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 isascii, 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, &isascii));
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 (isascii) {
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_SINGLE_LIBRARY_INTERN 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: PetscCall(PetscOptionsName("-snes_test_function", "Compare hand-coded and finite difference functions", "None", &snes->testFunc));
1126: PetscCall(PetscOptionsName("-snes_test_jacobian", "Compare hand-coded and finite difference Jacobians", "None", &snes->testJac));
1128: flg = PETSC_FALSE;
1129: PetscCall(SNESGetNPCSide(snes, &pcside));
1130: PetscCall(PetscOptionsEnum("-snes_npc_side", "SNES nonlinear preconditioner side", "SNESSetNPCSide", PCSides, (PetscEnum)pcside, (PetscEnum *)&pcside, &flg));
1131: if (flg) PetscCall(SNESSetNPCSide(snes, pcside));
1133: #if defined(PETSC_HAVE_SAWS)
1134: /*
1135: Publish convergence information using SAWs
1136: */
1137: flg = PETSC_FALSE;
1138: PetscCall(PetscOptionsBool("-snes_monitor_saws", "Publish SNES progress using SAWs", "SNESMonitorSet", flg, &flg, NULL));
1139: if (flg) {
1140: void *ctx;
1141: PetscCall(SNESMonitorSAWsCreate(snes, &ctx));
1142: PetscCall(SNESMonitorSet(snes, SNESMonitorSAWs, ctx, SNESMonitorSAWsDestroy));
1143: }
1144: #endif
1145: #if defined(PETSC_HAVE_SAWS)
1146: {
1147: PetscBool set;
1148: flg = PETSC_FALSE;
1149: PetscCall(PetscOptionsBool("-snes_saws_block", "Block for SAWs at end of SNESSolve", "PetscObjectSAWsBlock", ((PetscObject)snes)->amspublishblock, &flg, &set));
1150: if (set) PetscCall(PetscObjectSAWsSetBlock((PetscObject)snes, flg));
1151: }
1152: #endif
1154: for (i = 0; i < numberofsetfromoptions; i++) PetscCall((*othersetfromoptions[i])(snes));
1156: PetscTryTypeMethod(snes, setfromoptions, PetscOptionsObject);
1158: /* process any options handlers added with PetscObjectAddOptionsHandler() */
1159: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)snes, PetscOptionsObject));
1160: PetscOptionsEnd();
1162: if (snes->linesearch) {
1163: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
1164: PetscCall(SNESLineSearchSetFromOptions(snes->linesearch));
1165: }
1167: if (snes->usesksp) {
1168: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
1169: PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre));
1170: PetscCall(KSPSetFromOptions(snes->ksp));
1171: }
1173: /* if user has set the SNES NPC type via options database, create it. */
1174: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1175: PetscCall(PetscOptionsHasName(((PetscObject)snes)->options, optionsprefix, "-npc_snes_type", &pcset));
1176: if (pcset && (!snes->npc)) PetscCall(SNESGetNPC(snes, &snes->npc));
1177: if (snes->npc) PetscCall(SNESSetFromOptions(snes->npc));
1178: snes->setfromoptionscalled++;
1179: PetscFunctionReturn(PETSC_SUCCESS);
1180: }
1182: /*@
1183: SNESResetFromOptions - Sets various `SNES` and `KSP` parameters from user options ONLY if the `SNESSetFromOptions()` was previously called
1185: Collective
1187: Input Parameter:
1188: . snes - the `SNES` context
1190: Level: advanced
1192: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESSetOptionsPrefix()`
1193: @*/
1194: PetscErrorCode SNESResetFromOptions(SNES snes)
1195: {
1196: PetscFunctionBegin;
1197: if (snes->setfromoptionscalled) PetscCall(SNESSetFromOptions(snes));
1198: PetscFunctionReturn(PETSC_SUCCESS);
1199: }
1201: /*@C
1202: SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1203: the nonlinear solvers.
1205: Logically Collective; No Fortran Support
1207: Input Parameters:
1208: + snes - the `SNES` context
1209: . compute - function to compute the context
1210: - destroy - function to destroy the context, see `PetscCtxDestroyFn` for the calling sequence
1212: Calling sequence of `compute`:
1213: + snes - the `SNES` context
1214: - ctx - context to be computed
1216: Level: intermediate
1218: Note:
1219: This routine is useful if you are performing grid sequencing or using `SNESFAS` and need the appropriate context generated for each level.
1221: Use `SNESSetApplicationContext()` to see the context immediately
1223: .seealso: [](ch_snes), `SNESGetApplicationContext()`, `SNESSetApplicationContext()`, `PetscCtxDestroyFn`
1224: @*/
1225: PetscErrorCode SNESSetComputeApplicationContext(SNES snes, PetscErrorCode (*compute)(SNES snes, void **ctx), PetscCtxDestroyFn *destroy)
1226: {
1227: PetscFunctionBegin;
1229: snes->ops->usercompute = compute;
1230: snes->ops->ctxdestroy = destroy;
1231: PetscFunctionReturn(PETSC_SUCCESS);
1232: }
1234: /*@
1235: SNESSetApplicationContext - Sets the optional user-defined context for the nonlinear solvers.
1237: Logically Collective
1239: Input Parameters:
1240: + snes - the `SNES` context
1241: - ctx - the user context
1243: Level: intermediate
1245: Notes:
1246: Users can provide a context when constructing the `SNES` options and then access it inside their function, Jacobian computation, or other evaluation function
1247: with `SNESGetApplicationContext()`
1249: To provide a function that computes the context for you use `SNESSetComputeApplicationContext()`
1251: Fortran Note:
1252: This only works when `ctx` is a Fortran derived type (it cannot be a `PetscObject`), we recommend writing a Fortran interface definition for this
1253: function that tells the Fortran compiler the derived data type that is passed in as the `ctx` argument. See `SNESGetApplicationContext()` for
1254: an example.
1256: .seealso: [](ch_snes), `SNES`, `SNESSetComputeApplicationContext()`, `SNESGetApplicationContext()`
1257: @*/
1258: PetscErrorCode SNESSetApplicationContext(SNES snes, void *ctx)
1259: {
1260: KSP ksp;
1262: PetscFunctionBegin;
1264: PetscCall(SNESGetKSP(snes, &ksp));
1265: PetscCall(KSPSetApplicationContext(ksp, ctx));
1266: snes->ctx = ctx;
1267: PetscFunctionReturn(PETSC_SUCCESS);
1268: }
1270: /*@
1271: SNESGetApplicationContext - Gets the user-defined context for the
1272: nonlinear solvers set with `SNESGetApplicationContext()` or `SNESSetComputeApplicationContext()`
1274: Not Collective
1276: Input Parameter:
1277: . snes - `SNES` context
1279: Output Parameter:
1280: . ctx - user context
1282: Level: intermediate
1284: Fortran Notes:
1285: 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
1286: function that tells the Fortran compiler the derived data type that is returned as the `ctx` argument. For example,
1287: .vb
1288: Interface SNESGetApplicationContext
1289: Subroutine SNESGetApplicationContext(snes,ctx,ierr)
1290: #include <petsc/finclude/petscsnes.h>
1291: use petscsnes
1292: SNES snes
1293: type(tUsertype), pointer :: ctx
1294: PetscErrorCode ierr
1295: End Subroutine
1296: End Interface SNESGetApplicationContext
1297: .ve
1299: The prototype for `ctx` must be
1300: .vb
1301: type(tUsertype), pointer :: ctx
1302: .ve
1304: .seealso: [](ch_snes), `SNESSetApplicationContext()`, `SNESSetComputeApplicationContext()`
1305: @*/
1306: PetscErrorCode SNESGetApplicationContext(SNES snes, PeCtx ctx)
1307: {
1308: PetscFunctionBegin;
1310: *(void **)ctx = snes->ctx;
1311: PetscFunctionReturn(PETSC_SUCCESS);
1312: }
1314: /*@
1315: SNESSetUseMatrixFree - indicates that `SNES` should use matrix-free finite difference matrix-vector products to apply the Jacobian.
1317: Logically Collective
1319: Input Parameters:
1320: + snes - `SNES` context
1321: . mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1322: - 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
1323: this option no matrix-element based preconditioners can be used in the linear solve since the matrix won't be explicitly available
1325: Options Database Keys:
1326: + -snes_mf_operator - use matrix-free only for the mat operator
1327: . -snes_mf - use matrix-free for both the mat and pmat operator
1328: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1329: - -snes_fd - compute the Jacobian via finite differences (slow)
1331: Level: intermediate
1333: Note:
1334: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
1335: and computing explicitly with
1336: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
1338: .seealso: [](ch_snes), `SNES`, `SNESGetUseMatrixFree()`, `MatCreateSNESMF()`, `SNESComputeJacobianDefaultColor()`, `MatFDColoring`
1339: @*/
1340: PetscErrorCode SNESSetUseMatrixFree(SNES snes, PetscBool mf_operator, PetscBool mf)
1341: {
1342: PetscFunctionBegin;
1346: snes->mf = mf_operator ? PETSC_TRUE : mf;
1347: snes->mf_operator = mf_operator;
1348: PetscFunctionReturn(PETSC_SUCCESS);
1349: }
1351: /*@
1352: SNESGetUseMatrixFree - indicates if the `SNES` uses matrix-free finite difference matrix vector products to apply the Jacobian.
1354: Not Collective, but the resulting flags will be the same on all MPI processes
1356: Input Parameter:
1357: . snes - `SNES` context
1359: Output Parameters:
1360: + mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1361: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored
1363: Level: intermediate
1365: .seealso: [](ch_snes), `SNES`, `SNESSetUseMatrixFree()`, `MatCreateSNESMF()`
1366: @*/
1367: PetscErrorCode SNESGetUseMatrixFree(SNES snes, PetscBool *mf_operator, PetscBool *mf)
1368: {
1369: PetscFunctionBegin;
1371: if (mf) *mf = snes->mf;
1372: if (mf_operator) *mf_operator = snes->mf_operator;
1373: PetscFunctionReturn(PETSC_SUCCESS);
1374: }
1376: /*@
1377: SNESGetIterationNumber - Gets the number of nonlinear iterations completed in the current or most recent `SNESSolve()`
1379: Not Collective
1381: Input Parameter:
1382: . snes - `SNES` context
1384: Output Parameter:
1385: . iter - iteration number
1387: Level: intermediate
1389: Notes:
1390: For example, during the computation of iteration 2 this would return 1.
1392: This is useful for using lagged Jacobians (where one does not recompute the
1393: Jacobian at each `SNES` iteration). For example, the code
1394: .vb
1395: ierr = SNESGetIterationNumber(snes,&it);
1396: if (!(it % 2)) {
1397: [compute Jacobian here]
1398: }
1399: .ve
1400: can be used in your function that computes the Jacobian to cause the Jacobian to be
1401: recomputed every second `SNES` iteration. See also `SNESSetLagJacobian()`
1403: After the `SNES` solve is complete this will return the number of nonlinear iterations used.
1405: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetLagJacobian()`, `SNESGetLinearSolveIterations()`, `SNESSetMonitor()`
1406: @*/
1407: PetscErrorCode SNESGetIterationNumber(SNES snes, PetscInt *iter)
1408: {
1409: PetscFunctionBegin;
1411: PetscAssertPointer(iter, 2);
1412: *iter = snes->iter;
1413: PetscFunctionReturn(PETSC_SUCCESS);
1414: }
1416: /*@
1417: SNESSetIterationNumber - Sets the current iteration number.
1419: Not Collective
1421: Input Parameters:
1422: + snes - `SNES` context
1423: - iter - iteration number
1425: Level: developer
1427: Note:
1428: This should only be called inside a `SNES` nonlinear solver.
1430: .seealso: [](ch_snes), `SNESGetLinearSolveIterations()`
1431: @*/
1432: PetscErrorCode SNESSetIterationNumber(SNES snes, PetscInt iter)
1433: {
1434: PetscFunctionBegin;
1436: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
1437: snes->iter = iter;
1438: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
1439: PetscFunctionReturn(PETSC_SUCCESS);
1440: }
1442: /*@
1443: SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1444: attempted by the nonlinear solver in the current or most recent `SNESSolve()` .
1446: Not Collective
1448: Input Parameter:
1449: . snes - `SNES` context
1451: Output Parameter:
1452: . nfails - number of unsuccessful steps attempted
1454: Level: intermediate
1456: Note:
1457: This counter is reset to zero for each successive call to `SNESSolve()`.
1459: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1460: `SNESSetMaxNonlinearStepFailures()`, `SNESGetMaxNonlinearStepFailures()`
1461: @*/
1462: PetscErrorCode SNESGetNonlinearStepFailures(SNES snes, PetscInt *nfails)
1463: {
1464: PetscFunctionBegin;
1466: PetscAssertPointer(nfails, 2);
1467: *nfails = snes->numFailures;
1468: PetscFunctionReturn(PETSC_SUCCESS);
1469: }
1471: /*@
1472: SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1473: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1475: Not Collective
1477: Input Parameters:
1478: + snes - `SNES` context
1479: - maxFails - maximum of unsuccessful steps allowed, use `PETSC_UNLIMITED` to have no limit on the number of failures
1481: Options Database Key:
1482: . -snes_max_fail <n> - maximum number of unsuccessful steps allowed
1484: Level: intermediate
1486: Developer Note:
1487: The options database key is wrong for this function name
1489: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1490: `SNESGetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1491: @*/
1492: PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1493: {
1494: PetscFunctionBegin;
1497: if (maxFails == PETSC_UNLIMITED) {
1498: snes->maxFailures = PETSC_INT_MAX;
1499: } else {
1500: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1501: snes->maxFailures = maxFails;
1502: }
1503: PetscFunctionReturn(PETSC_SUCCESS);
1504: }
1506: /*@
1507: SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1508: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1510: Not Collective
1512: Input Parameter:
1513: . snes - `SNES` context
1515: Output Parameter:
1516: . maxFails - maximum of unsuccessful steps
1518: Level: intermediate
1520: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1521: `SNESSetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1522: @*/
1523: PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1524: {
1525: PetscFunctionBegin;
1527: PetscAssertPointer(maxFails, 2);
1528: *maxFails = snes->maxFailures;
1529: PetscFunctionReturn(PETSC_SUCCESS);
1530: }
1532: /*@
1533: SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1534: done by the `SNES` object in the current or most recent `SNESSolve()`
1536: Not Collective
1538: Input Parameter:
1539: . snes - `SNES` context
1541: Output Parameter:
1542: . nfuncs - number of evaluations
1544: Level: intermediate
1546: Note:
1547: Reset every time `SNESSolve()` is called unless `SNESSetCountersReset()` is used.
1549: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`, `SNESSetCountersReset()`
1550: @*/
1551: PetscErrorCode SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1552: {
1553: PetscFunctionBegin;
1555: PetscAssertPointer(nfuncs, 2);
1556: *nfuncs = snes->nfuncs;
1557: PetscFunctionReturn(PETSC_SUCCESS);
1558: }
1560: /*@
1561: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1562: linear solvers in the current or most recent `SNESSolve()`
1564: Not Collective
1566: Input Parameter:
1567: . snes - `SNES` context
1569: Output Parameter:
1570: . nfails - number of failed solves
1572: Options Database Key:
1573: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1575: Level: intermediate
1577: Note:
1578: This counter is reset to zero for each successive call to `SNESSolve()`.
1580: .seealso: [](ch_snes), `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1581: @*/
1582: PetscErrorCode SNESGetLinearSolveFailures(SNES snes, PetscInt *nfails)
1583: {
1584: PetscFunctionBegin;
1586: PetscAssertPointer(nfails, 2);
1587: *nfails = snes->numLinearSolveFailures;
1588: PetscFunctionReturn(PETSC_SUCCESS);
1589: }
1591: /*@
1592: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1593: allowed before `SNES` returns with a diverged reason of `SNES_DIVERGED_LINEAR_SOLVE`
1595: Logically Collective
1597: Input Parameters:
1598: + snes - `SNES` context
1599: - maxFails - maximum allowed linear solve failures, use `PETSC_UNLIMITED` to have no limit on the number of failures
1601: Options Database Key:
1602: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1604: Level: intermediate
1606: Note:
1607: By default this is 0; that is `SNES` returns on the first failed linear solve
1609: Developer Note:
1610: The options database key is wrong for this function name
1612: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`
1613: @*/
1614: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1615: {
1616: PetscFunctionBegin;
1620: if (maxFails == PETSC_UNLIMITED) {
1621: snes->maxLinearSolveFailures = PETSC_INT_MAX;
1622: } else {
1623: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1624: snes->maxLinearSolveFailures = maxFails;
1625: }
1626: PetscFunctionReturn(PETSC_SUCCESS);
1627: }
1629: /*@
1630: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1631: are allowed before `SNES` returns as unsuccessful
1633: Not Collective
1635: Input Parameter:
1636: . snes - `SNES` context
1638: Output Parameter:
1639: . maxFails - maximum of unsuccessful solves allowed
1641: Level: intermediate
1643: Note:
1644: By default this is 1; that is `SNES` returns on the first failed linear solve
1646: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`,
1647: @*/
1648: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1649: {
1650: PetscFunctionBegin;
1652: PetscAssertPointer(maxFails, 2);
1653: *maxFails = snes->maxLinearSolveFailures;
1654: PetscFunctionReturn(PETSC_SUCCESS);
1655: }
1657: /*@
1658: SNESGetLinearSolveIterations - Gets the total number of linear iterations
1659: used by the nonlinear solver in the most recent `SNESSolve()`
1661: Not Collective
1663: Input Parameter:
1664: . snes - `SNES` context
1666: Output Parameter:
1667: . lits - number of linear iterations
1669: Level: intermediate
1671: Notes:
1672: This counter is reset to zero for each successive call to `SNESSolve()` unless `SNESSetCountersReset()` is used.
1674: 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
1675: then call `KSPGetIterationNumber()` after the failed solve.
1677: .seealso: [](ch_snes), `SNES`, `SNESGetIterationNumber()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESSetCountersReset()`
1678: @*/
1679: PetscErrorCode SNESGetLinearSolveIterations(SNES snes, PetscInt *lits)
1680: {
1681: PetscFunctionBegin;
1683: PetscAssertPointer(lits, 2);
1684: *lits = snes->linear_its;
1685: PetscFunctionReturn(PETSC_SUCCESS);
1686: }
1688: /*@
1689: SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1690: are reset every time `SNESSolve()` is called.
1692: Logically Collective
1694: Input Parameters:
1695: + snes - `SNES` context
1696: - reset - whether to reset the counters or not, defaults to `PETSC_TRUE`
1698: Level: developer
1700: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1701: @*/
1702: PetscErrorCode SNESSetCountersReset(SNES snes, PetscBool reset)
1703: {
1704: PetscFunctionBegin;
1707: snes->counters_reset = reset;
1708: PetscFunctionReturn(PETSC_SUCCESS);
1709: }
1711: /*@
1712: SNESResetCounters - Reset counters for linear iterations and function evaluations.
1714: Logically Collective
1716: Input Parameters:
1717: . snes - `SNES` context
1719: Level: developer
1721: Note:
1722: It honors the flag set with `SNESSetCountersReset()`
1724: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1725: @*/
1726: PetscErrorCode SNESResetCounters(SNES snes)
1727: {
1728: PetscFunctionBegin;
1730: if (snes->counters_reset) {
1731: snes->nfuncs = 0;
1732: snes->linear_its = 0;
1733: snes->numFailures = 0;
1734: }
1735: PetscFunctionReturn(PETSC_SUCCESS);
1736: }
1738: /*@
1739: SNESSetKSP - Sets a `KSP` context for the `SNES` object to use
1741: Not Collective, but the `SNES` and `KSP` objects must live on the same `MPI_Comm`
1743: Input Parameters:
1744: + snes - the `SNES` context
1745: - ksp - the `KSP` context
1747: Level: developer
1749: Notes:
1750: The `SNES` object already has its `KSP` object, you can obtain with `SNESGetKSP()`
1751: so this routine is rarely needed.
1753: The `KSP` object that is already in the `SNES` object has its reference count
1754: decreased by one when this is called.
1756: .seealso: [](ch_snes), `SNES`, `KSP`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`
1757: @*/
1758: PetscErrorCode SNESSetKSP(SNES snes, KSP ksp)
1759: {
1760: PetscFunctionBegin;
1763: PetscCheckSameComm(snes, 1, ksp, 2);
1764: PetscCall(PetscObjectReference((PetscObject)ksp));
1765: if (snes->ksp) PetscCall(PetscObjectDereference((PetscObject)snes->ksp));
1766: snes->ksp = ksp;
1767: PetscFunctionReturn(PETSC_SUCCESS);
1768: }
1770: /*@
1771: SNESParametersInitialize - Sets all the parameters in `snes` to their default value (when `SNESCreate()` was called) if they
1772: currently contain default values
1774: Collective
1776: Input Parameter:
1777: . snes - the `SNES` object
1779: Level: developer
1781: Developer Note:
1782: This is called by all the `SNESCreate_XXX()` routines.
1784: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`,
1785: `PetscObjectParameterSetDefault()`
1786: @*/
1787: PetscErrorCode SNESParametersInitialize(SNES snes)
1788: {
1789: PetscObjectParameterSetDefault(snes, max_its, 50);
1790: PetscObjectParameterSetDefault(snes, max_funcs, 10000);
1791: PetscObjectParameterSetDefault(snes, rtol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1792: PetscObjectParameterSetDefault(snes, abstol, PetscDefined(USE_REAL_SINGLE) ? 1.e-25 : 1.e-50);
1793: PetscObjectParameterSetDefault(snes, stol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1794: PetscObjectParameterSetDefault(snes, divtol, 1.e4);
1795: return PETSC_SUCCESS;
1796: }
1798: /*@
1799: SNESCreate - Creates a nonlinear solver context used to manage a set of nonlinear solves
1801: Collective
1803: Input Parameter:
1804: . comm - MPI communicator
1806: Output Parameter:
1807: . outsnes - the new `SNES` context
1809: Options Database Keys:
1810: + -snes_mf - Activates default matrix-free Jacobian-vector products, and no matrix to construct a preconditioner
1811: . -snes_mf_operator - Activates default matrix-free Jacobian-vector products, and a user-provided matrix as set by `SNESSetJacobian()`
1812: . -snes_fd_coloring - uses a relative fast computation of the Jacobian using finite differences and a graph coloring
1813: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
1815: Level: beginner
1817: Developer Notes:
1818: `SNES` always creates a `KSP` object even though many `SNES` methods do not use it. This is
1819: unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1820: particular method does use `KSP` and regulates if the information about the `KSP` is printed
1821: in `SNESView()`.
