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: Not Collective
122: Input Parameter:
123: . snes - the `SNES` context
125: Level: advanced
127: Notes:
128: This does not need to be called by all processes in the `SNES` MPI communicator.
130: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
132: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
134: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
135: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
137: You can call `SNESSetJacobianDomainError()` during a Jacobian computation to indicate the proposed solution is not in the domain.
139: Developer Note:
140: This value is used by `SNESCheckFunctionNorm()` to determine if the `SNESConvergedReason` is set to `SNES_DIVERGED_FUNCTION_DOMAIN`
142: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetJacobianDomainError()`, `SNESVISetVariableBounds()`,
143: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`,
144: `SNES_DIVERGED_FUNCTION_DOMAIN`
145: @*/
146: PetscErrorCode SNESSetFunctionDomainError(SNES snes)
147: {
148: PetscFunctionBegin;
150: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates input vector is not in the function domain");
151: snes->domainerror = PETSC_TRUE;
152: PetscFunctionReturn(PETSC_SUCCESS);
153: }
155: /*@
156: SNESSetJacobianDomainError - tells `SNES` that the function you provided to `SNESSetJacobian()` at the proposed step. For example there is a negative element transformation.
158: Logically Collective
160: Input Parameter:
161: . snes - the `SNES` context
163: Level: advanced
165: Notes:
166: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
168: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
170: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
171: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
173: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESVISetVariableBounds()`,
174: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`
175: @*/
176: PetscErrorCode SNESSetJacobianDomainError(SNES snes)
177: {
178: PetscFunctionBegin;
180: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates computeJacobian does not make sense");
181: snes->jacobiandomainerror = PETSC_TRUE;
182: PetscFunctionReturn(PETSC_SUCCESS);
183: }
185: /*@
186: SNESSetCheckJacobianDomainError - tells `SNESSolve()` whether to check if the user called `SNESSetJacobianDomainError()` Jacobian domain error after
187: 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.
189: Logically Collective
191: Input Parameters:
192: + snes - the `SNES` context
193: - flg - indicates if or not to check Jacobian domain error after each Jacobian evaluation
195: Level: advanced
197: Note:
198: Checks require one extra parallel synchronization for each Jacobian evaluation
200: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESGetCheckJacobianDomainError()`
201: @*/
202: PetscErrorCode SNESSetCheckJacobianDomainError(SNES snes, PetscBool flg)
203: {
204: PetscFunctionBegin;
206: snes->checkjacdomainerror = flg;
207: PetscFunctionReturn(PETSC_SUCCESS);
208: }
210: /*@
211: SNESGetCheckJacobianDomainError - Get an indicator whether or not `SNES` is checking Jacobian domain errors after each Jacobian evaluation.
213: Logically Collective
215: Input Parameter:
216: . snes - the `SNES` context
218: Output Parameter:
219: . flg - `PETSC_FALSE` indicates that it is not checking Jacobian domain errors after each Jacobian evaluation
221: Level: advanced
223: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESSetCheckJacobianDomainError()`
224: @*/
225: PetscErrorCode SNESGetCheckJacobianDomainError(SNES snes, PetscBool *flg)
226: {
227: PetscFunctionBegin;
229: PetscAssertPointer(flg, 2);
230: *flg = snes->checkjacdomainerror;
231: PetscFunctionReturn(PETSC_SUCCESS);
232: }
234: /*@
235: SNESGetFunctionDomainError - Gets the status of the domain error after a call to `SNESComputeFunction()`
237: Not Collective, different MPI processes may return different values
239: Input Parameter:
240: . snes - the `SNES` context
242: Output Parameter:
243: . domainerror - Set to `PETSC_TRUE` if there's a domain error; `PETSC_FALSE` otherwise.
245: Level: developer
247: Notes:
248: The value will only be true on those MPI processes that called `SNESSetFunctionDomainError()`
250: The value is reset to `PETSC_FALSE` when `SNESCheckFunctionNorm()` is called.
252: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`
253: @*/
254: PetscErrorCode SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
255: {
256: PetscFunctionBegin;
258: PetscAssertPointer(domainerror, 2);
259: *domainerror = snes->domainerror;
260: PetscFunctionReturn(PETSC_SUCCESS);
261: }
263: /*@
264: SNESGetJacobianDomainError - Gets the status of the Jacobian domain error after a call to `SNESComputeJacobian()`
266: Not Collective, different MPI processes may return different values
268: Input Parameter:
269: . snes - the `SNES` context
271: Output Parameter:
272: . domainerror - Set to `PETSC_TRUE` if there's a Jacobian domain error; `PETSC_FALSE` otherwise.
274: Level: advanced
276: Notes:
277: The value will only be true on those MPI processes that called `SNESSetJacobianDomainError()`
279: The value is reset to `PETSC_FALSE` when `SNESCheckJacobianDomainerror()` is called but only `SNESSetCheckJacobianDomainError()` was called
281: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`, `SNESGetFunctionDomainError()`
282: @*/
283: PetscErrorCode SNESGetJacobianDomainError(SNES snes, PetscBool *domainerror)
284: {
285: PetscFunctionBegin;
287: PetscAssertPointer(domainerror, 2);
288: *domainerror = snes->jacobiandomainerror;
289: PetscFunctionReturn(PETSC_SUCCESS);
290: }
292: /*@
293: SNESLoad - Loads a `SNES` that has been stored in `PETSCVIEWERBINARY` with `SNESView()`.
295: Collective
297: Input Parameters:
298: + snes - the newly loaded `SNES`, this needs to have been created with `SNESCreate()` or
299: some related function before a call to `SNESLoad()`.
300: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()`
302: Level: intermediate
304: Note:
305: The `SNESType` is determined by the data in the file, any type set into the `SNES` before this call is ignored.
307: .seealso: [](ch_snes), `SNES`, `PetscViewer`, `SNESCreate()`, `SNESType`, `PetscViewerBinaryOpen()`, `SNESView()`, `MatLoad()`, `VecLoad()`
308: @*/
309: PetscErrorCode SNESLoad(SNES snes, PetscViewer viewer)
310: {
311: PetscBool isbinary;
312: PetscInt classid;
313: char type[256];
314: KSP ksp;
315: DM dm;
316: DMSNES dmsnes;
318: PetscFunctionBegin;
321: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
322: PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
324: PetscCall(PetscViewerBinaryRead(viewer, &classid, 1, NULL, PETSC_INT));
325: PetscCheck(classid == SNES_FILE_CLASSID, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Not SNES next in file");
326: PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
327: PetscCall(SNESSetType(snes, type));
328: PetscTryTypeMethod(snes, load, viewer);
329: PetscCall(SNESGetDM(snes, &dm));
330: PetscCall(DMGetDMSNES(dm, &dmsnes));
331: PetscCall(DMSNESLoad(dmsnes, viewer));
332: PetscCall(SNESGetKSP(snes, &ksp));
333: PetscCall(KSPLoad(ksp, viewer));
334: PetscFunctionReturn(PETSC_SUCCESS);
335: }
337: #include <petscdraw.h>
338: #if defined(PETSC_HAVE_SAWS)
339: #include <petscviewersaws.h>
340: #endif
342: /*@
343: SNESViewFromOptions - View a `SNES` based on values in the options database
345: Collective
347: Input Parameters:
348: + A - the `SNES` context
349: . obj - Optional object that provides the options prefix for the checks
350: - name - command line option
352: Level: intermediate
354: .seealso: [](ch_snes), `SNES`, `SNESView`, `PetscObjectViewFromOptions()`, `SNESCreate()`
355: @*/
356: PetscErrorCode SNESViewFromOptions(SNES A, PetscObject obj, const char name[])
357: {
358: PetscFunctionBegin;
360: PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
361: PetscFunctionReturn(PETSC_SUCCESS);
362: }
364: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES, Vec, Mat, Mat, void *);
366: /*@
367: SNESView - Prints or visualizes the `SNES` data structure.
369: Collective
371: Input Parameters:
372: + snes - the `SNES` context
373: - viewer - the `PetscViewer`
375: Options Database Key:
376: . -snes_view - Calls `SNESView()` at end of `SNESSolve()`
378: Level: beginner
380: Notes:
381: The available visualization contexts include
382: + `PETSC_VIEWER_STDOUT_SELF` - standard output (default)
383: - `PETSC_VIEWER_STDOUT_WORLD` - synchronized standard
384: output where only the first processor opens
385: the file. All other processors send their
386: data to the first processor to print.
388: The available formats include
389: + `PETSC_VIEWER_DEFAULT` - standard output (default)
390: - `PETSC_VIEWER_ASCII_INFO_DETAIL` - more verbose output for `SNESNASM`
392: The user can open an alternative visualization context with
393: `PetscViewerASCIIOpen()` - output to a specified file.
395: In the debugger you can do "call `SNESView`(snes,0)" to display the `SNES` solver. (The same holds for any PETSc object viewer).
397: .seealso: [](ch_snes), `SNES`, `SNESLoad()`, `SNESCreate()`, `PetscViewerASCIIOpen()`
398: @*/
399: PetscErrorCode SNESView(SNES snes, PetscViewer viewer)
400: {
401: SNESKSPEW *kctx;
402: KSP ksp;
403: SNESLineSearch linesearch;
404: PetscBool iascii, isstring, isbinary, isdraw;
405: DMSNES dmsnes;
406: #if defined(PETSC_HAVE_SAWS)
407: PetscBool issaws;
408: #endif
410: PetscFunctionBegin;
412: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &viewer));
414: PetscCheckSameComm(snes, 1, viewer, 2);
416: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
417: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
418: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
419: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
420: #if defined(PETSC_HAVE_SAWS)
421: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
422: #endif
423: if (iascii) {
424: SNESNormSchedule normschedule;
425: DM dm;
426: SNESJacobianFn *cJ;
427: void *ctx;
428: const char *pre = "";
430: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)snes, viewer));
431: if (!snes->setupcalled) PetscCall(PetscViewerASCIIPrintf(viewer, " SNES has not been set up so information may be incomplete\n"));
432: if (snes->ops->view) {
433: PetscCall(PetscViewerASCIIPushTab(viewer));
434: PetscUseTypeMethod(snes, view, viewer);
435: PetscCall(PetscViewerASCIIPopTab(viewer));
436: }
437: if (snes->max_funcs == PETSC_UNLIMITED) {
438: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=unlimited\n", snes->max_its));
439: } else {
440: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=%" PetscInt_FMT "\n", snes->max_its, snes->max_funcs));
441: }
442: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%g, absolute=%g, solution=%g\n", (double)snes->rtol, (double)snes->abstol, (double)snes->stol));
443: if (snes->usesksp) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of linear solver iterations=%" PetscInt_FMT "\n", snes->linear_its));
444: PetscCall(PetscViewerASCIIPrintf(viewer, " total number of function evaluations=%" PetscInt_FMT "\n", snes->nfuncs));
445: PetscCall(SNESGetNormSchedule(snes, &normschedule));
446: if (normschedule > 0) PetscCall(PetscViewerASCIIPrintf(viewer, " norm schedule %s\n", SNESNormSchedules[normschedule]));
447: if (snes->gridsequence) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of grid sequence refinements=%" PetscInt_FMT "\n", snes->gridsequence));
448: if (snes->ksp_ewconv) {
449: kctx = (SNESKSPEW *)snes->kspconvctx;
450: if (kctx) {
451: PetscCall(PetscViewerASCIIPrintf(viewer, " Eisenstat-Walker computation of KSP relative tolerance (version %" PetscInt_FMT ")\n", kctx->version));
452: PetscCall(PetscViewerASCIIPrintf(viewer, " rtol_0=%g, rtol_max=%g, threshold=%g\n", (double)kctx->rtol_0, (double)kctx->rtol_max, (double)kctx->threshold));
453: PetscCall(PetscViewerASCIIPrintf(viewer, " gamma=%g, alpha=%g, alpha2=%g\n", (double)kctx->gamma, (double)kctx->alpha, (double)kctx->alpha2));
454: }
455: }
456: if (snes->lagpreconditioner == -1) {
457: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is never rebuilt\n"));
458: } else if (snes->lagpreconditioner > 1) {
459: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is rebuilt every %" PetscInt_FMT " new Jacobians\n", snes->lagpreconditioner));
460: }
461: if (snes->lagjacobian == -1) {
462: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is never rebuilt\n"));
463: } else if (snes->lagjacobian > 1) {
464: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is rebuilt every %" PetscInt_FMT " SNES iterations\n", snes->lagjacobian));
465: }
466: PetscCall(SNESGetDM(snes, &dm));
467: PetscCall(DMSNESGetJacobian(dm, &cJ, &ctx));
468: if (snes->mf_operator) {
469: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing\n"));
470: pre = "Preconditioning ";
471: }
472: if (cJ == SNESComputeJacobianDefault) {
473: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences one column at a time\n", pre));
474: } else if (cJ == SNESComputeJacobianDefaultColor) {
475: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences with coloring\n", pre));
476: /* it slightly breaks data encapsulation for access the DMDA information directly */
477: } else if (cJ == SNESComputeJacobian_DMDA) {
478: MatFDColoring fdcoloring;
479: PetscCall(PetscObjectQuery((PetscObject)dm, "DMDASNES_FDCOLORING", (PetscObject *)&fdcoloring));
480: if (fdcoloring) {
481: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using colored finite differences on a DMDA\n", pre));
482: } else {
483: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using a DMDA local Jacobian\n", pre));
484: }
485: } else if (snes->mf && !snes->mf_operator) {
486: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing, no explicit Jacobian\n"));
487: }
488: } else if (isstring) {
489: const char *type;
490: PetscCall(SNESGetType(snes, &type));
491: PetscCall(PetscViewerStringSPrintf(viewer, " SNESType: %-7.7s", type));
492: PetscTryTypeMethod(snes, view, viewer);
493: } else if (isbinary) {
494: PetscInt classid = SNES_FILE_CLASSID;
495: MPI_Comm comm;
496: PetscMPIInt rank;
497: char type[256];
499: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
500: PetscCallMPI(MPI_Comm_rank(comm, &rank));
501: if (rank == 0) {
502: PetscCall(PetscViewerBinaryWrite(viewer, &classid, 1, PETSC_INT));
503: PetscCall(PetscStrncpy(type, ((PetscObject)snes)->type_name, sizeof(type)));
504: PetscCall(PetscViewerBinaryWrite(viewer, type, sizeof(type), PETSC_CHAR));
505: }
506: PetscTryTypeMethod(snes, view, viewer);
507: } else if (isdraw) {
508: PetscDraw draw;
509: char str[36];
510: PetscReal x, y, bottom, h;
512: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
513: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
514: PetscCall(PetscStrncpy(str, "SNES: ", sizeof(str)));
515: PetscCall(PetscStrlcat(str, ((PetscObject)snes)->type_name, sizeof(str)));
516: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_BLUE, PETSC_DRAW_BLACK, str, NULL, &h));
517: bottom = y - h;
518: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
519: PetscTryTypeMethod(snes, view, viewer);
520: #if defined(PETSC_HAVE_SAWS)
521: } else if (issaws) {
522: PetscMPIInt rank;
523: const char *name;
525: PetscCall(PetscObjectGetName((PetscObject)snes, &name));
526: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
527: if (!((PetscObject)snes)->amsmem && rank == 0) {
528: char dir[1024];
530: PetscCall(PetscObjectViewSAWs((PetscObject)snes, viewer));
531: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/its", name));
532: PetscCallSAWs(SAWs_Register, (dir, &snes->iter, 1, SAWs_READ, SAWs_INT));
533: if (!snes->conv_hist) PetscCall(SNESSetConvergenceHistory(snes, NULL, NULL, PETSC_DECIDE, PETSC_TRUE));
534: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/conv_hist", name));
535: PetscCallSAWs(SAWs_Register, (dir, snes->conv_hist, 10, SAWs_READ, SAWs_DOUBLE));
536: }
537: #endif
538: }
539: if (snes->linesearch) {
540: PetscCall(SNESGetLineSearch(snes, &linesearch));
541: PetscCall(PetscViewerASCIIPushTab(viewer));
542: PetscCall(SNESLineSearchView(linesearch, viewer));
543: PetscCall(PetscViewerASCIIPopTab(viewer));
544: }
545: if (snes->npc && snes->usesnpc) {
546: PetscCall(PetscViewerASCIIPushTab(viewer));
547: PetscCall(SNESView(snes->npc, viewer));
548: PetscCall(PetscViewerASCIIPopTab(viewer));
549: }
550: PetscCall(PetscViewerASCIIPushTab(viewer));
551: PetscCall(DMGetDMSNES(snes->dm, &dmsnes));
552: PetscCall(DMSNESView(dmsnes, viewer));
553: PetscCall(PetscViewerASCIIPopTab(viewer));
554: if (snes->usesksp) {
555: PetscCall(SNESGetKSP(snes, &ksp));
556: PetscCall(PetscViewerASCIIPushTab(viewer));
557: PetscCall(KSPView(ksp, viewer));
558: PetscCall(PetscViewerASCIIPopTab(viewer));
559: }
560: if (isdraw) {
561: PetscDraw draw;
562: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
563: PetscCall(PetscDrawPopCurrentPoint(draw));
564: }
565: PetscFunctionReturn(PETSC_SUCCESS);
566: }
568: /*
569: We retain a list of functions that also take SNES command
570: line options. These are called at the end SNESSetFromOptions()
571: */
572: #define MAXSETFROMOPTIONS 5
573: static PetscInt numberofsetfromoptions;
574: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);
576: /*@C
577: SNESAddOptionsChecker - Adds an additional function to check for `SNES` options.
579: Not Collective
581: Input Parameter:
582: . snescheck - function that checks for options
584: Calling sequence of `snescheck`:
585: . snes - the `SNES` object for which it is checking options
587: Level: developer
589: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`
590: @*/
591: PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES snes))
592: {
593: PetscFunctionBegin;
594: PetscCheck(numberofsetfromoptions < MAXSETFROMOPTIONS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %d allowed", MAXSETFROMOPTIONS);
595: othersetfromoptions[numberofsetfromoptions++] = snescheck;
596: PetscFunctionReturn(PETSC_SUCCESS);
597: }
599: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
600: {
601: Mat J;
602: MatNullSpace nullsp;
604: PetscFunctionBegin;
607: if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
608: Mat A = snes->jacobian, B = snes->jacobian_pre;
609: PetscCall(MatCreateVecs(A ? A : B, NULL, &snes->vec_func));
610: }
612: PetscCheck(version == 1 || version == 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator routines, only version 1 and 2");
613: if (version == 1) {
614: PetscCall(MatCreateSNESMF(snes, &J));
615: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
616: PetscCall(MatSetFromOptions(J));
617: /* TODO: the version 2 code should be merged into the MatCreateSNESMF() and MatCreateMFFD() infrastructure and then removed */
618: } else /* if (version == 2) */ {
619: PetscCheck(snes->vec_func, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "SNESSetFunction() must be called first");
620: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
621: PetscCall(MatCreateSNESMFMore(snes, snes->vec_func, &J));
622: #else
623: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "matrix-free operator routines (version 2)");
624: #endif
625: }
627: /* attach any user provided null space that was on Amat to the newly created matrix-free matrix */
628: if (snes->jacobian) {
629: PetscCall(MatGetNullSpace(snes->jacobian, &nullsp));
630: if (nullsp) PetscCall(MatSetNullSpace(J, nullsp));
631: }
633: PetscCall(PetscInfo(snes, "Setting default matrix-free operator routines (version %" PetscInt_FMT ")\n", version));
634: if (hasOperator) {
635: /* This version replaces the user provided Jacobian matrix with a
636: matrix-free version but still employs the user-provided matrix used for computing the preconditioner. */
637: PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
638: } else {
639: /* This version replaces both the user-provided Jacobian and the user-
640: provided preconditioner Jacobian with the default matrix-free version. */
641: if (snes->npcside == PC_LEFT && snes->npc) {
642: if (!snes->jacobian) PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
643: } else {
644: KSP ksp;
645: PC pc;
646: PetscBool match;
648: PetscCall(SNESSetJacobian(snes, J, J, MatMFFDComputeJacobian, NULL));
649: /* Force no preconditioner */
650: PetscCall(SNESGetKSP(snes, &ksp));
651: PetscCall(KSPGetPC(ksp, &pc));
652: PetscCall(PetscObjectTypeCompareAny((PetscObject)pc, &match, PCSHELL, PCH2OPUS, ""));
653: if (!match) {
654: PetscCall(PetscInfo(snes, "Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n"));
655: PetscCall(PCSetType(pc, PCNONE));
656: }
657: }
658: }
659: PetscCall(MatDestroy(&J));
660: PetscFunctionReturn(PETSC_SUCCESS);
661: }
663: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine, Mat Restrict, Vec Rscale, Mat Inject, DM dmcoarse, void *ctx)
664: {
665: SNES snes = (SNES)ctx;
666: Vec Xfine, Xfine_named = NULL, Xcoarse;
668: PetscFunctionBegin;
669: if (PetscLogPrintInfo) {
670: PetscInt finelevel, coarselevel, fineclevel, coarseclevel;
671: PetscCall(DMGetRefineLevel(dmfine, &finelevel));
672: PetscCall(DMGetCoarsenLevel(dmfine, &fineclevel));
673: PetscCall(DMGetRefineLevel(dmcoarse, &coarselevel));
674: PetscCall(DMGetCoarsenLevel(dmcoarse, &coarseclevel));
675: PetscCall(PetscInfo(dmfine, "Restricting SNES solution vector from level %" PetscInt_FMT "-%" PetscInt_FMT " to level %" PetscInt_FMT "-%" PetscInt_FMT "\n", finelevel, fineclevel, coarselevel, coarseclevel));
676: }
677: if (dmfine == snes->dm) Xfine = snes->vec_sol;
678: else {
679: PetscCall(DMGetNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
680: Xfine = Xfine_named;
681: }
682: PetscCall(DMGetNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
683: if (Inject) {
684: PetscCall(MatRestrict(Inject, Xfine, Xcoarse));
685: } else {
686: PetscCall(MatRestrict(Restrict, Xfine, Xcoarse));
687: PetscCall(VecPointwiseMult(Xcoarse, Xcoarse, Rscale));
688: }
689: PetscCall(DMRestoreNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
690: if (Xfine_named) PetscCall(DMRestoreNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
691: PetscFunctionReturn(PETSC_SUCCESS);
692: }
694: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm, DM dmc, void *ctx)
695: {
696: PetscFunctionBegin;
697: PetscCall(DMCoarsenHookAdd(dmc, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, ctx));
698: PetscFunctionReturn(PETSC_SUCCESS);
699: }
701: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
702: * safely call SNESGetDM() in their residual evaluation routine. */
703: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp, Mat A, Mat B, void *ctx)
704: {
705: SNES snes = (SNES)ctx;
706: DMSNES sdm;
707: Vec X, Xnamed = NULL;
708: DM dmsave;
709: void *ctxsave;
710: SNESJacobianFn *jac = NULL;
712: PetscFunctionBegin;
713: dmsave = snes->dm;
714: PetscCall(KSPGetDM(ksp, &snes->dm));
715: if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
716: else {
717: PetscBool has;
719: /* We are on a coarser level, this vec was initialized using a DM restrict hook */
720: PetscCall(DMHasNamedGlobalVector(snes->dm, "SNESVecSol", &has));
721: PetscCheck(has, PetscObjectComm((PetscObject)snes->dm), PETSC_ERR_PLIB, "Missing SNESVecSol");
722: PetscCall(DMGetNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
723: X = Xnamed;
724: PetscCall(SNESGetJacobian(snes, NULL, NULL, &jac, &ctxsave));
725: /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
726: if (jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, SNESComputeJacobianDefaultColor, NULL));
727: }
729: /* Compute the operators */
730: PetscCall(DMGetDMSNES(snes->dm, &sdm));
731: if (Xnamed && sdm->ops->computefunction) {
732: /* The SNES contract with the user is that ComputeFunction is always called before ComputeJacobian.
733: We make sure of this here. Disable affine shift since it is for the finest level */
734: Vec F, saverhs = snes->vec_rhs;
736: snes->vec_rhs = NULL;
737: PetscCall(DMGetGlobalVector(snes->dm, &F));
738: PetscCall(SNESComputeFunction(snes, X, F));
739: PetscCall(DMRestoreGlobalVector(snes->dm, &F));
740: snes->vec_rhs = saverhs;
741: snes->nfuncs--; /* Do not log coarser level evaluations */
742: }
743: /* Make sure KSP DM has the Jacobian computation routine */
744: if (!sdm->ops->computejacobian) PetscCall(DMCopyDMSNES(dmsave, snes->dm));
745: PetscCall(SNESComputeJacobian(snes, X, A, B));
747: /* Put the previous context back */
748: if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, jac, ctxsave));
750: if (Xnamed) PetscCall(DMRestoreNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
751: snes->dm = dmsave;
752: PetscFunctionReturn(PETSC_SUCCESS);
753: }
755: /*@
756: SNESSetUpMatrices - ensures that matrices are available for `SNES` Newton-like methods, this is called by `SNESSetUp_XXX()`
758: Collective
760: Input Parameter:
761: . snes - `SNES` object to configure
763: Level: developer
765: Note:
766: If the matrices do not yet exist it attempts to create them based on options previously set for the `SNES` such as `-snes_mf`
768: Developer Note:
769: The functionality of this routine overlaps in a confusing way with the functionality of `SNESSetUpMatrixFree_Private()` which is called by
770: `SNESSetUp()` but sometimes `SNESSetUpMatrices()` is called without `SNESSetUp()` being called. A refactorization to simplify the
771: logic that handles the matrix-free case is desirable.
