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`)
83: Calling sequence of `f`:
84: + ls - the `SNESLineSearch` context
85: - mctx - [optional] user-defined context for private data for the monitor routine
87: Calling sequence of `monitordestroy`:
88: . mctx - [optional] user-defined context for private data for the monitor routine
90: Level: intermediate
92: Note:
93: Several different monitoring routines may be set by calling
94: `SNESLineSearchMonitorSet()` multiple times; all will be called in the
95: order in which they were set.
97: Fortran Note:
98: Only a single monitor function can be set for each `SNESLineSearch` object
100: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchMonitorDefault()`, `SNESLineSearchMonitorCancel()`
101: @*/
102: PetscErrorCode SNESLineSearchMonitorSet(SNESLineSearch ls, PetscErrorCode (*f)(SNESLineSearch ls, void *mctx), void *mctx, PetscErrorCode (*monitordestroy)(void **mctx))
103: {
104: PetscInt i;
105: PetscBool identical;
107: PetscFunctionBegin;
109: for (i = 0; i < ls->numbermonitors; i++) {
110: PetscCall(PetscMonitorCompare((PetscErrorCode(*)(void))f, mctx, monitordestroy, (PetscErrorCode(*)(void))ls->monitorftns[i], ls->monitorcontext[i], ls->monitordestroy[i], &identical));
111: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
112: }
113: PetscCheck(ls->numbermonitors < MAXSNESLSMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
114: ls->monitorftns[ls->numbermonitors] = f;
115: ls->monitordestroy[ls->numbermonitors] = monitordestroy;
116: ls->monitorcontext[ls->numbermonitors++] = (void *)mctx;
117: PetscFunctionReturn(PETSC_SUCCESS);
118: }
120: /*@C
121: SNESLineSearchMonitorSolutionUpdate - Monitors each update of the function value the linesearch tries
123: Collective
125: Input Parameters:
126: + ls - the `SNESLineSearch` object
127: - vf - the context for the monitor, in this case it is an `PetscViewerAndFormat`
129: Options Database Key:
130: . -snes_linesearch_monitor_solution_update [viewer:filename:format] - view each update tried by line search routine
132: Level: developer
134: This is not normally called directly but is passed to `SNESLineSearchMonitorSet()`
136: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchMonitorSet()`, `SNESMonitorSolution()`
137: @*/
138: PetscErrorCode SNESLineSearchMonitorSolutionUpdate(SNESLineSearch ls, PetscViewerAndFormat *vf)
139: {
140: PetscViewer viewer = vf->viewer;
141: Vec Y, W, G;
143: PetscFunctionBegin;
144: PetscCall(SNESLineSearchGetVecs(ls, NULL, NULL, &Y, &W, &G));
145: PetscCall(PetscViewerPushFormat(viewer, vf->format));
146: PetscCall(PetscViewerASCIIPrintf(viewer, "LineSearch attempted update to solution \n"));
147: PetscCall(VecView(Y, viewer));
148: PetscCall(PetscViewerASCIIPrintf(viewer, "LineSearch attempted new solution \n"));
149: PetscCall(VecView(W, viewer));
150: PetscCall(PetscViewerASCIIPrintf(viewer, "LineSearch attempted updated function value\n"));
151: PetscCall(VecView(G, viewer));
152: PetscCall(PetscViewerPopFormat(viewer));
153: PetscFunctionReturn(PETSC_SUCCESS);
154: }
156: /*@
157: SNESLineSearchCreate - Creates a `SNESLineSearch` context.
159: Logically Collective
161: Input Parameter:
162: . comm - MPI communicator for the line search (typically from the associated `SNES` context).
164: Output Parameter:
165: . outlinesearch - the new line search context
167: Level: developer
169: Note:
170: The preferred calling sequence is to use `SNESGetLineSearch()` to acquire the `SNESLineSearch` instance
171: already associated with the `SNES`.
173: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `LineSearchDestroy()`, `SNESGetLineSearch()`
174: @*/
175: PetscErrorCode SNESLineSearchCreate(MPI_Comm comm, SNESLineSearch *outlinesearch)
176: {
177: SNESLineSearch linesearch;
179: PetscFunctionBegin;
180: PetscAssertPointer(outlinesearch, 2);
181: PetscCall(SNESInitializePackage());
182: *outlinesearch = NULL;
184: PetscCall(PetscHeaderCreate(linesearch, SNESLINESEARCH_CLASSID, "SNESLineSearch", "Linesearch", "SNESLineSearch", comm, SNESLineSearchDestroy, SNESLineSearchView));
186: linesearch->vec_sol_new = NULL;
187: linesearch->vec_func_new = NULL;
188: linesearch->vec_sol = NULL;
189: linesearch->vec_func = NULL;
190: linesearch->vec_update = NULL;
192: linesearch->lambda = 1.0;
193: linesearch->fnorm = 1.0;
194: linesearch->ynorm = 1.0;
195: linesearch->xnorm = 1.0;
196: linesearch->result = SNES_LINESEARCH_SUCCEEDED;
197: linesearch->norms = PETSC_TRUE;
198: linesearch->keeplambda = PETSC_FALSE;
199: linesearch->damping = 1.0;
200: linesearch->maxstep = 1e8;
201: linesearch->steptol = 1e-12;
202: linesearch->rtol = 1e-8;
203: linesearch->atol = 1e-15;
204: linesearch->ltol = 1e-8;
205: linesearch->precheckctx = NULL;
206: linesearch->postcheckctx = NULL;
207: linesearch->max_its = 1;
208: linesearch->setupcalled = PETSC_FALSE;
209: linesearch->monitor = NULL;
210: *outlinesearch = linesearch;
211: PetscFunctionReturn(PETSC_SUCCESS);
212: }
214: /*@
215: SNESLineSearchSetUp - Prepares the line search for being applied by allocating
216: any required vectors.
218: Collective
220: Input Parameter:
221: . linesearch - The `SNESLineSearch` instance.
223: Level: advanced
225: Note:
226: For most cases, this needn't be called by users or outside of `SNESLineSearchApply()`.
227: The only current case where this is called outside of this is for the VI
228: solvers, which modify the solution and work vectors before the first call
229: of `SNESLineSearchApply()`, requiring the `SNESLineSearch` work vectors to be
230: allocated upfront.
232: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchReset()`
233: @*/
234: PetscErrorCode SNESLineSearchSetUp(SNESLineSearch linesearch)
235: {
236: PetscFunctionBegin;
237: if (!((PetscObject)linesearch)->type_name) PetscCall(SNESLineSearchSetType(linesearch, SNESLINESEARCHBASIC));
238: if (!linesearch->setupcalled) {
239: if (!linesearch->vec_sol_new) PetscCall(VecDuplicate(linesearch->vec_sol, &linesearch->vec_sol_new));
240: if (!linesearch->vec_func_new) PetscCall(VecDuplicate(linesearch->vec_sol, &linesearch->vec_func_new));
241: if (linesearch->ops->setup) PetscUseTypeMethod(linesearch, setup);
242: if (!linesearch->ops->snesfunc) PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunction));
243: linesearch->lambda = linesearch->damping;
244: linesearch->setupcalled = PETSC_TRUE;
245: }
246: PetscFunctionReturn(PETSC_SUCCESS);
247: }
249: /*@
250: SNESLineSearchReset - Undoes the `SNESLineSearchSetUp()` and deletes any `Vec`s or `Mat`s allocated by the line search.
