch linesearch;
176: PetscFunctionBegin;
177: PetscAssertPointer(outlinesearch, 2);
178: PetscCall(SNESInitializePackage());
180: PetscCall(PetscHeaderCreate(linesearch, SNESLINESEARCH_CLASSID, "SNESLineSearch", "Linesearch", "SNESLineSearch", comm, SNESLineSearchDestroy, SNESLineSearchView));
181: linesearch->vec_sol_new = NULL;
182: linesearch->vec_func_new = NULL;
183: linesearch->vec_sol = NULL;
184: linesearch->vec_func = NULL;
185: linesearch->vec_update = NULL;
187: linesearch->lambda = 1.0;
188: linesearch->fnorm = 1.0;
189: linesearch->ynorm = 1.0;
190: linesearch->xnorm = 1.0;
191: linesearch->result = SNES_LINESEARCH_SUCCEEDED;
192: linesearch->norms = PETSC_TRUE;
193: linesearch->keeplambda = PETSC_FALSE;
194: linesearch->damping = 1.0;
195: linesearch->maxlambda = 1.0;
196: linesearch->minlambda = 1e-12;
197: linesearch->rtol = 1e-8;
198: linesearch->atol = 1e-15;
199: linesearch->ltol = 1e-8;
200: linesearch->precheckctx = NULL;
201: linesearch->postcheckctx = NULL;
202: linesearch->max_it = 1;
203: linesearch->setupcalled = PETSC_FALSE;
204: linesearch->monitor = NULL;
205: *outlinesearch = linesearch;
206: PetscFunctionReturn(PETSC_SUCCESS);
207: }
209: /*@
210: SNESLineSearchSetUp - Prepares the line search for being applied by allocating
211: any required vectors.
213: Collective
215: Input Parameter:
216: . linesearch - The `SNESLineSearch` instance.
218: Level: advanced
220: Note:
221: For most cases, this needn't be called by users or outside of `SNESLineSearchApply()`.
222: The only current case where this is called outside of this is for the VI
223: solvers, which modify the solution and work vectors before the first call
224: of `SNESLineSearchApply()`, requiring the `SNESLineSearch` work vectors to be
225: allocated upfront.
227: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchReset()`
228: @*/
229: PetscErrorCode SNESLineSearchSetUp(SNESLineSearch linesearch)
230: {
231: PetscFunctionBegin;
232: if (!((PetscObject)linesearch)->type_name) PetscCall(SNESLineSearchSetType(linesearch, SNESLINESEARCHBASIC));
233: if (!linesearch->setupcalled) {
234: if (!linesearch->vec_sol_new) PetscCall(VecDuplicate(linesearch->vec_sol, &linesearch->vec_sol_new));
235: if (!linesearch->vec_func_new) PetscCall(VecDuplicate(linesearch->vec_sol, &linesearch->vec_func_new));
236: PetscTryTypeMethod(linesearch, setup);
237: if (!linesearch->ops->snesfunc) PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunction));
238: linesearch->lambda = linesearch->damping;
239: linesearch->setupcalled = PETSC_TRUE;
240: }
241: PetscFunctionReturn(PETSC_SUCCESS);
242: }
244: /*@
245: SNESLineSearchReset - Undoes the `SNESLineSearchSetUp()` and deletes any `Vec`s or `Mat`s allocated by the line search.
247: Collective
249: Input Parameter:
250: . linesearch - The `SNESLineSearch` instance.
252: Level: developer
254: Note:
255: Usually only called by `SNESReset()`
257: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchSetUp()`
258: @*/
259: PetscErrorCode SNESLineSearchReset(SNESLineSearch linesearch)
260: {
261: PetscFunctionBegin;
262: PetscTryTypeMethod(linesearch, reset);
264: PetscCall(VecDestroy(&linesearch->vec_sol_new));
265: PetscCall(VecDestroy(&linesearch->vec_func_new));
267: PetscCall(VecDestroyVecs(linesearch->nwork, &linesearch->work));
269: linesearch->nwork = 0;
270: linesearch->setupcalled = PETSC_FALSE;
271: PetscFunctionReturn(PETSC_SUCCESS);
272: }
274: /*@C
275: SNESLineSearchSetFunction - Sets the function evaluation used by the `SNES` line search
276: `
278: Input Parameters:
279: + linesearch - the `SNESLineSearch` context
280: - func - function evaluation routine, this is usually the function provided with `SNESSetFunction()`
282: Calling sequence of `func`:
283: + snes - the `SNES` with which the `SNESLineSearch` context is associated with
284: . x - the input vector
285: - f - the computed value of the function
287: Level: developer
289: Note:
290: By default the `SNESLineSearch` uses the function provided by `SNESSetFunction()` so this is rarely needed
292: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESSetFunction()`
293: @*/
294: PetscErrorCode SNESLineSearchSetFunction(SNESLineSearch linesearch, PetscErrorCode (*func)(SNES snes, Vec x, Vec f))
295: {
296: PetscFunctionBegin;
298: linesearch->ops->snesfunc = func;
299: PetscFunctionReturn(PETSC_SUCCESS);
300: }
302: /*@C
303: SNESLineSearchSetPreCheck - Sets a function that is called after the initial search direction has been computed but
304: before the line search routine has been applied. Allows adjusting the result of (usually a linear solve) that
305: determined the search direction.
307: Logically Collective
309: Input Parameters:
310: + linesearch - the `SNESLineSearch` context
311: . func - [optional] function evaluation routine
312: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
314: Calling sequence of `func`:
315: + ls - the `SNESLineSearch` context
316: . x - the current solution
317: . d - the current search direction
318: . changed_d - indicates if the search direction has been changed
319: - ctx - the context passed to `SNESLineSearchSetPreCheck()`
321: Level: intermediate
323: Note:
324: Use `SNESLineSearchSetPostCheck()` to change the step after the line search is complete.
326: Use `SNESVISetVariableBounds()` and `SNESVISetComputeVariableBounds()` to cause `SNES` to automatically control the ranges of variables allowed.
328: .seealso: [](ch_snes), `SNES`, `SNESGetLineSearch()`, `SNESLineSearchPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchGetPreCheck()`,
329: `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()`, `SNESSetFunctionDomainError()`, `SNESSetJacobianDomainError()`
331: @*/
332: PetscErrorCode SNESLineSearchSetPreCheck(SNESLineSearch linesearch, PetscErrorCode (*func)(SNESLineSearch ls, Vec x, Vec d, PetscBool *changed_d, void *ctx), void *ctx)
333: {
334: PetscFunctionBegin;
336: if (func) linesearch->ops->precheck = func;
337: if (ctx) linesearch->precheckctx = ctx;
338: PetscFunctionReturn(PETSC_SUCCESS);
339: }
341: /*@C
342: SNESLineSearchGetPreCheck - Gets the pre-check function for the line search routine.
344: Input Parameter:
345: . linesearch - the `SNESLineSearch` context
347: Output Parameters:
348: + func - [optional] function evaluation routine, for calling sequence see `SNESLineSearchSetPreCheck()`
349: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
351: Level: intermediate
353: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchPreCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
354: @*/
355: PetscErrorCode SNESLineSearchGetPreCheck(SNESLineSearch linesearch, PetscErrorCode (**func)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void **ctx)
356: {
357: PetscFunctionBegin;
359: if (func) *func = linesearch->ops->precheck;
360: if (ctx) *ctx = linesearch->precheckctx;
361: PetscFunctionReturn(PETSC_SUCCESS);
362: }
364: /*@C
365: SNESLineSearchSetPostCheck - Sets a user function that is called after the line search has been applied to determine the step
366: direction and length. Allows the user a chance to change or override the decision of the line search routine
368: Logically Collective
370: Input Parameters:
371: + linesearch - the `SNESLineSearch` context
372: . func - [optional] function evaluation routine
373: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
375: Calling sequence of `func`:
376: + ls - the `SNESLineSearch` context
377: . x - the current solution
378: . d - the current search direction
379: . w - $ w = x + lambda*d $ for some lambda
380: . changed_d - indicates if the search direction `d` has been changed
381: . changed_w - indicates `w` has been changed
382: - ctx - the context passed to `SNESLineSearchSetPreCheck()`
384: Level: intermediate
386: Notes:
387: Use `SNESLineSearchSetPreCheck()` to change the step before the line search is completed.
