Actual source code: snes.c
1: #include <petsc/private/snesimpl.h>
2: #include <petscdmshell.h>
3: #include <petscdraw.h>
4: #include <petscds.h>
5: #include <petscdmadaptor.h>
6: #include <petscconvest.h>
8: PetscBool SNESRegisterAllCalled = PETSC_FALSE;
9: PetscFunctionList SNESList = NULL;
11: /* Logging support */
12: PetscClassId SNES_CLASSID, DMSNES_CLASSID;
13: PetscLogEvent SNES_Solve, SNES_SetUp, SNES_FunctionEval, SNES_JacobianEval, SNES_NGSEval, SNES_NGSFuncEval, SNES_NewtonALEval, SNES_NPCSolve, SNES_ObjectiveEval;
15: /*@
16: SNESSetErrorIfNotConverged - Causes `SNESSolve()` to generate an error immediately if the solver has not converged.
18: Logically Collective
20: Input Parameters:
21: + snes - iterative context obtained from `SNESCreate()`
22: - flg - `PETSC_TRUE` indicates you want the error generated
24: Options Database Key:
25: . -snes_error_if_not_converged <true,false> - cause an immediate error condition and stop the program if the solver does not converge
27: Level: intermediate
29: Note:
30: Normally PETSc continues if a solver fails to converge, you can call `SNESGetConvergedReason()` after a `SNESSolve()`
31: to determine if it has converged. Otherwise the solution may be inaccurate or wrong
33: .seealso: [](ch_snes), `SNES`, `SNESGetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
34: @*/
35: PetscErrorCode SNESSetErrorIfNotConverged(SNES snes, PetscBool flg)
36: {
37: PetscFunctionBegin;
40: snes->errorifnotconverged = flg;
41: PetscFunctionReturn(PETSC_SUCCESS);
42: }
44: /*@
45: SNESGetErrorIfNotConverged - Indicates if `SNESSolve()` will generate an error if the solver does not converge?
47: Not Collective
49: Input Parameter:
50: . snes - iterative context obtained from `SNESCreate()`
52: Output Parameter:
53: . flag - `PETSC_TRUE` if it will generate an error, else `PETSC_FALSE`
55: Level: intermediate
57: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
58: @*/
59: PetscErrorCode SNESGetErrorIfNotConverged(SNES snes, PetscBool *flag)
60: {
61: PetscFunctionBegin;
63: PetscAssertPointer(flag, 2);
64: *flag = snes->errorifnotconverged;
65: PetscFunctionReturn(PETSC_SUCCESS);
66: }
68: /*@
69: SNESSetAlwaysComputesFinalResidual - tells the `SNES` to always compute the residual (nonlinear function value) at the final solution
71: Logically Collective
73: Input Parameters:
74: + snes - the shell `SNES`
75: - flg - `PETSC_TRUE` to always compute the residual
77: Level: advanced
79: Note:
80: Some solvers (such as smoothers in a `SNESFAS`) do not need the residual computed at the final solution so skip computing it
81: to save time.
83: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSolve()`, `SNESGetAlwaysComputesFinalResidual()`
84: @*/
85: PetscErrorCode SNESSetAlwaysComputesFinalResidual(SNES snes, PetscBool flg)
86: {
87: PetscFunctionBegin;
89: snes->alwayscomputesfinalresidual = flg;
90: PetscFunctionReturn(PETSC_SUCCESS);
91: }
93: /*@
94: SNESGetAlwaysComputesFinalResidual - checks if the `SNES` always computes the residual at the final solution
96: Logically Collective
98: Input Parameter:
99: . snes - the `SNES` context
101: Output Parameter:
102: . flg - `PETSC_TRUE` if the residual is computed
104: Level: advanced
106: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSolve()`, `SNESSetAlwaysComputesFinalResidual()`
107: @*/
108: PetscErrorCode SNESGetAlwaysComputesFinalResidual(SNES snes, PetscBool *flg)
109: {
110: PetscFunctionBegin;
112: *flg = snes->alwayscomputesfinalresidual;
113: PetscFunctionReturn(PETSC_SUCCESS);
114: }
116: /*@
117: SNESSetFunctionDomainError - tells `SNES` that the input vector, a proposed new solution, to your function you provided to `SNESSetFunction()` is not
118: in the functions domain. For example, a step with negative pressure.
120: Not Collective
122: Input Parameter:
123: . snes - the `SNES` context
125: Level: advanced
127: Notes:
128: This does not need to be called by all processes in the `SNES` MPI communicator.
130: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
132: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
134: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
135: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
137: You can call `SNESSetJacobianDomainError()` during a Jacobian computation to indicate the proposed solution is not in the domain.
139: Developer Note:
140: This value is used by `SNESCheckFunctionNorm()` to determine if the `SNESConvergedReason` is set to `SNES_DIVERGED_FUNCTION_DOMAIN`
142: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetJacobianDomainError()`, `SNESVISetVariableBounds()`,
143: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`,
144: `SNES_DIVERGED_FUNCTION_DOMAIN`
145: @*/
146: PetscErrorCode SNESSetFunctionDomainError(SNES snes)
147: {
148: PetscFunctionBegin;
150: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates input vector is not in the function domain");
151: snes->domainerror = PETSC_TRUE;
152: PetscFunctionReturn(PETSC_SUCCESS);
153: }
155: /*@
156: SNESSetJacobianDomainError - tells `SNES` that the function you provided to `SNESSetJacobian()` at the proposed step. For example there is a negative element transformation.
158: Logically Collective
160: Input Parameter:
161: . snes - the `SNES` context
163: Level: advanced
165: Notes:
166: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
168: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
170: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
171: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
173: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESVISetVariableBounds()`,
174: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`
175: @*/
176: PetscErrorCode SNESSetJacobianDomainError(SNES snes)
177: {
178: PetscFunctionBegin;
180: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates computeJacobian does not make sense");
181: snes->jacobiandomainerror = PETSC_TRUE;
182: PetscFunctionReturn(PETSC_SUCCESS);
183: }
185: /*@
186: SNESSetCheckJacobianDomainError - tells `SNESSolve()` whether to check if the user called `SNESSetJacobianDomainError()` Jacobian domain error after
187: each Jacobian evaluation. By default, it checks for the Jacobian domain error in the debug mode, and does not check it in the optimized mode.
189: Logically Collective
191: Input Parameters:
192: + snes - the `SNES` context
193: - flg - indicates if or not to check Jacobian domain error after each Jacobian evaluation
195: Level: advanced
197: Note:
198: Checks require one extra parallel synchronization for each Jacobian evaluation
200: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESGetCheckJacobianDomainError()`
201: @*/
202: PetscErrorCode SNESSetCheckJacobianDomainError(SNES snes, PetscBool flg)
203: {
204: PetscFunctionBegin;
206: snes->checkjacdomainerror = flg;
207: PetscFunctionReturn(PETSC_SUCCESS);
208: }
210: /*@
211: SNESGetCheckJacobianDomainError - Get an indicator whether or not `SNES` is checking Jacobian domain errors after each Jacobian evaluation.
213: Logically Collective
215: Input Parameter:
216: . snes - the `SNES` context
218: Output Parameter:
219: . flg - `PETSC_FALSE` indicates that it is not checking Jacobian domain errors after each Jacobian evaluation
221: Level: advanced
223: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESSetCheckJacobianDomainError()`
224: @*/
225: PetscErrorCode SNESGetCheckJacobianDomainError(SNES snes, PetscBool *flg)
226: {
227: PetscFunctionBegin;
229: PetscAssertPointer(flg, 2);
230: *flg = snes->checkjacdomainerror;
231: PetscFunctionReturn(PETSC_SUCCESS);
232: }
234: /*@
235: SNESGetFunctionDomainError - Gets the status of the domain error after a call to `SNESComputeFunction()`
237: Not Collective, different MPI processes may return different values
239: Input Parameter:
240: . snes - the `SNES` context
242: Output Parameter:
243: . domainerror - Set to `PETSC_TRUE` if there's a domain error; `PETSC_FALSE` otherwise.
245: Level: developer
247: Notes:
248: The value will only be true on those MPI processes that called `SNESSetFunctionDomainError()`
250: The value is reset to `PETSC_FALSE` when `SNESCheckFunctionNorm()` is called.
