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: SNESKSPEW *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 = (SNESKSPEW *)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 - 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: SNESKSPEW *kctx = (SNESKSPEW *)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","Use Eisentat-Walker linear system convergence test","SNESKSPSetUseEW",snes->ksp_ewconv,&snes->ksp_ewconv,PETSC_NULL);
232: PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,0);
233: PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,0);
234: PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,0);
235: PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,0);
236: PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,0);
237: PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,0);
238: PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",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(), SNESGetLinearSolveIterations()
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(), SNESGetLinearSolveIterations()
410: @*/
411: PetscErrorCode SNESGetFunctionNorm(SNES snes,PetscReal *fnorm)
412: {
416: *fnorm = snes->norm;
417: return(0);
418: }
422: /*@
423: SNESGetNonlinearStepFailures - 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 SNESGetNonlinearStepFailures(SNES snes,PetscInt* nfails)
442: {
446: *nfails = snes->numFailures;
447: return(0);
448: }
452: /*@
453: SNESSetMaxNonlinearStepFailures - 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 SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
467: {
470: snes->maxFailures = maxFails;
471: return(0);
472: }
476: /*@
477: SNESGetMaxNonlinearStepFailures - 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 SNESGetMaxNonlinearStepFailures(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: SNESGetLinearSolveIterations - 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 SNESGetLinearSolveIterations(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: SNESKSPEW *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->setupcalled = PETSC_FALSE;
759: snes->ksp_ewconv = PETSC_FALSE;
760: snes->vwork = 0;
761: snes->nwork = 0;
762: snes->conv_hist_len = 0;
763: snes->conv_hist_max = 0;
764: snes->conv_hist = PETSC_NULL;
765: snes->conv_hist_its = PETSC_NULL;
766: snes->conv_hist_reset = PETSC_TRUE;
767: snes->reason = SNES_CONVERGED_ITERATING;
769: snes->numLinearSolveFailures = 0;
770: snes->maxLinearSolveFailures = 1;
772: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
773: PetscNew(SNESKSPEW,&kctx);
774: PetscLogObjectMemory(snes,sizeof(SNESKSPEW));
775: snes->kspconvctx = (void*)kctx;
776: kctx->version = 2;
777: kctx->rtol_0 = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
778: this was too large for some test cases */
779: kctx->rtol_last = 0;
780: kctx->rtol_max = .9;
781: kctx->gamma = 1.0;
782: kctx->alpha = .5*(1.0 + sqrt(5.0));
783: kctx->alpha2 = kctx->alpha;
784: kctx->threshold = .1;
785: kctx->lresid_last = 0;
786: kctx->norm_last = 0;
788: KSPCreate(comm,&snes->ksp);
789: PetscLogObjectParent(snes,snes->ksp);
791: *outsnes = snes;
792: PetscPublishAll(snes);
793: return(0);
794: }
798: /*@C
799: SNESSetFunction - Sets the function evaluation routine and function
800: vector for use by the SNES routines in solving systems of nonlinear
801: equations.
803: Collective on SNES
805: Input Parameters:
806: + snes - the SNES context
807: . r - vector to store function value
808: . func - function evaluation routine
809: - ctx - [optional] user-defined context for private data for the
810: function evaluation routine (may be PETSC_NULL)
812: Calling sequence of func:
813: $ func (SNES snes,Vec x,Vec f,void *ctx);
815: . f - function vector
816: - ctx - optional user-defined function context
818: Notes:
819: The Newton-like methods typically solve linear systems of the form
820: $ f'(x) x = -f(x),
821: where f'(x) denotes the Jacobian matrix and f(x) is the function.
823: Level: beginner
825: .keywords: SNES, nonlinear, set, function
827: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
828: @*/
829: PetscErrorCode SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*func)(SNES,Vec,Vec,void*),void *ctx)
830: {
836: snes->ops->computefunction = func;
837: snes->vec_func = snes->vec_func_always = r;
838: snes->funP = ctx;
839: return(0);
840: }
842: /* --------------------------------------------------------------- */
845: /*@C
846: SNESSetRhs - Sets the vector for solving F(x) = rhs. If rhs is not set
847: it assumes a zero right hand side.
849: Collective on SNES
851: Input Parameters:
852: + snes - the SNES context
853: - rhs - the right hand side vector or PETSC_NULL for a zero right hand side
855: Level: intermediate
857: .keywords: SNES, nonlinear, set, function, right hand side
859: .seealso: SNESGetRhs(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
860: @*/
861: PetscErrorCode SNESSetRhs(SNES snes,Vec rhs)
862: {
867: if (rhs) {
870: PetscObjectReference((PetscObject)rhs);
871: }
872: if (snes->afine) {
873: VecDestroy(snes->afine);
874: }
875: snes->afine = rhs;
876: return(0);
877: }
881: /*@C
882: SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
883: it assumes a zero right hand side.