388: The calling sequence of the callback does not contain the current scaling factor. To access the value, use `SNESLineSearchGetLambda()`.
390: Use `SNESVISetVariableBounds()` and `SNESVISetComputeVariableBounds()` to cause `SNES` to automatically control the ranges of variables allowed.
392: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`, `SNESLineSearchGetPostCheck()`,
393: `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()`, `SNESSetFunctionDomainError()`, `SNESSetJacobianDomainError()`
394: @*/
395: PetscErrorCode SNESLineSearchSetPostCheck(SNESLineSearch linesearch, PetscErrorCode (*func)(SNESLineSearch ls, Vec x, Vec d, Vec w, PetscBool *changed_d, PetscBool *changed_w, void *ctx), void *ctx)
396: {
397: PetscFunctionBegin;
399: if (func) linesearch->ops->postcheck = func;
400: if (ctx) linesearch->postcheckctx = ctx;
401: PetscFunctionReturn(PETSC_SUCCESS);
402: }
404: /*@C
405: SNESLineSearchGetPostCheck - Gets the post-check function for the line search routine.
407: Input Parameter:
408: . linesearch - the `SNESLineSearch` context
410: Output Parameters:
411: + func - [optional] function evaluation routine, see for the calling sequence `SNESLineSearchSetPostCheck()`
412: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
414: Level: intermediate
416: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchGetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchPostCheck()`, `SNESLineSearchSetPreCheck()`
417: @*/
418: PetscErrorCode SNESLineSearchGetPostCheck(SNESLineSearch linesearch, PetscErrorCode (**func)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx)
419: {
420: PetscFunctionBegin;
422: if (func) *func = linesearch->ops->postcheck;
423: if (ctx) *ctx = linesearch->postcheckctx;
424: PetscFunctionReturn(PETSC_SUCCESS);
425: }
427: /*@
428: SNESLineSearchPreCheck - Prepares the line search for being applied.
430: Logically Collective
432: Input Parameters:
433: + linesearch - The linesearch instance.
434: . X - The current solution
435: - Y - The step direction
437: Output Parameter:
438: . changed - Indicator that the precheck routine has changed `Y`
440: Level: advanced
442: Note:
443: This calls any function provided with `SNESLineSearchSetPreCheck()` and is called automatically inside the line search routines
445: Developer Note:
446: The use of `PetscObjectGetState()` would eliminate the need for the `changed` argument to be provided
448: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`, `SNESLineSearchSetPostCheck()`,
449: `SNESLineSearchGetPostCheck()`
450: @*/
451: PetscErrorCode SNESLineSearchPreCheck(SNESLineSearch linesearch, Vec X, Vec Y, PetscBool *changed)
452: {
453: PetscFunctionBegin;
454: *changed = PETSC_FALSE;
455: if (linesearch->ops->precheck) {
456: PetscUseTypeMethod(linesearch, precheck, X, Y, changed, linesearch->precheckctx);
458: }
459: PetscFunctionReturn(PETSC_SUCCESS);
460: }
462: /*@
463: SNESLineSearchPostCheck - Hook to modify step direction or updated solution after a successful linesearch
465: Logically Collective
467: Input Parameters:
468: + linesearch - The line search context
469: . X - The last solution
470: . Y - The step direction
471: - W - The updated solution, `W = X - lambda * Y` for some lambda
473: Output Parameters:
474: + changed_Y - Indicator if the direction `Y` has been changed.
475: - changed_W - Indicator if the new candidate solution `W` has been changed.
477: Level: developer
479: Note:
480: This calls any function provided with `SNESLineSearchSetPostCheck()` and is called automatically inside the line search routines
482: Developer Note:
483: The use of `PetscObjectGetState()` would eliminate the need for the `changed_Y` and `changed_W` arguments to be provided
485: .seealso: [](ch_snes), `SNES`, `SNESGetLineSearch()`, `SNESLineSearchPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPrecheck()`, `SNESLineSearchGetPrecheck()`
486: @*/
487: PetscErrorCode SNESLineSearchPostCheck(SNESLineSearch linesearch, Vec X, Vec Y, Vec W, PetscBool *changed_Y, PetscBool *changed_W)
488: {
489: PetscFunctionBegin;
490: *changed_Y = PETSC_FALSE;
491: *changed_W = PETSC_FALSE;
492: if (linesearch->ops->postcheck) {
493: PetscUseTypeMethod(linesearch, postcheck, X, Y, W, changed_Y, changed_W, linesearch->postcheckctx);
496: }
497: PetscFunctionReturn(PETSC_SUCCESS);
498: }
500: /*@C
501: SNESLineSearchPreCheckPicard - Implements a correction that is sometimes useful to improve the convergence rate of Picard iteration {cite}`hindmarsh1996time`
503: Logically Collective
505: Input Parameters:
506: + linesearch - the line search context
507: . X - base state for this step
508: - ctx - context for this function
510: Input/Output Parameter:
511: . Y - correction, possibly modified
513: Output Parameter:
514: . changed - flag indicating that `Y` was modified
516: Options Database Keys:
517: + -snes_linesearch_precheck_picard - activate this routine
518: - -snes_linesearch_precheck_picard_angle - angle
520: Level: advanced
522: Notes:
523: This function should be passed to `SNESLineSearchSetPreCheck()`
525: The justification for this method involves the linear convergence of a Picard iteration
526: so the Picard linearization should be provided in place of the "Jacobian" {cite}`hindmarsh1996time`. This correction
527: is generally not useful when using a Newton linearization.
529: Developer Note:
530: The use of `PetscObjectGetState()` would eliminate the need for the `changed` argument to be provided
532: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESSetPicard()`, `SNESGetLineSearch()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
533: @*/
534: PetscErrorCode SNESLineSearchPreCheckPicard(SNESLineSearch linesearch, Vec X, Vec Y, PetscBool *changed, void *ctx)
535: {
536: PetscReal angle = *(PetscReal *)linesearch->precheckctx;
537: Vec Ylast;
538: PetscScalar dot;
539: PetscInt iter;
540: PetscReal ynorm, ylastnorm, theta, angle_radians;
541: SNES snes;
543: PetscFunctionBegin;
544: PetscCall(SNESLineSearchGetSNES(linesearch, &snes));
545: PetscCall(PetscObjectQuery((PetscObject)snes, "SNESLineSearchPreCheckPicard_Ylast", (PetscObject *)&Ylast));
546: if (!Ylast) {
547: PetscCall(VecDuplicate(Y, &Ylast));
548: PetscCall(PetscObjectCompose((PetscObject)snes, "SNESLineSearchPreCheckPicard_Ylast", (PetscObject)Ylast));
549: PetscCall(PetscObjectDereference((PetscObject)Ylast));
550: }
551: PetscCall(SNESGetIterationNumber(snes, &iter));
552: if (iter < 2) {
553: PetscCall(VecCopy(Y, Ylast));
554: *changed = PETSC_FALSE;
555: PetscFunctionReturn(PETSC_SUCCESS);
556: }
558: PetscCall(VecDot(Y, Ylast, &dot));
559: PetscCall(VecNorm(Y, NORM_2, &ynorm));
560: PetscCall(VecNorm(Ylast, NORM_2, &ylastnorm));
561: if (ynorm == 0. || ylastnorm == 0.) {
562: *changed = PETSC_FALSE;
563: PetscFunctionReturn(PETSC_SUCCESS);
564: }
565: /* Compute the angle between the vectors Y and Ylast, clip to keep inside the domain of acos() */
566: theta = PetscAcosReal((PetscReal)PetscClipInterval(PetscAbsScalar(dot) / (ynorm * ylastnorm), -1.0, 1.0));
567: angle_radians = angle * PETSC_PI / 180.;
568: if (PetscAbsReal(theta) < angle_radians || PetscAbsReal(theta - PETSC_PI) < angle_radians) {
569: /* Modify the step Y */
570: PetscReal alpha, ydiffnorm;
571: PetscCall(VecAXPY(Ylast, -1.0, Y));
572: PetscCall(VecNorm(Ylast, NORM_2, &ydiffnorm));
573: alpha = (ydiffnorm > .001 * ylastnorm) ? ylastnorm / ydiffnorm : 1000.0;
574: PetscCall(VecCopy(Y, Ylast));
575: PetscCall(VecScale(Y, alpha));
576: PetscCall(PetscInfo(snes, "Angle %14.12e degrees less than threshold %14.12e, corrected step by alpha=%14.12e\n", (double)(theta * 180 / PETSC_PI), (double)angle, (double)alpha));
577: *changed = PETSC_TRUE;
578: } else {
579: PetscCall(PetscInfo(snes, "Angle %14.12e degrees exceeds threshold %14.12e, no correction applied\n", (double)(theta * 180 / PETSC_PI), (double)angle));
580: PetscCall(VecCopy(Y, Ylast));
581: *changed = PETSC_FALSE;
582: }
583: PetscFunctionReturn(PETSC_SUCCESS);
584: }
586: /*@
587: SNESLineSearchApply - Computes the line-search update.
