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_NewtonALEval, 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: [](ch_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: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
58: @*/
59: PetscErrorCode SNESGetErrorIfNotConverged(SNES snes, PetscBool *flag)
60: {
61: PetscFunctionBegin;
63: PetscAssertPointer(flag, 2);
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: [](ch_snes), `SNES`, `SNESFAS`, `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: [](ch_snes), `SNES`, `SNESFAS`, `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: Notes:
128: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
130: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
132: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
133: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
135: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetJacobianDomainError()`, `SNESVISetVariableBounds()`,
136: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`
137: @*/
138: PetscErrorCode SNESSetFunctionDomainError(SNES snes)
139: {
140: PetscFunctionBegin;
142: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates input vector is not in the function domain");
143: snes->domainerror = PETSC_TRUE;
144: PetscFunctionReturn(PETSC_SUCCESS);
145: }
147: /*@
148: SNESSetJacobianDomainError - tells `SNES` that the function you provided to `SNESSetJacobian()` at the proposed step. For example there is a negative element transformation.
150: Logically Collective
152: Input Parameter:
153: . snes - the `SNES` context
155: Level: advanced
157: Notes:
158: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
160: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
162: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
163: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
165: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESVISetVariableBounds()`,
166: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`
167: @*/
168: PetscErrorCode SNESSetJacobianDomainError(SNES snes)
169: {
170: PetscFunctionBegin;
172: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates computeJacobian does not make sense");
173: snes->jacobiandomainerror = PETSC_TRUE;
174: PetscFunctionReturn(PETSC_SUCCESS);
175: }
177: /*@
178: SNESSetCheckJacobianDomainError - tells `SNESSolve()` whether to check if the user called `SNESSetJacobianDomainError()` Jacobian domain error after
179: each Jacobian evaluation. By default, it checks for the Jacobian domain error in the debug mode, and does not check it in the optimized mode.
181: Logically Collective
183: Input Parameters:
184: + snes - the `SNES` context
185: - flg - indicates if or not to check Jacobian domain error after each Jacobian evaluation
187: Level: advanced
189: Note:
190: Checks require one extra parallel synchronization for each Jacobian evaluation
192: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESGetCheckJacobianDomainError()`
193: @*/
194: PetscErrorCode SNESSetCheckJacobianDomainError(SNES snes, PetscBool flg)
195: {
196: PetscFunctionBegin;
198: snes->checkjacdomainerror = flg;
199: PetscFunctionReturn(PETSC_SUCCESS);
200: }
202: /*@
203: SNESGetCheckJacobianDomainError - Get an indicator whether or not `SNES` is checking Jacobian domain errors after each Jacobian evaluation.
205: Logically Collective
207: Input Parameter:
208: . snes - the `SNES` context
210: Output Parameter:
211: . flg - `PETSC_FALSE` indicates that it is not checking Jacobian domain errors after each Jacobian evaluation
213: Level: advanced
215: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESSetCheckJacobianDomainError()`
216: @*/
217: PetscErrorCode SNESGetCheckJacobianDomainError(SNES snes, PetscBool *flg)
218: {
219: PetscFunctionBegin;
221: PetscAssertPointer(flg, 2);
222: *flg = snes->checkjacdomainerror;
223: PetscFunctionReturn(PETSC_SUCCESS);
224: }
226: /*@
227: SNESGetFunctionDomainError - Gets the status of the domain error after a call to `SNESComputeFunction()`
229: Logically Collective
231: Input Parameter:
232: . snes - the `SNES` context
234: Output Parameter:
235: . domainerror - Set to `PETSC_TRUE` if there's a domain error; `PETSC_FALSE` otherwise.
237: Level: developer
239: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`
240: @*/
241: PetscErrorCode SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
242: {
243: PetscFunctionBegin;
245: PetscAssertPointer(domainerror, 2);
246: *domainerror = snes->domainerror;
247: PetscFunctionReturn(PETSC_SUCCESS);
248: }
250: /*@
251: SNESGetJacobianDomainError - Gets the status of the Jacobian domain error after a call to `SNESComputeJacobian()`
253: Logically Collective
255: Input Parameter:
256: . snes - the `SNES` context
258: Output Parameter:
259: . domainerror - Set to `PETSC_TRUE` if there's a Jacobian domain error; `PETSC_FALSE` otherwise.
261: Level: advanced
263: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`, `SNESGetFunctionDomainError()`
264: @*/
265: PetscErrorCode SNESGetJacobianDomainError(SNES snes, PetscBool *domainerror)
266: {
267: PetscFunctionBegin;
269: PetscAssertPointer(domainerror, 2);
270: *domainerror = snes->jacobiandomainerror;
271: PetscFunctionReturn(PETSC_SUCCESS);
272: }
274: /*@
275: SNESLoad - Loads a `SNES` that has been stored in `PETSCVIEWERBINARY` with `SNESView()`.
277: Collective
279: Input Parameters:
280: + snes - the newly loaded `SNES`, this needs to have been created with `SNESCreate()` or
281: some related function before a call to `SNESLoad()`.
282: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()`
284: Level: intermediate
286: Note:
287: The `SNESType` is determined by the data in the file, any type set into the `SNES` before this call is ignored.
289: .seealso: [](ch_snes), `SNES`, `PetscViewer`, `SNESCreate()`, `SNESType`, `PetscViewerBinaryOpen()`, `SNESView()`, `MatLoad()`, `VecLoad()`
290: @*/
291: PetscErrorCode SNESLoad(SNES snes, PetscViewer viewer)
292: {
293: PetscBool isbinary;
294: PetscInt classid;
295: char type[256];
296: KSP ksp;
297: DM dm;
298: DMSNES dmsnes;
300: PetscFunctionBegin;
303: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
304: PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
306: PetscCall(PetscViewerBinaryRead(viewer, &classid, 1, NULL, PETSC_INT));
307: PetscCheck(classid == SNES_FILE_CLASSID, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Not SNES next in file");
308: PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
309: PetscCall(SNESSetType(snes, type));
310: PetscTryTypeMethod(snes, load, viewer);
311: PetscCall(SNESGetDM(snes, &dm));
312: PetscCall(DMGetDMSNES(dm, &dmsnes));
313: PetscCall(DMSNESLoad(dmsnes, viewer));
314: PetscCall(SNESGetKSP(snes, &ksp));
315: PetscCall(KSPLoad(ksp, viewer));
316: PetscFunctionReturn(PETSC_SUCCESS);
317: }
319: #include <petscdraw.h>
320: #if defined(PETSC_HAVE_SAWS)
321: #include <petscviewersaws.h>
322: #endif
324: /*@
325: SNESViewFromOptions - View a `SNES` based on values in the options database
327: Collective
329: Input Parameters:
330: + A - the `SNES` context
331: . obj - Optional object that provides the options prefix for the checks
332: - name - command line option
334: Level: intermediate
336: .seealso: [](ch_snes), `SNES`, `SNESView`, `PetscObjectViewFromOptions()`, `SNESCreate()`
337: @*/
338: PetscErrorCode SNESViewFromOptions(SNES A, PetscObject obj, const char name[])
339: {
340: PetscFunctionBegin;
342: PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
343: PetscFunctionReturn(PETSC_SUCCESS);
344: }
346: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES, Vec, Mat, Mat, void *);
348: /*@
349: SNESView - Prints or visualizes the `SNES` data structure.
351: Collective
353: Input Parameters:
354: + snes - the `SNES` context
355: - viewer - the `PetscViewer`
357: Options Database Key:
358: . -snes_view - Calls `SNESView()` at end of `SNESSolve()`
360: Level: beginner
362: Notes:
363: The available visualization contexts include
364: + `PETSC_VIEWER_STDOUT_SELF` - standard output (default)
365: - `PETSC_VIEWER_STDOUT_WORLD` - synchronized standard
366: output where only the first processor opens
367: the file. All other processors send their
368: data to the first processor to print.
370: The available formats include
371: + `PETSC_VIEWER_DEFAULT` - standard output (default)
372: - `PETSC_VIEWER_ASCII_INFO_DETAIL` - more verbose output for `SNESNASM`
374: The user can open an alternative visualization context with
375: `PetscViewerASCIIOpen()` - output to a specified file.
377: In the debugger you can do "call `SNESView`(snes,0)" to display the `SNES` solver. (The same holds for any PETSc object viewer).
379: .seealso: [](ch_snes), `SNES`, `SNESLoad()`, `SNESCreate()`, `PetscViewerASCIIOpen()`
380: @*/
381: PetscErrorCode SNESView(SNES snes, PetscViewer viewer)
382: {
383: SNESKSPEW *kctx;
384: KSP ksp;
385: SNESLineSearch linesearch;
386: PetscBool iascii, isstring, isbinary, isdraw;
387: DMSNES dmsnes;
388: #if defined(PETSC_HAVE_SAWS)
389: PetscBool issaws;
390: #endif
392: PetscFunctionBegin;
394: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &viewer));
396: PetscCheckSameComm(snes, 1, viewer, 2);
398: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
399: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
400: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
401: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
402: #if defined(PETSC_HAVE_SAWS)
403: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
404: #endif
405: if (iascii) {
406: SNESNormSchedule normschedule;
407: DM dm;
408: SNESJacobianFn *cJ;
409: void *ctx;
410: const char *pre = "";
412: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)snes, viewer));
413: if (!snes->setupcalled) PetscCall(PetscViewerASCIIPrintf(viewer, " SNES has not been set up so information may be incomplete\n"));
414: if (snes->ops->view) {
415: PetscCall(PetscViewerASCIIPushTab(viewer));
416: PetscUseTypeMethod(snes, view, viewer);
417: PetscCall(PetscViewerASCIIPopTab(viewer));
418: }
419: if (snes->max_funcs == PETSC_UNLIMITED) {
420: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=unlimited\n", snes->max_its));
421: } else {
422: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=%" PetscInt_FMT "\n", snes->max_its, snes->max_funcs));
423: }
424: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%g, absolute=%g, solution=%g\n", (double)snes->rtol, (double)snes->abstol, (double)snes->stol));
425: if (snes->usesksp) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of linear solver iterations=%" PetscInt_FMT "\n", snes->linear_its));
426: PetscCall(PetscViewerASCIIPrintf(viewer, " total number of function evaluations=%" PetscInt_FMT "\n", snes->nfuncs));
427: PetscCall(SNESGetNormSchedule(snes, &normschedule));
428: if (normschedule > 0) PetscCall(PetscViewerASCIIPrintf(viewer, " norm schedule %s\n", SNESNormSchedules[normschedule]));
429: if (snes->gridsequence) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of grid sequence refinements=%" PetscInt_FMT "\n", snes->gridsequence));
430: if (snes->ksp_ewconv) {
431: kctx = (SNESKSPEW *)snes->kspconvctx;
432: if (kctx) {
433: PetscCall(PetscViewerASCIIPrintf(viewer, " Eisenstat-Walker computation of KSP relative tolerance (version %" PetscInt_FMT ")\n", kctx->version));
434: PetscCall(PetscViewerASCIIPrintf(viewer, " rtol_0=%g, rtol_max=%g, threshold=%g\n", (double)kctx->rtol_0, (double)kctx->rtol_max, (double)kctx->threshold));
435: PetscCall(PetscViewerASCIIPrintf(viewer, " gamma=%g, alpha=%g, alpha2=%g\n", (double)kctx->gamma, (double)kctx->alpha, (double)kctx->alpha2));
436: }
437: }
438: if (snes->lagpreconditioner == -1) {
439: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is never rebuilt\n"));
440: } else if (snes->lagpreconditioner > 1) {
441: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is rebuilt every %" PetscInt_FMT " new Jacobians\n", snes->lagpreconditioner));
442: }
443: if (snes->lagjacobian == -1) {
444: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is never rebuilt\n"));
445: } else if (snes->lagjacobian > 1) {
446: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is rebuilt every %" PetscInt_FMT " SNES iterations\n", snes->lagjacobian));
447: }
448: PetscCall(SNESGetDM(snes, &dm));
449: PetscCall(DMSNESGetJacobian(dm, &cJ, &ctx));
450: if (snes->mf_operator) {
451: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing\n"));
452: pre = "Preconditioning ";
453: }
454: if (cJ == SNESComputeJacobianDefault) {
455: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences one column at a time\n", pre));
456: } else if (cJ == SNESComputeJacobianDefaultColor) {
457: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences with coloring\n", pre));
458: /* it slightly breaks data encapsulation for access the DMDA information directly */
459: } else if (cJ == SNESComputeJacobian_DMDA) {
460: MatFDColoring fdcoloring;
461: PetscCall(PetscObjectQuery((PetscObject)dm, "DMDASNES_FDCOLORING", (PetscObject *)&fdcoloring));
462: if (fdcoloring) {
463: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using colored finite differences on a DMDA\n", pre));
464: } else {
465: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using a DMDA local Jacobian\n", pre));
466: }
467: } else if (snes->mf && !snes->mf_operator) {
468: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing, no explicit Jacobian\n"));
469: }
470: } else if (isstring) {
471: const char *type;
472: PetscCall(SNESGetType(snes, &type));
473: PetscCall(PetscViewerStringSPrintf(viewer, " SNESType: %-7.7s", type));
474: PetscTryTypeMethod(snes, view, viewer);
475: } else if (isbinary) {
476: PetscInt classid = SNES_FILE_CLASSID;
477: MPI_Comm comm;
478: PetscMPIInt rank;
479: char type[256];
481: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
482: PetscCallMPI(MPI_Comm_rank(comm, &rank));
483: if (rank == 0) {
484: PetscCall(PetscViewerBinaryWrite(viewer, &classid, 1, PETSC_INT));
485: PetscCall(PetscStrncpy(type, ((PetscObject)snes)->type_name, sizeof(type)));
486: PetscCall(PetscViewerBinaryWrite(viewer, type, sizeof(type), PETSC_CHAR));
487: }
488: PetscTryTypeMethod(snes, view, viewer);
489: } else if (isdraw) {
490: PetscDraw draw;
491: char str[36];
492: PetscReal x, y, bottom, h;
494: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
495: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
496: PetscCall(PetscStrncpy(str, "SNES: ", sizeof(str)));
497: PetscCall(PetscStrlcat(str, ((PetscObject)snes)->type_name, sizeof(str)));
498: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_BLUE, PETSC_DRAW_BLACK, str, NULL, &h));
499: bottom = y - h;
500: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
501: PetscTryTypeMethod(snes, view, viewer);
502: #if defined(PETSC_HAVE_SAWS)
503: } else if (issaws) {
504: PetscMPIInt rank;
505: const char *name;
507: PetscCall(PetscObjectGetName((PetscObject)snes, &name));
508: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
509: if (!((PetscObject)snes)->amsmem && rank == 0) {
510: char dir[1024];
512: PetscCall(PetscObjectViewSAWs((PetscObject)snes, viewer));
513: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/its", name));
514: PetscCallSAWs(SAWs_Register, (dir, &snes->iter, 1, SAWs_READ, SAWs_INT));
515: if (!snes->conv_hist) PetscCall(SNESSetConvergenceHistory(snes, NULL, NULL, PETSC_DECIDE, PETSC_TRUE));
516: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/conv_hist", name));
517: PetscCallSAWs(SAWs_Register, (dir, snes->conv_hist, 10, SAWs_READ, SAWs_DOUBLE));
518: }
519: #endif
520: }
521: if (snes->linesearch) {
522: PetscCall(SNESGetLineSearch(snes, &linesearch));
523: PetscCall(PetscViewerASCIIPushTab(viewer));
524: PetscCall(SNESLineSearchView(linesearch, viewer));
525: PetscCall(PetscViewerASCIIPopTab(viewer));
526: }
527: if (snes->npc && snes->usesnpc) {
528: PetscCall(PetscViewerASCIIPushTab(viewer));
529: PetscCall(SNESView(snes->npc, viewer));
530: PetscCall(PetscViewerASCIIPopTab(viewer));
531: }
532: PetscCall(PetscViewerASCIIPushTab(viewer));
533: PetscCall(DMGetDMSNES(snes->dm, &dmsnes));
534: PetscCall(DMSNESView(dmsnes, viewer));
535: PetscCall(PetscViewerASCIIPopTab(viewer));
536: if (snes->usesksp) {
537: PetscCall(SNESGetKSP(snes, &ksp));
538: PetscCall(PetscViewerASCIIPushTab(viewer));
539: PetscCall(KSPView(ksp, viewer));
540: PetscCall(PetscViewerASCIIPopTab(viewer));
541: }
542: if (isdraw) {
543: PetscDraw draw;
544: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
545: PetscCall(PetscDrawPopCurrentPoint(draw));
546: }
547: PetscFunctionReturn(PETSC_SUCCESS);
548: }
550: /*
551: We retain a list of functions that also take SNES command
552: line options. These are called at the end SNESSetFromOptions()
553: */
554: #define MAXSETFROMOPTIONS 5
555: static PetscInt numberofsetfromoptions;
556: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);
558: /*@C
559: SNESAddOptionsChecker - Adds an additional function to check for `SNES` options.
561: Not Collective
563: Input Parameter:
564: . snescheck - function that checks for options
566: Calling sequence of `snescheck`:
567: . snes - the `SNES` object for which it is checking options
569: Level: developer
571: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`
572: @*/
573: PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES snes))
574: {
575: PetscFunctionBegin;
576: PetscCheck(numberofsetfromoptions < MAXSETFROMOPTIONS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %d allowed", MAXSETFROMOPTIONS);
577: othersetfromoptions[numberofsetfromoptions++] = snescheck;
578: PetscFunctionReturn(PETSC_SUCCESS);
579: }
581: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
582: {
583: Mat J;
584: MatNullSpace nullsp;
586: PetscFunctionBegin;
589: if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
590: Mat A = snes->jacobian, B = snes->jacobian_pre;
591: PetscCall(MatCreateVecs(A ? A : B, NULL, &snes->vec_func));
592: }
594: PetscCheck(version == 1 || version == 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator routines, only version 1 and 2");
595: if (version == 1) {
596: PetscCall(MatCreateSNESMF(snes, &J));
597: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
598: PetscCall(MatSetFromOptions(J));
599: /* TODO: the version 2 code should be merged into the MatCreateSNESMF() and MatCreateMFFD() infrastructure and then removed */
600: } else /* if (version == 2) */ {
601: PetscCheck(snes->vec_func, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "SNESSetFunction() must be called first");
602: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
603: PetscCall(MatCreateSNESMFMore(snes, snes->vec_func, &J));
604: #else
605: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "matrix-free operator routines (version 2)");
606: #endif
607: }
609: /* attach any user provided null space that was on Amat to the newly created matrix-free matrix */
610: if (snes->jacobian) {
611: PetscCall(MatGetNullSpace(snes->jacobian, &nullsp));
612: if (nullsp) PetscCall(MatSetNullSpace(J, nullsp));
613: }
615: PetscCall(PetscInfo(snes, "Setting default matrix-free operator routines (version %" PetscInt_FMT ")\n", version));
616: if (hasOperator) {
617: /* This version replaces the user provided Jacobian matrix with a
618: matrix-free version but still employs the user-provided matrix used for computing the preconditioner. */
619: PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
620: } else {
621: /* This version replaces both the user-provided Jacobian and the user-
622: provided preconditioner Jacobian with the default matrix-free version. */
623: if (snes->npcside == PC_LEFT && snes->npc) {
624: if (!snes->jacobian) PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
625: } else {
626: KSP ksp;
627: PC pc;
628: PetscBool match;
630: PetscCall(SNESSetJacobian(snes, J, J, MatMFFDComputeJacobian, NULL));
631: /* Force no preconditioner */
632: PetscCall(SNESGetKSP(snes, &ksp));
633: PetscCall(KSPGetPC(ksp, &pc));
634: PetscCall(PetscObjectTypeCompareAny((PetscObject)pc, &match, PCSHELL, PCH2OPUS, ""));
635: if (!match) {
636: PetscCall(PetscInfo(snes, "Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n"));
637: PetscCall(PCSetType(pc, PCNONE));
638: }
639: }
640: }
641: PetscCall(MatDestroy(&J));
642: PetscFunctionReturn(PETSC_SUCCESS);
643: }
645: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine, Mat Restrict, Vec Rscale, Mat Inject, DM dmcoarse, void *ctx)
646: {
647: SNES snes = (SNES)ctx;
648: Vec Xfine, Xfine_named = NULL, Xcoarse;
650: PetscFunctionBegin;
651: if (PetscLogPrintInfo) {
652: PetscInt finelevel, coarselevel, fineclevel, coarseclevel;
653: PetscCall(DMGetRefineLevel(dmfine, &finelevel));
654: PetscCall(DMGetCoarsenLevel(dmfine, &fineclevel));
655: PetscCall(DMGetRefineLevel(dmcoarse, &coarselevel));
656: PetscCall(DMGetCoarsenLevel(dmcoarse, &coarseclevel));
657: PetscCall(PetscInfo(dmfine, "Restricting SNES solution vector from level %" PetscInt_FMT "-%" PetscInt_FMT " to level %" PetscInt_FMT "-%" PetscInt_FMT "\n", finelevel, fineclevel, coarselevel, coarseclevel));
658: }
659: if (dmfine == snes->dm) Xfine = snes->vec_sol;
660: else {
661: PetscCall(DMGetNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
662: Xfine = Xfine_named;
663: }
664: PetscCall(DMGetNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
665: if (Inject) {
666: PetscCall(MatRestrict(Inject, Xfine, Xcoarse));
667: } else {
668: PetscCall(MatRestrict(Restrict, Xfine, Xcoarse));
669: PetscCall(VecPointwiseMult(Xcoarse, Xcoarse, Rscale));
670: }
671: PetscCall(DMRestoreNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
672: if (Xfine_named) PetscCall(DMRestoreNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
673: PetscFunctionReturn(PETSC_SUCCESS);
674: }
676: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm, DM dmc, void *ctx)
677: {
678: PetscFunctionBegin;
679: PetscCall(DMCoarsenHookAdd(dmc, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, ctx));
680: PetscFunctionReturn(PETSC_SUCCESS);
681: }
683: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
684: * safely call SNESGetDM() in their residual evaluation routine. */
685: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp, Mat A, Mat B, void *ctx)
686: {
687: SNES snes = (SNES)ctx;
688: DMSNES sdm;
689: Vec X, Xnamed = NULL;
690: DM dmsave;
691: void *ctxsave;
692: SNESJacobianFn *jac = NULL;
694: PetscFunctionBegin;
695: dmsave = snes->dm;
696: PetscCall(KSPGetDM(ksp, &snes->dm));
697: if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
698: else {
699: PetscBool has;
701: /* We are on a coarser level, this vec was initialized using a DM restrict hook */
702: PetscCall(DMHasNamedGlobalVector(snes->dm, "SNESVecSol", &has));
703: PetscCheck(has, PetscObjectComm((PetscObject)snes->dm), PETSC_ERR_PLIB, "Missing SNESVecSol");
704: PetscCall(DMGetNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
705: X = Xnamed;
706: PetscCall(SNESGetJacobian(snes, NULL, NULL, &jac, &ctxsave));
707: /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
708: if (jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, SNESComputeJacobianDefaultColor, NULL));
709: }
711: /* Compute the operators */
712: PetscCall(DMGetDMSNES(snes->dm, &sdm));
713: if (Xnamed && sdm->ops->computefunction) {
714: /* The SNES contract with the user is that ComputeFunction is always called before ComputeJacobian.
715: We make sure of this here. Disable affine shift since it is for the finest level */
716: Vec F, saverhs = snes->vec_rhs;
718: snes->vec_rhs = NULL;
719: PetscCall(DMGetGlobalVector(snes->dm, &F));
720: PetscCall(SNESComputeFunction(snes, X, F));
721: PetscCall(DMRestoreGlobalVector(snes->dm, &F));
722: snes->vec_rhs = saverhs;
723: snes->nfuncs--; /* Do not log coarser level evaluations */
724: }
725: /* Make sure KSP DM has the Jacobian computation routine */
726: if (!sdm->ops->computejacobian) PetscCall(DMCopyDMSNES(dmsave, snes->dm));
727: PetscCall(SNESComputeJacobian(snes, X, A, B));
729: /* Put the previous context back */
730: if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, jac, ctxsave));
732: if (Xnamed) PetscCall(DMRestoreNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
733: snes->dm = dmsave;
734: PetscFunctionReturn(PETSC_SUCCESS);
735: }
737: /*@
738: SNESSetUpMatrices - ensures that matrices are available for `SNES` Newton-like methods, this is called by `SNESSetUp_XXX()`
740: Collective
742: Input Parameter:
743: . snes - `SNES` object to configure
745: Level: developer
747: Note:
748: If the matrices do not yet exist it attempts to create them based on options previously set for the `SNES` such as `-snes_mf`
750: Developer Note:
751: The functionality of this routine overlaps in a confusing way with the functionality of `SNESSetUpMatrixFree_Private()` which is called by
752: `SNESSetUp()` but sometimes `SNESSetUpMatrices()` is called without `SNESSetUp()` being called. A refactorization to simplify the
753: logic that handles the matrix-free case is desirable.
