Actual source code: snes.c
1: #include <petsc/private/snesimpl.h>
2: #include <petsc/private/linesearchimpl.h>
3: #include <petscdmshell.h>
4: #include <petscdraw.h>
5: #include <petscds.h>
6: #include <petscdmadaptor.h>
7: #include <petscconvest.h>
9: PetscBool SNESRegisterAllCalled = PETSC_FALSE;
10: PetscFunctionList SNESList = NULL;
12: /* Logging support */
13: PetscClassId SNES_CLASSID, DMSNES_CLASSID;
14: PetscLogEvent SNES_Solve, SNES_SetUp, SNES_FunctionEval, SNES_JacobianEval, SNES_NGSEval, SNES_NGSFuncEval, SNES_NewtonALEval, SNES_NPCSolve, SNES_ObjectiveEval;
16: /*@
17: SNESSetErrorIfNotConverged - Causes `SNESSolve()` to generate an error immediately if the solver has not converged.
19: Logically Collective
21: Input Parameters:
22: + snes - iterative context obtained from `SNESCreate()`
23: - flg - `PETSC_TRUE` indicates you want the error generated
25: Options Database Key:
26: . -snes_error_if_not_converged (true|false) - cause an immediate error condition and stop the program if the solver does not converge
28: Level: intermediate
30: Note:
31: Normally PETSc continues if a solver fails to converge, you can call `SNESGetConvergedReason()` after a `SNESSolve()`
32: to determine if it has converged. Otherwise the solution may be inaccurate or wrong
34: .seealso: [](ch_snes), `SNES`, `SNESGetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
35: @*/
36: PetscErrorCode SNESSetErrorIfNotConverged(SNES snes, PetscBool flg)
37: {
38: PetscFunctionBegin;
41: snes->errorifnotconverged = flg;
42: PetscFunctionReturn(PETSC_SUCCESS);
43: }
45: /*@
46: SNESGetErrorIfNotConverged - Indicates if `SNESSolve()` will generate an error if the solver does not converge?
48: Not Collective
50: Input Parameter:
51: . snes - iterative context obtained from `SNESCreate()`
53: Output Parameter:
54: . flag - `PETSC_TRUE` if it will generate an error, else `PETSC_FALSE`
56: Level: intermediate
58: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
59: @*/
60: PetscErrorCode SNESGetErrorIfNotConverged(SNES snes, PetscBool *flag)
61: {
62: PetscFunctionBegin;
64: PetscAssertPointer(flag, 2);
65: *flag = snes->errorifnotconverged;
66: PetscFunctionReturn(PETSC_SUCCESS);
67: }
69: /*@
70: SNESSetAlwaysComputesFinalResidual - tells the `SNES` to always compute the residual (nonlinear function value) at the final solution
72: Logically Collective
74: Input Parameters:
75: + snes - the shell `SNES`
76: - flg - `PETSC_TRUE` to always compute the residual
78: Level: advanced
80: Note:
81: Some solvers (such as smoothers in a `SNESFAS`) do not need the residual computed at the final solution so skip computing it
82: to save time.
84: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSolve()`, `SNESGetAlwaysComputesFinalResidual()`
85: @*/
86: PetscErrorCode SNESSetAlwaysComputesFinalResidual(SNES snes, PetscBool flg)
87: {
88: PetscFunctionBegin;
90: snes->alwayscomputesfinalresidual = flg;
91: PetscFunctionReturn(PETSC_SUCCESS);
92: }
94: /*@
95: SNESGetAlwaysComputesFinalResidual - checks if the `SNES` always computes the residual at the final solution
97: Logically Collective
99: Input Parameter:
100: . snes - the `SNES` context
102: Output Parameter:
103: . flg - `PETSC_TRUE` if the residual is computed
105: Level: advanced
107: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSolve()`, `SNESSetAlwaysComputesFinalResidual()`
108: @*/
109: PetscErrorCode SNESGetAlwaysComputesFinalResidual(SNES snes, PetscBool *flg)
110: {
111: PetscFunctionBegin;
113: *flg = snes->alwayscomputesfinalresidual;
114: PetscFunctionReturn(PETSC_SUCCESS);
115: }
117: /*@
118: SNESSetFunctionDomainError - tells `SNES` that the input vector, a proposed new solution, to your function you provided to `SNESSetFunction()` is not
119: in the function's domain. For example, a step with negative pressure.
121: Not Collective
123: Input Parameter:
124: . snes - the `SNES` context
126: Level: advanced
128: Notes:
129: This does not need to be called by all processes in the `SNES` MPI communicator.
131: A few solvers will try to cut the step size to avoid the domain error but for other solvers `SNESSolve()` stops iterating and
132: returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
134: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
135: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
137: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
139: You can call `SNESSetJacobianDomainError()` during a Jacobian computation to indicate the proposed solution is not in the domain.
141: Developer Note:
142: This value is used by `SNESCheckFunctionDomainError()` to determine if the `SNESConvergedReason` is set to `SNES_DIVERGED_FUNCTION_DOMAIN`
144: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetJacobianDomainError()`, `SNESVISetVariableBounds()`,
145: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`,
146: `SNES_DIVERGED_FUNCTION_DOMAIN`, `SNESSetObjectiveDomainError()`, `SNES_DIVERGED_OBJECTIVE_DOMAIN`
147: @*/
148: PetscErrorCode SNESSetFunctionDomainError(SNES snes)
149: {
150: PetscFunctionBegin;
152: snes->functiondomainerror = PETSC_TRUE;
153: PetscFunctionReturn(PETSC_SUCCESS);
154: }
156: /*@
157: SNESSetObjectiveDomainError - tells `SNES` that the input vector, a proposed new solution, to your function you provided to `SNESSetObjective()` is not
158: in the function's domain. For example, a step with negative pressure.
160: Not Collective
162: Input Parameter:
163: . snes - the `SNES` context
165: Level: advanced
167: Notes:
168: This does not need to be called by all processes in the `SNES` MPI communicator.
170: A few solvers will try to cut the step size to avoid the domain error but for other solvers `SNESSolve()` stops iterating and
171: returns with a `SNESConvergedReason` of `SNES_DIVERGED_OBJECTIVE_DOMAIN`
173: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
174: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
176: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
178: You can call `SNESSetJacobianDomainError()` during a Jacobian computation to indicate the proposed solution is not in the domain.
180: Developer Note:
181: This value is used by `SNESCheckObjectiveDomainError()` to determine if the `SNESConvergedReason` is set to `SNES_DIVERGED_OBJECTIVE_DOMAIN`
183: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetJacobianDomainError()`, `SNESVISetVariableBounds()`,
184: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`,
185: `SNES_DIVERGED_OBJECTIVE_DOMAIN`, `SNESSetFunctionDomainError()`, `SNES_DIVERGED_FUNCTION_DOMAIN`
186: @*/
187: PetscErrorCode SNESSetObjectiveDomainError(SNES snes)
188: {
189: PetscFunctionBegin;
191: snes->objectivedomainerror = PETSC_TRUE;
192: PetscFunctionReturn(PETSC_SUCCESS);
193: }
195: /*@
196: SNESSetJacobianDomainError - tells `SNES` that the function you provided to `SNESSetJacobian()` at the proposed step. For example there is a negative element transformation.
198: Logically Collective
200: Input Parameter:
201: . snes - the `SNES` context
203: Level: advanced
205: Notes:
206: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_JACOBIAN_DOMAIN`
208: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
210: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
211: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
213: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESVISetVariableBounds()`,
214: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`
215: @*/
216: PetscErrorCode SNESSetJacobianDomainError(SNES snes)
217: {
218: PetscFunctionBegin;
220: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates computeJacobian does not make sense");
221: snes->jacobiandomainerror = PETSC_TRUE;
222: PetscFunctionReturn(PETSC_SUCCESS);
223: }
225: /*@
226: SNESSetCheckJacobianDomainError - tells `SNESSolve()` whether to check if the user called `SNESSetJacobianDomainError()` to indicate a Jacobian domain error after
227: each Jacobian evaluation.
229: Logically Collective
231: Input Parameters:
232: + snes - the `SNES` context
233: - flg - indicates if or not to check Jacobian domain error after each Jacobian evaluation
235: Level: advanced
237: Notes:
238: By default, it checks for the Jacobian domain error in the debug mode, and does not check it in the optimized mode.
240: Checks require one extra parallel synchronization for each Jacobian evaluation
242: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESGetCheckJacobianDomainError()`
243: @*/
244: PetscErrorCode SNESSetCheckJacobianDomainError(SNES snes, PetscBool flg)
245: {
246: PetscFunctionBegin;
248: snes->checkjacdomainerror = flg;
249: PetscFunctionReturn(PETSC_SUCCESS);
250: }
252: /*@
253: SNESGetCheckJacobianDomainError - Get an indicator whether or not `SNES` is checking Jacobian domain errors after each Jacobian evaluation.
255: Logically Collective
257: Input Parameter:
258: . snes - the `SNES` context
260: Output Parameter:
261: . flg - `PETSC_FALSE` indicates that it is not checking Jacobian domain errors after each Jacobian evaluation
263: Level: advanced
265: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESSetCheckJacobianDomainError()`
266: @*/
267: PetscErrorCode SNESGetCheckJacobianDomainError(SNES snes, PetscBool *flg)
268: {
269: PetscFunctionBegin;
271: PetscAssertPointer(flg, 2);
272: *flg = snes->checkjacdomainerror;
273: PetscFunctionReturn(PETSC_SUCCESS);
274: }
276: /*@
277: SNESLoad - Loads a `SNES` that has been stored in `PETSCVIEWERBINARY` with `SNESView()`.
279: Collective
281: Input Parameters:
282: + snes - the newly loaded `SNES`, this needs to have been created with `SNESCreate()` or
283: some related function before a call to `SNESLoad()`.
284: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()`
286: Level: intermediate
288: Note:
289: The `SNESType` is determined by the data in the file, any type set into the `SNES` before this call is ignored.
291: .seealso: [](ch_snes), `SNES`, `PetscViewer`, `SNESCreate()`, `SNESType`, `PetscViewerBinaryOpen()`, `SNESView()`, `MatLoad()`, `VecLoad()`
292: @*/
293: PetscErrorCode SNESLoad(SNES snes, PetscViewer viewer)
294: {
295: PetscBool isbinary;
296: PetscInt classid;
297: char type[256];
298: KSP ksp;
299: DM dm;
300: DMSNES dmsnes;
302: PetscFunctionBegin;
305: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
306: PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
308: PetscCall(PetscViewerBinaryRead(viewer, &classid, 1, NULL, PETSC_INT));
309: PetscCheck(classid == SNES_FILE_CLASSID, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Not SNES next in file");
310: PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
311: PetscCall(SNESSetType(snes, type));
312: PetscTryTypeMethod(snes, load, viewer);
313: PetscCall(SNESGetDM(snes, &dm));
314: PetscCall(DMGetDMSNES(dm, &dmsnes));
315: PetscCall(DMSNESLoad(dmsnes, viewer));
316: PetscCall(SNESGetKSP(snes, &ksp));
317: PetscCall(KSPLoad(ksp, viewer));
318: PetscFunctionReturn(PETSC_SUCCESS);
319: }
321: #include <petscdraw.h>
322: #if PetscDefined(HAVE_SAWS)
323: #include <petscviewersaws.h>
324: #endif
326: /*@
327: SNESViewFromOptions - View a `SNES` based on values in the options database
329: Collective
331: Input Parameters:
332: + A - the `SNES` context
333: . obj - Optional object that provides the options prefix for the checks
334: - name - command line option
336: Options Database Key:
337: . -name [viewertype][:...] - option name and values. See `PetscObjectViewFromOptions()` for the possible arguments
339: Level: intermediate
341: .seealso: [](ch_snes), `SNES`, `SNESView`, `PetscObjectViewFromOptions()`, `SNESCreate()`
342: @*/
343: PetscErrorCode SNESViewFromOptions(SNES A, PetscObject obj, const char name[])
344: {
345: PetscFunctionBegin;
347: PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
348: PetscFunctionReturn(PETSC_SUCCESS);
349: }
351: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES, Vec, Mat, Mat, void *);
353: /*@
354: SNESView - Prints or visualizes the `SNES` data structure.
356: Collective
358: Input Parameters:
359: + snes - the `SNES` context
360: - viewer - the `PetscViewer`
362: Options Database Key:
363: . -snes_view - Calls `SNESView()` at end of `SNESSolve()`
365: Level: beginner
367: Notes:
368: The available visualization contexts include
369: + `PETSC_VIEWER_STDOUT_SELF` - standard output (default)
370: - `PETSC_VIEWER_STDOUT_WORLD` - synchronized standard
371: output where only the first processor opens
372: the file. All other processors send their
373: data to the first processor to print.
375: The available formats include
376: + `PETSC_VIEWER_DEFAULT` - standard output (default)
377: - `PETSC_VIEWER_ASCII_INFO_DETAIL` - more verbose output for `SNESNASM`
379: The user can open an alternative visualization context with
380: `PetscViewerASCIIOpen()` - output to a specified file.
382: In the debugger you can do "call `SNESView`(snes,0)" to display the `SNES` solver. (The same holds for any PETSc object viewer).
384: .seealso: [](ch_snes), `SNES`, `SNESLoad()`, `SNESCreate()`, `PetscViewerASCIIOpen()`
385: @*/
386: PetscErrorCode SNESView(SNES snes, PetscViewer viewer)
387: {
388: SNESKSPEW *kctx;
389: KSP ksp;
390: Vec u;
391: SNESLineSearch linesearch;
392: PetscBool isascii, isstring, isbinary, isdraw;
393: DMSNES dmsnes;
394: #if PetscDefined(HAVE_SAWS)
395: PetscBool issaws;
396: #endif
398: PetscFunctionBegin;
400: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &viewer));
402: PetscCheckSameComm(snes, 1, viewer, 2);
404: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
405: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
406: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
407: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
408: #if PetscDefined(HAVE_SAWS)
409: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
410: #endif
411: if (isascii) {
412: SNESNormSchedule normschedule;
413: DM dm;
414: SNESJacobianFn *cJ;
415: void *ctx;
416: const char *pre = "";
418: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)snes, viewer));
419: if (!snes->setupcalled) PetscCall(PetscViewerASCIIPrintf(viewer, " SNES has not been set up so information may be incomplete\n"));
420: if (snes->ops->view) {
421: PetscCall(PetscViewerASCIIPushTab(viewer));
422: PetscUseTypeMethod(snes, view, viewer);
423: PetscCall(PetscViewerASCIIPopTab(viewer));
424: }
425: if (snes->max_funcs == PETSC_UNLIMITED) {
426: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=unlimited\n", snes->max_its));
427: } else {
428: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=%" PetscInt_FMT "\n", snes->max_its, snes->max_funcs));
429: }
430: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%g, absolute=%g, solution=%g\n", (double)snes->rtol, (double)snes->abstol, (double)snes->stol));
431: if (snes->usesksp) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of linear solver iterations=%" PetscInt_FMT "\n", snes->linear_its));
432: PetscCall(PetscViewerASCIIPrintf(viewer, " total number of function evaluations=%" PetscInt_FMT "\n", snes->nfuncs));
433: PetscCall(SNESGetNormSchedule(snes, &normschedule));
434: if (normschedule > 0) PetscCall(PetscViewerASCIIPrintf(viewer, " norm schedule %s\n", SNESNormSchedules[normschedule]));
435: if (snes->gridsequence) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of grid sequence refinements=%" PetscInt_FMT "\n", snes->gridsequence));
436: if (snes->ksp_ewconv) {
437: kctx = (SNESKSPEW *)snes->kspconvctx;
438: if (kctx) {
439: PetscCall(PetscViewerASCIIPrintf(viewer, " Eisenstat-Walker computation of KSP relative tolerance (version %" PetscInt_FMT ")\n", kctx->version));
440: PetscCall(PetscViewerASCIIPrintf(viewer, " rtol_0=%g, rtol_max=%g, threshold=%g\n", (double)kctx->rtol_0, (double)kctx->rtol_max, (double)kctx->threshold));
441: PetscCall(PetscViewerASCIIPrintf(viewer, " gamma=%g, alpha=%g, alpha2=%g\n", (double)kctx->gamma, (double)kctx->alpha, (double)kctx->alpha2));
442: }
443: }
444: if (snes->lagpreconditioner == -1) {
445: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is never rebuilt\n"));
446: } else if (snes->lagpreconditioner > 1) {
447: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is rebuilt every %" PetscInt_FMT " new Jacobians\n", snes->lagpreconditioner));
448: }
449: if (snes->lagjacobian == -1) {
450: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is never rebuilt\n"));
451: } else if (snes->lagjacobian > 1) {
452: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is rebuilt every %" PetscInt_FMT " SNES iterations\n", snes->lagjacobian));
453: }
454: PetscCall(SNESGetDM(snes, &dm));
455: PetscCall(DMSNESGetJacobian(dm, &cJ, &ctx));
456: if (snes->mf_operator) {
457: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing\n"));
458: pre = "Preconditioning ";
459: }
460: if (cJ == SNESComputeJacobianDefault) {
461: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences one column at a time\n", pre));
462: } else if (cJ == SNESComputeJacobianDefaultColor) {
463: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences with coloring\n", pre));
464: /* it slightly breaks data encapsulation for access the DMDA information directly */
465: } else if (cJ == SNESComputeJacobian_DMDA) {
466: MatFDColoring fdcoloring;
467: PetscCall(PetscObjectQuery((PetscObject)dm, "DMDASNES_FDCOLORING", (PetscObject *)&fdcoloring));
468: if (fdcoloring) {
469: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using colored finite differences on a DMDA\n", pre));
470: } else {
471: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using a DMDA local Jacobian\n", pre));
472: }
473: } else if (snes->mf && !snes->mf_operator) {
474: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing, no explicit Jacobian\n"));
475: }
476: } else if (isstring) {
477: const char *type;
478: PetscCall(SNESGetType(snes, &type));
479: PetscCall(PetscViewerStringSPrintf(viewer, " SNESType: %-7.7s", type));
480: PetscTryTypeMethod(snes, view, viewer);
481: } else if (isbinary) {
482: PetscInt classid = SNES_FILE_CLASSID;
483: MPI_Comm comm;
484: PetscMPIInt rank;
485: char type[256];
487: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
488: PetscCallMPI(MPI_Comm_rank(comm, &rank));
489: if (rank == 0) {
490: PetscCall(PetscViewerBinaryWrite(viewer, &classid, 1, PETSC_INT));
491: PetscCall(PetscStrncpy(type, ((PetscObject)snes)->type_name, sizeof(type)));
492: PetscCall(PetscViewerBinaryWrite(viewer, type, sizeof(type), PETSC_CHAR));
493: }
494: PetscTryTypeMethod(snes, view, viewer);
495: } else if (isdraw) {
496: PetscDraw draw;
497: char str[36];
498: PetscReal x, y, bottom, h;
500: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
501: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
502: PetscCall(PetscStrncpy(str, "SNES: ", sizeof(str)));
503: PetscCall(PetscStrlcat(str, ((PetscObject)snes)->type_name, sizeof(str)));
504: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_BLUE, PETSC_DRAW_BLACK, str, NULL, &h));
505: bottom = y - h;
506: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
507: PetscTryTypeMethod(snes, view, viewer);
508: #if PetscDefined(HAVE_SAWS)
509: } else if (issaws) {
510: PetscMPIInt rank;
511: const char *name;
513: PetscCall(PetscObjectGetName((PetscObject)snes, &name));
514: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
515: if (!((PetscObject)snes)->amsmem && rank == 0) {
516: char dir[1024];
518: PetscCall(PetscObjectViewSAWs((PetscObject)snes, viewer));
519: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/its", name));
520: PetscCallSAWs(SAWs_Register, (dir, &snes->iter, 1, SAWs_READ, SAWs_INT));
521: if (!snes->conv_hist) PetscCall(SNESSetConvergenceHistory(snes, NULL, NULL, PETSC_DECIDE, PETSC_TRUE));
522: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/conv_hist", name));
523: PetscCallSAWs(SAWs_Register, (dir, snes->conv_hist, 10, SAWs_READ, SAWs_DOUBLE));
524: }
525: #endif
526: }
527: if (snes->linesearch) {
528: PetscCall(SNESGetLineSearch(snes, &linesearch));
529: PetscCall(PetscViewerASCIIPushTab(viewer));
530: PetscCall(SNESLineSearchView(linesearch, viewer));
531: PetscCall(PetscViewerASCIIPopTab(viewer));
532: }
533: if (snes->npc && snes->usesnpc) {
534: PetscCall(PetscViewerASCIIPushTab(viewer));
535: PetscCall(SNESView(snes->npc, viewer));
536: PetscCall(PetscViewerASCIIPopTab(viewer));
537: }
538: PetscCall(PetscViewerASCIIPushTab(viewer));
539: PetscCall(DMGetDMSNES(snes->dm, &dmsnes));
540: PetscCall(DMSNESView(dmsnes, viewer));
541: PetscCall(PetscViewerASCIIPopTab(viewer));
542: if (snes->usesksp) {
543: PetscCall(SNESGetKSP(snes, &ksp));
544: PetscCall(PetscViewerASCIIPushTab(viewer));
545: PetscCall(KSPView(ksp, viewer));
546: PetscCall(PetscViewerASCIIPopTab(viewer));
547: } else {
548: PetscViewerFormat format;
550: PetscCall(SNESGetSolution(snes, &u));
551: PetscCall(PetscViewerGetFormat(viewer, &format));
552: if (u && isascii) {
553: if (format != PETSC_VIEWER_ASCII_INFO_DETAIL) PetscCall(PetscViewerPushFormat(viewer, PETSC_VIEWER_ASCII_INFO));
554: PetscCall(PetscViewerASCIIPrintf(viewer, "solution vector:\n"));
555: PetscCall(PetscViewerASCIIPushTab(viewer));
556: PetscCall(VecView(u, viewer));
557: PetscCall(PetscViewerASCIIPopTab(viewer));
558: if (format != PETSC_VIEWER_ASCII_INFO_DETAIL) PetscCall(PetscViewerPopFormat(viewer));
559: }
560: }
561: if (isdraw) {
562: PetscDraw draw;
563: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
564: PetscCall(PetscDrawPopCurrentPoint(draw));
565: }
566: PetscFunctionReturn(PETSC_SUCCESS);
567: }
569: /*
570: We retain a list of functions that also take SNES command
571: line options. These are called at the end SNESSetFromOptions()
572: */
573: #define MAXSETFROMOPTIONS 5
574: static PetscInt numberofsetfromoptions;
575: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);
577: /*@
578: SNESAddOptionsChecker - Adds an additional function to check for `SNES` options.
580: Not Collective
582: Input Parameter:
583: . snescheck - function that checks for options
585: Calling sequence of `snescheck`:
586: . snes - the `SNES` object for which it is checking options
588: Level: developer
590: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`
591: @*/
592: PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES snes))
593: {
594: PetscFunctionBegin;
595: PetscCheck(numberofsetfromoptions < MAXSETFROMOPTIONS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %d allowed", MAXSETFROMOPTIONS);
596: othersetfromoptions[numberofsetfromoptions++] = snescheck;
597: PetscFunctionReturn(PETSC_SUCCESS);
598: }
600: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
601: {
602: Mat J;
603: MatNullSpace nullsp;
605: PetscFunctionBegin;
608: if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
609: Mat A = snes->jacobian, B = snes->jacobian_pre;
610: PetscCall(MatCreateVecs(A ? A : B, NULL, &snes->vec_func));
611: }
613: PetscCheck(version == 1 || version == 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator routines, only version 1 and 2");
614: if (version == 1) {
615: PetscCall(MatCreateSNESMF(snes, &J));
616: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
617: PetscCall(MatSetFromOptions(J));
618: /* TODO: the version 2 code should be merged into the MatCreateSNESMF() and MatCreateMFFD() infrastructure and then removed */
619: } else /* if (version == 2) */ {
620: PetscCheck(snes->vec_func, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "SNESSetFunction() must be called first");
621: #if !PetscDefined(USE_COMPLEX) && !PetscDefined(USE_REAL_SINGLE) && !PetscDefined(USE_REAL___FLOAT128) && !PetscDefined(USE_REAL___FP16)
622: PetscCall(MatCreateSNESMFMore(snes, snes->vec_func, &J));
623: #else
624: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "matrix-free operator routines (version 2)");
625: #endif
626: }
628: /* attach any user provided null space that was on Amat to the newly created matrix-free matrix */
629: if (snes->jacobian) {
630: PetscCall(MatGetNullSpace(snes->jacobian, &nullsp));
631: if (nullsp) PetscCall(MatSetNullSpace(J, nullsp));
632: }
634: PetscCall(PetscInfo(snes, "Setting default matrix-free operator routines (version %" PetscInt_FMT ")\n", version));
635: if (hasOperator) {
636: /* This version replaces the user provided Jacobian matrix with a
637: matrix-free version but still employs the user-provided matrix used for computing the preconditioner. */
638: PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
639: } else {
640: /* This version replaces both the user-provided Jacobian and the user-
641: provided preconditioner Jacobian with the default matrix-free version. */
642: if (snes->npcside == PC_LEFT && snes->npc) {
643: if (!snes->jacobian) PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
644: } else PetscCall(SNESSetJacobian(snes, J, J, MatMFFDComputeJacobian, NULL));
645: }
646: PetscCall(MatDestroy(&J));
647: PetscFunctionReturn(PETSC_SUCCESS);
648: }
650: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine, Mat Restrict, Vec Rscale, Mat Inject, DM dmcoarse, PetscCtx ctx)
651: {
652: SNES snes = (SNES)ctx;
653: Vec Xfine, Xfine_named = NULL, Xcoarse;
655: PetscFunctionBegin;
656: if (PetscLogPrintInfo) {
657: PetscInt finelevel, coarselevel, fineclevel, coarseclevel;
658: PetscCall(DMGetRefineLevel(dmfine, &finelevel));
659: PetscCall(DMGetCoarsenLevel(dmfine, &fineclevel));
660: PetscCall(DMGetRefineLevel(dmcoarse, &coarselevel));
661: PetscCall(DMGetCoarsenLevel(dmcoarse, &coarseclevel));
662: PetscCall(PetscInfo(dmfine, "Restricting SNES solution vector from level %" PetscInt_FMT "-%" PetscInt_FMT " to level %" PetscInt_FMT "-%" PetscInt_FMT "\n", finelevel, fineclevel, coarselevel, coarseclevel));
663: }
664: if (dmfine == snes->dm) Xfine = snes->vec_sol;
665: else {
666: PetscCall(DMGetNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
667: Xfine = Xfine_named;
668: }
669: PetscCall(DMGetNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
670: if (Inject) {
671: PetscCall(MatRestrict(Inject, Xfine, Xcoarse));
672: } else {
673: PetscCall(MatRestrict(Restrict, Xfine, Xcoarse));
674: PetscCall(VecPointwiseMult(Xcoarse, Xcoarse, Rscale));
675: }
676: PetscCall(DMRestoreNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
677: if (Xfine_named) PetscCall(DMRestoreNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
678: PetscFunctionReturn(PETSC_SUCCESS);
679: }
681: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm, DM dmc, PetscCtx ctx)
682: {
683: PetscFunctionBegin;
684: PetscCall(DMCoarsenHookAdd(dmc, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, ctx));
685: PetscFunctionReturn(PETSC_SUCCESS);
686: }
688: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
689: * safely call SNESGetDM() in their residual evaluation routine. */
690: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp, Mat A, Mat B, PetscCtx ctx)
691: {
692: SNES snes = (SNES)ctx;
693: DMSNES sdm;
694: Vec X, Xnamed = NULL;
695: DM dmsave;
696: void *ctxsave;
697: SNESJacobianFn *jac = NULL;
699: PetscFunctionBegin;
700: dmsave = snes->dm;
701: PetscCall(KSPGetDM(ksp, &snes->dm));
702: if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
703: else {
704: PetscBool has;
706: /* We are on a coarser level, this vec was initialized using a DM restrict hook */
707: PetscCall(DMHasNamedGlobalVector(snes->dm, "SNESVecSol", &has));
708: PetscCheck(has, PetscObjectComm((PetscObject)snes->dm), PETSC_ERR_PLIB, "Missing SNESVecSol");
709: PetscCall(DMGetNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
710: X = Xnamed;
711: PetscCall(SNESGetJacobian(snes, NULL, NULL, &jac, &ctxsave));
712: /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
713: if (jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, SNESComputeJacobianDefaultColor, NULL));
714: }
716: /* Compute the operators */
717: PetscCall(DMGetDMSNES(snes->dm, &sdm));
718: if (Xnamed && sdm->ops->computefunction) {
719: /* The SNES contract with the user is that ComputeFunction is always called before ComputeJacobian.
720: We make sure of this here. Disable affine shift since it is for the finest level */
721: Vec F, saverhs = snes->vec_rhs;
723: snes->vec_rhs = NULL;
724: PetscCall(DMGetGlobalVector(snes->dm, &F));
725: PetscCall(SNESComputeFunction(snes, X, F));
726: PetscCall(DMRestoreGlobalVector(snes->dm, &F));
727: snes->vec_rhs = saverhs;
728: snes->nfuncs--; /* Do not log coarser level evaluations */
729: }
730: /* Make sure KSP DM has the Jacobian computation routine */
731: if (!sdm->ops->computejacobian) PetscCall(DMCopyDMSNES(dmsave, snes->dm));
732: PetscCall(SNESComputeJacobian(snes, X, A, B)); /* cannot handle previous SNESSetJacobianDomainError() calls */
734: /* Put the previous context back */
735: if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, jac, ctxsave));
737: if (Xnamed) PetscCall(DMRestoreNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
738: snes->dm = dmsave;
739: PetscFunctionReturn(PETSC_SUCCESS);
740: }
742: /*@
743: SNESSetUpMatrices - ensures that matrices are available for `SNES` Newton-like methods, this is called by `SNESSetUp_XXX()`
745: Collective
747: Input Parameter:
748: . snes - `SNES` object to configure
750: Level: developer
752: Note:
753: If the matrices do not yet exist it attempts to create them based on options previously set for the `SNES` such as `-snes_mf`
755: Developer Note:
756: The functionality of this routine overlaps in a confusing way with the functionality of `SNESSetUpMatrixFree_Private()` which is called by
757: `SNESSetUp()` but sometimes `SNESSetUpMatrices()` is called without `SNESSetUp()` being called. A refactorization to simplify the
758: logic that handles the matrix-free case is desirable.