589: Collective
591: Input Parameter:
592: . linesearch - The line search context
594: Input/Output Parameters:
595: + X - The current solution, on output the new solution
596: . F - The current function value, on output the new function value at the solution value `X`
597: . fnorm - The current norm of `F`, on output the new norm of `F`
598: - Y - The current search direction, on output the direction determined by the linesearch, i.e. `Xnew = Xold - lambda*Y`
600: Options Database Keys:
601: + -snes_linesearch_type - basic (or equivalently none), bt, secant, cp, nleqerr, bisection, shell
602: . -snes_linesearch_monitor [:filename] - Print progress of line searches
603: . -snes_linesearch_damping - The linesearch damping parameter, default is 1.0 (no damping)
604: . -snes_linesearch_norms - Turn on/off the linesearch norms computation (SNESLineSearchSetComputeNorms())
605: . -snes_linesearch_keeplambda - Keep the previous `lambda` as the initial guess
606: - -snes_linesearch_max_it - The number of iterations for iterative line searches
608: Level: intermediate
610: Notes:
611: This is typically called from within a `SNESSolve()` implementation in order to
612: help with convergence of the nonlinear method. Various `SNES` types use line searches
613: in different ways, but the overarching theme is that a line search is used to determine
614: an optimal damping parameter (that is `lambda`) of a step at each iteration of the method. Each
615: application of the line search may invoke `SNESComputeFunction()` several times, and
616: therefore may be fairly expensive.
618: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchGetLambda()`, `SNESLineSearchPreCheck()`, `SNESLineSearchPostCheck()`, `SNESSolve()`, `SNESComputeFunction()`, `SNESLineSearchSetComputeNorms()`,
619: `SNESLineSearchType`, `SNESLineSearchSetType()`
620: @*/
621: PetscErrorCode SNESLineSearchApply(SNESLineSearch linesearch, Vec X, Vec F, PetscReal *fnorm, Vec Y)
622: {
623: PetscFunctionBegin;
629: linesearch->result = SNES_LINESEARCH_SUCCEEDED;
631: linesearch->vec_sol = X;
632: linesearch->vec_update = Y;
633: linesearch->vec_func = F;
635: PetscCall(SNESLineSearchSetUp(linesearch));
637: if (!linesearch->keeplambda) linesearch->lambda = linesearch->damping; /* set the initial guess to lambda */
639: if (fnorm) linesearch->fnorm = *fnorm;
640: else PetscCall(VecNorm(F, NORM_2, &linesearch->fnorm));
642: PetscCall(PetscLogEventBegin(SNESLINESEARCH_Apply, linesearch, X, F, Y));
644: PetscUseTypeMethod(linesearch, apply);
646: PetscCall(PetscLogEventEnd(SNESLINESEARCH_Apply, linesearch, X, F, Y));
648: if (fnorm) *fnorm = linesearch->fnorm;
649: PetscFunctionReturn(PETSC_SUCCESS);
650: }
652: /*@
653: SNESLineSearchDestroy - Destroys the line search instance.
655: Collective
657: Input Parameter:
658: . linesearch - The line search context
660: Level: developer
662: Note:
663: The line search in `SNES` is automatically called on `SNESDestroy()` so this call is rarely needed
665: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchReset()`, `SNESDestroy()`
666: @*/
667: PetscErrorCode SNESLineSearchDestroy(SNESLineSearch *linesearch)
668: {
669: PetscFunctionBegin;
670: if (!*linesearch) PetscFunctionReturn(PETSC_SUCCESS);
672: if (--((PetscObject)*linesearch)->refct > 0) {
673: *linesearch = NULL;
674: PetscFunctionReturn(PETSC_SUCCESS);
675: }
676: PetscCall(PetscObjectSAWsViewOff((PetscObject)*linesearch));
677: PetscCall(SNESLineSearchReset(*linesearch));
678: PetscTryTypeMethod(*linesearch, destroy);
679: PetscCall(PetscViewerDestroy(&(*linesearch)->monitor));
680: PetscCall(SNESLineSearchMonitorCancel(*linesearch));
681: PetscCall(PetscHeaderDestroy(linesearch));
682: PetscFunctionReturn(PETSC_SUCCESS);
683: }
685: /*@
686: SNESLineSearchSetDefaultMonitor - Turns on/off printing useful information and debugging output about the line search.
688: Logically Collective
690: Input Parameters:
691: + linesearch - the linesearch object
692: - viewer - an `PETSCVIEWERASCII` `PetscViewer` or `NULL` to turn off monitor
694: Options Database Key:
695: . -snes_linesearch_monitor [:filename] - enables the monitor
697: Level: intermediate
699: Developer Notes:
700: This monitor is implemented differently than the other line search monitors that are set with
701: `SNESLineSearchMonitorSet()` since it is called in many locations of the line search routines to display aspects of the
702: line search that are not visible to the other monitors.
704: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `PETSCVIEWERASCII`, `SNESGetLineSearch()`, `SNESLineSearchGetDefaultMonitor()`, `PetscViewer`, `SNESLineSearchSetMonitor()`,
705: `SNESLineSearchMonitorSetFromOptions()`
706: @*/
707: PetscErrorCode SNESLineSearchSetDefaultMonitor(SNESLineSearch linesearch, PetscViewer viewer)
708: {
709: PetscFunctionBegin;
710: PetscCall(PetscViewerDestroy(&linesearch->monitor));
711: linesearch->monitor = viewer;
712: PetscFunctionReturn(PETSC_SUCCESS);
713: }
715: /*@
716: SNESLineSearchGetDefaultMonitor - Gets the `PetscViewer` instance for the default line search monitor that is turned on with `SNESLineSearchSetDefaultMonitor()`
718: Logically Collective
720: Input Parameter:
721: . linesearch - the line search context
723: Output Parameter:
724: . monitor - monitor context
726: Level: intermediate
728: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchSetDefaultMonitor()`, `PetscViewer`
729: @*/
730: PetscErrorCode SNESLineSearchGetDefaultMonitor(SNESLineSearch linesearch, PetscViewer *monitor)
731: {
732: PetscFunctionBegin;
734: *monitor = linesearch->monitor;
735: PetscFunctionReturn(PETSC_SUCCESS);
736: }
738: /*@C
739: SNESLineSearchMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated in the options database
741: Collective
743: Input Parameters:
744: + ls - `SNESLineSearch` object to monitor
745: . name - the monitor type
746: . help - message indicating what monitoring is done
747: . manual - manual page for the monitor
748: . monitor - the monitor function, must use `PetscViewerAndFormat` as its context
749: - monitorsetup - a function that is called once ONLY if the user selected this monitor that may set additional features of the `SNESLineSearch` or `PetscViewer`
751: Calling sequence of `monitor`:
752: + ls - `SNESLineSearch` object being monitored
753: - vf - a `PetscViewerAndFormat` struct that provides the `PetscViewer` and `PetscViewerFormat` being used
755: Calling sequence of `monitorsetup`:
756: + ls - `SNESLineSearch` object being monitored
757: - vf - a `PetscViewerAndFormat` struct that provides the `PetscViewer` and `PetscViewerFormat` being used
759: Level: advanced
761: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetMonitor()`, `PetscOptionsCreateViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
762: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`
763: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
764: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
765: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
766: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
767: `PetscOptionsFList()`, `PetscOptionsEList()`
768: @*/
769: PetscErrorCode SNESLineSearchMonitorSetFromOptions(SNESLineSearch ls, const char name[], const char help[], const char manual[], PetscErrorCode (*monitor)(SNESLineSearch ls, PetscViewerAndFormat *vf), PetscErrorCode (*monitorsetup)(SNESLineSearch ls, PetscViewerAndFormat *vf))
770: {
771: PetscViewer viewer;
772: PetscViewerFormat format;
773: PetscBool flg;
775: PetscFunctionBegin;
776: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)ls), ((PetscObject)ls)->options, ((PetscObject)ls)->prefix, name, &viewer, &format, &flg));
777: if (flg) {
778: PetscViewerAndFormat *vf;
779: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
780: PetscCall(PetscViewerDestroy(&viewer));
781: if (monitorsetup) PetscCall((*monitorsetup)(ls, vf));
782: PetscCall(SNESLineSearchMonitorSet(ls, (PetscErrorCode (*)(SNESLineSearch, void *))monitor, vf, (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy));
783: }
784: PetscFunctionReturn(PETSC_SUCCESS);
785: }
787: /*@
788: SNESLineSearchSetFromOptions - Sets options for the line search
790: Logically Collective
792: Input Parameter:
793: . linesearch - a `SNESLineSearch` line search context
795: Options Database Keys:
796: + -snes_linesearch_type <type> - basic (or equivalently none), `bt`, `secant`, `cp`, `nleqerr`, `bisection`, `shell`
797: . -snes_linesearch_order <order> - 1, 2, 3. Most types only support certain orders (`bt` supports 1, 2 or 3)
798: . -snes_linesearch_norms - Turn on/off the linesearch norms for the basic linesearch typem (`SNESLineSearchSetComputeNorms()`)
799: . -snes_linesearch_minlambda - The minimum `lambda`
800: . -snes_linesearch_maxlambda - The maximum `lambda`
801: . -snes_linesearch_rtol - Relative tolerance for iterative line searches
802: . -snes_linesearch_atol - Absolute tolerance for iterative line searches
803: . -snes_linesearch_ltol - Change in `lambda` tolerance for iterative line searches
804: . -snes_linesearch_max_it - The number of iterations for iterative line searches
805: . -snes_linesearch_monitor [:filename] - Print progress of line searches
806: . -snes_linesearch_monitor_solution_update [viewer:filename:format] - view each update tried by line search routine
807: . -snes_linesearch_damping - The linesearch damping parameter
808: . -snes_linesearch_keeplambda - Keep the previous `lambda` as the initial guess.