252: Collective
254: Input Parameter:
255: . linesearch - The `SNESLineSearch` instance.
257: Level: developer
259: Note:
260: Usually only called by `SNESReset()`
262: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchSetUp()`
263: @*/
264: PetscErrorCode SNESLineSearchReset(SNESLineSearch linesearch)
265: {
266: PetscFunctionBegin;
267: if (linesearch->ops->reset) PetscUseTypeMethod(linesearch, reset);
269: PetscCall(VecDestroy(&linesearch->vec_sol_new));
270: PetscCall(VecDestroy(&linesearch->vec_func_new));
272: PetscCall(VecDestroyVecs(linesearch->nwork, &linesearch->work));
274: linesearch->nwork = 0;
275: linesearch->setupcalled = PETSC_FALSE;
276: PetscFunctionReturn(PETSC_SUCCESS);
277: }
279: /*@C
280: SNESLineSearchSetFunction - Sets the function evaluation used by the `SNES` line search
281: `
283: Input Parameters:
284: + linesearch - the `SNESLineSearch` context
285: - func - function evaluation routine, this is usually the function provided with `SNESSetFunction()`
287: Calling sequence of `func`:
288: + snes - the `SNES` with which the `SNESLineSearch` context is associated with
289: . x - the input vector
290: - f - the computed value of the function
292: Level: developer
294: Note:
295: By default the `SNESLineSearch` uses the function provided by `SNESSetFunction()` so this is rarely needed
297: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESSetFunction()`
298: @*/
299: PetscErrorCode SNESLineSearchSetFunction(SNESLineSearch linesearch, PetscErrorCode (*func)(SNES snes, Vec x, Vec f))
300: {
301: PetscFunctionBegin;
303: linesearch->ops->snesfunc = func;
304: PetscFunctionReturn(PETSC_SUCCESS);
305: }
307: /*@C
308: SNESLineSearchSetPreCheck - Sets a function that is called after the initial search direction has been computed but
309: before the line search routine has been applied. Allows adjusting the result of (usually a linear solve) that
310: determined the search direction.
312: Logically Collective
314: Input Parameters:
315: + linesearch - the `SNESLineSearch` context
316: . func - [optional] function evaluation routine
317: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
319: Calling sequence of `func`:
320: + ls - the `SNESLineSearch` context
321: . x - the current solution
322: . d - the current seach direction
323: . changed_d - indicates if the search direction has been changed
324: - ctx - the context passed to `SNESLineSearchSetPreCheck()`
326: Level: intermediate
328: Note:
329: Use `SNESLineSearchSetPostCheck()` to change the step after the line search is complete.
331: Use `SNESVISetVariableBounds()` and `SNESVISetComputeVariableBounds()` to cause `SNES` to automatically control the ranges of variables allowed.
333: .seealso: [](ch_snes), `SNES`, `SNESGetLineSearch()`, `SNESLineSearchPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchGetPreCheck()`,
334: `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()`, `SNESSetFunctionDomainError()`, `SNESSetJacobianDomainError()`
336: @*/
337: PetscErrorCode SNESLineSearchSetPreCheck(SNESLineSearch linesearch, PetscErrorCode (*func)(SNESLineSearch ls, Vec x, Vec d, PetscBool *changed_d, void *ctx), void *ctx)
338: {
339: PetscFunctionBegin;
341: if (func) linesearch->ops->precheck = func;
342: if (ctx) linesearch->precheckctx = ctx;
343: PetscFunctionReturn(PETSC_SUCCESS);
344: }
346: /*@C
347: SNESLineSearchGetPreCheck - Gets the pre-check function for the line search routine.
349: Input Parameter:
350: . linesearch - the `SNESLineSearch` context
352: Output Parameters:
353: + func - [optional] function evaluation routine, for calling sequence see `SNESLineSearchSetPreCheck()`
354: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
356: Level: intermediate
358: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchPreCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
359: @*/
360: PetscErrorCode SNESLineSearchGetPreCheck(SNESLineSearch linesearch, PetscErrorCode (**func)(SNESLineSearch, Vec, Vec, PetscBool *, void *), void **ctx)
361: {
362: PetscFunctionBegin;
364: if (func) *func = linesearch->ops->precheck;
365: if (ctx) *ctx = linesearch->precheckctx;
366: PetscFunctionReturn(PETSC_SUCCESS);
367: }
369: /*@C
370: SNESLineSearchSetPostCheck - Sets a user function that is called after the line search has been applied to determine the step
371: direction and length. Allows the user a chance to change or override the decision of the line search routine
373: Logically Collective
375: Input Parameters:
376: + linesearch - the `SNESLineSearch` context
377: . func - [optional] function evaluation routine
378: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
380: Calling sequence of `func`:
381: + ls - the `SNESLineSearch` context
382: . x - the current solution
383: . d - the current seach direction
384: . w - $ w = x + lamba*d $ for some lambda
385: . changed_d - indicates if the search direction `d` has been changed
386: . changed_w - indicates `w` has been changed
387: - ctx - the context passed to `SNESLineSearchSetPreCheck()`
389: Level: intermediate
391: Notes:
392: Use `SNESLineSearchSetPreCheck()` to change the step before the line search is complete.
394: Use `SNESVISetVariableBounds()` and `SNESVISetComputeVariableBounds()` to cause `SNES` to automatically control the ranges of variables allowed.
396: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`, `SNESLineSearchGetPostCheck()`,
397: `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()`, `SNESSetFunctionDomainError()`, `SNESSetJacobianDomainError()`
398: @*/
399: PetscErrorCode SNESLineSearchSetPostCheck(SNESLineSearch linesearch, PetscErrorCode (*func)(SNESLineSearch ls, Vec x, Vec d, Vec w, PetscBool *changed_d, PetscBool *changed_w, void *ctx), void *ctx)
400: {
401: PetscFunctionBegin;
403: if (func) linesearch->ops->postcheck = func;
404: if (ctx) linesearch->postcheckctx = ctx;
405: PetscFunctionReturn(PETSC_SUCCESS);
406: }
408: /*@C
409: SNESLineSearchGetPostCheck - Gets the post-check function for the line search routine.