773: .seealso: [](ch_snes), `SNES`, `SNESSetUp()`
774: @*/
775: PetscErrorCode SNESSetUpMatrices(SNES snes)
776: {
777: DM dm;
778: DMSNES sdm;
780: PetscFunctionBegin;
781: PetscCall(SNESGetDM(snes, &dm));
782: PetscCall(DMGetDMSNES(dm, &sdm));
783: if (!snes->jacobian && snes->mf && !snes->mf_operator && !snes->jacobian_pre) {
784: Mat J;
785: void *functx;
786: PetscCall(MatCreateSNESMF(snes, &J));
787: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
788: PetscCall(MatSetFromOptions(J));
789: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
790: PetscCall(SNESSetJacobian(snes, J, J, NULL, NULL));
791: PetscCall(MatDestroy(&J));
792: } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
793: Mat J, B;
794: PetscCall(MatCreateSNESMF(snes, &J));
795: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
796: PetscCall(MatSetFromOptions(J));
797: PetscCall(DMCreateMatrix(snes->dm, &B));
798: /* sdm->computejacobian was already set to reach here */
799: PetscCall(SNESSetJacobian(snes, J, B, NULL, NULL));
800: PetscCall(MatDestroy(&J));
801: PetscCall(MatDestroy(&B));
802: } else if (!snes->jacobian_pre) {
803: PetscDS prob;
804: Mat J, B;
805: PetscBool hasPrec = PETSC_FALSE;
807: J = snes->jacobian;
808: PetscCall(DMGetDS(dm, &prob));
809: if (prob) PetscCall(PetscDSHasJacobianPreconditioner(prob, &hasPrec));
810: if (J) PetscCall(PetscObjectReference((PetscObject)J));
811: else if (hasPrec) PetscCall(DMCreateMatrix(snes->dm, &J));
812: PetscCall(DMCreateMatrix(snes->dm, &B));
813: PetscCall(SNESSetJacobian(snes, J ? J : B, B, NULL, NULL));
814: PetscCall(MatDestroy(&J));
815: PetscCall(MatDestroy(&B));
816: }
817: {
818: KSP ksp;
819: PetscCall(SNESGetKSP(snes, &ksp));
820: PetscCall(KSPSetComputeOperators(ksp, KSPComputeOperators_SNES, snes));
821: PetscCall(DMCoarsenHookAdd(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
822: }
823: PetscFunctionReturn(PETSC_SUCCESS);
824: }
826: PETSC_EXTERN PetscErrorCode PetscMonitorPauseFinal_Internal(PetscInt, void *);
828: static PetscErrorCode SNESMonitorPauseFinal_Internal(SNES snes)
829: {
830: PetscFunctionBegin;
831: if (!snes->pauseFinal) PetscFunctionReturn(PETSC_SUCCESS);
832: PetscCall(PetscMonitorPauseFinal_Internal(snes->numbermonitors, snes->monitorcontext));
833: PetscFunctionReturn(PETSC_SUCCESS);
834: }
836: /*@C
837: SNESMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user
839: Collective
841: Input Parameters:
842: + snes - `SNES` object you wish to monitor
843: . name - the monitor type one is seeking
844: . help - message indicating what monitoring is done
845: . manual - manual page for the monitor
846: . monitor - the monitor function, this must use a `PetscViewerFormat` as its context
847: - 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
849: Calling sequence of `monitor`:
850: + snes - the nonlinear solver context
851: . it - the current iteration
852: . r - the current function norm
853: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
855: Calling sequence of `monitorsetup`:
856: + snes - the nonlinear solver context
857: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
859: Options Database Key:
860: . -name - trigger the use of this monitor in `SNESSetFromOptions()`
862: Level: advanced
864: .seealso: [](ch_snes), `PetscOptionsCreateViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
865: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`
866: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
867: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
868: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
869: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
870: `PetscOptionsFList()`, `PetscOptionsEList()`
871: @*/
872: 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))
873: {
874: PetscViewer viewer;
875: PetscViewerFormat format;
876: PetscBool flg;
878: PetscFunctionBegin;
879: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, name, &viewer, &format, &flg));
880: if (flg) {
881: PetscViewerAndFormat *vf;
882: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
883: PetscCall(PetscViewerDestroy(&viewer));
884: if (monitorsetup) PetscCall((*monitorsetup)(snes, vf));
885: PetscCall(SNESMonitorSet(snes, (PetscErrorCode (*)(SNES, PetscInt, PetscReal, void *))monitor, vf, (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy));
886: }
887: PetscFunctionReturn(PETSC_SUCCESS);
888: }
890: PetscErrorCode SNESEWSetFromOptions_Private(SNESKSPEW *kctx, PetscBool print_api, MPI_Comm comm, const char *prefix)
891: {
892: const char *api = print_api ? "SNESKSPSetParametersEW" : NULL;
894: PetscFunctionBegin;
895: PetscOptionsBegin(comm, prefix, "Eisenstat and Walker type forcing options", "KSP");
896: PetscCall(PetscOptionsInt("-ksp_ew_version", "Version 1, 2 or 3", api, kctx->version, &kctx->version, NULL));
897: PetscCall(PetscOptionsReal("-ksp_ew_rtol0", "0 <= rtol0 < 1", api, kctx->rtol_0, &kctx->rtol_0, NULL));
898: kctx->rtol_max = PetscMax(kctx->rtol_0, kctx->rtol_max);
899: PetscCall(PetscOptionsReal("-ksp_ew_rtolmax", "0 <= rtolmax < 1", api, kctx->rtol_max, &kctx->rtol_max, NULL));
900: PetscCall(PetscOptionsReal("-ksp_ew_gamma", "0 <= gamma <= 1", api, kctx->gamma, &kctx->gamma, NULL));
901: PetscCall(PetscOptionsReal("-ksp_ew_alpha", "1 < alpha <= 2", api, kctx->alpha, &kctx->alpha, NULL));
902: PetscCall(PetscOptionsReal("-ksp_ew_alpha2", "alpha2", NULL, kctx->alpha2, &kctx->alpha2, NULL));
903: PetscCall(PetscOptionsReal("-ksp_ew_threshold", "0 < threshold < 1", api, kctx->threshold, &kctx->threshold, NULL));
904: PetscCall(PetscOptionsReal("-ksp_ew_v4_p1", "p1", NULL, kctx->v4_p1, &kctx->v4_p1, NULL));
905: PetscCall(PetscOptionsReal("-ksp_ew_v4_p2", "p2", NULL, kctx->v4_p2, &kctx->v4_p2, NULL));
906: PetscCall(PetscOptionsReal("-ksp_ew_v4_p3", "p3", NULL, kctx->v4_p3, &kctx->v4_p3, NULL));
907: PetscCall(PetscOptionsReal("-ksp_ew_v4_m1", "Scaling when rk-1 in [p2,p3)", NULL, kctx->v4_m1, &kctx->v4_m1, NULL));
908: PetscCall(PetscOptionsReal("-ksp_ew_v4_m2", "Scaling when rk-1 in [p3,+infty)", NULL, kctx->v4_m2, &kctx->v4_m2, NULL));
909: PetscCall(PetscOptionsReal("-ksp_ew_v4_m3", "Threshold for successive rtol (0.1 in Eq.7)", NULL, kctx->v4_m3, &kctx->v4_m3, NULL));
910: PetscCall(PetscOptionsReal("-ksp_ew_v4_m4", "Adaptation scaling (0.5 in Eq.7)", NULL, kctx->v4_m4, &kctx->v4_m4, NULL));
911: PetscOptionsEnd();
912: PetscFunctionReturn(PETSC_SUCCESS);
913: }
915: /*@
916: SNESSetFromOptions - Sets various `SNES` and `KSP` parameters from user options.
918: Collective
920: Input Parameter:
921: . snes - the `SNES` context
923: Options Database Keys:
924: + -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, `SNESType` for complete list
925: . -snes_rtol <rtol> - relative decrease in tolerance norm from initial
926: . -snes_atol <abstol> - absolute tolerance of residual norm
927: . -snes_stol <stol> - convergence tolerance in terms of the norm of the change in the solution between steps
928: . -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
929: . -snes_max_it <max_it> - maximum number of iterations
930: . -snes_max_funcs <max_funcs> - maximum number of function evaluations
931: . -snes_force_iteration <force> - force `SNESSolve()` to take at least one iteration
932: . -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
933: . -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
934: . -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
935: . -snes_lag_preconditioner_persists <true,false> - retains the -snes_lag_preconditioner information across multiple SNESSolve()
936: . -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
937: . -snes_lag_jacobian_persists <true,false> - retains the -snes_lag_jacobian information across multiple SNESSolve()
938: . -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.
939: . -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
940: . -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
941: . -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
942: . -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
943: . -snes_monitor_lg_residualnorm - plots residual norm at each iteration
944: . -snes_monitor_lg_range - plots residual norm at each iteration
945: . -snes_monitor_pause_final - Pauses all monitor drawing after the solver ends
946: . -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
947: . -snes_fd_color - use finite differences with coloring to compute Jacobian
948: . -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each `KSP` iteration
949: . -snes_converged_reason - print the reason for convergence/divergence after each solve
950: . -npc_snes_type <type> - the `SNES` type to use as a nonlinear preconditioner
951: . -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.
952: - -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.
954: Options Database Keys for Eisenstat-Walker method:
955: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
956: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
957: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
958: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
959: . -snes_ksp_ew_gamma <gamma> - Sets gamma
960: . -snes_ksp_ew_alpha <alpha> - Sets alpha
961: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
962: - -snes_ksp_ew_threshold <threshold> - Sets threshold
964: Level: beginner
966: Notes:
967: To see all options, run your program with the -help option or consult the users manual
969: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
970: and computing explicitly with
971: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
973: .seealso: [](ch_snes), `SNESType`, `SNESSetOptionsPrefix()`, `SNESResetFromOptions()`, `SNES`, `SNESCreate()`, `MatCreateSNESMF()`, `MatFDColoring`
974: @*/
975: PetscErrorCode SNESSetFromOptions(SNES snes)
976: {
977: PetscBool flg, pcset, persist, set;
978: PetscInt i, indx, lag, grids, max_its, max_funcs;
979: const char *deft = SNESNEWTONLS;
980: const char *convtests[] = {"default", "skip", "correct_pressure"};
981: SNESKSPEW *kctx = NULL;
982: char type[256], monfilename[PETSC_MAX_PATH_LEN], ewprefix[256];
983: PCSide pcside;
984: const char *optionsprefix;
985: PetscReal rtol, abstol, stol;
987: PetscFunctionBegin;
989: PetscCall(SNESRegisterAll());
990: PetscObjectOptionsBegin((PetscObject)snes);
991: if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
992: PetscCall(PetscOptionsFList("-snes_type", "Nonlinear solver method", "SNESSetType", SNESList, deft, type, 256, &flg));
993: if (flg) {
994: PetscCall(SNESSetType(snes, type));
995: } else if (!((PetscObject)snes)->type_name) {
996: PetscCall(SNESSetType(snes, deft));
997: }
999: abstol = snes->abstol;
1000: rtol = snes->rtol;
1001: stol = snes->stol;
1002: max_its = snes->max_its;
1003: max_funcs = snes->max_funcs;
1004: PetscCall(PetscOptionsReal("-snes_rtol", "Stop if decrease in function norm less than", "SNESSetTolerances", snes->rtol, &rtol, NULL));
1005: PetscCall(PetscOptionsReal("-snes_atol", "Stop if function norm less than", "SNESSetTolerances", snes->abstol, &abstol, NULL));
1006: PetscCall(PetscOptionsReal("-snes_stol", "Stop if step length less than", "SNESSetTolerances", snes->stol, &stol, NULL));
1007: PetscCall(PetscOptionsInt("-snes_max_it", "Maximum iterations", "SNESSetTolerances", snes->max_its, &max_its, NULL));
1008: PetscCall(PetscOptionsInt("-snes_max_funcs", "Maximum function evaluations", "SNESSetTolerances", snes->max_funcs, &max_funcs, NULL));
1009: PetscCall(SNESSetTolerances(snes, abstol, rtol, stol, max_its, max_funcs));
1011: PetscCall(PetscOptionsReal("-snes_divergence_tolerance", "Stop if residual norm increases by this factor", "SNESSetDivergenceTolerance", snes->divtol, &snes->divtol, &flg));
1012: if (flg) PetscCall(SNESSetDivergenceTolerance(snes, snes->divtol));
1014: PetscCall(PetscOptionsInt("-snes_max_fail", "Maximum nonlinear step failures", "SNESSetMaxNonlinearStepFailures", snes->maxFailures, &snes->maxFailures, &flg));
1015: if (flg) PetscCall(SNESSetMaxNonlinearStepFailures(snes, snes->maxFailures));
1017: PetscCall(PetscOptionsInt("-snes_max_linear_solve_fail", "Maximum failures in linear solves allowed", "SNESSetMaxLinearSolveFailures", snes->maxLinearSolveFailures, &snes->maxLinearSolveFailures, &flg));
1018: if (flg) PetscCall(SNESSetMaxLinearSolveFailures(snes, snes->maxLinearSolveFailures));
1020: PetscCall(PetscOptionsBool("-snes_error_if_not_converged", "Generate error if solver does not converge", "SNESSetErrorIfNotConverged", snes->errorifnotconverged, &snes->errorifnotconverged, NULL));
1021: PetscCall(PetscOptionsBool("-snes_force_iteration", "Force SNESSolve() to take at least one iteration", "SNESSetForceIteration", snes->forceiteration, &snes->forceiteration, NULL));
1022: PetscCall(PetscOptionsBool("-snes_check_jacobian_domain_error", "Check Jacobian domain error after Jacobian evaluation", "SNESCheckJacobianDomainError", snes->checkjacdomainerror, &snes->checkjacdomainerror, NULL));
1024: PetscCall(PetscOptionsInt("-snes_lag_preconditioner", "How often to rebuild preconditioner", "SNESSetLagPreconditioner", snes->lagpreconditioner, &lag, &flg));
1025: if (flg) {
1026: 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");
1027: PetscCall(SNESSetLagPreconditioner(snes, lag));
1028: }
1029: PetscCall(PetscOptionsBool("-snes_lag_preconditioner_persists", "Preconditioner lagging through multiple SNES solves", "SNESSetLagPreconditionerPersists", snes->lagjac_persist, &persist, &flg));
1030: if (flg) PetscCall(SNESSetLagPreconditionerPersists(snes, persist));
1031: PetscCall(PetscOptionsInt("-snes_lag_jacobian", "How often to rebuild Jacobian", "SNESSetLagJacobian", snes->lagjacobian, &lag, &flg));
1032: if (flg) {
1033: 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");
1034: PetscCall(SNESSetLagJacobian(snes, lag));
1035: }
1036: PetscCall(PetscOptionsBool("-snes_lag_jacobian_persists", "Jacobian lagging through multiple SNES solves", "SNESSetLagJacobianPersists", snes->lagjac_persist, &persist, &flg));
1037: if (flg) PetscCall(SNESSetLagJacobianPersists(snes, persist));
1039: PetscCall(PetscOptionsInt("-snes_grid_sequence", "Use grid sequencing to generate initial guess", "SNESSetGridSequence", snes->gridsequence, &grids, &flg));
1040: if (flg) PetscCall(SNESSetGridSequence(snes, grids));
1042: PetscCall(PetscOptionsEList("-snes_convergence_test", "Convergence test", "SNESSetConvergenceTest", convtests, PETSC_STATIC_ARRAY_LENGTH(convtests), "default", &indx, &flg));
1043: if (flg) {
1044: switch (indx) {
1045: case 0:
1046: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedDefault, NULL, NULL));
1047: break;
1048: case 1:
1049: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedSkip, NULL, NULL));
1050: break;
1051: case 2:
1052: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedCorrectPressure, NULL, NULL));
1053: break;
1054: }
1055: }
1057: PetscCall(PetscOptionsEList("-snes_norm_schedule", "SNES Norm schedule", "SNESSetNormSchedule", SNESNormSchedules, 5, "function", &indx, &flg));
1058: if (flg) PetscCall(SNESSetNormSchedule(snes, (SNESNormSchedule)indx));
1060: PetscCall(PetscOptionsEList("-snes_function_type", "SNES Norm schedule", "SNESSetFunctionType", SNESFunctionTypes, 2, "unpreconditioned", &indx, &flg));
1061: if (flg) PetscCall(SNESSetFunctionType(snes, (SNESFunctionType)indx));
1063: kctx = (SNESKSPEW *)snes->kspconvctx;
1065: PetscCall(PetscOptionsBool("-snes_ksp_ew", "Use Eisentat-Walker linear system convergence test", "SNESKSPSetUseEW", snes->ksp_ewconv, &snes->ksp_ewconv, NULL));
1067: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1068: PetscCall(PetscSNPrintf(ewprefix, sizeof(ewprefix), "%s%s", optionsprefix ? optionsprefix : "", "snes_"));
1069: PetscCall(SNESEWSetFromOptions_Private(kctx, PETSC_TRUE, PetscObjectComm((PetscObject)snes), ewprefix));
1071: flg = PETSC_FALSE;
1072: PetscCall(PetscOptionsBool("-snes_monitor_cancel", "Remove all monitors", "SNESMonitorCancel", flg, &flg, &set));
1073: if (set && flg) PetscCall(SNESMonitorCancel(snes));
1075: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor", "Monitor norm of function", "SNESMonitorDefault", SNESMonitorDefault, SNESMonitorDefaultSetUp));
1076: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_short", "Monitor norm of function with fewer digits", "SNESMonitorDefaultShort", SNESMonitorDefaultShort, NULL));
1077: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_range", "Monitor range of elements of function", "SNESMonitorRange", SNESMonitorRange, NULL));
1079: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_ratio", "Monitor ratios of the norm of function for consecutive steps", "SNESMonitorRatio", SNESMonitorRatio, SNESMonitorRatioSetUp));
1080: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_field", "Monitor norm of function (split into fields)", "SNESMonitorDefaultField", SNESMonitorDefaultField, NULL));
1081: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution", "View solution at each iteration", "SNESMonitorSolution", SNESMonitorSolution, NULL));
1082: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution_update", "View correction at each iteration", "SNESMonitorSolutionUpdate", SNESMonitorSolutionUpdate, NULL));
1083: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_residual", "View residual at each iteration", "SNESMonitorResidual", SNESMonitorResidual, NULL));
1084: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_jacupdate_spectrum", "Print the change in the spectrum of the Jacobian", "SNESMonitorJacUpdateSpectrum", SNESMonitorJacUpdateSpectrum, NULL));
1085: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_fields", "Monitor norm of function per field", "SNESMonitorSet", SNESMonitorFields, NULL));
1086: PetscCall(PetscOptionsBool("-snes_monitor_pause_final", "Pauses all draw monitors at the final iterate", "SNESMonitorPauseFinal_Internal", PETSC_FALSE, &snes->pauseFinal, NULL));
1088: PetscCall(PetscOptionsString("-snes_monitor_python", "Use Python function", "SNESMonitorSet", NULL, monfilename, sizeof(monfilename), &flg));
1089: if (flg) PetscCall(PetscPythonMonitorSet((PetscObject)snes, monfilename));
1091: flg = PETSC_FALSE;
1092: PetscCall(PetscOptionsBool("-snes_monitor_lg_range", "Plot function range at each iteration", "SNESMonitorLGRange", flg, &flg, NULL));
1093: if (flg) {
1094: PetscViewer ctx;
1096: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, NULL, PETSC_DECIDE, PETSC_DECIDE, 400, 300, &ctx));
1097: PetscCall(SNESMonitorSet(snes, SNESMonitorLGRange, ctx, (PetscCtxDestroyFn *)PetscViewerDestroy));
1098: }
1100: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
1101: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_converged_reason", &snes->convergedreasonviewer, &snes->convergedreasonformat, NULL));
1102: flg = PETSC_FALSE;
1103: PetscCall(PetscOptionsBool("-snes_converged_reason_view_cancel", "Remove all converged reason viewers", "SNESConvergedReasonViewCancel", flg, &flg, &set));
1104: if (set && flg) PetscCall(SNESConvergedReasonViewCancel(snes));
1106: flg = PETSC_FALSE;
1107: PetscCall(PetscOptionsBool("-snes_fd", "Use finite differences (slow) to compute Jacobian", "SNESComputeJacobianDefault", flg, &flg, NULL));
1108: if (flg) {
1109: void *functx;
1110: DM dm;
1111: PetscCall(SNESGetDM(snes, &dm));
1112: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1113: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
1114: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefault, functx));
1115: PetscCall(PetscInfo(snes, "Setting default finite difference Jacobian matrix\n"));
1116: }
1118: flg = PETSC_FALSE;
1119: PetscCall(PetscOptionsBool("-snes_fd_function", "Use finite differences (slow) to compute function from user objective", "SNESObjectiveComputeFunctionDefaultFD", flg, &flg, NULL));
1120: if (flg) PetscCall(SNESSetFunction(snes, NULL, SNESObjectiveComputeFunctionDefaultFD, NULL));
1122: flg = PETSC_FALSE;
1123: PetscCall(PetscOptionsBool("-snes_fd_color", "Use finite differences with coloring to compute Jacobian", "SNESComputeJacobianDefaultColor", flg, &flg, NULL));
1124: if (flg) {
1125: DM dm;
1126: PetscCall(SNESGetDM(snes, &dm));
1127: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1128: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefaultColor, NULL));
1129: PetscCall(PetscInfo(snes, "Setting default finite difference coloring Jacobian matrix\n"));
1130: }
1132: flg = PETSC_FALSE;
1133: 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));
1134: if (flg && snes->mf_operator) {
1135: snes->mf_operator = PETSC_TRUE;
1136: snes->mf = PETSC_TRUE;
1137: }
1138: flg = PETSC_FALSE;
1139: PetscCall(PetscOptionsBool("-snes_mf", "Use a Matrix-Free Jacobian with no matrix for computing the preconditioner", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf, &flg));
1140: if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1141: PetscCall(PetscOptionsInt("-snes_mf_version", "Matrix-Free routines version 1 or 2", "None", snes->mf_version, &snes->mf_version, NULL));
1143: flg = PETSC_FALSE;
1144: PetscCall(SNESGetNPCSide(snes, &pcside));
1145: PetscCall(PetscOptionsEnum("-snes_npc_side", "SNES nonlinear preconditioner side", "SNESSetNPCSide", PCSides, (PetscEnum)pcside, (PetscEnum *)&pcside, &flg));
1146: if (flg) PetscCall(SNESSetNPCSide(snes, pcside));
1148: #if defined(PETSC_HAVE_SAWS)
1149: /*
1150: Publish convergence information using SAWs
1151: */
1152: flg = PETSC_FALSE;
1153: PetscCall(PetscOptionsBool("-snes_monitor_saws", "Publish SNES progress using SAWs", "SNESMonitorSet", flg, &flg, NULL));
1154: if (flg) {
1155: void *ctx;
1156: PetscCall(SNESMonitorSAWsCreate(snes, &ctx));
1157: PetscCall(SNESMonitorSet(snes, SNESMonitorSAWs, ctx, SNESMonitorSAWsDestroy));
1158: }
1159: #endif
1160: #if defined(PETSC_HAVE_SAWS)
1161: {
1162: PetscBool set;
1163: flg = PETSC_FALSE;
1164: PetscCall(PetscOptionsBool("-snes_saws_block", "Block for SAWs at end of SNESSolve", "PetscObjectSAWsBlock", ((PetscObject)snes)->amspublishblock, &flg, &set));
1165: if (set) PetscCall(PetscObjectSAWsSetBlock((PetscObject)snes, flg));
1166: }
1167: #endif
1169: for (i = 0; i < numberofsetfromoptions; i++) PetscCall((*othersetfromoptions[i])(snes));
1171: PetscTryTypeMethod(snes, setfromoptions, PetscOptionsObject);
1173: /* process any options handlers added with PetscObjectAddOptionsHandler() */
1174: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)snes, PetscOptionsObject));
1175: PetscOptionsEnd();
1177: if (snes->linesearch) {
1178: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
1179: PetscCall(SNESLineSearchSetFromOptions(snes->linesearch));
1180: }
1182: if (snes->usesksp) {
1183: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
1184: PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre));
1185: PetscCall(KSPSetFromOptions(snes->ksp));
1186: }
1188: /* if user has set the SNES NPC type via options database, create it. */
1189: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1190: PetscCall(PetscOptionsHasName(((PetscObject)snes)->options, optionsprefix, "-npc_snes_type", &pcset));
1191: if (pcset && (!snes->npc)) PetscCall(SNESGetNPC(snes, &snes->npc));
1192: if (snes->npc) PetscCall(SNESSetFromOptions(snes->npc));
1193: snes->setfromoptionscalled++;
1194: PetscFunctionReturn(PETSC_SUCCESS);
1195: }
1197: /*@
1198: SNESResetFromOptions - Sets various `SNES` and `KSP` parameters from user options ONLY if the `SNESSetFromOptions()` was previously called
1200: Collective
1202: Input Parameter:
1203: . snes - the `SNES` context
1205: Level: advanced
1207: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESSetOptionsPrefix()`
1208: @*/
1209: PetscErrorCode SNESResetFromOptions(SNES snes)
1210: {
1211: PetscFunctionBegin;
1212: if (snes->setfromoptionscalled) PetscCall(SNESSetFromOptions(snes));
1213: PetscFunctionReturn(PETSC_SUCCESS);
1214: }
1216: /*@C
1217: SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1218: the nonlinear solvers.
1220: Logically Collective; No Fortran Support
1222: Input Parameters:
1223: + snes - the `SNES` context
1224: . compute - function to compute the context
1225: - destroy - function to destroy the context, see `PetscCtxDestroyFn` for the calling sequence
1227: Calling sequence of `compute`:
1228: + snes - the `SNES` context
1229: - ctx - context to be computed
1231: Level: intermediate
1233: Note:
1234: This routine is useful if you are performing grid sequencing or using `SNESFAS` and need the appropriate context generated for each level.
1236: Use `SNESSetApplicationContext()` to see the context immediately
1238: .seealso: [](ch_snes), `SNESGetApplicationContext()`, `SNESSetApplicationContext()`, `PetscCtxDestroyFn`
1239: @*/
1240: PetscErrorCode SNESSetComputeApplicationContext(SNES snes, PetscErrorCode (*compute)(SNES snes, void **ctx), PetscCtxDestroyFn *destroy)
1241: {
1242: PetscFunctionBegin;
1244: snes->ops->usercompute = compute;
1245: snes->ops->ctxdestroy = destroy;
1246: PetscFunctionReturn(PETSC_SUCCESS);
1247: }
1249: /*@
1250: SNESSetApplicationContext - Sets the optional user-defined context for the nonlinear solvers.
1252: Logically Collective
1254: Input Parameters:
1255: + snes - the `SNES` context
1256: - ctx - the user context
1258: Level: intermediate
1260: Notes:
1261: Users can provide a context when constructing the `SNES` options and then access it inside their function, Jacobian computation, or other evaluation function
1262: with `SNESGetApplicationContext()`
1264: To provide a function that computes the context for you use `SNESSetComputeApplicationContext()`
1266: Fortran Note:
1267: This only works when `ctx` is a Fortran derived type (it cannot be a `PetscObject`), we recommend writing a Fortran interface definition for this
1268: function that tells the Fortran compiler the derived data type that is passed in as the `ctx` argument. See `SNESGetApplicationContext()` for
1269: an example.
1271: .seealso: [](ch_snes), `SNES`, `SNESSetComputeApplicationContext()`, `SNESGetApplicationContext()`
1272: @*/
1273: PetscErrorCode SNESSetApplicationContext(SNES snes, void *ctx)
1274: {
1275: KSP ksp;
1277: PetscFunctionBegin;
1279: PetscCall(SNESGetKSP(snes, &ksp));
1280: PetscCall(KSPSetApplicationContext(ksp, ctx));
1281: snes->ctx = ctx;
1282: PetscFunctionReturn(PETSC_SUCCESS);
1283: }
1285: /*@
1286: SNESGetApplicationContext - Gets the user-defined context for the
1287: nonlinear solvers set with `SNESGetApplicationContext()` or `SNESSetComputeApplicationContext()`
1289: Not Collective
1291: Input Parameter:
1292: . snes - `SNES` context
1294: Output Parameter:
1295: . ctx - user context
1297: Level: intermediate
1299: Fortran Notes:
1300: 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
1301: function that tells the Fortran compiler the derived data type that is returned as the `ctx` argument. For example,
1302: .vb
1303: Interface SNESGetApplicationContext
1304: Subroutine SNESGetApplicationContext(snes,ctx,ierr)
1305: #include <petsc/finclude/petscsnes.h>
1306: use petscsnes
1307: SNES snes
1308: type(tUsertype), pointer :: ctx
1309: PetscErrorCode ierr
1310: End Subroutine
1311: End Interface SNESGetApplicationContext
1312: .ve
1314: The prototype for `ctx` must be
1315: .vb
1316: type(tUsertype), pointer :: ctx
1317: .ve
1319: .seealso: [](ch_snes), `SNESSetApplicationContext()`, `SNESSetComputeApplicationContext()`
1320: @*/
1321: PetscErrorCode SNESGetApplicationContext(SNES snes, PeCtx ctx)
1322: {
1323: PetscFunctionBegin;
1325: *(void **)ctx = snes->ctx;
1326: PetscFunctionReturn(PETSC_SUCCESS);
1327: }
1329: /*@
1330: SNESSetUseMatrixFree - indicates that `SNES` should use matrix-free finite difference matrix-vector products to apply the Jacobian.