252: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`
253: @*/
254: PetscErrorCode SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
255: {
256: PetscFunctionBegin;
258: PetscAssertPointer(domainerror, 2);
259: *domainerror = snes->domainerror;
260: PetscFunctionReturn(PETSC_SUCCESS);
261: }
263: /*@
264: SNESGetJacobianDomainError - Gets the status of the Jacobian domain error after a call to `SNESComputeJacobian()`
266: Not Collective, different MPI processes may return different values
268: Input Parameter:
269: . snes - the `SNES` context
271: Output Parameter:
272: . domainerror - Set to `PETSC_TRUE` if there's a Jacobian domain error; `PETSC_FALSE` otherwise.
274: Level: advanced
276: Notes:
277: The value will only be true on those MPI processes that called `SNESSetJacobianDomainError()`
279: The value is reset to `PETSC_FALSE` when `SNESCheckJacobianDomainerror()` is called but only `SNESSetCheckJacobianDomainError()` was called
281: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`, `SNESGetFunctionDomainError()`
282: @*/
283: PetscErrorCode SNESGetJacobianDomainError(SNES snes, PetscBool *domainerror)
284: {
285: PetscFunctionBegin;
287: PetscAssertPointer(domainerror, 2);
288: *domainerror = snes->jacobiandomainerror;
289: PetscFunctionReturn(PETSC_SUCCESS);
290: }
292: /*@
293: SNESLoad - Loads a `SNES` that has been stored in `PETSCVIEWERBINARY` with `SNESView()`.
295: Collective
297: Input Parameters:
298: + snes - the newly loaded `SNES`, this needs to have been created with `SNESCreate()` or
299: some related function before a call to `SNESLoad()`.
300: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()`
302: Level: intermediate
304: Note:
305: The `SNESType` is determined by the data in the file, any type set into the `SNES` before this call is ignored.
307: .seealso: [](ch_snes), `SNES`, `PetscViewer`, `SNESCreate()`, `SNESType`, `PetscViewerBinaryOpen()`, `SNESView()`, `MatLoad()`, `VecLoad()`
308: @*/
309: PetscErrorCode SNESLoad(SNES snes, PetscViewer viewer)
310: {
311: PetscBool isbinary;
312: PetscInt classid;
313: char type[256];
314: KSP ksp;
315: DM dm;
316: DMSNES dmsnes;
318: PetscFunctionBegin;
321: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
322: PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
324: PetscCall(PetscViewerBinaryRead(viewer, &classid, 1, NULL, PETSC_INT));
325: PetscCheck(classid == SNES_FILE_CLASSID, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Not SNES next in file");
326: PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
327: PetscCall(SNESSetType(snes, type));
328: PetscTryTypeMethod(snes, load, viewer);
329: PetscCall(SNESGetDM(snes, &dm));
330: PetscCall(DMGetDMSNES(dm, &dmsnes));
331: PetscCall(DMSNESLoad(dmsnes, viewer));
332: PetscCall(SNESGetKSP(snes, &ksp));
333: PetscCall(KSPLoad(ksp, viewer));
334: PetscFunctionReturn(PETSC_SUCCESS);
335: }
337: #include <petscdraw.h>
338: #if defined(PETSC_HAVE_SAWS)
339: #include <petscviewersaws.h>
340: #endif
342: /*@
343: SNESViewFromOptions - View a `SNES` based on values in the options database
345: Collective
347: Input Parameters:
348: + A - the `SNES` context
349: . obj - Optional object that provides the options prefix for the checks
350: - name - command line option
352: Level: intermediate
354: .seealso: [](ch_snes), `SNES`, `SNESView`, `PetscObjectViewFromOptions()`, `SNESCreate()`
355: @*/
356: PetscErrorCode SNESViewFromOptions(SNES A, PetscObject obj, const char name[])
357: {
358: PetscFunctionBegin;
360: PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
361: PetscFunctionReturn(PETSC_SUCCESS);
362: }
364: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES, Vec, Mat, Mat, void *);
366: /*@
367: SNESView - Prints or visualizes the `SNES` data structure.
369: Collective
371: Input Parameters:
372: + snes - the `SNES` context
373: - viewer - the `PetscViewer`
375: Options Database Key:
376: . -snes_view - Calls `SNESView()` at end of `SNESSolve()`
378: Level: beginner
380: Notes:
381: The available visualization contexts include
382: + `PETSC_VIEWER_STDOUT_SELF` - standard output (default)
383: - `PETSC_VIEWER_STDOUT_WORLD` - synchronized standard
384: output where only the first processor opens
385: the file. All other processors send their
386: data to the first processor to print.
388: The available formats include
389: + `PETSC_VIEWER_DEFAULT` - standard output (default)
390: - `PETSC_VIEWER_ASCII_INFO_DETAIL` - more verbose output for `SNESNASM`
392: The user can open an alternative visualization context with
393: `PetscViewerASCIIOpen()` - output to a specified file.
395: In the debugger you can do "call `SNESView`(snes,0)" to display the `SNES` solver. (The same holds for any PETSc object viewer).
397: .seealso: [](ch_snes), `SNES`, `SNESLoad()`, `SNESCreate()`, `PetscViewerASCIIOpen()`
398: @*/
399: PetscErrorCode SNESView(SNES snes, PetscViewer viewer)
400: {
401: SNESKSPEW *kctx;
402: KSP ksp;
403: SNESLineSearch linesearch;
404: PetscBool isascii, isstring, isbinary, isdraw;
405: DMSNES dmsnes;
406: #if defined(PETSC_HAVE_SAWS)
407: PetscBool issaws;
408: #endif
410: PetscFunctionBegin;
412: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &viewer));
414: PetscCheckSameComm(snes, 1, viewer, 2);
416: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii));
417: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
418: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
419: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
420: #if defined(PETSC_HAVE_SAWS)
421: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
422: #endif
423: if (isascii) {
424: SNESNormSchedule normschedule;
425: DM dm;
426: SNESJacobianFn *cJ;
427: void *ctx;
428: const char *pre = "";
430: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)snes, viewer));
431: if (!snes->setupcalled) PetscCall(PetscViewerASCIIPrintf(viewer, " SNES has not been set up so information may be incomplete\n"));
432: if (snes->ops->view) {
433: PetscCall(PetscViewerASCIIPushTab(viewer));
434: PetscUseTypeMethod(snes, view, viewer);
435: PetscCall(PetscViewerASCIIPopTab(viewer));
436: }
437: if (snes->max_funcs == PETSC_UNLIMITED) {
438: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=unlimited\n", snes->max_its));
439: } else {
440: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=%" PetscInt_FMT "\n", snes->max_its, snes->max_funcs));
441: }
442: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%g, absolute=%g, solution=%g\n", (double)snes->rtol, (double)snes->abstol, (double)snes->stol));
443: if (snes->usesksp) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of linear solver iterations=%" PetscInt_FMT "\n", snes->linear_its));
444: PetscCall(PetscViewerASCIIPrintf(viewer, " total number of function evaluations=%" PetscInt_FMT "\n", snes->nfuncs));
445: PetscCall(SNESGetNormSchedule(snes, &normschedule));
446: if (normschedule > 0) PetscCall(PetscViewerASCIIPrintf(viewer, " norm schedule %s\n", SNESNormSchedules[normschedule]));
447: if (snes->gridsequence) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of grid sequence refinements=%" PetscInt_FMT "\n", snes->gridsequence));
448: if (snes->ksp_ewconv) {
449: kctx = (SNESKSPEW *)snes->kspconvctx;
450: if (kctx) {
451: PetscCall(PetscViewerASCIIPrintf(viewer, " Eisenstat-Walker computation of KSP relative tolerance (version %" PetscInt_FMT ")\n", kctx->version));
452: PetscCall(PetscViewerASCIIPrintf(viewer, " rtol_0=%g, rtol_max=%g, threshold=%g\n", (double)kctx->rtol_0, (double)kctx->rtol_max, (double)kctx->threshold));
453: PetscCall(PetscViewerASCIIPrintf(viewer, " gamma=%g, alpha=%g, alpha2=%g\n", (double)kctx->gamma, (double)kctx->alpha, (double)kctx->alpha2));