755: .seealso: [](ch_snes), `SNES`, `SNESSetUp()`
756: @*/
757: PetscErrorCode SNESSetUpMatrices(SNES snes)
758: {
759: DM dm;
760: DMSNES sdm;
762: PetscFunctionBegin;
763: PetscCall(SNESGetDM(snes, &dm));
764: PetscCall(DMGetDMSNES(dm, &sdm));
765: if (!snes->jacobian && snes->mf && !snes->mf_operator && !snes->jacobian_pre) {
766: Mat J;
767: void *functx;
768: PetscCall(MatCreateSNESMF(snes, &J));
769: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
770: PetscCall(MatSetFromOptions(J));
771: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
772: PetscCall(SNESSetJacobian(snes, J, J, NULL, NULL));
773: PetscCall(MatDestroy(&J));
774: } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
775: Mat J, B;
776: PetscCall(MatCreateSNESMF(snes, &J));
777: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
778: PetscCall(MatSetFromOptions(J));
779: PetscCall(DMCreateMatrix(snes->dm, &B));
780: /* sdm->computejacobian was already set to reach here */
781: PetscCall(SNESSetJacobian(snes, J, B, NULL, NULL));
782: PetscCall(MatDestroy(&J));
783: PetscCall(MatDestroy(&B));
784: } else if (!snes->jacobian_pre) {
785: PetscDS prob;
786: Mat J, B;
787: PetscBool hasPrec = PETSC_FALSE;
789: J = snes->jacobian;
790: PetscCall(DMGetDS(dm, &prob));
791: if (prob) PetscCall(PetscDSHasJacobianPreconditioner(prob, &hasPrec));
792: if (J) PetscCall(PetscObjectReference((PetscObject)J));
793: else if (hasPrec) PetscCall(DMCreateMatrix(snes->dm, &J));
794: PetscCall(DMCreateMatrix(snes->dm, &B));
795: PetscCall(SNESSetJacobian(snes, J ? J : B, B, NULL, NULL));
796: PetscCall(MatDestroy(&J));
797: PetscCall(MatDestroy(&B));
798: }
799: {
800: KSP ksp;
801: PetscCall(SNESGetKSP(snes, &ksp));
802: PetscCall(KSPSetComputeOperators(ksp, KSPComputeOperators_SNES, snes));
803: PetscCall(DMCoarsenHookAdd(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
804: }
805: PetscFunctionReturn(PETSC_SUCCESS);
806: }
808: PETSC_EXTERN PetscErrorCode PetscMonitorPauseFinal_Internal(PetscInt, void *);
810: static PetscErrorCode SNESMonitorPauseFinal_Internal(SNES snes)
811: {
812: PetscFunctionBegin;
813: if (!snes->pauseFinal) PetscFunctionReturn(PETSC_SUCCESS);
814: PetscCall(PetscMonitorPauseFinal_Internal(snes->numbermonitors, snes->monitorcontext));
815: PetscFunctionReturn(PETSC_SUCCESS);
816: }
818: /*@C
819: SNESMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user
821: Collective
823: Input Parameters:
824: + snes - `SNES` object you wish to monitor
825: . name - the monitor type one is seeking
826: . help - message indicating what monitoring is done
827: . manual - manual page for the monitor
828: . monitor - the monitor function, this must use a `PetscViewerFormat` as its context
829: - 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
831: Calling sequence of `monitor`:
832: + snes - the nonlinear solver context
833: . it - the current iteration
834: . r - the current function norm
835: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
837: Calling sequence of `monitorsetup`:
838: + snes - the nonlinear solver context
839: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
841: Options Database Key:
842: . -name - trigger the use of this monitor in `SNESSetFromOptions()`
844: Level: advanced
846: .seealso: [](ch_snes), `PetscOptionsCreateViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
847: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`
848: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
849: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
850: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
851: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
852: `PetscOptionsFList()`, `PetscOptionsEList()`
853: @*/
854: PetscErrorCode SNESMonitorSetFromOptions(SNES snes, const char name[], const char help[], const char manual[], PetscErrorCode (*monitor)(SNES snes, PetscInt it, PetscReal r, PetscViewerAndFormat *vf), PetscErrorCode (*monitorsetup)(SNES snes, PetscViewerAndFormat *vf))
855: {
856: PetscViewer viewer;
857: PetscViewerFormat format;
858: PetscBool flg;
860: PetscFunctionBegin;
861: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, name, &viewer, &format, &flg));
862: if (flg) {
863: PetscViewerAndFormat *vf;
864: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
865: PetscCall(PetscViewerDestroy(&viewer));
866: if (monitorsetup) PetscCall((*monitorsetup)(snes, vf));
867: PetscCall(SNESMonitorSet(snes, (PetscErrorCode (*)(SNES, PetscInt, PetscReal, void *))monitor, vf, (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy));
868: }
869: PetscFunctionReturn(PETSC_SUCCESS);
870: }
872: PetscErrorCode SNESEWSetFromOptions_Private(SNESKSPEW *kctx, PetscBool print_api, MPI_Comm comm, const char *prefix)
873: {
874: const char *api = print_api ? "SNESKSPSetParametersEW" : NULL;
876: PetscFunctionBegin;
877: PetscOptionsBegin(comm, prefix, "Eisenstat and Walker type forcing options", "KSP");
878: PetscCall(PetscOptionsInt("-ksp_ew_version", "Version 1, 2 or 3", api, kctx->version, &kctx->version, NULL));
879: PetscCall(PetscOptionsReal("-ksp_ew_rtol0", "0 <= rtol0 < 1", api, kctx->rtol_0, &kctx->rtol_0, NULL));
880: kctx->rtol_max = PetscMax(kctx->rtol_0, kctx->rtol_max);
881: PetscCall(PetscOptionsReal("-ksp_ew_rtolmax", "0 <= rtolmax < 1", api, kctx->rtol_max, &kctx->rtol_max, NULL));
882: PetscCall(PetscOptionsReal("-ksp_ew_gamma", "0 <= gamma <= 1", api, kctx->gamma, &kctx->gamma, NULL));
883: PetscCall(PetscOptionsReal("-ksp_ew_alpha", "1 < alpha <= 2", api, kctx->alpha, &kctx->alpha, NULL));
884: PetscCall(PetscOptionsReal("-ksp_ew_alpha2", "alpha2", NULL, kctx->alpha2, &kctx->alpha2, NULL));
885: PetscCall(PetscOptionsReal("-ksp_ew_threshold", "0 < threshold < 1", api, kctx->threshold, &kctx->threshold, NULL));
886: PetscCall(PetscOptionsReal("-ksp_ew_v4_p1", "p1", NULL, kctx->v4_p1, &kctx->v4_p1, NULL));
887: PetscCall(PetscOptionsReal("-ksp_ew_v4_p2", "p2", NULL, kctx->v4_p2, &kctx->v4_p2, NULL));
888: PetscCall(PetscOptionsReal("-ksp_ew_v4_p3", "p3", NULL, kctx->v4_p3, &kctx->v4_p3, NULL));
889: PetscCall(PetscOptionsReal("-ksp_ew_v4_m1", "Scaling when rk-1 in [p2,p3)", NULL, kctx->v4_m1, &kctx->v4_m1, NULL));
890: PetscCall(PetscOptionsReal("-ksp_ew_v4_m2", "Scaling when rk-1 in [p3,+infty)", NULL, kctx->v4_m2, &kctx->v4_m2, NULL));
891: PetscCall(PetscOptionsReal("-ksp_ew_v4_m3", "Threshold for successive rtol (0.1 in Eq.7)", NULL, kctx->v4_m3, &kctx->v4_m3, NULL));
892: PetscCall(PetscOptionsReal("-ksp_ew_v4_m4", "Adaptation scaling (0.5 in Eq.7)", NULL, kctx->v4_m4, &kctx->v4_m4, NULL));
893: PetscOptionsEnd();
894: PetscFunctionReturn(PETSC_SUCCESS);
895: }
897: /*@
898: SNESSetFromOptions - Sets various `SNES` and `KSP` parameters from user options.
900: Collective
902: Input Parameter:
903: . snes - the `SNES` context
905: Options Database Keys:
906: + -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, `SNESType` for complete list
907: . -snes_rtol <rtol> - relative decrease in tolerance norm from initial
908: . -snes_atol <abstol> - absolute tolerance of residual norm
909: . -snes_stol <stol> - convergence tolerance in terms of the norm of the change in the solution between steps
910: . -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
911: . -snes_max_it <max_it> - maximum number of iterations
912: . -snes_max_funcs <max_funcs> - maximum number of function evaluations
913: . -snes_force_iteration <force> - force `SNESSolve()` to take at least one iteration
914: . -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
915: . -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
916: . -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
917: . -snes_lag_preconditioner_persists <true,false> - retains the -snes_lag_preconditioner information across multiple SNESSolve()
918: . -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
919: . -snes_lag_jacobian_persists <true,false> - retains the -snes_lag_jacobian information across multiple SNESSolve()
920: . -snes_convergence_test <default,skip,correct_pressure> - convergence test in nonlinear solver. default `SNESConvergedDefault()`. skip `SNESConvergedSkip()` means continue iterating until max_it or some other criterion is reached, saving expense of convergence test. correct_pressure `SNESConvergedCorrectPressure()` has special handling of a pressure null space.
921: . -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
922: . -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
923: . -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
924: . -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
925: . -snes_monitor_lg_residualnorm - plots residual norm at each iteration
926: . -snes_monitor_lg_range - plots residual norm at each iteration
927: . -snes_monitor_pause_final - Pauses all monitor drawing after the solver ends
928: . -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
929: . -snes_fd_color - use finite differences with coloring to compute Jacobian
930: . -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each `KSP` iteration
931: . -snes_converged_reason - print the reason for convergence/divergence after each solve
932: . -npc_snes_type <type> - the `SNES` type to use as a nonlinear preconditioner
933: . -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.
934: - -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.
936: Options Database Keys for Eisenstat-Walker method:
937: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
938: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
939: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
940: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
941: . -snes_ksp_ew_gamma <gamma> - Sets gamma
942: . -snes_ksp_ew_alpha <alpha> - Sets alpha
943: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
944: - -snes_ksp_ew_threshold <threshold> - Sets threshold
946: Level: beginner
948: Notes:
949: To see all options, run your program with the -help option or consult the users manual
951: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
952: and computing explicitly with
953: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
955: .seealso: [](ch_snes), `SNESType`, `SNESSetOptionsPrefix()`, `SNESResetFromOptions()`, `SNES`, `SNESCreate()`, `MatCreateSNESMF()`, `MatFDColoring`
956: @*/
957: PetscErrorCode SNESSetFromOptions(SNES snes)
958: {
959: PetscBool flg, pcset, persist, set;
960: PetscInt i, indx, lag, grids, max_its, max_funcs;
961: const char *deft = SNESNEWTONLS;
962: const char *convtests[] = {"default", "skip", "correct_pressure"};
963: SNESKSPEW *kctx = NULL;
964: char type[256], monfilename[PETSC_MAX_PATH_LEN], ewprefix[256];
965: PCSide pcside;
966: const char *optionsprefix;
967: PetscReal rtol, abstol, stol;
969: PetscFunctionBegin;
971: PetscCall(SNESRegisterAll());
972: PetscObjectOptionsBegin((PetscObject)snes);
973: if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
974: PetscCall(PetscOptionsFList("-snes_type", "Nonlinear solver method", "SNESSetType", SNESList, deft, type, 256, &flg));
975: if (flg) {
976: PetscCall(SNESSetType(snes, type));
977: } else if (!((PetscObject)snes)->type_name) {
978: PetscCall(SNESSetType(snes, deft));
979: }
981: abstol = snes->abstol;
982: rtol = snes->rtol;
983: stol = snes->stol;
984: max_its = snes->max_its;
985: max_funcs = snes->max_funcs;
986: PetscCall(PetscOptionsReal("-snes_rtol", "Stop if decrease in function norm less than", "SNESSetTolerances", snes->rtol, &rtol, NULL));
987: PetscCall(PetscOptionsReal("-snes_atol", "Stop if function norm less than", "SNESSetTolerances", snes->abstol, &abstol, NULL));
988: PetscCall(PetscOptionsReal("-snes_stol", "Stop if step length less than", "SNESSetTolerances", snes->stol, &stol, NULL));
989: PetscCall(PetscOptionsInt("-snes_max_it", "Maximum iterations", "SNESSetTolerances", snes->max_its, &max_its, NULL));
990: PetscCall(PetscOptionsInt("-snes_max_funcs", "Maximum function evaluations", "SNESSetTolerances", snes->max_funcs, &max_funcs, NULL));
991: PetscCall(SNESSetTolerances(snes, abstol, rtol, stol, max_its, max_funcs));
993: PetscCall(PetscOptionsReal("-snes_divergence_tolerance", "Stop if residual norm increases by this factor", "SNESSetDivergenceTolerance", snes->divtol, &snes->divtol, &flg));
994: if (flg) PetscCall(SNESSetDivergenceTolerance(snes, snes->divtol));
996: PetscCall(PetscOptionsInt("-snes_max_fail", "Maximum nonlinear step failures", "SNESSetMaxNonlinearStepFailures", snes->maxFailures, &snes->maxFailures, &flg));
997: if (flg) PetscCall(SNESSetMaxNonlinearStepFailures(snes, snes->maxFailures));
999: PetscCall(PetscOptionsInt("-snes_max_linear_solve_fail", "Maximum failures in linear solves allowed", "SNESSetMaxLinearSolveFailures", snes->maxLinearSolveFailures, &snes->maxLinearSolveFailures, &flg));
1000: if (flg) PetscCall(SNESSetMaxLinearSolveFailures(snes, snes->maxLinearSolveFailures));
1002: PetscCall(PetscOptionsBool("-snes_error_if_not_converged", "Generate error if solver does not converge", "SNESSetErrorIfNotConverged", snes->errorifnotconverged, &snes->errorifnotconverged, NULL));
1003: PetscCall(PetscOptionsBool("-snes_force_iteration", "Force SNESSolve() to take at least one iteration", "SNESSetForceIteration", snes->forceiteration, &snes->forceiteration, NULL));
1004: PetscCall(PetscOptionsBool("-snes_check_jacobian_domain_error", "Check Jacobian domain error after Jacobian evaluation", "SNESCheckJacobianDomainError", snes->checkjacdomainerror, &snes->checkjacdomainerror, NULL));
1006: PetscCall(PetscOptionsInt("-snes_lag_preconditioner", "How often to rebuild preconditioner", "SNESSetLagPreconditioner", snes->lagpreconditioner, &lag, &flg));
1007: if (flg) {
1008: 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");
1009: PetscCall(SNESSetLagPreconditioner(snes, lag));
1010: }
1011: PetscCall(PetscOptionsBool("-snes_lag_preconditioner_persists", "Preconditioner lagging through multiple SNES solves", "SNESSetLagPreconditionerPersists", snes->lagjac_persist, &persist, &flg));
1012: if (flg) PetscCall(SNESSetLagPreconditionerPersists(snes, persist));
1013: PetscCall(PetscOptionsInt("-snes_lag_jacobian", "How often to rebuild Jacobian", "SNESSetLagJacobian", snes->lagjacobian, &lag, &flg));
1014: if (flg) {
1015: 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");
1016: PetscCall(SNESSetLagJacobian(snes, lag));
1017: }
1018: PetscCall(PetscOptionsBool("-snes_lag_jacobian_persists", "Jacobian lagging through multiple SNES solves", "SNESSetLagJacobianPersists", snes->lagjac_persist, &persist, &flg));
1019: if (flg) PetscCall(SNESSetLagJacobianPersists(snes, persist));
1021: PetscCall(PetscOptionsInt("-snes_grid_sequence", "Use grid sequencing to generate initial guess", "SNESSetGridSequence", snes->gridsequence, &grids, &flg));
1022: if (flg) PetscCall(SNESSetGridSequence(snes, grids));
1024: PetscCall(PetscOptionsEList("-snes_convergence_test", "Convergence test", "SNESSetConvergenceTest", convtests, PETSC_STATIC_ARRAY_LENGTH(convtests), "default", &indx, &flg));
1025: if (flg) {
1026: switch (indx) {
1027: case 0:
1028: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedDefault, NULL, NULL));
1029: break;
1030: case 1:
1031: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedSkip, NULL, NULL));
1032: break;
1033: case 2:
1034: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedCorrectPressure, NULL, NULL));
1035: break;
1036: }
1037: }
1039: PetscCall(PetscOptionsEList("-snes_norm_schedule", "SNES Norm schedule", "SNESSetNormSchedule", SNESNormSchedules, 5, "function", &indx, &flg));
1040: if (flg) PetscCall(SNESSetNormSchedule(snes, (SNESNormSchedule)indx));
1042: PetscCall(PetscOptionsEList("-snes_function_type", "SNES Norm schedule", "SNESSetFunctionType", SNESFunctionTypes, 2, "unpreconditioned", &indx, &flg));
1043: if (flg) PetscCall(SNESSetFunctionType(snes, (SNESFunctionType)indx));
1045: kctx = (SNESKSPEW *)snes->kspconvctx;
1047: PetscCall(PetscOptionsBool("-snes_ksp_ew", "Use Eisentat-Walker linear system convergence test", "SNESKSPSetUseEW", snes->ksp_ewconv, &snes->ksp_ewconv, NULL));
1049: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1050: PetscCall(PetscSNPrintf(ewprefix, sizeof(ewprefix), "%s%s", optionsprefix ? optionsprefix : "", "snes_"));
1051: PetscCall(SNESEWSetFromOptions_Private(kctx, PETSC_TRUE, PetscObjectComm((PetscObject)snes), ewprefix));
1053: flg = PETSC_FALSE;
1054: PetscCall(PetscOptionsBool("-snes_monitor_cancel", "Remove all monitors", "SNESMonitorCancel", flg, &flg, &set));
1055: if (set && flg) PetscCall(SNESMonitorCancel(snes));
1057: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor", "Monitor norm of function", "SNESMonitorDefault", SNESMonitorDefault, SNESMonitorDefaultSetUp));
1058: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_short", "Monitor norm of function with fewer digits", "SNESMonitorDefaultShort", SNESMonitorDefaultShort, NULL));
1059: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_range", "Monitor range of elements of function", "SNESMonitorRange", SNESMonitorRange, NULL));
1061: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_ratio", "Monitor ratios of the norm of function for consecutive steps", "SNESMonitorRatio", SNESMonitorRatio, SNESMonitorRatioSetUp));
1062: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_field", "Monitor norm of function (split into fields)", "SNESMonitorDefaultField", SNESMonitorDefaultField, NULL));
1063: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution", "View solution at each iteration", "SNESMonitorSolution", SNESMonitorSolution, NULL));
1064: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution_update", "View correction at each iteration", "SNESMonitorSolutionUpdate", SNESMonitorSolutionUpdate, NULL));
1065: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_residual", "View residual at each iteration", "SNESMonitorResidual", SNESMonitorResidual, NULL));
1066: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_jacupdate_spectrum", "Print the change in the spectrum of the Jacobian", "SNESMonitorJacUpdateSpectrum", SNESMonitorJacUpdateSpectrum, NULL));
1067: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_fields", "Monitor norm of function per field", "SNESMonitorSet", SNESMonitorFields, NULL));
1068: PetscCall(PetscOptionsBool("-snes_monitor_pause_final", "Pauses all draw monitors at the final iterate", "SNESMonitorPauseFinal_Internal", PETSC_FALSE, &snes->pauseFinal, NULL));
1070: PetscCall(PetscOptionsString("-snes_monitor_python", "Use Python function", "SNESMonitorSet", NULL, monfilename, sizeof(monfilename), &flg));
1071: if (flg) PetscCall(PetscPythonMonitorSet((PetscObject)snes, monfilename));
1073: flg = PETSC_FALSE;
1074: PetscCall(PetscOptionsBool("-snes_monitor_lg_range", "Plot function range at each iteration", "SNESMonitorLGRange", flg, &flg, NULL));
1075: if (flg) {
1076: PetscViewer ctx;
1078: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, NULL, PETSC_DECIDE, PETSC_DECIDE, 400, 300, &ctx));
1079: PetscCall(SNESMonitorSet(snes, SNESMonitorLGRange, ctx, (PetscCtxDestroyFn *)PetscViewerDestroy));
1080: }
1082: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
1083: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_converged_reason", &snes->convergedreasonviewer, &snes->convergedreasonformat, NULL));
1084: flg = PETSC_FALSE;
1085: PetscCall(PetscOptionsBool("-snes_converged_reason_view_cancel", "Remove all converged reason viewers", "SNESConvergedReasonViewCancel", flg, &flg, &set));
1086: if (set && flg) PetscCall(SNESConvergedReasonViewCancel(snes));
1088: flg = PETSC_FALSE;
1089: PetscCall(PetscOptionsBool("-snes_fd", "Use finite differences (slow) to compute Jacobian", "SNESComputeJacobianDefault", flg, &flg, NULL));
1090: if (flg) {
1091: void *functx;
1092: DM dm;
1093: PetscCall(SNESGetDM(snes, &dm));
1094: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1095: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
1096: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefault, functx));
1097: PetscCall(PetscInfo(snes, "Setting default finite difference Jacobian matrix\n"));
1098: }
1100: flg = PETSC_FALSE;
1101: PetscCall(PetscOptionsBool("-snes_fd_function", "Use finite differences (slow) to compute function from user objective", "SNESObjectiveComputeFunctionDefaultFD", flg, &flg, NULL));
1102: if (flg) PetscCall(SNESSetFunction(snes, NULL, SNESObjectiveComputeFunctionDefaultFD, NULL));
1104: flg = PETSC_FALSE;
1105: PetscCall(PetscOptionsBool("-snes_fd_color", "Use finite differences with coloring to compute Jacobian", "SNESComputeJacobianDefaultColor", flg, &flg, NULL));
1106: if (flg) {
1107: DM dm;
1108: PetscCall(SNESGetDM(snes, &dm));
1109: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1110: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefaultColor, NULL));
1111: PetscCall(PetscInfo(snes, "Setting default finite difference coloring Jacobian matrix\n"));
1112: }
1114: flg = PETSC_FALSE;
1115: PetscCall(PetscOptionsBool("-snes_mf_operator", "Use a Matrix-Free Jacobian with user-provided matrix for computing the preconditioner", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf_operator, &flg));
1116: if (flg && snes->mf_operator) {
1117: snes->mf_operator = PETSC_TRUE;
1118: snes->mf = PETSC_TRUE;
1119: }
1120: flg = PETSC_FALSE;
1121: PetscCall(PetscOptionsBool("-snes_mf", "Use a Matrix-Free Jacobian with no matrix for computing the preconditioner", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf, &flg));
1122: if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1123: PetscCall(PetscOptionsInt("-snes_mf_version", "Matrix-Free routines version 1 or 2", "None", snes->mf_version, &snes->mf_version, NULL));
1125: flg = PETSC_FALSE;
1126: PetscCall(SNESGetNPCSide(snes, &pcside));
1127: PetscCall(PetscOptionsEnum("-snes_npc_side", "SNES nonlinear preconditioner side", "SNESSetNPCSide", PCSides, (PetscEnum)pcside, (PetscEnum *)&pcside, &flg));
1128: if (flg) PetscCall(SNESSetNPCSide(snes, pcside));
1130: #if defined(PETSC_HAVE_SAWS)
1131: /*
1132: Publish convergence information using SAWs
1133: */
1134: flg = PETSC_FALSE;
1135: PetscCall(PetscOptionsBool("-snes_monitor_saws", "Publish SNES progress using SAWs", "SNESMonitorSet", flg, &flg, NULL));
1136: if (flg) {
1137: void *ctx;
1138: PetscCall(SNESMonitorSAWsCreate(snes, &ctx));
1139: PetscCall(SNESMonitorSet(snes, SNESMonitorSAWs, ctx, SNESMonitorSAWsDestroy));
1140: }
1141: #endif
1142: #if defined(PETSC_HAVE_SAWS)
1143: {
1144: PetscBool set;
1145: flg = PETSC_FALSE;
1146: PetscCall(PetscOptionsBool("-snes_saws_block", "Block for SAWs at end of SNESSolve", "PetscObjectSAWsBlock", ((PetscObject)snes)->amspublishblock, &flg, &set));
1147: if (set) PetscCall(PetscObjectSAWsSetBlock((PetscObject)snes, flg));
1148: }
1149: #endif
1151: for (i = 0; i < numberofsetfromoptions; i++) PetscCall((*othersetfromoptions[i])(snes));
1153: PetscTryTypeMethod(snes, setfromoptions, PetscOptionsObject);
1155: /* process any options handlers added with PetscObjectAddOptionsHandler() */
1156: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)snes, PetscOptionsObject));
1157: PetscOptionsEnd();
1159: if (snes->linesearch) {
1160: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
1161: PetscCall(SNESLineSearchSetFromOptions(snes->linesearch));
1162: }
1164: if (snes->usesksp) {
1165: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
1166: PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre));
1167: PetscCall(KSPSetFromOptions(snes->ksp));
1168: }
1170: /* if user has set the SNES NPC type via options database, create it. */
1171: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1172: PetscCall(PetscOptionsHasName(((PetscObject)snes)->options, optionsprefix, "-npc_snes_type", &pcset));
1173: if (pcset && (!snes->npc)) PetscCall(SNESGetNPC(snes, &snes->npc));
1174: if (snes->npc) PetscCall(SNESSetFromOptions(snes->npc));
1175: snes->setfromoptionscalled++;
1176: PetscFunctionReturn(PETSC_SUCCESS);
1177: }
1179: /*@
1180: SNESResetFromOptions - Sets various `SNES` and `KSP` parameters from user options ONLY if the `SNESSetFromOptions()` was previously called
1182: Collective
1184: Input Parameter:
1185: . snes - the `SNES` context
1187: Level: advanced
1189: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESSetOptionsPrefix()`
1190: @*/
1191: PetscErrorCode SNESResetFromOptions(SNES snes)
1192: {
1193: PetscFunctionBegin;
1194: if (snes->setfromoptionscalled) PetscCall(SNESSetFromOptions(snes));
1195: PetscFunctionReturn(PETSC_SUCCESS);
1196: }
1198: /*@C
1199: SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1200: the nonlinear solvers.
1202: Logically Collective; No Fortran Support
1204: Input Parameters:
1205: + snes - the `SNES` context
1206: . compute - function to compute the context
1207: - destroy - function to destroy the context, see `PetscCtxDestroyFn` for the calling sequence
1209: Calling sequence of `compute`:
1210: + snes - the `SNES` context
1211: - ctx - context to be computed
1213: Level: intermediate
1215: Note:
1216: This routine is useful if you are performing grid sequencing or using `SNESFAS` and need the appropriate context generated for each level.
1218: Use `SNESSetApplicationContext()` to see the context immediately
1220: .seealso: [](ch_snes), `SNESGetApplicationContext()`, `SNESSetApplicationContext()`, `PetscCtxDestroyFn`
1221: @*/
1222: PetscErrorCode SNESSetComputeApplicationContext(SNES snes, PetscErrorCode (*compute)(SNES snes, void **ctx), PetscCtxDestroyFn *destroy)
1223: {
1224: PetscFunctionBegin;
1226: snes->ops->usercompute = compute;
1227: snes->ops->ctxdestroy = destroy;
1228: PetscFunctionReturn(PETSC_SUCCESS);
1229: }
1231: /*@
1232: SNESSetApplicationContext - Sets the optional user-defined context for the nonlinear solvers.
1234: Logically Collective
1236: Input Parameters:
1237: + snes - the `SNES` context
1238: - ctx - the user context
1240: Level: intermediate
1242: Notes:
1243: Users can provide a context when constructing the `SNES` options and then access it inside their function, Jacobian computation, or other evaluation function
1244: with `SNESGetApplicationContext()`
1246: To provide a function that computes the context for you use `SNESSetComputeApplicationContext()`
1248: Fortran Note:
1249: This only works when `ctx` is a Fortran derived type (it cannot be a `PetscObject`), we recommend writing a Fortran interface definition for this
1250: function that tells the Fortran compiler the derived data type that is passed in as the `ctx` argument. See `SNESGetApplicationContext()` for
1251: an example.
1253: .seealso: [](ch_snes), `SNES`, `SNESSetComputeApplicationContext()`, `SNESGetApplicationContext()`
1254: @*/
1255: PetscErrorCode SNESSetApplicationContext(SNES snes, void *ctx)
1256: {
1257: KSP ksp;
1259: PetscFunctionBegin;
1261: PetscCall(SNESGetKSP(snes, &ksp));
1262: PetscCall(KSPSetApplicationContext(ksp, ctx));
1263: snes->ctx = ctx;
1264: PetscFunctionReturn(PETSC_SUCCESS);
1265: }
1267: /*@
1268: SNESGetApplicationContext - Gets the user-defined context for the
1269: nonlinear solvers set with `SNESGetApplicationContext()` or `SNESSetComputeApplicationContext()`
1271: Not Collective
1273: Input Parameter:
1274: . snes - `SNES` context
1276: Output Parameter:
1277: . ctx - user context
1279: Level: intermediate
1281: Fortran Notes:
1282: This only works when the context is a Fortran derived type (it cannot be a `PetscObject`) and you **must** write a Fortran interface definition for this
1283: function that tells the Fortran compiler the derived data type that is returned as the `ctx` argument. For example,
1284: .vb
1285: Interface SNESGetApplicationContext
1286: Subroutine SNESGetApplicationContext(snes,ctx,ierr)
1287: #include <petsc/finclude/petscsnes.h>
1288: use petscsnes
1289: SNES snes
1290: type(tUsertype), pointer :: ctx
1291: PetscErrorCode ierr
1292: End Subroutine
1293: End Interface SNESGetApplicationContext
1294: .ve
1296: The prototype for `ctx` must be
1297: .vb
1298: type(tUsertype), pointer :: ctx
1299: .ve
1301: .seealso: [](ch_snes), `SNESSetApplicationContext()`, `SNESSetComputeApplicationContext()`
1302: @*/
1303: PetscErrorCode SNESGetApplicationContext(SNES snes, PeCtx ctx)
1304: {
1305: PetscFunctionBegin;
1307: *(void **)ctx = snes->ctx;
1308: PetscFunctionReturn(PETSC_SUCCESS);
1309: }
1311: /*@
1312: SNESSetUseMatrixFree - indicates that `SNES` should use matrix-free finite difference matrix-vector products to apply the Jacobian.
