Actual source code: snes.c
1: #define PETSCSNES_DLL
3: #include include/private/snesimpl.h
5: PetscTruth SNESRegisterAllCalled = PETSC_FALSE;
6: PetscFList SNESList = PETSC_NULL;
8: /* Logging support */
9: PetscCookie SNES_COOKIE = 0;
10: PetscEvent SNES_Solve = 0, SNES_LineSearch = 0, SNES_FunctionEval = 0, SNES_JacobianEval = 0;
14: /*@C
15: SNESView - Prints the SNES data structure.
17: Collective on SNES
19: Input Parameters:
20: + SNES - the SNES context
21: - viewer - visualization context
23: Options Database Key:
24: . -snes_view - Calls SNESView() at end of SNESSolve()
26: Notes:
27: The available visualization contexts include
28: + PETSC_VIEWER_STDOUT_SELF - standard output (default)
29: - PETSC_VIEWER_STDOUT_WORLD - synchronized standard
30: output where only the first processor opens
31: the file. All other processors send their
32: data to the first processor to print.
34: The user can open an alternative visualization context with
35: PetscViewerASCIIOpen() - output to a specified file.
37: Level: beginner
39: .keywords: SNES, view
41: .seealso: PetscViewerASCIIOpen()
42: @*/
43: PetscErrorCode SNESView(SNES snes,PetscViewer viewer)
44: {
45: SNES_KSP_EW_ConvCtx *kctx;
46: PetscErrorCode ierr;
47: KSP ksp;
48: SNESType type;
49: PetscTruth iascii,isstring;
53: if (!viewer) {
54: PetscViewerASCIIGetStdout(snes->comm,&viewer);
55: }
59: PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);
60: PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_STRING,&isstring);
61: if (iascii) {
62: if (snes->prefix) {
63: PetscViewerASCIIPrintf(viewer,"SNES Object:(%s)\n",snes->prefix);
64: } else {
65: PetscViewerASCIIPrintf(viewer,"SNES Object:\n");
66: }
67: SNESGetType(snes,&type);
68: if (type) {
69: PetscViewerASCIIPrintf(viewer," type: %s\n",type);
70: } else {
71: PetscViewerASCIIPrintf(viewer," type: not set yet\n");
72: }
73: if (snes->ops->view) {
74: PetscViewerASCIIPushTab(viewer);
75: (*snes->ops->view)(snes,viewer);
76: PetscViewerASCIIPopTab(viewer);
77: }
78: PetscViewerASCIIPrintf(viewer," maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
79: PetscViewerASCIIPrintf(viewer," tolerances: relative=%G, absolute=%G, solution=%G\n",
80: snes->rtol,snes->abstol,snes->xtol);
81: PetscViewerASCIIPrintf(viewer," total number of linear solver iterations=%D\n",snes->linear_its);
82: PetscViewerASCIIPrintf(viewer," total number of function evaluations=%D\n",snes->nfuncs);
83: if (snes->ksp_ewconv) {
84: kctx = (SNES_KSP_EW_ConvCtx *)snes->kspconvctx;
85: if (kctx) {
86: PetscViewerASCIIPrintf(viewer," Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
87: PetscViewerASCIIPrintf(viewer," rtol_0=%G, rtol_max=%G, threshold=%G\n",kctx->rtol_0,kctx->rtol_max,kctx->threshold);
88: PetscViewerASCIIPrintf(viewer," gamma=%G, alpha=%G, alpha2=%G\n",kctx->gamma,kctx->alpha,kctx->alpha2);
89: }
90: }
91: } else if (isstring) {
92: SNESGetType(snes,&type);
93: PetscViewerStringSPrintf(viewer," %-3.3s",type);
94: }
95: SNESGetKSP(snes,&ksp);
96: PetscViewerASCIIPushTab(viewer);
97: KSPView(ksp,viewer);
98: PetscViewerASCIIPopTab(viewer);
99: return(0);
100: }
102: /*
103: We retain a list of functions that also take SNES command
104: line options. These are called at the end SNESSetFromOptions()
105: */
106: #define MAXSETFROMOPTIONS 5
107: static PetscInt numberofsetfromoptions;
108: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);
112: /*@C
113: SNESAddOptionsChecker - Adds an additional function to check for SNES options.
115: Not Collective
117: Input Parameter:
118: . snescheck - function that checks for options
120: Level: developer
122: .seealso: SNESSetFromOptions()
123: @*/
124: PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
125: {
127: if (numberofsetfromoptions >= MAXSETFROMOPTIONS) {
128: SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
129: }
130: othersetfromoptions[numberofsetfromoptions++] = snescheck;
131: return(0);
132: }
136: /*@
137: SNESSetFromOptions - Sets various SNES and KSP parameters from user options.
139: Collective on SNES
141: Input Parameter:
142: . snes - the SNES context
144: Options Database Keys:
145: + -snes_type <type> - ls, tr, umls, umtr, test
146: . -snes_stol - convergence tolerance in terms of the norm
147: of the change in the solution between steps
148: . -snes_atol <abstol> - absolute tolerance of residual norm
149: . -snes_rtol <rtol> - relative decrease in tolerance norm from initial
150: . -snes_max_it <max_it> - maximum number of iterations
151: . -snes_max_funcs <max_funcs> - maximum number of function evaluations
152: . -snes_max_fail <max_fail> - maximum number of failures
153: . -snes_trtol <trtol> - trust region tolerance
154: . -snes_no_convergence_test - skip convergence test in nonlinear
155: solver; hence iterations will continue until max_it
156: or some other criterion is reached. Saves expense
157: of convergence test
158: . -snes_monitor <optional filename> - prints residual norm at each iteration. if no
159: filename given prints to stdout
160: . -snes_monitor_solution - plots solution at each iteration
161: . -snes_monitor_residual - plots residual (not its norm) at each iteration
162: . -snes_monitor_solution_update - plots update to solution at each iteration
163: . -snes_monitor_draw - plots residual norm at each iteration
164: . -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
165: . -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
166: - -snes_converged_reason - print the reason for convergence/divergence after each solve
168: Options Database for Eisenstat-Walker method:
169: + -snes_ksp_ew_conv - use Eisenstat-Walker method for determining linear system convergence
170: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
171: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
172: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
173: . -snes_ksp_ew_gamma <gamma> - Sets gamma
174: . -snes_ksp_ew_alpha <alpha> - Sets alpha
175: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
176: - -snes_ksp_ew_threshold <threshold> - Sets threshold
178: Notes:
179: To see all options, run your program with the -help option or consult
180: the users manual.
