Actual source code: snes.c
1: #include <petsc/private/snesimpl.h>
2: #include <petscdmshell.h>
3: #include <petscdraw.h>
4: #include <petscds.h>
5: #include <petscdmadaptor.h>
6: #include <petscconvest.h>
8: PetscBool SNESRegisterAllCalled = PETSC_FALSE;
9: PetscFunctionList SNESList = NULL;
11: /* Logging support */
12: PetscClassId SNES_CLASSID, DMSNES_CLASSID;
13: PetscLogEvent SNES_Solve, SNES_SetUp, SNES_FunctionEval, SNES_JacobianEval, SNES_NGSEval, SNES_NGSFuncEval, SNES_NPCSolve, SNES_ObjectiveEval;
15: /*@
16: SNESSetErrorIfNotConverged - Causes `SNESSolve()` to generate an error immediately if the solver has not converged.
18: Logically Collective
20: Input Parameters:
21: + snes - iterative context obtained from `SNESCreate()`
22: - flg - `PETSC_TRUE` indicates you want the error generated
24: Options Database Key:
25: . -snes_error_if_not_converged <true,false> - cause an immediate error condition and stop the program if the solver does not converge
27: Level: intermediate
29: Note:
30: Normally PETSc continues if a solver fails to converge, you can call `SNESGetConvergedReason()` after a `SNESSolve()`
31: to determine if it has converged. Otherwise the solution may be inaccurate or wrong
33: .seealso: [](chapter_snes), `SNES`, `SNESGetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
34: @*/
35: PetscErrorCode SNESSetErrorIfNotConverged(SNES snes, PetscBool flg)
36: {
37: PetscFunctionBegin;
40: snes->errorifnotconverged = flg;
41: PetscFunctionReturn(PETSC_SUCCESS);
42: }
44: /*@
45: SNESGetErrorIfNotConverged - Indicates if `SNESSolve()` will generate an error if the solver does not converge?
47: Not Collective
49: Input Parameter:
50: . snes - iterative context obtained from `SNESCreate()`
52: Output Parameter:
53: . flag - `PETSC_TRUE` if it will generate an error, else `PETSC_FALSE`
55: Level: intermediate
57: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESSetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
58: @*/
59: PetscErrorCode SNESGetErrorIfNotConverged(SNES snes, PetscBool *flag)
60: {
61: PetscFunctionBegin;
64: *flag = snes->errorifnotconverged;
65: PetscFunctionReturn(PETSC_SUCCESS);
66: }
68: /*@
69: SNESSetAlwaysComputesFinalResidual - tells the `SNES` to always compute the residual (nonlinear function value) at the final solution
71: Logically Collective
73: Input Parameters:
74: + snes - the shell `SNES`
75: - flg - `PETSC_TRUE` to always compute the residual
77: Level: advanced
79: Note:
80: Some solvers (such as smoothers in a `SNESFAS`) do not need the residual computed at the final solution so skip computing it
81: to save time.
83: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESGetAlwaysComputesFinalResidual()`
84: @*/
85: PetscErrorCode SNESSetAlwaysComputesFinalResidual(SNES snes, PetscBool flg)
86: {
87: PetscFunctionBegin;
89: snes->alwayscomputesfinalresidual = flg;
90: PetscFunctionReturn(PETSC_SUCCESS);
91: }
93: /*@
94: SNESGetAlwaysComputesFinalResidual - checks if the `SNES` always computes the residual at the final solution
96: Logically Collective
98: Input Parameter:
99: . snes - the `SNES` context
101: Output Parameter:
102: . flg - `PETSC_TRUE` if the residual is computed
104: Level: advanced
106: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESSetAlwaysComputesFinalResidual()`
107: @*/
108: PetscErrorCode SNESGetAlwaysComputesFinalResidual(SNES snes, PetscBool *flg)
109: {
110: PetscFunctionBegin;
112: *flg = snes->alwayscomputesfinalresidual;
113: PetscFunctionReturn(PETSC_SUCCESS);
114: }
116: /*@
117: SNESSetFunctionDomainError - tells `SNES` that the input vector, a proposed new solution, to your function you provided to `SNESSetFunction()` is not
118: in the functions domain. For example, a step with negative pressure.
120: Logically Collective
122: Input Parameter:
123: . snes - the `SNES` context
125: Level: advanced
127: Note:
128: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
129: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
131: .seealso: [](chapter_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunction`, `SNESSetJacobianDomainError()`, `SNESVISetVariableBounds()`,
132: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
133: @*/
134: PetscErrorCode SNESSetFunctionDomainError(SNES snes)
135: {
136: PetscFunctionBegin;
138: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates input vector is not in the function domain");
139: snes->domainerror = PETSC_TRUE;
140: PetscFunctionReturn(PETSC_SUCCESS);
141: }
143: /*@
144: SNESSetJacobianDomainError - tells `SNES` that the function you provided to `SNESSetJacobian()` at the proposed step. For example there is a negative element transformation.
146: Logically Collective
148: Input Parameter:
149: . snes - the `SNES` context
151: Level: advanced
153: Note:
154: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
155: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
157: .seealso: [](chapter_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunction()`, `SNESSetFunctionDomainError()`, `SNESVISetVariableBounds()`,
158: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
159: @*/
160: PetscErrorCode SNESSetJacobianDomainError(SNES snes)
161: {
162: PetscFunctionBegin;
164: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates computeJacobian does not make sense");
165: snes->jacobiandomainerror = PETSC_TRUE;
166: PetscFunctionReturn(PETSC_SUCCESS);
167: }
169: /*@
170: SNESSetCheckJacobianDomainError - tells `SNESSolve()` whether to check if the user called `SNESSetJacobianDomainError()` Jacobian domain error after
171: each Jacobian evaluation. By default, we check Jacobian domain error in the debug mode, and do not check it in the optimized mode.
173: Logically Collective
175: Input Parameters:
176: + snes - the `SNES` context
177: - flg - indicates if or not to check Jacobian domain error after each Jacobian evaluation
179: Level: advanced
181: Note:
182: Checks require one extra parallel synchronization for each Jacobian evaluation
184: .seealso: [](chapter_snes), `SNES`, `SNESConvergedReason`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunction()`, `SNESSetFunctionDomainError()`, `SNESGetCheckJacobianDomainError()`
185: @*/
186: PetscErrorCode SNESSetCheckJacobianDomainError(SNES snes, PetscBool flg)
187: {
188: PetscFunctionBegin;
190: snes->checkjacdomainerror = flg;
191: PetscFunctionReturn(PETSC_SUCCESS);
192: }
194: /*@
195: SNESGetCheckJacobianDomainError - Get an indicator whether or not we are checking Jacobian domain errors after each Jacobian evaluation.
197: Logically Collective
199: Input Parameter:
200: . snes - the `SNES` context
202: Output Parameter:
203: . flg - `PETSC_FALSE` indicates that we don't check Jacobian domain errors after each Jacobian evaluation
205: Level: advanced
207: .seealso: [](chapter_snes), `SNES`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunction()`, `SNESSetFunctionDomainError()`, `SNESSetCheckJacobianDomainError()`
208: @*/
209: PetscErrorCode SNESGetCheckJacobianDomainError(SNES snes, PetscBool *flg)
210: {
211: PetscFunctionBegin;
214: *flg = snes->checkjacdomainerror;
215: PetscFunctionReturn(PETSC_SUCCESS);
216: }
218: /*@
219: SNESGetFunctionDomainError - Gets the status of the domain error after a call to `SNESComputeFunction()`;
221: Logically Collective
223: Input Parameter:
224: . snes - the `SNES` context
226: Output Parameter:
227: . domainerror - Set to `PETSC_TRUE` if there's a domain error; `PETSC_FALSE` otherwise.
229: Level: developer
231: .seealso: [](chapter_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`
232: @*/
233: PetscErrorCode SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
234: {
235: PetscFunctionBegin;
238: *domainerror = snes->domainerror;
239: PetscFunctionReturn(PETSC_SUCCESS);
240: }
242: /*@
243: SNESGetJacobianDomainError - Gets the status of the Jacobian domain error after a call to `SNESComputeJacobian()`;
245: Logically Collective
247: Input Parameter:
248: . snes - the `SNES` context
250: Output Parameter:
251: . domainerror - Set to `PETSC_TRUE` if there's a Jacobian domain error; `PETSC_FALSE` otherwise.
253: Level: advanced
255: .seealso: [](chapter_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`, `SNESGetFunctionDomainError()`
256: @*/
257: PetscErrorCode SNESGetJacobianDomainError(SNES snes, PetscBool *domainerror)
258: {
259: PetscFunctionBegin;
262: *domainerror = snes->jacobiandomainerror;
263: PetscFunctionReturn(PETSC_SUCCESS);
264: }
266: /*@C
267: SNESLoad - Loads a `SNES` that has been stored in `PETSCVIEWERBINARY` with `SNESView()`.
269: Collective
271: Input Parameters:
272: + newdm - the newly loaded `SNES`, this needs to have been created with `SNESCreate()` or
273: some related function before a call to `SNESLoad()`.
274: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()`
276: Level: intermediate
278: Note:
279: The type is determined by the data in the file, any type set into the `SNES` before this call is ignored.
281: .seealso: [](chapter_snes), `SNES`, `PetscViewer`, `SNESCreate()`, `SNESType`, `PetscViewerBinaryOpen()`, `SNESView()`, `MatLoad()`, `VecLoad()`
282: @*/
283: PetscErrorCode SNESLoad(SNES snes, PetscViewer viewer)
284: {
285: PetscBool isbinary;
286: PetscInt classid;
287: char type[256];
288: KSP ksp;
289: DM dm;
290: DMSNES dmsnes;
292: PetscFunctionBegin;
295: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
296: PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
298: PetscCall(PetscViewerBinaryRead(viewer, &classid, 1, NULL, PETSC_INT));
299: PetscCheck(classid == SNES_FILE_CLASSID, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Not SNES next in file");
300: PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
301: PetscCall(SNESSetType(snes, type));
302: PetscTryTypeMethod(snes, load, viewer);
303: PetscCall(SNESGetDM(snes, &dm));
304: PetscCall(DMGetDMSNES(dm, &dmsnes));
305: PetscCall(DMSNESLoad(dmsnes, viewer));
306: PetscCall(SNESGetKSP(snes, &ksp));
307: PetscCall(KSPLoad(ksp, viewer));
308: PetscFunctionReturn(PETSC_SUCCESS);
309: }
311: #include <petscdraw.h>
312: #if defined(PETSC_HAVE_SAWS)
313: #include <petscviewersaws.h>
314: #endif
316: /*@C
317: SNESViewFromOptions - View a `SNES` based on values in the options database
319: Collective
321: Input Parameters:
322: + A - the `SNES` context
323: . obj - Optional object that provides the options prefix for the checks
324: - name - command line option
326: Level: intermediate
328: .seealso: [](chapter_snes), `SNES`, `SNESView`, `PetscObjectViewFromOptions()`, `SNESCreate()`
329: @*/
330: PetscErrorCode SNESViewFromOptions(SNES A, PetscObject obj, const char name[])
331: {
332: PetscFunctionBegin;
334: PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
335: PetscFunctionReturn(PETSC_SUCCESS);
336: }
338: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES, Vec, Mat, Mat, void *);
340: /*@C
341: SNESView - Prints or visualizes the `SNES` data structure.
343: Collective
345: Input Parameters:
346: + snes - the `SNES` context
347: - viewer - the `PetscViewer`
349: Options Database Key:
350: . -snes_view - Calls `SNESView()` at end of `SNESSolve()`
352: Level: beginner
354: Notes:
355: The available visualization contexts include
356: + `PETSC_VIEWER_STDOUT_SELF` - standard output (default)
357: - `PETSC_VIEWER_STDOUT_WORLD` - synchronized standard
358: output where only the first processor opens
359: the file. All other processors send their
360: data to the first processor to print.
362: The available formats include
363: + `PETSC_VIEWER_DEFAULT` - standard output (default)
364: - `PETSC_VIEWER_ASCII_INFO_DETAIL` - more verbose output for `SNESNASM`
366: The user can open an alternative visualization context with
367: `PetscViewerASCIIOpen()` - output to a specified file.
369: In the debugger you can do "call `SNESView`(snes,0)" to display the `SNES` solver. (The same holds for any PETSc object viewer).
371: .seealso: [](chapter_snes), `SNES`, `SNESLoad()`, `SNESCreate()`, `PetscViewerASCIIOpen()`
372: @*/
373: PetscErrorCode SNESView(SNES snes, PetscViewer viewer)
374: {
375: SNESKSPEW *kctx;
376: KSP ksp;
377: SNESLineSearch linesearch;
378: PetscBool iascii, isstring, isbinary, isdraw;
379: DMSNES dmsnes;
380: #if defined(PETSC_HAVE_SAWS)
381: PetscBool issaws;
382: #endif
384: PetscFunctionBegin;
386: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &viewer));
388: PetscCheckSameComm(snes, 1, viewer, 2);
390: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
391: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
392: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
393: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
394: #if defined(PETSC_HAVE_SAWS)
395: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
396: #endif
397: if (iascii) {
398: SNESNormSchedule normschedule;
399: DM dm;
400: PetscErrorCode (*cJ)(SNES, Vec, Mat, Mat, void *);
401: void *ctx;
402: const char *pre = "";
404: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)snes, viewer));
405: if (!snes->setupcalled) PetscCall(PetscViewerASCIIPrintf(viewer, " SNES has not been set up so information may be incomplete\n"));
406: if (snes->ops->view) {
407: PetscCall(PetscViewerASCIIPushTab(viewer));
408: PetscUseTypeMethod(snes, view, viewer);
409: PetscCall(PetscViewerASCIIPopTab(viewer));
410: }
411: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=%" PetscInt_FMT "\n", snes->max_its, snes->max_funcs));
412: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%g, absolute=%g, solution=%g\n", (double)snes->rtol, (double)snes->abstol, (double)snes->stol));
413: if (snes->usesksp) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of linear solver iterations=%" PetscInt_FMT "\n", snes->linear_its));
414: PetscCall(PetscViewerASCIIPrintf(viewer, " total number of function evaluations=%" PetscInt_FMT "\n", snes->nfuncs));
415: PetscCall(SNESGetNormSchedule(snes, &normschedule));
416: if (normschedule > 0) PetscCall(PetscViewerASCIIPrintf(viewer, " norm schedule %s\n", SNESNormSchedules[normschedule]));
417: if (snes->gridsequence) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of grid sequence refinements=%" PetscInt_FMT "\n", snes->gridsequence));
418: if (snes->ksp_ewconv) {
419: kctx = (SNESKSPEW *)snes->kspconvctx;
420: if (kctx) {
421: PetscCall(PetscViewerASCIIPrintf(viewer, " Eisenstat-Walker computation of KSP relative tolerance (version %" PetscInt_FMT ")\n", kctx->version));
422: PetscCall(PetscViewerASCIIPrintf(viewer, " rtol_0=%g, rtol_max=%g, threshold=%g\n", (double)kctx->rtol_0, (double)kctx->rtol_max, (double)kctx->threshold));
423: PetscCall(PetscViewerASCIIPrintf(viewer, " gamma=%g, alpha=%g, alpha2=%g\n", (double)kctx->gamma, (double)kctx->alpha, (double)kctx->alpha2));
424: }
425: }
426: if (snes->lagpreconditioner == -1) {
427: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is never rebuilt\n"));
428: } else if (snes->lagpreconditioner > 1) {
429: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is rebuilt every %" PetscInt_FMT " new Jacobians\n", snes->lagpreconditioner));
430: }
431: if (snes->lagjacobian == -1) {
432: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is never rebuilt\n"));
433: } else if (snes->lagjacobian > 1) {
434: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is rebuilt every %" PetscInt_FMT " SNES iterations\n", snes->lagjacobian));
435: }
436: PetscCall(SNESGetDM(snes, &dm));
437: PetscCall(DMSNESGetJacobian(dm, &cJ, &ctx));
438: if (snes->mf_operator) {
439: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing\n"));
440: pre = "Preconditioning ";
441: }
442: if (cJ == SNESComputeJacobianDefault) {
443: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences one column at a time\n", pre));
444: } else if (cJ == SNESComputeJacobianDefaultColor) {
445: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences with coloring\n", pre));
446: /* it slightly breaks data encapsulation for access the DMDA information directly */
447: } else if (cJ == SNESComputeJacobian_DMDA) {
448: MatFDColoring fdcoloring;
449: PetscCall(PetscObjectQuery((PetscObject)dm, "DMDASNES_FDCOLORING", (PetscObject *)&fdcoloring));
450: if (fdcoloring) {
451: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using colored finite differences on a DMDA\n", pre));
452: } else {
453: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using a DMDA local Jacobian\n", pre));
454: }
455: } else if (snes->mf) {
456: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing, no explicit Jacobian\n"));
457: }
458: } else if (isstring) {
459: const char *type;
460: PetscCall(SNESGetType(snes, &type));
461: PetscCall(PetscViewerStringSPrintf(viewer, " SNESType: %-7.7s", type));
462: PetscTryTypeMethod(snes, view, viewer);
463: } else if (isbinary) {
464: PetscInt classid = SNES_FILE_CLASSID;
465: MPI_Comm comm;
466: PetscMPIInt rank;
467: char type[256];
469: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
470: PetscCallMPI(MPI_Comm_rank(comm, &rank));
471: if (rank == 0) {
472: PetscCall(PetscViewerBinaryWrite(viewer, &classid, 1, PETSC_INT));
473: PetscCall(PetscStrncpy(type, ((PetscObject)snes)->type_name, sizeof(type)));
474: PetscCall(PetscViewerBinaryWrite(viewer, type, sizeof(type), PETSC_CHAR));
475: }
476: PetscTryTypeMethod(snes, view, viewer);
477: } else if (isdraw) {
478: PetscDraw draw;
479: char str[36];
480: PetscReal x, y, bottom, h;
482: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
483: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
484: PetscCall(PetscStrncpy(str, "SNES: ", sizeof(str)));
485: PetscCall(PetscStrlcat(str, ((PetscObject)snes)->type_name, sizeof(str)));
486: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_BLUE, PETSC_DRAW_BLACK, str, NULL, &h));
487: bottom = y - h;
488: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
489: PetscTryTypeMethod(snes, view, viewer);
490: #if defined(PETSC_HAVE_SAWS)
491: } else if (issaws) {
492: PetscMPIInt rank;
493: const char *name;
495: PetscCall(PetscObjectGetName((PetscObject)snes, &name));
496: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
497: if (!((PetscObject)snes)->amsmem && rank == 0) {
498: char dir[1024];
500: PetscCall(PetscObjectViewSAWs((PetscObject)snes, viewer));
501: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/its", name));
502: PetscCallSAWs(SAWs_Register, (dir, &snes->iter, 1, SAWs_READ, SAWs_INT));
503: if (!snes->conv_hist) PetscCall(SNESSetConvergenceHistory(snes, NULL, NULL, PETSC_DECIDE, PETSC_TRUE));
504: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/conv_hist", name));
505: PetscCallSAWs(SAWs_Register, (dir, snes->conv_hist, 10, SAWs_READ, SAWs_DOUBLE));
506: }
507: #endif
508: }
509: if (snes->linesearch) {
510: PetscCall(SNESGetLineSearch(snes, &linesearch));
511: PetscCall(PetscViewerASCIIPushTab(viewer));
512: PetscCall(SNESLineSearchView(linesearch, viewer));
513: PetscCall(PetscViewerASCIIPopTab(viewer));
514: }
515: if (snes->npc && snes->usesnpc) {
516: PetscCall(PetscViewerASCIIPushTab(viewer));
517: PetscCall(SNESView(snes->npc, viewer));
518: PetscCall(PetscViewerASCIIPopTab(viewer));
519: }
520: PetscCall(PetscViewerASCIIPushTab(viewer));
521: PetscCall(DMGetDMSNES(snes->dm, &dmsnes));
522: PetscCall(DMSNESView(dmsnes, viewer));
523: PetscCall(PetscViewerASCIIPopTab(viewer));
524: if (snes->usesksp) {
525: PetscCall(SNESGetKSP(snes, &ksp));
526: PetscCall(PetscViewerASCIIPushTab(viewer));
527: PetscCall(KSPView(ksp, viewer));
528: PetscCall(PetscViewerASCIIPopTab(viewer));
529: }
530: if (isdraw) {
531: PetscDraw draw;
532: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
533: PetscCall(PetscDrawPopCurrentPoint(draw));
534: }
535: PetscFunctionReturn(PETSC_SUCCESS);
536: }
538: /*
539: We retain a list of functions that also take SNES command
540: line options. These are called at the end SNESSetFromOptions()
541: */
542: #define MAXSETFROMOPTIONS 5
543: static PetscInt numberofsetfromoptions;
544: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);
546: /*@C
547: SNESAddOptionsChecker - Adds an additional function to check for `SNES` options.