809: . -snes_linesearch_precheck_picard - Use precheck that speeds up convergence of picard method
810: - -snes_linesearch_precheck_picard_angle - Angle used in Picard precheck method
812: Level: intermediate
814: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchSetOrder()`, `SNESLineSearchSetType()`, `SNESLineSearchSetTolerances()`, `SNESLineSearchSetDamping()`, `SNESLineSearchPreCheckPicard()`,
815: `SNESLineSearchType`, `SNESLineSearchSetComputeNorms()`
816: @*/
817: PetscErrorCode SNESLineSearchSetFromOptions(SNESLineSearch linesearch)
818: {
819: const char *deft = SNESLINESEARCHBASIC;
820: char type[256];
821: PetscBool flg, set;
822: PetscViewer viewer;
824: PetscFunctionBegin;
825: PetscCall(SNESLineSearchRegisterAll());
827: PetscObjectOptionsBegin((PetscObject)linesearch);
828: if (((PetscObject)linesearch)->type_name) deft = ((PetscObject)linesearch)->type_name;
829: PetscCall(PetscOptionsFList("-snes_linesearch_type", "Linesearch type", "SNESLineSearchSetType", SNESLineSearchList, deft, type, 256, &flg));
830: if (flg) {
831: PetscCall(SNESLineSearchSetType(linesearch, type));
832: } else if (!((PetscObject)linesearch)->type_name) {
833: PetscCall(SNESLineSearchSetType(linesearch, deft));
834: }
836: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)linesearch), ((PetscObject)linesearch)->options, ((PetscObject)linesearch)->prefix, "-snes_linesearch_monitor", &viewer, NULL, &set));
837: if (set) PetscCall(SNESLineSearchSetDefaultMonitor(linesearch, viewer));
838: PetscCall(SNESLineSearchMonitorSetFromOptions(linesearch, "-snes_linesearch_monitor_solution_update", "View correction at each iteration", "SNESLineSearchMonitorSolutionUpdate", SNESLineSearchMonitorSolutionUpdate, NULL));
840: /* tolerances */
841: PetscCall(PetscOptionsReal("-snes_linesearch_minlambda", "Minimum lambda", "SNESLineSearchSetTolerances", linesearch->minlambda, &linesearch->minlambda, NULL));
842: PetscCall(PetscOptionsReal("-snes_linesearch_maxlambda", "Maximum lambda", "SNESLineSearchSetTolerances", linesearch->maxlambda, &linesearch->maxlambda, NULL));
843: PetscCall(PetscOptionsReal("-snes_linesearch_rtol", "Relative tolerance for iterative line search", "SNESLineSearchSetTolerances", linesearch->rtol, &linesearch->rtol, NULL));
844: PetscCall(PetscOptionsReal("-snes_linesearch_atol", "Absolute tolerance for iterative line search", "SNESLineSearchSetTolerances", linesearch->atol, &linesearch->atol, NULL));
845: PetscCall(PetscOptionsReal("-snes_linesearch_ltol", "Change in lambda tolerance for iterative line search", "SNESLineSearchSetTolerances", linesearch->ltol, &linesearch->ltol, NULL));
846: PetscCall(PetscOptionsInt("-snes_linesearch_max_it", "Maximum iterations for iterative line searches", "SNESLineSearchSetTolerances", linesearch->max_it, &linesearch->max_it, NULL));
848: /* deprecated options */
849: PetscCall(PetscOptionsDeprecated("-snes_linesearch_maxstep", "-snes_linesearch_maxlambda", "3.24.0", NULL));
851: /* damping parameters */
852: PetscCall(PetscOptionsReal("-snes_linesearch_damping", "Line search damping (and depending on chosen line search initial lambda guess)", "SNESLineSearchSetDamping", linesearch->damping, &linesearch->damping, NULL));
854: PetscCall(PetscOptionsBool("-snes_linesearch_keeplambda", "Use previous lambda as damping", "SNESLineSearchSetKeepLambda", linesearch->keeplambda, &linesearch->keeplambda, NULL));
856: /* precheck */
857: PetscCall(PetscOptionsBool("-snes_linesearch_precheck_picard", "Use a correction that sometimes improves convergence of Picard iteration", "SNESLineSearchPreCheckPicard", flg, &flg, &set));
858: if (set) {
859: if (flg) {
860: linesearch->precheck_picard_angle = 10.; /* correction only active if angle is less than 10 degrees */
862: PetscCall(PetscOptionsReal("-snes_linesearch_precheck_picard_angle", "Maximum angle at which to activate the correction", "none", linesearch->precheck_picard_angle, &linesearch->precheck_picard_angle, NULL));
863: PetscCall(SNESLineSearchSetPreCheck(linesearch, SNESLineSearchPreCheckPicard, &linesearch->precheck_picard_angle));
864: } else {
865: PetscCall(SNESLineSearchSetPreCheck(linesearch, NULL, NULL));
866: }
867: }
868: PetscCall(PetscOptionsInt("-snes_linesearch_order", "Order of approximation used in the line search", "SNESLineSearchSetOrder", linesearch->order, &linesearch->order, NULL));
869: PetscCall(PetscOptionsBool("-snes_linesearch_norms", "Compute final norms in line search", "SNESLineSearchSetComputeNorms", linesearch->norms, &linesearch->norms, NULL));
871: PetscTryTypeMethod(linesearch, setfromoptions, PetscOptionsObject);
873: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)linesearch, PetscOptionsObject));
874: PetscOptionsEnd();
875: PetscFunctionReturn(PETSC_SUCCESS);
876: }
878: /*@
879: SNESLineSearchView - Prints useful information about the line search
881: Logically Collective
883: Input Parameters:
884: + linesearch - line search context
885: - viewer - the `PetscViewer` to display the line search information to
887: Level: intermediate
889: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `PetscViewer`, `SNESLineSearchCreate()`
890: @*/
891: PetscErrorCode SNESLineSearchView(SNESLineSearch linesearch, PetscViewer viewer)
892: {
893: PetscBool isascii;
895: PetscFunctionBegin;
897: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)linesearch), &viewer));
899: PetscCheckSameComm(linesearch, 1, viewer, 2);
901: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
902: if (isascii) {
903: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)linesearch, viewer));
904: PetscCall(PetscViewerASCIIPushTab(viewer));
905: PetscTryTypeMethod(linesearch, view, viewer);
906: PetscCall(PetscViewerASCIIPopTab(viewer));
907: PetscCall(PetscViewerASCIIPrintf(viewer, " maxlambda=%e, minlambda=%e\n", (double)linesearch->maxlambda, (double)linesearch->minlambda));
908: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%e, absolute=%e, lambda=%e\n", (double)linesearch->rtol, (double)linesearch->atol, (double)linesearch->ltol));
909: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT "\n", linesearch->max_it));
910: if (linesearch->ops->precheck) {
911: if (linesearch->ops->precheck == SNESLineSearchPreCheckPicard) {
912: PetscCall(PetscViewerASCIIPrintf(viewer, " using precheck step to speed up Picard convergence\n"));
913: } else {
914: PetscCall(PetscViewerASCIIPrintf(viewer, " using user-defined precheck step\n"));
915: }
916: }