454: }
455: }
456: if (snes->lagpreconditioner == -1) {
457: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is never rebuilt\n"));
458: } else if (snes->lagpreconditioner > 1) {
459: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is rebuilt every %" PetscInt_FMT " new Jacobians\n", snes->lagpreconditioner));
460: }
461: if (snes->lagjacobian == -1) {
462: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is never rebuilt\n"));
463: } else if (snes->lagjacobian > 1) {
464: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is rebuilt every %" PetscInt_FMT " SNES iterations\n", snes->lagjacobian));
465: }
466: PetscCall(SNESGetDM(snes, &dm));
467: PetscCall(DMSNESGetJacobian(dm, &cJ, &ctx));
468: if (snes->mf_operator) {
469: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing\n"));
470: pre = "Preconditioning ";
471: }
472: if (cJ == SNESComputeJacobianDefault) {
473: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences one column at a time\n", pre));
474: } else if (cJ == SNESComputeJacobianDefaultColor) {
475: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences with coloring\n", pre));
476: /* it slightly breaks data encapsulation for access the DMDA information directly */
477: } else if (cJ == SNESComputeJacobian_DMDA) {
478: MatFDColoring fdcoloring;
479: PetscCall(PetscObjectQuery((PetscObject)dm, "DMDASNES_FDCOLORING", (PetscObject *)&fdcoloring));
480: if (fdcoloring) {
481: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using colored finite differences on a DMDA\n", pre));
482: } else {
483: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using a DMDA local Jacobian\n", pre));
484: }
485: } else if (snes->mf && !snes->mf_operator) {
486: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing, no explicit Jacobian\n"));
487: }
488: } else if (isstring) {
489: const char *type;
490: PetscCall(SNESGetType(snes, &type));
491: PetscCall(PetscViewerStringSPrintf(viewer, " SNESType: %-7.7s", type));
492: PetscTryTypeMethod(snes, view, viewer);
493: } else if (isbinary) {
494: PetscInt classid = SNES_FILE_CLASSID;
495: MPI_Comm comm;
496: PetscMPIInt rank;
497: char type[256];
499: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
500: PetscCallMPI(MPI_Comm_rank(comm, &rank));
501: if (rank == 0) {
502: PetscCall(PetscViewerBinaryWrite(viewer, &classid, 1, PETSC_INT));
503: PetscCall(PetscStrncpy(type, ((PetscObject)snes)->type_name, sizeof(type)));
504: PetscCall(PetscViewerBinaryWrite(viewer, type, sizeof(type), PETSC_CHAR));
505: }
506: PetscTryTypeMethod(snes, view, viewer);
507: } else if (isdraw) {
508: PetscDraw draw;
509: char str[36];
510: PetscReal x, y, bottom, h;
512: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
513: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
514: PetscCall(PetscStrncpy(str, "SNES: ", sizeof(str)));
515: PetscCall(PetscStrlcat(str, ((PetscObject)snes)->type_name, sizeof(str)));
516: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_BLUE, PETSC_DRAW_BLACK, str, NULL, &h));
517: bottom = y - h;
518: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
519: PetscTryTypeMethod(snes, view, viewer);
520: #if defined(PETSC_HAVE_SAWS)
521: } else if (issaws) {
522: PetscMPIInt rank;
523: const char *name;
525: PetscCall(PetscObjectGetName((PetscObject)snes, &name));
526: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
527: if (!((PetscObject)snes)->amsmem && rank == 0) {
528: char dir[1024];
530: PetscCall(PetscObjectViewSAWs((PetscObject)snes, viewer));
531: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/its", name));
532: PetscCallSAWs(SAWs_Register, (dir, &snes->iter, 1, SAWs_READ, SAWs_INT));
533: if (!snes->conv_hist) PetscCall(SNESSetConvergenceHistory(snes, NULL, NULL, PETSC_DECIDE, PETSC_TRUE));
534: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/conv_hist", name));
535: PetscCallSAWs(SAWs_Register, (dir, snes->conv_hist, 10, SAWs_READ, SAWs_DOUBLE));
536: }
537: #endif
538: }
539: if (snes->linesearch) {
540: PetscCall(SNESGetLineSearch(snes, &linesearch));
541: PetscCall(PetscViewerASCIIPushTab(viewer));
542: PetscCall(SNESLineSearchView(linesearch, viewer));
543: PetscCall(PetscViewerASCIIPopTab(viewer));
544: }
545: if (snes->npc && snes->usesnpc) {
546: PetscCall(PetscViewerASCIIPushTab(viewer));
547: PetscCall(SNESView(snes->npc, viewer));
548: PetscCall(PetscViewerASCIIPopTab(viewer));
549: }
550: PetscCall(PetscViewerASCIIPushTab(viewer));
551: PetscCall(DMGetDMSNES(snes->dm, &dmsnes));
552: PetscCall(DMSNESView(dmsnes, viewer));
553: PetscCall(PetscViewerASCIIPopTab(viewer));
554: if (snes->usesksp) {
555: PetscCall(SNESGetKSP(snes, &ksp));
556: PetscCall(PetscViewerASCIIPushTab(viewer));
557: PetscCall(KSPView(ksp, viewer));
558: PetscCall(PetscViewerASCIIPopTab(viewer));
559: }
560: if (isdraw) {
561: PetscDraw draw;
562: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
563: PetscCall(PetscDrawPopCurrentPoint(draw));
564: }
565: PetscFunctionReturn(PETSC_SUCCESS);
566: }
568: /*
569: We retain a list of functions that also take SNES command
570: line options. These are called at the end SNESSetFromOptions()
571: */
572: #define MAXSETFROMOPTIONS 5
573: static PetscInt numberofsetfromoptions;
574: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);
576: /*@C
577: SNESAddOptionsChecker - Adds an additional function to check for `SNES` options.
579: Not Collective
581: Input Parameter:
582: . snescheck - function that checks for options
584: Calling sequence of `snescheck`:
585: . snes - the `SNES` object for which it is checking options
587: Level: developer
589: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`
590: @*/
591: PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES snes))
592: {
593: PetscFunctionBegin;
594: PetscCheck(numberofsetfromoptions < MAXSETFROMOPTIONS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %d allowed", MAXSETFROMOPTIONS);
595: othersetfromoptions[numberofsetfromoptions++] = snescheck;
596: PetscFunctionReturn(PETSC_SUCCESS);
597: }
599: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
600: {
601: Mat J;
602: MatNullSpace nullsp;
604: PetscFunctionBegin;
607: if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
608: Mat A = snes->jacobian, B = snes->jacobian_pre;
609: PetscCall(MatCreateVecs(A ? A : B, NULL, &snes->vec_func));
610: }
612: PetscCheck(version == 1 || version == 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator routines, only version 1 and 2");
613: if (version == 1) {
614: PetscCall(MatCreateSNESMF(snes, &J));
615: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
616: PetscCall(MatSetFromOptions(J));
617: /* TODO: the version 2 code should be merged into the MatCreateSNESMF() and MatCreateMFFD() infrastructure and then removed */
618: } else /* if (version == 2) */ {
619: PetscCheck(snes->vec_func, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "SNESSetFunction() must be called first");
620: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
621: PetscCall(MatCreateSNESMFMore(snes, snes->vec_func, &J));
622: #else
623: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "matrix-free operator routines (version 2)");
624: #endif
625: }
627: /* attach any user provided null space that was on Amat to the newly created matrix-free matrix */
628: if (snes->jacobian) {
629: PetscCall(MatGetNullSpace(snes->jacobian, &nullsp));
630: if (nullsp) PetscCall(MatSetNullSpace(J, nullsp));
631: }
633: PetscCall(PetscInfo(snes, "Setting default matrix-free operator routines (version %" PetscInt_FMT ")\n", version));
634: if (hasOperator) {
635: /* This version replaces the user provided Jacobian matrix with a
636: matrix-free version but still employs the user-provided matrix used for computing the preconditioner. */