1332: Logically Collective
1334: Input Parameters:
1335: + snes - `SNES` context
1336: . mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1337: - 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
1338: this option no matrix-element based preconditioners can be used in the linear solve since the matrix won't be explicitly available
1340: Options Database Keys:
1341: + -snes_mf_operator - use matrix-free only for the mat operator
1342: . -snes_mf - use matrix-free for both the mat and pmat operator
1343: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1344: - -snes_fd - compute the Jacobian via finite differences (slow)
1346: Level: intermediate
1348: Note:
1349: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
1350: and computing explicitly with
1351: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
1353: .seealso: [](ch_snes), `SNES`, `SNESGetUseMatrixFree()`, `MatCreateSNESMF()`, `SNESComputeJacobianDefaultColor()`, `MatFDColoring`
1354: @*/
1355: PetscErrorCode SNESSetUseMatrixFree(SNES snes, PetscBool mf_operator, PetscBool mf)
1356: {
1357: PetscFunctionBegin;
1361: snes->mf = mf_operator ? PETSC_TRUE : mf;
1362: snes->mf_operator = mf_operator;
1363: PetscFunctionReturn(PETSC_SUCCESS);
1364: }
1366: /*@
1367: SNESGetUseMatrixFree - indicates if the `SNES` uses matrix-free finite difference matrix vector products to apply the Jacobian.
1369: Not Collective, but the resulting flags will be the same on all MPI processes
1371: Input Parameter:
1372: . snes - `SNES` context
1374: Output Parameters:
1375: + mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1376: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored
1378: Level: intermediate
1380: .seealso: [](ch_snes), `SNES`, `SNESSetUseMatrixFree()`, `MatCreateSNESMF()`
1381: @*/
1382: PetscErrorCode SNESGetUseMatrixFree(SNES snes, PetscBool *mf_operator, PetscBool *mf)
1383: {
1384: PetscFunctionBegin;
1386: if (mf) *mf = snes->mf;
1387: if (mf_operator) *mf_operator = snes->mf_operator;
1388: PetscFunctionReturn(PETSC_SUCCESS);
1389: }
1391: /*@
1392: SNESGetIterationNumber - Gets the number of nonlinear iterations completed in the current or most recent `SNESSolve()`
1394: Not Collective
1396: Input Parameter:
1397: . snes - `SNES` context
1399: Output Parameter:
1400: . iter - iteration number
1402: Level: intermediate
1404: Notes:
1405: For example, during the computation of iteration 2 this would return 1.
1407: This is useful for using lagged Jacobians (where one does not recompute the
1408: Jacobian at each `SNES` iteration). For example, the code
1409: .vb
1410: ierr = SNESGetIterationNumber(snes,&it);
1411: if (!(it % 2)) {
1412: [compute Jacobian here]
1413: }
1414: .ve
1415: can be used in your function that computes the Jacobian to cause the Jacobian to be
1416: recomputed every second `SNES` iteration. See also `SNESSetLagJacobian()`
1418: After the `SNES` solve is complete this will return the number of nonlinear iterations used.
1420: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetLagJacobian()`, `SNESGetLinearSolveIterations()`, `SNESSetMonitor()`
1421: @*/
1422: PetscErrorCode SNESGetIterationNumber(SNES snes, PetscInt *iter)
1423: {
1424: PetscFunctionBegin;
1426: PetscAssertPointer(iter, 2);
1427: *iter = snes->iter;
1428: PetscFunctionReturn(PETSC_SUCCESS);
1429: }
1431: /*@
1432: SNESSetIterationNumber - Sets the current iteration number.
1434: Not Collective
1436: Input Parameters:
1437: + snes - `SNES` context
1438: - iter - iteration number
1440: Level: developer
1442: Note:
1443: This should only be called inside a `SNES` nonlinear solver.
1445: .seealso: [](ch_snes), `SNESGetLinearSolveIterations()`
1446: @*/
1447: PetscErrorCode SNESSetIterationNumber(SNES snes, PetscInt iter)
1448: {
1449: PetscFunctionBegin;
1451: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
1452: snes->iter = iter;
1453: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
1454: PetscFunctionReturn(PETSC_SUCCESS);
1455: }
1457: /*@
1458: SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1459: attempted by the nonlinear solver in the current or most recent `SNESSolve()` .
1461: Not Collective
1463: Input Parameter:
1464: . snes - `SNES` context
1466: Output Parameter:
1467: . nfails - number of unsuccessful steps attempted
1469: Level: intermediate
1471: Note:
1472: This counter is reset to zero for each successive call to `SNESSolve()`.
1474: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1475: `SNESSetMaxNonlinearStepFailures()`, `SNESGetMaxNonlinearStepFailures()`
1476: @*/
1477: PetscErrorCode SNESGetNonlinearStepFailures(SNES snes, PetscInt *nfails)
1478: {
1479: PetscFunctionBegin;
1481: PetscAssertPointer(nfails, 2);
1482: *nfails = snes->numFailures;
1483: PetscFunctionReturn(PETSC_SUCCESS);
1484: }
1486: /*@
1487: SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1488: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1490: Not Collective
1492: Input Parameters:
1493: + snes - `SNES` context
1494: - maxFails - maximum of unsuccessful steps allowed, use `PETSC_UNLIMITED` to have no limit on the number of failures
1496: Options Database Key:
1497: . -snes_max_fail <n> - maximum number of unsuccessful steps allowed
1499: Level: intermediate
1501: Developer Note:
1502: The options database key is wrong for this function name
1504: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1505: `SNESGetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1506: @*/
1507: PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1508: {
1509: PetscFunctionBegin;
1512: if (maxFails == PETSC_UNLIMITED) {
1513: snes->maxFailures = PETSC_INT_MAX;
1514: } else {
1515: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1516: snes->maxFailures = maxFails;
1517: }
1518: PetscFunctionReturn(PETSC_SUCCESS);
1519: }
1521: /*@
1522: SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1523: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1525: Not Collective
1527: Input Parameter:
1528: . snes - `SNES` context
1530: Output Parameter:
1531: . maxFails - maximum of unsuccessful steps
1533: Level: intermediate
1535: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1536: `SNESSetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1537: @*/
1538: PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1539: {
1540: PetscFunctionBegin;
1542: PetscAssertPointer(maxFails, 2);
1543: *maxFails = snes->maxFailures;
1544: PetscFunctionReturn(PETSC_SUCCESS);
1545: }
1547: /*@
1548: SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1549: done by the `SNES` object in the current or most recent `SNESSolve()`
1551: Not Collective
1553: Input Parameter:
1554: . snes - `SNES` context
1556: Output Parameter:
1557: . nfuncs - number of evaluations
1559: Level: intermediate
1561: Note:
1562: Reset every time `SNESSolve()` is called unless `SNESSetCountersReset()` is used.
1564: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`, `SNESSetCountersReset()`
1565: @*/
1566: PetscErrorCode SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1567: {
1568: PetscFunctionBegin;
1570: PetscAssertPointer(nfuncs, 2);
1571: *nfuncs = snes->nfuncs;
1572: PetscFunctionReturn(PETSC_SUCCESS);
1573: }
1575: /*@
1576: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1577: linear solvers in the current or most recent `SNESSolve()`
1579: Not Collective
1581: Input Parameter:
1582: . snes - `SNES` context
1584: Output Parameter:
1585: . nfails - number of failed solves
1587: Options Database Key:
1588: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1590: Level: intermediate
1592: Note:
1593: This counter is reset to zero for each successive call to `SNESSolve()`.
1595: .seealso: [](ch_snes), `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1596: @*/
1597: PetscErrorCode SNESGetLinearSolveFailures(SNES snes, PetscInt *nfails)
1598: {
1599: PetscFunctionBegin;
1601: PetscAssertPointer(nfails, 2);
1602: *nfails = snes->numLinearSolveFailures;
1603: PetscFunctionReturn(PETSC_SUCCESS);
1604: }
1606: /*@
1607: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1608: allowed before `SNES` returns with a diverged reason of `SNES_DIVERGED_LINEAR_SOLVE`
1610: Logically Collective
1612: Input Parameters:
1613: + snes - `SNES` context
1614: - maxFails - maximum allowed linear solve failures, use `PETSC_UNLIMITED` to have no limit on the number of failures
1616: Options Database Key:
1617: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1619: Level: intermediate
1621: Note:
1622: By default this is 0; that is `SNES` returns on the first failed linear solve
1624: Developer Note:
1625: The options database key is wrong for this function name
1627: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`
1628: @*/
1629: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1630: {
1631: PetscFunctionBegin;
1635: if (maxFails == PETSC_UNLIMITED) {
1636: snes->maxLinearSolveFailures = PETSC_INT_MAX;
1637: } else {
1638: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1639: snes->maxLinearSolveFailures = maxFails;
1640: }
1641: PetscFunctionReturn(PETSC_SUCCESS);
1642: }
1644: /*@
1645: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1646: are allowed before `SNES` returns as unsuccessful
1648: Not Collective
1650: Input Parameter:
1651: . snes - `SNES` context
1653: Output Parameter:
1654: . maxFails - maximum of unsuccessful solves allowed
1656: Level: intermediate
1658: Note:
1659: By default this is 1; that is `SNES` returns on the first failed linear solve
1661: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`,
1662: @*/
1663: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1664: {
1665: PetscFunctionBegin;
1667: PetscAssertPointer(maxFails, 2);
1668: *maxFails = snes->maxLinearSolveFailures;
1669: PetscFunctionReturn(PETSC_SUCCESS);
1670: }
1672: /*@
1673: SNESGetLinearSolveIterations - Gets the total number of linear iterations
1674: used by the nonlinear solver in the most recent `SNESSolve()`
1676: Not Collective
1678: Input Parameter:
1679: . snes - `SNES` context
1681: Output Parameter:
1682: . lits - number of linear iterations
1684: Level: intermediate
1686: Notes:
1687: This counter is reset to zero for each successive call to `SNESSolve()` unless `SNESSetCountersReset()` is used.
1689: 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
1690: then call `KSPGetIterationNumber()` after the failed solve.
1692: .seealso: [](ch_snes), `SNES`, `SNESGetIterationNumber()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESSetCountersReset()`
1693: @*/
1694: PetscErrorCode SNESGetLinearSolveIterations(SNES snes, PetscInt *lits)
1695: {
1696: PetscFunctionBegin;
1698: PetscAssertPointer(lits, 2);
1699: *lits = snes->linear_its;
1700: PetscFunctionReturn(PETSC_SUCCESS);
1701: }
1703: /*@
1704: SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1705: are reset every time `SNESSolve()` is called.
1707: Logically Collective
1709: Input Parameters:
1710: + snes - `SNES` context
1711: - reset - whether to reset the counters or not, defaults to `PETSC_TRUE`
1713: Level: developer
1715: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1716: @*/
1717: PetscErrorCode SNESSetCountersReset(SNES snes, PetscBool reset)
1718: {
1719: PetscFunctionBegin;
1722: snes->counters_reset = reset;
1723: PetscFunctionReturn(PETSC_SUCCESS);
1724: }
1726: /*@
1727: SNESResetCounters - Reset counters for linear iterations and function evaluations.
1729: Logically Collective
1731: Input Parameters:
1732: . snes - `SNES` context
1734: Level: developer
1736: Note:
1737: It honors the flag set with `SNESSetCountersReset()`
1739: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1740: @*/
1741: PetscErrorCode SNESResetCounters(SNES snes)
1742: {
1743: PetscFunctionBegin;
1745: if (snes->counters_reset) {
1746: snes->nfuncs = 0;
1747: snes->linear_its = 0;
1748: snes->numFailures = 0;
1749: }
1750: PetscFunctionReturn(PETSC_SUCCESS);
1751: }
1753: /*@
1754: SNESSetKSP - Sets a `KSP` context for the `SNES` object to use
1756: Not Collective, but the `SNES` and `KSP` objects must live on the same `MPI_Comm`
1758: Input Parameters:
1759: + snes - the `SNES` context
1760: - ksp - the `KSP` context
1762: Level: developer
1764: Notes:
1765: The `SNES` object already has its `KSP` object, you can obtain with `SNESGetKSP()`
1766: so this routine is rarely needed.
1768: The `KSP` object that is already in the `SNES` object has its reference count
1769: decreased by one when this is called.
1771: .seealso: [](ch_snes), `SNES`, `KSP`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`
1772: @*/
1773: PetscErrorCode SNESSetKSP(SNES snes, KSP ksp)
1774: {
1775: PetscFunctionBegin;
1778: PetscCheckSameComm(snes, 1, ksp, 2);
1779: PetscCall(PetscObjectReference((PetscObject)ksp));
1780: if (snes->ksp) PetscCall(PetscObjectDereference((PetscObject)snes->ksp));
1781: snes->ksp = ksp;
1782: PetscFunctionReturn(PETSC_SUCCESS);
1783: }
1785: /*@
1786: SNESParametersInitialize - Sets all the parameters in `snes` to their default value (when `SNESCreate()` was called) if they
1787: currently contain default values
1789: Collective
1791: Input Parameter:
1792: . snes - the `SNES` object
1794: Level: developer
1796: Developer Note:
1797: This is called by all the `SNESCreate_XXX()` routines.
1799: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`,
1800: `PetscObjectParameterSetDefault()`
1801: @*/
1802: PetscErrorCode SNESParametersInitialize(SNES snes)
1803: {
1804: PetscObjectParameterSetDefault(snes, max_its, 50);
1805: PetscObjectParameterSetDefault(snes, max_funcs, 10000);
1806: PetscObjectParameterSetDefault(snes, rtol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1807: PetscObjectParameterSetDefault(snes, abstol, PetscDefined(USE_REAL_SINGLE) ? 1.e-25 : 1.e-50);
1808: PetscObjectParameterSetDefault(snes, stol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1809: PetscObjectParameterSetDefault(snes, divtol, 1.e4);
1810: return PETSC_SUCCESS;
1811: }
1813: /*@
1814: SNESCreate - Creates a nonlinear solver context used to manage a set of nonlinear solves
1816: Collective
1818: Input Parameter:
1819: . comm - MPI communicator
1821: Output Parameter:
1822: . outsnes - the new `SNES` context
1824: Options Database Keys:
1825: + -snes_mf - Activates default matrix-free Jacobian-vector products, and no matrix to construct a preconditioner
1826: . -snes_mf_operator - Activates default matrix-free Jacobian-vector products, and a user-provided matrix as set by `SNESSetJacobian()`
1827: . -snes_fd_coloring - uses a relative fast computation of the Jacobian using finite differences and a graph coloring
1828: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
1830: Level: beginner
1832: Developer Notes:
1833: `SNES` always creates a `KSP` object even though many `SNES` methods do not use it. This is
1834: unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1835: particular method does use `KSP` and regulates if the information about the `KSP` is printed
1836: in `SNESView()`.
1838: `TSSetFromOptions()` does call `SNESSetFromOptions()` which can lead to users being confused
1839: by help messages about meaningless `SNES` options.
1841: `SNES` always creates the `snes->kspconvctx` even though it is used by only one type. This should be fixed.
1843: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
1844: @*/
1845: PetscErrorCode SNESCreate(MPI_Comm comm, SNES *outsnes)
1846: {
1847: SNES snes;
1848: SNESKSPEW *kctx;
1850: PetscFunctionBegin;
1851: PetscAssertPointer(outsnes, 2);
1852: PetscCall(SNESInitializePackage());
1854: PetscCall(PetscHeaderCreate(snes, SNES_CLASSID, "SNES", "Nonlinear solver", "SNES", comm, SNESDestroy, SNESView));
1855: snes->ops->converged = SNESConvergedDefault;
1856: snes->usesksp = PETSC_TRUE;
1857: snes->norm = 0.0;
1858: snes->xnorm = 0.0;
1859: snes->ynorm = 0.0;
1860: snes->normschedule = SNES_NORM_ALWAYS;
1861: snes->functype = SNES_FUNCTION_DEFAULT;
1862: snes->ttol = 0.0;
1864: snes->rnorm0 = 0;
1865: snes->nfuncs = 0;
1866: snes->numFailures = 0;
1867: snes->maxFailures = 1;
1868: snes->linear_its = 0;
1869: snes->lagjacobian = 1;
1870: snes->jac_iter = 0;
1871: snes->lagjac_persist = PETSC_FALSE;
1872: snes->lagpreconditioner = 1;
1873: snes->pre_iter = 0;
1874: snes->lagpre_persist = PETSC_FALSE;
1875: snes->numbermonitors = 0;
1876: snes->numberreasonviews = 0;
1877: snes->data = NULL;
1878: snes->setupcalled = PETSC_FALSE;
1879: snes->ksp_ewconv = PETSC_FALSE;
1880: snes->nwork = 0;
1881: snes->work = NULL;
1882: snes->nvwork = 0;
1883: snes->vwork = NULL;
1884: snes->conv_hist_len = 0;
1885: snes->conv_hist_max = 0;
1886: snes->conv_hist = NULL;
1887: snes->conv_hist_its = NULL;
1888: snes->conv_hist_reset = PETSC_TRUE;
1889: snes->counters_reset = PETSC_TRUE;
1890: snes->vec_func_init_set = PETSC_FALSE;
1891: snes->reason = SNES_CONVERGED_ITERATING;
1892: snes->npcside = PC_RIGHT;
1893: snes->setfromoptionscalled = 0;
1895: snes->mf = PETSC_FALSE;
1896: snes->mf_operator = PETSC_FALSE;
1897: snes->mf_version = 1;
1899: snes->numLinearSolveFailures = 0;
1900: snes->maxLinearSolveFailures = 1;
1902: snes->vizerotolerance = 1.e-8;
1903: snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;
1905: /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1906: snes->alwayscomputesfinalresidual = PETSC_FALSE;
1908: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1909: PetscCall(PetscNew(&kctx));
1911: snes->kspconvctx = kctx;
1912: kctx->version = 2;
1913: kctx->rtol_0 = 0.3; /* Eisenstat and Walker suggest rtol_0=.5, but
1914: this was too large for some test cases */
1915: kctx->rtol_last = 0.0;
1916: kctx->rtol_max = 0.9;
1917: kctx->gamma = 1.0;
1918: kctx->alpha = 0.5 * (1.0 + PetscSqrtReal(5.0));
1919: kctx->alpha2 = kctx->alpha;
1920: kctx->threshold = 0.1;
1921: kctx->lresid_last = 0.0;
1922: kctx->norm_last = 0.0;
1924: kctx->rk_last = 0.0;
1925: kctx->rk_last_2 = 0.0;
1926: kctx->rtol_last_2 = 0.0;
1927: kctx->v4_p1 = 0.1;
1928: kctx->v4_p2 = 0.4;
1929: kctx->v4_p3 = 0.7;
1930: kctx->v4_m1 = 0.8;
1931: kctx->v4_m2 = 0.5;
1932: kctx->v4_m3 = 0.1;
1933: kctx->v4_m4 = 0.5;
1935: PetscCall(SNESParametersInitialize(snes));
1936: *outsnes = snes;
1937: PetscFunctionReturn(PETSC_SUCCESS);
1938: }
1940: /*@C
1941: SNESSetFunction - Sets the function evaluation routine and function
1942: vector for use by the `SNES` routines in solving systems of nonlinear
1943: equations.
1945: Logically Collective
1947: Input Parameters:
1948: + snes - the `SNES` context
1949: . r - vector to store function values, may be `NULL`
1950: . f - function evaluation routine; for calling sequence see `SNESFunctionFn`
1951: - ctx - [optional] user-defined context for private data for the
1952: function evaluation routine (may be `NULL`)
1954: Level: beginner
1956: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetPicard()`, `SNESFunctionFn`
1957: @*/
1958: PetscErrorCode SNESSetFunction(SNES snes, Vec r, SNESFunctionFn *f, void *ctx)
1959: {
1960: DM dm;
1962: PetscFunctionBegin;
1964: if (r) {
1966: PetscCheckSameComm(snes, 1, r, 2);
1967: PetscCall(PetscObjectReference((PetscObject)r));
1968: PetscCall(VecDestroy(&snes->vec_func));
1969: snes->vec_func = r;
1970: }
1971: PetscCall(SNESGetDM(snes, &dm));
1972: PetscCall(DMSNESSetFunction(dm, f, ctx));
1973: if (f == SNESPicardComputeFunction) PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
1974: PetscFunctionReturn(PETSC_SUCCESS);
1975: }
1977: /*@C
1978: SNESSetInitialFunction - Set an already computed function evaluation at the initial guess to be reused by `SNESSolve()`.
1980: Logically Collective
1982: Input Parameters:
1983: + snes - the `SNES` context
1984: - f - vector to store function value
1986: Level: developer
1988: Notes:
1989: This should not be modified during the solution procedure.
1991: This is used extensively in the `SNESFAS` hierarchy and in nonlinear preconditioning.
1993: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetInitialFunctionNorm()`
1994: @*/
1995: PetscErrorCode SNESSetInitialFunction(SNES snes, Vec f)
1996: {
1997: Vec vec_func;
1999: PetscFunctionBegin;
2002: PetscCheckSameComm(snes, 1, f, 2);
2003: if (snes->npcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
2004: snes->vec_func_init_set = PETSC_FALSE;
2005: PetscFunctionReturn(PETSC_SUCCESS);
2006: }
2007: PetscCall(SNESGetFunction(snes, &vec_func, NULL, NULL));
2008: PetscCall(VecCopy(f, vec_func));
2010: snes->vec_func_init_set = PETSC_TRUE;
2011: PetscFunctionReturn(PETSC_SUCCESS);
2012: }
2014: /*@
2015: SNESSetNormSchedule - Sets the `SNESNormSchedule` used in convergence and monitoring
2016: of the `SNES` method, when norms are computed in the solving process
2018: Logically Collective
2020: Input Parameters:
2021: + snes - the `SNES` context
2022: - normschedule - the frequency of norm computation
2024: Options Database Key:
2025: . -snes_norm_schedule <none, always, initialonly, finalonly, initialfinalonly> - set the schedule
2027: Level: advanced
2029: Notes:
2030: Only certain `SNES` methods support certain `SNESNormSchedules`. Most require evaluation
2031: of the nonlinear function and the taking of its norm at every iteration to
2032: even ensure convergence at all. However, methods such as custom Gauss-Seidel methods
2033: `SNESNGS` and the like do not require the norm of the function to be computed, and therefore
2034: may either be monitored for convergence or not. As these are often used as nonlinear
2035: preconditioners, monitoring the norm of their error is not a useful enterprise within
2036: their solution.
2038: .seealso: [](ch_snes), `SNESNormSchedule`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`
2039: @*/
2040: PetscErrorCode SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
2041: {
2042: PetscFunctionBegin;
2044: snes->normschedule = normschedule;
2045: PetscFunctionReturn(PETSC_SUCCESS);
2046: }
2048: /*@
2049: SNESGetNormSchedule - Gets the `SNESNormSchedule` used in convergence and monitoring
2050: of the `SNES` method.
2052: Logically Collective
2054: Input Parameters:
2055: + snes - the `SNES` context
2056: - normschedule - the type of the norm used
2058: Level: advanced
2060: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2061: @*/
2062: PetscErrorCode SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
2063: {
2064: PetscFunctionBegin;
2066: *normschedule = snes->normschedule;
2067: PetscFunctionReturn(PETSC_SUCCESS);
2068: }
2070: /*@
2071: SNESSetFunctionNorm - Sets the last computed residual norm.
2073: Logically Collective
2075: Input Parameters:
2076: + snes - the `SNES` context
2077: - norm - the value of the norm
2079: Level: developer
2081: .seealso: [](ch_snes), `SNES`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2082: @*/
2083: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
2084: {
2085: PetscFunctionBegin;
2087: snes->norm = norm;
2088: PetscFunctionReturn(PETSC_SUCCESS);
2089: }
2091: /*@
2092: SNESGetFunctionNorm - Gets the last computed norm of the residual
2094: Not Collective
2096: Input Parameter:
2097: . snes - the `SNES` context
2099: Output Parameter:
2100: . norm - the last computed residual norm
2102: Level: developer
2104: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2105: @*/
2106: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
2107: {
2108: PetscFunctionBegin;
2110: PetscAssertPointer(norm, 2);
2111: *norm = snes->norm;
2112: PetscFunctionReturn(PETSC_SUCCESS);
2113: }
2115: /*@
2116: SNESGetUpdateNorm - Gets the last computed norm of the solution update
2118: Not Collective
2120: Input Parameter:
2121: . snes - the `SNES` context
2123: Output Parameter:
2124: . ynorm - the last computed update norm
2126: Level: developer
2128: Note:
2129: The new solution is the current solution plus the update, so this norm is an indication of the size of the update
2131: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`
2132: @*/
2133: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2134: {
2135: PetscFunctionBegin;
2137: PetscAssertPointer(ynorm, 2);
2138: *ynorm = snes->ynorm;
2139: PetscFunctionReturn(PETSC_SUCCESS);
2140: }
2142: /*@
2143: SNESGetSolutionNorm - Gets the last computed norm of the solution
2145: Not Collective
2147: Input Parameter:
2148: . snes - the `SNES` context
2150: Output Parameter:
2151: . xnorm - the last computed solution norm
2153: Level: developer
2155: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`, `SNESGetUpdateNorm()`
2156: @*/
2157: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2158: {
2159: PetscFunctionBegin;
2161: PetscAssertPointer(xnorm, 2);
2162: *xnorm = snes->xnorm;
2163: PetscFunctionReturn(PETSC_SUCCESS);
2164: }
2166: /*@
2167: SNESSetFunctionType - Sets the `SNESFunctionType`
2168: of the `SNES` method.
2170: Logically Collective
2172: Input Parameters:
2173: + snes - the `SNES` context
2174: - type - the function type
2176: Level: developer
2178: Values of the function type\:
2179: + `SNES_FUNCTION_DEFAULT` - the default for the given `SNESType`
2180: . `SNES_FUNCTION_UNPRECONDITIONED` - an unpreconditioned function evaluation (this is the function provided with `SNESSetFunction()`
2181: - `SNES_FUNCTION_PRECONDITIONED` - a transformation of the function provided with `SNESSetFunction()`
2183: Note:
2184: Different `SNESType`s use this value in different ways
2186: .seealso: [](ch_snes), `SNES`, `SNESFunctionType`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2187: @*/
2188: PetscErrorCode SNESSetFunctionType(SNES snes, SNESFunctionType type)
2189: {
2190: PetscFunctionBegin;
2192: snes->functype = type;
2193: PetscFunctionReturn(PETSC_SUCCESS);
2194: }
2196: /*@
2197: SNESGetFunctionType - Gets the `SNESFunctionType` used in convergence and monitoring set with `SNESSetFunctionType()`
2198: of the SNES method.
2200: Logically Collective
2202: Input Parameters:
2203: + snes - the `SNES` context
2204: - type - the type of the function evaluation, see `SNESSetFunctionType()`
2206: Level: advanced
2208: .seealso: [](ch_snes), `SNESSetFunctionType()`, `SNESFunctionType`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2209: @*/
2210: PetscErrorCode SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2211: {
2212: PetscFunctionBegin;
2214: *type = snes->functype;
2215: PetscFunctionReturn(PETSC_SUCCESS);
2216: }
2218: /*@C
2219: SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2220: use with composed nonlinear solvers.
2222: Input Parameters:
2223: + snes - the `SNES` context, usually of the `SNESType` `SNESNGS`
2224: . f - function evaluation routine to apply Gauss-Seidel, see `SNESNGSFn` for calling sequence
2225: - ctx - [optional] user-defined context for private data for the smoother evaluation routine (may be `NULL`)
2227: Level: intermediate
2229: Note:
2230: The `SNESNGS` routines are used by the composed nonlinear solver to generate
2231: a problem appropriate update to the solution, particularly `SNESFAS`.