760: .seealso: [](ch_snes), `SNES`, `SNESSetUp()`
761: @*/
762: PetscErrorCode SNESSetUpMatrices(SNES snes)
763: {
764: DM dm;
765: DMSNES sdm;
767: PetscFunctionBegin;
768: PetscCall(SNESGetDM(snes, &dm));
769: PetscCall(DMGetDMSNES(dm, &sdm));
770: if (!snes->jacobian && snes->mf && !snes->mf_operator && !snes->jacobian_pre) {
771: Mat J;
772: void *functx;
773: PetscCall(MatCreateSNESMF(snes, &J));
774: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
775: PetscCall(MatSetFromOptions(J));
776: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
777: PetscCall(SNESSetJacobian(snes, J, J, NULL, NULL));
778: PetscCall(MatDestroy(&J));
779: } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
780: Mat J, B;
781: PetscCall(MatCreateSNESMF(snes, &J));
782: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
783: PetscCall(MatSetFromOptions(J));
784: PetscCall(DMCreateMatrix(snes->dm, &B));
785: /* sdm->computejacobian was already set to reach here */
786: PetscCall(SNESSetJacobian(snes, J, B, NULL, NULL));
787: PetscCall(MatDestroy(&J));
788: PetscCall(MatDestroy(&B));
789: } else if (!snes->jacobian_pre) {
790: PetscDS prob;
791: Mat J, B;
792: PetscBool hasPrec = PETSC_FALSE;
794: J = snes->jacobian;
795: PetscCall(DMGetDS(dm, &prob));
796: if (prob) PetscCall(PetscDSHasJacobianPreconditioner(prob, &hasPrec));
797: if (!J && hasPrec) PetscCall(DMCreateMatrix(snes->dm, &J));
798: else PetscCall(PetscObjectReference((PetscObject)J));
799: PetscCall(DMCreateMatrix(snes->dm, &B));
800: PetscCall(SNESSetJacobian(snes, J ? J : B, B, NULL, NULL));
801: PetscCall(MatDestroy(&J));
802: PetscCall(MatDestroy(&B));
803: }
804: {
805: KSP ksp;
806: PetscCall(SNESGetKSP(snes, &ksp));
807: PetscCall(KSPSetComputeOperators(ksp, KSPComputeOperators_SNES, snes));
808: PetscCall(DMCoarsenHookAdd(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
809: }
810: PetscFunctionReturn(PETSC_SUCCESS);
811: }
813: PETSC_SINGLE_LIBRARY_INTERN PetscErrorCode PetscMonitorPauseFinal_Internal(PetscInt, PetscCtx);
815: static PetscErrorCode SNESMonitorPauseFinal_Internal(SNES snes)
816: {
817: PetscFunctionBegin;
818: if (!snes->pauseFinal) PetscFunctionReturn(PETSC_SUCCESS);
819: PetscCall(PetscMonitorPauseFinal_Internal(snes->numbermonitors, snes->monitorcontext));
820: PetscFunctionReturn(PETSC_SUCCESS);
821: }
823: /*@
824: SNESMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user
826: Collective
828: Input Parameters:
829: + snes - `SNES` object you wish to monitor
830: . name - the monitor type one is seeking
831: . help - message indicating what monitoring is done
832: . manual - manual page for the monitor
833: . monitor - the monitor function, this must use a `PetscViewerFormat` as its context
834: - 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
836: Calling sequence of `monitor`:
837: + snes - the nonlinear solver context
838: . it - the current iteration
839: . r - the current function norm
840: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
842: Calling sequence of `monitorsetup`:
843: + snes - the nonlinear solver context
844: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
846: Options Database Key:
847: . -name - trigger the use of this monitor in `SNESSetFromOptions()`
849: Level: advanced
851: .seealso: [](ch_snes), `PetscOptionsCreateViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
852: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`,
853: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
854: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
855: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
856: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
857: `PetscOptionsFList()`, `PetscOptionsEList()`
858: @*/
859: 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))
860: {
861: PetscViewer viewer;
862: PetscViewerFormat format;
863: PetscBool flg;
865: PetscFunctionBegin;
866: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, name, &viewer, &format, &flg));
867: if (flg) {
868: PetscViewerAndFormat *vf;
869: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
870: PetscCall(PetscViewerDestroy(&viewer));
871: if (monitorsetup) PetscCall((*monitorsetup)(snes, vf));
872: PetscCall(SNESMonitorSet(snes, (PetscErrorCode (*)(SNES, PetscInt, PetscReal, PetscCtx))monitor, vf, (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy));
873: }
874: PetscFunctionReturn(PETSC_SUCCESS);
875: }
877: PetscErrorCode SNESEWSetFromOptions_Private(SNESKSPEW *kctx, PetscBool print_api, MPI_Comm comm, const char *prefix)
878: {
879: const char *api = print_api ? "SNESKSPSetParametersEW" : NULL;
881: PetscFunctionBegin;
882: PetscOptionsBegin(comm, prefix, "Eisenstat and Walker type forcing options", "KSP");
883: PetscCall(PetscOptionsInt("-ksp_ew_version", "Version 1, 2 or 3", api, kctx->version, &kctx->version, NULL));
884: PetscCall(PetscOptionsReal("-ksp_ew_rtol0", "0 <= rtol0 < 1", api, kctx->rtol_0, &kctx->rtol_0, NULL));
885: kctx->rtol_max = PetscMax(kctx->rtol_0, kctx->rtol_max);
886: PetscCall(PetscOptionsReal("-ksp_ew_rtolmax", "0 <= rtolmax < 1", api, kctx->rtol_max, &kctx->rtol_max, NULL));
887: PetscCall(PetscOptionsReal("-ksp_ew_gamma", "0 <= gamma <= 1", api, kctx->gamma, &kctx->gamma, NULL));
888: PetscCall(PetscOptionsReal("-ksp_ew_alpha", "1 < alpha <= 2", api, kctx->alpha, &kctx->alpha, NULL));
889: PetscCall(PetscOptionsReal("-ksp_ew_alpha2", "alpha2", NULL, kctx->alpha2, &kctx->alpha2, NULL));
890: PetscCall(PetscOptionsReal("-ksp_ew_threshold", "0 < threshold < 1", api, kctx->threshold, &kctx->threshold, NULL));
891: PetscCall(PetscOptionsReal("-ksp_ew_v4_p1", "p1", NULL, kctx->v4_p1, &kctx->v4_p1, NULL));
892: PetscCall(PetscOptionsReal("-ksp_ew_v4_p2", "p2", NULL, kctx->v4_p2, &kctx->v4_p2, NULL));
893: PetscCall(PetscOptionsReal("-ksp_ew_v4_p3", "p3", NULL, kctx->v4_p3, &kctx->v4_p3, NULL));
894: PetscCall(PetscOptionsReal("-ksp_ew_v4_m1", "Scaling when rk-1 in [p2,p3)", NULL, kctx->v4_m1, &kctx->v4_m1, NULL));
895: PetscCall(PetscOptionsReal("-ksp_ew_v4_m2", "Scaling when rk-1 in [p3,+infty)", NULL, kctx->v4_m2, &kctx->v4_m2, NULL));
896: PetscCall(PetscOptionsReal("-ksp_ew_v4_m3", "Threshold for successive rtol (0.1 in Eq.7)", NULL, kctx->v4_m3, &kctx->v4_m3, NULL));
897: PetscCall(PetscOptionsReal("-ksp_ew_v4_m4", "Adaptation scaling (0.5 in Eq.7)", NULL, kctx->v4_m4, &kctx->v4_m4, NULL));
898: PetscOptionsEnd();
899: PetscFunctionReturn(PETSC_SUCCESS);
900: }
902: /*@
903: SNESSetFromOptions - Sets various `SNES` and `KSP` parameters from user options.
905: Collective
907: Input Parameter:
908: . snes - the `SNES` context
910: Options Database Keys:
911: + -snes_type type - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, `SNESType` for complete list
912: . -snes_rtol rtol - relative decrease in tolerance norm from initial
913: . -snes_atol abstol - absolute tolerance of residual norm
914: . -snes_stol stol - convergence tolerance in terms of the norm of the change in the solution between steps
915: . -snes_divergence_tolerance divtol - if the residual goes above divtol*rnorm0, exit with divergence
916: . -snes_max_it max_it - maximum number of iterations
917: . -snes_max_funcs max_funcs - maximum number of function evaluations
918: . -snes_force_iteration force - force `SNESSolve()` to take at least one iteration
919: . -snes_max_fail max_fail - maximum number of line search failures allowed before stopping, default is none
920: . -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
921: . -snes_lag_preconditioner lag - how often preconditioner is rebuilt (use -1 to never rebuild)
922: . -snes_lag_preconditioner_persists (true|false) - retains the -snes_lag_preconditioner information across multiple SNESSolve()
923: . -snes_lag_jacobian lag - how often Jacobian is rebuilt (use -1 to never rebuild)
924: . -snes_lag_jacobian_persists (true|false) - retains the -snes_lag_jacobian information across multiple SNESSolve()
925: . -snes_convergence_test (default|skip|correct_pressure) - convergence test in nonlinear solver. default `SNESConvergedDefault()`. skip `SNESConvergedSkip()` means continue
926: iterating until max_it or some other criterion is reached, saving expense of convergence test. correct_pressure
927: `SNESConvergedCorrectPressure()` has special handling of a pressure null space.
928: . -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
929: . -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
930: . -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
931: . -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
932: . -snes_monitor draw::draw_lg - plots residual norm at each iteration
933: . -snes_monitor_lg_range - plots function range at each iteration
934: . -snes_monitor_pause_final - Pauses all monitor drawing after the solver ends
935: . -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
936: . -snes_fd_color - use finite differences with coloring to compute Jacobian
937: . -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each `KSP` iteration
938: . -snes_converged_reason - print the reason for convergence/divergence after each solve
939: . -npc_snes_type type - the `SNES` type to use as a nonlinear preconditioner
940: . -snes_test_jacobian [threshold] - compare the user provided Jacobian with one computed via finite differences to check for errors.
941: If a threshold is given, display only those entries whose difference is greater than the threshold.
942: - -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference between them
943: to help users detect the location of errors in the user provided Jacobian.
945: Options Database Keys for Eisenstat-Walker method:
946: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
947: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
948: . -snes_ksp_ew_rtol0 rtol0 - Sets rtol0
949: . -snes_ksp_ew_rtolmax rtolmax - Sets rtolmax
950: . -snes_ksp_ew_gamma gamma - Sets gamma
951: . -snes_ksp_ew_alpha alpha - Sets alpha
952: . -snes_ksp_ew_alpha2 alpha2 - Sets alpha2
953: - -snes_ksp_ew_threshold threshold - Sets threshold
955: Level: beginner
957: Notes:
958: To see all options, run your program with the -help option or consult the users manual
960: See `SNESLineSearchSetFromOptions()` for all the line search options available
962: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
963: and computing explicitly with
964: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
966: .seealso: [](ch_snes), `SNESType`, `SNESSetOptionsPrefix()`, `SNESResetFromOptions()`, `SNES`, `SNESCreate()`, `MatCreateSNESMF()`, `MatFDColoring`, `SNESLineSearchSetFromOptions()`
967: @*/
968: PetscErrorCode SNESSetFromOptions(SNES snes)
969: {
970: PetscBool flg, pcset, persist, set;
971: PetscInt i, indx, lag, grids, max_its, max_funcs;
972: const char *deft = SNESNEWTONLS;
973: const char *convtests[] = {"default", "skip", "correct_pressure"};
974: SNESKSPEW *kctx = NULL;
975: char type[256], monfilename[PETSC_MAX_PATH_LEN], ewprefix[256];
976: PCSide pcside;
977: const char *optionsprefix;
978: PetscReal rtol, abstol, stol;
980: PetscFunctionBegin;
982: PetscCall(SNESRegisterAll());
983: PetscObjectOptionsBegin((PetscObject)snes);
984: if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
985: PetscCall(PetscOptionsFList("-snes_type", "Nonlinear solver method", "SNESSetType", SNESList, deft, type, 256, &flg));
986: if (flg) PetscCall(SNESSetType(snes, type));
987: else if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, deft));
989: abstol = snes->abstol;
990: rtol = snes->rtol;
991: stol = snes->stol;
992: max_its = snes->max_its;
993: max_funcs = snes->max_funcs;
994: PetscCall(PetscOptionsReal("-snes_rtol", "Stop if decrease in function norm less than", "SNESSetTolerances", snes->rtol, &rtol, NULL));
995: PetscCall(PetscOptionsReal("-snes_atol", "Stop if function norm less than", "SNESSetTolerances", snes->abstol, &abstol, NULL));
996: PetscCall(PetscOptionsReal("-snes_stol", "Stop if step length less than", "SNESSetTolerances", snes->stol, &stol, NULL));
997: PetscCall(PetscOptionsInt("-snes_max_it", "Maximum iterations", "SNESSetTolerances", snes->max_its, &max_its, NULL));
998: PetscCall(PetscOptionsInt("-snes_max_funcs", "Maximum function evaluations", "SNESSetTolerances", snes->max_funcs, &max_funcs, NULL));
999: PetscCall(SNESSetTolerances(snes, abstol, rtol, stol, max_its, max_funcs));
1001: PetscCall(PetscOptionsReal("-snes_divergence_tolerance", "Stop if residual norm increases by this factor", "SNESSetDivergenceTolerance", snes->divtol, &snes->divtol, &flg));
1002: if (flg) PetscCall(SNESSetDivergenceTolerance(snes, snes->divtol));
1004: PetscCall(PetscOptionsInt("-snes_max_fail", "Maximum nonlinear step failures", "SNESSetMaxNonlinearStepFailures", snes->maxFailures, &snes->maxFailures, &flg));
1005: if (flg) PetscCall(SNESSetMaxNonlinearStepFailures(snes, snes->maxFailures));
1007: PetscCall(PetscOptionsInt("-snes_max_linear_solve_fail", "Maximum failures in linear solves allowed", "SNESSetMaxLinearSolveFailures", snes->maxLinearSolveFailures, &snes->maxLinearSolveFailures, &flg));
1008: if (flg) PetscCall(SNESSetMaxLinearSolveFailures(snes, snes->maxLinearSolveFailures));
1010: PetscCall(PetscOptionsBool("-snes_error_if_not_converged", "Generate error if solver does not converge", "SNESSetErrorIfNotConverged", snes->errorifnotconverged, &snes->errorifnotconverged, NULL));
1011: PetscCall(PetscOptionsBool("-snes_force_iteration", "Force SNESSolve() to take at least one iteration", "SNESSetForceIteration", snes->forceiteration, &snes->forceiteration, NULL));
1012: PetscCall(PetscOptionsBool("-snes_check_jacobian_domain_error", "Check Jacobian domain error after Jacobian evaluation", "SNESCheckJacobianDomainError", snes->checkjacdomainerror, &snes->checkjacdomainerror, NULL));
1014: PetscCall(PetscOptionsInt("-snes_lag_preconditioner", "How often to rebuild preconditioner", "SNESSetLagPreconditioner", snes->lagpreconditioner, &lag, &flg));
1015: if (flg) {
1016: 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");
1017: PetscCall(SNESSetLagPreconditioner(snes, lag));
1018: }
1019: PetscCall(PetscOptionsBool("-snes_lag_preconditioner_persists", "Preconditioner lagging through multiple SNES solves", "SNESSetLagPreconditionerPersists", snes->lagjac_persist, &persist, &flg));
1020: if (flg) PetscCall(SNESSetLagPreconditionerPersists(snes, persist));
1021: PetscCall(PetscOptionsInt("-snes_lag_jacobian", "How often to rebuild Jacobian", "SNESSetLagJacobian", snes->lagjacobian, &lag, &flg));
1022: if (flg) {
1023: 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");
1024: PetscCall(SNESSetLagJacobian(snes, lag));
1025: }
1026: PetscCall(PetscOptionsBool("-snes_lag_jacobian_persists", "Jacobian lagging through multiple SNES solves", "SNESSetLagJacobianPersists", snes->lagjac_persist, &persist, &flg));
1027: if (flg) PetscCall(SNESSetLagJacobianPersists(snes, persist));
1029: PetscCall(PetscOptionsInt("-snes_grid_sequence", "Use grid sequencing to generate initial guess", "SNESSetGridSequence", snes->gridsequence, &grids, &flg));
1030: if (flg) PetscCall(SNESSetGridSequence(snes, grids));
1032: PetscCall(PetscOptionsEList("-snes_convergence_test", "Convergence test", "SNESSetConvergenceTest", convtests, PETSC_STATIC_ARRAY_LENGTH(convtests), "default", &indx, &flg));
1033: if (flg) {
1034: switch (indx) {
1035: case 0:
1036: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedDefault, NULL, NULL));
1037: break;
1038: case 1:
1039: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedSkip, NULL, NULL));
1040: break;
1041: case 2:
1042: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedCorrectPressure, NULL, NULL));
1043: break;
1044: }
1045: }
1047: PetscCall(PetscOptionsEList("-snes_norm_schedule", "SNES Norm schedule", "SNESSetNormSchedule", SNESNormSchedules, 5, "function", &indx, &flg));
1048: if (flg) PetscCall(SNESSetNormSchedule(snes, (SNESNormSchedule)indx));
1050: PetscCall(PetscOptionsEList("-snes_function_type", "SNES Norm schedule", "SNESSetFunctionType", SNESFunctionTypes, 2, "unpreconditioned", &indx, &flg));
1051: if (flg) PetscCall(SNESSetFunctionType(snes, (SNESFunctionType)indx));
1053: kctx = (SNESKSPEW *)snes->kspconvctx;
1055: PetscCall(PetscOptionsBool("-snes_ksp_ew", "Use Eisentat-Walker linear system convergence test", "SNESKSPSetUseEW", snes->ksp_ewconv, &snes->ksp_ewconv, NULL));
1057: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1058: PetscCall(PetscSNPrintf(ewprefix, sizeof(ewprefix), "%s%s", optionsprefix ? optionsprefix : "", "snes_"));
1059: PetscCall(SNESEWSetFromOptions_Private(kctx, PETSC_TRUE, PetscObjectComm((PetscObject)snes), ewprefix));
1061: flg = PETSC_FALSE;
1062: PetscCall(PetscOptionsBool("-snes_monitor_cancel", "Remove all monitors", "SNESMonitorCancel", flg, &flg, &set));
1063: if (set && flg) PetscCall(SNESMonitorCancel(snes));
1065: PetscCall(PetscOptionsDeprecated("-snes_monitor_short", "-snes_monitor", "3.26", NULL));
1066: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor", "Monitor norm of function", "SNESMonitorDefault", SNESMonitorDefault, SNESMonitorDefaultSetUp));
1067: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_range", "Monitor range of elements of function", "SNESMonitorRange", SNESMonitorRange, NULL));
1069: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_ratio", "Monitor ratios of the norm of function for consecutive steps", "SNESMonitorRatio", SNESMonitorRatio, SNESMonitorRatioSetUp));
1070: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_field", "Monitor norm of function (split into fields)", "SNESMonitorDefaultField", SNESMonitorDefaultField, NULL));
1071: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution", "View solution at each iteration", "SNESMonitorSolution", SNESMonitorSolution, NULL));
1072: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution_update", "View correction at each iteration", "SNESMonitorSolutionUpdate", SNESMonitorSolutionUpdate, NULL));
1073: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_residual", "View residual at each iteration", "SNESMonitorResidual", SNESMonitorResidual, NULL));
1074: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_jacupdate_spectrum", "Print the change in the spectrum of the Jacobian", "SNESMonitorJacUpdateSpectrum", SNESMonitorJacUpdateSpectrum, NULL));
1075: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_fields", "Monitor norm of function per field", "SNESMonitorSet", SNESMonitorFields, NULL));
1076: PetscCall(PetscOptionsBool("-snes_monitor_pause_final", "Pauses all draw monitors at the final iterate", "SNESMonitorPauseFinal_Internal", PETSC_FALSE, &snes->pauseFinal, NULL));
1078: PetscCall(PetscOptionsString("-snes_monitor_python", "Use Python function", "SNESMonitorSet", NULL, monfilename, sizeof(monfilename), &flg));
1079: if (flg) PetscCall(PetscPythonMonitorSet((PetscObject)snes, monfilename));
1081: flg = PETSC_FALSE;
1082: PetscCall(PetscOptionsBool("-snes_monitor_lg_range", "Plot function range at each iteration", "SNESMonitorLGRange", flg, &flg, NULL));
1083: if (flg) {
1084: PetscViewer ctx;
1086: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, NULL, PETSC_DECIDE, PETSC_DECIDE, 400, 300, &ctx));
1087: PetscCall(SNESMonitorSet(snes, SNESMonitorLGRange, ctx, (PetscCtxDestroyFn *)PetscViewerDestroy));
1088: }
1090: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
1091: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_converged_reason", &snes->convergedreasonviewer, &snes->convergedreasonformat, NULL));
1092: flg = PETSC_FALSE;
1093: PetscCall(PetscOptionsBool("-snes_converged_reason_view_cancel", "Remove all converged reason viewers", "SNESConvergedReasonViewCancel", flg, &flg, &set));
1094: if (set && flg) PetscCall(SNESConvergedReasonViewCancel(snes));
1096: flg = PETSC_FALSE;
1097: PetscCall(PetscOptionsBool("-snes_fd", "Use finite differences (slow) to compute Jacobian", "SNESComputeJacobianDefault", flg, &flg, NULL));
1098: if (flg) {
1099: void *functx;
1100: DM dm;
1101: PetscCall(SNESGetDM(snes, &dm));
1102: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1103: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
1104: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefault, functx));
1105: PetscCall(PetscInfo(snes, "Setting default finite difference Jacobian matrix\n"));
1106: }
1108: flg = PETSC_FALSE;
1109: PetscCall(PetscOptionsBool("-snes_fd_function", "Use finite differences (slow) to compute function from user objective", "SNESObjectiveComputeFunctionDefaultFD", flg, &flg, NULL));
1110: if (flg) PetscCall(SNESSetFunction(snes, NULL, SNESObjectiveComputeFunctionDefaultFD, NULL));
1112: flg = PETSC_FALSE;
1113: PetscCall(PetscOptionsBool("-snes_fd_color", "Use finite differences with coloring to compute Jacobian", "SNESComputeJacobianDefaultColor", flg, &flg, NULL));
1114: if (flg) {
1115: DM dm;
1116: PetscCall(SNESGetDM(snes, &dm));
1117: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1118: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefaultColor, NULL));
1119: PetscCall(PetscInfo(snes, "Setting default finite difference coloring Jacobian matrix\n"));
1120: }
1122: flg = PETSC_FALSE;
1123: 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));
1124: if (flg && snes->mf_operator) {
1125: snes->mf_operator = PETSC_TRUE;
1126: snes->mf = PETSC_TRUE;
1127: }
1128: flg = PETSC_FALSE;
1129: PetscCall(PetscOptionsBool("-snes_mf", "Use a Matrix-Free Jacobian with no preconditioner by default", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf, &flg));
1130: if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1131: PetscCall(PetscOptionsInt("-snes_mf_version", "Matrix-Free routines version 1 or 2", "None", snes->mf_version, &snes->mf_version, NULL));
1133: PetscCall(PetscOptionsName("-snes_test_function", "Compare hand-coded and finite difference functions", "None", &snes->testFunc));
1134: PetscCall(PetscOptionsName("-snes_test_jacobian", "Compare hand-coded and finite difference Jacobians", "None", &snes->testJac));
1136: flg = PETSC_FALSE;
1137: PetscCall(SNESGetNPCSide(snes, &pcside));
1138: PetscCall(PetscOptionsEnum("-snes_npc_side", "SNES nonlinear preconditioner side", "SNESSetNPCSide", PCSides, (PetscEnum)pcside, (PetscEnum *)&pcside, &flg));
1139: if (flg) PetscCall(SNESSetNPCSide(snes, pcside));
1141: #if PetscDefined(HAVE_SAWS)
1142: /*
1143: Publish convergence information using SAWs
1144: */
1145: flg = PETSC_FALSE;
1146: PetscCall(PetscOptionsBool("-snes_monitor_saws", "Publish SNES progress using SAWs", "SNESMonitorSet", flg, &flg, NULL));
1147: if (flg) {
1148: PetscCtx ctx;
1149: PetscCall(SNESMonitorSAWsCreate(snes, &ctx));
1150: PetscCall(SNESMonitorSet(snes, SNESMonitorSAWs, ctx, SNESMonitorSAWsDestroy));
1151: }
1152: #endif
1153: #if PetscDefined(HAVE_SAWS)
1154: {
1155: PetscBool set;
1156: flg = PETSC_FALSE;
1157: PetscCall(PetscOptionsBool("-snes_saws_block", "Block for SAWs at end of SNESSolve", "PetscObjectSAWsBlock", ((PetscObject)snes)->amspublishblock, &flg, &set));
1158: if (set) PetscCall(PetscObjectSAWsSetBlock((PetscObject)snes, flg));
1159: }
1160: #endif
1162: for (i = 0; i < numberofsetfromoptions; i++) PetscCall((*othersetfromoptions[i])(snes));
1164: PetscTryTypeMethod(snes, setfromoptions, PetscOptionsObject);
1166: /* process any options handlers added with PetscObjectAddOptionsHandler() */
1167: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)snes, PetscOptionsObject));
1168: PetscOptionsEnd();
1170: if (snes->linesearch) {
1171: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
1172: PetscCall(SNESLineSearchSetFromOptions(snes->linesearch));
1173: }
1175: /* if user has set the SNES NPC type via options database, create it. */
1176: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1177: PetscCall(PetscOptionsHasName(((PetscObject)snes)->options, optionsprefix, "-npc_snes_type", &pcset));
1178: if (pcset && !snes->npc) PetscCall(SNESGetNPC(snes, &snes->npc));
1180: if (snes->usesksp) {
1181: PC pc;
1182: PCType pctype;
1184: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
1185: PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre));
1186: PetscCall(KSPGetPC(snes->ksp, &pc));
1187: PetscCall(PCGetType(pc, &pctype));
1188: /* If the first two conditions in the following conditional are true, we know a matrix-free Mat
1189: will be used eventually with the PC, but we cannot provide the matrix-free Mat to the PC here
1190: since we do not have enough information to construct it here (it is constructed after the
1191: start of SNESSetUp()). If we do not set the PCNONE here, then the PCSetFromOptions() called
1192: from KSPSetFromOptions() below will use PCGetDefaultType_Private() to set a PCType
1193: appropriate for the current pc->pmat that will likely not work for the matrix-free Mat, thus
1194: producing a later confusing error message. A significant refactoring of how SNES handles
1195: matrix-free Mat would be needed to eliminate the next line of code. Note that if the PC type
1196: has already been set (third condition), we do not override it. The fourth condition exempts
1197: left-side nonlinear preconditioners, which require a real PC */
1198: if (snes->mf && !snes->mf_operator && !pctype && !(snes->npcside == PC_LEFT && snes->npc)) {
1199: PetscCall(PetscInfo(snes, "Setting PCNONE since no PC type was set and the Jacobian will be matrix-free\n"));
1200: PetscCall(PCSetType(pc, PCNONE));
1201: }
1202: PetscCall(KSPSetFromOptions(snes->ksp));
1203: }
1205: if (snes->npc) PetscCall(SNESSetFromOptions(snes->npc));
1206: snes->setfromoptionscalled++;
1207: PetscFunctionReturn(PETSC_SUCCESS);
1208: }
1210: /*@
1211: SNESResetFromOptions - Sets various `SNES` and `KSP` parameters from user options ONLY if the `SNESSetFromOptions()` was previously called
1213: Collective
1215: Input Parameter:
1216: . snes - the `SNES` context
1218: Level: advanced
1220: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESSetOptionsPrefix()`
1221: @*/
1222: PetscErrorCode SNESResetFromOptions(SNES snes)
1223: {
1224: PetscFunctionBegin;
1225: if (snes->setfromoptionscalled) PetscCall(SNESSetFromOptions(snes));
1226: PetscFunctionReturn(PETSC_SUCCESS);
1227: }
1229: /*@
1230: SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1231: the nonlinear solvers.
1233: Logically Collective; No Fortran Support
1235: Input Parameters:
1236: + snes - the `SNES` context
1237: . compute - function to compute the context
1238: - destroy - function to destroy the context, see `PetscCtxDestroyFn` for the calling sequence
1240: Calling sequence of `compute`:
1241: + snes - the `SNES` context
1242: - ctx - context to be computed
1244: Level: intermediate
1246: Note:
1247: This routine is useful if you are performing grid sequencing or using `SNESFAS` and need the appropriate context generated for each level.
1249: Use `SNESSetApplicationContext()` to see the context immediately
1251: .seealso: [](ch_snes), `SNESGetApplicationContext()`, `SNESSetApplicationContext()`, `PetscCtxDestroyFn`
1252: @*/
1253: PetscErrorCode SNESSetComputeApplicationContext(SNES snes, PetscErrorCode (*compute)(SNES snes, PetscCtxRt ctx), PetscCtxDestroyFn *destroy)
1254: {
1255: PetscFunctionBegin;
1257: snes->ops->ctxcompute = compute;
1258: snes->ops->ctxdestroy = destroy;
1259: PetscFunctionReturn(PETSC_SUCCESS);
1260: }
1262: /*@
1263: SNESSetApplicationContext - Sets the optional user-defined context for the nonlinear solvers.
1265: Logically Collective
1267: Input Parameters:
1268: + snes - the `SNES` context
1269: - ctx - the application context
1271: Level: intermediate
1273: Notes:
1274: Users can provide a context when constructing the `SNES` options and then access it inside their function, Jacobian computation, or other evaluation function
1275: with `SNESGetApplicationContext()`
1277: To provide a function that computes the context for you use `SNESSetComputeApplicationContext()`
1279: Fortran Note:
1280: This only works when `ctx` is a Fortran derived type (it cannot be a `PetscObject`), we recommend writing a Fortran interface definition for this
1281: function that tells the Fortran compiler the derived data type that is passed in as the `ctx` argument. See `SNESGetApplicationContext()` for
1282: an example.