1823: `TSSetFromOptions()` does call `SNESSetFromOptions()` which can lead to users being confused
1824: by help messages about meaningless `SNES` options.
1826: `SNES` always creates the `snes->kspconvctx` even though it is used by only one type. This should be fixed.
1828: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
1829: @*/
1830: PetscErrorCode SNESCreate(MPI_Comm comm, SNES *outsnes)
1831: {
1832: SNES snes;
1833: SNESKSPEW *kctx;
1835: PetscFunctionBegin;
1836: PetscAssertPointer(outsnes, 2);
1837: PetscCall(SNESInitializePackage());
1839: PetscCall(PetscHeaderCreate(snes, SNES_CLASSID, "SNES", "Nonlinear solver", "SNES", comm, SNESDestroy, SNESView));
1840: snes->ops->converged = SNESConvergedDefault;
1841: snes->usesksp = PETSC_TRUE;
1842: snes->norm = 0.0;
1843: snes->xnorm = 0.0;
1844: snes->ynorm = 0.0;
1845: snes->normschedule = SNES_NORM_ALWAYS;
1846: snes->functype = SNES_FUNCTION_DEFAULT;
1847: snes->ttol = 0.0;
1849: snes->rnorm0 = 0;
1850: snes->nfuncs = 0;
1851: snes->numFailures = 0;
1852: snes->maxFailures = 1;
1853: snes->linear_its = 0;
1854: snes->lagjacobian = 1;
1855: snes->jac_iter = 0;
1856: snes->lagjac_persist = PETSC_FALSE;
1857: snes->lagpreconditioner = 1;
1858: snes->pre_iter = 0;
1859: snes->lagpre_persist = PETSC_FALSE;
1860: snes->numbermonitors = 0;
1861: snes->numberreasonviews = 0;
1862: snes->data = NULL;
1863: snes->setupcalled = PETSC_FALSE;
1864: snes->ksp_ewconv = PETSC_FALSE;
1865: snes->nwork = 0;
1866: snes->work = NULL;
1867: snes->nvwork = 0;
1868: snes->vwork = NULL;
1869: snes->conv_hist_len = 0;
1870: snes->conv_hist_max = 0;
1871: snes->conv_hist = NULL;
1872: snes->conv_hist_its = NULL;
1873: snes->conv_hist_reset = PETSC_TRUE;
1874: snes->counters_reset = PETSC_TRUE;
1875: snes->vec_func_init_set = PETSC_FALSE;
1876: snes->reason = SNES_CONVERGED_ITERATING;
1877: snes->npcside = PC_RIGHT;
1878: snes->setfromoptionscalled = 0;
1880: snes->mf = PETSC_FALSE;
1881: snes->mf_operator = PETSC_FALSE;
1882: snes->mf_version = 1;
1884: snes->numLinearSolveFailures = 0;
1885: snes->maxLinearSolveFailures = 1;
1887: snes->vizerotolerance = 1.e-8;
1888: snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;
1890: /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1891: snes->alwayscomputesfinalresidual = PETSC_FALSE;
1893: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1894: PetscCall(PetscNew(&kctx));
1896: snes->kspconvctx = kctx;
1897: kctx->version = 2;
1898: kctx->rtol_0 = 0.3; /* Eisenstat and Walker suggest rtol_0=.5, but
1899: this was too large for some test cases */
1900: kctx->rtol_last = 0.0;
1901: kctx->rtol_max = 0.9;
1902: kctx->gamma = 1.0;
1903: kctx->alpha = 0.5 * (1.0 + PetscSqrtReal(5.0));
1904: kctx->alpha2 = kctx->alpha;
1905: kctx->threshold = 0.1;
1906: kctx->lresid_last = 0.0;
1907: kctx->norm_last = 0.0;
1909: kctx->rk_last = 0.0;
1910: kctx->rk_last_2 = 0.0;
1911: kctx->rtol_last_2 = 0.0;
1912: kctx->v4_p1 = 0.1;
1913: kctx->v4_p2 = 0.4;
1914: kctx->v4_p3 = 0.7;
1915: kctx->v4_m1 = 0.8;
1916: kctx->v4_m2 = 0.5;
1917: kctx->v4_m3 = 0.1;
1918: kctx->v4_m4 = 0.5;
1920: PetscCall(SNESParametersInitialize(snes));
1921: *outsnes = snes;
1922: PetscFunctionReturn(PETSC_SUCCESS);
1923: }
1925: /*@C
1926: SNESSetFunction - Sets the function evaluation routine and function
1927: vector for use by the `SNES` routines in solving systems of nonlinear
1928: equations.
1930: Logically Collective
1932: Input Parameters:
1933: + snes - the `SNES` context
1934: . r - vector to store function values, may be `NULL`
1935: . f - function evaluation routine; for calling sequence see `SNESFunctionFn`
1936: - ctx - [optional] user-defined context for private data for the
1937: function evaluation routine (may be `NULL`)
1939: Level: beginner
1941: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetPicard()`, `SNESFunctionFn`
1942: @*/
1943: PetscErrorCode SNESSetFunction(SNES snes, Vec r, SNESFunctionFn *f, void *ctx)
1944: {
1945: DM dm;
1947: PetscFunctionBegin;
1949: if (r) {
1951: PetscCheckSameComm(snes, 1, r, 2);
1952: PetscCall(PetscObjectReference((PetscObject)r));
1953: PetscCall(VecDestroy(&snes->vec_func));
1954: snes->vec_func = r;
1955: }
1956: PetscCall(SNESGetDM(snes, &dm));
1957: PetscCall(DMSNESSetFunction(dm, f, ctx));
1958: if (f == SNESPicardComputeFunction) PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
1959: PetscFunctionReturn(PETSC_SUCCESS);
1960: }
1962: /*@C
1963: SNESSetInitialFunction - Set an already computed function evaluation at the initial guess to be reused by `SNESSolve()`.
1965: Logically Collective
1967: Input Parameters:
1968: + snes - the `SNES` context
1969: - f - vector to store function value
1971: Level: developer
1973: Notes:
1974: This should not be modified during the solution procedure.
1976: This is used extensively in the `SNESFAS` hierarchy and in nonlinear preconditioning.
1978: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetInitialFunctionNorm()`
1979: @*/
1980: PetscErrorCode SNESSetInitialFunction(SNES snes, Vec f)
1981: {
1982: Vec vec_func;
1984: PetscFunctionBegin;
1987: PetscCheckSameComm(snes, 1, f, 2);
1988: if (snes->npcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1989: snes->vec_func_init_set = PETSC_FALSE;
1990: PetscFunctionReturn(PETSC_SUCCESS);
1991: }
1992: PetscCall(SNESGetFunction(snes, &vec_func, NULL, NULL));
1993: PetscCall(VecCopy(f, vec_func));
1995: snes->vec_func_init_set = PETSC_TRUE;
1996: PetscFunctionReturn(PETSC_SUCCESS);
1997: }
1999: /*@
2000: SNESSetNormSchedule - Sets the `SNESNormSchedule` used in convergence and monitoring
2001: of the `SNES` method, when norms are computed in the solving process
2003: Logically Collective
2005: Input Parameters:
2006: + snes - the `SNES` context
2007: - normschedule - the frequency of norm computation
2009: Options Database Key:
2010: . -snes_norm_schedule <none, always, initialonly, finalonly, initialfinalonly> - set the schedule
2012: Level: advanced
2014: Notes:
2015: Only certain `SNES` methods support certain `SNESNormSchedules`. Most require evaluation
2016: of the nonlinear function and the taking of its norm at every iteration to
2017: even ensure convergence at all. However, methods such as custom Gauss-Seidel methods
2018: `SNESNGS` and the like do not require the norm of the function to be computed, and therefore
2019: may either be monitored for convergence or not. As these are often used as nonlinear
2020: preconditioners, monitoring the norm of their error is not a useful enterprise within
2021: their solution.
2023: .seealso: [](ch_snes), `SNESNormSchedule`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`
2024: @*/
2025: PetscErrorCode SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
2026: {
2027: PetscFunctionBegin;
2029: snes->normschedule = normschedule;
2030: PetscFunctionReturn(PETSC_SUCCESS);
2031: }
2033: /*@
2034: SNESGetNormSchedule - Gets the `SNESNormSchedule` used in convergence and monitoring
2035: of the `SNES` method.
2037: Logically Collective
2039: Input Parameters:
2040: + snes - the `SNES` context
2041: - normschedule - the type of the norm used
2043: Level: advanced
2045: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2046: @*/
2047: PetscErrorCode SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
2048: {
2049: PetscFunctionBegin;
2051: *normschedule = snes->normschedule;
2052: PetscFunctionReturn(PETSC_SUCCESS);
2053: }
2055: /*@
2056: SNESSetFunctionNorm - Sets the last computed residual norm.
2058: Logically Collective
2060: Input Parameters:
2061: + snes - the `SNES` context
2062: - norm - the value of the norm
2064: Level: developer
2066: .seealso: [](ch_snes), `SNES`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2067: @*/
2068: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
2069: {
2070: PetscFunctionBegin;
2072: snes->norm = norm;
2073: PetscFunctionReturn(PETSC_SUCCESS);
2074: }
2076: /*@
2077: SNESGetFunctionNorm - Gets the last computed norm of the residual
2079: Not Collective
2081: Input Parameter:
2082: . snes - the `SNES` context
2084: Output Parameter:
2085: . norm - the last computed residual norm
2087: Level: developer
2089: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2090: @*/
2091: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
2092: {
2093: PetscFunctionBegin;
2095: PetscAssertPointer(norm, 2);
2096: *norm = snes->norm;
2097: PetscFunctionReturn(PETSC_SUCCESS);
2098: }
2100: /*@
2101: SNESGetUpdateNorm - Gets the last computed norm of the solution update
2103: Not Collective
2105: Input Parameter:
2106: . snes - the `SNES` context
2108: Output Parameter:
2109: . ynorm - the last computed update norm
2111: Level: developer
2113: Note:
2114: The new solution is the current solution plus the update, so this norm is an indication of the size of the update
2116: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`
2117: @*/
2118: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2119: {
2120: PetscFunctionBegin;
2122: PetscAssertPointer(ynorm, 2);
2123: *ynorm = snes->ynorm;
2124: PetscFunctionReturn(PETSC_SUCCESS);
2125: }
2127: /*@
2128: SNESGetSolutionNorm - Gets the last computed norm of the solution
2130: Not Collective
2132: Input Parameter:
2133: . snes - the `SNES` context
2135: Output Parameter:
2136: . xnorm - the last computed solution norm
2138: Level: developer
2140: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`, `SNESGetUpdateNorm()`
2141: @*/
2142: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2143: {
2144: PetscFunctionBegin;
2146: PetscAssertPointer(xnorm, 2);
2147: *xnorm = snes->xnorm;
2148: PetscFunctionReturn(PETSC_SUCCESS);
2149: }
2151: /*@
2152: SNESSetFunctionType - Sets the `SNESFunctionType`
2153: of the `SNES` method.
2155: Logically Collective
2157: Input Parameters:
2158: + snes - the `SNES` context
2159: - type - the function type
2161: Level: developer
2163: Values of the function type\:
2164: + `SNES_FUNCTION_DEFAULT` - the default for the given `SNESType`
2165: . `SNES_FUNCTION_UNPRECONDITIONED` - an unpreconditioned function evaluation (this is the function provided with `SNESSetFunction()`
2166: - `SNES_FUNCTION_PRECONDITIONED` - a transformation of the function provided with `SNESSetFunction()`
2168: Note:
2169: Different `SNESType`s use this value in different ways
2171: .seealso: [](ch_snes), `SNES`, `SNESFunctionType`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2172: @*/
2173: PetscErrorCode SNESSetFunctionType(SNES snes, SNESFunctionType type)
2174: {
2175: PetscFunctionBegin;
2177: snes->functype = type;
2178: PetscFunctionReturn(PETSC_SUCCESS);
2179: }
2181: /*@
2182: SNESGetFunctionType - Gets the `SNESFunctionType` used in convergence and monitoring set with `SNESSetFunctionType()`
2183: of the SNES method.
2185: Logically Collective
2187: Input Parameters:
2188: + snes - the `SNES` context
2189: - type - the type of the function evaluation, see `SNESSetFunctionType()`
2191: Level: advanced
2193: .seealso: [](ch_snes), `SNESSetFunctionType()`, `SNESFunctionType`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2194: @*/
2195: PetscErrorCode SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2196: {
2197: PetscFunctionBegin;
2199: *type = snes->functype;
2200: PetscFunctionReturn(PETSC_SUCCESS);
2201: }
2203: /*@C
2204: SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2205: use with composed nonlinear solvers.
2207: Input Parameters:
2208: + snes - the `SNES` context, usually of the `SNESType` `SNESNGS`
2209: . f - function evaluation routine to apply Gauss-Seidel, see `SNESNGSFn` for calling sequence
2210: - ctx - [optional] user-defined context for private data for the smoother evaluation routine (may be `NULL`)
2212: Level: intermediate
2214: Note:
2215: The `SNESNGS` routines are used by the composed nonlinear solver to generate
2216: a problem appropriate update to the solution, particularly `SNESFAS`.
2218: .seealso: [](ch_snes), `SNESNGS`, `SNESGetNGS()`, `SNESNCG`, `SNESGetFunction()`, `SNESComputeNGS()`, `SNESNGSFn`
2219: @*/
2220: PetscErrorCode SNESSetNGS(SNES snes, SNESNGSFn *f, void *ctx)
2221: {
2222: DM dm;
2224: PetscFunctionBegin;
2226: PetscCall(SNESGetDM(snes, &dm));
2227: PetscCall(DMSNESSetNGS(dm, f, ctx));
2228: PetscFunctionReturn(PETSC_SUCCESS);
2229: }
2231: /*
2232: This is used for -snes_mf_operator; it uses a duplicate of snes->jacobian_pre because snes->jacobian_pre cannot be
2233: changed during the KSPSolve()
2234: */
2235: PetscErrorCode SNESPicardComputeMFFunction(SNES snes, Vec x, Vec f, void *ctx)
2236: {
2237: DM dm;
2238: DMSNES sdm;
2240: PetscFunctionBegin;
2241: PetscCall(SNESGetDM(snes, &dm));
2242: PetscCall(DMGetDMSNES(dm, &sdm));
2243: /* A(x)*x - b(x) */
2244: if (sdm->ops->computepfunction) {
2245: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2246: PetscCall(VecScale(f, -1.0));
2247: /* Cannot share nonzero pattern because of the possible use of SNESComputeJacobianDefault() */
2248: if (!snes->picard) PetscCall(MatDuplicate(snes->jacobian_pre, MAT_DO_NOT_COPY_VALUES, &snes->picard));
2249: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2250: PetscCall(MatMultAdd(snes->picard, x, f, f));
2251: } else {
2252: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2253: PetscCall(MatMult(snes->picard, x, f));
2254: }
2255: PetscFunctionReturn(PETSC_SUCCESS);
2256: }
2258: PetscErrorCode SNESPicardComputeFunction(SNES snes, Vec x, Vec f, void *ctx)
2259: {
2260: DM dm;
2261: DMSNES sdm;
2263: PetscFunctionBegin;
2264: PetscCall(SNESGetDM(snes, &dm));
2265: PetscCall(DMGetDMSNES(dm, &sdm));
2266: /* A(x)*x - b(x) */
2267: if (sdm->ops->computepfunction) {
2268: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2269: PetscCall(VecScale(f, -1.0));
2270: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2271: PetscCall(MatMultAdd(snes->jacobian_pre, x, f, f));
2272: } else {
2273: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2274: PetscCall(MatMult(snes->jacobian_pre, x, f));
2275: }
2276: PetscFunctionReturn(PETSC_SUCCESS);
2277: }
2279: PetscErrorCode SNESPicardComputeJacobian(SNES snes, Vec x1, Mat J, Mat B, void *ctx)
2280: {
2281: PetscFunctionBegin;
2282: /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2283: /* must assembly if matrix-free to get the last SNES solution */
2284: PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
2285: PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
2286: PetscFunctionReturn(PETSC_SUCCESS);
2287: }
2289: /*@C
2290: SNESSetPicard - Use `SNES` to solve the system $A(x) x = bp(x) + b $ via a Picard type iteration (Picard linearization)
2292: Logically Collective
2294: Input Parameters:
2295: + snes - the `SNES` context
2296: . r - vector to store function values, may be `NULL`
2297: . bp - function evaluation routine, may be `NULL`, for the calling sequence see `SNESFunctionFn`
2298: . Amat - matrix with which $A(x) x - bp(x) - b$ is to be computed
2299: . Pmat - matrix from which preconditioner is computed (usually the same as `Amat`)
2300: . J - function to compute matrix values, for the calling sequence see `SNESJacobianFn`
2301: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
2303: Level: intermediate
2305: Notes:
2306: It is often better to provide the nonlinear function $F()$ and some approximation to its Jacobian directly and use
2307: 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.
2309: One can call `SNESSetPicard()` or `SNESSetFunction()` (and possibly `SNESSetJacobian()`) but cannot call both
2311: Solves the equation $A(x) x = bp(x) - b$ via the defect correction algorithm $A(x^{n}) (x^{n+1} - x^{n}) = bp(x^{n}) + b - A(x^{n})x^{n}$.
2312: When an exact solver is used this corresponds to the "classic" Picard $A(x^{n}) x^{n+1} = bp(x^{n}) + b$ iteration.
2314: Run with `-snes_mf_operator` to solve the system with Newton's method using $A(x^{n})$ to construct the preconditioner.
2316: We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2317: the direct Picard iteration $A(x^n) x^{n+1} = bp(x^n) + b$
2319: 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
2320: 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
2321: different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument \:-).
2323: 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
2324: $A(x^{n})$ is used to build the preconditioner
2326: When used with `-snes_fd` this will compute the true Jacobian (very slowly one column at a time) and thus represent Newton's method.
2328: 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
2329: 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
2330: 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`.
2331: See the comment in src/snes/tutorials/ex15.c.
2333: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESGetPicard()`, `SNESLineSearchPreCheckPicard()`,
2334: `SNESFunctionFn`, `SNESJacobianFn`
2335: @*/
2336: PetscErrorCode SNESSetPicard(SNES snes, Vec r, SNESFunctionFn *bp, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
2337: {
2338: DM dm;
2340: PetscFunctionBegin;
2342: PetscCall(SNESGetDM(snes, &dm));
2343: PetscCall(DMSNESSetPicard(dm, bp, J, ctx));
2344: PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2345: PetscCall(SNESSetFunction(snes, r, SNESPicardComputeFunction, ctx));
2346: PetscCall(SNESSetJacobian(snes, Amat, Pmat, SNESPicardComputeJacobian, ctx));
2347: PetscFunctionReturn(PETSC_SUCCESS);
2348: }
2350: /*@C
2351: SNESGetPicard - Returns the context for the Picard iteration
2353: Not Collective, but `Vec` is parallel if `SNES` is parallel. Collective if `Vec` is requested, but has not been created yet.
2355: Input Parameter:
2356: . snes - the `SNES` context
2358: Output Parameters:
2359: + r - the function (or `NULL`)
2360: . f - the function (or `NULL`); for calling sequence see `SNESFunctionFn`
2361: . Amat - the matrix used to defined the operation A(x) x - b(x) (or `NULL`)
2362: . Pmat - the matrix from which the preconditioner will be constructed (or `NULL`)
2363: . J - the function for matrix evaluation (or `NULL`); for calling sequence see `SNESJacobianFn`
2364: - ctx - the function context (or `NULL`)
2366: Level: advanced
2368: .seealso: [](ch_snes), `SNESSetFunction()`, `SNESSetPicard()`, `SNESGetFunction()`, `SNESGetJacobian()`, `SNESGetDM()`, `SNESFunctionFn`, `SNESJacobianFn`
2369: @*/
2370: PetscErrorCode SNESGetPicard(SNES snes, Vec *r, SNESFunctionFn **f, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
2371: {
2372: DM dm;
2374: PetscFunctionBegin;
2376: PetscCall(SNESGetFunction(snes, r, NULL, NULL));
2377: PetscCall(SNESGetJacobian(snes, Amat, Pmat, NULL, NULL));
2378: PetscCall(SNESGetDM(snes, &dm));
2379: PetscCall(DMSNESGetPicard(dm, f, J, ctx));
2380: PetscFunctionReturn(PETSC_SUCCESS);
2381: }
2383: /*@C
2384: SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the nonlinear problem
2386: Logically Collective
2388: Input Parameters:
2389: + snes - the `SNES` context
2390: . func - function evaluation routine, see `SNESInitialGuessFn` for the calling sequence
2391: - ctx - [optional] user-defined context for private data for the
2392: function evaluation routine (may be `NULL`)
2394: Level: intermediate
2396: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESInitialGuessFn`
2397: @*/
2398: PetscErrorCode SNESSetComputeInitialGuess(SNES snes, SNESInitialGuessFn *func, void *ctx)
2399: {
2400: PetscFunctionBegin;
2402: if (func) snes->ops->computeinitialguess = func;
2403: if (ctx) snes->initialguessP = ctx;
2404: PetscFunctionReturn(PETSC_SUCCESS);
2405: }
2407: /*@C
2408: SNESGetRhs - Gets the vector for solving F(x) = `rhs`. If `rhs` is not set
2409: it assumes a zero right-hand side.