2233: .seealso: [](ch_snes), `SNESNGS`, `SNESGetNGS()`, `SNESNCG`, `SNESGetFunction()`, `SNESComputeNGS()`, `SNESNGSFn`
2234: @*/
2235: PetscErrorCode SNESSetNGS(SNES snes, SNESNGSFn *f, void *ctx)
2236: {
2237: DM dm;
2239: PetscFunctionBegin;
2241: PetscCall(SNESGetDM(snes, &dm));
2242: PetscCall(DMSNESSetNGS(dm, f, ctx));
2243: PetscFunctionReturn(PETSC_SUCCESS);
2244: }
2246: /*
2247: This is used for -snes_mf_operator; it uses a duplicate of snes->jacobian_pre because snes->jacobian_pre cannot be
2248: changed during the KSPSolve()
2249: */
2250: PetscErrorCode SNESPicardComputeMFFunction(SNES snes, Vec x, Vec f, void *ctx)
2251: {
2252: DM dm;
2253: DMSNES sdm;
2255: PetscFunctionBegin;
2256: PetscCall(SNESGetDM(snes, &dm));
2257: PetscCall(DMGetDMSNES(dm, &sdm));
2258: /* A(x)*x - b(x) */
2259: if (sdm->ops->computepfunction) {
2260: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2261: PetscCall(VecScale(f, -1.0));
2262: /* Cannot share nonzero pattern because of the possible use of SNESComputeJacobianDefault() */
2263: if (!snes->picard) PetscCall(MatDuplicate(snes->jacobian_pre, MAT_DO_NOT_COPY_VALUES, &snes->picard));
2264: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2265: PetscCall(MatMultAdd(snes->picard, x, f, f));
2266: } else {
2267: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2268: PetscCall(MatMult(snes->picard, x, f));
2269: }
2270: PetscFunctionReturn(PETSC_SUCCESS);
2271: }
2273: PetscErrorCode SNESPicardComputeFunction(SNES snes, Vec x, Vec f, void *ctx)
2274: {
2275: DM dm;
2276: DMSNES sdm;
2278: PetscFunctionBegin;
2279: PetscCall(SNESGetDM(snes, &dm));
2280: PetscCall(DMGetDMSNES(dm, &sdm));
2281: /* A(x)*x - b(x) */
2282: if (sdm->ops->computepfunction) {
2283: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2284: PetscCall(VecScale(f, -1.0));
2285: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2286: PetscCall(MatMultAdd(snes->jacobian_pre, x, f, f));
2287: } else {
2288: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2289: PetscCall(MatMult(snes->jacobian_pre, x, f));
2290: }
2291: PetscFunctionReturn(PETSC_SUCCESS);
2292: }
2294: PetscErrorCode SNESPicardComputeJacobian(SNES snes, Vec x1, Mat J, Mat B, void *ctx)
2295: {
2296: PetscFunctionBegin;
2297: /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2298: /* must assembly if matrix-free to get the last SNES solution */
2299: PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
2300: PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
2301: PetscFunctionReturn(PETSC_SUCCESS);
2302: }
2304: /*@C
2305: SNESSetPicard - Use `SNES` to solve the system $A(x) x = bp(x) + b $ via a Picard type iteration (Picard linearization)
2307: Logically Collective
2309: Input Parameters:
2310: + snes - the `SNES` context
2311: . r - vector to store function values, may be `NULL`
2312: . bp - function evaluation routine, may be `NULL`, for the calling sequence see `SNESFunctionFn`
2313: . Amat - matrix with which $A(x) x - bp(x) - b$ is to be computed
2314: . Pmat - matrix from which preconditioner is computed (usually the same as `Amat`)
2315: . J - function to compute matrix values, for the calling sequence see `SNESJacobianFn`
2316: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
2318: Level: intermediate
2320: Notes:
2321: It is often better to provide the nonlinear function $F()$ and some approximation to its Jacobian directly and use
2322: 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.
2324: One can call `SNESSetPicard()` or `SNESSetFunction()` (and possibly `SNESSetJacobian()`) but cannot call both
2326: Solves the equation $A(x) x = bp(x) - b$ via the defect correction algorithm $A(x^{n}) (x^{n+1} - x^{n}) = bp(x^{n}) + b - A(x^{n})x^{n}$.
2327: When an exact solver is used this corresponds to the "classic" Picard $A(x^{n}) x^{n+1} = bp(x^{n}) + b$ iteration.
2329: Run with `-snes_mf_operator` to solve the system with Newton's method using $A(x^{n})$ to construct the preconditioner.
2331: We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2332: the direct Picard iteration $A(x^n) x^{n+1} = bp(x^n) + b$
2334: 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
2335: 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
2336: different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument \:-).
2338: 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
2339: $A(x^{n})$ is used to build the preconditioner
2341: When used with `-snes_fd` this will compute the true Jacobian (very slowly one column at a time) and thus represent Newton's method.
2343: 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
2344: 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
2345: 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`.
2346: See the comment in src/snes/tutorials/ex15.c.
2348: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESGetPicard()`, `SNESLineSearchPreCheckPicard()`,
2349: `SNESFunctionFn`, `SNESJacobianFn`
2350: @*/
2351: PetscErrorCode SNESSetPicard(SNES snes, Vec r, SNESFunctionFn *bp, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
2352: {
2353: DM dm;
2355: PetscFunctionBegin;
2357: PetscCall(SNESGetDM(snes, &dm));
2358: PetscCall(DMSNESSetPicard(dm, bp, J, ctx));
2359: PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2360: PetscCall(SNESSetFunction(snes, r, SNESPicardComputeFunction, ctx));
2361: PetscCall(SNESSetJacobian(snes, Amat, Pmat, SNESPicardComputeJacobian, ctx));
2362: PetscFunctionReturn(PETSC_SUCCESS);
2363: }
2365: /*@C
2366: SNESGetPicard - Returns the context for the Picard iteration
2368: Not Collective, but `Vec` is parallel if `SNES` is parallel. Collective if `Vec` is requested, but has not been created yet.
2370: Input Parameter:
2371: . snes - the `SNES` context
2373: Output Parameters:
2374: + r - the function (or `NULL`)
2375: . f - the function (or `NULL`); for calling sequence see `SNESFunctionFn`
2376: . Amat - the matrix used to defined the operation A(x) x - b(x) (or `NULL`)
2377: . Pmat - the matrix from which the preconditioner will be constructed (or `NULL`)
2378: . J - the function for matrix evaluation (or `NULL`); for calling sequence see `SNESJacobianFn`
2379: - ctx - the function context (or `NULL`)
2381: Level: advanced
2383: .seealso: [](ch_snes), `SNESSetFunction()`, `SNESSetPicard()`, `SNESGetFunction()`, `SNESGetJacobian()`, `SNESGetDM()`, `SNESFunctionFn`, `SNESJacobianFn`
2384: @*/
2385: PetscErrorCode SNESGetPicard(SNES snes, Vec *r, SNESFunctionFn **f, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
2386: {
2387: DM dm;
2389: PetscFunctionBegin;
2391: PetscCall(SNESGetFunction(snes, r, NULL, NULL));
2392: PetscCall(SNESGetJacobian(snes, Amat, Pmat, NULL, NULL));
2393: PetscCall(SNESGetDM(snes, &dm));
2394: PetscCall(DMSNESGetPicard(dm, f, J, ctx));
2395: PetscFunctionReturn(PETSC_SUCCESS);
2396: }
2398: /*@C
2399: SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the nonlinear problem
2401: Logically Collective
2403: Input Parameters:
2404: + snes - the `SNES` context
2405: . func - function evaluation routine, see `SNESInitialGuessFn` for the calling sequence
2406: - ctx - [optional] user-defined context for private data for the
2407: function evaluation routine (may be `NULL`)
2409: Level: intermediate
2411: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESInitialGuessFn`
2412: @*/
2413: PetscErrorCode SNESSetComputeInitialGuess(SNES snes, SNESInitialGuessFn *func, void *ctx)
2414: {
2415: PetscFunctionBegin;
2417: if (func) snes->ops->computeinitialguess = func;
2418: if (ctx) snes->initialguessP = ctx;
2419: PetscFunctionReturn(PETSC_SUCCESS);
2420: }
2422: /*@C
2423: SNESGetRhs - Gets the vector for solving F(x) = `rhs`. If `rhs` is not set
2424: it assumes a zero right-hand side.
2426: Logically Collective
2428: Input Parameter:
2429: . snes - the `SNES` context
2431: Output Parameter:
2432: . rhs - the right-hand side vector or `NULL` if there is no right-hand side vector
2434: Level: intermediate
2436: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetFunction()`
2437: @*/
2438: PetscErrorCode SNESGetRhs(SNES snes, Vec *rhs)
2439: {
2440: PetscFunctionBegin;
2442: PetscAssertPointer(rhs, 2);
2443: *rhs = snes->vec_rhs;
2444: PetscFunctionReturn(PETSC_SUCCESS);
2445: }
2447: /*@
2448: SNESComputeFunction - Calls the function that has been set with `SNESSetFunction()`.
2450: Collective
2452: Input Parameters:
2453: + snes - the `SNES` context
2454: - x - input vector
2456: Output Parameter:
2457: . y - function vector, as set by `SNESSetFunction()`
2459: Level: developer
2461: Notes:
2462: `SNESComputeFunction()` is typically used within nonlinear solvers
2463: implementations, so users would not generally call this routine themselves.
2465: When solving for $F(x) = b$, this routine computes $y = F(x) - b$.
2467: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeMFFunction()`
2468: @*/
2469: PetscErrorCode SNESComputeFunction(SNES snes, Vec x, Vec y)
2470: {
2471: DM dm;
2472: DMSNES sdm;
2474: PetscFunctionBegin;
2478: PetscCheckSameComm(snes, 1, x, 2);
2479: PetscCheckSameComm(snes, 1, y, 3);
2480: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2482: PetscCall(SNESGetDM(snes, &dm));
2483: PetscCall(DMGetDMSNES(dm, &sdm));
2484: 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().");
2485: if (sdm->ops->computefunction) {
2486: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2487: PetscCall(VecLockReadPush(x));
2488: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2489: snes->domainerror = PETSC_FALSE;
2490: {
2491: void *ctx;
2492: SNESFunctionFn *computefunction;
2493: PetscCall(DMSNESGetFunction(dm, &computefunction, &ctx));
2494: PetscCallBack("SNES callback function", (*computefunction)(snes, x, y, ctx));
2495: }
2496: PetscCall(VecLockReadPop(x));
2497: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2498: } else /* if (snes->vec_rhs) */ {
2499: PetscCall(MatMult(snes->jacobian, x, y));
2500: }
2501: if (snes->vec_rhs) PetscCall(VecAXPY(y, -1.0, snes->vec_rhs));
2502: snes->nfuncs++;
2503: /*
2504: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2505: propagate the value to all processes
2506: */
2507: PetscCall(VecFlag(y, snes->domainerror));
2508: PetscFunctionReturn(PETSC_SUCCESS);
2509: }
2511: /*@
2512: SNESComputeMFFunction - Calls the function that has been set with `DMSNESSetMFFunction()`.
2514: Collective
2516: Input Parameters:
2517: + snes - the `SNES` context
2518: - x - input vector
2520: Output Parameter:
2521: . y - output vector
2523: Level: developer
2525: Notes:
2526: `SNESComputeMFFunction()` is used within the matrix-vector products called by the matrix created with `MatCreateSNESMF()`
2527: so users would not generally call this routine themselves.
2529: Since this function is intended for use with finite differencing it does not subtract the right-hand side vector provided with `SNESSolve()`
2530: while `SNESComputeFunction()` does. As such, this routine cannot be used with `MatMFFDSetBase()` with a provided F function value even if it applies the
2531: 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.
2533: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `MatCreateSNESMF()`, `DMSNESSetMFFunction()`
2534: @*/
2535: PetscErrorCode SNESComputeMFFunction(SNES snes, Vec x, Vec y)
2536: {
2537: DM dm;
2538: DMSNES sdm;
2540: PetscFunctionBegin;
2544: PetscCheckSameComm(snes, 1, x, 2);
2545: PetscCheckSameComm(snes, 1, y, 3);
2546: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2548: PetscCall(SNESGetDM(snes, &dm));
2549: PetscCall(DMGetDMSNES(dm, &sdm));
2550: PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2551: PetscCall(VecLockReadPush(x));
2552: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2553: snes->domainerror = PETSC_FALSE;
2554: PetscCallBack("SNES callback function", (*sdm->ops->computemffunction)(snes, x, y, sdm->mffunctionctx));
2555: PetscCall(VecLockReadPop(x));
2556: PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2557: snes->nfuncs++;
2558: /*
2559: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2560: propagate the value to all processes
2561: */
2562: PetscCall(VecFlag(y, snes->domainerror));
2563: PetscFunctionReturn(PETSC_SUCCESS);
2564: }
2566: /*@
2567: SNESComputeNGS - Calls the Gauss-Seidel function that has been set with `SNESSetNGS()`.
2569: Collective
2571: Input Parameters:
2572: + snes - the `SNES` context
2573: . x - input vector
2574: - b - rhs vector
2576: Output Parameter:
2577: . x - new solution vector
2579: Level: developer
2581: Note:
2582: `SNESComputeNGS()` is typically used within composed nonlinear solver
2583: implementations, so most users would not generally call this routine
2584: themselves.
2586: .seealso: [](ch_snes), `SNESNGSFn`, `SNESSetNGS()`, `SNESComputeFunction()`, `SNESNGS`
2587: @*/
2588: PetscErrorCode SNESComputeNGS(SNES snes, Vec b, Vec x)
2589: {
2590: DM dm;
2591: DMSNES sdm;
2593: PetscFunctionBegin;
2597: PetscCheckSameComm(snes, 1, x, 3);
2598: if (b) PetscCheckSameComm(snes, 1, b, 2);
2599: if (b) PetscCall(VecValidValues_Internal(b, 2, PETSC_TRUE));
2600: PetscCall(PetscLogEventBegin(SNES_NGSEval, snes, x, b, 0));
2601: PetscCall(SNESGetDM(snes, &dm));
2602: PetscCall(DMGetDMSNES(dm, &sdm));
2603: PetscCheck(sdm->ops->computegs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2604: if (b) PetscCall(VecLockReadPush(b));
2605: PetscCallBack("SNES callback NGS", (*sdm->ops->computegs)(snes, x, b, sdm->gsctx));
2606: if (b) PetscCall(VecLockReadPop(b));
2607: PetscCall(PetscLogEventEnd(SNES_NGSEval, snes, x, b, 0));
2608: PetscFunctionReturn(PETSC_SUCCESS);
2609: }
2611: static PetscErrorCode SNESComputeFunction_FD(SNES snes, Vec Xin, Vec G)
2612: {
2613: Vec X;
2614: PetscScalar *g;
2615: PetscReal f, f2;
2616: PetscInt low, high, N, i;
2617: PetscBool flg;
2618: PetscReal h = .5 * PETSC_SQRT_MACHINE_EPSILON;
2620: PetscFunctionBegin;
2621: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_fd_delta", &h, &flg));
2622: PetscCall(VecDuplicate(Xin, &X));
2623: PetscCall(VecCopy(Xin, X));
2624: PetscCall(VecGetSize(X, &N));
2625: PetscCall(VecGetOwnershipRange(X, &low, &high));
2626: PetscCall(VecSetOption(X, VEC_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE));
2627: PetscCall(VecGetArray(G, &g));
2628: for (i = 0; i < N; i++) {
2629: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2630: PetscCall(VecAssemblyBegin(X));
2631: PetscCall(VecAssemblyEnd(X));
2632: PetscCall(SNESComputeObjective(snes, X, &f));
2633: PetscCall(VecSetValue(X, i, 2.0 * h, ADD_VALUES));
2634: PetscCall(VecAssemblyBegin(X));
2635: PetscCall(VecAssemblyEnd(X));
2636: PetscCall(SNESComputeObjective(snes, X, &f2));
2637: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2638: PetscCall(VecAssemblyBegin(X));
2639: PetscCall(VecAssemblyEnd(X));
2640: if (i >= low && i < high) g[i - low] = (f2 - f) / (2.0 * h);
2641: }
2642: PetscCall(VecRestoreArray(G, &g));
2643: PetscCall(VecDestroy(&X));
2644: PetscFunctionReturn(PETSC_SUCCESS);
2645: }
2647: PetscErrorCode SNESTestFunction(SNES snes)
2648: {
2649: Vec x, g1, g2, g3;
2650: PetscBool complete_print = PETSC_FALSE, test = PETSC_FALSE;
2651: PetscReal hcnorm, fdnorm, hcmax, fdmax, diffmax, diffnorm;
2652: PetscScalar dot;
2653: MPI_Comm comm;
2654: PetscViewer viewer, mviewer;
2655: PetscViewerFormat format;
2656: PetscInt tabs;
2657: static PetscBool directionsprinted = PETSC_FALSE;
2658: SNESObjectiveFn *objective;
2660: PetscFunctionBegin;
2661: PetscCall(SNESGetObjective(snes, &objective, NULL));
2662: if (!objective) PetscFunctionReturn(PETSC_SUCCESS);
2664: PetscObjectOptionsBegin((PetscObject)snes);
2665: PetscCall(PetscOptionsName("-snes_test_function", "Compare hand-coded and finite difference function", "None", &test));
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();
2668: if (!test) {
2669: if (complete_print) PetscCall(PetscViewerDestroy(&mviewer));
2670: PetscFunctionReturn(PETSC_SUCCESS);
2671: }
2673: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2674: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2675: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2676: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2677: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Function -------------\n"));
2678: if (!complete_print && !directionsprinted) {
2679: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_function_view and optionally -snes_test_function <threshold> to show difference\n"));
2680: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference function entries greater than <threshold>.\n"));
2681: }
2682: if (!directionsprinted) {
2683: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Function, if (for double precision runs) ||F - Ffd||/||F|| is\n"));
2684: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Function is probably correct.\n"));
2685: directionsprinted = PETSC_TRUE;
2686: }
2687: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2689: PetscCall(SNESGetSolution(snes, &x));
2690: PetscCall(VecDuplicate(x, &g1));
2691: PetscCall(VecDuplicate(x, &g2));
2692: PetscCall(VecDuplicate(x, &g3));
2693: PetscCall(SNESComputeFunction(snes, x, g1));
2694: PetscCall(SNESComputeFunction_FD(snes, x, g2));
2696: PetscCall(VecNorm(g2, NORM_2, &fdnorm));
2697: PetscCall(VecNorm(g1, NORM_2, &hcnorm));
2698: PetscCall(VecNorm(g2, NORM_INFINITY, &fdmax));
2699: PetscCall(VecNorm(g1, NORM_INFINITY, &hcmax));
2700: PetscCall(VecDot(g1, g2, &dot));
2701: PetscCall(VecCopy(g1, g3));
2702: PetscCall(VecAXPY(g3, -1.0, g2));
2703: PetscCall(VecNorm(g3, NORM_2, &diffnorm));
2704: PetscCall(VecNorm(g3, NORM_INFINITY, &diffmax));
2705: PetscCall(PetscViewerASCIIPrintf(viewer, " ||Ffd|| %g, ||F|| = %g, angle cosine = (Ffd'F)/||Ffd||||F|| = %g\n", (double)fdnorm, (double)hcnorm, (double)(PetscRealPart(dot) / (fdnorm * hcnorm))));
2706: PetscCall(PetscViewerASCIIPrintf(viewer, " 2-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffnorm / PetscMax(hcnorm, fdnorm)), (double)diffnorm));
2707: PetscCall(PetscViewerASCIIPrintf(viewer, " max-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffmax / PetscMax(hcmax, fdmax)), (double)diffmax));
2709: if (complete_print) {
2710: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded function ----------\n"));
2711: PetscCall(VecView(g1, mviewer));
2712: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference function ----------\n"));
2713: PetscCall(VecView(g2, mviewer));
2714: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference function ----------\n"));
2715: PetscCall(VecView(g3, mviewer));
2716: }
2717: PetscCall(VecDestroy(&g1));
2718: PetscCall(VecDestroy(&g2));
2719: PetscCall(VecDestroy(&g3));
2721: if (complete_print) {
2722: PetscCall(PetscViewerPopFormat(mviewer));
2723: PetscCall(PetscViewerDestroy(&mviewer));
2724: }
2725: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2726: PetscFunctionReturn(PETSC_SUCCESS);
2727: }
2729: PetscErrorCode SNESTestJacobian(SNES snes)
2730: {
2731: Mat A, B, C, D, jacobian;
2732: Vec x = snes->vec_sol, f;
2733: PetscReal nrm, gnorm;
2734: PetscReal threshold = 1.e-5;
2735: MatType mattype;
2736: PetscInt m, n, M, N;
2737: void *functx;
2738: PetscBool complete_print = PETSC_FALSE, threshold_print = PETSC_FALSE, test = PETSC_FALSE, flg, istranspose;
2739: PetscViewer viewer, mviewer;
2740: MPI_Comm comm;
2741: PetscInt tabs;
2742: static PetscBool directionsprinted = PETSC_FALSE;
2743: PetscViewerFormat format;
2745: PetscFunctionBegin;
2746: PetscObjectOptionsBegin((PetscObject)snes);
2747: PetscCall(PetscOptionsName("-snes_test_jacobian", "Compare hand-coded and finite difference Jacobians", "None", &test));
2748: PetscCall(PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold, NULL));
2749: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display", "-snes_test_jacobian_view", "3.13", NULL));
2750: PetscCall(PetscOptionsViewer("-snes_test_jacobian_view", "View difference between hand-coded and finite difference Jacobians element entries", "None", &mviewer, &format, &complete_print));
2751: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display_threshold", "-snes_test_jacobian", "3.13", "-snes_test_jacobian accepts an optional threshold (since v3.10)"));
2752: 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));
2753: PetscOptionsEnd();
2754: if (!test) PetscFunctionReturn(PETSC_SUCCESS);
2756: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2757: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2758: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2759: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2760: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian -------------\n"));
2761: if (!complete_print && !directionsprinted) {
2762: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n"));
2763: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference Jacobian entries greater than <threshold>.\n"));
2764: }
2765: if (!directionsprinted) {
2766: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n"));
2767: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Jacobian is probably correct.\n"));
2768: directionsprinted = PETSC_TRUE;
2769: }
2770: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2772: PetscCall(PetscObjectTypeCompare((PetscObject)snes->jacobian, MATMFFD, &flg));
2773: if (!flg) jacobian = snes->jacobian;
2774: else jacobian = snes->jacobian_pre;
2776: if (!x) PetscCall(MatCreateVecs(jacobian, &x, NULL));
2777: else PetscCall(PetscObjectReference((PetscObject)x));
2778: PetscCall(VecDuplicate(x, &f));
2780: /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2781: PetscCall(SNESComputeFunction(snes, x, f));
2782: PetscCall(VecDestroy(&f));
2783: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESKSPTRANSPOSEONLY, &istranspose));
2784: while (jacobian) {
2785: Mat JT = NULL, Jsave = NULL;
2787: if (istranspose) {
2788: PetscCall(MatCreateTranspose(jacobian, &JT));
2789: Jsave = jacobian;
2790: jacobian = JT;
2791: }
2792: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)jacobian, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
2793: if (flg) {
2794: A = jacobian;
2795: PetscCall(PetscObjectReference((PetscObject)A));
2796: } else {
2797: PetscCall(MatComputeOperator(jacobian, MATAIJ, &A));
2798: }
2800: PetscCall(MatGetType(A, &mattype));
2801: PetscCall(MatGetSize(A, &M, &N));
2802: PetscCall(MatGetLocalSize(A, &m, &n));
2803: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &B));
2804: PetscCall(MatSetType(B, mattype));
2805: PetscCall(MatSetSizes(B, m, n, M, N));
2806: PetscCall(MatSetBlockSizesFromMats(B, A, A));
2807: PetscCall(MatSetUp(B));
2808: PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2810: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
2811: PetscCall(SNESComputeJacobianDefault(snes, x, B, B, functx));
2813: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &D));
2814: PetscCall(MatAYPX(D, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2815: PetscCall(MatNorm(D, NORM_FROBENIUS, &nrm));
2816: PetscCall(MatNorm(A, NORM_FROBENIUS, &gnorm));
2817: PetscCall(MatDestroy(&D));
2818: if (!gnorm) gnorm = 1; /* just in case */
2819: PetscCall(PetscViewerASCIIPrintf(viewer, " ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n", (double)(nrm / gnorm), (double)nrm));
2821: if (complete_print) {
2822: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded Jacobian ----------\n"));
2823: PetscCall(MatView(A, mviewer));
2824: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference Jacobian ----------\n"));
2825: PetscCall(MatView(B, mviewer));
2826: }
2828: if (threshold_print || complete_print) {
2829: PetscInt Istart, Iend, *ccols, bncols, cncols, j, row;
2830: PetscScalar *cvals;
2831: const PetscInt *bcols;
2832: const PetscScalar *bvals;
2834: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2835: PetscCall(MatSetType(C, mattype));
2836: PetscCall(MatSetSizes(C, m, n, M, N));
2837: PetscCall(MatSetBlockSizesFromMats(C, A, A));
2838: PetscCall(MatSetUp(C));
2839: PetscCall(MatSetOption(C, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2841: PetscCall(MatAYPX(B, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2842: PetscCall(MatGetOwnershipRange(B, &Istart, &Iend));
2844: for (row = Istart; row < Iend; row++) {
2845: PetscCall(MatGetRow(B, row, &bncols, &bcols, &bvals));
2846: PetscCall(PetscMalloc2(bncols, &ccols, bncols, &cvals));
2847: for (j = 0, cncols = 0; j < bncols; j++) {
2848: if (PetscAbsScalar(bvals[j]) > threshold) {
2849: ccols[cncols] = bcols[j];
2850: cvals[cncols] = bvals[j];
2851: cncols += 1;
2852: }
2853: }
2854: if (cncols) PetscCall(MatSetValues(C, 1, &row, cncols, ccols, cvals, INSERT_VALUES));
2855: PetscCall(MatRestoreRow(B, row, &bncols, &bcols, &bvals));
2856: PetscCall(PetscFree2(ccols, cvals));
2857: }
2858: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2859: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2860: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n", (double)threshold));
2861: PetscCall(MatView(C, complete_print ? mviewer : viewer));
2862: PetscCall(MatDestroy(&C));
2863: }
2864: PetscCall(MatDestroy(&A));
2865: PetscCall(MatDestroy(&B));
2866: PetscCall(MatDestroy(&JT));
2867: if (Jsave) jacobian = Jsave;
2868: if (jacobian != snes->jacobian_pre) {
2869: jacobian = snes->jacobian_pre;
2870: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian for preconditioner -------------\n"));
2871: } else jacobian = NULL;
2872: }
2873: PetscCall(VecDestroy(&x));
2874: if (complete_print) PetscCall(PetscViewerPopFormat(mviewer));
2875: if (mviewer) PetscCall(PetscViewerDestroy(&mviewer));
2876: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2877: PetscFunctionReturn(PETSC_SUCCESS);
2878: }
2880: /*@
2881: SNESComputeJacobian - Computes the Jacobian matrix that has been set with `SNESSetJacobian()`.
2883: Collective
2885: Input Parameters:
2886: + snes - the `SNES` context
2887: - X - input vector
2889: Output Parameters:
2890: + A - Jacobian matrix
2891: - B - optional matrix for building the preconditioner, usually the same as `A`
2893: Options Database Keys:
2894: + -snes_lag_preconditioner <lag> - how often to rebuild preconditioner
2895: . -snes_lag_jacobian <lag> - how often to rebuild Jacobian
2896: . -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.
2897: . -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
2898: . -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2899: . -snes_compare_explicit_draw - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2900: . -snes_compare_explicit_contour - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2901: . -snes_compare_operator - Make the comparison options above use the operator instead of the matrix used to construct the preconditioner
2902: . -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2903: . -snes_compare_coloring_display - Compute the finite difference Jacobian using coloring and display verbose differences
2904: . -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2905: . -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2906: . -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2907: . -snes_compare_coloring_draw - Compute the finite difference Jacobian using coloring and draw differences
2908: - -snes_compare_coloring_draw_contour - Compute the finite difference Jacobian using coloring and show contours of matrices and differences
2910: Level: developer
2912: Note:
2913: Most users should not need to explicitly call this routine, as it
2914: is used internally within the nonlinear solvers.