1284: .seealso: [](ch_snes), `SNES`, `SNESSetComputeApplicationContext()`, `SNESGetApplicationContext()`
1285: @*/
1286: PetscErrorCode SNESSetApplicationContext(SNES snes, PetscCtx ctx)
1287: {
1288: KSP ksp;
1290: PetscFunctionBegin;
1292: PetscCall(SNESGetKSP(snes, &ksp));
1293: PetscCall(KSPSetApplicationContext(ksp, ctx));
1294: snes->ctx = ctx;
1295: PetscFunctionReturn(PETSC_SUCCESS);
1296: }
1298: /*@
1299: SNESGetApplicationContext - Gets the user-defined context for the
1300: nonlinear solvers set with `SNESGetApplicationContext()` or `SNESSetComputeApplicationContext()`
1302: Not Collective
1304: Input Parameter:
1305: . snes - `SNES` context
1307: Output Parameter:
1308: . ctx - the application context
1310: Level: intermediate
1312: Fortran Notes:
1313: This only works when the context is a Fortran derived type or a `PetscObject`. Declare `ctx` with
1314: .vb
1315: type(tUsertype), pointer :: ctx
1316: .ve
1318: .seealso: [](ch_snes), `SNESSetApplicationContext()`, `SNESSetComputeApplicationContext()`
1319: @*/
1320: PetscErrorCode SNESGetApplicationContext(SNES snes, PetscCtxRt ctx)
1321: {
1322: PetscFunctionBegin;
1324: *(void **)ctx = snes->ctx;
1325: PetscFunctionReturn(PETSC_SUCCESS);
1326: }
1328: /*@
1329: SNESSetUseMatrixFree - indicates that `SNES` should use matrix-free finite difference matrix-vector products to apply the Jacobian.
1331: Logically Collective
1333: Input Parameters:
1334: + snes - `SNES` context
1335: . mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1336: - 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
1337: this option no matrix-element based preconditioners can be used in the linear solve since the matrix won't be explicitly available
1339: Options Database Keys:
1340: + -snes_mf_operator - use matrix-free only for the mat operator
1341: . -snes_mf - use matrix-free for both the mat and pmat operator
1342: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1343: - -snes_fd - compute the Jacobian via finite differences (slow)
1345: Level: intermediate
1347: Notes:
1348: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
1349: and computing explicitly with
1350: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
1352: When `mf` is used, `SNESSetFromOptions()` sets the `KSP`'s `PC` to `PCNONE` unless a `PC` type has already been selected.
1354: .seealso: [](ch_snes), `SNES`, `SNESGetUseMatrixFree()`, `MatCreateSNESMF()`, `SNESComputeJacobianDefaultColor()`, `MatFDColoring`
1355: @*/
1356: PetscErrorCode SNESSetUseMatrixFree(SNES snes, PetscBool mf_operator, PetscBool mf)
1357: {
1358: PetscFunctionBegin;
1362: snes->mf = mf_operator ? PETSC_TRUE : mf;
1363: snes->mf_operator = mf_operator;
1364: PetscFunctionReturn(PETSC_SUCCESS);
1365: }
1367: /*@
1368: SNESGetUseMatrixFree - indicates if the `SNES` uses matrix-free finite difference matrix vector products to apply the Jacobian.
1370: Not Collective, but the resulting flags will be the same on all MPI processes
1372: Input Parameter:
1373: . snes - `SNES` context
1375: Output Parameters:
1376: + mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1377: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored
1379: Level: intermediate
1381: .seealso: [](ch_snes), `SNES`, `SNESSetUseMatrixFree()`, `MatCreateSNESMF()`
1382: @*/
1383: PetscErrorCode SNESGetUseMatrixFree(SNES snes, PetscBool *mf_operator, PetscBool *mf)
1384: {
1385: PetscFunctionBegin;
1387: if (mf) *mf = snes->mf;
1388: if (mf_operator) *mf_operator = snes->mf_operator;
1389: PetscFunctionReturn(PETSC_SUCCESS);
1390: }
1392: /*@
1393: SNESGetIterationNumber - Gets the number of nonlinear iterations completed in the current or most recent `SNESSolve()`
1395: Not Collective
1397: Input Parameter:
1398: . snes - `SNES` context
1400: Output Parameter:
1401: . iter - iteration number
1403: Level: intermediate
1405: Notes:
1406: For example, during the computation of iteration 2 this would return 1.
1408: This is useful for using lagged Jacobians (where one does not recompute the
1409: Jacobian at each `SNES` iteration). For example, the code
1410: .vb
1411: ierr = SNESGetIterationNumber(snes,&it);
1412: if (!(it % 2)) {
1413: [compute Jacobian here]
1414: }
1415: .ve
1416: can be used in your function that computes the Jacobian to cause the Jacobian to be
1417: recomputed every second `SNES` iteration. See also `SNESSetLagJacobian()`
1419: After the `SNES` solve is complete this will return the number of nonlinear iterations used.
1421: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetLagJacobian()`, `SNESGetLinearSolveIterations()`, `SNESSetMonitor()`
1422: @*/
1423: PetscErrorCode SNESGetIterationNumber(SNES snes, PetscInt *iter)
1424: {
1425: PetscFunctionBegin;
1427: PetscAssertPointer(iter, 2);
1428: *iter = snes->iter;
1429: PetscFunctionReturn(PETSC_SUCCESS);
1430: }
1432: /*@
1433: SNESSetIterationNumber - Sets the current iteration number.
1435: Not Collective
1437: Input Parameters:
1438: + snes - `SNES` context
1439: - iter - iteration number
1441: Level: developer
1443: Note:
1444: This should only be called inside a `SNES` nonlinear solver.
1446: .seealso: [](ch_snes), `SNESGetLinearSolveIterations()`
1447: @*/
1448: PetscErrorCode SNESSetIterationNumber(SNES snes, PetscInt iter)
1449: {
1450: PetscFunctionBegin;
1452: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
1453: snes->iter = iter;
1454: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
1455: PetscFunctionReturn(PETSC_SUCCESS);
1456: }
1458: /*@
1459: SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1460: taken by the nonlinear solver in the current or most recent `SNESSolve()` .
1462: Not Collective
1464: Input Parameter:
1465: . snes - `SNES` context
1467: Output Parameter:
1468: . nfails - number of unsuccessful steps attempted
1470: Level: intermediate
1472: Notes:
1473: A failed step is a step that was generated and taken but did not satisfy the requested step criteria. For example,
1474: the `SNESLineSearchApply()` could not generate a sufficient decrease in the function norm (in fact it may have produced an increase).
1476: Taken steps that produce a infinity or NaN in the function evaluation or generate a `SNESSetFunctionDomainError()`
1477: will always immediately terminate the `SNESSolve()` regardless of the value of `maxFails`.
1479: `SNESSetMaxNonlinearStepFailures()` determines how many unsuccessful steps are allowed before the `SNESSolve()` terminates
1481: This counter is reset to zero for each successive call to `SNESSolve()`.
1483: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1484: `SNESSetMaxNonlinearStepFailures()`, `SNESGetMaxNonlinearStepFailures()`
1485: @*/
1486: PetscErrorCode SNESGetNonlinearStepFailures(SNES snes, PetscInt *nfails)
1487: {
1488: PetscFunctionBegin;
1490: PetscAssertPointer(nfails, 2);
1491: *nfails = snes->numFailures;
1492: PetscFunctionReturn(PETSC_SUCCESS);
1493: }
1495: /*@
1496: SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1497: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1499: Not Collective
1501: Input Parameters:
1502: + snes - `SNES` context
1503: - maxFails - maximum of unsuccessful steps allowed, use `PETSC_UNLIMITED` to have no limit on the number of failures
1505: Options Database Key:
1506: . -snes_max_fail n - maximum number of unsuccessful steps allowed
1508: Level: intermediate
1510: Note:
1511: A failed step is a step that was generated and taken but did not satisfy the requested criteria. For example,
1512: the `SNESLineSearchApply()` could not generate a sufficient decrease in the function norm (in fact it may have produced an increase).
1514: Taken steps that produce a infinity or NaN in the function evaluation or generate a `SNESSetFunctionDomainError()`
1515: will always immediately terminate the `SNESSolve()` regardless of the value of `maxFails`.
1517: Developer Note:
1518: The options database key is wrong for this function name
1520: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`,
1521: `SNESGetLinearSolveFailures()`, `SNESGetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`, `SNESCheckLineSearchFailure()`
1522: @*/
1523: PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1524: {
1525: PetscFunctionBegin;
1528: if (maxFails == PETSC_UNLIMITED) {
1529: snes->maxFailures = PETSC_INT_MAX;
1530: } else {
1531: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1532: snes->maxFailures = maxFails;
1533: }
1534: PetscFunctionReturn(PETSC_SUCCESS);
1535: }
1537: /*@
1538: SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1539: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1541: Not Collective
1543: Input Parameter:
1544: . snes - `SNES` context
1546: Output Parameter:
1547: . maxFails - maximum of unsuccessful steps
1549: Level: intermediate
1551: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1552: `SNESSetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1553: @*/
1554: PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1555: {
1556: PetscFunctionBegin;
1558: PetscAssertPointer(maxFails, 2);
1559: *maxFails = snes->maxFailures;
1560: PetscFunctionReturn(PETSC_SUCCESS);
1561: }
1563: /*@
1564: SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1565: done by the `SNES` object in the current or most recent `SNESSolve()`
1567: Not Collective
1569: Input Parameter:
1570: . snes - `SNES` context
1572: Output Parameter:
1573: . nfuncs - number of evaluations
1575: Level: intermediate
1577: Note:
1578: Reset every time `SNESSolve()` is called unless `SNESSetCountersReset()` is used.
1580: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`, `SNESSetCountersReset()`
1581: @*/
1582: PetscErrorCode SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1583: {
1584: PetscFunctionBegin;
1586: PetscAssertPointer(nfuncs, 2);
1587: *nfuncs = snes->nfuncs;
1588: PetscFunctionReturn(PETSC_SUCCESS);
1589: }
1591: /*@
1592: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1593: linear solvers in the current or most recent `SNESSolve()`
1595: Not Collective
1597: Input Parameter:
1598: . snes - `SNES` context
1600: Output Parameter:
1601: . nfails - number of failed solves
1603: Options Database Key:
1604: . -snes_max_linear_solve_fail num - The number of failures before the solve is terminated
1606: Level: intermediate
1608: Note:
1609: This counter is reset to zero for each successive call to `SNESSolve()`.
1611: .seealso: [](ch_snes), `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1612: @*/
1613: PetscErrorCode SNESGetLinearSolveFailures(SNES snes, PetscInt *nfails)
1614: {
1615: PetscFunctionBegin;
1617: PetscAssertPointer(nfails, 2);
1618: *nfails = snes->numLinearSolveFailures;
1619: PetscFunctionReturn(PETSC_SUCCESS);
1620: }
1622: /*@
1623: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1624: allowed before `SNES` returns with a diverged reason of `SNES_DIVERGED_LINEAR_SOLVE`
1626: Logically Collective
1628: Input Parameters:
1629: + snes - `SNES` context
1630: - maxFails - maximum allowed linear solve failures, use `PETSC_UNLIMITED` to have no limit on the number of failures
1632: Options Database Key:
1633: . -snes_max_linear_solve_fail num - The number of failures before the solve is terminated
1635: Level: intermediate
1637: Note:
1638: By default this is 0; that is `SNES` returns on the first failed linear solve
1640: Developer Note:
1641: The options database key is wrong for this function name
1643: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`
1644: @*/
1645: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1646: {
1647: PetscFunctionBegin;
1651: if (maxFails == PETSC_UNLIMITED) {
1652: snes->maxLinearSolveFailures = PETSC_INT_MAX;
1653: } else {
1654: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1655: snes->maxLinearSolveFailures = maxFails;
1656: }
1657: PetscFunctionReturn(PETSC_SUCCESS);
1658: }
1660: /*@
1661: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1662: are allowed before `SNES` returns as unsuccessful
1664: Not Collective
1666: Input Parameter:
1667: . snes - `SNES` context
1669: Output Parameter:
1670: . maxFails - maximum of unsuccessful solves allowed
1672: Level: intermediate
1674: Note:
1675: By default this is 1; that is `SNES` returns on the first failed linear solve
1677: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1678: @*/
1679: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1680: {
1681: PetscFunctionBegin;
1683: PetscAssertPointer(maxFails, 2);
1684: *maxFails = snes->maxLinearSolveFailures;
1685: PetscFunctionReturn(PETSC_SUCCESS);
1686: }
1688: /*@
1689: SNESGetLinearSolveIterations - Gets the total number of linear iterations
1690: used by the nonlinear solver in the most recent `SNESSolve()`
1692: Not Collective
1694: Input Parameter:
1695: . snes - `SNES` context
1697: Output Parameter:
1698: . lits - number of linear iterations
1700: Level: intermediate
1702: Notes:
1703: This counter is reset to zero for each successive call to `SNESSolve()` unless `SNESSetCountersReset()` is used.
1705: 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
1706: then call `KSPGetIterationNumber()` after the failed solve.
1708: .seealso: [](ch_snes), `SNES`, `SNESGetIterationNumber()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESSetCountersReset()`
1709: @*/
1710: PetscErrorCode SNESGetLinearSolveIterations(SNES snes, PetscInt *lits)
1711: {
1712: PetscFunctionBegin;
1714: PetscAssertPointer(lits, 2);
1715: *lits = snes->linear_its;
1716: PetscFunctionReturn(PETSC_SUCCESS);
1717: }
1719: /*@
1720: SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1721: are reset every time `SNESSolve()` is called.
1723: Logically Collective
1725: Input Parameters:
1726: + snes - `SNES` context
1727: - reset - whether to reset the counters or not, defaults to `PETSC_TRUE`
1729: Level: developer
1731: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1732: @*/
1733: PetscErrorCode SNESSetCountersReset(SNES snes, PetscBool reset)
1734: {
1735: PetscFunctionBegin;
1738: snes->counters_reset = reset;
1739: PetscFunctionReturn(PETSC_SUCCESS);
1740: }
1742: /*@
1743: SNESResetCounters - Reset counters for linear iterations and function evaluations.
1745: Logically Collective
1747: Input Parameters:
1748: . snes - `SNES` context
1750: Level: developer
1752: Note:
1753: It honors the flag set with `SNESSetCountersReset()`
1755: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1756: @*/
1757: PetscErrorCode SNESResetCounters(SNES snes)
1758: {
1759: PetscFunctionBegin;
1761: if (snes->counters_reset) {
1762: snes->nfuncs = 0;
1763: snes->linear_its = 0;
1764: snes->numFailures = 0;
1765: }
1766: PetscFunctionReturn(PETSC_SUCCESS);
1767: }
1769: /*@
1770: SNESSetKSP - Sets a `KSP` context for the `SNES` object to use
1772: Not Collective, but the `SNES` and `KSP` objects must live on the same `MPI_Comm`
1774: Input Parameters:
1775: + snes - the `SNES` context
1776: - ksp - the `KSP` context
1778: Level: developer
1780: Notes:
1781: The `SNES` object already has its `KSP` object, you can obtain with `SNESGetKSP()`
1782: so this routine is rarely needed.
1784: The `KSP` object that is already in the `SNES` object has its reference count
1785: decreased by one when this is called.
1787: .seealso: [](ch_snes), `SNES`, `KSP`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`
1788: @*/
1789: PetscErrorCode SNESSetKSP(SNES snes, KSP ksp)
1790: {
1791: PetscFunctionBegin;
1794: PetscCheckSameComm(snes, 1, ksp, 2);
1795: PetscCall(PetscObjectReference((PetscObject)ksp));
1796: PetscCall(PetscObjectDereference((PetscObject)snes->ksp));
1797: snes->ksp = ksp;
1798: PetscFunctionReturn(PETSC_SUCCESS);
1799: }
1801: /*@
1802: SNESParametersInitialize - Sets the base defaults for parameters in `snes`, updating a parameter's current value when it matches its previously recorded default.
1804: Logically collective
1806: Input Parameter:
1807: . snes - the `SNES` object
1809: Level: developer
1811: Notes:
1813: The base defaults are the non-type-specific values established when the `SNES` is created. A `SNESType` constructor may subsequently replace them with type-specific defaults.
1815: Developer Notes:
1817: `SNESCreate()` calls this routine to establish the base defaults. `SNESSetType()` calls it before constructing a new `SNESType`, so the recorded defaults associated with the previous type are replaced before the new type installs its own defaults.
1819: Default tracking is based on value equality, not on whether a setter was called. Consequently, an explicitly assigned value that equals the recorded default may be updated when the type changes.
1821: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`,
1822: `PetscObjectParameterSetDefault()`
1823: @*/
1824: PetscErrorCode SNESParametersInitialize(SNES snes)
1825: {
1826: PetscObjectParameterSetDefault(snes, max_its, 50);
1827: PetscObjectParameterSetDefault(snes, max_funcs, 10000);
1828: PetscObjectParameterSetDefault(snes, rtol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1829: PetscObjectParameterSetDefault(snes, abstol, PetscDefined(USE_REAL_SINGLE) ? 1.e-25 : 1.e-50);
1830: PetscObjectParameterSetDefault(snes, stol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1831: PetscObjectParameterSetDefault(snes, divtol, 1.e4);
1832: return PETSC_SUCCESS;
1833: }
1835: /*@
1836: SNESCreate - Creates a nonlinear solver context used to manage a set of nonlinear solves
1838: Collective
1840: Input Parameter:
1841: . comm - MPI communicator
1843: Output Parameter:
1844: . outsnes - the new `SNES` context
1846: Options Database Keys:
1847: + -snes_mf - Activates default matrix-free Jacobian-vector products, with no preconditioner by default
1848: . -snes_mf_operator - Activates default matrix-free Jacobian-vector products, and a user-provided matrix as set by `SNESSetJacobian()`
1849: . -snes_fd_coloring - uses a relative fast computation of the Jacobian using finite differences and a graph coloring
1850: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
1852: Level: beginner
1854: Developer Notes:
1855: `SNES` always creates a `KSP` object even though many `SNES` methods do not use it. This is
1856: unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1857: particular method does use `KSP` and regulates if the information about the `KSP` is printed
1858: in `SNESView()`.
1860: `TSSetFromOptions()` does call `SNESSetFromOptions()` which can lead to users being confused
1861: by help messages about meaningless `SNES` options.
1863: `SNES` always creates the `snes->kspconvctx` even though it is used by only one type. This should be fixed.
1865: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
1866: @*/
1867: PetscErrorCode SNESCreate(MPI_Comm comm, SNES *outsnes)
1868: {
1869: SNES snes;
1870: SNESKSPEW *kctx;
1872: PetscFunctionBegin;
1873: PetscAssertPointer(outsnes, 2);
1874: PetscCall(SNESInitializePackage());
1876: PetscCall(PetscHeaderCreate(snes, SNES_CLASSID, "SNES", "Nonlinear solver", "SNES", comm, SNESDestroy, SNESView));
1877: snes->ops->converged = SNESConvergedDefault;
1878: snes->usesksp = PETSC_TRUE;
1879: snes->norm = 0.0;
1880: snes->xnorm = 0.0;
1881: snes->ynorm = 0.0;
1882: snes->normschedule = SNES_NORM_ALWAYS;
1883: snes->functype = SNES_FUNCTION_DEFAULT;
1884: snes->ttol = 0.0;
1886: snes->rnorm0 = 0;
1887: snes->nfuncs = 0;
1888: snes->numFailures = 0;
1889: snes->maxFailures = 1;
1890: snes->linear_its = 0;
1891: snes->lagjacobian = 1;
1892: snes->jac_iter = 0;
1893: snes->lagjac_persist = PETSC_FALSE;
1894: snes->lagpreconditioner = 1;
1895: snes->pre_iter = 0;
1896: snes->lagpre_persist = PETSC_FALSE;
1897: snes->numbermonitors = 0;
1898: snes->numberreasonviews = 0;
1899: snes->data = NULL;
1900: snes->setupcalled = PETSC_FALSE;
1901: snes->ksp_ewconv = PETSC_FALSE;
1902: snes->nwork = 0;
1903: snes->work = NULL;
1904: snes->nvwork = 0;
1905: snes->vwork = NULL;
1906: snes->conv_hist_len = 0;
1907: snes->conv_hist_max = 0;
1908: snes->conv_hist = NULL;
1909: snes->conv_hist_its = NULL;
1910: snes->conv_hist_reset = PETSC_TRUE;
1911: snes->counters_reset = PETSC_TRUE;
1912: snes->vec_func_init_set = PETSC_FALSE;
1913: snes->reason = SNES_CONVERGED_ITERATING;
1914: snes->npcside = PC_RIGHT;
1915: snes->setfromoptionscalled = 0;
1917: snes->mf = PETSC_FALSE;
1918: snes->mf_operator = PETSC_FALSE;
1919: snes->mf_version = 1;
1921: snes->numLinearSolveFailures = 0;
1922: snes->maxLinearSolveFailures = 1;
1924: snes->vizerotolerance = 1.e-8;
1925: snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;
1927: /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1928: snes->alwayscomputesfinalresidual = PETSC_FALSE;
1930: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1931: PetscCall(PetscNew(&kctx));
1933: snes->kspconvctx = kctx;
1934: kctx->version = 2;
1935: kctx->rtol_0 = 0.3; /* Eisenstat and Walker suggest rtol_0=.5, but
1936: this was too large for some test cases */
1937: kctx->rtol_last = 0.0;
1938: kctx->rtol_max = 0.9;
1939: kctx->gamma = 1.0;
1940: kctx->alpha = 0.5 * (1.0 + PetscSqrtReal(5.0));
1941: kctx->alpha2 = kctx->alpha;
1942: kctx->threshold = 0.1;
1943: kctx->lresid_last = 0.0;
1944: kctx->norm_last = 0.0;
1946: kctx->rk_last = 0.0;
1947: kctx->rk_last_2 = 0.0;
1948: kctx->rtol_last_2 = 0.0;
1949: kctx->v4_p1 = 0.1;
1950: kctx->v4_p2 = 0.4;
1951: kctx->v4_p3 = 0.7;
1952: kctx->v4_m1 = 0.8;
1953: kctx->v4_m2 = 0.5;
1954: kctx->v4_m3 = 0.1;
1955: kctx->v4_m4 = 0.5;
1957: PetscCall(SNESParametersInitialize(snes));
1958: *outsnes = snes;
1959: PetscFunctionReturn(PETSC_SUCCESS);
1960: }
1962: /*@
1963: SNESSetFunction - Sets the function evaluation routine and function
1964: vector for use by the `SNES` routines in solving systems of nonlinear
1965: equations.
1967: Logically Collective
1969: Input Parameters:
1970: + snes - the `SNES` context
1971: . r - vector to store function values, may be `NULL`
1972: . f - function evaluation routine; for calling sequence see `SNESFunctionFn`
1973: - ctx - [optional] user-defined context for private data for the
1974: function evaluation routine (may be `NULL`)
1976: Level: beginner
1978: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetPicard()`, `SNESFunctionFn`
1979: @*/
1980: PetscErrorCode SNESSetFunction(SNES snes, Vec r, SNESFunctionFn *f, PetscCtx ctx)
1981: {
1982: DM dm;
1984: PetscFunctionBegin;
1986: if (r) {
1988: PetscCheckSameComm(snes, 1, r, 2);
1989: PetscCall(PetscObjectReference((PetscObject)r));
1990: PetscCall(VecDestroy(&snes->vec_func));
1991: snes->vec_func = r;
1992: }
1993: /* update DMSNES
1994: We support incremental information; so update the function context only if r is not specified
1995: (which allows to disable the callbacks when both f and ctx are NULL),
1996: or, if r is specified, when at least one of f and ctx is not NULL */
1997: PetscCall(SNESGetDM(snes, &dm));
1998: if (!r || f || ctx) PetscCall(DMSNESSetFunction(dm, f, ctx));
1999: if (f == SNESPicardComputeFunction) PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2000: PetscFunctionReturn(PETSC_SUCCESS);
2001: }
2003: /*@
2004: SNESSetInitialFunction - Set an already computed function evaluation at the initial guess to be reused by `SNESSolve()`.
2006: Logically Collective
2008: Input Parameters:
2009: + snes - the `SNES` context
2010: - f - vector to store function value
2012: Level: developer
2014: Notes:
2015: This should not be modified during the solution procedure.
2017: This is used extensively in the `SNESFAS` hierarchy and in nonlinear preconditioning.
2019: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetInitialFunctionNorm()`
2020: @*/
2021: PetscErrorCode SNESSetInitialFunction(SNES snes, Vec f)
2022: {
2023: Vec vec_func;
2025: PetscFunctionBegin;
2028: PetscCheckSameComm(snes, 1, f, 2);
2029: if (snes->npcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
2030: snes->vec_func_init_set = PETSC_FALSE;
2031: PetscFunctionReturn(PETSC_SUCCESS);
2032: }
2033: PetscCall(SNESGetFunction(snes, &vec_func, NULL, NULL));
2034: PetscCall(VecCopy(f, vec_func));
2036: snes->vec_func_init_set = PETSC_TRUE;
2037: PetscFunctionReturn(PETSC_SUCCESS);
2038: }
2040: /*@
2041: SNESSetNormSchedule - Sets the `SNESNormSchedule` used in convergence and monitoring
2042: of the `SNES` method, when norms are computed in the solving process
2044: Logically Collective
2046: Input Parameters:
2047: + snes - the `SNES` context
2048: - normschedule - the frequency of norm computation
2050: Options Database Key:
2051: . -snes_norm_schedule (none|always|initialonly|finalonly|initialfinalonly) - set the schedule
2053: Level: advanced
2055: Notes:
2056: Only certain `SNES` methods support certain `SNESNormSchedules`. Most require evaluation
2057: of the nonlinear function and the taking of its norm at every iteration to
2058: even ensure convergence at all. However, methods such as custom Gauss-Seidel methods
2059: `SNESNGS` and the like do not require the norm of the function to be computed, and therefore
2060: may either be monitored for convergence or not. As these are often used as nonlinear
2061: preconditioners, monitoring the norm of their error is not a useful enterprise within
2062: their solution.
2064: .seealso: [](ch_snes), `SNESNormSchedule`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`
2065: @*/
2066: PetscErrorCode SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
2067: {
2068: PetscFunctionBegin;
2071: snes->normschedule = normschedule;
2072: PetscFunctionReturn(PETSC_SUCCESS);
2073: }
2075: /*@
2076: SNESGetNormSchedule - Gets the `SNESNormSchedule` used in convergence and monitoring
2077: of the `SNES` method.
2079: Logically Collective
2081: Input Parameters:
2082: + snes - the `SNES` context
2083: - normschedule - the type of the norm used
2085: Level: advanced
2087: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2088: @*/
2089: PetscErrorCode SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
2090: {
2091: PetscFunctionBegin;
2093: *normschedule = snes->normschedule;
2094: PetscFunctionReturn(PETSC_SUCCESS);
2095: }
2097: /*@
2098: SNESSetFunctionNorm - Sets the last computed residual norm.
2100: Logically Collective
2102: Input Parameters:
2103: + snes - the `SNES` context
2104: - norm - the value of the norm
2106: Level: developer
2108: .seealso: [](ch_snes), `SNES`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2109: @*/
2110: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
2111: {
2112: PetscFunctionBegin;
2114: snes->norm = norm;
2115: PetscFunctionReturn(PETSC_SUCCESS);
2116: }
2118: /*@
2119: SNESGetFunctionNorm - Gets the last computed norm of the residual
2121: Not Collective
2123: Input Parameter:
2124: . snes - the `SNES` context
2126: Output Parameter:
2127: . norm - the last computed residual norm
2129: Level: developer
2131: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2132: @*/
2133: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
2134: {
2135: PetscFunctionBegin;
2137: PetscAssertPointer(norm, 2);
2138: *norm = snes->norm;
2139: PetscFunctionReturn(PETSC_SUCCESS);
2140: }
2142: /*@
2143: SNESGetUpdateNorm - Gets the last computed norm of the solution update
2145: Not Collective
2147: Input Parameter:
2148: . snes - the `SNES` context
2150: Output Parameter:
2151: . ynorm - the last computed update norm
2153: Level: developer
2155: Note:
2156: The new solution is the current solution plus the update, so this norm is an indication of the size of the update
2158: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`
2159: @*/
2160: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2161: {
2162: PetscFunctionBegin;
2164: PetscAssertPointer(ynorm, 2);
2165: *ynorm = snes->ynorm;
2166: PetscFunctionReturn(PETSC_SUCCESS);
2167: }
2169: /*@
2170: SNESGetSolutionNorm - Gets the last computed norm of the solution
2172: Not Collective
2174: Input Parameter:
2175: . snes - the `SNES` context
2177: Output Parameter:
2178: . xnorm - the last computed solution norm
2180: Level: developer
2182: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`, `SNESGetUpdateNorm()`
2183: @*/
2184: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2185: {
2186: PetscFunctionBegin;
2188: PetscAssertPointer(xnorm, 2);
2189: *xnorm = snes->xnorm;
2190: PetscFunctionReturn(PETSC_SUCCESS);
2191: }
2193: /*@
2194: SNESSetFunctionType - Sets the `SNESFunctionType`
2195: of the `SNES` method.
2197: Logically Collective
2199: Input Parameters:
2200: + snes - the `SNES` context
2201: - type - the function type
2203: Level: developer
2205: Values of the function type\:
2206: + `SNES_FUNCTION_DEFAULT` - the default for the given `SNESType`
2207: . `SNES_FUNCTION_UNPRECONDITIONED` - an unpreconditioned function evaluation (this is the function provided with `SNESSetFunction()`
2208: - `SNES_FUNCTION_PRECONDITIONED` - a transformation of the function provided with `SNESSetFunction()`
2210: Note:
2211: Different `SNESType`s use this value in different ways
2213: .seealso: [](ch_snes), `SNES`, `SNESFunctionType`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2214: @*/
2215: PetscErrorCode SNESSetFunctionType(SNES snes, SNESFunctionType type)
2216: {
2217: PetscFunctionBegin;
2219: snes->functype = type;
2220: PetscFunctionReturn(PETSC_SUCCESS);
2221: }
2223: /*@
2224: SNESGetFunctionType - Gets the `SNESFunctionType` used in convergence and monitoring set with `SNESSetFunctionType()`
2225: of the SNES method.
