Actual source code: linesearch.c
petsc-3.5.4 2015-05-23
1: #include <petsc-private/linesearchimpl.h> /*I "petscsnes.h" I*/
3: PetscBool SNESLineSearchRegisterAllCalled = PETSC_FALSE;
4: PetscFunctionList SNESLineSearchList = NULL;
6: PetscClassId SNESLINESEARCH_CLASSID;
7: PetscLogEvent SNESLineSearch_Apply;
11: /*@
12: SNESLineSearchCreate - Creates the line search context.
14: Logically Collective on Comm
16: Input Parameters:
17: . comm - MPI communicator for the line search (typically from the associated SNES context).
19: Output Parameters:
20: . outlinesearch - the new linesearch context
22: Level: developer
24: Notes:
25: The preferred calling sequence for users is to use SNESGetLineSearch() to acquire the SNESLineSearch instance
26: already associated with the SNES. This function is for developer use.
28: .keywords: LineSearch, create, context
30: .seealso: LineSearchDestroy(), SNESGetLineSearch()
31: @*/
33: PetscErrorCode SNESLineSearchCreate(MPI_Comm comm, SNESLineSearch *outlinesearch)
34: {
36: SNESLineSearch linesearch;
40: SNESInitializePackage();
41: *outlinesearch = NULL;
43: PetscHeaderCreate(linesearch,_p_LineSearch,struct _LineSearchOps,SNESLINESEARCH_CLASSID, "SNESLineSearch","Linesearch","SNESLineSearch",comm,SNESLineSearchDestroy,SNESLineSearchView);
45: linesearch->ops->precheck = NULL;
46: linesearch->ops->postcheck = NULL;
48: linesearch->vec_sol_new = NULL;
49: linesearch->vec_func_new = NULL;
50: linesearch->vec_sol = NULL;
51: linesearch->vec_func = NULL;
52: linesearch->vec_update = NULL;
54: linesearch->lambda = 1.0;
55: linesearch->fnorm = 1.0;
56: linesearch->ynorm = 1.0;
57: linesearch->xnorm = 1.0;
58: linesearch->success = PETSC_TRUE;
59: linesearch->norms = PETSC_TRUE;
60: linesearch->keeplambda = PETSC_FALSE;
61: linesearch->damping = 1.0;
62: linesearch->maxstep = 1e8;
63: linesearch->steptol = 1e-12;
64: linesearch->rtol = 1e-8;
65: linesearch->atol = 1e-15;
66: linesearch->ltol = 1e-8;
67: linesearch->precheckctx = NULL;
68: linesearch->postcheckctx = NULL;
69: linesearch->max_its = 1;
70: linesearch->setupcalled = PETSC_FALSE;
71: *outlinesearch = linesearch;
72: return(0);
73: }
77: /*@
78: SNESLineSearchSetUp - Prepares the line search for being applied by allocating
79: any required vectors.
81: Collective on SNESLineSearch
83: Input Parameters:
84: . linesearch - The LineSearch instance.
86: Notes:
87: For most cases, this needn't be called by users or outside of SNESLineSearchApply().
88: The only current case where this is called outside of this is for the VI
89: solvers, which modify the solution and work vectors before the first call
90: of SNESLineSearchApply, requiring the SNESLineSearch work vectors to be
91: allocated upfront.
93: Level: advanced
95: .keywords: SNESLineSearch, SetUp
97: .seealso: SNESLineSearchReset()
98: @*/
100: PetscErrorCode SNESLineSearchSetUp(SNESLineSearch linesearch)
101: {
105: if (!((PetscObject)linesearch)->type_name) {
106: SNESLineSearchSetType(linesearch,SNESLINESEARCHBASIC);
107: }
108: if (!linesearch->setupcalled) {
109: if (!linesearch->vec_sol_new) {
110: VecDuplicate(linesearch->vec_sol, &linesearch->vec_sol_new);
111: }
112: if (!linesearch->vec_func_new) {
113: VecDuplicate(linesearch->vec_sol, &linesearch->vec_func_new);
114: }
115: if (linesearch->ops->setup) {
116: (*linesearch->ops->setup)(linesearch);
117: }
118: if (!linesearch->ops->snesfunc) {SNESLineSearchSetFunction(linesearch,SNESComputeFunction);}
119: linesearch->lambda = linesearch->damping;
120: linesearch->setupcalled = PETSC_TRUE;
121: }
122: return(0);
123: }
128: /*@
129: SNESLineSearchReset - Undoes the SNESLineSearchSetUp() and deletes any Vecs or Mats allocated by the line search.
131: Collective on SNESLineSearch
133: Input Parameters:
134: . linesearch - The LineSearch instance.
136: Notes: Usually only called by SNESReset()
138: Level: developer
140: .keywords: SNESLineSearch, Reset
142: .seealso: SNESLineSearchSetUp()
143: @*/
145: PetscErrorCode SNESLineSearchReset(SNESLineSearch linesearch)
146: {
150: if (linesearch->ops->reset) (*linesearch->ops->reset)(linesearch);
152: VecDestroy(&linesearch->vec_sol_new);
153: VecDestroy(&linesearch->vec_func_new);
155: VecDestroyVecs(linesearch->nwork, &linesearch->work);
157: linesearch->nwork = 0;
158: linesearch->setupcalled = PETSC_FALSE;
159: return(0);
160: }
164: /*@C
165: SNESLineSearchSetFunction - Sets the function evaluation used by the SNES line search
167: Input Parameters:
168: . linesearch - the SNESLineSearch context
169: + func - function evaluation routine
171: Level: developer
173: Notes: This is used internally by PETSc and not called by users
175: .keywords: get, linesearch, pre-check
177: .seealso: SNESSetFunction()
178: @*/
179: PetscErrorCode SNESLineSearchSetFunction(SNESLineSearch linesearch, PetscErrorCode (*func)(SNES,Vec,Vec))
180: {
183: linesearch->ops->snesfunc = func;
184: return(0);
185: }
188: /*MC
189: SNESLineSearchPreCheckFunction - form of function passed to check the search direction before line search is called
191: Synopsis:
192: #include <petscsnes.h>
193: SNESLineSearchPreCheckFunction(SNESLineSearch snes,Vec x,Vec y, PetscBool *changed);
195: Input Parameters:
196: + x - solution vector
197: . y - search direction vector
198: - changed - flag to indicate the precheck changed x or y.
200: Note: This is NOTE a PETSc function, rather it documents the calling sequence of functions passed to SNESLineSearchSetPreCheck()
201: and SNESLineSearchGetPreCheck()
203: Level: advanced
205: .seealso: SNESLineSearchSetPreCheck(), SNESLineSearchGetPreCheck(), SNESLineSearchSetPostCheck(), SNESLineSearchGetPostCheck()
206: M*/
210: /*@C
211: SNESLineSearchSetPreCheck - Sets a user function that is called after the initial search direction has been computed but
212: before the line search routine has been applied. Allows the user to adjust the result of (usually a linear solve) that
213: determined the search direction.