2411: Logically Collective
2413: Input Parameter:
2414: . snes - the `SNES` context
2416: Output Parameter:
2417: . rhs - the right-hand side vector or `NULL` if there is no right-hand side vector
2419: Level: intermediate
2421: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetFunction()`
2422: @*/
2423: PetscErrorCode SNESGetRhs(SNES snes, Vec *rhs)
2424: {
2425: PetscFunctionBegin;
2427: PetscAssertPointer(rhs, 2);
2428: *rhs = snes->vec_rhs;
2429: PetscFunctionReturn(PETSC_SUCCESS);
2430: }
2432: /*@
2433: SNESComputeFunction - Calls the function that has been set with `SNESSetFunction()`.
2435: Collective
2437: Input Parameters:
2438: + snes - the `SNES` context
2439: - x - input vector
2441: Output Parameter:
2442: . y - function vector, as set by `SNESSetFunction()`
2444: Level: developer
2446: Notes:
2447: `SNESComputeFunction()` is typically used within nonlinear solvers
2448: implementations, so users would not generally call this routine themselves.
2450: When solving for $F(x) = b$, this routine computes $y = F(x) - b$.
2452: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeMFFunction()`
2453: @*/
2454: PetscErrorCode SNESComputeFunction(SNES snes, Vec x, Vec y)
2455: {
2456: DM dm;
2457: DMSNES sdm;
2459: PetscFunctionBegin;
2463: PetscCheckSameComm(snes, 1, x, 2);
2464: PetscCheckSameComm(snes, 1, y, 3);
2465: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2467: PetscCall(SNESGetDM(snes, &dm));
2468: PetscCall(DMGetDMSNES(dm, &sdm));
2469: 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().");
2470: if (sdm->ops->computefunction) {
2471: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2472: PetscCall(VecLockReadPush(x));
2473: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2474: snes->domainerror = PETSC_FALSE;
2475: {
2476: void *ctx;
2477: SNESFunctionFn *computefunction;
2478: PetscCall(DMSNESGetFunction(dm, &computefunction, &ctx));
2479: PetscCallBack("SNES callback function", (*computefunction)(snes, x, y, ctx));
2480: }
2481: PetscCall(VecLockReadPop(x));
2482: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2483: } else /* if (snes->vec_rhs) */ {
2484: PetscCall(MatMult(snes->jacobian, x, y));
2485: }
2486: if (snes->vec_rhs) PetscCall(VecAXPY(y, -1.0, snes->vec_rhs));
2487: snes->nfuncs++;
2488: /*
2489: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2490: propagate the value to all processes
2491: */
2492: PetscCall(VecFlag(y, snes->domainerror));
2493: PetscFunctionReturn(PETSC_SUCCESS);
2494: }
2496: /*@
2497: SNESComputeMFFunction - Calls the function that has been set with `DMSNESSetMFFunction()`.
2499: Collective
2501: Input Parameters:
2502: + snes - the `SNES` context
2503: - x - input vector
2505: Output Parameter:
2506: . y - output vector
2508: Level: developer
2510: Notes:
2511: `SNESComputeMFFunction()` is used within the matrix-vector products called by the matrix created with `MatCreateSNESMF()`
2512: so users would not generally call this routine themselves.
2514: Since this function is intended for use with finite differencing it does not subtract the right-hand side vector provided with `SNESSolve()`
2515: while `SNESComputeFunction()` does. As such, this routine cannot be used with `MatMFFDSetBase()` with a provided F function value even if it applies the
2516: 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.
2518: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `MatCreateSNESMF()`, `DMSNESSetMFFunction()`
2519: @*/
2520: PetscErrorCode SNESComputeMFFunction(SNES snes, Vec x, Vec y)
2521: {
2522: DM dm;
2523: DMSNES sdm;
2525: PetscFunctionBegin;
2529: PetscCheckSameComm(snes, 1, x, 2);
2530: PetscCheckSameComm(snes, 1, y, 3);
2531: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2533: PetscCall(SNESGetDM(snes, &dm));
2534: PetscCall(DMGetDMSNES(dm, &sdm));
2535: PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2536: PetscCall(VecLockReadPush(x));
2537: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2538: snes->domainerror = PETSC_FALSE;
2539: PetscCallBack("SNES callback function", (*sdm->ops->computemffunction)(snes, x, y, sdm->mffunctionctx));
2540: PetscCall(VecLockReadPop(x));
2541: PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2542: snes->nfuncs++;
2543: /*
2544: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2545: propagate the value to all processes
2546: */
2547: PetscCall(VecFlag(y, snes->domainerror));
2548: PetscFunctionReturn(PETSC_SUCCESS);
2549: }
2551: /*@
2552: SNESComputeNGS - Calls the Gauss-Seidel function that has been set with `SNESSetNGS()`.
2554: Collective
2556: Input Parameters:
2557: + snes - the `SNES` context
2558: . x - input vector
2559: - b - rhs vector
2561: Output Parameter:
2562: . x - new solution vector
2564: Level: developer
2566: Note:
2567: `SNESComputeNGS()` is typically used within composed nonlinear solver
2568: implementations, so most users would not generally call this routine
2569: themselves.
2571: .seealso: [](ch_snes), `SNESNGSFn`, `SNESSetNGS()`, `SNESComputeFunction()`, `SNESNGS`
2572: @*/
2573: PetscErrorCode SNESComputeNGS(SNES snes, Vec b, Vec x)
2574: {
2575: DM dm;
2576: DMSNES sdm;
2578: PetscFunctionBegin;
2582: PetscCheckSameComm(snes, 1, x, 3);
2583: if (b) PetscCheckSameComm(snes, 1, b, 2);
2584: if (b) PetscCall(VecValidValues_Internal(b, 2, PETSC_TRUE));
2585: PetscCall(PetscLogEventBegin(SNES_NGSEval, snes, x, b, 0));
2586: PetscCall(SNESGetDM(snes, &dm));
2587: PetscCall(DMGetDMSNES(dm, &sdm));
2588: PetscCheck(sdm->ops->computegs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2589: if (b) PetscCall(VecLockReadPush(b));
2590: PetscCallBack("SNES callback NGS", (*sdm->ops->computegs)(snes, x, b, sdm->gsctx));
2591: if (b) PetscCall(VecLockReadPop(b));
2592: PetscCall(PetscLogEventEnd(SNES_NGSEval, snes, x, b, 0));
2593: PetscFunctionReturn(PETSC_SUCCESS);
2594: }
2596: static PetscErrorCode SNESComputeFunction_FD(SNES snes, Vec Xin, Vec G)
2597: {
2598: Vec X;
2599: PetscScalar *g;
2600: PetscReal f, f2;
2601: PetscInt low, high, N, i;
2602: PetscBool flg;
2603: PetscReal h = .5 * PETSC_SQRT_MACHINE_EPSILON;
2605: PetscFunctionBegin;
2606: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_fd_delta", &h, &flg));
2607: PetscCall(VecDuplicate(Xin, &X));
2608: PetscCall(VecCopy(Xin, X));
2609: PetscCall(VecGetSize(X, &N));
2610: PetscCall(VecGetOwnershipRange(X, &low, &high));
2611: PetscCall(VecSetOption(X, VEC_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE));
2612: PetscCall(VecGetArray(G, &g));
2613: for (i = 0; i < N; i++) {
2614: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2615: PetscCall(VecAssemblyBegin(X));
2616: PetscCall(VecAssemblyEnd(X));
2617: PetscCall(SNESComputeObjective(snes, X, &f));
2618: PetscCall(VecSetValue(X, i, 2.0 * h, ADD_VALUES));
2619: PetscCall(VecAssemblyBegin(X));
2620: PetscCall(VecAssemblyEnd(X));
2621: PetscCall(SNESComputeObjective(snes, X, &f2));
2622: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2623: PetscCall(VecAssemblyBegin(X));
2624: PetscCall(VecAssemblyEnd(X));
2625: if (i >= low && i < high) g[i - low] = (f2 - f) / (2.0 * h);
2626: }
2627: PetscCall(VecRestoreArray(G, &g));
2628: PetscCall(VecDestroy(&X));
2629: PetscFunctionReturn(PETSC_SUCCESS);
2630: }
2632: /*@
2633: SNESTestFunction - Computes the difference between the computed and finite-difference functions
2635: Collective
2637: Input Parameter:
2638: . snes - the `SNES` context
2640: Options Database Keys:
2641: + -snes_test_function - compare the user provided function with one compute via finite differences to check for errors.
2642: - -snes_test_function_view - display the user provided function, the finite difference function and the difference
2644: Level: developer
2646: .seealso: [](ch_snes), `SNESTestJacobian()`, `SNESSetFunction()`, `SNESComputeFunction()`
2647: @*/
2648: PetscErrorCode SNESTestFunction(SNES snes)
2649: {
2650: Vec x, g1, g2, g3;
2651: PetscBool complete_print = PETSC_FALSE;
2652: PetscReal hcnorm, fdnorm, hcmax, fdmax, diffmax, diffnorm;
2653: PetscScalar dot;
2654: MPI_Comm comm;
2655: PetscViewer viewer, mviewer;
2656: PetscViewerFormat format;
2657: PetscInt tabs;
2658: static PetscBool directionsprinted = PETSC_FALSE;
2659: SNESObjectiveFn *objective;
2661: PetscFunctionBegin;
2662: PetscCall(SNESGetObjective(snes, &objective, NULL));
2663: if (!objective) PetscFunctionReturn(PETSC_SUCCESS);
2665: PetscObjectOptionsBegin((PetscObject)snes);
2666: PetscCall(PetscOptionsViewer("-snes_test_function_view", "View difference between hand-coded and finite difference function element entries", "None", &mviewer, &format, &complete_print));
2667: PetscOptionsEnd();
2669: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2670: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2671: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2672: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2673: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Function -------------\n"));
2674: if (!complete_print && !directionsprinted) {
2675: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_function_view and optionally -snes_test_function <threshold> to show difference\n"));
2676: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference function entries greater than <threshold>.\n"));
2677: }
2678: if (!directionsprinted) {
2679: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Function, if (for double precision runs) ||F - Ffd||/||F|| is\n"));
2680: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Function is probably correct.\n"));
2681: directionsprinted = PETSC_TRUE;
2682: }
2683: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2685: PetscCall(SNESGetSolution(snes, &x));
2686: PetscCall(VecDuplicate(x, &g1));
2687: PetscCall(VecDuplicate(x, &g2));
2688: PetscCall(VecDuplicate(x, &g3));
2689: PetscCall(SNESComputeFunction(snes, x, g1));
2690: PetscCall(SNESComputeFunction_FD(snes, x, g2));
2692: PetscCall(VecNorm(g2, NORM_2, &fdnorm));
2693: PetscCall(VecNorm(g1, NORM_2, &hcnorm));
2694: PetscCall(VecNorm(g2, NORM_INFINITY, &fdmax));
2695: PetscCall(VecNorm(g1, NORM_INFINITY, &hcmax));
2696: PetscCall(VecDot(g1, g2, &dot));
2697: PetscCall(VecCopy(g1, g3));
2698: PetscCall(VecAXPY(g3, -1.0, g2));
2699: PetscCall(VecNorm(g3, NORM_2, &diffnorm));
2700: PetscCall(VecNorm(g3, NORM_INFINITY, &diffmax));
2701: PetscCall(PetscViewerASCIIPrintf(viewer, " ||Ffd|| %g, ||F|| = %g, angle cosine = (Ffd'F)/||Ffd||||F|| = %g\n", (double)fdnorm, (double)hcnorm, (double)(PetscRealPart(dot) / (fdnorm * hcnorm))));
2702: PetscCall(PetscViewerASCIIPrintf(viewer, " 2-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffnorm / PetscMax(hcnorm, fdnorm)), (double)diffnorm));
2703: PetscCall(PetscViewerASCIIPrintf(viewer, " max-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffmax / PetscMax(hcmax, fdmax)), (double)diffmax));
2705: if (complete_print) {
2706: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded function ----------\n"));
2707: PetscCall(VecView(g1, mviewer));
2708: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference function ----------\n"));
2709: PetscCall(VecView(g2, mviewer));
2710: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference function ----------\n"));
2711: PetscCall(VecView(g3, mviewer));
2712: }
2713: PetscCall(VecDestroy(&g1));
2714: PetscCall(VecDestroy(&g2));
2715: PetscCall(VecDestroy(&g3));
2717: if (complete_print) {
2718: PetscCall(PetscViewerPopFormat(mviewer));
2719: PetscCall(PetscViewerDestroy(&mviewer));
2720: }
2721: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2722: PetscFunctionReturn(PETSC_SUCCESS);
2723: }
2725: /*@
2726: SNESTestJacobian - Computes the difference between the computed and finite-difference Jacobians
2728: Collective
2730: Input Parameter:
2731: . snes - the `SNES` context
2733: Output Parameters:
2734: + Jnorm - the Frobenius norm of the computed Jacobian, or `NULL`
2735: - diffNorm - the Frobenius norm of the difference of the computed and finite-difference Jacobians, or `NULL`
2737: Options Database Keys:
2738: + -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.
2739: - -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference
2741: Level: developer
2743: Note:
2744: Directions and norms are printed to stdout if `diffNorm` is `NULL`.
2746: .seealso: [](ch_snes), `SNESTestFunction()`, `SNESSetJacobian()`, `SNESComputeJacobian()`
2747: @*/
2748: PetscErrorCode SNESTestJacobian(SNES snes, PetscReal *Jnorm, PetscReal *diffNorm)
2749: {
2750: Mat A, B, C, D, jacobian;
2751: Vec x = snes->vec_sol, f;
2752: PetscReal nrm, gnorm;
2753: PetscReal threshold = 1.e-5;
2754: MatType mattype;
2755: PetscInt m, n, M, N;
2756: void *functx;
2757: PetscBool complete_print = PETSC_FALSE, threshold_print = PETSC_FALSE, flg, istranspose;
2758: PetscBool silent = diffNorm != PETSC_NULLPTR ? PETSC_TRUE : PETSC_FALSE;
2759: PetscViewer viewer, mviewer;
2760: MPI_Comm comm;
2761: PetscInt tabs;
2762: static PetscBool directionsprinted = PETSC_FALSE;
2763: PetscViewerFormat format;
2765: PetscFunctionBegin;
2766: PetscObjectOptionsBegin((PetscObject)snes);
2767: PetscCall(PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold, NULL));
2768: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display", "-snes_test_jacobian_view", "3.13", NULL));
2769: PetscCall(PetscOptionsViewer("-snes_test_jacobian_view", "View difference between hand-coded and finite difference Jacobians element entries", "None", &mviewer, &format, &complete_print));
2770: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display_threshold", "-snes_test_jacobian", "3.13", "-snes_test_jacobian accepts an optional threshold (since v3.10)"));
2771: 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));
2772: PetscOptionsEnd();
2774: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2775: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2776: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2777: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2778: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian -------------\n"));
2779: if (!complete_print && !silent && !directionsprinted) {
2780: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n"));
2781: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference Jacobian entries greater than <threshold>.\n"));
2782: }
2783: if (!directionsprinted && !silent) {
2784: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n"));
2785: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Jacobian is probably correct.\n"));
2786: directionsprinted = PETSC_TRUE;
2787: }
2788: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2790: PetscCall(PetscObjectTypeCompare((PetscObject)snes->jacobian, MATMFFD, &flg));
2791: if (!flg) jacobian = snes->jacobian;
2792: else jacobian = snes->jacobian_pre;
2794: if (!x) PetscCall(MatCreateVecs(jacobian, &x, NULL));
2795: else PetscCall(PetscObjectReference((PetscObject)x));
2796: PetscCall(VecDuplicate(x, &f));
2798: /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2799: PetscCall(SNESComputeFunction(snes, x, f));
2800: PetscCall(VecDestroy(&f));
2801: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESKSPTRANSPOSEONLY, &istranspose));
2802: while (jacobian) {
2803: Mat JT = NULL, Jsave = NULL;
2805: if (istranspose) {
2806: PetscCall(MatCreateTranspose(jacobian, &JT));
2807: Jsave = jacobian;
2808: jacobian = JT;
2809: }
2810: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)jacobian, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
2811: if (flg) {
2812: A = jacobian;
2813: PetscCall(PetscObjectReference((PetscObject)A));
2814: } else {
2815: PetscCall(MatComputeOperator(jacobian, MATAIJ, &A));
2816: }
2818: PetscCall(MatGetType(A, &mattype));
2819: PetscCall(MatGetSize(A, &M, &N));
2820: PetscCall(MatGetLocalSize(A, &m, &n));
2821: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &B));
2822: PetscCall(MatSetType(B, mattype));
2823: PetscCall(MatSetSizes(B, m, n, M, N));
2824: PetscCall(MatSetBlockSizesFromMats(B, A, A));
2825: PetscCall(MatSetUp(B));
2826: PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2828: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
2829: PetscCall(SNESComputeJacobianDefault(snes, x, B, B, functx));
2831: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &D));
2832: PetscCall(MatAYPX(D, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2833: PetscCall(MatNorm(D, NORM_FROBENIUS, &nrm));
2834: PetscCall(MatNorm(A, NORM_FROBENIUS, &gnorm));
2835: PetscCall(MatDestroy(&D));
2836: if (!gnorm) gnorm = 1; /* just in case */
2837: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n", (double)(nrm / gnorm), (double)nrm));
2838: if (complete_print) {
2839: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded Jacobian ----------\n"));
2840: PetscCall(MatView(A, mviewer));
2841: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference Jacobian ----------\n"));
2842: PetscCall(MatView(B, mviewer));
2843: }
2845: if (threshold_print || complete_print) {
2846: PetscInt Istart, Iend, *ccols, bncols, cncols, j, row;
2847: PetscScalar *cvals;
2848: const PetscInt *bcols;
2849: const PetscScalar *bvals;
2851: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2852: PetscCall(MatSetType(C, mattype));
2853: PetscCall(MatSetSizes(C, m, n, M, N));
2854: PetscCall(MatSetBlockSizesFromMats(C, A, A));
2855: PetscCall(MatSetUp(C));
2856: PetscCall(MatSetOption(C, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2858: PetscCall(MatAYPX(B, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2859: PetscCall(MatGetOwnershipRange(B, &Istart, &Iend));
2861: for (row = Istart; row < Iend; row++) {
2862: PetscCall(MatGetRow(B, row, &bncols, &bcols, &bvals));
2863: PetscCall(PetscMalloc2(bncols, &ccols, bncols, &cvals));
2864: for (j = 0, cncols = 0; j < bncols; j++) {
2865: if (PetscAbsScalar(bvals[j]) > threshold) {
2866: ccols[cncols] = bcols[j];
2867: cvals[cncols] = bvals[j];
2868: cncols += 1;
2869: }
2870: }
2871: if (cncols) PetscCall(MatSetValues(C, 1, &row, cncols, ccols, cvals, INSERT_VALUES));
2872: PetscCall(MatRestoreRow(B, row, &bncols, &bcols, &bvals));
2873: PetscCall(PetscFree2(ccols, cvals));
2874: }
2875: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2876: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2877: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n", (double)threshold));
2878: PetscCall(MatView(C, complete_print ? mviewer : viewer));
2879: PetscCall(MatDestroy(&C));
2880: }
2881: PetscCall(MatDestroy(&A));
2882: PetscCall(MatDestroy(&B));
2883: PetscCall(MatDestroy(&JT));
2884: if (Jsave) jacobian = Jsave;
2885: if (jacobian != snes->jacobian_pre) {
2886: jacobian = snes->jacobian_pre;
2887: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian for preconditioner -------------\n"));
2888: } else jacobian = NULL;
2889: }
2890: PetscCall(VecDestroy(&x));
2891: if (complete_print) PetscCall(PetscViewerPopFormat(mviewer));
2892: if (mviewer) PetscCall(PetscViewerDestroy(&mviewer));
2893: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2895: if (Jnorm) *Jnorm = gnorm;
2896: if (diffNorm) *diffNorm = nrm;
2897: PetscFunctionReturn(PETSC_SUCCESS);
2898: }
2900: /*@
2901: SNESComputeJacobian - Computes the Jacobian matrix that has been set with `SNESSetJacobian()`.
2903: Collective
2905: Input Parameters:
2906: + snes - the `SNES` context
2907: - X - input vector
2909: Output Parameters:
2910: + A - Jacobian matrix
2911: - B - optional matrix for building the preconditioner, usually the same as `A`
2913: Options Database Keys:
2914: + -snes_lag_preconditioner <lag> - how often to rebuild preconditioner
2915: . -snes_lag_jacobian <lag> - how often to rebuild Jacobian
2916: . -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.
2917: . -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
2918: . -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2919: . -snes_compare_explicit_draw - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2920: . -snes_compare_explicit_contour - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2921: . -snes_compare_operator - Make the comparison options above use the operator instead of the matrix used to construct the preconditioner
2922: . -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2923: . -snes_compare_coloring_display - Compute the finite difference Jacobian using coloring and display verbose differences
2924: . -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2925: . -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2926: . -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2927: . -snes_compare_coloring_draw - Compute the finite difference Jacobian using coloring and draw differences
2928: - -snes_compare_coloring_draw_contour - Compute the finite difference Jacobian using coloring and show contours of matrices and differences
2930: Level: developer
2932: Note:
2933: Most users should not need to explicitly call this routine, as it
2934: is used internally within the nonlinear solvers.
2936: Developer Note:
2937: 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
2938: with the `SNESType` of test that has been removed.