2227: Logically Collective
2229: Input Parameters:
2230: + snes - the `SNES` context
2231: - type - the type of the function evaluation, see `SNESSetFunctionType()`
2233: Level: advanced
2235: .seealso: [](ch_snes), `SNESSetFunctionType()`, `SNESFunctionType`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2236: @*/
2237: PetscErrorCode SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2238: {
2239: PetscFunctionBegin;
2241: *type = snes->functype;
2242: PetscFunctionReturn(PETSC_SUCCESS);
2243: }
2245: /*@
2246: SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2247: use with composed nonlinear solvers.
2249: Input Parameters:
2250: + snes - the `SNES` context, usually of the `SNESType` `SNESNGS`
2251: . f - function evaluation routine to apply Gauss-Seidel, see `SNESNGSFn` for calling sequence
2252: - ctx - [optional] user-defined context for private data for the smoother evaluation routine (may be `NULL`)
2254: Level: intermediate
2256: Note:
2257: The `SNESNGS` routines are used by the composed nonlinear solver to generate
2258: a problem appropriate update to the solution, particularly `SNESFAS`.
2260: .seealso: [](ch_snes), `SNESNGS`, `SNESGetNGS()`, `SNESNCG`, `SNESGetFunction()`, `SNESComputeNGS()`, `SNESNGSFn`
2261: @*/
2262: PetscErrorCode SNESSetNGS(SNES snes, SNESNGSFn *f, PetscCtx ctx)
2263: {
2264: DM dm;
2266: PetscFunctionBegin;
2268: PetscCall(SNESGetDM(snes, &dm));
2269: PetscCall(DMSNESSetNGS(dm, f, ctx));
2270: PetscFunctionReturn(PETSC_SUCCESS);
2271: }
2273: /*@
2274: SNESPicardComputeMFFunction - Matrix-free residual $A(x) x - b(x)$ used by `SNESSetPicard()` when the operator is applied through `-snes_mf_operator`
2276: Collective
2278: Input Parameters:
2279: + snes - the `SNES` context
2280: . x - the current iterate
2281: - ctx - unused application context; the Picard callbacks are retrieved from the attached `DMSNES`
2283: Output Parameter:
2284: . f - the residual vector
2286: Level: developer
2288: Note:
2289: Uses a duplicate of `snes->jacobian_pre` because `snes->jacobian_pre` cannot be changed during the `KSPSolve()`.
2291: .seealso: [](ch_snes), `SNES`, `SNESSetPicard()`, `SNESPicardComputeFunction()`, `SNESPicardComputeJacobian()`
2292: @*/
2293: PetscErrorCode SNESPicardComputeMFFunction(SNES snes, Vec x, Vec f, PetscCtx ctx)
2294: {
2295: DM dm;
2296: DMSNES sdm;
2298: PetscFunctionBegin;
2299: PetscCall(SNESGetDM(snes, &dm));
2300: PetscCall(DMGetDMSNES(dm, &sdm));
2301: /* A(x)*x - b(x) */
2302: if (sdm->ops->computepfunction) {
2303: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2304: PetscCall(VecScale(f, -1.0));
2305: /* Cannot share nonzero pattern because of the possible use of SNESComputeJacobianDefault() */
2306: if (!snes->picard) PetscCall(MatDuplicate(snes->jacobian_pre, MAT_DO_NOT_COPY_VALUES, &snes->picard));
2307: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2308: PetscCall(MatMultAdd(snes->picard, x, f, f));
2309: } else {
2310: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2311: PetscCall(MatMult(snes->picard, x, f));
2312: }
2313: PetscFunctionReturn(PETSC_SUCCESS);
2314: }
2316: /*@
2317: SNESPicardComputeFunction - Compute the residual $A(x) x - b(x)$ using the callbacks registered by `SNESSetPicard()`
2319: Collective
2321: Input Parameters:
2322: + snes - the `SNES` context
2323: . x - the current iterate
2324: - ctx - unused application context; the Picard callbacks are retrieved from the attached `DMSNES`
2326: Output Parameter:
2327: . f - the residual vector
2329: Level: developer
2331: .seealso: [](ch_snes), `SNES`, `SNESSetPicard()`, `SNESPicardComputeMFFunction()`, `SNESPicardComputeJacobian()`
2332: @*/
2333: PetscErrorCode SNESPicardComputeFunction(SNES snes, Vec x, Vec f, PetscCtx ctx)
2334: {
2335: DM dm;
2336: DMSNES sdm;
2338: PetscFunctionBegin;
2339: PetscCall(SNESGetDM(snes, &dm));
2340: PetscCall(DMGetDMSNES(dm, &sdm));
2341: /* A(x)*x - b(x) */
2342: if (sdm->ops->computepfunction) {
2343: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2344: PetscCall(VecScale(f, -1.0));
2345: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2346: PetscCall(MatMultAdd(snes->jacobian_pre, x, f, f));
2347: } else {
2348: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2349: PetscCall(MatMult(snes->jacobian_pre, x, f));
2350: }
2351: PetscFunctionReturn(PETSC_SUCCESS);
2352: }
2354: /*@
2355: SNESPicardComputeJacobian - Trivial Jacobian assembly callback used by `SNESSetPicard()`; the Picard operator is filled in by `SNESPicardComputeFunction()`
2357: Collective
2359: Input Parameters:
2360: + snes - the `SNES` context
2361: . x1 - the current iterate (unused)
2362: . J - the Jacobian matrix to assemble
2363: . B - the preconditioning matrix (unused)
2364: - ctx - unused application context
2366: Level: developer
2368: Note:
2369: Only calls `MatAssemblyBegin()`/`MatAssemblyEnd()` on `J`, because the Picard iteration reuses the operator already assembled by `SNESPicardComputeFunction()`.
2371: .seealso: [](ch_snes), `SNES`, `SNESSetPicard()`, `SNESPicardComputeFunction()`, `SNESPicardComputeMFFunction()`
2372: @*/
2373: PetscErrorCode SNESPicardComputeJacobian(SNES snes, Vec x1, Mat J, Mat B, PetscCtx ctx)
2374: {
2375: PetscFunctionBegin;
2376: /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2377: /* must assembly if matrix-free to get the last SNES solution */
2378: PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
2379: PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
2380: PetscFunctionReturn(PETSC_SUCCESS);
2381: }
2383: /*@
2384: SNESSetPicard - Use `SNES` to solve the system $A(x) x = bp(x) + b $ via a Picard type iteration (Picard linearization)
2386: Logically Collective
2388: Input Parameters:
2389: + snes - the `SNES` context
2390: . r - vector to store function values, may be `NULL`
2391: . bp - function evaluation routine, may be `NULL`, for the calling sequence see `SNESFunctionFn`
2392: . Amat - matrix with which $A(x) x - bp(x) - b$ is to be computed
2393: . Pmat - matrix from which preconditioner is computed (usually the same as `Amat`)
2394: . J - function to compute matrix values, for the calling sequence see `SNESJacobianFn`
2395: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
2397: Level: intermediate
2399: Notes:
2400: It is often better to provide the nonlinear function $F()$ and some approximation to its Jacobian directly and use
2401: 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.
2403: One can call `SNESSetPicard()` or `SNESSetFunction()` (and possibly `SNESSetJacobian()`) but cannot call both
2405: Solves the equation $A(x) x = bp(x) + b$ via the defect correction algorithm $A(x^{n}) (x^{n+1} - x^{n}) = bp(x^{n}) + b - A(x^{n})x^{n}$.
2406: When an exact solver is used this corresponds to the "classic" Picard $A(x^{n}) x^{n+1} = bp(x^{n}) + b$ iteration.
2408: Run with `-snes_mf_operator` to solve the system with Newton's method using $A(x^{n})$ to construct the preconditioner.
2410: We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2411: the direct Picard iteration $A(x^n) x^{n+1} = bp(x^n) + b$
2413: 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
2414: 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
2415: different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument \:-).
2417: 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
2418: $A(x^{n})$ is used to build the preconditioner
2420: When used with `-snes_fd` this will compute the true Jacobian (very slowly one column at a time) and thus represent Newton's method.
2422: 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
2423: 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
2424: 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`.
2425: See the comment in src/snes/tutorials/ex15.c.
2427: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESGetPicard()`, `SNESLineSearchPreCheckPicard()`,
2428: `SNESFunctionFn`, `SNESJacobianFn`
2429: @*/
2430: PetscErrorCode SNESSetPicard(SNES snes, Vec r, SNESFunctionFn *bp, Mat Amat, Mat Pmat, SNESJacobianFn *J, PetscCtx ctx)
2431: {
2432: DM dm;
2434: PetscFunctionBegin;
2436: PetscCall(SNESGetDM(snes, &dm));
2437: PetscCall(DMSNESSetPicard(dm, bp, J, ctx));
2438: PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2439: PetscCall(SNESSetFunction(snes, r, SNESPicardComputeFunction, ctx));
2440: PetscCall(SNESSetJacobian(snes, Amat, Pmat, SNESPicardComputeJacobian, ctx));
2441: PetscFunctionReturn(PETSC_SUCCESS);
2442: }
2444: /*@
2445: SNESGetPicard - Returns the context for the Picard iteration
2447: Not Collective, but `Vec` is parallel if `SNES` is parallel. Collective if `Vec` is requested, but has not been created yet.
2449: Input Parameter:
2450: . snes - the `SNES` context
2452: Output Parameters:
2453: + r - the function (or `NULL`)
2454: . f - the function (or `NULL`); for calling sequence see `SNESFunctionFn`
2455: . Amat - the matrix used to defined the operation A(x) x - b(x) (or `NULL`)
2456: . Pmat - the matrix from which the preconditioner will be constructed (or `NULL`)
2457: . J - the function for matrix evaluation (or `NULL`); for calling sequence see `SNESJacobianFn`
2458: - ctx - the function context (or `NULL`)
2460: Level: advanced
2462: .seealso: [](ch_snes), `SNESSetFunction()`, `SNESSetPicard()`, `SNESGetFunction()`, `SNESGetJacobian()`, `SNESGetDM()`, `SNESFunctionFn`, `SNESJacobianFn`
2463: @*/
2464: PetscErrorCode SNESGetPicard(SNES snes, Vec *r, SNESFunctionFn **f, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, PetscCtxRt ctx)
2465: {
2466: DM dm;
2468: PetscFunctionBegin;
2470: PetscCall(SNESGetFunction(snes, r, NULL, NULL));
2471: PetscCall(SNESGetJacobian(snes, Amat, Pmat, NULL, NULL));
2472: PetscCall(SNESGetDM(snes, &dm));
2473: PetscCall(DMSNESGetPicard(dm, f, J, ctx));
2474: PetscFunctionReturn(PETSC_SUCCESS);
2475: }
2477: /*@
2478: SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the nonlinear problem
2480: Logically Collective
2482: Input Parameters:
2483: + snes - the `SNES` context
2484: . func - function evaluation routine, see `SNESInitialGuessFn` for the calling sequence
2485: - ctx - [optional] user-defined context for private data for the
2486: function evaluation routine (may be `NULL`)
2488: Level: intermediate
2490: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESInitialGuessFn`
2491: @*/
2492: PetscErrorCode SNESSetComputeInitialGuess(SNES snes, SNESInitialGuessFn *func, PetscCtx ctx)
2493: {
2494: PetscFunctionBegin;
2496: if (func) snes->ops->computeinitialguess = func;
2497: if (ctx) snes->initialguessP = ctx;
2498: PetscFunctionReturn(PETSC_SUCCESS);
2499: }
2501: /*@
2502: SNESGetRhs - Gets the vector for solving F(x) = `rhs`. If `rhs` is not set
2503: it assumes a zero right-hand side.
2505: Logically Collective
2507: Input Parameter:
2508: . snes - the `SNES` context
2510: Output Parameter:
2511: . rhs - the right-hand side vector or `NULL` if there is no right-hand side vector
2513: Level: intermediate
2515: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetFunction()`
2516: @*/
2517: PetscErrorCode SNESGetRhs(SNES snes, Vec *rhs)
2518: {
2519: PetscFunctionBegin;
2521: PetscAssertPointer(rhs, 2);
2522: *rhs = snes->vec_rhs;
2523: PetscFunctionReturn(PETSC_SUCCESS);
2524: }
2526: /*@
2527: SNESComputeFunction - Calls the function that has been set with `SNESSetFunction()`.
2529: Collective
2531: Input Parameters:
2532: + snes - the `SNES` context
2533: - x - input vector
2535: Output Parameter:
2536: . f - function vector, as set by `SNESSetFunction()`
2538: Level: developer
2540: Notes:
2541: `SNESComputeFunction()` is typically used within nonlinear solvers
2542: implementations, so users would not generally call this routine themselves.
2544: When solving for $F(x) = b$, this routine computes $f = F(x) - b$.
2546: This function usually appears in the pattern.
2547: .vb
2548: SNESComputeFunction(snes, x, f);
2549: VecNorm(f, &fnorm);
2550: SNESCheckFunctionDomainError(snes, fnorm); or SNESLineSearchCheckFunctionDomainError(ls, fnorm);
2551: .ve
2552: to collectively handle the use of `SNESSetFunctionDomainError()` in the provided callback function.
2554: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeMFFunction()`, `SNESSetFunctionDomainError()`
2555: @*/
2556: PetscErrorCode SNESComputeFunction(SNES snes, Vec x, Vec f)
2557: {
2558: DM dm;
2559: DMSNES sdm;
2561: PetscFunctionBegin;
2565: PetscCheckSameComm(snes, 1, x, 2);
2566: PetscCheckSameComm(snes, 1, f, 3);
2567: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2569: PetscCall(SNESGetDM(snes, &dm));
2570: PetscCall(DMGetDMSNES(dm, &sdm));
2571: 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().");
2572: if (sdm->ops->computefunction) {
2573: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, f, 0));
2574: PetscCall(VecLockReadPush(x));
2575: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2576: snes->functiondomainerror = PETSC_FALSE;
2577: {
2578: void *ctx;
2579: SNESFunctionFn *computefunction;
2580: PetscCall(DMSNESGetFunction(dm, &computefunction, &ctx));
2581: PetscCallBack("SNES callback function", (*computefunction)(snes, x, f, ctx));
2582: }
2583: PetscCall(VecLockReadPop(x));
2584: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, f, 0));
2585: } else /* if (snes->vec_rhs) */ {
2586: PetscCall(MatMult(snes->jacobian, x, f));
2587: }
2588: if (snes->vec_rhs) PetscCall(VecAXPY(f, -1.0, snes->vec_rhs));
2589: snes->nfuncs++;
2590: /*
2591: domainerror might not be set on all processes; so we tag vector locally with infinity and the next inner product or norm will
2592: propagate the value to all processes
2593: */
2594: PetscCall(VecFlag(f, snes->functiondomainerror));
2595: PetscFunctionReturn(PETSC_SUCCESS);
2596: }
2598: /*@
2599: SNESComputeMFFunction - Calls the function that has been set with `DMSNESSetMFFunction()`.
2601: Collective
2603: Input Parameters:
2604: + snes - the `SNES` context
2605: - x - input vector
2607: Output Parameter:
2608: . y - output vector
2610: Level: developer
2612: Notes:
2613: `SNESComputeMFFunction()` is used within the matrix-vector products called by the matrix created with `MatCreateSNESMF()`
2614: so users would not generally call this routine themselves.
2616: Since this function is intended for use with finite differencing it does not subtract the right-hand side vector provided with `SNESSolve()`
2617: while `SNESComputeFunction()` does. As such, this routine cannot be used with `MatMFFDSetBase()` with a provided F function value even if it applies the
2618: 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.
2620: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `MatCreateSNESMF()`, `DMSNESSetMFFunction()`
2621: @*/
2622: PetscErrorCode SNESComputeMFFunction(SNES snes, Vec x, Vec y)
2623: {
2624: DM dm;
2625: DMSNES sdm;
2627: PetscFunctionBegin;
2631: PetscCheckSameComm(snes, 1, x, 2);
2632: PetscCheckSameComm(snes, 1, y, 3);
2633: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2635: PetscCall(SNESGetDM(snes, &dm));
2636: PetscCall(DMGetDMSNES(dm, &sdm));
2637: PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2638: PetscCall(VecLockReadPush(x));
2639: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2640: snes->functiondomainerror = PETSC_FALSE;
2641: PetscCallBack("SNES callback function", (*sdm->ops->computemffunction)(snes, x, y, sdm->mffunctionctx));
2642: PetscCall(VecLockReadPop(x));
2643: PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2644: snes->nfuncs++;
2645: /*
2646: domainerror might not be set on all processes; so we tag vector locally with infinity and the next inner product or norm will
2647: propagate the value to all processes
2648: */
2649: PetscCall(VecFlag(y, snes->functiondomainerror));
2650: PetscFunctionReturn(PETSC_SUCCESS);
2651: }
2653: /*@
2654: SNESComputeNGS - Calls the Gauss-Seidel function that has been set with `SNESSetNGS()`.
2656: Collective
2658: Input Parameters:
2659: + snes - the `SNES` context
2660: . x - input vector
2661: - b - rhs vector
2663: Output Parameter:
2664: . x - new solution vector
2666: Level: developer
2668: Note:
2669: `SNESComputeNGS()` is typically used within composed nonlinear solver
2670: implementations, so most users would not generally call this routine
2671: themselves.
2673: .seealso: [](ch_snes), `SNESNGSFn`, `SNESSetNGS()`, `SNESComputeFunction()`, `SNESNGS`
2674: @*/
2675: PetscErrorCode SNESComputeNGS(SNES snes, Vec b, Vec x)
2676: {
2677: DM dm;
2678: DMSNES sdm;
2680: PetscFunctionBegin;
2684: PetscCheckSameComm(snes, 1, x, 3);
2685: if (b) PetscCheckSameComm(snes, 1, b, 2);
2686: if (b) PetscCall(VecValidValues_Internal(b, 2, PETSC_TRUE));
2687: PetscCall(PetscLogEventBegin(SNES_NGSEval, snes, x, b, 0));
2688: PetscCall(SNESGetDM(snes, &dm));
2689: PetscCall(DMGetDMSNES(dm, &sdm));
2690: PetscCheck(sdm->ops->computegs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2691: if (b) PetscCall(VecLockReadPush(b));
2692: PetscCallBack("SNES callback NGS", (*sdm->ops->computegs)(snes, x, b, sdm->gsctx));
2693: if (b) PetscCall(VecLockReadPop(b));
2694: PetscCall(PetscLogEventEnd(SNES_NGSEval, snes, x, b, 0));
2695: PetscFunctionReturn(PETSC_SUCCESS);
2696: }
2698: static PetscErrorCode SNESComputeFunction_FD(SNES snes, Vec Xin, Vec G)
2699: {
2700: Vec X;
2701: PetscScalar *g;
2702: PetscReal f, f2;
2703: PetscInt low, high, N, i;
2704: PetscBool flg;
2705: PetscReal h = .5 * PETSC_SQRT_MACHINE_EPSILON;
2707: PetscFunctionBegin;
2708: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_fd_delta", &h, &flg));
2709: PetscCall(VecDuplicate(Xin, &X));
2710: PetscCall(VecCopy(Xin, X));
2711: PetscCall(VecGetSize(X, &N));
2712: PetscCall(VecGetOwnershipRange(X, &low, &high));
2713: PetscCall(VecSetOption(X, VEC_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE));
2714: PetscCall(VecGetArray(G, &g));
2715: for (i = 0; i < N; i++) {
2716: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2717: PetscCall(VecAssemblyBegin(X));
2718: PetscCall(VecAssemblyEnd(X));
2719: PetscCall(SNESComputeObjective(snes, X, &f));
2720: PetscCall(VecSetValue(X, i, 2.0 * h, ADD_VALUES));
2721: PetscCall(VecAssemblyBegin(X));
2722: PetscCall(VecAssemblyEnd(X));
2723: PetscCall(SNESComputeObjective(snes, X, &f2));
2724: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2725: PetscCall(VecAssemblyBegin(X));
2726: PetscCall(VecAssemblyEnd(X));
2727: if (i >= low && i < high) g[i - low] = (f2 - f) / (2.0 * h);
2728: }
2729: PetscCall(VecRestoreArray(G, &g));
2730: PetscCall(VecDestroy(&X));
2731: PetscFunctionReturn(PETSC_SUCCESS);
2732: }
2734: /*@
2735: SNESTestFunction - Computes the difference between the computed and finite-difference functions
2737: Collective
2739: Input Parameter:
2740: . snes - the `SNES` context
2742: Options Database Keys:
2743: + -snes_test_function - compare the user provided function with one compute via finite differences to check for errors.
2744: - -snes_test_function_view - display the user provided function, the finite difference function and the difference
2746: Level: developer
2748: .seealso: [](ch_snes), `SNESTestJacobian()`, `SNESSetFunction()`, `SNESComputeFunction()`
2749: @*/
2750: PetscErrorCode SNESTestFunction(SNES snes)
2751: {
2752: Vec x, g1, g2, g3;
2753: PetscBool complete_print = PETSC_FALSE;
2754: PetscReal hcnorm, fdnorm, hcmax, fdmax, diffmax, diffnorm;
2755: PetscScalar dot;
2756: MPI_Comm comm;
2757: PetscViewer viewer, mviewer;
2758: PetscViewerFormat format;
2759: PetscInt tabs;
2760: static PetscBool directionsprinted = PETSC_FALSE;
2761: SNESObjectiveFn *objective;
2763: PetscFunctionBegin;
2764: PetscCall(SNESGetObjective(snes, &objective, NULL));
2765: if (!objective) PetscFunctionReturn(PETSC_SUCCESS);
2767: PetscObjectOptionsBegin((PetscObject)snes);
2768: PetscCall(PetscOptionsViewer("-snes_test_function_view", "View difference between hand-coded and finite difference function element entries", "None", &mviewer, &format, &complete_print));
2769: PetscOptionsEnd();
2771: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2772: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2773: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2774: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2775: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Function -------------\n"));
2776: if (!complete_print && !directionsprinted) {
2777: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_function_view and optionally -snes_test_function <threshold> to show difference\n"));
2778: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference function entries greater than <threshold>.\n"));
2779: }
2780: if (!directionsprinted) {
2781: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Function, if (for double precision runs) ||F - Ffd||/||F|| is\n"));
2782: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Function is probably correct.\n"));
2783: directionsprinted = PETSC_TRUE;
2784: }
2785: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2787: PetscCall(SNESGetSolution(snes, &x));
2788: PetscCall(VecDuplicate(x, &g1));
2789: PetscCall(VecDuplicate(x, &g2));
2790: PetscCall(VecDuplicate(x, &g3));
2791: PetscCall(SNESComputeFunction(snes, x, g1)); /* does not handle use of SNESSetFunctionDomainError() correctly */
2792: PetscCall(SNESComputeFunction_FD(snes, x, g2));
2794: PetscCall(VecNorm(g2, NORM_2, &fdnorm));
2795: PetscCall(VecNorm(g1, NORM_2, &hcnorm));
2796: PetscCall(VecNorm(g2, NORM_INFINITY, &fdmax));
2797: PetscCall(VecNorm(g1, NORM_INFINITY, &hcmax));
2798: PetscCall(VecDot(g1, g2, &dot));
2799: PetscCall(VecCopy(g1, g3));
2800: PetscCall(VecAXPY(g3, -1.0, g2));
2801: PetscCall(VecNorm(g3, NORM_2, &diffnorm));
2802: PetscCall(VecNorm(g3, NORM_INFINITY, &diffmax));
2803: PetscCall(PetscViewerASCIIPrintf(viewer, " ||Ffd|| %g, ||F|| = %g, angle cosine = (Ffd'F)/||Ffd||||F|| = %g\n", (double)fdnorm, (double)hcnorm, (double)(PetscRealPart(dot) / (fdnorm * hcnorm))));
2804: PetscCall(PetscViewerASCIIPrintf(viewer, " 2-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffnorm / PetscMax(hcnorm, fdnorm)), (double)diffnorm));
2805: PetscCall(PetscViewerASCIIPrintf(viewer, " max-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffmax / PetscMax(hcmax, fdmax)), (double)diffmax));
2807: if (complete_print) {
2808: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded function ----------\n"));
2809: PetscCall(VecView(g1, mviewer));
2810: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference function ----------\n"));
2811: PetscCall(VecView(g2, mviewer));
2812: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference function ----------\n"));
2813: PetscCall(VecView(g3, mviewer));
2814: }
2815: PetscCall(VecDestroy(&g1));
2816: PetscCall(VecDestroy(&g2));
2817: PetscCall(VecDestroy(&g3));
2819: if (complete_print) {
2820: PetscCall(PetscViewerPopFormat(mviewer));
2821: PetscCall(PetscViewerDestroy(&mviewer));
2822: }
2823: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2824: PetscFunctionReturn(PETSC_SUCCESS);
2825: }
2827: /*@
2828: SNESTestJacobian - Computes the difference between the computed and finite-difference Jacobians
2830: Collective
2832: Input Parameter:
2833: . snes - the `SNES` context
2835: Output Parameters:
2836: + Jnorm - the Frobenius norm of the computed Jacobian, or `NULL`
2837: - diffNorm - the Frobenius norm of the difference of the computed and finite-difference Jacobians, or `NULL`
2839: Options Database Keys:
2840: + -snes_test_jacobian [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.
2841: - -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference
2843: Level: developer
2845: Note:
2846: Directions and norms are printed to stdout if `diffNorm` is `NULL`.
2848: .seealso: [](ch_snes), `SNESTestFunction()`, `SNESSetJacobian()`, `SNESComputeJacobian()`
2849: @*/
2850: PetscErrorCode SNESTestJacobian(SNES snes, PetscReal *Jnorm, PetscReal *diffNorm)
2851: {
2852: Mat A, B, C, D, jacobian;
2853: Vec x = snes->vec_sol, f;
2854: PetscReal nrm, gnorm;
2855: PetscReal threshold = 1.e-5;
2856: void *functx;
2857: PetscBool complete_print = PETSC_FALSE, threshold_print = PETSC_FALSE, flg, istranspose;
2858: PetscBool silent = diffNorm != PETSC_NULLPTR ? PETSC_TRUE : PETSC_FALSE;
2859: PetscViewer viewer, mviewer;
2860: MPI_Comm comm;
2861: PetscInt tabs;
2862: static PetscBool directionsprinted = PETSC_FALSE;
2863: PetscViewerFormat format;
2865: PetscFunctionBegin;
2866: PetscObjectOptionsBegin((PetscObject)snes);
2867: PetscCall(PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold, NULL));
2868: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display", "-snes_test_jacobian_view", "3.13", NULL));
2869: PetscCall(PetscOptionsViewer("-snes_test_jacobian_view", "View difference between hand-coded and finite difference Jacobians element entries", "None", &mviewer, &format, &complete_print));
2870: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display_threshold", "-snes_test_jacobian", "3.13", "-snes_test_jacobian accepts an optional threshold (since v3.10)"));
2871: 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));
2872: PetscOptionsEnd();
2874: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2875: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2876: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2877: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2878: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian -------------\n"));
2879: if (!complete_print && !silent && !directionsprinted) {
2880: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n"));
2881: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference Jacobian entries greater than <threshold>.\n"));
2882: }
2883: if (!directionsprinted && !silent) {
2884: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n"));
2885: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Jacobian is probably correct.\n"));
2886: directionsprinted = PETSC_TRUE;
2887: }
2888: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2890: PetscCall(PetscObjectTypeCompare((PetscObject)snes->jacobian, MATMFFD, &flg));
2891: if (!flg) jacobian = snes->jacobian;
2892: else jacobian = snes->jacobian_pre;
2894: if (!x) PetscCall(MatCreateVecs(jacobian, &x, NULL));
2895: else PetscCall(PetscObjectReference((PetscObject)x));
2896: PetscCall(VecDuplicate(x, &f));
2898: /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2899: PetscCall(SNESComputeFunction(snes, x, f));
2900: PetscCall(VecDestroy(&f));
2901: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESKSPTRANSPOSEONLY, &istranspose));
2902: while (jacobian) {
2903: Mat JT = NULL, Jsave = NULL;
2905: if (istranspose) {
2906: PetscCall(MatCreateTranspose(jacobian, &JT));
2907: Jsave = jacobian;
2908: jacobian = JT;
2909: }
2910: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)jacobian, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
2911: if (flg) {
2912: A = jacobian;
2913: PetscCall(PetscObjectReference((PetscObject)A));
2914: } else {
2915: PetscCall(MatComputeOperator(jacobian, MATAIJ, &A));
2916: }
2918: PetscCall(MatDuplicate(A, MAT_DO_NOT_COPY_VALUES, &B));
2919: PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2921: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
2922: PetscCall(SNESComputeJacobianDefault(snes, x, B, B, functx));
2924: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &D));
2925: PetscCall(MatAYPX(D, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2926: PetscCall(MatNorm(D, NORM_FROBENIUS, &nrm));
2927: PetscCall(MatNorm(A, NORM_FROBENIUS, &gnorm));
2928: PetscCall(MatDestroy(&D));
2929: if (!gnorm) gnorm = 1; /* just in case */
2930: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n", (double)(nrm / gnorm), (double)nrm));
2931: if (complete_print) {
2932: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded Jacobian ----------\n"));
2933: PetscCall(MatView(A, mviewer));
2934: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference Jacobian ----------\n"));
2935: PetscCall(MatView(B, mviewer));
2936: }
2938: if (threshold_print || complete_print) {
2939: PetscInt Istart, Iend, *ccols, bncols, cncols, j, row;
2940: PetscScalar *cvals;
2941: const PetscInt *bcols;
2942: const PetscScalar *bvals;
2944: PetscCall(MatDuplicate(A, MAT_DO_NOT_COPY_VALUES, &C));
2945: PetscCall(MatSetOption(C, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2947: PetscCall(MatAYPX(B, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2948: PetscCall(MatGetOwnershipRange(B, &Istart, &Iend));
2950: for (row = Istart; row < Iend; row++) {
2951: PetscCall(MatGetRow(B, row, &bncols, &bcols, &bvals));
2952: PetscCall(PetscMalloc2(bncols, &ccols, bncols, &cvals));
2953: for (j = 0, cncols = 0; j < bncols; j++) {
2954: if (PetscAbsScalar(bvals[j]) > threshold) {
2955: ccols[cncols] = bcols[j];
2956: cvals[cncols] = bvals[j];
2957: cncols += 1;
2958: }
2959: }
2960: if (cncols) PetscCall(MatSetValues(C, 1, &row, cncols, ccols, cvals, INSERT_VALUES));
2961: PetscCall(MatRestoreRow(B, row, &bncols, &bcols, &bvals));
2962: PetscCall(PetscFree2(ccols, cvals));
2963: }
2964: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2965: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2966: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n", (double)threshold));
2967: PetscCall(MatView(C, complete_print ? mviewer : viewer));
2968: PetscCall(MatDestroy(&C));
2969: }
2970: PetscCall(MatDestroy(&A));
2971: PetscCall(MatDestroy(&B));
2972: PetscCall(MatDestroy(&JT));
2973: if (Jsave) jacobian = Jsave;
2974: if (jacobian != snes->jacobian_pre) {
2975: jacobian = snes->jacobian_pre;
2976: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian for preconditioner -------------\n"));
2977: } else jacobian = NULL;
2978: }
2979: PetscCall(VecDestroy(&x));
2980: if (complete_print) PetscCall(PetscViewerPopFormat(mviewer));
2981: PetscCall(PetscViewerDestroy(&mviewer));
2982: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2984: if (Jnorm) *Jnorm = gnorm;
2985: if (diffNorm) *diffNorm = nrm;
2986: PetscFunctionReturn(PETSC_SUCCESS);
2987: }
2989: /*@
2990: SNESComputeJacobian - Computes the Jacobian matrix that has been set with `SNESSetJacobian()`.