885: Collective on SNES
887: Input Parameter:
888: . snes - the SNES context
890: Output Parameter:
891: . rhs - the right hand side vector or PETSC_NULL for a zero right hand side
893: Level: intermediate
895: .keywords: SNES, nonlinear, get, function, right hand side
897: .seealso: SNESSetRhs(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
898: @*/
899: PetscErrorCode SNESGetRhs(SNES snes,Vec *rhs)
900: {
904: *rhs = snes->afine;
905: return(0);
906: }
910: /*@
911: SNESComputeFunction - Calls the function that has been set with
912: SNESSetFunction().
914: Collective on SNES
916: Input Parameters:
917: + snes - the SNES context
918: - x - input vector
920: Output Parameter:
921: . y - function vector, as set by SNESSetFunction()
923: Notes:
924: SNESComputeFunction() is typically used within nonlinear solvers
925: implementations, so most users would not generally call this routine
926: themselves.
928: Level: developer
930: .keywords: SNES, nonlinear, compute, function
932: .seealso: SNESSetFunction(), SNESGetFunction()
933: @*/
934: PetscErrorCode SNESComputeFunction(SNES snes,Vec x,Vec y)
935: {
946: if (snes->ops->computefunction) {
947: PetscStackPush("SNES user function");
948: CHKMEMQ;
949: (*snes->ops->computefunction)(snes,x,y,snes->funP);
950: CHKMEMQ;
951: PetscStackPop;
952: if (PetscExceptionValue(ierr)) {
954: }
955:
956: } else if (snes->afine) {
957: MatMult(snes->jacobian, x, y);
958: } else {
959: SETERRQ(PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() before SNESComputeFunction(), likely called from SNESSolve().");
960: }
961: if (snes->afine) {
962: VecAXPY(y,-1.0,snes->afine);
963: }
964: snes->nfuncs++;
966: return(0);
967: }
971: /*@
972: SNESComputeJacobian - Computes the Jacobian matrix that has been
973: set with SNESSetJacobian().
975: Collective on SNES and Mat
977: Input Parameters:
978: + snes - the SNES context
979: - x - input vector
981: Output Parameters:
982: + A - Jacobian matrix
983: . B - optional preconditioning matrix
984: - flag - flag indicating matrix structure (one of, SAME_NONZERO_PATTERN,DIFFERENT_NONZERO_PATTERN,SAME_PRECONDITIONER)
986: Notes:
987: Most users should not need to explicitly call this routine, as it
988: is used internally within the nonlinear solvers.
990: See KSPSetOperators() for important information about setting the
991: flag parameter.
993: Level: developer
995: .keywords: SNES, compute, Jacobian, matrix
997: .seealso: SNESSetJacobian(), KSPSetOperators(), MatStructure
998: @*/
999: PetscErrorCode SNESComputeJacobian(SNES snes,Vec X,Mat *A,Mat *B,MatStructure *flg)
1000: {
1008: if (!snes->ops->computejacobian) return(0);
1010: *flg = DIFFERENT_NONZERO_PATTERN;
1011: PetscStackPush("SNES user Jacobian function");
1012: CHKMEMQ;
1013: (*snes->ops->computejacobian)(snes,X,A,B,flg,snes->jacP);
1014: CHKMEMQ;
1015: PetscStackPop;
1017: /* make sure user returned a correct Jacobian and preconditioner */
1020: return(0);
1021: }
1025: /*@C
1026: SNESSetJacobian - Sets the function to compute Jacobian as well as the
1027: location to store the matrix.
1029: Collective on SNES and Mat
1031: Input Parameters:
1032: + snes - the SNES context
1033: . A - Jacobian matrix
1034: . B - preconditioner matrix (usually same as the Jacobian)
1035: . func - Jacobian evaluation routine
1036: - ctx - [optional] user-defined context for private data for the
1037: Jacobian evaluation routine (may be PETSC_NULL)
1039: Calling sequence of func:
1040: $ func (SNES snes,Vec x,Mat *A,Mat *B,int *flag,void *ctx);
1042: + x - input vector
1043: . A - Jacobian matrix
1044: . B - preconditioner matrix, usually the same as A
1045: . flag - flag indicating information about the preconditioner matrix
1046: structure (same as flag in KSPSetOperators()), one of SAME_NONZERO_PATTERN,DIFFERENT_NONZERO_PATTERN,SAME_PRECONDITIONER
1047: - ctx - [optional] user-defined Jacobian context
1049: Notes:
1050: See KSPSetOperators() for important information about setting the flag
1051: output parameter in the routine func(). Be sure to read this information!