2940: .seealso: [](ch_snes), `SNESSetJacobian()`, `KSPSetOperators()`, `MatStructure`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
2941: @*/
2942: PetscErrorCode SNESComputeJacobian(SNES snes, Vec X, Mat A, Mat B)
2943: {
2944: PetscBool flag;
2945: DM dm;
2946: DMSNES sdm;
2947: KSP ksp;
2949: PetscFunctionBegin;
2952: PetscCheckSameComm(snes, 1, X, 2);
2953: PetscCall(VecValidValues_Internal(X, 2, PETSC_TRUE));
2954: PetscCall(SNESGetDM(snes, &dm));
2955: PetscCall(DMGetDMSNES(dm, &sdm));
2957: /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix-free */
2958: if (snes->lagjacobian == -2) {
2959: snes->lagjacobian = -1;
2961: PetscCall(PetscInfo(snes, "Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n"));
2962: } else if (snes->lagjacobian == -1) {
2963: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is -1\n"));
2964: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2965: if (flag) {
2966: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2967: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2968: }
2969: PetscFunctionReturn(PETSC_SUCCESS);
2970: } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2971: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagjacobian, snes->iter));
2972: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2973: if (flag) {
2974: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2975: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2976: }
2977: PetscFunctionReturn(PETSC_SUCCESS);
2978: }
2979: if (snes->npc && snes->npcside == PC_LEFT) {
2980: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2981: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2982: PetscFunctionReturn(PETSC_SUCCESS);
2983: }
2985: PetscCall(PetscLogEventBegin(SNES_JacobianEval, snes, X, A, B));
2986: PetscCall(VecLockReadPush(X));
2987: {
2988: void *ctx;
2989: SNESJacobianFn *J;
2990: PetscCall(DMSNESGetJacobian(dm, &J, &ctx));
2991: PetscCallBack("SNES callback Jacobian", (*J)(snes, X, A, B, ctx));
2992: }
2993: PetscCall(VecLockReadPop(X));
2994: PetscCall(PetscLogEventEnd(SNES_JacobianEval, snes, X, A, B));
2996: /* attach latest linearization point to the matrix used to construct the preconditioner */
2997: PetscCall(PetscObjectCompose((PetscObject)B, "__SNES_latest_X", (PetscObject)X));
2999: /* the next line ensures that snes->ksp exists */
3000: PetscCall(SNESGetKSP(snes, &ksp));
3001: if (snes->lagpreconditioner == -2) {
3002: PetscCall(PetscInfo(snes, "Rebuilding preconditioner exactly once since lag is -2\n"));
3003: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
3004: snes->lagpreconditioner = -1;
3005: } else if (snes->lagpreconditioner == -1) {
3006: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is -1\n"));
3007: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
3008: } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
3009: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagpreconditioner, snes->iter));
3010: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
3011: } else {
3012: PetscCall(PetscInfo(snes, "Rebuilding preconditioner\n"));
3013: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
3014: }
3016: /* monkey business to allow testing Jacobians in multilevel solvers.
3017: This is needed because the SNESTestXXX interface does not accept vectors and matrices */
3018: {
3019: Vec xsave = snes->vec_sol;
3020: Mat jacobiansave = snes->jacobian;
3021: Mat jacobian_presave = snes->jacobian_pre;
3023: snes->vec_sol = X;
3024: snes->jacobian = A;
3025: snes->jacobian_pre = B;
3026: if (snes->testFunc) PetscCall(SNESTestFunction(snes));
3027: if (snes->testJac) PetscCall(SNESTestJacobian(snes, NULL, NULL));
3029: snes->vec_sol = xsave;
3030: snes->jacobian = jacobiansave;
3031: snes->jacobian_pre = jacobian_presave;
3032: }
3034: {
3035: PetscBool flag = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_operator = PETSC_FALSE;
3036: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit", NULL, NULL, &flag));
3037: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw", NULL, NULL, &flag_draw));
3038: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw_contour", NULL, NULL, &flag_contour));
3039: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_operator", NULL, NULL, &flag_operator));
3040: if (flag || flag_draw || flag_contour) {
3041: Mat Bexp_mine = NULL, Bexp, FDexp;
3042: PetscViewer vdraw, vstdout;
3043: PetscBool flg;
3044: if (flag_operator) {
3045: PetscCall(MatComputeOperator(A, MATAIJ, &Bexp_mine));
3046: Bexp = Bexp_mine;
3047: } else {
3048: /* See if the matrix used to construct the preconditioner can be viewed and added directly */
3049: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)B, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPIBAIJ, ""));
3050: if (flg) Bexp = B;
3051: else {
3052: /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
3053: PetscCall(MatComputeOperator(B, MATAIJ, &Bexp_mine));
3054: Bexp = Bexp_mine;
3055: }
3056: }
3057: PetscCall(MatConvert(Bexp, MATSAME, MAT_INITIAL_MATRIX, &FDexp));
3058: PetscCall(SNESComputeJacobianDefault(snes, X, FDexp, FDexp, NULL));
3059: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3060: if (flag_draw || flag_contour) {
3061: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Explicit Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3062: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3063: } else vdraw = NULL;
3064: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit %s\n", flag_operator ? "Jacobian" : "preconditioning Jacobian"));
3065: if (flag) PetscCall(MatView(Bexp, vstdout));
3066: if (vdraw) PetscCall(MatView(Bexp, vdraw));
3067: PetscCall(PetscViewerASCIIPrintf(vstdout, "Finite difference Jacobian\n"));
3068: if (flag) PetscCall(MatView(FDexp, vstdout));
3069: if (vdraw) PetscCall(MatView(FDexp, vdraw));
3070: PetscCall(MatAYPX(FDexp, -1.0, Bexp, SAME_NONZERO_PATTERN));
3071: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian\n"));
3072: if (flag) PetscCall(MatView(FDexp, vstdout));
3073: if (vdraw) { /* Always use contour for the difference */
3074: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3075: PetscCall(MatView(FDexp, vdraw));
3076: PetscCall(PetscViewerPopFormat(vdraw));
3077: }
3078: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3079: PetscCall(PetscViewerDestroy(&vdraw));
3080: PetscCall(MatDestroy(&Bexp_mine));
3081: PetscCall(MatDestroy(&FDexp));
3082: }
3083: }
3084: {
3085: PetscBool flag = PETSC_FALSE, flag_display = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_threshold = PETSC_FALSE;
3086: PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON, threshold_rtol = 10 * PETSC_SQRT_MACHINE_EPSILON;
3087: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring", NULL, NULL, &flag));
3088: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_display", NULL, NULL, &flag_display));
3089: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw", NULL, NULL, &flag_draw));
3090: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw_contour", NULL, NULL, &flag_contour));
3091: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold", NULL, NULL, &flag_threshold));
3092: if (flag_threshold) {
3093: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_rtol", &threshold_rtol, NULL));
3094: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_atol", &threshold_atol, NULL));
3095: }
3096: if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
3097: Mat Bfd;
3098: PetscViewer vdraw, vstdout;
3099: MatColoring coloring;
3100: ISColoring iscoloring;
3101: MatFDColoring matfdcoloring;
3102: SNESFunctionFn *func;
3103: void *funcctx;
3104: PetscReal norm1, norm2, normmax;
3106: PetscCall(MatDuplicate(B, MAT_DO_NOT_COPY_VALUES, &Bfd));
3107: PetscCall(MatColoringCreate(Bfd, &coloring));
3108: PetscCall(MatColoringSetType(coloring, MATCOLORINGSL));
3109: PetscCall(MatColoringSetFromOptions(coloring));
3110: PetscCall(MatColoringApply(coloring, &iscoloring));
3111: PetscCall(MatColoringDestroy(&coloring));
3112: PetscCall(MatFDColoringCreate(Bfd, iscoloring, &matfdcoloring));
3113: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3114: PetscCall(MatFDColoringSetUp(Bfd, iscoloring, matfdcoloring));
3115: PetscCall(ISColoringDestroy(&iscoloring));
3117: /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
3118: PetscCall(SNESGetFunction(snes, NULL, &func, &funcctx));
3119: PetscCall(MatFDColoringSetFunction(matfdcoloring, (MatFDColoringFn *)func, funcctx));
3120: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring, ((PetscObject)snes)->prefix));
3121: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring, "coloring_"));
3122: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3123: PetscCall(MatFDColoringApply(Bfd, matfdcoloring, X, snes));
3124: PetscCall(MatFDColoringDestroy(&matfdcoloring));
3126: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3127: if (flag_draw || flag_contour) {
3128: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Colored Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3129: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3130: } else vdraw = NULL;
3131: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit preconditioning Jacobian\n"));
3132: if (flag_display) PetscCall(MatView(B, vstdout));
3133: if (vdraw) PetscCall(MatView(B, vdraw));
3134: PetscCall(PetscViewerASCIIPrintf(vstdout, "Colored Finite difference Jacobian\n"));
3135: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3136: if (vdraw) PetscCall(MatView(Bfd, vdraw));
3137: PetscCall(MatAYPX(Bfd, -1.0, B, SAME_NONZERO_PATTERN));
3138: PetscCall(MatNorm(Bfd, NORM_1, &norm1));
3139: PetscCall(MatNorm(Bfd, NORM_FROBENIUS, &norm2));
3140: PetscCall(MatNorm(Bfd, NORM_MAX, &normmax));
3141: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n", (double)norm1, (double)norm2, (double)normmax));
3142: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3143: if (vdraw) { /* Always use contour for the difference */
3144: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3145: PetscCall(MatView(Bfd, vdraw));
3146: PetscCall(PetscViewerPopFormat(vdraw));
3147: }
3148: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3150: if (flag_threshold) {
3151: PetscInt bs, rstart, rend, i;
3152: PetscCall(MatGetBlockSize(B, &bs));
3153: PetscCall(MatGetOwnershipRange(B, &rstart, &rend));
3154: for (i = rstart; i < rend; i++) {
3155: const PetscScalar *ba, *ca;
3156: const PetscInt *bj, *cj;
3157: PetscInt bn, cn, j, maxentrycol = -1, maxdiffcol = -1, maxrdiffcol = -1;
3158: PetscReal maxentry = 0, maxdiff = 0, maxrdiff = 0;
3159: PetscCall(MatGetRow(B, i, &bn, &bj, &ba));
3160: PetscCall(MatGetRow(Bfd, i, &cn, &cj, &ca));
3161: PetscCheck(bn == cn, ((PetscObject)A)->comm, PETSC_ERR_PLIB, "Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
3162: for (j = 0; j < bn; j++) {
3163: PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3164: if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
3165: maxentrycol = bj[j];
3166: maxentry = PetscRealPart(ba[j]);
3167: }
3168: if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
3169: maxdiffcol = bj[j];
3170: maxdiff = PetscRealPart(ca[j]);
3171: }
3172: if (rdiff > maxrdiff) {
3173: maxrdiffcol = bj[j];
3174: maxrdiff = rdiff;
3175: }
3176: }
3177: if (maxrdiff > 1) {
3178: 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));
3179: for (j = 0; j < bn; j++) {
3180: PetscReal rdiff;
3181: rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3182: if (rdiff > 1) PetscCall(PetscViewerASCIIPrintf(vstdout, " (%" PetscInt_FMT ",%g:%g)", bj[j], (double)PetscRealPart(ba[j]), (double)PetscRealPart(ca[j])));
3183: }
3184: PetscCall(PetscViewerASCIIPrintf(vstdout, "\n"));
3185: }
3186: PetscCall(MatRestoreRow(B, i, &bn, &bj, &ba));
3187: PetscCall(MatRestoreRow(Bfd, i, &cn, &cj, &ca));
3188: }
3189: }
3190: PetscCall(PetscViewerDestroy(&vdraw));
3191: PetscCall(MatDestroy(&Bfd));
3192: }
3193: }
3194: PetscFunctionReturn(PETSC_SUCCESS);
3195: }
3197: /*@C
3198: SNESSetJacobian - Sets the function to compute Jacobian as well as the
3199: location to store the matrix.
3201: Logically Collective
3203: Input Parameters:
3204: + snes - the `SNES` context
3205: . Amat - the matrix that defines the (approximate) Jacobian
3206: . Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
3207: . J - Jacobian evaluation routine (if `NULL` then `SNES` retains any previously set value), see `SNESJacobianFn` for details
3208: - ctx - [optional] user-defined context for private data for the
3209: Jacobian evaluation routine (may be `NULL`) (if `NULL` then `SNES` retains any previously set value)
3211: Level: beginner
3213: Notes:
3214: If the `Amat` matrix and `Pmat` matrix are different you must call `MatAssemblyBegin()`/`MatAssemblyEnd()` on
3215: each matrix.
3217: If you know the operator `Amat` has a null space you can use `MatSetNullSpace()` and `MatSetTransposeNullSpace()` to supply the null
3218: space to `Amat` and the `KSP` solvers will automatically use that null space as needed during the solution process.
3220: If using `SNESComputeJacobianDefaultColor()` to assemble a Jacobian, the `ctx` argument
3221: must be a `MatFDColoring`.
3223: Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian. One common
3224: example is to use the "Picard linearization" which only differentiates through the highest order parts of each term using `SNESSetPicard()`
3226: .seealso: [](ch_snes), `SNES`, `KSPSetOperators()`, `SNESSetFunction()`, `MatMFFDComputeJacobian()`, `SNESComputeJacobianDefaultColor()`, `MatStructure`,
3227: `SNESSetPicard()`, `SNESJacobianFn`, `SNESFunctionFn`
3228: @*/
3229: PetscErrorCode SNESSetJacobian(SNES snes, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
3230: {
3231: DM dm;
3233: PetscFunctionBegin;
3237: if (Amat) PetscCheckSameComm(snes, 1, Amat, 2);
3238: if (Pmat) PetscCheckSameComm(snes, 1, Pmat, 3);
3239: PetscCall(SNESGetDM(snes, &dm));
3240: PetscCall(DMSNESSetJacobian(dm, J, ctx));
3241: if (Amat) {
3242: PetscCall(PetscObjectReference((PetscObject)Amat));
3243: PetscCall(MatDestroy(&snes->jacobian));
3245: snes->jacobian = Amat;
3246: }
3247: if (Pmat) {
3248: PetscCall(PetscObjectReference((PetscObject)Pmat));
3249: PetscCall(MatDestroy(&snes->jacobian_pre));
3251: snes->jacobian_pre = Pmat;
3252: }
3253: PetscFunctionReturn(PETSC_SUCCESS);
3254: }
3256: /*@C
3257: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
3258: provided context for evaluating the Jacobian.
3260: Not Collective, but `Mat` object will be parallel if `SNES` is
3262: Input Parameter:
3263: . snes - the nonlinear solver context
3265: Output Parameters:
3266: + Amat - location to stash (approximate) Jacobian matrix (or `NULL`)
3267: . Pmat - location to stash matrix used to compute the preconditioner (or `NULL`)
3268: . J - location to put Jacobian function (or `NULL`), for calling sequence see `SNESJacobianFn`
3269: - ctx - location to stash Jacobian ctx (or `NULL`)
3271: Level: advanced
3273: .seealso: [](ch_snes), `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFn`, `SNESGetFunction()`
3274: @*/
3275: PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
3276: {
3277: DM dm;
3279: PetscFunctionBegin;
3281: if (Amat) *Amat = snes->jacobian;
3282: if (Pmat) *Pmat = snes->jacobian_pre;
3283: PetscCall(SNESGetDM(snes, &dm));
3284: PetscCall(DMSNESGetJacobian(dm, J, ctx));
3285: PetscFunctionReturn(PETSC_SUCCESS);
3286: }
3288: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3289: {
3290: DM dm;
3291: DMSNES sdm;
3293: PetscFunctionBegin;
3294: PetscCall(SNESGetDM(snes, &dm));
3295: PetscCall(DMGetDMSNES(dm, &sdm));
3296: if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3297: DM dm;
3298: PetscBool isdense, ismf;
3300: PetscCall(SNESGetDM(snes, &dm));
3301: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &isdense, MATSEQDENSE, MATMPIDENSE, MATDENSE, NULL));
3302: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &ismf, MATMFFD, MATSHELL, NULL));
3303: if (isdense) {
3304: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefault, NULL));
3305: } else if (!ismf) {
3306: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefaultColor, NULL));
3307: }
3308: }
3309: PetscFunctionReturn(PETSC_SUCCESS);
3310: }
3312: /*@
3313: SNESSetUp - Sets up the internal data structures for the later use
3314: of a nonlinear solver `SNESSolve()`.
3316: Collective
3318: Input Parameter:
3319: . snes - the `SNES` context
3321: Level: advanced
3323: Note:
3324: For basic use of the `SNES` solvers the user does not need to explicitly call
3325: `SNESSetUp()`, since these actions will automatically occur during
3326: the call to `SNESSolve()`. However, if one wishes to control this
3327: phase separately, `SNESSetUp()` should be called after `SNESCreate()`
3328: and optional routines of the form SNESSetXXX(), but before `SNESSolve()`.
3330: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`, `SNESDestroy()`, `SNESSetFromOptions()`
3331: @*/
3332: PetscErrorCode SNESSetUp(SNES snes)
3333: {
3334: DM dm;
3335: DMSNES sdm;
3336: SNESLineSearch linesearch, pclinesearch;
3337: void *lsprectx, *lspostctx;
3338: PetscBool mf_operator, mf;
3339: Vec f, fpc;
3340: void *funcctx;
3341: void *jacctx, *appctx;
3342: Mat j, jpre;
3343: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, void *);
3344: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *);
3345: SNESFunctionFn *func;
3346: SNESJacobianFn *jac;
3348: PetscFunctionBegin;
3350: if (snes->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
3351: PetscCall(PetscLogEventBegin(SNES_SetUp, snes, 0, 0, 0));
3353: if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, SNESNEWTONLS));
3355: PetscCall(SNESGetFunction(snes, &snes->vec_func, NULL, NULL));
3357: PetscCall(SNESGetDM(snes, &dm));
3358: PetscCall(DMGetDMSNES(dm, &sdm));
3359: PetscCall(SNESSetDefaultComputeJacobian(snes));
3361: if (!snes->vec_func) PetscCall(DMCreateGlobalVector(dm, &snes->vec_func));
3363: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
3365: if (snes->linesearch) {
3366: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
3367: PetscCall(SNESLineSearchSetFunction(snes->linesearch, SNESComputeFunction));
3368: }
3370: PetscCall(SNESGetUseMatrixFree(snes, &mf_operator, &mf));
3371: if (snes->npc && snes->npcside == PC_LEFT) {
3372: snes->mf = PETSC_TRUE;
3373: snes->mf_operator = PETSC_FALSE;
3374: }
3376: if (snes->npc) {
3377: /* copy the DM over */
3378: PetscCall(SNESGetDM(snes, &dm));
3379: PetscCall(SNESSetDM(snes->npc, dm));
3381: PetscCall(SNESGetFunction(snes, &f, &func, &funcctx));
3382: PetscCall(VecDuplicate(f, &fpc));
3383: PetscCall(SNESSetFunction(snes->npc, fpc, func, funcctx));
3384: PetscCall(SNESGetJacobian(snes, &j, &jpre, &jac, &jacctx));
3385: PetscCall(SNESSetJacobian(snes->npc, j, jpre, jac, jacctx));
3386: PetscCall(SNESGetApplicationContext(snes, &appctx));
3387: PetscCall(SNESSetApplicationContext(snes->npc, appctx));
3388: PetscCall(SNESSetUseMatrixFree(snes->npc, mf_operator, mf));
3389: PetscCall(VecDestroy(&fpc));
3391: /* copy the function pointers over */
3392: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)snes->npc));
3394: /* default to 1 iteration */
3395: PetscCall(SNESSetTolerances(snes->npc, 0.0, 0.0, 0.0, 1, snes->npc->max_funcs));
3396: if (snes->npcside == PC_RIGHT) {
3397: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_FINAL_ONLY));
3398: } else {
3399: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_NONE));
3400: }
3401: PetscCall(SNESSetFromOptions(snes->npc));
3403: /* copy the line search context over */
3404: if (snes->linesearch && snes->npc->linesearch) {
3405: PetscCall(SNESGetLineSearch(snes, &linesearch));
3406: PetscCall(SNESGetLineSearch(snes->npc, &pclinesearch));
3407: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
3408: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
3409: PetscCall(SNESLineSearchSetPreCheck(pclinesearch, precheck, lsprectx));
3410: PetscCall(SNESLineSearchSetPostCheck(pclinesearch, postcheck, lspostctx));
3411: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch));
3412: }
3413: }
3414: if (snes->mf) PetscCall(SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version));
3415: if (snes->ops->usercompute && !snes->ctx) PetscCallBack("SNES callback compute application context", (*snes->ops->usercompute)(snes, &snes->ctx));
3417: snes->jac_iter = 0;
3418: snes->pre_iter = 0;
3420: PetscTryTypeMethod(snes, setup);
3422: PetscCall(SNESSetDefaultComputeJacobian(snes));
3424: if (snes->npc && snes->npcside == PC_LEFT) {
3425: if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3426: if (snes->linesearch) {
3427: PetscCall(SNESGetLineSearch(snes, &linesearch));
3428: PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunctionDefaultNPC));
3429: }
3430: }
3431: }
3432: PetscCall(PetscLogEventEnd(SNES_SetUp, snes, 0, 0, 0));
3433: snes->setupcalled = PETSC_TRUE;
3434: PetscFunctionReturn(PETSC_SUCCESS);
3435: }
3437: /*@
3438: 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
3440: Collective
3442: Input Parameter:
3443: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3445: Level: intermediate
3447: Notes:
3448: Any options set on the `SNES` object, including those set with `SNESSetFromOptions()` remain.
3450: Call this if you wish to reuse a `SNES` but with different size vectors
3452: Also calls the application context destroy routine set with `SNESSetComputeApplicationContext()`
3454: .seealso: [](ch_snes), `SNES`, `SNESDestroy()`, `SNESCreate()`, `SNESSetUp()`, `SNESSolve()`
3455: @*/
3456: PetscErrorCode SNESReset(SNES snes)
3457: {
3458: PetscFunctionBegin;
3460: if (snes->ops->ctxdestroy && snes->ctx) {
3461: PetscCallBack("SNES callback destroy application context", (*snes->ops->ctxdestroy)(&snes->ctx));
3462: snes->ctx = NULL;
3463: }
3464: if (snes->npc) PetscCall(SNESReset(snes->npc));
3466: PetscTryTypeMethod(snes, reset);
3467: if (snes->ksp) PetscCall(KSPReset(snes->ksp));
3469: if (snes->linesearch) PetscCall(SNESLineSearchReset(snes->linesearch));
3471: PetscCall(VecDestroy(&snes->vec_rhs));
3472: PetscCall(VecDestroy(&snes->vec_sol));
3473: PetscCall(VecDestroy(&snes->vec_sol_update));
3474: PetscCall(VecDestroy(&snes->vec_func));
3475: PetscCall(MatDestroy(&snes->jacobian));
3476: PetscCall(MatDestroy(&snes->jacobian_pre));
3477: PetscCall(MatDestroy(&snes->picard));
3478: PetscCall(VecDestroyVecs(snes->nwork, &snes->work));
3479: PetscCall(VecDestroyVecs(snes->nvwork, &snes->vwork));
3481: snes->alwayscomputesfinalresidual = PETSC_FALSE;
3483: snes->nwork = snes->nvwork = 0;
3484: snes->setupcalled = PETSC_FALSE;
3485: PetscFunctionReturn(PETSC_SUCCESS);
3486: }
3488: /*@
3489: SNESConvergedReasonViewCancel - Clears all the reason view functions for a `SNES` object provided with `SNESConvergedReasonViewSet()` also
3490: removes the default viewer.