1314: Logically Collective
1316: Input Parameters:
1317: + snes - `SNES` context
1318: . mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1319: - 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
1320: this option no matrix-element based preconditioners can be used in the linear solve since the matrix won't be explicitly available
1322: Options Database Keys:
1323: + -snes_mf_operator - use matrix-free only for the mat operator
1324: . -snes_mf - use matrix-free for both the mat and pmat operator
1325: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1326: - -snes_fd - compute the Jacobian via finite differences (slow)
1328: Level: intermediate
1330: Note:
1331: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
1332: and computing explicitly with
1333: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
1335: .seealso: [](ch_snes), `SNES`, `SNESGetUseMatrixFree()`, `MatCreateSNESMF()`, `SNESComputeJacobianDefaultColor()`, `MatFDColoring`
1336: @*/
1337: PetscErrorCode SNESSetUseMatrixFree(SNES snes, PetscBool mf_operator, PetscBool mf)
1338: {
1339: PetscFunctionBegin;
1343: snes->mf = mf_operator ? PETSC_TRUE : mf;
1344: snes->mf_operator = mf_operator;
1345: PetscFunctionReturn(PETSC_SUCCESS);
1346: }
1348: /*@
1349: SNESGetUseMatrixFree - indicates if the `SNES` uses matrix-free finite difference matrix vector products to apply the Jacobian.
1351: Not Collective, but the resulting flags will be the same on all MPI processes
1353: Input Parameter:
1354: . snes - `SNES` context
1356: Output Parameters:
1357: + mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1358: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored
1360: Level: intermediate
1362: .seealso: [](ch_snes), `SNES`, `SNESSetUseMatrixFree()`, `MatCreateSNESMF()`
1363: @*/
1364: PetscErrorCode SNESGetUseMatrixFree(SNES snes, PetscBool *mf_operator, PetscBool *mf)
1365: {
1366: PetscFunctionBegin;
1368: if (mf) *mf = snes->mf;
1369: if (mf_operator) *mf_operator = snes->mf_operator;
1370: PetscFunctionReturn(PETSC_SUCCESS);
1371: }
1373: /*@
1374: SNESGetIterationNumber - Gets the number of nonlinear iterations completed in the current or most recent `SNESSolve()`
1376: Not Collective
1378: Input Parameter:
1379: . snes - `SNES` context
1381: Output Parameter:
1382: . iter - iteration number
1384: Level: intermediate
1386: Notes:
1387: For example, during the computation of iteration 2 this would return 1.
1389: This is useful for using lagged Jacobians (where one does not recompute the
1390: Jacobian at each `SNES` iteration). For example, the code
1391: .vb
1392: ierr = SNESGetIterationNumber(snes,&it);
1393: if (!(it % 2)) {
1394: [compute Jacobian here]
1395: }
1396: .ve
1397: can be used in your function that computes the Jacobian to cause the Jacobian to be
1398: recomputed every second `SNES` iteration. See also `SNESSetLagJacobian()`
1400: After the `SNES` solve is complete this will return the number of nonlinear iterations used.
1402: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetLagJacobian()`, `SNESGetLinearSolveIterations()`, `SNESSetMonitor()`
1403: @*/
1404: PetscErrorCode SNESGetIterationNumber(SNES snes, PetscInt *iter)
1405: {
1406: PetscFunctionBegin;
1408: PetscAssertPointer(iter, 2);
1409: *iter = snes->iter;
1410: PetscFunctionReturn(PETSC_SUCCESS);
1411: }
1413: /*@
1414: SNESSetIterationNumber - Sets the current iteration number.
1416: Not Collective
1418: Input Parameters:
1419: + snes - `SNES` context
1420: - iter - iteration number
1422: Level: developer
1424: Note:
1425: This should only be called inside a `SNES` nonlinear solver.
1427: .seealso: [](ch_snes), `SNESGetLinearSolveIterations()`
1428: @*/
1429: PetscErrorCode SNESSetIterationNumber(SNES snes, PetscInt iter)
1430: {
1431: PetscFunctionBegin;
1433: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
1434: snes->iter = iter;
1435: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
1436: PetscFunctionReturn(PETSC_SUCCESS);
1437: }
1439: /*@
1440: SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1441: attempted by the nonlinear solver in the current or most recent `SNESSolve()` .
1443: Not Collective
1445: Input Parameter:
1446: . snes - `SNES` context
1448: Output Parameter:
1449: . nfails - number of unsuccessful steps attempted
1451: Level: intermediate
1453: Note:
1454: This counter is reset to zero for each successive call to `SNESSolve()`.
1456: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1457: `SNESSetMaxNonlinearStepFailures()`, `SNESGetMaxNonlinearStepFailures()`
1458: @*/
1459: PetscErrorCode SNESGetNonlinearStepFailures(SNES snes, PetscInt *nfails)
1460: {
1461: PetscFunctionBegin;
1463: PetscAssertPointer(nfails, 2);
1464: *nfails = snes->numFailures;
1465: PetscFunctionReturn(PETSC_SUCCESS);
1466: }
1468: /*@
1469: SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1470: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1472: Not Collective
1474: Input Parameters:
1475: + snes - `SNES` context
1476: - maxFails - maximum of unsuccessful steps allowed, use `PETSC_UNLIMITED` to have no limit on the number of failures
1478: Options Database Key:
1479: . -snes_max_fail <n> - maximum number of unsuccessful steps allowed
1481: Level: intermediate
1483: Developer Note:
1484: The options database key is wrong for this function name
1486: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1487: `SNESGetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1488: @*/
1489: PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1490: {
1491: PetscFunctionBegin;
1494: if (maxFails == PETSC_UNLIMITED) {
1495: snes->maxFailures = PETSC_INT_MAX;
1496: } else {
1497: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1498: snes->maxFailures = maxFails;
1499: }
1500: PetscFunctionReturn(PETSC_SUCCESS);
1501: }
1503: /*@
1504: SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1505: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1507: Not Collective
1509: Input Parameter:
1510: . snes - `SNES` context
1512: Output Parameter:
1513: . maxFails - maximum of unsuccessful steps
1515: Level: intermediate
1517: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1518: `SNESSetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1519: @*/
1520: PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1521: {
1522: PetscFunctionBegin;
1524: PetscAssertPointer(maxFails, 2);
1525: *maxFails = snes->maxFailures;
1526: PetscFunctionReturn(PETSC_SUCCESS);
1527: }
1529: /*@
1530: SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1531: done by the `SNES` object in the current or most recent `SNESSolve()`
1533: Not Collective
1535: Input Parameter:
1536: . snes - `SNES` context
1538: Output Parameter:
1539: . nfuncs - number of evaluations
1541: Level: intermediate
1543: Note:
1544: Reset every time `SNESSolve()` is called unless `SNESSetCountersReset()` is used.
1546: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`, `SNESSetCountersReset()`
1547: @*/
1548: PetscErrorCode SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1549: {
1550: PetscFunctionBegin;
1552: PetscAssertPointer(nfuncs, 2);
1553: *nfuncs = snes->nfuncs;
1554: PetscFunctionReturn(PETSC_SUCCESS);
1555: }
1557: /*@
1558: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1559: linear solvers in the current or most recent `SNESSolve()`
1561: Not Collective
1563: Input Parameter:
1564: . snes - `SNES` context
1566: Output Parameter:
1567: . nfails - number of failed solves
1569: Options Database Key:
1570: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1572: Level: intermediate
1574: Note:
1575: This counter is reset to zero for each successive call to `SNESSolve()`.
1577: .seealso: [](ch_snes), `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1578: @*/
1579: PetscErrorCode SNESGetLinearSolveFailures(SNES snes, PetscInt *nfails)
1580: {
1581: PetscFunctionBegin;
1583: PetscAssertPointer(nfails, 2);
1584: *nfails = snes->numLinearSolveFailures;
1585: PetscFunctionReturn(PETSC_SUCCESS);
1586: }
1588: /*@
1589: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1590: allowed before `SNES` returns with a diverged reason of `SNES_DIVERGED_LINEAR_SOLVE`
1592: Logically Collective
1594: Input Parameters:
1595: + snes - `SNES` context
1596: - maxFails - maximum allowed linear solve failures, use `PETSC_UNLIMITED` to have no limit on the number of failures
1598: Options Database Key:
1599: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1601: Level: intermediate
1603: Note:
1604: By default this is 0; that is `SNES` returns on the first failed linear solve
1606: Developer Note:
1607: The options database key is wrong for this function name
1609: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`
1610: @*/
1611: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1612: {
1613: PetscFunctionBegin;
1617: if (maxFails == PETSC_UNLIMITED) {
1618: snes->maxLinearSolveFailures = PETSC_INT_MAX;
1619: } else {
1620: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1621: snes->maxLinearSolveFailures = maxFails;
1622: }
1623: PetscFunctionReturn(PETSC_SUCCESS);
1624: }
1626: /*@
1627: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1628: are allowed before `SNES` returns as unsuccessful
1630: Not Collective
1632: Input Parameter:
1633: . snes - `SNES` context
1635: Output Parameter:
1636: . maxFails - maximum of unsuccessful solves allowed
1638: Level: intermediate
1640: Note:
1641: By default this is 1; that is `SNES` returns on the first failed linear solve
1643: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`,
1644: @*/
1645: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1646: {
1647: PetscFunctionBegin;
1649: PetscAssertPointer(maxFails, 2);
1650: *maxFails = snes->maxLinearSolveFailures;
1651: PetscFunctionReturn(PETSC_SUCCESS);
1652: }
1654: /*@
1655: SNESGetLinearSolveIterations - Gets the total number of linear iterations
1656: used by the nonlinear solver in the most recent `SNESSolve()`
1658: Not Collective
1660: Input Parameter:
1661: . snes - `SNES` context
1663: Output Parameter:
1664: . lits - number of linear iterations
1666: Level: intermediate
1668: Notes:
1669: This counter is reset to zero for each successive call to `SNESSolve()` unless `SNESSetCountersReset()` is used.
1671: 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
1672: then call `KSPGetIterationNumber()` after the failed solve.
1674: .seealso: [](ch_snes), `SNES`, `SNESGetIterationNumber()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESSetCountersReset()`
1675: @*/
1676: PetscErrorCode SNESGetLinearSolveIterations(SNES snes, PetscInt *lits)
1677: {
1678: PetscFunctionBegin;
1680: PetscAssertPointer(lits, 2);
1681: *lits = snes->linear_its;
1682: PetscFunctionReturn(PETSC_SUCCESS);
1683: }
1685: /*@
1686: SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1687: are reset every time `SNESSolve()` is called.
1689: Logically Collective
1691: Input Parameters:
1692: + snes - `SNES` context
1693: - reset - whether to reset the counters or not, defaults to `PETSC_TRUE`
1695: Level: developer
1697: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1698: @*/
1699: PetscErrorCode SNESSetCountersReset(SNES snes, PetscBool reset)
1700: {
1701: PetscFunctionBegin;
1704: snes->counters_reset = reset;
1705: PetscFunctionReturn(PETSC_SUCCESS);
1706: }
1708: /*@
1709: SNESResetCounters - Reset counters for linear iterations and function evaluations.
1711: Logically Collective
1713: Input Parameters:
1714: . snes - `SNES` context
1716: Level: developer
1718: Note:
1719: It honors the flag set with `SNESSetCountersReset()`
1721: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1722: @*/
1723: PetscErrorCode SNESResetCounters(SNES snes)
1724: {
1725: PetscFunctionBegin;
1727: if (snes->counters_reset) {
1728: snes->nfuncs = 0;
1729: snes->linear_its = 0;
1730: snes->numFailures = 0;
1731: }
1732: PetscFunctionReturn(PETSC_SUCCESS);
1733: }
1735: /*@
1736: SNESSetKSP - Sets a `KSP` context for the `SNES` object to use
1738: Not Collective, but the `SNES` and `KSP` objects must live on the same `MPI_Comm`
1740: Input Parameters:
1741: + snes - the `SNES` context
1742: - ksp - the `KSP` context
1744: Level: developer
1746: Notes:
1747: The `SNES` object already has its `KSP` object, you can obtain with `SNESGetKSP()`
1748: so this routine is rarely needed.
1750: The `KSP` object that is already in the `SNES` object has its reference count
1751: decreased by one when this is called.
1753: .seealso: [](ch_snes), `SNES`, `KSP`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`
1754: @*/
1755: PetscErrorCode SNESSetKSP(SNES snes, KSP ksp)
1756: {
1757: PetscFunctionBegin;
1760: PetscCheckSameComm(snes, 1, ksp, 2);
1761: PetscCall(PetscObjectReference((PetscObject)ksp));
1762: if (snes->ksp) PetscCall(PetscObjectDereference((PetscObject)snes->ksp));
1763: snes->ksp = ksp;
1764: PetscFunctionReturn(PETSC_SUCCESS);
1765: }
1767: /*@
1768: SNESParametersInitialize - Sets all the parameters in `snes` to their default value (when `SNESCreate()` was called) if they
1769: currently contain default values
1771: Collective
1773: Input Parameter:
1774: . snes - the `SNES` object
1776: Level: developer
1778: Developer Note:
1779: This is called by all the `SNESCreate_XXX()` routines.
1781: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`,
1782: `PetscObjectParameterSetDefault()`
1783: @*/
1784: PetscErrorCode SNESParametersInitialize(SNES snes)
1785: {
1786: PetscObjectParameterSetDefault(snes, max_its, 50);
1787: PetscObjectParameterSetDefault(snes, max_funcs, 10000);
1788: PetscObjectParameterSetDefault(snes, rtol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1789: PetscObjectParameterSetDefault(snes, abstol, PetscDefined(USE_REAL_SINGLE) ? 1.e-25 : 1.e-50);
1790: PetscObjectParameterSetDefault(snes, stol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1791: PetscObjectParameterSetDefault(snes, divtol, 1.e4);
1792: return PETSC_SUCCESS;
1793: }
1795: /*@
1796: SNESCreate - Creates a nonlinear solver context used to manage a set of nonlinear solves
1798: Collective
1800: Input Parameter:
1801: . comm - MPI communicator
1803: Output Parameter:
1804: . outsnes - the new `SNES` context
1806: Options Database Keys:
1807: + -snes_mf - Activates default matrix-free Jacobian-vector products, and no matrix to construct a preconditioner
1808: . -snes_mf_operator - Activates default matrix-free Jacobian-vector products, and a user-provided matrix as set by `SNESSetJacobian()`
1809: . -snes_fd_coloring - uses a relative fast computation of the Jacobian using finite differences and a graph coloring
1810: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
1812: Level: beginner
1814: Developer Notes:
1815: `SNES` always creates a `KSP` object even though many `SNES` methods do not use it. This is
1816: unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1817: particular method does use `KSP` and regulates if the information about the `KSP` is printed
1818: in `SNESView()`.
1820: `TSSetFromOptions()` does call `SNESSetFromOptions()` which can lead to users being confused
1821: by help messages about meaningless `SNES` options.
1823: `SNES` always creates the `snes->kspconvctx` even though it is used by only one type. This should be fixed.
1825: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
1826: @*/
1827: PetscErrorCode SNESCreate(MPI_Comm comm, SNES *outsnes)
1828: {
1829: SNES snes;
1830: SNESKSPEW *kctx;
1832: PetscFunctionBegin;
1833: PetscAssertPointer(outsnes, 2);
1834: PetscCall(SNESInitializePackage());
1836: PetscCall(PetscHeaderCreate(snes, SNES_CLASSID, "SNES", "Nonlinear solver", "SNES", comm, SNESDestroy, SNESView));
1837: snes->ops->converged = SNESConvergedDefault;
1838: snes->usesksp = PETSC_TRUE;
1839: snes->norm = 0.0;
1840: snes->xnorm = 0.0;
1841: snes->ynorm = 0.0;
1842: snes->normschedule = SNES_NORM_ALWAYS;
1843: snes->functype = SNES_FUNCTION_DEFAULT;
1844: snes->ttol = 0.0;
1846: snes->rnorm0 = 0;
1847: snes->nfuncs = 0;
1848: snes->numFailures = 0;
1849: snes->maxFailures = 1;
1850: snes->linear_its = 0;
1851: snes->lagjacobian = 1;
1852: snes->jac_iter = 0;
1853: snes->lagjac_persist = PETSC_FALSE;
1854: snes->lagpreconditioner = 1;
1855: snes->pre_iter = 0;
1856: snes->lagpre_persist = PETSC_FALSE;
1857: snes->numbermonitors = 0;
1858: snes->numberreasonviews = 0;
1859: snes->data = NULL;
1860: snes->setupcalled = PETSC_FALSE;
1861: snes->ksp_ewconv = PETSC_FALSE;
1862: snes->nwork = 0;
1863: snes->work = NULL;
1864: snes->nvwork = 0;
1865: snes->vwork = NULL;
1866: snes->conv_hist_len = 0;
1867: snes->conv_hist_max = 0;
1868: snes->conv_hist = NULL;
1869: snes->conv_hist_its = NULL;
1870: snes->conv_hist_reset = PETSC_TRUE;
1871: snes->counters_reset = PETSC_TRUE;
1872: snes->vec_func_init_set = PETSC_FALSE;
1873: snes->reason = SNES_CONVERGED_ITERATING;
1874: snes->npcside = PC_RIGHT;
1875: snes->setfromoptionscalled = 0;
1877: snes->mf = PETSC_FALSE;
1878: snes->mf_operator = PETSC_FALSE;
1879: snes->mf_version = 1;
1881: snes->numLinearSolveFailures = 0;
1882: snes->maxLinearSolveFailures = 1;
1884: snes->vizerotolerance = 1.e-8;
1885: snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;
1887: /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1888: snes->alwayscomputesfinalresidual = PETSC_FALSE;
1890: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1891: PetscCall(PetscNew(&kctx));
1893: snes->kspconvctx = kctx;
1894: kctx->version = 2;
1895: kctx->rtol_0 = 0.3; /* Eisenstat and Walker suggest rtol_0=.5, but
1896: this was too large for some test cases */
1897: kctx->rtol_last = 0.0;
1898: kctx->rtol_max = 0.9;
1899: kctx->gamma = 1.0;
1900: kctx->alpha = 0.5 * (1.0 + PetscSqrtReal(5.0));
1901: kctx->alpha2 = kctx->alpha;
1902: kctx->threshold = 0.1;
1903: kctx->lresid_last = 0.0;
1904: kctx->norm_last = 0.0;
1906: kctx->rk_last = 0.0;
1907: kctx->rk_last_2 = 0.0;
1908: kctx->rtol_last_2 = 0.0;
1909: kctx->v4_p1 = 0.1;
1910: kctx->v4_p2 = 0.4;
1911: kctx->v4_p3 = 0.7;
1912: kctx->v4_m1 = 0.8;
1913: kctx->v4_m2 = 0.5;
1914: kctx->v4_m3 = 0.1;
1915: kctx->v4_m4 = 0.5;
1917: PetscCall(SNESParametersInitialize(snes));
1918: *outsnes = snes;
1919: PetscFunctionReturn(PETSC_SUCCESS);
1920: }
1922: /*@C
1923: SNESSetFunction - Sets the function evaluation routine and function
1924: vector for use by the `SNES` routines in solving systems of nonlinear
1925: equations.
1927: Logically Collective
1929: Input Parameters:
1930: + snes - the `SNES` context
1931: . r - vector to store function values, may be `NULL`
1932: . f - function evaluation routine; for calling sequence see `SNESFunctionFn`
1933: - ctx - [optional] user-defined context for private data for the
1934: function evaluation routine (may be `NULL`)
1936: Level: beginner
1938: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetPicard()`, `SNESFunctionFn`
1939: @*/
1940: PetscErrorCode SNESSetFunction(SNES snes, Vec r, SNESFunctionFn *f, void *ctx)
1941: {
1942: DM dm;
1944: PetscFunctionBegin;
1946: if (r) {
1948: PetscCheckSameComm(snes, 1, r, 2);
1949: PetscCall(PetscObjectReference((PetscObject)r));
1950: PetscCall(VecDestroy(&snes->vec_func));
1951: snes->vec_func = r;
1952: }
1953: PetscCall(SNESGetDM(snes, &dm));
1954: PetscCall(DMSNESSetFunction(dm, f, ctx));
1955: if (f == SNESPicardComputeFunction) PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
1956: PetscFunctionReturn(PETSC_SUCCESS);
1957: }
1959: /*@C
1960: SNESSetInitialFunction - Set an already computed function evaluation at the initial guess to be reused by `SNESSolve()`.
1962: Logically Collective
1964: Input Parameters:
1965: + snes - the `SNES` context
1966: - f - vector to store function value
1968: Level: developer
1970: Notes:
1971: This should not be modified during the solution procedure.
1973: This is used extensively in the `SNESFAS` hierarchy and in nonlinear preconditioning.
1975: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetInitialFunctionNorm()`
1976: @*/
1977: PetscErrorCode SNESSetInitialFunction(SNES snes, Vec f)
1978: {
1979: Vec vec_func;
1981: PetscFunctionBegin;
1984: PetscCheckSameComm(snes, 1, f, 2);
1985: if (snes->npcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1986: snes->vec_func_init_set = PETSC_FALSE;
1987: PetscFunctionReturn(PETSC_SUCCESS);
1988: }
1989: PetscCall(SNESGetFunction(snes, &vec_func, NULL, NULL));
1990: PetscCall(VecCopy(f, vec_func));
1992: snes->vec_func_init_set = PETSC_TRUE;
1993: PetscFunctionReturn(PETSC_SUCCESS);
1994: }
1996: /*@
1997: SNESSetNormSchedule - Sets the `SNESNormSchedule` used in convergence and monitoring
1998: of the `SNES` method, when norms are computed in the solving process
2000: Logically Collective
2002: Input Parameters:
2003: + snes - the `SNES` context
2004: - normschedule - the frequency of norm computation
2006: Options Database Key:
2007: . -snes_norm_schedule <none, always, initialonly, finalonly, initialfinalonly> - set the schedule
2009: Level: advanced
2011: Notes:
2012: Only certain `SNES` methods support certain `SNESNormSchedules`. Most require evaluation
2013: of the nonlinear function and the taking of its norm at every iteration to
2014: even ensure convergence at all. However, methods such as custom Gauss-Seidel methods
2015: `SNESNGS` and the like do not require the norm of the function to be computed, and therefore
2016: may either be monitored for convergence or not. As these are often used as nonlinear
2017: preconditioners, monitoring the norm of their error is not a useful enterprise within
2018: their solution.
2020: .seealso: [](ch_snes), `SNESNormSchedule`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`
2021: @*/
2022: PetscErrorCode SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
2023: {
2024: PetscFunctionBegin;
2026: snes->normschedule = normschedule;
2027: PetscFunctionReturn(PETSC_SUCCESS);
2028: }
2030: /*@
2031: SNESGetNormSchedule - Gets the `SNESNormSchedule` used in convergence and monitoring
2032: of the `SNES` method.
2034: Logically Collective
2036: Input Parameters:
2037: + snes - the `SNES` context
2038: - normschedule - the type of the norm used
2040: Level: advanced
2042: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2043: @*/
2044: PetscErrorCode SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
2045: {
2046: PetscFunctionBegin;
2048: *normschedule = snes->normschedule;
2049: PetscFunctionReturn(PETSC_SUCCESS);
2050: }
2052: /*@
2053: SNESSetFunctionNorm - Sets the last computed residual norm.
2055: Logically Collective
2057: Input Parameters:
2058: + snes - the `SNES` context
2059: - norm - the value of the norm
2061: Level: developer
2063: .seealso: [](ch_snes), `SNES`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2064: @*/
2065: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
2066: {
2067: PetscFunctionBegin;
2069: snes->norm = norm;
2070: PetscFunctionReturn(PETSC_SUCCESS);
2071: }
2073: /*@
2074: SNESGetFunctionNorm - Gets the last computed norm of the residual
2076: Not Collective
2078: Input Parameter:
2079: . snes - the `SNES` context
2081: Output Parameter:
2082: . norm - the last computed residual norm
2084: Level: developer
2086: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2087: @*/
2088: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
2089: {
2090: PetscFunctionBegin;
2092: PetscAssertPointer(norm, 2);
2093: *norm = snes->norm;
2094: PetscFunctionReturn(PETSC_SUCCESS);
2095: }
2097: /*@
2098: SNESGetUpdateNorm - Gets the last computed norm of the solution update
2100: Not Collective
2102: Input Parameter:
2103: . snes - the `SNES` context
2105: Output Parameter:
2106: . ynorm - the last computed update norm
2108: Level: developer
2110: Note:
2111: The new solution is the current solution plus the update, so this norm is an indication of the size of the update
2113: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`
2114: @*/
2115: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2116: {
2117: PetscFunctionBegin;
2119: PetscAssertPointer(ynorm, 2);
2120: *ynorm = snes->ynorm;
2121: PetscFunctionReturn(PETSC_SUCCESS);
2122: }
2124: /*@
2125: SNESGetSolutionNorm - Gets the last computed norm of the solution
2127: Not Collective
2129: Input Parameter:
2130: . snes - the `SNES` context
2132: Output Parameter:
2133: . xnorm - the last computed solution norm
2135: Level: developer
2137: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`, `SNESGetUpdateNorm()`
2138: @*/
2139: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2140: {
2141: PetscFunctionBegin;
2143: PetscAssertPointer(xnorm, 2);
2144: *xnorm = snes->xnorm;
2145: PetscFunctionReturn(PETSC_SUCCESS);
2146: }
2148: /*@
2149: SNESSetFunctionType - Sets the `SNESFunctionType`
2150: of the `SNES` method.
2152: Logically Collective
2154: Input Parameters:
2155: + snes - the `SNES` context
2156: - type - the function type
2158: Level: developer
2160: Values of the function type\:
2161: + `SNES_FUNCTION_DEFAULT` - the default for the given `SNESType`
2162: . `SNES_FUNCTION_UNPRECONDITIONED` - an unpreconditioned function evaluation (this is the function provided with `SNESSetFunction()`
2163: - `SNES_FUNCTION_PRECONDITIONED` - a transformation of the function provided with `SNESSetFunction()`
2165: Note:
2166: Different `SNESType`s use this value in different ways
2168: .seealso: [](ch_snes), `SNES`, `SNESFunctionType`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2169: @*/
2170: PetscErrorCode SNESSetFunctionType(SNES snes, SNESFunctionType type)
2171: {
2172: PetscFunctionBegin;
2174: snes->functype = type;
2175: PetscFunctionReturn(PETSC_SUCCESS);
2176: }
2178: /*@
2179: SNESGetFunctionType - Gets the `SNESFunctionType` used in convergence and monitoring set with `SNESSetFunctionType()`
2180: of the SNES method.
2182: Logically Collective
2184: Input Parameters:
2185: + snes - the `SNES` context
2186: - type - the type of the function evaluation, see `SNESSetFunctionType()`
2188: Level: advanced
2190: .seealso: [](ch_snes), `SNESSetFunctionType()`, `SNESFunctionType`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2191: @*/
2192: PetscErrorCode SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2193: {
2194: PetscFunctionBegin;
2196: *type = snes->functype;
2197: PetscFunctionReturn(PETSC_SUCCESS);
2198: }
2200: /*@C
2201: SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2202: use with composed nonlinear solvers.
2204: Input Parameters:
2205: + snes - the `SNES` context, usually of the `SNESType` `SNESNGS`
2206: . f - function evaluation routine to apply Gauss-Seidel, see `SNESNGSFn` for calling sequence
2207: - ctx - [optional] user-defined context for private data for the smoother evaluation routine (may be `NULL`)
2209: Level: intermediate
2211: Note:
2212: The `SNESNGS` routines are used by the composed nonlinear solver to generate
2213: a problem appropriate update to the solution, particularly `SNESFAS`.