215: Logically Collective on SNESLineSearch
217: Input Parameters:
218: + linesearch - the SNESLineSearch context
219: . func - [optional] function evaluation routine, see SNESLineSearchPreCheckFunction for the calling sequence
220: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be NULL)
222: Level: intermediate
224: .keywords: set, linesearch, pre-check
226: .seealso: SNESLineSearchSetPostCheck(), SNESLineSearchGetPostCheck(), SNESLineSearchGetPreCheck()
227: @*/
228: PetscErrorCode SNESLineSearchSetPreCheck(SNESLineSearch linesearch, PetscErrorCode (*func)(SNESLineSearch,Vec,Vec,PetscBool*,void*),void *ctx)
229: {
232: if (func) linesearch->ops->precheck = func;
233: if (ctx) linesearch->precheckctx = ctx;
234: return(0);
235: }
239: /*@C
240: SNESLineSearchSetPreCheck - Gets the pre-check function for the line search routine.
242: Input Parameters:
243: . linesearch - the SNESLineSearch context
245: Output Parameters:
246: + func - [optional] function evaluation routine, see SNESLineSearchPreCheckFunction for calling sequence
247: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be NULL)
249: Level: intermediate
251: .keywords: get, linesearch, pre-check
253: .seealso: SNESLineSearchGetPostCheck(), SNESLineSearchSetPreCheck()
254: @*/
255: PetscErrorCode SNESLineSearchGetPreCheck(SNESLineSearch linesearch, PetscErrorCode (**func)(SNESLineSearch,Vec,Vec,PetscBool*,void*),void **ctx)
256: {
259: if (func) *func = linesearch->ops->precheck;
260: if (ctx) *ctx = linesearch->precheckctx;
261: return(0);
262: }
264: /*MC
265: SNESLineSearchPostCheckFunction - form of function that is called after line search is complete
267: Synopsis:
268: #include <petscsnes.h>
269: SNESLineSearchPostheckFunction(SNESLineSearch linesearch,Vec x,Vec y, Vec w, *changed_y, PetscBool *changed_w);
271: Input Parameters:
272: + x - old solution vector
273: . y - search direction vector
274: . w - new solution vector
275: . changed_y - indicates that the line search changed y
276: - changed_w - indicates that the line search changed w
278: Note: This is NOTE a PETSc function, rather it documents the calling sequence of functions passed to SNESLineSearchSetPostCheck()
279: and SNESLineSearchGetPostCheck()
281: Level: advanced
283: .seealso: SNESLineSearchSetPreCheck(), SNESLineSearchSetPostCheck(), SNESLineSearchGetPreCheck(), SNESLineSearchGetPostCheck()
284: M*/
288: /*@C
289: SNESLineSearchSetPostCheck - Sets a user function that is called after the line search has been applied to determine the step
290: direction and length. Allows the user a chance to change or override the decision of the line search routine
292: Logically Collective on SNESLineSearch
294: Input Parameters:
295: + linesearch - the SNESLineSearch context
296: . func - [optional] function evaluation routine, see SNESLineSearchPostCheckFunction for the calling sequence
297: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be NULL)
299: Level: intermediate
301: .keywords: set, linesearch, post-check
303: .seealso: SNESLineSearchSetPreCheck()
304: @*/
305: PetscErrorCode SNESLineSearchSetPostCheck(SNESLineSearch linesearch, PetscErrorCode (*func)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*),void *ctx)
306: {
309: if (func) linesearch->ops->postcheck = func;
310: if (ctx) linesearch->postcheckctx = ctx;
311: return(0);
312: }
316: /*@C
317: SNESLineSearchGetPostCheck - Gets the post-check function for the line search routine.
319: Input Parameters:
320: . linesearch - the SNESLineSearch context
322: Output Parameters:
323: + func - [optional] function evaluation routine, see for the calling sequence SNESLineSearchPostCheckFunction
324: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be NULL)
326: Level: intermediate
328: .keywords: get, linesearch, post-check
330: .seealso: SNESLineSearchGetPreCheck(), SNESLineSearchSetPostCheck()
331: @*/
332: PetscErrorCode SNESLineSearchGetPostCheck(SNESLineSearch linesearch, PetscErrorCode (**func)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*),void **ctx)
333: {
336: if (func) *func = linesearch->ops->postcheck;
337: if (ctx) *ctx = linesearch->postcheckctx;
338: return(0);
339: }
343: /*@
344: SNESLineSearchPreCheck - Prepares the line search for being applied.
346: Logically Collective on SNESLineSearch
348: Input Parameters:
349: + linesearch - The linesearch instance.
350: . X - The current solution
351: - Y - The step direction
353: Output Parameters:
354: . changed - Indicator that the precheck routine has changed anything
356: Level: developer
358: .keywords: SNESLineSearch, Create
360: .seealso: SNESLineSearchPostCheck()
361: @*/
362: PetscErrorCode SNESLineSearchPreCheck(SNESLineSearch linesearch,Vec X,Vec Y,PetscBool *changed)
363: {
367: *changed = PETSC_FALSE;
368: if (linesearch->ops->precheck) {
369: (*linesearch->ops->precheck)(linesearch, X, Y, changed, linesearch->precheckctx);
371: }
372: return(0);
373: }
377: /*@
378: SNESLineSearchPostCheck - Prepares the line search for being applied.
380: Logically Collective on SNESLineSearch
382: Input Parameters:
383: + linesearch - The linesearch context
384: . X - The last solution
385: . Y - The step direction
386: - W - The updated solution, W = X + lambda*Y for some lambda
388: Output Parameters:
389: + changed_Y - Indicator if the direction Y has been changed.
390: - changed_W - Indicator if the new candidate solution W has been changed.
392: Level: developer
394: .keywords: SNESLineSearch, Create
396: .seealso: SNESLineSearchPreCheck()
397: @*/
398: PetscErrorCode SNESLineSearchPostCheck(SNESLineSearch linesearch,Vec X,Vec Y,Vec W,PetscBool *changed_Y,PetscBool *changed_W)
399: {
403: *changed_Y = PETSC_FALSE;
404: *changed_W = PETSC_FALSE;
405: if (linesearch->ops->postcheck) {
406: (*linesearch->ops->postcheck)(linesearch,X,Y,W,changed_Y,changed_W,linesearch->postcheckctx);
409: }
410: return(0);
411: }
415: /*@C
416: SNESLineSearchPreCheckPicard - Implements a correction that is sometimes useful to improve the convergence rate of Picard iteration
418: Logically Collective on SNESLineSearch
420: Input Arguments:
421: + linesearch - linesearch context
422: . X - base state for this step
423: . Y - initial correction
425: Output Arguments:
426: + Y - correction, possibly modified
427: - changed - flag indicating that Y was modified
429: Options Database Key:
430: + -snes_linesearch_precheck_picard - activate this routine
431: - -snes_linesearch_precheck_picard_angle - angle
433: Level: advanced
435: Notes:
436: This function should be passed to SNESLineSearchSetPreCheck()
438: The justification for this method involves the linear convergence of a Picard iteration
439: so the Picard linearization should be provided in place of the "Jacobian". This correction
440: is generally not useful when using a Newton linearization.