411: Input Parameter:
412: . linesearch - the `SNESLineSearch` context
414: Output Parameters:
415: + func - [optional] function evaluation routine, see for the calling sequence `SNESLineSearchSetPostCheck()`
416: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
418: Level: intermediate
420: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchGetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchPostCheck()`, `SNESLineSearchSetPreCheck()`
421: @*/
422: PetscErrorCode SNESLineSearchGetPostCheck(SNESLineSearch linesearch, PetscErrorCode (**func)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *), void **ctx)
423: {
424: PetscFunctionBegin;
426: if (func) *func = linesearch->ops->postcheck;
427: if (ctx) *ctx = linesearch->postcheckctx;
428: PetscFunctionReturn(PETSC_SUCCESS);
429: }
431: /*@
432: SNESLineSearchPreCheck - Prepares the line search for being applied.
434: Logically Collective
436: Input Parameters:
437: + linesearch - The linesearch instance.
438: . X - The current solution
439: - Y - The step direction
441: Output Parameter:
442: . changed - Indicator that the precheck routine has changed `Y`
444: Level: advanced
446: Note:
447: This calls any function provided with `SNESLineSearchSetPreCheck()` and is called automatically inside the line search routines
449: Developer Note:
450: The use of `PetscObjectGetState()` would eliminate the need for the `changed` argument to be provided
452: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`, `SNESLineSearchSetPostCheck()`,
453: `SNESLineSearchGetPostCheck()`
454: @*/
455: PetscErrorCode SNESLineSearchPreCheck(SNESLineSearch linesearch, Vec X, Vec Y, PetscBool *changed)
456: {
457: PetscFunctionBegin;
458: *changed = PETSC_FALSE;
459: if (linesearch->ops->precheck) {
460: PetscUseTypeMethod(linesearch, precheck, X, Y, changed, linesearch->precheckctx);
462: }
463: PetscFunctionReturn(PETSC_SUCCESS);
464: }
466: /*@
467: SNESLineSearchPostCheck - Hook to modify step direction or updated solution after a successful linesearch
469: Logically Collective
471: Input Parameters:
472: + linesearch - The line search context
473: . X - The last solution
474: . Y - The step direction
475: - W - The updated solution, $ W = X + lambda*Y $ for some lambda
477: Output Parameters:
478: + changed_Y - Indicator if the direction `Y` has been changed.
479: - changed_W - Indicator if the new candidate solution `W` has been changed.
481: Level: developer
483: Note:
484: This calls any function provided with `SNESLineSearchSetPostCheck()` and is called automatically inside the line search routines
486: Developer Note:
487: The use of `PetscObjectGetState()` would eliminate the need for the `changed_Y` and `changed_W` arguments to be provided
489: .seealso: [](ch_snes), `SNES`, `SNESGetLineSearch()`, `SNESLineSearchPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPrecheck()`, `SNESLineSearchGetPrecheck()`
490: @*/
491: PetscErrorCode SNESLineSearchPostCheck(SNESLineSearch linesearch, Vec X, Vec Y, Vec W, PetscBool *changed_Y, PetscBool *changed_W)
492: {
493: PetscFunctionBegin;
494: *changed_Y = PETSC_FALSE;
495: *changed_W = PETSC_FALSE;
496: if (linesearch->ops->postcheck) {
497: PetscUseTypeMethod(linesearch, postcheck, X, Y, W, changed_Y, changed_W, linesearch->postcheckctx);
500: }
501: PetscFunctionReturn(PETSC_SUCCESS);
502: }
504: /*@C
505: SNESLineSearchPreCheckPicard - Implements a correction that is sometimes useful to improve the convergence rate of Picard iteration
507: Logically Collective
509: Input Parameters:
510: + linesearch - the line search context
511: . X - base state for this step
512: - ctx - context for this function
514: Input/Output Parameter:
515: . Y - correction, possibly modified
517: Output Parameter:
518: . changed - flag indicating that `Y` was modified
520: Options Database Keys:
521: + -snes_linesearch_precheck_picard - activate this routine
522: - -snes_linesearch_precheck_picard_angle - angle
524: Level: advanced
526: Notes:
527: This function should be passed to `SNESLineSearchSetPreCheck()`
529: The justification for this method involves the linear convergence of a Picard iteration
530: so the Picard linearization should be provided in place of the "Jacobian". This correction
531: is generally not useful when using a Newton linearization.
533: References:
534: . - * - Hindmarsh and Payne (1996) Time step limits for stable solutions of the ice sheet equation, Annals of Glaciology.
536: Developer Note:
537: The use of `PetscObjectGetState()` would eliminate the need for the `changed` argument to be provided
539: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESSetPicard()`, `SNESGetLineSearch()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
540: @*/
541: PetscErrorCode SNESLineSearchPreCheckPicard(SNESLineSearch linesearch, Vec X, Vec Y, PetscBool *changed, void *ctx)
542: {
543: PetscReal angle = *(PetscReal *)linesearch->precheckctx;
544: Vec Ylast;
545: PetscScalar dot;
546: PetscInt iter;
547: PetscReal ynorm, ylastnorm, theta, angle_radians;
548: SNES snes;
550: PetscFunctionBegin;
551: PetscCall(SNESLineSearchGetSNES(linesearch, &snes));
552: PetscCall(PetscObjectQuery((PetscObject)snes, "SNESLineSearchPreCheckPicard_Ylast", (PetscObject *)&Ylast));
553: if (!Ylast) {
554: PetscCall(VecDuplicate(Y, &Ylast));
555: PetscCall(PetscObjectCompose((PetscObject)snes, "SNESLineSearchPreCheckPicard_Ylast", (PetscObject)Ylast));
556: PetscCall(PetscObjectDereference((PetscObject)Ylast));
557: }
558: PetscCall(SNESGetIterationNumber(snes, &iter));
559: if (iter < 2) {
560: PetscCall(VecCopy(Y, Ylast));
561: *changed = PETSC_FALSE;
562: PetscFunctionReturn(PETSC_SUCCESS);
563: }
565: PetscCall(VecDot(Y, Ylast, &dot));
566: PetscCall(VecNorm(Y, NORM_2, &ynorm));
567: PetscCall(VecNorm(Ylast, NORM_2, &ylastnorm));
568: /* Compute the angle between the vectors Y and Ylast, clip to keep inside the domain of acos() */
569: theta = PetscAcosReal((PetscReal)PetscClipInterval(PetscAbsScalar(dot) / (ynorm * ylastnorm), -1.0, 1.0));
570: angle_radians = angle * PETSC_PI / 180.;
571: if (PetscAbsReal(theta) < angle_radians || PetscAbsReal(theta - PETSC_PI) < angle_radians) {
572: /* Modify the step Y */
573: PetscReal alpha, ydiffnorm;
574: PetscCall(VecAXPY(Ylast, -1.0, Y));
575: PetscCall(VecNorm(Ylast, NORM_2, &ydiffnorm));
576: alpha = (ydiffnorm > .001 * ylastnorm) ? ylastnorm / ydiffnorm : 1000.0;
577: PetscCall(VecCopy(Y, Ylast));
578: PetscCall(VecScale(Y, alpha));
579: 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));
580: *changed = PETSC_TRUE;
581: } else {
582: PetscCall(PetscInfo(snes, "Angle %14.12e degrees exceeds threshold %14.12e, no correction applied\n", (double)(theta * 180. / PETSC_PI), (double)angle));
583: PetscCall(VecCopy(Y, Ylast));
584: *changed = PETSC_FALSE;
585: }
586: PetscFunctionReturn(PETSC_SUCCESS);
587: }
589: /*@
590: SNESLineSearchApply - Computes the line-search update.