637: PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
638: } else {
639: /* This version replaces both the user-provided Jacobian and the user-
640: provided preconditioner Jacobian with the default matrix-free version. */
641: if (snes->npcside == PC_LEFT && snes->npc) {
642: if (!snes->jacobian) PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
643: } else {
644: KSP ksp;
645: PC pc;
646: PetscBool match;
648: PetscCall(SNESSetJacobian(snes, J, J, MatMFFDComputeJacobian, NULL));
649: /* Force no preconditioner */
650: PetscCall(SNESGetKSP(snes, &ksp));
651: PetscCall(KSPGetPC(ksp, &pc));
652: PetscCall(PetscObjectTypeCompareAny((PetscObject)pc, &match, PCSHELL, PCH2OPUS, ""));
653: if (!match) {
654: PetscCall(PetscInfo(snes, "Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n"));
655: PetscCall(PCSetType(pc, PCNONE));
656: }
657: }
658: }
659: PetscCall(MatDestroy(&J));
660: PetscFunctionReturn(PETSC_SUCCESS);
661: }
663: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine, Mat Restrict, Vec Rscale, Mat Inject, DM dmcoarse, void *ctx)
664: {
665: SNES snes = (SNES)ctx;
666: Vec Xfine, Xfine_named = NULL, Xcoarse;
668: PetscFunctionBegin;
669: if (PetscLogPrintInfo) {
670: PetscInt finelevel, coarselevel, fineclevel, coarseclevel;
671: PetscCall(DMGetRefineLevel(dmfine, &finelevel));
672: PetscCall(DMGetCoarsenLevel(dmfine, &fineclevel));
673: PetscCall(DMGetRefineLevel(dmcoarse, &coarselevel));
674: PetscCall(DMGetCoarsenLevel(dmcoarse, &coarseclevel));
675: PetscCall(PetscInfo(dmfine, "Restricting SNES solution vector from level %" PetscInt_FMT "-%" PetscInt_FMT " to level %" PetscInt_FMT "-%" PetscInt_FMT "\n", finelevel, fineclevel, coarselevel, coarseclevel));
676: }
677: if (dmfine == snes->dm) Xfine = snes->vec_sol;
678: else {
679: PetscCall(DMGetNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
680: Xfine = Xfine_named;
681: }
682: PetscCall(DMGetNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
683: if (Inject) {
684: PetscCall(MatRestrict(Inject, Xfine, Xcoarse));
685: } else {
686: PetscCall(MatRestrict(Restrict, Xfine, Xcoarse));
687: PetscCall(VecPointwiseMult(Xcoarse, Xcoarse, Rscale));
688: }
689: PetscCall(DMRestoreNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
690: if (Xfine_named) PetscCall(DMRestoreNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
691: PetscFunctionReturn(PETSC_SUCCESS);
692: }
694: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm, DM dmc, void *ctx)
695: {
696: PetscFunctionBegin;
697: PetscCall(DMCoarsenHookAdd(dmc, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, ctx));
698: PetscFunctionReturn(PETSC_SUCCESS);
699: }
701: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
702: * safely call SNESGetDM() in their residual evaluation routine. */
703: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp, Mat A, Mat B, void *ctx)
704: {
705: SNES snes = (SNES)ctx;
706: DMSNES sdm;
707: Vec X, Xnamed = NULL;
708: DM dmsave;
709: void *ctxsave;
710: SNESJacobianFn *jac = NULL;
712: PetscFunctionBegin;
713: dmsave = snes->dm;
714: PetscCall(KSPGetDM(ksp, &snes->dm));
715: if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
716: else {
717: PetscBool has;
719: /* We are on a coarser level, this vec was initialized using a DM restrict hook */
720: PetscCall(DMHasNamedGlobalVector(snes->dm, "SNESVecSol", &has));
721: PetscCheck(has, PetscObjectComm((PetscObject)snes->dm), PETSC_ERR_PLIB, "Missing SNESVecSol");
722: PetscCall(DMGetNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
723: X = Xnamed;
724: PetscCall(SNESGetJacobian(snes, NULL, NULL, &jac, &ctxsave));
725: /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
726: if (jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, SNESComputeJacobianDefaultColor, NULL));
727: }
729: /* Compute the operators */
730: PetscCall(DMGetDMSNES(snes->dm, &sdm));
731: if (Xnamed && sdm->ops->computefunction) {
732: /* The SNES contract with the user is that ComputeFunction is always called before ComputeJacobian.
733: We make sure of this here. Disable affine shift since it is for the finest level */
734: Vec F, saverhs = snes->vec_rhs;
736: snes->vec_rhs = NULL;
737: PetscCall(DMGetGlobalVector(snes->dm, &F));
738: PetscCall(SNESComputeFunction(snes, X, F));
739: PetscCall(DMRestoreGlobalVector(snes->dm, &F));
740: snes->vec_rhs = saverhs;
741: snes->nfuncs--; /* Do not log coarser level evaluations */
742: }
743: /* Make sure KSP DM has the Jacobian computation routine */
744: if (!sdm->ops->computejacobian) PetscCall(DMCopyDMSNES(dmsave, snes->dm));
745: PetscCall(SNESComputeJacobian(snes, X, A, B));
747: /* Put the previous context back */
748: if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, jac, ctxsave));
750: if (Xnamed) PetscCall(DMRestoreNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
751: snes->dm = dmsave;
752: PetscFunctionReturn(PETSC_SUCCESS);
753: }
755: /*@
756: SNESSetUpMatrices - ensures that matrices are available for `SNES` Newton-like methods, this is called by `SNESSetUp_XXX()`
758: Collective
760: Input Parameter:
761: . snes - `SNES` object to configure
763: Level: developer
765: Note:
766: If the matrices do not yet exist it attempts to create them based on options previously set for the `SNES` such as `-snes_mf`
768: Developer Note:
769: The functionality of this routine overlaps in a confusing way with the functionality of `SNESSetUpMatrixFree_Private()` which is called by
770: `SNESSetUp()` but sometimes `SNESSetUpMatrices()` is called without `SNESSetUp()` being called. A refactorization to simplify the
771: logic that handles the matrix-free case is desirable.
773: .seealso: [](ch_snes), `SNES`, `SNESSetUp()`
774: @*/
775: PetscErrorCode SNESSetUpMatrices(SNES snes)
776: {
777: DM dm;
778: DMSNES sdm;
780: PetscFunctionBegin;
781: PetscCall(SNESGetDM(snes, &dm));
782: PetscCall(DMGetDMSNES(dm, &sdm));
783: if (!snes->jacobian && snes->mf && !snes->mf_operator && !snes->jacobian_pre) {
784: Mat J;
785: void *functx;
786: PetscCall(MatCreateSNESMF(snes, &J));
787: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
788: PetscCall(MatSetFromOptions(J));
789: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
790: PetscCall(SNESSetJacobian(snes, J, J, NULL, NULL));
791: PetscCall(MatDestroy(&J));
792: } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
793: Mat J, B;
794: PetscCall(MatCreateSNESMF(snes, &J));
795: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
796: PetscCall(MatSetFromOptions(J));
797: PetscCall(DMCreateMatrix(snes->dm, &B));
798: /* sdm->computejacobian was already set to reach here */
799: PetscCall(SNESSetJacobian(snes, J, B, NULL, NULL));
800: PetscCall(MatDestroy(&J));
801: PetscCall(MatDestroy(&B));
802: } else if (!snes->jacobian_pre) {
803: PetscDS prob;
804: Mat J, B;
805: PetscBool hasPrec = PETSC_FALSE;
807: J = snes->jacobian;
808: PetscCall(DMGetDS(dm, &prob));
809: if (prob) PetscCall(PetscDSHasJacobianPreconditioner(prob, &hasPrec));
810: if (J) PetscCall(PetscObjectReference((PetscObject)J));
811: else if (hasPrec) PetscCall(DMCreateMatrix(snes->dm, &J));
812: PetscCall(DMCreateMatrix(snes->dm, &B));
813: PetscCall(SNESSetJacobian(snes, J ? J : B, B, NULL, NULL));
814: PetscCall(MatDestroy(&J));
815: PetscCall(MatDestroy(&B));
816: }
817: {
818: KSP ksp;
819: PetscCall(SNESGetKSP(snes, &ksp));
820: PetscCall(KSPSetComputeOperators(ksp, KSPComputeOperators_SNES, snes));
821: PetscCall(DMCoarsenHookAdd(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
822: }
823: PetscFunctionReturn(PETSC_SUCCESS);
824: }
826: PETSC_SINGLE_LIBRARY_INTERN PetscErrorCode PetscMonitorPauseFinal_Internal(PetscInt, void *);