442: Reference:
443: Hindmarsh and Payne (1996) Time step limits for stable solutions of the ice sheet equation, Annals of Glaciology.
445: .seealso: SNESLineSearchSetPreCheck()
446: @*/
447: PetscErrorCode SNESLineSearchPreCheckPicard(SNESLineSearch linesearch,Vec X,Vec Y,PetscBool *changed,void *ctx)
448: {
450: PetscReal angle = *(PetscReal*)linesearch->precheckctx;
451: Vec Ylast;
452: PetscScalar dot;
453: PetscInt iter;
454: PetscReal ynorm,ylastnorm,theta,angle_radians;
455: SNES snes;
458: SNESLineSearchGetSNES(linesearch, &snes);
459: PetscObjectQuery((PetscObject)snes,"SNESLineSearchPreCheckPicard_Ylast",(PetscObject*)&Ylast);
460: if (!Ylast) {
461: VecDuplicate(Y,&Ylast);
462: PetscObjectCompose((PetscObject)snes,"SNESLineSearchPreCheckPicard_Ylast",(PetscObject)Ylast);
463: PetscObjectDereference((PetscObject)Ylast);
464: }
465: SNESGetIterationNumber(snes,&iter);
466: if (iter < 2) {
467: VecCopy(Y,Ylast);
468: *changed = PETSC_FALSE;
469: return(0);
470: }
472: VecDot(Y,Ylast,&dot);
473: VecNorm(Y,NORM_2,&ynorm);
474: VecNorm(Ylast,NORM_2,&ylastnorm);
475: /* Compute the angle between the vectors Y and Ylast, clip to keep inside the domain of acos() */
476: theta = PetscAcosReal((PetscReal)PetscClipInterval(PetscAbsScalar(dot) / (ynorm * ylastnorm),-1.0,1.0));
477: angle_radians = angle * PETSC_PI / 180.;
478: if (PetscAbsReal(theta) < angle_radians || PetscAbsReal(theta - PETSC_PI) < angle_radians) {
479: /* Modify the step Y */
480: PetscReal alpha,ydiffnorm;
481: VecAXPY(Ylast,-1.0,Y);
482: VecNorm(Ylast,NORM_2,&ydiffnorm);
483: alpha = ylastnorm / ydiffnorm;
484: VecCopy(Y,Ylast);
485: VecScale(Y,alpha);
486: PetscInfo3(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);
487: } else {
488: PetscInfo2(snes,"Angle %14.12e degrees exceeds threshold %14.12e, no correction applied\n",(double)(theta*180./PETSC_PI),(double)angle);
489: VecCopy(Y,Ylast);
490: *changed = PETSC_FALSE;
491: }
492: return(0);
493: }
497: /*@
498: SNESLineSearchApply - Computes the line-search update.
500: Collective on SNESLineSearch
502: Input Parameters:
503: + linesearch - The linesearch context
504: . X - The current solution
505: . F - The current function
506: . fnorm - The current norm
507: - Y - The search direction
509: Output Parameters:
510: + X - The new solution
511: . F - The new function
512: - fnorm - The new function norm
514: Options Database Keys:
515: + -snes_linesearch_type - basic, bt, l2, cp, shell
516: . -snes_linesearch_monitor - Print progress of line searches
517: . -snes_linesearch_damping - The linesearch damping parameter
518: . -snes_linesearch_norms - Turn on/off the linesearch norms
519: . -snes_linesearch_keeplambda - Keep the previous search length as the initial guess
520: - -snes_linesearch_max_it - The number of iterations for iterative line searches
522: Notes:
523: This is typically called from within a SNESSolve() implementation in order to
524: help with convergence of the nonlinear method. Various SNES types use line searches
525: in different ways, but the overarching theme is that a line search is used to determine
526: an optimal damping parameter of a step at each iteration of the method. Each
527: application of the line search may invoke SNESComputeFunction several times, and
528: therefore may be fairly expensive.
530: Level: Intermediate
532: .keywords: SNESLineSearch, Create
534: .seealso: SNESLineSearchCreate(), SNESLineSearchPreCheck(), SNESLineSearchPostCheck(), SNESSolve(), SNESComputeFunction()
535: @*/
536: PetscErrorCode SNESLineSearchApply(SNESLineSearch linesearch, Vec X, Vec F, PetscReal * fnorm, Vec Y)
537: {
546: linesearch->success = PETSC_TRUE;
548: linesearch->vec_sol = X;
549: linesearch->vec_update = Y;
550: linesearch->vec_func = F;
552: SNESLineSearchSetUp(linesearch);
554: if (!linesearch->keeplambda) linesearch->lambda = linesearch->damping; /* set the initial guess to lambda */
556: if (fnorm) linesearch->fnorm = *fnorm;
557: else {
558: VecNorm(F, NORM_2, &linesearch->fnorm);
559: }
561: PetscLogEventBegin(SNESLineSearch_Apply,linesearch,X,F,Y);
563: (*linesearch->ops->apply)(linesearch);
565: PetscLogEventEnd(SNESLineSearch_Apply,linesearch,X,F,Y);
567: if (fnorm) *fnorm = linesearch->fnorm;
568: return(0);
569: }
573: /*@
574: SNESLineSearchDestroy - Destroys the line search instance.
576: Collective on SNESLineSearch
578: Input Parameters:
579: . linesearch - The linesearch context
581: Level: Intermediate
583: .keywords: SNESLineSearch, Destroy
585: .seealso: SNESLineSearchCreate(), SNESLineSearchReset(), SNESDestroy()
586: @*/
587: PetscErrorCode SNESLineSearchDestroy(SNESLineSearch * linesearch)
588: {
592: if (!*linesearch) return(0);
594: if (--((PetscObject)(*linesearch))->refct > 0) {*linesearch = 0; return(0);}
595: PetscObjectSAWsViewOff((PetscObject)*linesearch);
596: SNESLineSearchReset(*linesearch);
597: if ((*linesearch)->ops->destroy) (*linesearch)->ops->destroy(*linesearch);
598: PetscViewerDestroy(&(*linesearch)->monitor);
599: PetscHeaderDestroy(linesearch);
600: return(0);
601: }
605: /*@
606: SNESLineSearchSetMonitor - Turns on/off printing useful information and debugging output about the line search.
608: Input Parameters:
609: + snes - nonlinear context obtained from SNESCreate()
610: - flg - PETSC_TRUE to monitor the line search
612: Logically Collective on SNES
614: Options Database:
615: . -snes_linesearch_monitor - enables the monitor
617: Level: intermediate
619: .seealso: SNESLineSearchGetMonitor(), PetscViewer
620: @*/
621: PetscErrorCode SNESLineSearchSetMonitor(SNESLineSearch linesearch, PetscBool flg)
622: {
626: if (flg && !linesearch->monitor) {
627: PetscViewerASCIIOpen(PetscObjectComm((PetscObject)linesearch),"stdout",&linesearch->monitor);
628: } else if (!flg && linesearch->monitor) {
629: PetscViewerDestroy(&linesearch->monitor);
630: }
631: return(0);
632: }
636: /*@
637: SNESLineSearchGetMonitor - Gets the PetscViewer instance for the line search monitor.