2992: Collective
2994: Input Parameters:
2995: + snes - the `SNES` context
2996: - X - input vector
2998: Output Parameters:
2999: + A - Jacobian matrix
3000: - B - optional matrix for building the preconditioner, usually the same as `A`
3002: Options Database Keys:
3003: + -snes_lag_preconditioner lag - how often to rebuild preconditioner
3004: . -snes_lag_jacobian lag - how often to rebuild Jacobian
3005: . -snes_test_jacobian [threshold] - compare the user provided Jacobian with one compute via finite differences to check for errors.
3006: If a threshold is given, display only those entries whose difference is greater than the threshold.
3007: . -snes_test_jacobian_view [viewer] - 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
3008: . -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
3009: . -snes_compare_explicit_draw - Compare the computed Jacobian to the finite difference Jacobian and draw the result
3010: . -snes_compare_explicit_contour - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
3011: . -snes_compare_operator - Make the comparison options above use the operator instead of the matrix used to construct the preconditioner
3012: . -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
3013: . -snes_compare_coloring_display - Compute the finite difference Jacobian using coloring and display verbose differences
3014: . -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
3015: . -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
3016: . -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
3017: . -snes_compare_coloring_draw - Compute the finite difference Jacobian using coloring and draw differences
3018: - -snes_compare_coloring_draw_contour - Compute the finite difference Jacobian using coloring and show contours of matrices and differences
3020: Level: developer
3022: Note:
3023: Most users should not need to explicitly call this routine, as it
3024: is used internally within the nonlinear solvers.
3026: Developer Note:
3027: 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
3028: with the `SNESType` of test that has been removed.
3030: .seealso: [](ch_snes), `SNESSetJacobian()`, `KSPSetOperators()`, `MatStructure`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`,
3031: `SNESSetJacobianDomainError()`, `SNESCheckJacobianDomainError()`, `SNESSetCheckJacobianDomainError()`
3032: @*/
3033: PetscErrorCode SNESComputeJacobian(SNES snes, Vec X, Mat A, Mat B)
3034: {
3035: PetscBool flag;
3036: DM dm;
3037: DMSNES sdm;
3038: KSP ksp;
3040: PetscFunctionBegin;
3043: PetscCheckSameComm(snes, 1, X, 2);
3044: PetscCall(VecValidValues_Internal(X, 2, PETSC_TRUE));
3045: PetscCall(SNESGetDM(snes, &dm));
3046: PetscCall(DMGetDMSNES(dm, &sdm));
3048: /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix-free */
3049: if (snes->lagjacobian == -2) {
3050: snes->lagjacobian = -1;
3052: PetscCall(PetscInfo(snes, "Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n"));
3053: } else if (snes->lagjacobian == -1) {
3054: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is -1\n"));
3055: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
3056: if (flag) {
3057: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
3058: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
3059: }
3060: PetscFunctionReturn(PETSC_SUCCESS);
3061: } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
3062: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagjacobian, snes->iter));
3063: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
3064: if (flag) {
3065: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
3066: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
3067: }
3068: PetscFunctionReturn(PETSC_SUCCESS);
3069: }
3070: if (snes->npc && snes->npcside == PC_LEFT) {
3071: /* SNESASPIN uses SNESNASM as the nonlinear preconditioner. When SNESNASM
3072: is done solving the sub-systems it calls the user-provided Jacobian function
3073: (corresponding to the unpreconditioned residual) retrieved through the DM.
3074: Consequently it would be redundant to call the Jacobian function here. In
3075: the future we may move the outer Jacobian function call out of SNESNASM
3076: in which case no special casing will be required here. */
3077: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESASPIN, &flag));
3078: if (flag) {
3079: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
3080: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
3081: PetscFunctionReturn(PETSC_SUCCESS);
3082: }
3083: }
3085: PetscCall(PetscLogEventBegin(SNES_JacobianEval, snes, X, A, B));
3086: PetscCall(VecLockReadPush(X));
3087: {
3088: void *ctx;
3089: SNESJacobianFn *J;
3090: PetscCall(DMSNESGetJacobian(dm, &J, &ctx));
3091: PetscCallBack("SNES callback Jacobian", (*J)(snes, X, A, B, ctx));
3092: }
3093: PetscCall(VecLockReadPop(X));
3094: PetscCall(PetscLogEventEnd(SNES_JacobianEval, snes, X, A, B));
3096: /* attach latest linearization point to the matrix used to construct the preconditioner */
3097: PetscCall(PetscObjectCompose((PetscObject)B, "__SNES_latest_X", (PetscObject)X));
3099: /* the next line ensures that snes->ksp exists */
3100: PetscCall(SNESGetKSP(snes, &ksp));
3101: if (snes->lagpreconditioner == -2) {
3102: PetscCall(PetscInfo(snes, "Rebuilding preconditioner exactly once since lag is -2\n"));
3103: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
3104: snes->lagpreconditioner = -1;
3105: } else if (snes->lagpreconditioner == -1) {
3106: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is -1\n"));
3107: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
3108: } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
3109: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagpreconditioner, snes->iter));
3110: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
3111: } else {
3112: PetscCall(PetscInfo(snes, "Rebuilding preconditioner\n"));
3113: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
3114: }
3116: /* monkey business to allow testing Jacobians in multilevel solvers.
3117: This is needed because the SNESTestXXX interface does not accept vectors and matrices */
3118: {
3119: Vec xsave = snes->vec_sol;
3120: Mat jacobiansave = snes->jacobian;
3121: Mat jacobian_presave = snes->jacobian_pre;
3123: snes->vec_sol = X;
3124: snes->jacobian = A;
3125: snes->jacobian_pre = B;
3126: if (snes->testFunc) PetscCall(SNESTestFunction(snes));
3127: if (snes->testJac) PetscCall(SNESTestJacobian(snes, NULL, NULL));
3129: snes->vec_sol = xsave;
3130: snes->jacobian = jacobiansave;
3131: snes->jacobian_pre = jacobian_presave;
3132: }
3134: {
3135: PetscBool flag = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_operator = PETSC_FALSE;
3136: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit", NULL, NULL, &flag));
3137: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw", NULL, NULL, &flag_draw));
3138: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw_contour", NULL, NULL, &flag_contour));
3139: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_operator", NULL, NULL, &flag_operator));
3140: if (flag || flag_draw || flag_contour) {
3141: Mat Bexp_mine = NULL, Bexp, FDexp;
3142: PetscViewer vdraw, vstdout;
3143: PetscBool flg;
3144: if (flag_operator) {
3145: PetscCall(MatComputeOperator(A, MATAIJ, &Bexp_mine));
3146: Bexp = Bexp_mine;
3147: } else {
3148: /* See if the matrix used to construct the preconditioner can be viewed and added directly */
3149: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)B, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
3150: if (flg) Bexp = B;
3151: else {
3152: /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
3153: PetscCall(MatComputeOperator(B, MATAIJ, &Bexp_mine));
3154: Bexp = Bexp_mine;
3155: }
3156: }
3157: PetscCall(MatConvert(Bexp, MATSAME, MAT_INITIAL_MATRIX, &FDexp));
3158: PetscCall(SNESComputeJacobianDefault(snes, X, FDexp, FDexp, NULL));
3159: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3160: if (flag_draw || flag_contour) {
3161: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Explicit Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3162: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3163: } else vdraw = NULL;
3164: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit %s\n", flag_operator ? "Jacobian" : "preconditioning Jacobian"));
3165: if (flag) PetscCall(MatView(Bexp, vstdout));
3166: if (vdraw) PetscCall(MatView(Bexp, vdraw));
3167: PetscCall(PetscViewerASCIIPrintf(vstdout, "Finite difference Jacobian\n"));
3168: if (flag) PetscCall(MatView(FDexp, vstdout));
3169: if (vdraw) PetscCall(MatView(FDexp, vdraw));
3170: PetscCall(MatAYPX(FDexp, -1.0, Bexp, SAME_NONZERO_PATTERN));
3171: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian\n"));
3172: if (flag) PetscCall(MatView(FDexp, vstdout));
3173: if (vdraw) { /* Always use contour for the difference */
3174: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3175: PetscCall(MatView(FDexp, vdraw));
3176: PetscCall(PetscViewerPopFormat(vdraw));
3177: }
3178: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3179: PetscCall(PetscViewerDestroy(&vdraw));
3180: PetscCall(MatDestroy(&Bexp_mine));
3181: PetscCall(MatDestroy(&FDexp));
3182: }
3183: }
3184: {
3185: PetscBool flag = PETSC_FALSE, flag_display = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_threshold = PETSC_FALSE;
3186: PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON, threshold_rtol = 10 * PETSC_SQRT_MACHINE_EPSILON;
3187: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring", NULL, NULL, &flag));
3188: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_display", NULL, NULL, &flag_display));
3189: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw", NULL, NULL, &flag_draw));
3190: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw_contour", NULL, NULL, &flag_contour));
3191: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold", NULL, NULL, &flag_threshold));
3192: if (flag_threshold) {
3193: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_rtol", &threshold_rtol, NULL));
3194: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_atol", &threshold_atol, NULL));
3195: }
3196: if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
3197: Mat Bfd;
3198: PetscViewer vdraw, vstdout;
3199: MatColoring coloring;
3200: ISColoring iscoloring;
3201: MatFDColoring matfdcoloring;
3202: SNESFunctionFn *func;
3203: void *funcctx;
3204: PetscReal norm1, norm2, normmax;
3206: PetscCall(MatDuplicate(B, MAT_DO_NOT_COPY_VALUES, &Bfd));
3207: PetscCall(MatColoringCreate(Bfd, &coloring));
3208: PetscCall(MatColoringSetType(coloring, MATCOLORINGSL));
3209: PetscCall(MatColoringSetFromOptions(coloring));
3210: PetscCall(MatColoringApply(coloring, &iscoloring));
3211: PetscCall(MatColoringDestroy(&coloring));
3212: PetscCall(MatFDColoringCreate(Bfd, iscoloring, &matfdcoloring));
3213: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3214: PetscCall(MatFDColoringSetUp(Bfd, iscoloring, matfdcoloring));
3215: PetscCall(ISColoringDestroy(&iscoloring));
3217: /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
3218: PetscCall(SNESGetFunction(snes, NULL, &func, &funcctx));
3219: PetscCall(MatFDColoringSetFunction(matfdcoloring, (MatFDColoringFn *)func, funcctx));
3220: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring, ((PetscObject)snes)->prefix));
3221: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring, "coloring_"));
3222: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3223: PetscCall(MatFDColoringApply(Bfd, matfdcoloring, X, snes));
3224: PetscCall(MatFDColoringDestroy(&matfdcoloring));
3226: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3227: if (flag_draw || flag_contour) {
3228: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Colored Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3229: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3230: } else vdraw = NULL;
3231: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit preconditioning Jacobian\n"));
3232: if (flag_display) PetscCall(MatView(B, vstdout));
3233: if (vdraw) PetscCall(MatView(B, vdraw));
3234: PetscCall(PetscViewerASCIIPrintf(vstdout, "Colored Finite difference Jacobian\n"));
3235: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3236: if (vdraw) PetscCall(MatView(Bfd, vdraw));
3237: PetscCall(MatAYPX(Bfd, -1.0, B, SAME_NONZERO_PATTERN));
3238: PetscCall(MatNorm(Bfd, NORM_1, &norm1));
3239: PetscCall(MatNorm(Bfd, NORM_FROBENIUS, &norm2));
3240: PetscCall(MatNorm(Bfd, NORM_MAX, &normmax));
3241: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n", (double)norm1, (double)norm2, (double)normmax));
3242: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3243: if (vdraw) { /* Always use contour for the difference */
3244: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3245: PetscCall(MatView(Bfd, vdraw));
3246: PetscCall(PetscViewerPopFormat(vdraw));
3247: }
3248: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3250: if (flag_threshold) {
3251: PetscInt bs, rstart, rend, i;
3252: PetscCall(MatGetBlockSize(B, &bs));
3253: PetscCall(MatGetOwnershipRange(B, &rstart, &rend));
3254: for (i = rstart; i < rend; i++) {
3255: const PetscScalar *ba, *ca;
3256: const PetscInt *bj, *cj;
3257: PetscInt bn, cn, j, maxentrycol = -1, maxdiffcol = -1, maxrdiffcol = -1;
3258: PetscReal maxentry = 0, maxdiff = 0, maxrdiff = 0;
3259: PetscCall(MatGetRow(B, i, &bn, &bj, &ba));
3260: PetscCall(MatGetRow(Bfd, i, &cn, &cj, &ca));
3261: PetscCheck(bn == cn, ((PetscObject)A)->comm, PETSC_ERR_PLIB, "Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
3262: for (j = 0; j < bn; j++) {
3263: PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3264: if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
3265: maxentrycol = bj[j];
3266: maxentry = PetscRealPart(ba[j]);
3267: }
3268: if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
3269: maxdiffcol = bj[j];
3270: maxdiff = PetscRealPart(ca[j]);
3271: }
3272: if (rdiff > maxrdiff) {
3273: maxrdiffcol = bj[j];
3274: maxrdiff = rdiff;
3275: }
3276: }
3277: if (maxrdiff > 1) {
3278: 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));
3279: for (j = 0; j < bn; j++) {
3280: PetscReal rdiff;
3281: rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3282: if (rdiff > 1) PetscCall(PetscViewerASCIIPrintf(vstdout, " (%" PetscInt_FMT ",%g:%g)", bj[j], (double)PetscRealPart(ba[j]), (double)PetscRealPart(ca[j])));
3283: }
3284: PetscCall(PetscViewerASCIIPrintf(vstdout, "\n"));
3285: }
3286: PetscCall(MatRestoreRow(B, i, &bn, &bj, &ba));
3287: PetscCall(MatRestoreRow(Bfd, i, &cn, &cj, &ca));
3288: }
3289: }
3290: PetscCall(PetscViewerDestroy(&vdraw));
3291: PetscCall(MatDestroy(&Bfd));
3292: }
3293: }
3294: PetscFunctionReturn(PETSC_SUCCESS);
3295: }
3297: /*@
3298: SNESSetJacobian - Sets the function to compute Jacobian as well as the
3299: location to store the matrix.
3301: Logically Collective
3303: Input Parameters:
3304: + snes - the `SNES` context
3305: . Amat - the matrix that defines the (approximate) Jacobian
3306: . Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
3307: . J - Jacobian evaluation routine (if `NULL` then `SNES` retains any previously set value), see `SNESJacobianFn` for details
3308: - ctx - [optional] user-defined context for private data for the
3309: Jacobian evaluation routine (may be `NULL`) (if `NULL` then `SNES` retains any previously set value)
3311: Level: beginner
3313: Notes:
3314: If the `Amat` matrix and `Pmat` matrix are different you must call `MatAssemblyBegin()`/`MatAssemblyEnd()` on
3315: each matrix.
3317: If you know the operator `Amat` has a null space you can use `MatSetNullSpace()` and `MatSetTransposeNullSpace()` to supply the null
3318: space to `Amat` and the `KSP` solvers will automatically use that null space as needed during the solution process.
3320: If using `SNESComputeJacobianDefaultColor()` to assemble a Jacobian, the `ctx` argument
3321: must be a `MatFDColoring`.
3323: Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian. One common
3324: example is to use the "Picard linearization" which only differentiates through the highest order parts of each term using `SNESSetPicard()`
3326: .seealso: [](ch_snes), `SNES`, `KSPSetOperators()`, `SNESSetFunction()`, `MatMFFDComputeJacobian()`, `SNESComputeJacobianDefaultColor()`, `MatStructure`,
3327: `SNESSetPicard()`, `SNESJacobianFn`, `SNESFunctionFn`
3328: @*/
3329: PetscErrorCode SNESSetJacobian(SNES snes, Mat Amat, Mat Pmat, SNESJacobianFn *J, PetscCtx ctx)
3330: {
3331: DM dm;
3333: PetscFunctionBegin;
3337: if (Amat) PetscCheckSameComm(snes, 1, Amat, 2);
3338: if (Pmat) PetscCheckSameComm(snes, 1, Pmat, 3);
3339: /* update DMSNES
3340: We support incremental information; so update the function context only if both Amat and Pmat are not specified
3341: (which allows to disable the callbacks when both J and ctx are NULL),
3342: or, if any of the mats is specified, when at least one of J and ctx is not NULL */
3343: PetscCall(SNESGetDM(snes, &dm));
3344: if ((!Amat && !Pmat) || J || ctx) PetscCall(DMSNESSetJacobian(dm, J, ctx));
3345: if (Amat) {
3346: PetscCall(PetscObjectReference((PetscObject)Amat));
3347: PetscCall(MatDestroy(&snes->jacobian));
3349: snes->jacobian = Amat;
3350: }
3351: if (Pmat) {
3352: PetscCall(PetscObjectReference((PetscObject)Pmat));
3353: PetscCall(MatDestroy(&snes->jacobian_pre));
3355: snes->jacobian_pre = Pmat;
3356: }
3357: PetscFunctionReturn(PETSC_SUCCESS);
3358: }
3360: /*@
3361: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
3362: provided context for evaluating the Jacobian.
3364: Not Collective, but `Mat` object will be parallel if `SNES` is
3366: Input Parameter:
3367: . snes - the nonlinear solver context
3369: Output Parameters:
3370: + Amat - location to stash (approximate) Jacobian matrix (or `NULL`)
3371: . Pmat - location to stash matrix used to compute the preconditioner (or `NULL`)
3372: . J - location to put Jacobian function (or `NULL`), for calling sequence see `SNESJacobianFn`
3373: - ctx - location to stash Jacobian ctx (or `NULL`)
3375: Level: advanced
3377: .seealso: [](ch_snes), `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFn`, `SNESGetFunction()`
3378: @*/
3379: PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, PetscCtxRt ctx)
3380: {
3381: DM dm;
3383: PetscFunctionBegin;
3385: if (Amat) *Amat = snes->jacobian;
3386: if (Pmat) *Pmat = snes->jacobian_pre;
3387: PetscCall(SNESGetDM(snes, &dm));
3388: PetscCall(DMSNESGetJacobian(dm, J, ctx));
3389: PetscFunctionReturn(PETSC_SUCCESS);
3390: }
3392: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3393: {
3394: DM dm;
3395: DMSNES sdm;
3397: PetscFunctionBegin;
3398: PetscCall(SNESGetDM(snes, &dm));
3399: PetscCall(DMGetDMSNES(dm, &sdm));
3400: if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3401: DM dm;
3402: PetscBool isdense, ismf;
3404: PetscCall(SNESGetDM(snes, &dm));
3405: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &isdense, MATSEQDENSE, MATMPIDENSE, MATDENSE, NULL));
3406: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &ismf, MATMFFD, MATSHELL, NULL));
3407: if (isdense) PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefault, NULL));
3408: else if (!ismf) PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefaultColor, NULL));
3409: }
3410: PetscFunctionReturn(PETSC_SUCCESS);
3411: }
3413: /*@
3414: SNESSetUp - Sets up the internal data structures for the later use
3415: of a nonlinear solver `SNESSolve()`.
3417: Collective
3419: Input Parameter:
3420: . snes - the `SNES` context
3422: Level: advanced
3424: Note:
3425: For basic use of the `SNES` solvers the user does not need to explicitly call
3426: `SNESSetUp()`, since these actions will automatically occur during
3427: the call to `SNESSolve()`. However, if one wishes to control this
3428: phase separately, `SNESSetUp()` should be called after `SNESCreate()`
3429: and optional routines of the form SNESSetXXX(), but before `SNESSolve()`.
3431: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`, `SNESDestroy()`, `SNESSetFromOptions()`
3432: @*/
3433: PetscErrorCode SNESSetUp(SNES snes)
3434: {
3435: DM dm;
3436: DMSNES sdm;
3437: SNESLineSearch linesearch, pclinesearch;
3438: void *lsprectx, *lspostctx;
3439: PetscBool mf_operator, mf;
3440: Vec f, fpc;
3441: void *funcctx;
3442: void *jacctx, *appctx;
3443: Mat j, jpre;
3444: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, PetscCtx);
3445: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, PetscCtx);
3446: SNESFunctionFn *func;
3447: SNESJacobianFn *jac;
3449: PetscFunctionBegin;
3451: if (snes->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
3452: PetscCall(PetscLogEventBegin(SNES_SetUp, snes, 0, 0, 0));
3454: if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, SNESNEWTONLS));
3456: PetscCall(SNESGetFunction(snes, &snes->vec_func, NULL, NULL));
3458: PetscCall(SNESGetDM(snes, &dm));
3459: PetscCall(DMGetDMSNES(dm, &sdm));
3460: PetscCall(SNESSetDefaultComputeJacobian(snes));
3462: if (!snes->vec_func) PetscCall(DMCreateGlobalVector(dm, &snes->vec_func));
3464: if (snes->usesksp && !snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
3466: if (snes->linesearch) {
3467: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
3468: PetscCall(SNESLineSearchSetFunction(snes->linesearch, SNESComputeFunction));
3469: }
3471: PetscCall(SNESGetUseMatrixFree(snes, &mf_operator, &mf));
3472: if (snes->npc && snes->npcside == PC_LEFT) {
3473: snes->mf = PETSC_TRUE;
3474: snes->mf_operator = PETSC_FALSE;
3475: }
3476: if (snes->ops->ctxcompute && !snes->ctx) PetscCallBack("SNES callback compute application context", (*snes->ops->ctxcompute)(snes, &snes->ctx));
3477: if (snes->mf) PetscCall(SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version));
3479: if (snes->npc) {
3480: SNESNormSchedule npc_norm_schedule;
3482: /* copy the DM over and the functions if NPC DM is not present */
3483: if (!snes->npc->dm) {
3484: PetscCall(SNESGetDM(snes, &dm));
3485: PetscCall(SNESSetDM(snes->npc, dm));
3487: PetscCall(SNESGetFunction(snes, &f, &func, &funcctx));
3488: PetscCall(VecDuplicate(f, &fpc));
3489: PetscCall(SNESSetFunction(snes->npc, fpc, func, funcctx));
3490: PetscCall(SNESGetJacobian(snes, &j, &jpre, &jac, &jacctx));
3491: PetscCall(SNESSetJacobian(snes->npc, j, jpre, jac, jacctx));
3492: PetscCall(SNESSetUseMatrixFree(snes->npc, mf_operator, mf));
3493: PetscCall(VecDestroy(&fpc));
3495: /* copy the function pointers over */
3496: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)snes->npc));
3498: /* Propagate app context if not present */
3499: PetscCall(SNESGetApplicationContext(snes->npc, &appctx));
3500: if (!appctx && !snes->npc->ops->ctxcompute) {
3501: if (snes->ops->ctxcompute) {
3502: PetscCall(SNESSetComputeApplicationContext(snes->npc, snes->ops->ctxcompute, snes->ops->ctxdestroy));
3503: } else {
3504: PetscCall(SNESGetApplicationContext(snes, &appctx));
3505: PetscCall(SNESSetApplicationContext(snes->npc, appctx));
3506: }
3507: }
3508: }
3510: /* Set default norm schedule for NPC if not yet set */
3511: PetscCall(SNESGetNormSchedule(snes->npc, &npc_norm_schedule));
3512: if (npc_norm_schedule == SNES_NORM_DEFAULT) {
3513: if (snes->npcside == PC_RIGHT) PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_FINAL_ONLY));
3514: else if (snes->npcside == PC_LEFT) PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_NONE));
3515: }
3517: PetscCall(SNESSetFromOptions(snes->npc));
3519: /* copy the line search context over */
3520: if (snes->dm == snes->npc->dm && snes->linesearch && snes->npc->linesearch) {
3521: PetscCall(SNESGetLineSearch(snes, &linesearch));
3522: PetscCall(SNESGetLineSearch(snes->npc, &pclinesearch));
3523: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
3524: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
3525: PetscCall(SNESLineSearchSetPreCheck(pclinesearch, precheck, lsprectx));
3526: PetscCall(SNESLineSearchSetPostCheck(pclinesearch, postcheck, lspostctx));
3527: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch));
3528: }
3529: }
3531: snes->jac_iter = 0;
3532: snes->pre_iter = 0;
3534: PetscTryTypeMethod(snes, setup);
3536: PetscCall(SNESSetDefaultComputeJacobian(snes));
3538: if (snes->npc && snes->npcside == PC_LEFT) {
3539: if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3540: if (snes->linesearch) {
3541: PetscCall(SNESGetLineSearch(snes, &linesearch));
3542: PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunctionDefaultNPC));
3543: }
3544: }
3545: }
3546: PetscCall(PetscLogEventEnd(SNES_SetUp, snes, 0, 0, 0));
3547: snes->setupcalled = PETSC_TRUE;
3548: PetscFunctionReturn(PETSC_SUCCESS);
3549: }
3551: /*@
3552: 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
3554: Collective
3556: Input Parameter:
3557: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3559: Level: intermediate
3561: Notes:
3562: Any options set on the `SNES` object, including those set with `SNESSetFromOptions()` remain.
3564: Call this if you wish to reuse a `SNES` but with different size vectors
3566: Also calls the application context destroy routine set with `SNESSetComputeApplicationContext()`
3568: .seealso: [](ch_snes), `SNES`, `SNESDestroy()`, `SNESCreate()`, `SNESSetUp()`, `SNESSolve()`
3569: @*/
3570: PetscErrorCode SNESReset(SNES snes)
3571: {
3572: PetscFunctionBegin;
3574: if (snes->ops->ctxdestroy && snes->ctx) {
3575: PetscCallBack("SNES callback destroy application context", (*snes->ops->ctxdestroy)(&snes->ctx));
3576: snes->ctx = NULL;
3577: }
3578: if (snes->npc) PetscCall(SNESReset(snes->npc));
3580: PetscTryTypeMethod(snes, reset);
3581: if (snes->ksp) PetscCall(KSPReset(snes->ksp));
3583: if (snes->linesearch) PetscCall(SNESLineSearchReset(snes->linesearch));
3585: PetscCall(VecDestroy(&snes->vec_rhs));
3586: PetscCall(VecDestroy(&snes->vec_sol));
3587: PetscCall(VecDestroy(&snes->vec_sol_update));
3588: PetscCall(VecDestroy(&snes->vec_func));
3589: PetscCall(MatDestroy(&snes->jacobian));
3590: PetscCall(MatDestroy(&snes->jacobian_pre));
3591: PetscCall(MatDestroy(&snes->picard));
3592: PetscCall(VecDestroyVecs(snes->nwork, &snes->work));
3593: PetscCall(VecDestroyVecs(snes->nvwork, &snes->vwork));
3595: snes->alwayscomputesfinalresidual = PETSC_FALSE;
3597: snes->nwork = snes->nvwork = 0;
3598: snes->setupcalled = PETSC_FALSE;
3599: PetscFunctionReturn(PETSC_SUCCESS);
3600: }
3602: /*@
3603: SNESConvergedReasonViewCancel - Clears all the reason view functions for a `SNES` object provided with `SNESConvergedReasonViewSet()` also
3604: removes the default viewer.
3606: Collective
3608: Input Parameter:
3609: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3611: Level: intermediate
3613: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESReset()`, `SNESConvergedReasonViewSet()`
3614: @*/
3615: PetscErrorCode SNESConvergedReasonViewCancel(SNES snes)
3616: {
3617: PetscFunctionBegin;
3619: for (PetscInt i = 0; i < snes->numberreasonviews; i++) {
3620: if (snes->reasonviewdestroy[i]) PetscCall((*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]));
3621: }
3622: snes->numberreasonviews = 0;
3623: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
3624: PetscFunctionReturn(PETSC_SUCCESS);
3625: }
3627: /*@
3628: SNESDestroy - Destroys the nonlinear solver context that was created
3629: with `SNESCreate()`.