549: Not Collective
551: Input Parameter:
552: . snescheck - function that checks for options
554: Level: developer
556: .seealso: [](chapter_snes), `SNES`, `SNESSetFromOptions()`
557: @*/
558: PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
559: {
560: PetscFunctionBegin;
561: PetscCheck(numberofsetfromoptions < MAXSETFROMOPTIONS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %d allowed", MAXSETFROMOPTIONS);
562: othersetfromoptions[numberofsetfromoptions++] = snescheck;
563: PetscFunctionReturn(PETSC_SUCCESS);
564: }
566: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
567: {
568: Mat J;
569: MatNullSpace nullsp;
571: PetscFunctionBegin;
574: if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
575: Mat A = snes->jacobian, B = snes->jacobian_pre;
576: PetscCall(MatCreateVecs(A ? A : B, NULL, &snes->vec_func));
577: }
579: PetscCheck(version == 1 || version == 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator routines, only version 1 and 2");
580: if (version == 1) {
581: PetscCall(MatCreateSNESMF(snes, &J));
582: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
583: PetscCall(MatSetFromOptions(J));
584: /* TODO: the version 2 code should be merged into the MatCreateSNESMF() and MatCreateMFFD() infrastructure and then removed */
585: } else /* if (version == 2) */ {
586: PetscCheck(snes->vec_func, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "SNESSetFunction() must be called first");
587: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
588: PetscCall(MatCreateSNESMFMore(snes, snes->vec_func, &J));
589: #else
590: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "matrix-free operator routines (version 2)");
591: #endif
592: }
594: /* attach any user provided null space that was on Amat to the newly created matrix free matrix */
595: if (snes->jacobian) {
596: PetscCall(MatGetNullSpace(snes->jacobian, &nullsp));
597: if (nullsp) PetscCall(MatSetNullSpace(J, nullsp));
598: }
600: PetscCall(PetscInfo(snes, "Setting default matrix-free operator routines (version %" PetscInt_FMT ")\n", version));
601: if (hasOperator) {
602: /* This version replaces the user provided Jacobian matrix with a
603: matrix-free version but still employs the user-provided preconditioner matrix. */
604: PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
605: } else {
606: /* This version replaces both the user-provided Jacobian and the user-
607: provided preconditioner Jacobian with the default matrix free version. */
608: if (snes->npcside == PC_LEFT && snes->npc) {
609: if (!snes->jacobian) PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
610: } else {
611: KSP ksp;
612: PC pc;
613: PetscBool match;
615: PetscCall(SNESSetJacobian(snes, J, J, MatMFFDComputeJacobian, NULL));
616: /* Force no preconditioner */
617: PetscCall(SNESGetKSP(snes, &ksp));
618: PetscCall(KSPGetPC(ksp, &pc));
619: PetscCall(PetscObjectTypeCompareAny((PetscObject)pc, &match, PCSHELL, PCH2OPUS, ""));
620: if (!match) {
621: PetscCall(PetscInfo(snes, "Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n"));
622: PetscCall(PCSetType(pc, PCNONE));
623: }
624: }
625: }
626: PetscCall(MatDestroy(&J));
627: PetscFunctionReturn(PETSC_SUCCESS);
628: }
630: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine, Mat Restrict, Vec Rscale, Mat Inject, DM dmcoarse, void *ctx)
631: {
632: SNES snes = (SNES)ctx;
633: Vec Xfine, Xfine_named = NULL, Xcoarse;
635: PetscFunctionBegin;
636: if (PetscLogPrintInfo) {
637: PetscInt finelevel, coarselevel, fineclevel, coarseclevel;
638: PetscCall(DMGetRefineLevel(dmfine, &finelevel));
639: PetscCall(DMGetCoarsenLevel(dmfine, &fineclevel));
640: PetscCall(DMGetRefineLevel(dmcoarse, &coarselevel));
641: PetscCall(DMGetCoarsenLevel(dmcoarse, &coarseclevel));
642: PetscCall(PetscInfo(dmfine, "Restricting SNES solution vector from level %" PetscInt_FMT "-%" PetscInt_FMT " to level %" PetscInt_FMT "-%" PetscInt_FMT "\n", finelevel, fineclevel, coarselevel, coarseclevel));
643: }
644: if (dmfine == snes->dm) Xfine = snes->vec_sol;
645: else {
646: PetscCall(DMGetNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
647: Xfine = Xfine_named;
648: }
649: PetscCall(DMGetNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
650: if (Inject) {
651: PetscCall(MatRestrict(Inject, Xfine, Xcoarse));
652: } else {
653: PetscCall(MatRestrict(Restrict, Xfine, Xcoarse));
654: PetscCall(VecPointwiseMult(Xcoarse, Xcoarse, Rscale));
655: }
656: PetscCall(DMRestoreNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
657: if (Xfine_named) PetscCall(DMRestoreNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
658: PetscFunctionReturn(PETSC_SUCCESS);
659: }
661: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm, DM dmc, void *ctx)
662: {
663: PetscFunctionBegin;
664: PetscCall(DMCoarsenHookAdd(dmc, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, ctx));
665: PetscFunctionReturn(PETSC_SUCCESS);
666: }
668: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
669: * safely call SNESGetDM() in their residual evaluation routine. */
670: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp, Mat A, Mat B, void *ctx)
671: {
672: SNES snes = (SNES)ctx;
673: Vec X, Xnamed = NULL;
674: DM dmsave;
675: void *ctxsave;
676: PetscErrorCode (*jac)(SNES, Vec, Mat, Mat, void *) = NULL;
678: PetscFunctionBegin;
679: dmsave = snes->dm;
680: PetscCall(KSPGetDM(ksp, &snes->dm));
681: if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
682: else { /* We are on a coarser level, this vec was initialized using a DM restrict hook */ PetscCall(DMGetNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
683: X = Xnamed;
684: PetscCall(SNESGetJacobian(snes, NULL, NULL, &jac, &ctxsave));
685: /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
686: if (jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, SNESComputeJacobianDefaultColor, NULL));
687: }
688: /* Make sure KSP DM has the Jacobian computation routine */
689: {
690: DMSNES sdm;
692: PetscCall(DMGetDMSNES(snes->dm, &sdm));
693: if (!sdm->ops->computejacobian) PetscCall(DMCopyDMSNES(dmsave, snes->dm));
694: }
695: /* Compute the operators */
696: PetscCall(SNESComputeJacobian(snes, X, A, B));
697: /* Put the previous context back */
698: if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, jac, ctxsave));
700: if (Xnamed) PetscCall(DMRestoreNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
701: snes->dm = dmsave;
702: PetscFunctionReturn(PETSC_SUCCESS);
703: }
705: /*@
706: SNESSetUpMatrices - ensures that matrices are available for `SNES` Newton-like methods, this is called by `SNESSetUp_XXX()`
708: Collective
710: Input Parameter:
711: . snes - `SNES` object to configure
713: Level: developer
715: Note:
716: If the matrices do not yet exist it attempts to create them based on options previously set for the `SNES` such as `-snes_mf`
718: .seealso: [](chapter_snes), `SNES`, `SNESSetUp()`
719: @*/
720: PetscErrorCode SNESSetUpMatrices(SNES snes)
721: {
722: DM dm;
723: DMSNES sdm;
725: PetscFunctionBegin;
726: PetscCall(SNESGetDM(snes, &dm));
727: PetscCall(DMGetDMSNES(dm, &sdm));
728: if (!snes->jacobian && snes->mf) {
729: Mat J;
730: void *functx;
731: PetscCall(MatCreateSNESMF(snes, &J));
732: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
733: PetscCall(MatSetFromOptions(J));
734: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
735: PetscCall(SNESSetJacobian(snes, J, J, NULL, NULL));
736: PetscCall(MatDestroy(&J));
737: } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
738: Mat J, B;
739: PetscCall(MatCreateSNESMF(snes, &J));
740: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
741: PetscCall(MatSetFromOptions(J));
742: PetscCall(DMCreateMatrix(snes->dm, &B));
743: /* sdm->computejacobian was already set to reach here */
744: PetscCall(SNESSetJacobian(snes, J, B, NULL, NULL));
745: PetscCall(MatDestroy(&J));
746: PetscCall(MatDestroy(&B));
747: } else if (!snes->jacobian_pre) {
748: PetscDS prob;
749: Mat J, B;
750: PetscBool hasPrec = PETSC_FALSE;
752: J = snes->jacobian;
753: PetscCall(DMGetDS(dm, &prob));
754: if (prob) PetscCall(PetscDSHasJacobianPreconditioner(prob, &hasPrec));
755: if (J) PetscCall(PetscObjectReference((PetscObject)J));
756: else if (hasPrec) PetscCall(DMCreateMatrix(snes->dm, &J));
757: PetscCall(DMCreateMatrix(snes->dm, &B));
758: PetscCall(SNESSetJacobian(snes, J ? J : B, B, NULL, NULL));
759: PetscCall(MatDestroy(&J));
760: PetscCall(MatDestroy(&B));
761: }
762: {
763: KSP ksp;
764: PetscCall(SNESGetKSP(snes, &ksp));
765: PetscCall(KSPSetComputeOperators(ksp, KSPComputeOperators_SNES, snes));
766: PetscCall(DMCoarsenHookAdd(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
767: }
768: PetscFunctionReturn(PETSC_SUCCESS);
769: }
771: static PetscErrorCode SNESMonitorPauseFinal_Internal(SNES snes)
772: {
773: PetscInt i;
775: PetscFunctionBegin;
776: if (!snes->pauseFinal) PetscFunctionReturn(PETSC_SUCCESS);
777: for (i = 0; i < snes->numbermonitors; ++i) {
778: PetscViewerAndFormat *vf = (PetscViewerAndFormat *)snes->monitorcontext[i];
779: PetscDraw draw;
780: PetscReal lpause;
782: if (!vf) continue;
783: if (vf->lg) {
784: if (!PetscCheckPointer(vf->lg, PETSC_OBJECT)) continue;
785: if (((PetscObject)vf->lg)->classid != PETSC_DRAWLG_CLASSID) continue;
786: PetscCall(PetscDrawLGGetDraw(vf->lg, &draw));
787: PetscCall(PetscDrawGetPause(draw, &lpause));
788: PetscCall(PetscDrawSetPause(draw, -1.0));
789: PetscCall(PetscDrawPause(draw));
790: PetscCall(PetscDrawSetPause(draw, lpause));
791: } else {
792: PetscBool isdraw;
794: if (!PetscCheckPointer(vf->viewer, PETSC_OBJECT)) continue;
795: if (((PetscObject)vf->viewer)->classid != PETSC_VIEWER_CLASSID) continue;
796: PetscCall(PetscObjectTypeCompare((PetscObject)vf->viewer, PETSCVIEWERDRAW, &isdraw));
797: if (!isdraw) continue;
798: PetscCall(PetscViewerDrawGetDraw(vf->viewer, 0, &draw));
799: PetscCall(PetscDrawGetPause(draw, &lpause));
800: PetscCall(PetscDrawSetPause(draw, -1.0));
801: PetscCall(PetscDrawPause(draw));
802: PetscCall(PetscDrawSetPause(draw, lpause));
803: }
804: }
805: PetscFunctionReturn(PETSC_SUCCESS);
806: }
808: /*@C
809: SNESMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user
811: Collective
813: Input Parameters:
814: + snes - `SNES` object you wish to monitor
815: . name - the monitor type one is seeking
816: . help - message indicating what monitoring is done
817: . manual - manual page for the monitor
818: . monitor - the monitor function
819: - monitorsetup - a function that is called once ONLY if the user selected this monitor that may set additional features of the `SNES` or `PetscViewer` objects
821: Options Database Key:
822: . -name - trigger the use of this monitor in `SNESSetFromOptions()`
824: Level: advanced
826: .seealso: [](chapter_snes), `PetscOptionsGetViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
827: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`
828: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`, `PetscOptionsBool()`,
829: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
830: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
831: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
832: `PetscOptionsFList()`, `PetscOptionsEList()`
833: @*/
834: PetscErrorCode SNESMonitorSetFromOptions(SNES snes, const char name[], const char help[], const char manual[], PetscErrorCode (*monitor)(SNES, PetscInt, PetscReal, PetscViewerAndFormat *), PetscErrorCode (*monitorsetup)(SNES, PetscViewerAndFormat *))
835: {
836: PetscViewer viewer;
837: PetscViewerFormat format;
838: PetscBool flg;
840: PetscFunctionBegin;
841: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, name, &viewer, &format, &flg));
842: if (flg) {
843: PetscViewerAndFormat *vf;
844: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
845: PetscCall(PetscObjectDereference((PetscObject)viewer));
846: if (monitorsetup) PetscCall((*monitorsetup)(snes, vf));
847: PetscCall(SNESMonitorSet(snes, (PetscErrorCode(*)(SNES, PetscInt, PetscReal, void *))monitor, vf, (PetscErrorCode(*)(void **))PetscViewerAndFormatDestroy));
848: }
849: PetscFunctionReturn(PETSC_SUCCESS);
850: }
852: PetscErrorCode SNESEWSetFromOptions_Private(SNESKSPEW *kctx, PetscBool print_api, MPI_Comm comm, const char *prefix)
853: {
854: const char *api = print_api ? "SNESKSPSetParametersEW" : NULL;
856: PetscFunctionBegin;
857: PetscOptionsBegin(comm, prefix, "Eisenstat and Walker type forcing options", "KSP");
858: PetscCall(PetscOptionsInt("-ksp_ew_version", "Version 1, 2 or 3", api, kctx->version, &kctx->version, NULL));
859: PetscCall(PetscOptionsReal("-ksp_ew_rtol0", "0 <= rtol0 < 1", api, kctx->rtol_0, &kctx->rtol_0, NULL));
860: kctx->rtol_max = PetscMax(kctx->rtol_0, kctx->rtol_max);
861: PetscCall(PetscOptionsReal("-ksp_ew_rtolmax", "0 <= rtolmax < 1", api, kctx->rtol_max, &kctx->rtol_max, NULL));
862: PetscCall(PetscOptionsReal("-ksp_ew_gamma", "0 <= gamma <= 1", api, kctx->gamma, &kctx->gamma, NULL));
863: PetscCall(PetscOptionsReal("-ksp_ew_alpha", "1 < alpha <= 2", api, kctx->alpha, &kctx->alpha, NULL));
864: PetscCall(PetscOptionsReal("-ksp_ew_alpha2", "alpha2", NULL, kctx->alpha2, &kctx->alpha2, NULL));
865: PetscCall(PetscOptionsReal("-ksp_ew_threshold", "0 < threshold < 1", api, kctx->threshold, &kctx->threshold, NULL));
866: PetscCall(PetscOptionsReal("-ksp_ew_v4_p1", "p1", NULL, kctx->v4_p1, &kctx->v4_p1, NULL));
867: PetscCall(PetscOptionsReal("-ksp_ew_v4_p2", "p2", NULL, kctx->v4_p2, &kctx->v4_p2, NULL));
868: PetscCall(PetscOptionsReal("-ksp_ew_v4_p3", "p3", NULL, kctx->v4_p3, &kctx->v4_p3, NULL));
869: PetscCall(PetscOptionsReal("-ksp_ew_v4_m1", "Scaling when rk-1 in [p2,p3)", NULL, kctx->v4_m1, &kctx->v4_m1, NULL));
870: PetscCall(PetscOptionsReal("-ksp_ew_v4_m2", "Scaling when rk-1 in [p3,+infty)", NULL, kctx->v4_m2, &kctx->v4_m2, NULL));
871: PetscCall(PetscOptionsReal("-ksp_ew_v4_m3", "Threshold for successive rtol (0.1 in Eq.7)", NULL, kctx->v4_m3, &kctx->v4_m3, NULL));
872: PetscCall(PetscOptionsReal("-ksp_ew_v4_m4", "Adaptation scaling (0.5 in Eq.7)", NULL, kctx->v4_m4, &kctx->v4_m4, NULL));
873: PetscOptionsEnd();
874: PetscFunctionReturn(PETSC_SUCCESS);
875: }
877: /*@
878: SNESSetFromOptions - Sets various `SNES` and `KSP` parameters from user options.
880: Collective
882: Input Parameter:
883: . snes - the `SNES` context
885: Options Database Keys:
886: + -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, `SNESType` for complete list
887: . -snes_stol - convergence tolerance in terms of the norm
888: of the change in the solution between steps
889: . -snes_atol <abstol> - absolute tolerance of residual norm
890: . -snes_rtol <rtol> - relative decrease in tolerance norm from initial
891: . -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
892: . -snes_force_iteration <force> - force SNESSolve() to take at least one iteration
893: . -snes_max_it <max_it> - maximum number of iterations
894: . -snes_max_funcs <max_funcs> - maximum number of function evaluations
895: . -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
896: . -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
897: . -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
898: . -snes_lag_preconditioner_persists <true,false> - retains the -snes_lag_preconditioner information across multiple SNESSolve()
899: . -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
900: . -snes_lag_jacobian_persists <true,false> - retains the -snes_lag_jacobian information across multiple SNESSolve()
901: . -snes_tr_tol <trtol> - trust region tolerance
902: . -snes_convergence_test - <default,skip,correct_pressure> convergence test in nonlinear solver.
903: default `SNESConvergedDefault()`. skip `SNESConvergedSkip()` means continue iterating until max_it or some other criterion is reached, saving expense
904: of convergence test. correct_pressure S`NESConvergedCorrectPressure()` has special handling of a pressure null space.
905: . -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
906: . -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
907: . -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
908: . -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
909: . -snes_monitor_lg_residualnorm - plots residual norm at each iteration
910: . -snes_monitor_lg_range - plots residual norm at each iteration
911: . -snes_monitor_pause_final - Pauses all monitor drawing after the solver ends
912: . -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
913: . -snes_fd_color - use finite differences with coloring to compute Jacobian
914: . -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
915: . -snes_converged_reason - print the reason for convergence/divergence after each solve
916: . -npc_snes_type <type> - the SNES type to use as a nonlinear preconditioner
917: . -snes_test_jacobian <optional threshold> - compare the user provided Jacobian with one computed via finite differences to check for errors. If a threshold is given, display only those entries whose difference is greater than the threshold.
918: - -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference between them to help users detect the location of errors in the user provided Jacobian.
920: Options Database Keys for Eisenstat-Walker method:
921: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
922: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
923: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
924: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
925: . -snes_ksp_ew_gamma <gamma> - Sets gamma
926: . -snes_ksp_ew_alpha <alpha> - Sets alpha
927: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
928: - -snes_ksp_ew_threshold <threshold> - Sets threshold
930: Level: beginner
932: Notes:
933: To see all options, run your program with the -help option or consult the users manual
935: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix free, and computing explicitly with
936: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
938: .seealso: [](chapter_snes), `SNESType`, `SNESSetOptionsPrefix()`, `SNESResetFromOptions()`, `SNES`, `SNESCreate()`
939: @*/
940: PetscErrorCode SNESSetFromOptions(SNES snes)
941: {
942: PetscBool flg, pcset, persist, set;
943: PetscInt i, indx, lag, grids;
944: const char *deft = SNESNEWTONLS;
945: const char *convtests[] = {"default", "skip", "correct_pressure"};
946: SNESKSPEW *kctx = NULL;
947: char type[256], monfilename[PETSC_MAX_PATH_LEN], ewprefix[256];
948: PCSide pcside;
949: const char *optionsprefix;
951: PetscFunctionBegin;
953: PetscCall(SNESRegisterAll());
954: PetscObjectOptionsBegin((PetscObject)snes);
955: if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
956: PetscCall(PetscOptionsFList("-snes_type", "Nonlinear solver method", "SNESSetType", SNESList, deft, type, 256, &flg));
957: if (flg) {
958: PetscCall(SNESSetType(snes, type));
959: } else if (!((PetscObject)snes)->type_name) {
960: PetscCall(SNESSetType(snes, deft));
961: }
962: PetscCall(PetscOptionsReal("-snes_stol", "Stop if step length less than", "SNESSetTolerances", snes->stol, &snes->stol, NULL));
963: PetscCall(PetscOptionsReal("-snes_atol", "Stop if function norm less than", "SNESSetTolerances", snes->abstol, &snes->abstol, NULL));
965: PetscCall(PetscOptionsReal("-snes_rtol", "Stop if decrease in function norm less than", "SNESSetTolerances", snes->rtol, &snes->rtol, NULL));
966: PetscCall(PetscOptionsReal("-snes_divergence_tolerance", "Stop if residual norm increases by this factor", "SNESSetDivergenceTolerance", snes->divtol, &snes->divtol, NULL));
967: PetscCall(PetscOptionsInt("-snes_max_it", "Maximum iterations", "SNESSetTolerances", snes->max_its, &snes->max_its, NULL));
968: PetscCall(PetscOptionsInt("-snes_max_funcs", "Maximum function evaluations", "SNESSetTolerances", snes->max_funcs, &snes->max_funcs, NULL));
969: PetscCall(PetscOptionsInt("-snes_max_fail", "Maximum nonlinear step failures", "SNESSetMaxNonlinearStepFailures", snes->maxFailures, &snes->maxFailures, NULL));
970: PetscCall(PetscOptionsInt("-snes_max_linear_solve_fail", "Maximum failures in linear solves allowed", "SNESSetMaxLinearSolveFailures", snes->maxLinearSolveFailures, &snes->maxLinearSolveFailures, NULL));
971: PetscCall(PetscOptionsBool("-snes_error_if_not_converged", "Generate error if solver does not converge", "SNESSetErrorIfNotConverged", snes->errorifnotconverged, &snes->errorifnotconverged, NULL));
972: PetscCall(PetscOptionsBool("-snes_force_iteration", "Force SNESSolve() to take at least one iteration", "SNESSetForceIteration", snes->forceiteration, &snes->forceiteration, NULL));
973: PetscCall(PetscOptionsBool("-snes_check_jacobian_domain_error", "Check Jacobian domain error after Jacobian evaluation", "SNESCheckJacobianDomainError", snes->checkjacdomainerror, &snes->checkjacdomainerror, NULL));
975: PetscCall(PetscOptionsInt("-snes_lag_preconditioner", "How often to rebuild preconditioner", "SNESSetLagPreconditioner", snes->lagpreconditioner, &lag, &flg));
976: if (flg) {
977: PetscCheck(lag != -1, PetscObjectComm((PetscObject)snes), PETSC_ERR_USER, "Cannot set the lag to -1 from the command line since the preconditioner must be built as least once, perhaps you mean -2");
978: PetscCall(SNESSetLagPreconditioner(snes, lag));
979: }
980: PetscCall(PetscOptionsBool("-snes_lag_preconditioner_persists", "Preconditioner lagging through multiple SNES solves", "SNESSetLagPreconditionerPersists", snes->lagjac_persist, &persist, &flg));
981: if (flg) PetscCall(SNESSetLagPreconditionerPersists(snes, persist));
982: PetscCall(PetscOptionsInt("-snes_lag_jacobian", "How often to rebuild Jacobian", "SNESSetLagJacobian", snes->lagjacobian, &lag, &flg));
983: if (flg) {
984: PetscCheck(lag != -1, PetscObjectComm((PetscObject)snes), PETSC_ERR_USER, "Cannot set the lag to -1 from the command line since the Jacobian must be built as least once, perhaps you mean -2");
985: PetscCall(SNESSetLagJacobian(snes, lag));
986: }
987: PetscCall(PetscOptionsBool("-snes_lag_jacobian_persists", "Jacobian lagging through multiple SNES solves", "SNESSetLagJacobianPersists", snes->lagjac_persist, &persist, &flg));
988: if (flg) PetscCall(SNESSetLagJacobianPersists(snes, persist));
990: PetscCall(PetscOptionsInt("-snes_grid_sequence", "Use grid sequencing to generate initial guess", "SNESSetGridSequence", snes->gridsequence, &grids, &flg));
991: if (flg) PetscCall(SNESSetGridSequence(snes, grids));
993: PetscCall(PetscOptionsEList("-snes_convergence_test", "Convergence test", "SNESSetConvergenceTest", convtests, sizeof(convtests) / sizeof(char *), "default", &indx, &flg));
994: if (flg) {
995: switch (indx) {
996: case 0:
997: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedDefault, NULL, NULL));
998: break;
999: case 1:
1000: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedSkip, NULL, NULL));
1001: break;
1002: case 2:
1003: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedCorrectPressure, NULL, NULL));
1004: break;
1005: }
1006: }
1008: PetscCall(PetscOptionsEList("-snes_norm_schedule", "SNES Norm schedule", "SNESSetNormSchedule", SNESNormSchedules, 5, "function", &indx, &flg));
1009: if (flg) PetscCall(SNESSetNormSchedule(snes, (SNESNormSchedule)indx));
1011: PetscCall(PetscOptionsEList("-snes_function_type", "SNES Norm schedule", "SNESSetFunctionType", SNESFunctionTypes, 2, "unpreconditioned", &indx, &flg));
1012: if (flg) PetscCall(SNESSetFunctionType(snes, (SNESFunctionType)indx));
1014: kctx = (SNESKSPEW *)snes->kspconvctx;
1016: PetscCall(PetscOptionsBool("-snes_ksp_ew", "Use Eisentat-Walker linear system convergence test", "SNESKSPSetUseEW", snes->ksp_ewconv, &snes->ksp_ewconv, NULL));
1018: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1019: PetscCall(PetscSNPrintf(ewprefix, sizeof(ewprefix), "%s%s", optionsprefix ? optionsprefix : "", "snes_"));
1020: PetscCall(SNESEWSetFromOptions_Private(kctx, PETSC_TRUE, PetscObjectComm((PetscObject)snes), ewprefix));
1022: flg = PETSC_FALSE;
1023: PetscCall(PetscOptionsBool("-snes_monitor_cancel", "Remove all monitors", "SNESMonitorCancel", flg, &flg, &set));
1024: if (set && flg) PetscCall(SNESMonitorCancel(snes));
1026: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor", "Monitor norm of function", "SNESMonitorDefault", SNESMonitorDefault, SNESMonitorDefaultSetUp));
1027: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_short", "Monitor norm of function with fewer digits", "SNESMonitorDefaultShort", SNESMonitorDefaultShort, NULL));
1028: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_range", "Monitor range of elements of function", "SNESMonitorRange", SNESMonitorRange, NULL));
1030: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_ratio", "Monitor ratios of the norm of function for consecutive steps", "SNESMonitorRatio", SNESMonitorRatio, SNESMonitorRatioSetUp));
1031: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_field", "Monitor norm of function (split into fields)", "SNESMonitorDefaultField", SNESMonitorDefaultField, NULL));
1032: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution", "View solution at each iteration", "SNESMonitorSolution", SNESMonitorSolution, NULL));
1033: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution_update", "View correction at each iteration", "SNESMonitorSolutionUpdate", SNESMonitorSolutionUpdate, NULL));
1034: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_residual", "View residual at each iteration", "SNESMonitorResidual", SNESMonitorResidual, NULL));
1035: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_jacupdate_spectrum", "Print the change in the spectrum of the Jacobian", "SNESMonitorJacUpdateSpectrum", SNESMonitorJacUpdateSpectrum, NULL));
1036: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_fields", "Monitor norm of function per field", "SNESMonitorSet", SNESMonitorFields, NULL));
1037: PetscCall(PetscOptionsBool("-snes_monitor_pause_final", "Pauses all draw monitors at the final iterate", "SNESMonitorPauseFinal_Internal", PETSC_FALSE, &snes->pauseFinal, NULL));
1039: PetscCall(PetscOptionsString("-snes_monitor_python", "Use Python function", "SNESMonitorSet", NULL, monfilename, sizeof(monfilename), &flg));
1040: if (flg) PetscCall(PetscPythonMonitorSet((PetscObject)snes, monfilename));
1042: flg = PETSC_FALSE;
1043: PetscCall(PetscOptionsBool("-snes_monitor_lg_range", "Plot function range at each iteration", "SNESMonitorLGRange", flg, &flg, NULL));
1044: if (flg) {
1045: PetscViewer ctx;
1047: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, NULL, PETSC_DECIDE, PETSC_DECIDE, 400, 300, &ctx));
1048: PetscCall(SNESMonitorSet(snes, SNESMonitorLGRange, ctx, (PetscErrorCode(*)(void **))PetscViewerDestroy));
1049: }
1051: flg = PETSC_FALSE;
1052: PetscCall(PetscOptionsBool("-snes_converged_reason_view_cancel", "Remove all converged reason viewers", "SNESConvergedReasonViewCancel", flg, &flg, &set));
1053: if (set && flg) PetscCall(SNESConvergedReasonViewCancel(snes));
1055: flg = PETSC_FALSE;
1056: PetscCall(PetscOptionsBool("-snes_fd", "Use finite differences (slow) to compute Jacobian", "SNESComputeJacobianDefault", flg, &flg, NULL));
1057: if (flg) {
1058: void *functx;
1059: DM dm;
1060: PetscCall(SNESGetDM(snes, &dm));
1061: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1062: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
1063: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefault, functx));
1064: PetscCall(PetscInfo(snes, "Setting default finite difference Jacobian matrix\n"));
1065: }
1067: flg = PETSC_FALSE;
1068: PetscCall(PetscOptionsBool("-snes_fd_function", "Use finite differences (slow) to compute function from user objective", "SNESObjectiveComputeFunctionDefaultFD", flg, &flg, NULL));
1069: if (flg) PetscCall(SNESSetFunction(snes, NULL, SNESObjectiveComputeFunctionDefaultFD, NULL));
1071: flg = PETSC_FALSE;
1072: PetscCall(PetscOptionsBool("-snes_fd_color", "Use finite differences with coloring to compute Jacobian", "SNESComputeJacobianDefaultColor", flg, &flg, NULL));
1073: if (flg) {
1074: DM dm;
1075: PetscCall(SNESGetDM(snes, &dm));
1076: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1077: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefaultColor, NULL));
1078: PetscCall(PetscInfo(snes, "Setting default finite difference coloring Jacobian matrix\n"));
1079: }
1081: flg = PETSC_FALSE;
1082: PetscCall(PetscOptionsBool("-snes_mf_operator", "Use a Matrix-Free Jacobian with user-provided preconditioner matrix", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf_operator, &flg));
1083: if (flg && snes->mf_operator) {
1084: snes->mf_operator = PETSC_TRUE;
1085: snes->mf = PETSC_TRUE;
1086: }
1087: flg = PETSC_FALSE;
1088: PetscCall(PetscOptionsBool("-snes_mf", "Use a Matrix-Free Jacobian with no preconditioner matrix", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf, &flg));
1089: if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1090: PetscCall(PetscOptionsInt("-snes_mf_version", "Matrix-Free routines version 1 or 2", "None", snes->mf_version, &snes->mf_version, NULL));
1092: flg = PETSC_FALSE;
1093: PetscCall(SNESGetNPCSide(snes, &pcside));
1094: PetscCall(PetscOptionsEnum("-snes_npc_side", "SNES nonlinear preconditioner side", "SNESSetNPCSide", PCSides, (PetscEnum)pcside, (PetscEnum *)&pcside, &flg));
1095: if (flg) PetscCall(SNESSetNPCSide(snes, pcside));
1097: #if defined(PETSC_HAVE_SAWS)
1098: /*
1099: Publish convergence information using SAWs
1100: */
1101: flg = PETSC_FALSE;
1102: PetscCall(PetscOptionsBool("-snes_monitor_saws", "Publish SNES progress using SAWs", "SNESMonitorSet", flg, &flg, NULL));
1103: if (flg) {
1104: void *ctx;
1105: PetscCall(SNESMonitorSAWsCreate(snes, &ctx));
1106: PetscCall(SNESMonitorSet(snes, SNESMonitorSAWs, ctx, SNESMonitorSAWsDestroy));
1107: }
1108: #endif
1109: #if defined(PETSC_HAVE_SAWS)
1110: {
1111: PetscBool set;
1112: flg = PETSC_FALSE;
1113: PetscCall(PetscOptionsBool("-snes_saws_block", "Block for SAWs at end of SNESSolve", "PetscObjectSAWsBlock", ((PetscObject)snes)->amspublishblock, &flg, &set));
1114: if (set) PetscCall(PetscObjectSAWsSetBlock((PetscObject)snes, flg));
1115: }
1116: #endif
1118: for (i = 0; i < numberofsetfromoptions; i++) PetscCall((*othersetfromoptions[i])(snes));
1120: PetscTryTypeMethod(snes, setfromoptions, PetscOptionsObject);
1122: /* process any options handlers added with PetscObjectAddOptionsHandler() */
1123: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)snes, PetscOptionsObject));
1124: PetscOptionsEnd();
1126: if (snes->linesearch) {
1127: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
1128: PetscCall(SNESLineSearchSetFromOptions(snes->linesearch));
1129: }
1131: if (snes->usesksp) {
1132: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
1133: PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre));
1134: PetscCall(KSPSetFromOptions(snes->ksp));
1135: }
1137: /* if user has set the SNES NPC type via options database, create it. */
1138: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1139: PetscCall(PetscOptionsHasName(((PetscObject)snes)->options, optionsprefix, "-npc_snes_type", &pcset));
1140: if (pcset && (!snes->npc)) PetscCall(SNESGetNPC(snes, &snes->npc));
1141: if (snes->npc) PetscCall(SNESSetFromOptions(snes->npc));
1142: snes->setfromoptionscalled++;
1143: PetscFunctionReturn(PETSC_SUCCESS);
1144: }
1146: /*@
1147: SNESResetFromOptions - Sets various `SNES` and `KSP` parameters from user options ONLY if the `SNESSetFromOptions()` was previously set from options
1149: Collective
1151: Input Parameter:
1152: . snes - the `SNES` context
1154: Level: beginner
1156: .seealso: [](chapter_snes), `SNES`, `SNESSetFromOptions()`, `SNESSetOptionsPrefix()`
1157: @*/
1158: PetscErrorCode SNESResetFromOptions(SNES snes)
1159: {
1160: PetscFunctionBegin;
1161: if (snes->setfromoptionscalled) PetscCall(SNESSetFromOptions(snes));
1162: PetscFunctionReturn(PETSC_SUCCESS);
1163: }
1165: /*@C
1166: SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1167: the nonlinear solvers.
1169: Logically Collective; No Fortran Support
1171: Input Parameters:
1172: + snes - the `SNES` context
1173: . compute - function to compute the context
1174: - destroy - function to destroy the context
1176: Level: intermediate
1178: Note:
1179: This routine is useful if you are performing grid sequencing or using `SNESFAS` and need the appropriate context generated for each level.