639: Input Parameter:
640: . linesearch - linesearch context
642: Output Parameter:
643: . monitor - monitor context
645: Logically Collective on SNES
647: Options Database Keys:
648: . -snes_linesearch_monitor - enables the monitor
650: Level: intermediate
652: .seealso: SNESLineSearchSetMonitor(), PetscViewer
653: @*/
654: PetscErrorCode SNESLineSearchGetMonitor(SNESLineSearch linesearch, PetscViewer *monitor)
655: {
658: if (monitor) {
660: *monitor = linesearch->monitor;
661: }
662: return(0);
663: }
667: /*@
668: SNESLineSearchSetFromOptions - Sets options for the line search
670: Input Parameters:
671: . linesearch - linesearch context
673: Options Database Keys:
674: + -snes_linesearch_type <type> - basic, bt, l2, cp, shell
675: . -snes_linesearch_order <order> - 1, 2, 3. Most types only support certain orders (bt supports 2 or 3)
676: . -snes_linesearch_norms - Turn on/off the linesearch norms for the basic linesearch type
677: . -snes_linesearch_minlambda - The minimum step length
678: . -snes_linesearch_maxstep - The maximum step size
679: . -snes_linesearch_rtol - Relative tolerance for iterative line searches
680: . -snes_linesearch_atol - Absolute tolerance for iterative line searches
681: . -snes_linesearch_ltol - Change in lambda tolerance for iterative line searches
682: . -snes_linesearch_max_it - The number of iterations for iterative line searches
683: . -snes_linesearch_monitor - Print progress of line searches
684: . -snes_linesearch_damping - The linesearch damping parameter
685: . -snes_linesearch_keeplambda - Keep the previous search length as the initial guess.
686: . -snes_linesearch_precheck_picard - Use precheck that speeds up convergence of picard method
687: - -snes_linesearch_precheck_picard_angle - Angle used in picard precheck method
689: Logically Collective on SNESLineSearch
691: Level: intermediate
693: .seealso: SNESLineSearchCreate(), SNESLineSearchSetOrder(), SNESLineSearchSetType(), SNESLineSearchSetTolerances(), SNESLineSearchSetDamping(), SNESLineSearchPreCheckPicard()
694: @*/
695: PetscErrorCode SNESLineSearchSetFromOptions(SNESLineSearch linesearch)
696: {
698: const char *deft = SNESLINESEARCHBASIC;
699: char type[256];
700: PetscBool flg, set;
703: if (!SNESLineSearchRegisterAllCalled) {SNESLineSearchRegisterAll();}
705: PetscObjectOptionsBegin((PetscObject)linesearch);
706: if (((PetscObject)linesearch)->type_name) deft = ((PetscObject)linesearch)->type_name;
707: PetscOptionsFList("-snes_linesearch_type","Linesearch type","SNESLineSearchSetType",SNESLineSearchList,deft,type,256,&flg);
708: if (flg) {
709: SNESLineSearchSetType(linesearch,type);
710: } else if (!((PetscObject)linesearch)->type_name) {
711: SNESLineSearchSetType(linesearch,deft);
712: }
714: PetscOptionsBool("-snes_linesearch_monitor","Print progress of line searches","SNESSNESLineSearchSetMonitor",
715: linesearch->monitor ? PETSC_TRUE : PETSC_FALSE,&flg,&set);
716: if (set) {SNESLineSearchSetMonitor(linesearch,flg);}
718: /* tolerances */
719: PetscOptionsReal("-snes_linesearch_minlambda","Minimum step length","SNESLineSearchSetTolerances",linesearch->steptol,&linesearch->steptol,0);
720: PetscOptionsReal("-snes_linesearch_maxstep","Maximum step size","SNESLineSearchSetTolerances",linesearch->maxstep,&linesearch->maxstep,0);
721: PetscOptionsReal("-snes_linesearch_rtol","Relative tolerance for iterative line search","SNESLineSearchSetTolerances",linesearch->rtol,&linesearch->rtol,0);
722: PetscOptionsReal("-snes_linesearch_atol","Absolute tolerance for iterative line search","SNESLineSearchSetTolerances",linesearch->atol,&linesearch->atol,0);
723: PetscOptionsReal("-snes_linesearch_ltol","Change in lambda tolerance for iterative line search","SNESLineSearchSetTolerances",linesearch->ltol,&linesearch->ltol,0);
724: PetscOptionsInt("-snes_linesearch_max_it","Maximum iterations for iterative line searches","SNESLineSearchSetTolerances",linesearch->max_its,&linesearch->max_its,0);
726: /* damping parameters */
727: PetscOptionsReal("-snes_linesearch_damping","Line search damping and initial step guess","SNESLineSearchSetDamping",linesearch->damping,&linesearch->damping,0);
729: PetscOptionsBool("-snes_linesearch_keeplambda","Use previous lambda as damping","SNESLineSearchSetKeepLambda",linesearch->keeplambda,&linesearch->keeplambda,0);
731: /* precheck */
732: PetscOptionsBool("-snes_linesearch_precheck_picard","Use a correction that sometimes improves convergence of Picard iteration","SNESLineSearchPreCheckPicard",flg,&flg,&set);
733: if (set) {
734: if (flg) {
735: linesearch->precheck_picard_angle = 10.; /* correction only active if angle is less than 10 degrees */
737: PetscOptionsReal("-snes_linesearch_precheck_picard_angle","Maximum angle at which to activate the correction",
738: "none",linesearch->precheck_picard_angle,&linesearch->precheck_picard_angle,NULL);
739: SNESLineSearchSetPreCheck(linesearch,SNESLineSearchPreCheckPicard,&linesearch->precheck_picard_angle);
740: } else {
741: SNESLineSearchSetPreCheck(linesearch,NULL,NULL);
742: }
743: }
744: PetscOptionsInt("-snes_linesearch_order","Order of approximation used in the line search","SNESLineSearchSetOrder",linesearch->order,&linesearch->order,0);
745: PetscOptionsBool("-snes_linesearch_norms","Compute final norms in line search","SNESLineSearchSetComputeNorms",linesearch->norms,&linesearch->norms,0);
747: if (linesearch->ops->setfromoptions) {
748: (*linesearch->ops->setfromoptions)(linesearch);
749: }
751: PetscObjectProcessOptionsHandlers((PetscObject)linesearch);
752: PetscOptionsEnd();
753: return(0);
754: }
758: /*@
759: SNESLineSearchView - Prints useful information about the line search
761: Input Parameters:
762: . linesearch - linesearch context
764: Logically Collective on SNESLineSearch
766: Level: intermediate
768: .seealso: SNESLineSearchCreate(), SNESLineSearchMonitor()
769: @*/
770: PetscErrorCode SNESLineSearchView(SNESLineSearch linesearch, PetscViewer viewer)
771: {
773: PetscBool iascii;
777: if (!viewer) {
778: PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)linesearch),&viewer);
779: }
783: PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
784: if (iascii) {
785: PetscObjectPrintClassNamePrefixType((PetscObject)linesearch,viewer);
786: if (linesearch->ops->view) {
787: PetscViewerASCIIPushTab(viewer);
788: (*linesearch->ops->view)(linesearch,viewer);
789: PetscViewerASCIIPopTab(viewer);
790: }
791: PetscViewerASCIIPrintf(viewer," maxstep=%e, minlambda=%e\n", (double)linesearch->maxstep,(double)linesearch->steptol);
792: PetscViewerASCIIPrintf(viewer," tolerances: relative=%e, absolute=%e, lambda=%e\n", (double)linesearch->rtol,(double)linesearch->atol,(double)linesearch->ltol);
793: PetscViewerASCIIPrintf(viewer," maximum iterations=%D\n", linesearch->max_its);
794: if (linesearch->ops->precheck) {
795: if (linesearch->ops->precheck == SNESLineSearchPreCheckPicard) {
796: PetscViewerASCIIPrintf(viewer," using precheck step to speed up Picard convergence\n", linesearch->max_its);
797: } else {
798: PetscViewerASCIIPrintf(viewer," using user-defined precheck step\n", linesearch->max_its);
799: }
800: }
801: if (linesearch->ops->postcheck) {
802: PetscViewerASCIIPrintf(viewer," using user-defined postcheck step\n", linesearch->max_its);
803: }
804: }
805: return(0);
806: }
810: /*@C
811: SNESLineSearchSetType - Sets the linesearch type
813: Logically Collective on SNESLineSearch
815: Input Parameters:
816: + linesearch - linesearch context
817: - type - The type of line search to be used
819: Available Types:
820: + basic - Simple damping line search.