3631: Collective
3633: Input Parameter:
3634: . snes - the `SNES` context
3636: Level: beginner
3638: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`
3639: @*/
3640: PetscErrorCode SNESDestroy(SNES *snes)
3641: {
3642: DM dm;
3644: PetscFunctionBegin;
3645: if (!*snes) PetscFunctionReturn(PETSC_SUCCESS);
3647: if (--((PetscObject)*snes)->refct > 0) {
3648: *snes = NULL;
3649: PetscFunctionReturn(PETSC_SUCCESS);
3650: }
3652: PetscCall(SNESReset(*snes));
3653: PetscCall(SNESDestroy(&(*snes)->npc));
3655: /* if memory was published with SAWs then destroy it */
3656: PetscCall(PetscObjectSAWsViewOff((PetscObject)*snes));
3657: PetscTryTypeMethod(*snes, destroy);
3659: dm = (*snes)->dm;
3660: while (dm) {
3661: PetscCall(DMCoarsenHookRemove(dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, *snes));
3662: PetscCall(DMGetCoarseDM(dm, &dm));
3663: }
3665: PetscCall(DMDestroy(&(*snes)->dm));
3666: PetscCall(KSPDestroy(&(*snes)->ksp));
3667: PetscCall(SNESLineSearchDestroy(&(*snes)->linesearch));
3669: PetscCall(PetscFree((*snes)->kspconvctx));
3670: if ((*snes)->ops->convergeddestroy) PetscCall((*(*snes)->ops->convergeddestroy)(&(*snes)->cnvP));
3671: if ((*snes)->conv_hist_alloc) PetscCall(PetscFree2((*snes)->conv_hist, (*snes)->conv_hist_its));
3672: PetscCall(SNESMonitorCancel(*snes));
3673: PetscCall(SNESConvergedReasonViewCancel(*snes));
3674: PetscCall(PetscHeaderDestroy(snes));
3675: PetscFunctionReturn(PETSC_SUCCESS);
3676: }
3678: /* ----------- Routines to set solver parameters ---------- */
3680: /*@
3681: SNESSetLagPreconditioner - Sets when the preconditioner is rebuilt in the nonlinear solve `SNESSolve()`.
3683: Logically Collective
3685: Input Parameters:
3686: + snes - the `SNES` context
3687: - lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3688: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3690: Options Database Keys:
3691: + -snes_lag_jacobian_persists (true|false) - sets the persistence through multiple `SNESSolve()`
3692: . -snes_lag_jacobian (-2|1|2|...) - sets the lag
3693: . -snes_lag_preconditioner_persists (true|false) - sets the persistence through multiple `SNESSolve()`
3694: - -snes_lag_preconditioner (-2|1|2|...) - sets the lag
3696: Level: intermediate
3698: Notes:
3699: The default is 1
3701: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagPreconditionerPersists()` was called
3703: `SNESSetLagPreconditionerPersists()` allows using the same uniform lagging (for example every second linear solve) across multiple nonlinear solves.
3705: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetLagPreconditionerPersists()`,
3706: `SNESSetLagJacobianPersists()`, `SNES`, `SNESSolve()`
3707: @*/
3708: PetscErrorCode SNESSetLagPreconditioner(SNES snes, PetscInt lag)
3709: {
3710: PetscFunctionBegin;
3713: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3714: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3715: snes->lagpreconditioner = lag;
3716: PetscFunctionReturn(PETSC_SUCCESS);
3717: }
3719: /*@
3720: SNESSetGridSequence - sets the number of steps of grid sequencing that `SNES` will do
3722: Logically Collective
3724: Input Parameters:
3725: + snes - the `SNES` context
3726: - steps - the number of refinements to do, defaults to 0
3728: Options Database Key:
3729: . -snes_grid_sequence steps - Use grid sequencing to generate initial guess
3731: Level: intermediate
3733: Notes:
3734: Once grid sequencing is turned on `SNESSolve()` will automatically perform the solve on each grid refinement.
3736: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3738: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetGridSequence()`,
3739: `SNESSetDM()`, `SNESSolve()`
3740: @*/
3741: PetscErrorCode SNESSetGridSequence(SNES snes, PetscInt steps)
3742: {
3743: PetscFunctionBegin;
3746: snes->gridsequence = steps;
3747: PetscFunctionReturn(PETSC_SUCCESS);
3748: }
3750: /*@
3751: SNESGetGridSequence - gets the number of steps of grid sequencing that `SNES` will do
3753: Logically Collective
3755: Input Parameter:
3756: . snes - the `SNES` context
3758: Output Parameter:
3759: . steps - the number of refinements to do, defaults to 0
3761: Level: intermediate
3763: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetGridSequence()`
3764: @*/
3765: PetscErrorCode SNESGetGridSequence(SNES snes, PetscInt *steps)
3766: {
3767: PetscFunctionBegin;
3769: *steps = snes->gridsequence;
3770: PetscFunctionReturn(PETSC_SUCCESS);
3771: }
3773: /*@
3774: SNESGetLagPreconditioner - Return how often the preconditioner is rebuilt
3776: Not Collective
3778: Input Parameter:
3779: . snes - the `SNES` context
3781: Output Parameter:
3782: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3783: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3785: Level: intermediate
3787: Notes:
3788: The default is 1
3790: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3792: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3793: @*/
3794: PetscErrorCode SNESGetLagPreconditioner(SNES snes, PetscInt *lag)
3795: {
3796: PetscFunctionBegin;
3798: *lag = snes->lagpreconditioner;
3799: PetscFunctionReturn(PETSC_SUCCESS);
3800: }
3802: /*@
3803: SNESSetLagJacobian - Set when the Jacobian is rebuilt in the nonlinear solve. See `SNESSetLagPreconditioner()` for determining how
3804: often the preconditioner is rebuilt.
3806: Logically Collective
3808: Input Parameters:
3809: + snes - the `SNES` context
3810: - lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3811: the Jacobian is built etc. -2 means rebuild at next chance but then never again
3813: Options Database Keys:
3814: + -snes_lag_jacobian_persists (true|false) - sets the persistence through multiple SNES solves
3815: . -snes_lag_jacobian (-2|1|2|...) - sets the lag
3816: . -snes_lag_preconditioner_persists (true|false) - sets the persistence through multiple SNES solves
3817: - -snes_lag_preconditioner (-2|1|2|...) - sets the lag.
3819: Level: intermediate
3821: Notes:
3822: The default is 1
3824: The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3826: 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
3827: at the next Newton step but never again (unless it is reset to another value)
3829: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagPreconditioner()`, `SNESGetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3830: @*/
3831: PetscErrorCode SNESSetLagJacobian(SNES snes, PetscInt lag)
3832: {
3833: PetscFunctionBegin;
3835: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3836: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3838: snes->lagjacobian = lag;
3839: PetscFunctionReturn(PETSC_SUCCESS);
3840: }
3842: /*@
3843: SNESGetLagJacobian - Get how often the Jacobian is rebuilt. See `SNESGetLagPreconditioner()` to determine when the preconditioner is rebuilt
3845: Not Collective
3847: Input Parameter:
3848: . snes - the `SNES` context
3850: Output Parameter:
3851: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3852: the Jacobian is built etc.
3854: Level: intermediate
3856: Notes:
3857: The default is 1
3859: The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagJacobianPersists()` was called.
3861: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobian()`, `SNESSetLagPreconditioner()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3862: @*/
3863: PetscErrorCode SNESGetLagJacobian(SNES snes, PetscInt *lag)
3864: {
3865: PetscFunctionBegin;
3867: *lag = snes->lagjacobian;
3868: PetscFunctionReturn(PETSC_SUCCESS);
3869: }
3871: /*@
3872: SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple nonlinear solves
3874: Logically collective
3876: Input Parameters:
3877: + snes - the `SNES` context
3878: - flg - jacobian lagging persists if true
3880: Options Database Keys:
3881: + -snes_lag_jacobian_persists (true|false) - sets the persistence through multiple SNES solves
3882: . -snes_lag_jacobian (-2|1|2|...) - sets the lag
3883: . -snes_lag_preconditioner_persists (true|false) - sets the persistence through multiple SNES solves
3884: - -snes_lag_preconditioner (-2|1|2|...) - sets the lag
3886: Level: advanced
3888: Notes:
3889: Normally when `SNESSetLagJacobian()` is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3891: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3892: several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3893: timesteps may present huge efficiency gains.
3895: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditionerPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`
3896: @*/
3897: PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
3898: {
3899: PetscFunctionBegin;
3902: snes->lagjac_persist = flg;
3903: PetscFunctionReturn(PETSC_SUCCESS);
3904: }
3906: /*@
3907: SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves
3909: Logically Collective
3911: Input Parameters:
3912: + snes - the `SNES` context
3913: - flg - preconditioner lagging persists if true
3915: Options Database Keys:
3916: + -snes_lag_jacobian_persists (true|false) - sets the persistence through multiple SNES solves
3917: . -snes_lag_jacobian (-2|1|2|...) - sets the lag
3918: . -snes_lag_preconditioner_persists (true|false) - sets the persistence through multiple SNES solves
3919: - -snes_lag_preconditioner (-2|1|2|...) - sets the lag
3921: Level: developer
3923: Notes:
3924: Normally when `SNESSetLagPreconditioner()` is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3926: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3927: by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3928: several timesteps may present huge efficiency gains.
3930: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobianPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagPreconditioner()`
3931: @*/
3932: PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)
3933: {
3934: PetscFunctionBegin;
3937: snes->lagpre_persist = flg;
3938: PetscFunctionReturn(PETSC_SUCCESS);
3939: }
3941: /*@
3942: SNESSetForceIteration - force `SNESSolve()` to take at least one iteration regardless of the initial residual norm
3944: Logically Collective
3946: Input Parameters:
3947: + snes - the `SNES` context
3948: - force - `PETSC_TRUE` require at least one iteration
3950: Options Database Key:
3951: . -snes_force_iteration force - Sets forcing an iteration
3953: Level: intermediate
3955: Note:
3956: This is used sometimes with `TS` to prevent `TS` from detecting a false steady state solution
3958: .seealso: [](ch_snes), `SNES`, `TS`, `SNESSetDivergenceTolerance()`
3959: @*/
3960: PetscErrorCode SNESSetForceIteration(SNES snes, PetscBool force)
3961: {
3962: PetscFunctionBegin;
3964: snes->forceiteration = force;
3965: PetscFunctionReturn(PETSC_SUCCESS);
3966: }
3968: /*@
3969: SNESGetForceIteration - Check whether or not `SNESSolve()` take at least one iteration regardless of the initial residual norm
3971: Logically Collective
3973: Input Parameter:
3974: . snes - the `SNES` context
3976: Output Parameter:
3977: . force - `PETSC_TRUE` requires at least one iteration.
3979: Level: intermediate
3981: .seealso: [](ch_snes), `SNES`, `SNESSetForceIteration()`, `SNESSetDivergenceTolerance()`
3982: @*/
3983: PetscErrorCode SNESGetForceIteration(SNES snes, PetscBool *force)
3984: {
3985: PetscFunctionBegin;
3987: *force = snes->forceiteration;
3988: PetscFunctionReturn(PETSC_SUCCESS);
3989: }
3991: /*@
3992: SNESSetTolerances - Sets various parameters used in `SNES` convergence tests.
3994: Logically Collective
3996: Input Parameters:
3997: + snes - the `SNES` context
3998: . abstol - the absolute convergence tolerance, $ F(x^n) \le abstol $
3999: . rtol - the relative convergence tolerance, $ F(x^n) \le reltol * F(x^0) $
4000: . stol - convergence tolerance in terms of the norm of the change in the solution between steps, || delta x || < stol*|| x ||
4001: . maxit - the maximum number of iterations allowed in the solver, default 50.
4002: - maxf - the maximum number of function evaluations allowed in the solver (use `PETSC_UNLIMITED` indicates no limit), default 10,000
4004: Options Database Keys:
4005: + -snes_atol abstol - Sets `abstol`
4006: . -snes_rtol rtol - Sets `rtol`
4007: . -snes_stol stol - Sets `stol`
4008: . -snes_max_it maxit - Sets `maxit`
4009: - -snes_max_funcs maxf - Sets `maxf` (use `unlimited` to have no maximum)
4011: Level: intermediate
4013: Note:
4014: All parameters must be non-negative
4016: Use `PETSC_CURRENT` to retain the current value of any parameter and `PETSC_DETERMINE` to use the default value for the given `SNES`.
4017: The default value is the value in the object when its type is set.
4019: Use `PETSC_UNLIMITED` on `maxit` or `maxf` to indicate there is no bound on the number of iterations or number of function evaluations.
4021: Fortran Note:
4022: Use `PETSC_CURRENT_INTEGER`, `PETSC_CURRENT_REAL`, `PETSC_UNLIMITED_INTEGER`, `PETSC_DETERMINE_INTEGER`, or `PETSC_DETERMINE_REAL`
4024: .seealso: [](ch_snes), `SNESSolve()`, `SNES`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`
4025: @*/
4026: PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
4027: {
4028: PetscFunctionBegin;
4036: if (abstol == (PetscReal)PETSC_DETERMINE) {
4037: snes->abstol = snes->default_abstol;
4038: } else if (abstol != (PetscReal)PETSC_CURRENT) {
4039: PetscCheck(abstol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %g must be non-negative", (double)abstol);
4040: snes->abstol = abstol;
4041: }
4043: if (rtol == (PetscReal)PETSC_DETERMINE) {
4044: snes->rtol = snes->default_rtol;
4045: } else if (rtol != (PetscReal)PETSC_CURRENT) {
4046: 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);
4047: snes->rtol = rtol;
4048: }
4050: if (stol == (PetscReal)PETSC_DETERMINE) {
4051: snes->stol = snes->default_stol;
4052: } else if (stol != (PetscReal)PETSC_CURRENT) {
4053: PetscCheck(stol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Step tolerance %g must be non-negative", (double)stol);
4054: snes->stol = stol;
4055: }
4057: if (maxit == PETSC_DETERMINE) {
4058: snes->max_its = snes->default_max_its;
4059: } else if (maxit == PETSC_UNLIMITED) {
4060: snes->max_its = PETSC_INT_MAX;
4061: } else if (maxit != PETSC_CURRENT) {
4062: PetscCheck(maxit >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", maxit);
4063: snes->max_its = maxit;
4064: }
4066: if (maxf == PETSC_DETERMINE) {
4067: snes->max_funcs = snes->default_max_funcs;
4068: } else if (maxf == PETSC_UNLIMITED || maxf == -1) {
4069: snes->max_funcs = PETSC_UNLIMITED;
4070: } else if (maxf != PETSC_CURRENT) {
4071: PetscCheck(maxf >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of function evaluations %" PetscInt_FMT " must be nonnegative", maxf);
4072: snes->max_funcs = maxf;
4073: }
4074: PetscFunctionReturn(PETSC_SUCCESS);
4075: }
4077: /*@
4078: SNESSetDivergenceTolerance - Sets the divergence tolerance used for the `SNES` divergence test.
4080: Logically Collective
4082: Input Parameters:
4083: + snes - the `SNES` context
4084: - 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
4085: is stopped due to divergence.
4087: Options Database Key:
4088: . -snes_divergence_tolerance divtol - Sets `divtol`
4090: Level: intermediate
4092: Notes:
4093: Use `PETSC_DETERMINE` to use the default value from when the object's type was set.
4095: Fortran Note:
4096: Use ``PETSC_DETERMINE_REAL` or `PETSC_UNLIMITED_REAL`
4098: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetTolerances()`, `SNESGetDivergenceTolerance()`
4099: @*/
4100: PetscErrorCode SNESSetDivergenceTolerance(SNES snes, PetscReal divtol)
4101: {
4102: PetscFunctionBegin;
4106: if (divtol == (PetscReal)PETSC_DETERMINE) {
4107: snes->divtol = snes->default_divtol;
4108: } else if (divtol == (PetscReal)PETSC_UNLIMITED || divtol == -1) {
4109: snes->divtol = PETSC_UNLIMITED;
4110: } else if (divtol != (PetscReal)PETSC_CURRENT) {
4111: PetscCheck(divtol >= 1.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Divergence tolerance %g must be greater than 1.0", (double)divtol);
4112: snes->divtol = divtol;
4113: }
4114: PetscFunctionReturn(PETSC_SUCCESS);
4115: }
4117: /*@
4118: SNESGetTolerances - Gets various parameters used in `SNES` convergence tests.
4120: Not Collective
4122: Input Parameter:
4123: . snes - the `SNES` context
4125: Output Parameters:
4126: + atol - the absolute convergence tolerance
4127: . rtol - the relative convergence tolerance
4128: . stol - convergence tolerance in terms of the norm of the change in the solution between steps
4129: . maxit - the maximum number of iterations allowed
4130: - maxf - the maximum number of function evaluations allowed, `PETSC_UNLIMITED` indicates no bound
4132: Level: intermediate
4134: Notes:
4135: See `SNESSetTolerances()` for details on the parameters.
4137: The user can specify `NULL` for any parameter that is not needed.
4139: .seealso: [](ch_snes), `SNES`, `SNESSetTolerances()`
4140: @*/
4141: PetscErrorCode SNESGetTolerances(SNES snes, PetscReal *atol, PetscReal *rtol, PetscReal *stol, PetscInt *maxit, PetscInt *maxf)
4142: {
4143: PetscFunctionBegin;
4145: if (atol) *atol = snes->abstol;
4146: if (rtol) *rtol = snes->rtol;
4147: if (stol) *stol = snes->stol;
4148: if (maxit) *maxit = snes->max_its;
4149: if (maxf) *maxf = snes->max_funcs;
4150: PetscFunctionReturn(PETSC_SUCCESS);
4151: }
4153: /*@
4154: SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.
4156: Not Collective
4158: Input Parameters:
4159: + snes - the `SNES` context
4160: - divtol - divergence tolerance
4162: Level: intermediate
4164: .seealso: [](ch_snes), `SNES`, `SNESSetDivergenceTolerance()`
4165: @*/
4166: PetscErrorCode SNESGetDivergenceTolerance(SNES snes, PetscReal *divtol)
4167: {
4168: PetscFunctionBegin;
4170: if (divtol) *divtol = snes->divtol;
4171: PetscFunctionReturn(PETSC_SUCCESS);
4172: }
4174: PETSC_INTERN PetscErrorCode SNESMonitorRange_Private(SNES, PetscInt, PetscReal *);
4176: /*@
4177: SNESMonitorLGRange - Line-graph monitor that plots the residual norm together with residual-range statistics for a `SNESSolve()`
4179: Collective
4181: Input Parameters:
4182: + snes - the `SNES` context
4183: . n - the iteration number
4184: . rnorm - the 2-norm of the residual
4185: - monctx - a `PetscViewer` of type `PETSCVIEWERDRAW` set up with `PetscViewerMonitorLGSetUp()`
4187: Level: intermediate
4189: Note:
4190: Plots four line graphs in the viewer: the residual norm (log scale), the fraction of residual entries larger than 20% of the maximum entry, the relative decrease `(prev - rnorm)/prev`, and their product.
4192: .seealso: [](ch_snes), `SNES`, `SNESMonitorSet()`, `SNESMonitorDefault()`, `PetscViewerDrawGetDrawLG()`, `PetscDrawLG`
4193: @*/
4194: PetscErrorCode SNESMonitorLGRange(SNES snes, PetscInt n, PetscReal rnorm, PetscCtx monctx)
4195: {
4196: PetscDrawLG lg;
4197: PetscReal x, y, per;
4198: PetscViewer v = (PetscViewer)monctx;
4199: static PetscReal prev; /* should be in the context */
4200: PetscDraw draw;
4202: PetscFunctionBegin;
4204: PetscCall(PetscViewerDrawGetDrawLG(v, 0, &lg));
4205: if (!n) PetscCall(PetscDrawLGReset(lg));
4206: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4207: PetscCall(PetscDrawSetTitle(draw, "Residual norm"));
4208: x = (PetscReal)n;
4209: if (rnorm > 0.0) y = PetscLog10Real(rnorm);
4210: else y = -15.0;
4211: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4212: if (n < 20 || !(n % 5) || snes->reason) {
4213: PetscCall(PetscDrawLGDraw(lg));
4214: PetscCall(PetscDrawLGSave(lg));
4215: }
4217: PetscCall(PetscViewerDrawGetDrawLG(v, 1, &lg));
4218: if (!n) PetscCall(PetscDrawLGReset(lg));
4219: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4220: PetscCall(PetscDrawSetTitle(draw, "% elements > .2*max element"));
4221: PetscCall(SNESMonitorRange_Private(snes, n, &per));
4222: x = (PetscReal)n;
4223: y = 100.0 * per;
4224: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4225: if (n < 20 || !(n % 5) || snes->reason) {
4226: PetscCall(PetscDrawLGDraw(lg));
4227: PetscCall(PetscDrawLGSave(lg));
4228: }
4230: PetscCall(PetscViewerDrawGetDrawLG(v, 2, &lg));
4231: if (!n) {
4232: prev = rnorm;
4233: PetscCall(PetscDrawLGReset(lg));
4234: }
4235: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4236: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm"));
4237: x = (PetscReal)n;
4238: y = (prev - rnorm) / prev;
4239: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4240: if (n < 20 || !(n % 5) || snes->reason) {
4241: PetscCall(PetscDrawLGDraw(lg));
4242: PetscCall(PetscDrawLGSave(lg));
4243: }
4245: PetscCall(PetscViewerDrawGetDrawLG(v, 3, &lg));
4246: if (!n) PetscCall(PetscDrawLGReset(lg));
4247: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4248: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm*(% > .2 max)"));
4249: x = (PetscReal)n;
4250: y = (prev - rnorm) / (prev * per);
4251: if (n > 2) { /*skip initial crazy value */
4252: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4253: }
4254: if (n < 20 || !(n % 5) || snes->reason) {
4255: PetscCall(PetscDrawLGDraw(lg));
4256: PetscCall(PetscDrawLGSave(lg));
4257: }
4258: prev = rnorm;
4259: PetscFunctionReturn(PETSC_SUCCESS);
4260: }
4262: /*@
4263: SNESConverged - Run the convergence test and update the `SNESConvergedReason`.
4265: Collective
4267: Input Parameters:
4268: + snes - the `SNES` context
4269: . it - current iteration
4270: . xnorm - 2-norm of current iterate
4271: . snorm - 2-norm of current step
4272: - fnorm - 2-norm of function
4274: Level: developer
4276: Note:
4277: This routine is called by the `SNESSolve()` implementations.
4278: It does not typically need to be called by the user.
4280: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4281: @*/
4282: PetscErrorCode SNESConverged(SNES snes, PetscInt it, PetscReal xnorm, PetscReal snorm, PetscReal fnorm)
4283: {
4284: PetscFunctionBegin;
4285: if (!snes->reason) {
4286: if (snes->normschedule == SNES_NORM_ALWAYS) PetscUseTypeMethod(snes, converged, it, xnorm, snorm, fnorm, &snes->reason, snes->cnvP);
4287: if (it == snes->max_its && !snes->reason) {
4288: if (snes->normschedule == SNES_NORM_ALWAYS) {
4289: PetscCall(PetscInfo(snes, "Maximum number of iterations has been reached: %" PetscInt_FMT "\n", snes->max_its));
4290: snes->reason = SNES_DIVERGED_MAX_IT;
4291: } else snes->reason = SNES_CONVERGED_ITS;
4292: }
4293: }
4294: PetscFunctionReturn(PETSC_SUCCESS);
4295: }
4297: /*@
4298: SNESMonitor - runs any `SNES` monitor routines provided with `SNESMonitor()` or the options database
4300: Collective
4302: Input Parameters:
4303: + snes - nonlinear solver context obtained from `SNESCreate()`
4304: . iter - current iteration number
4305: - rnorm - current relative norm of the residual
4307: Level: developer
4309: Note:
4310: This routine is called by the `SNESSolve()` implementations.
4311: It does not typically need to be called by the user.
4313: .seealso: [](ch_snes), `SNES`, `SNESMonitorSet()`
4314: @*/
4315: PetscErrorCode SNESMonitor(SNES snes, PetscInt iter, PetscReal rnorm)
4316: {
4317: PetscInt i, n = snes->numbermonitors;
4319: PetscFunctionBegin;
4320: PetscCall(VecLockReadPush(snes->vec_sol));
4321: for (i = 0; i < n; i++) PetscCall((*snes->monitor[i])(snes, iter, rnorm, snes->monitorcontext[i]));
4322: PetscCall(VecLockReadPop(snes->vec_sol));
4323: PetscFunctionReturn(PETSC_SUCCESS);
4324: }
4326: /* ------------ Routines to set performance monitoring options ----------- */
4328: /*MC
4329: SNESMonitorFunction - functional form passed to `SNESMonitorSet()` to monitor convergence of nonlinear solver
4331: Synopsis:
4332: #include <petscsnes.h>
4333: PetscErrorCode SNESMonitorFunction(SNES snes, PetscInt its, PetscReal norm, PetscCtx mctx)
4335: Collective
4337: Input Parameters:
4338: + snes - the `SNES` context
4339: . its - iteration number
4340: . norm - 2-norm function value (may be estimated)
4341: - mctx - [optional] monitoring context
4343: Level: advanced
4345: .seealso: [](ch_snes), `SNESMonitorSet()`, `PetscCtx`
4346: M*/
4348: /*@
4349: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
4350: iteration of the `SNES` nonlinear solver to display the iteration's
4351: progress.
4353: Logically Collective
4355: Input Parameters:
4356: + snes - the `SNES` context
4357: . f - the monitor function, for the calling sequence see `SNESMonitorFunction`
4358: . mctx - [optional] user-defined context for private data for the monitor routine (use `NULL` if no context is desired)
4359: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4361: Calling sequence of f:
4362: + snes - the `SNES` object
4363: . it - the current iteration
4364: . rnorm - norm of the residual
4365: - mctx - the optional monitor context
4367: Options Database Keys:
4368: + -snes_monitor - sets `SNESMonitorDefault()`
4369: . -snes_monitor draw::draw_lg - sets line graph monitor
4370: - -snes_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `SNESMonitorSet()`, but does not cancel those set via
4371: the options database.
4373: Level: intermediate
4375: Note:
4376: Several different monitoring routines may be set by calling
4377: `SNESMonitorSet()` multiple times; all will be called in the
4378: order in which they were set.
4380: Fortran Note:
4381: Only a single monitor function can be set for each `SNES` object
4383: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESMonitorDefault()`, `SNESMonitorCancel()`, `SNESMonitorFunction`, `PetscCtxDestroyFn`
4384: @*/
4385: PetscErrorCode SNESMonitorSet(SNES snes, PetscErrorCode (*f)(SNES snes, PetscInt it, PetscReal rnorm, PetscCtx mctx), PetscCtx mctx, PetscCtxDestroyFn *monitordestroy)
4386: {
4387: PetscFunctionBegin;
4389: for (PetscInt i = 0; i < snes->numbermonitors; i++) {
4390: PetscBool identical;
4392: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))(PetscVoidFn *)f, mctx, monitordestroy, (PetscErrorCode (*)(void))(PetscVoidFn *)snes->monitor[i], snes->monitorcontext[i], snes->monitordestroy[i], &identical));
4393: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4394: }
4395: PetscCheck(snes->numbermonitors < MAXSNESMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
4396: snes->monitor[snes->numbermonitors] = f;
4397: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
4398: snes->monitorcontext[snes->numbermonitors++] = mctx;
4399: PetscFunctionReturn(PETSC_SUCCESS);
4400: }
4402: /*@
4403: SNESMonitorCancel - Clears all the monitor functions for a `SNES` object.
4405: Logically Collective
4407: Input Parameter:
4408: . snes - the `SNES` context
4410: Options Database Key:
4411: . -snes_monitor_cancel - cancels all monitors that have been hardwired
4412: into a code by calls to `SNESMonitorSet()`, but does not cancel those
4413: set via the options database
4415: Level: intermediate
4417: Note:
4418: There is no way to clear one specific monitor from a `SNES` object.
4420: .seealso: [](ch_snes), `SNES`, `SNESMonitorDefault()`, `SNESMonitorSet()`
4421: @*/
4422: PetscErrorCode SNESMonitorCancel(SNES snes)
4423: {
4424: PetscFunctionBegin;
4426: for (PetscInt i = 0; i < snes->numbermonitors; i++) {
4427: if (snes->monitordestroy[i]) PetscCall((*snes->monitordestroy[i])(&snes->monitorcontext[i]));
4428: }
4429: snes->numbermonitors = 0;
4430: PetscFunctionReturn(PETSC_SUCCESS);
4431: }
4433: /*@
4434: SNESSetConvergenceTest - Sets the function that is to be used
4435: to test for convergence of the nonlinear iterative solution.
4437: Logically Collective
4439: Input Parameters:
4440: + snes - the `SNES` context
4441: . func - routine to test for convergence
4442: . ctx - [optional] context for private data for the convergence routine (may be `NULL`)
4443: - destroy - [optional] destructor for the context (may be `NULL`; `PETSC_NULL_FUNCTION` in Fortran)
4445: Calling sequence of func:
4446: + snes - the `SNES` context
4447: . it - the current iteration number
4448: . xnorm - the norm of the new solution
4449: . snorm - the norm of the step
4450: . fnorm - the norm of the function value
4451: . reason - output, the reason convergence or divergence as declared
4452: - ctx - the optional convergence test context
4454: Level: advanced
4456: .seealso: [](ch_snes), `SNES`, `SNESConvergedDefault()`, `SNESConvergedSkip()`
4457: @*/
4458: PetscErrorCode SNESSetConvergenceTest(SNES snes, PetscErrorCode (*func)(SNES snes, PetscInt it, PetscReal xnorm, PetscReal snorm, PetscReal fnorm, SNESConvergedReason *reason, PetscCtx ctx), PetscCtx ctx, PetscCtxDestroyFn *destroy)
4459: {
4460: PetscFunctionBegin;
4462: if (!func) func = SNESConvergedSkip;
4463: if (snes->ops->convergeddestroy) PetscCall((*snes->ops->convergeddestroy)(&snes->cnvP));
4464: snes->ops->converged = func;
4465: snes->ops->convergeddestroy = destroy;
4466: snes->cnvP = ctx;
4467: PetscFunctionReturn(PETSC_SUCCESS);
4468: }
4470: /*@
4471: SNESGetConvergedReason - Gets the reason the `SNES` iteration was stopped, which may be due to convergence, divergence, or stagnation
4473: Not Collective
4475: Input Parameter:
4476: . snes - the `SNES` context
4478: Output Parameter:
4479: . reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` for the individual convergence tests for complete lists
4481: Options Database Key:
4482: . -snes_converged_reason - prints the reason to standard out
4484: Level: intermediate
4486: Note:
4487: Should only be called after the call the `SNESSolve()` is complete, if it is called earlier it returns the value `SNES__CONVERGED_ITERATING`.