828: static PetscErrorCode SNESMonitorPauseFinal_Internal(SNES snes)
829: {
830: PetscFunctionBegin;
831: if (!snes->pauseFinal) PetscFunctionReturn(PETSC_SUCCESS);
832: PetscCall(PetscMonitorPauseFinal_Internal(snes->numbermonitors, snes->monitorcontext));
833: PetscFunctionReturn(PETSC_SUCCESS);
834: }
836: /*@C
837: SNESMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user
839: Collective
841: Input Parameters:
842: + snes - `SNES` object you wish to monitor
843: . name - the monitor type one is seeking
844: . help - message indicating what monitoring is done
845: . manual - manual page for the monitor
846: . monitor - the monitor function, this must use a `PetscViewerFormat` as its context
847: - monitorsetup - a function that is called once ONLY if the user selected this monitor that may set additional features of the `SNES` or `PetscViewer` objects
849: Calling sequence of `monitor`:
850: + snes - the nonlinear solver context
851: . it - the current iteration
852: . r - the current function norm
853: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
855: Calling sequence of `monitorsetup`:
856: + snes - the nonlinear solver context
857: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
859: Options Database Key:
860: . -name - trigger the use of this monitor in `SNESSetFromOptions()`
862: Level: advanced
864: .seealso: [](ch_snes), `PetscOptionsCreateViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
865: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`
866: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
867: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
868: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
869: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
870: `PetscOptionsFList()`, `PetscOptionsEList()`
871: @*/
872: PetscErrorCode SNESMonitorSetFromOptions(SNES snes, const char name[], const char help[], const char manual[], PetscErrorCode (*monitor)(SNES snes, PetscInt it, PetscReal r, PetscViewerAndFormat *vf), PetscErrorCode (*monitorsetup)(SNES snes, PetscViewerAndFormat *vf))
873: {
874: PetscViewer viewer;
875: PetscViewerFormat format;
876: PetscBool flg;
878: PetscFunctionBegin;
879: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, name, &viewer, &format, &flg));
880: if (flg) {
881: PetscViewerAndFormat *vf;
882: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
883: PetscCall(PetscViewerDestroy(&viewer));
884: if (monitorsetup) PetscCall((*monitorsetup)(snes, vf));
885: PetscCall(SNESMonitorSet(snes, (PetscErrorCode (*)(SNES, PetscInt, PetscReal, void *))monitor, vf, (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy));
886: }
887: PetscFunctionReturn(PETSC_SUCCESS);
888: }
890: PetscErrorCode SNESEWSetFromOptions_Private(SNESKSPEW *kctx, PetscBool print_api, MPI_Comm comm, const char *prefix)
891: {
892: const char *api = print_api ? "SNESKSPSetParametersEW" : NULL;
894: PetscFunctionBegin;
895: PetscOptionsBegin(comm, prefix, "Eisenstat and Walker type forcing options", "KSP");
896: PetscCall(PetscOptionsInt("-ksp_ew_version", "Version 1, 2 or 3", api, kctx->version, &kctx->version, NULL));
897: PetscCall(PetscOptionsReal("-ksp_ew_rtol0", "0 <= rtol0 < 1", api, kctx->rtol_0, &kctx->rtol_0, NULL));
898: kctx->rtol_max = PetscMax(kctx->rtol_0, kctx->rtol_max);
899: PetscCall(PetscOptionsReal("-ksp_ew_rtolmax", "0 <= rtolmax < 1", api, kctx->rtol_max, &kctx->rtol_max, NULL));
900: PetscCall(PetscOptionsReal("-ksp_ew_gamma", "0 <= gamma <= 1", api, kctx->gamma, &kctx->gamma, NULL));
901: PetscCall(PetscOptionsReal("-ksp_ew_alpha", "1 < alpha <= 2", api, kctx->alpha, &kctx->alpha, NULL));
902: PetscCall(PetscOptionsReal("-ksp_ew_alpha2", "alpha2", NULL, kctx->alpha2, &kctx->alpha2, NULL));
903: PetscCall(PetscOptionsReal("-ksp_ew_threshold", "0 < threshold < 1", api, kctx->threshold, &kctx->threshold, NULL));
904: PetscCall(PetscOptionsReal("-ksp_ew_v4_p1", "p1", NULL, kctx->v4_p1, &kctx->v4_p1, NULL));
905: PetscCall(PetscOptionsReal("-ksp_ew_v4_p2", "p2", NULL, kctx->v4_p2, &kctx->v4_p2, NULL));
906: PetscCall(PetscOptionsReal("-ksp_ew_v4_p3", "p3", NULL, kctx->v4_p3, &kctx->v4_p3, NULL));
907: PetscCall(PetscOptionsReal("-ksp_ew_v4_m1", "Scaling when rk-1 in [p2,p3)", NULL, kctx->v4_m1, &kctx->v4_m1, NULL));
908: PetscCall(PetscOptionsReal("-ksp_ew_v4_m2", "Scaling when rk-1 in [p3,+infty)", NULL, kctx->v4_m2, &kctx->v4_m2, NULL));
909: PetscCall(PetscOptionsReal("-ksp_ew_v4_m3", "Threshold for successive rtol (0.1 in Eq.7)", NULL, kctx->v4_m3, &kctx->v4_m3, NULL));
910: PetscCall(PetscOptionsReal("-ksp_ew_v4_m4", "Adaptation scaling (0.5 in Eq.7)", NULL, kctx->v4_m4, &kctx->v4_m4, NULL));
911: PetscOptionsEnd();
912: PetscFunctionReturn(PETSC_SUCCESS);
913: }
915: /*@
916: SNESSetFromOptions - Sets various `SNES` and `KSP` parameters from user options.
918: Collective
920: Input Parameter:
921: . snes - the `SNES` context
923: Options Database Keys:
924: + -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, `SNESType` for complete list
925: . -snes_rtol <rtol> - relative decrease in tolerance norm from initial
926: . -snes_atol <abstol> - absolute tolerance of residual norm
927: . -snes_stol <stol> - convergence tolerance in terms of the norm of the change in the solution between steps
928: . -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
929: . -snes_max_it <max_it> - maximum number of iterations
930: . -snes_max_funcs <max_funcs> - maximum number of function evaluations
931: . -snes_force_iteration <force> - force `SNESSolve()` to take at least one iteration
932: . -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
933: . -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
934: . -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
935: . -snes_lag_preconditioner_persists <true,false> - retains the -snes_lag_preconditioner information across multiple SNESSolve()
936: . -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
937: . -snes_lag_jacobian_persists <true,false> - retains the -snes_lag_jacobian information across multiple SNESSolve()
938: . -snes_convergence_test <default,skip,correct_pressure> - convergence test in nonlinear solver. default `SNESConvergedDefault()`. skip `SNESConvergedSkip()` means continue iterating until max_it or some other criterion is reached, saving expense of convergence test. correct_pressure `SNESConvergedCorrectPressure()` has special handling of a pressure null space.
939: . -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
940: . -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
941: . -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
942: . -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
943: . -snes_monitor_lg_residualnorm - plots residual norm at each iteration
944: . -snes_monitor_lg_range - plots residual norm at each iteration
945: . -snes_monitor_pause_final - Pauses all monitor drawing after the solver ends
946: . -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
947: . -snes_fd_color - use finite differences with coloring to compute Jacobian
948: . -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each `KSP` iteration
949: . -snes_converged_reason - print the reason for convergence/divergence after each solve
950: . -npc_snes_type <type> - the `SNES` type to use as a nonlinear preconditioner
951: . -snes_test_jacobian <optional threshold> - compare the user provided Jacobian with one computed via finite differences to check for errors. If a threshold is given, display only those entries whose difference is greater than the threshold.
952: - -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference between them to help users detect the location of errors in the user provided Jacobian.