1053: The routine func() takes Mat * as the matrix arguments rather than Mat.
1054: This allows the Jacobian evaluation routine to replace A and/or B with a
1055: completely new new matrix structure (not just different matrix elements)
1056: when appropriate, for instance, if the nonzero structure is changing
1057: throughout the global iterations.
1059: Level: beginner
1061: .keywords: SNES, nonlinear, set, Jacobian, matrix
1063: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESDefaultComputeJacobianColor(), MatStructure
1064: @*/
1065: PetscErrorCode SNESSetJacobian(SNES snes,Mat A,Mat B,PetscErrorCode (*func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void *ctx)
1066: {
1075: if (func) snes->ops->computejacobian = func;
1076: if (ctx) snes->jacP = ctx;
1077: if (A) {
1078: PetscObjectReference((PetscObject)A);
1079: if (snes->jacobian) {MatDestroy(snes->jacobian);}
1080: snes->jacobian = A;
1081: }
1082: if (B) {
1083: PetscObjectReference((PetscObject)B);
1084: if (snes->jacobian_pre) {MatDestroy(snes->jacobian_pre);}
1085: snes->jacobian_pre = B;
1086: }
1087: return(0);
1088: }
1092: /*@C
1093: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
1094: provided context for evaluating the Jacobian.
1096: Not Collective, but Mat object will be parallel if SNES object is
1098: Input Parameter:
1099: . snes - the nonlinear solver context
1101: Output Parameters:
1102: + A - location to stash Jacobian matrix (or PETSC_NULL)
1103: . B - location to stash preconditioner matrix (or PETSC_NULL)
1104: . func - location to put Jacobian function (or PETSC_NULL)
1105: - ctx - location to stash Jacobian ctx (or PETSC_NULL)
1107: Level: advanced
1109: .seealso: SNESSetJacobian(), SNESComputeJacobian()
1110: @*/
1111: PetscErrorCode SNESGetJacobian(SNES snes,Mat *A,Mat *B,PetscErrorCode (**func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void **ctx)
1112: {
1115: if (A) *A = snes->jacobian;
1116: if (B) *B = snes->jacobian_pre;
1117: if (func) *func = snes->ops->computejacobian;
1118: if (ctx) *ctx = snes->jacP;
1119: return(0);
1120: }
1122: /* ----- Routines to initialize and destroy a nonlinear solver ---- */
1123: EXTERN PetscErrorCode SNESDefaultMatrixFreeCreate2(SNES,Vec,Mat*);
1127: /*@
1128: SNESSetUp - Sets up the internal data structures for the later use
1129: of a nonlinear solver.
1131: Collective on SNES
1133: Input Parameters:
1134: . snes - the SNES context
1136: Notes:
1137: For basic use of the SNES solvers the user need not explicitly call
1138: SNESSetUp(), since these actions will automatically occur during
1139: the call to SNESSolve(). However, if one wishes to control this
1140: phase separately, SNESSetUp() should be called after SNESCreate()
1141: and optional routines of the form SNESSetXXX(), but before SNESSolve().