1181: Use `SNESSetApplicationContext()` to see the context immediately
1183: .seealso: [](chapter_snes), `SNESGetApplicationContext()`, `SNESSetComputeApplicationContext()`, `SNESSetApplicationContext()`
1184: @*/
1185: PetscErrorCode SNESSetComputeApplicationContext(SNES snes, PetscErrorCode (*compute)(SNES, void **), PetscErrorCode (*destroy)(void **))
1186: {
1187: PetscFunctionBegin;
1189: snes->ops->usercompute = compute;
1190: snes->ops->userdestroy = destroy;
1191: PetscFunctionReturn(PETSC_SUCCESS);
1192: }
1194: /*@
1195: SNESSetApplicationContext - Sets the optional user-defined context for the nonlinear solvers.
1197: Logically Collective
1199: Input Parameters:
1200: + snes - the `SNES` context
1201: - usrP - optional user context
1203: Level: intermediate
1205: Notes:
1206: Users can provide a context when constructing the `SNES` options and then access it inside their function, Jacobian, or other evaluation function
1207: with `SNESGetApplicationContext()`
1209: To provide a function that computes the context for you use `SNESSetComputeApplicationContext()`
1211: Fortran Note:
1212: You must write a Fortran interface definition for this
1213: function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.
1215: .seealso: [](chapter_snes), `SNES`, `SNESSetComputeApplicationContext()`, `SNESGetApplicationContext()`
1216: @*/
1217: PetscErrorCode SNESSetApplicationContext(SNES snes, void *usrP)
1218: {
1219: KSP ksp;
1221: PetscFunctionBegin;
1223: PetscCall(SNESGetKSP(snes, &ksp));
1224: PetscCall(KSPSetApplicationContext(ksp, usrP));
1225: snes->user = usrP;
1226: PetscFunctionReturn(PETSC_SUCCESS);
1227: }
1229: /*@
1230: SNESGetApplicationContext - Gets the user-defined context for the
1231: nonlinear solvers set with `SNESGetApplicationContext()` or with `SNESSetComputeApplicationContext()`
1233: Not Collective
1235: Input Parameter:
1236: . snes - `SNES` context
1238: Output Parameter:
1239: . usrP - user context
1241: Level: intermediate
1243: Fortran Note:
1244: You must write a Fortran interface definition for this
1245: function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.
1247: .seealso: [](chapter_snes), `SNESSetApplicationContext()`
1248: @*/
1249: PetscErrorCode SNESGetApplicationContext(SNES snes, void *usrP)
1250: {
1251: PetscFunctionBegin;
1253: *(void **)usrP = snes->user;
1254: PetscFunctionReturn(PETSC_SUCCESS);
1255: }
1257: /*@
1258: SNESSetUseMatrixFree - indicates that `SNES` should use matrix free finite difference matrix vector products to apply the Jacobian.
1260: Logically Collective
1262: Input Parameters:
1263: + snes - `SNES` context
1264: . mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1265: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored. With
1266: this option no matrix element based preconditioners can be used in the linear solve since the matrix won't be explicitly available
1268: Options Database Keys:
1269: + -snes_mf_operator - use matrix free only for the mat operator
1270: . -snes_mf - use matrix-free for both the mat and pmat operator
1271: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1272: - -snes_fd - compute the Jacobian via finite differences (slow)
1274: Level: intermediate
1276: Note:
1277: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free, and computing explicitly with
1278: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
1280: .seealso: [](chapter_snes), `SNES`, `SNESGetUseMatrixFree()`, `MatCreateSNESMF()`, `SNESComputeJacobianDefaultColor()`
1281: @*/
1282: PetscErrorCode SNESSetUseMatrixFree(SNES snes, PetscBool mf_operator, PetscBool mf)
1283: {
1284: PetscFunctionBegin;
1288: snes->mf = mf_operator ? PETSC_TRUE : mf;
1289: snes->mf_operator = mf_operator;
1290: PetscFunctionReturn(PETSC_SUCCESS);
1291: }
1293: /*@
1294: SNESGetUseMatrixFree - indicates if the `SNES` uses matrix-free finite difference matrix vector products to apply the Jacobian.
1296: Not Collective, but the resulting flags will be the same on all MPI ranks
1298: Input Parameter:
1299: . snes - `SNES` context
1301: Output Parameters:
1302: + mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1303: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored
1305: Level: intermediate
1307: .seealso: [](chapter_snes), `SNES`, `SNESSetUseMatrixFree()`, `MatCreateSNESMF()`
1308: @*/
1309: PetscErrorCode SNESGetUseMatrixFree(SNES snes, PetscBool *mf_operator, PetscBool *mf)
1310: {
1311: PetscFunctionBegin;
1313: if (mf) *mf = snes->mf;
1314: if (mf_operator) *mf_operator = snes->mf_operator;
1315: PetscFunctionReturn(PETSC_SUCCESS);
1316: }
1318: /*@
1319: SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1320: at this time.
1322: Not Collective
1324: Input Parameter:
1325: . snes - `SNES` context
1327: Output Parameter:
1328: . iter - iteration number
1330: Level: intermediate
1332: Notes:
1333: For example, during the computation of iteration 2 this would return 1.
1335: This is useful for using lagged Jacobians (where one does not recompute the
1336: Jacobian at each `SNES` iteration). For example, the code
1337: .vb
1338: ierr = SNESGetIterationNumber(snes,&it);
1339: if (!(it % 2)) {
1340: [compute Jacobian here]
1341: }
1342: .ve
1343: can be used in your function that computes the Jacobian to cause the Jacobian to be
1344: recomputed every second `SNES` iteration. See also `SNESSetLagJacobian()`
1346: After the `SNES` solve is complete this will return the number of nonlinear iterations used.
1348: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESSetLagJacobian()`, `SNESGetLinearSolveIterations()`
1349: @*/
1350: PetscErrorCode SNESGetIterationNumber(SNES snes, PetscInt *iter)
1351: {
1352: PetscFunctionBegin;
1355: *iter = snes->iter;
1356: PetscFunctionReturn(PETSC_SUCCESS);
1357: }
1359: /*@
1360: SNESSetIterationNumber - Sets the current iteration number.
1362: Not Collective
1364: Input Parameters:
1365: + snes - `SNES` context
1366: - iter - iteration number
1368: Level: developer
1370: .seealso: [](chapter_snes), `SNESGetLinearSolveIterations()`
1371: @*/
1372: PetscErrorCode SNESSetIterationNumber(SNES snes, PetscInt iter)
1373: {
1374: PetscFunctionBegin;
1376: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
1377: snes->iter = iter;
1378: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
1379: PetscFunctionReturn(PETSC_SUCCESS);
1380: }
1382: /*@
1383: SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1384: attempted by the nonlinear solver.
1386: Not Collective
1388: Input Parameter:
1389: . snes - `SNES` context
1391: Output Parameter:
1392: . nfails - number of unsuccessful steps attempted
1394: Level: intermediate
1396: Note:
1397: This counter is reset to zero for each successive call to `SNESSolve()`.
1399: .seealso: [](chapter_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1400: `SNESSetMaxNonlinearStepFailures()`, `SNESGetMaxNonlinearStepFailures()`
1401: @*/
1402: PetscErrorCode SNESGetNonlinearStepFailures(SNES snes, PetscInt *nfails)
1403: {
1404: PetscFunctionBegin;
1407: *nfails = snes->numFailures;
1408: PetscFunctionReturn(PETSC_SUCCESS);
1409: }
1411: /*@
1412: SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1413: attempted by the nonlinear solver before it gives up and generates an error
1415: Not Collective
1417: Input Parameters:
1418: + snes - `SNES` context
1419: - maxFails - maximum of unsuccessful steps
1421: Level: intermediate
1423: .seealso: [](chapter_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1424: `SNESGetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1425: @*/
1426: PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1427: {
1428: PetscFunctionBegin;
1430: snes->maxFailures = maxFails;
1431: PetscFunctionReturn(PETSC_SUCCESS);
1432: }
1434: /*@
1435: SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1436: attempted by the nonlinear solver before it gives up and generates an error
1438: Not Collective
1440: Input Parameter:
1441: . snes - `SNES` context
1443: Output Parameter:
1444: . maxFails - maximum of unsuccessful steps
1446: Level: intermediate
1448: .seealso: [](chapter_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1449: `SNESSetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1450: @*/
1451: PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1452: {
1453: PetscFunctionBegin;
1456: *maxFails = snes->maxFailures;
1457: PetscFunctionReturn(PETSC_SUCCESS);
1458: }
1460: /*@
1461: SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1462: done by the `SNES` object
1464: Not Collective
1466: Input Parameter:
1467: . snes - `SNES` context
1469: Output Parameter:
1470: . nfuncs - number of evaluations
1472: Level: intermediate
1474: Note:
1475: Reset every time `SNESSolve()` is called unless `SNESSetCountersReset()` is used.
1477: .seealso: [](chapter_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`, `SNESSetCountersReset()`
1478: @*/
1479: PetscErrorCode SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1480: {
1481: PetscFunctionBegin;
1484: *nfuncs = snes->nfuncs;
1485: PetscFunctionReturn(PETSC_SUCCESS);
1486: }
1488: /*@
1489: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1490: linear solvers.
1492: Not Collective
1494: Input Parameter:
1495: . snes - `SNES` context
1497: Output Parameter:
1498: . nfails - number of failed solves
1500: Options Database Key:
1501: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1503: Level: intermediate
1505: Note:
1506: This counter is reset to zero for each successive call to `SNESSolve()`.
1508: .seealso: [](chapter_snes), `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1509: @*/
1510: PetscErrorCode SNESGetLinearSolveFailures(SNES snes, PetscInt *nfails)
1511: {
1512: PetscFunctionBegin;
1515: *nfails = snes->numLinearSolveFailures;
1516: PetscFunctionReturn(PETSC_SUCCESS);
1517: }
1519: /*@
1520: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1521: allowed before `SNES` returns with a diverged reason of `SNES_DIVERGED_LINEAR_SOLVE`
1523: Logically Collective
1525: Input Parameters:
1526: + snes - `SNES` context
1527: - maxFails - maximum allowed linear solve failures
1529: Options Database Key:
1530: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1532: Level: intermediate
1534: Note:
1535: By default this is 0; that is `SNES` returns on the first failed linear solve
1537: .seealso: [](chapter_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`
1538: @*/
1539: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1540: {
1541: PetscFunctionBegin;
1544: snes->maxLinearSolveFailures = maxFails;
1545: PetscFunctionReturn(PETSC_SUCCESS);
1546: }
1548: /*@
1549: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1550: are allowed before `SNES` returns as unsuccessful
1552: Not Collective
1554: Input Parameter:
1555: . snes - `SNES` context
1557: Output Parameter:
1558: . maxFails - maximum of unsuccessful solves allowed
1560: Level: intermediate
1562: Note:
1563: By default this is 1; that is `SNES` returns on the first failed linear solve
1565: .seealso: [](chapter_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`,
1566: @*/
1567: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1568: {
1569: PetscFunctionBegin;
1572: *maxFails = snes->maxLinearSolveFailures;
1573: PetscFunctionReturn(PETSC_SUCCESS);
1574: }
1576: /*@
1577: SNESGetLinearSolveIterations - Gets the total number of linear iterations
1578: used by the nonlinear solver.
1580: Not Collective
1582: Input Parameter:
1583: . snes - `SNES` context
1585: Output Parameter:
1586: . lits - number of linear iterations
1588: Level: intermediate
1590: Notes:
1591: This counter is reset to zero for each successive call to `SNESSolve()` unless `SNESSetCountersReset()` is used.
1593: If the linear solver fails inside the `SNESSolve()` the iterations for that call to the linear solver are not included. If you wish to count them
1594: then call `KSPGetIterationNumber()` after the failed solve.
1596: .seealso: [](chapter_snes), `SNES`, `SNESGetIterationNumber()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESSetCountersReset()`
1597: @*/
1598: PetscErrorCode SNESGetLinearSolveIterations(SNES snes, PetscInt *lits)
1599: {
1600: PetscFunctionBegin;
1603: *lits = snes->linear_its;
1604: PetscFunctionReturn(PETSC_SUCCESS);
1605: }
1607: /*@
1608: SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1609: are reset every time `SNESSolve()` is called.
1611: Logically Collective
1613: Input Parameters:
1614: + snes - `SNES` context
1615: - reset - whether to reset the counters or not, defaults to `PETSC_TRUE`
1617: Level: developer
1619: .seealso: [](chapter_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1620: @*/
1621: PetscErrorCode SNESSetCountersReset(SNES snes, PetscBool reset)
1622: {
1623: PetscFunctionBegin;
1626: snes->counters_reset = reset;
1627: PetscFunctionReturn(PETSC_SUCCESS);
1628: }
1630: /*@
1631: SNESSetKSP - Sets a `KSP` context for the `SNES` object to use
1633: Not Collective, but the `SNES` and `KSP` objects must live on the same MPI_Comm
1635: Input Parameters:
1636: + snes - the `SNES` context
1637: - ksp - the `KSP` context
1639: Level: developer
1641: Notes:
1642: The `SNES` object already has its `KSP` object, you can obtain with `SNESGetKSP()`
1643: so this routine is rarely needed.
1645: The `KSP` object that is already in the `SNES` object has its reference count
1646: decreased by one.
1648: .seealso: [](chapter_snes), `SNES`, `KSP`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
1649: @*/
1650: PetscErrorCode SNESSetKSP(SNES snes, KSP ksp)
1651: {
1652: PetscFunctionBegin;
1655: PetscCheckSameComm(snes, 1, ksp, 2);
1656: PetscCall(PetscObjectReference((PetscObject)ksp));
1657: if (snes->ksp) PetscCall(PetscObjectDereference((PetscObject)snes->ksp));
1658: snes->ksp = ksp;
1659: PetscFunctionReturn(PETSC_SUCCESS);
1660: }
1662: /*@
1663: SNESCreate - Creates a nonlinear solver context used to manage a set of nonlinear solves
1665: Collective
1667: Input Parameter:
1668: . comm - MPI communicator
1670: Output Parameter:
1671: . outsnes - the new `SNES` context
1673: Options Database Keys:
1674: + -snes_mf - Activates default matrix-free Jacobian-vector products, and no preconditioning matrix
1675: . -snes_mf_operator - Activates default matrix-free Jacobian-vector products, and a user-provided preconditioning matrix
1676: as set by `SNESSetJacobian()`
1677: . -snes_fd_coloring - uses a relative fast computation of the Jacobian using finite differences and a graph coloring
1678: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
1680: Level: beginner
1682: Developer Notes:
1683: `SNES` always creates a `KSP` object even though many `SNES` methods do not use it. This is
1684: unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1685: particular method does use `KSP` and regulates if the information about the `KSP` is printed
1686: in `SNESView()`.
1688: `TSSetFromOptions()` does call `SNESSetFromOptions()` which can lead to users being confused
1689: by help messages about meaningless `SNES` options.
1691: `SNES` always creates the snes->kspconvctx even though it is used by only one type. This should be fixed.
1693: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNES`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
1694: @*/
1695: PetscErrorCode SNESCreate(MPI_Comm comm, SNES *outsnes)
1696: {
1697: SNES snes;
1698: SNESKSPEW *kctx;
1700: PetscFunctionBegin;
1702: *outsnes = NULL;
1703: PetscCall(SNESInitializePackage());
1705: PetscCall(PetscHeaderCreate(snes, SNES_CLASSID, "SNES", "Nonlinear solver", "SNES", comm, SNESDestroy, SNESView));
1707: snes->ops->converged = SNESConvergedDefault;
1708: snes->usesksp = PETSC_TRUE;
1709: snes->tolerancesset = PETSC_FALSE;
1710: snes->max_its = 50;
1711: snes->max_funcs = 10000;
1712: snes->norm = 0.0;
1713: snes->xnorm = 0.0;
1714: snes->ynorm = 0.0;
1715: snes->normschedule = SNES_NORM_ALWAYS;
1716: snes->functype = SNES_FUNCTION_DEFAULT;
1717: snes->rtol = PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8;
1718: snes->ttol = 0.0;
1719: snes->abstol = PetscDefined(USE_REAL_SINGLE) ? 1.e-25 : 1.e-50;
1720: snes->stol = PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8;
1721: snes->deltatol = PetscDefined(USE_REAL_SINGLE) ? 1.e-6 : 1.e-12;
1722: snes->divtol = 1.e4;
1723: snes->rnorm0 = 0;
1724: snes->nfuncs = 0;
1725: snes->numFailures = 0;
1726: snes->maxFailures = 1;
1727: snes->linear_its = 0;
1728: snes->lagjacobian = 1;
1729: snes->jac_iter = 0;
1730: snes->lagjac_persist = PETSC_FALSE;
1731: snes->lagpreconditioner = 1;
1732: snes->pre_iter = 0;
1733: snes->lagpre_persist = PETSC_FALSE;
1734: snes->numbermonitors = 0;
1735: snes->numberreasonviews = 0;
1736: snes->data = NULL;
1737: snes->setupcalled = PETSC_FALSE;
1738: snes->ksp_ewconv = PETSC_FALSE;
1739: snes->nwork = 0;
1740: snes->work = NULL;
1741: snes->nvwork = 0;
1742: snes->vwork = NULL;
1743: snes->conv_hist_len = 0;
1744: snes->conv_hist_max = 0;
1745: snes->conv_hist = NULL;
1746: snes->conv_hist_its = NULL;
1747: snes->conv_hist_reset = PETSC_TRUE;
1748: snes->counters_reset = PETSC_TRUE;
1749: snes->vec_func_init_set = PETSC_FALSE;
1750: snes->reason = SNES_CONVERGED_ITERATING;
1751: snes->npcside = PC_RIGHT;
1752: snes->setfromoptionscalled = 0;
1754: snes->mf = PETSC_FALSE;
1755: snes->mf_operator = PETSC_FALSE;
1756: snes->mf_version = 1;
1758: snes->numLinearSolveFailures = 0;
1759: snes->maxLinearSolveFailures = 1;
1761: snes->vizerotolerance = 1.e-8;
1762: snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;
1764: /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1765: snes->alwayscomputesfinalresidual = PETSC_FALSE;
1767: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1768: PetscCall(PetscNew(&kctx));
1770: snes->kspconvctx = (void *)kctx;
1771: kctx->version = 2;
1772: kctx->rtol_0 = 0.3; /* Eisenstat and Walker suggest rtol_0=.5, but
1773: this was too large for some test cases */
1774: kctx->rtol_last = 0.0;
1775: kctx->rtol_max = 0.9;
1776: kctx->gamma = 1.0;
1777: kctx->alpha = 0.5 * (1.0 + PetscSqrtReal(5.0));
1778: kctx->alpha2 = kctx->alpha;
1779: kctx->threshold = 0.1;
1780: kctx->lresid_last = 0.0;
1781: kctx->norm_last = 0.0;
1783: kctx->rk_last = 0.0;
1784: kctx->rk_last_2 = 0.0;
1785: kctx->rtol_last_2 = 0.0;
1786: kctx->v4_p1 = 0.1;
1787: kctx->v4_p2 = 0.4;
1788: kctx->v4_p3 = 0.7;
1789: kctx->v4_m1 = 0.8;
1790: kctx->v4_m2 = 0.5;
1791: kctx->v4_m3 = 0.1;
1792: kctx->v4_m4 = 0.5;
1794: *outsnes = snes;
1795: PetscFunctionReturn(PETSC_SUCCESS);
1796: }
1798: /*MC
1799: SNESFunction - Functional form used to convey the nonlinear function to `SNES` in `SNESSetFunction()`
1801: Synopsis:
1802: #include "petscsnes.h"
1803: PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);
1805: Collective
1807: Input Parameters:
1808: + snes - the `SNES` context
1809: . x - state at which to evaluate residual
1810: - ctx - optional user-defined function context, passed in with `SNESSetFunction()`
1812: Output Parameter:
1813: . f - vector to put residual (function value)
1815: Level: intermediate
1817: .seealso: [](chapter_snes), `SNESSetFunction()`, `SNESGetFunction()`
1818: M*/
1820: /*@C
1821: SNESSetFunction - Sets the function evaluation routine and function
1822: vector for use by the `SNES` routines in solving systems of nonlinear
1823: equations.
1825: Logically Collective
1827: Input Parameters:
1828: + snes - the `SNES` context
1829: . r - vector to store function values, may be `NULL`
1830: . f - function evaluation routine; for calling sequence see `SNESFunction`
1831: - ctx - [optional] user-defined context for private data for the
1832: function evaluation routine (may be `NULL`)
1834: Level: beginner
1836: .seealso: [](chapter_snes), `SNES`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetPicard()`, `SNESFunction`
1837: @*/
1838: PetscErrorCode SNESSetFunction(SNES snes, Vec r, PetscErrorCode (*f)(SNES, Vec, Vec, void *), void *ctx)
1839: {
1840: DM dm;
1842: PetscFunctionBegin;
1844: if (r) {
1846: PetscCheckSameComm(snes, 1, r, 2);
1847: PetscCall(PetscObjectReference((PetscObject)r));
1848: PetscCall(VecDestroy(&snes->vec_func));
1849: snes->vec_func = r;
1850: }
1851: PetscCall(SNESGetDM(snes, &dm));
1852: PetscCall(DMSNESSetFunction(dm, f, ctx));
1853: if (f == SNESPicardComputeFunction) PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
1854: PetscFunctionReturn(PETSC_SUCCESS);
1855: }
1857: /*@C
1858: SNESSetInitialFunction - Sets the function vector to be used as the
1859: initial function value at the initialization of the method. In some
1860: instances, the user has precomputed the function before calling
1861: `SNESSolve()`. This function allows one to avoid a redundant call
1862: to `SNESComputeFunction()` in that case.
1864: Logically Collective
1866: Input Parameters:
1867: + snes - the `SNES` context
1868: - f - vector to store function value
1870: Level: developer
1872: Notes:
1873: This should not be modified during the solution procedure.
1875: This is used extensively in the `SNESFAS` hierarchy and in nonlinear preconditioning.
1877: .seealso: [](chapter_snes), `SNES`, `SNESFAS`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetInitialFunctionNorm()`
1878: @*/
1879: PetscErrorCode SNESSetInitialFunction(SNES snes, Vec f)
1880: {
1881: Vec vec_func;
1883: PetscFunctionBegin;
1886: PetscCheckSameComm(snes, 1, f, 2);
1887: if (snes->npcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1888: snes->vec_func_init_set = PETSC_FALSE;
1889: PetscFunctionReturn(PETSC_SUCCESS);
1890: }
1891: PetscCall(SNESGetFunction(snes, &vec_func, NULL, NULL));
1892: PetscCall(VecCopy(f, vec_func));
1894: snes->vec_func_init_set = PETSC_TRUE;
1895: PetscFunctionReturn(PETSC_SUCCESS);
1896: }
1898: /*@
1899: SNESSetNormSchedule - Sets the `SNESNormSchedule` used in convergence and monitoring
1900: of the `SNES` method, when norms are computed in the solving process
1902: Logically Collective
1904: Input Parameters:
1905: + snes - the `SNES` context
1906: - normschedule - the frequency of norm computation
1908: Options Database Key:
1909: . -snes_norm_schedule <none, always, initialonly, finalonly, initialfinalonly> - set the schedule
1911: Level: advanced
1913: Notes:
1914: Only certain `SNES` methods support certain `SNESNormSchedules`. Most require evaluation
1915: of the nonlinear function and the taking of its norm at every iteration to
1916: even ensure convergence at all. However, methods such as custom Gauss-Seidel methods
1917: `SNESNGS` and the like do not require the norm of the function to be computed, and therefore
1918: may either be monitored for convergence or not. As these are often used as nonlinear
1919: preconditioners, monitoring the norm of their error is not a useful enterprise within
1920: their solution.
1922: .seealso: [](chapter_snes), `SNESNormSchedule`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
1923: @*/
1924: PetscErrorCode SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1925: {
1926: PetscFunctionBegin;
1928: snes->normschedule = normschedule;
1929: PetscFunctionReturn(PETSC_SUCCESS);
1930: }
1932: /*@
1933: SNESGetNormSchedule - Gets the `SNESNormSchedule` used in convergence and monitoring
1934: of the `SNES` method.
1936: Logically Collective
1938: Input Parameters:
1939: + snes - the `SNES` context
1940: - normschedule - the type of the norm used
1942: Level: advanced
1944: .seealso: [](chapter_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
1945: @*/
1946: PetscErrorCode SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1947: {
1948: PetscFunctionBegin;
1950: *normschedule = snes->normschedule;
1951: PetscFunctionReturn(PETSC_SUCCESS);
1952: }
1954: /*@
1955: SNESSetFunctionNorm - Sets the last computed residual norm.
1957: Logically Collective
1959: Input Parameters:
1960: + snes - the `SNES` context
1961: - norm - the value of the norm
1963: Level: developer
1965: .seealso: [](chapter_snes), `SNES`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
1966: @*/
1967: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
1968: {
1969: PetscFunctionBegin;
1971: snes->norm = norm;
1972: PetscFunctionReturn(PETSC_SUCCESS);
1973: }
1975: /*@
1976: SNESGetFunctionNorm - Gets the last computed norm of the residual
1978: Not Collective
1980: Input Parameter:
1981: . snes - the `SNES` context
1983: Output Parameter:
1984: . norm - the last computed residual norm
1986: Level: developer
1988: .seealso: [](chapter_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
1989: @*/
1990: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
1991: {
1992: PetscFunctionBegin;
1995: *norm = snes->norm;
1996: PetscFunctionReturn(PETSC_SUCCESS);
1997: }
1999: /*@
2000: SNESGetUpdateNorm - Gets the last computed norm of the solution update
2002: Not Collective
2004: Input Parameter:
2005: . snes - the `SNES` context
2007: Output Parameter:
2008: . ynorm - the last computed update norm
2010: Level: developer
2012: Note:
2013: The new solution is the current solution plus the update, so this norm is an indication of the size of the update
2015: .seealso: [](chapter_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`
2016: @*/
2017: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2018: {
2019: PetscFunctionBegin;
2022: *ynorm = snes->ynorm;
2023: PetscFunctionReturn(PETSC_SUCCESS);
2024: }
2026: /*@
2027: SNESGetSolutionNorm - Gets the last computed norm of the solution
2029: Not Collective
2031: Input Parameter:
2032: . snes - the `SNES` context
2034: Output Parameter:
2035: . xnorm - the last computed solution norm
2037: Level: developer
2039: .seealso: [](chapter_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`, `SNESGetUpdateNorm()`
2040: @*/
2041: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2042: {
2043: PetscFunctionBegin;
2046: *xnorm = snes->xnorm;
2047: PetscFunctionReturn(PETSC_SUCCESS);
2048: }
2050: /*@C
2051: SNESSetFunctionType - Sets the `SNESFunctionType`
2052: of the `SNES` method.
2054: Logically Collective
2056: Input Parameters:
2057: + snes - the `SNES` context
2058: - type - the function type
2060: Level: developer
2062: Notes:
2063: Possible values of the function type
2064: + `SNES_FUNCTION_DEFAULT` - the default for the given `SNESType`
2065: . `SNES_FUNCTION_UNPRECONDITIONED` - an unpreconditioned function evaluation (this is the function provided with `SNESSetFunction()`
2066: - `SNES_FUNCTION_PRECONDITIONED` - a transformation of the function provided with `SNESSetFunction()`
2068: Different `SNESType`s use this value in different ways
2070: .seealso: [](chapter_snes), `SNES`, `SNESFunctionType`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2071: @*/
2072: PetscErrorCode SNESSetFunctionType(SNES snes, SNESFunctionType type)
2073: {
2074: PetscFunctionBegin;
2076: snes->functype = type;
2077: PetscFunctionReturn(PETSC_SUCCESS);
2078: }
2080: /*@C
2081: SNESGetFunctionType - Gets the `SNESFunctionType` used in convergence and monitoring set with `SNESSetFunctionType()`
2082: of the SNES method.