182: Level: beginner
184: .keywords: SNES, nonlinear, set, options, database
186: .seealso: SNESSetOptionsPrefix()
187: @*/
188: PetscErrorCode SNESSetFromOptions(SNES snes)
189: {
190: KSP ksp;
191: SNES_KSP_EW_ConvCtx *kctx = (SNES_KSP_EW_ConvCtx *)snes->kspconvctx;
192: PetscTruth flg;
193: PetscErrorCode ierr;
194: PetscInt i;
195: const char *deft;
196: char type[256], monfilename[PETSC_MAX_PATH_LEN];
197: PetscViewerASCIIMonitor monviewer;
202: PetscOptionsBegin(snes->comm,snes->prefix,"Nonlinear solver (SNES) options","SNES");
203: if (snes->type_name) {
204: deft = snes->type_name;
205: } else {
206: deft = SNESLS;
207: }
209: if (!SNESRegisterAllCalled) {SNESRegisterAll(PETSC_NULL);}
210: PetscOptionsList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
211: if (flg) {
212: SNESSetType(snes,type);
213: } else if (!snes->type_name) {
214: SNESSetType(snes,deft);
215: }
216: PetscOptionsName("-snes_view","Print detailed information on solver used","SNESView",0);
218: PetscOptionsReal("-snes_stol","Stop if step length less then","SNESSetTolerances",snes->xtol,&snes->xtol,0);
219: PetscOptionsReal("-snes_atol","Stop if function norm less then","SNESSetTolerances",snes->abstol,&snes->abstol,0);
221: PetscOptionsReal("-snes_rtol","Stop if decrease in function norm less then","SNESSetTolerances",snes->rtol,&snes->rtol,0);
222: PetscOptionsInt("-snes_max_it","Maximum iterations","SNESSetTolerances",snes->max_its,&snes->max_its,PETSC_NULL);
223: PetscOptionsInt("-snes_max_funcs","Maximum function evaluations","SNESSetTolerances",snes->max_funcs,&snes->max_funcs,PETSC_NULL);
224: PetscOptionsInt("-snes_max_fail","Maximum failures","SNESSetTolerances",snes->maxFailures,&snes->maxFailures,PETSC_NULL);
225: PetscOptionsName("-snes_converged_reason","Print reason for converged or diverged","SNESSolve",&flg);
226: if (flg) {
227: snes->printreason = PETSC_TRUE;
228: }
230: PetscOptionsTruth("-snes_ksp_ew_conv","Use Eisentat-Walker linear system convergence test","SNES_KSP_SetParametersEW",snes->ksp_ewconv,&snes->ksp_ewconv,PETSC_NULL);
232: PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNES_KSP_SetParametersEW",kctx->version,&kctx->version,0);
233: PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNES_KSP_SetParametersEW",kctx->rtol_0,&kctx->rtol_0,0);
234: PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNES_KSP_SetParametersEW",kctx->rtol_max,&kctx->rtol_max,0);
235: PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNES_KSP_SetParametersEW",kctx->gamma,&kctx->gamma,0);
236: PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNES_KSP_SetParametersEW",kctx->alpha,&kctx->alpha,0);
237: PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNES_KSP_SetParametersEW",kctx->alpha2,&kctx->alpha2,0);
238: PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNES_KSP_SetParametersEW",kctx->threshold,&kctx->threshold,0);
240: PetscOptionsName("-snes_no_convergence_test","Don't test for convergence","None",&flg);
241: if (flg) {snes->ops->converged = 0;}
242: PetscOptionsName("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",&flg);
243: if (flg) {SNESMonitorCancel(snes);}
245: PetscOptionsString("-snes_monitor","Monitor norm of function","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
246: if (flg) {
247: PetscViewerASCIIMonitorCreate(snes->comm,monfilename,0,&monviewer);
248: SNESMonitorSet(snes,SNESMonitorDefault,monviewer,(PetscErrorCode (*)(void*))PetscViewerASCIIMonitorDestroy);
249: }
251: PetscOptionsString("-snes_ratiomonitor","Monitor ratios of norms of function","SNESMonitorSetRatio","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
252: if (flg) {
253: PetscViewerASCIIMonitorCreate(snes->comm,monfilename,0,&monviewer);
254: SNESMonitorSetRatio(snes,monviewer);
255: }
257: PetscOptionsString("-snes_monitor_short","Monitor norm of function (fewer digits)","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
258: if (flg) {
259: PetscViewerASCIIMonitorCreate(snes->comm,monfilename,0,&monviewer);
260: SNESMonitorSet(snes,SNESMonitorDefaultShort,monviewer,(PetscErrorCode (*)(void*))PetscViewerASCIIMonitorDestroy);
261: }
263: PetscOptionsName("-snes_monitor_solution","Plot solution at each iteration","SNESMonitorSolution",&flg);
264: if (flg) {SNESMonitorSet(snes,SNESMonitorSolution,0,0);}
265: PetscOptionsName("-snes_monitor_solution_update","Plot correction at each iteration","SNESMonitorSolutionUpdate",&flg);
266: if (flg) {SNESMonitorSet(snes,SNESMonitorSolutionUpdate,0,0);}
267: PetscOptionsName("-snes_monitor_residual","Plot residual at each iteration","SNESMonitorResidual",&flg);
268: if (flg) {SNESMonitorSet(snes,SNESMonitorResidual,0,0);}
269: PetscOptionsName("-snes_monitor_draw","Plot function norm at each iteration","SNESMonitorLG",&flg);
270: if (flg) {SNESMonitorSet(snes,SNESMonitorLG,PETSC_NULL,PETSC_NULL);}
272: PetscOptionsName("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESDefaultComputeJacobian",&flg);
273: if (flg) {
274: SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESDefaultComputeJacobian,snes->funP);
275: PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
276: }
278: for(i = 0; i < numberofsetfromoptions; i++) {
279: (*othersetfromoptions[i])(snes);
280: }
282: if (snes->ops->setfromoptions) {
283: (*snes->ops->setfromoptions)(snes);
284: }
285: PetscOptionsEnd();
287: SNESGetKSP(snes,&ksp);
288: KSPSetFromOptions(ksp);
290: return(0);
291: }
296: /*@
297: SNESSetApplicationContext - Sets the optional user-defined context for
298: the nonlinear solvers.
300: Collective on SNES
302: Input Parameters:
303: + snes - the SNES context
304: - usrP - optional user context
306: Level: intermediate
308: .keywords: SNES, nonlinear, set, application, context
310: .seealso: SNESGetApplicationContext()
311: @*/
312: PetscErrorCode SNESSetApplicationContext(SNES snes,void *usrP)
313: {
316: snes->user = usrP;
317: return(0);
318: }
322: /*@C
323: SNESGetApplicationContext - Gets the user-defined context for the
324: nonlinear solvers.
326: Not Collective
328: Input Parameter:
329: . snes - SNES context
331: Output Parameter:
332: . usrP - user context
334: Level: intermediate
336: .keywords: SNES, nonlinear, get, application, context
338: .seealso: SNESSetApplicationContext()
339: @*/
340: PetscErrorCode SNESGetApplicationContext(SNES snes,void **usrP)
341: {
344: *usrP = snes->user;
345: return(0);
346: }
350: /*@
351: SNESGetIterationNumber - Gets the number of nonlinear iterations completed
352: at this time.
354: Not Collective
356: Input Parameter:
357: . snes - SNES context
359: Output Parameter:
360: . iter - iteration number
362: Notes:
363: For example, during the computation of iteration 2 this would return 1.
365: This is useful for using lagged Jacobians (where one does not recompute the
366: Jacobian at each SNES iteration). For example, the code
367: .vb
368: SNESGetIterationNumber(snes,&it);
369: if (!(it % 2)) {
370: [compute Jacobian here]
371: }
372: .ve
373: can be used in your ComputeJacobian() function to cause the Jacobian to be
374: recomputed every second SNES iteration.
376: Level: intermediate
378: .keywords: SNES, nonlinear, get, iteration, number,
380: .seealso: SNESGetFunctionNorm(), SNESGetNumberLinearIterations()
381: @*/
382: PetscErrorCode SNESGetIterationNumber(SNES snes,PetscInt* iter)
383: {
387: *iter = snes->iter;
388: return(0);
389: }
393: /*@
394: SNESGetFunctionNorm - Gets the norm of the current function that was set
395: with SNESSSetFunction().
397: Collective on SNES
399: Input Parameter:
400: . snes - SNES context
402: Output Parameter:
403: . fnorm - 2-norm of function
405: Level: intermediate
407: .keywords: SNES, nonlinear, get, function, norm
409: .seealso: SNESGetFunction(), SNESGetIterationNumber(), SNESGetNumberLinearIterations()
410: @*/
411: PetscErrorCode SNESGetFunctionNorm(SNES snes,PetscScalar *fnorm)
412: {
416: *fnorm = snes->norm;
417: return(0);
418: }
422: /*@
423: SNESGetNumberUnsuccessfulSteps - Gets the number of unsuccessful steps
424: attempted by the nonlinear solver.
426: Not Collective
428: Input Parameter:
429: . snes - SNES context
431: Output Parameter:
432: . nfails - number of unsuccessful steps attempted
434: Notes:
435: This counter is reset to zero for each successive call to SNESSolve().
437: Level: intermediate
439: .keywords: SNES, nonlinear, get, number, unsuccessful, steps
440: @*/
441: PetscErrorCode SNESGetNumberUnsuccessfulSteps(SNES snes,PetscInt* nfails)
442: {
446: *nfails = snes->numFailures;
447: return(0);
448: }
452: /*@
453: SNESSetMaximumUnsuccessfulSteps - Sets the maximum number of unsuccessful steps
454: attempted by the nonlinear solver before it gives up.
456: Not Collective
458: Input Parameters:
459: + snes - SNES context
460: - maxFails - maximum of unsuccessful steps
462: Level: intermediate
464: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps
465: @*/
466: PetscErrorCode SNESSetMaximumUnsuccessfulSteps(SNES snes, PetscInt maxFails)
467: {
470: snes->maxFailures = maxFails;
471: return(0);
472: }
476: /*@
477: SNESGetMaximumUnsuccessfulSteps - Gets the maximum number of unsuccessful steps
478: attempted by the nonlinear solver before it gives up.