954: Options Database Keys for Eisenstat-Walker method:
955: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
956: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
957: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
958: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
959: . -snes_ksp_ew_gamma <gamma> - Sets gamma
960: . -snes_ksp_ew_alpha <alpha> - Sets alpha
961: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
962: - -snes_ksp_ew_threshold <threshold> - Sets threshold
964: Level: beginner
966: Notes:
967: To see all options, run your program with the -help option or consult the users manual
969: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
970: and computing explicitly with
971: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
973: .seealso: [](ch_snes), `SNESType`, `SNESSetOptionsPrefix()`, `SNESResetFromOptions()`, `SNES`, `SNESCreate()`, `MatCreateSNESMF()`, `MatFDColoring`
974: @*/
975: PetscErrorCode SNESSetFromOptions(SNES snes)
976: {
977: PetscBool flg, pcset, persist, set;
978: PetscInt i, indx, lag, grids, max_its, max_funcs;
979: const char *deft = SNESNEWTONLS;
980: const char *convtests[] = {"default", "skip", "correct_pressure"};
981: SNESKSPEW *kctx = NULL;
982: char type[256], monfilename[PETSC_MAX_PATH_LEN], ewprefix[256];
983: PCSide pcside;
984: const char *optionsprefix;
985: PetscReal rtol, abstol, stol;
987: PetscFunctionBegin;
989: PetscCall(SNESRegisterAll());
990: PetscObjectOptionsBegin((PetscObject)snes);
991: if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
992: PetscCall(PetscOptionsFList("-snes_type", "Nonlinear solver method", "SNESSetType", SNESList, deft, type, 256, &flg));
993: if (flg) {
994: PetscCall(SNESSetType(snes, type));
995: } else if (!((PetscObject)snes)->type_name) {
996: PetscCall(SNESSetType(snes, deft));
997: }
999: abstol = snes->abstol;
1000: rtol = snes->rtol;
1001: stol = snes->stol;
1002: max_its = snes->max_its;
1003: max_funcs = snes->max_funcs;
1004: PetscCall(PetscOptionsReal("-snes_rtol", "Stop if decrease in function norm less than", "SNESSetTolerances", snes->rtol, &rtol, NULL));
1005: PetscCall(PetscOptionsReal("-snes_atol", "Stop if function norm less than", "SNESSetTolerances", snes->abstol, &abstol, NULL));
1006: PetscCall(PetscOptionsReal("-snes_stol", "Stop if step length less than", "SNESSetTolerances", snes->stol, &stol, NULL));
1007: PetscCall(PetscOptionsInt("-snes_max_it", "Maximum iterations", "SNESSetTolerances", snes->max_its, &max_its, NULL));
1008: PetscCall(PetscOptionsInt("-snes_max_funcs", "Maximum function evaluations", "SNESSetTolerances", snes->max_funcs, &max_funcs, NULL));
1009: PetscCall(SNESSetTolerances(snes, abstol, rtol, stol, max_its, max_funcs));
1011: PetscCall(PetscOptionsReal("-snes_divergence_tolerance", "Stop if residual norm increases by this factor", "SNESSetDivergenceTolerance", snes->divtol, &snes->divtol, &flg));
1012: if (flg) PetscCall(SNESSetDivergenceTolerance(snes, snes->divtol));
1014: PetscCall(PetscOptionsInt("-snes_max_fail", "Maximum nonlinear step failures", "SNESSetMaxNonlinearStepFailures", snes->maxFailures, &snes->maxFailures, &flg));
1015: if (flg) PetscCall(SNESSetMaxNonlinearStepFailures(snes, snes->maxFailures));
1017: PetscCall(PetscOptionsInt("-snes_max_linear_solve_fail", "Maximum failures in linear solves allowed", "SNESSetMaxLinearSolveFailures", snes->maxLinearSolveFailures, &snes->maxLinearSolveFailures, &flg));
1018: if (flg) PetscCall(SNESSetMaxLinearSolveFailures(snes, snes->maxLinearSolveFailures));
1020: PetscCall(PetscOptionsBool("-snes_error_if_not_converged", "Generate error if solver does not converge", "SNESSetErrorIfNotConverged", snes->errorifnotconverged, &snes->errorifnotconverged, NULL));
1021: PetscCall(PetscOptionsBool("-snes_force_iteration", "Force SNESSolve() to take at least one iteration", "SNESSetForceIteration", snes->forceiteration, &snes->forceiteration, NULL));
1022: PetscCall(PetscOptionsBool("-snes_check_jacobian_domain_error", "Check Jacobian domain error after Jacobian evaluation", "SNESCheckJacobianDomainError", snes->checkjacdomainerror, &snes->checkjacdomainerror, NULL));
1024: PetscCall(PetscOptionsInt("-snes_lag_preconditioner", "How often to rebuild preconditioner", "SNESSetLagPreconditioner", snes->lagpreconditioner, &lag, &flg));
1025: if (flg) {
1026: PetscCheck(lag != -1, PetscObjectComm((PetscObject)snes), PETSC_ERR_USER, "Cannot set the lag to -1 from the command line since the preconditioner must be built as least once, perhaps you mean -2");
1027: PetscCall(SNESSetLagPreconditioner(snes, lag));
1028: }
1029: PetscCall(PetscOptionsBool("-snes_lag_preconditioner_persists", "Preconditioner lagging through multiple SNES solves", "SNESSetLagPreconditionerPersists", snes->lagjac_persist, &persist, &flg));
1030: if (flg) PetscCall(SNESSetLagPreconditionerPersists(snes, persist));
1031: PetscCall(PetscOptionsInt("-snes_lag_jacobian", "How often to rebuild Jacobian", "SNESSetLagJacobian", snes->lagjacobian, &lag, &flg));
1032: if (flg) {
1033: PetscCheck(lag != -1, PetscObjectComm((PetscObject)snes), PETSC_ERR_USER, "Cannot set the lag to -1 from the command line since the Jacobian must be built as least once, perhaps you mean -2");
1034: PetscCall(SNESSetLagJacobian(snes, lag));
1035: }
1036: PetscCall(PetscOptionsBool("-snes_lag_jacobian_persists", "Jacobian lagging through multiple SNES solves", "SNESSetLagJacobianPersists", snes->lagjac_persist, &persist, &flg));
1037: if (flg) PetscCall(SNESSetLagJacobianPersists(snes, persist));
1039: PetscCall(PetscOptionsInt("-snes_grid_sequence", "Use grid sequencing to generate initial guess", "SNESSetGridSequence", snes->gridsequence, &grids, &flg));
1040: if (flg) PetscCall(SNESSetGridSequence(snes, grids));
1042: PetscCall(PetscOptionsEList("-snes_convergence_test", "Convergence test", "SNESSetConvergenceTest", convtests, PETSC_STATIC_ARRAY_LENGTH(convtests), "default", &indx, &flg));
1043: if (flg) {
1044: switch (indx) {
1045: case 0:
1046: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedDefault, NULL, NULL));
1047: break;
1048: case 1:
1049: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedSkip, NULL, NULL));
1050: break;
1051: case 2:
1052: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedCorrectPressure, NULL, NULL));
1053: break;
1054: }
1055: }
1057: PetscCall(PetscOptionsEList("-snes_norm_schedule", "SNES Norm schedule", "SNESSetNormSchedule", SNESNormSchedules, 5, "function", &indx, &flg));
1058: if (flg) PetscCall(SNESSetNormSchedule(snes, (SNESNormSchedule)indx));
1060: PetscCall(PetscOptionsEList("-snes_function_type", "SNES Norm schedule", "SNESSetFunctionType", SNESFunctionTypes, 2, "unpreconditioned", &indx, &flg));
1061: if (flg) PetscCall(SNESSetFunctionType(snes, (SNESFunctionType)indx));
1063: kctx = (SNESKSPEW *)snes->kspconvctx;
1065: PetscCall(PetscOptionsBool("-snes_ksp_ew", "Use Eisentat-Walker linear system convergence test", "SNESKSPSetUseEW", snes->ksp_ewconv, &snes->ksp_ewconv, NULL));
1067: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1068: PetscCall(PetscSNPrintf(ewprefix, sizeof(ewprefix), "%s%s", optionsprefix ? optionsprefix : "", "snes_"));
1069: PetscCall(SNESEWSetFromOptions_Private(kctx, PETSC_TRUE, PetscObjectComm((PetscObject)snes), ewprefix));
1071: flg = PETSC_FALSE;
1072: PetscCall(PetscOptionsBool("-snes_monitor_cancel", "Remove all monitors", "SNESMonitorCancel", flg, &flg, &set));
1073: if (set && flg) PetscCall(SNESMonitorCancel(snes));
1075: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor", "Monitor norm of function", "SNESMonitorDefault", SNESMonitorDefault, SNESMonitorDefaultSetUp));
1076: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_short", "Monitor norm of function with fewer digits", "SNESMonitorDefaultShort", SNESMonitorDefaultShort, NULL));
1077: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_range", "Monitor range of elements of function", "SNESMonitorRange", SNESMonitorRange, NULL));
1079: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_ratio", "Monitor ratios of the norm of function for consecutive steps", "SNESMonitorRatio", SNESMonitorRatio, SNESMonitorRatioSetUp));
1080: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_field", "Monitor norm of function (split into fields)", "SNESMonitorDefaultField", SNESMonitorDefaultField, NULL));
1081: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution", "View solution at each iteration", "SNESMonitorSolution", SNESMonitorSolution, NULL));
1082: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution_update", "View correction at each iteration", "SNESMonitorSolutionUpdate", SNESMonitorSolutionUpdate, NULL));
1083: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_residual", "View residual at each iteration", "SNESMonitorResidual", SNESMonitorResidual, NULL));