592: Collective
594: Input Parameters:
595: + linesearch - The line search context
596: - Y - The search direction
598: Input/Output Parameters:
599: + X - The current solution, on output the new solution
600: . F - The current function value, on output the new function value at the solution value `X`
601: - fnorm - The current norm of `F`, on output the new norm of `F`
603: Options Database Keys:
604: + -snes_linesearch_type - basic (or equivalently none), bt, l2, cp, nleqerr, shell
605: . -snes_linesearch_monitor [:filename] - Print progress of line searches
606: . -snes_linesearch_damping - The linesearch damping parameter, default is 1.0 (no damping)
607: . -snes_linesearch_norms - Turn on/off the linesearch norms computation (SNESLineSearchSetComputeNorms())
608: . -snes_linesearch_keeplambda - Keep the previous search length as the initial guess
609: - -snes_linesearch_max_it - The number of iterations for iterative line searches
611: Level: intermediate
613: Notes:
614: This is typically called from within a `SNESSolve()` implementation in order to
615: help with convergence of the nonlinear method. Various `SNES` types use line searches
616: in different ways, but the overarching theme is that a line search is used to determine
617: an optimal damping parameter of a step at each iteration of the method. Each
618: application of the line search may invoke `SNESComputeFunction()` several times, and
619: therefore may be fairly expensive.
621: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchPreCheck()`, `SNESLineSearchPostCheck()`, `SNESSolve()`, `SNESComputeFunction()`, `SNESLineSearchSetComputeNorms()`,
622: `SNESLineSearchType`, `SNESLineSearchSetType()`
623: @*/
624: PetscErrorCode SNESLineSearchApply(SNESLineSearch linesearch, Vec X, Vec F, PetscReal *fnorm, Vec Y)
625: {
626: PetscFunctionBegin;
632: linesearch->result = SNES_LINESEARCH_SUCCEEDED;
634: linesearch->vec_sol = X;
635: linesearch->vec_update = Y;
636: linesearch->vec_func = F;
638: PetscCall(SNESLineSearchSetUp(linesearch));
640: if (!linesearch->keeplambda) linesearch->lambda = linesearch->damping; /* set the initial guess to lambda */
642: if (fnorm) linesearch->fnorm = *fnorm;
643: else PetscCall(VecNorm(F, NORM_2, &linesearch->fnorm));
645: PetscCall(PetscLogEventBegin(SNESLINESEARCH_Apply, linesearch, X, F, Y));
647: PetscUseTypeMethod(linesearch, apply);
649: PetscCall(PetscLogEventEnd(SNESLINESEARCH_Apply, linesearch, X, F, Y));
651: if (fnorm) *fnorm = linesearch->fnorm;
652: PetscFunctionReturn(PETSC_SUCCESS);
653: }
655: /*@
656: SNESLineSearchDestroy - Destroys the line search instance.
658: Collective
660: Input Parameter:
661: . linesearch - The line search context
663: Level: developer
665: Note:
666: The line search in `SNES` is automatically called on `SNESDestroy()` so this call is rarely needed
668: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchReset()`, `SNESDestroy()`
669: @*/
670: PetscErrorCode SNESLineSearchDestroy(SNESLineSearch *linesearch)
671: {
672: PetscFunctionBegin;
673: if (!*linesearch) PetscFunctionReturn(PETSC_SUCCESS);
675: if (--((PetscObject)(*linesearch))->refct > 0) {
676: *linesearch = NULL;
677: PetscFunctionReturn(PETSC_SUCCESS);
678: }
679: PetscCall(PetscObjectSAWsViewOff((PetscObject)*linesearch));
680: PetscCall(SNESLineSearchReset(*linesearch));
681: PetscTryTypeMethod(*linesearch, destroy);
682: PetscCall(PetscViewerDestroy(&(*linesearch)->monitor));
683: PetscCall(SNESLineSearchMonitorCancel((*linesearch)));
684: PetscCall(PetscHeaderDestroy(linesearch));
685: PetscFunctionReturn(PETSC_SUCCESS);
686: }
688: /*@
689: SNESLineSearchSetDefaultMonitor - Turns on/off printing useful information and debugging output about the line search.
691: Logically Collective
693: Input Parameters:
694: + linesearch - the linesearch object
695: - viewer - an `PETSCVIEWERASCII` `PetscViewer` or `NULL` to turn off monitor
697: Options Database Key:
698: . -snes_linesearch_monitor [:filename] - enables the monitor
700: Level: intermediate
702: Developer Notes:
703: This monitor is implemented differently than the other line search monitors that are set with
704: `SNESLineSearchMonitorSet()` since it is called in many locations of the line search routines to display aspects of the
705: line search that are not visible to the other monitors.