3492: Collective
3494: Input Parameter:
3495: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3497: Level: intermediate
3499: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESReset()`, `SNESConvergedReasonViewSet()`
3500: @*/
3501: PetscErrorCode SNESConvergedReasonViewCancel(SNES snes)
3502: {
3503: PetscInt i;
3505: PetscFunctionBegin;
3507: for (i = 0; i < snes->numberreasonviews; i++) {
3508: if (snes->reasonviewdestroy[i]) PetscCall((*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]));
3509: }
3510: snes->numberreasonviews = 0;
3511: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
3512: PetscFunctionReturn(PETSC_SUCCESS);
3513: }
3515: /*@
3516: SNESDestroy - Destroys the nonlinear solver context that was created
3517: with `SNESCreate()`.
3519: Collective
3521: Input Parameter:
3522: . snes - the `SNES` context
3524: Level: beginner
3526: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`
3527: @*/
3528: PetscErrorCode SNESDestroy(SNES *snes)
3529: {
3530: DM dm;
3532: PetscFunctionBegin;
3533: if (!*snes) PetscFunctionReturn(PETSC_SUCCESS);
3535: if (--((PetscObject)*snes)->refct > 0) {
3536: *snes = NULL;
3537: PetscFunctionReturn(PETSC_SUCCESS);
3538: }
3540: PetscCall(SNESReset(*snes));
3541: PetscCall(SNESDestroy(&(*snes)->npc));
3543: /* if memory was published with SAWs then destroy it */
3544: PetscCall(PetscObjectSAWsViewOff((PetscObject)*snes));
3545: PetscTryTypeMethod(*snes, destroy);
3547: dm = (*snes)->dm;
3548: while (dm) {
3549: PetscCall(DMCoarsenHookRemove(dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, *snes));
3550: PetscCall(DMGetCoarseDM(dm, &dm));
3551: }
3553: PetscCall(DMDestroy(&(*snes)->dm));
3554: PetscCall(KSPDestroy(&(*snes)->ksp));
3555: PetscCall(SNESLineSearchDestroy(&(*snes)->linesearch));
3557: PetscCall(PetscFree((*snes)->kspconvctx));
3558: if ((*snes)->ops->convergeddestroy) PetscCall((*(*snes)->ops->convergeddestroy)((*snes)->cnvP));
3559: if ((*snes)->conv_hist_alloc) PetscCall(PetscFree2((*snes)->conv_hist, (*snes)->conv_hist_its));
3560: PetscCall(SNESMonitorCancel(*snes));
3561: PetscCall(SNESConvergedReasonViewCancel(*snes));
3562: PetscCall(PetscHeaderDestroy(snes));
3563: PetscFunctionReturn(PETSC_SUCCESS);
3564: }
3566: /* ----------- Routines to set solver parameters ---------- */
3568: /*@
3569: SNESSetLagPreconditioner - Sets when the preconditioner is rebuilt in the nonlinear solve `SNESSolve()`.
3571: Logically Collective
3573: Input Parameters:
3574: + snes - the `SNES` context
3575: - lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3576: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3578: Options Database Keys:
3579: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3580: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3581: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3582: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3584: Level: intermediate
3586: Notes:
3587: The default is 1
3589: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagPreconditionerPersists()` was called
3591: `SNESSetLagPreconditionerPersists()` allows using the same uniform lagging (for example every second linear solve) across multiple nonlinear solves.
3593: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetLagPreconditionerPersists()`,
3594: `SNESSetLagJacobianPersists()`, `SNES`, `SNESSolve()`
3595: @*/
3596: PetscErrorCode SNESSetLagPreconditioner(SNES snes, PetscInt lag)
3597: {
3598: PetscFunctionBegin;
3600: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3601: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3603: snes->lagpreconditioner = lag;
3604: PetscFunctionReturn(PETSC_SUCCESS);
3605: }
3607: /*@
3608: SNESSetGridSequence - sets the number of steps of grid sequencing that `SNES` will do
3610: Logically Collective
3612: Input Parameters:
3613: + snes - the `SNES` context
3614: - steps - the number of refinements to do, defaults to 0
3616: Options Database Key:
3617: . -snes_grid_sequence <steps> - Use grid sequencing to generate initial guess
3619: Level: intermediate
3621: Notes:
3622: Once grid sequencing is turned on `SNESSolve()` will automatically perform the solve on each grid refinement.
3624: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3626: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetGridSequence()`,
3627: `SNESSetDM()`, `SNESSolve()`
3628: @*/
3629: PetscErrorCode SNESSetGridSequence(SNES snes, PetscInt steps)
3630: {
3631: PetscFunctionBegin;
3634: snes->gridsequence = steps;
3635: PetscFunctionReturn(PETSC_SUCCESS);
3636: }
3638: /*@
3639: SNESGetGridSequence - gets the number of steps of grid sequencing that `SNES` will do
3641: Logically Collective
3643: Input Parameter:
3644: . snes - the `SNES` context
3646: Output Parameter:
3647: . steps - the number of refinements to do, defaults to 0
3649: Level: intermediate
3651: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetGridSequence()`
3652: @*/
3653: PetscErrorCode SNESGetGridSequence(SNES snes, PetscInt *steps)
3654: {
3655: PetscFunctionBegin;
3657: *steps = snes->gridsequence;
3658: PetscFunctionReturn(PETSC_SUCCESS);
3659: }
3661: /*@
3662: SNESGetLagPreconditioner - Return how often the preconditioner is rebuilt
3664: Not Collective
3666: Input Parameter:
3667: . snes - the `SNES` context
3669: Output Parameter:
3670: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3671: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3673: Level: intermediate
3675: Notes:
3676: The default is 1
3678: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3680: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3681: @*/
3682: PetscErrorCode SNESGetLagPreconditioner(SNES snes, PetscInt *lag)
3683: {
3684: PetscFunctionBegin;
3686: *lag = snes->lagpreconditioner;
3687: PetscFunctionReturn(PETSC_SUCCESS);
3688: }
3690: /*@
3691: SNESSetLagJacobian - Set when the Jacobian is rebuilt in the nonlinear solve. See `SNESSetLagPreconditioner()` for determining how
3692: often the preconditioner is rebuilt.
3694: Logically Collective
3696: Input Parameters:
3697: + snes - the `SNES` context
3698: - lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3699: the Jacobian is built etc. -2 means rebuild at next chance but then never again
3701: Options Database Keys:
3702: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3703: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3704: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3705: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag.
3707: Level: intermediate
3709: Notes:
3710: The default is 1
3712: The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3714: 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
3715: at the next Newton step but never again (unless it is reset to another value)
3717: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagPreconditioner()`, `SNESGetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3718: @*/
3719: PetscErrorCode SNESSetLagJacobian(SNES snes, PetscInt lag)
3720: {
3721: PetscFunctionBegin;
3723: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3724: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3726: snes->lagjacobian = lag;
3727: PetscFunctionReturn(PETSC_SUCCESS);
3728: }
3730: /*@
3731: SNESGetLagJacobian - Get how often the Jacobian is rebuilt. See `SNESGetLagPreconditioner()` to determine when the preconditioner is rebuilt
3733: Not Collective
3735: Input Parameter:
3736: . snes - the `SNES` context
3738: Output Parameter:
3739: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3740: the Jacobian is built etc.
3742: Level: intermediate
3744: Notes:
3745: The default is 1
3747: The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagJacobianPersists()` was called.
3749: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobian()`, `SNESSetLagPreconditioner()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3751: @*/
3752: PetscErrorCode SNESGetLagJacobian(SNES snes, PetscInt *lag)
3753: {
3754: PetscFunctionBegin;
3756: *lag = snes->lagjacobian;
3757: PetscFunctionReturn(PETSC_SUCCESS);
3758: }
3760: /*@
3761: SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple nonlinear solves
3763: Logically collective
3765: Input Parameters:
3766: + snes - the `SNES` context
3767: - flg - jacobian lagging persists if true
3769: Options Database Keys:
3770: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3771: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3772: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3773: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3775: Level: advanced
3777: Notes:
3778: Normally when `SNESSetLagJacobian()` is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3780: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3781: several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3782: timesteps may present huge efficiency gains.
3784: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditionerPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`
3785: @*/
3786: PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
3787: {
3788: PetscFunctionBegin;
3791: snes->lagjac_persist = flg;
3792: PetscFunctionReturn(PETSC_SUCCESS);
3793: }
3795: /*@
3796: SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves
3798: Logically Collective
3800: Input Parameters:
3801: + snes - the `SNES` context
3802: - flg - preconditioner lagging persists if true
3804: Options Database Keys:
3805: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3806: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3807: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3808: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3810: Level: developer
3812: Notes:
3813: Normally when `SNESSetLagPreconditioner()` is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3815: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3816: by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3817: several timesteps may present huge efficiency gains.
3819: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobianPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagPreconditioner()`
3820: @*/
3821: PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)
3822: {
3823: PetscFunctionBegin;
3826: snes->lagpre_persist = flg;
3827: PetscFunctionReturn(PETSC_SUCCESS);
3828: }
3830: /*@
3831: SNESSetForceIteration - force `SNESSolve()` to take at least one iteration regardless of the initial residual norm
3833: Logically Collective
3835: Input Parameters:
3836: + snes - the `SNES` context
3837: - force - `PETSC_TRUE` require at least one iteration
3839: Options Database Key:
3840: . -snes_force_iteration <force> - Sets forcing an iteration
3842: Level: intermediate
3844: Note:
3845: This is used sometimes with `TS` to prevent `TS` from detecting a false steady state solution
3847: .seealso: [](ch_snes), `SNES`, `TS`, `SNESSetDivergenceTolerance()`
3848: @*/
3849: PetscErrorCode SNESSetForceIteration(SNES snes, PetscBool force)
3850: {
3851: PetscFunctionBegin;
3853: snes->forceiteration = force;
3854: PetscFunctionReturn(PETSC_SUCCESS);
3855: }
3857: /*@
3858: SNESGetForceIteration - Check whether or not `SNESSolve()` take at least one iteration regardless of the initial residual norm
3860: Logically Collective
3862: Input Parameter:
3863: . snes - the `SNES` context
3865: Output Parameter:
3866: . force - `PETSC_TRUE` requires at least one iteration.
3868: Level: intermediate
3870: .seealso: [](ch_snes), `SNES`, `SNESSetForceIteration()`, `SNESSetDivergenceTolerance()`
3871: @*/
3872: PetscErrorCode SNESGetForceIteration(SNES snes, PetscBool *force)
3873: {
3874: PetscFunctionBegin;
3876: *force = snes->forceiteration;
3877: PetscFunctionReturn(PETSC_SUCCESS);
3878: }
3880: /*@
3881: SNESSetTolerances - Sets various parameters used in `SNES` convergence tests.
3883: Logically Collective
3885: Input Parameters:
3886: + snes - the `SNES` context
3887: . abstol - the absolute convergence tolerance, $ F(x^n) \le abstol $
3888: . rtol - the relative convergence tolerance, $ F(x^n) \le reltol * F(x^0) $
3889: . stol - convergence tolerance in terms of the norm of the change in the solution between steps, || delta x || < stol*|| x ||
3890: . maxit - the maximum number of iterations allowed in the solver, default 50.
3891: - maxf - the maximum number of function evaluations allowed in the solver (use `PETSC_UNLIMITED` indicates no limit), default 10,000
3893: Options Database Keys:
3894: + -snes_atol <abstol> - Sets `abstol`
3895: . -snes_rtol <rtol> - Sets `rtol`
3896: . -snes_stol <stol> - Sets `stol`
3897: . -snes_max_it <maxit> - Sets `maxit`
3898: - -snes_max_funcs <maxf> - Sets `maxf` (use `unlimited` to have no maximum)
3900: Level: intermediate
3902: Note:
3903: All parameters must be non-negative
3905: Use `PETSC_CURRENT` to retain the current value of any parameter and `PETSC_DETERMINE` to use the default value for the given `SNES`.
3906: The default value is the value in the object when its type is set.
3908: Use `PETSC_UNLIMITED` on `maxit` or `maxf` to indicate there is no bound on the number of iterations or number of function evaluations.
3910: Fortran Note:
3911: Use `PETSC_CURRENT_INTEGER`, `PETSC_CURRENT_REAL`, `PETSC_UNLIMITED_INTEGER`, `PETSC_DETERMINE_INTEGER`, or `PETSC_DETERMINE_REAL`
3913: .seealso: [](ch_snes), `SNESSolve()`, `SNES`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`
3914: @*/
3915: PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
3916: {
3917: PetscFunctionBegin;
3925: if (abstol == (PetscReal)PETSC_DETERMINE) {
3926: snes->abstol = snes->default_abstol;
3927: } else if (abstol != (PetscReal)PETSC_CURRENT) {
3928: PetscCheck(abstol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %g must be non-negative", (double)abstol);
3929: snes->abstol = abstol;
3930: }
3932: if (rtol == (PetscReal)PETSC_DETERMINE) {
3933: snes->rtol = snes->default_rtol;
3934: } else if (rtol != (PetscReal)PETSC_CURRENT) {
3935: 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);
3936: snes->rtol = rtol;
3937: }
3939: if (stol == (PetscReal)PETSC_DETERMINE) {
3940: snes->stol = snes->default_stol;
3941: } else if (stol != (PetscReal)PETSC_CURRENT) {
3942: PetscCheck(stol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Step tolerance %g must be non-negative", (double)stol);
3943: snes->stol = stol;
3944: }
3946: if (maxit == PETSC_DETERMINE) {
3947: snes->max_its = snes->default_max_its;
3948: } else if (maxit == PETSC_UNLIMITED) {
3949: snes->max_its = PETSC_INT_MAX;
3950: } else if (maxit != PETSC_CURRENT) {
3951: PetscCheck(maxit >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", maxit);
3952: snes->max_its = maxit;
3953: }
3955: if (maxf == PETSC_DETERMINE) {
3956: snes->max_funcs = snes->default_max_funcs;
3957: } else if (maxf == PETSC_UNLIMITED || maxf == -1) {
3958: snes->max_funcs = PETSC_UNLIMITED;
3959: } else if (maxf != PETSC_CURRENT) {
3960: PetscCheck(maxf >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of function evaluations %" PetscInt_FMT " must be nonnegative", maxf);
3961: snes->max_funcs = maxf;
3962: }
3963: PetscFunctionReturn(PETSC_SUCCESS);
3964: }
3966: /*@
3967: SNESSetDivergenceTolerance - Sets the divergence tolerance used for the `SNES` divergence test.
3969: Logically Collective
3971: Input Parameters:
3972: + snes - the `SNES` context
3973: - 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
3974: is stopped due to divergence.
3976: Options Database Key:
3977: . -snes_divergence_tolerance <divtol> - Sets `divtol`
3979: Level: intermediate
3981: Notes:
3982: Use `PETSC_DETERMINE` to use the default value from when the object's type was set.
3984: Fortran Note:
3985: Use ``PETSC_DETERMINE_REAL` or `PETSC_UNLIMITED_REAL`
3987: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetTolerances()`, `SNESGetDivergenceTolerance()`
3988: @*/
3989: PetscErrorCode SNESSetDivergenceTolerance(SNES snes, PetscReal divtol)
3990: {
3991: PetscFunctionBegin;
3995: if (divtol == (PetscReal)PETSC_DETERMINE) {
3996: snes->divtol = snes->default_divtol;
3997: } else if (divtol == (PetscReal)PETSC_UNLIMITED || divtol == -1) {
3998: snes->divtol = PETSC_UNLIMITED;
3999: } else if (divtol != (PetscReal)PETSC_CURRENT) {
4000: PetscCheck(divtol >= 1.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Divergence tolerance %g must be greater than 1.0", (double)divtol);
4001: snes->divtol = divtol;
4002: }
4003: PetscFunctionReturn(PETSC_SUCCESS);
4004: }
4006: /*@
4007: SNESGetTolerances - Gets various parameters used in `SNES` convergence tests.
4009: Not Collective
4011: Input Parameter:
4012: . snes - the `SNES` context
4014: Output Parameters:
4015: + atol - the absolute convergence tolerance
4016: . rtol - the relative convergence tolerance
4017: . stol - convergence tolerance in terms of the norm of the change in the solution between steps
4018: . maxit - the maximum number of iterations allowed
4019: - maxf - the maximum number of function evaluations allowed, `PETSC_UNLIMITED` indicates no bound
4021: Level: intermediate
4023: Notes:
4024: See `SNESSetTolerances()` for details on the parameters.
4026: The user can specify `NULL` for any parameter that is not needed.
4028: .seealso: [](ch_snes), `SNES`, `SNESSetTolerances()`
4029: @*/
4030: PetscErrorCode SNESGetTolerances(SNES snes, PetscReal *atol, PetscReal *rtol, PetscReal *stol, PetscInt *maxit, PetscInt *maxf)
4031: {
4032: PetscFunctionBegin;
4034: if (atol) *atol = snes->abstol;
4035: if (rtol) *rtol = snes->rtol;
4036: if (stol) *stol = snes->stol;
4037: if (maxit) *maxit = snes->max_its;
4038: if (maxf) *maxf = snes->max_funcs;
4039: PetscFunctionReturn(PETSC_SUCCESS);
4040: }
4042: /*@
4043: SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.
4045: Not Collective
4047: Input Parameters:
4048: + snes - the `SNES` context
4049: - divtol - divergence tolerance
4051: Level: intermediate
4053: .seealso: [](ch_snes), `SNES`, `SNESSetDivergenceTolerance()`
4054: @*/
4055: PetscErrorCode SNESGetDivergenceTolerance(SNES snes, PetscReal *divtol)
4056: {
4057: PetscFunctionBegin;
4059: if (divtol) *divtol = snes->divtol;
4060: PetscFunctionReturn(PETSC_SUCCESS);
4061: }
4063: PETSC_INTERN PetscErrorCode SNESMonitorRange_Private(SNES, PetscInt, PetscReal *);
4065: PetscErrorCode SNESMonitorLGRange(SNES snes, PetscInt n, PetscReal rnorm, void *monctx)
4066: {
4067: PetscDrawLG lg;
4068: PetscReal x, y, per;
4069: PetscViewer v = (PetscViewer)monctx;
4070: static PetscReal prev; /* should be in the context */
4071: PetscDraw draw;
4073: PetscFunctionBegin;
4075: PetscCall(PetscViewerDrawGetDrawLG(v, 0, &lg));
4076: if (!n) PetscCall(PetscDrawLGReset(lg));
4077: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4078: PetscCall(PetscDrawSetTitle(draw, "Residual norm"));
4079: x = (PetscReal)n;
4080: if (rnorm > 0.0) y = PetscLog10Real(rnorm);
4081: else y = -15.0;
4082: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4083: if (n < 20 || !(n % 5) || snes->reason) {
4084: PetscCall(PetscDrawLGDraw(lg));
4085: PetscCall(PetscDrawLGSave(lg));
4086: }
4088: PetscCall(PetscViewerDrawGetDrawLG(v, 1, &lg));
4089: if (!n) PetscCall(PetscDrawLGReset(lg));
4090: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4091: PetscCall(PetscDrawSetTitle(draw, "% elements > .2*max element"));
4092: PetscCall(SNESMonitorRange_Private(snes, n, &per));
4093: x = (PetscReal)n;
4094: y = 100.0 * per;
4095: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4096: if (n < 20 || !(n % 5) || snes->reason) {
4097: PetscCall(PetscDrawLGDraw(lg));
4098: PetscCall(PetscDrawLGSave(lg));
4099: }
4101: PetscCall(PetscViewerDrawGetDrawLG(v, 2, &lg));
4102: if (!n) {
4103: prev = rnorm;
4104: PetscCall(PetscDrawLGReset(lg));
4105: }
4106: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4107: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm"));
4108: x = (PetscReal)n;
4109: y = (prev - rnorm) / prev;
4110: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4111: if (n < 20 || !(n % 5) || snes->reason) {
4112: PetscCall(PetscDrawLGDraw(lg));
4113: PetscCall(PetscDrawLGSave(lg));
4114: }
4116: PetscCall(PetscViewerDrawGetDrawLG(v, 3, &lg));
4117: if (!n) PetscCall(PetscDrawLGReset(lg));
4118: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4119: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm*(% > .2 max)"));
4120: x = (PetscReal)n;
4121: y = (prev - rnorm) / (prev * per);
4122: if (n > 2) { /*skip initial crazy value */
4123: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4124: }
4125: if (n < 20 || !(n % 5) || snes->reason) {
4126: PetscCall(PetscDrawLGDraw(lg));
4127: PetscCall(PetscDrawLGSave(lg));
4128: }
4129: prev = rnorm;
4130: PetscFunctionReturn(PETSC_SUCCESS);
4131: }
4133: /*@
4134: SNESConverged - Run the convergence test and update the `SNESConvergedReason`.
4136: Collective
4138: Input Parameters:
4139: + snes - the `SNES` context
4140: . it - current iteration
4141: . xnorm - 2-norm of current iterate
4142: . snorm - 2-norm of current step
4143: - fnorm - 2-norm of function
4145: Level: developer
4147: Note:
4148: This routine is called by the `SNESSolve()` implementations.
4149: It does not typically need to be called by the user.