1143: Level: advanced
1145: .keywords: SNES, nonlinear, setup
1147: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
1148: @*/
1149: PetscErrorCode SNESSetUp(SNES snes)
1150: {
1152: PetscTruth flg;
1156: if (snes->setupcalled) return(0);
1158: PetscOptionsHasName(snes->prefix,"-snes_mf_operator",&flg);
1159: /*
1160: This version replaces the user provided Jacobian matrix with a
1161: matrix-free version but still employs the user-provided preconditioner matrix
1162: */
1163: if (flg) {
1164: Mat J;
1165: MatCreateSNESMF(snes,&J);
1166: MatMFFDSetFromOptions(J);
1167: PetscInfo(snes,"Setting default matrix-free operator routines\n");
1168: SNESSetJacobian(snes,J,0,0,0);
1169: MatDestroy(J);
1170: }
1172: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_SINGLE) && !defined(PETSC_USE_MAT_SINGLE) && !defined(PETSC_USE_LONG_DOUBLE) && !defined(PETSC_USE_INT)
1173: PetscOptionsHasName(snes->prefix,"-snes_mf_operator2",&flg);
1174: if (flg) {
1175: Mat J;
1176: SNESDefaultMatrixFreeCreate2(snes,snes->vec_sol,&J);
1177: PetscInfo(snes,"Setting default matrix-free operator routines (version 2)\n");
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;
1192: /* create and set matrix-free operator */
1193: MatCreateSNESMF(snes,&J);
1194: MatMFFDSetFromOptions(J);
1195: PetscInfo(snes,"Setting default matrix-free operator routines\n");
1196: SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,snes->funP);
1197: MatDestroy(J);
1198: /* force no preconditioner */
1199: SNESGetKSP(snes,&ksp);
1200: KSPGetPC(ksp,&pc);
1201: PetscTypeCompare((PetscObject)pc,PCSHELL,&flg);
1202: if (!flg) {
1203: PetscInfo(snes,"Setting default matrix-free preconditioner routines;\nThat is no preconditioner is being used\n");
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) {
1215: SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Must call SNESSetJacobian() first \n or use -snes_mf option");
1216: }
1217: if (snes->vec_func == snes->vec_sol) {
1218: SETERRQ(PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
1219: }
1221: if (!snes->type_name) {
1222: SNESSetType(snes,SNESLS);
1223: }
1224: if (snes->ops->setup) {
1225: (*snes->ops->setup)(snes);
1226: }
1227: snes->setupcalled = PETSC_TRUE;
1228: return(0);
1229: }
1233: /*@
1234: SNESDestroy - Destroys the nonlinear solver context that was created
1235: with SNESCreate().
1237: Collective on SNES
1239: Input Parameter:
1240: . snes - the SNES context
1242: Level: beginner
1244: .keywords: SNES, nonlinear, destroy
1246: .seealso: SNESCreate(), SNESSolve()
1247: @*/
1248: PetscErrorCode SNESDestroy(SNES snes)
1249: {
1254: if (--snes->refct > 0) return(0);
1256: /* if memory was published with AMS then destroy it */
1257: PetscObjectDepublish(snes);
1259: if (snes->ops->destroy) {(*(snes)->ops->destroy)(snes);}
1260: PetscFree(snes->kspconvctx);
1261: if (snes->jacobian) {MatDestroy(snes->jacobian);}
1262: if (snes->jacobian_pre) {MatDestroy(snes->jacobian_pre);}
1263: if (snes->afine) {VecDestroy(snes->afine);}
1264: KSPDestroy(snes->ksp);
1265: if (snes->vwork) {VecDestroyVecs(snes->vwork,snes->nvwork);}
1266: SNESMonitorCancel(snes);
1267: PetscHeaderDestroy(snes);
1268: return(0);
1269: }
1271: /* ----------- Routines to set solver parameters ---------- */
1275: /*@
1276: SNESSetTolerances - Sets various parameters used in convergence tests.
1278: Collective on SNES
1280: Input Parameters:
1281: + snes - the SNES context
1282: . abstol - absolute convergence tolerance
1283: . rtol - relative convergence tolerance
1284: . stol - convergence tolerance in terms of the norm
1285: of the change in the solution between steps
1286: . maxit - maximum number of iterations
1287: - maxf - maximum number of function evaluations
1289: Options Database Keys:
1290: + -snes_atol <abstol> - Sets abstol
1291: . -snes_rtol <rtol> - Sets rtol
1292: . -snes_stol <stol> - Sets stol
1293: . -snes_max_it <maxit> - Sets maxit
1294: - -snes_max_funcs <maxf> - Sets maxf
1296: Notes:
1297: The default maximum number of iterations is 50.
1298: The default maximum number of function evaluations is 1000.
1300: Level: intermediate
1302: .keywords: SNES, nonlinear, set, convergence, tolerances
1304: .seealso: SNESSetTrustRegionTolerance()
1305: @*/
1306: PetscErrorCode SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
1307: {
1310: if (abstol != PETSC_DEFAULT) snes->abstol = abstol;
1311: if (rtol != PETSC_DEFAULT) snes->rtol = rtol;
1312: if (stol != PETSC_DEFAULT) snes->xtol = stol;
1313: if (maxit != PETSC_DEFAULT) snes->max_its = maxit;
1314: if (maxf != PETSC_DEFAULT) snes->max_funcs = maxf;
1315: return(0);
1316: }
1320: /*@
1321: SNESGetTolerances - Gets various parameters used in convergence tests.
1323: Not Collective
1325: Input Parameters:
1326: + snes - the SNES context
1327: . abstol - absolute convergence tolerance