821: . bt - Backtracking line search over the L2 norm of the function
822: . l2 - Secant line search over the L2 norm of the function
823: . cp - Critical point secant line search assuming F(x) = grad G(x) for some unknown G(x)
824: - shell - User provided SNESLineSearch implementation
826: Level: intermediate
828: .seealso: SNESLineSearchCreate()
829: @*/
830: PetscErrorCode SNESLineSearchSetType(SNESLineSearch linesearch, SNESLineSearchType type)
831: {
832: PetscErrorCode ierr,(*r)(SNESLineSearch);
833: PetscBool match;
839: PetscObjectTypeCompare((PetscObject)linesearch,type,&match);
840: if (match) return(0);
842: PetscFunctionListFind(SNESLineSearchList,type,&r);
843: if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested Line Search type %s",type);
844: /* Destroy the previous private linesearch context */
845: if (linesearch->ops->destroy) {
846: (*(linesearch)->ops->destroy)(linesearch);
848: linesearch->ops->destroy = NULL;
849: }
850: /* Reinitialize function pointers in SNESLineSearchOps structure */
851: linesearch->ops->apply = 0;
852: linesearch->ops->view = 0;
853: linesearch->ops->setfromoptions = 0;
854: linesearch->ops->destroy = 0;
856: PetscObjectChangeTypeName((PetscObject)linesearch,type);
857: (*r)(linesearch);
858: return(0);
859: }
863: /*@
864: SNESLineSearchSetSNES - Sets the SNES for the linesearch for function evaluation.
866: Input Parameters:
867: + linesearch - linesearch context
868: - snes - The snes instance
870: Level: developer
872: Notes:
873: This happens automatically when the line search is obtained/created with
874: SNESGetLineSearch(). This routine is therefore mainly called within SNES
875: implementations.
877: Level: developer
879: .seealso: SNESLineSearchGetSNES(), SNESLineSearchSetVecs(), SNES
880: @*/
881: PetscErrorCode SNESLineSearchSetSNES(SNESLineSearch linesearch, SNES snes)
882: {
886: linesearch->snes = snes;
887: return(0);
888: }
892: /*@
893: SNESLineSearchGetSNES - Gets the SNES instance associated with the line search.
894: Having an associated SNES is necessary because most line search implementations must be able to
895: evaluate the function using SNESComputeFunction() for the associated SNES. This routine
896: is used in the line search implementations when one must get this associated SNES instance.
898: Input Parameters:
899: . linesearch - linesearch context
901: Output Parameters:
902: . snes - The snes instance
904: Level: developer
906: .seealso: SNESLineSearchGetSNES(), SNESLineSearchSetVecs(), SNES
907: @*/
908: PetscErrorCode SNESLineSearchGetSNES(SNESLineSearch linesearch, SNES *snes)
909: {
913: *snes = linesearch->snes;
914: return(0);
915: }
919: /*@
920: SNESLineSearchGetLambda - Gets the last linesearch steplength discovered.
922: Input Parameters:
923: . linesearch - linesearch context
925: Output Parameters:
926: . lambda - The last steplength computed during SNESLineSearchApply()
928: Level: advanced
930: Notes:
931: This is useful in methods where the solver is ill-scaled and
932: requires some adaptive notion of the difference in scale between the
933: solution and the function. For instance, SNESQN may be scaled by the
934: line search lambda using the argument -snes_qn_scaling ls.
936: .seealso: SNESLineSearchSetLambda(), SNESLineSearchGetDamping(), SNESLineSearchApply()
937: @*/
938: PetscErrorCode SNESLineSearchGetLambda(SNESLineSearch linesearch,PetscReal *lambda)
939: {
943: *lambda = linesearch->lambda;
944: return(0);
945: }
949: /*@
950: SNESLineSearchSetLambda - Sets the linesearch steplength.
952: Input Parameters:
953: + linesearch - linesearch context
954: - lambda - The last steplength.
956: Notes:
957: This routine is typically used within implementations of SNESLineSearchApply()
958: to set the final steplength. This routine (and SNESLineSearchGetLambda()) were
959: added in order to facilitate Quasi-Newton methods that use the previous steplength
960: as an inner scaling parameter.
962: Level: advanced
964: .seealso: SNESLineSearchGetLambda()
965: @*/
966: PetscErrorCode SNESLineSearchSetLambda(SNESLineSearch linesearch, PetscReal lambda)
967: {
970: linesearch->lambda = lambda;
971: return(0);
972: }
974: #undef __FUNCT__
976: /*@
977: SNESLineSearchGetTolerances - Gets the tolerances for the linesearch. These include
978: tolerances for the relative and absolute change in the function norm, the change
979: in lambda for iterative line searches, the minimum steplength, the maximum steplength,
980: and the maximum number of iterations the line search procedure may take.
982: Input Parameters:
983: . linesearch - linesearch context
985: Output Parameters:
986: + steptol - The minimum steplength
987: . maxstep - The maximum steplength
988: . rtol - The relative tolerance for iterative line searches
989: . atol - The absolute tolerance for iterative line searches
990: . ltol - The change in lambda tolerance for iterative line searches
991: - max_it - The maximum number of iterations of the line search
993: Level: intermediate
995: Notes:
996: Different line searches may implement these parameters slightly differently as
997: the type requires.