2916: Developer Note:
2917: 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
2918: with the `SNESType` of test that has been removed.
2920: .seealso: [](ch_snes), `SNESSetJacobian()`, `KSPSetOperators()`, `MatStructure`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
2921: @*/
2922: PetscErrorCode SNESComputeJacobian(SNES snes, Vec X, Mat A, Mat B)
2923: {
2924: PetscBool flag;
2925: DM dm;
2926: DMSNES sdm;
2927: KSP ksp;
2929: PetscFunctionBegin;
2932: PetscCheckSameComm(snes, 1, X, 2);
2933: PetscCall(VecValidValues_Internal(X, 2, PETSC_TRUE));
2934: PetscCall(SNESGetDM(snes, &dm));
2935: PetscCall(DMGetDMSNES(dm, &sdm));
2937: /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix-free */
2938: if (snes->lagjacobian == -2) {
2939: snes->lagjacobian = -1;
2941: PetscCall(PetscInfo(snes, "Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n"));
2942: } else if (snes->lagjacobian == -1) {
2943: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is -1\n"));
2944: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2945: if (flag) {
2946: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2947: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2948: }
2949: PetscFunctionReturn(PETSC_SUCCESS);
2950: } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2951: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagjacobian, snes->iter));
2952: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2953: if (flag) {
2954: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2955: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2956: }
2957: PetscFunctionReturn(PETSC_SUCCESS);
2958: }
2959: if (snes->npc && snes->npcside == PC_LEFT) {
2960: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2961: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2962: PetscFunctionReturn(PETSC_SUCCESS);
2963: }
2965: PetscCall(PetscLogEventBegin(SNES_JacobianEval, snes, X, A, B));
2966: PetscCall(VecLockReadPush(X));
2967: {
2968: void *ctx;
2969: SNESJacobianFn *J;
2970: PetscCall(DMSNESGetJacobian(dm, &J, &ctx));
2971: PetscCallBack("SNES callback Jacobian", (*J)(snes, X, A, B, ctx));
2972: }
2973: PetscCall(VecLockReadPop(X));
2974: PetscCall(PetscLogEventEnd(SNES_JacobianEval, snes, X, A, B));
2976: /* attach latest linearization point to the matrix used to construct the preconditioner */
2977: PetscCall(PetscObjectCompose((PetscObject)B, "__SNES_latest_X", (PetscObject)X));
2979: /* the next line ensures that snes->ksp exists */
2980: PetscCall(SNESGetKSP(snes, &ksp));
2981: if (snes->lagpreconditioner == -2) {
2982: PetscCall(PetscInfo(snes, "Rebuilding preconditioner exactly once since lag is -2\n"));
2983: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2984: snes->lagpreconditioner = -1;
2985: } else if (snes->lagpreconditioner == -1) {
2986: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is -1\n"));
2987: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2988: } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2989: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagpreconditioner, snes->iter));
2990: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2991: } else {
2992: PetscCall(PetscInfo(snes, "Rebuilding preconditioner\n"));
2993: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2994: }
2996: /* monkey business to allow testing Jacobians in multilevel solvers.
2997: This is needed because the SNESTestXXX interface does not accept vectors and matrices */
2998: {
2999: Vec xsave = snes->vec_sol;
3000: Mat jacobiansave = snes->jacobian;
3001: Mat jacobian_presave = snes->jacobian_pre;
3003: snes->vec_sol = X;
3004: snes->jacobian = A;
3005: snes->jacobian_pre = B;
3006: PetscCall(SNESTestFunction(snes));
3007: PetscCall(SNESTestJacobian(snes));
3009: snes->vec_sol = xsave;
3010: snes->jacobian = jacobiansave;
3011: snes->jacobian_pre = jacobian_presave;
3012: }
3014: {
3015: PetscBool flag = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_operator = PETSC_FALSE;
3016: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit", NULL, NULL, &flag));
3017: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw", NULL, NULL, &flag_draw));
3018: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw_contour", NULL, NULL, &flag_contour));
3019: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_operator", NULL, NULL, &flag_operator));
3020: if (flag || flag_draw || flag_contour) {
3021: Mat Bexp_mine = NULL, Bexp, FDexp;
3022: PetscViewer vdraw, vstdout;
3023: PetscBool flg;
3024: if (flag_operator) {
3025: PetscCall(MatComputeOperator(A, MATAIJ, &Bexp_mine));
3026: Bexp = Bexp_mine;
3027: } else {
3028: /* See if the matrix used to construct the preconditioner can be viewed and added directly */
3029: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)B, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPIBAIJ, ""));
3030: if (flg) Bexp = B;
3031: else {
3032: /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
3033: PetscCall(MatComputeOperator(B, MATAIJ, &Bexp_mine));
3034: Bexp = Bexp_mine;
3035: }
3036: }
3037: PetscCall(MatConvert(Bexp, MATSAME, MAT_INITIAL_MATRIX, &FDexp));
3038: PetscCall(SNESComputeJacobianDefault(snes, X, FDexp, FDexp, NULL));
3039: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3040: if (flag_draw || flag_contour) {
3041: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Explicit Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3042: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3043: } else vdraw = NULL;
3044: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit %s\n", flag_operator ? "Jacobian" : "preconditioning Jacobian"));
3045: if (flag) PetscCall(MatView(Bexp, vstdout));
3046: if (vdraw) PetscCall(MatView(Bexp, vdraw));
3047: PetscCall(PetscViewerASCIIPrintf(vstdout, "Finite difference Jacobian\n"));
3048: if (flag) PetscCall(MatView(FDexp, vstdout));
3049: if (vdraw) PetscCall(MatView(FDexp, vdraw));
3050: PetscCall(MatAYPX(FDexp, -1.0, Bexp, SAME_NONZERO_PATTERN));
3051: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian\n"));
3052: if (flag) PetscCall(MatView(FDexp, vstdout));
3053: if (vdraw) { /* Always use contour for the difference */
3054: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3055: PetscCall(MatView(FDexp, vdraw));
3056: PetscCall(PetscViewerPopFormat(vdraw));
3057: }
3058: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3059: PetscCall(PetscViewerDestroy(&vdraw));
3060: PetscCall(MatDestroy(&Bexp_mine));
3061: PetscCall(MatDestroy(&FDexp));
3062: }
3063: }
3064: {
3065: PetscBool flag = PETSC_FALSE, flag_display = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_threshold = PETSC_FALSE;
3066: PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON, threshold_rtol = 10 * PETSC_SQRT_MACHINE_EPSILON;
3067: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring", NULL, NULL, &flag));
3068: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_display", NULL, NULL, &flag_display));
3069: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw", NULL, NULL, &flag_draw));
3070: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw_contour", NULL, NULL, &flag_contour));
3071: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold", NULL, NULL, &flag_threshold));
3072: if (flag_threshold) {
3073: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_rtol", &threshold_rtol, NULL));
3074: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_atol", &threshold_atol, NULL));
3075: }
3076: if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
3077: Mat Bfd;
3078: PetscViewer vdraw, vstdout;
3079: MatColoring coloring;
3080: ISColoring iscoloring;
3081: MatFDColoring matfdcoloring;
3082: SNESFunctionFn *func;
3083: void *funcctx;
3084: PetscReal norm1, norm2, normmax;
3086: PetscCall(MatDuplicate(B, MAT_DO_NOT_COPY_VALUES, &Bfd));
3087: PetscCall(MatColoringCreate(Bfd, &coloring));
3088: PetscCall(MatColoringSetType(coloring, MATCOLORINGSL));
3089: PetscCall(MatColoringSetFromOptions(coloring));
3090: PetscCall(MatColoringApply(coloring, &iscoloring));
3091: PetscCall(MatColoringDestroy(&coloring));
3092: PetscCall(MatFDColoringCreate(Bfd, iscoloring, &matfdcoloring));
3093: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3094: PetscCall(MatFDColoringSetUp(Bfd, iscoloring, matfdcoloring));
3095: PetscCall(ISColoringDestroy(&iscoloring));
3097: /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
3098: PetscCall(SNESGetFunction(snes, NULL, &func, &funcctx));
3099: PetscCall(MatFDColoringSetFunction(matfdcoloring, (PetscErrorCode (*)(void))func, funcctx));
3100: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring, ((PetscObject)snes)->prefix));
3101: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring, "coloring_"));
3102: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3103: PetscCall(MatFDColoringApply(Bfd, matfdcoloring, X, snes));
3104: PetscCall(MatFDColoringDestroy(&matfdcoloring));
3106: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3107: if (flag_draw || flag_contour) {
3108: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Colored Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3109: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3110: } else vdraw = NULL;
3111: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit preconditioning Jacobian\n"));
3112: if (flag_display) PetscCall(MatView(B, vstdout));
3113: if (vdraw) PetscCall(MatView(B, vdraw));
3114: PetscCall(PetscViewerASCIIPrintf(vstdout, "Colored Finite difference Jacobian\n"));
3115: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3116: if (vdraw) PetscCall(MatView(Bfd, vdraw));
3117: PetscCall(MatAYPX(Bfd, -1.0, B, SAME_NONZERO_PATTERN));
3118: PetscCall(MatNorm(Bfd, NORM_1, &norm1));
3119: PetscCall(MatNorm(Bfd, NORM_FROBENIUS, &norm2));
3120: PetscCall(MatNorm(Bfd, NORM_MAX, &normmax));
3121: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n", (double)norm1, (double)norm2, (double)normmax));
3122: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3123: if (vdraw) { /* Always use contour for the difference */
3124: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3125: PetscCall(MatView(Bfd, vdraw));
3126: PetscCall(PetscViewerPopFormat(vdraw));
3127: }
3128: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3130: if (flag_threshold) {
3131: PetscInt bs, rstart, rend, i;
3132: PetscCall(MatGetBlockSize(B, &bs));
3133: PetscCall(MatGetOwnershipRange(B, &rstart, &rend));
3134: for (i = rstart; i < rend; i++) {
3135: const PetscScalar *ba, *ca;
3136: const PetscInt *bj, *cj;
3137: PetscInt bn, cn, j, maxentrycol = -1, maxdiffcol = -1, maxrdiffcol = -1;
3138: PetscReal maxentry = 0, maxdiff = 0, maxrdiff = 0;
3139: PetscCall(MatGetRow(B, i, &bn, &bj, &ba));
3140: PetscCall(MatGetRow(Bfd, i, &cn, &cj, &ca));
3141: PetscCheck(bn == cn, ((PetscObject)A)->comm, PETSC_ERR_PLIB, "Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
3142: for (j = 0; j < bn; j++) {
3143: PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3144: if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
3145: maxentrycol = bj[j];
3146: maxentry = PetscRealPart(ba[j]);
3147: }
3148: if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
3149: maxdiffcol = bj[j];
3150: maxdiff = PetscRealPart(ca[j]);
3151: }
3152: if (rdiff > maxrdiff) {
3153: maxrdiffcol = bj[j];
3154: maxrdiff = rdiff;
3155: }
3156: }
3157: if (maxrdiff > 1) {
3158: 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));
3159: for (j = 0; j < bn; j++) {
3160: PetscReal rdiff;
3161: rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3162: if (rdiff > 1) PetscCall(PetscViewerASCIIPrintf(vstdout, " (%" PetscInt_FMT ",%g:%g)", bj[j], (double)PetscRealPart(ba[j]), (double)PetscRealPart(ca[j])));
3163: }
3164: PetscCall(PetscViewerASCIIPrintf(vstdout, "\n"));
3165: }
3166: PetscCall(MatRestoreRow(B, i, &bn, &bj, &ba));
3167: PetscCall(MatRestoreRow(Bfd, i, &cn, &cj, &ca));
3168: }
3169: }
3170: PetscCall(PetscViewerDestroy(&vdraw));
3171: PetscCall(MatDestroy(&Bfd));
3172: }
3173: }
3174: PetscFunctionReturn(PETSC_SUCCESS);
3175: }
3177: /*@C
3178: SNESSetJacobian - Sets the function to compute Jacobian as well as the
3179: location to store the matrix.
3181: Logically Collective
3183: Input Parameters:
3184: + snes - the `SNES` context
3185: . Amat - the matrix that defines the (approximate) Jacobian
3186: . Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
3187: . J - Jacobian evaluation routine (if `NULL` then `SNES` retains any previously set value), see `SNESJacobianFn` for details
3188: - ctx - [optional] user-defined context for private data for the
3189: Jacobian evaluation routine (may be `NULL`) (if `NULL` then `SNES` retains any previously set value)
3191: Level: beginner
3193: Notes:
3194: If the `Amat` matrix and `Pmat` matrix are different you must call `MatAssemblyBegin()`/`MatAssemblyEnd()` on
3195: each matrix.
3197: If you know the operator `Amat` has a null space you can use `MatSetNullSpace()` and `MatSetTransposeNullSpace()` to supply the null
3198: space to `Amat` and the `KSP` solvers will automatically use that null space as needed during the solution process.
3200: If using `SNESComputeJacobianDefaultColor()` to assemble a Jacobian, the `ctx` argument
3201: must be a `MatFDColoring`.
3203: Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian. One common
3204: example is to use the "Picard linearization" which only differentiates through the highest order parts of each term using `SNESSetPicard()`
3206: .seealso: [](ch_snes), `SNES`, `KSPSetOperators()`, `SNESSetFunction()`, `MatMFFDComputeJacobian()`, `SNESComputeJacobianDefaultColor()`, `MatStructure`,
3207: `SNESSetPicard()`, `SNESJacobianFn`, `SNESFunctionFn`
3208: @*/
3209: PetscErrorCode SNESSetJacobian(SNES snes, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
3210: {
3211: DM dm;
3213: PetscFunctionBegin;
3217: if (Amat) PetscCheckSameComm(snes, 1, Amat, 2);
3218: if (Pmat) PetscCheckSameComm(snes, 1, Pmat, 3);
3219: PetscCall(SNESGetDM(snes, &dm));
3220: PetscCall(DMSNESSetJacobian(dm, J, ctx));
3221: if (Amat) {
3222: PetscCall(PetscObjectReference((PetscObject)Amat));
3223: PetscCall(MatDestroy(&snes->jacobian));
3225: snes->jacobian = Amat;
3226: }
3227: if (Pmat) {
3228: PetscCall(PetscObjectReference((PetscObject)Pmat));
3229: PetscCall(MatDestroy(&snes->jacobian_pre));
3231: snes->jacobian_pre = Pmat;
3232: }
3233: PetscFunctionReturn(PETSC_SUCCESS);
3234: }
3236: /*@C
3237: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
3238: provided context for evaluating the Jacobian.
3240: Not Collective, but `Mat` object will be parallel if `SNES` is
3242: Input Parameter:
3243: . snes - the nonlinear solver context
3245: Output Parameters:
3246: + Amat - location to stash (approximate) Jacobian matrix (or `NULL`)
3247: . Pmat - location to stash matrix used to compute the preconditioner (or `NULL`)
3248: . J - location to put Jacobian function (or `NULL`), for calling sequence see `SNESJacobianFn`
3249: - ctx - location to stash Jacobian ctx (or `NULL`)
3251: Level: advanced
3253: .seealso: [](ch_snes), `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFn`, `SNESGetFunction()`
3254: @*/
3255: PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
3256: {
3257: DM dm;
3259: PetscFunctionBegin;
3261: if (Amat) *Amat = snes->jacobian;
3262: if (Pmat) *Pmat = snes->jacobian_pre;
3263: PetscCall(SNESGetDM(snes, &dm));
3264: PetscCall(DMSNESGetJacobian(dm, J, ctx));
3265: PetscFunctionReturn(PETSC_SUCCESS);
3266: }
3268: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3269: {
3270: DM dm;
3271: DMSNES sdm;
3273: PetscFunctionBegin;
3274: PetscCall(SNESGetDM(snes, &dm));
3275: PetscCall(DMGetDMSNES(dm, &sdm));
3276: if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3277: DM dm;
3278: PetscBool isdense, ismf;
3280: PetscCall(SNESGetDM(snes, &dm));
3281: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &isdense, MATSEQDENSE, MATMPIDENSE, MATDENSE, NULL));
3282: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &ismf, MATMFFD, MATSHELL, NULL));
3283: if (isdense) {
3284: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefault, NULL));
3285: } else if (!ismf) {
3286: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefaultColor, NULL));
3287: }
3288: }
3289: PetscFunctionReturn(PETSC_SUCCESS);
3290: }
3292: /*@
3293: SNESSetUp - Sets up the internal data structures for the later use
3294: of a nonlinear solver `SNESSolve()`.
3296: Collective
3298: Input Parameter:
3299: . snes - the `SNES` context
3301: Level: advanced
3303: Note:
3304: For basic use of the `SNES` solvers the user does not need to explicitly call
3305: `SNESSetUp()`, since these actions will automatically occur during
3306: the call to `SNESSolve()`. However, if one wishes to control this
3307: phase separately, `SNESSetUp()` should be called after `SNESCreate()`
3308: and optional routines of the form SNESSetXXX(), but before `SNESSolve()`.
3310: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`, `SNESDestroy()`, `SNESSetFromOptions()`
3311: @*/
3312: PetscErrorCode SNESSetUp(SNES snes)
3313: {
3314: DM dm;
3315: DMSNES sdm;
3316: SNESLineSearch linesearch, pclinesearch;
3317: void *lsprectx, *lspostctx;
3318: PetscBool mf_operator, mf;
3319: Vec f, fpc;
3320: void *funcctx;
3321: void *jacctx, *appctx;
3322: Mat j, jpre;
3323: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, void *);
3324: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *);
3325: SNESFunctionFn *func;
3326: SNESJacobianFn *jac;
3328: PetscFunctionBegin;
3330: if (snes->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
3331: PetscCall(PetscLogEventBegin(SNES_SetUp, snes, 0, 0, 0));
3333: if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, SNESNEWTONLS));
3335: PetscCall(SNESGetFunction(snes, &snes->vec_func, NULL, NULL));
3337: PetscCall(SNESGetDM(snes, &dm));
3338: PetscCall(DMGetDMSNES(dm, &sdm));
3339: PetscCall(SNESSetDefaultComputeJacobian(snes));
3341: if (!snes->vec_func) PetscCall(DMCreateGlobalVector(dm, &snes->vec_func));
3343: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
3345: if (snes->linesearch) {
3346: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
3347: PetscCall(SNESLineSearchSetFunction(snes->linesearch, SNESComputeFunction));
3348: }
3350: PetscCall(SNESGetUseMatrixFree(snes, &mf_operator, &mf));
3351: if (snes->npc && snes->npcside == PC_LEFT) {
3352: snes->mf = PETSC_TRUE;
3353: snes->mf_operator = PETSC_FALSE;
3354: }
3356: if (snes->npc) {
3357: /* copy the DM over */
3358: PetscCall(SNESGetDM(snes, &dm));
3359: PetscCall(SNESSetDM(snes->npc, dm));
3361: PetscCall(SNESGetFunction(snes, &f, &func, &funcctx));
3362: PetscCall(VecDuplicate(f, &fpc));
3363: PetscCall(SNESSetFunction(snes->npc, fpc, func, funcctx));
3364: PetscCall(SNESGetJacobian(snes, &j, &jpre, &jac, &jacctx));
3365: PetscCall(SNESSetJacobian(snes->npc, j, jpre, jac, jacctx));
3366: PetscCall(SNESGetApplicationContext(snes, &appctx));
3367: PetscCall(SNESSetApplicationContext(snes->npc, appctx));
3368: PetscCall(SNESSetUseMatrixFree(snes->npc, mf_operator, mf));
3369: PetscCall(VecDestroy(&fpc));
3371: /* copy the function pointers over */
3372: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)snes->npc));
3374: /* default to 1 iteration */
3375: PetscCall(SNESSetTolerances(snes->npc, 0.0, 0.0, 0.0, 1, snes->npc->max_funcs));
3376: if (snes->npcside == PC_RIGHT) {
3377: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_FINAL_ONLY));
3378: } else {
3379: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_NONE));
3380: }
3381: PetscCall(SNESSetFromOptions(snes->npc));
3383: /* copy the line search context over */
3384: if (snes->linesearch && snes->npc->linesearch) {
3385: PetscCall(SNESGetLineSearch(snes, &linesearch));
3386: PetscCall(SNESGetLineSearch(snes->npc, &pclinesearch));
3387: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
3388: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
3389: PetscCall(SNESLineSearchSetPreCheck(pclinesearch, precheck, lsprectx));
3390: PetscCall(SNESLineSearchSetPostCheck(pclinesearch, postcheck, lspostctx));
3391: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch));
3392: }
3393: }
3394: if (snes->mf) PetscCall(SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version));
3395: if (snes->ops->usercompute && !snes->ctx) PetscCallBack("SNES callback compute application context", (*snes->ops->usercompute)(snes, &snes->ctx));
3397: snes->jac_iter = 0;
3398: snes->pre_iter = 0;
3400: PetscTryTypeMethod(snes, setup);
3402: PetscCall(SNESSetDefaultComputeJacobian(snes));
3404: if (snes->npc && snes->npcside == PC_LEFT) {
3405: if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3406: if (snes->linesearch) {
3407: PetscCall(SNESGetLineSearch(snes, &linesearch));
3408: PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunctionDefaultNPC));
3409: }
3410: }
3411: }
3412: PetscCall(PetscLogEventEnd(SNES_SetUp, snes, 0, 0, 0));
3413: snes->setupcalled = PETSC_TRUE;
3414: PetscFunctionReturn(PETSC_SUCCESS);
3415: }
3417: /*@
3418: 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
3420: Collective
3422: Input Parameter:
3423: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3425: Level: intermediate
3427: Notes:
3428: Any options set on the `SNES` object, including those set with `SNESSetFromOptions()` remain.
3430: Call this if you wish to reuse a `SNES` but with different size vectors
3432: Also calls the application context destroy routine set with `SNESSetComputeApplicationContext()`
3434: .seealso: [](ch_snes), `SNES`, `SNESDestroy()`, `SNESCreate()`, `SNESSetUp()`, `SNESSolve()`
3435: @*/
3436: PetscErrorCode SNESReset(SNES snes)
3437: {
3438: PetscFunctionBegin;
3440: if (snes->ops->ctxdestroy && snes->ctx) {
3441: PetscCallBack("SNES callback destroy application context", (*snes->ops->ctxdestroy)(&snes->ctx));
3442: snes->ctx = NULL;
3443: }
3444: if (snes->npc) PetscCall(SNESReset(snes->npc));
3446: PetscTryTypeMethod(snes, reset);
3447: if (snes->ksp) PetscCall(KSPReset(snes->ksp));
3449: if (snes->linesearch) PetscCall(SNESLineSearchReset(snes->linesearch));
3451: PetscCall(VecDestroy(&snes->vec_rhs));
3452: PetscCall(VecDestroy(&snes->vec_sol));
3453: PetscCall(VecDestroy(&snes->vec_sol_update));
3454: PetscCall(VecDestroy(&snes->vec_func));
3455: PetscCall(MatDestroy(&snes->jacobian));
3456: PetscCall(MatDestroy(&snes->jacobian_pre));
3457: PetscCall(MatDestroy(&snes->picard));
3458: PetscCall(VecDestroyVecs(snes->nwork, &snes->work));
3459: PetscCall(VecDestroyVecs(snes->nvwork, &snes->vwork));
3461: snes->alwayscomputesfinalresidual = PETSC_FALSE;
3463: snes->nwork = snes->nvwork = 0;
3464: snes->setupcalled = PETSC_FALSE;
3465: PetscFunctionReturn(PETSC_SUCCESS);
3466: }
3468: /*@
3469: SNESConvergedReasonViewCancel - Clears all the reason view functions for a `SNES` object provided with `SNESConvergedReasonViewSet()` also
3470: removes the default viewer.
3472: Collective
3474: Input Parameter:
3475: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3477: Level: intermediate
3479: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESReset()`, `SNESConvergedReasonViewSet()`
3480: @*/
3481: PetscErrorCode SNESConvergedReasonViewCancel(SNES snes)
3482: {
3483: PetscInt i;
3485: PetscFunctionBegin;
3487: for (i = 0; i < snes->numberreasonviews; i++) {
3488: if (snes->reasonviewdestroy[i]) PetscCall((*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]));
3489: }
3490: snes->numberreasonviews = 0;
3491: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
3492: PetscFunctionReturn(PETSC_SUCCESS);
3493: }
3495: /*@
3496: SNESDestroy - Destroys the nonlinear solver context that was created
3497: with `SNESCreate()`.
3499: Collective
3501: Input Parameter:
3502: . snes - the `SNES` context
3504: Level: beginner
3506: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`
3507: @*/
3508: PetscErrorCode SNESDestroy(SNES *snes)
3509: {
3510: DM dm;
3512: PetscFunctionBegin;
3513: if (!*snes) PetscFunctionReturn(PETSC_SUCCESS);
3515: if (--((PetscObject)*snes)->refct > 0) {
3516: *snes = NULL;
3517: PetscFunctionReturn(PETSC_SUCCESS);
3518: }
3520: PetscCall(SNESReset(*snes));
3521: PetscCall(SNESDestroy(&(*snes)->npc));
3523: /* if memory was published with SAWs then destroy it */
3524: PetscCall(PetscObjectSAWsViewOff((PetscObject)*snes));
3525: PetscTryTypeMethod(*snes, destroy);
3527: dm = (*snes)->dm;
3528: while (dm) {
3529: PetscCall(DMCoarsenHookRemove(dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, *snes));
3530: PetscCall(DMGetCoarseDM(dm, &dm));
3531: }
3533: PetscCall(DMDestroy(&(*snes)->dm));
3534: PetscCall(KSPDestroy(&(*snes)->ksp));
3535: PetscCall(SNESLineSearchDestroy(&(*snes)->linesearch));
3537: PetscCall(PetscFree((*snes)->kspconvctx));
3538: if ((*snes)->ops->convergeddestroy) PetscCall((*(*snes)->ops->convergeddestroy)((*snes)->cnvP));
3539: if ((*snes)->conv_hist_alloc) PetscCall(PetscFree2((*snes)->conv_hist, (*snes)->conv_hist_its));
3540: PetscCall(SNESMonitorCancel(*snes));
3541: PetscCall(SNESConvergedReasonViewCancel(*snes));
3542: PetscCall(PetscHeaderDestroy(snes));
3543: PetscFunctionReturn(PETSC_SUCCESS);
3544: }
3546: /* ----------- Routines to set solver parameters ---------- */
3548: /*@
3549: SNESSetLagPreconditioner - Sets when the preconditioner is rebuilt in the nonlinear solve `SNESSolve()`.
3551: Logically Collective
3553: Input Parameters:
3554: + snes - the `SNES` context
3555: - lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3556: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3558: Options Database Keys:
3559: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3560: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3561: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3562: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3564: Level: intermediate
3566: Notes:
3567: The default is 1
3569: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagPreconditionerPersists()` was called
3571: `SNESSetLagPreconditionerPersists()` allows using the same uniform lagging (for example every second linear solve) across multiple nonlinear solves.
3573: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetLagPreconditionerPersists()`,
3574: `SNESSetLagJacobianPersists()`, `SNES`, `SNESSolve()`
3575: @*/
3576: PetscErrorCode SNESSetLagPreconditioner(SNES snes, PetscInt lag)
3577: {
3578: PetscFunctionBegin;
3580: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3581: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3583: snes->lagpreconditioner = lag;
3584: PetscFunctionReturn(PETSC_SUCCESS);
3585: }
3587: /*@
3588: SNESSetGridSequence - sets the number of steps of grid sequencing that `SNES` will do
3590: Logically Collective
3592: Input Parameters:
3593: + snes - the `SNES` context
3594: - steps - the number of refinements to do, defaults to 0
3596: Options Database Key:
3597: . -snes_grid_sequence <steps> - Use grid sequencing to generate initial guess
3599: Level: intermediate
3601: Notes:
3602: Once grid sequencing is turned on `SNESSolve()` will automatically perform the solve on each grid refinement.