4151: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4152: @*/
4153: PetscErrorCode SNESConverged(SNES snes, PetscInt it, PetscReal xnorm, PetscReal snorm, PetscReal fnorm)
4154: {
4155: PetscFunctionBegin;
4156: if (!snes->reason) {
4157: if (snes->normschedule == SNES_NORM_ALWAYS) PetscUseTypeMethod(snes, converged, it, xnorm, snorm, fnorm, &snes->reason, snes->cnvP);
4158: if (it == snes->max_its && !snes->reason) {
4159: if (snes->normschedule == SNES_NORM_ALWAYS) {
4160: PetscCall(PetscInfo(snes, "Maximum number of iterations has been reached: %" PetscInt_FMT "\n", snes->max_its));
4161: snes->reason = SNES_DIVERGED_MAX_IT;
4162: } else snes->reason = SNES_CONVERGED_ITS;
4163: }
4164: }
4165: PetscFunctionReturn(PETSC_SUCCESS);
4166: }
4168: /*@
4169: SNESMonitor - runs any `SNES` monitor routines provided with `SNESMonitor()` or the options database
4171: Collective
4173: Input Parameters:
4174: + snes - nonlinear solver context obtained from `SNESCreate()`
4175: . iter - current iteration number
4176: - rnorm - current relative norm of the residual
4178: Level: developer
4180: Note:
4181: This routine is called by the `SNESSolve()` implementations.
4182: It does not typically need to be called by the user.
4184: .seealso: [](ch_snes), `SNES`, `SNESMonitorSet()`
4185: @*/
4186: PetscErrorCode SNESMonitor(SNES snes, PetscInt iter, PetscReal rnorm)
4187: {
4188: PetscInt i, n = snes->numbermonitors;
4190: PetscFunctionBegin;
4191: if (n > 0) SNESCheckFunctionNorm(snes, rnorm);
4192: PetscCall(VecLockReadPush(snes->vec_sol));
4193: for (i = 0; i < n; i++) PetscCall((*snes->monitor[i])(snes, iter, rnorm, snes->monitorcontext[i]));
4194: PetscCall(VecLockReadPop(snes->vec_sol));
4195: PetscFunctionReturn(PETSC_SUCCESS);
4196: }
4198: /* ------------ Routines to set performance monitoring options ----------- */
4200: /*MC
4201: SNESMonitorFunction - functional form passed to `SNESMonitorSet()` to monitor convergence of nonlinear solver
4203: Synopsis:
4204: #include <petscsnes.h>
4205: PetscErrorCode SNESMonitorFunction(SNES snes, PetscInt its, PetscReal norm, void *mctx)
4207: Collective
4209: Input Parameters:
4210: + snes - the `SNES` context
4211: . its - iteration number
4212: . norm - 2-norm function value (may be estimated)
4213: - mctx - [optional] monitoring context
4215: Level: advanced
4217: .seealso: [](ch_snes), `SNESMonitorSet()`, `SNESMonitorSet()`, `SNESMonitorGet()`
4218: M*/
4220: /*@C
4221: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
4222: iteration of the `SNES` nonlinear solver to display the iteration's
4223: progress.
4225: Logically Collective
4227: Input Parameters:
4228: + snes - the `SNES` context
4229: . f - the monitor function, for the calling sequence see `SNESMonitorFunction`
4230: . mctx - [optional] user-defined context for private data for the monitor routine (use `NULL` if no context is desired)
4231: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4233: Options Database Keys:
4234: + -snes_monitor - sets `SNESMonitorDefault()`
4235: . -snes_monitor draw::draw_lg - sets line graph monitor,
4236: - -snes_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `SNESMonitorSet()`, but does not cancel those set via
4237: the options database.
4239: Level: intermediate
4241: Note:
4242: Several different monitoring routines may be set by calling
4243: `SNESMonitorSet()` multiple times; all will be called in the
4244: order in which they were set.
4246: Fortran Note:
4247: Only a single monitor function can be set for each `SNES` object
4249: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESMonitorDefault()`, `SNESMonitorCancel()`, `SNESMonitorFunction`, `PetscCtxDestroyFn`
4250: @*/
4251: PetscErrorCode SNESMonitorSet(SNES snes, PetscErrorCode (*f)(SNES, PetscInt, PetscReal, void *), void *mctx, PetscCtxDestroyFn *monitordestroy)
4252: {
4253: PetscInt i;
4254: PetscBool identical;
4256: PetscFunctionBegin;
4258: for (i = 0; i < snes->numbermonitors; i++) {
4259: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))f, mctx, monitordestroy, (PetscErrorCode (*)(void))snes->monitor[i], snes->monitorcontext[i], snes->monitordestroy[i], &identical));
4260: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4261: }
4262: PetscCheck(snes->numbermonitors < MAXSNESMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
4263: snes->monitor[snes->numbermonitors] = f;
4264: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
4265: snes->monitorcontext[snes->numbermonitors++] = mctx;
4266: PetscFunctionReturn(PETSC_SUCCESS);
4267: }
4269: /*@
4270: SNESMonitorCancel - Clears all the monitor functions for a `SNES` object.
4272: Logically Collective
4274: Input Parameter:
4275: . snes - the `SNES` context
4277: Options Database Key:
4278: . -snes_monitor_cancel - cancels all monitors that have been hardwired
4279: into a code by calls to `SNESMonitorSet()`, but does not cancel those
4280: set via the options database
4282: Level: intermediate
4284: Note:
4285: There is no way to clear one specific monitor from a `SNES` object.
4287: .seealso: [](ch_snes), `SNES`, `SNESMonitorGet()`, `SNESMonitorDefault()`, `SNESMonitorSet()`
4288: @*/
4289: PetscErrorCode SNESMonitorCancel(SNES snes)
4290: {
4291: PetscInt i;
4293: PetscFunctionBegin;
4295: for (i = 0; i < snes->numbermonitors; i++) {
4296: if (snes->monitordestroy[i]) PetscCall((*snes->monitordestroy[i])(&snes->monitorcontext[i]));
4297: }
4298: snes->numbermonitors = 0;
4299: PetscFunctionReturn(PETSC_SUCCESS);
4300: }
4302: /*MC
4303: SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver
4305: Synopsis:
4306: #include <petscsnes.h>
4307: PetscErrorCode SNESConvergenceTest(SNES snes, PetscInt it, PetscReal xnorm, PetscReal gnorm, PetscReal f, SNESConvergedReason *reason, void *cctx)
4309: Collective
4311: Input Parameters:
4312: + snes - the `SNES` context
4313: . it - current iteration (0 is the first and is before any Newton step)
4314: . xnorm - 2-norm of current iterate
4315: . gnorm - 2-norm of current step
4316: . f - 2-norm of function
4317: - cctx - [optional] convergence context
4319: Output Parameter:
4320: . reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected
4322: Level: intermediate
4324: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4325: M*/
4327: /*@C
4328: SNESSetConvergenceTest - Sets the function that is to be used
4329: to test for convergence of the nonlinear iterative solution.
4331: Logically Collective
4333: Input Parameters:
4334: + snes - the `SNES` context
4335: . SNESConvergenceTestFunction - routine to test for convergence
4336: . cctx - [optional] context for private data for the convergence routine (may be `NULL`)
4337: - destroy - [optional] destructor for the context (may be `NULL`; `PETSC_NULL_FUNCTION` in Fortran)
4339: Level: advanced
4341: .seealso: [](ch_snes), `SNES`, `SNESConvergedDefault()`, `SNESConvergedSkip()`, `SNESConvergenceTestFunction`
4342: @*/
4343: PetscErrorCode SNESSetConvergenceTest(SNES snes, PetscErrorCode (*SNESConvergenceTestFunction)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *cctx, PetscErrorCode (*destroy)(void *))
4344: {
4345: PetscFunctionBegin;
4347: if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4348: if (snes->ops->convergeddestroy) PetscCall((*snes->ops->convergeddestroy)(snes->cnvP));
4349: snes->ops->converged = SNESConvergenceTestFunction;
4350: snes->ops->convergeddestroy = destroy;
4351: snes->cnvP = cctx;
4352: PetscFunctionReturn(PETSC_SUCCESS);
4353: }
4355: /*@
4356: SNESGetConvergedReason - Gets the reason the `SNES` iteration was stopped, which may be due to convergence, divergence, or stagnation
4358: Not Collective
4360: Input Parameter:
4361: . snes - the `SNES` context
4363: Output Parameter:
4364: . reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` for the individual convergence tests for complete lists
4366: Options Database Key:
4367: . -snes_converged_reason - prints the reason to standard out
4369: Level: intermediate
4371: Note:
4372: Should only be called after the call the `SNESSolve()` is complete, if it is called earlier it returns the value `SNES__CONVERGED_ITERATING`.
4374: .seealso: [](ch_snes), `SNESSolve()`, `SNESSetConvergenceTest()`, `SNESSetConvergedReason()`, `SNESConvergedReason`, `SNESGetConvergedReasonString()`
4375: @*/
4376: PetscErrorCode SNESGetConvergedReason(SNES snes, SNESConvergedReason *reason)
4377: {
4378: PetscFunctionBegin;
4380: PetscAssertPointer(reason, 2);
4381: *reason = snes->reason;
4382: PetscFunctionReturn(PETSC_SUCCESS);
4383: }
4385: /*@C
4386: SNESGetConvergedReasonString - Return a human readable string for `SNESConvergedReason`
4388: Not Collective
4390: Input Parameter:
4391: . snes - the `SNES` context
4393: Output Parameter:
4394: . strreason - a human readable string that describes `SNES` converged reason
4396: Level: beginner
4398: .seealso: [](ch_snes), `SNES`, `SNESGetConvergedReason()`
4399: @*/
4400: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char **strreason)
4401: {
4402: PetscFunctionBegin;
4404: PetscAssertPointer(strreason, 2);
4405: *strreason = SNESConvergedReasons[snes->reason];
4406: PetscFunctionReturn(PETSC_SUCCESS);
4407: }
4409: /*@
4410: SNESSetConvergedReason - Sets the reason the `SNES` iteration was stopped.
4412: Not Collective
4414: Input Parameters:
4415: + snes - the `SNES` context
4416: - reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` or the
4417: manual pages for the individual convergence tests for complete lists
4419: Level: developer
4421: Developer Note:
4422: Called inside the various `SNESSolve()` implementations
4424: .seealso: [](ch_snes), `SNESGetConvergedReason()`, `SNESSetConvergenceTest()`, `SNESConvergedReason`
4425: @*/
4426: PetscErrorCode SNESSetConvergedReason(SNES snes, SNESConvergedReason reason)
4427: {
4428: PetscFunctionBegin;
4430: PetscCheck(!snes->errorifnotconverged || reason > 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_PLIB, "SNES code should have previously errored due to negative reason");
4431: snes->reason = reason;
4432: PetscFunctionReturn(PETSC_SUCCESS);
4433: }
4435: /*@
4436: SNESSetConvergenceHistory - Sets the arrays used to hold the convergence history.
4438: Logically Collective
4440: Input Parameters:
4441: + snes - iterative context obtained from `SNESCreate()`
4442: . a - array to hold history, this array will contain the function norms computed at each step
4443: . its - integer array holds the number of linear iterations for each solve.
4444: . na - size of `a` and `its`
4445: - reset - `PETSC_TRUE` indicates each new nonlinear solve resets the history counter to zero,
4446: else it continues storing new values for new nonlinear solves after the old ones
4448: Level: intermediate
4450: Notes:
4451: If 'a' and 'its' are `NULL` then space is allocated for the history. If 'na' is `PETSC_DECIDE` (or, deprecated, `PETSC_DEFAULT`) then a
4452: default array of length 1,000 is allocated.
4454: This routine is useful, e.g., when running a code for purposes
4455: of accurate performance monitoring, when no I/O should be done
4456: during the section of code that is being timed.
4458: If the arrays run out of space after a number of iterations then the later values are not saved in the history
4460: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergenceHistory()`
4461: @*/
4462: PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)
4463: {
4464: PetscFunctionBegin;
4466: if (a) PetscAssertPointer(a, 2);
4467: if (its) PetscAssertPointer(its, 3);
4468: if (!a) {
4469: if (na == PETSC_DECIDE) na = 1000;
4470: PetscCall(PetscCalloc2(na, &a, na, &its));
4471: snes->conv_hist_alloc = PETSC_TRUE;
4472: }
4473: snes->conv_hist = a;
4474: snes->conv_hist_its = its;
4475: snes->conv_hist_max = (size_t)na;
4476: snes->conv_hist_len = 0;
4477: snes->conv_hist_reset = reset;
4478: PetscFunctionReturn(PETSC_SUCCESS);
4479: }
4481: #if defined(PETSC_HAVE_MATLAB)
4482: #include <engine.h> /* MATLAB include file */
4483: #include <mex.h> /* MATLAB include file */
4485: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4486: {
4487: mxArray *mat;
4488: PetscInt i;
4489: PetscReal *ar;
4491: mat = mxCreateDoubleMatrix(snes->conv_hist_len, 1, mxREAL);
4492: ar = (PetscReal *)mxGetData(mat);
4493: for (i = 0; i < snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4494: return mat;
4495: }
4496: #endif
4498: /*@C
4499: SNESGetConvergenceHistory - Gets the arrays used to hold the convergence history.
4501: Not Collective
4503: Input Parameter:
4504: . snes - iterative context obtained from `SNESCreate()`
4506: Output Parameters:
4507: + a - array to hold history, usually was set with `SNESSetConvergenceHistory()`
4508: . its - integer array holds the number of linear iterations (or
4509: negative if not converged) for each solve.
4510: - na - size of `a` and `its`
4512: Level: intermediate
4514: Note:
4515: This routine is useful, e.g., when running a code for purposes
4516: of accurate performance monitoring, when no I/O should be done
4517: during the section of code that is being timed.
4519: Fortran Notes:
4520: Return the arrays with ``SNESRestoreConvergenceHistory()`
4522: Use the arguments
4523: .vb
4524: PetscReal, pointer :: a(:)
4525: PetscInt, pointer :: its(:)
4526: .ve
4528: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetConvergenceHistory()`
4529: @*/
4530: PetscErrorCode SNESGetConvergenceHistory(SNES snes, PetscReal *a[], PetscInt *its[], PetscInt *na)
4531: {
4532: PetscFunctionBegin;
4534: if (a) *a = snes->conv_hist;
4535: if (its) *its = snes->conv_hist_its;
4536: if (na) *na = (PetscInt)snes->conv_hist_len;
4537: PetscFunctionReturn(PETSC_SUCCESS);
4538: }
4540: /*@C
4541: SNESSetUpdate - Sets the general-purpose update function called
4542: at the beginning of every iteration of the nonlinear solve. Specifically
4543: it is called just before the Jacobian is "evaluated" and after the function
4544: evaluation.
4546: Logically Collective
4548: Input Parameters:
4549: + snes - The nonlinear solver context
4550: - func - The update function; for calling sequence see `SNESUpdateFn`
4552: Level: advanced
4554: Notes:
4555: 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
4556: to `SNESSetFunction()`, or `SNESSetPicard()`
4557: This is not used by most users, and it is intended to provide a general hook that is run
4558: right before the direction step is computed.
4560: Users are free to modify the current residual vector,
4561: the current linearization point, or any other vector associated to the specific solver used.
4562: If such modifications take place, it is the user responsibility to update all the relevant
4563: vectors. For example, if one is adjusting the model parameters at each Newton step their code may look like
4564: .vb
4565: PetscErrorCode update(SNES snes, PetscInt iteration)
4566: {
4567: PetscFunctionBeginUser;
4568: if (iteration > 0) {
4569: // update the model parameters here
4570: Vec x,f;
4571: PetscCall(SNESGetSolution(snes,&x));
4572: PetcCall(SNESGetFunction(snes,&f,NULL,NULL));
4573: PetscCall(SNESComputeFunction(snes,x,f));
4574: }
4575: PetscFunctionReturn(PETSC_SUCCESS);
4576: }
4577: .ve
4579: 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.
4581: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetJacobian()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRSetPostCheck()`,
4582: `SNESMonitorSet()`
4583: @*/
4584: PetscErrorCode SNESSetUpdate(SNES snes, SNESUpdateFn *func)
4585: {
4586: PetscFunctionBegin;
4588: snes->ops->update = func;
4589: PetscFunctionReturn(PETSC_SUCCESS);
4590: }
4592: /*@
4593: SNESConvergedReasonView - Displays the reason a `SNES` solve converged or diverged to a viewer
4595: Collective
4597: Input Parameters:
4598: + snes - iterative context obtained from `SNESCreate()`
4599: - viewer - the viewer to display the reason
4601: Options Database Keys:
4602: + -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4603: - -snes_converged_reason ::failed - only print reason and number of iterations when diverged
4605: Level: beginner
4607: Note:
4608: To change the format of the output call `PetscViewerPushFormat`(viewer,format) before this call. Use `PETSC_VIEWER_DEFAULT` for the default,
4609: use `PETSC_VIEWER_FAILED` to only display a reason if it fails.
4611: .seealso: [](ch_snes), `SNESConvergedReason`, `PetscViewer`, `SNES`,
4612: `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`, `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`,
4613: `SNESConvergedReasonViewFromOptions()`,
4614: `PetscViewerPushFormat()`, `PetscViewerPopFormat()`
4615: @*/
4616: PetscErrorCode SNESConvergedReasonView(SNES snes, PetscViewer viewer)
4617: {
4618: PetscViewerFormat format;
4619: PetscBool isAscii;
4621: PetscFunctionBegin;
4622: if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4623: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isAscii));
4624: if (isAscii) {
4625: PetscCall(PetscViewerGetFormat(viewer, &format));
4626: PetscCall(PetscViewerASCIIAddTab(viewer, ((PetscObject)snes)->tablevel + 1));
4627: if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4628: DM dm;
4629: Vec u;
4630: PetscDS prob;
4631: PetscInt Nf, f;
4632: PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4633: void **exactCtx;
4634: PetscReal error;
4636: PetscCall(SNESGetDM(snes, &dm));
4637: PetscCall(SNESGetSolution(snes, &u));
4638: PetscCall(DMGetDS(dm, &prob));
4639: PetscCall(PetscDSGetNumFields(prob, &Nf));
4640: PetscCall(PetscMalloc2(Nf, &exactSol, Nf, &exactCtx));
4641: for (f = 0; f < Nf; ++f) PetscCall(PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]));
4642: PetscCall(DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error));
4643: PetscCall(PetscFree2(exactSol, exactCtx));
4644: if (error < 1.0e-11) PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n"));
4645: else PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", (double)error));
4646: }
4647: if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4648: if (((PetscObject)snes)->prefix) {
4649: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve converged due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4650: } else {
4651: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve converged due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4652: }
4653: } else if (snes->reason <= 0) {
4654: if (((PetscObject)snes)->prefix) {
4655: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve did not converge due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4656: } else {
4657: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve did not converge due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4658: }
4659: }
4660: PetscCall(PetscViewerASCIISubtractTab(viewer, ((PetscObject)snes)->tablevel + 1));
4661: }
4662: PetscFunctionReturn(PETSC_SUCCESS);
4663: }
4665: /*@C
4666: SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4667: end of the nonlinear solver to display the convergence reason of the nonlinear solver.
4669: Logically Collective
4671: Input Parameters:
4672: + snes - the `SNES` context
4673: . f - the `SNESConvergedReason` view function
4674: . vctx - [optional] user-defined context for private data for the `SNESConvergedReason` view function (use `NULL` if no context is desired)
4675: - reasonviewdestroy - [optional] routine that frees the context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4677: Calling sequence of `f`:
4678: + snes - the `SNES` context
4679: - vctx - [optional] context for private data for the function
4681: Options Database Keys:
4682: + -snes_converged_reason - sets a default `SNESConvergedReasonView()`
4683: - -snes_converged_reason_view_cancel - cancels all converged reason viewers that have been hardwired into a code by
4684: calls to `SNESConvergedReasonViewSet()`, but does not cancel those set via the options database.
4686: Level: intermediate
4688: Note:
4689: Several different converged reason view routines may be set by calling
4690: `SNESConvergedReasonViewSet()` multiple times; all will be called in the
4691: order in which they were set.
4693: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESConvergedReason`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`, `SNESConvergedReasonViewCancel()`,
4694: `PetscCtxDestroyFn`
4695: @*/
4696: PetscErrorCode SNESConvergedReasonViewSet(SNES snes, PetscErrorCode (*f)(SNES snes, void *vctx), void *vctx, PetscCtxDestroyFn *reasonviewdestroy)
4697: {
4698: PetscInt i;
4699: PetscBool identical;
4701: PetscFunctionBegin;
4703: for (i = 0; i < snes->numberreasonviews; i++) {
4704: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))f, vctx, reasonviewdestroy, (PetscErrorCode (*)(void))snes->reasonview[i], snes->reasonviewcontext[i], snes->reasonviewdestroy[i], &identical));
4705: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4706: }
4707: PetscCheck(snes->numberreasonviews < MAXSNESREASONVIEWS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many SNES reasonview set");
4708: snes->reasonview[snes->numberreasonviews] = f;
4709: snes->reasonviewdestroy[snes->numberreasonviews] = reasonviewdestroy;
4710: snes->reasonviewcontext[snes->numberreasonviews++] = vctx;
4711: PetscFunctionReturn(PETSC_SUCCESS);
4712: }
4714: /*@
4715: SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a `SNESConvergedReason` is to be viewed at the end of `SNESSolve()`
4716: All the user-provided viewer routines set with `SNESConvergedReasonViewSet()` will be called, if they exist.
4718: Collective
4720: Input Parameter:
4721: . snes - the `SNES` object
4723: Level: advanced
4725: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESConvergedReasonViewSet()`, `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`,
4726: `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`
4727: @*/
4728: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4729: {
4730: static PetscBool incall = PETSC_FALSE;
4732: PetscFunctionBegin;
4733: if (incall) PetscFunctionReturn(PETSC_SUCCESS);
4734: incall = PETSC_TRUE;
4736: /* All user-provided viewers are called first, if they exist. */
4737: for (PetscInt i = 0; i < snes->numberreasonviews; i++) PetscCall((*snes->reasonview[i])(snes, snes->reasonviewcontext[i]));
4739: /* Call PETSc default routine if users ask for it */
4740: if (snes->convergedreasonviewer) {
4741: PetscCall(PetscViewerPushFormat(snes->convergedreasonviewer, snes->convergedreasonformat));
4742: PetscCall(SNESConvergedReasonView(snes, snes->convergedreasonviewer));
4743: PetscCall(PetscViewerPopFormat(snes->convergedreasonviewer));
4744: }
4745: incall = PETSC_FALSE;
4746: PetscFunctionReturn(PETSC_SUCCESS);
4747: }
4749: /*@
4750: SNESSolve - Solves a nonlinear system $F(x) = b $ associated with a `SNES` object
4752: Collective
4754: Input Parameters:
4755: + snes - the `SNES` context
4756: . b - the constant part of the equation $F(x) = b$, or `NULL` to use zero.