2084: Logically Collective
2086: Input Parameters:
2087: + snes - the `SNES` context
2088: - type - the type of the function evaluation, see `SNESSetFunctionType()`
2090: Level: advanced
2092: .seealso: [](chapter_snes), `SNESSetFunctionType()`, `SNESFunctionType`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2093: @*/
2094: PetscErrorCode SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2095: {
2096: PetscFunctionBegin;
2098: *type = snes->functype;
2099: PetscFunctionReturn(PETSC_SUCCESS);
2100: }
2102: /*MC
2103: SNESNGSFunction - function used to apply a Gauss-Seidel sweep on the nonlinear function
2105: Synopsis:
2106: #include <petscsnes.h>
2107: $ SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);
2109: Collective
2111: Input Parameters:
2112: + X - solution vector
2113: . B - RHS vector
2114: - ctx - optional user-defined Gauss-Seidel context
2116: Output Parameter:
2117: . X - solution vector
2119: Level: intermediate
2121: .seealso: [](chapter_snes), `SNESNGS`, `SNESSetNGS()`, `SNESGetNGS()`
2122: M*/
2124: /*@C
2125: SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2126: use with composed nonlinear solvers.
2128: Input Parameters:
2129: + snes - the `SNES` context
2130: . f - function evaluation routine to apply Gauss-Seidel see `SNESNGSFunction`
2131: - ctx - [optional] user-defined context for private data for the
2132: smoother evaluation routine (may be `NULL`)
2134: Calling sequence of `f`:
2135: $ PetscErrorCode f(SNES snes, Vec X, Vec B, void *ctx)
2136: + snes - the `SNES` context
2137: . X - the current solution
2138: . B - the right hand side vector (which may be `NULL`)
2139: - ctx - a user provided context
2141: Level: intermediate
2143: Note:
2144: The `SNESNGS` routines are used by the composed nonlinear solver to generate
2145: a problem appropriate update to the solution, particularly `SNESFAS`.
2147: .seealso: [](chapter_snes), `SNESGetNGS()`, `SNESNGSFunction`, `SNESNCG`, `SNESGetFunction()`, `SNESComputeNGS()`
2148: @*/
2149: PetscErrorCode SNESSetNGS(SNES snes, PetscErrorCode (*f)(SNES, Vec, Vec, void *), void *ctx)
2150: {
2151: DM dm;
2153: PetscFunctionBegin;
2155: PetscCall(SNESGetDM(snes, &dm));
2156: PetscCall(DMSNESSetNGS(dm, f, ctx));
2157: PetscFunctionReturn(PETSC_SUCCESS);
2158: }
2160: /*
2161: This is used for -snes_mf_operator; it uses a duplicate of snes->jacobian_pre because snes->jacobian_pre cannot be
2162: changed during the KSPSolve()
2163: */
2164: PetscErrorCode SNESPicardComputeMFFunction(SNES snes, Vec x, Vec f, void *ctx)
2165: {
2166: DM dm;
2167: DMSNES sdm;
2169: PetscFunctionBegin;
2170: PetscCall(SNESGetDM(snes, &dm));
2171: PetscCall(DMGetDMSNES(dm, &sdm));
2172: /* A(x)*x - b(x) */
2173: if (sdm->ops->computepfunction) {
2174: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2175: PetscCall(VecScale(f, -1.0));
2176: /* Cannot share nonzero pattern because of the possible use of SNESComputeJacobianDefault() */
2177: if (!snes->picard) PetscCall(MatDuplicate(snes->jacobian_pre, MAT_DO_NOT_COPY_VALUES, &snes->picard));
2178: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2179: PetscCall(MatMultAdd(snes->picard, x, f, f));
2180: } else {
2181: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2182: PetscCall(MatMult(snes->picard, x, f));
2183: }
2184: PetscFunctionReturn(PETSC_SUCCESS);
2185: }
2187: PetscErrorCode SNESPicardComputeFunction(SNES snes, Vec x, Vec f, void *ctx)
2188: {
2189: DM dm;
2190: DMSNES sdm;
2192: PetscFunctionBegin;
2193: PetscCall(SNESGetDM(snes, &dm));
2194: PetscCall(DMGetDMSNES(dm, &sdm));
2195: /* A(x)*x - b(x) */
2196: if (sdm->ops->computepfunction) {
2197: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2198: PetscCall(VecScale(f, -1.0));
2199: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2200: PetscCall(MatMultAdd(snes->jacobian_pre, x, f, f));
2201: } else {
2202: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2203: PetscCall(MatMult(snes->jacobian_pre, x, f));
2204: }
2205: PetscFunctionReturn(PETSC_SUCCESS);
2206: }
2208: PetscErrorCode SNESPicardComputeJacobian(SNES snes, Vec x1, Mat J, Mat B, void *ctx)
2209: {
2210: PetscFunctionBegin;
2211: /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2212: /* must assembly if matrix-free to get the last SNES solution */
2213: PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
2214: PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
2215: PetscFunctionReturn(PETSC_SUCCESS);
2216: }
2218: /*@C
2219: SNESSetPicard - Use `SNES` to solve the system A(x) x = bp(x) + b via a Picard type iteration (Picard linearization)
2221: Logically Collective
2223: Input Parameters:
2224: + snes - the `SNES` context
2225: . r - vector to store function values, may be `NULL`
2226: . bp - function evaluation routine, may be `NULL`
2227: . Amat - matrix with which A(x) x - bp(x) - b is to be computed
2228: . Pmat - matrix from which preconditioner is computed (usually the same as `Amat`)
2229: . J - function to compute matrix values, for the calling sequence see `SNESJacobianFunction()`
2230: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
2232: Level: intermediate
2234: Notes:
2235: It is often better to provide the nonlinear function F() and some approximation to its Jacobian directly and use
2236: an approximate Newton solver. This interface is provided to allow porting/testing a previous Picard based code in PETSc before converting it to approximate Newton.
2238: One can call `SNESSetPicard()` or `SNESSetFunction()` (and possibly `SNESSetJacobian()`) but cannot call both
2240: Solves the equation A(x) x = bp(x) - b via the defect correction algorithm A(x^{n}) (x^{n+1} - x^{n}) = bp(x^{n}) + b - A(x^{n})x^{n}.
2241: When an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = bp(x^{n}) + b iteration.
2243: Run with `-snes_mf_operator` to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.
2245: We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2246: the direct Picard iteration A(x^n) x^{n+1} = bp(x^n) + b
2248: There is some controversity over the definition of a Picard iteration for nonlinear systems but almost everyone agrees that it involves a linear solve and some
2249: believe it is the iteration A(x^{n}) x^{n+1} = b(x^{n}) hence we use the name Picard. If anyone has an authoritative reference that defines the Picard iteration
2250: different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).
2252: When used with `-snes_mf_operator` this will run matrix-free Newton's method where the matrix-vector product is of the true Jacobian of A(x)x - bp(x) -b and
2253: A(x^{n}) is used to build the preconditioner
2255: When used with `-snes_fd` this will compute the true Jacobian (very slowly one column at at time) and thus represent Newton's method.
2257: When used with `-snes_fd_coloring` this will compute the Jacobian via coloring and thus represent a faster implementation of Newton's method. But the
2258: the nonzero structure of the Jacobian is, in general larger than that of the Picard matrix A so you must provide in A the needed nonzero structure for the correct
2259: coloring. When using `DMDA` this may mean creating the matrix A with `DMCreateMatrix()` using a wider stencil than strictly needed for A or with a `DMDA_STENCIL_BOX`.
2260: See the commment in src/snes/tutorials/ex15.c.
2262: .seealso: [](chapter_snes), `SNES`, `SNESGetFunction()`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESGetPicard()`, `SNESLineSearchPreCheckPicard()`, `SNESJacobianFunction`
2263: @*/
2264: PetscErrorCode SNESSetPicard(SNES snes, Vec r, PetscErrorCode (*bp)(SNES, Vec, Vec, void *), Mat Amat, Mat Pmat, PetscErrorCode (*J)(SNES, Vec, Mat, Mat, void *), void *ctx)
2265: {
2266: DM dm;
2268: PetscFunctionBegin;
2270: PetscCall(SNESGetDM(snes, &dm));
2271: PetscCall(DMSNESSetPicard(dm, bp, J, ctx));
2272: PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2273: PetscCall(SNESSetFunction(snes, r, SNESPicardComputeFunction, ctx));
2274: PetscCall(SNESSetJacobian(snes, Amat, Pmat, SNESPicardComputeJacobian, ctx));
2275: PetscFunctionReturn(PETSC_SUCCESS);
2276: }
2278: /*@C
2279: SNESGetPicard - Returns the context for the Picard iteration
2281: Not Collective, but `Vec` is parallel if `SNES` is parallel. Collective if `Vec` is requested, but has not been created yet.
2283: Input Parameter:
2284: . snes - the `SNES` context
2286: Output Parameters:
2287: + r - the function (or `NULL`)
2288: . f - the function (or `NULL`); for calling sequence see `SNESFunction`
2289: . Amat - the matrix used to defined the operation A(x) x - b(x) (or `NULL`)
2290: . Pmat - the matrix from which the preconditioner will be constructed (or `NULL`)
2291: . J - the function for matrix evaluation (or `NULL`); for calling sequence see `SNESJacobianFunction`
2292: - ctx - the function context (or `NULL`)
2294: Level: advanced
2296: .seealso: [](chapter_snes), `SNESSetFunction()`, `SNESSetPicard()`, `SNESGetFunction()`, `SNESGetJacobian()`, `SNESGetDM()`, `SNESFunction`, `SNESJacobianFunction`
2297: @*/
2298: PetscErrorCode SNESGetPicard(SNES snes, Vec *r, PetscErrorCode (**f)(SNES, Vec, Vec, void *), Mat *Amat, Mat *Pmat, PetscErrorCode (**J)(SNES, Vec, Mat, Mat, void *), void **ctx)
2299: {
2300: DM dm;
2302: PetscFunctionBegin;
2304: PetscCall(SNESGetFunction(snes, r, NULL, NULL));
2305: PetscCall(SNESGetJacobian(snes, Amat, Pmat, NULL, NULL));
2306: PetscCall(SNESGetDM(snes, &dm));
2307: PetscCall(DMSNESGetPicard(dm, f, J, ctx));
2308: PetscFunctionReturn(PETSC_SUCCESS);
2309: }
2311: /*@C
2312: SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the nonlinear problem
2314: Logically Collective
2316: Input Parameters:
2317: + snes - the `SNES` context
2318: . func - function evaluation routine
2319: - ctx - [optional] user-defined context for private data for the
2320: function evaluation routine (may be `NULL`)
2322: Calling sequence of `func`:
2323: $ PetscErrorCode func(SNES snes, Vec x, void *ctx);
2324: + snes - the `SNES` solver
2325: . x - vector to put initial guess
2326: - ctx - optional user-defined function context
2328: Level: intermediate
2330: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`
2331: @*/
2332: PetscErrorCode SNESSetComputeInitialGuess(SNES snes, PetscErrorCode (*func)(SNES, Vec, void *), void *ctx)
2333: {
2334: PetscFunctionBegin;
2336: if (func) snes->ops->computeinitialguess = func;
2337: if (ctx) snes->initialguessP = ctx;
2338: PetscFunctionReturn(PETSC_SUCCESS);
2339: }
2341: /*@C
2342: SNESGetRhs - Gets the vector for solving F(x) = `rhs`. If `rhs` is not set
2343: it assumes a zero right hand side.
2345: Logically Collective
2347: Input Parameter:
2348: . snes - the `SNES` context
2350: Output Parameter:
2351: . rhs - the right hand side vector or `NULL` if the right hand side vector is null
2353: Level: intermediate
2355: .seealso: [](chapter_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetFunction()`
2356: @*/
2357: PetscErrorCode SNESGetRhs(SNES snes, Vec *rhs)
2358: {
2359: PetscFunctionBegin;
2362: *rhs = snes->vec_rhs;
2363: PetscFunctionReturn(PETSC_SUCCESS);
2364: }
2366: /*@
2367: SNESComputeFunction - Calls the function that has been set with `SNESSetFunction()`.
2369: Collective
2371: Input Parameters:
2372: + snes - the `SNES` context
2373: - x - input vector
2375: Output Parameter:
2376: . y - function vector, as set by `SNESSetFunction()`
2378: Level: developer
2380: Note:
2381: `SNESComputeFunction()` is typically used within nonlinear solvers
2382: implementations, so users would not generally call this routine themselves.
2384: .seealso: [](chapter_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeMFFunction()`
2385: @*/
2386: PetscErrorCode SNESComputeFunction(SNES snes, Vec x, Vec y)
2387: {
2388: DM dm;
2389: DMSNES sdm;
2391: PetscFunctionBegin;
2395: PetscCheckSameComm(snes, 1, x, 2);
2396: PetscCheckSameComm(snes, 1, y, 3);
2397: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2399: PetscCall(SNESGetDM(snes, &dm));
2400: PetscCall(DMGetDMSNES(dm, &sdm));
2401: PetscCheck(sdm->ops->computefunction || snes->vec_rhs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2402: if (sdm->ops->computefunction) {
2403: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2404: PetscCall(VecLockReadPush(x));
2405: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2406: snes->domainerror = PETSC_FALSE;
2407: {
2408: void *ctx;
2409: PetscErrorCode (*computefunction)(SNES, Vec, Vec, void *);
2410: PetscCall(DMSNESGetFunction(dm, &computefunction, &ctx));
2411: PetscCallBack("SNES callback function", (*computefunction)(snes, x, y, ctx));
2412: }
2413: PetscCall(VecLockReadPop(x));
2414: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2415: } else /* if (snes->vec_rhs) */ {
2416: PetscCall(MatMult(snes->jacobian, x, y));
2417: }
2418: if (snes->vec_rhs) PetscCall(VecAXPY(y, -1.0, snes->vec_rhs));
2419: snes->nfuncs++;
2420: /*
2421: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2422: propagate the value to all processes
2423: */
2424: if (snes->domainerror) PetscCall(VecSetInf(y));
2425: PetscFunctionReturn(PETSC_SUCCESS);
2426: }
2428: /*@
2429: SNESComputeMFFunction - Calls the function that has been set with `SNESSetMFFunction()`.
2431: Collective
2433: Input Parameters:
2434: + snes - the `SNES` context
2435: - x - input vector
2437: Output Parameter:
2438: . y - function vector, as set by `SNESSetMFFunction()`
2440: Level: developer
2442: Notes:
2443: `SNESComputeMFFunction()` is used within the matrix vector products called by the matrix created with `MatCreateSNESMF()`
2444: so users would not generally call this routine themselves.
2446: Since this function is intended for use with finite differencing it does not subtract the right hand side vector provided with `SNESSolve()`
2447: while `SNESComputeFunction()` does. As such, this routine cannot be used with `MatMFFDSetBase()` with a provided F function value even if it applies the
2448: same function as `SNESComputeFunction()` if a `SNESSolve()` right hand side vector is use because the two functions difference would include this right hand side function.
2450: .seealso: [](chapter_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `MatCreateSNESMF`
2451: @*/
2452: PetscErrorCode SNESComputeMFFunction(SNES snes, Vec x, Vec y)
2453: {
2454: DM dm;
2455: DMSNES sdm;
2457: PetscFunctionBegin;
2461: PetscCheckSameComm(snes, 1, x, 2);
2462: PetscCheckSameComm(snes, 1, y, 3);
2463: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2465: PetscCall(SNESGetDM(snes, &dm));
2466: PetscCall(DMGetDMSNES(dm, &sdm));
2467: PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2468: PetscCall(VecLockReadPush(x));
2469: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2470: snes->domainerror = PETSC_FALSE;
2471: PetscCallBack("SNES callback function", (*sdm->ops->computemffunction)(snes, x, y, sdm->mffunctionctx));
2472: PetscCall(VecLockReadPop(x));
2473: PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2474: snes->nfuncs++;
2475: /*
2476: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2477: propagate the value to all processes
2478: */
2479: if (snes->domainerror) PetscCall(VecSetInf(y));
2480: PetscFunctionReturn(PETSC_SUCCESS);
2481: }
2483: /*@
2484: SNESComputeNGS - Calls the Gauss-Seidel function that has been set with `SNESSetNGS()`.
2486: Collective
2488: Input Parameters:
2489: + snes - the `SNES` context
2490: . x - input vector
2491: - b - rhs vector
2493: Output Parameter:
2494: . x - new solution vector
2496: Level: developer
2498: Note:
2499: `SNESComputeNGS()` is typically used within composed nonlinear solver
2500: implementations, so most users would not generally call this routine
2501: themselves.
2503: .seealso: [](chapter_snes), `SNESNGS`, `SNESSetNGS()`, `SNESComputeFunction()`
2504: @*/
2505: PetscErrorCode SNESComputeNGS(SNES snes, Vec b, Vec x)
2506: {
2507: DM dm;
2508: DMSNES sdm;
2510: PetscFunctionBegin;
2514: PetscCheckSameComm(snes, 1, x, 3);
2515: if (b) PetscCheckSameComm(snes, 1, b, 2);
2516: if (b) PetscCall(VecValidValues_Internal(b, 2, PETSC_TRUE));
2517: PetscCall(PetscLogEventBegin(SNES_NGSEval, snes, x, b, 0));
2518: PetscCall(SNESGetDM(snes, &dm));
2519: PetscCall(DMGetDMSNES(dm, &sdm));
2520: PetscCheck(sdm->ops->computegs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2521: if (b) PetscCall(VecLockReadPush(b));
2522: PetscCallBack("SNES callback NGS", (*sdm->ops->computegs)(snes, x, b, sdm->gsctx));
2523: if (b) PetscCall(VecLockReadPop(b));
2524: PetscCall(PetscLogEventEnd(SNES_NGSEval, snes, x, b, 0));
2525: PetscFunctionReturn(PETSC_SUCCESS);
2526: }
2528: PetscErrorCode SNESTestJacobian(SNES snes)
2529: {
2530: Mat A, B, C, D, jacobian;
2531: Vec x = snes->vec_sol, f = snes->vec_func;
2532: PetscReal nrm, gnorm;
2533: PetscReal threshold = 1.e-5;
2534: MatType mattype;
2535: PetscInt m, n, M, N;
2536: void *functx;
2537: PetscBool complete_print = PETSC_FALSE, threshold_print = PETSC_FALSE, test = PETSC_FALSE, flg, istranspose;
2538: PetscViewer viewer, mviewer;
2539: MPI_Comm comm;
2540: PetscInt tabs;
2541: static PetscBool directionsprinted = PETSC_FALSE;
2542: PetscViewerFormat format;
2544: PetscFunctionBegin;
2545: PetscObjectOptionsBegin((PetscObject)snes);
2546: PetscCall(PetscOptionsName("-snes_test_jacobian", "Compare hand-coded and finite difference Jacobians", "None", &test));
2547: PetscCall(PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold, NULL));
2548: PetscCall(PetscOptionsViewer("-snes_test_jacobian_view", "View difference between hand-coded and finite difference Jacobians element entries", "None", &mviewer, &format, &complete_print));
2549: if (!complete_print) {
2550: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display", "-snes_test_jacobian_view", "3.13", NULL));
2551: PetscCall(PetscOptionsViewer("-snes_test_jacobian_display", "Display difference between hand-coded and finite difference Jacobians", "None", &mviewer, &format, &complete_print));
2552: }
2553: /* for compatibility with PETSc 3.9 and older. */
2554: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display_threshold", "-snes_test_jacobian", "3.13", "-snes_test_jacobian accepts an optional threshold (since v3.10)"));
2555: PetscCall(PetscOptionsReal("-snes_test_jacobian_display_threshold", "Display difference between hand-coded and finite difference Jacobians which exceed input threshold", "None", threshold, &threshold, &threshold_print));
2556: PetscOptionsEnd();
2557: if (!test) PetscFunctionReturn(PETSC_SUCCESS);
2559: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2560: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2561: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2562: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2563: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian -------------\n"));
2564: if (!complete_print && !directionsprinted) {
2565: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n"));
2566: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference Jacobian entries greater than <threshold>.\n"));
2567: }
2568: if (!directionsprinted) {
2569: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n"));
2570: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Jacobian is probably correct.\n"));
2571: directionsprinted = PETSC_TRUE;
2572: }
2573: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2575: PetscCall(PetscObjectTypeCompare((PetscObject)snes->jacobian, MATMFFD, &flg));
2576: if (!flg) jacobian = snes->jacobian;
2577: else jacobian = snes->jacobian_pre;
2579: if (!x) {
2580: PetscCall(MatCreateVecs(jacobian, &x, NULL));
2581: } else {
2582: PetscCall(PetscObjectReference((PetscObject)x));
2583: }
2584: if (!f) {
2585: PetscCall(VecDuplicate(x, &f));
2586: } else {
2587: PetscCall(PetscObjectReference((PetscObject)f));
2588: }
2589: /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2590: PetscCall(SNESComputeFunction(snes, x, f));
2591: PetscCall(VecDestroy(&f));
2592: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESKSPTRANSPOSEONLY, &istranspose));
2593: while (jacobian) {
2594: Mat JT = NULL, Jsave = NULL;
2596: if (istranspose) {
2597: PetscCall(MatCreateTranspose(jacobian, &JT));
2598: Jsave = jacobian;
2599: jacobian = JT;
2600: }
2601: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)jacobian, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
2602: if (flg) {
2603: A = jacobian;
2604: PetscCall(PetscObjectReference((PetscObject)A));
2605: } else {
2606: PetscCall(MatComputeOperator(jacobian, MATAIJ, &A));
2607: }
2609: PetscCall(MatGetType(A, &mattype));
2610: PetscCall(MatGetSize(A, &M, &N));
2611: PetscCall(MatGetLocalSize(A, &m, &n));
2612: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &B));
2613: PetscCall(MatSetType(B, mattype));
2614: PetscCall(MatSetSizes(B, m, n, M, N));
2615: PetscCall(MatSetBlockSizesFromMats(B, A, A));
2616: PetscCall(MatSetUp(B));
2617: PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2619: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
2620: PetscCall(SNESComputeJacobianDefault(snes, x, B, B, functx));
2622: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &D));
2623: PetscCall(MatAYPX(D, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2624: PetscCall(MatNorm(D, NORM_FROBENIUS, &nrm));
2625: PetscCall(MatNorm(A, NORM_FROBENIUS, &gnorm));
2626: PetscCall(MatDestroy(&D));
2627: if (!gnorm) gnorm = 1; /* just in case */
2628: PetscCall(PetscViewerASCIIPrintf(viewer, " ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n", (double)(nrm / gnorm), (double)nrm));
2630: if (complete_print) {
2631: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded Jacobian ----------\n"));
2632: PetscCall(MatView(A, mviewer));
2633: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference Jacobian ----------\n"));
2634: PetscCall(MatView(B, mviewer));
2635: }
2637: if (threshold_print || complete_print) {
2638: PetscInt Istart, Iend, *ccols, bncols, cncols, j, row;
2639: PetscScalar *cvals;
2640: const PetscInt *bcols;
2641: const PetscScalar *bvals;
2643: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2644: PetscCall(MatSetType(C, mattype));
2645: PetscCall(MatSetSizes(C, m, n, M, N));
2646: PetscCall(MatSetBlockSizesFromMats(C, A, A));
2647: PetscCall(MatSetUp(C));
2648: PetscCall(MatSetOption(C, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2650: PetscCall(MatAYPX(B, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2651: PetscCall(MatGetOwnershipRange(B, &Istart, &Iend));
2653: for (row = Istart; row < Iend; row++) {
2654: PetscCall(MatGetRow(B, row, &bncols, &bcols, &bvals));
2655: PetscCall(PetscMalloc2(bncols, &ccols, bncols, &cvals));
2656: for (j = 0, cncols = 0; j < bncols; j++) {
2657: if (PetscAbsScalar(bvals[j]) > threshold) {
2658: ccols[cncols] = bcols[j];
2659: cvals[cncols] = bvals[j];
2660: cncols += 1;
2661: }
2662: }
2663: if (cncols) PetscCall(MatSetValues(C, 1, &row, cncols, ccols, cvals, INSERT_VALUES));
2664: PetscCall(MatRestoreRow(B, row, &bncols, &bcols, &bvals));
2665: PetscCall(PetscFree2(ccols, cvals));
2666: }
2667: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2668: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2669: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n", (double)threshold));
2670: PetscCall(MatView(C, complete_print ? mviewer : viewer));
2671: PetscCall(MatDestroy(&C));
2672: }
2673: PetscCall(MatDestroy(&A));
2674: PetscCall(MatDestroy(&B));
2675: PetscCall(MatDestroy(&JT));
2676: if (Jsave) jacobian = Jsave;
2677: if (jacobian != snes->jacobian_pre) {
2678: jacobian = snes->jacobian_pre;
2679: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian for preconditioner -------------\n"));
2680: } else jacobian = NULL;
2681: }
2682: PetscCall(VecDestroy(&x));
2683: if (complete_print) PetscCall(PetscViewerPopFormat(mviewer));
2684: if (mviewer) PetscCall(PetscViewerDestroy(&mviewer));
2685: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2686: PetscFunctionReturn(PETSC_SUCCESS);
2687: }
2689: /*@
2690: SNESComputeJacobian - Computes the Jacobian matrix that has been set with `SNESSetJacobian()`.
2692: Collective
2694: Input Parameters:
2695: + snes - the `SNES` context
2696: - x - input vector
2698: Output Parameters:
2699: + A - Jacobian matrix
2700: - B - optional matrix for building the preconditioner
2702: Options Database Keys:
2703: + -snes_lag_preconditioner <lag> - how often to rebuild preconditioner
2704: . -snes_lag_jacobian <lag> - how often to rebuild Jacobian
2705: . -snes_test_jacobian <optional threshold> - compare the user provided Jacobian with one compute via finite differences to check for errors. If a threshold is given, display only those entries whose difference is greater than the threshold.
2706: . -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference between them to help users detect the location of errors in the user provided Jacobian
2707: . -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2708: . -snes_compare_explicit_draw - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2709: . -snes_compare_explicit_contour - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2710: . -snes_compare_operator - Make the comparison options above use the operator instead of the preconditioning matrix
2711: . -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2712: . -snes_compare_coloring_display - Compute the finite difference Jacobian using coloring and display verbose differences
2713: . -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2714: . -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2715: . -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2716: . -snes_compare_coloring_draw - Compute the finite difference Jacobian using coloring and draw differences
2717: - -snes_compare_coloring_draw_contour - Compute the finite difference Jacobian using coloring and show contours of matrices and differences
2719: Level: developer
2721: Note:
2722: Most users should not need to explicitly call this routine, as it
2723: is used internally within the nonlinear solvers.
2725: Developer Note:
2726: This has duplicative ways of checking the accuracy of the user provided Jacobian (see the options above). This is for historical reasons, the routine `SNESTestJacobian()` use to used
2727: for with the `SNESType` of test that has been removed.