2215: .seealso: [](ch_snes), `SNESNGS`, `SNESGetNGS()`, `SNESNCG`, `SNESGetFunction()`, `SNESComputeNGS()`, `SNESNGSFn`
2216: @*/
2217: PetscErrorCode SNESSetNGS(SNES snes, SNESNGSFn *f, void *ctx)
2218: {
2219: DM dm;
2221: PetscFunctionBegin;
2223: PetscCall(SNESGetDM(snes, &dm));
2224: PetscCall(DMSNESSetNGS(dm, f, ctx));
2225: PetscFunctionReturn(PETSC_SUCCESS);
2226: }
2228: /*
2229: This is used for -snes_mf_operator; it uses a duplicate of snes->jacobian_pre because snes->jacobian_pre cannot be
2230: changed during the KSPSolve()
2231: */
2232: PetscErrorCode SNESPicardComputeMFFunction(SNES snes, Vec x, Vec f, void *ctx)
2233: {
2234: DM dm;
2235: DMSNES sdm;
2237: PetscFunctionBegin;
2238: PetscCall(SNESGetDM(snes, &dm));
2239: PetscCall(DMGetDMSNES(dm, &sdm));
2240: /* A(x)*x - b(x) */
2241: if (sdm->ops->computepfunction) {
2242: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2243: PetscCall(VecScale(f, -1.0));
2244: /* Cannot share nonzero pattern because of the possible use of SNESComputeJacobianDefault() */
2245: if (!snes->picard) PetscCall(MatDuplicate(snes->jacobian_pre, MAT_DO_NOT_COPY_VALUES, &snes->picard));
2246: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2247: PetscCall(MatMultAdd(snes->picard, x, f, f));
2248: } else {
2249: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2250: PetscCall(MatMult(snes->picard, x, f));
2251: }
2252: PetscFunctionReturn(PETSC_SUCCESS);
2253: }
2255: PetscErrorCode SNESPicardComputeFunction(SNES snes, Vec x, Vec f, void *ctx)
2256: {
2257: DM dm;
2258: DMSNES sdm;
2260: PetscFunctionBegin;
2261: PetscCall(SNESGetDM(snes, &dm));
2262: PetscCall(DMGetDMSNES(dm, &sdm));
2263: /* A(x)*x - b(x) */
2264: if (sdm->ops->computepfunction) {
2265: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2266: PetscCall(VecScale(f, -1.0));
2267: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2268: PetscCall(MatMultAdd(snes->jacobian_pre, x, f, f));
2269: } else {
2270: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2271: PetscCall(MatMult(snes->jacobian_pre, x, f));
2272: }
2273: PetscFunctionReturn(PETSC_SUCCESS);
2274: }
2276: PetscErrorCode SNESPicardComputeJacobian(SNES snes, Vec x1, Mat J, Mat B, void *ctx)
2277: {
2278: PetscFunctionBegin;
2279: /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2280: /* must assembly if matrix-free to get the last SNES solution */
2281: PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
2282: PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
2283: PetscFunctionReturn(PETSC_SUCCESS);
2284: }
2286: /*@C
2287: SNESSetPicard - Use `SNES` to solve the system $A(x) x = bp(x) + b $ via a Picard type iteration (Picard linearization)
2289: Logically Collective
2291: Input Parameters:
2292: + snes - the `SNES` context
2293: . r - vector to store function values, may be `NULL`
2294: . bp - function evaluation routine, may be `NULL`, for the calling sequence see `SNESFunctionFn`
2295: . Amat - matrix with which $A(x) x - bp(x) - b$ is to be computed
2296: . Pmat - matrix from which preconditioner is computed (usually the same as `Amat`)
2297: . J - function to compute matrix values, for the calling sequence see `SNESJacobianFn`
2298: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
2300: Level: intermediate
2302: Notes:
2303: It is often better to provide the nonlinear function $F()$ and some approximation to its Jacobian directly and use
2304: 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.
2306: One can call `SNESSetPicard()` or `SNESSetFunction()` (and possibly `SNESSetJacobian()`) but cannot call both
2308: Solves the equation $A(x) x = bp(x) - b$ via the defect correction algorithm $A(x^{n}) (x^{n+1} - x^{n}) = bp(x^{n}) + b - A(x^{n})x^{n}$.
2309: When an exact solver is used this corresponds to the "classic" Picard $A(x^{n}) x^{n+1} = bp(x^{n}) + b$ iteration.
2311: Run with `-snes_mf_operator` to solve the system with Newton's method using $A(x^{n})$ to construct the preconditioner.
2313: We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2314: the direct Picard iteration $A(x^n) x^{n+1} = bp(x^n) + b$
2316: 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
2317: 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
2318: different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument \:-).
2320: 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
2321: $A(x^{n})$ is used to build the preconditioner
2323: When used with `-snes_fd` this will compute the true Jacobian (very slowly one column at a time) and thus represent Newton's method.
2325: 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
2326: 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
2327: 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`.
2328: See the comment in src/snes/tutorials/ex15.c.
2330: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESGetPicard()`, `SNESLineSearchPreCheckPicard()`,
2331: `SNESFunctionFn`, `SNESJacobianFn`
2332: @*/
2333: PetscErrorCode SNESSetPicard(SNES snes, Vec r, SNESFunctionFn *bp, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
2334: {
2335: DM dm;
2337: PetscFunctionBegin;
2339: PetscCall(SNESGetDM(snes, &dm));
2340: PetscCall(DMSNESSetPicard(dm, bp, J, ctx));
2341: PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2342: PetscCall(SNESSetFunction(snes, r, SNESPicardComputeFunction, ctx));
2343: PetscCall(SNESSetJacobian(snes, Amat, Pmat, SNESPicardComputeJacobian, ctx));
2344: PetscFunctionReturn(PETSC_SUCCESS);
2345: }
2347: /*@C
2348: SNESGetPicard - Returns the context for the Picard iteration
2350: Not Collective, but `Vec` is parallel if `SNES` is parallel. Collective if `Vec` is requested, but has not been created yet.
2352: Input Parameter:
2353: . snes - the `SNES` context
2355: Output Parameters:
2356: + r - the function (or `NULL`)
2357: . f - the function (or `NULL`); for calling sequence see `SNESFunctionFn`
2358: . Amat - the matrix used to defined the operation A(x) x - b(x) (or `NULL`)
2359: . Pmat - the matrix from which the preconditioner will be constructed (or `NULL`)
2360: . J - the function for matrix evaluation (or `NULL`); for calling sequence see `SNESJacobianFn`
2361: - ctx - the function context (or `NULL`)
2363: Level: advanced
2365: .seealso: [](ch_snes), `SNESSetFunction()`, `SNESSetPicard()`, `SNESGetFunction()`, `SNESGetJacobian()`, `SNESGetDM()`, `SNESFunctionFn`, `SNESJacobianFn`
2366: @*/
2367: PetscErrorCode SNESGetPicard(SNES snes, Vec *r, SNESFunctionFn **f, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
2368: {
2369: DM dm;
2371: PetscFunctionBegin;
2373: PetscCall(SNESGetFunction(snes, r, NULL, NULL));
2374: PetscCall(SNESGetJacobian(snes, Amat, Pmat, NULL, NULL));
2375: PetscCall(SNESGetDM(snes, &dm));
2376: PetscCall(DMSNESGetPicard(dm, f, J, ctx));
2377: PetscFunctionReturn(PETSC_SUCCESS);
2378: }
2380: /*@C
2381: SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the nonlinear problem
2383: Logically Collective
2385: Input Parameters:
2386: + snes - the `SNES` context
2387: . func - function evaluation routine, see `SNESInitialGuessFn` for the calling sequence
2388: - ctx - [optional] user-defined context for private data for the
2389: function evaluation routine (may be `NULL`)
2391: Level: intermediate
2393: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESInitialGuessFn`
2394: @*/
2395: PetscErrorCode SNESSetComputeInitialGuess(SNES snes, SNESInitialGuessFn *func, void *ctx)
2396: {
2397: PetscFunctionBegin;
2399: if (func) snes->ops->computeinitialguess = func;
2400: if (ctx) snes->initialguessP = ctx;
2401: PetscFunctionReturn(PETSC_SUCCESS);
2402: }
2404: /*@C
2405: SNESGetRhs - Gets the vector for solving F(x) = `rhs`. If `rhs` is not set
2406: it assumes a zero right-hand side.
2408: Logically Collective
2410: Input Parameter:
2411: . snes - the `SNES` context
2413: Output Parameter:
2414: . rhs - the right-hand side vector or `NULL` if there is no right-hand side vector
2416: Level: intermediate
2418: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetFunction()`
2419: @*/
2420: PetscErrorCode SNESGetRhs(SNES snes, Vec *rhs)
2421: {
2422: PetscFunctionBegin;
2424: PetscAssertPointer(rhs, 2);
2425: *rhs = snes->vec_rhs;
2426: PetscFunctionReturn(PETSC_SUCCESS);
2427: }
2429: /*@
2430: SNESComputeFunction - Calls the function that has been set with `SNESSetFunction()`.
2432: Collective
2434: Input Parameters:
2435: + snes - the `SNES` context
2436: - x - input vector
2438: Output Parameter:
2439: . y - function vector, as set by `SNESSetFunction()`
2441: Level: developer
2443: Notes:
2444: `SNESComputeFunction()` is typically used within nonlinear solvers
2445: implementations, so users would not generally call this routine themselves.
2447: When solving for $F(x) = b$, this routine computes $y = F(x) - b$.
2449: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeMFFunction()`
2450: @*/
2451: PetscErrorCode SNESComputeFunction(SNES snes, Vec x, Vec y)
2452: {
2453: DM dm;
2454: DMSNES sdm;
2456: PetscFunctionBegin;
2460: PetscCheckSameComm(snes, 1, x, 2);
2461: PetscCheckSameComm(snes, 1, y, 3);
2462: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2464: PetscCall(SNESGetDM(snes, &dm));
2465: PetscCall(DMGetDMSNES(dm, &sdm));
2466: 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().");
2467: if (sdm->ops->computefunction) {
2468: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2469: PetscCall(VecLockReadPush(x));
2470: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2471: snes->domainerror = PETSC_FALSE;
2472: {
2473: void *ctx;
2474: SNESFunctionFn *computefunction;
2475: PetscCall(DMSNESGetFunction(dm, &computefunction, &ctx));
2476: PetscCallBack("SNES callback function", (*computefunction)(snes, x, y, ctx));
2477: }
2478: PetscCall(VecLockReadPop(x));
2479: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2480: } else /* if (snes->vec_rhs) */ {
2481: PetscCall(MatMult(snes->jacobian, x, y));
2482: }
2483: if (snes->vec_rhs) PetscCall(VecAXPY(y, -1.0, snes->vec_rhs));
2484: snes->nfuncs++;
2485: /*
2486: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2487: propagate the value to all processes
2488: */
2489: PetscCall(VecFlag(y, snes->domainerror));
2490: PetscFunctionReturn(PETSC_SUCCESS);
2491: }
2493: /*@
2494: SNESComputeMFFunction - Calls the function that has been set with `DMSNESSetMFFunction()`.
2496: Collective
2498: Input Parameters:
2499: + snes - the `SNES` context
2500: - x - input vector
2502: Output Parameter:
2503: . y - output vector
2505: Level: developer
2507: Notes:
2508: `SNESComputeMFFunction()` is used within the matrix-vector products called by the matrix created with `MatCreateSNESMF()`
2509: so users would not generally call this routine themselves.
2511: Since this function is intended for use with finite differencing it does not subtract the right-hand side vector provided with `SNESSolve()`
2512: while `SNESComputeFunction()` does. As such, this routine cannot be used with `MatMFFDSetBase()` with a provided F function value even if it applies the
2513: 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.
2515: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `MatCreateSNESMF()`, `DMSNESSetMFFunction()`
2516: @*/
2517: PetscErrorCode SNESComputeMFFunction(SNES snes, Vec x, Vec y)
2518: {
2519: DM dm;
2520: DMSNES sdm;
2522: PetscFunctionBegin;
2526: PetscCheckSameComm(snes, 1, x, 2);
2527: PetscCheckSameComm(snes, 1, y, 3);
2528: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2530: PetscCall(SNESGetDM(snes, &dm));
2531: PetscCall(DMGetDMSNES(dm, &sdm));
2532: PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2533: PetscCall(VecLockReadPush(x));
2534: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2535: snes->domainerror = PETSC_FALSE;
2536: PetscCallBack("SNES callback function", (*sdm->ops->computemffunction)(snes, x, y, sdm->mffunctionctx));
2537: PetscCall(VecLockReadPop(x));
2538: PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2539: snes->nfuncs++;
2540: /*
2541: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2542: propagate the value to all processes
2543: */
2544: PetscCall(VecFlag(y, snes->domainerror));
2545: PetscFunctionReturn(PETSC_SUCCESS);
2546: }
2548: /*@
2549: SNESComputeNGS - Calls the Gauss-Seidel function that has been set with `SNESSetNGS()`.
2551: Collective
2553: Input Parameters:
2554: + snes - the `SNES` context
2555: . x - input vector
2556: - b - rhs vector
2558: Output Parameter:
2559: . x - new solution vector
2561: Level: developer
2563: Note:
2564: `SNESComputeNGS()` is typically used within composed nonlinear solver
2565: implementations, so most users would not generally call this routine
2566: themselves.
2568: .seealso: [](ch_snes), `SNESNGSFn`, `SNESSetNGS()`, `SNESComputeFunction()`, `SNESNGS`
2569: @*/
2570: PetscErrorCode SNESComputeNGS(SNES snes, Vec b, Vec x)
2571: {
2572: DM dm;
2573: DMSNES sdm;
2575: PetscFunctionBegin;
2579: PetscCheckSameComm(snes, 1, x, 3);
2580: if (b) PetscCheckSameComm(snes, 1, b, 2);
2581: if (b) PetscCall(VecValidValues_Internal(b, 2, PETSC_TRUE));
2582: PetscCall(PetscLogEventBegin(SNES_NGSEval, snes, x, b, 0));
2583: PetscCall(SNESGetDM(snes, &dm));
2584: PetscCall(DMGetDMSNES(dm, &sdm));
2585: PetscCheck(sdm->ops->computegs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2586: if (b) PetscCall(VecLockReadPush(b));
2587: PetscCallBack("SNES callback NGS", (*sdm->ops->computegs)(snes, x, b, sdm->gsctx));
2588: if (b) PetscCall(VecLockReadPop(b));
2589: PetscCall(PetscLogEventEnd(SNES_NGSEval, snes, x, b, 0));
2590: PetscFunctionReturn(PETSC_SUCCESS);
2591: }
2593: static PetscErrorCode SNESComputeFunction_FD(SNES snes, Vec Xin, Vec G)
2594: {
2595: Vec X;
2596: PetscScalar *g;
2597: PetscReal f, f2;
2598: PetscInt low, high, N, i;
2599: PetscBool flg;
2600: PetscReal h = .5 * PETSC_SQRT_MACHINE_EPSILON;
2602: PetscFunctionBegin;
2603: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_fd_delta", &h, &flg));
2604: PetscCall(VecDuplicate(Xin, &X));
2605: PetscCall(VecCopy(Xin, X));
2606: PetscCall(VecGetSize(X, &N));
2607: PetscCall(VecGetOwnershipRange(X, &low, &high));
2608: PetscCall(VecSetOption(X, VEC_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE));
2609: PetscCall(VecGetArray(G, &g));
2610: for (i = 0; i < N; i++) {
2611: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2612: PetscCall(VecAssemblyBegin(X));
2613: PetscCall(VecAssemblyEnd(X));
2614: PetscCall(SNESComputeObjective(snes, X, &f));
2615: PetscCall(VecSetValue(X, i, 2.0 * h, ADD_VALUES));
2616: PetscCall(VecAssemblyBegin(X));
2617: PetscCall(VecAssemblyEnd(X));
2618: PetscCall(SNESComputeObjective(snes, X, &f2));
2619: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2620: PetscCall(VecAssemblyBegin(X));
2621: PetscCall(VecAssemblyEnd(X));
2622: if (i >= low && i < high) g[i - low] = (f2 - f) / (2.0 * h);
2623: }
2624: PetscCall(VecRestoreArray(G, &g));
2625: PetscCall(VecDestroy(&X));
2626: PetscFunctionReturn(PETSC_SUCCESS);
2627: }
2629: PetscErrorCode SNESTestFunction(SNES snes)
2630: {
2631: Vec x, g1, g2, g3;
2632: PetscBool complete_print = PETSC_FALSE, test = PETSC_FALSE;
2633: PetscReal hcnorm, fdnorm, hcmax, fdmax, diffmax, diffnorm;
2634: PetscScalar dot;
2635: MPI_Comm comm;
2636: PetscViewer viewer, mviewer;
2637: PetscViewerFormat format;
2638: PetscInt tabs;
2639: static PetscBool directionsprinted = PETSC_FALSE;
2640: SNESObjectiveFn *objective;
2642: PetscFunctionBegin;
2643: PetscCall(SNESGetObjective(snes, &objective, NULL));
2644: if (!objective) PetscFunctionReturn(PETSC_SUCCESS);
2646: PetscObjectOptionsBegin((PetscObject)snes);
2647: PetscCall(PetscOptionsName("-snes_test_function", "Compare hand-coded and finite difference function", "None", &test));
2648: PetscCall(PetscOptionsViewer("-snes_test_function_view", "View difference between hand-coded and finite difference function element entries", "None", &mviewer, &format, &complete_print));
2649: PetscOptionsEnd();
2650: if (!test) {
2651: if (complete_print) PetscCall(PetscViewerDestroy(&mviewer));
2652: PetscFunctionReturn(PETSC_SUCCESS);
2653: }
2655: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2656: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2657: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2658: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2659: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Function -------------\n"));
2660: if (!complete_print && !directionsprinted) {
2661: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_function_view and optionally -snes_test_function <threshold> to show difference\n"));
2662: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference function entries greater than <threshold>.\n"));
2663: }
2664: if (!directionsprinted) {
2665: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Function, if (for double precision runs) ||F - Ffd||/||F|| is\n"));
2666: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Function is probably correct.\n"));
2667: directionsprinted = PETSC_TRUE;
2668: }
2669: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2671: PetscCall(SNESGetSolution(snes, &x));
2672: PetscCall(VecDuplicate(x, &g1));
2673: PetscCall(VecDuplicate(x, &g2));
2674: PetscCall(VecDuplicate(x, &g3));
2675: PetscCall(SNESComputeFunction(snes, x, g1));
2676: PetscCall(SNESComputeFunction_FD(snes, x, g2));
2678: PetscCall(VecNorm(g2, NORM_2, &fdnorm));
2679: PetscCall(VecNorm(g1, NORM_2, &hcnorm));
2680: PetscCall(VecNorm(g2, NORM_INFINITY, &fdmax));
2681: PetscCall(VecNorm(g1, NORM_INFINITY, &hcmax));
2682: PetscCall(VecDot(g1, g2, &dot));
2683: PetscCall(VecCopy(g1, g3));
2684: PetscCall(VecAXPY(g3, -1.0, g2));
2685: PetscCall(VecNorm(g3, NORM_2, &diffnorm));
2686: PetscCall(VecNorm(g3, NORM_INFINITY, &diffmax));
2687: PetscCall(PetscViewerASCIIPrintf(viewer, " ||Ffd|| %g, ||F|| = %g, angle cosine = (Ffd'F)/||Ffd||||F|| = %g\n", (double)fdnorm, (double)hcnorm, (double)(PetscRealPart(dot) / (fdnorm * hcnorm))));
2688: PetscCall(PetscViewerASCIIPrintf(viewer, " 2-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffnorm / PetscMax(hcnorm, fdnorm)), (double)diffnorm));
2689: PetscCall(PetscViewerASCIIPrintf(viewer, " max-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffmax / PetscMax(hcmax, fdmax)), (double)diffmax));
2691: if (complete_print) {
2692: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded function ----------\n"));
2693: PetscCall(VecView(g1, mviewer));
2694: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference function ----------\n"));
2695: PetscCall(VecView(g2, mviewer));
2696: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference function ----------\n"));
2697: PetscCall(VecView(g3, mviewer));
2698: }
2699: PetscCall(VecDestroy(&g1));
2700: PetscCall(VecDestroy(&g2));
2701: PetscCall(VecDestroy(&g3));
2703: if (complete_print) {
2704: PetscCall(PetscViewerPopFormat(mviewer));
2705: PetscCall(PetscViewerDestroy(&mviewer));
2706: }
2707: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2708: PetscFunctionReturn(PETSC_SUCCESS);
2709: }
2711: PetscErrorCode SNESTestJacobian(SNES snes)
2712: {
2713: Mat A, B, C, D, jacobian;
2714: Vec x = snes->vec_sol, f;
2715: PetscReal nrm, gnorm;
2716: PetscReal threshold = 1.e-5;
2717: MatType mattype;
2718: PetscInt m, n, M, N;
2719: void *functx;
2720: PetscBool complete_print = PETSC_FALSE, threshold_print = PETSC_FALSE, test = PETSC_FALSE, flg, istranspose;
2721: PetscViewer viewer, mviewer;
2722: MPI_Comm comm;
2723: PetscInt tabs;
2724: static PetscBool directionsprinted = PETSC_FALSE;
2725: PetscViewerFormat format;
2727: PetscFunctionBegin;
2728: PetscObjectOptionsBegin((PetscObject)snes);
2729: PetscCall(PetscOptionsName("-snes_test_jacobian", "Compare hand-coded and finite difference Jacobians", "None", &test));
2730: PetscCall(PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold, NULL));
2731: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display", "-snes_test_jacobian_view", "3.13", NULL));
2732: PetscCall(PetscOptionsViewer("-snes_test_jacobian_view", "View difference between hand-coded and finite difference Jacobians element entries", "None", &mviewer, &format, &complete_print));
2733: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display_threshold", "-snes_test_jacobian", "3.13", "-snes_test_jacobian accepts an optional threshold (since v3.10)"));
2734: 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));
2735: PetscOptionsEnd();
2736: if (!test) PetscFunctionReturn(PETSC_SUCCESS);
2738: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2739: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2740: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2741: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2742: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian -------------\n"));
2743: if (!complete_print && !directionsprinted) {
2744: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n"));
2745: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference Jacobian entries greater than <threshold>.\n"));
2746: }
2747: if (!directionsprinted) {
2748: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n"));
2749: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Jacobian is probably correct.\n"));
2750: directionsprinted = PETSC_TRUE;
2751: }
2752: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2754: PetscCall(PetscObjectTypeCompare((PetscObject)snes->jacobian, MATMFFD, &flg));
2755: if (!flg) jacobian = snes->jacobian;
2756: else jacobian = snes->jacobian_pre;
2758: if (!x) PetscCall(MatCreateVecs(jacobian, &x, NULL));
2759: else PetscCall(PetscObjectReference((PetscObject)x));
2760: PetscCall(VecDuplicate(x, &f));
2762: /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2763: PetscCall(SNESComputeFunction(snes, x, f));
2764: PetscCall(VecDestroy(&f));
2765: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESKSPTRANSPOSEONLY, &istranspose));
2766: while (jacobian) {
2767: Mat JT = NULL, Jsave = NULL;
2769: if (istranspose) {
2770: PetscCall(MatCreateTranspose(jacobian, &JT));
2771: Jsave = jacobian;
2772: jacobian = JT;
2773: }
2774: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)jacobian, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
2775: if (flg) {
2776: A = jacobian;
2777: PetscCall(PetscObjectReference((PetscObject)A));
2778: } else {
2779: PetscCall(MatComputeOperator(jacobian, MATAIJ, &A));
2780: }
2782: PetscCall(MatGetType(A, &mattype));
2783: PetscCall(MatGetSize(A, &M, &N));
2784: PetscCall(MatGetLocalSize(A, &m, &n));
2785: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &B));
2786: PetscCall(MatSetType(B, mattype));
2787: PetscCall(MatSetSizes(B, m, n, M, N));
2788: PetscCall(MatSetBlockSizesFromMats(B, A, A));
2789: PetscCall(MatSetUp(B));
2790: PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2792: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
2793: PetscCall(SNESComputeJacobianDefault(snes, x, B, B, functx));
2795: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &D));
2796: PetscCall(MatAYPX(D, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2797: PetscCall(MatNorm(D, NORM_FROBENIUS, &nrm));
2798: PetscCall(MatNorm(A, NORM_FROBENIUS, &gnorm));
2799: PetscCall(MatDestroy(&D));
2800: if (!gnorm) gnorm = 1; /* just in case */
2801: PetscCall(PetscViewerASCIIPrintf(viewer, " ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n", (double)(nrm / gnorm), (double)nrm));
2803: if (complete_print) {
2804: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded Jacobian ----------\n"));
2805: PetscCall(MatView(A, mviewer));
2806: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference Jacobian ----------\n"));
2807: PetscCall(MatView(B, mviewer));
2808: }
2810: if (threshold_print || complete_print) {
2811: PetscInt Istart, Iend, *ccols, bncols, cncols, j, row;
2812: PetscScalar *cvals;
2813: const PetscInt *bcols;
2814: const PetscScalar *bvals;
2816: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2817: PetscCall(MatSetType(C, mattype));
2818: PetscCall(MatSetSizes(C, m, n, M, N));
2819: PetscCall(MatSetBlockSizesFromMats(C, A, A));
2820: PetscCall(MatSetUp(C));
2821: PetscCall(MatSetOption(C, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2823: PetscCall(MatAYPX(B, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2824: PetscCall(MatGetOwnershipRange(B, &Istart, &Iend));
2826: for (row = Istart; row < Iend; row++) {
2827: PetscCall(MatGetRow(B, row, &bncols, &bcols, &bvals));
2828: PetscCall(PetscMalloc2(bncols, &ccols, bncols, &cvals));
2829: for (j = 0, cncols = 0; j < bncols; j++) {
2830: if (PetscAbsScalar(bvals[j]) > threshold) {
2831: ccols[cncols] = bcols[j];
2832: cvals[cncols] = bvals[j];
2833: cncols += 1;
2834: }
2835: }
2836: if (cncols) PetscCall(MatSetValues(C, 1, &row, cncols, ccols, cvals, INSERT_VALUES));
2837: PetscCall(MatRestoreRow(B, row, &bncols, &bcols, &bvals));
2838: PetscCall(PetscFree2(ccols, cvals));
2839: }
2840: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2841: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2842: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n", (double)threshold));
2843: PetscCall(MatView(C, complete_print ? mviewer : viewer));
2844: PetscCall(MatDestroy(&C));
2845: }
2846: PetscCall(MatDestroy(&A));
2847: PetscCall(MatDestroy(&B));
2848: PetscCall(MatDestroy(&JT));
2849: if (Jsave) jacobian = Jsave;
2850: if (jacobian != snes->jacobian_pre) {
2851: jacobian = snes->jacobian_pre;
2852: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian for preconditioner -------------\n"));
2853: } else jacobian = NULL;
2854: }
2855: PetscCall(VecDestroy(&x));
2856: if (complete_print) PetscCall(PetscViewerPopFormat(mviewer));
2857: if (mviewer) PetscCall(PetscViewerDestroy(&mviewer));
2858: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2859: PetscFunctionReturn(PETSC_SUCCESS);
2860: }
2862: /*@
2863: SNESComputeJacobian - Computes the Jacobian matrix that has been set with `SNESSetJacobian()`.
2865: Collective
2867: Input Parameters:
2868: + snes - the `SNES` context
2869: - X - input vector
2871: Output Parameters:
2872: + A - Jacobian matrix
2873: - B - optional matrix for building the preconditioner, usually the same as `A`
2875: Options Database Keys:
2876: + -snes_lag_preconditioner <lag> - how often to rebuild preconditioner
2877: . -snes_lag_jacobian <lag> - how often to rebuild Jacobian
2878: . -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.
2879: . -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
2880: . -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2881: . -snes_compare_explicit_draw - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2882: . -snes_compare_explicit_contour - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2883: . -snes_compare_operator - Make the comparison options above use the operator instead of the matrix used to construct the preconditioner
2884: . -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2885: . -snes_compare_coloring_display - Compute the finite difference Jacobian using coloring and display verbose differences
2886: . -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2887: . -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2888: . -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2889: . -snes_compare_coloring_draw - Compute the finite difference Jacobian using coloring and draw differences
2890: - -snes_compare_coloring_draw_contour - Compute the finite difference Jacobian using coloring and show contours of matrices and differences
2892: Level: developer
2894: Note:
2895: Most users should not need to explicitly call this routine, as it
2896: is used internally within the nonlinear solvers.