917: if (linesearch->ops->postcheck) PetscCall(PetscViewerASCIIPrintf(viewer, " using user-defined postcheck step\n"));
918: }
919: PetscFunctionReturn(PETSC_SUCCESS);
920: }
922: /*@
923: SNESLineSearchGetType - Gets the `SNESLinesearchType` of a `SNESLineSearch`
925: Logically Collective
927: Input Parameter:
928: . linesearch - the line search context
930: Output Parameter:
931: . type - The type of line search, or `NULL` if not set
933: Level: intermediate
935: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`, `SNESLineSearchSetType()`
936: @*/
937: PetscErrorCode SNESLineSearchGetType(SNESLineSearch linesearch, SNESLineSearchType *type)
938: {
939: PetscFunctionBegin;
941: PetscAssertPointer(type, 2);
942: *type = ((PetscObject)linesearch)->type_name;
943: PetscFunctionReturn(PETSC_SUCCESS);
944: }
946: /*@
947: SNESLineSearchSetType - Sets the `SNESLinesearchType` of a `SNESLineSearch` object to indicate the line search algorithm that should be used by a given `SNES` solver
949: Logically Collective
951: Input Parameters:
952: + linesearch - the line search context
953: - type - The type of line search to be used, see `SNESLineSearchType`
955: Options Database Key:
956: . -snes_linesearch_type <type> - basic (or equivalently none), bt, secant, cp, nleqerr, bisection, shell
958: Level: intermediate
960: Note:
961: The `SNESLineSearch` object is generally obtained with `SNESGetLineSearch()`
963: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`, `SNESLineSearchGetType()`,
964: `SNESGetLineSearch()`
965: @*/
966: PetscErrorCode SNESLineSearchSetType(SNESLineSearch linesearch, SNESLineSearchType type)
967: {
968: PetscBool match;
969: PetscErrorCode (*r)(SNESLineSearch);
971: PetscFunctionBegin;
973: PetscAssertPointer(type, 2);
975: PetscCall(PetscObjectTypeCompare((PetscObject)linesearch, type, &match));
976: if (match) PetscFunctionReturn(PETSC_SUCCESS);
978: PetscCall(PetscFunctionListFind(SNESLineSearchList, type, &r));
979: PetscCheck(r, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested Line Search type %s", type);
980: /* Destroy the previous private line search context */
981: PetscTryTypeMethod(linesearch, destroy);
982: linesearch->ops->destroy = NULL;
983: /* Reinitialize function pointers in SNESLineSearchOps structure */
984: linesearch->ops->apply = NULL;
985: linesearch->ops->view = NULL;
986: linesearch->ops->setfromoptions = NULL;
987: linesearch->ops->destroy = NULL;
989: PetscCall(PetscObjectChangeTypeName((PetscObject)linesearch, type));
990: PetscCall((*r)(linesearch));
991: PetscFunctionReturn(PETSC_SUCCESS);
992: }
994: /*@
995: SNESLineSearchSetSNES - Sets the `SNES` for the linesearch for function evaluation.
997: Input Parameters:
998: + linesearch - the line search context
999: - snes - The `SNES` instance
1001: Level: developer
1003: Note:
1004: This happens automatically when the line search is obtained/created with
1005: `SNESGetLineSearch()`. This routine is therefore mainly called within `SNES`
1006: implementations.
1008: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetSNES()`, `SNESLineSearchSetVecs()`
1009: @*/
1010: PetscErrorCode SNESLineSearchSetSNES(SNESLineSearch linesearch, SNES snes)
1011: {
1012: PetscFunctionBegin;
1015: linesearch->snes = snes;
1016: PetscFunctionReturn(PETSC_SUCCESS);
1017: }
1019: /*@
1020: SNESLineSearchGetSNES - Gets the `SNES` instance associated with the line search.
1022: Not Collective
1024: Input Parameter:
1025: . linesearch - the line search context
1027: Output Parameter:
1028: . snes - The `SNES` instance
1030: Level: developer
1032: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESType`, `SNESLineSearchSetVecs()`
1033: @*/
1034: PetscErrorCode SNESLineSearchGetSNES(SNESLineSearch linesearch, SNES *snes)
1035: {
1036: PetscFunctionBegin;
1038: PetscAssertPointer(snes, 2);
1039: *snes = linesearch->snes;
1040: PetscFunctionReturn(PETSC_SUCCESS);
1041: }
1043: /*@
1044: SNESLineSearchGetLambda - Gets the last line search `lambda` used
1046: Not Collective
1048: Input Parameter:
1049: . linesearch - the line search context
1051: Output Parameter:
1052: . lambda - The last `lambda` (scaling of the solution udpate) computed during `SNESLineSearchApply()`
1054: Level: advanced
1056: Note:
1057: This is useful in methods where the solver is ill-scaled and
1058: requires some adaptive notion of the difference in scale between the
1059: solution and the function. For instance, `SNESQN` may be scaled by the
1060: line search `lambda` using the argument -snes_qn_scaling ls.
1062: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetLambda()`, `SNESLineSearchGetDamping()`, `SNESLineSearchApply()`
1063: @*/
1064: PetscErrorCode SNESLineSearchGetLambda(SNESLineSearch linesearch, PetscReal *lambda)
1065: {
1066: PetscFunctionBegin;
1068: PetscAssertPointer(lambda, 2);
1069: *lambda = linesearch->lambda;
1070: PetscFunctionReturn(PETSC_SUCCESS);
1071: }
1073: /*@
1074: SNESLineSearchSetLambda - Sets the line search `lambda` (scaling of the solution update)
1076: Input Parameters:
1077: + linesearch - line search context
1078: - lambda - The `lambda` to use
1080: Level: advanced
1082: Note:
1083: This routine is typically used within implementations of `SNESLineSearchApply()`
1084: to set the final `lambda`. This routine (and `SNESLineSearchGetLambda()`) were
1085: added to facilitate Quasi-Newton methods that use the previous `lambda`
1086: as an inner scaling parameter.
1088: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetLambda()`
1089: @*/
1090: PetscErrorCode SNESLineSearchSetLambda(SNESLineSearch linesearch, PetscReal lambda)
1091: {
1092: PetscFunctionBegin;
1094: linesearch->lambda = lambda;
1095: PetscFunctionReturn(PETSC_SUCCESS);
1096: }
1098: /*@
1099: SNESLineSearchGetTolerances - Gets the tolerances for the line search.
1101: Not Collective
1103: Input Parameter:
1104: . linesearch - the line search context
1106: Output Parameters:
1107: + minlambda - The minimum `lambda` allowed
1108: . maxlambda - The maximum `lambda` allowed
1109: . rtol - The relative tolerance for iterative line searches
1110: . atol - The absolute tolerance for iterative line searches
1111: . ltol - The change in `lambda` tolerance for iterative line searches
1112: - max_it - The maximum number of iterations of the line search
1114: Level: intermediate
1116: Note:
1117: Different line searches may implement these parameters slightly differently as
1118: the type requires.