999: .seealso: SNESLineSearchSetTolerances()
1000: @*/
1001: PetscErrorCode SNESLineSearchGetTolerances(SNESLineSearch linesearch,PetscReal *steptol,PetscReal *maxstep, PetscReal *rtol, PetscReal *atol, PetscReal *ltol, PetscInt *max_its)
1002: {
1005: if (steptol) {
1007: *steptol = linesearch->steptol;
1008: }
1009: if (maxstep) {
1011: *maxstep = linesearch->maxstep;
1012: }
1013: if (rtol) {
1015: *rtol = linesearch->rtol;
1016: }
1017: if (atol) {
1019: *atol = linesearch->atol;
1020: }
1021: if (ltol) {
1023: *ltol = linesearch->ltol;
1024: }
1025: if (max_its) {
1027: *max_its = linesearch->max_its;
1028: }
1029: return(0);
1030: }
1032: #undef __FUNCT__
1034: /*@
1035: SNESLineSearchSetTolerances - Gets the tolerances for the linesearch. These include
1036: tolerances for the relative and absolute change in the function norm, the change
1037: in lambda for iterative line searches, the minimum steplength, the maximum steplength,
1038: and the maximum number of iterations the line search procedure may take.
1040: Input Parameters:
1041: + linesearch - linesearch context
1042: . steptol - The minimum steplength
1043: . maxstep - The maximum steplength
1044: . rtol - The relative tolerance for iterative line searches
1045: . atol - The absolute tolerance for iterative line searches
1046: . ltol - The change in lambda tolerance for iterative line searches
1047: - max_it - The maximum number of iterations of the line search
1049: Notes:
1050: The user may choose to not set any of the tolerances using PETSC_DEFAULT in
1051: place of an argument.
1053: Level: intermediate
1055: .seealso: SNESLineSearchGetTolerances()
1056: @*/
1057: PetscErrorCode SNESLineSearchSetTolerances(SNESLineSearch linesearch,PetscReal steptol,PetscReal maxstep, PetscReal rtol, PetscReal atol, PetscReal ltol, PetscInt max_its)
1058: {
1068: if (steptol!= PETSC_DEFAULT) {
1069: if (steptol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)linesearch),PETSC_ERR_ARG_OUTOFRANGE,"Minimum step length %14.12e must be non-negative",(double)steptol);
1070: linesearch->steptol = steptol;
1071: }
1073: if (maxstep!= PETSC_DEFAULT) {
1074: if (maxstep < 0.0) SETERRQ1(PetscObjectComm((PetscObject)linesearch),PETSC_ERR_ARG_OUTOFRANGE,"Maximum step length %14.12e must be non-negative",(double)maxstep);
1075: linesearch->maxstep = maxstep;
1076: }
1078: if (rtol != PETSC_DEFAULT) {
1079: if (rtol < 0.0 || 1.0 <= rtol) SETERRQ1(PetscObjectComm((PetscObject)linesearch),PETSC_ERR_ARG_OUTOFRANGE,"Relative tolerance %14.12e must be non-negative and less than 1.0",(double)rtol);
1080: linesearch->rtol = rtol;
1081: }
1083: if (atol != PETSC_DEFAULT) {
1084: if (atol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)linesearch),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %14.12e must be non-negative",(double)atol);
1085: linesearch->atol = atol;
1086: }
1088: if (ltol != PETSC_DEFAULT) {
1089: if (ltol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)linesearch),PETSC_ERR_ARG_OUTOFRANGE,"Labmda tolerance %14.12e must be non-negative",(double)ltol);
1090: linesearch->ltol = ltol;
1091: }
1093: if (max_its != PETSC_DEFAULT) {
1094: if (max_its < 0) SETERRQ1(PetscObjectComm((PetscObject)linesearch),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",max_its);
1095: linesearch->max_its = max_its;
1096: }
1097: return(0);
1098: }
1102: /*@
1103: SNESLineSearchGetDamping - Gets the line search damping parameter.
1105: Input Parameters:
1106: . linesearch - linesearch context
1108: Output Parameters:
1109: . damping - The damping parameter
1111: Level: advanced
1113: .seealso: SNESLineSearchGetStepTolerance(), SNESQN
1114: @*/
1116: PetscErrorCode SNESLineSearchGetDamping(SNESLineSearch linesearch,PetscReal *damping)
1117: {
1121: *damping = linesearch->damping;
1122: return(0);
1123: }
1127: /*@
1128: SNESLineSearchSetDamping - Sets the line search damping paramter.
1130: Input Parameters:
1131: . linesearch - linesearch context
1132: . damping - The damping parameter
1134: Level: intermediate
1136: Notes:
1137: The basic line search merely takes the update step scaled by the damping parameter.
1138: The use of the damping parameter in the l2 and cp line searches is much more subtle;
1139: it is used as a starting point in calculating the secant step. However, the eventual
1140: step may be of greater length than the damping parameter. In the bt line search it is
1141: used as the maximum possible step length, as the bt line search only backtracks.
1143: .seealso: SNESLineSearchGetDamping()
1144: @*/
1145: PetscErrorCode SNESLineSearchSetDamping(SNESLineSearch linesearch,PetscReal damping)
1146: {
1149: linesearch->damping = damping;
1150: return(0);
1151: }
1155: /*@
1156: SNESLineSearchGetOrder - Gets the line search approximation order.
1158: Input Parameters:
1159: . linesearch - linesearch context
1161: Output Parameters:
1162: . order - The order
1164: Possible Values for order:
1165: + 1 or SNES_LINESEARCH_ORDER_LINEAR - linear order
1166: . 2 or SNES_LINESEARCH_ORDER_QUADRATIC - quadratic order
1167: - 3 or SNES_LINESEARCH_ORDER_CUBIC - cubic order
1169: Level: intermediate
1171: .seealso: SNESLineSearchSetOrder()
1172: @*/
1174: PetscErrorCode SNESLineSearchGetOrder(SNESLineSearch linesearch,PetscInt *order)
1175: {
1179: *order = linesearch->order;
1180: return(0);
1181: }
1185: /*@
1186: SNESLineSearchSetOrder - Sets the line search damping paramter.
1188: Input Parameters:
1189: . linesearch - linesearch context
1190: . order - The damping parameter
1192: Level: intermediate
1194: Possible Values for order:
1195: + 1 or SNES_LINESEARCH_ORDER_LINEAR - linear order
1196: . 2 or SNES_LINESEARCH_ORDER_QUADRATIC - quadratic order
1197: - 3 or SNES_LINESEARCH_ORDER_CUBIC - cubic order
1199: Notes:
1200: Variable orders are supported by the following line searches:
1201: + bt - cubic and quadratic
1202: - cp - linear and quadratic
1204: .seealso: SNESLineSearchGetOrder()
1205: @*/
1206: PetscErrorCode SNESLineSearchSetOrder(SNESLineSearch linesearch,PetscInt order)
1207: {
1210: linesearch->order = order;
1211: return(0);
1212: }
1216: /*@
1217: SNESLineSearchGetNorms - Gets the norms for for X, Y, and F.