4489: .seealso: [](ch_snes), `SNESSolve()`, `SNESSetConvergenceTest()`, `SNESSetConvergedReason()`, `SNESConvergedReason`, `SNESGetConvergedReasonString()`
4490: @*/
4491: PetscErrorCode SNESGetConvergedReason(SNES snes, SNESConvergedReason *reason)
4492: {
4493: PetscFunctionBegin;
4495: PetscAssertPointer(reason, 2);
4496: *reason = snes->reason;
4497: PetscFunctionReturn(PETSC_SUCCESS);
4498: }
4500: /*@
4501: SNESGetConvergedReasonString - Return a human readable string for `SNESConvergedReason`
4503: Not Collective
4505: Input Parameter:
4506: . snes - the `SNES` context
4508: Output Parameter:
4509: . strreason - a human readable string that describes `SNES` converged reason
4511: Level: beginner
4513: .seealso: [](ch_snes), `SNES`, `SNESGetConvergedReason()`
4514: @*/
4515: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char *strreason[])
4516: {
4517: PetscFunctionBegin;
4519: PetscAssertPointer(strreason, 2);
4520: *strreason = SNESConvergedReasons[snes->reason];
4521: PetscFunctionReturn(PETSC_SUCCESS);
4522: }
4524: /*@
4525: SNESSetConvergedReason - Sets the reason the `SNES` iteration was stopped.
4527: Not Collective
4529: Input Parameters:
4530: + snes - the `SNES` context
4531: - reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` or the
4532: manual pages for the individual convergence tests for complete lists
4534: Level: developer
4536: Developer Note:
4537: Called inside the various `SNESSolve()` implementations
4539: .seealso: [](ch_snes), `SNESGetConvergedReason()`, `SNESSetConvergenceTest()`, `SNESConvergedReason`
4540: @*/
4541: PetscErrorCode SNESSetConvergedReason(SNES snes, SNESConvergedReason reason)
4542: {
4543: PetscFunctionBegin;
4545: PetscCheck(!snes->errorifnotconverged || reason > 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_PLIB, "SNES code should have previously errored due to negative reason");
4546: snes->reason = reason;
4547: PetscFunctionReturn(PETSC_SUCCESS);
4548: }
4550: /*@
4551: SNESSetConvergenceHistory - Sets the arrays used to hold the convergence history.
4553: Logically Collective
4555: Input Parameters:
4556: + snes - iterative context obtained from `SNESCreate()`
4557: . a - array to hold history, this array will contain the function norms computed at each step
4558: . its - integer array holds the number of linear iterations for each solve.
4559: . na - size of `a` and `its`
4560: - reset - `PETSC_TRUE` indicates each new nonlinear solve resets the history counter to zero,
4561: else it continues storing new values for new nonlinear solves after the old ones
4563: Level: intermediate
4565: Notes:
4566: If 'a' and 'its' are `NULL` then space is allocated for the history. If 'na' is `PETSC_DECIDE` (or, deprecated, `PETSC_DEFAULT`) then a
4567: default array of length 1,000 is allocated.
4569: This routine is useful, e.g., when running a code for purposes
4570: of accurate performance monitoring, when no I/O should be done
4571: during the section of code that is being timed.
4573: If the arrays run out of space after a number of iterations then the later values are not saved in the history
4575: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergenceHistory()`
4576: @*/
4577: PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)
4578: {
4579: PetscFunctionBegin;
4581: if (a) PetscAssertPointer(a, 2);
4582: if (its) PetscAssertPointer(its, 3);
4583: if (!a) {
4584: if (na == PETSC_DECIDE) na = 1000;
4585: PetscCall(PetscCalloc2(na, &a, na, &its));
4586: snes->conv_hist_alloc = PETSC_TRUE;
4587: }
4588: snes->conv_hist = a;
4589: snes->conv_hist_its = its;
4590: snes->conv_hist_max = (size_t)na;
4591: snes->conv_hist_len = 0;
4592: snes->conv_hist_reset = reset;
4593: PetscFunctionReturn(PETSC_SUCCESS);
4594: }
4596: #if PetscDefined(HAVE_MATLAB)
4597: #include <engine.h> /* MATLAB include file */
4598: #include <mex.h> /* MATLAB include file */
4600: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4601: {
4602: mxArray *mat;
4603: PetscReal *ar;
4605: mat = mxCreateDoubleMatrix(snes->conv_hist_len, 1, mxREAL);
4606: ar = (PetscReal *)mxGetData(mat);
4607: for (PetscInt i = 0; i < snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4608: return mat;
4609: }
4610: #endif
4612: /*@
4613: SNESGetConvergenceHistory - Gets the arrays used to hold the convergence history.
4615: Not Collective
4617: Input Parameter:
4618: . snes - iterative context obtained from `SNESCreate()`
4620: Output Parameters:
4621: + a - array to hold history, usually was set with `SNESSetConvergenceHistory()`
4622: . its - integer array holds the number of linear iterations (or
4623: negative if not converged) for each solve.
4624: - na - size of `a` and `its`
4626: Level: intermediate
4628: Note:
4629: This routine is useful, e.g., when running a code for purposes
4630: of accurate performance monitoring, when no I/O should be done
4631: during the section of code that is being timed.
4633: Fortran Notes:
4634: Return the arrays with ``SNESRestoreConvergenceHistory()`
4636: Use the arguments
4637: .vb
4638: PetscReal, pointer :: a(:)
4639: PetscInt, pointer :: its(:)
4640: .ve
4642: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetConvergenceHistory()`
4643: @*/
4644: PetscErrorCode SNESGetConvergenceHistory(SNES snes, PetscReal *a[], PetscInt *its[], PetscInt *na)
4645: {
4646: PetscFunctionBegin;
4648: if (a) *a = snes->conv_hist;
4649: if (its) *its = snes->conv_hist_its;
4650: if (na) *na = (PetscInt)snes->conv_hist_len;
4651: PetscFunctionReturn(PETSC_SUCCESS);
4652: }
4654: /*@
4655: SNESSetUpdate - Sets the general-purpose update function called
4656: at the beginning of every iteration of the nonlinear solve. Specifically
4657: it is called just before the Jacobian is "evaluated" and after the function
4658: evaluation.
4660: Logically Collective
4662: Input Parameters:
4663: + snes - The nonlinear solver context
4664: - func - The update function; for calling sequence see `SNESUpdateFn`
4666: Level: advanced
4668: Notes:
4669: 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
4670: to `SNESSetFunction()`, or `SNESSetPicard()`
4671: This is not used by most users, and it is intended to provide a general hook that is run
4672: right before the direction step is computed.
4674: Users are free to modify the current residual vector,
4675: the current linearization point, or any other vector associated to the specific solver used.
4676: If such modifications take place, it is the user responsibility to update all the relevant
4677: vectors. For example, if one is adjusting the model parameters at each Newton step their code may look like
4678: .vb
4679: PetscErrorCode update(SNES snes, PetscInt iteration)
4680: {
4681: PetscFunctionBeginUser;
4682: if (iteration > 0) {
4683: // update the model parameters here
4684: Vec x,f;
4685: PetscCall(SNESGetSolution(snes,&x));
4686: PetcCall(SNESGetFunction(snes,&f,NULL,NULL));
4687: PetscCall(SNESComputeFunction(snes,x,f));
4688: }
4689: PetscFunctionReturn(PETSC_SUCCESS);
4690: }
4691: .ve
4693: 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.
4695: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetJacobian()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRSetPostCheck()`,
4696: `SNESMonitorSet()`
4697: @*/
4698: PetscErrorCode SNESSetUpdate(SNES snes, SNESUpdateFn *func)
4699: {
4700: PetscFunctionBegin;
4702: snes->ops->update = func;
4703: PetscFunctionReturn(PETSC_SUCCESS);
4704: }
4706: /*@
4707: SNESConvergedReasonView - Displays the reason a `SNES` solve converged or diverged to a viewer
4709: Collective
4711: Input Parameters:
4712: + snes - iterative context obtained from `SNESCreate()`
4713: - viewer - the viewer to display the reason
4715: Options Database Keys:
4716: + -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4717: - -snes_converged_reason ::failed - only print reason and number of iterations when diverged
4719: Level: beginner
4721: Note:
4722: To change the format of the output call `PetscViewerPushFormat`(viewer,format) before this call. Use `PETSC_VIEWER_DEFAULT` for the default,
4723: use `PETSC_VIEWER_FAILED` to only display a reason if it fails.
4725: .seealso: [](ch_snes), `SNESConvergedReason`, `PetscViewer`, `SNES`,
4726: `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`, `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`,
4727: `SNESConvergedReasonViewFromOptions()`,
4728: `PetscViewerPushFormat()`, `PetscViewerPopFormat()`
4729: @*/
4730: PetscErrorCode SNESConvergedReasonView(SNES snes, PetscViewer viewer)
4731: {
4732: PetscViewerFormat format;
4733: PetscBool isAscii;
4735: PetscFunctionBegin;
4736: if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4737: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isAscii));
4738: if (isAscii) {
4739: PetscCall(PetscViewerGetFormat(viewer, &format));
4740: PetscCall(PetscViewerASCIIAddTab(viewer, ((PetscObject)snes)->tablevel + 1));
4741: if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4742: DM dm;
4743: Vec u;
4744: PetscDS prob;
4745: PetscInt Nf;
4746: PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4747: void **exactCtx;
4748: PetscReal error;
4750: PetscCall(SNESGetDM(snes, &dm));
4751: PetscCall(SNESGetSolution(snes, &u));
4752: PetscCall(DMGetDS(dm, &prob));
4753: PetscCall(PetscDSGetNumFields(prob, &Nf));
4754: PetscCall(PetscMalloc2(Nf, &exactSol, Nf, &exactCtx));
4755: for (PetscInt f = 0; f < Nf; ++f) PetscCall(PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]));
4756: PetscCall(DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error));
4757: PetscCall(PetscFree2(exactSol, exactCtx));
4758: if (error < 1.0e-11) PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n"));
4759: else PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", (double)error));
4760: }
4761: if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4762: if (((PetscObject)snes)->prefix) {
4763: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve converged due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4764: } else {
4765: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve converged due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4766: }
4767: } else if (snes->reason <= 0) {
4768: if (((PetscObject)snes)->prefix) {
4769: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve did not converge due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4770: } else {
4771: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve did not converge due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4772: }
4773: }
4774: PetscCall(PetscViewerASCIISubtractTab(viewer, ((PetscObject)snes)->tablevel + 1));
4775: }
4776: PetscFunctionReturn(PETSC_SUCCESS);
4777: }
4779: /*@
4780: SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4781: end of the nonlinear solver to display the convergence reason of the nonlinear solver.
4783: Logically Collective
4785: Input Parameters:
4786: + snes - the `SNES` context
4787: . f - the `SNESConvergedReason` view function
4788: . vctx - [optional] user-defined context for private data for the `SNESConvergedReason` view function (use `NULL` if no context is desired)
4789: - reasonviewdestroy - [optional] routine that frees the context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4791: Calling sequence of `f`:
4792: + snes - the `SNES` context
4793: - vctx - [optional] context for private data for the function
4795: Options Database Keys:
4796: + -snes_converged_reason - sets a default `SNESConvergedReasonView()`
4797: - -snes_converged_reason_view_cancel - cancels all converged reason viewers that have been hardwired into a code by
4798: calls to `SNESConvergedReasonViewSet()`, but does not cancel those set via the options database.
4800: Level: intermediate
4802: Note:
4803: Several different converged reason view routines may be set by calling
4804: `SNESConvergedReasonViewSet()` multiple times; all will be called in the
4805: order in which they were set.
4807: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESConvergedReason`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`, `SNESConvergedReasonViewCancel()`,
4808: `PetscCtxDestroyFn`
4809: @*/
4810: PetscErrorCode SNESConvergedReasonViewSet(SNES snes, PetscErrorCode (*f)(SNES snes, PetscCtx vctx), PetscCtx vctx, PetscCtxDestroyFn *reasonviewdestroy)
4811: {
4812: PetscFunctionBegin;
4814: for (PetscInt i = 0; i < snes->numberreasonviews; i++) {
4815: PetscBool identical;
4817: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))(PetscVoidFn *)f, vctx, reasonviewdestroy, (PetscErrorCode (*)(void))(PetscVoidFn *)snes->reasonview[i], snes->reasonviewcontext[i], snes->reasonviewdestroy[i], &identical));
4818: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4819: }
4820: PetscCheck(snes->numberreasonviews < MAXSNESREASONVIEWS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many SNES reasonview set");
4821: snes->reasonview[snes->numberreasonviews] = f;
4822: snes->reasonviewdestroy[snes->numberreasonviews] = reasonviewdestroy;
4823: snes->reasonviewcontext[snes->numberreasonviews++] = vctx;
4824: PetscFunctionReturn(PETSC_SUCCESS);
4825: }
4827: /*@
4828: SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a `SNESConvergedReason` is to be viewed at the end of `SNESSolve()`
4829: All the user-provided viewer routines set with `SNESConvergedReasonViewSet()` will be called, if they exist.
4831: Collective
4833: Input Parameter:
4834: . snes - the `SNES` object
4836: Level: advanced
4838: Note:
4839: This function has a different API and behavior than `PetscObjectViewFromOptions()`
4841: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESConvergedReasonViewSet()`, `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`,
4842: `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`
4843: @*/
4844: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4845: {
4846: static PetscBool incall = PETSC_FALSE;
4848: PetscFunctionBegin;
4849: if (incall) PetscFunctionReturn(PETSC_SUCCESS);
4850: incall = PETSC_TRUE;
4852: /* All user-provided viewers are called first, if they exist. */
4853: for (PetscInt i = 0; i < snes->numberreasonviews; i++) PetscCall((*snes->reasonview[i])(snes, snes->reasonviewcontext[i]));
4855: /* Call PETSc default routine if users ask for it */
4856: if (snes->convergedreasonviewer) {
4857: PetscCall(PetscViewerPushFormat(snes->convergedreasonviewer, snes->convergedreasonformat));
4858: PetscCall(SNESConvergedReasonView(snes, snes->convergedreasonviewer));
4859: PetscCall(PetscViewerPopFormat(snes->convergedreasonviewer));
4860: }
4861: incall = PETSC_FALSE;
4862: PetscFunctionReturn(PETSC_SUCCESS);
4863: }
4865: /*@
4866: SNESSolve - Solves a nonlinear system $F(x) = b $ associated with a `SNES` object
4868: Collective
4870: Input Parameters:
4871: + snes - the `SNES` context
4872: . b - the constant part of the equation $F(x) = b$, or `NULL` to use zero.
4873: - x - the solution vector.
4875: Level: beginner
4877: Note:
4878: The user should initialize the vector, `x`, with the initial guess
4879: for the nonlinear solve prior to calling `SNESSolve()` .
4881: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFunction()`, `SNESSetJacobian()`, `SNESSetGridSequence()`, `SNESGetSolution()`,
4882: `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRGetPreCheck()`, `SNESNewtonTRSetPostCheck()`, `SNESNewtonTRGetPostCheck()`,
4883: `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`
4884: @*/
4885: PetscErrorCode SNESSolve(SNES snes, Vec b, Vec x)
4886: {
4887: PetscBool flg;
4888: Vec xcreated = NULL;
4889: DM dm;
4891: PetscFunctionBegin;
4894: if (x) PetscCheckSameComm(snes, 1, x, 3);
4896: if (b) PetscCheckSameComm(snes, 1, b, 2);
4898: /* High level operations using the nonlinear solver */
4899: {
4900: PetscViewer viewer;
4901: PetscViewerFormat format;
4902: PetscInt num;
4903: PetscBool flg;
4904: static PetscBool incall = PETSC_FALSE;
4906: if (!incall) {
4907: /* Estimate the convergence rate of the discretization */
4908: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg));
4909: if (flg) {
4910: PetscConvEst conv;
4911: DM dm;
4912: PetscReal *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4913: PetscInt Nf;
4915: incall = PETSC_TRUE;
4916: PetscCall(SNESGetDM(snes, &dm));
4917: PetscCall(DMGetNumFields(dm, &Nf));
4918: PetscCall(PetscCalloc1(Nf, &alpha));
4919: PetscCall(PetscConvEstCreate(PetscObjectComm((PetscObject)snes), &conv));
4920: PetscCall(PetscConvEstSetSolver(conv, (PetscObject)snes));
4921: PetscCall(PetscConvEstSetFromOptions(conv));
4922: PetscCall(PetscConvEstSetUp(conv));
4923: PetscCall(PetscConvEstGetConvRate(conv, alpha));
4924: PetscCall(PetscViewerPushFormat(viewer, format));
4925: PetscCall(PetscConvEstRateView(conv, alpha, viewer));
4926: PetscCall(PetscViewerPopFormat(viewer));
4927: PetscCall(PetscViewerDestroy(&viewer));
4928: PetscCall(PetscConvEstDestroy(&conv));
4929: PetscCall(PetscFree(alpha));
4930: incall = PETSC_FALSE;
4931: }
4932: /* Adaptively refine the initial grid */
4933: num = 1;
4934: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_initial", &num, &flg));
4935: if (flg) {
4936: DMAdaptor adaptor;
4938: incall = PETSC_TRUE;
4939: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4940: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4941: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4942: PetscCall(DMAdaptorSetFromOptions(adaptor));
4943: PetscCall(DMAdaptorSetUp(adaptor));
4944: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x));
4945: PetscCall(DMAdaptorDestroy(&adaptor));
4946: incall = PETSC_FALSE;
4947: }
4948: /* Use grid sequencing to adapt */
4949: num = 0;
4950: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_sequence", &num, NULL));
4951: if (num) {
4952: DMAdaptor adaptor;
4953: const char *prefix;
4955: incall = PETSC_TRUE;
4956: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4957: PetscCall(SNESGetOptionsPrefix(snes, &prefix));
4958: PetscCall(DMAdaptorSetOptionsPrefix(adaptor, prefix));
4959: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4960: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4961: PetscCall(DMAdaptorSetFromOptions(adaptor));
4962: PetscCall(DMAdaptorSetUp(adaptor));
4963: PetscCall(PetscObjectViewFromOptions((PetscObject)adaptor, NULL, "-snes_adapt_view"));
4964: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x));
4965: PetscCall(DMAdaptorDestroy(&adaptor));
4966: incall = PETSC_FALSE;
4967: }
4968: }
4969: }
4970: if (!x) x = snes->vec_sol;
4971: if (!x) {
4972: PetscCall(SNESGetDM(snes, &dm));
4973: PetscCall(DMCreateGlobalVector(dm, &xcreated));
4974: x = xcreated;
4975: }
4976: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view_pre"));
4978: for (PetscInt grid = 0; grid < snes->gridsequence; grid++) PetscCall(PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4979: for (PetscInt grid = 0; grid < snes->gridsequence + 1; grid++) {
4980: /* set solution vector */
4981: if (!grid) PetscCall(PetscObjectReference((PetscObject)x));
4982: PetscCall(VecDestroy(&snes->vec_sol));
4983: snes->vec_sol = x;
4984: PetscCall(SNESGetDM(snes, &dm));
4986: /* set affine vector if provided */
4987: PetscCall(PetscObjectReference((PetscObject)b));
4988: PetscCall(VecDestroy(&snes->vec_rhs));
4989: snes->vec_rhs = b;
4991: 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");
4992: PetscCheck(snes->vec_func != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be function vector");
4993: PetscCheck(snes->vec_rhs != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be right-hand side vector");
4994: if (!snes->vec_sol_update /* && snes->vec_sol */) PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_sol_update));
4995: PetscCall(DMShellSetGlobalVector(dm, snes->vec_sol));
4996: PetscCall(SNESSetUp(snes));
4998: if (!grid) {
4999: if (snes->ops->computeinitialguess) PetscCallBack("SNES callback compute initial guess", (*snes->ops->computeinitialguess)(snes, snes->vec_sol, snes->initialguessP));
5000: }
5002: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
5003: PetscCall(SNESResetCounters(snes));
5004: snes->reason = SNES_CONVERGED_ITERATING;
5005: PetscCall(PetscLogEventBegin(SNES_Solve, snes, 0, 0, 0));
5006: PetscUseTypeMethod(snes, solve);
5007: PetscCall(PetscLogEventEnd(SNES_Solve, snes, 0, 0, 0));
5008: PetscCheck(snes->reason, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Internal error, solver %s returned without setting converged reason", ((PetscObject)snes)->type_name);
5009: snes->functiondomainerror = PETSC_FALSE; /* clear the flag if it has been set */
5010: snes->objectivedomainerror = PETSC_FALSE; /* clear the flag if it has been set */
5011: snes->jacobiandomainerror = PETSC_FALSE; /* clear the flag if it has been set */
5013: if (snes->lagjac_persist) snes->jac_iter += snes->iter;
5014: if (snes->lagpre_persist) snes->pre_iter += snes->iter;
5016: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_test_local_min", NULL, NULL, &flg));
5017: if (flg && !PetscPreLoadingOn) PetscCall(SNESTestLocalMin(snes));
5018: /* Call converged reason views. This may involve user-provided viewers as well */
5019: PetscCall(SNESConvergedReasonViewFromOptions(snes));
5021: if (snes->errorifnotconverged) {
5022: if (snes->reason < 0) PetscCall(SNESMonitorCancel(snes));
5023: PetscCheck(snes->reason >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_NOT_CONVERGED, "SNESSolve has not converged");
5024: }
5025: if (snes->reason < 0) break;
5026: if (grid < snes->gridsequence) {
5027: DM fine;
5028: Vec xnew;
5029: Mat interp;
5031: PetscCall(DMRefine(snes->dm, PetscObjectComm((PetscObject)snes), &fine));
5032: PetscCheck(fine, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "DMRefine() did not perform any refinement, cannot continue grid sequencing");
5033: PetscCall(DMGetCoordinatesLocalSetUp(fine));
5034: PetscCall(DMCreateInterpolation(snes->dm, fine, &interp, NULL));
5035: PetscCall(DMCreateGlobalVector(fine, &xnew));
5036: PetscCall(MatInterpolate(interp, x, xnew));
5037: PetscCall(DMInterpolate(snes->dm, interp, fine));
5038: PetscCall(MatDestroy(&interp));
5039: x = xnew;
5041: PetscCall(SNESReset(snes));
5042: PetscCall(SNESSetDM(snes, fine));
5043: PetscCall(SNESResetFromOptions(snes));
5044: PetscCall(DMDestroy(&fine));
5045: PetscCall(PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
5046: }
5047: }
5048: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view"));
5049: PetscCall(VecViewFromOptions(snes->vec_sol, (PetscObject)snes, "-snes_view_solution"));
5050: PetscCall(DMMonitor(snes->dm));
5051: PetscCall(SNESMonitorPauseFinal_Internal(snes));
5053: PetscCall(VecDestroy(&xcreated));
5054: PetscCall(PetscObjectSAWsBlock((PetscObject)snes));
5055: PetscFunctionReturn(PETSC_SUCCESS);
5056: }
5058: /* --------- Internal routines for SNES Package --------- */
5060: /*@
5061: SNESSetType - Sets the algorithm/method to be used to solve the nonlinear system with the given `SNES`
5063: Collective
5065: Input Parameters:
5066: + snes - the `SNES` context
5067: - type - a known method
5069: Options Database Key:
5070: . -snes_type type - Sets the method; see `SNESType`
5072: Level: intermediate
5074: Notes:
5075: See `SNESType` for available methods (for instance)
5076: + `SNESNEWTONLS` - Newton's method with line search
5077: (systems of nonlinear equations)
5078: - `SNESNEWTONTR` - Newton's method with trust region
5079: (systems of nonlinear equations)
5081: Normally, it is best to use the `SNESSetFromOptions()` command and then
5082: set the `SNES` solver type from the options database rather than by using
5083: this routine. Using the options database provides the user with
5084: maximum flexibility in evaluating the many nonlinear solvers.
5085: The `SNESSetType()` routine is provided for those situations where it
5086: is necessary to set the nonlinear solver independently of the command
5087: line or options database. This might be the case, for example, when
5088: the choice of solver changes during the execution of the program,
5089: and the user's application is taking responsibility for choosing the
5090: appropriate method.
5092: Developer Note:
5093: `SNESRegister()` adds a constructor for a new `SNESType` to `SNESList`, `SNESSetType()` locates
5094: the constructor in that list and calls it to create the specific object.
5096: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESType`, `SNESCreate()`, `SNESDestroy()`, `SNESGetType()`, `SNESSetFromOptions()`
5097: @*/
5098: PetscErrorCode SNESSetType(SNES snes, SNESType type)
5099: {
5100: PetscBool match;
5101: PetscErrorCode (*r)(SNES);
5103: PetscFunctionBegin;
5105: PetscAssertPointer(type, 2);
5107: PetscCall(PetscObjectTypeCompare((PetscObject)snes, type, &match));
5108: if (match) PetscFunctionReturn(PETSC_SUCCESS);
5110: PetscCall(PetscFunctionListFind(SNESList, type, &r));
5111: PetscCheck(r, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested SNES type %s", type);
5112: /* Destroy the previous private SNES context */
5113: PetscTryTypeMethod(snes, destroy);
5114: /* Reinitialize type-specific function pointers in SNESOps structure */
5115: snes->ops->reset = NULL;
5116: snes->ops->setup = NULL;
5117: snes->ops->solve = NULL;
5118: snes->ops->view = NULL;
5119: snes->ops->setfromoptions = NULL;
5120: snes->ops->destroy = NULL;
5122: /* It may happen the user has customized the line search before calling SNESSetType */
5123: if (((PetscObject)snes)->type_name) PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5125: /* Reinitialize default parameters */
5126: PetscCall(SNESParametersInitialize(snes));
5128: /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
5129: snes->setupcalled = PETSC_FALSE;
5130: PetscCall(PetscObjectChangeTypeName((PetscObject)snes, type));
5131: PetscCall((*r)(snes));
5132: PetscFunctionReturn(PETSC_SUCCESS);
5133: }
5135: /*@
5136: SNESGetType - Gets the `SNES` method type and name (as a string).
5138: Not Collective
5140: Input Parameter:
5141: . snes - nonlinear solver context
5143: Output Parameter:
5144: . type - `SNES` method (a character string)
5146: Level: intermediate
5148: Note:
5149: `type` should not be retained for later use as it will be an invalid pointer if the `SNESType` of `snes` is changed.
5151: .seealso: [](ch_snes), `SNESSetType()`, `SNESType`, `SNESSetFromOptions()`, `SNES`, `PetscObjectTypeCompare()`, `PetscObjectTypeCompareAny()`
5152: @*/
5153: PetscErrorCode SNESGetType(SNES snes, SNESType *type)
5154: {
5155: PetscFunctionBegin;
5157: PetscAssertPointer(type, 2);
5158: *type = ((PetscObject)snes)->type_name;
5159: PetscFunctionReturn(PETSC_SUCCESS);
5160: }
5162: /*@
5163: SNESSetSolution - Sets the solution vector for use by the `SNES` routines.
5165: Logically Collective
5167: Input Parameters:
5168: + snes - the `SNES` context obtained from `SNESCreate()`
5169: - u - the solution vector
5171: Level: beginner
5173: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetSolution()`, `Vec`
5174: @*/
5175: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
5176: {
5177: DM dm;
5179: PetscFunctionBegin;
5182: PetscCall(PetscObjectReference((PetscObject)u));
5183: PetscCall(VecDestroy(&snes->vec_sol));
5185: snes->vec_sol = u;
5187: PetscCall(SNESGetDM(snes, &dm));
5188: PetscCall(DMShellSetGlobalVector(dm, u));
5189: PetscFunctionReturn(PETSC_SUCCESS);
5190: }
5192: /*@
5193: SNESGetSolution - Returns the vector where the approximate solution is
5194: stored. This is the fine grid solution when using `SNESSetGridSequence()`.
5196: Not Collective, but `x` is parallel if `snes` is parallel
5198: Input Parameter:
5199: . snes - the `SNES` context
5201: Output Parameter:
5202: . x - the solution
5204: Level: intermediate
5206: .seealso: [](ch_snes), `SNESSetSolution()`, `SNESSolve()`, `SNES`, `SNESGetSolutionUpdate()`, `SNESGetFunction()`
5207: @*/
5208: PetscErrorCode SNESGetSolution(SNES snes, Vec *x)
5209: {
5210: PetscFunctionBegin;
5212: PetscAssertPointer(x, 2);
5213: *x = snes->vec_sol;
5214: PetscFunctionReturn(PETSC_SUCCESS);
5215: }
5217: /*@
5218: SNESGetSolutionUpdate - Returns the vector where the solution update is
5219: stored.
5221: Not Collective, but `x` is parallel if `snes` is parallel
5223: Input Parameter:
5224: . snes - the `SNES` context
5226: Output Parameter:
5227: . x - the solution update
5229: Level: advanced
5231: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`
5232: @*/
5233: PetscErrorCode SNESGetSolutionUpdate(SNES snes, Vec *x)
5234: {
5235: PetscFunctionBegin;
5237: PetscAssertPointer(x, 2);
5238: *x = snes->vec_sol_update;
5239: PetscFunctionReturn(PETSC_SUCCESS);
5240: }
5242: /*@
5243: SNESGetFunction - Returns the function that defines the nonlinear system set with `SNESSetFunction()`
5245: Not Collective, but `r` is parallel if `snes` is parallel. Collective if `r` is requested, but has not been created yet.