480: Not Collective
482: Input Parameter:
483: . snes - SNES context
485: Output Parameter:
486: . maxFails - maximum of unsuccessful steps
488: Level: intermediate
490: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps
491: @*/
492: PetscErrorCode SNESGetMaximumUnsuccessfulSteps(SNES snes, PetscInt *maxFails)
493: {
497: *maxFails = snes->maxFailures;
498: return(0);
499: }
503: /*@
504: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
505: linear solvers.
507: Not Collective
509: Input Parameter:
510: . snes - SNES context
512: Output Parameter:
513: . nfails - number of failed solves
515: Notes:
516: This counter is reset to zero for each successive call to SNESSolve().
518: Level: intermediate
520: .keywords: SNES, nonlinear, get, number, unsuccessful, steps
521: @*/
522: PetscErrorCode SNESGetLinearSolveFailures(SNES snes,PetscInt* nfails)
523: {
527: *nfails = snes->numLinearSolveFailures;
528: return(0);
529: }
533: /*@
534: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
535: allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE
537: Collective on SNES
539: Input Parameters:
540: + snes - SNES context
541: - maxFails - maximum allowed linear solve failures
543: Level: intermediate
545: Notes: By default this is 1; that is SNES returns on the first failed linear solve
547: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps
549: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures()
550: @*/
551: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
552: {
555: snes->maxLinearSolveFailures = maxFails;
556: return(0);
557: }
561: /*@
562: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
563: are allowed before SNES terminates
565: Not Collective
567: Input Parameter:
568: . snes - SNES context
570: Output Parameter:
571: . maxFails - maximum of unsuccessful solves allowed
573: Level: intermediate
575: Notes: By default this is 1; that is SNES returns on the first failed linear solve
577: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps
579: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures()
580: @*/
581: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
582: {
586: *maxFails = snes->maxLinearSolveFailures;
587: return(0);
588: }
592: /*@
593: SNESGetNumberLinearIterations - Gets the total number of linear iterations
594: used by the nonlinear solver.
596: Not Collective
598: Input Parameter:
599: . snes - SNES context
601: Output Parameter:
602: . lits - number of linear iterations
604: Notes:
605: This counter is reset to zero for each successive call to SNESSolve().
607: Level: intermediate
609: .keywords: SNES, nonlinear, get, number, linear, iterations
611: .seealso: SNESGetIterationNumber(), SNESGetFunctionNorm()
612: @*/
613: PetscErrorCode SNESGetNumberLinearIterations(SNES snes,PetscInt* lits)
614: {
618: *lits = snes->linear_its;
619: return(0);
620: }
624: /*@
625: SNESGetKSP - Returns the KSP context for a SNES solver.
627: Not Collective, but if SNES object is parallel, then KSP object is parallel
629: Input Parameter:
630: . snes - the SNES context
632: Output Parameter:
633: . ksp - the KSP context
635: Notes:
636: The user can then directly manipulate the KSP context to set various
637: options, etc. Likewise, the user can then extract and manipulate the
638: PC contexts as well.
640: Level: beginner
642: .keywords: SNES, nonlinear, get, KSP, context
644: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
645: @*/
646: PetscErrorCode SNESGetKSP(SNES snes,KSP *ksp)
647: {
651: *ksp = snes->ksp;
652: return(0);
653: }
657: /*@
658: SNESSetKSP - Sets a KSP context for the SNES object to use
660: Not Collective, but the SNES and KSP objects must live on the same MPI_Comm
662: Input Parameters:
663: + snes - the SNES context
664: - ksp - the KSP context
666: Notes:
667: The SNES object already has its KSP object, you can obtain with SNESGetKSP()
668: so this routine is rarely needed.
670: The KSP object that is already in the SNES object has its reference count
671: decreased by one.
673: Level: developer
675: .keywords: SNES, nonlinear, get, KSP, context
677: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
678: @*/
679: PetscErrorCode SNESSetKSP(SNES snes,KSP ksp)
680: {
687: PetscObjectReference((PetscObject)ksp);
688: if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
689: snes->ksp = ksp;
690: return(0);
691: }
695: static PetscErrorCode SNESPublish_Petsc(PetscObject obj)
696: {
698: return(0);
699: }
701: /* -----------------------------------------------------------*/
704: /*@
705: SNESCreate - Creates a nonlinear solver context.
707: Collective on MPI_Comm
709: Input Parameters:
710: . comm - MPI communicator
712: Output Parameter:
713: . outsnes - the new SNES context
715: Options Database Keys:
716: + -snes_mf - Activates default matrix-free Jacobian-vector products,
717: and no preconditioning matrix
718: . -snes_mf_operator - Activates default matrix-free Jacobian-vector
719: products, and a user-provided preconditioning matrix
720: as set by SNESSetJacobian()
721: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
723: Level: beginner
725: .keywords: SNES, nonlinear, create, context
727: .seealso: SNESSolve(), SNESDestroy(), SNES
728: @*/
729: PetscErrorCode SNESCreate(MPI_Comm comm,SNES *outsnes)
730: {
731: PetscErrorCode ierr;
732: SNES snes;
733: SNES_KSP_EW_ConvCtx *kctx;
737: *outsnes = PETSC_NULL;
738: #ifndef PETSC_USE_DYNAMIC_LIBRARIES
739: SNESInitializePackage(PETSC_NULL);
740: #endif
742: PetscHeaderCreate(snes,_p_SNES,struct _SNESOps,SNES_COOKIE,0,"SNES",comm,SNESDestroy,SNESView);
743: snes->bops->publish = SNESPublish_Petsc;
744: snes->max_its = 50;
745: snes->max_funcs = 10000;
746: snes->norm = 0.0;
747: snes->rtol = 1.e-8;
748: snes->ttol = 0.0;
749: snes->abstol = 1.e-50;
750: snes->xtol = 1.e-8;
751: snes->deltatol = 1.e-12;
752: snes->nfuncs = 0;
753: snes->numFailures = 0;
754: snes->maxFailures = 1;
755: snes->linear_its = 0;
756: snes->numbermonitors = 0;
757: snes->data = 0;
758: snes->ops->view = 0;
759: snes->setupcalled = PETSC_FALSE;
760: snes->ksp_ewconv = PETSC_FALSE;
761: snes->vwork = 0;
762: snes->nwork = 0;
763: snes->conv_hist_len = 0;
764: snes->conv_hist_max = 0;
765: snes->conv_hist = PETSC_NULL;
766: snes->conv_hist_its = PETSC_NULL;
767: snes->conv_hist_reset = PETSC_TRUE;
768: snes->reason = SNES_CONVERGED_ITERATING;
770: snes->numLinearSolveFailures = 0;
771: snes->maxLinearSolveFailures = 1;
773: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
774: PetscNew(SNES_KSP_EW_ConvCtx,&kctx);
775: PetscLogObjectMemory(snes,sizeof(SNES_KSP_EW_ConvCtx));
776: snes->kspconvctx = (void*)kctx;
777: kctx->version = 2;
778: kctx->rtol_0 = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
779: this was too large for some test cases */
780: kctx->rtol_last = 0;
781: kctx->rtol_max = .9;
782: kctx->gamma = 1.0;
783: kctx->alpha2 = .5*(1.0 + sqrt(5.0));
784: kctx->alpha = kctx->alpha2;
785: kctx->threshold = .1;
786: kctx->lresid_last = 0;
787: kctx->norm_last = 0;
789: KSPCreate(comm,&snes->ksp);
790: PetscLogObjectParent(snes,snes->ksp);
792: *outsnes = snes;
793: PetscPublishAll(snes);
794: return(0);
795: }
799: /*@C
800: SNESSetFunction - Sets the function evaluation routine and function
801: vector for use by the SNES routines in solving systems of nonlinear
802: equations.