1084: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_jacupdate_spectrum", "Print the change in the spectrum of the Jacobian", "SNESMonitorJacUpdateSpectrum", SNESMonitorJacUpdateSpectrum, NULL));
1085: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_fields", "Monitor norm of function per field", "SNESMonitorSet", SNESMonitorFields, NULL));
1086: PetscCall(PetscOptionsBool("-snes_monitor_pause_final", "Pauses all draw monitors at the final iterate", "SNESMonitorPauseFinal_Internal", PETSC_FALSE, &snes->pauseFinal, NULL));
1088: PetscCall(PetscOptionsString("-snes_monitor_python", "Use Python function", "SNESMonitorSet", NULL, monfilename, sizeof(monfilename), &flg));
1089: if (flg) PetscCall(PetscPythonMonitorSet((PetscObject)snes, monfilename));
1091: flg = PETSC_FALSE;
1092: PetscCall(PetscOptionsBool("-snes_monitor_lg_range", "Plot function range at each iteration", "SNESMonitorLGRange", flg, &flg, NULL));
1093: if (flg) {
1094: PetscViewer ctx;
1096: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, NULL, PETSC_DECIDE, PETSC_DECIDE, 400, 300, &ctx));
1097: PetscCall(SNESMonitorSet(snes, SNESMonitorLGRange, ctx, (PetscCtxDestroyFn *)PetscViewerDestroy));
1098: }
1100: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
1101: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_converged_reason", &snes->convergedreasonviewer, &snes->convergedreasonformat, NULL));
1102: flg = PETSC_FALSE;
1103: PetscCall(PetscOptionsBool("-snes_converged_reason_view_cancel", "Remove all converged reason viewers", "SNESConvergedReasonViewCancel", flg, &flg, &set));
1104: if (set && flg) PetscCall(SNESConvergedReasonViewCancel(snes));
1106: flg = PETSC_FALSE;
1107: PetscCall(PetscOptionsBool("-snes_fd", "Use finite differences (slow) to compute Jacobian", "SNESComputeJacobianDefault", flg, &flg, NULL));
1108: if (flg) {
1109: void *functx;
1110: DM dm;
1111: PetscCall(SNESGetDM(snes, &dm));
1112: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1113: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
1114: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefault, functx));
1115: PetscCall(PetscInfo(snes, "Setting default finite difference Jacobian matrix\n"));
1116: }
1118: flg = PETSC_FALSE;
1119: PetscCall(PetscOptionsBool("-snes_fd_function", "Use finite differences (slow) to compute function from user objective", "SNESObjectiveComputeFunctionDefaultFD", flg, &flg, NULL));
1120: if (flg) PetscCall(SNESSetFunction(snes, NULL, SNESObjectiveComputeFunctionDefaultFD, NULL));
1122: flg = PETSC_FALSE;
1123: PetscCall(PetscOptionsBool("-snes_fd_color", "Use finite differences with coloring to compute Jacobian", "SNESComputeJacobianDefaultColor", flg, &flg, NULL));
1124: if (flg) {
1125: DM dm;
1126: PetscCall(SNESGetDM(snes, &dm));
1127: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1128: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefaultColor, NULL));
1129: PetscCall(PetscInfo(snes, "Setting default finite difference coloring Jacobian matrix\n"));
1130: }
1132: flg = PETSC_FALSE;
1133: PetscCall(PetscOptionsBool("-snes_mf_operator", "Use a Matrix-Free Jacobian with user-provided matrix for computing the preconditioner", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf_operator, &flg));
1134: if (flg && snes->mf_operator) {
1135: snes->mf_operator = PETSC_TRUE;
1136: snes->mf = PETSC_TRUE;
1137: }
1138: flg = PETSC_FALSE;
1139: PetscCall(PetscOptionsBool("-snes_mf", "Use a Matrix-Free Jacobian with no matrix for computing the preconditioner", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf, &flg));
1140: if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1141: PetscCall(PetscOptionsInt("-snes_mf_version", "Matrix-Free routines version 1 or 2", "None", snes->mf_version, &snes->mf_version, NULL));
1143: PetscCall(PetscOptionsName("-snes_test_function", "Compare hand-coded and finite difference functions", "None", &snes->testFunc));
1144: PetscCall(PetscOptionsName("-snes_test_jacobian", "Compare hand-coded and finite difference Jacobians", "None", &snes->testJac));
1146: flg = PETSC_FALSE;
1147: PetscCall(SNESGetNPCSide(snes, &pcside));
1148: PetscCall(PetscOptionsEnum("-snes_npc_side", "SNES nonlinear preconditioner side", "SNESSetNPCSide", PCSides, (PetscEnum)pcside, (PetscEnum *)&pcside, &flg));
1149: if (flg) PetscCall(SNESSetNPCSide(snes, pcside));
1151: #if defined(PETSC_HAVE_SAWS)
1152: /*
1153: Publish convergence information using SAWs
1154: */
1155: flg = PETSC_FALSE;
1156: PetscCall(PetscOptionsBool("-snes_monitor_saws", "Publish SNES progress using SAWs", "SNESMonitorSet", flg, &flg, NULL));
1157: if (flg) {
1158: void *ctx;
1159: PetscCall(SNESMonitorSAWsCreate(snes, &ctx));
1160: PetscCall(SNESMonitorSet(snes, SNESMonitorSAWs, ctx, SNESMonitorSAWsDestroy));
1161: }
1162: #endif
1163: #if defined(PETSC_HAVE_SAWS)
1164: {
1165: PetscBool set;
1166: flg = PETSC_FALSE;
1167: PetscCall(PetscOptionsBool("-snes_saws_block", "Block for SAWs at end of SNESSolve", "PetscObjectSAWsBlock", ((PetscObject)snes)->amspublishblock, &flg, &set));
1168: if (set) PetscCall(PetscObjectSAWsSetBlock((PetscObject)snes, flg));
1169: }
1170: #endif
1172: for (i = 0; i < numberofsetfromoptions; i++) PetscCall((*othersetfromoptions[i])(snes));
1174: PetscTryTypeMethod(snes, setfromoptions, PetscOptionsObject);
1176: /* process any options handlers added with PetscObjectAddOptionsHandler() */
1177: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)snes, PetscOptionsObject));
1178: PetscOptionsEnd();
1180: if (snes->linesearch) {
1181: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
1182: PetscCall(SNESLineSearchSetFromOptions(snes->linesearch));
1183: }
1185: if (snes->usesksp) {
1186: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
1187: PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre));
1188: PetscCall(KSPSetFromOptions(snes->ksp));
1189: }
1191: /* if user has set the SNES NPC type via options database, create it. */
1192: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1193: PetscCall(PetscOptionsHasName(((PetscObject)snes)->options, optionsprefix, "-npc_snes_type", &pcset));
1194: if (pcset && (!snes->npc)) PetscCall(SNESGetNPC(snes, &snes->npc));
1195: if (snes->npc) PetscCall(SNESSetFromOptions(snes->npc));
1196: snes->setfromoptionscalled++;
1197: PetscFunctionReturn(PETSC_SUCCESS);
1198: }
1200: /*@
1201: SNESResetFromOptions - Sets various `SNES` and `KSP` parameters from user options ONLY if the `SNESSetFromOptions()` was previously called
1203: Collective
1205: Input Parameter:
1206: . snes - the `SNES` context
1208: Level: advanced
1210: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESSetOptionsPrefix()`
1211: @*/
1212: PetscErrorCode SNESResetFromOptions(SNES snes)
1213: {
1214: PetscFunctionBegin;
1215: if (snes->setfromoptionscalled) PetscCall(SNESSetFromOptions(snes));
1216: PetscFunctionReturn(PETSC_SUCCESS);
1217: }
1219: /*@C
1220: SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1221: the nonlinear solvers.
1223: Logically Collective; No Fortran Support
1225: Input Parameters:
1226: + snes - the `SNES` context
1227: . compute - function to compute the context
1228: - destroy - function to destroy the context, see `PetscCtxDestroyFn` for the calling sequence
1230: Calling sequence of `compute`:
1231: + snes - the `SNES` context
1232: - ctx - context to be computed
1234: Level: intermediate
1236: Note:
1237: This routine is useful if you are performing grid sequencing or using `SNESFAS` and need the appropriate context generated for each level.
1239: Use `SNESSetApplicationContext()` to see the context immediately
1241: .seealso: [](ch_snes), `SNESGetApplicationContext()`, `SNESSetApplicationContext()`, `PetscCtxDestroyFn`
1242: @*/
1243: PetscErrorCode SNESSetComputeApplicationContext(SNES snes, PetscErrorCode (*compute)(SNES snes, void **ctx), PetscCtxDestroyFn *destroy)
1244: {
1245: PetscFunctionBegin;
1247: snes->ops->usercompute = compute;
1248: snes->ops->ctxdestroy = destroy;
1249: PetscFunctionReturn(PETSC_SUCCESS);
1250: }
1252: /*@
1253: SNESSetApplicationContext - Sets the optional user-defined context for the nonlinear solvers.
1255: Logically Collective
1257: Input Parameters:
1258: + snes - the `SNES` context
1259: - ctx - the user context
1261: Level: intermediate
1263: Notes:
1264: Users can provide a context when constructing the `SNES` options and then access it inside their function, Jacobian computation, or other evaluation function
1265: with `SNESGetApplicationContext()`
1267: To provide a function that computes the context for you use `SNESSetComputeApplicationContext()`
1269: Fortran Note:
1270: This only works when `ctx` is a Fortran derived type (it cannot be a `PetscObject`), we recommend writing a Fortran interface definition for this
1271: function that tells the Fortran compiler the derived data type that is passed in as the `ctx` argument. See `SNESGetApplicationContext()` for
1272: an example.