2729: .seealso: [](chapter_snes), `SNESSetJacobian()`, `KSPSetOperators()`, `MatStructure`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
2730: @*/
2731: PetscErrorCode SNESComputeJacobian(SNES snes, Vec X, Mat A, Mat B)
2732: {
2733: PetscBool flag;
2734: DM dm;
2735: DMSNES sdm;
2736: KSP ksp;
2738: PetscFunctionBegin;
2741: PetscCheckSameComm(snes, 1, X, 2);
2742: PetscCall(VecValidValues_Internal(X, 2, PETSC_TRUE));
2743: PetscCall(SNESGetDM(snes, &dm));
2744: PetscCall(DMGetDMSNES(dm, &sdm));
2746: /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */
2747: if (snes->lagjacobian == -2) {
2748: snes->lagjacobian = -1;
2750: PetscCall(PetscInfo(snes, "Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n"));
2751: } else if (snes->lagjacobian == -1) {
2752: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is -1\n"));
2753: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2754: if (flag) {
2755: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2756: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2757: }
2758: PetscFunctionReturn(PETSC_SUCCESS);
2759: } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2760: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagjacobian, snes->iter));
2761: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2762: if (flag) {
2763: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2764: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2765: }
2766: PetscFunctionReturn(PETSC_SUCCESS);
2767: }
2768: if (snes->npc && snes->npcside == PC_LEFT) {
2769: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2770: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2771: PetscFunctionReturn(PETSC_SUCCESS);
2772: }
2774: PetscCall(PetscLogEventBegin(SNES_JacobianEval, snes, X, A, B));
2775: PetscCall(VecLockReadPush(X));
2776: {
2777: void *ctx;
2778: PetscErrorCode (*J)(SNES, Vec, Mat, Mat, void *);
2779: PetscCall(DMSNESGetJacobian(dm, &J, &ctx));
2780: PetscCallBack("SNES callback Jacobian", (*J)(snes, X, A, B, ctx));
2781: }
2782: PetscCall(VecLockReadPop(X));
2783: PetscCall(PetscLogEventEnd(SNES_JacobianEval, snes, X, A, B));
2785: /* attach latest linearization point to the preconditioning matrix */
2786: PetscCall(PetscObjectCompose((PetscObject)B, "__SNES_latest_X", (PetscObject)X));
2788: /* the next line ensures that snes->ksp exists */
2789: PetscCall(SNESGetKSP(snes, &ksp));
2790: if (snes->lagpreconditioner == -2) {
2791: PetscCall(PetscInfo(snes, "Rebuilding preconditioner exactly once since lag is -2\n"));
2792: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2793: snes->lagpreconditioner = -1;
2794: } else if (snes->lagpreconditioner == -1) {
2795: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is -1\n"));
2796: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2797: } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2798: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagpreconditioner, snes->iter));
2799: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2800: } else {
2801: PetscCall(PetscInfo(snes, "Rebuilding preconditioner\n"));
2802: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2803: }
2805: PetscCall(SNESTestJacobian(snes));
2806: /* make sure user returned a correct Jacobian and preconditioner */
2809: {
2810: PetscBool flag = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_operator = PETSC_FALSE;
2811: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit", NULL, NULL, &flag));
2812: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw", NULL, NULL, &flag_draw));
2813: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw_contour", NULL, NULL, &flag_contour));
2814: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_operator", NULL, NULL, &flag_operator));
2815: if (flag || flag_draw || flag_contour) {
2816: Mat Bexp_mine = NULL, Bexp, FDexp;
2817: PetscViewer vdraw, vstdout;
2818: PetscBool flg;
2819: if (flag_operator) {
2820: PetscCall(MatComputeOperator(A, MATAIJ, &Bexp_mine));
2821: Bexp = Bexp_mine;
2822: } else {
2823: /* See if the preconditioning matrix can be viewed and added directly */
2824: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)B, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPIBAIJ, ""));
2825: if (flg) Bexp = B;
2826: else {
2827: /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2828: PetscCall(MatComputeOperator(B, MATAIJ, &Bexp_mine));
2829: Bexp = Bexp_mine;
2830: }
2831: }
2832: PetscCall(MatConvert(Bexp, MATSAME, MAT_INITIAL_MATRIX, &FDexp));
2833: PetscCall(SNESComputeJacobianDefault(snes, X, FDexp, FDexp, NULL));
2834: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
2835: if (flag_draw || flag_contour) {
2836: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Explicit Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
2837: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
2838: } else vdraw = NULL;
2839: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit %s\n", flag_operator ? "Jacobian" : "preconditioning Jacobian"));
2840: if (flag) PetscCall(MatView(Bexp, vstdout));
2841: if (vdraw) PetscCall(MatView(Bexp, vdraw));
2842: PetscCall(PetscViewerASCIIPrintf(vstdout, "Finite difference Jacobian\n"));
2843: if (flag) PetscCall(MatView(FDexp, vstdout));
2844: if (vdraw) PetscCall(MatView(FDexp, vdraw));
2845: PetscCall(MatAYPX(FDexp, -1.0, Bexp, SAME_NONZERO_PATTERN));
2846: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian\n"));
2847: if (flag) PetscCall(MatView(FDexp, vstdout));
2848: if (vdraw) { /* Always use contour for the difference */
2849: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
2850: PetscCall(MatView(FDexp, vdraw));
2851: PetscCall(PetscViewerPopFormat(vdraw));
2852: }
2853: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
2854: PetscCall(PetscViewerDestroy(&vdraw));
2855: PetscCall(MatDestroy(&Bexp_mine));
2856: PetscCall(MatDestroy(&FDexp));
2857: }
2858: }
2859: {
2860: PetscBool flag = PETSC_FALSE, flag_display = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_threshold = PETSC_FALSE;
2861: PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON, threshold_rtol = 10 * PETSC_SQRT_MACHINE_EPSILON;
2862: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring", NULL, NULL, &flag));
2863: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_display", NULL, NULL, &flag_display));
2864: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw", NULL, NULL, &flag_draw));
2865: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw_contour", NULL, NULL, &flag_contour));
2866: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold", NULL, NULL, &flag_threshold));
2867: if (flag_threshold) {
2868: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_rtol", &threshold_rtol, NULL));
2869: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_atol", &threshold_atol, NULL));
2870: }
2871: if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2872: Mat Bfd;
2873: PetscViewer vdraw, vstdout;
2874: MatColoring coloring;
2875: ISColoring iscoloring;
2876: MatFDColoring matfdcoloring;
2877: PetscErrorCode (*func)(SNES, Vec, Vec, void *);
2878: void *funcctx;
2879: PetscReal norm1, norm2, normmax;
2881: PetscCall(MatDuplicate(B, MAT_DO_NOT_COPY_VALUES, &Bfd));
2882: PetscCall(MatColoringCreate(Bfd, &coloring));
2883: PetscCall(MatColoringSetType(coloring, MATCOLORINGSL));
2884: PetscCall(MatColoringSetFromOptions(coloring));
2885: PetscCall(MatColoringApply(coloring, &iscoloring));
2886: PetscCall(MatColoringDestroy(&coloring));
2887: PetscCall(MatFDColoringCreate(Bfd, iscoloring, &matfdcoloring));
2888: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
2889: PetscCall(MatFDColoringSetUp(Bfd, iscoloring, matfdcoloring));
2890: PetscCall(ISColoringDestroy(&iscoloring));
2892: /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2893: PetscCall(SNESGetFunction(snes, NULL, &func, &funcctx));
2894: PetscCall(MatFDColoringSetFunction(matfdcoloring, (PetscErrorCode(*)(void))func, funcctx));
2895: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring, ((PetscObject)snes)->prefix));
2896: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring, "coloring_"));
2897: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
2898: PetscCall(MatFDColoringApply(Bfd, matfdcoloring, X, snes));
2899: PetscCall(MatFDColoringDestroy(&matfdcoloring));
2901: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
2902: if (flag_draw || flag_contour) {
2903: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Colored Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
2904: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
2905: } else vdraw = NULL;
2906: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit preconditioning Jacobian\n"));
2907: if (flag_display) PetscCall(MatView(B, vstdout));
2908: if (vdraw) PetscCall(MatView(B, vdraw));
2909: PetscCall(PetscViewerASCIIPrintf(vstdout, "Colored Finite difference Jacobian\n"));
2910: if (flag_display) PetscCall(MatView(Bfd, vstdout));
2911: if (vdraw) PetscCall(MatView(Bfd, vdraw));
2912: PetscCall(MatAYPX(Bfd, -1.0, B, SAME_NONZERO_PATTERN));
2913: PetscCall(MatNorm(Bfd, NORM_1, &norm1));
2914: PetscCall(MatNorm(Bfd, NORM_FROBENIUS, &norm2));
2915: PetscCall(MatNorm(Bfd, NORM_MAX, &normmax));
2916: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n", (double)norm1, (double)norm2, (double)normmax));
2917: if (flag_display) PetscCall(MatView(Bfd, vstdout));
2918: if (vdraw) { /* Always use contour for the difference */
2919: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
2920: PetscCall(MatView(Bfd, vdraw));
2921: PetscCall(PetscViewerPopFormat(vdraw));
2922: }
2923: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
2925: if (flag_threshold) {
2926: PetscInt bs, rstart, rend, i;
2927: PetscCall(MatGetBlockSize(B, &bs));
2928: PetscCall(MatGetOwnershipRange(B, &rstart, &rend));
2929: for (i = rstart; i < rend; i++) {
2930: const PetscScalar *ba, *ca;
2931: const PetscInt *bj, *cj;
2932: PetscInt bn, cn, j, maxentrycol = -1, maxdiffcol = -1, maxrdiffcol = -1;
2933: PetscReal maxentry = 0, maxdiff = 0, maxrdiff = 0;
2934: PetscCall(MatGetRow(B, i, &bn, &bj, &ba));
2935: PetscCall(MatGetRow(Bfd, i, &cn, &cj, &ca));
2936: PetscCheck(bn == cn, ((PetscObject)A)->comm, PETSC_ERR_PLIB, "Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2937: for (j = 0; j < bn; j++) {
2938: PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
2939: if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2940: maxentrycol = bj[j];
2941: maxentry = PetscRealPart(ba[j]);
2942: }
2943: if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2944: maxdiffcol = bj[j];
2945: maxdiff = PetscRealPart(ca[j]);
2946: }
2947: if (rdiff > maxrdiff) {
2948: maxrdiffcol = bj[j];
2949: maxrdiff = rdiff;
2950: }
2951: }
2952: if (maxrdiff > 1) {
2953: PetscCall(PetscViewerASCIIPrintf(vstdout, "row %" PetscInt_FMT " (maxentry=%g at %" PetscInt_FMT ", maxdiff=%g at %" PetscInt_FMT ", maxrdiff=%g at %" PetscInt_FMT "):", i, (double)maxentry, maxentrycol, (double)maxdiff, maxdiffcol, (double)maxrdiff, maxrdiffcol));
2954: for (j = 0; j < bn; j++) {
2955: PetscReal rdiff;
2956: rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
2957: if (rdiff > 1) PetscCall(PetscViewerASCIIPrintf(vstdout, " (%" PetscInt_FMT ",%g:%g)", bj[j], (double)PetscRealPart(ba[j]), (double)PetscRealPart(ca[j])));
2958: }
2959: PetscCall(PetscViewerASCIIPrintf(vstdout, "\n"));
2960: }
2961: PetscCall(MatRestoreRow(B, i, &bn, &bj, &ba));
2962: PetscCall(MatRestoreRow(Bfd, i, &cn, &cj, &ca));
2963: }
2964: }
2965: PetscCall(PetscViewerDestroy(&vdraw));
2966: PetscCall(MatDestroy(&Bfd));
2967: }
2968: }
2969: PetscFunctionReturn(PETSC_SUCCESS);
2970: }
2972: /*MC
2973: SNESJacobianFunction - Function used by `SNES` to compute the nonlinear Jacobian of the function to be solved by `SNES`
2975: Synopsis:
2976: #include "petscsnes.h"
2977: PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);
2979: Collective
2981: Input Parameters:
2982: + x - input vector, the Jacobian is to be computed at this value
2983: - ctx - [optional] user-defined Jacobian context
2985: Output Parameters:
2986: + Amat - the matrix that defines the (approximate) Jacobian
2987: - Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
2989: Level: intermediate
2991: .seealso: [](chapter_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESSetJacobian()`, `SNESGetJacobian()`
2992: M*/
2994: /*@C
2995: SNESSetJacobian - Sets the function to compute Jacobian as well as the
2996: location to store the matrix.
2998: Logically Collective
3000: Input Parameters:
3001: + snes - the `SNES` context
3002: . Amat - the matrix that defines the (approximate) Jacobian
3003: . Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
3004: . J - Jacobian evaluation routine (if `NULL` then `SNES` retains any previously set value), see `SNESJacobianFunction` for details
3005: - ctx - [optional] user-defined context for private data for the
3006: Jacobian evaluation routine (may be `NULL`) (if `NULL` then `SNES` retains any previously set value)
3008: Level: beginner
3010: Notes:
3011: If the `Amat` matrix and `Pmat` matrix are different you must call `MatAssemblyBegin()`/`MatAssemblyEnd()` on
3012: each matrix.
3014: If you know the operator `Amat` has a null space you can use `MatSetNullSpace()` and `MatSetTransposeNullSpace()` to supply the null
3015: space to `Amat` and the `KSP` solvers will automatically use that null space as needed during the solution process.
3017: If using `SNESComputeJacobianDefaultColor()` to assemble a Jacobian, the `ctx` argument
3018: must be a `MatFDColoring`.
3020: Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian. One common
3021: example is to use the "Picard linearization" which only differentiates through the highest order parts of each term using `SNESSetPicard()`
3023: .seealso: [](chapter_snes), `SNES`, `KSPSetOperators()`, `SNESSetFunction()`, `MatMFFDComputeJacobian()`, `SNESComputeJacobianDefaultColor()`, `MatStructure`,
3024: `SNESSetPicard()`, `SNESJacobianFunction`
3025: @*/
3026: PetscErrorCode SNESSetJacobian(SNES snes, Mat Amat, Mat Pmat, PetscErrorCode (*J)(SNES, Vec, Mat, Mat, void *), void *ctx)
3027: {
3028: DM dm;
3030: PetscFunctionBegin;
3034: if (Amat) PetscCheckSameComm(snes, 1, Amat, 2);
3035: if (Pmat) PetscCheckSameComm(snes, 1, Pmat, 3);
3036: PetscCall(SNESGetDM(snes, &dm));
3037: PetscCall(DMSNESSetJacobian(dm, J, ctx));
3038: if (Amat) {
3039: PetscCall(PetscObjectReference((PetscObject)Amat));
3040: PetscCall(MatDestroy(&snes->jacobian));
3042: snes->jacobian = Amat;
3043: }
3044: if (Pmat) {
3045: PetscCall(PetscObjectReference((PetscObject)Pmat));
3046: PetscCall(MatDestroy(&snes->jacobian_pre));
3048: snes->jacobian_pre = Pmat;
3049: }
3050: PetscFunctionReturn(PETSC_SUCCESS);
3051: }
3053: /*@C
3054: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
3055: provided context for evaluating the Jacobian.
3057: Not Collective, but `Mat` object will be parallel if `SNES` object is
3059: Input Parameter:
3060: . snes - the nonlinear solver context
3062: Output Parameters:
3063: + Amat - location to stash (approximate) Jacobian matrix (or `NULL`)
3064: . Pmat - location to stash matrix used to compute the preconditioner (or `NULL`)
3065: . J - location to put Jacobian function (or `NULL`), for calling sequence see `SNESJacobianFunction`
3066: - ctx - location to stash Jacobian ctx (or `NULL`)
3068: Level: advanced
3070: .seealso: [](chapter_snes), `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFunction`, `SNESGetFunction()`
3071: @*/
3072: PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, PetscErrorCode (**J)(SNES, Vec, Mat, Mat, void *), void **ctx)
3073: {
3074: DM dm;
3076: PetscFunctionBegin;
3078: if (Amat) *Amat = snes->jacobian;
3079: if (Pmat) *Pmat = snes->jacobian_pre;
3080: PetscCall(SNESGetDM(snes, &dm));
3081: PetscCall(DMSNESGetJacobian(dm, J, ctx));
3082: PetscFunctionReturn(PETSC_SUCCESS);
3083: }
3085: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3086: {
3087: DM dm;
3088: DMSNES sdm;
3090: PetscFunctionBegin;
3091: PetscCall(SNESGetDM(snes, &dm));
3092: PetscCall(DMGetDMSNES(dm, &sdm));
3093: if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3094: DM dm;
3095: PetscBool isdense, ismf;
3097: PetscCall(SNESGetDM(snes, &dm));
3098: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &isdense, MATSEQDENSE, MATMPIDENSE, MATDENSE, NULL));
3099: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &ismf, MATMFFD, MATSHELL, NULL));
3100: if (isdense) {
3101: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefault, NULL));
3102: } else if (!ismf) {
3103: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefaultColor, NULL));
3104: }
3105: }
3106: PetscFunctionReturn(PETSC_SUCCESS);
3107: }
3109: /*@
3110: SNESSetUp - Sets up the internal data structures for the later use
3111: of a nonlinear solver.
3113: Collective
3115: Input Parameter:
3116: . snes - the `SNES` context
3118: Level: advanced
3120: Note:
3121: For basic use of the `SNES` solvers the user need not explicitly call
3122: `SNESSetUp()`, since these actions will automatically occur during
3123: the call to `SNESSolve()`. However, if one wishes to control this
3124: phase separately, `SNESSetUp()` should be called after `SNESCreate()`
3125: and optional routines of the form SNESSetXXX(), but before `SNESSolve()`.
3127: .seealso: [](chapter_snes), `SNES`, `SNESCreate()`, `SNESSolve()`, `SNESDestroy()`
3128: @*/
3129: PetscErrorCode SNESSetUp(SNES snes)
3130: {
3131: DM dm;
3132: DMSNES sdm;
3133: SNESLineSearch linesearch, pclinesearch;
3134: void *lsprectx, *lspostctx;
3135: PetscBool mf_operator, mf;
3136: Vec f, fpc;
3137: void *funcctx;
3138: void *jacctx, *appctx;
3139: Mat j, jpre;
3140: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, void *);
3141: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *);
3142: PetscErrorCode (*func)(SNES, Vec, Vec, void *);
3143: PetscErrorCode (*jac)(SNES, Vec, Mat, Mat, void *);
3145: PetscFunctionBegin;
3147: if (snes->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
3148: PetscCall(PetscLogEventBegin(SNES_SetUp, snes, 0, 0, 0));
3150: if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, SNESNEWTONLS));
3152: PetscCall(SNESGetFunction(snes, &snes->vec_func, NULL, NULL));
3154: PetscCall(SNESGetDM(snes, &dm));
3155: PetscCall(DMGetDMSNES(dm, &sdm));
3156: PetscCall(SNESSetDefaultComputeJacobian(snes));
3158: if (!snes->vec_func) PetscCall(DMCreateGlobalVector(dm, &snes->vec_func));
3160: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
3162: if (snes->linesearch) {
3163: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
3164: PetscCall(SNESLineSearchSetFunction(snes->linesearch, SNESComputeFunction));
3165: }
3167: PetscCall(SNESGetUseMatrixFree(snes, &mf_operator, &mf));
3168: if (snes->npc && snes->npcside == PC_LEFT) {
3169: snes->mf = PETSC_TRUE;
3170: snes->mf_operator = PETSC_FALSE;
3171: }
3173: if (snes->npc) {
3174: /* copy the DM over */
3175: PetscCall(SNESGetDM(snes, &dm));
3176: PetscCall(SNESSetDM(snes->npc, dm));
3178: PetscCall(SNESGetFunction(snes, &f, &func, &funcctx));
3179: PetscCall(VecDuplicate(f, &fpc));
3180: PetscCall(SNESSetFunction(snes->npc, fpc, func, funcctx));
3181: PetscCall(SNESGetJacobian(snes, &j, &jpre, &jac, &jacctx));
3182: PetscCall(SNESSetJacobian(snes->npc, j, jpre, jac, jacctx));
3183: PetscCall(SNESGetApplicationContext(snes, &appctx));
3184: PetscCall(SNESSetApplicationContext(snes->npc, appctx));
3185: PetscCall(SNESSetUseMatrixFree(snes->npc, mf_operator, mf));
3186: PetscCall(VecDestroy(&fpc));
3188: /* copy the function pointers over */
3189: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)snes->npc));
3191: /* default to 1 iteration */
3192: PetscCall(SNESSetTolerances(snes->npc, 0.0, 0.0, 0.0, 1, snes->npc->max_funcs));
3193: if (snes->npcside == PC_RIGHT) {
3194: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_FINAL_ONLY));
3195: } else {
3196: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_NONE));
3197: }
3198: PetscCall(SNESSetFromOptions(snes->npc));
3200: /* copy the line search context over */
3201: if (snes->linesearch && snes->npc->linesearch) {
3202: PetscCall(SNESGetLineSearch(snes, &linesearch));
3203: PetscCall(SNESGetLineSearch(snes->npc, &pclinesearch));
3204: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
3205: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
3206: PetscCall(SNESLineSearchSetPreCheck(pclinesearch, precheck, lsprectx));
3207: PetscCall(SNESLineSearchSetPostCheck(pclinesearch, postcheck, lspostctx));
3208: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch));
3209: }
3210: }
3211: if (snes->mf) PetscCall(SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version));
3212: if (snes->ops->usercompute && !snes->user) PetscCall((*snes->ops->usercompute)(snes, (void **)&snes->user));
3214: snes->jac_iter = 0;
3215: snes->pre_iter = 0;
3217: PetscTryTypeMethod(snes, setup);
3219: PetscCall(SNESSetDefaultComputeJacobian(snes));
3221: if (snes->npc && snes->npcside == PC_LEFT) {
3222: if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3223: if (snes->linesearch) {
3224: PetscCall(SNESGetLineSearch(snes, &linesearch));
3225: PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunctionDefaultNPC));
3226: }
3227: }
3228: }
3229: PetscCall(PetscLogEventEnd(SNES_SetUp, snes, 0, 0, 0));
3230: snes->setupcalled = PETSC_TRUE;
3231: PetscFunctionReturn(PETSC_SUCCESS);
3232: }
3234: /*@
3235: SNESReset - Resets a `SNES` context to the snessetupcalled = 0 state and removes any allocated `Vec`s and `Mat`s
3237: Collective
3239: Input Parameter:
3240: . snes - iterative context obtained from `SNESCreate()`
3242: Level: intermediate
3244: Notes:
3245: Call this if you wish to reuse a `SNES` but with different size vectors
3247: Also calls the application context destroy routine set with `SNESSetComputeApplicationContext()`
3249: .seealso: [](chapter_snes), `SNES`, `SNESDestroy()`, `SNESCreate()`, `SNESSetUp()`, `SNESSolve()`
3250: @*/
3251: PetscErrorCode SNESReset(SNES snes)
3252: {
3253: PetscFunctionBegin;
3255: if (snes->ops->userdestroy && snes->user) {
3256: PetscCall((*snes->ops->userdestroy)((void **)&snes->user));
3257: snes->user = NULL;
3258: }
3259: if (snes->npc) PetscCall(SNESReset(snes->npc));
3261: PetscTryTypeMethod(snes, reset);
3262: if (snes->ksp) PetscCall(KSPReset(snes->ksp));
3264: if (snes->linesearch) PetscCall(SNESLineSearchReset(snes->linesearch));
3266: PetscCall(VecDestroy(&snes->vec_rhs));
3267: PetscCall(VecDestroy(&snes->vec_sol));
3268: PetscCall(VecDestroy(&snes->vec_sol_update));
3269: PetscCall(VecDestroy(&snes->vec_func));
3270: PetscCall(MatDestroy(&snes->jacobian));
3271: PetscCall(MatDestroy(&snes->jacobian_pre));
3272: PetscCall(MatDestroy(&snes->picard));
3273: PetscCall(VecDestroyVecs(snes->nwork, &snes->work));
3274: PetscCall(VecDestroyVecs(snes->nvwork, &snes->vwork));
3276: snes->alwayscomputesfinalresidual = PETSC_FALSE;
3278: snes->nwork = snes->nvwork = 0;
3279: snes->setupcalled = PETSC_FALSE;
3280: PetscFunctionReturn(PETSC_SUCCESS);
3281: }
3283: /*@
3284: SNESConvergedReasonViewCancel - Clears all the reason view functions for a `SNES` object.
3286: Collective
3288: Input Parameter:
3289: . snes - iterative context obtained from `SNESCreate()`
3291: Level: intermediate
3293: .seealso: [](chapter_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESReset()`
3294: @*/
3295: PetscErrorCode SNESConvergedReasonViewCancel(SNES snes)
3296: {
3297: PetscInt i;
3299: PetscFunctionBegin;
3301: for (i = 0; i < snes->numberreasonviews; i++) {
3302: if (snes->reasonviewdestroy[i]) PetscCall((*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]));
3303: }
3304: snes->numberreasonviews = 0;
3305: PetscFunctionReturn(PETSC_SUCCESS);
3306: }
3308: /*@C
3309: SNESDestroy - Destroys the nonlinear solver context that was created
3310: with `SNESCreate()`.
3312: Collective
3314: Input Parameter:
3315: . snes - the `SNES` context
3317: Level: beginner
3319: .seealso: [](chapter_snes), `SNES`, `SNESCreate()`, `SNESSolve()`
3320: @*/
3321: PetscErrorCode SNESDestroy(SNES *snes)
3322: {
3323: PetscFunctionBegin;
3324: if (!*snes) PetscFunctionReturn(PETSC_SUCCESS);
3326: if (--((PetscObject)(*snes))->refct > 0) {
3327: *snes = NULL;
3328: PetscFunctionReturn(PETSC_SUCCESS);
3329: }
3331: PetscCall(SNESReset((*snes)));
3332: PetscCall(SNESDestroy(&(*snes)->npc));
3334: /* if memory was published with SAWs then destroy it */
3335: PetscCall(PetscObjectSAWsViewOff((PetscObject)*snes));
3336: PetscTryTypeMethod((*snes), destroy);
3338: if ((*snes)->dm) PetscCall(DMCoarsenHookRemove((*snes)->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, *snes));
3339: PetscCall(DMDestroy(&(*snes)->dm));
3340: PetscCall(KSPDestroy(&(*snes)->ksp));
3341: PetscCall(SNESLineSearchDestroy(&(*snes)->linesearch));
3343: PetscCall(PetscFree((*snes)->kspconvctx));
3344: if ((*snes)->ops->convergeddestroy) PetscCall((*(*snes)->ops->convergeddestroy)((*snes)->cnvP));
3345: if ((*snes)->conv_hist_alloc) PetscCall(PetscFree2((*snes)->conv_hist, (*snes)->conv_hist_its));
3346: PetscCall(SNESMonitorCancel((*snes)));
3347: PetscCall(SNESConvergedReasonViewCancel((*snes)));
3348: PetscCall(PetscHeaderDestroy(snes));
3349: PetscFunctionReturn(PETSC_SUCCESS);
3350: }
3352: /* ----------- Routines to set solver parameters ---------- */
3354: /*@
3355: SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.
3357: Logically Collective
3359: Input Parameters:
3360: + snes - the `SNES` context
3361: - lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3362: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3364: Options Database Keys:
3365: + -snes_lag_jacobian_persists <true,false> - sets the persistence
3366: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3367: . -snes_lag_preconditioner_persists <true,false> - sets the persistence
3368: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3370: Notes:
3371: Level: intermediate
3373: The default is 1
3374: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagPreconditionerPersists()` was called
3376: `SNESSetLagPreconditionerPersists()` allows using the same uniform lagging (for example every second linear solve) across multiple nonlinear solves.