2898: Developer Note:
2899: 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
2900: with the `SNESType` of test that has been removed.
2902: .seealso: [](ch_snes), `SNESSetJacobian()`, `KSPSetOperators()`, `MatStructure`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
2903: @*/
2904: PetscErrorCode SNESComputeJacobian(SNES snes, Vec X, Mat A, Mat B)
2905: {
2906: PetscBool flag;
2907: DM dm;
2908: DMSNES sdm;
2909: KSP ksp;
2911: PetscFunctionBegin;
2914: PetscCheckSameComm(snes, 1, X, 2);
2915: PetscCall(VecValidValues_Internal(X, 2, PETSC_TRUE));
2916: PetscCall(SNESGetDM(snes, &dm));
2917: PetscCall(DMGetDMSNES(dm, &sdm));
2919: /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix-free */
2920: if (snes->lagjacobian == -2) {
2921: snes->lagjacobian = -1;
2923: PetscCall(PetscInfo(snes, "Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n"));
2924: } else if (snes->lagjacobian == -1) {
2925: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is -1\n"));
2926: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2927: if (flag) {
2928: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2929: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2930: }
2931: PetscFunctionReturn(PETSC_SUCCESS);
2932: } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2933: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagjacobian, snes->iter));
2934: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2935: if (flag) {
2936: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2937: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2938: }
2939: PetscFunctionReturn(PETSC_SUCCESS);
2940: }
2941: if (snes->npc && snes->npcside == PC_LEFT) {
2942: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2943: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2944: PetscFunctionReturn(PETSC_SUCCESS);
2945: }
2947: PetscCall(PetscLogEventBegin(SNES_JacobianEval, snes, X, A, B));
2948: PetscCall(VecLockReadPush(X));
2949: {
2950: void *ctx;
2951: SNESJacobianFn *J;
2952: PetscCall(DMSNESGetJacobian(dm, &J, &ctx));
2953: PetscCallBack("SNES callback Jacobian", (*J)(snes, X, A, B, ctx));
2954: }
2955: PetscCall(VecLockReadPop(X));
2956: PetscCall(PetscLogEventEnd(SNES_JacobianEval, snes, X, A, B));
2958: /* attach latest linearization point to the matrix used to construct the preconditioner */
2959: PetscCall(PetscObjectCompose((PetscObject)B, "__SNES_latest_X", (PetscObject)X));
2961: /* the next line ensures that snes->ksp exists */
2962: PetscCall(SNESGetKSP(snes, &ksp));
2963: if (snes->lagpreconditioner == -2) {
2964: PetscCall(PetscInfo(snes, "Rebuilding preconditioner exactly once since lag is -2\n"));
2965: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2966: snes->lagpreconditioner = -1;
2967: } else if (snes->lagpreconditioner == -1) {
2968: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is -1\n"));
2969: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2970: } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2971: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagpreconditioner, snes->iter));
2972: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2973: } else {
2974: PetscCall(PetscInfo(snes, "Rebuilding preconditioner\n"));
2975: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2976: }
2978: /* monkey business to allow testing Jacobians in multilevel solvers.
2979: This is needed because the SNESTestXXX interface does not accept vectors and matrices */
2980: {
2981: Vec xsave = snes->vec_sol;
2982: Mat jacobiansave = snes->jacobian;
2983: Mat jacobian_presave = snes->jacobian_pre;
2985: snes->vec_sol = X;
2986: snes->jacobian = A;
2987: snes->jacobian_pre = B;
2988: PetscCall(SNESTestFunction(snes));
2989: PetscCall(SNESTestJacobian(snes));
2991: snes->vec_sol = xsave;
2992: snes->jacobian = jacobiansave;
2993: snes->jacobian_pre = jacobian_presave;
2994: }
2996: {
2997: PetscBool flag = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_operator = PETSC_FALSE;
2998: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit", NULL, NULL, &flag));
2999: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw", NULL, NULL, &flag_draw));
3000: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw_contour", NULL, NULL, &flag_contour));
3001: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_operator", NULL, NULL, &flag_operator));
3002: if (flag || flag_draw || flag_contour) {
3003: Mat Bexp_mine = NULL, Bexp, FDexp;
3004: PetscViewer vdraw, vstdout;
3005: PetscBool flg;
3006: if (flag_operator) {
3007: PetscCall(MatComputeOperator(A, MATAIJ, &Bexp_mine));
3008: Bexp = Bexp_mine;
3009: } else {
3010: /* See if the matrix used to construct the preconditioner can be viewed and added directly */
3011: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)B, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPIBAIJ, ""));
3012: if (flg) Bexp = B;
3013: else {
3014: /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
3015: PetscCall(MatComputeOperator(B, MATAIJ, &Bexp_mine));
3016: Bexp = Bexp_mine;
3017: }
3018: }
3019: PetscCall(MatConvert(Bexp, MATSAME, MAT_INITIAL_MATRIX, &FDexp));
3020: PetscCall(SNESComputeJacobianDefault(snes, X, FDexp, FDexp, NULL));
3021: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3022: if (flag_draw || flag_contour) {
3023: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Explicit Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3024: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3025: } else vdraw = NULL;
3026: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit %s\n", flag_operator ? "Jacobian" : "preconditioning Jacobian"));
3027: if (flag) PetscCall(MatView(Bexp, vstdout));
3028: if (vdraw) PetscCall(MatView(Bexp, vdraw));
3029: PetscCall(PetscViewerASCIIPrintf(vstdout, "Finite difference Jacobian\n"));
3030: if (flag) PetscCall(MatView(FDexp, vstdout));
3031: if (vdraw) PetscCall(MatView(FDexp, vdraw));
3032: PetscCall(MatAYPX(FDexp, -1.0, Bexp, SAME_NONZERO_PATTERN));
3033: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian\n"));
3034: if (flag) PetscCall(MatView(FDexp, vstdout));
3035: if (vdraw) { /* Always use contour for the difference */
3036: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3037: PetscCall(MatView(FDexp, vdraw));
3038: PetscCall(PetscViewerPopFormat(vdraw));
3039: }
3040: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3041: PetscCall(PetscViewerDestroy(&vdraw));
3042: PetscCall(MatDestroy(&Bexp_mine));
3043: PetscCall(MatDestroy(&FDexp));
3044: }
3045: }
3046: {
3047: PetscBool flag = PETSC_FALSE, flag_display = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_threshold = PETSC_FALSE;
3048: PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON, threshold_rtol = 10 * PETSC_SQRT_MACHINE_EPSILON;
3049: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring", NULL, NULL, &flag));
3050: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_display", NULL, NULL, &flag_display));
3051: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw", NULL, NULL, &flag_draw));
3052: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw_contour", NULL, NULL, &flag_contour));
3053: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold", NULL, NULL, &flag_threshold));
3054: if (flag_threshold) {
3055: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_rtol", &threshold_rtol, NULL));
3056: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_atol", &threshold_atol, NULL));
3057: }
3058: if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
3059: Mat Bfd;
3060: PetscViewer vdraw, vstdout;
3061: MatColoring coloring;
3062: ISColoring iscoloring;
3063: MatFDColoring matfdcoloring;
3064: SNESFunctionFn *func;
3065: void *funcctx;
3066: PetscReal norm1, norm2, normmax;
3068: PetscCall(MatDuplicate(B, MAT_DO_NOT_COPY_VALUES, &Bfd));
3069: PetscCall(MatColoringCreate(Bfd, &coloring));
3070: PetscCall(MatColoringSetType(coloring, MATCOLORINGSL));
3071: PetscCall(MatColoringSetFromOptions(coloring));
3072: PetscCall(MatColoringApply(coloring, &iscoloring));
3073: PetscCall(MatColoringDestroy(&coloring));
3074: PetscCall(MatFDColoringCreate(Bfd, iscoloring, &matfdcoloring));
3075: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3076: PetscCall(MatFDColoringSetUp(Bfd, iscoloring, matfdcoloring));
3077: PetscCall(ISColoringDestroy(&iscoloring));
3079: /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
3080: PetscCall(SNESGetFunction(snes, NULL, &func, &funcctx));
3081: PetscCall(MatFDColoringSetFunction(matfdcoloring, (PetscErrorCode (*)(void))func, funcctx));
3082: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring, ((PetscObject)snes)->prefix));
3083: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring, "coloring_"));
3084: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3085: PetscCall(MatFDColoringApply(Bfd, matfdcoloring, X, snes));
3086: PetscCall(MatFDColoringDestroy(&matfdcoloring));
3088: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3089: if (flag_draw || flag_contour) {
3090: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Colored Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3091: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3092: } else vdraw = NULL;
3093: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit preconditioning Jacobian\n"));
3094: if (flag_display) PetscCall(MatView(B, vstdout));
3095: if (vdraw) PetscCall(MatView(B, vdraw));
3096: PetscCall(PetscViewerASCIIPrintf(vstdout, "Colored Finite difference Jacobian\n"));
3097: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3098: if (vdraw) PetscCall(MatView(Bfd, vdraw));
3099: PetscCall(MatAYPX(Bfd, -1.0, B, SAME_NONZERO_PATTERN));
3100: PetscCall(MatNorm(Bfd, NORM_1, &norm1));
3101: PetscCall(MatNorm(Bfd, NORM_FROBENIUS, &norm2));
3102: PetscCall(MatNorm(Bfd, NORM_MAX, &normmax));
3103: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n", (double)norm1, (double)norm2, (double)normmax));
3104: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3105: if (vdraw) { /* Always use contour for the difference */
3106: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3107: PetscCall(MatView(Bfd, vdraw));
3108: PetscCall(PetscViewerPopFormat(vdraw));
3109: }
3110: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3112: if (flag_threshold) {
3113: PetscInt bs, rstart, rend, i;
3114: PetscCall(MatGetBlockSize(B, &bs));
3115: PetscCall(MatGetOwnershipRange(B, &rstart, &rend));
3116: for (i = rstart; i < rend; i++) {
3117: const PetscScalar *ba, *ca;
3118: const PetscInt *bj, *cj;
3119: PetscInt bn, cn, j, maxentrycol = -1, maxdiffcol = -1, maxrdiffcol = -1;
3120: PetscReal maxentry = 0, maxdiff = 0, maxrdiff = 0;
3121: PetscCall(MatGetRow(B, i, &bn, &bj, &ba));
3122: PetscCall(MatGetRow(Bfd, i, &cn, &cj, &ca));
3123: PetscCheck(bn == cn, ((PetscObject)A)->comm, PETSC_ERR_PLIB, "Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
3124: for (j = 0; j < bn; j++) {
3125: PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3126: if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
3127: maxentrycol = bj[j];
3128: maxentry = PetscRealPart(ba[j]);
3129: }
3130: if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
3131: maxdiffcol = bj[j];
3132: maxdiff = PetscRealPart(ca[j]);
3133: }
3134: if (rdiff > maxrdiff) {
3135: maxrdiffcol = bj[j];
3136: maxrdiff = rdiff;
3137: }
3138: }
3139: if (maxrdiff > 1) {
3140: 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));
3141: for (j = 0; j < bn; j++) {
3142: PetscReal rdiff;
3143: rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3144: if (rdiff > 1) PetscCall(PetscViewerASCIIPrintf(vstdout, " (%" PetscInt_FMT ",%g:%g)", bj[j], (double)PetscRealPart(ba[j]), (double)PetscRealPart(ca[j])));
3145: }
3146: PetscCall(PetscViewerASCIIPrintf(vstdout, "\n"));
3147: }
3148: PetscCall(MatRestoreRow(B, i, &bn, &bj, &ba));
3149: PetscCall(MatRestoreRow(Bfd, i, &cn, &cj, &ca));
3150: }
3151: }
3152: PetscCall(PetscViewerDestroy(&vdraw));
3153: PetscCall(MatDestroy(&Bfd));
3154: }
3155: }
3156: PetscFunctionReturn(PETSC_SUCCESS);
3157: }
3159: /*@C
3160: SNESSetJacobian - Sets the function to compute Jacobian as well as the
3161: location to store the matrix.
3163: Logically Collective
3165: Input Parameters:
3166: + snes - the `SNES` context
3167: . Amat - the matrix that defines the (approximate) Jacobian
3168: . Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
3169: . J - Jacobian evaluation routine (if `NULL` then `SNES` retains any previously set value), see `SNESJacobianFn` for details
3170: - ctx - [optional] user-defined context for private data for the
3171: Jacobian evaluation routine (may be `NULL`) (if `NULL` then `SNES` retains any previously set value)
3173: Level: beginner
3175: Notes:
3176: If the `Amat` matrix and `Pmat` matrix are different you must call `MatAssemblyBegin()`/`MatAssemblyEnd()` on
3177: each matrix.
3179: If you know the operator `Amat` has a null space you can use `MatSetNullSpace()` and `MatSetTransposeNullSpace()` to supply the null
3180: space to `Amat` and the `KSP` solvers will automatically use that null space as needed during the solution process.
3182: If using `SNESComputeJacobianDefaultColor()` to assemble a Jacobian, the `ctx` argument
3183: must be a `MatFDColoring`.
3185: Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian. One common
3186: example is to use the "Picard linearization" which only differentiates through the highest order parts of each term using `SNESSetPicard()`
3188: .seealso: [](ch_snes), `SNES`, `KSPSetOperators()`, `SNESSetFunction()`, `MatMFFDComputeJacobian()`, `SNESComputeJacobianDefaultColor()`, `MatStructure`,
3189: `SNESSetPicard()`, `SNESJacobianFn`, `SNESFunctionFn`
3190: @*/
3191: PetscErrorCode SNESSetJacobian(SNES snes, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
3192: {
3193: DM dm;
3195: PetscFunctionBegin;
3199: if (Amat) PetscCheckSameComm(snes, 1, Amat, 2);
3200: if (Pmat) PetscCheckSameComm(snes, 1, Pmat, 3);
3201: PetscCall(SNESGetDM(snes, &dm));
3202: PetscCall(DMSNESSetJacobian(dm, J, ctx));
3203: if (Amat) {
3204: PetscCall(PetscObjectReference((PetscObject)Amat));
3205: PetscCall(MatDestroy(&snes->jacobian));
3207: snes->jacobian = Amat;
3208: }
3209: if (Pmat) {
3210: PetscCall(PetscObjectReference((PetscObject)Pmat));
3211: PetscCall(MatDestroy(&snes->jacobian_pre));
3213: snes->jacobian_pre = Pmat;
3214: }
3215: PetscFunctionReturn(PETSC_SUCCESS);
3216: }
3218: /*@C
3219: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
3220: provided context for evaluating the Jacobian.
3222: Not Collective, but `Mat` object will be parallel if `SNES` is
3224: Input Parameter:
3225: . snes - the nonlinear solver context
3227: Output Parameters:
3228: + Amat - location to stash (approximate) Jacobian matrix (or `NULL`)
3229: . Pmat - location to stash matrix used to compute the preconditioner (or `NULL`)
3230: . J - location to put Jacobian function (or `NULL`), for calling sequence see `SNESJacobianFn`
3231: - ctx - location to stash Jacobian ctx (or `NULL`)
3233: Level: advanced
3235: .seealso: [](ch_snes), `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFn`, `SNESGetFunction()`
3236: @*/
3237: PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
3238: {
3239: DM dm;
3241: PetscFunctionBegin;
3243: if (Amat) *Amat = snes->jacobian;
3244: if (Pmat) *Pmat = snes->jacobian_pre;
3245: PetscCall(SNESGetDM(snes, &dm));
3246: PetscCall(DMSNESGetJacobian(dm, J, ctx));
3247: PetscFunctionReturn(PETSC_SUCCESS);
3248: }
3250: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3251: {
3252: DM dm;
3253: DMSNES sdm;
3255: PetscFunctionBegin;
3256: PetscCall(SNESGetDM(snes, &dm));
3257: PetscCall(DMGetDMSNES(dm, &sdm));
3258: if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3259: DM dm;
3260: PetscBool isdense, ismf;
3262: PetscCall(SNESGetDM(snes, &dm));
3263: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &isdense, MATSEQDENSE, MATMPIDENSE, MATDENSE, NULL));
3264: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &ismf, MATMFFD, MATSHELL, NULL));
3265: if (isdense) {
3266: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefault, NULL));
3267: } else if (!ismf) {
3268: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefaultColor, NULL));
3269: }
3270: }
3271: PetscFunctionReturn(PETSC_SUCCESS);
3272: }
3274: /*@
3275: SNESSetUp - Sets up the internal data structures for the later use
3276: of a nonlinear solver `SNESSolve()`.
3278: Collective
3280: Input Parameter:
3281: . snes - the `SNES` context
3283: Level: advanced
3285: Note:
3286: For basic use of the `SNES` solvers the user does not need to explicitly call
3287: `SNESSetUp()`, since these actions will automatically occur during
3288: the call to `SNESSolve()`. However, if one wishes to control this
3289: phase separately, `SNESSetUp()` should be called after `SNESCreate()`
3290: and optional routines of the form SNESSetXXX(), but before `SNESSolve()`.
3292: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`, `SNESDestroy()`, `SNESSetFromOptions()`
3293: @*/
3294: PetscErrorCode SNESSetUp(SNES snes)
3295: {
3296: DM dm;
3297: DMSNES sdm;
3298: SNESLineSearch linesearch, pclinesearch;
3299: void *lsprectx, *lspostctx;
3300: PetscBool mf_operator, mf;
3301: Vec f, fpc;
3302: void *funcctx;
3303: void *jacctx, *appctx;
3304: Mat j, jpre;
3305: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, void *);
3306: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *);
3307: SNESFunctionFn *func;
3308: SNESJacobianFn *jac;
3310: PetscFunctionBegin;
3312: if (snes->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
3313: PetscCall(PetscLogEventBegin(SNES_SetUp, snes, 0, 0, 0));
3315: if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, SNESNEWTONLS));
3317: PetscCall(SNESGetFunction(snes, &snes->vec_func, NULL, NULL));
3319: PetscCall(SNESGetDM(snes, &dm));
3320: PetscCall(DMGetDMSNES(dm, &sdm));
3321: PetscCall(SNESSetDefaultComputeJacobian(snes));
3323: if (!snes->vec_func) PetscCall(DMCreateGlobalVector(dm, &snes->vec_func));
3325: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
3327: if (snes->linesearch) {
3328: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
3329: PetscCall(SNESLineSearchSetFunction(snes->linesearch, SNESComputeFunction));
3330: }
3332: PetscCall(SNESGetUseMatrixFree(snes, &mf_operator, &mf));
3333: if (snes->npc && snes->npcside == PC_LEFT) {
3334: snes->mf = PETSC_TRUE;
3335: snes->mf_operator = PETSC_FALSE;
3336: }
3338: if (snes->npc) {
3339: /* copy the DM over */
3340: PetscCall(SNESGetDM(snes, &dm));
3341: PetscCall(SNESSetDM(snes->npc, dm));
3343: PetscCall(SNESGetFunction(snes, &f, &func, &funcctx));
3344: PetscCall(VecDuplicate(f, &fpc));
3345: PetscCall(SNESSetFunction(snes->npc, fpc, func, funcctx));
3346: PetscCall(SNESGetJacobian(snes, &j, &jpre, &jac, &jacctx));
3347: PetscCall(SNESSetJacobian(snes->npc, j, jpre, jac, jacctx));
3348: PetscCall(SNESGetApplicationContext(snes, &appctx));
3349: PetscCall(SNESSetApplicationContext(snes->npc, appctx));
3350: PetscCall(SNESSetUseMatrixFree(snes->npc, mf_operator, mf));
3351: PetscCall(VecDestroy(&fpc));
3353: /* copy the function pointers over */
3354: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)snes->npc));
3356: /* default to 1 iteration */
3357: PetscCall(SNESSetTolerances(snes->npc, 0.0, 0.0, 0.0, 1, snes->npc->max_funcs));
3358: if (snes->npcside == PC_RIGHT) {
3359: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_FINAL_ONLY));
3360: } else {
3361: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_NONE));
3362: }
3363: PetscCall(SNESSetFromOptions(snes->npc));
3365: /* copy the line search context over */
3366: if (snes->linesearch && snes->npc->linesearch) {
3367: PetscCall(SNESGetLineSearch(snes, &linesearch));
3368: PetscCall(SNESGetLineSearch(snes->npc, &pclinesearch));
3369: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
3370: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
3371: PetscCall(SNESLineSearchSetPreCheck(pclinesearch, precheck, lsprectx));
3372: PetscCall(SNESLineSearchSetPostCheck(pclinesearch, postcheck, lspostctx));
3373: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch));
3374: }
3375: }
3376: if (snes->mf) PetscCall(SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version));
3377: if (snes->ops->usercompute && !snes->ctx) PetscCallBack("SNES callback compute application context", (*snes->ops->usercompute)(snes, &snes->ctx));
3379: snes->jac_iter = 0;
3380: snes->pre_iter = 0;
3382: PetscTryTypeMethod(snes, setup);
3384: PetscCall(SNESSetDefaultComputeJacobian(snes));
3386: if (snes->npc && snes->npcside == PC_LEFT) {
3387: if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3388: if (snes->linesearch) {
3389: PetscCall(SNESGetLineSearch(snes, &linesearch));
3390: PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunctionDefaultNPC));
3391: }
3392: }
3393: }
3394: PetscCall(PetscLogEventEnd(SNES_SetUp, snes, 0, 0, 0));
3395: snes->setupcalled = PETSC_TRUE;
3396: PetscFunctionReturn(PETSC_SUCCESS);
3397: }
3399: /*@
3400: SNESReset - Resets a `SNES` context to the state it was in before `SNESSetUp()` was called and removes any allocated `Vec` and `Mat` from its data structures
3402: Collective
3404: Input Parameter:
3405: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3407: Level: intermediate
3409: Notes:
3410: Any options set on the `SNES` object, including those set with `SNESSetFromOptions()` remain.
3412: Call this if you wish to reuse a `SNES` but with different size vectors
3414: Also calls the application context destroy routine set with `SNESSetComputeApplicationContext()`
3416: .seealso: [](ch_snes), `SNES`, `SNESDestroy()`, `SNESCreate()`, `SNESSetUp()`, `SNESSolve()`
3417: @*/
3418: PetscErrorCode SNESReset(SNES snes)
3419: {
3420: PetscFunctionBegin;
3422: if (snes->ops->ctxdestroy && snes->ctx) {
3423: PetscCallBack("SNES callback destroy application context", (*snes->ops->ctxdestroy)(&snes->ctx));
3424: snes->ctx = NULL;
3425: }
3426: if (snes->npc) PetscCall(SNESReset(snes->npc));
3428: PetscTryTypeMethod(snes, reset);
3429: if (snes->ksp) PetscCall(KSPReset(snes->ksp));
3431: if (snes->linesearch) PetscCall(SNESLineSearchReset(snes->linesearch));
3433: PetscCall(VecDestroy(&snes->vec_rhs));
3434: PetscCall(VecDestroy(&snes->vec_sol));
3435: PetscCall(VecDestroy(&snes->vec_sol_update));
3436: PetscCall(VecDestroy(&snes->vec_func));
3437: PetscCall(MatDestroy(&snes->jacobian));
3438: PetscCall(MatDestroy(&snes->jacobian_pre));
3439: PetscCall(MatDestroy(&snes->picard));
3440: PetscCall(VecDestroyVecs(snes->nwork, &snes->work));
3441: PetscCall(VecDestroyVecs(snes->nvwork, &snes->vwork));
3443: snes->alwayscomputesfinalresidual = PETSC_FALSE;
3445: snes->nwork = snes->nvwork = 0;
3446: snes->setupcalled = PETSC_FALSE;
3447: PetscFunctionReturn(PETSC_SUCCESS);
3448: }
3450: /*@
3451: SNESConvergedReasonViewCancel - Clears all the reason view functions for a `SNES` object provided with `SNESConvergedReasonViewSet()` also
3452: removes the default viewer.
3454: Collective
3456: Input Parameter:
3457: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3459: Level: intermediate
3461: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESReset()`, `SNESConvergedReasonViewSet()`
3462: @*/
3463: PetscErrorCode SNESConvergedReasonViewCancel(SNES snes)
3464: {
3465: PetscInt i;
3467: PetscFunctionBegin;
3469: for (i = 0; i < snes->numberreasonviews; i++) {
3470: if (snes->reasonviewdestroy[i]) PetscCall((*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]));
3471: }
3472: snes->numberreasonviews = 0;
3473: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
3474: PetscFunctionReturn(PETSC_SUCCESS);
3475: }
3477: /*@
3478: SNESDestroy - Destroys the nonlinear solver context that was created
3479: with `SNESCreate()`.
3481: Collective
3483: Input Parameter:
3484: . snes - the `SNES` context
3486: Level: beginner
3488: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`
3489: @*/
3490: PetscErrorCode SNESDestroy(SNES *snes)
3491: {
3492: DM dm;
3494: PetscFunctionBegin;
3495: if (!*snes) PetscFunctionReturn(PETSC_SUCCESS);
3497: if (--((PetscObject)*snes)->refct > 0) {
3498: *snes = NULL;
3499: PetscFunctionReturn(PETSC_SUCCESS);
3500: }
3502: PetscCall(SNESReset(*snes));
3503: PetscCall(SNESDestroy(&(*snes)->npc));
3505: /* if memory was published with SAWs then destroy it */
3506: PetscCall(PetscObjectSAWsViewOff((PetscObject)*snes));
3507: PetscTryTypeMethod(*snes, destroy);
3509: dm = (*snes)->dm;
3510: while (dm) {
3511: PetscCall(DMCoarsenHookRemove(dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, *snes));
3512: PetscCall(DMGetCoarseDM(dm, &dm));
3513: }
3515: PetscCall(DMDestroy(&(*snes)->dm));
3516: PetscCall(KSPDestroy(&(*snes)->ksp));
3517: PetscCall(SNESLineSearchDestroy(&(*snes)->linesearch));
3519: PetscCall(PetscFree((*snes)->kspconvctx));
3520: if ((*snes)->ops->convergeddestroy) PetscCall((*(*snes)->ops->convergeddestroy)((*snes)->cnvP));
3521: if ((*snes)->conv_hist_alloc) PetscCall(PetscFree2((*snes)->conv_hist, (*snes)->conv_hist_its));
3522: PetscCall(SNESMonitorCancel(*snes));
3523: PetscCall(SNESConvergedReasonViewCancel(*snes));
3524: PetscCall(PetscHeaderDestroy(snes));
3525: PetscFunctionReturn(PETSC_SUCCESS);
3526: }
3528: /* ----------- Routines to set solver parameters ---------- */
3530: /*@
3531: SNESSetLagPreconditioner - Sets when the preconditioner is rebuilt in the nonlinear solve `SNESSolve()`.
3533: Logically Collective
3535: Input Parameters:
3536: + snes - the `SNES` context
3537: - lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3538: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3540: Options Database Keys:
3541: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3542: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3543: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3544: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3546: Level: intermediate
3548: Notes:
3549: The default is 1
3551: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagPreconditionerPersists()` was called
3553: `SNESSetLagPreconditionerPersists()` allows using the same uniform lagging (for example every second linear solve) across multiple nonlinear solves.
3555: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetLagPreconditionerPersists()`,
3556: `SNESSetLagJacobianPersists()`, `SNES`, `SNESSolve()`
3557: @*/
3558: PetscErrorCode SNESSetLagPreconditioner(SNES snes, PetscInt lag)
3559: {
3560: PetscFunctionBegin;
3562: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3563: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3565: snes->lagpreconditioner = lag;
3566: PetscFunctionReturn(PETSC_SUCCESS);
3567: }
3569: /*@
3570: SNESSetGridSequence - sets the number of steps of grid sequencing that `SNES` will do
3572: Logically Collective
3574: Input Parameters:
3575: + snes - the `SNES` context
3576: - steps - the number of refinements to do, defaults to 0
3578: Options Database Key:
3579: . -snes_grid_sequence <steps> - Use grid sequencing to generate initial guess
3581: Level: intermediate
3583: Notes:
3584: Once grid sequencing is turned on `SNESSolve()` will automatically perform the solve on each grid refinement.