3604: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3606: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetGridSequence()`,
3607: `SNESSetDM()`, `SNESSolve()`
3608: @*/
3609: PetscErrorCode SNESSetGridSequence(SNES snes, PetscInt steps)
3610: {
3611: PetscFunctionBegin;
3614: snes->gridsequence = steps;
3615: PetscFunctionReturn(PETSC_SUCCESS);
3616: }
3618: /*@
3619: SNESGetGridSequence - gets the number of steps of grid sequencing that `SNES` will do
3621: Logically Collective
3623: Input Parameter:
3624: . snes - the `SNES` context
3626: Output Parameter:
3627: . steps - the number of refinements to do, defaults to 0
3629: Level: intermediate
3631: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetGridSequence()`
3632: @*/
3633: PetscErrorCode SNESGetGridSequence(SNES snes, PetscInt *steps)
3634: {
3635: PetscFunctionBegin;
3637: *steps = snes->gridsequence;
3638: PetscFunctionReturn(PETSC_SUCCESS);
3639: }
3641: /*@
3642: SNESGetLagPreconditioner - Return how often the preconditioner is rebuilt
3644: Not Collective
3646: Input Parameter:
3647: . snes - the `SNES` context
3649: Output Parameter:
3650: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3651: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3653: Level: intermediate
3655: Notes:
3656: The default is 1
3658: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3660: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3661: @*/
3662: PetscErrorCode SNESGetLagPreconditioner(SNES snes, PetscInt *lag)
3663: {
3664: PetscFunctionBegin;
3666: *lag = snes->lagpreconditioner;
3667: PetscFunctionReturn(PETSC_SUCCESS);
3668: }
3670: /*@
3671: SNESSetLagJacobian - Set when the Jacobian is rebuilt in the nonlinear solve. See `SNESSetLagPreconditioner()` for determining how
3672: often the preconditioner is rebuilt.
3674: Logically Collective
3676: Input Parameters:
3677: + snes - the `SNES` context
3678: - lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3679: the Jacobian is built etc. -2 means rebuild at next chance but then never again
3681: Options Database Keys:
3682: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3683: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3684: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3685: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag.
3687: Level: intermediate
3689: Notes:
3690: The default is 1
3692: The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3694: 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
3695: at the next Newton step but never again (unless it is reset to another value)
3697: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagPreconditioner()`, `SNESGetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3698: @*/
3699: PetscErrorCode SNESSetLagJacobian(SNES snes, PetscInt lag)
3700: {
3701: PetscFunctionBegin;
3703: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3704: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3706: snes->lagjacobian = lag;
3707: PetscFunctionReturn(PETSC_SUCCESS);
3708: }
3710: /*@
3711: SNESGetLagJacobian - Get how often the Jacobian is rebuilt. See `SNESGetLagPreconditioner()` to determine when the preconditioner is rebuilt
3713: Not Collective
3715: Input Parameter:
3716: . snes - the `SNES` context
3718: Output Parameter:
3719: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3720: the Jacobian is built etc.
3722: Level: intermediate
3724: Notes:
3725: The default is 1
3727: The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagJacobianPersists()` was called.
3729: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobian()`, `SNESSetLagPreconditioner()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3731: @*/
3732: PetscErrorCode SNESGetLagJacobian(SNES snes, PetscInt *lag)
3733: {
3734: PetscFunctionBegin;
3736: *lag = snes->lagjacobian;
3737: PetscFunctionReturn(PETSC_SUCCESS);
3738: }
3740: /*@
3741: SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple nonlinear solves
3743: Logically collective
3745: Input Parameters:
3746: + snes - the `SNES` context
3747: - flg - jacobian lagging persists if true
3749: Options Database Keys:
3750: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3751: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3752: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3753: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3755: Level: advanced
3757: Notes:
3758: Normally when `SNESSetLagJacobian()` is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3760: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3761: several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3762: timesteps may present huge efficiency gains.
3764: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditionerPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`
3765: @*/
3766: PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
3767: {
3768: PetscFunctionBegin;
3771: snes->lagjac_persist = flg;
3772: PetscFunctionReturn(PETSC_SUCCESS);
3773: }
3775: /*@
3776: SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves
3778: Logically Collective
3780: Input Parameters:
3781: + snes - the `SNES` context
3782: - flg - preconditioner lagging persists if true
3784: Options Database Keys:
3785: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3786: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3787: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3788: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3790: Level: developer
3792: Notes:
3793: Normally when `SNESSetLagPreconditioner()` is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3795: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3796: by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3797: several timesteps may present huge efficiency gains.
3799: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobianPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagPreconditioner()`
3800: @*/
3801: PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)
3802: {
3803: PetscFunctionBegin;
3806: snes->lagpre_persist = flg;
3807: PetscFunctionReturn(PETSC_SUCCESS);
3808: }
3810: /*@
3811: SNESSetForceIteration - force `SNESSolve()` to take at least one iteration regardless of the initial residual norm
3813: Logically Collective
3815: Input Parameters:
3816: + snes - the `SNES` context
3817: - force - `PETSC_TRUE` require at least one iteration
3819: Options Database Key:
3820: . -snes_force_iteration <force> - Sets forcing an iteration
3822: Level: intermediate
3824: Note:
3825: This is used sometimes with `TS` to prevent `TS` from detecting a false steady state solution
3827: .seealso: [](ch_snes), `SNES`, `TS`, `SNESSetDivergenceTolerance()`
3828: @*/
3829: PetscErrorCode SNESSetForceIteration(SNES snes, PetscBool force)
3830: {
3831: PetscFunctionBegin;
3833: snes->forceiteration = force;
3834: PetscFunctionReturn(PETSC_SUCCESS);
3835: }
3837: /*@
3838: SNESGetForceIteration - Check whether or not `SNESSolve()` take at least one iteration regardless of the initial residual norm
3840: Logically Collective
3842: Input Parameter:
3843: . snes - the `SNES` context
3845: Output Parameter:
3846: . force - `PETSC_TRUE` requires at least one iteration.
3848: Level: intermediate
3850: .seealso: [](ch_snes), `SNES`, `SNESSetForceIteration()`, `SNESSetDivergenceTolerance()`
3851: @*/
3852: PetscErrorCode SNESGetForceIteration(SNES snes, PetscBool *force)
3853: {
3854: PetscFunctionBegin;
3856: *force = snes->forceiteration;
3857: PetscFunctionReturn(PETSC_SUCCESS);
3858: }
3860: /*@
3861: SNESSetTolerances - Sets various parameters used in `SNES` convergence tests.
3863: Logically Collective
3865: Input Parameters:
3866: + snes - the `SNES` context
3867: . abstol - the absolute convergence tolerance, $ F(x^n) \le abstol $
3868: . rtol - the relative convergence tolerance, $ F(x^n) \le reltol * F(x^0) $
3869: . stol - convergence tolerance in terms of the norm of the change in the solution between steps, || delta x || < stol*|| x ||
3870: . maxit - the maximum number of iterations allowed in the solver, default 50.
3871: - maxf - the maximum number of function evaluations allowed in the solver (use `PETSC_UNLIMITED` indicates no limit), default 10,000
3873: Options Database Keys:
3874: + -snes_atol <abstol> - Sets `abstol`
3875: . -snes_rtol <rtol> - Sets `rtol`
3876: . -snes_stol <stol> - Sets `stol`
3877: . -snes_max_it <maxit> - Sets `maxit`
3878: - -snes_max_funcs <maxf> - Sets `maxf` (use `unlimited` to have no maximum)
3880: Level: intermediate
3882: Note:
3883: All parameters must be non-negative
3885: Use `PETSC_CURRENT` to retain the current value of any parameter and `PETSC_DETERMINE` to use the default value for the given `SNES`.
3886: The default value is the value in the object when its type is set.
3888: Use `PETSC_UNLIMITED` on `maxit` or `maxf` to indicate there is no bound on the number of iterations or number of function evaluations.
3890: Fortran Note:
3891: Use `PETSC_CURRENT_INTEGER`, `PETSC_CURRENT_REAL`, `PETSC_UNLIMITED_INTEGER`, `PETSC_DETERMINE_INTEGER`, or `PETSC_DETERMINE_REAL`
3893: .seealso: [](ch_snes), `SNESSolve()`, `SNES`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`
3894: @*/
3895: PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
3896: {
3897: PetscFunctionBegin;
3905: if (abstol == (PetscReal)PETSC_DETERMINE) {
3906: snes->abstol = snes->default_abstol;
3907: } else if (abstol != (PetscReal)PETSC_CURRENT) {
3908: PetscCheck(abstol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %g must be non-negative", (double)abstol);
3909: snes->abstol = abstol;
3910: }
3912: if (rtol == (PetscReal)PETSC_DETERMINE) {
3913: snes->rtol = snes->default_rtol;
3914: } else if (rtol != (PetscReal)PETSC_CURRENT) {
3915: 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);
3916: snes->rtol = rtol;
3917: }
3919: if (stol == (PetscReal)PETSC_DETERMINE) {
3920: snes->stol = snes->default_stol;
3921: } else if (stol != (PetscReal)PETSC_CURRENT) {
3922: PetscCheck(stol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Step tolerance %g must be non-negative", (double)stol);
3923: snes->stol = stol;
3924: }
3926: if (maxit == PETSC_DETERMINE) {
3927: snes->max_its = snes->default_max_its;
3928: } else if (maxit == PETSC_UNLIMITED) {
3929: snes->max_its = PETSC_INT_MAX;
3930: } else if (maxit != PETSC_CURRENT) {
3931: PetscCheck(maxit >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", maxit);
3932: snes->max_its = maxit;
3933: }
3935: if (maxf == PETSC_DETERMINE) {
3936: snes->max_funcs = snes->default_max_funcs;
3937: } else if (maxf == PETSC_UNLIMITED || maxf == -1) {
3938: snes->max_funcs = PETSC_UNLIMITED;
3939: } else if (maxf != PETSC_CURRENT) {
3940: PetscCheck(maxf >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of function evaluations %" PetscInt_FMT " must be nonnegative", maxf);
3941: snes->max_funcs = maxf;
3942: }
3943: PetscFunctionReturn(PETSC_SUCCESS);
3944: }
3946: /*@
3947: SNESSetDivergenceTolerance - Sets the divergence tolerance used for the `SNES` divergence test.
3949: Logically Collective
3951: Input Parameters:
3952: + snes - the `SNES` context
3953: - 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
3954: is stopped due to divergence.
3956: Options Database Key:
3957: . -snes_divergence_tolerance <divtol> - Sets `divtol`
3959: Level: intermediate
3961: Notes:
3962: Use `PETSC_DETERMINE` to use the default value from when the object's type was set.
3964: Fortran Note:
3965: Use ``PETSC_DETERMINE_REAL` or `PETSC_UNLIMITED_REAL`
3967: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetTolerances()`, `SNESGetDivergenceTolerance()`
3968: @*/
3969: PetscErrorCode SNESSetDivergenceTolerance(SNES snes, PetscReal divtol)
3970: {
3971: PetscFunctionBegin;
3975: if (divtol == (PetscReal)PETSC_DETERMINE) {
3976: snes->divtol = snes->default_divtol;
3977: } else if (divtol == (PetscReal)PETSC_UNLIMITED || divtol == -1) {
3978: snes->divtol = PETSC_UNLIMITED;
3979: } else if (divtol != (PetscReal)PETSC_CURRENT) {
3980: PetscCheck(divtol >= 1.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Divergence tolerance %g must be greater than 1.0", (double)divtol);
3981: snes->divtol = divtol;
3982: }
3983: PetscFunctionReturn(PETSC_SUCCESS);
3984: }
3986: /*@
3987: SNESGetTolerances - Gets various parameters used in `SNES` convergence tests.
3989: Not Collective
3991: Input Parameter:
3992: . snes - the `SNES` context
3994: Output Parameters:
3995: + atol - the absolute convergence tolerance
3996: . rtol - the relative convergence tolerance
3997: . stol - convergence tolerance in terms of the norm of the change in the solution between steps
3998: . maxit - the maximum number of iterations allowed
3999: - maxf - the maximum number of function evaluations allowed, `PETSC_UNLIMITED` indicates no bound
4001: Level: intermediate
4003: Notes:
4004: See `SNESSetTolerances()` for details on the parameters.
4006: The user can specify `NULL` for any parameter that is not needed.
4008: .seealso: [](ch_snes), `SNES`, `SNESSetTolerances()`
4009: @*/
4010: PetscErrorCode SNESGetTolerances(SNES snes, PetscReal *atol, PetscReal *rtol, PetscReal *stol, PetscInt *maxit, PetscInt *maxf)
4011: {
4012: PetscFunctionBegin;
4014: if (atol) *atol = snes->abstol;
4015: if (rtol) *rtol = snes->rtol;
4016: if (stol) *stol = snes->stol;
4017: if (maxit) *maxit = snes->max_its;
4018: if (maxf) *maxf = snes->max_funcs;
4019: PetscFunctionReturn(PETSC_SUCCESS);
4020: }
4022: /*@
4023: SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.
4025: Not Collective
4027: Input Parameters:
4028: + snes - the `SNES` context
4029: - divtol - divergence tolerance
4031: Level: intermediate
4033: .seealso: [](ch_snes), `SNES`, `SNESSetDivergenceTolerance()`
4034: @*/
4035: PetscErrorCode SNESGetDivergenceTolerance(SNES snes, PetscReal *divtol)
4036: {
4037: PetscFunctionBegin;
4039: if (divtol) *divtol = snes->divtol;
4040: PetscFunctionReturn(PETSC_SUCCESS);
4041: }
4043: PETSC_INTERN PetscErrorCode SNESMonitorRange_Private(SNES, PetscInt, PetscReal *);
4045: PetscErrorCode SNESMonitorLGRange(SNES snes, PetscInt n, PetscReal rnorm, void *monctx)
4046: {
4047: PetscDrawLG lg;
4048: PetscReal x, y, per;
4049: PetscViewer v = (PetscViewer)monctx;
4050: static PetscReal prev; /* should be in the context */
4051: PetscDraw draw;
4053: PetscFunctionBegin;
4055: PetscCall(PetscViewerDrawGetDrawLG(v, 0, &lg));
4056: if (!n) PetscCall(PetscDrawLGReset(lg));
4057: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4058: PetscCall(PetscDrawSetTitle(draw, "Residual norm"));
4059: x = (PetscReal)n;
4060: if (rnorm > 0.0) y = PetscLog10Real(rnorm);
4061: else y = -15.0;
4062: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4063: if (n < 20 || !(n % 5) || snes->reason) {
4064: PetscCall(PetscDrawLGDraw(lg));
4065: PetscCall(PetscDrawLGSave(lg));
4066: }
4068: PetscCall(PetscViewerDrawGetDrawLG(v, 1, &lg));
4069: if (!n) PetscCall(PetscDrawLGReset(lg));
4070: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4071: PetscCall(PetscDrawSetTitle(draw, "% elements > .2*max element"));
4072: PetscCall(SNESMonitorRange_Private(snes, n, &per));
4073: x = (PetscReal)n;
4074: y = 100.0 * per;
4075: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4076: if (n < 20 || !(n % 5) || snes->reason) {
4077: PetscCall(PetscDrawLGDraw(lg));
4078: PetscCall(PetscDrawLGSave(lg));
4079: }
4081: PetscCall(PetscViewerDrawGetDrawLG(v, 2, &lg));
4082: if (!n) {
4083: prev = rnorm;
4084: PetscCall(PetscDrawLGReset(lg));
4085: }
4086: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4087: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm"));
4088: x = (PetscReal)n;
4089: y = (prev - rnorm) / prev;
4090: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4091: if (n < 20 || !(n % 5) || snes->reason) {
4092: PetscCall(PetscDrawLGDraw(lg));
4093: PetscCall(PetscDrawLGSave(lg));
4094: }
4096: PetscCall(PetscViewerDrawGetDrawLG(v, 3, &lg));
4097: if (!n) PetscCall(PetscDrawLGReset(lg));
4098: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4099: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm*(% > .2 max)"));
4100: x = (PetscReal)n;
4101: y = (prev - rnorm) / (prev * per);
4102: if (n > 2) { /*skip initial crazy value */
4103: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4104: }
4105: if (n < 20 || !(n % 5) || snes->reason) {
4106: PetscCall(PetscDrawLGDraw(lg));
4107: PetscCall(PetscDrawLGSave(lg));
4108: }
4109: prev = rnorm;
4110: PetscFunctionReturn(PETSC_SUCCESS);
4111: }
4113: /*@
4114: SNESConverged - Run the convergence test and update the `SNESConvergedReason`.
4116: Collective
4118: Input Parameters:
4119: + snes - the `SNES` context
4120: . it - current iteration
4121: . xnorm - 2-norm of current iterate
4122: . snorm - 2-norm of current step
4123: - fnorm - 2-norm of function
4125: Level: developer
4127: Note:
4128: This routine is called by the `SNESSolve()` implementations.
4129: It does not typically need to be called by the user.
4131: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4132: @*/
4133: PetscErrorCode SNESConverged(SNES snes, PetscInt it, PetscReal xnorm, PetscReal snorm, PetscReal fnorm)
4134: {
4135: PetscFunctionBegin;
4136: if (!snes->reason) {
4137: if (snes->normschedule == SNES_NORM_ALWAYS) PetscUseTypeMethod(snes, converged, it, xnorm, snorm, fnorm, &snes->reason, snes->cnvP);
4138: if (it == snes->max_its && !snes->reason) {
4139: if (snes->normschedule == SNES_NORM_ALWAYS) {
4140: PetscCall(PetscInfo(snes, "Maximum number of iterations has been reached: %" PetscInt_FMT "\n", snes->max_its));
4141: snes->reason = SNES_DIVERGED_MAX_IT;
4142: } else snes->reason = SNES_CONVERGED_ITS;
4143: }
4144: }
4145: PetscFunctionReturn(PETSC_SUCCESS);
4146: }
4148: /*@
4149: SNESMonitor - runs any `SNES` monitor routines provided with `SNESMonitor()` or the options database
4151: Collective
4153: Input Parameters:
4154: + snes - nonlinear solver context obtained from `SNESCreate()`
4155: . iter - current iteration number
4156: - rnorm - current relative norm of the residual
4158: Level: developer
4160: Note:
4161: This routine is called by the `SNESSolve()` implementations.
4162: It does not typically need to be called by the user.
4164: .seealso: [](ch_snes), `SNES`, `SNESMonitorSet()`
4165: @*/
4166: PetscErrorCode SNESMonitor(SNES snes, PetscInt iter, PetscReal rnorm)
4167: {
4168: PetscInt i, n = snes->numbermonitors;
4170: PetscFunctionBegin;
4171: if (n > 0) SNESCheckFunctionNorm(snes, rnorm);
4172: PetscCall(VecLockReadPush(snes->vec_sol));
4173: for (i = 0; i < n; i++) PetscCall((*snes->monitor[i])(snes, iter, rnorm, snes->monitorcontext[i]));
4174: PetscCall(VecLockReadPop(snes->vec_sol));
4175: PetscFunctionReturn(PETSC_SUCCESS);
4176: }
4178: /* ------------ Routines to set performance monitoring options ----------- */
4180: /*MC
4181: SNESMonitorFunction - functional form passed to `SNESMonitorSet()` to monitor convergence of nonlinear solver
4183: Synopsis:
4184: #include <petscsnes.h>
4185: PetscErrorCode SNESMonitorFunction(SNES snes, PetscInt its, PetscReal norm, void *mctx)
4187: Collective
4189: Input Parameters:
4190: + snes - the `SNES` context
4191: . its - iteration number
4192: . norm - 2-norm function value (may be estimated)
4193: - mctx - [optional] monitoring context
4195: Level: advanced
4197: .seealso: [](ch_snes), `SNESMonitorSet()`, `SNESMonitorSet()`, `SNESMonitorGet()`
4198: M*/
4200: /*@C
4201: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
4202: iteration of the `SNES` nonlinear solver to display the iteration's
4203: progress.
4205: Logically Collective
4207: Input Parameters:
4208: + snes - the `SNES` context
4209: . f - the monitor function, for the calling sequence see `SNESMonitorFunction`
4210: . mctx - [optional] user-defined context for private data for the monitor routine (use `NULL` if no context is desired)
4211: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4213: Options Database Keys:
4214: + -snes_monitor - sets `SNESMonitorDefault()`
4215: . -snes_monitor draw::draw_lg - sets line graph monitor,
4216: - -snes_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `SNESMonitorSet()`, but does not cancel those set via
4217: the options database.
4219: Level: intermediate
4221: Note:
4222: Several different monitoring routines may be set by calling
4223: `SNESMonitorSet()` multiple times; all will be called in the
4224: order in which they were set.
4226: Fortran Note:
4227: Only a single monitor function can be set for each `SNES` object
4229: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESMonitorDefault()`, `SNESMonitorCancel()`, `SNESMonitorFunction`, `PetscCtxDestroyFn`
4230: @*/
4231: PetscErrorCode SNESMonitorSet(SNES snes, PetscErrorCode (*f)(SNES, PetscInt, PetscReal, void *), void *mctx, PetscCtxDestroyFn *monitordestroy)
4232: {
4233: PetscInt i;
4234: PetscBool identical;
4236: PetscFunctionBegin;
4238: for (i = 0; i < snes->numbermonitors; i++) {
4239: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))f, mctx, monitordestroy, (PetscErrorCode (*)(void))snes->monitor[i], snes->monitorcontext[i], snes->monitordestroy[i], &identical));
4240: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4241: }
4242: PetscCheck(snes->numbermonitors < MAXSNESMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
4243: snes->monitor[snes->numbermonitors] = f;
4244: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
4245: snes->monitorcontext[snes->numbermonitors++] = mctx;
4246: PetscFunctionReturn(PETSC_SUCCESS);
4247: }
4249: /*@
4250: SNESMonitorCancel - Clears all the monitor functions for a `SNES` object.
4252: Logically Collective
4254: Input Parameter:
4255: . snes - the `SNES` context
4257: Options Database Key:
4258: . -snes_monitor_cancel - cancels all monitors that have been hardwired
4259: into a code by calls to `SNESMonitorSet()`, but does not cancel those
4260: set via the options database
4262: Level: intermediate
4264: Note:
4265: There is no way to clear one specific monitor from a `SNES` object.
4267: .seealso: [](ch_snes), `SNES`, `SNESMonitorGet()`, `SNESMonitorDefault()`, `SNESMonitorSet()`
4268: @*/
4269: PetscErrorCode SNESMonitorCancel(SNES snes)
4270: {
4271: PetscInt i;
4273: PetscFunctionBegin;
4275: for (i = 0; i < snes->numbermonitors; i++) {
4276: if (snes->monitordestroy[i]) PetscCall((*snes->monitordestroy[i])(&snes->monitorcontext[i]));
4277: }
4278: snes->numbermonitors = 0;
4279: PetscFunctionReturn(PETSC_SUCCESS);
4280: }
4282: /*MC
4283: SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver
4285: Synopsis:
4286: #include <petscsnes.h>
4287: PetscErrorCode SNESConvergenceTest(SNES snes, PetscInt it, PetscReal xnorm, PetscReal gnorm, PetscReal f, SNESConvergedReason *reason, void *cctx)
4289: Collective
4291: Input Parameters:
4292: + snes - the `SNES` context
4293: . it - current iteration (0 is the first and is before any Newton step)
4294: . xnorm - 2-norm of current iterate
4295: . gnorm - 2-norm of current step
4296: . f - 2-norm of function
4297: - cctx - [optional] convergence context
4299: Output Parameter:
4300: . reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected
4302: Level: intermediate
4304: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4305: M*/
4307: /*@C
4308: SNESSetConvergenceTest - Sets the function that is to be used
4309: to test for convergence of the nonlinear iterative solution.
4311: Logically Collective
4313: Input Parameters:
4314: + snes - the `SNES` context
4315: . SNESConvergenceTestFunction - routine to test for convergence
4316: . cctx - [optional] context for private data for the convergence routine (may be `NULL`)
4317: - destroy - [optional] destructor for the context (may be `NULL`; `PETSC_NULL_FUNCTION` in Fortran)
4319: Level: advanced
4321: .seealso: [](ch_snes), `SNES`, `SNESConvergedDefault()`, `SNESConvergedSkip()`, `SNESConvergenceTestFunction`
4322: @*/
4323: PetscErrorCode SNESSetConvergenceTest(SNES snes, PetscErrorCode (*SNESConvergenceTestFunction)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *cctx, PetscErrorCode (*destroy)(void *))
4324: {
4325: PetscFunctionBegin;
4327: if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4328: if (snes->ops->convergeddestroy) PetscCall((*snes->ops->convergeddestroy)(snes->cnvP));
4329: snes->ops->converged = SNESConvergenceTestFunction;
4330: snes->ops->convergeddestroy = destroy;
4331: snes->cnvP = cctx;
4332: PetscFunctionReturn(PETSC_SUCCESS);
4333: }
4335: /*@
4336: SNESGetConvergedReason - Gets the reason the `SNES` iteration was stopped, which may be due to convergence, divergence, or stagnation
4338: Not Collective
4340: Input Parameter:
4341: . snes - the `SNES` context
4343: Output Parameter:
4344: . reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` for the individual convergence tests for complete lists
4346: Options Database Key:
4347: . -snes_converged_reason - prints the reason to standard out
4349: Level: intermediate
4351: Note:
4352: Should only be called after the call the `SNESSolve()` is complete, if it is called earlier it returns the value `SNES__CONVERGED_ITERATING`.
4354: .seealso: [](ch_snes), `SNESSolve()`, `SNESSetConvergenceTest()`, `SNESSetConvergedReason()`, `SNESConvergedReason`, `SNESGetConvergedReasonString()`
4355: @*/
4356: PetscErrorCode SNESGetConvergedReason(SNES snes, SNESConvergedReason *reason)
4357: {
4358: PetscFunctionBegin;
4360: PetscAssertPointer(reason, 2);
4361: *reason = snes->reason;
4362: PetscFunctionReturn(PETSC_SUCCESS);
4363: }
4365: /*@C
4366: SNESGetConvergedReasonString - Return a human readable string for `SNESConvergedReason`
4368: Not Collective
4370: Input Parameter:
4371: . snes - the `SNES` context
4373: Output Parameter:
4374: . strreason - a human readable string that describes `SNES` converged reason
4376: Level: beginner
4378: .seealso: [](ch_snes), `SNES`, `SNESGetConvergedReason()`
4379: @*/
4380: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char **strreason)
4381: {
4382: PetscFunctionBegin;
4384: PetscAssertPointer(strreason, 2);
4385: *strreason = SNESConvergedReasons[snes->reason];
4386: PetscFunctionReturn(PETSC_SUCCESS);
4387: }
4389: /*@
4390: SNESSetConvergedReason - Sets the reason the `SNES` iteration was stopped.
4392: Not Collective
4394: Input Parameters:
4395: + snes - the `SNES` context
4396: - reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` or the
4397: manual pages for the individual convergence tests for complete lists
4399: Level: developer
4401: Developer Note:
4402: Called inside the various `SNESSolve()` implementations
4404: .seealso: [](ch_snes), `SNESGetConvergedReason()`, `SNESSetConvergenceTest()`, `SNESConvergedReason`
4405: @*/
4406: PetscErrorCode SNESSetConvergedReason(SNES snes, SNESConvergedReason reason)
4407: {
4408: PetscFunctionBegin;
4410: PetscCheck(!snes->errorifnotconverged || reason > 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_PLIB, "SNES code should have previously errored due to negative reason");
4411: snes->reason = reason;
4412: PetscFunctionReturn(PETSC_SUCCESS);
4413: }
4415: /*@
4416: SNESSetConvergenceHistory - Sets the arrays used to hold the convergence history.