4757: - x - the solution vector.
4759: Level: beginner
4761: Note:
4762: The user should initialize the vector, `x`, with the initial guess
4763: for the nonlinear solve prior to calling `SNESSolve()` .
4765: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFunction()`, `SNESSetJacobian()`, `SNESSetGridSequence()`, `SNESGetSolution()`,
4766: `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRGetPreCheck()`, `SNESNewtonTRSetPostCheck()`, `SNESNewtonTRGetPostCheck()`,
4767: `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`
4768: @*/
4769: PetscErrorCode SNESSolve(SNES snes, Vec b, Vec x)
4770: {
4771: PetscBool flg;
4772: PetscInt grid;
4773: Vec xcreated = NULL;
4774: DM dm;
4776: PetscFunctionBegin;
4779: if (x) PetscCheckSameComm(snes, 1, x, 3);
4781: if (b) PetscCheckSameComm(snes, 1, b, 2);
4783: /* High level operations using the nonlinear solver */
4784: {
4785: PetscViewer viewer;
4786: PetscViewerFormat format;
4787: PetscInt num;
4788: PetscBool flg;
4789: static PetscBool incall = PETSC_FALSE;
4791: if (!incall) {
4792: /* Estimate the convergence rate of the discretization */
4793: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg));
4794: if (flg) {
4795: PetscConvEst conv;
4796: DM dm;
4797: PetscReal *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4798: PetscInt Nf;
4800: incall = PETSC_TRUE;
4801: PetscCall(SNESGetDM(snes, &dm));
4802: PetscCall(DMGetNumFields(dm, &Nf));
4803: PetscCall(PetscCalloc1(Nf, &alpha));
4804: PetscCall(PetscConvEstCreate(PetscObjectComm((PetscObject)snes), &conv));
4805: PetscCall(PetscConvEstSetSolver(conv, (PetscObject)snes));
4806: PetscCall(PetscConvEstSetFromOptions(conv));
4807: PetscCall(PetscConvEstSetUp(conv));
4808: PetscCall(PetscConvEstGetConvRate(conv, alpha));
4809: PetscCall(PetscViewerPushFormat(viewer, format));
4810: PetscCall(PetscConvEstRateView(conv, alpha, viewer));
4811: PetscCall(PetscViewerPopFormat(viewer));
4812: PetscCall(PetscViewerDestroy(&viewer));
4813: PetscCall(PetscConvEstDestroy(&conv));
4814: PetscCall(PetscFree(alpha));
4815: incall = PETSC_FALSE;
4816: }
4817: /* Adaptively refine the initial grid */
4818: num = 1;
4819: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_initial", &num, &flg));
4820: if (flg) {
4821: DMAdaptor adaptor;
4823: incall = PETSC_TRUE;
4824: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4825: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4826: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4827: PetscCall(DMAdaptorSetFromOptions(adaptor));
4828: PetscCall(DMAdaptorSetUp(adaptor));
4829: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x));
4830: PetscCall(DMAdaptorDestroy(&adaptor));
4831: incall = PETSC_FALSE;
4832: }
4833: /* Use grid sequencing to adapt */
4834: num = 0;
4835: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_sequence", &num, NULL));
4836: if (num) {
4837: DMAdaptor adaptor;
4838: const char *prefix;
4840: incall = PETSC_TRUE;
4841: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4842: PetscCall(SNESGetOptionsPrefix(snes, &prefix));
4843: PetscCall(DMAdaptorSetOptionsPrefix(adaptor, prefix));
4844: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4845: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4846: PetscCall(DMAdaptorSetFromOptions(adaptor));
4847: PetscCall(DMAdaptorSetUp(adaptor));
4848: PetscCall(PetscObjectViewFromOptions((PetscObject)adaptor, NULL, "-snes_adapt_view"));
4849: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x));
4850: PetscCall(DMAdaptorDestroy(&adaptor));
4851: incall = PETSC_FALSE;
4852: }
4853: }
4854: }
4855: if (!x) x = snes->vec_sol;
4856: if (!x) {
4857: PetscCall(SNESGetDM(snes, &dm));
4858: PetscCall(DMCreateGlobalVector(dm, &xcreated));
4859: x = xcreated;
4860: }
4861: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view_pre"));
4863: for (grid = 0; grid < snes->gridsequence; grid++) PetscCall(PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4864: for (grid = 0; grid < snes->gridsequence + 1; grid++) {
4865: /* set solution vector */
4866: if (!grid) PetscCall(PetscObjectReference((PetscObject)x));
4867: PetscCall(VecDestroy(&snes->vec_sol));
4868: snes->vec_sol = x;
4869: PetscCall(SNESGetDM(snes, &dm));
4871: /* set affine vector if provided */
4872: if (b) PetscCall(PetscObjectReference((PetscObject)b));
4873: PetscCall(VecDestroy(&snes->vec_rhs));
4874: snes->vec_rhs = b;
4876: 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");
4877: PetscCheck(snes->vec_func != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be function vector");
4878: PetscCheck(snes->vec_rhs != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be right-hand side vector");
4879: if (!snes->vec_sol_update /* && snes->vec_sol */) PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_sol_update));
4880: PetscCall(DMShellSetGlobalVector(dm, snes->vec_sol));
4881: PetscCall(SNESSetUp(snes));
4883: if (!grid) {
4884: if (snes->ops->computeinitialguess) PetscCallBack("SNES callback compute initial guess", (*snes->ops->computeinitialguess)(snes, snes->vec_sol, snes->initialguessP));
4885: }
4887: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4888: PetscCall(SNESResetCounters(snes));
4889: snes->reason = SNES_CONVERGED_ITERATING;
4890: PetscCall(PetscLogEventBegin(SNES_Solve, snes, 0, 0, 0));
4891: PetscUseTypeMethod(snes, solve);
4892: PetscCall(PetscLogEventEnd(SNES_Solve, snes, 0, 0, 0));
4893: PetscCheck(snes->reason, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Internal error, solver %s returned without setting converged reason", ((PetscObject)snes)->type_name);
4894: snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */
4896: if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4897: if (snes->lagpre_persist) snes->pre_iter += snes->iter;
4899: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_test_local_min", NULL, NULL, &flg));
4900: if (flg && !PetscPreLoadingOn) PetscCall(SNESTestLocalMin(snes));
4901: /* Call converged reason views. This may involve user-provided viewers as well */
4902: PetscCall(SNESConvergedReasonViewFromOptions(snes));
4904: if (snes->errorifnotconverged) PetscCheck(snes->reason >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_NOT_CONVERGED, "SNESSolve has not converged");
4905: if (snes->reason < 0) break;
4906: if (grid < snes->gridsequence) {
4907: DM fine;
4908: Vec xnew;
4909: Mat interp;
4911: PetscCall(DMRefine(snes->dm, PetscObjectComm((PetscObject)snes), &fine));
4912: PetscCheck(fine, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "DMRefine() did not perform any refinement, cannot continue grid sequencing");
4913: PetscCall(DMGetCoordinatesLocalSetUp(fine));
4914: PetscCall(DMCreateInterpolation(snes->dm, fine, &interp, NULL));
4915: PetscCall(DMCreateGlobalVector(fine, &xnew));
4916: PetscCall(MatInterpolate(interp, x, xnew));
4917: PetscCall(DMInterpolate(snes->dm, interp, fine));
4918: PetscCall(MatDestroy(&interp));
4919: x = xnew;
4921: PetscCall(SNESReset(snes));
4922: PetscCall(SNESSetDM(snes, fine));
4923: PetscCall(SNESResetFromOptions(snes));
4924: PetscCall(DMDestroy(&fine));
4925: PetscCall(PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4926: }
4927: }
4928: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view"));
4929: PetscCall(VecViewFromOptions(snes->vec_sol, (PetscObject)snes, "-snes_view_solution"));
4930: PetscCall(DMMonitor(snes->dm));
4931: PetscCall(SNESMonitorPauseFinal_Internal(snes));
4933: PetscCall(VecDestroy(&xcreated));
4934: PetscCall(PetscObjectSAWsBlock((PetscObject)snes));
4935: PetscFunctionReturn(PETSC_SUCCESS);
4936: }
4938: /* --------- Internal routines for SNES Package --------- */
4940: /*@
4941: SNESSetType - Sets the algorithm/method to be used to solve the nonlinear system with the given `SNES`
4943: Collective
4945: Input Parameters:
4946: + snes - the `SNES` context
4947: - type - a known method
4949: Options Database Key:
4950: . -snes_type <type> - Sets the method; use -help for a list
4951: of available methods (for instance, newtonls or newtontr)
4953: Level: intermediate
4955: Notes:
4956: See `SNESType` for available methods (for instance)
4957: + `SNESNEWTONLS` - Newton's method with line search
4958: (systems of nonlinear equations)
4959: - `SNESNEWTONTR` - Newton's method with trust region
4960: (systems of nonlinear equations)
4962: Normally, it is best to use the `SNESSetFromOptions()` command and then
4963: set the `SNES` solver type from the options database rather than by using
4964: this routine. Using the options database provides the user with
4965: maximum flexibility in evaluating the many nonlinear solvers.
4966: The `SNESSetType()` routine is provided for those situations where it
4967: is necessary to set the nonlinear solver independently of the command
4968: line or options database. This might be the case, for example, when
4969: the choice of solver changes during the execution of the program,
4970: and the user's application is taking responsibility for choosing the
4971: appropriate method.
4973: Developer Note:
4974: `SNESRegister()` adds a constructor for a new `SNESType` to `SNESList`, `SNESSetType()` locates
4975: the constructor in that list and calls it to create the specific object.
4977: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESType`, `SNESCreate()`, `SNESDestroy()`, `SNESGetType()`, `SNESSetFromOptions()`
4978: @*/
4979: PetscErrorCode SNESSetType(SNES snes, SNESType type)
4980: {
4981: PetscBool match;
4982: PetscErrorCode (*r)(SNES);
4984: PetscFunctionBegin;
4986: PetscAssertPointer(type, 2);
4988: PetscCall(PetscObjectTypeCompare((PetscObject)snes, type, &match));
4989: if (match) PetscFunctionReturn(PETSC_SUCCESS);
4991: PetscCall(PetscFunctionListFind(SNESList, type, &r));
4992: PetscCheck(r, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested SNES type %s", type);
4993: /* Destroy the previous private SNES context */
4994: PetscTryTypeMethod(snes, destroy);
4995: /* Reinitialize type-specific function pointers in SNESOps structure */
4996: snes->ops->reset = NULL;
4997: snes->ops->setup = NULL;
4998: snes->ops->solve = NULL;
4999: snes->ops->view = NULL;
5000: snes->ops->setfromoptions = NULL;
5001: snes->ops->destroy = NULL;
5003: /* It may happen the user has customized the line search before calling SNESSetType */
5004: if (((PetscObject)snes)->type_name) PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5006: /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
5007: snes->setupcalled = PETSC_FALSE;
5009: PetscCall(PetscObjectChangeTypeName((PetscObject)snes, type));
5010: PetscCall((*r)(snes));
5011: PetscFunctionReturn(PETSC_SUCCESS);
5012: }
5014: /*@
5015: SNESGetType - Gets the `SNES` method type and name (as a string).
5017: Not Collective
5019: Input Parameter:
5020: . snes - nonlinear solver context
5022: Output Parameter:
5023: . type - `SNES` method (a character string)
5025: Level: intermediate
5027: .seealso: [](ch_snes), `SNESSetType()`, `SNESType`, `SNESSetFromOptions()`, `SNES`
5028: @*/
5029: PetscErrorCode SNESGetType(SNES snes, SNESType *type)
5030: {
5031: PetscFunctionBegin;
5033: PetscAssertPointer(type, 2);
5034: *type = ((PetscObject)snes)->type_name;
5035: PetscFunctionReturn(PETSC_SUCCESS);
5036: }
5038: /*@
5039: SNESSetSolution - Sets the solution vector for use by the `SNES` routines.
5041: Logically Collective
5043: Input Parameters:
5044: + snes - the `SNES` context obtained from `SNESCreate()`
5045: - u - the solution vector
5047: Level: beginner
5049: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetSolution()`, `Vec`
5050: @*/
5051: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
5052: {
5053: DM dm;
5055: PetscFunctionBegin;
5058: PetscCall(PetscObjectReference((PetscObject)u));
5059: PetscCall(VecDestroy(&snes->vec_sol));
5061: snes->vec_sol = u;
5063: PetscCall(SNESGetDM(snes, &dm));
5064: PetscCall(DMShellSetGlobalVector(dm, u));
5065: PetscFunctionReturn(PETSC_SUCCESS);
5066: }
5068: /*@
5069: SNESGetSolution - Returns the vector where the approximate solution is
5070: stored. This is the fine grid solution when using `SNESSetGridSequence()`.
5072: Not Collective, but `x` is parallel if `snes` is parallel
5074: Input Parameter:
5075: . snes - the `SNES` context
5077: Output Parameter:
5078: . x - the solution
5080: Level: intermediate
5082: .seealso: [](ch_snes), `SNESSetSolution()`, `SNESSolve()`, `SNES`, `SNESGetSolutionUpdate()`, `SNESGetFunction()`
5083: @*/
5084: PetscErrorCode SNESGetSolution(SNES snes, Vec *x)
5085: {
5086: PetscFunctionBegin;
5088: PetscAssertPointer(x, 2);
5089: *x = snes->vec_sol;
5090: PetscFunctionReturn(PETSC_SUCCESS);
5091: }
5093: /*@
5094: SNESGetSolutionUpdate - Returns the vector where the solution update is
5095: stored.
5097: Not Collective, but `x` is parallel if `snes` is parallel
5099: Input Parameter:
5100: . snes - the `SNES` context
5102: Output Parameter:
5103: . x - the solution update
5105: Level: advanced
5107: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`
5108: @*/
5109: PetscErrorCode SNESGetSolutionUpdate(SNES snes, Vec *x)
5110: {
5111: PetscFunctionBegin;
5113: PetscAssertPointer(x, 2);
5114: *x = snes->vec_sol_update;
5115: PetscFunctionReturn(PETSC_SUCCESS);
5116: }
5118: /*@C
5119: SNESGetFunction - Returns the function that defines the nonlinear system set with `SNESSetFunction()`
5121: Not Collective, but `r` is parallel if `snes` is parallel. Collective if `r` is requested, but has not been created yet.
5123: Input Parameter:
5124: . snes - the `SNES` context
5126: Output Parameters:
5127: + r - the vector that is used to store residuals (or `NULL` if you don't want it)
5128: . f - the function (or `NULL` if you don't want it); for calling sequence see `SNESFunctionFn`
5129: - ctx - the function context (or `NULL` if you don't want it)
5131: Level: advanced
5133: Note:
5134: The vector `r` DOES NOT, in general, contain the current value of the `SNES` nonlinear function
5136: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetSolution()`, `SNESFunctionFn`
5137: @*/
5138: PetscErrorCode SNESGetFunction(SNES snes, Vec *r, SNESFunctionFn **f, void **ctx)
5139: {
5140: DM dm;
5142: PetscFunctionBegin;
5144: if (r) {
5145: if (!snes->vec_func) {
5146: if (snes->vec_rhs) {
5147: PetscCall(VecDuplicate(snes->vec_rhs, &snes->vec_func));
5148: } else if (snes->vec_sol) {
5149: PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_func));
5150: } else if (snes->dm) {
5151: PetscCall(DMCreateGlobalVector(snes->dm, &snes->vec_func));
5152: }
5153: }
5154: *r = snes->vec_func;
5155: }
5156: PetscCall(SNESGetDM(snes, &dm));
5157: PetscCall(DMSNESGetFunction(dm, f, ctx));
5158: PetscFunctionReturn(PETSC_SUCCESS);
5159: }
5161: /*@C
5162: SNESGetNGS - Returns the function and context set with `SNESSetNGS()`
5164: Input Parameter:
5165: . snes - the `SNES` context
5167: Output Parameters:
5168: + f - the function (or `NULL`) see `SNESNGSFn` for calling sequence
5169: - ctx - the function context (or `NULL`)
5171: Level: advanced
5173: .seealso: [](ch_snes), `SNESSetNGS()`, `SNESGetFunction()`, `SNESNGSFn`
5174: @*/
5175: PetscErrorCode SNESGetNGS(SNES snes, SNESNGSFn **f, void **ctx)
5176: {
5177: DM dm;
5179: PetscFunctionBegin;
5181: PetscCall(SNESGetDM(snes, &dm));
5182: PetscCall(DMSNESGetNGS(dm, f, ctx));
5183: PetscFunctionReturn(PETSC_SUCCESS);
5184: }
5186: /*@
5187: SNESSetOptionsPrefix - Sets the prefix used for searching for all
5188: `SNES` options in the database.
5190: Logically Collective
5192: Input Parameters:
5193: + snes - the `SNES` context
5194: - prefix - the prefix to prepend to all option names
5196: Level: advanced
5198: Note:
5199: A hyphen (-) must NOT be given at the beginning of the prefix name.
5200: The first character of all runtime options is AUTOMATICALLY the hyphen.
5202: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESAppendOptionsPrefix()`
5203: @*/
5204: PetscErrorCode SNESSetOptionsPrefix(SNES snes, const char prefix[])
5205: {
5206: PetscFunctionBegin;
5208: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes, prefix));
5209: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5210: if (snes->linesearch) {
5211: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5212: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch, prefix));
5213: }
5214: PetscCall(KSPSetOptionsPrefix(snes->ksp, prefix));
5215: PetscFunctionReturn(PETSC_SUCCESS);
5216: }
5218: /*@
5219: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
5220: `SNES` options in the database.
5222: Logically Collective
5224: Input Parameters:
5225: + snes - the `SNES` context
5226: - prefix - the prefix to prepend to all option names
5228: Level: advanced
5230: Note:
5231: A hyphen (-) must NOT be given at the beginning of the prefix name.
5232: The first character of all runtime options is AUTOMATICALLY the hyphen.
5234: .seealso: [](ch_snes), `SNESGetOptionsPrefix()`, `SNESSetOptionsPrefix()`
5235: @*/
5236: PetscErrorCode SNESAppendOptionsPrefix(SNES snes, const char prefix[])
5237: {
5238: PetscFunctionBegin;
5240: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes, prefix));
5241: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5242: if (snes->linesearch) {
5243: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5244: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch, prefix));
5245: }
5246: PetscCall(KSPAppendOptionsPrefix(snes->ksp, prefix));
5247: PetscFunctionReturn(PETSC_SUCCESS);
5248: }
5250: /*@
5251: SNESGetOptionsPrefix - Gets the prefix used for searching for all
5252: `SNES` options in the database.
5254: Not Collective
5256: Input Parameter:
5257: . snes - the `SNES` context
5259: Output Parameter:
5260: . prefix - pointer to the prefix string used
5262: Level: advanced
5264: .seealso: [](ch_snes), `SNES`, `SNESSetOptionsPrefix()`, `SNESAppendOptionsPrefix()`
5265: @*/
5266: PetscErrorCode SNESGetOptionsPrefix(SNES snes, const char *prefix[])
5267: {
5268: PetscFunctionBegin;
5270: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, prefix));
5271: PetscFunctionReturn(PETSC_SUCCESS);
5272: }
5274: /*@C
5275: SNESRegister - Adds a method to the nonlinear solver package.
5277: Not Collective
5279: Input Parameters:
5280: + sname - name of a new user-defined solver
5281: - function - routine to create method context
5283: Level: advanced
5285: Note:
5286: `SNESRegister()` may be called multiple times to add several user-defined solvers.
5288: Example Usage:
5289: .vb
5290: SNESRegister("my_solver", MySolverCreate);
5291: .ve
5293: Then, your solver can be chosen with the procedural interface via
5294: .vb
5295: SNESSetType(snes, "my_solver")
5296: .ve
5297: or at runtime via the option
5298: .vb
5299: -snes_type my_solver
5300: .ve
5302: .seealso: [](ch_snes), `SNESRegisterAll()`, `SNESRegisterDestroy()`
5303: @*/
5304: PetscErrorCode SNESRegister(const char sname[], PetscErrorCode (*function)(SNES))
5305: {
5306: PetscFunctionBegin;
5307: PetscCall(SNESInitializePackage());
5308: PetscCall(PetscFunctionListAdd(&SNESList, sname, function));
5309: PetscFunctionReturn(PETSC_SUCCESS);
5310: }
5312: PetscErrorCode SNESTestLocalMin(SNES snes)
5313: {
5314: PetscInt N, i, j;
5315: Vec u, uh, fh;
5316: PetscScalar value;
5317: PetscReal norm;
5319: PetscFunctionBegin;
5320: PetscCall(SNESGetSolution(snes, &u));
5321: PetscCall(VecDuplicate(u, &uh));
5322: PetscCall(VecDuplicate(u, &fh));
5324: /* currently only works for sequential */
5325: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "Testing FormFunction() for local min\n"));
5326: PetscCall(VecGetSize(u, &N));
5327: for (i = 0; i < N; i++) {
5328: PetscCall(VecCopy(u, uh));
5329: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "i = %" PetscInt_FMT "\n", i));
5330: for (j = -10; j < 11; j++) {
5331: value = PetscSign(j) * PetscExpReal(PetscAbs(j) - 10.0);
5332: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5333: PetscCall(SNESComputeFunction(snes, uh, fh));
5334: PetscCall(VecNorm(fh, NORM_2, &norm));
5335: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), " j norm %" PetscInt_FMT " %18.16e\n", j, (double)norm));
5336: value = -value;
5337: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5338: }
5339: }
5340: PetscCall(VecDestroy(&uh));
5341: PetscCall(VecDestroy(&fh));
5342: PetscFunctionReturn(PETSC_SUCCESS);
5343: }
5345: /*@
5346: SNESKSPSetUseEW - Sets `SNES` to the use Eisenstat-Walker method for
5347: computing relative tolerance for linear solvers within an inexact
5348: Newton method.