804: Collective on SNES
806: Input Parameters:
807: + snes - the SNES context
808: . r - vector to store function value
809: . func - function evaluation routine
810: - ctx - [optional] user-defined context for private data for the
811: function evaluation routine (may be PETSC_NULL)
813: Calling sequence of func:
814: $ func (SNES snes,Vec x,Vec f,void *ctx);
816: . f - function vector
817: - ctx - optional user-defined function context
819: Notes:
820: The Newton-like methods typically solve linear systems of the form
821: $ f'(x) x = -f(x),
822: where f'(x) denotes the Jacobian matrix and f(x) is the function.
824: Level: beginner
826: .keywords: SNES, nonlinear, set, function
828: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
829: @*/
830: PetscErrorCode SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*func)(SNES,Vec,Vec,void*),void *ctx)
831: {
837: snes->ops->computefunction = func;
838: snes->vec_func = snes->vec_func_always = r;
839: snes->funP = ctx;
840: return(0);
841: }
843: /* --------------------------------------------------------------- */
846: /*@C
847: SNESSetRhs - Sets the vector for solving F(x) = rhs. If rhs is not set
848: it assumes a zero right hand side.
850: Collective on SNES
852: Input Parameters:
853: + snes - the SNES context
854: - rhs - the right hand side vector or PETSC_NULL for a zero right hand side
856: Level: intermediate
858: .keywords: SNES, nonlinear, set, function, right hand side
860: .seealso: SNESGetRhs(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
861: @*/
862: PetscErrorCode SNESSetRhs(SNES snes,Vec rhs)
863: {
868: if (rhs) {
871: PetscObjectReference((PetscObject)rhs);
872: }
873: if (snes->afine) {
874: VecDestroy(snes->afine);
875: }
876: snes->afine = rhs;
877: return(0);
878: }
882: /*@C
883: SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
884: it assumes a zero right hand side.
886: Collective on SNES
888: Input Parameter:
889: . snes - the SNES context
891: Output Parameter:
892: . rhs - the right hand side vector or PETSC_NULL for a zero right hand side
894: Level: intermediate
896: .keywords: SNES, nonlinear, get, function, right hand side
898: .seealso: SNESSetRhs(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
899: @*/
900: PetscErrorCode SNESGetRhs(SNES snes,Vec *rhs)
901: {
905: *rhs = snes->afine;
906: return(0);
907: }
911: /*@
912: SNESComputeFunction - Calls the function that has been set with
913: SNESSetFunction().
915: Collective on SNES
917: Input Parameters:
918: + snes - the SNES context
919: - x - input vector
921: Output Parameter:
922: . y - function vector, as set by SNESSetFunction()
924: Notes:
925: SNESComputeFunction() is typically used within nonlinear solvers
926: implementations, so most users would not generally call this routine
927: themselves.
929: Level: developer
931: .keywords: SNES, nonlinear, compute, function
933: .seealso: SNESSetFunction(), SNESGetFunction()
934: @*/
935: PetscErrorCode SNESComputeFunction(SNES snes,Vec x,Vec y)
936: {
947: if (snes->ops->computefunction) {
948: PetscStackPush("SNES user function");
949: CHKMEMQ;
950: (*snes->ops->computefunction)(snes,x,y,snes->funP);
951: CHKMEMQ;
952: PetscStackPop;
953: if (PetscExceptionValue(ierr)) {
955: }
956:
957: } else if (snes->afine) {
958: MatMult(snes->jacobian, x, y);
959: } else {
960: SETERRQ(PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() before SNESComputeFunction(), likely called from SNESSolve().");
961: }
962: if (snes->afine) {
963: VecAXPY(y,-1.0,snes->afine);
964: }
965: snes->nfuncs++;
967: return(0);
968: }
972: /*@
973: SNESComputeJacobian - Computes the Jacobian matrix that has been
974: set with SNESSetJacobian().
976: Collective on SNES and Mat
978: Input Parameters:
979: + snes - the SNES context
980: - x - input vector
982: Output Parameters:
983: + A - Jacobian matrix
984: . B - optional preconditioning matrix
985: - flag - flag indicating matrix structure (one of, SAME_NONZERO_PATTERN,DIFFERENT_NONZERO_PATTERN,SAME_PRECONDITIONER)
987: Notes:
988: Most users should not need to explicitly call this routine, as it
989: is used internally within the nonlinear solvers.
991: See KSPSetOperators() for important information about setting the
992: flag parameter.
994: Level: developer
996: .keywords: SNES, compute, Jacobian, matrix
998: .seealso: SNESSetJacobian(), KSPSetOperators(), MatStructure
999: @*/
1000: PetscErrorCode SNESComputeJacobian(SNES snes,Vec X,Mat *A,Mat *B,MatStructure *flg)
1001: {
1009: if (!snes->ops->computejacobian) return(0);
1011: *flg = DIFFERENT_NONZERO_PATTERN;
1012: PetscStackPush("SNES user Jacobian function");
1013: CHKMEMQ;
1014: (*snes->ops->computejacobian)(snes,X,A,B,flg,snes->jacP);
1015: CHKMEMQ;
1016: PetscStackPop;
1018: /* make sure user returned a correct Jacobian and preconditioner */
1021: return(0);
1022: }
1026: /*@C
1027: SNESSetJacobian - Sets the function to compute Jacobian as well as the
1028: location to store the matrix.
1030: Collective on SNES and Mat
1032: Input Parameters:
1033: + snes - the SNES context
1034: . A - Jacobian matrix
1035: . B - preconditioner matrix (usually same as the Jacobian)
1036: . func - Jacobian evaluation routine
1037: - ctx - [optional] user-defined context for private data for the
1038: Jacobian evaluation routine (may be PETSC_NULL)
1040: Calling sequence of func:
1041: $ func (SNES snes,Vec x,Mat *A,Mat *B,int *flag,void *ctx);
1043: + x - input vector
1044: . A - Jacobian matrix
1045: . B - preconditioner matrix, usually the same as A
1046: . flag - flag indicating information about the preconditioner matrix
1047: structure (same as flag in KSPSetOperators()), one of SAME_NONZERO_PATTERN,DIFFERENT_NONZERO_PATTERN,SAME_PRECONDITIONER
1048: - ctx - [optional] user-defined Jacobian context
1050: Notes:
1051: See KSPSetOperators() for important information about setting the flag
1052: output parameter in the routine func(). Be sure to read this information!
1054: The routine func() takes Mat * as the matrix arguments rather than Mat.
1055: This allows the Jacobian evaluation routine to replace A and/or B with a
1056: completely new new matrix structure (not just different matrix elements)
1057: when appropriate, for instance, if the nonzero structure is changing
1058: throughout the global iterations.
1060: Level: beginner
1062: .keywords: SNES, nonlinear, set, Jacobian, matrix
1064: .seealso: KSPSetOperators(), SNESSetFunction(), MatSNESMFComputeJacobian(), SNESDefaultComputeJacobianColor(), MatStructure
1065: @*/
1066: PetscErrorCode SNESSetJacobian(SNES snes,Mat A,Mat B,PetscErrorCode (*func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void *ctx)
1067: {
1076: if (func) snes->ops->computejacobian = func;
1077: if (ctx) snes->jacP = ctx;
1078: if (A) {
1079: PetscObjectReference((PetscObject)A);
1080: if (snes->jacobian) {MatDestroy(snes->jacobian);}
1081: snes->jacobian = A;
1082: }
1083: if (B) {
1084: PetscObjectReference((PetscObject)B);
1085: if (snes->jacobian_pre) {MatDestroy(snes->jacobian_pre);}
1086: snes->jacobian_pre = B;
1087: }
1088: return(0);
1089: }
1093: /*@C
1094: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
1095: provided context for evaluating the Jacobian.
1097: Not Collective, but Mat object will be parallel if SNES object is
1099: Input Parameter:
1100: . snes - the nonlinear solver context
1102: Output Parameters:
1103: + A - location to stash Jacobian matrix (or PETSC_NULL)
1104: . B - location to stash preconditioner matrix (or PETSC_NULL)
1105: . func - location to put Jacobian function (or PETSC_NULL)
1106: - ctx - location to stash Jacobian ctx (or PETSC_NULL)
1108: Level: advanced
1110: .seealso: SNESSetJacobian(), SNESComputeJacobian()
1111: @*/
1112: PetscErrorCode SNESGetJacobian(SNES snes,Mat *A,Mat *B,PetscErrorCode (**func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void **ctx)
1113: {
1116: if (A) *A = snes->jacobian;
1117: if (B) *B = snes->jacobian_pre;
1118: if (func) *func = snes->ops->computejacobian;
1119: if (ctx) *ctx = snes->jacP;
1120: return(0);
1121: }
1123: /* ----- Routines to initialize and destroy a nonlinear solver ---- */
1124: EXTERN PetscErrorCode SNESDefaultMatrixFreeCreate2(SNES,Vec,Mat*);
1128: /*@
1129: SNESSetUp - Sets up the internal data structures for the later use
1130: of a nonlinear solver.