4418: Logically Collective
4420: Input Parameters:
4421: + snes - iterative context obtained from `SNESCreate()`
4422: . a - array to hold history, this array will contain the function norms computed at each step
4423: . its - integer array holds the number of linear iterations for each solve.
4424: . na - size of `a` and `its`
4425: - reset - `PETSC_TRUE` indicates each new nonlinear solve resets the history counter to zero,
4426: else it continues storing new values for new nonlinear solves after the old ones
4428: Level: intermediate
4430: Notes:
4431: If 'a' and 'its' are `NULL` then space is allocated for the history. If 'na' is `PETSC_DECIDE` (or, deprecated, `PETSC_DEFAULT`) then a
4432: default array of length 1,000 is allocated.
4434: This routine is useful, e.g., when running a code for purposes
4435: of accurate performance monitoring, when no I/O should be done
4436: during the section of code that is being timed.
4438: If the arrays run out of space after a number of iterations then the later values are not saved in the history
4440: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergenceHistory()`
4441: @*/
4442: PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)
4443: {
4444: PetscFunctionBegin;
4446: if (a) PetscAssertPointer(a, 2);
4447: if (its) PetscAssertPointer(its, 3);
4448: if (!a) {
4449: if (na == PETSC_DECIDE) na = 1000;
4450: PetscCall(PetscCalloc2(na, &a, na, &its));
4451: snes->conv_hist_alloc = PETSC_TRUE;
4452: }
4453: snes->conv_hist = a;
4454: snes->conv_hist_its = its;
4455: snes->conv_hist_max = (size_t)na;
4456: snes->conv_hist_len = 0;
4457: snes->conv_hist_reset = reset;
4458: PetscFunctionReturn(PETSC_SUCCESS);
4459: }
4461: #if defined(PETSC_HAVE_MATLAB)
4462: #include <engine.h> /* MATLAB include file */
4463: #include <mex.h> /* MATLAB include file */
4465: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4466: {
4467: mxArray *mat;
4468: PetscInt i;
4469: PetscReal *ar;
4471: mat = mxCreateDoubleMatrix(snes->conv_hist_len, 1, mxREAL);
4472: ar = (PetscReal *)mxGetData(mat);
4473: for (i = 0; i < snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4474: return mat;
4475: }
4476: #endif
4478: /*@C
4479: SNESGetConvergenceHistory - Gets the arrays used to hold the convergence history.
4481: Not Collective
4483: Input Parameter:
4484: . snes - iterative context obtained from `SNESCreate()`
4486: Output Parameters:
4487: + a - array to hold history, usually was set with `SNESSetConvergenceHistory()`
4488: . its - integer array holds the number of linear iterations (or
4489: negative if not converged) for each solve.
4490: - na - size of `a` and `its`
4492: Level: intermediate
4494: Note:
4495: This routine is useful, e.g., when running a code for purposes
4496: of accurate performance monitoring, when no I/O should be done
4497: during the section of code that is being timed.
4499: Fortran Notes:
4500: Return the arrays with ``SNESRestoreConvergenceHistory()`
4502: Use the arguments
4503: .vb
4504: PetscReal, pointer :: a(:)
4505: PetscInt, pointer :: its(:)
4506: .ve
4508: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetConvergenceHistory()`
4509: @*/
4510: PetscErrorCode SNESGetConvergenceHistory(SNES snes, PetscReal *a[], PetscInt *its[], PetscInt *na)
4511: {
4512: PetscFunctionBegin;
4514: if (a) *a = snes->conv_hist;
4515: if (its) *its = snes->conv_hist_its;
4516: if (na) *na = (PetscInt)snes->conv_hist_len;
4517: PetscFunctionReturn(PETSC_SUCCESS);
4518: }
4520: /*@C
4521: SNESSetUpdate - Sets the general-purpose update function called
4522: at the beginning of every iteration of the nonlinear solve. Specifically
4523: it is called just before the Jacobian is "evaluated" and after the function
4524: evaluation.
4526: Logically Collective
4528: Input Parameters:
4529: + snes - The nonlinear solver context
4530: - func - The update function; for calling sequence see `SNESUpdateFn`
4532: Level: advanced
4534: Notes:
4535: 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
4536: to `SNESSetFunction()`, or `SNESSetPicard()`
4537: This is not used by most users, and it is intended to provide a general hook that is run
4538: right before the direction step is computed.
4540: Users are free to modify the current residual vector,
4541: the current linearization point, or any other vector associated to the specific solver used.
4542: If such modifications take place, it is the user responsibility to update all the relevant
4543: vectors. For example, if one is adjusting the model parameters at each Newton step their code may look like
4544: .vb
4545: PetscErrorCode update(SNES snes, PetscInt iteration)
4546: {
4547: PetscFunctionBeginUser;
4548: if (iteration > 0) {
4549: // update the model parameters here
4550: Vec x,f;
4551: PetscCall(SNESGetSolution(snes,&x));
4552: PetcCall(SNESGetFunction(snes,&f,NULL,NULL));
4553: PetscCall(SNESComputeFunction(snes,x,f));
4554: }
4555: PetscFunctionReturn(PETSC_SUCCESS);
4556: }
4557: .ve
4559: 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.
4561: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetJacobian()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRSetPostCheck()`,
4562: `SNESMonitorSet()`
4563: @*/
4564: PetscErrorCode SNESSetUpdate(SNES snes, SNESUpdateFn *func)
4565: {
4566: PetscFunctionBegin;
4568: snes->ops->update = func;
4569: PetscFunctionReturn(PETSC_SUCCESS);
4570: }
4572: /*@
4573: SNESConvergedReasonView - Displays the reason a `SNES` solve converged or diverged to a viewer
4575: Collective
4577: Input Parameters:
4578: + snes - iterative context obtained from `SNESCreate()`
4579: - viewer - the viewer to display the reason
4581: Options Database Keys:
4582: + -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4583: - -snes_converged_reason ::failed - only print reason and number of iterations when diverged
4585: Level: beginner
4587: Note:
4588: To change the format of the output call `PetscViewerPushFormat`(viewer,format) before this call. Use `PETSC_VIEWER_DEFAULT` for the default,
4589: use `PETSC_VIEWER_FAILED` to only display a reason if it fails.
4591: .seealso: [](ch_snes), `SNESConvergedReason`, `PetscViewer`, `SNES`,
4592: `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`, `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`,
4593: `SNESConvergedReasonViewFromOptions()`,
4594: `PetscViewerPushFormat()`, `PetscViewerPopFormat()`
4595: @*/
4596: PetscErrorCode SNESConvergedReasonView(SNES snes, PetscViewer viewer)
4597: {
4598: PetscViewerFormat format;
4599: PetscBool isAscii;
4601: PetscFunctionBegin;
4602: if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4603: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isAscii));
4604: if (isAscii) {
4605: PetscCall(PetscViewerGetFormat(viewer, &format));
4606: PetscCall(PetscViewerASCIIAddTab(viewer, ((PetscObject)snes)->tablevel + 1));
4607: if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4608: DM dm;
4609: Vec u;
4610: PetscDS prob;
4611: PetscInt Nf, f;
4612: PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4613: void **exactCtx;
4614: PetscReal error;
4616: PetscCall(SNESGetDM(snes, &dm));
4617: PetscCall(SNESGetSolution(snes, &u));
4618: PetscCall(DMGetDS(dm, &prob));
4619: PetscCall(PetscDSGetNumFields(prob, &Nf));
4620: PetscCall(PetscMalloc2(Nf, &exactSol, Nf, &exactCtx));
4621: for (f = 0; f < Nf; ++f) PetscCall(PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]));
4622: PetscCall(DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error));
4623: PetscCall(PetscFree2(exactSol, exactCtx));
4624: if (error < 1.0e-11) PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n"));
4625: else PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", (double)error));
4626: }
4627: if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4628: if (((PetscObject)snes)->prefix) {
4629: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve converged due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4630: } else {
4631: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve converged due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4632: }
4633: } else if (snes->reason <= 0) {
4634: if (((PetscObject)snes)->prefix) {
4635: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve did not converge due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4636: } else {
4637: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve did not converge due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4638: }
4639: }
4640: PetscCall(PetscViewerASCIISubtractTab(viewer, ((PetscObject)snes)->tablevel + 1));
4641: }
4642: PetscFunctionReturn(PETSC_SUCCESS);
4643: }
4645: /*@C
4646: SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4647: end of the nonlinear solver to display the convergence reason of the nonlinear solver.
4649: Logically Collective
4651: Input Parameters:
4652: + snes - the `SNES` context
4653: . f - the `SNESConvergedReason` view function
4654: . vctx - [optional] user-defined context for private data for the `SNESConvergedReason` view function (use `NULL` if no context is desired)
4655: - reasonviewdestroy - [optional] routine that frees the context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4657: Calling sequence of `f`:
4658: + snes - the `SNES` context
4659: - vctx - [optional] context for private data for the function
4661: Options Database Keys:
4662: + -snes_converged_reason - sets a default `SNESConvergedReasonView()`
4663: - -snes_converged_reason_view_cancel - cancels all converged reason viewers that have been hardwired into a code by
4664: calls to `SNESConvergedReasonViewSet()`, but does not cancel those set via the options database.
4666: Level: intermediate
4668: Note:
4669: Several different converged reason view routines may be set by calling
4670: `SNESConvergedReasonViewSet()` multiple times; all will be called in the
4671: order in which they were set.
4673: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESConvergedReason`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`, `SNESConvergedReasonViewCancel()`,
4674: `PetscCtxDestroyFn`
4675: @*/
4676: PetscErrorCode SNESConvergedReasonViewSet(SNES snes, PetscErrorCode (*f)(SNES snes, void *vctx), void *vctx, PetscCtxDestroyFn *reasonviewdestroy)
4677: {
4678: PetscInt i;
4679: PetscBool identical;
4681: PetscFunctionBegin;
4683: for (i = 0; i < snes->numberreasonviews; i++) {
4684: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))f, vctx, reasonviewdestroy, (PetscErrorCode (*)(void))snes->reasonview[i], snes->reasonviewcontext[i], snes->reasonviewdestroy[i], &identical));
4685: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4686: }
4687: PetscCheck(snes->numberreasonviews < MAXSNESREASONVIEWS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many SNES reasonview set");
4688: snes->reasonview[snes->numberreasonviews] = f;
4689: snes->reasonviewdestroy[snes->numberreasonviews] = reasonviewdestroy;
4690: snes->reasonviewcontext[snes->numberreasonviews++] = vctx;
4691: PetscFunctionReturn(PETSC_SUCCESS);
4692: }
4694: /*@
4695: SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a `SNESConvergedReason` is to be viewed at the end of `SNESSolve()`
4696: All the user-provided viewer routines set with `SNESConvergedReasonViewSet()` will be called, if they exist.
4698: Collective
4700: Input Parameter:
4701: . snes - the `SNES` object
4703: Level: advanced
4705: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESConvergedReasonViewSet()`, `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`,
4706: `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`
4707: @*/
4708: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4709: {
4710: static PetscBool incall = PETSC_FALSE;
4712: PetscFunctionBegin;
4713: if (incall) PetscFunctionReturn(PETSC_SUCCESS);
4714: incall = PETSC_TRUE;
4716: /* All user-provided viewers are called first, if they exist. */
4717: for (PetscInt i = 0; i < snes->numberreasonviews; i++) PetscCall((*snes->reasonview[i])(snes, snes->reasonviewcontext[i]));
4719: /* Call PETSc default routine if users ask for it */
4720: if (snes->convergedreasonviewer) {
4721: PetscCall(PetscViewerPushFormat(snes->convergedreasonviewer, snes->convergedreasonformat));
4722: PetscCall(SNESConvergedReasonView(snes, snes->convergedreasonviewer));
4723: PetscCall(PetscViewerPopFormat(snes->convergedreasonviewer));
4724: }
4725: incall = PETSC_FALSE;
4726: PetscFunctionReturn(PETSC_SUCCESS);
4727: }
4729: /*@
4730: SNESSolve - Solves a nonlinear system $F(x) = b $ associated with a `SNES` object
4732: Collective
4734: Input Parameters:
4735: + snes - the `SNES` context
4736: . b - the constant part of the equation $F(x) = b$, or `NULL` to use zero.
4737: - x - the solution vector.
4739: Level: beginner
4741: Note:
4742: The user should initialize the vector, `x`, with the initial guess
4743: for the nonlinear solve prior to calling `SNESSolve()` .
4745: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFunction()`, `SNESSetJacobian()`, `SNESSetGridSequence()`, `SNESGetSolution()`,
4746: `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRGetPreCheck()`, `SNESNewtonTRSetPostCheck()`, `SNESNewtonTRGetPostCheck()`,
4747: `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`
4748: @*/
4749: PetscErrorCode SNESSolve(SNES snes, Vec b, Vec x)
4750: {
4751: PetscBool flg;
4752: PetscInt grid;
4753: Vec xcreated = NULL;
4754: DM dm;
4756: PetscFunctionBegin;
4759: if (x) PetscCheckSameComm(snes, 1, x, 3);
4761: if (b) PetscCheckSameComm(snes, 1, b, 2);
4763: /* High level operations using the nonlinear solver */
4764: {
4765: PetscViewer viewer;
4766: PetscViewerFormat format;
4767: PetscInt num;
4768: PetscBool flg;
4769: static PetscBool incall = PETSC_FALSE;
4771: if (!incall) {
4772: /* Estimate the convergence rate of the discretization */
4773: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg));
4774: if (flg) {
4775: PetscConvEst conv;
4776: DM dm;
4777: PetscReal *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4778: PetscInt Nf;
4780: incall = PETSC_TRUE;
4781: PetscCall(SNESGetDM(snes, &dm));
4782: PetscCall(DMGetNumFields(dm, &Nf));
4783: PetscCall(PetscCalloc1(Nf, &alpha));
4784: PetscCall(PetscConvEstCreate(PetscObjectComm((PetscObject)snes), &conv));
4785: PetscCall(PetscConvEstSetSolver(conv, (PetscObject)snes));
4786: PetscCall(PetscConvEstSetFromOptions(conv));
4787: PetscCall(PetscConvEstSetUp(conv));
4788: PetscCall(PetscConvEstGetConvRate(conv, alpha));
4789: PetscCall(PetscViewerPushFormat(viewer, format));
4790: PetscCall(PetscConvEstRateView(conv, alpha, viewer));
4791: PetscCall(PetscViewerPopFormat(viewer));
4792: PetscCall(PetscViewerDestroy(&viewer));
4793: PetscCall(PetscConvEstDestroy(&conv));
4794: PetscCall(PetscFree(alpha));
4795: incall = PETSC_FALSE;
4796: }
4797: /* Adaptively refine the initial grid */
4798: num = 1;
4799: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_initial", &num, &flg));
4800: if (flg) {
4801: DMAdaptor adaptor;
4803: incall = PETSC_TRUE;
4804: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4805: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4806: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4807: PetscCall(DMAdaptorSetFromOptions(adaptor));
4808: PetscCall(DMAdaptorSetUp(adaptor));
4809: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x));
4810: PetscCall(DMAdaptorDestroy(&adaptor));
4811: incall = PETSC_FALSE;
4812: }
4813: /* Use grid sequencing to adapt */
4814: num = 0;
4815: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_sequence", &num, NULL));
4816: if (num) {
4817: DMAdaptor adaptor;
4818: const char *prefix;
4820: incall = PETSC_TRUE;
4821: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4822: PetscCall(SNESGetOptionsPrefix(snes, &prefix));
4823: PetscCall(DMAdaptorSetOptionsPrefix(adaptor, prefix));
4824: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4825: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4826: PetscCall(DMAdaptorSetFromOptions(adaptor));
4827: PetscCall(DMAdaptorSetUp(adaptor));
4828: PetscCall(PetscObjectViewFromOptions((PetscObject)adaptor, NULL, "-snes_adapt_view"));
4829: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x));
4830: PetscCall(DMAdaptorDestroy(&adaptor));
4831: incall = PETSC_FALSE;
4832: }
4833: }
4834: }
4835: if (!x) x = snes->vec_sol;
4836: if (!x) {
4837: PetscCall(SNESGetDM(snes, &dm));
4838: PetscCall(DMCreateGlobalVector(dm, &xcreated));
4839: x = xcreated;
4840: }
4841: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view_pre"));
4843: for (grid = 0; grid < snes->gridsequence; grid++) PetscCall(PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4844: for (grid = 0; grid < snes->gridsequence + 1; grid++) {
4845: /* set solution vector */
4846: if (!grid) PetscCall(PetscObjectReference((PetscObject)x));
4847: PetscCall(VecDestroy(&snes->vec_sol));
4848: snes->vec_sol = x;
4849: PetscCall(SNESGetDM(snes, &dm));
4851: /* set affine vector if provided */
4852: if (b) PetscCall(PetscObjectReference((PetscObject)b));
4853: PetscCall(VecDestroy(&snes->vec_rhs));
4854: snes->vec_rhs = b;
4856: 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");
4857: PetscCheck(snes->vec_func != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be function vector");
4858: PetscCheck(snes->vec_rhs != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be right-hand side vector");
4859: if (!snes->vec_sol_update /* && snes->vec_sol */) PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_sol_update));
4860: PetscCall(DMShellSetGlobalVector(dm, snes->vec_sol));
4861: PetscCall(SNESSetUp(snes));
4863: if (!grid) {
4864: if (snes->ops->computeinitialguess) PetscCallBack("SNES callback compute initial guess", (*snes->ops->computeinitialguess)(snes, snes->vec_sol, snes->initialguessP));
4865: }
4867: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4868: PetscCall(SNESResetCounters(snes));
4869: snes->reason = SNES_CONVERGED_ITERATING;
4870: PetscCall(PetscLogEventBegin(SNES_Solve, snes, 0, 0, 0));
4871: PetscUseTypeMethod(snes, solve);
4872: PetscCall(PetscLogEventEnd(SNES_Solve, snes, 0, 0, 0));
4873: PetscCheck(snes->reason, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Internal error, solver %s returned without setting converged reason", ((PetscObject)snes)->type_name);
4874: snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */
4876: if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4877: if (snes->lagpre_persist) snes->pre_iter += snes->iter;
4879: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_test_local_min", NULL, NULL, &flg));
4880: if (flg && !PetscPreLoadingOn) PetscCall(SNESTestLocalMin(snes));
4881: /* Call converged reason views. This may involve user-provided viewers as well */
4882: PetscCall(SNESConvergedReasonViewFromOptions(snes));
4884: if (snes->errorifnotconverged) PetscCheck(snes->reason >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_NOT_CONVERGED, "SNESSolve has not converged");
4885: if (snes->reason < 0) break;
4886: if (grid < snes->gridsequence) {
4887: DM fine;
4888: Vec xnew;
4889: Mat interp;
4891: PetscCall(DMRefine(snes->dm, PetscObjectComm((PetscObject)snes), &fine));
4892: PetscCheck(fine, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "DMRefine() did not perform any refinement, cannot continue grid sequencing");
4893: PetscCall(DMGetCoordinatesLocalSetUp(fine));
4894: PetscCall(DMCreateInterpolation(snes->dm, fine, &interp, NULL));
4895: PetscCall(DMCreateGlobalVector(fine, &xnew));
4896: PetscCall(MatInterpolate(interp, x, xnew));
4897: PetscCall(DMInterpolate(snes->dm, interp, fine));
4898: PetscCall(MatDestroy(&interp));
4899: x = xnew;
4901: PetscCall(SNESReset(snes));
4902: PetscCall(SNESSetDM(snes, fine));
4903: PetscCall(SNESResetFromOptions(snes));
4904: PetscCall(DMDestroy(&fine));
4905: PetscCall(PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4906: }
4907: }
4908: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view"));
4909: PetscCall(VecViewFromOptions(snes->vec_sol, (PetscObject)snes, "-snes_view_solution"));
4910: PetscCall(DMMonitor(snes->dm));
4911: PetscCall(SNESMonitorPauseFinal_Internal(snes));
4913: PetscCall(VecDestroy(&xcreated));
4914: PetscCall(PetscObjectSAWsBlock((PetscObject)snes));
4915: PetscFunctionReturn(PETSC_SUCCESS);
4916: }
4918: /* --------- Internal routines for SNES Package --------- */
4920: /*@
4921: SNESSetType - Sets the algorithm/method to be used to solve the nonlinear system with the given `SNES`
4923: Collective
4925: Input Parameters:
4926: + snes - the `SNES` context
4927: - type - a known method
4929: Options Database Key:
4930: . -snes_type <type> - Sets the method; use -help for a list
4931: of available methods (for instance, newtonls or newtontr)
4933: Level: intermediate
4935: Notes:
4936: See `SNESType` for available methods (for instance)
4937: + `SNESNEWTONLS` - Newton's method with line search
4938: (systems of nonlinear equations)
4939: - `SNESNEWTONTR` - Newton's method with trust region
4940: (systems of nonlinear equations)
4942: Normally, it is best to use the `SNESSetFromOptions()` command and then
4943: set the `SNES` solver type from the options database rather than by using
4944: this routine. Using the options database provides the user with
4945: maximum flexibility in evaluating the many nonlinear solvers.
4946: The `SNESSetType()` routine is provided for those situations where it
4947: is necessary to set the nonlinear solver independently of the command
4948: line or options database. This might be the case, for example, when
4949: the choice of solver changes during the execution of the program,
4950: and the user's application is taking responsibility for choosing the
4951: appropriate method.
4953: Developer Note:
4954: `SNESRegister()` adds a constructor for a new `SNESType` to `SNESList`, `SNESSetType()` locates
4955: the constructor in that list and calls it to create the specific object.
4957: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESType`, `SNESCreate()`, `SNESDestroy()`, `SNESGetType()`, `SNESSetFromOptions()`
4958: @*/
4959: PetscErrorCode SNESSetType(SNES snes, SNESType type)
4960: {
4961: PetscBool match;
4962: PetscErrorCode (*r)(SNES);
4964: PetscFunctionBegin;
4966: PetscAssertPointer(type, 2);
4968: PetscCall(PetscObjectTypeCompare((PetscObject)snes, type, &match));
4969: if (match) PetscFunctionReturn(PETSC_SUCCESS);
4971: PetscCall(PetscFunctionListFind(SNESList, type, &r));
4972: PetscCheck(r, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested SNES type %s", type);
4973: /* Destroy the previous private SNES context */
4974: PetscTryTypeMethod(snes, destroy);
4975: /* Reinitialize type-specific function pointers in SNESOps structure */
4976: snes->ops->reset = NULL;
4977: snes->ops->setup = NULL;
4978: snes->ops->solve = NULL;
4979: snes->ops->view = NULL;
4980: snes->ops->setfromoptions = NULL;
4981: snes->ops->destroy = NULL;
4983: /* It may happen the user has customized the line search before calling SNESSetType */
4984: if (((PetscObject)snes)->type_name) PetscCall(SNESLineSearchDestroy(&snes->linesearch));
4986: /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4987: snes->setupcalled = PETSC_FALSE;
4989: PetscCall(PetscObjectChangeTypeName((PetscObject)snes, type));
4990: PetscCall((*r)(snes));
4991: PetscFunctionReturn(PETSC_SUCCESS);
4992: }
4994: /*@
4995: SNESGetType - Gets the `SNES` method type and name (as a string).
4997: Not Collective
4999: Input Parameter:
5000: . snes - nonlinear solver context
5002: Output Parameter:
5003: . type - `SNES` method (a character string)
5005: Level: intermediate
5007: .seealso: [](ch_snes), `SNESSetType()`, `SNESType`, `SNESSetFromOptions()`, `SNES`
5008: @*/
5009: PetscErrorCode SNESGetType(SNES snes, SNESType *type)
5010: {
5011: PetscFunctionBegin;
5013: PetscAssertPointer(type, 2);
5014: *type = ((PetscObject)snes)->type_name;
5015: PetscFunctionReturn(PETSC_SUCCESS);
5016: }
5018: /*@
5019: SNESSetSolution - Sets the solution vector for use by the `SNES` routines.
5021: Logically Collective
5023: Input Parameters:
5024: + snes - the `SNES` context obtained from `SNESCreate()`
5025: - u - the solution vector
5027: Level: beginner
5029: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetSolution()`, `Vec`
5030: @*/
5031: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
5032: {
5033: DM dm;
5035: PetscFunctionBegin;
5038: PetscCall(PetscObjectReference((PetscObject)u));
5039: PetscCall(VecDestroy(&snes->vec_sol));
5041: snes->vec_sol = u;
5043: PetscCall(SNESGetDM(snes, &dm));
5044: PetscCall(DMShellSetGlobalVector(dm, u));
5045: PetscFunctionReturn(PETSC_SUCCESS);
5046: }
5048: /*@
5049: SNESGetSolution - Returns the vector where the approximate solution is
5050: stored. This is the fine grid solution when using `SNESSetGridSequence()`.
5052: Not Collective, but `x` is parallel if `snes` is parallel
5054: Input Parameter:
5055: . snes - the `SNES` context
5057: Output Parameter:
5058: . x - the solution
5060: Level: intermediate
5062: .seealso: [](ch_snes), `SNESSetSolution()`, `SNESSolve()`, `SNES`, `SNESGetSolutionUpdate()`, `SNESGetFunction()`
5063: @*/
5064: PetscErrorCode SNESGetSolution(SNES snes, Vec *x)
5065: {
5066: PetscFunctionBegin;
5068: PetscAssertPointer(x, 2);
5069: *x = snes->vec_sol;
5070: PetscFunctionReturn(PETSC_SUCCESS);
5071: }
5073: /*@
5074: SNESGetSolutionUpdate - Returns the vector where the solution update is
5075: stored.
5077: Not Collective, but `x` is parallel if `snes` is parallel
5079: Input Parameter:
5080: . snes - the `SNES` context
5082: Output Parameter:
5083: . x - the solution update
5085: Level: advanced
5087: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`
5088: @*/
5089: PetscErrorCode SNESGetSolutionUpdate(SNES snes, Vec *x)
5090: {
5091: PetscFunctionBegin;
5093: PetscAssertPointer(x, 2);
5094: *x = snes->vec_sol_update;
5095: PetscFunctionReturn(PETSC_SUCCESS);
5096: }
5098: /*@C
5099: SNESGetFunction - Returns the function that defines the nonlinear system set with `SNESSetFunction()`
5101: Not Collective, but `r` is parallel if `snes` is parallel. Collective if `r` is requested, but has not been created yet.
5103: Input Parameter:
5104: . snes - the `SNES` context
5106: Output Parameters:
5107: + r - the vector that is used to store residuals (or `NULL` if you don't want it)
5108: . f - the function (or `NULL` if you don't want it); for calling sequence see `SNESFunctionFn`
5109: - ctx - the function context (or `NULL` if you don't want it)
5111: Level: advanced
5113: Note:
5114: The vector `r` DOES NOT, in general, contain the current value of the `SNES` nonlinear function
5116: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetSolution()`, `SNESFunctionFn`
5117: @*/
5118: PetscErrorCode SNESGetFunction(SNES snes, Vec *r, SNESFunctionFn **f, void **ctx)
5119: {
5120: DM dm;
5122: PetscFunctionBegin;
5124: if (r) {
5125: if (!snes->vec_func) {
5126: if (snes->vec_rhs) {
5127: PetscCall(VecDuplicate(snes->vec_rhs, &snes->vec_func));
5128: } else if (snes->vec_sol) {
5129: PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_func));
5130: } else if (snes->dm) {
5131: PetscCall(DMCreateGlobalVector(snes->dm, &snes->vec_func));
5132: }
5133: }
5134: *r = snes->vec_func;
5135: }
5136: PetscCall(SNESGetDM(snes, &dm));
5137: PetscCall(DMSNESGetFunction(dm, f, ctx));
5138: PetscFunctionReturn(PETSC_SUCCESS);
5139: }
5141: /*@C
5142: SNESGetNGS - Returns the function and context set with `SNESSetNGS()`
5144: Input Parameter:
5145: . snes - the `SNES` context
5147: Output Parameters:
5148: + f - the function (or `NULL`) see `SNESNGSFn` for calling sequence
5149: - ctx - the function context (or `NULL`)
5151: Level: advanced
5153: .seealso: [](ch_snes), `SNESSetNGS()`, `SNESGetFunction()`, `SNESNGSFn`
5154: @*/
5155: PetscErrorCode SNESGetNGS(SNES snes, SNESNGSFn **f, void **ctx)
5156: {
5157: DM dm;
5159: PetscFunctionBegin;
5161: PetscCall(SNESGetDM(snes, &dm));
5162: PetscCall(DMSNESGetNGS(dm, f, ctx));
5163: PetscFunctionReturn(PETSC_SUCCESS);
5164: }
5166: /*@
5167: SNESSetOptionsPrefix - Sets the prefix used for searching for all
5168: `SNES` options in the database.