3378: .seealso: [](chapter_snes), `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetLagPreconditionerPersists()`,
3379: `SNESSetLagJacobianPersists()`, `SNES`, `SNESSolve()`
3380: @*/
3381: PetscErrorCode SNESSetLagPreconditioner(SNES snes, PetscInt lag)
3382: {
3383: PetscFunctionBegin;
3385: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3386: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3388: snes->lagpreconditioner = lag;
3389: PetscFunctionReturn(PETSC_SUCCESS);
3390: }
3392: /*@
3393: SNESSetGridSequence - sets the number of steps of grid sequencing that `SNES` will do
3395: Logically Collective
3397: Input Parameters:
3398: + snes - the `SNES` context
3399: - steps - the number of refinements to do, defaults to 0
3401: Options Database Key:
3402: . -snes_grid_sequence <steps> - Use grid sequencing to generate initial guess
3404: Level: intermediate
3406: Note:
3407: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3409: .seealso: [](chapter_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetGridSequence()`
3410: @*/
3411: PetscErrorCode SNESSetGridSequence(SNES snes, PetscInt steps)
3412: {
3413: PetscFunctionBegin;
3416: snes->gridsequence = steps;
3417: PetscFunctionReturn(PETSC_SUCCESS);
3418: }
3420: /*@
3421: SNESGetGridSequence - gets the number of steps of grid sequencing that `SNES` will do
3423: Logically Collective
3425: Input Parameter:
3426: . snes - the `SNES` context
3428: Output Parameter:
3429: . steps - the number of refinements to do, defaults to 0
3431: Options Database Key:
3432: . -snes_grid_sequence <steps> - set number of refinements
3434: Level: intermediate
3436: Note:
3437: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3439: .seealso: [](chapter_snes), `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetGridSequence()`
3440: @*/
3441: PetscErrorCode SNESGetGridSequence(SNES snes, PetscInt *steps)
3442: {
3443: PetscFunctionBegin;
3445: *steps = snes->gridsequence;
3446: PetscFunctionReturn(PETSC_SUCCESS);
3447: }
3449: /*@
3450: SNESGetLagPreconditioner - Return how often the preconditioner is rebuilt
3452: Not Collective
3454: Input Parameter:
3455: . snes - the `SNES` context
3457: Output Parameter:
3458: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3459: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3461: Options Database Keys:
3462: + -snes_lag_jacobian_persists <true,false> - sets the persistence
3463: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3464: . -snes_lag_preconditioner_persists <true,false> - sets the persistence
3465: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3467: Level: intermediate
3469: Notes:
3470: The default is 1
3472: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3474: .seealso: [](chapter_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3475: @*/
3476: PetscErrorCode SNESGetLagPreconditioner(SNES snes, PetscInt *lag)
3477: {
3478: PetscFunctionBegin;
3480: *lag = snes->lagpreconditioner;
3481: PetscFunctionReturn(PETSC_SUCCESS);
3482: }
3484: /*@
3485: SNESSetLagJacobian - Set when the Jacobian is rebuilt in the nonlinear solve. See `SNESSetLagPreconditioner()` for determining how
3486: often the preconditioner is rebuilt.
3488: Logically Collective
3490: Input Parameters:
3491: + snes - the `SNES` context
3492: - lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3493: the Jacobian is built etc. -2 means rebuild at next chance but then never again
3495: Options Database Keys:
3496: + -snes_lag_jacobian_persists <true,false> - sets the persistence
3497: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3498: . -snes_lag_preconditioner_persists <true,false> - sets the persistence
3499: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag.
3501: Level: intermediate
3503: Notes:
3504: The default is 1
3506: The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3508: If -1 is used before the very first nonlinear solve the CODE WILL FAIL! because no Jacobian is used, use -2 to indicate you want it recomputed
3509: at the next Newton step but never again (unless it is reset to another value)
3511: .seealso: [](chapter_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagPreconditioner()`, `SNESGetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3512: @*/
3513: PetscErrorCode SNESSetLagJacobian(SNES snes, PetscInt lag)
3514: {
3515: PetscFunctionBegin;
3517: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3518: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3520: snes->lagjacobian = lag;
3521: PetscFunctionReturn(PETSC_SUCCESS);
3522: }
3524: /*@
3525: SNESGetLagJacobian - Get how often the Jacobian is rebuilt. See `SNESGetLagPreconditioner()` to determine when the preconditioner is rebuilt
3527: Not Collective
3529: Input Parameter:
3530: . snes - the `SNES` context
3532: Output Parameter:
3533: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3534: the Jacobian is built etc.
3536: Level: intermediate
3538: Notes:
3539: The default is 1
3541: The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagJacobianPersists()` was called.
3543: .seealso: [](chapter_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESSetLagJacobian()`, `SNESSetLagPreconditioner()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3545: @*/
3546: PetscErrorCode SNESGetLagJacobian(SNES snes, PetscInt *lag)
3547: {
3548: PetscFunctionBegin;
3550: *lag = snes->lagjacobian;
3551: PetscFunctionReturn(PETSC_SUCCESS);
3552: }
3554: /*@
3555: SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple nonlinear solves
3557: Logically collective
3559: Input Parameters:
3560: + snes - the `SNES` context
3561: - flg - jacobian lagging persists if true
3563: Options Database Keys:
3564: + -snes_lag_jacobian_persists <true,false> - sets the persistence
3565: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3566: . -snes_lag_preconditioner_persists <true,false> - sets the persistence
3567: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3569: Level: advanced
3571: Notes:
3572: Normally when `SNESSetLagJacobian()` is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that.
3574: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3575: several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3576: timesteps may present huge efficiency gains.
3578: .seealso: [](chapter_snes), `SNES, `SNESSetLagPreconditionerPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagJacobianPersists()`
3579: @*/
3580: PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
3581: {
3582: PetscFunctionBegin;
3585: snes->lagjac_persist = flg;
3586: PetscFunctionReturn(PETSC_SUCCESS);
3587: }
3589: /*@
3590: SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves
3592: Logically Collective
3594: Input Parameters:
3595: + snes - the `SNES` context
3596: - flg - preconditioner lagging persists if true
3598: Options Database Keys:
3599: + -snes_lag_jacobian_persists <true,false> - sets the persistence
3600: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3601: . -snes_lag_preconditioner_persists <true,false> - sets the persistence
3602: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3604: Level: developer
3606: Notes:
3607: Normally when `SNESSetLagPreconditioner()` is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that.
3609: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3610: by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3611: several timesteps may present huge efficiency gains.
3613: .seealso: [](chapter_snes), `SNES`, `SNESSetLagJacobianPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagPreconditioner()`
3614: @*/
3615: PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)
3616: {
3617: PetscFunctionBegin;
3620: snes->lagpre_persist = flg;
3621: PetscFunctionReturn(PETSC_SUCCESS);
3622: }
3624: /*@
3625: SNESSetForceIteration - force `SNESSolve()` to take at least one iteration regardless of the initial residual norm
3627: Logically Collective
3629: Input Parameters:
3630: + snes - the `SNES` context
3631: - force - `PETSC_TRUE` require at least one iteration
3633: Options Database Key:
3634: . -snes_force_iteration <force> - Sets forcing an iteration
3636: Level: intermediate
3638: Note:
3639: This is used sometimes with `TS` to prevent `TS` from detecting a false steady state solution
3641: .seealso: [](chapter_snes), `SNES`, `TS`, `SNESSetTrustRegionTolerance()`, `SNESSetDivergenceTolerance()`
3642: @*/
3643: PetscErrorCode SNESSetForceIteration(SNES snes, PetscBool force)
3644: {
3645: PetscFunctionBegin;
3647: snes->forceiteration = force;
3648: PetscFunctionReturn(PETSC_SUCCESS);
3649: }
3651: /*@
3652: SNESGetForceIteration - Check whether or not `SNESSolve()` take at least one iteration regardless of the initial residual norm
3654: Logically Collective
3656: Input Parameter:
3657: . snes - the `SNES` context
3659: Output Parameter:
3660: . force - `PETSC_TRUE` requires at least one iteration.
3662: Level: intermediate
3664: .seealso: [](chapter_snes), `SNES`, `SNESSetForceIteration()`, `SNESSetTrustRegionTolerance()`, `SNESSetDivergenceTolerance()`
3665: @*/
3666: PetscErrorCode SNESGetForceIteration(SNES snes, PetscBool *force)
3667: {
3668: PetscFunctionBegin;
3670: *force = snes->forceiteration;
3671: PetscFunctionReturn(PETSC_SUCCESS);
3672: }
3674: /*@
3675: SNESSetTolerances - Sets `SNES` various parameters used in convergence tests.
3677: Logically Collective
3679: Input Parameters:
3680: + snes - the `SNES` context
3681: . abstol - absolute convergence tolerance
3682: . rtol - relative convergence tolerance
3683: . stol - convergence tolerance in terms of the norm of the change in the solution between steps, || delta x || < stol*|| x ||
3684: . maxit - maximum number of iterations, default 50.
3685: - maxf - maximum number of function evaluations (-1 indicates no limit), default 1000
3687: Options Database Keys:
3688: + -snes_atol <abstol> - Sets abstol
3689: . -snes_rtol <rtol> - Sets rtol
3690: . -snes_stol <stol> - Sets stol
3691: . -snes_max_it <maxit> - Sets maxit
3692: - -snes_max_funcs <maxf> - Sets maxf
3694: Level: intermediate
3696: .seealso: [](chapter_snes), `SNESolve()`, `SNES`, `SNESSetTrustRegionTolerance()`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`
3697: @*/
3698: PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
3699: {
3700: PetscFunctionBegin;
3708: if (abstol != (PetscReal)PETSC_DEFAULT) {
3709: PetscCheck(abstol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %g must be non-negative", (double)abstol);
3710: snes->abstol = abstol;
3711: }
3712: if (rtol != (PetscReal)PETSC_DEFAULT) {
3713: PetscCheck(rtol >= 0.0 && 1.0 > rtol, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Relative tolerance %g must be non-negative and less than 1.0", (double)rtol);
3714: snes->rtol = rtol;
3715: }
3716: if (stol != (PetscReal)PETSC_DEFAULT) {
3717: PetscCheck(stol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Step tolerance %g must be non-negative", (double)stol);
3718: snes->stol = stol;
3719: }
3720: if (maxit != PETSC_DEFAULT) {
3721: PetscCheck(maxit >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", maxit);
3722: snes->max_its = maxit;
3723: }
3724: if (maxf != PETSC_DEFAULT) {
3725: PetscCheck(maxf >= -1, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of function evaluations %" PetscInt_FMT " must be -1 or nonnegative", maxf);
3726: snes->max_funcs = maxf;
3727: }
3728: snes->tolerancesset = PETSC_TRUE;
3729: PetscFunctionReturn(PETSC_SUCCESS);
3730: }
3732: /*@
3733: SNESSetDivergenceTolerance - Sets the divergence tolerance used for the `SNES` divergence test.
3735: Logically Collective
3737: Input Parameters:
3738: + snes - the `SNES` context
3739: - divtol - the divergence tolerance. Use -1 to deactivate the test, default is 1e4
3741: Options Database Key:
3742: . -snes_divergence_tolerance <divtol> - Sets `divtol`
3744: Level: intermediate
3746: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESSetTolerances()`, `SNESGetDivergenceTolerance`
3747: @*/
3748: PetscErrorCode SNESSetDivergenceTolerance(SNES snes, PetscReal divtol)
3749: {
3750: PetscFunctionBegin;
3754: if (divtol != (PetscReal)PETSC_DEFAULT) {
3755: snes->divtol = divtol;
3756: } else {
3757: snes->divtol = 1.0e4;
3758: }
3759: PetscFunctionReturn(PETSC_SUCCESS);
3760: }
3762: /*@
3763: SNESGetTolerances - Gets various parameters used in convergence tests.
3765: Not Collective
3767: Input Parameters:
3768: + snes - the `SNES` context
3769: . atol - absolute convergence tolerance
3770: . rtol - relative convergence tolerance
3771: . stol - convergence tolerance in terms of the norm
3772: of the change in the solution between steps
3773: . maxit - maximum number of iterations
3774: - maxf - maximum number of function evaluations
3776: Level: intermediate
3778: Note:
3779: The user can specify `NULL` for any parameter that is not needed.
3781: .seealso: [](chapter_snes), `SNES`, `SNESSetTolerances()`
3782: @*/
3783: PetscErrorCode SNESGetTolerances(SNES snes, PetscReal *atol, PetscReal *rtol, PetscReal *stol, PetscInt *maxit, PetscInt *maxf)
3784: {
3785: PetscFunctionBegin;
3787: if (atol) *atol = snes->abstol;
3788: if (rtol) *rtol = snes->rtol;
3789: if (stol) *stol = snes->stol;
3790: if (maxit) *maxit = snes->max_its;
3791: if (maxf) *maxf = snes->max_funcs;
3792: PetscFunctionReturn(PETSC_SUCCESS);
3793: }
3795: /*@
3796: SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.
3798: Not Collective
3800: Input Parameters:
3801: + snes - the `SNES` context
3802: - divtol - divergence tolerance
3804: Level: intermediate
3806: .seealso: [](chapter_snes), `SNES`, `SNESSetDivergenceTolerance()`
3807: @*/
3808: PetscErrorCode SNESGetDivergenceTolerance(SNES snes, PetscReal *divtol)
3809: {
3810: PetscFunctionBegin;
3812: if (divtol) *divtol = snes->divtol;
3813: PetscFunctionReturn(PETSC_SUCCESS);
3814: }
3816: /*@
3817: SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.
3819: Logically Collective
3821: Input Parameters:
3822: + snes - the `SNES` context
3823: - tol - tolerance
3825: Options Database Key:
3826: . -snes_tr_tol <tol> - Sets tol
3828: Level: intermediate
3830: .seealso: [](chapter_snes), `SNES`, `SNESNEWTONTR`, `SNESSetTolerances()`
3831: @*/
3832: PetscErrorCode SNESSetTrustRegionTolerance(SNES snes, PetscReal tol)
3833: {
3834: PetscFunctionBegin;
3837: snes->deltatol = tol;
3838: PetscFunctionReturn(PETSC_SUCCESS);
3839: }
3841: PETSC_INTERN PetscErrorCode SNESMonitorRange_Private(SNES, PetscInt, PetscReal *);
3843: PetscErrorCode SNESMonitorLGRange(SNES snes, PetscInt n, PetscReal rnorm, void *monctx)
3844: {
3845: PetscDrawLG lg;
3846: PetscReal x, y, per;
3847: PetscViewer v = (PetscViewer)monctx;
3848: static PetscReal prev; /* should be in the context */
3849: PetscDraw draw;
3851: PetscFunctionBegin;
3853: PetscCall(PetscViewerDrawGetDrawLG(v, 0, &lg));
3854: if (!n) PetscCall(PetscDrawLGReset(lg));
3855: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3856: PetscCall(PetscDrawSetTitle(draw, "Residual norm"));
3857: x = (PetscReal)n;
3858: if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3859: else y = -15.0;
3860: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3861: if (n < 20 || !(n % 5) || snes->reason) {
3862: PetscCall(PetscDrawLGDraw(lg));
3863: PetscCall(PetscDrawLGSave(lg));
3864: }
3866: PetscCall(PetscViewerDrawGetDrawLG(v, 1, &lg));
3867: if (!n) PetscCall(PetscDrawLGReset(lg));
3868: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3869: PetscCall(PetscDrawSetTitle(draw, "% elemts > .2*max elemt"));
3870: PetscCall(SNESMonitorRange_Private(snes, n, &per));
3871: x = (PetscReal)n;
3872: y = 100.0 * per;
3873: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3874: if (n < 20 || !(n % 5) || snes->reason) {
3875: PetscCall(PetscDrawLGDraw(lg));
3876: PetscCall(PetscDrawLGSave(lg));
3877: }
3879: PetscCall(PetscViewerDrawGetDrawLG(v, 2, &lg));
3880: if (!n) {
3881: prev = rnorm;
3882: PetscCall(PetscDrawLGReset(lg));
3883: }
3884: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3885: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm"));
3886: x = (PetscReal)n;
3887: y = (prev - rnorm) / prev;
3888: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3889: if (n < 20 || !(n % 5) || snes->reason) {
3890: PetscCall(PetscDrawLGDraw(lg));
3891: PetscCall(PetscDrawLGSave(lg));
3892: }
3894: PetscCall(PetscViewerDrawGetDrawLG(v, 3, &lg));
3895: if (!n) PetscCall(PetscDrawLGReset(lg));
3896: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3897: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm*(% > .2 max)"));
3898: x = (PetscReal)n;
3899: y = (prev - rnorm) / (prev * per);
3900: if (n > 2) { /*skip initial crazy value */
3901: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3902: }
3903: if (n < 20 || !(n % 5) || snes->reason) {
3904: PetscCall(PetscDrawLGDraw(lg));
3905: PetscCall(PetscDrawLGSave(lg));
3906: }
3907: prev = rnorm;
3908: PetscFunctionReturn(PETSC_SUCCESS);
3909: }
3911: /*@
3912: SNESMonitor - runs the user provided monitor routines, if they exist
3914: Collective
3916: Input Parameters:
3917: + snes - nonlinear solver context obtained from `SNESCreate()`
3918: . iter - iteration number
3919: - rnorm - relative norm of the residual
3921: Level: developer
3923: Note:
3924: This routine is called by the `SNES` implementations.
3925: It does not typically need to be called by the user.
3927: .seealso: [](chapter_snes), `SNES`, `SNESMonitorSet()`
3928: @*/
3929: PetscErrorCode SNESMonitor(SNES snes, PetscInt iter, PetscReal rnorm)
3930: {
3931: PetscInt i, n = snes->numbermonitors;
3933: PetscFunctionBegin;
3934: PetscCall(VecLockReadPush(snes->vec_sol));
3935: for (i = 0; i < n; i++) PetscCall((*snes->monitor[i])(snes, iter, rnorm, snes->monitorcontext[i]));
3936: PetscCall(VecLockReadPop(snes->vec_sol));
3937: PetscFunctionReturn(PETSC_SUCCESS);
3938: }
3940: /* ------------ Routines to set performance monitoring options ----------- */
3942: /*MC
3943: SNESMonitorFunction - functional form passed to `SNESMonitorSet()` to monitor convergence of nonlinear solver
3945: Synopsis:
3946: #include <petscsnes.h>
3947: $ PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)
3949: Collective
3951: Input Parameters:
3952: + snes - the `SNES` context
3953: . its - iteration number
3954: . norm - 2-norm function value (may be estimated)
3955: - mctx - [optional] monitoring context
3957: Level: advanced
3959: .seealso: [](chapter_snes), `SNESMonitorSet()`, `SNESMonitorSet()`, `SNESMonitorGet()`
3960: M*/
3962: /*@C
3963: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3964: iteration of the nonlinear solver to display the iteration's
3965: progress.
3967: Logically Collective
3969: Input Parameters:
3970: + snes - the `SNES` context
3971: . f - the monitor function, for the calling sequence see `SNESMonitorFunction`
3972: . mctx - [optional] user-defined context for private data for the
3973: monitor routine (use `NULL` if no context is desired)
3974: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`)
3976: Options Database Keys:
3977: + -snes_monitor - sets `SNESMonitorDefault()`
3978: . -snes_monitor draw::draw_lg - sets line graph monitor,
3979: - -snes_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `SNESMonitorSet()`, but does not cancel those set via
3980: the options database.
3982: Level: intermediate
3984: Note:
3985: Several different monitoring routines may be set by calling
3986: `SNESMonitorSet()` multiple times; all will be called in the
3987: order in which they were set.
3989: Fortran Note:
3990: Only a single monitor function can be set for each `SNES` object
3992: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESMonitorDefault()`, `SNESMonitorCancel()`, `SNESMonitorFunction`
3993: @*/
3994: PetscErrorCode SNESMonitorSet(SNES snes, PetscErrorCode (*f)(SNES, PetscInt, PetscReal, void *), void *mctx, PetscErrorCode (*monitordestroy)(void **))
3995: {
3996: PetscInt i;
3997: PetscBool identical;
3999: PetscFunctionBegin;
4001: for (i = 0; i < snes->numbermonitors; i++) {
4002: PetscCall(PetscMonitorCompare((PetscErrorCode(*)(void))f, mctx, monitordestroy, (PetscErrorCode(*)(void))snes->monitor[i], snes->monitorcontext[i], snes->monitordestroy[i], &identical));
4003: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4004: }
4005: PetscCheck(snes->numbermonitors < MAXSNESMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
4006: snes->monitor[snes->numbermonitors] = f;
4007: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
4008: snes->monitorcontext[snes->numbermonitors++] = (void *)mctx;
4009: PetscFunctionReturn(PETSC_SUCCESS);
4010: }
4012: /*@
4013: SNESMonitorCancel - Clears all the monitor functions for a `SNES` object.
4015: Logically Collective
4017: Input Parameter:
4018: . snes - the `SNES` context
4020: Options Database Key:
4021: . -snes_monitor_cancel - cancels all monitors that have been hardwired
4022: into a code by calls to `SNESMonitorSet()`, but does not cancel those
4023: set via the options database
4025: Level: intermediate
4027: Note:
4028: There is no way to clear one specific monitor from a `SNES` object.
4030: .seealso: [](chapter_snes), `SNES`, `SNESMonitorGet()`, `SNESMonitorDefault()`, `SNESMonitorSet()`
4031: @*/
4032: PetscErrorCode SNESMonitorCancel(SNES snes)
4033: {
4034: PetscInt i;
4036: PetscFunctionBegin;
4038: for (i = 0; i < snes->numbermonitors; i++) {
4039: if (snes->monitordestroy[i]) PetscCall((*snes->monitordestroy[i])(&snes->monitorcontext[i]));
4040: }
4041: snes->numbermonitors = 0;
4042: PetscFunctionReturn(PETSC_SUCCESS);
4043: }
4045: /*MC
4046: SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver
4048: Synopsis:
4049: #include <petscsnes.h>
4050: $ PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)
4052: Collective
4054: Input Parameters:
4055: + snes - the `SNES` context
4056: . it - current iteration (0 is the first and is before any Newton step)
4057: . xnorm - 2-norm of current iterate
4058: . gnorm - 2-norm of current step
4059: . f - 2-norm of function
4060: - cctx - [optional] convergence context
4062: Output Parameter:
4063: . reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected
4065: Level: intermediate
4067: .seealso: [](chapter_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`, `SNESGetConvergenceTest()`
4068: M*/
4070: /*@C
4071: SNESSetConvergenceTest - Sets the function that is to be used
4072: to test for convergence of the nonlinear iterative solution.
4074: Logically Collective
4076: Input Parameters:
4077: + snes - the `SNES` context
4078: . `SNESConvergenceTestFunction` - routine to test for convergence
4079: . cctx - [optional] context for private data for the convergence routine (may be `NULL`)
4080: - destroy - [optional] destructor for the context (may be `NULL`; `PETSC_NULL_FUNCTION` in Fortran)
4082: Level: advanced
4084: .seealso: [](chapter_snes), `SNES`, `SNESConvergedDefault()`, `SNESConvergedSkip()`, `SNESConvergenceTestFunction`
4085: @*/
4086: PetscErrorCode SNESSetConvergenceTest(SNES snes, PetscErrorCode (*SNESConvergenceTestFunction)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *cctx, PetscErrorCode (*destroy)(void *))
4087: {
4088: PetscFunctionBegin;
4090: if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4091: if (snes->ops->convergeddestroy) PetscCall((*snes->ops->convergeddestroy)(snes->cnvP));
4092: snes->ops->converged = SNESConvergenceTestFunction;
4093: snes->ops->convergeddestroy = destroy;
4094: snes->cnvP = cctx;
4095: PetscFunctionReturn(PETSC_SUCCESS);
4096: }
4098: /*@
4099: SNESGetConvergedReason - Gets the reason the `SNES` iteration was stopped.
4101: Not Collective
4103: Input Parameter:
4104: . snes - the `SNES` context
4106: Output Parameter:
4107: . reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` for the individual convergence tests for complete lists
4109: Options Database Key:
4110: . -snes_converged_reason - prints the reason to standard out
4112: Level: intermediate
4114: Note:
4115: Should only be called after the call the `SNESSolve()` is complete, if it is called earlier it returns the value `SNES__CONVERGED_ITERATING`.
4117: .seealso: [](chapter_snes), `SNESSolve()`, `SNESSetConvergenceTest()`, `SNESSetConvergedReason()`, `SNESConvergedReason`, `SNESGetConvergedReasonString()`
4118: @*/
4119: PetscErrorCode SNESGetConvergedReason(SNES snes, SNESConvergedReason *reason)
4120: {
4121: PetscFunctionBegin;
4124: *reason = snes->reason;
4125: PetscFunctionReturn(PETSC_SUCCESS);
4126: }
4128: /*@C
4129: SNESGetConvergedReasonString - Return a human readable string for `SNESConvergedReason`
4131: Not Collective
4133: Input Parameter:
4134: . snes - the `SNES` context
4136: Output Parameter:
4137: . strreason - a human readable string that describes `SNES` converged reason
4139: Level: beginner
4141: .seealso: [](chapter_snes), `SNES`, `SNESGetConvergedReason()`
4142: @*/
4143: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char **strreason)
4144: {
4145: PetscFunctionBegin;
4148: *strreason = SNESConvergedReasons[snes->reason];
4149: PetscFunctionReturn(PETSC_SUCCESS);
4150: }
4152: /*@
4153: SNESSetConvergedReason - Sets the reason the `SNES` iteration was stopped.
4155: Not Collective
4157: Input Parameters:
4158: + snes - the `SNES` context
4159: - reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` or the
4160: manual pages for the individual convergence tests for complete lists
4162: Level: developer
4164: Developer Note:
4165: Called inside the various `SNESSolve()` implementations
4167: .seealso: [](chapter_snes), `SNESGetConvergedReason()`, `SNESSetConvergenceTest()`, `SNESConvergedReason`
4168: @*/
4169: PetscErrorCode SNESSetConvergedReason(SNES snes, SNESConvergedReason reason)
4170: {
4171: PetscFunctionBegin;
4173: snes->reason = reason;
4174: PetscFunctionReturn(PETSC_SUCCESS);
4175: }
4177: /*@
4178: SNESSetConvergenceHistory - Sets the array used to hold the convergence history.
4180: Logically Collective
4182: Input Parameters:
4183: + snes - iterative context obtained from `SNESCreate()`
4184: . a - array to hold history, this array will contain the function norms computed at each step
4185: . its - integer array holds the number of linear iterations for each solve.
4186: . na - size of a and its
4187: - reset - `PETSC_TRUE` indicates each new nonlinear solve resets the history counter to zero,
4188: else it continues storing new values for new nonlinear solves after the old ones
4190: Level: intermediate
4192: Notes:
4193: If 'a' and 'its' are `NULL` then space is allocated for the history. If 'na' `PETSC_DECIDE` or `PETSC_DEFAULT` then a
4194: default array of length 10000 is allocated.
4196: This routine is useful, e.g., when running a code for purposes
4197: of accurate performance monitoring, when no I/O should be done
4198: during the section of code that is being timed.
4200: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESGetConvergenceHistory()`
4201: @*/
4202: PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)
4203: {
4204: PetscFunctionBegin;
4208: if (!a) {
4209: if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
4210: PetscCall(PetscCalloc2(na, &a, na, &its));
4211: snes->conv_hist_alloc = PETSC_TRUE;
4212: }
4213: snes->conv_hist = a;
4214: snes->conv_hist_its = its;
4215: snes->conv_hist_max = (size_t)na;
4216: snes->conv_hist_len = 0;
4217: snes->conv_hist_reset = reset;
4218: PetscFunctionReturn(PETSC_SUCCESS);
4219: }
4221: #if defined(PETSC_HAVE_MATLAB)
4222: #include <engine.h> /* MATLAB include file */
4223: #include <mex.h> /* MATLAB include file */
4225: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4226: {
4227: mxArray *mat;
4228: PetscInt i;
4229: PetscReal *ar;
4231: mat = mxCreateDoubleMatrix(snes->conv_hist_len, 1, mxREAL);
4232: ar = (PetscReal *)mxGetData(mat);
4233: for (i = 0; i < snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4234: return mat;
4235: }
4236: #endif
4238: /*@C
4239: SNESGetConvergenceHistory - Gets the array used to hold the convergence history.