1132: Collective on SNES
1134: Input Parameters:
1135: . snes - the SNES context
1137: Notes:
1138: For basic use of the SNES solvers the user need not explicitly call
1139: SNESSetUp(), since these actions will automatically occur during
1140: the call to SNESSolve(). However, if one wishes to control this
1141: phase separately, SNESSetUp() should be called after SNESCreate()
1142: and optional routines of the form SNESSetXXX(), but before SNESSolve().
1144: Level: advanced
1146: .keywords: SNES, nonlinear, setup
1148: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
1149: @*/
1150: PetscErrorCode SNESSetUp(SNES snes)
1151: {
1153: PetscTruth flg, iseqtr;
1157: if (snes->setupcalled) return(0);
1159: PetscOptionsHasName(snes->prefix,"-snes_mf_operator",&flg);
1160: /*
1161: This version replaces the user provided Jacobian matrix with a
1162: matrix-free version but still employs the user-provided preconditioner matrix
1163: */
1164: if (flg) {
1165: Mat J;
1166: MatCreateSNESMF(snes,snes->vec_sol,&J);
1167: MatSNESMFSetFromOptions(J);
1168: PetscInfo(snes,"Setting default matrix-free operator routines\n");
1169: SNESSetJacobian(snes,J,0,0,0);
1170: MatDestroy(J);
1171: }
1173: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_SINGLE) && !defined(PETSC_USE_MAT_SINGLE) && !defined(PETSC_USE_LONG_DOUBLE) && !defined(PETSC_USE_INT)
1174: PetscOptionsHasName(snes->prefix,"-snes_mf_operator2",&flg);
1175: if (flg) {
1176: Mat J;
1177: SNESDefaultMatrixFreeCreate2(snes,snes->vec_sol,&J);
1178: SNESSetJacobian(snes,J,0,0,0);
1179: MatDestroy(J);
1180: }
1181: #endif
1183: PetscOptionsHasName(snes->prefix,"-snes_mf",&flg);
1184: /*
1185: This version replaces both the user-provided Jacobian and the user-
1186: provided preconditioner matrix with the default matrix free version.
1187: */
1188: if (flg) {
1189: Mat J;
1190: KSP ksp;
1191: PC pc;
1193: MatCreateSNESMF(snes,snes->vec_sol,&J);
1194: MatSNESMFSetFromOptions(J);
1195: PetscInfo(snes,"Setting default matrix-free operator and preconditioner routines;\nThat is no preconditioner is being used.\n");
1196: SNESSetJacobian(snes,J,J,MatSNESMFComputeJacobian,snes->funP);
1197: MatDestroy(J);
1199: /* force no preconditioner */
1200: SNESGetKSP(snes,&ksp);
1201: KSPGetPC(ksp,&pc);
1202: PetscTypeCompare((PetscObject)pc,PCSHELL,&flg);
1203: if (!flg) {
1204: PCSetType(pc,PCNONE);
1205: }
1206: }
1208: if (!snes->vec_func && !snes->afine) {
1209: SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Must call SNESSetFunction() first");
1210: }
1211: if (!snes->ops->computefunction && !snes->afine) {
1212: SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Must call SNESSetFunction() first");
1213: }
1214: if (!snes->jacobian) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Must call SNESSetJacobian() first \n or use -snes_mf option");
1215: if (snes->vec_func == snes->vec_sol) {
1216: SETERRQ(PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
1217: }
1219: /* Set the KSP stopping criterion to use the Eisenstat-Walker method */
1220: PetscTypeCompare((PetscObject)snes,SNESTR,&iseqtr);
1221: if (snes->ksp_ewconv && !iseqtr) {
1222: KSP ksp;
1223: SNESGetKSP(snes,&ksp);
1224: KSPSetConvergenceTest(ksp,SNES_KSP_EW_Converged_Private,snes);
1225: }
1226:
1227: if (!snes->type_name) {
1228: SNESSetType(snes,SNESLS);
1229: }
1230: if (snes->ops->setup) {
1231: (*snes->ops->setup)(snes);
1232: }
1233: snes->setupcalled = PETSC_TRUE;
1234: return(0);
1235: }
1239: /*@
1240: SNESDestroy - Destroys the nonlinear solver context that was created
1241: with SNESCreate().
1243: Collective on SNES
1245: Input Parameter:
1246: . snes - the SNES context
1248: Level: beginner
1250: .keywords: SNES, nonlinear, destroy
1252: .seealso: SNESCreate(), SNESSolve()
1253: @*/
1254: PetscErrorCode SNESDestroy(SNES snes)
1255: {
1260: if (--snes->refct > 0) return(0);
1262: /* if memory was published with AMS then destroy it */
1263: PetscObjectDepublish(snes);
1265: if (snes->ops->destroy) {(*(snes)->ops->destroy)(snes);}
1266: PetscFree(snes->kspconvctx);
1267: if (snes->jacobian) {MatDestroy(snes->jacobian);}
1268: if (snes->jacobian_pre) {MatDestroy(snes->jacobian_pre);}
1269: if (snes->afine) {VecDestroy(snes->afine);}
1270: KSPDestroy(snes->ksp);
1271: if (snes->vwork) {VecDestroyVecs(snes->vwork,snes->nvwork);}
1272: SNESMonitorCancel(snes);
1273: PetscHeaderDestroy(snes);
1274: return(0);
1275: }
1277: /* ----------- Routines to set solver parameters ---------- */
1281: /*@
1282: SNESSetTolerances - Sets various parameters used in convergence tests.
1284: Collective on SNES
1286: Input Parameters:
1287: + snes - the SNES context
1288: . abstol - absolute convergence tolerance
1289: . rtol - relative convergence tolerance
1290: . stol - convergence tolerance in terms of the norm
1291: of the change in the solution between steps
1292: . maxit - maximum number of iterations
1293: - maxf - maximum number of function evaluations
1295: Options Database Keys:
1296: + -snes_atol <abstol> - Sets abstol
1297: . -snes_rtol <rtol> - Sets rtol
1298: . -snes_stol <stol> - Sets stol
1299: . -snes_max_it <maxit> - Sets maxit
1300: - -snes_max_funcs <maxf> - Sets maxf
1302: Notes:
1303: The default maximum number of iterations is 50.
1304: The default maximum number of function evaluations is 1000.
1306: Level: intermediate
1308: .keywords: SNES, nonlinear, set, convergence, tolerances
1310: .seealso: SNESSetTrustRegionTolerance()
1311: @*/
1312: PetscErrorCode SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
1313: {
1316: if (abstol != PETSC_DEFAULT) snes->abstol = abstol;
1317: if (rtol != PETSC_DEFAULT) snes->rtol = rtol;
1318: if (stol != PETSC_DEFAULT) snes->xtol = stol;
1319: if (maxit != PETSC_DEFAULT) snes->max_its = maxit;
1320: if (maxf != PETSC_DEFAULT) snes->max_funcs = maxf;
1321: return(0);
1322: }
1326: /*@
1327: SNESGetTolerances - Gets various parameters used in convergence tests.
1329: Not Collective
1331: Input Parameters:
1332: + snes - the SNES context
1333: . abstol - absolute convergence tolerance
1334: . rtol - relative convergence tolerance
1335: . stol - convergence tolerance in terms of the norm
1336: of the change in the solution between steps
1337: . maxit - maximum number of iterations
1338: - maxf - maximum number of function evaluations
1340: Notes:
1341: The user can specify PETSC_NULL for any parameter that is not needed.
1343: Level: intermediate
1345: .keywords: SNES, nonlinear, get, convergence, tolerances
1347: .seealso: SNESSetTolerances()
1348: @*/
1349: PetscErrorCode SNESGetTolerances(SNES snes,PetscReal *abstol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
1350: {
1353: if (abstol) *abstol = snes->abstol;
1354: if (rtol) *rtol = snes->rtol;
1355: if (stol) *stol = snes->xtol;
1356: if (maxit) *maxit = snes->max_its;
1357: if (maxf) *maxf = snes->max_funcs;
1358: return(0);
1359: }
1363: /*@
1364: SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.