5170: Logically Collective
5172: Input Parameters:
5173: + snes - the `SNES` context
5174: - prefix - the prefix to prepend to all option names
5176: Level: advanced
5178: Note:
5179: A hyphen (-) must NOT be given at the beginning of the prefix name.
5180: The first character of all runtime options is AUTOMATICALLY the hyphen.
5182: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESAppendOptionsPrefix()`
5183: @*/
5184: PetscErrorCode SNESSetOptionsPrefix(SNES snes, const char prefix[])
5185: {
5186: PetscFunctionBegin;
5188: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes, prefix));
5189: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5190: if (snes->linesearch) {
5191: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5192: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch, prefix));
5193: }
5194: PetscCall(KSPSetOptionsPrefix(snes->ksp, prefix));
5195: PetscFunctionReturn(PETSC_SUCCESS);
5196: }
5198: /*@
5199: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
5200: `SNES` options in the database.
5202: Logically Collective
5204: Input Parameters:
5205: + snes - the `SNES` context
5206: - prefix - the prefix to prepend to all option names
5208: Level: advanced
5210: Note:
5211: A hyphen (-) must NOT be given at the beginning of the prefix name.
5212: The first character of all runtime options is AUTOMATICALLY the hyphen.
5214: .seealso: [](ch_snes), `SNESGetOptionsPrefix()`, `SNESSetOptionsPrefix()`
5215: @*/
5216: PetscErrorCode SNESAppendOptionsPrefix(SNES snes, const char prefix[])
5217: {
5218: PetscFunctionBegin;
5220: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes, prefix));
5221: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5222: if (snes->linesearch) {
5223: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5224: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch, prefix));
5225: }
5226: PetscCall(KSPAppendOptionsPrefix(snes->ksp, prefix));
5227: PetscFunctionReturn(PETSC_SUCCESS);
5228: }
5230: /*@
5231: SNESGetOptionsPrefix - Gets the prefix used for searching for all
5232: `SNES` options in the database.
5234: Not Collective
5236: Input Parameter:
5237: . snes - the `SNES` context
5239: Output Parameter:
5240: . prefix - pointer to the prefix string used
5242: Level: advanced
5244: .seealso: [](ch_snes), `SNES`, `SNESSetOptionsPrefix()`, `SNESAppendOptionsPrefix()`
5245: @*/
5246: PetscErrorCode SNESGetOptionsPrefix(SNES snes, const char *prefix[])
5247: {
5248: PetscFunctionBegin;
5250: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, prefix));
5251: PetscFunctionReturn(PETSC_SUCCESS);
5252: }
5254: /*@C
5255: SNESRegister - Adds a method to the nonlinear solver package.
5257: Not Collective
5259: Input Parameters:
5260: + sname - name of a new user-defined solver
5261: - function - routine to create method context
5263: Level: advanced
5265: Note:
5266: `SNESRegister()` may be called multiple times to add several user-defined solvers.
5268: Example Usage:
5269: .vb
5270: SNESRegister("my_solver", MySolverCreate);
5271: .ve
5273: Then, your solver can be chosen with the procedural interface via
5274: .vb
5275: SNESSetType(snes, "my_solver")
5276: .ve
5277: or at runtime via the option
5278: .vb
5279: -snes_type my_solver
5280: .ve
5282: .seealso: [](ch_snes), `SNESRegisterAll()`, `SNESRegisterDestroy()`
5283: @*/
5284: PetscErrorCode SNESRegister(const char sname[], PetscErrorCode (*function)(SNES))
5285: {
5286: PetscFunctionBegin;
5287: PetscCall(SNESInitializePackage());
5288: PetscCall(PetscFunctionListAdd(&SNESList, sname, function));
5289: PetscFunctionReturn(PETSC_SUCCESS);
5290: }
5292: PetscErrorCode SNESTestLocalMin(SNES snes)
5293: {
5294: PetscInt N, i, j;
5295: Vec u, uh, fh;
5296: PetscScalar value;
5297: PetscReal norm;
5299: PetscFunctionBegin;
5300: PetscCall(SNESGetSolution(snes, &u));
5301: PetscCall(VecDuplicate(u, &uh));
5302: PetscCall(VecDuplicate(u, &fh));
5304: /* currently only works for sequential */
5305: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "Testing FormFunction() for local min\n"));
5306: PetscCall(VecGetSize(u, &N));
5307: for (i = 0; i < N; i++) {
5308: PetscCall(VecCopy(u, uh));
5309: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "i = %" PetscInt_FMT "\n", i));
5310: for (j = -10; j < 11; j++) {
5311: value = PetscSign(j) * PetscExpReal(PetscAbs(j) - 10.0);
5312: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5313: PetscCall(SNESComputeFunction(snes, uh, fh));
5314: PetscCall(VecNorm(fh, NORM_2, &norm));
5315: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), " j norm %" PetscInt_FMT " %18.16e\n", j, (double)norm));
5316: value = -value;
5317: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5318: }
5319: }
5320: PetscCall(VecDestroy(&uh));
5321: PetscCall(VecDestroy(&fh));
5322: PetscFunctionReturn(PETSC_SUCCESS);
5323: }
5325: /*@
5326: SNESKSPSetUseEW - Sets `SNES` to the use Eisenstat-Walker method for
5327: computing relative tolerance for linear solvers within an inexact
5328: Newton method.
5330: Logically Collective
5332: Input Parameters:
5333: + snes - `SNES` context
5334: - flag - `PETSC_TRUE` or `PETSC_FALSE`
5336: Options Database Keys:
5337: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5338: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
5339: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5340: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5341: . -snes_ksp_ew_gamma <gamma> - Sets gamma
5342: . -snes_ksp_ew_alpha <alpha> - Sets alpha
5343: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5344: - -snes_ksp_ew_threshold <threshold> - Sets threshold
5346: Level: advanced
5348: Note:
5349: The default is to use a constant relative tolerance for
5350: the inner linear solvers. Alternatively, one can use the
5351: Eisenstat-Walker method {cite}`ew96`, where the relative convergence tolerance
5352: is reset at each Newton iteration according progress of the nonlinear
5353: solver.
5355: .seealso: [](ch_snes), `KSP`, `SNES`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5356: @*/
5357: PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)
5358: {
5359: PetscFunctionBegin;
5362: snes->ksp_ewconv = flag;
5363: PetscFunctionReturn(PETSC_SUCCESS);
5364: }
5366: /*@
5367: SNESKSPGetUseEW - Gets if `SNES` is using Eisenstat-Walker method
5368: for computing relative tolerance for linear solvers within an
5369: inexact Newton method.
5371: Not Collective
5373: Input Parameter:
5374: . snes - `SNES` context
5376: Output Parameter:
5377: . flag - `PETSC_TRUE` or `PETSC_FALSE`
5379: Level: advanced
5381: .seealso: [](ch_snes), `SNESKSPSetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5382: @*/
5383: PetscErrorCode SNESKSPGetUseEW(SNES snes, PetscBool *flag)
5384: {
5385: PetscFunctionBegin;
5387: PetscAssertPointer(flag, 2);
5388: *flag = snes->ksp_ewconv;
5389: PetscFunctionReturn(PETSC_SUCCESS);
5390: }
5392: /*@
5393: SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5394: convergence criteria for the linear solvers within an inexact
5395: Newton method.
5397: Logically Collective
5399: Input Parameters:
5400: + snes - `SNES` context
5401: . version - version 1, 2 (default is 2), 3 or 4
5402: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5403: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5404: . gamma - multiplicative factor for version 2 rtol computation
5405: (0 <= gamma2 <= 1)
5406: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5407: . alpha2 - power for safeguard
5408: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5410: Level: advanced
5412: Notes:
5413: Version 3 was contributed by Luis Chacon, June 2006.
5415: Use `PETSC_CURRENT` to retain the default for any of the parameters.
5417: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`
5418: @*/
5419: PetscErrorCode SNESKSPSetParametersEW(SNES snes, PetscInt version, PetscReal rtol_0, PetscReal rtol_max, PetscReal gamma, PetscReal alpha, PetscReal alpha2, PetscReal threshold)
5420: {
5421: SNESKSPEW *kctx;
5423: PetscFunctionBegin;
5425: kctx = (SNESKSPEW *)snes->kspconvctx;
5426: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5435: if (version != PETSC_CURRENT) kctx->version = version;
5436: if (rtol_0 != (PetscReal)PETSC_CURRENT) kctx->rtol_0 = rtol_0;
5437: if (rtol_max != (PetscReal)PETSC_CURRENT) kctx->rtol_max = rtol_max;
5438: if (gamma != (PetscReal)PETSC_CURRENT) kctx->gamma = gamma;
5439: if (alpha != (PetscReal)PETSC_CURRENT) kctx->alpha = alpha;
5440: if (alpha2 != (PetscReal)PETSC_CURRENT) kctx->alpha2 = alpha2;
5441: if (threshold != (PetscReal)PETSC_CURRENT) kctx->threshold = threshold;
5443: 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);
5444: 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);
5445: 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);
5446: 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);
5447: 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);
5448: 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);
5449: PetscFunctionReturn(PETSC_SUCCESS);
5450: }
5452: /*@
5453: SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5454: convergence criteria for the linear solvers within an inexact
5455: Newton method.
5457: Not Collective
5459: Input Parameter:
5460: . snes - `SNES` context
5462: Output Parameters:
5463: + version - version 1, 2 (default is 2), 3 or 4
5464: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5465: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5466: . gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5467: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5468: . alpha2 - power for safeguard
5469: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5471: Level: advanced
5473: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPSetParametersEW()`
5474: @*/
5475: PetscErrorCode SNESKSPGetParametersEW(SNES snes, PetscInt *version, PetscReal *rtol_0, PetscReal *rtol_max, PetscReal *gamma, PetscReal *alpha, PetscReal *alpha2, PetscReal *threshold)
5476: {
5477: SNESKSPEW *kctx;
5479: PetscFunctionBegin;
5481: kctx = (SNESKSPEW *)snes->kspconvctx;
5482: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5483: if (version) *version = kctx->version;
5484: if (rtol_0) *rtol_0 = kctx->rtol_0;
5485: if (rtol_max) *rtol_max = kctx->rtol_max;
5486: if (gamma) *gamma = kctx->gamma;
5487: if (alpha) *alpha = kctx->alpha;
5488: if (alpha2) *alpha2 = kctx->alpha2;
5489: if (threshold) *threshold = kctx->threshold;
5490: PetscFunctionReturn(PETSC_SUCCESS);
5491: }
5493: PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5494: {
5495: SNES snes = (SNES)ctx;
5496: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5497: PetscReal rtol = PETSC_CURRENT, stol;
5499: PetscFunctionBegin;
5500: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5501: if (!snes->iter) {
5502: rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5503: PetscCall(VecNorm(snes->vec_func, NORM_2, &kctx->norm_first));
5504: } else {
5505: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1-4 are supported: %" PetscInt_FMT, kctx->version);
5506: if (kctx->version == 1) {
5507: rtol = PetscAbsReal(snes->norm - kctx->lresid_last) / kctx->norm_last;
5508: stol = PetscPowReal(kctx->rtol_last, kctx->alpha2);
5509: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5510: } else if (kctx->version == 2) {
5511: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5512: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5513: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5514: } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5515: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5516: /* safeguard: avoid sharp decrease of rtol */
5517: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5518: stol = PetscMax(rtol, stol);
5519: rtol = PetscMin(kctx->rtol_0, stol);
5520: /* safeguard: avoid oversolving */
5521: stol = kctx->gamma * (kctx->norm_first * snes->rtol) / snes->norm;
5522: stol = PetscMax(rtol, stol);
5523: rtol = PetscMin(kctx->rtol_0, stol);
5524: } else /* if (kctx->version == 4) */ {
5525: /* H.-B. An et al. Journal of Computational and Applied Mathematics 200 (2007) 47-60 */
5526: PetscReal ared = PetscAbsReal(kctx->norm_last - snes->norm);
5527: PetscReal pred = PetscAbsReal(kctx->norm_last - kctx->lresid_last);
5528: PetscReal rk = ared / pred;
5529: if (rk < kctx->v4_p1) rtol = 1. - 2. * kctx->v4_p1;
5530: else if (rk < kctx->v4_p2) rtol = kctx->rtol_last;
5531: else if (rk < kctx->v4_p3) rtol = kctx->v4_m1 * kctx->rtol_last;
5532: else rtol = kctx->v4_m2 * kctx->rtol_last;
5534: 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;
5535: kctx->rtol_last_2 = kctx->rtol_last;
5536: kctx->rk_last_2 = kctx->rk_last;
5537: kctx->rk_last = rk;
5538: }
5539: }
5540: /* safeguard: avoid rtol greater than rtol_max */
5541: rtol = PetscMin(rtol, kctx->rtol_max);
5542: PetscCall(KSPSetTolerances(ksp, rtol, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT));
5543: PetscCall(PetscInfo(snes, "iter %" PetscInt_FMT ", Eisenstat-Walker (version %" PetscInt_FMT ") KSP rtol=%g\n", snes->iter, kctx->version, (double)rtol));
5544: PetscFunctionReturn(PETSC_SUCCESS);
5545: }
5547: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5548: {
5549: SNES snes = (SNES)ctx;
5550: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5551: PCSide pcside;
5552: Vec lres;
5554: PetscFunctionBegin;
5555: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5556: PetscCall(KSPGetTolerances(ksp, &kctx->rtol_last, NULL, NULL, NULL));
5557: kctx->norm_last = snes->norm;
5558: if (kctx->version == 1 || kctx->version == 4) {
5559: PC pc;
5560: PetscBool getRes;
5562: PetscCall(KSPGetPC(ksp, &pc));
5563: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCNONE, &getRes));
5564: if (!getRes) {
5565: KSPNormType normtype;
5567: PetscCall(KSPGetNormType(ksp, &normtype));
5568: getRes = (PetscBool)(normtype == KSP_NORM_UNPRECONDITIONED);
5569: }
5570: PetscCall(KSPGetPCSide(ksp, &pcside));
5571: if (pcside == PC_RIGHT || getRes) { /* KSP residual is true linear residual */
5572: PetscCall(KSPGetResidualNorm(ksp, &kctx->lresid_last));
5573: } else {
5574: /* KSP residual is preconditioned residual */
5575: /* compute true linear residual norm */
5576: Mat J;
5577: PetscCall(KSPGetOperators(ksp, &J, NULL));
5578: PetscCall(VecDuplicate(b, &lres));
5579: PetscCall(MatMult(J, x, lres));
5580: PetscCall(VecAYPX(lres, -1.0, b));
5581: PetscCall(VecNorm(lres, NORM_2, &kctx->lresid_last));
5582: PetscCall(VecDestroy(&lres));
5583: }
5584: }
5585: PetscFunctionReturn(PETSC_SUCCESS);
5586: }
5588: /*@
5589: SNESGetKSP - Returns the `KSP` context for a `SNES` solver.
5591: Not Collective, but if `snes` is parallel, then `ksp` is parallel
5593: Input Parameter:
5594: . snes - the `SNES` context
5596: Output Parameter:
5597: . ksp - the `KSP` context
5599: Level: beginner
5601: Notes:
5602: The user can then directly manipulate the `KSP` context to set various
5603: options, etc. Likewise, the user can then extract and manipulate the
5604: `PC` contexts as well.
5606: 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.
5608: .seealso: [](ch_snes), `SNES`, `KSP`, `PC`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
5609: @*/
5610: PetscErrorCode SNESGetKSP(SNES snes, KSP *ksp)
5611: {
5612: PetscFunctionBegin;
5614: PetscAssertPointer(ksp, 2);
5616: if (!snes->ksp) {
5617: PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes), &snes->ksp));
5618: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->ksp, (PetscObject)snes, 1));
5620: PetscCall(KSPSetPreSolve(snes->ksp, KSPPreSolve_SNESEW, snes));
5621: PetscCall(KSPSetPostSolve(snes->ksp, KSPPostSolve_SNESEW, snes));
5623: PetscCall(KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes));
5624: PetscCall(PetscObjectSetOptions((PetscObject)snes->ksp, ((PetscObject)snes)->options));
5625: }
5626: *ksp = snes->ksp;
5627: PetscFunctionReturn(PETSC_SUCCESS);
5628: }
5630: #include <petsc/private/dmimpl.h>
5631: /*@
5632: SNESSetDM - Sets the `DM` that may be used by some `SNES` nonlinear solvers or their underlying preconditioners
5634: Logically Collective
5636: Input Parameters:
5637: + snes - the nonlinear solver context
5638: - dm - the `DM`, cannot be `NULL`
5640: Level: intermediate
5642: Note:
5643: A `DM` can only be used for solving one problem at a time because information about the problem is stored on the `DM`,
5644: even when not using interfaces like `DMSNESSetFunction()`. Use `DMClone()` to get a distinct `DM` when solving different
5645: problems using the same function space.
5647: .seealso: [](ch_snes), `DM`, `SNES`, `SNESGetDM()`, `KSPSetDM()`, `KSPGetDM()`
5648: @*/
5649: PetscErrorCode SNESSetDM(SNES snes, DM dm)
5650: {
5651: KSP ksp;
5652: DMSNES sdm;
5654: PetscFunctionBegin;
5657: PetscCall(PetscObjectReference((PetscObject)dm));
5658: if (snes->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
5659: if (snes->dm->dmsnes && !dm->dmsnes) {
5660: PetscCall(DMCopyDMSNES(snes->dm, dm));
5661: PetscCall(DMGetDMSNES(snes->dm, &sdm));
5662: if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5663: }
5664: PetscCall(DMCoarsenHookRemove(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
5665: PetscCall(DMDestroy(&snes->dm));
5666: }
5667: snes->dm = dm;
5668: snes->dmAuto = PETSC_FALSE;
5670: PetscCall(SNESGetKSP(snes, &ksp));
5671: PetscCall(KSPSetDM(ksp, dm));
5672: PetscCall(KSPSetDMActive(ksp, PETSC_FALSE));
5673: if (snes->npc) {
5674: PetscCall(SNESSetDM(snes->npc, snes->dm));
5675: PetscCall(SNESSetNPCSide(snes, snes->npcside));
5676: }
5677: PetscFunctionReturn(PETSC_SUCCESS);
5678: }
5680: /*@
5681: SNESGetDM - Gets the `DM` that may be used by some `SNES` nonlinear solvers/preconditioners
5683: Not Collective but `dm` obtained is parallel on `snes`
5685: Input Parameter:
5686: . snes - the `SNES` context
5688: Output Parameter:
5689: . dm - the `DM`
5691: Level: intermediate
5693: .seealso: [](ch_snes), `DM`, `SNES`, `SNESSetDM()`, `KSPSetDM()`, `KSPGetDM()`
5694: @*/
5695: PetscErrorCode SNESGetDM(SNES snes, DM *dm)
5696: {
5697: PetscFunctionBegin;
5699: if (!snes->dm) {
5700: PetscCall(DMShellCreate(PetscObjectComm((PetscObject)snes), &snes->dm));
5701: snes->dmAuto = PETSC_TRUE;
5702: }
5703: *dm = snes->dm;
5704: PetscFunctionReturn(PETSC_SUCCESS);
5705: }
5707: /*@
5708: SNESSetNPC - Sets the nonlinear preconditioner to be used.
5710: Collective
5712: Input Parameters:
5713: + snes - iterative context obtained from `SNESCreate()`
5714: - npc - the `SNES` nonlinear preconditioner object
5716: Options Database Key:
5717: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5719: Level: developer
5721: Notes:
5722: This is rarely used, rather use `SNESGetNPC()` to retrieve the preconditioner and configure it using the API.
5724: Only some `SNESType` can use a nonlinear preconditioner
5726: .seealso: [](ch_snes), `SNES`, `SNESNGS`, `SNESFAS`, `SNESGetNPC()`, `SNESHasNPC()`
5727: @*/
5728: PetscErrorCode SNESSetNPC(SNES snes, SNES npc)
5729: {
5730: PetscFunctionBegin;
5733: PetscCheckSameComm(snes, 1, npc, 2);
5734: PetscCall(PetscObjectReference((PetscObject)npc));
5735: PetscCall(SNESDestroy(&snes->npc));
5736: snes->npc = npc;
5737: PetscFunctionReturn(PETSC_SUCCESS);
5738: }
5740: /*@
5741: SNESGetNPC - Gets a nonlinear preconditioning solver SNES` to be used to precondition the original nonlinear solver.
5743: Not Collective; but any changes to the obtained the `pc` object must be applied collectively
5745: Input Parameter:
5746: . snes - iterative context obtained from `SNESCreate()`
5748: Output Parameter:
5749: . pc - the `SNES` preconditioner context
5751: Options Database Key:
5752: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5754: Level: advanced
5756: Notes:
5757: If a `SNES` was previously set with `SNESSetNPC()` then that value is returned, otherwise a new `SNES` object is created that will
5758: be used as the nonlinear preconditioner for the current `SNES`.
5760: The (preconditioner) `SNES` returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5761: `SNES`. These may be overwritten if needed.
5763: Use the options database prefixes `-npc_snes`, `-npc_ksp`, etc., to control the configuration of the nonlinear preconditioner
5765: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESHasNPC()`, `SNES`, `SNESCreate()`
5766: @*/
5767: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5768: {
5769: const char *optionsprefix;
5771: PetscFunctionBegin;
5773: PetscAssertPointer(pc, 2);
5774: if (!snes->npc) {
5775: void *ctx;
5777: PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &snes->npc));
5778: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->npc, (PetscObject)snes, 1));
5779: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5780: PetscCall(SNESSetOptionsPrefix(snes->npc, optionsprefix));
5781: PetscCall(SNESAppendOptionsPrefix(snes->npc, "npc_"));
5782: if (snes->ops->usercompute) {
5783: PetscCall(SNESSetComputeApplicationContext(snes, snes->ops->usercompute, snes->ops->ctxdestroy));
5784: } else {
5785: PetscCall(SNESGetApplicationContext(snes, &ctx));
5786: PetscCall(SNESSetApplicationContext(snes->npc, ctx));
5787: }
5788: PetscCall(SNESSetCountersReset(snes->npc, PETSC_FALSE));
5789: }
5790: *pc = snes->npc;
5791: PetscFunctionReturn(PETSC_SUCCESS);
5792: }
5794: /*@
5795: SNESHasNPC - Returns whether a nonlinear preconditioner is associated with the given `SNES`
5797: Not Collective
5799: Input Parameter:
5800: . snes - iterative context obtained from `SNESCreate()`
5802: Output Parameter:
5803: . has_npc - whether the `SNES` has a nonlinear preconditioner or not
5805: Level: developer
5807: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESGetNPC()`
5808: @*/
5809: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5810: {
5811: PetscFunctionBegin;
5813: PetscAssertPointer(has_npc, 2);
5814: *has_npc = snes->npc ? PETSC_TRUE : PETSC_FALSE;
5815: PetscFunctionReturn(PETSC_SUCCESS);
5816: }
5818: /*@
5819: SNESSetNPCSide - Sets the nonlinear preconditioning side used by the nonlinear preconditioner inside `SNES`.
5821: Logically Collective
5823: Input Parameter:
5824: . snes - iterative context obtained from `SNESCreate()`
5826: Output Parameter:
5827: . side - the preconditioning side, where side is one of
5828: .vb
5829: PC_LEFT - left preconditioning
5830: PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5831: .ve
5833: Options Database Key:
5834: . -snes_npc_side <right,left> - nonlinear preconditioner side
5836: Level: intermediate
5838: Note:
5839: `SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.
5841: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESNRICHARDSON`, `SNESNCG`, `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5842: @*/
5843: PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
5844: {
5845: PetscFunctionBegin;
5848: if (side == PC_SIDE_DEFAULT) side = PC_RIGHT;
5849: PetscCheck((side == PC_LEFT) || (side == PC_RIGHT), PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Only PC_LEFT and PC_RIGHT are supported");
5850: snes->npcside = side;
5851: PetscFunctionReturn(PETSC_SUCCESS);
5852: }
5854: /*@
5855: SNESGetNPCSide - Gets the preconditioning side used by the nonlinear preconditioner inside `SNES`.
5857: Not Collective
5859: Input Parameter:
5860: . snes - iterative context obtained from `SNESCreate()`
5862: Output Parameter:
5863: . side - the preconditioning side, where side is one of
5864: .vb
5865: `PC_LEFT` - left preconditioning
5866: `PC_RIGHT` - right preconditioning (default for most nonlinear solvers)
5867: .ve
5869: Level: intermediate
5871: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESSetNPCSide()`, `KSPGetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5872: @*/
5873: PetscErrorCode SNESGetNPCSide(SNES snes, PCSide *side)
5874: {
5875: PetscFunctionBegin;
5877: PetscAssertPointer(side, 2);
5878: *side = snes->npcside;
5879: PetscFunctionReturn(PETSC_SUCCESS);
5880: }
5882: /*@
5883: SNESSetLineSearch - Sets the `SNESLineSearch` to be used for a given `SNES`
5885: Collective
5887: Input Parameters:
5888: + snes - iterative context obtained from `SNESCreate()`
5889: - linesearch - the linesearch object
5891: Level: developer
5893: Note:
5894: This is almost never used, rather one uses `SNESGetLineSearch()` to retrieve the line search and set options on it
5895: to configure it using the API).
5897: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`
5898: @*/
5899: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5900: {
5901: PetscFunctionBegin;
5904: PetscCheckSameComm(snes, 1, linesearch, 2);
5905: PetscCall(PetscObjectReference((PetscObject)linesearch));
5906: PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5908: snes->linesearch = linesearch;
5909: PetscFunctionReturn(PETSC_SUCCESS);
5910: }
5912: /*@
5913: SNESGetLineSearch - Returns the line search associated with the `SNES`.
5915: Not Collective
5917: Input Parameter:
5918: . snes - iterative context obtained from `SNESCreate()`
5920: Output Parameter:
5921: . linesearch - linesearch context
5923: Level: beginner
5925: Notes:
5926: It creates a default line search instance which can be configured as needed in case it has not been already set with `SNESSetLineSearch()`.
5928: You can also use the options database keys `-snes_linesearch_*` to configure the line search. See `SNESLineSearchSetFromOptions()` for the possible options.
5930: .seealso: [](ch_snes), `SNESLineSearch`, `SNESSetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`
5931: @*/
5932: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5933: {
5934: const char *optionsprefix;
5936: PetscFunctionBegin;
5938: PetscAssertPointer(linesearch, 2);
5939: if (!snes->linesearch) {
5940: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5941: PetscCall(SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch));
5942: PetscCall(SNESLineSearchSetSNES(snes->linesearch, snes));
5943: PetscCall(SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix));
5944: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->linesearch, (PetscObject)snes, 1));
5945: }
5946: *linesearch = snes->linesearch;
5947: PetscFunctionReturn(PETSC_SUCCESS);
5948: }