1120: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetTolerances()`
1121: @*/
1122: PetscErrorCode SNESLineSearchGetTolerances(SNESLineSearch linesearch, PetscReal *minlambda, PetscReal *maxlambda, PetscReal *rtol, PetscReal *atol, PetscReal *ltol, PetscInt *max_it)
1123: {
1124: PetscFunctionBegin;
1126: if (minlambda) {
1127: PetscAssertPointer(minlambda, 2);
1128: *minlambda = linesearch->minlambda;
1129: }
1130: if (maxlambda) {
1131: PetscAssertPointer(maxlambda, 3);
1132: *maxlambda = linesearch->maxlambda;
1133: }
1134: if (rtol) {
1135: PetscAssertPointer(rtol, 4);
1136: *rtol = linesearch->rtol;
1137: }
1138: if (atol) {
1139: PetscAssertPointer(atol, 5);
1140: *atol = linesearch->atol;
1141: }
1142: if (ltol) {
1143: PetscAssertPointer(ltol, 6);
1144: *ltol = linesearch->ltol;
1145: }
1146: if (max_it) {
1147: PetscAssertPointer(max_it, 7);
1148: *max_it = linesearch->max_it;
1149: }
1150: PetscFunctionReturn(PETSC_SUCCESS);
1151: }
1153: /*@
1154: SNESLineSearchSetTolerances - Sets the tolerances for the linesearch.
1156: Collective
1158: Input Parameters:
1159: + linesearch - the line search context
1160: . minlambda - The minimum `lambda` allowed
1161: . maxlambda - The maximum `lambda` allowed
1162: . rtol - The relative tolerance for iterative line searches
1163: . atol - The absolute tolerance for iterative line searches
1164: . ltol - The change in `lambda` tolerance for iterative line searches
1165: - max_it - The maximum number of iterations of the line search
1167: Options Database Keys:
1168: + -snes_linesearch_minlambda - The minimum `lambda` allowed
1169: . -snes_linesearch_maxlambda - The maximum `lambda` allowed
1170: . -snes_linesearch_rtol - Relative tolerance for iterative line searches
1171: . -snes_linesearch_atol - Absolute tolerance for iterative line searches
1172: . -snes_linesearch_ltol - Change in `lambda` tolerance for iterative line searches
1173: - -snes_linesearch_max_it - The number of iterations for iterative line searches
1175: Level: intermediate
1177: Note:
1178: The user may choose to not set any of the tolerances using `PETSC_DEFAULT` in place of an argument.
1180: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetTolerances()`
1181: @*/
1182: PetscErrorCode SNESLineSearchSetTolerances(SNESLineSearch linesearch, PetscReal minlambda, PetscReal maxlambda, PetscReal rtol, PetscReal atol, PetscReal ltol, PetscInt max_it)
1183: {
1184: PetscFunctionBegin;
1193: if (minlambda != (PetscReal)PETSC_DEFAULT) {
1194: PetscCheck(minlambda >= 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Minimum lambda %14.12e must be non-negative", (double)minlambda);
1195: PetscCheck(minlambda < maxlambda, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Minimum lambda %14.12e must be smaller than maximum lambda %14.12e", (double)minlambda, (double)maxlambda);
1196: linesearch->minlambda = minlambda;
1197: }
1199: if (maxlambda != (PetscReal)PETSC_DEFAULT) {
1200: PetscCheck(maxlambda > 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Maximum lambda %14.12e must be positive", (double)maxlambda);
1201: linesearch->maxlambda = maxlambda;
1202: }
1204: if (rtol != (PetscReal)PETSC_DEFAULT) {
1205: PetscCheck(rtol >= 0.0 && rtol < 1.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Relative tolerance %14.12e must be non-negative and less than 1.0", (double)rtol);
1206: linesearch->rtol = rtol;
1207: }
1209: if (atol != (PetscReal)PETSC_DEFAULT) {
1210: PetscCheck(atol >= 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %14.12e must be non-negative", (double)atol);
1211: linesearch->atol = atol;
1212: }
1214: if (ltol != (PetscReal)PETSC_DEFAULT) {
1215: PetscCheck(ltol >= 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Lambda tolerance %14.12e must be non-negative", (double)ltol);
1216: linesearch->ltol = ltol;
1217: }
1219: if (max_it != PETSC_DEFAULT) {
1220: PetscCheck(max_it >= 0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", max_it);
1221: linesearch->max_it = max_it;
1222: }
1223: PetscFunctionReturn(PETSC_SUCCESS);
1224: }
1226: /*@
1227: SNESLineSearchGetDamping - Gets the line search damping parameter.
1229: Input Parameter:
1230: . linesearch - the line search context
1232: Output Parameter:
1233: . damping - The damping parameter
1235: Level: advanced
1237: .seealso: [](ch_snes), `SNES`, `SNESLineSearchGetStepTolerance()`, `SNESQN`
1238: @*/
1239: PetscErrorCode SNESLineSearchGetDamping(SNESLineSearch linesearch, PetscReal *damping)
1240: {
1241: PetscFunctionBegin;
1243: PetscAssertPointer(damping, 2);
1244: *damping = linesearch->damping;
1245: PetscFunctionReturn(PETSC_SUCCESS);
1246: }
1248: /*@
1249: SNESLineSearchSetDamping - Sets the line search damping parameter.
1251: Input Parameters:
1252: + linesearch - the line search context
1253: - damping - The damping parameter
1255: Options Database Key:
1256: . -snes_linesearch_damping <damping> - the damping value
1258: Level: intermediate
1260: Note:
1261: The `SNESLINESEARCHNONE` line search merely takes the update step scaled by the damping parameter.
1262: The use of the damping parameter in the `SNESLINESEARCHSECANT` and `SNESLINESEARCHCP` line searches is much more subtle;
1263: it is used as a starting point for the secant method. Depending on the choice for `maxlambda`,
1264: the eventual `lambda` may be greater than the damping parameter however.
1265: For `SNESLINESEARCHBISECTION` and `SNESLINESEARCHBT` the damping is instead used as the initial guess,
1266: below which the line search will not go. Hence, it is the maximum possible value for `lambda`.
1268: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetDamping()`
1269: @*/
1270: PetscErrorCode SNESLineSearchSetDamping(SNESLineSearch linesearch, PetscReal damping)
1271: {
1272: PetscFunctionBegin;
1274: linesearch->damping = damping;
1275: PetscFunctionReturn(PETSC_SUCCESS);
1276: }
1278: /*@
1279: SNESLineSearchGetOrder - Gets the line search approximation order.
1281: Input Parameter:
1282: . linesearch - the line search context
1284: Output Parameter:
1285: . order - The order
1287: Level: intermediate
1289: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetOrder()`
1290: @*/
1291: PetscErrorCode SNESLineSearchGetOrder(SNESLineSearch linesearch, PetscInt *order)
1292: {
1293: PetscFunctionBegin;
1295: PetscAssertPointer(order, 2);
1296: *order = linesearch->order;
1297: PetscFunctionReturn(PETSC_SUCCESS);
1298: }
1300: /*@
1301: SNESLineSearchSetOrder - Sets the maximum order of the polynomial fit used in the line search
1303: Input Parameters:
1304: + linesearch - the line search context
1305: - order - The order
1307: Level: intermediate
1309: Values for `order`\:
1310: + 1 or `SNES_LINESEARCH_ORDER_LINEAR` - linear order
1311: . 2 or `SNES_LINESEARCH_ORDER_QUADRATIC` - quadratic order
1312: - 3 or `SNES_LINESEARCH_ORDER_CUBIC` - cubic order
1314: Options Database Key:
1315: . -snes_linesearch_order <order> - 1, 2, 3. Most types only support certain orders (`SNESLINESEARCHBT` supports 2 or 3)
1317: Note:
1318: These orders are supported by `SNESLINESEARCHBT` and `SNESLINESEARCHCP`
1320: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetOrder()`, `SNESLineSearchSetDamping()`
1321: @*/
1322: PetscErrorCode SNESLineSearchSetOrder(SNESLineSearch linesearch, PetscInt order)
1323: {
1324: PetscFunctionBegin;
1326: linesearch->order = order;
1327: PetscFunctionReturn(PETSC_SUCCESS);
1328: }
1330: /*@
1331: SNESLineSearchGetNorms - Gets the norms for the current solution `X`, the current update `Y`, and the current function value `F`.
1333: Not Collective
1335: Input Parameter:
1336: . linesearch - the line search context
1338: Output Parameters:
1339: + xnorm - The norm of the current solution
1340: . fnorm - The norm of the current function, this is the `norm(function(X))` where `X` is the current solution.
1341: - ynorm - The norm of the current update (after scaling by the linesearch computed `lambda`)
1343: Level: developer
1345: Notes:
1346: Some values may not be up-to-date at particular points in the code.