3586: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3588: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetGridSequence()`,
3589: `SNESSetDM()`, `SNESSolve()`
3590: @*/
3591: PetscErrorCode SNESSetGridSequence(SNES snes, PetscInt steps)
3592: {
3593: PetscFunctionBegin;
3596: snes->gridsequence = steps;
3597: PetscFunctionReturn(PETSC_SUCCESS);
3598: }
3600: /*@
3601: SNESGetGridSequence - gets the number of steps of grid sequencing that `SNES` will do
3603: Logically Collective
3605: Input Parameter:
3606: . snes - the `SNES` context
3608: Output Parameter:
3609: . steps - the number of refinements to do, defaults to 0
3611: Level: intermediate
3613: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetGridSequence()`
3614: @*/
3615: PetscErrorCode SNESGetGridSequence(SNES snes, PetscInt *steps)
3616: {
3617: PetscFunctionBegin;
3619: *steps = snes->gridsequence;
3620: PetscFunctionReturn(PETSC_SUCCESS);
3621: }
3623: /*@
3624: SNESGetLagPreconditioner - Return how often the preconditioner is rebuilt
3626: Not Collective
3628: Input Parameter:
3629: . snes - the `SNES` context
3631: Output Parameter:
3632: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3633: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3635: Level: intermediate
3637: Notes:
3638: The default is 1
3640: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3642: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3643: @*/
3644: PetscErrorCode SNESGetLagPreconditioner(SNES snes, PetscInt *lag)
3645: {
3646: PetscFunctionBegin;
3648: *lag = snes->lagpreconditioner;
3649: PetscFunctionReturn(PETSC_SUCCESS);
3650: }
3652: /*@
3653: SNESSetLagJacobian - Set when the Jacobian is rebuilt in the nonlinear solve. See `SNESSetLagPreconditioner()` for determining how
3654: often the preconditioner is rebuilt.
3656: Logically Collective
3658: Input Parameters:
3659: + snes - the `SNES` context
3660: - lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3661: the Jacobian is built etc. -2 means rebuild at next chance but then never again
3663: Options Database Keys:
3664: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3665: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3666: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3667: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag.
3669: Level: intermediate
3671: Notes:
3672: The default is 1
3674: The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3676: 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
3677: at the next Newton step but never again (unless it is reset to another value)
3679: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagPreconditioner()`, `SNESGetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3680: @*/
3681: PetscErrorCode SNESSetLagJacobian(SNES snes, PetscInt lag)
3682: {
3683: PetscFunctionBegin;
3685: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3686: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3688: snes->lagjacobian = lag;
3689: PetscFunctionReturn(PETSC_SUCCESS);
3690: }
3692: /*@
3693: SNESGetLagJacobian - Get how often the Jacobian is rebuilt. See `SNESGetLagPreconditioner()` to determine when the preconditioner is rebuilt
3695: Not Collective
3697: Input Parameter:
3698: . snes - the `SNES` context
3700: Output Parameter:
3701: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3702: the Jacobian is built etc.
3704: Level: intermediate
3706: Notes:
3707: The default is 1
3709: The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagJacobianPersists()` was called.
3711: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobian()`, `SNESSetLagPreconditioner()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3713: @*/
3714: PetscErrorCode SNESGetLagJacobian(SNES snes, PetscInt *lag)
3715: {
3716: PetscFunctionBegin;
3718: *lag = snes->lagjacobian;
3719: PetscFunctionReturn(PETSC_SUCCESS);
3720: }
3722: /*@
3723: SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple nonlinear solves
3725: Logically collective
3727: Input Parameters:
3728: + snes - the `SNES` context
3729: - flg - jacobian lagging persists if true
3731: Options Database Keys:
3732: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3733: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3734: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3735: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3737: Level: advanced
3739: Notes:
3740: Normally when `SNESSetLagJacobian()` is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3742: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3743: several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3744: timesteps may present huge efficiency gains.
3746: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditionerPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`
3747: @*/
3748: PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
3749: {
3750: PetscFunctionBegin;
3753: snes->lagjac_persist = flg;
3754: PetscFunctionReturn(PETSC_SUCCESS);
3755: }
3757: /*@
3758: SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves
3760: Logically Collective
3762: Input Parameters:
3763: + snes - the `SNES` context
3764: - flg - preconditioner lagging persists if true
3766: Options Database Keys:
3767: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3768: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3769: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3770: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3772: Level: developer
3774: Notes:
3775: Normally when `SNESSetLagPreconditioner()` is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3777: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3778: by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3779: several timesteps may present huge efficiency gains.
3781: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobianPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagPreconditioner()`
3782: @*/
3783: PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)
3784: {
3785: PetscFunctionBegin;
3788: snes->lagpre_persist = flg;
3789: PetscFunctionReturn(PETSC_SUCCESS);
3790: }
3792: /*@
3793: SNESSetForceIteration - force `SNESSolve()` to take at least one iteration regardless of the initial residual norm
3795: Logically Collective
3797: Input Parameters:
3798: + snes - the `SNES` context
3799: - force - `PETSC_TRUE` require at least one iteration
3801: Options Database Key:
3802: . -snes_force_iteration <force> - Sets forcing an iteration
3804: Level: intermediate
3806: Note:
3807: This is used sometimes with `TS` to prevent `TS` from detecting a false steady state solution
3809: .seealso: [](ch_snes), `SNES`, `TS`, `SNESSetDivergenceTolerance()`
3810: @*/
3811: PetscErrorCode SNESSetForceIteration(SNES snes, PetscBool force)
3812: {
3813: PetscFunctionBegin;
3815: snes->forceiteration = force;
3816: PetscFunctionReturn(PETSC_SUCCESS);
3817: }
3819: /*@
3820: SNESGetForceIteration - Check whether or not `SNESSolve()` take at least one iteration regardless of the initial residual norm
3822: Logically Collective
3824: Input Parameter:
3825: . snes - the `SNES` context
3827: Output Parameter:
3828: . force - `PETSC_TRUE` requires at least one iteration.
3830: Level: intermediate
3832: .seealso: [](ch_snes), `SNES`, `SNESSetForceIteration()`, `SNESSetDivergenceTolerance()`
3833: @*/
3834: PetscErrorCode SNESGetForceIteration(SNES snes, PetscBool *force)
3835: {
3836: PetscFunctionBegin;
3838: *force = snes->forceiteration;
3839: PetscFunctionReturn(PETSC_SUCCESS);
3840: }
3842: /*@
3843: SNESSetTolerances - Sets various parameters used in `SNES` convergence tests.
3845: Logically Collective
3847: Input Parameters:
3848: + snes - the `SNES` context
3849: . abstol - the absolute convergence tolerance, $ F(x^n) \le abstol $
3850: . rtol - the relative convergence tolerance, $ F(x^n) \le reltol * F(x^0) $
3851: . stol - convergence tolerance in terms of the norm of the change in the solution between steps, || delta x || < stol*|| x ||
3852: . maxit - the maximum number of iterations allowed in the solver, default 50.
3853: - maxf - the maximum number of function evaluations allowed in the solver (use `PETSC_UNLIMITED` indicates no limit), default 10,000
3855: Options Database Keys:
3856: + -snes_atol <abstol> - Sets `abstol`
3857: . -snes_rtol <rtol> - Sets `rtol`
3858: . -snes_stol <stol> - Sets `stol`
3859: . -snes_max_it <maxit> - Sets `maxit`
3860: - -snes_max_funcs <maxf> - Sets `maxf` (use `unlimited` to have no maximum)
3862: Level: intermediate
3864: Note:
3865: All parameters must be non-negative
3867: Use `PETSC_CURRENT` to retain the current value of any parameter and `PETSC_DETERMINE` to use the default value for the given `SNES`.
3868: The default value is the value in the object when its type is set.
3870: Use `PETSC_UNLIMITED` on `maxit` or `maxf` to indicate there is no bound on the number of iterations or number of function evaluations.
3872: Fortran Note:
3873: Use `PETSC_CURRENT_INTEGER`, `PETSC_CURRENT_REAL`, `PETSC_UNLIMITED_INTEGER`, `PETSC_DETERMINE_INTEGER`, or `PETSC_DETERMINE_REAL`
3875: .seealso: [](ch_snes), `SNESSolve()`, `SNES`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`
3876: @*/
3877: PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
3878: {
3879: PetscFunctionBegin;
3887: if (abstol == (PetscReal)PETSC_DETERMINE) {
3888: snes->abstol = snes->default_abstol;
3889: } else if (abstol != (PetscReal)PETSC_CURRENT) {
3890: PetscCheck(abstol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %g must be non-negative", (double)abstol);
3891: snes->abstol = abstol;
3892: }
3894: if (rtol == (PetscReal)PETSC_DETERMINE) {
3895: snes->rtol = snes->default_rtol;
3896: } else if (rtol != (PetscReal)PETSC_CURRENT) {
3897: 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);
3898: snes->rtol = rtol;
3899: }
3901: if (stol == (PetscReal)PETSC_DETERMINE) {
3902: snes->stol = snes->default_stol;
3903: } else if (stol != (PetscReal)PETSC_CURRENT) {
3904: PetscCheck(stol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Step tolerance %g must be non-negative", (double)stol);
3905: snes->stol = stol;
3906: }
3908: if (maxit == PETSC_DETERMINE) {
3909: snes->max_its = snes->default_max_its;
3910: } else if (maxit == PETSC_UNLIMITED) {
3911: snes->max_its = PETSC_INT_MAX;
3912: } else if (maxit != PETSC_CURRENT) {
3913: PetscCheck(maxit >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", maxit);
3914: snes->max_its = maxit;
3915: }
3917: if (maxf == PETSC_DETERMINE) {
3918: snes->max_funcs = snes->default_max_funcs;
3919: } else if (maxf == PETSC_UNLIMITED || maxf == -1) {
3920: snes->max_funcs = PETSC_UNLIMITED;
3921: } else if (maxf != PETSC_CURRENT) {
3922: PetscCheck(maxf >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of function evaluations %" PetscInt_FMT " must be nonnegative", maxf);
3923: snes->max_funcs = maxf;
3924: }
3925: PetscFunctionReturn(PETSC_SUCCESS);
3926: }
3928: /*@
3929: SNESSetDivergenceTolerance - Sets the divergence tolerance used for the `SNES` divergence test.
3931: Logically Collective
3933: Input Parameters:
3934: + snes - the `SNES` context
3935: - divtol - the divergence tolerance. Use `PETSC_UNLIMITED` to deactivate the test. If the residual norm $ F(x^n) \ge divtol * F(x^0) $ the solver
3936: is stopped due to divergence.
3938: Options Database Key:
3939: . -snes_divergence_tolerance <divtol> - Sets `divtol`
3941: Level: intermediate
3943: Notes:
3944: Use `PETSC_DETERMINE` to use the default value from when the object's type was set.
3946: Fortran Note:
3947: Use ``PETSC_DETERMINE_REAL` or `PETSC_UNLIMITED_REAL`
3949: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetTolerances()`, `SNESGetDivergenceTolerance()`
3950: @*/
3951: PetscErrorCode SNESSetDivergenceTolerance(SNES snes, PetscReal divtol)
3952: {
3953: PetscFunctionBegin;
3957: if (divtol == (PetscReal)PETSC_DETERMINE) {
3958: snes->divtol = snes->default_divtol;
3959: } else if (divtol == (PetscReal)PETSC_UNLIMITED || divtol == -1) {
3960: snes->divtol = PETSC_UNLIMITED;
3961: } else if (divtol != (PetscReal)PETSC_CURRENT) {
3962: PetscCheck(divtol >= 1.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Divergence tolerance %g must be greater than 1.0", (double)divtol);
3963: snes->divtol = divtol;
3964: }
3965: PetscFunctionReturn(PETSC_SUCCESS);
3966: }
3968: /*@
3969: SNESGetTolerances - Gets various parameters used in `SNES` convergence tests.
3971: Not Collective
3973: Input Parameter:
3974: . snes - the `SNES` context
3976: Output Parameters:
3977: + atol - the absolute convergence tolerance
3978: . rtol - the relative convergence tolerance
3979: . stol - convergence tolerance in terms of the norm of the change in the solution between steps
3980: . maxit - the maximum number of iterations allowed
3981: - maxf - the maximum number of function evaluations allowed, `PETSC_UNLIMITED` indicates no bound
3983: Level: intermediate
3985: Notes:
3986: See `SNESSetTolerances()` for details on the parameters.
3988: The user can specify `NULL` for any parameter that is not needed.
3990: .seealso: [](ch_snes), `SNES`, `SNESSetTolerances()`
3991: @*/
3992: PetscErrorCode SNESGetTolerances(SNES snes, PetscReal *atol, PetscReal *rtol, PetscReal *stol, PetscInt *maxit, PetscInt *maxf)
3993: {
3994: PetscFunctionBegin;
3996: if (atol) *atol = snes->abstol;
3997: if (rtol) *rtol = snes->rtol;
3998: if (stol) *stol = snes->stol;
3999: if (maxit) *maxit = snes->max_its;
4000: if (maxf) *maxf = snes->max_funcs;
4001: PetscFunctionReturn(PETSC_SUCCESS);
4002: }
4004: /*@
4005: SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.
4007: Not Collective
4009: Input Parameters:
4010: + snes - the `SNES` context
4011: - divtol - divergence tolerance
4013: Level: intermediate
4015: .seealso: [](ch_snes), `SNES`, `SNESSetDivergenceTolerance()`
4016: @*/
4017: PetscErrorCode SNESGetDivergenceTolerance(SNES snes, PetscReal *divtol)
4018: {
4019: PetscFunctionBegin;
4021: if (divtol) *divtol = snes->divtol;
4022: PetscFunctionReturn(PETSC_SUCCESS);
4023: }
4025: PETSC_INTERN PetscErrorCode SNESMonitorRange_Private(SNES, PetscInt, PetscReal *);
4027: PetscErrorCode SNESMonitorLGRange(SNES snes, PetscInt n, PetscReal rnorm, void *monctx)
4028: {
4029: PetscDrawLG lg;
4030: PetscReal x, y, per;
4031: PetscViewer v = (PetscViewer)monctx;
4032: static PetscReal prev; /* should be in the context */
4033: PetscDraw draw;
4035: PetscFunctionBegin;
4037: PetscCall(PetscViewerDrawGetDrawLG(v, 0, &lg));
4038: if (!n) PetscCall(PetscDrawLGReset(lg));
4039: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4040: PetscCall(PetscDrawSetTitle(draw, "Residual norm"));
4041: x = (PetscReal)n;
4042: if (rnorm > 0.0) y = PetscLog10Real(rnorm);
4043: else y = -15.0;
4044: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4045: if (n < 20 || !(n % 5) || snes->reason) {
4046: PetscCall(PetscDrawLGDraw(lg));
4047: PetscCall(PetscDrawLGSave(lg));
4048: }
4050: PetscCall(PetscViewerDrawGetDrawLG(v, 1, &lg));
4051: if (!n) PetscCall(PetscDrawLGReset(lg));
4052: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4053: PetscCall(PetscDrawSetTitle(draw, "% elements > .2*max element"));
4054: PetscCall(SNESMonitorRange_Private(snes, n, &per));
4055: x = (PetscReal)n;
4056: y = 100.0 * per;
4057: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4058: if (n < 20 || !(n % 5) || snes->reason) {
4059: PetscCall(PetscDrawLGDraw(lg));
4060: PetscCall(PetscDrawLGSave(lg));
4061: }
4063: PetscCall(PetscViewerDrawGetDrawLG(v, 2, &lg));
4064: if (!n) {
4065: prev = rnorm;
4066: PetscCall(PetscDrawLGReset(lg));
4067: }
4068: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4069: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm"));
4070: x = (PetscReal)n;
4071: y = (prev - rnorm) / prev;
4072: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4073: if (n < 20 || !(n % 5) || snes->reason) {
4074: PetscCall(PetscDrawLGDraw(lg));
4075: PetscCall(PetscDrawLGSave(lg));
4076: }
4078: PetscCall(PetscViewerDrawGetDrawLG(v, 3, &lg));
4079: if (!n) PetscCall(PetscDrawLGReset(lg));
4080: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4081: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm*(% > .2 max)"));
4082: x = (PetscReal)n;
4083: y = (prev - rnorm) / (prev * per);
4084: if (n > 2) { /*skip initial crazy value */
4085: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4086: }
4087: if (n < 20 || !(n % 5) || snes->reason) {
4088: PetscCall(PetscDrawLGDraw(lg));
4089: PetscCall(PetscDrawLGSave(lg));
4090: }
4091: prev = rnorm;
4092: PetscFunctionReturn(PETSC_SUCCESS);
4093: }
4095: /*@
4096: SNESConverged - Run the convergence test and update the `SNESConvergedReason`.
4098: Collective
4100: Input Parameters:
4101: + snes - the `SNES` context
4102: . it - current iteration
4103: . xnorm - 2-norm of current iterate
4104: . snorm - 2-norm of current step
4105: - fnorm - 2-norm of function
4107: Level: developer
4109: Note:
4110: This routine is called by the `SNESSolve()` implementations.
4111: It does not typically need to be called by the user.
4113: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4114: @*/
4115: PetscErrorCode SNESConverged(SNES snes, PetscInt it, PetscReal xnorm, PetscReal snorm, PetscReal fnorm)
4116: {
4117: PetscFunctionBegin;
4118: if (!snes->reason) {
4119: if (snes->normschedule == SNES_NORM_ALWAYS) PetscUseTypeMethod(snes, converged, it, xnorm, snorm, fnorm, &snes->reason, snes->cnvP);
4120: if (it == snes->max_its && !snes->reason) {
4121: if (snes->normschedule == SNES_NORM_ALWAYS) {
4122: PetscCall(PetscInfo(snes, "Maximum number of iterations has been reached: %" PetscInt_FMT "\n", snes->max_its));
4123: snes->reason = SNES_DIVERGED_MAX_IT;
4124: } else snes->reason = SNES_CONVERGED_ITS;
4125: }
4126: }
4127: PetscFunctionReturn(PETSC_SUCCESS);
4128: }
4130: /*@
4131: SNESMonitor - runs any `SNES` monitor routines provided with `SNESMonitor()` or the options database
4133: Collective
4135: Input Parameters:
4136: + snes - nonlinear solver context obtained from `SNESCreate()`
4137: . iter - current iteration number
4138: - rnorm - current relative norm of the residual
4140: Level: developer
4142: Note:
4143: This routine is called by the `SNESSolve()` implementations.
4144: It does not typically need to be called by the user.
4146: .seealso: [](ch_snes), `SNES`, `SNESMonitorSet()`
4147: @*/
4148: PetscErrorCode SNESMonitor(SNES snes, PetscInt iter, PetscReal rnorm)
4149: {
4150: PetscInt i, n = snes->numbermonitors;
4152: PetscFunctionBegin;
4153: if (n > 0) SNESCheckFunctionNorm(snes, rnorm);
4154: PetscCall(VecLockReadPush(snes->vec_sol));
4155: for (i = 0; i < n; i++) PetscCall((*snes->monitor[i])(snes, iter, rnorm, snes->monitorcontext[i]));
4156: PetscCall(VecLockReadPop(snes->vec_sol));
4157: PetscFunctionReturn(PETSC_SUCCESS);
4158: }
4160: /* ------------ Routines to set performance monitoring options ----------- */
4162: /*MC
4163: SNESMonitorFunction - functional form passed to `SNESMonitorSet()` to monitor convergence of nonlinear solver
4165: Synopsis:
4166: #include <petscsnes.h>
4167: PetscErrorCode SNESMonitorFunction(SNES snes, PetscInt its, PetscReal norm, void *mctx)
4169: Collective
4171: Input Parameters:
4172: + snes - the `SNES` context
4173: . its - iteration number
4174: . norm - 2-norm function value (may be estimated)
4175: - mctx - [optional] monitoring context
4177: Level: advanced
4179: .seealso: [](ch_snes), `SNESMonitorSet()`, `SNESMonitorSet()`, `SNESMonitorGet()`
4180: M*/
4182: /*@C
4183: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
4184: iteration of the `SNES` nonlinear solver to display the iteration's
4185: progress.
4187: Logically Collective
4189: Input Parameters:
4190: + snes - the `SNES` context
4191: . f - the monitor function, for the calling sequence see `SNESMonitorFunction`
4192: . mctx - [optional] user-defined context for private data for the monitor routine (use `NULL` if no context is desired)
4193: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4195: Options Database Keys:
4196: + -snes_monitor - sets `SNESMonitorDefault()`
4197: . -snes_monitor draw::draw_lg - sets line graph monitor,
4198: - -snes_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `SNESMonitorSet()`, but does not cancel those set via
4199: the options database.
4201: Level: intermediate
4203: Note:
4204: Several different monitoring routines may be set by calling
4205: `SNESMonitorSet()` multiple times; all will be called in the
4206: order in which they were set.
4208: Fortran Note:
4209: Only a single monitor function can be set for each `SNES` object
4211: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESMonitorDefault()`, `SNESMonitorCancel()`, `SNESMonitorFunction`, `PetscCtxDestroyFn`
4212: @*/
4213: PetscErrorCode SNESMonitorSet(SNES snes, PetscErrorCode (*f)(SNES, PetscInt, PetscReal, void *), void *mctx, PetscCtxDestroyFn *monitordestroy)
4214: {
4215: PetscInt i;
4216: PetscBool identical;
4218: PetscFunctionBegin;
4220: for (i = 0; i < snes->numbermonitors; i++) {
4221: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))f, mctx, monitordestroy, (PetscErrorCode (*)(void))snes->monitor[i], snes->monitorcontext[i], snes->monitordestroy[i], &identical));
4222: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4223: }
4224: PetscCheck(snes->numbermonitors < MAXSNESMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
4225: snes->monitor[snes->numbermonitors] = f;
4226: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
4227: snes->monitorcontext[snes->numbermonitors++] = mctx;
4228: PetscFunctionReturn(PETSC_SUCCESS);
4229: }
4231: /*@
4232: SNESMonitorCancel - Clears all the monitor functions for a `SNES` object.
4234: Logically Collective
4236: Input Parameter:
4237: . snes - the `SNES` context
4239: Options Database Key:
4240: . -snes_monitor_cancel - cancels all monitors that have been hardwired
4241: into a code by calls to `SNESMonitorSet()`, but does not cancel those
4242: set via the options database
4244: Level: intermediate
4246: Note:
4247: There is no way to clear one specific monitor from a `SNES` object.
4249: .seealso: [](ch_snes), `SNES`, `SNESMonitorGet()`, `SNESMonitorDefault()`, `SNESMonitorSet()`
4250: @*/
4251: PetscErrorCode SNESMonitorCancel(SNES snes)
4252: {
4253: PetscInt i;
4255: PetscFunctionBegin;
4257: for (i = 0; i < snes->numbermonitors; i++) {
4258: if (snes->monitordestroy[i]) PetscCall((*snes->monitordestroy[i])(&snes->monitorcontext[i]));
4259: }
4260: snes->numbermonitors = 0;
4261: PetscFunctionReturn(PETSC_SUCCESS);
4262: }
4264: /*MC
4265: SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver
4267: Synopsis:
4268: #include <petscsnes.h>
4269: PetscErrorCode SNESConvergenceTest(SNES snes, PetscInt it, PetscReal xnorm, PetscReal gnorm, PetscReal f, SNESConvergedReason *reason, void *cctx)
4271: Collective
4273: Input Parameters:
4274: + snes - the `SNES` context
4275: . it - current iteration (0 is the first and is before any Newton step)
4276: . xnorm - 2-norm of current iterate
4277: . gnorm - 2-norm of current step
4278: . f - 2-norm of function
4279: - cctx - [optional] convergence context
4281: Output Parameter:
4282: . reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected
4284: Level: intermediate
4286: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4287: M*/
4289: /*@C
4290: SNESSetConvergenceTest - Sets the function that is to be used
4291: to test for convergence of the nonlinear iterative solution.
4293: Logically Collective
4295: Input Parameters:
4296: + snes - the `SNES` context
4297: . SNESConvergenceTestFunction - routine to test for convergence
4298: . cctx - [optional] context for private data for the convergence routine (may be `NULL`)
4299: - destroy - [optional] destructor for the context (may be `NULL`; `PETSC_NULL_FUNCTION` in Fortran)
4301: Level: advanced
4303: .seealso: [](ch_snes), `SNES`, `SNESConvergedDefault()`, `SNESConvergedSkip()`, `SNESConvergenceTestFunction`
4304: @*/
4305: PetscErrorCode SNESSetConvergenceTest(SNES snes, PetscErrorCode (*SNESConvergenceTestFunction)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *cctx, PetscErrorCode (*destroy)(void *))
4306: {
4307: PetscFunctionBegin;
4309: if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4310: if (snes->ops->convergeddestroy) PetscCall((*snes->ops->convergeddestroy)(snes->cnvP));
4311: snes->ops->converged = SNESConvergenceTestFunction;
4312: snes->ops->convergeddestroy = destroy;
4313: snes->cnvP = cctx;
4314: PetscFunctionReturn(PETSC_SUCCESS);
4315: }
4317: /*@
4318: SNESGetConvergedReason - Gets the reason the `SNES` iteration was stopped, which may be due to convergence, divergence, or stagnation
4320: Not Collective
4322: Input Parameter:
4323: . snes - the `SNES` context
4325: Output Parameter:
4326: . reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` for the individual convergence tests for complete lists
4328: Options Database Key:
4329: . -snes_converged_reason - prints the reason to standard out
4331: Level: intermediate
4333: Note:
4334: Should only be called after the call the `SNESSolve()` is complete, if it is called earlier it returns the value `SNES__CONVERGED_ITERATING`.
4336: .seealso: [](ch_snes), `SNESSolve()`, `SNESSetConvergenceTest()`, `SNESSetConvergedReason()`, `SNESConvergedReason`, `SNESGetConvergedReasonString()`
4337: @*/
4338: PetscErrorCode SNESGetConvergedReason(SNES snes, SNESConvergedReason *reason)
4339: {
4340: PetscFunctionBegin;
4342: PetscAssertPointer(reason, 2);
4343: *reason = snes->reason;
4344: PetscFunctionReturn(PETSC_SUCCESS);
4345: }
4347: /*@C
4348: SNESGetConvergedReasonString - Return a human readable string for `SNESConvergedReason`
4350: Not Collective
4352: Input Parameter:
4353: . snes - the `SNES` context
4355: Output Parameter:
4356: . strreason - a human readable string that describes `SNES` converged reason
4358: Level: beginner
4360: .seealso: [](ch_snes), `SNES`, `SNESGetConvergedReason()`
4361: @*/
4362: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char **strreason)
4363: {
4364: PetscFunctionBegin;
4366: PetscAssertPointer(strreason, 2);
4367: *strreason = SNESConvergedReasons[snes->reason];
4368: PetscFunctionReturn(PETSC_SUCCESS);
4369: }
4371: /*@
4372: SNESSetConvergedReason - Sets the reason the `SNES` iteration was stopped.
4374: Not Collective
4376: Input Parameters:
4377: + snes - the `SNES` context
4378: - reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` or the
4379: manual pages for the individual convergence tests for complete lists
4381: Level: developer
4383: Developer Note:
4384: Called inside the various `SNESSolve()` implementations
4386: .seealso: [](ch_snes), `SNESGetConvergedReason()`, `SNESSetConvergenceTest()`, `SNESConvergedReason`
4387: @*/
4388: PetscErrorCode SNESSetConvergedReason(SNES snes, SNESConvergedReason reason)
4389: {
4390: PetscFunctionBegin;
4392: PetscCheck(!snes->errorifnotconverged || reason > 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_PLIB, "SNES code should have previously errored due to negative reason");
4393: snes->reason = reason;
4394: PetscFunctionReturn(PETSC_SUCCESS);
4395: }
4397: /*@
4398: SNESSetConvergenceHistory - Sets the arrays used to hold the convergence history.