1366: Collective on SNES
1368: Input Parameters:
1369: + snes - the SNES context
1370: - tol - tolerance
1371:
1372: Options Database Key:
1373: . -snes_trtol <tol> - Sets tol
1375: Level: intermediate
1377: .keywords: SNES, nonlinear, set, trust region, tolerance
1379: .seealso: SNESSetTolerances()
1380: @*/
1381: PetscErrorCode SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
1382: {
1385: snes->deltatol = tol;
1386: return(0);
1387: }
1389: /*
1390: Duplicate the lg monitors for SNES from KSP; for some reason with
1391: dynamic libraries things don't work under Sun4 if we just use
1392: macros instead of functions
1393: */
1396: PetscErrorCode SNESMonitorLG(SNES snes,PetscInt it,PetscReal norm,void *ctx)
1397: {
1402: KSPMonitorLG((KSP)snes,it,norm,ctx);
1403: return(0);
1404: }
1408: PetscErrorCode SNESMonitorLGCreate(const char host[],const char label[],int x,int y,int m,int n,PetscDrawLG *draw)
1409: {
1413: KSPMonitorLGCreate(host,label,x,y,m,n,draw);
1414: return(0);
1415: }
1419: PetscErrorCode SNESMonitorLGDestroy(PetscDrawLG draw)
1420: {
1424: KSPMonitorLGDestroy(draw);
1425: return(0);
1426: }
1428: /* ------------ Routines to set performance monitoring options ----------- */
1432: /*@C
1433: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
1434: iteration of the nonlinear solver to display the iteration's
1435: progress.
1437: Collective on SNES
1439: Input Parameters:
1440: + snes - the SNES context
1441: . func - monitoring routine
1442: . mctx - [optional] user-defined context for private data for the
1443: monitor routine (use PETSC_NULL if no context is desired)
1444: - monitordestroy - [optional] routine that frees monitor context
1445: (may be PETSC_NULL)
1447: Calling sequence of func:
1448: $ int func(SNES snes,PetscInt its, PetscReal norm,void *mctx)
1450: + snes - the SNES context
1451: . its - iteration number
1452: . norm - 2-norm function value (may be estimated)
1453: - mctx - [optional] monitoring context
1455: Options Database Keys:
1456: + -snes_monitor - sets SNESMonitorDefault()
1457: . -snes_monitor_draw - sets line graph monitor,
1458: uses SNESMonitorLGCreate()
1459: _ -snes_monitor_cancel - cancels all monitors that have
1460: been hardwired into a code by
1461: calls to SNESMonitorSet(), but
1462: does not cancel those set via
1463: the options database.
1465: Notes:
1466: Several different monitoring routines may be set by calling
1467: SNESMonitorSet() multiple times; all will be called in the
1468: order in which they were set.
1470: Level: intermediate
1472: .keywords: SNES, nonlinear, set, monitor
1474: .seealso: SNESMonitorDefault(), SNESMonitorCancel()
1475: @*/
1476: PetscErrorCode SNESMonitorSet(SNES snes,PetscErrorCode (*func)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void*))
1477: {
1480: if (snes->numbermonitors >= MAXSNESMONITORS) {
1481: SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
1482: }
1483: snes->monitor[snes->numbermonitors] = func;
1484: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
1485: snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
1486: return(0);
1487: }
1491: /*@C
1492: SNESMonitorCancel - Clears all the monitor functions for a SNES object.
1494: Collective on SNES
1496: Input Parameters:
1497: . snes - the SNES context
1499: Options Database Key:
1500: . -snes_monitor_cancel - cancels all monitors that have been hardwired
1501: into a code by calls to SNESMonitorSet(), but does not cancel those
1502: set via the options database
1504: Notes:
1505: There is no way to clear one specific monitor from a SNES object.
1507: Level: intermediate
1509: .keywords: SNES, nonlinear, set, monitor
1511: .seealso: SNESMonitorDefault(), SNESMonitorSet()
1512: @*/
1513: PetscErrorCode SNESMonitorCancel(SNES snes)
1514: {
1516: PetscInt i;
1520: for (i=0; i<snes->numbermonitors; i++) {
1521: if (snes->monitordestroy[i]) {
1522: (*snes->monitordestroy[i])(snes->monitorcontext[i]);
1523: }
1524: }
1525: snes->numbermonitors = 0;
1526: return(0);
1527: }
1531: /*@C
1532: SNESSetConvergenceTest - Sets the function that is to be used
1533: to test for convergence of the nonlinear iterative solution.
1535: Collective on SNES
1537: Input Parameters:
1538: + snes - the SNES context
1539: . func - routine to test for convergence
1540: - cctx - [optional] context for private data for the convergence routine
1541: (may be PETSC_NULL)
1543: Calling sequence of func:
1544: $ PetscErrorCode func (SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)
1546: + snes - the SNES context
1547: . it - current iteration (0 is the first and is before any Newton step)
1548: . cctx - [optional] convergence context
1549: . reason - reason for convergence/divergence
1550: . xnorm - 2-norm of current iterate
1551: . gnorm - 2-norm of current step
1552: - f - 2-norm of function
1554: Level: advanced
1556: .keywords: SNES, nonlinear, set, convergence, test
1558: .seealso: SNESConverged_LS(), SNESConverged_TR()
1559: @*/
1560: PetscErrorCode SNESSetConvergenceTest(SNES snes,PetscErrorCode (*func)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx)
1561: {
1564: (snes)->ops->converged = func;
1565: (snes)->cnvP = cctx;
1566: return(0);
1567: }
1571: /*@
1572: SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.
1574: Not Collective
1576: Input Parameter:
1577: . snes - the SNES context
1579: Output Parameter:
1580: . reason - negative value indicates diverged, positive value converged, see petscsnes.h or the
1581: manual pages for the individual convergence tests for complete lists
1583: Level: intermediate
1585: Notes: Can only be called after the call the SNESSolve() is complete.
1587: .keywords: SNES, nonlinear, set, convergence, test
1589: .seealso: SNESSetConvergenceTest(), SNESConverged_LS(), SNESConverged_TR(), SNESConvergedReason
1590: @*/
1591: PetscErrorCode SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
1592: {
1596: *reason = snes->reason;
1597: return(0);
1598: }
1602: /*@
1603: SNESSetConvergenceHistory - Sets the array used to hold the convergence history.
1605: Collective on SNES
1607: Input Parameters:
1608: + snes - iterative context obtained from SNESCreate()
1609: . a - array to hold history
1610: . its - integer array holds the number of linear iterations for each solve.
1611: . na - size of a and its
1612: - reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
1613: else it continues storing new values for new nonlinear solves after the old ones
1615: Notes:
1616: If set, this array will contain the function norms computed
1617: at each step.
1619: This routine is useful, e.g., when running a code for purposes
1620: of accurate performance monitoring, when no I/O should be done
1621: during the section of code that is being timed.
1623: Level: intermediate
1625: .keywords: SNES, set, convergence, history
1627: .seealso: SNESGetConvergenceHistory()
1629: @*/
1630: PetscErrorCode SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt *its,PetscInt na,PetscTruth reset)
1631: {
1635: snes->conv_hist = a;
1636: snes->conv_hist_its = its;
1637: snes->conv_hist_max = na;
1638: snes->conv_hist_reset = reset;
1639: return(0);
1640: }
1644: /*@C
1645: SNESGetConvergenceHistory - Gets the array used to hold the convergence history.
1647: Collective on SNES
1649: Input Parameter:
1650: . snes - iterative context obtained from SNESCreate()
1652: Output Parameters:
1653: . a - array to hold history
1654: . its - integer array holds the number of linear iterations (or
1655: negative if not converged) for each solve.
1656: - na - size of a and its
1658: Notes:
1659: The calling sequence for this routine in Fortran is
1660: $ call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)
1662: This routine is useful, e.g., when running a code for purposes
1663: of accurate performance monitoring, when no I/O should be done
1664: during the section of code that is being timed.