1348: This, in combination with `SNESLineSearchSetNorms()`, allow the line search and the `SNESSolve_XXX()` to share
1349: computed values.
1351: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetNorms()`, `SNESLineSearchGetVecs()`
1352: @*/
1353: PetscErrorCode SNESLineSearchGetNorms(SNESLineSearch linesearch, PetscReal *xnorm, PetscReal *fnorm, PetscReal *ynorm)
1354: {
1355: PetscFunctionBegin;
1357: if (xnorm) *xnorm = linesearch->xnorm;
1358: if (fnorm) *fnorm = linesearch->fnorm;
1359: if (ynorm) *ynorm = linesearch->ynorm;
1360: PetscFunctionReturn(PETSC_SUCCESS);
1361: }
1363: /*@
1364: SNESLineSearchSetNorms - Sets the computed norms for the current solution `X`, the current update `Y`, and the current function value `F`.
1366: Collective
1368: Input Parameters:
1369: + linesearch - the line search context
1370: . xnorm - The norm of the current solution
1371: . fnorm - The norm of the current function, this is the `norm(function(X))` where `X` is the current solution
1372: - ynorm - The norm of the current update (after scaling by the linesearch computed `lambda`)
1374: Level: developer
1376: Note:
1377: This is called by the line search routines to store the values they have just computed
1379: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetNorms()`, `SNESLineSearchSetVecs()`
1380: @*/
1381: PetscErrorCode SNESLineSearchSetNorms(SNESLineSearch linesearch, PetscReal xnorm, PetscReal fnorm, PetscReal ynorm)
1382: {
1383: PetscFunctionBegin;
1385: linesearch->xnorm = xnorm;
1386: linesearch->fnorm = fnorm;
1387: linesearch->ynorm = ynorm;
1388: PetscFunctionReturn(PETSC_SUCCESS);
1389: }
1391: /*@
1392: SNESLineSearchComputeNorms - Explicitly computes the norms of the current solution `X`, the current update `Y`, and the current function value `F`.
1394: Input Parameter:
1395: . linesearch - the line search context
1397: Options Database Key:
1398: . -snes_linesearch_norms - turn norm computation on or off
1400: Level: intermediate
1402: Developer Note:
1403: The options database key is misnamed. It should be -snes_linesearch_compute_norms
1405: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetNorms`, `SNESLineSearchSetNorms()`, `SNESLineSearchSetComputeNorms()`
1406: @*/
1407: PetscErrorCode SNESLineSearchComputeNorms(SNESLineSearch linesearch)
1408: {
1409: SNES snes;
1411: PetscFunctionBegin;
1412: if (linesearch->norms) {
1413: if (linesearch->ops->vinorm) {
1414: PetscCall(SNESLineSearchGetSNES(linesearch, &snes));
1415: PetscCall(VecNorm(linesearch->vec_sol, NORM_2, &linesearch->xnorm));
1416: PetscCall(VecNorm(linesearch->vec_update, NORM_2, &linesearch->ynorm));
1417: PetscCall((*linesearch->ops->vinorm)(snes, linesearch->vec_func, linesearch->vec_sol, &linesearch->fnorm));
1418: } else {
1419: PetscCall(VecNormBegin(linesearch->vec_func, NORM_2, &linesearch->fnorm));
1420: PetscCall(VecNormBegin(linesearch->vec_sol, NORM_2, &linesearch->xnorm));
1421: PetscCall(VecNormBegin(linesearch->vec_update, NORM_2, &linesearch->ynorm));
1422: PetscCall(VecNormEnd(linesearch->vec_func, NORM_2, &linesearch->fnorm));
1423: PetscCall(VecNormEnd(linesearch->vec_sol, NORM_2, &linesearch->xnorm));
1424: PetscCall(VecNormEnd(linesearch->vec_update, NORM_2, &linesearch->ynorm));
1425: }
1426: }
1427: PetscFunctionReturn(PETSC_SUCCESS);
1428: }
1430: /*@
1431: SNESLineSearchSetComputeNorms - Turns on or off the computation of final norms in the line search.
1433: Input Parameters:
1434: + linesearch - the line search context
1435: - flg - indicates whether or not to compute norms
1437: Options Database Key:
1438: . -snes_linesearch_norms <true> - Turns on/off computation of the norms for basic (none) `SNESLINESEARCHBASIC` line search
1440: Level: intermediate
1442: Note:
1443: This is most relevant to the `SNESLINESEARCHBASIC` (or equivalently `SNESLINESEARCHNONE`) line search type since most line searches have a stopping criteria involving the norm.
1445: Developer Note:
1446: The options database key is misnamed. It should be -snes_linesearch_compute_norms
1448: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetNorms()`, `SNESLineSearchSetNorms()`, `SNESLineSearchComputeNorms()`, `SNESLINESEARCHBASIC`
1449: @*/
1450: PetscErrorCode SNESLineSearchSetComputeNorms(SNESLineSearch linesearch, PetscBool flg)
1451: {
1452: PetscFunctionBegin;
1453: linesearch->norms = flg;
1454: PetscFunctionReturn(PETSC_SUCCESS);
1455: }
1457: /*@
1458: SNESLineSearchGetVecs - Gets the vectors from the `SNESLineSearch` context
1460: Not Collective but the vectors are parallel
1462: Input Parameter:
1463: . linesearch - the line search context
1465: Output Parameters:
1466: + X - Solution vector
1467: . F - Function vector
1468: . Y - Search direction vector
1469: . W - Solution work vector
1470: - G - Function work vector
1472: Level: advanced
1474: Notes:
1475: At the beginning of a line search application, `X` should contain a
1476: solution and the vector `F` the function computed at `X`. At the end of the
1477: line search application, `X` should contain the new solution, and `F` the
1478: function evaluated at the new solution.
1480: These vectors are owned by the `SNESLineSearch` and should not be destroyed by the caller
1482: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetNorms()`, `SNESLineSearchSetVecs()`
1483: @*/
1484: PetscErrorCode SNESLineSearchGetVecs(SNESLineSearch linesearch, Vec *X, Vec *F, Vec *Y, Vec *W, Vec *G)
1485: {
1486: PetscFunctionBegin;
1488: if (X) {
1489: PetscAssertPointer(X, 2);
1490: *X = linesearch->vec_sol;
1491: }
1492: if (F) {
1493: PetscAssertPointer(F, 3);
1494: *F = linesearch->vec_func;
1495: }
1496: if (Y) {
1497: PetscAssertPointer(Y, 4);
1498: *Y = linesearch->vec_update;
1499: }
1500: if (W) {
1501: PetscAssertPointer(W, 5);
1502: *W = linesearch->vec_sol_new;
1503: }
1504: if (G) {
1505: PetscAssertPointer(G, 6);
1506: *G = linesearch->vec_func_new;
1507: }
1508: PetscFunctionReturn(PETSC_SUCCESS);
1509: }
1511: /*@
1512: SNESLineSearchSetVecs - Sets the vectors on the `SNESLineSearch` context
1514: Logically Collective
1516: Input Parameters:
1517: + linesearch - the line search context
1518: . X - Solution vector
1519: . F - Function vector
1520: . Y - Search direction vector
1521: . W - Solution work vector
1522: - G - Function work vector
1524: Level: developer
1526: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetNorms()`, `SNESLineSearchGetVecs()`
1527: @*/
1528: PetscErrorCode SNESLineSearchSetVecs(SNESLineSearch linesearch, Vec X, Vec F, Vec Y, Vec W, Vec G)
1529: {
1530: PetscFunctionBegin;
1532: if (X) {
1534: linesearch->vec_sol = X;
1535: }
1536: if (F) {
1538: linesearch->vec_func = F;
1539: }
1540: if (Y) {
1542: linesearch->vec_update = Y;
1543: }
1544: if (W) {
1546: linesearch->vec_sol_new = W;
1547: }
1548: if (G) {
1550: linesearch->vec_func_new = G;
1551: }
1552: PetscFunctionReturn(PETSC_SUCCESS);
1553: }
1555: /*@
1556: SNESLineSearchAppendOptionsPrefix - Appends to the prefix used for searching for all
1557: `SNESLineSearch` options in the database.