4400: Logically Collective
4402: Input Parameters:
4403: + snes - iterative context obtained from `SNESCreate()`
4404: . a - array to hold history, this array will contain the function norms computed at each step
4405: . its - integer array holds the number of linear iterations for each solve.
4406: . na - size of `a` and `its`
4407: - reset - `PETSC_TRUE` indicates each new nonlinear solve resets the history counter to zero,
4408: else it continues storing new values for new nonlinear solves after the old ones
4410: Level: intermediate
4412: Notes:
4413: If 'a' and 'its' are `NULL` then space is allocated for the history. If 'na' is `PETSC_DECIDE` (or, deprecated, `PETSC_DEFAULT`) then a
4414: default array of length 1,000 is allocated.
4416: This routine is useful, e.g., when running a code for purposes
4417: of accurate performance monitoring, when no I/O should be done
4418: during the section of code that is being timed.
4420: If the arrays run out of space after a number of iterations then the later values are not saved in the history
4422: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergenceHistory()`
4423: @*/
4424: PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)
4425: {
4426: PetscFunctionBegin;
4428: if (a) PetscAssertPointer(a, 2);
4429: if (its) PetscAssertPointer(its, 3);
4430: if (!a) {
4431: if (na == PETSC_DECIDE) na = 1000;
4432: PetscCall(PetscCalloc2(na, &a, na, &its));
4433: snes->conv_hist_alloc = PETSC_TRUE;
4434: }
4435: snes->conv_hist = a;
4436: snes->conv_hist_its = its;
4437: snes->conv_hist_max = (size_t)na;
4438: snes->conv_hist_len = 0;
4439: snes->conv_hist_reset = reset;
4440: PetscFunctionReturn(PETSC_SUCCESS);
4441: }
4443: #if defined(PETSC_HAVE_MATLAB)
4444: #include <engine.h> /* MATLAB include file */
4445: #include <mex.h> /* MATLAB include file */
4447: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4448: {
4449: mxArray *mat;
4450: PetscInt i;
4451: PetscReal *ar;
4453: mat = mxCreateDoubleMatrix(snes->conv_hist_len, 1, mxREAL);
4454: ar = (PetscReal *)mxGetData(mat);
4455: for (i = 0; i < snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4456: return mat;
4457: }
4458: #endif
4460: /*@C
4461: SNESGetConvergenceHistory - Gets the arrays used to hold the convergence history.
4463: Not Collective
4465: Input Parameter:
4466: . snes - iterative context obtained from `SNESCreate()`
4468: Output Parameters:
4469: + a - array to hold history, usually was set with `SNESSetConvergenceHistory()`
4470: . its - integer array holds the number of linear iterations (or
4471: negative if not converged) for each solve.
4472: - na - size of `a` and `its`
4474: Level: intermediate
4476: Note:
4477: This routine is useful, e.g., when running a code for purposes
4478: of accurate performance monitoring, when no I/O should be done
4479: during the section of code that is being timed.
4481: Fortran Notes:
4482: Return the arrays with ``SNESRestoreConvergenceHistory()`
4484: Use the arguments
4485: .vb
4486: PetscReal, pointer :: a(:)
4487: PetscInt, pointer :: its(:)
4488: .ve
4490: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetConvergenceHistory()`
4491: @*/
4492: PetscErrorCode SNESGetConvergenceHistory(SNES snes, PetscReal *a[], PetscInt *its[], PetscInt *na)
4493: {
4494: PetscFunctionBegin;
4496: if (a) *a = snes->conv_hist;
4497: if (its) *its = snes->conv_hist_its;
4498: if (na) *na = (PetscInt)snes->conv_hist_len;
4499: PetscFunctionReturn(PETSC_SUCCESS);
4500: }
4502: /*@C
4503: SNESSetUpdate - Sets the general-purpose update function called
4504: at the beginning of every iteration of the nonlinear solve. Specifically
4505: it is called just before the Jacobian is "evaluated" and after the function
4506: evaluation.
4508: Logically Collective
4510: Input Parameters:
4511: + snes - The nonlinear solver context
4512: - func - The update function; for calling sequence see `SNESUpdateFn`
4514: Level: advanced
4516: Notes:
4517: 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
4518: to `SNESSetFunction()`, or `SNESSetPicard()`
4519: This is not used by most users, and it is intended to provide a general hook that is run
4520: right before the direction step is computed.
4522: Users are free to modify the current residual vector,
4523: the current linearization point, or any other vector associated to the specific solver used.
4524: If such modifications take place, it is the user responsibility to update all the relevant
4525: vectors. For example, if one is adjusting the model parameters at each Newton step their code may look like
4526: .vb
4527: PetscErrorCode update(SNES snes, PetscInt iteration)
4528: {
4529: PetscFunctionBeginUser;
4530: if (iteration > 0) {
4531: // update the model parameters here
4532: Vec x,f;
4533: PetscCall(SNESGetSolution(snes,&x));
4534: PetcCall(SNESGetFunction(snes,&f,NULL,NULL));
4535: PetscCall(SNESComputeFunction(snes,x,f));
4536: }
4537: PetscFunctionReturn(PETSC_SUCCESS);
4538: }
4539: .ve
4541: There are a variety of function hooks one many set that are called at different stages of the nonlinear solution process, see the functions listed below.
4543: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetJacobian()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRSetPostCheck()`,
4544: `SNESMonitorSet()`
4545: @*/
4546: PetscErrorCode SNESSetUpdate(SNES snes, SNESUpdateFn *func)
4547: {
4548: PetscFunctionBegin;
4550: snes->ops->update = func;
4551: PetscFunctionReturn(PETSC_SUCCESS);
4552: }
4554: /*@
4555: SNESConvergedReasonView - Displays the reason a `SNES` solve converged or diverged to a viewer
4557: Collective
4559: Input Parameters:
4560: + snes - iterative context obtained from `SNESCreate()`
4561: - viewer - the viewer to display the reason
4563: Options Database Keys:
4564: + -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4565: - -snes_converged_reason ::failed - only print reason and number of iterations when diverged
4567: Level: beginner
4569: Note:
4570: To change the format of the output call `PetscViewerPushFormat`(viewer,format) before this call. Use `PETSC_VIEWER_DEFAULT` for the default,
4571: use `PETSC_VIEWER_FAILED` to only display a reason if it fails.
4573: .seealso: [](ch_snes), `SNESConvergedReason`, `PetscViewer`, `SNES`,
4574: `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`, `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`,
4575: `SNESConvergedReasonViewFromOptions()`,
4576: `PetscViewerPushFormat()`, `PetscViewerPopFormat()`
4577: @*/
4578: PetscErrorCode SNESConvergedReasonView(SNES snes, PetscViewer viewer)
4579: {
4580: PetscViewerFormat format;
4581: PetscBool isAscii;
4583: PetscFunctionBegin;
4584: if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4585: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isAscii));
4586: if (isAscii) {
4587: PetscCall(PetscViewerGetFormat(viewer, &format));
4588: PetscCall(PetscViewerASCIIAddTab(viewer, ((PetscObject)snes)->tablevel + 1));
4589: if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4590: DM dm;
4591: Vec u;
4592: PetscDS prob;
4593: PetscInt Nf, f;
4594: PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4595: void **exactCtx;
4596: PetscReal error;
4598: PetscCall(SNESGetDM(snes, &dm));
4599: PetscCall(SNESGetSolution(snes, &u));
4600: PetscCall(DMGetDS(dm, &prob));
4601: PetscCall(PetscDSGetNumFields(prob, &Nf));
4602: PetscCall(PetscMalloc2(Nf, &exactSol, Nf, &exactCtx));
4603: for (f = 0; f < Nf; ++f) PetscCall(PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]));
4604: PetscCall(DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error));
4605: PetscCall(PetscFree2(exactSol, exactCtx));
4606: if (error < 1.0e-11) PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n"));
4607: else PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", (double)error));
4608: }
4609: if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4610: if (((PetscObject)snes)->prefix) {
4611: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve converged due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4612: } else {
4613: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve converged due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4614: }
4615: } else if (snes->reason <= 0) {
4616: if (((PetscObject)snes)->prefix) {
4617: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve did not converge due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4618: } else {
4619: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve did not converge due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4620: }
4621: }
4622: PetscCall(PetscViewerASCIISubtractTab(viewer, ((PetscObject)snes)->tablevel + 1));
4623: }
4624: PetscFunctionReturn(PETSC_SUCCESS);
4625: }
4627: /*@C
4628: SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4629: end of the nonlinear solver to display the convergence reason of the nonlinear solver.
4631: Logically Collective
4633: Input Parameters:
4634: + snes - the `SNES` context
4635: . f - the `SNESConvergedReason` view function
4636: . vctx - [optional] user-defined context for private data for the `SNESConvergedReason` view function (use `NULL` if no context is desired)
4637: - reasonviewdestroy - [optional] routine that frees the context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4639: Calling sequence of `f`:
4640: + snes - the `SNES` context
4641: - vctx - [optional] context for private data for the function
4643: Options Database Keys:
4644: + -snes_converged_reason - sets a default `SNESConvergedReasonView()`
4645: - -snes_converged_reason_view_cancel - cancels all converged reason viewers that have been hardwired into a code by
4646: calls to `SNESConvergedReasonViewSet()`, but does not cancel those set via the options database.
4648: Level: intermediate
4650: Note:
4651: Several different converged reason view routines may be set by calling
4652: `SNESConvergedReasonViewSet()` multiple times; all will be called in the
4653: order in which they were set.
4655: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESConvergedReason`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`, `SNESConvergedReasonViewCancel()`,
4656: `PetscCtxDestroyFn`
4657: @*/
4658: PetscErrorCode SNESConvergedReasonViewSet(SNES snes, PetscErrorCode (*f)(SNES snes, void *vctx), void *vctx, PetscCtxDestroyFn *reasonviewdestroy)
4659: {
4660: PetscInt i;
4661: PetscBool identical;
4663: PetscFunctionBegin;
4665: for (i = 0; i < snes->numberreasonviews; i++) {
4666: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))f, vctx, reasonviewdestroy, (PetscErrorCode (*)(void))snes->reasonview[i], snes->reasonviewcontext[i], snes->reasonviewdestroy[i], &identical));
4667: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4668: }
4669: PetscCheck(snes->numberreasonviews < MAXSNESREASONVIEWS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many SNES reasonview set");
4670: snes->reasonview[snes->numberreasonviews] = f;
4671: snes->reasonviewdestroy[snes->numberreasonviews] = reasonviewdestroy;
4672: snes->reasonviewcontext[snes->numberreasonviews++] = vctx;
4673: PetscFunctionReturn(PETSC_SUCCESS);
4674: }
4676: /*@
4677: SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a `SNESConvergedReason` is to be viewed at the end of `SNESSolve()`
4678: All the user-provided viewer routines set with `SNESConvergedReasonViewSet()` will be called, if they exist.
4680: Collective
4682: Input Parameter:
4683: . snes - the `SNES` object
4685: Level: advanced
4687: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESConvergedReasonViewSet()`, `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`,
4688: `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`
4689: @*/
4690: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4691: {
4692: static PetscBool incall = PETSC_FALSE;
4694: PetscFunctionBegin;
4695: if (incall) PetscFunctionReturn(PETSC_SUCCESS);
4696: incall = PETSC_TRUE;
4698: /* All user-provided viewers are called first, if they exist. */
4699: for (PetscInt i = 0; i < snes->numberreasonviews; i++) PetscCall((*snes->reasonview[i])(snes, snes->reasonviewcontext[i]));
4701: /* Call PETSc default routine if users ask for it */
4702: if (snes->convergedreasonviewer) {
4703: PetscCall(PetscViewerPushFormat(snes->convergedreasonviewer, snes->convergedreasonformat));
4704: PetscCall(SNESConvergedReasonView(snes, snes->convergedreasonviewer));
4705: PetscCall(PetscViewerPopFormat(snes->convergedreasonviewer));
4706: }
4707: incall = PETSC_FALSE;
4708: PetscFunctionReturn(PETSC_SUCCESS);
4709: }
4711: /*@
4712: SNESSolve - Solves a nonlinear system $F(x) = b $ associated with a `SNES` object
4714: Collective
4716: Input Parameters:
4717: + snes - the `SNES` context
4718: . b - the constant part of the equation $F(x) = b$, or `NULL` to use zero.
4719: - x - the solution vector.
4721: Level: beginner
4723: Note:
4724: The user should initialize the vector, `x`, with the initial guess
4725: for the nonlinear solve prior to calling `SNESSolve()` .
4727: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFunction()`, `SNESSetJacobian()`, `SNESSetGridSequence()`, `SNESGetSolution()`,
4728: `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRGetPreCheck()`, `SNESNewtonTRSetPostCheck()`, `SNESNewtonTRGetPostCheck()`,
4729: `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`
4730: @*/
4731: PetscErrorCode SNESSolve(SNES snes, Vec b, Vec x)
4732: {
4733: PetscBool flg;
4734: PetscInt grid;
4735: Vec xcreated = NULL;
4736: DM dm;
4738: PetscFunctionBegin;
4741: if (x) PetscCheckSameComm(snes, 1, x, 3);
4743: if (b) PetscCheckSameComm(snes, 1, b, 2);
4745: /* High level operations using the nonlinear solver */
4746: {
4747: PetscViewer viewer;
4748: PetscViewerFormat format;
4749: PetscInt num;
4750: PetscBool flg;
4751: static PetscBool incall = PETSC_FALSE;
4753: if (!incall) {
4754: /* Estimate the convergence rate of the discretization */
4755: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg));
4756: if (flg) {
4757: PetscConvEst conv;
4758: DM dm;
4759: PetscReal *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4760: PetscInt Nf;
4762: incall = PETSC_TRUE;
4763: PetscCall(SNESGetDM(snes, &dm));
4764: PetscCall(DMGetNumFields(dm, &Nf));
4765: PetscCall(PetscCalloc1(Nf, &alpha));
4766: PetscCall(PetscConvEstCreate(PetscObjectComm((PetscObject)snes), &conv));
4767: PetscCall(PetscConvEstSetSolver(conv, (PetscObject)snes));
4768: PetscCall(PetscConvEstSetFromOptions(conv));
4769: PetscCall(PetscConvEstSetUp(conv));
4770: PetscCall(PetscConvEstGetConvRate(conv, alpha));
4771: PetscCall(PetscViewerPushFormat(viewer, format));
4772: PetscCall(PetscConvEstRateView(conv, alpha, viewer));
4773: PetscCall(PetscViewerPopFormat(viewer));
4774: PetscCall(PetscViewerDestroy(&viewer));
4775: PetscCall(PetscConvEstDestroy(&conv));
4776: PetscCall(PetscFree(alpha));
4777: incall = PETSC_FALSE;
4778: }
4779: /* Adaptively refine the initial grid */
4780: num = 1;
4781: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_initial", &num, &flg));
4782: if (flg) {
4783: DMAdaptor adaptor;
4785: incall = PETSC_TRUE;
4786: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4787: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4788: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4789: PetscCall(DMAdaptorSetFromOptions(adaptor));
4790: PetscCall(DMAdaptorSetUp(adaptor));
4791: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x));
4792: PetscCall(DMAdaptorDestroy(&adaptor));
4793: incall = PETSC_FALSE;
4794: }
4795: /* Use grid sequencing to adapt */
4796: num = 0;
4797: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_sequence", &num, NULL));
4798: if (num) {
4799: DMAdaptor adaptor;
4800: const char *prefix;
4802: incall = PETSC_TRUE;
4803: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4804: PetscCall(SNESGetOptionsPrefix(snes, &prefix));
4805: PetscCall(DMAdaptorSetOptionsPrefix(adaptor, prefix));
4806: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4807: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4808: PetscCall(DMAdaptorSetFromOptions(adaptor));
4809: PetscCall(DMAdaptorSetUp(adaptor));
4810: PetscCall(PetscObjectViewFromOptions((PetscObject)adaptor, NULL, "-snes_adapt_view"));
4811: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x));
4812: PetscCall(DMAdaptorDestroy(&adaptor));
4813: incall = PETSC_FALSE;
4814: }
4815: }
4816: }
4817: if (!x) x = snes->vec_sol;
4818: if (!x) {
4819: PetscCall(SNESGetDM(snes, &dm));
4820: PetscCall(DMCreateGlobalVector(dm, &xcreated));
4821: x = xcreated;
4822: }
4823: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view_pre"));
4825: for (grid = 0; grid < snes->gridsequence; grid++) PetscCall(PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4826: for (grid = 0; grid < snes->gridsequence + 1; grid++) {
4827: /* set solution vector */
4828: if (!grid) PetscCall(PetscObjectReference((PetscObject)x));
4829: PetscCall(VecDestroy(&snes->vec_sol));
4830: snes->vec_sol = x;
4831: PetscCall(SNESGetDM(snes, &dm));
4833: /* set affine vector if provided */
4834: if (b) PetscCall(PetscObjectReference((PetscObject)b));
4835: PetscCall(VecDestroy(&snes->vec_rhs));
4836: snes->vec_rhs = b;
4838: 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");
4839: PetscCheck(snes->vec_func != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be function vector");
4840: PetscCheck(snes->vec_rhs != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be right-hand side vector");
4841: if (!snes->vec_sol_update /* && snes->vec_sol */) PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_sol_update));
4842: PetscCall(DMShellSetGlobalVector(dm, snes->vec_sol));
4843: PetscCall(SNESSetUp(snes));
4845: if (!grid) {
4846: if (snes->ops->computeinitialguess) PetscCallBack("SNES callback compute initial guess", (*snes->ops->computeinitialguess)(snes, snes->vec_sol, snes->initialguessP));
4847: }
4849: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4850: PetscCall(SNESResetCounters(snes));
4851: snes->reason = SNES_CONVERGED_ITERATING;
4852: PetscCall(PetscLogEventBegin(SNES_Solve, snes, 0, 0, 0));
4853: PetscUseTypeMethod(snes, solve);
4854: PetscCall(PetscLogEventEnd(SNES_Solve, snes, 0, 0, 0));
4855: PetscCheck(snes->reason, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Internal error, solver %s returned without setting converged reason", ((PetscObject)snes)->type_name);
4856: snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */
4858: if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4859: if (snes->lagpre_persist) snes->pre_iter += snes->iter;
4861: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_test_local_min", NULL, NULL, &flg));
4862: if (flg && !PetscPreLoadingOn) PetscCall(SNESTestLocalMin(snes));
4863: /* Call converged reason views. This may involve user-provided viewers as well */
4864: PetscCall(SNESConvergedReasonViewFromOptions(snes));
4866: if (snes->errorifnotconverged) PetscCheck(snes->reason >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_NOT_CONVERGED, "SNESSolve has not converged");
4867: if (snes->reason < 0) break;
4868: if (grid < snes->gridsequence) {
4869: DM fine;
4870: Vec xnew;
4871: Mat interp;
4873: PetscCall(DMRefine(snes->dm, PetscObjectComm((PetscObject)snes), &fine));
4874: PetscCheck(fine, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "DMRefine() did not perform any refinement, cannot continue grid sequencing");
4875: PetscCall(DMGetCoordinatesLocalSetUp(fine));
4876: PetscCall(DMCreateInterpolation(snes->dm, fine, &interp, NULL));
4877: PetscCall(DMCreateGlobalVector(fine, &xnew));
4878: PetscCall(MatInterpolate(interp, x, xnew));
4879: PetscCall(DMInterpolate(snes->dm, interp, fine));
4880: PetscCall(MatDestroy(&interp));
4881: x = xnew;
4883: PetscCall(SNESReset(snes));
4884: PetscCall(SNESSetDM(snes, fine));
4885: PetscCall(SNESResetFromOptions(snes));
4886: PetscCall(DMDestroy(&fine));
4887: PetscCall(PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4888: }
4889: }
4890: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view"));
4891: PetscCall(VecViewFromOptions(snes->vec_sol, (PetscObject)snes, "-snes_view_solution"));
4892: PetscCall(DMMonitor(snes->dm));
4893: PetscCall(SNESMonitorPauseFinal_Internal(snes));
4895: PetscCall(VecDestroy(&xcreated));
4896: PetscCall(PetscObjectSAWsBlock((PetscObject)snes));
4897: PetscFunctionReturn(PETSC_SUCCESS);
4898: }
4900: /* --------- Internal routines for SNES Package --------- */
4902: /*@
4903: SNESSetType - Sets the algorithm/method to be used to solve the nonlinear system with the given `SNES`
4905: Collective
4907: Input Parameters:
4908: + snes - the `SNES` context
4909: - type - a known method
4911: Options Database Key:
4912: . -snes_type <type> - Sets the method; use -help for a list
4913: of available methods (for instance, newtonls or newtontr)
4915: Level: intermediate
4917: Notes:
4918: See `SNESType` for available methods (for instance)
4919: + `SNESNEWTONLS` - Newton's method with line search
4920: (systems of nonlinear equations)
4921: - `SNESNEWTONTR` - Newton's method with trust region
4922: (systems of nonlinear equations)
4924: Normally, it is best to use the `SNESSetFromOptions()` command and then
4925: set the `SNES` solver type from the options database rather than by using
4926: this routine. Using the options database provides the user with
4927: maximum flexibility in evaluating the many nonlinear solvers.
4928: The `SNESSetType()` routine is provided for those situations where it
4929: is necessary to set the nonlinear solver independently of the command
4930: line or options database. This might be the case, for example, when
4931: the choice of solver changes during the execution of the program,
4932: and the user's application is taking responsibility for choosing the
4933: appropriate method.
4935: Developer Note:
4936: `SNESRegister()` adds a constructor for a new `SNESType` to `SNESList`, `SNESSetType()` locates
4937: the constructor in that list and calls it to create the specific object.
4939: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESType`, `SNESCreate()`, `SNESDestroy()`, `SNESGetType()`, `SNESSetFromOptions()`
4940: @*/
4941: PetscErrorCode SNESSetType(SNES snes, SNESType type)
4942: {
4943: PetscBool match;
4944: PetscErrorCode (*r)(SNES);
4946: PetscFunctionBegin;
4948: PetscAssertPointer(type, 2);
4950: PetscCall(PetscObjectTypeCompare((PetscObject)snes, type, &match));
4951: if (match) PetscFunctionReturn(PETSC_SUCCESS);
4953: PetscCall(PetscFunctionListFind(SNESList, type, &r));
4954: PetscCheck(r, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested SNES type %s", type);
4955: /* Destroy the previous private SNES context */
4956: PetscTryTypeMethod(snes, destroy);
4957: /* Reinitialize type-specific function pointers in SNESOps structure */
4958: snes->ops->reset = NULL;
4959: snes->ops->setup = NULL;
4960: snes->ops->solve = NULL;
4961: snes->ops->view = NULL;
4962: snes->ops->setfromoptions = NULL;
4963: snes->ops->destroy = NULL;
4965: /* It may happen the user has customized the line search before calling SNESSetType */
4966: if (((PetscObject)snes)->type_name) PetscCall(SNESLineSearchDestroy(&snes->linesearch));
4968: /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4969: snes->setupcalled = PETSC_FALSE;
4971: PetscCall(PetscObjectChangeTypeName((PetscObject)snes, type));
4972: PetscCall((*r)(snes));
4973: PetscFunctionReturn(PETSC_SUCCESS);
4974: }
4976: /*@
4977: SNESGetType - Gets the `SNES` method type and name (as a string).
4979: Not Collective
4981: Input Parameter:
4982: . snes - nonlinear solver context
4984: Output Parameter:
4985: . type - `SNES` method (a character string)
4987: Level: intermediate
4989: .seealso: [](ch_snes), `SNESSetType()`, `SNESType`, `SNESSetFromOptions()`, `SNES`
4990: @*/
4991: PetscErrorCode SNESGetType(SNES snes, SNESType *type)
4992: {
4993: PetscFunctionBegin;
4995: PetscAssertPointer(type, 2);
4996: *type = ((PetscObject)snes)->type_name;
4997: PetscFunctionReturn(PETSC_SUCCESS);
4998: }
5000: /*@
5001: SNESSetSolution - Sets the solution vector for use by the `SNES` routines.
5003: Logically Collective
5005: Input Parameters:
5006: + snes - the `SNES` context obtained from `SNESCreate()`
5007: - u - the solution vector
5009: Level: beginner
5011: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetSolution()`, `Vec`
5012: @*/
5013: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
5014: {
5015: DM dm;
5017: PetscFunctionBegin;
5020: PetscCall(PetscObjectReference((PetscObject)u));
5021: PetscCall(VecDestroy(&snes->vec_sol));
5023: snes->vec_sol = u;
5025: PetscCall(SNESGetDM(snes, &dm));
5026: PetscCall(DMShellSetGlobalVector(dm, u));
5027: PetscFunctionReturn(PETSC_SUCCESS);
5028: }
5030: /*@
5031: SNESGetSolution - Returns the vector where the approximate solution is
5032: stored. This is the fine grid solution when using `SNESSetGridSequence()`.
5034: Not Collective, but `x` is parallel if `snes` is parallel
5036: Input Parameter:
5037: . snes - the `SNES` context
5039: Output Parameter:
5040: . x - the solution
5042: Level: intermediate
5044: .seealso: [](ch_snes), `SNESSetSolution()`, `SNESSolve()`, `SNES`, `SNESGetSolutionUpdate()`, `SNESGetFunction()`
5045: @*/
5046: PetscErrorCode SNESGetSolution(SNES snes, Vec *x)
5047: {
5048: PetscFunctionBegin;
5050: PetscAssertPointer(x, 2);
5051: *x = snes->vec_sol;
5052: PetscFunctionReturn(PETSC_SUCCESS);
5053: }
5055: /*@
5056: SNESGetSolutionUpdate - Returns the vector where the solution update is
5057: stored.
5059: Not Collective, but `x` is parallel if `snes` is parallel
5061: Input Parameter:
5062: . snes - the `SNES` context
5064: Output Parameter:
5065: . x - the solution update
5067: Level: advanced
5069: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`
5070: @*/
5071: PetscErrorCode SNESGetSolutionUpdate(SNES snes, Vec *x)
5072: {
5073: PetscFunctionBegin;
5075: PetscAssertPointer(x, 2);
5076: *x = snes->vec_sol_update;
5077: PetscFunctionReturn(PETSC_SUCCESS);
5078: }
5080: /*@C
5081: SNESGetFunction - Returns the function that defines the nonlinear system set with `SNESSetFunction()`
5083: Not Collective, but `r` is parallel if `snes` is parallel. Collective if `r` is requested, but has not been created yet.
5085: Input Parameter:
5086: . snes - the `SNES` context
5088: Output Parameters:
5089: + r - the vector that is used to store residuals (or `NULL` if you don't want it)
5090: . f - the function (or `NULL` if you don't want it); for calling sequence see `SNESFunctionFn`
5091: - ctx - the function context (or `NULL` if you don't want it)
5093: Level: advanced
5095: Note:
5096: The vector `r` DOES NOT, in general, contain the current value of the `SNES` nonlinear function
5098: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetSolution()`, `SNESFunctionFn`
5099: @*/
5100: PetscErrorCode SNESGetFunction(SNES snes, Vec *r, SNESFunctionFn **f, void **ctx)
5101: {
5102: DM dm;
5104: PetscFunctionBegin;
5106: if (r) {
5107: if (!snes->vec_func) {
5108: if (snes->vec_rhs) {
5109: PetscCall(VecDuplicate(snes->vec_rhs, &snes->vec_func));
5110: } else if (snes->vec_sol) {
5111: PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_func));
5112: } else if (snes->dm) {
5113: PetscCall(DMCreateGlobalVector(snes->dm, &snes->vec_func));
5114: }
5115: }
5116: *r = snes->vec_func;
5117: }
5118: PetscCall(SNESGetDM(snes, &dm));
5119: PetscCall(DMSNESGetFunction(dm, f, ctx));
5120: PetscFunctionReturn(PETSC_SUCCESS);
5121: }
5123: /*@C
5124: SNESGetNGS - Returns the function and context set with `SNESSetNGS()`
5126: Input Parameter:
5127: . snes - the `SNES` context
5129: Output Parameters:
5130: + f - the function (or `NULL`) see `SNESNGSFn` for calling sequence
5131: - ctx - the function context (or `NULL`)
5133: Level: advanced
5135: .seealso: [](ch_snes), `SNESSetNGS()`, `SNESGetFunction()`, `SNESNGSFn`
5136: @*/
5137: PetscErrorCode SNESGetNGS(SNES snes, SNESNGSFn **f, void **ctx)
5138: {
5139: DM dm;
5141: PetscFunctionBegin;
5143: PetscCall(SNESGetDM(snes, &dm));
5144: PetscCall(DMSNESGetNGS(dm, f, ctx));
5145: PetscFunctionReturn(PETSC_SUCCESS);
5146: }
5148: /*@
5149: SNESSetOptionsPrefix - Sets the prefix used for searching for all
5150: `SNES` options in the database.