707: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `PETSCVIEWERASCII`, `SNESGetLineSearch()`, `SNESLineSearchGetDefaultMonitor()`, `PetscViewer`, `SNESLineSearchSetMonitor()`,
708: `SNESLineSearchMonitorSetFromOptions()`
709: @*/
710: PetscErrorCode SNESLineSearchSetDefaultMonitor(SNESLineSearch linesearch, PetscViewer viewer)
711: {
712: PetscFunctionBegin;
713: if (viewer) PetscCall(PetscObjectReference((PetscObject)viewer));
714: PetscCall(PetscViewerDestroy(&linesearch->monitor));
715: linesearch->monitor = viewer;
716: PetscFunctionReturn(PETSC_SUCCESS);
717: }
719: /*@
720: SNESLineSearchGetDefaultMonitor - Gets the `PetscViewer` instance for the default line search monitor that is turned on with `SNESLineSearchSetDefaultMonitor()`
722: Logically Collective
724: Input Parameter:
725: . linesearch - the line search context
727: Output Parameter:
728: . monitor - monitor context
730: Level: intermediate
732: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`, `SNESLineSearchSetDefaultMonitor()`, `PetscViewer`
733: @*/
734: PetscErrorCode SNESLineSearchGetDefaultMonitor(SNESLineSearch linesearch, PetscViewer *monitor)
735: {
736: PetscFunctionBegin;
738: *monitor = linesearch->monitor;
739: PetscFunctionReturn(PETSC_SUCCESS);
740: }
742: /*@C
743: SNESLineSearchMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated in the options database
745: Collective
747: Input Parameters:
748: + ls - `SNESLineSearch` object to monitor
749: . name - the monitor type
750: . help - message indicating what monitoring is done
751: . manual - manual page for the monitor
752: . monitor - the monitor function
753: - monitorsetup - a function that is called once ONLY if the user selected this monitor that may set additional features of the `SNESLineSearch` or `PetscViewer`
755: Calling sequence of `monitor`:
756: + ls - `SNESLineSearch` object being monitored
757: - vf - a `PetscViewerAndFormat` struct that provides the `PetscViewer` and `PetscViewerFormat` being used
759: Calling sequence of `monitorsetup`:
760: + ls - `SNESLineSearch` object being monitored
761: - vf - a `PetscViewerAndFormat` struct that provides the `PetscViewer` and `PetscViewerFormat` being used
763: Level: advanced
765: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetMonitor()`, `PetscOptionsGetViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
766: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`
767: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
768: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
769: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
770: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
771: `PetscOptionsFList()`, `PetscOptionsEList()`
772: @*/
773: 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))
774: {
775: PetscViewer viewer;
776: PetscViewerFormat format;
777: PetscBool flg;
779: PetscFunctionBegin;
780: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)ls), ((PetscObject)ls)->options, ((PetscObject)ls)->prefix, name, &viewer, &format, &flg));
781: if (flg) {
782: PetscViewerAndFormat *vf;
783: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
784: PetscCall(PetscObjectDereference((PetscObject)viewer));
785: if (monitorsetup) PetscCall((*monitorsetup)(ls, vf));
786: PetscCall(SNESLineSearchMonitorSet(ls, (PetscErrorCode(*)(SNESLineSearch, void *))monitor, vf, (PetscErrorCode(*)(void **))PetscViewerAndFormatDestroy));
787: }
788: PetscFunctionReturn(PETSC_SUCCESS);
789: }
791: /*@
792: SNESLineSearchSetFromOptions - Sets options for the line search
794: Logically Collective
796: Input Parameter:
797: . linesearch - a `SNESLineSearch` line search context
799: Options Database Keys:
800: + -snes_linesearch_type <type> - basic (or equivalently none), bt, l2, cp, nleqerr, shell
801: . -snes_linesearch_order <order> - 1, 2, 3. Most types only support certain orders (bt supports 2 or 3)
802: . -snes_linesearch_norms - Turn on/off the linesearch norms for the basic linesearch typem (`SNESLineSearchSetComputeNorms()`)
803: . -snes_linesearch_minlambda - The minimum step length
804: . -snes_linesearch_maxstep - The maximum step size
805: . -snes_linesearch_rtol - Relative tolerance for iterative line searches
806: . -snes_linesearch_atol - Absolute tolerance for iterative line searches
807: . -snes_linesearch_ltol - Change in lambda tolerance for iterative line searches
808: . -snes_linesearch_max_it - The number of iterations for iterative line searches
809: . -snes_linesearch_monitor [:filename] - Print progress of line searches
810: . -snes_linesearch_monitor_solution_update [viewer:filename:format] - view each update tried by line search routine
811: . -snes_linesearch_damping - The linesearch damping parameter
812: . -snes_linesearch_keeplambda - Keep the previous search length as the initial guess.
813: . -snes_linesearch_precheck_picard - Use precheck that speeds up convergence of picard method
814: - -snes_linesearch_precheck_picard_angle - Angle used in Picard precheck method
816: Level: intermediate
818: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchCreate()`, `SNESLineSearchSetOrder()`, `SNESLineSearchSetType()`, `SNESLineSearchSetTolerances()`, `SNESLineSearchSetDamping()`, `SNESLineSearchPreCheckPicard()`,
819: `SNESLineSearchType`, `SNESLineSearchSetComputeNorms()`
820: @*/
821: PetscErrorCode SNESLineSearchSetFromOptions(SNESLineSearch linesearch)
822: {
823: const char *deft = SNESLINESEARCHBASIC;
824: char type[256];
825: PetscBool flg, set;
826: PetscViewer viewer;
828: PetscFunctionBegin;
829: PetscCall(SNESLineSearchRegisterAll());
831: PetscObjectOptionsBegin((PetscObject)linesearch);
832: if (((PetscObject)linesearch)->type_name) deft = ((PetscObject)linesearch)->type_name;
833: PetscCall(PetscOptionsFList("-snes_linesearch_type", "Linesearch type", "SNESLineSearchSetType", SNESLineSearchList, deft, type, 256, &flg));
834: if (flg) {
835: PetscCall(SNESLineSearchSetType(linesearch, type));
836: } else if (!((PetscObject)linesearch)->type_name) {
837: PetscCall(SNESLineSearchSetType(linesearch, deft));
838: }
840: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)linesearch), ((PetscObject)linesearch)->options, ((PetscObject)linesearch)->prefix, "-snes_linesearch_monitor", &viewer, NULL, &set));
841: if (set) {
842: PetscCall(SNESLineSearchSetDefaultMonitor(linesearch, viewer));
843: PetscCall(PetscViewerDestroy(&viewer));
844: }
845: PetscCall(SNESLineSearchMonitorSetFromOptions(linesearch, "-snes_linesearch_monitor_solution_update", "View correction at each iteration", "SNESLineSearchMonitorSolutionUpdate", SNESLineSearchMonitorSolutionUpdate, NULL));
847: /* tolerances */
848: PetscCall(PetscOptionsReal("-snes_linesearch_minlambda", "Minimum step length", "SNESLineSearchSetTolerances", linesearch->steptol, &linesearch->steptol, NULL));
849: PetscCall(PetscOptionsReal("-snes_linesearch_maxstep", "Maximum step size", "SNESLineSearchSetTolerances", linesearch->maxstep, &linesearch->maxstep, NULL));
850: PetscCall(PetscOptionsReal("-snes_linesearch_rtol", "Relative tolerance for iterative line search", "SNESLineSearchSetTolerances", linesearch->rtol, &linesearch->rtol, NULL));
851: PetscCall(PetscOptionsReal("-snes_linesearch_atol", "Absolute tolerance for iterative line search", "SNESLineSearchSetTolerances", linesearch->atol, &linesearch->atol, NULL));
852: PetscCall(PetscOptionsReal("-snes_linesearch_ltol", "Change in lambda tolerance for iterative line search", "SNESLineSearchSetTolerances", linesearch->ltol, &linesearch->ltol, NULL));