1559: Logically Collective
1561: Input Parameters:
1562: + linesearch - the `SNESLineSearch` context
1563: - prefix - the prefix to prepend to all option names
1565: Level: advanced
1567: Note:
1568: A hyphen (-) must NOT be given at the beginning of the prefix name.
1569: The first character of all runtime options is AUTOMATICALLY the hyphen.
1571: .seealso: [](ch_snes), `SNES`, `SNESLineSearch()`, `SNESLineSearchSetFromOptions()`, `SNESGetOptionsPrefix()`
1572: @*/
1573: PetscErrorCode SNESLineSearchAppendOptionsPrefix(SNESLineSearch linesearch, const char prefix[])
1574: {
1575: PetscFunctionBegin;
1577: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)linesearch, prefix));
1578: PetscFunctionReturn(PETSC_SUCCESS);
1579: }
1581: /*@
1582: SNESLineSearchGetOptionsPrefix - Gets the prefix used for searching for all
1583: SNESLineSearch options in the database.
1585: Not Collective
1587: Input Parameter:
1588: . linesearch - the `SNESLineSearch` context
1590: Output Parameter:
1591: . prefix - pointer to the prefix string used
1593: Level: advanced
1595: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESAppendOptionsPrefix()`
1596: @*/
1597: PetscErrorCode SNESLineSearchGetOptionsPrefix(SNESLineSearch linesearch, const char *prefix[])
1598: {
1599: PetscFunctionBegin;
1601: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)linesearch, prefix));
1602: PetscFunctionReturn(PETSC_SUCCESS);
1603: }
1605: /*@C
1606: SNESLineSearchSetWorkVecs - Sets work vectors for the line search.
1608: Input Parameters:
1609: + linesearch - the `SNESLineSearch` context
1610: - nwork - the number of work vectors
1612: Level: developer
1614: Developer Note:
1615: This is called from within the set up routines for each of the line search types `SNESLineSearchType`
1617: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESSetWorkVecs()`
1618: @*/
1619: PetscErrorCode SNESLineSearchSetWorkVecs(SNESLineSearch linesearch, PetscInt nwork)
1620: {
1621: PetscFunctionBegin;
1622: PetscCheck(linesearch->vec_sol, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_USER, "Cannot get linesearch work-vectors without setting a solution vec!");
1623: PetscCall(VecDuplicateVecs(linesearch->vec_sol, nwork, &linesearch->work));
1624: PetscFunctionReturn(PETSC_SUCCESS);
1625: }
1627: /*@
1628: SNESLineSearchGetReason - Gets the success/failure status of the last line search application
1630: Input Parameter:
1631: . linesearch - the line search context
1633: Output Parameter:
1634: . result - The success or failure status
1636: Level: developer
1638: Note:
1639: This is typically called after `SNESLineSearchApply()` in order to determine if the line search failed
1640: (and set into the `SNES` convergence accordingly).
1642: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetReason()`, `SNESLineSearchReason`
1643: @*/
1644: PetscErrorCode SNESLineSearchGetReason(SNESLineSearch linesearch, SNESLineSearchReason *result)
1645: {
1646: PetscFunctionBegin;
1648: PetscAssertPointer(result, 2);
1649: *result = linesearch->result;
1650: PetscFunctionReturn(PETSC_SUCCESS);
1651: }
1653: /*@
1654: SNESLineSearchSetReason - Sets the success/failure status of the line search application
1656: Logically Collective; No Fortran Support
1658: Input Parameters:
1659: + linesearch - the line search context
1660: - result - The success or failure status
1662: Level: developer
1664: Note:
1665: This is typically called in a `SNESLineSearchType` implementation of `SNESLineSearchApply()` or a `SNESLINESEARCHSHELL` implementation to set
1666: the success or failure of the line search method.
1668: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchReason`, `SNESLineSearchGetSResult()`
1669: @*/
1670: PetscErrorCode SNESLineSearchSetReason(SNESLineSearch linesearch, SNESLineSearchReason result)
1671: {
1672: PetscFunctionBegin;
1674: linesearch->result = result;
1675: PetscFunctionReturn(PETSC_SUCCESS);
1676: }
1678: // PetscClangLinter pragma disable: -fdoc-param-list-func-parameter-documentation
1679: /*@C
1680: SNESLineSearchSetVIFunctions - Sets VI-specific functions for line search computation.
1682: Logically Collective
1684: Input Parameters:
1685: + linesearch - the linesearch object
1686: . projectfunc - function for projecting the function to the bounds, see `SNESLineSearchVIProjectFn` for calling sequence
1687: . normfunc - function for computing the norm of an active set, see `SNESLineSearchVINormFn` for calling sequence
1688: - dirderivfunc - function for computing the directional derivative of an active set, see `SNESLineSearchVIDirDerivFn` for calling sequence
1690: Level: advanced
1692: Notes:
1693: The VI solvers require projection of the solution to the feasible set. `projectfunc` should implement this.
1695: The VI solvers require special evaluation of the function norm such that the norm is only calculated
1696: on the inactive set. This should be implemented by `normfunc`.
1698: The VI solvers further require special evaluation of the directional derivative (when assuming that there exists some $G(x)$
1699: for which the `SNESFunctionFn` $F(x) = grad G(x)$) such that it is only calculated on the inactive set.
1700: This should be implemented by `dirderivfunc`.
1702: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetVIFunctions()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchSetPreCheck()`,
1703: `SNESLineSearchVIProjectFn`, `SNESLineSearchVINormFn`, `SNESLineSearchVIDirDerivFn`
1704: @*/
1705: PetscErrorCode SNESLineSearchSetVIFunctions(SNESLineSearch linesearch, SNESLineSearchVIProjectFn *projectfunc, SNESLineSearchVINormFn *normfunc, SNESLineSearchVIDirDerivFn *dirderivfunc)
1706: {
1707: PetscFunctionBegin;
1709: if (projectfunc) linesearch->ops->viproject = projectfunc;
1710: if (normfunc) linesearch->ops->vinorm = normfunc;
1711: if (dirderivfunc) linesearch->ops->vidirderiv = dirderivfunc;
1712: PetscFunctionReturn(PETSC_SUCCESS);
1713: }
1715: /*@C
1716: SNESLineSearchGetVIFunctions - Sets VI-specific functions for line search computation.
1718: Not Collective
1720: Input Parameter:
1721: . linesearch - the line search context, obtain with `SNESGetLineSearch()`
1723: Output Parameters:
1724: + projectfunc - function for projecting the function to the bounds, see `SNESLineSearchVIProjectFn` for calling sequence
1725: . normfunc - function for computing the norm of an active set, see `SNESLineSearchVINormFn ` for calling sequence
1726: - dirderivfunc - function for computing the directional derivative of an active set, see `SNESLineSearchVIDirDerivFn` for calling sequence
1728: Level: advanced
1730: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetVIFunctions()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchGetPreCheck()`,
1731: `SNESLineSearchVIProjectFn`, `SNESLineSearchVINormFn`
1732: @*/
1733: PetscErrorCode SNESLineSearchGetVIFunctions(SNESLineSearch linesearch, SNESLineSearchVIProjectFn **projectfunc, SNESLineSearchVINormFn **normfunc, SNESLineSearchVIDirDerivFn **dirderivfunc)
1734: {
1735: PetscFunctionBegin;
1736: if (projectfunc) *projectfunc = linesearch->ops->viproject;
1737: if (normfunc) *normfunc = linesearch->ops->vinorm;
1738: if (dirderivfunc) *dirderivfunc = linesearch->ops->vidirderiv;
1739: PetscFunctionReturn(PETSC_SUCCESS);
1740: }
1742: /*@C
1743: SNESLineSearchRegister - register a line search type `SNESLineSearchType`
1745: Logically Collective, No Fortran Support
1747: Input Parameters:
1748: + sname - name of the `SNESLineSearchType()`
1749: - function - the creation function for that type
1751: Calling sequence of `function`:
1752: . ls - the line search context
1754: Level: advanced
1756: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchType`, `SNESLineSearchSetType()`
1757: @*/
1758: PetscErrorCode SNESLineSearchRegister(const char sname[], PetscErrorCode (*function)(SNESLineSearch ls))
1759: {
1760: PetscFunctionBegin;
1761: PetscCall(SNESInitializePackage());
1762: PetscCall(PetscFunctionListAdd(&SNESLineSearchList, sname, function));
1763: PetscFunctionReturn(PETSC_SUCCESS);
1764: }