1219: Input Parameters:
1220: . linesearch - linesearch context
1222: Output Parameters:
1223: + xnorm - The norm of the current solution
1224: . fnorm - The norm of the current function
1225: - ynorm - The norm of the current update
1227: Notes:
1228: This function is mainly called from SNES implementations.
1230: Level: developer
1232: .seealso: SNESLineSearchSetNorms() SNESLineSearchGetVecs()
1233: @*/
1234: PetscErrorCode SNESLineSearchGetNorms(SNESLineSearch linesearch, PetscReal * xnorm, PetscReal * fnorm, PetscReal * ynorm)
1235: {
1238: if (xnorm) *xnorm = linesearch->xnorm;
1239: if (fnorm) *fnorm = linesearch->fnorm;
1240: if (ynorm) *ynorm = linesearch->ynorm;
1241: return(0);
1242: }
1246: /*@
1247: SNESLineSearchSetNorms - Gets the computed norms for for X, Y, and F.
1249: Input Parameters:
1250: + linesearch - linesearch context
1251: . xnorm - The norm of the current solution
1252: . fnorm - The norm of the current function
1253: - ynorm - The norm of the current update
1255: Level: advanced
1257: .seealso: SNESLineSearchGetNorms(), SNESLineSearchSetVecs()
1258: @*/
1259: PetscErrorCode SNESLineSearchSetNorms(SNESLineSearch linesearch, PetscReal xnorm, PetscReal fnorm, PetscReal ynorm)
1260: {
1263: linesearch->xnorm = xnorm;
1264: linesearch->fnorm = fnorm;
1265: linesearch->ynorm = ynorm;
1266: return(0);
1267: }
1271: /*@
1272: SNESLineSearchComputeNorms - Computes the norms of X, F, and Y.
1274: Input Parameters:
1275: . linesearch - linesearch context
1277: Options Database Keys:
1278: . -snes_linesearch_norms - turn norm computation on or off
1280: Level: intermediate
1282: .seealso: SNESLineSearchGetNorms, SNESLineSearchSetNorms(), SNESLineSearchSetComputeNorms()
1283: @*/
1284: PetscErrorCode SNESLineSearchComputeNorms(SNESLineSearch linesearch)
1285: {
1287: SNES snes;
1290: if (linesearch->norms) {
1291: if (linesearch->ops->vinorm) {
1292: SNESLineSearchGetSNES(linesearch, &snes);
1293: VecNorm(linesearch->vec_sol, NORM_2, &linesearch->xnorm);
1294: VecNorm(linesearch->vec_update, NORM_2, &linesearch->ynorm);
1295: (*linesearch->ops->vinorm)(snes, linesearch->vec_func, linesearch->vec_sol, &linesearch->fnorm);
1296: } else {
1297: VecNormBegin(linesearch->vec_func, NORM_2, &linesearch->fnorm);
1298: VecNormBegin(linesearch->vec_sol, NORM_2, &linesearch->xnorm);
1299: VecNormBegin(linesearch->vec_update, NORM_2, &linesearch->ynorm);
1300: VecNormEnd(linesearch->vec_func, NORM_2, &linesearch->fnorm);
1301: VecNormEnd(linesearch->vec_sol, NORM_2, &linesearch->xnorm);
1302: VecNormEnd(linesearch->vec_update, NORM_2, &linesearch->ynorm);
1303: }
1304: }
1305: return(0);
1306: }
1310: /*@
1311: SNESLineSearchSetComputeNorms - Turns on or off the computation of final norms in the line search.
1313: Input Parameters:
1314: + linesearch - linesearch context
1315: - flg - indicates whether or not to compute norms
1317: Options Database Keys:
1318: . -snes_linesearch_norms - turn norm computation on or off
1320: Notes:
1321: This is most relevant to the SNESLINESEARCHBASIC line search type.
1323: Level: intermediate
1325: .seealso: SNESLineSearchGetNorms(), SNESLineSearchSetNorms(), SNESLineSearchComputeNorms(), SNESLINESEARCHBASIC
1326: @*/
1327: PetscErrorCode SNESLineSearchSetComputeNorms(SNESLineSearch linesearch, PetscBool flg)
1328: {
1330: linesearch->norms = flg;
1331: return(0);
1332: }
1336: /*@
1337: SNESLineSearchGetVecs - Gets the vectors from the SNESLineSearch context
1339: Input Parameters:
1340: . linesearch - linesearch context
1342: Output Parameters:
1343: + X - Solution vector
1344: . F - Function vector
1345: . Y - Search direction vector
1346: . W - Solution work vector
1347: - G - Function work vector
1349: Notes:
1350: At the beginning of a line search application, X should contain a
1351: solution and the vector F the function computed at X. At the end of the
1352: line search application, X should contain the new solution, and F the
1353: function evaluated at the new solution.
1355: Level: advanced
1357: .seealso: SNESLineSearchGetNorms(), SNESLineSearchSetVecs()
1358: @*/
1359: PetscErrorCode SNESLineSearchGetVecs(SNESLineSearch linesearch,Vec *X,Vec *F, Vec *Y,Vec *W,Vec *G)
1360: {
1363: if (X) {
1365: *X = linesearch->vec_sol;
1366: }
1367: if (F) {
1369: *F = linesearch->vec_func;
1370: }
1371: if (Y) {
1373: *Y = linesearch->vec_update;
1374: }
1375: if (W) {
1377: *W = linesearch->vec_sol_new;
1378: }
1379: if (G) {
1381: *G = linesearch->vec_func_new;
1382: }
1383: return(0);
1384: }
1388: /*@
1389: SNESLineSearchSetVecs - Sets the vectors on the SNESLineSearch context
1391: Input Parameters:
1392: + linesearch - linesearch context
1393: . X - Solution vector
1394: . F - Function vector
1395: . Y - Search direction vector
1396: . W - Solution work vector
1397: - G - Function work vector
1399: Level: advanced
1401: .seealso: SNESLineSearchSetNorms(), SNESLineSearchGetVecs()
1402: @*/
1403: PetscErrorCode SNESLineSearchSetVecs(SNESLineSearch linesearch,Vec X,Vec F,Vec Y,Vec W, Vec G)
1404: {
1407: if (X) {
1409: linesearch->vec_sol = X;
1410: }
1411: if (F) {
1413: linesearch->vec_func = F;
1414: }
1415: if (Y) {
1417: linesearch->vec_update = Y;
1418: }
1419: if (W) {
1421: linesearch->vec_sol_new = W;
1422: }
1423: if (G) {
1425: linesearch->vec_func_new = G;
1426: }
1427: return(0);
1428: }
1432: /*@C
1433: SNESLineSearchAppendOptionsPrefix - Appends to the prefix used for searching for all
1434: SNES options in the database.
1436: Logically Collective on SNESLineSearch
1438: Input Parameters:
1439: + snes - the SNES context
1440: - prefix - the prefix to prepend to all option names
1442: Notes:
1443: A hyphen (-) must NOT be given at the beginning of the prefix name.