5152: Logically Collective
5154: Input Parameters:
5155: + snes - the `SNES` context
5156: - prefix - the prefix to prepend to all option names
5158: Level: advanced
5160: Note:
5161: A hyphen (-) must NOT be given at the beginning of the prefix name.
5162: The first character of all runtime options is AUTOMATICALLY the hyphen.
5164: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESAppendOptionsPrefix()`
5165: @*/
5166: PetscErrorCode SNESSetOptionsPrefix(SNES snes, const char prefix[])
5167: {
5168: PetscFunctionBegin;
5170: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes, prefix));
5171: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5172: if (snes->linesearch) {
5173: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5174: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch, prefix));
5175: }
5176: PetscCall(KSPSetOptionsPrefix(snes->ksp, prefix));
5177: PetscFunctionReturn(PETSC_SUCCESS);
5178: }
5180: /*@
5181: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
5182: `SNES` options in the database.
5184: Logically Collective
5186: Input Parameters:
5187: + snes - the `SNES` context
5188: - prefix - the prefix to prepend to all option names
5190: Level: advanced
5192: Note:
5193: A hyphen (-) must NOT be given at the beginning of the prefix name.
5194: The first character of all runtime options is AUTOMATICALLY the hyphen.
5196: .seealso: [](ch_snes), `SNESGetOptionsPrefix()`, `SNESSetOptionsPrefix()`
5197: @*/
5198: PetscErrorCode SNESAppendOptionsPrefix(SNES snes, const char prefix[])
5199: {
5200: PetscFunctionBegin;
5202: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes, prefix));
5203: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5204: if (snes->linesearch) {
5205: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5206: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch, prefix));
5207: }
5208: PetscCall(KSPAppendOptionsPrefix(snes->ksp, prefix));
5209: PetscFunctionReturn(PETSC_SUCCESS);
5210: }
5212: /*@
5213: SNESGetOptionsPrefix - Gets the prefix used for searching for all
5214: `SNES` options in the database.
5216: Not Collective
5218: Input Parameter:
5219: . snes - the `SNES` context
5221: Output Parameter:
5222: . prefix - pointer to the prefix string used
5224: Level: advanced
5226: .seealso: [](ch_snes), `SNES`, `SNESSetOptionsPrefix()`, `SNESAppendOptionsPrefix()`
5227: @*/
5228: PetscErrorCode SNESGetOptionsPrefix(SNES snes, const char *prefix[])
5229: {
5230: PetscFunctionBegin;
5232: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, prefix));
5233: PetscFunctionReturn(PETSC_SUCCESS);
5234: }
5236: /*@C
5237: SNESRegister - Adds a method to the nonlinear solver package.
5239: Not Collective
5241: Input Parameters:
5242: + sname - name of a new user-defined solver
5243: - function - routine to create method context
5245: Level: advanced
5247: Note:
5248: `SNESRegister()` may be called multiple times to add several user-defined solvers.
5250: Example Usage:
5251: .vb
5252: SNESRegister("my_solver", MySolverCreate);
5253: .ve
5255: Then, your solver can be chosen with the procedural interface via
5256: .vb
5257: SNESSetType(snes, "my_solver")
5258: .ve
5259: or at runtime via the option
5260: .vb
5261: -snes_type my_solver
5262: .ve
5264: .seealso: [](ch_snes), `SNESRegisterAll()`, `SNESRegisterDestroy()`
5265: @*/
5266: PetscErrorCode SNESRegister(const char sname[], PetscErrorCode (*function)(SNES))
5267: {
5268: PetscFunctionBegin;
5269: PetscCall(SNESInitializePackage());
5270: PetscCall(PetscFunctionListAdd(&SNESList, sname, function));
5271: PetscFunctionReturn(PETSC_SUCCESS);
5272: }
5274: PetscErrorCode SNESTestLocalMin(SNES snes)
5275: {
5276: PetscInt N, i, j;
5277: Vec u, uh, fh;
5278: PetscScalar value;
5279: PetscReal norm;
5281: PetscFunctionBegin;
5282: PetscCall(SNESGetSolution(snes, &u));
5283: PetscCall(VecDuplicate(u, &uh));
5284: PetscCall(VecDuplicate(u, &fh));
5286: /* currently only works for sequential */
5287: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "Testing FormFunction() for local min\n"));
5288: PetscCall(VecGetSize(u, &N));
5289: for (i = 0; i < N; i++) {
5290: PetscCall(VecCopy(u, uh));
5291: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "i = %" PetscInt_FMT "\n", i));
5292: for (j = -10; j < 11; j++) {
5293: value = PetscSign(j) * PetscExpReal(PetscAbs(j) - 10.0);
5294: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5295: PetscCall(SNESComputeFunction(snes, uh, fh));
5296: PetscCall(VecNorm(fh, NORM_2, &norm));
5297: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), " j norm %" PetscInt_FMT " %18.16e\n", j, (double)norm));
5298: value = -value;
5299: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5300: }
5301: }
5302: PetscCall(VecDestroy(&uh));
5303: PetscCall(VecDestroy(&fh));
5304: PetscFunctionReturn(PETSC_SUCCESS);
5305: }
5307: /*@
5308: SNESKSPSetUseEW - Sets `SNES` to the use Eisenstat-Walker method for
5309: computing relative tolerance for linear solvers within an inexact
5310: Newton method.
5312: Logically Collective
5314: Input Parameters:
5315: + snes - `SNES` context
5316: - flag - `PETSC_TRUE` or `PETSC_FALSE`
5318: Options Database Keys:
5319: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5320: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
5321: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5322: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5323: . -snes_ksp_ew_gamma <gamma> - Sets gamma
5324: . -snes_ksp_ew_alpha <alpha> - Sets alpha
5325: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5326: - -snes_ksp_ew_threshold <threshold> - Sets threshold
5328: Level: advanced
5330: Note:
5331: The default is to use a constant relative tolerance for
5332: the inner linear solvers. Alternatively, one can use the
5333: Eisenstat-Walker method {cite}`ew96`, where the relative convergence tolerance
5334: is reset at each Newton iteration according progress of the nonlinear
5335: solver.
5337: .seealso: [](ch_snes), `KSP`, `SNES`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5338: @*/
5339: PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)
5340: {
5341: PetscFunctionBegin;
5344: snes->ksp_ewconv = flag;
5345: PetscFunctionReturn(PETSC_SUCCESS);
5346: }
5348: /*@
5349: SNESKSPGetUseEW - Gets if `SNES` is using Eisenstat-Walker method
5350: for computing relative tolerance for linear solvers within an
5351: inexact Newton method.
5353: Not Collective
5355: Input Parameter:
5356: . snes - `SNES` context
5358: Output Parameter:
5359: . flag - `PETSC_TRUE` or `PETSC_FALSE`
5361: Level: advanced
5363: .seealso: [](ch_snes), `SNESKSPSetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5364: @*/
5365: PetscErrorCode SNESKSPGetUseEW(SNES snes, PetscBool *flag)
5366: {
5367: PetscFunctionBegin;
5369: PetscAssertPointer(flag, 2);
5370: *flag = snes->ksp_ewconv;
5371: PetscFunctionReturn(PETSC_SUCCESS);
5372: }
5374: /*@
5375: SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5376: convergence criteria for the linear solvers within an inexact
5377: Newton method.
5379: Logically Collective
5381: Input Parameters:
5382: + snes - `SNES` context
5383: . version - version 1, 2 (default is 2), 3 or 4
5384: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5385: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5386: . gamma - multiplicative factor for version 2 rtol computation
5387: (0 <= gamma2 <= 1)
5388: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5389: . alpha2 - power for safeguard
5390: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5392: Level: advanced
5394: Notes:
5395: Version 3 was contributed by Luis Chacon, June 2006.
5397: Use `PETSC_CURRENT` to retain the default for any of the parameters.
5399: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`
5400: @*/
5401: PetscErrorCode SNESKSPSetParametersEW(SNES snes, PetscInt version, PetscReal rtol_0, PetscReal rtol_max, PetscReal gamma, PetscReal alpha, PetscReal alpha2, PetscReal threshold)
5402: {
5403: SNESKSPEW *kctx;
5405: PetscFunctionBegin;
5407: kctx = (SNESKSPEW *)snes->kspconvctx;
5408: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5417: if (version != PETSC_CURRENT) kctx->version = version;
5418: if (rtol_0 != (PetscReal)PETSC_CURRENT) kctx->rtol_0 = rtol_0;
5419: if (rtol_max != (PetscReal)PETSC_CURRENT) kctx->rtol_max = rtol_max;
5420: if (gamma != (PetscReal)PETSC_CURRENT) kctx->gamma = gamma;
5421: if (alpha != (PetscReal)PETSC_CURRENT) kctx->alpha = alpha;
5422: if (alpha2 != (PetscReal)PETSC_CURRENT) kctx->alpha2 = alpha2;
5423: if (threshold != (PetscReal)PETSC_CURRENT) kctx->threshold = threshold;
5425: 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);
5426: 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);
5427: 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);
5428: 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);
5429: 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);
5430: 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);
5431: PetscFunctionReturn(PETSC_SUCCESS);
5432: }
5434: /*@
5435: SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5436: convergence criteria for the linear solvers within an inexact
5437: Newton method.
5439: Not Collective
5441: Input Parameter:
5442: . snes - `SNES` context
5444: Output Parameters:
5445: + version - version 1, 2 (default is 2), 3 or 4
5446: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5447: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5448: . gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5449: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5450: . alpha2 - power for safeguard
5451: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5453: Level: advanced
5455: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPSetParametersEW()`
5456: @*/
5457: PetscErrorCode SNESKSPGetParametersEW(SNES snes, PetscInt *version, PetscReal *rtol_0, PetscReal *rtol_max, PetscReal *gamma, PetscReal *alpha, PetscReal *alpha2, PetscReal *threshold)
5458: {
5459: SNESKSPEW *kctx;
5461: PetscFunctionBegin;
5463: kctx = (SNESKSPEW *)snes->kspconvctx;
5464: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5465: if (version) *version = kctx->version;
5466: if (rtol_0) *rtol_0 = kctx->rtol_0;
5467: if (rtol_max) *rtol_max = kctx->rtol_max;
5468: if (gamma) *gamma = kctx->gamma;
5469: if (alpha) *alpha = kctx->alpha;
5470: if (alpha2) *alpha2 = kctx->alpha2;
5471: if (threshold) *threshold = kctx->threshold;
5472: PetscFunctionReturn(PETSC_SUCCESS);
5473: }
5475: PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5476: {
5477: SNES snes = (SNES)ctx;
5478: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5479: PetscReal rtol = PETSC_CURRENT, stol;
5481: PetscFunctionBegin;
5482: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5483: if (!snes->iter) {
5484: rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5485: PetscCall(VecNorm(snes->vec_func, NORM_2, &kctx->norm_first));
5486: } else {
5487: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1-4 are supported: %" PetscInt_FMT, kctx->version);
5488: if (kctx->version == 1) {
5489: rtol = PetscAbsReal(snes->norm - kctx->lresid_last) / kctx->norm_last;
5490: stol = PetscPowReal(kctx->rtol_last, kctx->alpha2);
5491: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5492: } else if (kctx->version == 2) {
5493: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5494: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5495: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5496: } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5497: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5498: /* safeguard: avoid sharp decrease of rtol */
5499: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5500: stol = PetscMax(rtol, stol);
5501: rtol = PetscMin(kctx->rtol_0, stol);
5502: /* safeguard: avoid oversolving */
5503: stol = kctx->gamma * (kctx->norm_first * snes->rtol) / snes->norm;
5504: stol = PetscMax(rtol, stol);
5505: rtol = PetscMin(kctx->rtol_0, stol);
5506: } else /* if (kctx->version == 4) */ {
5507: /* H.-B. An et al. Journal of Computational and Applied Mathematics 200 (2007) 47-60 */
5508: PetscReal ared = PetscAbsReal(kctx->norm_last - snes->norm);
5509: PetscReal pred = PetscAbsReal(kctx->norm_last - kctx->lresid_last);
5510: PetscReal rk = ared / pred;
5511: if (rk < kctx->v4_p1) rtol = 1. - 2. * kctx->v4_p1;
5512: else if (rk < kctx->v4_p2) rtol = kctx->rtol_last;
5513: else if (rk < kctx->v4_p3) rtol = kctx->v4_m1 * kctx->rtol_last;
5514: else rtol = kctx->v4_m2 * kctx->rtol_last;
5516: 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;
5517: kctx->rtol_last_2 = kctx->rtol_last;
5518: kctx->rk_last_2 = kctx->rk_last;
5519: kctx->rk_last = rk;
5520: }
5521: }
5522: /* safeguard: avoid rtol greater than rtol_max */
5523: rtol = PetscMin(rtol, kctx->rtol_max);
5524: PetscCall(KSPSetTolerances(ksp, rtol, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT));
5525: PetscCall(PetscInfo(snes, "iter %" PetscInt_FMT ", Eisenstat-Walker (version %" PetscInt_FMT ") KSP rtol=%g\n", snes->iter, kctx->version, (double)rtol));
5526: PetscFunctionReturn(PETSC_SUCCESS);
5527: }
5529: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5530: {
5531: SNES snes = (SNES)ctx;
5532: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5533: PCSide pcside;
5534: Vec lres;
5536: PetscFunctionBegin;
5537: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5538: PetscCall(KSPGetTolerances(ksp, &kctx->rtol_last, NULL, NULL, NULL));
5539: kctx->norm_last = snes->norm;
5540: if (kctx->version == 1 || kctx->version == 4) {
5541: PC pc;
5542: PetscBool getRes;
5544: PetscCall(KSPGetPC(ksp, &pc));
5545: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCNONE, &getRes));
5546: if (!getRes) {
5547: KSPNormType normtype;
5549: PetscCall(KSPGetNormType(ksp, &normtype));
5550: getRes = (PetscBool)(normtype == KSP_NORM_UNPRECONDITIONED);
5551: }
5552: PetscCall(KSPGetPCSide(ksp, &pcside));
5553: if (pcside == PC_RIGHT || getRes) { /* KSP residual is true linear residual */
5554: PetscCall(KSPGetResidualNorm(ksp, &kctx->lresid_last));
5555: } else {
5556: /* KSP residual is preconditioned residual */
5557: /* compute true linear residual norm */
5558: Mat J;
5559: PetscCall(KSPGetOperators(ksp, &J, NULL));
5560: PetscCall(VecDuplicate(b, &lres));
5561: PetscCall(MatMult(J, x, lres));
5562: PetscCall(VecAYPX(lres, -1.0, b));
5563: PetscCall(VecNorm(lres, NORM_2, &kctx->lresid_last));
5564: PetscCall(VecDestroy(&lres));
5565: }
5566: }
5567: PetscFunctionReturn(PETSC_SUCCESS);
5568: }
5570: /*@
5571: SNESGetKSP - Returns the `KSP` context for a `SNES` solver.
5573: Not Collective, but if `snes` is parallel, then `ksp` is parallel
5575: Input Parameter:
5576: . snes - the `SNES` context
5578: Output Parameter:
5579: . ksp - the `KSP` context
5581: Level: beginner
5583: Notes:
5584: The user can then directly manipulate the `KSP` context to set various
5585: options, etc. Likewise, the user can then extract and manipulate the
5586: `PC` contexts as well.
5588: Some `SNESType`s do not use a `KSP` but a `KSP` is still returned by this function, changes to that `KSP` will have no effect.
5590: .seealso: [](ch_snes), `SNES`, `KSP`, `PC`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
5591: @*/
5592: PetscErrorCode SNESGetKSP(SNES snes, KSP *ksp)
5593: {
5594: PetscFunctionBegin;
5596: PetscAssertPointer(ksp, 2);
5598: if (!snes->ksp) {
5599: PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes), &snes->ksp));
5600: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->ksp, (PetscObject)snes, 1));
5602: PetscCall(KSPSetPreSolve(snes->ksp, KSPPreSolve_SNESEW, snes));
5603: PetscCall(KSPSetPostSolve(snes->ksp, KSPPostSolve_SNESEW, snes));
5605: PetscCall(KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes));
5606: PetscCall(PetscObjectSetOptions((PetscObject)snes->ksp, ((PetscObject)snes)->options));
5607: }
5608: *ksp = snes->ksp;
5609: PetscFunctionReturn(PETSC_SUCCESS);
5610: }
5612: #include <petsc/private/dmimpl.h>
5613: /*@
5614: SNESSetDM - Sets the `DM` that may be used by some `SNES` nonlinear solvers or their underlying preconditioners
5616: Logically Collective
5618: Input Parameters:
5619: + snes - the nonlinear solver context
5620: - dm - the `DM`, cannot be `NULL`
5622: Level: intermediate
5624: Note:
5625: A `DM` can only be used for solving one problem at a time because information about the problem is stored on the `DM`,
5626: even when not using interfaces like `DMSNESSetFunction()`. Use `DMClone()` to get a distinct `DM` when solving different
5627: problems using the same function space.
5629: .seealso: [](ch_snes), `DM`, `SNES`, `SNESGetDM()`, `KSPSetDM()`, `KSPGetDM()`
5630: @*/
5631: PetscErrorCode SNESSetDM(SNES snes, DM dm)
5632: {
5633: KSP ksp;
5634: DMSNES sdm;
5636: PetscFunctionBegin;
5639: PetscCall(PetscObjectReference((PetscObject)dm));
5640: if (snes->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
5641: if (snes->dm->dmsnes && !dm->dmsnes) {
5642: PetscCall(DMCopyDMSNES(snes->dm, dm));
5643: PetscCall(DMGetDMSNES(snes->dm, &sdm));
5644: if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5645: }
5646: PetscCall(DMCoarsenHookRemove(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
5647: PetscCall(DMDestroy(&snes->dm));
5648: }
5649: snes->dm = dm;
5650: snes->dmAuto = PETSC_FALSE;
5652: PetscCall(SNESGetKSP(snes, &ksp));
5653: PetscCall(KSPSetDM(ksp, dm));
5654: PetscCall(KSPSetDMActive(ksp, PETSC_FALSE));
5655: if (snes->npc) {
5656: PetscCall(SNESSetDM(snes->npc, snes->dm));
5657: PetscCall(SNESSetNPCSide(snes, snes->npcside));
5658: }
5659: PetscFunctionReturn(PETSC_SUCCESS);
5660: }
5662: /*@
5663: SNESGetDM - Gets the `DM` that may be used by some `SNES` nonlinear solvers/preconditioners
5665: Not Collective but `dm` obtained is parallel on `snes`
5667: Input Parameter:
5668: . snes - the `SNES` context
5670: Output Parameter:
5671: . dm - the `DM`
5673: Level: intermediate
5675: .seealso: [](ch_snes), `DM`, `SNES`, `SNESSetDM()`, `KSPSetDM()`, `KSPGetDM()`
5676: @*/
5677: PetscErrorCode SNESGetDM(SNES snes, DM *dm)
5678: {
5679: PetscFunctionBegin;
5681: if (!snes->dm) {
5682: PetscCall(DMShellCreate(PetscObjectComm((PetscObject)snes), &snes->dm));
5683: snes->dmAuto = PETSC_TRUE;
5684: }
5685: *dm = snes->dm;
5686: PetscFunctionReturn(PETSC_SUCCESS);
5687: }
5689: /*@
5690: SNESSetNPC - Sets the nonlinear preconditioner to be used.
5692: Collective
5694: Input Parameters:
5695: + snes - iterative context obtained from `SNESCreate()`
5696: - npc - the `SNES` nonlinear preconditioner object
5698: Options Database Key:
5699: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5701: Level: developer
5703: Notes:
5704: This is rarely used, rather use `SNESGetNPC()` to retrieve the preconditioner and configure it using the API.
5706: Only some `SNESType` can use a nonlinear preconditioner
5708: .seealso: [](ch_snes), `SNES`, `SNESNGS`, `SNESFAS`, `SNESGetNPC()`, `SNESHasNPC()`
5709: @*/
5710: PetscErrorCode SNESSetNPC(SNES snes, SNES npc)
5711: {
5712: PetscFunctionBegin;
5715: PetscCheckSameComm(snes, 1, npc, 2);
5716: PetscCall(PetscObjectReference((PetscObject)npc));
5717: PetscCall(SNESDestroy(&snes->npc));
5718: snes->npc = npc;
5719: PetscFunctionReturn(PETSC_SUCCESS);
5720: }
5722: /*@
5723: SNESGetNPC - Gets a nonlinear preconditioning solver SNES` to be used to precondition the original nonlinear solver.
5725: Not Collective; but any changes to the obtained the `pc` object must be applied collectively
5727: Input Parameter:
5728: . snes - iterative context obtained from `SNESCreate()`
5730: Output Parameter:
5731: . pc - the `SNES` preconditioner context
5733: Options Database Key:
5734: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5736: Level: advanced
5738: Notes:
5739: If a `SNES` was previously set with `SNESSetNPC()` then that value is returned, otherwise a new `SNES` object is created that will
5740: be used as the nonlinear preconditioner for the current `SNES`.
5742: The (preconditioner) `SNES` returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5743: `SNES`. These may be overwritten if needed.
5745: Use the options database prefixes `-npc_snes`, `-npc_ksp`, etc., to control the configuration of the nonlinear preconditioner
5747: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESHasNPC()`, `SNES`, `SNESCreate()`
5748: @*/
5749: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5750: {
5751: const char *optionsprefix;
5753: PetscFunctionBegin;
5755: PetscAssertPointer(pc, 2);
5756: if (!snes->npc) {
5757: void *ctx;
5759: PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &snes->npc));
5760: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->npc, (PetscObject)snes, 1));
5761: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5762: PetscCall(SNESSetOptionsPrefix(snes->npc, optionsprefix));
5763: PetscCall(SNESAppendOptionsPrefix(snes->npc, "npc_"));
5764: if (snes->ops->usercompute) {
5765: PetscCall(SNESSetComputeApplicationContext(snes, snes->ops->usercompute, snes->ops->ctxdestroy));
5766: } else {
5767: PetscCall(SNESGetApplicationContext(snes, &ctx));
5768: PetscCall(SNESSetApplicationContext(snes->npc, ctx));
5769: }
5770: PetscCall(SNESSetCountersReset(snes->npc, PETSC_FALSE));
5771: }
5772: *pc = snes->npc;
5773: PetscFunctionReturn(PETSC_SUCCESS);
5774: }
5776: /*@
5777: SNESHasNPC - Returns whether a nonlinear preconditioner is associated with the given `SNES`
5779: Not Collective
5781: Input Parameter:
5782: . snes - iterative context obtained from `SNESCreate()`
5784: Output Parameter:
5785: . has_npc - whether the `SNES` has a nonlinear preconditioner or not
5787: Level: developer
5789: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESGetNPC()`
5790: @*/
5791: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5792: {
5793: PetscFunctionBegin;
5795: PetscAssertPointer(has_npc, 2);
5796: *has_npc = snes->npc ? PETSC_TRUE : PETSC_FALSE;
5797: PetscFunctionReturn(PETSC_SUCCESS);
5798: }
5800: /*@
5801: SNESSetNPCSide - Sets the nonlinear preconditioning side used by the nonlinear preconditioner inside `SNES`.
5803: Logically Collective
5805: Input Parameter:
5806: . snes - iterative context obtained from `SNESCreate()`
5808: Output Parameter:
5809: . side - the preconditioning side, where side is one of
5810: .vb
5811: PC_LEFT - left preconditioning
5812: PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5813: .ve
5815: Options Database Key:
5816: . -snes_npc_side <right,left> - nonlinear preconditioner side
5818: Level: intermediate
5820: Note:
5821: `SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.
5823: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESNRICHARDSON`, `SNESNCG`, `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5824: @*/
5825: PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
5826: {
5827: PetscFunctionBegin;
5830: if (side == PC_SIDE_DEFAULT) side = PC_RIGHT;
5831: PetscCheck((side == PC_LEFT) || (side == PC_RIGHT), PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Only PC_LEFT and PC_RIGHT are supported");
5832: snes->npcside = side;
5833: PetscFunctionReturn(PETSC_SUCCESS);
5834: }
5836: /*@
5837: SNESGetNPCSide - Gets the preconditioning side used by the nonlinear preconditioner inside `SNES`.
5839: Not Collective
5841: Input Parameter:
5842: . snes - iterative context obtained from `SNESCreate()`
5844: Output Parameter:
5845: . side - the preconditioning side, where side is one of
5846: .vb
5847: `PC_LEFT` - left preconditioning
5848: `PC_RIGHT` - right preconditioning (default for most nonlinear solvers)
5849: .ve
5851: Level: intermediate
5853: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESSetNPCSide()`, `KSPGetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5854: @*/
5855: PetscErrorCode SNESGetNPCSide(SNES snes, PCSide *side)
5856: {
5857: PetscFunctionBegin;
5859: PetscAssertPointer(side, 2);
5860: *side = snes->npcside;
5861: PetscFunctionReturn(PETSC_SUCCESS);
5862: }
5864: /*@
5865: SNESSetLineSearch - Sets the `SNESLineSearch` to be used for a given `SNES`
5867: Collective
5869: Input Parameters:
5870: + snes - iterative context obtained from `SNESCreate()`
5871: - linesearch - the linesearch object
5873: Level: developer
5875: Note:
5876: This is almost never used, rather one uses `SNESGetLineSearch()` to retrieve the line search and set options on it
5877: to configure it using the API).
5879: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`
5880: @*/
5881: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5882: {
5883: PetscFunctionBegin;
5886: PetscCheckSameComm(snes, 1, linesearch, 2);
5887: PetscCall(PetscObjectReference((PetscObject)linesearch));
5888: PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5890: snes->linesearch = linesearch;
5891: PetscFunctionReturn(PETSC_SUCCESS);
5892: }
5894: /*@
5895: SNESGetLineSearch - Returns the line search associated with the `SNES`.
5897: Not Collective
5899: Input Parameter:
5900: . snes - iterative context obtained from `SNESCreate()`
5902: Output Parameter:
5903: . linesearch - linesearch context
5905: Level: beginner
5907: Notes:
5908: It creates a default line search instance which can be configured as needed in case it has not been already set with `SNESSetLineSearch()`.
5910: You can also use the options database keys `-snes_linesearch_*` to configure the line search. See `SNESLineSearchSetFromOptions()` for the possible options.
5912: .seealso: [](ch_snes), `SNESLineSearch`, `SNESSetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`
5913: @*/
5914: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5915: {
5916: const char *optionsprefix;
5918: PetscFunctionBegin;
5920: PetscAssertPointer(linesearch, 2);
5921: if (!snes->linesearch) {
5922: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5923: PetscCall(SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch));
5924: PetscCall(SNESLineSearchSetSNES(snes->linesearch, snes));
5925: PetscCall(SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix));
5926: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->linesearch, (PetscObject)snes, 1));
5927: }
5928: *linesearch = snes->linesearch;
5929: PetscFunctionReturn(PETSC_SUCCESS);
5930: }