853: PetscCall(PetscOptionsInt("-snes_linesearch_max_it", "Maximum iterations for iterative line searches", "SNESLineSearchSetTolerances", linesearch->max_its, &linesearch->max_its, NULL));
855: /* damping parameters */
856: PetscCall(PetscOptionsReal("-snes_linesearch_damping", "Line search damping and initial step guess", "SNESLineSearchSetDamping", linesearch->damping, &linesearch->damping, NULL));
858: PetscCall(PetscOptionsBool("-snes_linesearch_keeplambda", "Use previous lambda as damping", "SNESLineSearchSetKeepLambda", linesearch->keeplambda, &linesearch->keeplambda, NULL));
860: /* precheck */
861: PetscCall(PetscOptionsBool("-snes_linesearch_precheck_picard", "Use a correction that sometimes improves convergence of Picard iteration", "SNESLineSearchPreCheckPicard", flg, &flg, &set));
862: if (set) {
863: if (flg) {
864: linesearch->precheck_picard_angle = 10.; /* correction only active if angle is less than 10 degrees */
866: 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));
867: PetscCall(SNESLineSearchSetPreCheck(linesearch, SNESLineSearchPreCheckPicard, &linesearch->precheck_picard_angle));
868: } else {
869: PetscCall(SNESLineSearchSetPreCheck(linesearch, NULL, NULL));
870: }
871: }
872: PetscCall(PetscOptionsInt("-snes_linesearch_order", "Order of approximation used in the line search", "SNESLineSearchSetOrder", linesearch->order, &linesearch->order, NULL));
873: PetscCall(PetscOptionsBool("-snes_linesearch_norms", "Compute final norms in line search", "SNESLineSearchSetComputeNorms", linesearch->norms, &linesearch->norms, NULL));
875: PetscTryTypeMethod(linesearch, setfromoptions, PetscOptionsObject);
877: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)linesearch, PetscOptionsObject));
878: PetscOptionsEnd();
879: PetscFunctionReturn(PETSC_SUCCESS);
880: }
882: /*@
883: SNESLineSearchView - Prints useful information about the line search
885: Logically Collective
887: Input Parameters:
888: + linesearch - line search context
889: - viewer - the `PetscViewer` to display the line search information to
891: Level: intermediate
893: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `PetscViewer`, `SNESLineSearchCreate()`
894: @*/
895: PetscErrorCode SNESLineSearchView(SNESLineSearch linesearch, PetscViewer viewer)
896: {
897: PetscBool iascii;
899: PetscFunctionBegin;
901: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)linesearch), &viewer));
903: PetscCheckSameComm(linesearch, 1, viewer, 2);
905: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
906: if (iascii) {
907: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)linesearch, viewer));
908: PetscCall(PetscViewerASCIIPushTab(viewer));
909: PetscTryTypeMethod(linesearch, view, viewer);
910: PetscCall(PetscViewerASCIIPopTab(viewer));
911: PetscCall(PetscViewerASCIIPrintf(viewer, " maxstep=%e, minlambda=%e\n", (double)linesearch->maxstep, (double)linesearch->steptol));
912: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%e, absolute=%e, lambda=%e\n", (double)linesearch->rtol, (double)linesearch->atol, (double)linesearch->ltol));
913: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT "\n", linesearch->max_its));
914: if (linesearch->ops->precheck) {
915: if (linesearch->ops->precheck == SNESLineSearchPreCheckPicard) {
916: PetscCall(PetscViewerASCIIPrintf(viewer, " using precheck step to speed up Picard convergence\n"));
917: } else {
918: PetscCall(PetscViewerASCIIPrintf(viewer, " using user-defined precheck step\n"));
919: }
920: }
921: if (linesearch->ops->postcheck) PetscCall(PetscViewerASCIIPrintf(viewer, " using user-defined postcheck step\n"));
922: }
923: PetscFunctionReturn(PETSC_SUCCESS);
924: }
926: /*@C
927: SNESLineSearchGetType - Gets the `SNESLinesearchType` of a `SNESLineSearch`
929: Logically Collective
931: Input Parameter:
932: . linesearch - the line search context
934: Output Parameter:
935: . type - The type of line search, or `NULL` if not set
937: Level: intermediate
939: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`, `SNESLineSearchSetType()`
940: @*/
941: PetscErrorCode SNESLineSearchGetType(SNESLineSearch linesearch, SNESLineSearchType *type)
942: {
943: PetscFunctionBegin;
945: PetscAssertPointer(type, 2);
946: *type = ((PetscObject)linesearch)->type_name;
947: PetscFunctionReturn(PETSC_SUCCESS);
948: }
950: /*@C
951: SNESLineSearchSetType - Sets the `SNESLinesearchType` of a `SNESLineSearch`
953: Logically Collective
955: Input Parameters:
956: + linesearch - the line search context
957: - type - The type of line search to be used, see `SNESLineSearchType`
959: Options Database Key:
960: . -snes_linesearch_type <type> - basic (or equivalently none), bt, l2, cp, nleqerr, shell
962: Level: intermediate
964: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchType`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`, `SNESLineSearchGetType()`
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: if (linesearch->ops->destroy) {
982: PetscCall((*(linesearch)->ops->destroy)(linesearch));
983: linesearch->ops->destroy = NULL;
984: }
985: /* Reinitialize function pointers in SNESLineSearchOps structure */
986: linesearch->ops->apply = NULL;
987: linesearch->ops->view = NULL;
988: linesearch->ops->setfromoptions = NULL;
989: linesearch->ops->destroy = NULL;
991: PetscCall(PetscObjectChangeTypeName((PetscObject)linesearch, type));
992: PetscCall((*r)(linesearch));
993: PetscFunctionReturn(PETSC_SUCCESS);
994: }
996: /*@
997: SNESLineSearchSetSNES - Sets the `SNES` for the linesearch for function evaluation.
999: Input Parameters:
1000: + linesearch - the line search context
1001: - snes - The `SNES` instance
1003: Level: developer
1005: Note:
1006: This happens automatically when the line search is obtained/created with
1007: `SNESGetLineSearch()`. This routine is therefore mainly called within `SNES`
1008: implementations.
1010: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetSNES()`, `SNESLineSearchSetVecs()`
1011: @*/
1012: PetscErrorCode SNESLineSearchSetSNES(SNESLineSearch linesearch, SNES snes)
1013: {
1014: PetscFunctionBegin;
1017: linesearch->snes = snes;
1018: PetscFunctionReturn(PETSC_SUCCESS);
1019: }
1021: /*@
1022: SNESLineSearchGetSNES - Gets the `SNES` instance associated with the line search.
1024: Not Collective
1026: Input Parameter:
1027: . linesearch - the line search context
1029: Output Parameter:
1030: . snes - The `SNES` instance
1032: Level: developer
1034: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESType`, `SNESLineSearchSetVecs()`
1035: @*/
1036: PetscErrorCode SNESLineSearchGetSNES(SNESLineSearch linesearch, SNES *snes)
1037: {
1038: PetscFunctionBegin;
1040: PetscAssertPointer(snes, 2);
1041: *snes = linesearch->snes;
1042: PetscFunctionReturn(PETSC_SUCCESS);
1043: }
1045: /*@
1046: SNESLineSearchGetLambda - Gets the last line search steplength used
1048: Not Collective
1050: Input Parameter:
1051: . linesearch - the line search context
1053: Output Parameter:
1054: . lambda - The last steplength computed during `SNESLineSearchApply()`
1056: Level: advanced
1058: Note:
1059: This is useful in methods where the solver is ill-scaled and
1060: requires some adaptive notion of the difference in scale between the
1061: solution and the function. For instance, `SNESQN` may be scaled by the
1062: line search lambda using the argument -snes_qn_scaling ls.