1444: The first character of all runtime options is AUTOMATICALLY the hyphen.
1446: Level: advanced
1448: .keywords: SNESLineSearch, append, options, prefix, database
1450: .seealso: SNESGetOptionsPrefix()
1451: @*/
1452: PetscErrorCode SNESLineSearchAppendOptionsPrefix(SNESLineSearch linesearch,const char prefix[])
1453: {
1458: PetscObjectAppendOptionsPrefix((PetscObject)linesearch,prefix);
1459: return(0);
1460: }
1464: /*@C
1465: SNESLineSearchGetOptionsPrefix - Sets the prefix used for searching for all
1466: SNESLineSearch options in the database.
1468: Not Collective
1470: Input Parameter:
1471: . linesearch - the SNESLineSearch context
1473: Output Parameter:
1474: . prefix - pointer to the prefix string used
1476: Notes:
1477: On the fortran side, the user should pass in a string 'prefix' of
1478: sufficient length to hold the prefix.
1480: Level: advanced
1482: .keywords: SNESLineSearch, get, options, prefix, database
1484: .seealso: SNESAppendOptionsPrefix()
1485: @*/
1486: PetscErrorCode SNESLineSearchGetOptionsPrefix(SNESLineSearch linesearch,const char *prefix[])
1487: {
1492: PetscObjectGetOptionsPrefix((PetscObject)linesearch,prefix);
1493: return(0);
1494: }
1498: /*@C
1499: SNESLineSearchSetWorkVecs - Gets work vectors for the line search.
1501: Input Parameter:
1502: + linesearch - the SNESLineSearch context
1503: - nwork - the number of work vectors
1505: Level: developer
1507: Developers Note: This is PETSC_EXTERN because it may be used by user written plugin SNES implementations
1509: .keywords: SNESLineSearch, work, vector
1511: .seealso: SNESSetWorkVecs()
1512: @*/
1513: PetscErrorCode SNESLineSearchSetWorkVecs(SNESLineSearch linesearch, PetscInt nwork)
1514: {
1518: if (linesearch->vec_sol) {
1519: VecDuplicateVecs(linesearch->vec_sol, nwork, &linesearch->work);
1520: } else SETERRQ(PetscObjectComm((PetscObject)linesearch), PETSC_ERR_USER, "Cannot get linesearch work-vectors without setting a solution vec!");
1521: return(0);
1522: }
1526: /*@
1527: SNESLineSearchGetSuccess - Gets the success/failure status of the last line search application
1529: Input Parameters:
1530: . linesearch - linesearch context
1532: Output Parameters:
1533: . success - The success or failure status
1535: Notes:
1536: This is typically called after SNESLineSearchApply() in order to determine if the line-search failed
1537: (and set the SNES convergence accordingly).
1539: Level: intermediate
1541: .seealso: SNESLineSearchSetSuccess()
1542: @*/
1543: PetscErrorCode SNESLineSearchGetSuccess(SNESLineSearch linesearch, PetscBool *success)
1544: {
1548: if (success) *success = linesearch->success;
1549: return(0);
1550: }
1554: /*@
1555: SNESLineSearchSetSuccess - Sets the success/failure status of the last line search application
1557: Input Parameters:
1558: + linesearch - linesearch context
1559: - success - The success or failure status
1561: Notes:
1562: This is typically called in a SNESLineSearchApply() or SNESLineSearchShell implementation to set
1563: the success or failure of the line search method.
1565: Level: developer
1567: .seealso: SNESLineSearchGetSuccess()
1568: @*/
1569: PetscErrorCode SNESLineSearchSetSuccess(SNESLineSearch linesearch, PetscBool success)
1570: {
1573: linesearch->success = success;
1574: return(0);
1575: }
1579: /*@C
1580: SNESLineSearchSetVIFunctions - Sets VI-specific functions for line search computation.
1582: Input Parameters:
1583: + snes - nonlinear context obtained from SNESCreate()
1584: . projectfunc - function for projecting the function to the bounds
1585: - normfunc - function for computing the norm of an active set
1587: Logically Collective on SNES
1589: Calling sequence of projectfunc:
1590: .vb
1591: projectfunc (SNES snes, Vec X)
1592: .ve
1594: Input parameters for projectfunc:
1595: + snes - nonlinear context
1596: - X - current solution
1598: Output parameters for projectfunc:
1599: . X - Projected solution
1601: Calling sequence of normfunc:
1602: .vb
1603: projectfunc (SNES snes, Vec X, Vec F, PetscScalar * fnorm)
1604: .ve
1606: Input parameters for normfunc:
1607: + snes - nonlinear context
1608: . X - current solution
1609: - F - current residual
1611: Output parameters for normfunc:
1612: . fnorm - VI-specific norm of the function
1614: Notes:
1615: The VI solvers require projection of the solution to the feasible set. projectfunc should implement this.
1617: The VI solvers require special evaluation of the function norm such that the norm is only calculated
1618: on the inactive set. This should be implemented by normfunc.
1620: Level: developer
1622: .keywords: SNES, line search, VI, nonlinear, set, line search
1624: .seealso: SNESLineSearchGetVIFunctions(), SNESLineSearchSetPostCheck(), SNESLineSearchSetPreCheck()
1625: @*/
1626: extern PetscErrorCode SNESLineSearchSetVIFunctions(SNESLineSearch linesearch, SNESLineSearchVIProjectFunc projectfunc, SNESLineSearchVINormFunc normfunc)
1627: {
1630: if (projectfunc) linesearch->ops->viproject = projectfunc;
1631: if (normfunc) linesearch->ops->vinorm = normfunc;
1632: return(0);
1633: }
1637: /*@C
1638: SNESLineSearchGetVIFunctions - Sets VI-specific functions for line search computation.
1640: Input Parameters:
1641: . snes - nonlinear context obtained from SNESCreate()
1643: Output Parameters:
1644: + projectfunc - function for projecting the function to the bounds
1645: - normfunc - function for computing the norm of an active set
1647: Logically Collective on SNES
1649: Level: developer
1651: .keywords: SNES, line search, VI, nonlinear, get, line search
1653: .seealso: SNESLineSearchSetVIFunctions(), SNESLineSearchGetPostCheck(), SNESLineSearchGetPreCheck()
1654: @*/
1655: extern PetscErrorCode SNESLineSearchGetVIFunctions(SNESLineSearch linesearch, SNESLineSearchVIProjectFunc *projectfunc, SNESLineSearchVINormFunc *normfunc)
1656: {
1658: if (projectfunc) *projectfunc = linesearch->ops->viproject;
1659: if (normfunc) *normfunc = linesearch->ops->vinorm;
1660: return(0);
1661: }
1665: /*@C
1666: SNESLineSearchRegister - See SNESLineSearchRegister()
1668: Level: advanced
1669: @*/
1670: PetscErrorCode SNESLineSearchRegister(const char sname[],PetscErrorCode (*function)(SNESLineSearch))
1671: {
1675: PetscFunctionListAdd(&SNESLineSearchList,sname,function);
1676: return(0);
1677: }