4241: Not Collective
4243: Input Parameter:
4244: . snes - iterative context obtained from `SNESCreate()`
4246: Output Parameters:
4247: + a - array to hold history, usually was set with `SNESSetConvergenceHistory()`
4248: . its - integer array holds the number of linear iterations (or
4249: negative if not converged) for each solve.
4250: - na - size of `a` and `its`
4252: Level: intermediate
4254: Note:
4255: This routine is useful, e.g., when running a code for purposes
4256: of accurate performance monitoring, when no I/O should be done
4257: during the section of code that is being timed.
4259: Fortran Note:
4260: The calling sequence for this routine in Fortran is
4261: .vb
4262: call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)
4263: .ve
4265: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESSetConvergenceHistory()`
4266: @*/
4267: PetscErrorCode SNESGetConvergenceHistory(SNES snes, PetscReal *a[], PetscInt *its[], PetscInt *na)
4268: {
4269: PetscFunctionBegin;
4271: if (a) *a = snes->conv_hist;
4272: if (its) *its = snes->conv_hist_its;
4273: if (na) *na = (PetscInt)snes->conv_hist_len;
4274: PetscFunctionReturn(PETSC_SUCCESS);
4275: }
4277: /*@C
4278: SNESSetUpdate - Sets the general-purpose update function called
4279: at the beginning of every iteration of the nonlinear solve. Specifically
4280: it is called just before the Jacobian is "evaluated".
4282: Logically Collective
4284: Input Parameters:
4285: + snes - The nonlinear solver context
4286: - func - The function
4288: Calling sequence of `func`:
4289: $ PetscErrorCode func(SNES snes, PetscInt step);
4290: + snes - the nonlinear solver context
4291: - step - The current step of the iteration
4293: Level: advanced
4295: Note:
4296: This is NOT what one uses to update the ghost points before a function evaluation, that should be done at the beginning of your function provided
4297: to `SNESSetFunction()`, or `SNESSetPicard()`
4298: This is not used by most users.
4300: There are a varity of function hooks one many set that are called at different stages of the nonlinear solution process, see the functions listed below.
4302: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESSetJacobian()`, `SNESSolve()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRSetPostCheck()`,
4303: `SNESMonitorSet()`, `SNESSetDivergenceTest()`
4304: @*/
4305: PetscErrorCode SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
4306: {
4307: PetscFunctionBegin;
4309: snes->ops->update = func;
4310: PetscFunctionReturn(PETSC_SUCCESS);
4311: }
4313: /*
4314: SNESScaleStep_Private - Scales a step so that its length is less than the
4315: positive parameter delta.
4317: Input Parameters:
4318: + snes - the `SNES` context
4319: . y - approximate solution of linear system
4320: . fnorm - 2-norm of current function
4321: - delta - trust region size
4323: Output Parameters:
4324: + gpnorm - predicted function norm at the new point, assuming local
4325: linearization. The value is zero if the step lies within the trust
4326: region, and exceeds zero otherwise.
4327: - ynorm - 2-norm of the step
4329: Level: developer
4331: Note:
4332: For non-trust region methods such as `SNESNEWTONLS`, the parameter delta
4333: is set to be the maximum allowable step size.
4334: */
4335: PetscErrorCode SNESScaleStep_Private(SNES snes, Vec y, PetscReal *fnorm, PetscReal *delta, PetscReal *gpnorm, PetscReal *ynorm)
4336: {
4337: PetscReal nrm;
4338: PetscScalar cnorm;
4340: PetscFunctionBegin;
4343: PetscCheckSameComm(snes, 1, y, 2);
4345: PetscCall(VecNorm(y, NORM_2, &nrm));
4346: if (nrm > *delta) {
4347: nrm = *delta / nrm;
4348: *gpnorm = (1.0 - nrm) * (*fnorm);
4349: cnorm = nrm;
4350: PetscCall(VecScale(y, cnorm));
4351: *ynorm = *delta;
4352: } else {
4353: *gpnorm = 0.0;
4354: *ynorm = nrm;
4355: }
4356: PetscFunctionReturn(PETSC_SUCCESS);
4357: }
4359: /*@C
4360: SNESConvergedReasonView - Displays the reason a `SNES` solve converged or diverged to a viewer
4362: Collective
4364: Parameter:
4365: + snes - iterative context obtained from `SNESCreate()`
4366: - viewer - the viewer to display the reason
4368: Options Database Keys:
4369: + -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4370: - -snes_converged_reason ::failed - only print reason and number of iterations when diverged
4372: Note:
4373: To change the format of the output call `PetscViewerPushFormat`(viewer,format) before this call. Use `PETSC_VIEWER_DEFAULT` for the default,
4374: use `PETSC_VIEWER_FAILED` to only display a reason if it fails.
4376: Level: beginner
4378: .seealso: [](chapter_snes), `SNESConvergedReason`, `PetscViewer`, `SNES`,
4379: `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`, `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`,
4380: `SNESConvergedReasonViewFromOptions()`,
4381: `PetscViewerPushFormat()`, `PetscViewerPopFormat()`
4382: @*/
4383: PetscErrorCode SNESConvergedReasonView(SNES snes, PetscViewer viewer)
4384: {
4385: PetscViewerFormat format;
4386: PetscBool isAscii;
4388: PetscFunctionBegin;
4389: if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4390: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isAscii));
4391: if (isAscii) {
4392: PetscCall(PetscViewerGetFormat(viewer, &format));
4393: PetscCall(PetscViewerASCIIAddTab(viewer, ((PetscObject)snes)->tablevel));
4394: if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4395: DM dm;
4396: Vec u;
4397: PetscDS prob;
4398: PetscInt Nf, f;
4399: PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4400: void **exactCtx;
4401: PetscReal error;
4403: PetscCall(SNESGetDM(snes, &dm));
4404: PetscCall(SNESGetSolution(snes, &u));
4405: PetscCall(DMGetDS(dm, &prob));
4406: PetscCall(PetscDSGetNumFields(prob, &Nf));
4407: PetscCall(PetscMalloc2(Nf, &exactSol, Nf, &exactCtx));
4408: for (f = 0; f < Nf; ++f) PetscCall(PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]));
4409: PetscCall(DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error));
4410: PetscCall(PetscFree2(exactSol, exactCtx));
4411: if (error < 1.0e-11) PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n"));
4412: else PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", (double)error));
4413: }
4414: if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4415: if (((PetscObject)snes)->prefix) {
4416: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve converged due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4417: } else {
4418: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve converged due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4419: }
4420: } else if (snes->reason <= 0) {
4421: if (((PetscObject)snes)->prefix) {
4422: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve did not converge due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4423: } else {
4424: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve did not converge due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4425: }
4426: }
4427: PetscCall(PetscViewerASCIISubtractTab(viewer, ((PetscObject)snes)->tablevel));
4428: }
4429: PetscFunctionReturn(PETSC_SUCCESS);
4430: }
4432: /*@C
4433: SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4434: end of the nonlinear solver to display the conver reason of the nonlinear solver.
4436: Logically Collective
4438: Input Parameters:
4439: + snes - the `SNES` context
4440: . f - the snes converged reason view function
4441: . vctx - [optional] user-defined context for private data for the
4442: snes converged reason view routine (use `NULL` if no context is desired)
4443: - reasonviewdestroy - [optional] routine that frees reasonview context (may be `NULL`)
4445: Options Database Keys:
4446: + -snes_converged_reason - sets a default `SNESConvergedReasonView()`
4447: - -snes_converged_reason_view_cancel - cancels all converged reason viewers that have
4448: been hardwired into a code by
4449: calls to `SNESConvergedReasonViewSet()`, but
4450: does not cancel those set via
4451: the options database.
4453: Level: intermediate
4455: Note:
4456: Several different converged reason view routines may be set by calling
4457: `SNESConvergedReasonViewSet()` multiple times; all will be called in the
4458: order in which they were set.
4460: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESConvergedReason`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`, `SNESConvergedReasonViewCancel()`
4461: @*/
4462: PetscErrorCode SNESConvergedReasonViewSet(SNES snes, PetscErrorCode (*f)(SNES, void *), void *vctx, PetscErrorCode (*reasonviewdestroy)(void **))
4463: {
4464: PetscInt i;
4465: PetscBool identical;
4467: PetscFunctionBegin;
4469: for (i = 0; i < snes->numberreasonviews; i++) {
4470: PetscCall(PetscMonitorCompare((PetscErrorCode(*)(void))f, vctx, reasonviewdestroy, (PetscErrorCode(*)(void))snes->reasonview[i], snes->reasonviewcontext[i], snes->reasonviewdestroy[i], &identical));
4471: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4472: }
4473: PetscCheck(snes->numberreasonviews < MAXSNESREASONVIEWS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many SNES reasonview set");
4474: snes->reasonview[snes->numberreasonviews] = f;
4475: snes->reasonviewdestroy[snes->numberreasonviews] = reasonviewdestroy;
4476: snes->reasonviewcontext[snes->numberreasonviews++] = (void *)vctx;
4477: PetscFunctionReturn(PETSC_SUCCESS);
4478: }
4480: /*@
4481: SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a `SNESConvergedReason` is to be viewed.
4482: All the user-provided convergedReasonView routines will be involved as well, if they exist.
4484: Collective
4486: Input Parameter:
4487: . snes - the `SNES` object
4489: Level: advanced
4491: .seealso: [](chapter_snes), `SNES`, `SNESConvergedReason`, `SNESConvergedReasonViewSet()`, `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`,
4492: `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`
4493: @*/
4494: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4495: {
4496: PetscViewer viewer;
4497: PetscBool flg;
4498: static PetscBool incall = PETSC_FALSE;
4499: PetscViewerFormat format;
4500: PetscInt i;
4502: PetscFunctionBegin;
4503: if (incall) PetscFunctionReturn(PETSC_SUCCESS);
4504: incall = PETSC_TRUE;
4506: /* All user-provided viewers are called first, if they exist. */
4507: for (i = 0; i < snes->numberreasonviews; i++) PetscCall((*snes->reasonview[i])(snes, snes->reasonviewcontext[i]));
4509: /* Call PETSc default routine if users ask for it */
4510: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_converged_reason", &viewer, &format, &flg));
4511: if (flg) {
4512: PetscCall(PetscViewerPushFormat(viewer, format));
4513: PetscCall(SNESConvergedReasonView(snes, viewer));
4514: PetscCall(PetscViewerPopFormat(viewer));
4515: PetscCall(PetscViewerDestroy(&viewer));
4516: }
4517: incall = PETSC_FALSE;
4518: PetscFunctionReturn(PETSC_SUCCESS);
4519: }
4521: /*@
4522: SNESSolve - Solves a nonlinear system F(x) = b.
4523: Call `SNESSolve()` after calling `SNESCreate()` and optional routines of the form `SNESSetXXX()`.
4525: Collective
4527: Input Parameters:
4528: + snes - the `SNES` context
4529: . b - the constant part of the equation F(x) = b, or `NULL` to use zero.
4530: - x - the solution vector.
4532: Level: beginner
4534: Note:
4535: The user should initialize the vector,x, with the initial guess
4536: for the nonlinear solve prior to calling `SNESSolve()`. In particular,
4537: to employ an initial guess of zero, the user should explicitly set
4538: this vector to zero by calling `VecSet()`.
4540: .seealso: [](chapter_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFunction()`, `SNESSetJacobian()`, `SNESSetGridSequence()`, `SNESGetSolution()`,
4541: `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRGetPreCheck()`, `SNESNewtonTRSetPostCheck()`, `SNESNewtonTRGetPostCheck()`,
4542: `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`
4543: @*/
4544: PetscErrorCode SNESSolve(SNES snes, Vec b, Vec x)
4545: {
4546: PetscBool flg;
4547: PetscInt grid;
4548: Vec xcreated = NULL;
4549: DM dm;
4551: PetscFunctionBegin;
4554: if (x) PetscCheckSameComm(snes, 1, x, 3);
4556: if (b) PetscCheckSameComm(snes, 1, b, 2);
4558: /* High level operations using the nonlinear solver */
4559: {
4560: PetscViewer viewer;
4561: PetscViewerFormat format;
4562: PetscInt num;
4563: PetscBool flg;
4564: static PetscBool incall = PETSC_FALSE;
4566: if (!incall) {
4567: /* Estimate the convergence rate of the discretization */
4568: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg));
4569: if (flg) {
4570: PetscConvEst conv;
4571: DM dm;
4572: PetscReal *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4573: PetscInt Nf;
4575: incall = PETSC_TRUE;
4576: PetscCall(SNESGetDM(snes, &dm));
4577: PetscCall(DMGetNumFields(dm, &Nf));
4578: PetscCall(PetscCalloc1(Nf, &alpha));
4579: PetscCall(PetscConvEstCreate(PetscObjectComm((PetscObject)snes), &conv));
4580: PetscCall(PetscConvEstSetSolver(conv, (PetscObject)snes));
4581: PetscCall(PetscConvEstSetFromOptions(conv));
4582: PetscCall(PetscConvEstSetUp(conv));
4583: PetscCall(PetscConvEstGetConvRate(conv, alpha));
4584: PetscCall(PetscViewerPushFormat(viewer, format));
4585: PetscCall(PetscConvEstRateView(conv, alpha, viewer));
4586: PetscCall(PetscViewerPopFormat(viewer));
4587: PetscCall(PetscViewerDestroy(&viewer));
4588: PetscCall(PetscConvEstDestroy(&conv));
4589: PetscCall(PetscFree(alpha));
4590: incall = PETSC_FALSE;
4591: }
4592: /* Adaptively refine the initial grid */
4593: num = 1;
4594: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_initial", &num, &flg));
4595: if (flg) {
4596: DMAdaptor adaptor;
4598: incall = PETSC_TRUE;
4599: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4600: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4601: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4602: PetscCall(DMAdaptorSetFromOptions(adaptor));
4603: PetscCall(DMAdaptorSetUp(adaptor));
4604: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x));
4605: PetscCall(DMAdaptorDestroy(&adaptor));
4606: incall = PETSC_FALSE;
4607: }
4608: /* Use grid sequencing to adapt */
4609: num = 0;
4610: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_sequence", &num, NULL));
4611: if (num) {
4612: DMAdaptor adaptor;
4614: incall = PETSC_TRUE;
4615: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4616: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4617: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4618: PetscCall(DMAdaptorSetFromOptions(adaptor));
4619: PetscCall(DMAdaptorSetUp(adaptor));
4620: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x));
4621: PetscCall(DMAdaptorDestroy(&adaptor));
4622: incall = PETSC_FALSE;
4623: }
4624: }
4625: }
4626: if (!x) x = snes->vec_sol;
4627: if (!x) {
4628: PetscCall(SNESGetDM(snes, &dm));
4629: PetscCall(DMCreateGlobalVector(dm, &xcreated));
4630: x = xcreated;
4631: }
4632: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view_pre"));
4634: for (grid = 0; grid < snes->gridsequence; grid++) PetscCall(PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4635: for (grid = 0; grid < snes->gridsequence + 1; grid++) {
4636: /* set solution vector */
4637: if (!grid) PetscCall(PetscObjectReference((PetscObject)x));
4638: PetscCall(VecDestroy(&snes->vec_sol));
4639: snes->vec_sol = x;
4640: PetscCall(SNESGetDM(snes, &dm));
4642: /* set affine vector if provided */
4643: if (b) PetscCall(PetscObjectReference((PetscObject)b));
4644: PetscCall(VecDestroy(&snes->vec_rhs));
4645: snes->vec_rhs = b;
4647: if (snes->vec_rhs) PetscCheck(snes->vec_func != snes->vec_rhs, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Right hand side vector cannot be function vector");
4648: PetscCheck(snes->vec_func != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be function vector");
4649: PetscCheck(snes->vec_rhs != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be right hand side vector");
4650: if (!snes->vec_sol_update /* && snes->vec_sol */) PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_sol_update));
4651: PetscCall(DMShellSetGlobalVector(dm, snes->vec_sol));
4652: PetscCall(SNESSetUp(snes));
4654: if (!grid) {
4655: if (snes->ops->computeinitialguess) PetscCallBack("SNES callback initial guess", (*snes->ops->computeinitialguess)(snes, snes->vec_sol, snes->initialguessP));
4656: }
4658: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4659: if (snes->counters_reset) {
4660: snes->nfuncs = 0;
4661: snes->linear_its = 0;
4662: snes->numFailures = 0;
4663: }
4665: PetscCall(PetscLogEventBegin(SNES_Solve, snes, 0, 0, 0));
4666: PetscUseTypeMethod(snes, solve);
4667: PetscCall(PetscLogEventEnd(SNES_Solve, snes, 0, 0, 0));
4668: PetscCheck(snes->reason, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Internal error, solver returned without setting converged reason");
4669: snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */
4671: if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4672: if (snes->lagpre_persist) snes->pre_iter += snes->iter;
4674: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_test_local_min", NULL, NULL, &flg));
4675: if (flg && !PetscPreLoadingOn) PetscCall(SNESTestLocalMin(snes));
4676: /* Call converged reason views. This may involve user-provided viewers as well */
4677: PetscCall(SNESConvergedReasonViewFromOptions(snes));
4679: if (snes->errorifnotconverged) PetscCheck(snes->reason >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_NOT_CONVERGED, "SNESSolve has not converged");
4680: if (snes->reason < 0) break;
4681: if (grid < snes->gridsequence) {
4682: DM fine;
4683: Vec xnew;
4684: Mat interp;
4686: PetscCall(DMRefine(snes->dm, PetscObjectComm((PetscObject)snes), &fine));
4687: PetscCheck(fine, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "DMRefine() did not perform any refinement, cannot continue grid sequencing");
4688: PetscCall(DMCreateInterpolation(snes->dm, fine, &interp, NULL));
4689: PetscCall(DMCreateGlobalVector(fine, &xnew));
4690: PetscCall(MatInterpolate(interp, x, xnew));
4691: PetscCall(DMInterpolate(snes->dm, interp, fine));
4692: PetscCall(MatDestroy(&interp));
4693: x = xnew;
4695: PetscCall(SNESReset(snes));
4696: PetscCall(SNESSetDM(snes, fine));
4697: PetscCall(SNESResetFromOptions(snes));
4698: PetscCall(DMDestroy(&fine));
4699: PetscCall(PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4700: }
4701: }
4702: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view"));
4703: PetscCall(VecViewFromOptions(snes->vec_sol, (PetscObject)snes, "-snes_view_solution"));
4704: PetscCall(DMMonitor(snes->dm));
4705: PetscCall(SNESMonitorPauseFinal_Internal(snes));
4707: PetscCall(VecDestroy(&xcreated));
4708: PetscCall(PetscObjectSAWsBlock((PetscObject)snes));
4709: PetscFunctionReturn(PETSC_SUCCESS);
4710: }
4712: /* --------- Internal routines for SNES Package --------- */
4714: /*@C
4715: SNESSetType - Sets the method for the nonlinear solver.
4717: Collective
4719: Input Parameters:
4720: + snes - the `SNES` context
4721: - type - a known method
4723: Options Database Key:
4724: . -snes_type <type> - Sets the method; use -help for a list
4725: of available methods (for instance, newtonls or newtontr)
4727: Level: intermediate
4729: Notes:
4730: See "petsc/include/petscsnes.h" for available methods (for instance)
4731: + `SNESNEWTONLS` - Newton's method with line search
4732: (systems of nonlinear equations)
4733: - `SNESNEWTONTR` - Newton's method with trust region
4734: (systems of nonlinear equations)
4736: Normally, it is best to use the `SNESSetFromOptions()` command and then
4737: set the `SNES` solver type from the options database rather than by using
4738: this routine. Using the options database provides the user with
4739: maximum flexibility in evaluating the many nonlinear solvers.
4740: The `SNESSetType()` routine is provided for those situations where it
4741: is necessary to set the nonlinear solver independently of the command
4742: line or options database. This might be the case, for example, when
4743: the choice of solver changes during the execution of the program,
4744: and the user's application is taking responsibility for choosing the
4745: appropriate method.
4747: Developer Note:
4748: `SNESRegister()` adds a constructor for a new `SNESType` to `SNESList`, `SNESSetType()` locates
4749: the constructor in that list and calls it to create the specific object.
4751: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESType`, `SNESCreate()`, `SNESDestroy()`, `SNESGetType()`, `SNESSetFromOptions()`
4752: @*/
4753: PetscErrorCode SNESSetType(SNES snes, SNESType type)
4754: {
4755: PetscBool match;
4756: PetscErrorCode (*r)(SNES);
4758: PetscFunctionBegin;
4762: PetscCall(PetscObjectTypeCompare((PetscObject)snes, type, &match));
4763: if (match) PetscFunctionReturn(PETSC_SUCCESS);
4765: PetscCall(PetscFunctionListFind(SNESList, type, &r));
4766: PetscCheck(r, PETSC_COMM_SELF, PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested SNES type %s", type);
4767: /* Destroy the previous private SNES context */
4768: PetscTryTypeMethod(snes, destroy);
4769: /* Reinitialize function pointers in SNESOps structure */
4770: snes->ops->setup = NULL;
4771: snes->ops->solve = NULL;
4772: snes->ops->view = NULL;
4773: snes->ops->setfromoptions = NULL;
4774: snes->ops->destroy = NULL;
4776: /* It may happen the user has customized the line search before calling SNESSetType */
4777: if (((PetscObject)snes)->type_name) PetscCall(SNESLineSearchDestroy(&snes->linesearch));
4779: /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4780: snes->setupcalled = PETSC_FALSE;
4782: PetscCall(PetscObjectChangeTypeName((PetscObject)snes, type));
4783: PetscCall((*r)(snes));
4784: PetscFunctionReturn(PETSC_SUCCESS);
4785: }
4787: /*@C
4788: SNESGetType - Gets the `SNES` method type and name (as a string).
4790: Not Collective
4792: Input Parameter:
4793: . snes - nonlinear solver context
4795: Output Parameter:
4796: . type - `SNES` method (a character string)
4798: Level: intermediate
4800: .seealso: [](chapter_snes), `SNESSetType()`, `SNESType`, `SNESSetFromOptions()`, `SNES`
4801: @*/
4802: PetscErrorCode SNESGetType(SNES snes, SNESType *type)
4803: {
4804: PetscFunctionBegin;
4807: *type = ((PetscObject)snes)->type_name;
4808: PetscFunctionReturn(PETSC_SUCCESS);
4809: }
4811: /*@
4812: SNESSetSolution - Sets the solution vector for use by the `SNES` routines.
4814: Logically Collective
4816: Input Parameters:
4817: + snes - the `SNES` context obtained from `SNESCreate()`
4818: - u - the solution vector
4820: Level: beginner
4822: .seealso: [](chapter_snes), `SNES`, `SNESSolve()`, `SNESGetSolution()`, `Vec`
4823: @*/
4824: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4825: {
4826: DM dm;
4828: PetscFunctionBegin;
4831: PetscCall(PetscObjectReference((PetscObject)u));
4832: PetscCall(VecDestroy(&snes->vec_sol));
4834: snes->vec_sol = u;
4836: PetscCall(SNESGetDM(snes, &dm));
4837: PetscCall(DMShellSetGlobalVector(dm, u));
4838: PetscFunctionReturn(PETSC_SUCCESS);
4839: }
4841: /*@
4842: SNESGetSolution - Returns the vector where the approximate solution is
4843: stored. This is the fine grid solution when using `SNESSetGridSequence()`.
4845: Not Collective, but x is parallel if snes is parallel
4847: Input Parameter:
4848: . snes - the `SNES` context
4850: Output Parameter:
4851: . x - the solution
4853: Level: intermediate
4855: .seealso: [](chapter_snes), `SNESSetSolution()`, `SNESSolve()`, `SNES`, `SNESGetSolutionUpdate()`, `SNESGetFunction()`
4856: @*/
4857: PetscErrorCode SNESGetSolution(SNES snes, Vec *x)
4858: {
4859: PetscFunctionBegin;
4862: *x = snes->vec_sol;
4863: PetscFunctionReturn(PETSC_SUCCESS);
4864: }
4866: /*@
4867: SNESGetSolutionUpdate - Returns the vector where the solution update is
4868: stored.
4870: Not Collective, but x is parallel if snes is parallel
4872: Input Parameter:
4873: . snes - the `SNES` context
4875: Output Parameter:
4876: . x - the solution update
4878: Level: advanced
4880: .seealso: [](chapter_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`
4881: @*/
4882: PetscErrorCode SNESGetSolutionUpdate(SNES snes, Vec *x)
4883: {
4884: PetscFunctionBegin;
4887: *x = snes->vec_sol_update;
4888: PetscFunctionReturn(PETSC_SUCCESS);
4889: }
4891: /*@C
4892: SNESGetFunction - Returns the function that defines the nonlinear system set with `SNESSetFunction()`
4894: Not Collective, but r is parallel if snes is parallel. Collective if r is requested, but has not been created yet.
4896: Input Parameter:
4897: . snes - the `SNES` context
4899: Output Parameters:
4900: + r - the vector that is used to store residuals (or `NULL` if you don't want it)
4901: . f - the function (or `NULL` if you don't want it); for calling sequence see `SNESFunction`
4902: - ctx - the function context (or `NULL` if you don't want it)
4904: Level: advanced
4906: Note:
4907: The vector `r` DOES NOT, in general, contain the current value of the `SNES` nonlinear function
4909: .seealso: [](chapter_snes), `SNES, `SNESSolve()`, `SNESSetFunction()`, `SNESGetSolution()`, `SNESFunction`
4910: @*/
4911: PetscErrorCode SNESGetFunction(SNES snes, Vec *r, PetscErrorCode (**f)(SNES, Vec, Vec, void *), void **ctx)
4912: {
4913: DM dm;
4915: PetscFunctionBegin;
4917: if (r) {
4918: if (!snes->vec_func) {
4919: if (snes->vec_rhs) {
4920: PetscCall(VecDuplicate(snes->vec_rhs, &snes->vec_func));
4921: } else if (snes->vec_sol) {
4922: PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_func));
4923: } else if (snes->dm) {
4924: PetscCall(DMCreateGlobalVector(snes->dm, &snes->vec_func));
4925: }
4926: }
4927: *r = snes->vec_func;
4928: }
4929: PetscCall(SNESGetDM(snes, &dm));
4930: PetscCall(DMSNESGetFunction(dm, f, ctx));
4931: PetscFunctionReturn(PETSC_SUCCESS);
4932: }
4934: /*@C
4935: SNESGetNGS - Returns the `SNESNGS` function and context set with `SNESSetNGS()`
4937: Input Parameter:
4938: . snes - the `SNES` context
4940: Output Parameters:
4941: + f - the function (or `NULL`) see `SNESNGSFunction` for details
4942: - ctx - the function context (or `NULL`)
4944: Level: advanced
4946: .seealso: [](chapter_snes), `SNESSetNGS()`, `SNESGetFunction()`
4947: @*/
4949: PetscErrorCode SNESGetNGS(SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void *), void **ctx)
4950: {
4951: DM dm;
4953: PetscFunctionBegin;
4955: PetscCall(SNESGetDM(snes, &dm));
4956: PetscCall(DMSNESGetNGS(dm, f, ctx));
4957: PetscFunctionReturn(PETSC_SUCCESS);
4958: }
4960: /*@C
4961: SNESSetOptionsPrefix - Sets the prefix used for searching for all
4962: `SNES` options in the database.