1064: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetLambda()`, `SNESLineSearchGetDamping()`, `SNESLineSearchApply()`
1065: @*/
1066: PetscErrorCode SNESLineSearchGetLambda(SNESLineSearch linesearch, PetscReal *lambda)
1067: {
1068: PetscFunctionBegin;
1070: PetscAssertPointer(lambda, 2);
1071: *lambda = linesearch->lambda;
1072: PetscFunctionReturn(PETSC_SUCCESS);
1073: }
1075: /*@
1076: SNESLineSearchSetLambda - Sets the line search steplength
1078: Input Parameters:
1079: + linesearch - line search context
1080: - lambda - The steplength to use
1082: Level: advanced
1084: Note:
1085: This routine is typically used within implementations of `SNESLineSearchApply()`
1086: to set the final steplength. This routine (and `SNESLineSearchGetLambda()`) were
1087: added in order to facilitate Quasi-Newton methods that use the previous steplength
1088: as an inner scaling parameter.
1090: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetLambda()`
1091: @*/
1092: PetscErrorCode SNESLineSearchSetLambda(SNESLineSearch linesearch, PetscReal lambda)
1093: {
1094: PetscFunctionBegin;
1096: linesearch->lambda = lambda;
1097: PetscFunctionReturn(PETSC_SUCCESS);
1098: }
1100: /*@
1101: SNESLineSearchGetTolerances - Gets the tolerances for the line search.
1103: Not Collective
1105: Input Parameter:
1106: . linesearch - the line search context
1108: Output Parameters:
1109: + steptol - The minimum steplength
1110: . maxstep - The maximum steplength
1111: . rtol - The relative tolerance for iterative line searches
1112: . atol - The absolute tolerance for iterative line searches
1113: . ltol - The change in lambda tolerance for iterative line searches
1114: - max_its - The maximum number of iterations of the line search
1116: Level: intermediate
1118: Note:
1119: Different line searches may implement these parameters slightly differently as
1120: the type requires.
1122: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetTolerances()`
1123: @*/
1124: PetscErrorCode SNESLineSearchGetTolerances(SNESLineSearch linesearch, PetscReal *steptol, PetscReal *maxstep, PetscReal *rtol, PetscReal *atol, PetscReal *ltol, PetscInt *max_its)
1125: {
1126: PetscFunctionBegin;
1128: if (steptol) {
1129: PetscAssertPointer(steptol, 2);
1130: *steptol = linesearch->steptol;
1131: }
1132: if (maxstep) {
1133: PetscAssertPointer(maxstep, 3);
1134: *maxstep = linesearch->maxstep;
1135: }
1136: if (rtol) {
1137: PetscAssertPointer(rtol, 4);
1138: *rtol = linesearch->rtol;
1139: }
1140: if (atol) {
1141: PetscAssertPointer(atol, 5);
1142: *atol = linesearch->atol;
1143: }
1144: if (ltol) {
1145: PetscAssertPointer(ltol, 6);
1146: *ltol = linesearch->ltol;
1147: }
1148: if (max_its) {
1149: PetscAssertPointer(max_its, 7);
1150: *max_its = linesearch->max_its;
1151: }
1152: PetscFunctionReturn(PETSC_SUCCESS);
1153: }
1155: /*@
1156: SNESLineSearchSetTolerances - Sets the tolerances for the linesearch.
1158: Collective
1160: Input Parameters:
1161: + linesearch - the line search context
1162: . steptol - The minimum steplength
1163: . maxstep - The maximum steplength
1164: . rtol - The relative tolerance for iterative line searches
1165: . atol - The absolute tolerance for iterative line searches
1166: . ltol - The change in lambda tolerance for iterative line searches
1167: - max_it - The maximum number of iterations of the line search
1169: Options Database Keys:
1170: + -snes_linesearch_minlambda - The minimum step length
1171: . -snes_linesearch_maxstep - The maximum step size
1172: . -snes_linesearch_rtol - Relative tolerance for iterative line searches
1173: . -snes_linesearch_atol - Absolute tolerance for iterative line searches
1174: . -snes_linesearch_ltol - Change in lambda tolerance for iterative line searches
1175: - -snes_linesearch_max_it - The number of iterations for iterative line searches
1177: Level: intermediate
1179: Note:
1180: The user may choose to not set any of the tolerances using `PETSC_DEFAULT` in place of an argument.
1182: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetTolerances()`
1183: @*/
1184: PetscErrorCode SNESLineSearchSetTolerances(SNESLineSearch linesearch, PetscReal steptol, PetscReal maxstep, PetscReal rtol, PetscReal atol, PetscReal ltol, PetscInt max_it)
1185: {
1186: PetscFunctionBegin;
1195: if (steptol != (PetscReal)PETSC_DEFAULT) {
1196: PetscCheck(steptol >= 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Minimum step length %14.12e must be non-negative", (double)steptol);
1197: linesearch->steptol = steptol;
1198: }
1200: if (maxstep != (PetscReal)PETSC_DEFAULT) {
1201: PetscCheck(maxstep >= 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Maximum step length %14.12e must be non-negative", (double)maxstep);
1202: linesearch->maxstep = maxstep;
1203: }
1205: if (rtol != (PetscReal)PETSC_DEFAULT) {
1206: 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);
1207: linesearch->rtol = rtol;
1208: }
1210: if (atol != (PetscReal)PETSC_DEFAULT) {
1211: PetscCheck(atol >= 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %14.12e must be non-negative", (double)atol);
1212: linesearch->atol = atol;
1213: }
1215: if (ltol != (PetscReal)PETSC_DEFAULT) {
1216: PetscCheck(ltol >= 0.0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Lambda tolerance %14.12e must be non-negative", (double)ltol);
1217: linesearch->ltol = ltol;
1218: }
1220: if (max_it != PETSC_DEFAULT) {
1221: PetscCheck(max_it >= 0, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", max_it);
1222: linesearch->max_its = max_it;
1223: }
1224: PetscFunctionReturn(PETSC_SUCCESS);
1225: }
1227: /*@
1228: SNESLineSearchGetDamping - Gets the line search damping parameter.
1230: Input Parameter:
1231: . linesearch - the line search context
1233: Output Parameter:
1234: . damping - The damping parameter
1236: Level: advanced
1238: .seealso: [](ch_snes), `SNES`, `SNESLineSearchGetStepTolerance()`, `SNESQN`
1239: @*/
1240: PetscErrorCode SNESLineSearchGetDamping(SNESLineSearch linesearch, PetscReal *damping)
1241: {
1242: PetscFunctionBegin;
1244: PetscAssertPointer(damping, 2);
1245: *damping = linesearch->damping;
1246: PetscFunctionReturn(PETSC_SUCCESS);
1247: }
1249: /*@
1250: SNESLineSearchSetDamping - Sets the line search damping parameter.