1666: Level: intermediate
1668: .keywords: SNES, get, convergence, history
1670: .seealso: SNESSetConvergencHistory()
1672: @*/
1673: PetscErrorCode SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
1674: {
1677: if (a) *a = snes->conv_hist;
1678: if (its) *its = snes->conv_hist_its;
1679: if (na) *na = snes->conv_hist_len;
1680: return(0);
1681: }
1685: /*@C
1686: SNESSetUpdate - Sets the general-purpose update function called
1687: at the beginning o every iteration of the nonlinear solve. Specifically
1688: it is called just before the Jacobian is "evaluated".
1690: Collective on SNES
1692: Input Parameters:
1693: . snes - The nonlinear solver context
1694: . func - The function
1696: Calling sequence of func:
1697: . func (SNES snes, PetscInt step);
1699: . step - The current step of the iteration
1701: Level: intermediate
1703: .keywords: SNES, update
1705: .seealso SNESDefaultUpdate(), SNESSetRhsBC(), SNESSetSolutionBC()
1706: @*/
1707: PetscErrorCode SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
1708: {
1711: snes->ops->update = func;
1712: return(0);
1713: }
1717: /*@
1718: SNESDefaultUpdate - The default update function which does nothing.
1720: Not collective
1722: Input Parameters:
1723: . snes - The nonlinear solver context
1724: . step - The current step of the iteration
1726: Level: intermediate
1728: .keywords: SNES, update
1729: .seealso SNESSetUpdate(), SNESDefaultRhsBC(), SNESDefaultShortolutionBC()
1730: @*/
1731: PetscErrorCode SNESDefaultUpdate(SNES snes, PetscInt step)
1732: {
1734: return(0);
1735: }
1739: /*
1740: SNESScaleStep_Private - Scales a step so that its length is less than the
1741: positive parameter delta.
1743: Input Parameters:
1744: + snes - the SNES context
1745: . y - approximate solution of linear system
1746: . fnorm - 2-norm of current function
1747: - delta - trust region size
1749: Output Parameters:
1750: + gpnorm - predicted function norm at the new point, assuming local
1751: linearization. The value is zero if the step lies within the trust
1752: region, and exceeds zero otherwise.
1753: - ynorm - 2-norm of the step
1755: Note:
1756: For non-trust region methods such as SNESLS, the parameter delta
1757: is set to be the maximum allowable step size.
1759: .keywords: SNES, nonlinear, scale, step
1760: */
1761: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
1762: {
1763: PetscReal nrm;
1764: PetscScalar cnorm;
1772: VecNorm(y,NORM_2,&nrm);
1773: if (nrm > *delta) {
1774: nrm = *delta/nrm;
1775: *gpnorm = (1.0 - nrm)*(*fnorm);
1776: cnorm = nrm;
1777: VecScale(y,cnorm);
1778: *ynorm = *delta;
1779: } else {
1780: *gpnorm = 0.0;
1781: *ynorm = nrm;
1782: }
1783: return(0);
1784: }
1788: /*@C
1789: SNESSolve - Solves a nonlinear system F(x) = b.
1790: Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().
1792: Collective on SNES
1794: Input Parameters:
1795: + snes - the SNES context
1796: . b - the constant part of the equation, or PETSC_NULL to use zero.
1797: - x - the solution vector, or PETSC_NULL if it was set with SNESSetSolution()
1799: Notes:
1800: The user should initialize the vector,x, with the initial guess
1801: for the nonlinear solve prior to calling SNESSolve. In particular,
1802: to employ an initial guess of zero, the user should explicitly set
1803: this vector to zero by calling VecSet().
1805: Level: beginner
1807: .keywords: SNES, nonlinear, solve
1809: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetRhs(), SNESSetSolution()
1810: @*/
1811: PetscErrorCode SNESSolve(SNES snes,Vec b,Vec x)
1812: {
1814: PetscTruth flg;
1815: char filename[PETSC_MAX_PATH_LEN];
1816: PetscViewer viewer;
1820: if (!snes->ops->solve) SETERRQ(PETSC_ERR_ORDER,"SNESSetType() or SNESSetFromOptions() must be called before SNESSolve()");
1822: if (b) {
1823: SNESSetRhs(snes, b);
1824: if (!snes->vec_func) {
1825: Vec r;
1827: VecDuplicate(b, &r);
1828: SNESSetFunction(snes, r, PETSC_NULL, PETSC_NULL);
1829: }
1830: }
1831: if (x) {
1834: } else {
1835: SNESGetSolution(snes, &x);
1836: if (!x) {
1837: VecDuplicate(snes->vec_func_always, &x);
1838: }
1839: }
1840: snes->vec_sol = snes->vec_sol_always = x;
1841: if (!snes->setupcalled) {
1842: SNESSetUp(snes);
1843: }
1844: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
1846: snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;
1848: PetscExceptionTry1((*(snes)->ops->solve)(snes),PETSC_ERR_ARG_DOMAIN);
1849: if (PetscExceptionValue(ierr)) {
1850: /* this means that a caller above me has also tryed this exception so I don't handle it here, pass it up */
1852: } else if (PetscExceptionCaught(ierr,PETSC_ERR_ARG_DOMAIN)) {
1853: /* translate exception into SNES not converged reason */
1854: snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
1855: 0;
1856: }
1857:
1860: PetscOptionsGetString(snes->prefix,"-snes_view",filename,PETSC_MAX_PATH_LEN,&flg);
1861: if (flg && !PetscPreLoadingOn) {
1862: PetscViewerASCIIOpen(snes->comm,filename,&viewer);
1863: SNESView(snes,viewer);
1864: PetscViewerDestroy(viewer);
1865: }
1867: PetscOptionsHasName(snes->prefix,"-snes_test_local_min",&flg);
1868: if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
1869: if (snes->printreason) {
1870: if (snes->reason > 0) {
1871: PetscPrintf(snes->comm,"Nonlinear solve converged due to %s\n",SNESConvergedReasons[snes->reason]);
1872: } else {
1873: PetscPrintf(snes->comm,"Nonlinear solve did not converge due to %s\n",SNESConvergedReasons[snes->reason]);
1874: }
1875: }
1877: return(0);
1878: }
1880: /* --------- Internal routines for SNES Package --------- */
1884: /*@C
1885: SNESSetType - Sets the method for the nonlinear solver.
1887: Collective on SNES
1889: Input Parameters:
1890: + snes - the SNES context
1891: - type - a known method
1893: Options Database Key:
1894: . -snes_type <type> - Sets the method; use -help for a list
1895: of available methods (for instance, ls or tr)
1897: Notes:
1898: See "petsc/include/petscsnes.h" for available methods (for instance)
1899: + SNESLS - Newton's method with line search
1900: (systems of nonlinear equations)
1901: . SNESTR - Newton's method with trust region
1902: (systems of nonlinear equations)
1904: Normally, it is best to use the SNESSetFromOptions() command and then
1905: set the SNES solver type from the options database rather than by using
1906: this routine. Using the options database provides the user with
1907: maximum flexibility in evaluating the many nonlinear solvers.
1908: The SNESSetType() routine is provided for those situations where it
1909: is necessary to set the nonlinear solver independently of the command
1910: line or options database. This might be the case, for example, when
1911: the choice of solver changes during the execution of the program,
1912: and the user's application is taking responsibility for choosing the
1913: appropriate method.
1915: Level: intermediate
1917: .keywords: SNES, set, type
1919: .seealso: SNESType, SNESCreate()
1921: @*/
1922: PetscErrorCode SNESSetType(SNES snes,SNESType type)
1923: {
1924: PetscErrorCode ierr,(*r)(SNES);
1925: PetscTruth match;
1931: PetscTypeCompare((PetscObject)snes,type,&match);
1932: if (match) return(0);
1934: if (snes->setupcalled) {
1935: snes->setupcalled = PETSC_FALSE;
1936: (*(snes)->ops->destroy)(snes);
1937: snes->data = 0;
1938: }
1940: /* Get the function pointers for the iterative method requested */
1941: if (!SNESRegisterAllCalled) {SNESRegisterAll(PETSC_NULL);}
1942: PetscFListFind(snes->comm,SNESList,type,(void (**)(void)) &r);
1943: if (!r) SETERRQ1(PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
1944: PetscFree(snes->data);
1945: snes->data = 0;
1946: (*r)(snes);
1947: PetscObjectChangeTypeName((PetscObject)snes,type);
1948: return(0);
1949: }
1952: /* --------------------------------------------------------------------- */
1955: /*@
1956: SNESRegisterDestroy - Frees the list of nonlinear solvers that were
1957: registered by SNESRegisterDynamic().