4964: Logically Collective
4966: Input Parameters:
4967: + snes - the `SNES` context
4968: - prefix - the prefix to prepend to all option names
4970: Level: advanced
4972: Note:
4973: A hyphen (-) must NOT be given at the beginning of the prefix name.
4974: The first character of all runtime options is AUTOMATICALLY the hyphen.
4976: .seealso: [](chapter_snes), `SNES`, `SNESSetFromOptions()`, `SNESAppendOptionsPrefix()`
4977: @*/
4978: PetscErrorCode SNESSetOptionsPrefix(SNES snes, const char prefix[])
4979: {
4980: PetscFunctionBegin;
4982: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes, prefix));
4983: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
4984: if (snes->linesearch) {
4985: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
4986: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch, prefix));
4987: }
4988: PetscCall(KSPSetOptionsPrefix(snes->ksp, prefix));
4989: PetscFunctionReturn(PETSC_SUCCESS);
4990: }
4992: /*@C
4993: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4994: `SNES` options in the database.
4996: Logically Collective
4998: Input Parameters:
4999: + snes - the `SNES` context
5000: - prefix - the prefix to prepend to all option names
5002: Level: advanced
5004: Note:
5005: A hyphen (-) must NOT be given at the beginning of the prefix name.
5006: The first character of all runtime options is AUTOMATICALLY the hyphen.
5008: .seealso: [](chapter_snes), `SNESGetOptionsPrefix()`, `SNESSetOptionsPrefix()`
5009: @*/
5010: PetscErrorCode SNESAppendOptionsPrefix(SNES snes, const char prefix[])
5011: {
5012: PetscFunctionBegin;
5014: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes, prefix));
5015: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5016: if (snes->linesearch) {
5017: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5018: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch, prefix));
5019: }
5020: PetscCall(KSPAppendOptionsPrefix(snes->ksp, prefix));
5021: PetscFunctionReturn(PETSC_SUCCESS);
5022: }
5024: /*@C
5025: SNESGetOptionsPrefix - Gets the prefix used for searching for all
5026: `SNES` options in the database.
5028: Not Collective
5030: Input Parameter:
5031: . snes - the `SNES` context
5033: Output Parameter:
5034: . prefix - pointer to the prefix string used
5036: Level: advanced
5038: Fortran Note:
5039: The user should pass in a string 'prefix' of
5040: sufficient length to hold the prefix.
5042: .seealso: [](chapter_snes), `SNES`, `SNESSetOptionsPrefix()`, `SNESAppendOptionsPrefix()`
5043: @*/
5044: PetscErrorCode SNESGetOptionsPrefix(SNES snes, const char *prefix[])
5045: {
5046: PetscFunctionBegin;
5048: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, prefix));
5049: PetscFunctionReturn(PETSC_SUCCESS);
5050: }
5052: /*@C
5053: SNESRegister - Adds a method to the nonlinear solver package.
5055: Not Collective
5057: Input Parameters:
5058: + sname - name of a new user-defined solver
5059: - function - routine to create method context
5061: Level: advanced
5063: Note:
5064: `SNESRegister()` may be called multiple times to add several user-defined solvers.
5066: Sample usage:
5067: .vb
5068: SNESRegister("my_solver",MySolverCreate);
5069: .ve
5071: Then, your solver can be chosen with the procedural interface via
5072: $ SNESSetType(snes,"my_solver")
5073: or at runtime via the option
5074: $ -snes_type my_solver
5076: .seealso: [](chapter_snes), `SNESRegisterAll()`, `SNESRegisterDestroy()`
5077: @*/
5078: PetscErrorCode SNESRegister(const char sname[], PetscErrorCode (*function)(SNES))
5079: {
5080: PetscFunctionBegin;
5081: PetscCall(SNESInitializePackage());
5082: PetscCall(PetscFunctionListAdd(&SNESList, sname, function));
5083: PetscFunctionReturn(PETSC_SUCCESS);
5084: }
5086: PetscErrorCode SNESTestLocalMin(SNES snes)
5087: {
5088: PetscInt N, i, j;
5089: Vec u, uh, fh;
5090: PetscScalar value;
5091: PetscReal norm;
5093: PetscFunctionBegin;
5094: PetscCall(SNESGetSolution(snes, &u));
5095: PetscCall(VecDuplicate(u, &uh));
5096: PetscCall(VecDuplicate(u, &fh));
5098: /* currently only works for sequential */
5099: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "Testing FormFunction() for local min\n"));
5100: PetscCall(VecGetSize(u, &N));
5101: for (i = 0; i < N; i++) {
5102: PetscCall(VecCopy(u, uh));
5103: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "i = %" PetscInt_FMT "\n", i));
5104: for (j = -10; j < 11; j++) {
5105: value = PetscSign(j) * PetscExpReal(PetscAbs(j) - 10.0);
5106: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5107: PetscCall(SNESComputeFunction(snes, uh, fh));
5108: PetscCall(VecNorm(fh, NORM_2, &norm));
5109: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), " j norm %" PetscInt_FMT " %18.16e\n", j, (double)norm));
5110: value = -value;
5111: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5112: }
5113: }
5114: PetscCall(VecDestroy(&uh));
5115: PetscCall(VecDestroy(&fh));
5116: PetscFunctionReturn(PETSC_SUCCESS);
5117: }
5119: /*@
5120: SNESKSPSetUseEW - Sets `SNES` to the use Eisenstat-Walker method for
5121: computing relative tolerance for linear solvers within an inexact
5122: Newton method.
5124: Logically Collective
5126: Input Parameters:
5127: + snes - `SNES` context
5128: - flag - `PETSC_TRUE` or `PETSC_FALSE`
5130: Options Database Keys:
5131: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5132: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
5133: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5134: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5135: . -snes_ksp_ew_gamma <gamma> - Sets gamma
5136: . -snes_ksp_ew_alpha <alpha> - Sets alpha
5137: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5138: - -snes_ksp_ew_threshold <threshold> - Sets threshold
5140: Level: advanced
5142: Note:
5143: The default is to use a constant relative tolerance for
5144: the inner linear solvers. Alternatively, one can use the
5145: Eisenstat-Walker method, where the relative convergence tolerance
5146: is reset at each Newton iteration according progress of the nonlinear
5147: solver.
5149: Reference:
5150: . - * S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an inexact Newton method", SISC 17 (1), pp.16-32, 1996.
5152: .seealso: [](chapter_snes), `KSP`, `SNES`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5153: @*/
5154: PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)
5155: {
5156: PetscFunctionBegin;
5159: snes->ksp_ewconv = flag;
5160: PetscFunctionReturn(PETSC_SUCCESS);
5161: }
5163: /*@
5164: SNESKSPGetUseEW - Gets if `SNES` is using Eisenstat-Walker method
5165: for computing relative tolerance for linear solvers within an
5166: inexact Newton method.
5168: Not Collective
5170: Input Parameter:
5171: . snes - `SNES` context
5173: Output Parameter:
5174: . flag - `PETSC_TRUE` or `PETSC_FALSE`
5176: Level: advanced
5178: .seealso: [](chapter_snes), `SNESKSPSetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5179: @*/
5180: PetscErrorCode SNESKSPGetUseEW(SNES snes, PetscBool *flag)
5181: {
5182: PetscFunctionBegin;
5185: *flag = snes->ksp_ewconv;
5186: PetscFunctionReturn(PETSC_SUCCESS);
5187: }
5189: /*@
5190: SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5191: convergence criteria for the linear solvers within an inexact
5192: Newton method.
5194: Logically Collective
5196: Input Parameters:
5197: + snes - `SNES` context
5198: . version - version 1, 2 (default is 2), 3 or 4
5199: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5200: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5201: . gamma - multiplicative factor for version 2 rtol computation
5202: (0 <= gamma2 <= 1)
5203: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5204: . alpha2 - power for safeguard
5205: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5207: Level: advanced
5209: Notes:
5210: Version 3 was contributed by Luis Chacon, June 2006.
5212: Use `PETSC_DEFAULT` to retain the default for any of the parameters.
5214: .seealso: [](chapter_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`
5215: @*/
5216: PetscErrorCode SNESKSPSetParametersEW(SNES snes, PetscInt version, PetscReal rtol_0, PetscReal rtol_max, PetscReal gamma, PetscReal alpha, PetscReal alpha2, PetscReal threshold)
5217: {
5218: SNESKSPEW *kctx;
5220: PetscFunctionBegin;
5222: kctx = (SNESKSPEW *)snes->kspconvctx;
5223: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5232: if (version != PETSC_DEFAULT) kctx->version = version;
5233: if (rtol_0 != (PetscReal)PETSC_DEFAULT) kctx->rtol_0 = rtol_0;
5234: if (rtol_max != (PetscReal)PETSC_DEFAULT) kctx->rtol_max = rtol_max;
5235: if (gamma != (PetscReal)PETSC_DEFAULT) kctx->gamma = gamma;
5236: if (alpha != (PetscReal)PETSC_DEFAULT) kctx->alpha = alpha;
5237: if (alpha2 != (PetscReal)PETSC_DEFAULT) kctx->alpha2 = alpha2;
5238: if (threshold != (PetscReal)PETSC_DEFAULT) kctx->threshold = threshold;
5240: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1 to 4 are supported: %" PetscInt_FMT, kctx->version);
5241: PetscCheck(kctx->rtol_0 >= 0.0 && kctx->rtol_0 < 1.0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "0.0 <= rtol_0 < 1.0: %g", (double)kctx->rtol_0);
5242: PetscCheck(kctx->rtol_max >= 0.0 && kctx->rtol_max < 1.0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "0.0 <= rtol_max (%g) < 1.0", (double)kctx->rtol_max);
5243: PetscCheck(kctx->gamma >= 0.0 && kctx->gamma <= 1.0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "0.0 <= gamma (%g) <= 1.0", (double)kctx->gamma);
5244: PetscCheck(kctx->alpha > 1.0 && kctx->alpha <= 2.0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "1.0 < alpha (%g) <= 2.0", (double)kctx->alpha);
5245: PetscCheck(kctx->threshold > 0.0 && kctx->threshold < 1.0, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "0.0 < threshold (%g) < 1.0", (double)kctx->threshold);
5246: PetscFunctionReturn(PETSC_SUCCESS);
5247: }
5249: /*@
5250: SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5251: convergence criteria for the linear solvers within an inexact
5252: Newton method.
5254: Not Collective
5256: Input Parameter:
5257: . snes - `SNES` context
5259: Output Parameters:
5260: + version - version 1, 2 (default is 2), 3 or 4
5261: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5262: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5263: . gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5264: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5265: . alpha2 - power for safeguard
5266: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5268: Level: advanced
5270: .seealso: [](chapter_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPSetParametersEW()`
5271: @*/
5272: PetscErrorCode SNESKSPGetParametersEW(SNES snes, PetscInt *version, PetscReal *rtol_0, PetscReal *rtol_max, PetscReal *gamma, PetscReal *alpha, PetscReal *alpha2, PetscReal *threshold)
5273: {
5274: SNESKSPEW *kctx;
5276: PetscFunctionBegin;
5278: kctx = (SNESKSPEW *)snes->kspconvctx;
5279: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5280: if (version) *version = kctx->version;
5281: if (rtol_0) *rtol_0 = kctx->rtol_0;
5282: if (rtol_max) *rtol_max = kctx->rtol_max;
5283: if (gamma) *gamma = kctx->gamma;
5284: if (alpha) *alpha = kctx->alpha;
5285: if (alpha2) *alpha2 = kctx->alpha2;
5286: if (threshold) *threshold = kctx->threshold;
5287: PetscFunctionReturn(PETSC_SUCCESS);
5288: }
5290: PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5291: {
5292: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5293: PetscReal rtol = PETSC_DEFAULT, stol;
5295: PetscFunctionBegin;
5296: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5297: if (!snes->iter) {
5298: rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5299: PetscCall(VecNorm(snes->vec_func, NORM_2, &kctx->norm_first));
5300: } else {
5301: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1-4 are supported: %" PetscInt_FMT, kctx->version);
5302: if (kctx->version == 1) {
5303: rtol = PetscAbsReal(snes->norm - kctx->lresid_last) / kctx->norm_last;
5304: stol = PetscPowReal(kctx->rtol_last, kctx->alpha2);
5305: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5306: } else if (kctx->version == 2) {
5307: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5308: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5309: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5310: } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5311: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5312: /* safeguard: avoid sharp decrease of rtol */
5313: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5314: stol = PetscMax(rtol, stol);
5315: rtol = PetscMin(kctx->rtol_0, stol);
5316: /* safeguard: avoid oversolving */
5317: stol = kctx->gamma * (kctx->norm_first * snes->rtol) / snes->norm;
5318: stol = PetscMax(rtol, stol);
5319: rtol = PetscMin(kctx->rtol_0, stol);
5320: } else /* if (kctx->version == 4) */ {
5321: /* H.-B. An et al. Journal of Computational and Applied Mathematics 200 (2007) 47-60 */
5322: PetscReal ared = PetscAbsReal(kctx->norm_last - snes->norm);
5323: PetscReal pred = PetscAbsReal(kctx->norm_last - kctx->lresid_last);
5324: PetscReal rk = ared / pred;
5325: if (rk < kctx->v4_p1) rtol = 1. - 2. * kctx->v4_p1;
5326: else if (rk < kctx->v4_p2) rtol = kctx->rtol_last;
5327: else if (rk < kctx->v4_p3) rtol = kctx->v4_m1 * kctx->rtol_last;
5328: else rtol = kctx->v4_m2 * kctx->rtol_last;
5330: if (kctx->rtol_last_2 > kctx->v4_m3 && kctx->rtol_last > kctx->v4_m3 && kctx->rk_last_2 < kctx->v4_p1 && kctx->rk_last < kctx->v4_p1) rtol = kctx->v4_m4 * kctx->rtol_last;
5331: kctx->rtol_last_2 = kctx->rtol_last;
5332: kctx->rk_last_2 = kctx->rk_last;
5333: kctx->rk_last = rk;
5334: }
5335: }
5336: /* safeguard: avoid rtol greater than rtol_max */
5337: rtol = PetscMin(rtol, kctx->rtol_max);
5338: PetscCall(KSPSetTolerances(ksp, rtol, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT));
5339: PetscCall(PetscInfo(snes, "iter %" PetscInt_FMT ", Eisenstat-Walker (version %" PetscInt_FMT ") KSP rtol=%g\n", snes->iter, kctx->version, (double)rtol));
5340: PetscFunctionReturn(PETSC_SUCCESS);
5341: }
5343: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5344: {
5345: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5346: PCSide pcside;
5347: Vec lres;
5349: PetscFunctionBegin;
5350: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5351: PetscCall(KSPGetTolerances(ksp, &kctx->rtol_last, NULL, NULL, NULL));
5352: kctx->norm_last = snes->norm;
5353: if (kctx->version == 1 || kctx->version == 4) {
5354: PC pc;
5355: PetscBool getRes;
5357: PetscCall(KSPGetPC(ksp, &pc));
5358: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCNONE, &getRes));
5359: if (!getRes) {
5360: KSPNormType normtype;
5362: PetscCall(KSPGetNormType(ksp, &normtype));
5363: getRes = (PetscBool)(normtype == KSP_NORM_UNPRECONDITIONED);
5364: }
5365: PetscCall(KSPGetPCSide(ksp, &pcside));
5366: if (pcside == PC_RIGHT || getRes) { /* KSP residual is true linear residual */
5367: PetscCall(KSPGetResidualNorm(ksp, &kctx->lresid_last));
5368: } else {
5369: /* KSP residual is preconditioned residual */
5370: /* compute true linear residual norm */
5371: Mat J;
5372: PetscCall(KSPGetOperators(ksp, &J, NULL));
5373: PetscCall(VecDuplicate(b, &lres));
5374: PetscCall(MatMult(J, x, lres));
5375: PetscCall(VecAYPX(lres, -1.0, b));
5376: PetscCall(VecNorm(lres, NORM_2, &kctx->lresid_last));
5377: PetscCall(VecDestroy(&lres));
5378: }
5379: }
5380: PetscFunctionReturn(PETSC_SUCCESS);
5381: }
5383: /*@
5384: SNESGetKSP - Returns the `KSP` context for a `SNES` solver.
5386: Not Collective, but if snes is parallel, then ksp is parallel
5388: Input Parameter:
5389: . snes - the `SNES` context
5391: Output Parameter:
5392: . ksp - the `KSP` context
5394: Level: beginner
5396: Notes:
5397: The user can then directly manipulate the `KSP` context to set various
5398: options, etc. Likewise, the user can then extract and manipulate the
5399: `PC` contexts as well.
5401: Some `SNESType`s do not use a `KSP` but a `KSP` is still returned by this function
5403: .seealso: [](chapter_snes), `SNES`, `KSP`, `PC`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
5404: @*/
5405: PetscErrorCode SNESGetKSP(SNES snes, KSP *ksp)
5406: {
5407: PetscFunctionBegin;
5411: if (!snes->ksp) {
5412: PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes), &snes->ksp));
5413: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->ksp, (PetscObject)snes, 1));
5415: PetscCall(KSPSetPreSolve(snes->ksp, (PetscErrorCode(*)(KSP, Vec, Vec, void *))KSPPreSolve_SNESEW, snes));
5416: PetscCall(KSPSetPostSolve(snes->ksp, (PetscErrorCode(*)(KSP, Vec, Vec, void *))KSPPostSolve_SNESEW, snes));
5418: PetscCall(KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes));
5419: PetscCall(PetscObjectSetOptions((PetscObject)snes->ksp, ((PetscObject)snes)->options));
5420: }
5421: *ksp = snes->ksp;
5422: PetscFunctionReturn(PETSC_SUCCESS);
5423: }
5425: #include <petsc/private/dmimpl.h>
5426: /*@
5427: SNESSetDM - Sets the `DM` that may be used by some nonlinear solvers or their underlying preconditioners
5429: Logically Collective
5431: Input Parameters:
5432: + snes - the nonlinear solver context
5433: - dm - the dm, cannot be `NULL`
5435: Level: intermediate
5437: Note:
5438: A `DM` can only be used for solving one problem at a time because information about the problem is stored on the `DM`,
5439: even when not using interfaces like `DMSNESSetFunction()`. Use `DMClone()` to get a distinct `DM` when solving different
5440: problems using the same function space.
5442: .seealso: [](chapter_snes), `DM`, `SNESGetDM()`, `KSPSetDM()`, `KSPGetDM()`
5443: @*/
5444: PetscErrorCode SNESSetDM(SNES snes, DM dm)
5445: {
5446: KSP ksp;
5447: DMSNES sdm;
5449: PetscFunctionBegin;
5452: PetscCall(PetscObjectReference((PetscObject)dm));
5453: if (snes->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
5454: if (snes->dm->dmsnes && !dm->dmsnes) {
5455: PetscCall(DMCopyDMSNES(snes->dm, dm));
5456: PetscCall(DMGetDMSNES(snes->dm, &sdm));
5457: if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5458: }
5459: PetscCall(DMCoarsenHookRemove(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
5460: PetscCall(DMDestroy(&snes->dm));
5461: }
5462: snes->dm = dm;
5463: snes->dmAuto = PETSC_FALSE;
5465: PetscCall(SNESGetKSP(snes, &ksp));
5466: PetscCall(KSPSetDM(ksp, dm));
5467: PetscCall(KSPSetDMActive(ksp, PETSC_FALSE));
5468: if (snes->npc) {
5469: PetscCall(SNESSetDM(snes->npc, snes->dm));
5470: PetscCall(SNESSetNPCSide(snes, snes->npcside));
5471: }
5472: PetscFunctionReturn(PETSC_SUCCESS);
5473: }
5475: /*@
5476: SNESGetDM - Gets the `DM` that may be used by some preconditioners
5478: Not Collective but dm obtained is parallel on snes
5480: Input Parameter:
5481: . snes - the preconditioner context
5483: Output Parameter:
5484: . dm - the dm
5486: Level: intermediate
5488: .seealso: [](chapter_snes), `DM`, `SNESSetDM()`, `KSPSetDM()`, `KSPGetDM()`
5489: @*/
5490: PetscErrorCode SNESGetDM(SNES snes, DM *dm)
5491: {
5492: PetscFunctionBegin;
5494: if (!snes->dm) {
5495: PetscCall(DMShellCreate(PetscObjectComm((PetscObject)snes), &snes->dm));
5496: snes->dmAuto = PETSC_TRUE;
5497: }
5498: *dm = snes->dm;
5499: PetscFunctionReturn(PETSC_SUCCESS);
5500: }
5502: /*@
5503: SNESSetNPC - Sets the nonlinear preconditioner to be used.
5505: Collective
5507: Input Parameters:
5508: + snes - iterative context obtained from `SNESCreate()`
5509: - npc - the preconditioner object
5511: Level: developer
5513: Notes:
5514: Use `SNESGetNPC()` to retrieve the preconditioner context (for example,
5515: to configure it using the API).
5517: Only some `SNESType` can use a nonlinear preconditioner
5519: .seealso: [](chapter_snes), `SNESNGS`, `SNESFAS`, `SNESGetNPC()`, `SNESHasNPC()`
5520: @*/
5521: PetscErrorCode SNESSetNPC(SNES snes, SNES npc)
5522: {
5523: PetscFunctionBegin;
5526: PetscCheckSameComm(snes, 1, npc, 2);
5527: PetscCall(PetscObjectReference((PetscObject)npc));
5528: PetscCall(SNESDestroy(&snes->npc));
5529: snes->npc = npc;
5530: PetscFunctionReturn(PETSC_SUCCESS);
5531: }
5533: /*@
5534: SNESGetNPC - Gets a nonlinear preconditioning solver SNES` to be used to precondition the original nonlinear solver.
5536: Not Collective; but any changes to the obtained the npc object must be applied collectively
5538: Input Parameter:
5539: . snes - iterative context obtained from `SNESCreate()`
5541: Output Parameter:
5542: . npc - preconditioner context
5544: Options Database Key:
5545: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5547: Level: developer
5549: Notes:
5550: If a `SNES` was previously set with `SNESSetNPC()` then that value is returned, otherwise a new `SNES` object is created.
5552: The (preconditioner) `SNES` returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5553: `SNES`
5555: .seealso: [](chapter_snes), `SNESSetNPC()`, `SNESHasNPC()`, `SNES`, `SNESCreate()`
5556: @*/
5557: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5558: {
5559: const char *optionsprefix;
5561: PetscFunctionBegin;
5564: if (!snes->npc) {
5565: void *ctx;
5567: PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &snes->npc));
5568: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->npc, (PetscObject)snes, 1));
5569: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5570: PetscCall(SNESSetOptionsPrefix(snes->npc, optionsprefix));
5571: PetscCall(SNESAppendOptionsPrefix(snes->npc, "npc_"));
5572: PetscCall(SNESGetApplicationContext(snes, &ctx));
5573: PetscCall(SNESSetApplicationContext(snes->npc, ctx));
5574: PetscCall(SNESSetCountersReset(snes->npc, PETSC_FALSE));
5575: }
5576: *pc = snes->npc;
5577: PetscFunctionReturn(PETSC_SUCCESS);
5578: }
5580: /*@
5581: SNESHasNPC - Returns whether a nonlinear preconditioner exists
5583: Not Collective
5585: Input Parameter:
5586: . snes - iterative context obtained from `SNESCreate()`
5588: Output Parameter:
5589: . has_npc - whether the `SNES` has an NPC or not
5591: Level: developer
5593: .seealso: [](chapter_snes), `SNESSetNPC()`, `SNESGetNPC()`
5594: @*/
5595: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5596: {
5597: PetscFunctionBegin;
5599: *has_npc = (PetscBool)(snes->npc ? PETSC_TRUE : PETSC_FALSE);
5600: PetscFunctionReturn(PETSC_SUCCESS);
5601: }
5603: /*@
5604: SNESSetNPCSide - Sets the preconditioning side.
5606: Logically Collective
5608: Input Parameter:
5609: . snes - iterative context obtained from `SNESCreate()`
5611: Output Parameter:
5612: . side - the preconditioning side, where side is one of
5613: .vb
5614: PC_LEFT - left preconditioning
5615: PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5616: .ve
5618: Options Database Key:
5619: . -snes_npc_side <right,left> - nonlinear preconditioner side
5621: Level: intermediate
5623: Note:
5624: `SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.
5626: .seealso: [](chapter_snes), `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`
5627: @*/
5628: PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
5629: {
5630: PetscFunctionBegin;
5633: if (side == PC_SIDE_DEFAULT) side = PC_RIGHT;
5634: PetscCheck((side == PC_LEFT) || (side == PC_RIGHT), PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Only PC_LEFT and PC_RIGHT are supported");
5635: snes->npcside = side;
5636: PetscFunctionReturn(PETSC_SUCCESS);
5637: }
5639: /*@
5640: SNESGetNPCSide - Gets the preconditioning side.
5642: Not Collective
5644: Input Parameter:
5645: . snes - iterative context obtained from `SNESCreate()`
5647: Output Parameter:
5648: . side - the preconditioning side, where side is one of
5649: .vb
5650: `PC_LEFT` - left preconditioning
5651: `PC_RIGHT` - right preconditioning (default for most nonlinear solvers)
5652: .ve
5654: Level: intermediate
5656: .seealso: [](chapter_snes), `SNES`, `SNESSetNPCSide()`, `KSPGetPCSide()`
5657: @*/
5658: PetscErrorCode SNESGetNPCSide(SNES snes, PCSide *side)
5659: {
5660: PetscFunctionBegin;
5663: *side = snes->npcside;
5664: PetscFunctionReturn(PETSC_SUCCESS);
5665: }
5667: /*@
5668: SNESSetLineSearch - Sets the linesearch on the `SNES` instance.
5670: Collective
5672: Input Parameters:
5673: + snes - iterative context obtained from `SNESCreate()`
5674: - linesearch - the linesearch object
5676: Level: developer
5678: Note:
5679: Use `SNESGetLineSearch()` to retrieve the preconditioner context (for example,
5680: to configure it using the API).
5682: .seealso: [](chapter_snes), `SNESGetLineSearch()`
5683: @*/
5684: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5685: {
5686: PetscFunctionBegin;
5689: PetscCheckSameComm(snes, 1, linesearch, 2);
5690: PetscCall(PetscObjectReference((PetscObject)linesearch));
5691: PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5693: snes->linesearch = linesearch;
5695: PetscFunctionReturn(PETSC_SUCCESS);
5696: }
5698: /*@
5699: SNESGetLineSearch - Returns the line search context set with `SNESSetLineSearch()`
5700: or creates a default line search instance associated with the `SNES` and returns it.
5702: Not Collective
5704: Input Parameter:
5705: . snes - iterative context obtained from `SNESCreate()`
5707: Output Parameter:
5708: . linesearch - linesearch context
5710: Level: beginner
5712: .seealso: [](chapter_snes), `SNESLineSearch`, `SNESSetLineSearch()`, `SNESLineSearchCreate()`
5713: @*/
5714: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5715: {
5716: const char *optionsprefix;
5718: PetscFunctionBegin;
5721: if (!snes->linesearch) {
5722: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5723: PetscCall(SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch));
5724: PetscCall(SNESLineSearchSetSNES(snes->linesearch, snes));
5725: PetscCall(SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix));
5726: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->linesearch, (PetscObject)snes, 1));
5727: }
5728: *linesearch = snes->linesearch;
5729: PetscFunctionReturn(PETSC_SUCCESS);
5730: }