1252: Input Parameters:
1253: + linesearch - the line search context
1254: - damping - The damping parameter
1256: Options Database Key:
1257: . -snes_linesearch_damping <damping> - the damping value
1259: Level: intermediate
1261: Note:
1262: The `SNESLINESEARCHNONE` line search merely takes the update step scaled by the damping parameter.
1263: The use of the damping parameter in the `SNESLINESEARCHL2` and `SNESLINESEARCHCP` line searches is much more subtle;
1264: it is used as a starting point in calculating the secant step. However, the eventual
1265: step may be of greater length than the damping parameter. In the `SNESLINESEARCHBT` line search it is
1266: used as the maximum possible step length, as the `SNESLINESEARCHBT` line search only backtracks.
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
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 - Gets 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
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: /*@C
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: /*@C
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: Fortran Notes:
1596: The user should pass in a string 'prefix' of
1597: sufficient length to hold the prefix.
1599: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESAppendOptionsPrefix()`
1600: @*/
1601: PetscErrorCode SNESLineSearchGetOptionsPrefix(SNESLineSearch linesearch, const char *prefix[])
1602: {
1603: PetscFunctionBegin;
1605: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)linesearch, prefix));
1606: PetscFunctionReturn(PETSC_SUCCESS);
1607: }
1609: /*@C
1610: SNESLineSearchSetWorkVecs - Sets work vectors for the line search.
1612: Input Parameters:
1613: + linesearch - the `SNESLineSearch` context
1614: - nwork - the number of work vectors
1616: Level: developer
1618: Developer Note:
1619: This is called from within the set up routines for each of the line search types `SNESLineSearchType`
1621: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESSetWorkVecs()`
1622: @*/
1623: PetscErrorCode SNESLineSearchSetWorkVecs(SNESLineSearch linesearch, PetscInt nwork)
1624: {
1625: PetscFunctionBegin;
1626: PetscCheck(linesearch->vec_sol, PetscObjectComm((PetscObject)linesearch), PETSC_ERR_USER, "Cannot get linesearch work-vectors without setting a solution vec!");
1627: PetscCall(VecDuplicateVecs(linesearch->vec_sol, nwork, &linesearch->work));
1628: PetscFunctionReturn(PETSC_SUCCESS);
1629: }
1631: /*@
1632: SNESLineSearchGetReason - Gets the success/failure status of the last line search application
1634: Input Parameter:
1635: . linesearch - the line search context
1637: Output Parameter:
1638: . result - The success or failure status
1640: Level: developer
1642: Note:
1643: This is typically called after `SNESLineSearchApply()` in order to determine if the line search failed
1644: (and set into the `SNES` convergence accordingly).
1646: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetReason()`, `SNESLineSearchReason`
1647: @*/
1648: PetscErrorCode SNESLineSearchGetReason(SNESLineSearch linesearch, SNESLineSearchReason *result)
1649: {
1650: PetscFunctionBegin;
1652: PetscAssertPointer(result, 2);
1653: *result = linesearch->result;
1654: PetscFunctionReturn(PETSC_SUCCESS);
1655: }
1657: /*@
1658: SNESLineSearchSetReason - Sets the success/failure status of the line search application
1660: Input Parameters:
1661: + linesearch - the line search context
1662: - result - The success or failure status
1664: Level: developer
1666: Note:
1667: This is typically called in a `SNESLineSearchType` implementation of `SNESLineSearchApply()` or a `SNESLINESEARCHSHELL` implementation to set
1668: the success or failure of the line search method.
1670: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchReason`, `SNESLineSearchGetSResult()`
1671: @*/
1672: PetscErrorCode SNESLineSearchSetReason(SNESLineSearch linesearch, SNESLineSearchReason result)
1673: {
1674: PetscFunctionBegin;
1676: linesearch->result = result;
1677: PetscFunctionReturn(PETSC_SUCCESS);
1678: }
1680: // PetscClangLinter pragma disable: -fdoc-param-list-func-parameter-documentation
1681: /*@C
1682: SNESLineSearchSetVIFunctions - Sets VI-specific functions for line search computation.
1684: Logically Collective
1686: Input Parameters:
1687: + linesearch - the linesearch object
1688: . projectfunc - function for projecting the function to the bounds, see `SNESLineSearchSetVIFunctions` for calling sequence
1689: - normfunc - function for computing the norm of an active set, see `SNESLineSearchSetVIFunctions ` for calling sequence
1691: Level: advanced
1693: Notes:
1694: The VI solvers require projection of the solution to the feasible set. `projectfunc` should implement this.
1696: The VI solvers require special evaluation of the function norm such that the norm is only calculated
1697: on the inactive set. This should be implemented by `normfunc`.
1699: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchGetVIFunctions()`, `SNESLineSearchSetPostCheck()`, `SNESLineSearchSetPreCheck()`
1700: @*/
1701: PetscErrorCode SNESLineSearchSetVIFunctions(SNESLineSearch linesearch, SNESLineSearchVIProjectFunc projectfunc, SNESLineSearchVINormFunc normfunc)
1702: {
1703: PetscFunctionBegin;
1705: if (projectfunc) linesearch->ops->viproject = projectfunc;
1706: if (normfunc) linesearch->ops->vinorm = normfunc;
1707: PetscFunctionReturn(PETSC_SUCCESS);
1708: }
1710: /*@C
1711: SNESLineSearchGetVIFunctions - Sets VI-specific functions for line search computation.
1713: Not Collective
1715: Input Parameter:
1716: . linesearch - the line search context, obtain with `SNESGetLineSearch()`
1718: Output Parameters:
1719: + projectfunc - function for projecting the function to the bounds
1720: - normfunc - function for computing the norm of an active set
1722: Level: advanced
1724: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchSetVIFunctions()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchGetPreCheck()`
1725: @*/
1726: PetscErrorCode SNESLineSearchGetVIFunctions(SNESLineSearch linesearch, SNESLineSearchVIProjectFunc *projectfunc, SNESLineSearchVINormFunc *normfunc)
1727: {
1728: PetscFunctionBegin;
1729: if (projectfunc) *projectfunc = linesearch->ops->viproject;
1730: if (normfunc) *normfunc = linesearch->ops->vinorm;
1731: PetscFunctionReturn(PETSC_SUCCESS);
1732: }
1734: /*@C
1735: SNESLineSearchRegister - register a line search type `SNESLineSearchType`
1737: Input Parameters:
1738: + sname - name of the `SNESLineSearchType()`
1739: - function - the creation function for that type
1741: Calling sequence of `function`:
1742: . ls - the line search context
1744: Level: advanced
1746: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESLineSearchType`, `SNESLineSearchSetType()`
1747: @*/
1748: PetscErrorCode SNESLineSearchRegister(const char sname[], PetscErrorCode (*function)(SNESLineSearch ls))
1749: {
1750: PetscFunctionBegin;
1751: PetscCall(SNESInitializePackage());
1752: PetscCall(PetscFunctionListAdd(&SNESLineSearchList, sname, function));
1753: PetscFunctionReturn(PETSC_SUCCESS);
1754: }