1959: Not Collective
1961: Level: advanced
1963: .keywords: SNES, nonlinear, register, destroy
1965: .seealso: SNESRegisterAll(), SNESRegisterAll()
1966: @*/
1967: PetscErrorCode SNESRegisterDestroy(void)
1968: {
1972: if (SNESList) {
1973: PetscFListDestroy(&SNESList);
1974: SNESList = 0;
1975: }
1976: SNESRegisterAllCalled = PETSC_FALSE;
1977: return(0);
1978: }
1982: /*@C
1983: SNESGetType - Gets the SNES method type and name (as a string).
1985: Not Collective
1987: Input Parameter:
1988: . snes - nonlinear solver context
1990: Output Parameter:
1991: . type - SNES method (a character string)
1993: Level: intermediate
1995: .keywords: SNES, nonlinear, get, type, name
1996: @*/
1997: PetscErrorCode SNESGetType(SNES snes,SNESType *type)
1998: {
2002: *type = snes->type_name;
2003: return(0);
2004: }
2008: /*@
2009: SNESGetSolution - Returns the vector where the approximate solution is
2010: stored.
2012: Not Collective, but Vec is parallel if SNES is parallel
2014: Input Parameter:
2015: . snes - the SNES context
2017: Output Parameter:
2018: . x - the solution
2020: Level: intermediate
2022: .keywords: SNES, nonlinear, get, solution
2024: .seealso: SNESSetSolution(), SNESGetFunction(), SNESGetSolutionUpdate()
2025: @*/
2026: PetscErrorCode SNESGetSolution(SNES snes,Vec *x)
2027: {
2031: *x = snes->vec_sol_always;
2032: return(0);
2033: }
2037: /*@
2038: SNESSetSolution - Sets the vector where the approximate solution is stored.
2040: Not Collective, but Vec is parallel if SNES is parallel
2042: Input Parameters:
2043: + snes - the SNES context
2044: - x - the solution
2046: Output Parameter:
2048: Level: intermediate
2050: Notes: this is not normally used, rather one simply calls SNESSolve() with
2051: the appropriate solution vector.
2053: .keywords: SNES, nonlinear, set, solution
2055: .seealso: SNESGetSolution(), SNESGetFunction(), SNESGetSolutionUpdate()
2056: @*/
2057: PetscErrorCode SNESSetSolution(SNES snes,Vec x)
2058: {
2063: snes->vec_sol_always = x;
2064: return(0);
2065: }
2069: /*@
2070: SNESGetSolutionUpdate - Returns the vector where the solution update is
2071: stored.
2073: Not Collective, but Vec is parallel if SNES is parallel
2075: Input Parameter:
2076: . snes - the SNES context
2078: Output Parameter:
2079: . x - the solution update
2081: Level: advanced
2083: .keywords: SNES, nonlinear, get, solution, update
2085: .seealso: SNESGetSolution(), SNESGetFunction
2086: @*/
2087: PetscErrorCode SNESGetSolutionUpdate(SNES snes,Vec *x)
2088: {
2092: *x = snes->vec_sol_update_always;
2093: return(0);
2094: }
2098: /*@C
2099: SNESGetFunction - Returns the vector where the function is stored.
2101: Not Collective, but Vec is parallel if SNES is parallel
2103: Input Parameter:
2104: . snes - the SNES context
2106: Output Parameter:
2107: + r - the function (or PETSC_NULL)
2108: . func - the function (or PETSC_NULL)
2109: - ctx - the function context (or PETSC_NULL)
2111: Level: advanced
2113: .keywords: SNES, nonlinear, get, function
2115: .seealso: SNESSetFunction(), SNESGetSolution()
2116: @*/
2117: PetscErrorCode SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**func)(SNES,Vec,Vec,void*),void **ctx)
2118: {
2121: if (r) *r = snes->vec_func_always;
2122: if (func) *func = snes->ops->computefunction;
2123: if (ctx) *ctx = snes->funP;
2124: return(0);
2125: }
2129: /*@C
2130: SNESSetOptionsPrefix - Sets the prefix used for searching for all
2131: SNES options in the database.
2133: Collective on SNES
2135: Input Parameter:
2136: + snes - the SNES context
2137: - prefix - the prefix to prepend to all option names
2139: Notes:
2140: A hyphen (-) must NOT be given at the beginning of the prefix name.
2141: The first character of all runtime options is AUTOMATICALLY the hyphen.
2143: Level: advanced
2145: .keywords: SNES, set, options, prefix, database
2147: .seealso: SNESSetFromOptions()
2148: @*/
2149: PetscErrorCode SNESSetOptionsPrefix(SNES snes,const char prefix[])
2150: {
2155: PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
2156: KSPSetOptionsPrefix(snes->ksp,prefix);
2157: return(0);
2158: }
2162: /*@C
2163: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
2164: SNES options in the database.
2166: Collective on SNES
2168: Input Parameters:
2169: + snes - the SNES context
2170: - prefix - the prefix to prepend to all option names
2172: Notes:
2173: A hyphen (-) must NOT be given at the beginning of the prefix name.
2174: The first character of all runtime options is AUTOMATICALLY the hyphen.
2176: Level: advanced
2178: .keywords: SNES, append, options, prefix, database
2180: .seealso: SNESGetOptionsPrefix()
2181: @*/
2182: PetscErrorCode SNESAppendOptionsPrefix(SNES snes,const char prefix[])
2183: {
2185:
2188: PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
2189: KSPAppendOptionsPrefix(snes->ksp,prefix);
2190: return(0);
2191: }
2195: /*@C
2196: SNESGetOptionsPrefix - Sets the prefix used for searching for all
2197: SNES options in the database.
2199: Not Collective
2201: Input Parameter:
2202: . snes - the SNES context
2204: Output Parameter:
2205: . prefix - pointer to the prefix string used
2207: Notes: On the fortran side, the user should pass in a string 'prifix' of
2208: sufficient length to hold the prefix.
2210: Level: advanced
2212: .keywords: SNES, get, options, prefix, database
2214: .seealso: SNESAppendOptionsPrefix()
2215: @*/
2216: PetscErrorCode SNESGetOptionsPrefix(SNES snes,const char *prefix[])
2217: {
2222: PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
2223: return(0);
2224: }
2229: /*@C
2230: SNESRegister - See SNESRegisterDynamic()
2232: Level: advanced
2233: @*/
2234: PetscErrorCode SNESRegister(const char sname[],const char path[],const char name[],PetscErrorCode (*function)(SNES))
2235: {
2236: char fullname[PETSC_MAX_PATH_LEN];
2240: PetscFListConcat(path,name,fullname);
2241: PetscFListAdd(&SNESList,sname,fullname,(void (*)(void))function);
2242: return(0);
2243: }
2247: PetscErrorCode SNESTestLocalMin(SNES snes)
2248: {
2250: PetscInt N,i,j;
2251: Vec u,uh,fh;
2252: PetscScalar value;
2253: PetscReal norm;
2256: SNESGetSolution(snes,&u);
2257: VecDuplicate(u,&uh);
2258: VecDuplicate(u,&fh);
2260: /* currently only works for sequential */
2261: PetscPrintf(PETSC_COMM_WORLD,"Testing FormFunction() for local min\n");
2262: VecGetSize(u,&N);
2263: for (i=0; i<N; i++) {
2264: VecCopy(u,uh);
2265: PetscPrintf(PETSC_COMM_WORLD,"i = %D\n",i);
2266: for (j=-10; j<11; j++) {
2267: value = PetscSign(j)*exp(PetscAbs(j)-10.0);
2268: VecSetValue(uh,i,value,ADD_VALUES);
2269: SNESComputeFunction(snes,uh,fh);
2270: VecNorm(fh,NORM_2,&norm);
2271: PetscPrintf(PETSC_COMM_WORLD," j norm %D %18.16e\n",j,norm);
2272: value = -value;
2273: VecSetValue(uh,i,value,ADD_VALUES);
2274: }
2275: }
2276: VecDestroy(uh);
2277: VecDestroy(fh);
2278: return(0);
2279: }