5247: Input Parameter:
5248: . snes - the `SNES` context
5250: Output Parameters:
5251: + r - the vector that is used to store residuals (or `NULL` if you don't want it)
5252: . f - the function (or `NULL` if you don't want it); for calling sequence see `SNESFunctionFn`
5253: - ctx - the function context (or `NULL` if you don't want it)
5255: Level: advanced
5257: Note:
5258: The vector `r` DOES NOT, in general, contain the current value of the `SNES` nonlinear function
5260: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetSolution()`, `SNESFunctionFn`
5261: @*/
5262: PetscErrorCode SNESGetFunction(SNES snes, Vec *r, SNESFunctionFn **f, PetscCtxRt ctx)
5263: {
5264: DM dm;
5266: PetscFunctionBegin;
5268: if (r) {
5269: if (!snes->vec_func) {
5270: if (snes->vec_rhs) {
5271: PetscCall(VecDuplicate(snes->vec_rhs, &snes->vec_func));
5272: } else if (snes->vec_sol) {
5273: PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_func));
5274: } else if (snes->dm) {
5275: PetscCall(DMCreateGlobalVector(snes->dm, &snes->vec_func));
5276: }
5277: }
5278: *r = snes->vec_func;
5279: }
5280: PetscCall(SNESGetDM(snes, &dm));
5281: PetscCall(DMSNESGetFunction(dm, f, ctx));
5282: PetscFunctionReturn(PETSC_SUCCESS);
5283: }
5285: /*@
5286: SNESGetNGS - Returns the function and context set with `SNESSetNGS()`
5288: Input Parameter:
5289: . snes - the `SNES` context
5291: Output Parameters:
5292: + f - the function (or `NULL`) see `SNESNGSFn` for calling sequence
5293: - ctx - the function context (or `NULL`)
5295: Level: advanced
5297: .seealso: [](ch_snes), `SNESSetNGS()`, `SNESGetFunction()`, `SNESNGSFn`
5298: @*/
5299: PetscErrorCode SNESGetNGS(SNES snes, SNESNGSFn **f, PetscCtxRt ctx)
5300: {
5301: DM dm;
5303: PetscFunctionBegin;
5305: PetscCall(SNESGetDM(snes, &dm));
5306: PetscCall(DMSNESGetNGS(dm, f, ctx));
5307: PetscFunctionReturn(PETSC_SUCCESS);
5308: }
5310: /*@
5311: SNESSetOptionsPrefix - Sets the prefix used for searching for all
5312: `SNES` options in the database.
5314: Logically Collective
5316: Input Parameters:
5317: + snes - the `SNES` context
5318: - prefix - the prefix to prepend to all option names
5320: Level: advanced
5322: Note:
5323: A hyphen (-) must NOT be given at the beginning of the prefix name.
5324: The first character of all runtime options is AUTOMATICALLY the hyphen.
5326: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESAppendOptionsPrefix()`
5327: @*/
5328: PetscErrorCode SNESSetOptionsPrefix(SNES snes, const char prefix[])
5329: {
5330: PetscFunctionBegin;
5332: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes, prefix));
5333: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5334: if (snes->linesearch) {
5335: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5336: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch, prefix));
5337: }
5338: PetscCall(KSPSetOptionsPrefix(snes->ksp, prefix));
5339: PetscFunctionReturn(PETSC_SUCCESS);
5340: }
5342: /*@
5343: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
5344: `SNES` options in the database.
5346: Logically Collective
5348: Input Parameters:
5349: + snes - the `SNES` context
5350: - prefix - the prefix to prepend to all option names
5352: Level: advanced
5354: Note:
5355: A hyphen (-) must NOT be given at the beginning of the prefix name.
5356: The first character of all runtime options is AUTOMATICALLY the hyphen.
5358: .seealso: [](ch_snes), `SNESGetOptionsPrefix()`, `SNESSetOptionsPrefix()`
5359: @*/
5360: PetscErrorCode SNESAppendOptionsPrefix(SNES snes, const char prefix[])
5361: {
5362: PetscFunctionBegin;
5364: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes, prefix));
5365: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5366: if (snes->linesearch) {
5367: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5368: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch, prefix));
5369: }
5370: PetscCall(KSPAppendOptionsPrefix(snes->ksp, prefix));
5371: PetscFunctionReturn(PETSC_SUCCESS);
5372: }
5374: /*@
5375: SNESGetOptionsPrefix - Gets the prefix used for searching for all
5376: `SNES` options in the database.
5378: Not Collective
5380: Input Parameter:
5381: . snes - the `SNES` context
5383: Output Parameter:
5384: . prefix - pointer to the prefix string used
5386: Level: advanced
5388: .seealso: [](ch_snes), `SNES`, `SNESSetOptionsPrefix()`, `SNESAppendOptionsPrefix()`
5389: @*/
5390: PetscErrorCode SNESGetOptionsPrefix(SNES snes, const char *prefix[])
5391: {
5392: PetscFunctionBegin;
5394: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, prefix));
5395: PetscFunctionReturn(PETSC_SUCCESS);
5396: }
5398: /*@
5399: SNESRegister - Adds a method to the nonlinear solver package.
5401: Not Collective
5403: Input Parameters:
5404: + sname - name of a new user-defined solver
5405: - function - routine to create method context
5407: Level: advanced
5409: Note:
5410: `SNESRegister()` may be called multiple times to add several user-defined solvers.
5412: Example Usage:
5413: .vb
5414: SNESRegister("my_solver", MySolverCreate);
5415: .ve
5417: Then, your solver can be chosen with the procedural interface via
5418: .vb
5419: SNESSetType(snes, "my_solver")
5420: .ve
5421: or at runtime via the option
5422: .vb
5423: -snes_type my_solver
5424: .ve
5426: .seealso: [](ch_snes), `SNESRegisterAll()`, `SNESRegisterDestroy()`
5427: @*/
5428: PetscErrorCode SNESRegister(const char sname[], PetscErrorCode (*function)(SNES))
5429: {
5430: PetscFunctionBegin;
5431: PetscCall(SNESInitializePackage());
5432: PetscCall(PetscFunctionListAdd(&SNESList, sname, function));
5433: PetscFunctionReturn(PETSC_SUCCESS);
5434: }
5436: /*@
5437: SNESTestLocalMin - Diagnostic that probes each entry of the current `SNES` solution to check whether the residual norm has a local minimum along the coordinate directions
5439: Collective
5441: Input Parameter:
5442: . snes - the `SNES` context
5444: Level: developer
5446: Note:
5447: Currently intended for serial runs. For each degree of freedom it perturbs the solution by increasing amounts and prints the resulting `SNESComputeFunction()` residual norms so the user can inspect local behavior.
5449: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESComputeFunction()`
5450: @*/
5451: PetscErrorCode SNESTestLocalMin(SNES snes)
5452: {
5453: PetscInt N, i, j;
5454: Vec u, uh, fh;
5455: PetscScalar value;
5456: PetscReal norm;
5458: PetscFunctionBegin;
5459: PetscCall(SNESGetSolution(snes, &u));
5460: PetscCall(VecDuplicate(u, &uh));
5461: PetscCall(VecDuplicate(u, &fh));
5463: /* currently only works for sequential */
5464: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "Testing FormFunction() for local min\n"));
5465: PetscCall(VecGetSize(u, &N));
5466: for (i = 0; i < N; i++) {
5467: PetscCall(VecCopy(u, uh));
5468: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "i = %" PetscInt_FMT "\n", i));
5469: for (j = -10; j < 11; j++) {
5470: value = PetscSign(j) * PetscExpReal(PetscAbs(j) - 10.0);
5471: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5472: PetscCall(SNESComputeFunction(snes, uh, fh));
5473: PetscCall(VecNorm(fh, NORM_2, &norm)); /* does not handle use of SNESSetFunctionDomainError() correctly */
5474: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), " j norm %" PetscInt_FMT " %18.16e\n", j, (double)norm));
5475: value = -value;
5476: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5477: }
5478: }
5479: PetscCall(VecDestroy(&uh));
5480: PetscCall(VecDestroy(&fh));
5481: PetscFunctionReturn(PETSC_SUCCESS);
5482: }
5484: /*@
5485: SNESGetLineSearch - Returns the line search associated with the `SNES`.
5487: Not Collective
5489: Input Parameter:
5490: . snes - iterative context obtained from `SNESCreate()`
5492: Output Parameter:
5493: . linesearch - linesearch context
5495: Level: beginner
5497: Notes:
5498: It creates a default line search instance which can be configured as needed in case it has not been already set with `SNESSetLineSearch()`.
5500: You can also use the options database keys `-snes_linesearch_*` to configure the line search. See `SNESLineSearchSetFromOptions()` for the possible options.
5502: .seealso: [](ch_snes), `SNESLineSearch`, `SNESSetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`
5503: @*/
5504: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5505: {
5506: const char *optionsprefix;
5508: PetscFunctionBegin;
5510: PetscAssertPointer(linesearch, 2);
5511: if (!snes->linesearch) {
5512: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5513: PetscCall(SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch));
5514: PetscCall(SNESLineSearchSetSNES(snes->linesearch, snes));
5515: PetscCall(SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix));
5516: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->linesearch, (PetscObject)snes, 1));
5517: }
5518: *linesearch = snes->linesearch;
5519: PetscFunctionReturn(PETSC_SUCCESS);
5520: }
5522: /*@
5523: SNESKSPSetUseEW - Sets `SNES` to the use Eisenstat-Walker method for
5524: computing relative tolerance for linear solvers within an inexact
5525: Newton method.
5527: Logically Collective
5529: Input Parameters:
5530: + snes - `SNES` context
5531: - flag - `PETSC_TRUE` or `PETSC_FALSE`
5533: Options Database Keys:
5534: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5535: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
5536: . -snes_ksp_ew_rtol0 rtol0 - Sets rtol0
5537: . -snes_ksp_ew_rtolmax rtolmax - Sets rtolmax
5538: . -snes_ksp_ew_gamma gamma - Sets gamma
5539: . -snes_ksp_ew_alpha alpha - Sets alpha
5540: . -snes_ksp_ew_alpha2 alpha2 - Sets alpha2
5541: - -snes_ksp_ew_threshold threshold - Sets threshold
5543: Level: advanced
5545: Note:
5546: The default is to use a constant relative tolerance for
5547: the inner linear solvers. Alternatively, one can use the
5548: Eisenstat-Walker method {cite}`ew96`, where the relative convergence tolerance
5549: is reset at each Newton iteration according progress of the nonlinear
5550: solver.
5552: .seealso: [](ch_snes), `KSP`, `SNES`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5553: @*/
5554: PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)
5555: {
5556: PetscFunctionBegin;
5559: snes->ksp_ewconv = flag;
5560: PetscFunctionReturn(PETSC_SUCCESS);
5561: }
5563: /*@
5564: SNESKSPGetUseEW - Gets if `SNES` is using Eisenstat-Walker method
5565: for computing relative tolerance for linear solvers within an
5566: inexact Newton method.
5568: Not Collective
5570: Input Parameter:
5571: . snes - `SNES` context
5573: Output Parameter:
5574: . flag - `PETSC_TRUE` or `PETSC_FALSE`
5576: Level: advanced
5578: .seealso: [](ch_snes), `SNESKSPSetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5579: @*/
5580: PetscErrorCode SNESKSPGetUseEW(SNES snes, PetscBool *flag)
5581: {
5582: PetscFunctionBegin;
5584: PetscAssertPointer(flag, 2);
5585: *flag = snes->ksp_ewconv;
5586: PetscFunctionReturn(PETSC_SUCCESS);
5587: }
5589: /*@
5590: SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5591: convergence criteria for the linear solvers within an inexact
5592: Newton method.
5594: Logically Collective
5596: Input Parameters:
5597: + snes - `SNES` context
5598: . version - version 1, 2 (default is 2), 3 or 4
5599: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5600: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5601: . gamma - multiplicative factor for version 2 rtol computation
5602: (0 <= gamma2 <= 1)
5603: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5604: . alpha2 - power for safeguard
5605: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5607: Level: advanced
5609: Notes:
5610: Version 3 was contributed by Luis Chacon, June 2006.
5612: Use `PETSC_CURRENT` to retain the default for any of the parameters.
5614: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`
5615: @*/
5616: PetscErrorCode SNESKSPSetParametersEW(SNES snes, PetscInt version, PetscReal rtol_0, PetscReal rtol_max, PetscReal gamma, PetscReal alpha, PetscReal alpha2, PetscReal threshold)
5617: {
5618: SNESKSPEW *kctx;
5620: PetscFunctionBegin;
5622: kctx = (SNESKSPEW *)snes->kspconvctx;
5623: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5632: if (version != PETSC_CURRENT) kctx->version = version;
5633: if (rtol_0 != (PetscReal)PETSC_CURRENT) kctx->rtol_0 = rtol_0;
5634: if (rtol_max != (PetscReal)PETSC_CURRENT) kctx->rtol_max = rtol_max;
5635: if (gamma != (PetscReal)PETSC_CURRENT) kctx->gamma = gamma;
5636: if (alpha != (PetscReal)PETSC_CURRENT) kctx->alpha = alpha;
5637: if (alpha2 != (PetscReal)PETSC_CURRENT) kctx->alpha2 = alpha2;
5638: if (threshold != (PetscReal)PETSC_CURRENT) kctx->threshold = threshold;
5640: 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);
5641: 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);
5642: 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);
5643: 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);
5644: 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);
5645: 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);
5646: PetscFunctionReturn(PETSC_SUCCESS);
5647: }
5649: /*@
5650: SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5651: convergence criteria for the linear solvers within an inexact
5652: Newton method.
5654: Not Collective
5656: Input Parameter:
5657: . snes - `SNES` context
5659: Output Parameters:
5660: + version - version 1, 2 (default is 2), 3 or 4
5661: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5662: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5663: . gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5664: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5665: . alpha2 - power for safeguard
5666: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5668: Level: advanced
5670: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPSetParametersEW()`
5671: @*/
5672: PetscErrorCode SNESKSPGetParametersEW(SNES snes, PetscInt *version, PetscReal *rtol_0, PetscReal *rtol_max, PetscReal *gamma, PetscReal *alpha, PetscReal *alpha2, PetscReal *threshold)
5673: {
5674: SNESKSPEW *kctx;
5676: PetscFunctionBegin;
5678: kctx = (SNESKSPEW *)snes->kspconvctx;
5679: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5680: if (version) *version = kctx->version;
5681: if (rtol_0) *rtol_0 = kctx->rtol_0;
5682: if (rtol_max) *rtol_max = kctx->rtol_max;
5683: if (gamma) *gamma = kctx->gamma;
5684: if (alpha) *alpha = kctx->alpha;
5685: if (alpha2) *alpha2 = kctx->alpha2;
5686: if (threshold) *threshold = kctx->threshold;
5687: PetscFunctionReturn(PETSC_SUCCESS);
5688: }
5690: PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, PetscCtx ctx)
5691: {
5692: SNES snes = (SNES)ctx;
5693: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5694: PetscReal rtol = PETSC_CURRENT, stol;
5696: PetscFunctionBegin;
5697: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5698: if (!snes->iter) {
5699: rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5700: PetscCall(VecNorm(snes->vec_func, NORM_2, &kctx->norm_first));
5701: } else {
5702: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1-4 are supported: %" PetscInt_FMT, kctx->version);
5703: if (kctx->version == 1) {
5704: rtol = PetscAbsReal(snes->norm - kctx->lresid_last) / kctx->norm_last;
5705: stol = PetscPowReal(kctx->rtol_last, kctx->alpha2);
5706: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5707: } else if (kctx->version == 2) {
5708: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5709: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5710: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5711: } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5712: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5713: /* safeguard: avoid sharp decrease of rtol */
5714: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5715: stol = PetscMax(rtol, stol);
5716: rtol = PetscMin(kctx->rtol_0, stol);
5717: /* safeguard: avoid oversolving */
5718: stol = kctx->gamma * (kctx->norm_first * snes->rtol) / snes->norm;
5719: stol = PetscMax(rtol, stol);
5720: rtol = PetscMin(kctx->rtol_0, stol);
5721: } else /* if (kctx->version == 4) */ {
5722: /* H.-B. An et al. Journal of Computational and Applied Mathematics 200 (2007) 47-60 */
5723: PetscReal ared = PetscAbsReal(kctx->norm_last - snes->norm);
5724: PetscReal pred = PetscAbsReal(kctx->norm_last - kctx->lresid_last);
5725: PetscReal rk = ared / pred;
5726: if (rk < kctx->v4_p1) rtol = 1. - 2. * kctx->v4_p1;
5727: else if (rk < kctx->v4_p2) rtol = kctx->rtol_last;
5728: else if (rk < kctx->v4_p3) rtol = kctx->v4_m1 * kctx->rtol_last;
5729: else rtol = kctx->v4_m2 * kctx->rtol_last;
5731: 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;
5732: kctx->rtol_last_2 = kctx->rtol_last;
5733: kctx->rk_last_2 = kctx->rk_last;
5734: kctx->rk_last = rk;
5735: }
5736: }
5737: /* safeguard: avoid rtol greater than rtol_max */
5738: rtol = PetscMin(rtol, kctx->rtol_max);
5739: PetscCall(KSPSetTolerances(ksp, rtol, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT));
5740: PetscCall(PetscInfo(snes, "iter %" PetscInt_FMT ", Eisenstat-Walker (version %" PetscInt_FMT ") KSP rtol=%g\n", snes->iter, kctx->version, (double)rtol));
5741: PetscFunctionReturn(PETSC_SUCCESS);
5742: }
5744: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, PetscCtx ctx)
5745: {
5746: SNES snes = (SNES)ctx;
5747: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5748: PCSide pcside;
5749: Vec lres;
5751: PetscFunctionBegin;
5752: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5753: PetscCall(KSPGetTolerances(ksp, &kctx->rtol_last, NULL, NULL, NULL));
5754: kctx->norm_last = snes->norm;
5755: if (kctx->version == 1 || kctx->version == 4) {
5756: PC pc;
5757: PetscBool getRes;
5759: PetscCall(KSPGetPC(ksp, &pc));
5760: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCNONE, &getRes));
5761: if (!getRes) {
5762: KSPNormType normtype;
5764: PetscCall(KSPGetNormType(ksp, &normtype));
5765: getRes = (PetscBool)(normtype == KSP_NORM_UNPRECONDITIONED);
5766: }
5767: PetscCall(KSPGetPCSide(ksp, &pcside));
5768: if (pcside == PC_RIGHT || getRes) { /* KSP residual is true linear residual */
5769: PetscCall(KSPGetResidualNorm(ksp, &kctx->lresid_last));
5770: } else {
5771: /* KSP residual is preconditioned residual */
5772: /* compute true linear residual norm */
5773: Mat J;
5774: PetscCall(KSPGetOperators(ksp, &J, NULL));
5775: PetscCall(VecDuplicate(b, &lres));
5776: PetscCall(MatMult(J, x, lres));
5777: PetscCall(VecAYPX(lres, -1.0, b));
5778: PetscCall(VecNorm(lres, NORM_2, &kctx->lresid_last));
5779: PetscCall(VecDestroy(&lres));
5780: }
5781: }
5782: PetscFunctionReturn(PETSC_SUCCESS);
5783: }
5785: #include <petsc/private/kspimpl.h>
5786: /*@
5787: SNESGetKSP - Returns the `KSP` context for a `SNES` solver.
5789: Not Collective, but if `snes` is parallel, then `ksp` is parallel
5791: Input Parameter:
5792: . snes - the `SNES` context
5794: Output Parameter:
5795: . ksp - the `KSP` context
5797: Level: beginner
5799: Notes:
5800: The user can then directly manipulate the `KSP` context to set various
5801: options, etc. Likewise, the user can then extract and manipulate the
5802: `PC` contexts as well.
5804: 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.
5806: .seealso: [](ch_snes), `SNES`, `KSP`, `PC`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
5807: @*/
5808: PetscErrorCode SNESGetKSP(SNES snes, KSP *ksp)
5809: {
5810: PetscFunctionBegin;
5812: PetscAssertPointer(ksp, 2);
5814: if (!snes->ksp) {
5815: PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes), &snes->ksp));
5816: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->ksp, (PetscObject)snes, 1));
5818: snes->ksp->presolve_ew = KSPPreSolve_SNESEW;
5819: snes->ksp->prectx_ew = snes;
5820: snes->ksp->postsolve_ew = KSPPostSolve_SNESEW;
5821: snes->ksp->postctx_ew = snes;
5823: PetscCall(KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes));
5824: PetscCall(PetscObjectSetOptions((PetscObject)snes->ksp, ((PetscObject)snes)->options));
5825: }
5826: *ksp = snes->ksp;
5827: PetscFunctionReturn(PETSC_SUCCESS);
5828: }
5830: #include <petsc/private/dmimpl.h>
5831: /*@
5832: SNESSetDM - Sets the `DM` that may be used by some `SNES` nonlinear solvers or their underlying preconditioners
5834: Logically Collective
5836: Input Parameters:
5837: + snes - the nonlinear solver context
5838: - dm - the `DM`, cannot be `NULL`
5840: Level: intermediate
5842: Note:
5843: A `DM` can only be used for solving one problem at a time because information about the problem is stored on the `DM`,
5844: even when not using interfaces like `DMSNESSetFunction()`. Use `DMClone()` to get a distinct `DM` when solving different
5845: problems using the same function space.
5847: .seealso: [](ch_snes), `DM`, `SNES`, `SNESGetDM()`, `KSPSetDM()`, `KSPGetDM()`
5848: @*/
5849: PetscErrorCode SNESSetDM(SNES snes, DM dm)
5850: {
5851: KSP ksp;
5852: DMSNES sdm;
5853: DM odm;
5855: PetscFunctionBegin;
5858: PetscCall(PetscObjectReference((PetscObject)dm));
5859: odm = snes->dm;
5860: if (snes->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
5861: if (snes->dm->dmsnes && !dm->dmsnes) {
5862: PetscCall(DMCopyDMSNES(snes->dm, dm));
5863: PetscCall(DMGetDMSNES(snes->dm, &sdm));
5864: if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5865: }
5866: PetscCall(DMCoarsenHookRemove(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
5867: PetscCall(DMDestroy(&snes->dm));
5868: }
5869: snes->dm = dm;
5870: snes->dmAuto = PETSC_FALSE;
5872: PetscCall(SNESGetKSP(snes, &ksp));
5873: PetscCall(KSPSetDM(ksp, dm));
5874: PetscCall(KSPSetDMActive(ksp, KSP_DMACTIVE_ALL, PETSC_FALSE));
5875: /* Propagate DM to NPC if npc does not have one yet or
5876: if it has the same DM SNES had before (like for gridsequencing) */
5877: if (snes->npc && (!snes->npc->dm || snes->npc->dm == odm)) PetscCall(SNESSetDM(snes->npc, snes->dm));
5878: PetscFunctionReturn(PETSC_SUCCESS);
5879: }
5881: /*@
5882: SNESGetDM - Gets the `DM` that may be used by some `SNES` nonlinear solvers/preconditioners
5884: Not Collective but `dm` obtained is parallel on `snes`
5886: Input Parameter:
5887: . snes - the `SNES` context
5889: Output Parameter:
5890: . dm - the `DM`
5892: Level: intermediate
5894: .seealso: [](ch_snes), `DM`, `SNES`, `SNESSetDM()`, `KSPSetDM()`, `KSPGetDM()`
5895: @*/
5896: PetscErrorCode SNESGetDM(SNES snes, DM *dm)
5897: {
5898: PetscFunctionBegin;
5900: if (!snes->dm) {
5901: PetscCall(DMShellCreate(PetscObjectComm((PetscObject)snes), &snes->dm));
5902: snes->dmAuto = PETSC_TRUE;
5903: }
5904: *dm = snes->dm;
5905: PetscFunctionReturn(PETSC_SUCCESS);
5906: }
5908: /*@
5909: SNESSetNPC - Sets the nonlinear preconditioner to be used.
5911: Collective
5913: Input Parameters:
5914: + snes - iterative context obtained from `SNESCreate()`
5915: - npc - the `SNES` nonlinear preconditioner object
5917: Level: developer
5919: Notes:
5920: This is rarely used, rather use `SNESGetNPC()` to retrieve the preconditioner and configure it using the API.
5922: Only some `SNESType` can use a nonlinear preconditioner
5924: .seealso: [](ch_snes), `SNES`, `SNESNGS`, `SNESFAS`, `SNESGetNPC()`, `SNESHasNPC()`
5925: @*/
5926: PetscErrorCode SNESSetNPC(SNES snes, SNES npc)
5927: {
5928: PetscFunctionBegin;
5931: PetscCheckSameComm(snes, 1, npc, 2);
5932: PetscCall(PetscObjectReference((PetscObject)npc));
5933: PetscCall(SNESDestroy(&snes->npc));
5934: snes->npc = npc;
5935: PetscFunctionReturn(PETSC_SUCCESS);
5936: }
5938: /*@
5939: SNESGetNPC - Gets a nonlinear preconditioning solver SNES` to be used to precondition the original nonlinear solver.
5941: Collective the first time it is called if the `SNES` has no NPC set.
5943: Input Parameter:
5944: . snes - iterative context obtained from `SNESCreate()`
5946: Output Parameter:
5947: . npc - the `SNES` preconditioner context
5949: Options Database Key:
5950: . -npc_snes_type type - set the type of the `SNES` to use as the nonlinear preconditioner
5952: Level: advanced
5954: Notes:
5955: If a `SNES` was previously set with `SNESSetNPC()` then that object is returned, otherwise a new `SNES` object is created that will
5956: be used as the nonlinear preconditioner for the current `SNES` if no nonlinear preconditioner is present.
5958: The (preconditioner) `SNES` returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5959: `SNES`. These may be overwritten if needed by calling `SNESSetDM()` on the nonlinear preconditioner followed by `SNESSetFunction()`
5960: and `SNESSetJacobian()`.
5962: The default preconditioner uses the options database prefixes `-npc_snes`, `-npc_ksp`, etc., to control the configuration.
5964: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESHasNPC()`, `SNES`, `SNESCreate()`
5965: @*/
5966: PetscErrorCode SNESGetNPC(SNES snes, SNES *npc)
5967: {
5968: const char *optionsprefix;
5970: PetscFunctionBegin;
5972: PetscAssertPointer(npc, 2);
5973: if (!snes->npc) {
5974: PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &snes->npc));
5975: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->npc, (PetscObject)snes, 1));
5976: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5977: PetscCall(SNESSetOptionsPrefix(snes->npc, optionsprefix));
5978: PetscCall(SNESAppendOptionsPrefix(snes->npc, "npc_"));
5979: PetscCall(SNESSetCountersReset(snes->npc, PETSC_FALSE));
5980: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_DEFAULT));
5982: /* default to 1 iteration */
5983: PetscCall(SNESSetTolerances(snes->npc, 0.0, 0.0, 0.0, 1, snes->npc->max_funcs));
5984: }
5985: *npc = snes->npc;
5986: PetscFunctionReturn(PETSC_SUCCESS);
5987: }
5989: /*@
5990: SNESHasNPC - Returns whether a nonlinear preconditioner is associated with the given `SNES`
5992: Not Collective
5994: Input Parameter:
5995: . snes - iterative context obtained from `SNESCreate()`
5997: Output Parameter:
5998: . has_npc - whether the `SNES` has a nonlinear preconditioner or not
6000: Level: developer
6002: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESGetNPC()`
6003: @*/
6004: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
6005: {
6006: PetscFunctionBegin;
6008: PetscAssertPointer(has_npc, 2);
6009: *has_npc = snes->npc ? PETSC_TRUE : PETSC_FALSE;
6010: PetscFunctionReturn(PETSC_SUCCESS);
6011: }
6013: /*@
6014: SNESSetNPCSide - Sets the nonlinear preconditioning side used by the nonlinear preconditioner inside `SNES`.
6016: Logically Collective
6018: Input Parameter:
6019: . snes - iterative context obtained from `SNESCreate()`
6021: Output Parameter:
6022: . side - the preconditioning side, where side is one of
6023: .vb
6024: PC_LEFT - left preconditioning
6025: PC_RIGHT - right preconditioning (default for most nonlinear solvers)
6026: .ve
6028: Options Database Key:
6029: . -snes_npc_side (right|left) - nonlinear preconditioner side
6031: Level: intermediate
6033: Note:
6034: `SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.
6036: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESNRICHARDSON`, `SNESNCG`, `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
6037: @*/
6038: PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
6039: {
6040: PetscFunctionBegin;
6043: if (side == PC_SIDE_DEFAULT) side = PC_RIGHT;
6044: PetscCheck((side == PC_LEFT) || (side == PC_RIGHT), PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Only PC_LEFT and PC_RIGHT are supported");
6045: snes->npcside = side;
6046: PetscFunctionReturn(PETSC_SUCCESS);
6047: }
6049: /*@
6050: SNESGetNPCSide - Gets the preconditioning side used by the nonlinear preconditioner inside `SNES`.
6052: Not Collective
6054: Input Parameter:
6055: . snes - iterative context obtained from `SNESCreate()`
6057: Output Parameter:
6058: . side - the preconditioning side, where side is one of
6059: .vb
6060: `PC_LEFT` - left preconditioning
6061: `PC_RIGHT` - right preconditioning (default for most nonlinear solvers)
6062: .ve
6064: Level: intermediate
6066: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESSetNPCSide()`, `KSPGetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
6067: @*/
6068: PetscErrorCode SNESGetNPCSide(SNES snes, PCSide *side)
6069: {
6070: PetscFunctionBegin;
6072: PetscAssertPointer(side, 2);
6073: *side = snes->npcside;
6074: PetscFunctionReturn(PETSC_SUCCESS);
6075: }
6077: /*@
6078: SNESSetLineSearch - Sets the `SNESLineSearch` to be used for a given `SNES`
6080: Collective
6082: Input Parameters:
6083: + snes - iterative context obtained from `SNESCreate()`
6084: - linesearch - the linesearch object
6086: Level: developer
6088: Note:
6089: This is almost never used, rather one uses `SNESGetLineSearch()` to retrieve the line search and set options on it
6090: to configure it using the API).
6092: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`
6093: @*/
6094: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
6095: {
6096: PetscFunctionBegin;
6099: PetscCheckSameComm(snes, 1, linesearch, 2);
6100: PetscCall(PetscObjectReference((PetscObject)linesearch));
6101: PetscCall(SNESLineSearchDestroy(&snes->linesearch));
6103: snes->linesearch = linesearch;
6104: PetscFunctionReturn(PETSC_SUCCESS);
6105: }