5350: Logically Collective
5352: Input Parameters:
5353: + snes - `SNES` context
5354: - flag - `PETSC_TRUE` or `PETSC_FALSE`
5356: Options Database Keys:
5357: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5358: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
5359: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5360: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5361: . -snes_ksp_ew_gamma <gamma> - Sets gamma
5362: . -snes_ksp_ew_alpha <alpha> - Sets alpha
5363: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5364: - -snes_ksp_ew_threshold <threshold> - Sets threshold
5366: Level: advanced
5368: Note:
5369: The default is to use a constant relative tolerance for
5370: the inner linear solvers. Alternatively, one can use the
5371: Eisenstat-Walker method {cite}`ew96`, where the relative convergence tolerance
5372: is reset at each Newton iteration according progress of the nonlinear
5373: solver.
5375: .seealso: [](ch_snes), `KSP`, `SNES`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5376: @*/
5377: PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)
5378: {
5379: PetscFunctionBegin;
5382: snes->ksp_ewconv = flag;
5383: PetscFunctionReturn(PETSC_SUCCESS);
5384: }
5386: /*@
5387: SNESKSPGetUseEW - Gets if `SNES` is using Eisenstat-Walker method
5388: for computing relative tolerance for linear solvers within an
5389: inexact Newton method.
5391: Not Collective
5393: Input Parameter:
5394: . snes - `SNES` context
5396: Output Parameter:
5397: . flag - `PETSC_TRUE` or `PETSC_FALSE`
5399: Level: advanced
5401: .seealso: [](ch_snes), `SNESKSPSetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5402: @*/
5403: PetscErrorCode SNESKSPGetUseEW(SNES snes, PetscBool *flag)
5404: {
5405: PetscFunctionBegin;
5407: PetscAssertPointer(flag, 2);
5408: *flag = snes->ksp_ewconv;
5409: PetscFunctionReturn(PETSC_SUCCESS);
5410: }
5412: /*@
5413: SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5414: convergence criteria for the linear solvers within an inexact
5415: Newton method.
5417: Logically Collective
5419: Input Parameters:
5420: + snes - `SNES` context
5421: . version - version 1, 2 (default is 2), 3 or 4
5422: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5423: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5424: . gamma - multiplicative factor for version 2 rtol computation
5425: (0 <= gamma2 <= 1)
5426: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5427: . alpha2 - power for safeguard
5428: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5430: Level: advanced
5432: Notes:
5433: Version 3 was contributed by Luis Chacon, June 2006.
5435: Use `PETSC_CURRENT` to retain the default for any of the parameters.
5437: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`
5438: @*/
5439: PetscErrorCode SNESKSPSetParametersEW(SNES snes, PetscInt version, PetscReal rtol_0, PetscReal rtol_max, PetscReal gamma, PetscReal alpha, PetscReal alpha2, PetscReal threshold)
5440: {
5441: SNESKSPEW *kctx;
5443: PetscFunctionBegin;
5445: kctx = (SNESKSPEW *)snes->kspconvctx;
5446: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5455: if (version != PETSC_CURRENT) kctx->version = version;
5456: if (rtol_0 != (PetscReal)PETSC_CURRENT) kctx->rtol_0 = rtol_0;
5457: if (rtol_max != (PetscReal)PETSC_CURRENT) kctx->rtol_max = rtol_max;
5458: if (gamma != (PetscReal)PETSC_CURRENT) kctx->gamma = gamma;
5459: if (alpha != (PetscReal)PETSC_CURRENT) kctx->alpha = alpha;
5460: if (alpha2 != (PetscReal)PETSC_CURRENT) kctx->alpha2 = alpha2;
5461: if (threshold != (PetscReal)PETSC_CURRENT) kctx->threshold = threshold;
5463: 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);
5464: 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);
5465: 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);
5466: 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);
5467: 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);
5468: 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);
5469: PetscFunctionReturn(PETSC_SUCCESS);
5470: }
5472: /*@
5473: SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5474: convergence criteria for the linear solvers within an inexact
5475: Newton method.
5477: Not Collective
5479: Input Parameter:
5480: . snes - `SNES` context
5482: Output Parameters:
5483: + version - version 1, 2 (default is 2), 3 or 4
5484: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5485: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5486: . gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5487: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5488: . alpha2 - power for safeguard
5489: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5491: Level: advanced
5493: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPSetParametersEW()`
5494: @*/
5495: PetscErrorCode SNESKSPGetParametersEW(SNES snes, PetscInt *version, PetscReal *rtol_0, PetscReal *rtol_max, PetscReal *gamma, PetscReal *alpha, PetscReal *alpha2, PetscReal *threshold)
5496: {
5497: SNESKSPEW *kctx;
5499: PetscFunctionBegin;
5501: kctx = (SNESKSPEW *)snes->kspconvctx;
5502: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5503: if (version) *version = kctx->version;
5504: if (rtol_0) *rtol_0 = kctx->rtol_0;
5505: if (rtol_max) *rtol_max = kctx->rtol_max;
5506: if (gamma) *gamma = kctx->gamma;
5507: if (alpha) *alpha = kctx->alpha;
5508: if (alpha2) *alpha2 = kctx->alpha2;
5509: if (threshold) *threshold = kctx->threshold;
5510: PetscFunctionReturn(PETSC_SUCCESS);
5511: }
5513: PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5514: {
5515: SNES snes = (SNES)ctx;
5516: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5517: PetscReal rtol = PETSC_CURRENT, stol;
5519: PetscFunctionBegin;
5520: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5521: if (!snes->iter) {
5522: rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5523: PetscCall(VecNorm(snes->vec_func, NORM_2, &kctx->norm_first));
5524: } else {
5525: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1-4 are supported: %" PetscInt_FMT, kctx->version);
5526: if (kctx->version == 1) {
5527: rtol = PetscAbsReal(snes->norm - kctx->lresid_last) / kctx->norm_last;
5528: stol = PetscPowReal(kctx->rtol_last, kctx->alpha2);
5529: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5530: } else if (kctx->version == 2) {
5531: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5532: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5533: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5534: } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5535: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5536: /* safeguard: avoid sharp decrease of rtol */
5537: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5538: stol = PetscMax(rtol, stol);
5539: rtol = PetscMin(kctx->rtol_0, stol);
5540: /* safeguard: avoid oversolving */
5541: stol = kctx->gamma * (kctx->norm_first * snes->rtol) / snes->norm;
5542: stol = PetscMax(rtol, stol);
5543: rtol = PetscMin(kctx->rtol_0, stol);
5544: } else /* if (kctx->version == 4) */ {
5545: /* H.-B. An et al. Journal of Computational and Applied Mathematics 200 (2007) 47-60 */
5546: PetscReal ared = PetscAbsReal(kctx->norm_last - snes->norm);
5547: PetscReal pred = PetscAbsReal(kctx->norm_last - kctx->lresid_last);
5548: PetscReal rk = ared / pred;
5549: if (rk < kctx->v4_p1) rtol = 1. - 2. * kctx->v4_p1;
5550: else if (rk < kctx->v4_p2) rtol = kctx->rtol_last;
5551: else if (rk < kctx->v4_p3) rtol = kctx->v4_m1 * kctx->rtol_last;
5552: else rtol = kctx->v4_m2 * kctx->rtol_last;
5554: 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;
5555: kctx->rtol_last_2 = kctx->rtol_last;
5556: kctx->rk_last_2 = kctx->rk_last;
5557: kctx->rk_last = rk;
5558: }
5559: }
5560: /* safeguard: avoid rtol greater than rtol_max */
5561: rtol = PetscMin(rtol, kctx->rtol_max);
5562: PetscCall(KSPSetTolerances(ksp, rtol, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT));
5563: PetscCall(PetscInfo(snes, "iter %" PetscInt_FMT ", Eisenstat-Walker (version %" PetscInt_FMT ") KSP rtol=%g\n", snes->iter, kctx->version, (double)rtol));
5564: PetscFunctionReturn(PETSC_SUCCESS);
5565: }
5567: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5568: {
5569: SNES snes = (SNES)ctx;
5570: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5571: PCSide pcside;
5572: Vec lres;
5574: PetscFunctionBegin;
5575: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5576: PetscCall(KSPGetTolerances(ksp, &kctx->rtol_last, NULL, NULL, NULL));
5577: kctx->norm_last = snes->norm;
5578: if (kctx->version == 1 || kctx->version == 4) {
5579: PC pc;
5580: PetscBool getRes;
5582: PetscCall(KSPGetPC(ksp, &pc));
5583: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCNONE, &getRes));
5584: if (!getRes) {
5585: KSPNormType normtype;
5587: PetscCall(KSPGetNormType(ksp, &normtype));
5588: getRes = (PetscBool)(normtype == KSP_NORM_UNPRECONDITIONED);
5589: }
5590: PetscCall(KSPGetPCSide(ksp, &pcside));
5591: if (pcside == PC_RIGHT || getRes) { /* KSP residual is true linear residual */
5592: PetscCall(KSPGetResidualNorm(ksp, &kctx->lresid_last));
5593: } else {
5594: /* KSP residual is preconditioned residual */
5595: /* compute true linear residual norm */
5596: Mat J;
5597: PetscCall(KSPGetOperators(ksp, &J, NULL));
5598: PetscCall(VecDuplicate(b, &lres));
5599: PetscCall(MatMult(J, x, lres));
5600: PetscCall(VecAYPX(lres, -1.0, b));
5601: PetscCall(VecNorm(lres, NORM_2, &kctx->lresid_last));
5602: PetscCall(VecDestroy(&lres));
5603: }
5604: }
5605: PetscFunctionReturn(PETSC_SUCCESS);
5606: }
5608: /*@
5609: SNESGetKSP - Returns the `KSP` context for a `SNES` solver.
5611: Not Collective, but if `snes` is parallel, then `ksp` is parallel
5613: Input Parameter:
5614: . snes - the `SNES` context
5616: Output Parameter:
5617: . ksp - the `KSP` context
5619: Level: beginner
5621: Notes:
5622: The user can then directly manipulate the `KSP` context to set various
5623: options, etc. Likewise, the user can then extract and manipulate the
5624: `PC` contexts as well.
5626: 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.
5628: .seealso: [](ch_snes), `SNES`, `KSP`, `PC`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
5629: @*/
5630: PetscErrorCode SNESGetKSP(SNES snes, KSP *ksp)
5631: {
5632: PetscFunctionBegin;
5634: PetscAssertPointer(ksp, 2);
5636: if (!snes->ksp) {
5637: PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes), &snes->ksp));
5638: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->ksp, (PetscObject)snes, 1));
5640: PetscCall(KSPSetPreSolve(snes->ksp, KSPPreSolve_SNESEW, snes));
5641: PetscCall(KSPSetPostSolve(snes->ksp, KSPPostSolve_SNESEW, snes));
5643: PetscCall(KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes));
5644: PetscCall(PetscObjectSetOptions((PetscObject)snes->ksp, ((PetscObject)snes)->options));
5645: }
5646: *ksp = snes->ksp;
5647: PetscFunctionReturn(PETSC_SUCCESS);
5648: }
5650: #include <petsc/private/dmimpl.h>
5651: /*@
5652: SNESSetDM - Sets the `DM` that may be used by some `SNES` nonlinear solvers or their underlying preconditioners
5654: Logically Collective
5656: Input Parameters:
5657: + snes - the nonlinear solver context
5658: - dm - the `DM`, cannot be `NULL`
5660: Level: intermediate
5662: Note:
5663: A `DM` can only be used for solving one problem at a time because information about the problem is stored on the `DM`,
5664: even when not using interfaces like `DMSNESSetFunction()`. Use `DMClone()` to get a distinct `DM` when solving different
5665: problems using the same function space.
5667: .seealso: [](ch_snes), `DM`, `SNES`, `SNESGetDM()`, `KSPSetDM()`, `KSPGetDM()`
5668: @*/
5669: PetscErrorCode SNESSetDM(SNES snes, DM dm)
5670: {
5671: KSP ksp;
5672: DMSNES sdm;
5674: PetscFunctionBegin;
5677: PetscCall(PetscObjectReference((PetscObject)dm));
5678: if (snes->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
5679: if (snes->dm->dmsnes && !dm->dmsnes) {
5680: PetscCall(DMCopyDMSNES(snes->dm, dm));
5681: PetscCall(DMGetDMSNES(snes->dm, &sdm));
5682: if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5683: }
5684: PetscCall(DMCoarsenHookRemove(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
5685: PetscCall(DMDestroy(&snes->dm));
5686: }
5687: snes->dm = dm;
5688: snes->dmAuto = PETSC_FALSE;
5690: PetscCall(SNESGetKSP(snes, &ksp));
5691: PetscCall(KSPSetDM(ksp, dm));
5692: PetscCall(KSPSetDMActive(ksp, PETSC_FALSE));
5693: if (snes->npc) {
5694: PetscCall(SNESSetDM(snes->npc, snes->dm));
5695: PetscCall(SNESSetNPCSide(snes, snes->npcside));
5696: }
5697: PetscFunctionReturn(PETSC_SUCCESS);
5698: }
5700: /*@
5701: SNESGetDM - Gets the `DM` that may be used by some `SNES` nonlinear solvers/preconditioners
5703: Not Collective but `dm` obtained is parallel on `snes`
5705: Input Parameter:
5706: . snes - the `SNES` context
5708: Output Parameter:
5709: . dm - the `DM`
5711: Level: intermediate
5713: .seealso: [](ch_snes), `DM`, `SNES`, `SNESSetDM()`, `KSPSetDM()`, `KSPGetDM()`
5714: @*/
5715: PetscErrorCode SNESGetDM(SNES snes, DM *dm)
5716: {
5717: PetscFunctionBegin;
5719: if (!snes->dm) {
5720: PetscCall(DMShellCreate(PetscObjectComm((PetscObject)snes), &snes->dm));
5721: snes->dmAuto = PETSC_TRUE;
5722: }
5723: *dm = snes->dm;
5724: PetscFunctionReturn(PETSC_SUCCESS);
5725: }
5727: /*@
5728: SNESSetNPC - Sets the nonlinear preconditioner to be used.
5730: Collective
5732: Input Parameters:
5733: + snes - iterative context obtained from `SNESCreate()`
5734: - npc - the `SNES` nonlinear preconditioner object
5736: Options Database Key:
5737: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5739: Level: developer
5741: Notes:
5742: This is rarely used, rather use `SNESGetNPC()` to retrieve the preconditioner and configure it using the API.
5744: Only some `SNESType` can use a nonlinear preconditioner
5746: .seealso: [](ch_snes), `SNES`, `SNESNGS`, `SNESFAS`, `SNESGetNPC()`, `SNESHasNPC()`
5747: @*/
5748: PetscErrorCode SNESSetNPC(SNES snes, SNES npc)
5749: {
5750: PetscFunctionBegin;
5753: PetscCheckSameComm(snes, 1, npc, 2);
5754: PetscCall(PetscObjectReference((PetscObject)npc));
5755: PetscCall(SNESDestroy(&snes->npc));
5756: snes->npc = npc;
5757: PetscFunctionReturn(PETSC_SUCCESS);
5758: }
5760: /*@
5761: SNESGetNPC - Gets a nonlinear preconditioning solver SNES` to be used to precondition the original nonlinear solver.
5763: Not Collective; but any changes to the obtained the `pc` object must be applied collectively
5765: Input Parameter:
5766: . snes - iterative context obtained from `SNESCreate()`
5768: Output Parameter:
5769: . pc - the `SNES` preconditioner context
5771: Options Database Key:
5772: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5774: Level: advanced
5776: Notes:
5777: If a `SNES` was previously set with `SNESSetNPC()` then that value is returned, otherwise a new `SNES` object is created that will
5778: be used as the nonlinear preconditioner for the current `SNES`.
5780: The (preconditioner) `SNES` returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5781: `SNES`. These may be overwritten if needed.
5783: Use the options database prefixes `-npc_snes`, `-npc_ksp`, etc., to control the configuration of the nonlinear preconditioner
5785: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESHasNPC()`, `SNES`, `SNESCreate()`
5786: @*/
5787: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5788: {
5789: const char *optionsprefix;
5791: PetscFunctionBegin;
5793: PetscAssertPointer(pc, 2);
5794: if (!snes->npc) {
5795: void *ctx;
5797: PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &snes->npc));
5798: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->npc, (PetscObject)snes, 1));
5799: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5800: PetscCall(SNESSetOptionsPrefix(snes->npc, optionsprefix));
5801: PetscCall(SNESAppendOptionsPrefix(snes->npc, "npc_"));
5802: if (snes->ops->usercompute) {
5803: PetscCall(SNESSetComputeApplicationContext(snes, snes->ops->usercompute, snes->ops->ctxdestroy));
5804: } else {
5805: PetscCall(SNESGetApplicationContext(snes, &ctx));
5806: PetscCall(SNESSetApplicationContext(snes->npc, ctx));
5807: }
5808: PetscCall(SNESSetCountersReset(snes->npc, PETSC_FALSE));
5809: }
5810: *pc = snes->npc;
5811: PetscFunctionReturn(PETSC_SUCCESS);
5812: }
5814: /*@
5815: SNESHasNPC - Returns whether a nonlinear preconditioner is associated with the given `SNES`
5817: Not Collective
5819: Input Parameter:
5820: . snes - iterative context obtained from `SNESCreate()`
5822: Output Parameter:
5823: . has_npc - whether the `SNES` has a nonlinear preconditioner or not
5825: Level: developer
5827: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESGetNPC()`
5828: @*/
5829: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5830: {
5831: PetscFunctionBegin;
5833: PetscAssertPointer(has_npc, 2);
5834: *has_npc = snes->npc ? PETSC_TRUE : PETSC_FALSE;
5835: PetscFunctionReturn(PETSC_SUCCESS);
5836: }
5838: /*@
5839: SNESSetNPCSide - Sets the nonlinear preconditioning side used by the nonlinear preconditioner inside `SNES`.
5841: Logically Collective
5843: Input Parameter:
5844: . snes - iterative context obtained from `SNESCreate()`
5846: Output Parameter:
5847: . side - the preconditioning side, where side is one of
5848: .vb
5849: PC_LEFT - left preconditioning
5850: PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5851: .ve
5853: Options Database Key:
5854: . -snes_npc_side <right,left> - nonlinear preconditioner side
5856: Level: intermediate
5858: Note:
5859: `SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.
5861: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESNRICHARDSON`, `SNESNCG`, `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5862: @*/
5863: PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
5864: {
5865: PetscFunctionBegin;
5868: if (side == PC_SIDE_DEFAULT) side = PC_RIGHT;
5869: PetscCheck((side == PC_LEFT) || (side == PC_RIGHT), PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Only PC_LEFT and PC_RIGHT are supported");
5870: snes->npcside = side;
5871: PetscFunctionReturn(PETSC_SUCCESS);
5872: }
5874: /*@
5875: SNESGetNPCSide - Gets the preconditioning side used by the nonlinear preconditioner inside `SNES`.
5877: Not Collective
5879: Input Parameter:
5880: . snes - iterative context obtained from `SNESCreate()`
5882: Output Parameter:
5883: . side - the preconditioning side, where side is one of
5884: .vb
5885: `PC_LEFT` - left preconditioning
5886: `PC_RIGHT` - right preconditioning (default for most nonlinear solvers)
5887: .ve
5889: Level: intermediate
5891: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESSetNPCSide()`, `KSPGetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5892: @*/
5893: PetscErrorCode SNESGetNPCSide(SNES snes, PCSide *side)
5894: {
5895: PetscFunctionBegin;
5897: PetscAssertPointer(side, 2);
5898: *side = snes->npcside;
5899: PetscFunctionReturn(PETSC_SUCCESS);
5900: }
5902: /*@
5903: SNESSetLineSearch - Sets the `SNESLineSearch` to be used for a given `SNES`
5905: Collective
5907: Input Parameters:
5908: + snes - iterative context obtained from `SNESCreate()`
5909: - linesearch - the linesearch object
5911: Level: developer
5913: Note:
5914: This is almost never used, rather one uses `SNESGetLineSearch()` to retrieve the line search and set options on it
5915: to configure it using the API).
5917: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`
5918: @*/
5919: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5920: {
5921: PetscFunctionBegin;
5924: PetscCheckSameComm(snes, 1, linesearch, 2);
5925: PetscCall(PetscObjectReference((PetscObject)linesearch));
5926: PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5928: snes->linesearch = linesearch;
5929: PetscFunctionReturn(PETSC_SUCCESS);
5930: }
5932: /*@
5933: SNESGetLineSearch - Returns the line search associated with the `SNES`.
5935: Not Collective
5937: Input Parameter:
5938: . snes - iterative context obtained from `SNESCreate()`
5940: Output Parameter:
5941: . linesearch - linesearch context
5943: Level: beginner
5945: Notes:
5946: It creates a default line search instance which can be configured as needed in case it has not been already set with `SNESSetLineSearch()`.
5948: You can also use the options database keys `-snes_linesearch_*` to configure the line search. See `SNESLineSearchSetFromOptions()` for the possible options.
5950: .seealso: [](ch_snes), `SNESLineSearch`, `SNESSetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`
5951: @*/
5952: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5953: {
5954: const char *optionsprefix;
5956: PetscFunctionBegin;
5958: PetscAssertPointer(linesearch, 2);
5959: if (!snes->linesearch) {
5960: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5961: PetscCall(SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch));
5962: PetscCall(SNESLineSearchSetSNES(snes->linesearch, snes));
5963: PetscCall(SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix));
5964: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->linesearch, (PetscObject)snes, 1));
5965: }
5966: *linesearch = snes->linesearch;
5967: PetscFunctionReturn(PETSC_SUCCESS);
5968: }