1274: .seealso: [](ch_snes), `SNES`, `SNESSetComputeApplicationContext()`, `SNESGetApplicationContext()`
1275: @*/
1276: PetscErrorCode SNESSetApplicationContext(SNES snes, void *ctx)
1277: {
1278: KSP ksp;
1280: PetscFunctionBegin;
1282: PetscCall(SNESGetKSP(snes, &ksp));
1283: PetscCall(KSPSetApplicationContext(ksp, ctx));
1284: snes->ctx = ctx;
1285: PetscFunctionReturn(PETSC_SUCCESS);
1286: }
1288: /*@
1289: SNESGetApplicationContext - Gets the user-defined context for the
1290: nonlinear solvers set with `SNESGetApplicationContext()` or `SNESSetComputeApplicationContext()`
1292: Not Collective
1294: Input Parameter:
1295: . snes - `SNES` context
1297: Output Parameter:
1298: . ctx - user context
1300: Level: intermediate
1302: Fortran Notes:
1303: This only works when the context is a Fortran derived type (it cannot be a `PetscObject`) and you **must** write a Fortran interface definition for this
1304: function that tells the Fortran compiler the derived data type that is returned as the `ctx` argument. For example,
1305: .vb
1306: Interface SNESGetApplicationContext
1307: Subroutine SNESGetApplicationContext(snes,ctx,ierr)
1308: #include <petsc/finclude/petscsnes.h>
1309: use petscsnes
1310: SNES snes
1311: type(tUsertype), pointer :: ctx
1312: PetscErrorCode ierr
1313: End Subroutine
1314: End Interface SNESGetApplicationContext
1315: .ve
1317: The prototype for `ctx` must be
1318: .vb
1319: type(tUsertype), pointer :: ctx
1320: .ve
1322: .seealso: [](ch_snes), `SNESSetApplicationContext()`, `SNESSetComputeApplicationContext()`
1323: @*/
1324: PetscErrorCode SNESGetApplicationContext(SNES snes, PeCtx ctx)
1325: {
1326: PetscFunctionBegin;
1328: *(void **)ctx = snes->ctx;
1329: PetscFunctionReturn(PETSC_SUCCESS);
1330: }
1332: /*@
1333: SNESSetUseMatrixFree - indicates that `SNES` should use matrix-free finite difference matrix-vector products to apply the Jacobian.
1335: Logically Collective
1337: Input Parameters:
1338: + snes - `SNES` context
1339: . mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1340: - 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
1341: this option no matrix-element based preconditioners can be used in the linear solve since the matrix won't be explicitly available
1343: Options Database Keys:
1344: + -snes_mf_operator - use matrix-free only for the mat operator
1345: . -snes_mf - use matrix-free for both the mat and pmat operator
1346: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1347: - -snes_fd - compute the Jacobian via finite differences (slow)
1349: Level: intermediate
1351: Note:
1352: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
1353: and computing explicitly with
1354: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
1356: .seealso: [](ch_snes), `SNES`, `SNESGetUseMatrixFree()`, `MatCreateSNESMF()`, `SNESComputeJacobianDefaultColor()`, `MatFDColoring`
1357: @*/
1358: PetscErrorCode SNESSetUseMatrixFree(SNES snes, PetscBool mf_operator, PetscBool mf)
1359: {
1360: PetscFunctionBegin;
1364: snes->mf = mf_operator ? PETSC_TRUE : mf;
1365: snes->mf_operator = mf_operator;
1366: PetscFunctionReturn(PETSC_SUCCESS);
1367: }
1369: /*@
1370: SNESGetUseMatrixFree - indicates if the `SNES` uses matrix-free finite difference matrix vector products to apply the Jacobian.
1372: Not Collective, but the resulting flags will be the same on all MPI processes
1374: Input Parameter:
1375: . snes - `SNES` context
1377: Output Parameters:
1378: + mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1379: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored
1381: Level: intermediate
1383: .seealso: [](ch_snes), `SNES`, `SNESSetUseMatrixFree()`, `MatCreateSNESMF()`
1384: @*/
1385: PetscErrorCode SNESGetUseMatrixFree(SNES snes, PetscBool *mf_operator, PetscBool *mf)
1386: {
1387: PetscFunctionBegin;
1389: if (mf) *mf = snes->mf;
1390: if (mf_operator) *mf_operator = snes->mf_operator;
1391: PetscFunctionReturn(PETSC_SUCCESS);
1392: }
1394: /*@
1395: SNESGetIterationNumber - Gets the number of nonlinear iterations completed in the current or most recent `SNESSolve()`
1397: Not Collective
1399: Input Parameter:
1400: . snes - `SNES` context
1402: Output Parameter:
1403: . iter - iteration number
1405: Level: intermediate
1407: Notes:
1408: For example, during the computation of iteration 2 this would return 1.
1410: This is useful for using lagged Jacobians (where one does not recompute the
1411: Jacobian at each `SNES` iteration). For example, the code
1412: .vb
1413: ierr = SNESGetIterationNumber(snes,&it);
1414: if (!(it % 2)) {
1415: [compute Jacobian here]
1416: }
1417: .ve
1418: can be used in your function that computes the Jacobian to cause the Jacobian to be
1419: recomputed every second `SNES` iteration. See also `SNESSetLagJacobian()`
1421: After the `SNES` solve is complete this will return the number of nonlinear iterations used.
1423: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetLagJacobian()`, `SNESGetLinearSolveIterations()`, `SNESSetMonitor()`
1424: @*/
1425: PetscErrorCode SNESGetIterationNumber(SNES snes, PetscInt *iter)
1426: {
1427: PetscFunctionBegin;
1429: PetscAssertPointer(iter, 2);
1430: *iter = snes->iter;
1431: PetscFunctionReturn(PETSC_SUCCESS);
1432: }
1434: /*@
1435: SNESSetIterationNumber - Sets the current iteration number.
1437: Not Collective
1439: Input Parameters:
1440: + snes - `SNES` context
1441: - iter - iteration number
1443: Level: developer
1445: Note:
1446: This should only be called inside a `SNES` nonlinear solver.
1448: .seealso: [](ch_snes), `SNESGetLinearSolveIterations()`
1449: @*/
1450: PetscErrorCode SNESSetIterationNumber(SNES snes, PetscInt iter)
1451: {
1452: PetscFunctionBegin;
1454: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
1455: snes->iter = iter;
1456: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
1457: PetscFunctionReturn(PETSC_SUCCESS);
1458: }
1460: /*@
1461: SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1462: attempted by the nonlinear solver in the current or most recent `SNESSolve()` .
1464: Not Collective
1466: Input Parameter:
1467: . snes - `SNES` context
1469: Output Parameter:
1470: . nfails - number of unsuccessful steps attempted
1472: Level: intermediate
1474: Note:
1475: This counter is reset to zero for each successive call to `SNESSolve()`.
1477: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1478: `SNESSetMaxNonlinearStepFailures()`, `SNESGetMaxNonlinearStepFailures()`
1479: @*/
1480: PetscErrorCode SNESGetNonlinearStepFailures(SNES snes, PetscInt *nfails)
1481: {
1482: PetscFunctionBegin;
1484: PetscAssertPointer(nfails, 2);
1485: *nfails = snes->numFailures;
1486: PetscFunctionReturn(PETSC_SUCCESS);
1487: }
1489: /*@
1490: SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1491: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1493: Not Collective
1495: Input Parameters:
1496: + snes - `SNES` context
1497: - maxFails - maximum of unsuccessful steps allowed, use `PETSC_UNLIMITED` to have no limit on the number of failures
1499: Options Database Key:
1500: . -snes_max_fail <n> - maximum number of unsuccessful steps allowed
1502: Level: intermediate
1504: Developer Note:
1505: The options database key is wrong for this function name
1507: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1508: `SNESGetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1509: @*/
1510: PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1511: {
1512: PetscFunctionBegin;
1515: if (maxFails == PETSC_UNLIMITED) {
1516: snes->maxFailures = PETSC_INT_MAX;
1517: } else {
1518: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1519: snes->maxFailures = maxFails;
1520: }
1521: PetscFunctionReturn(PETSC_SUCCESS);
1522: }
1524: /*@
1525: SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1526: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1528: Not Collective
1530: Input Parameter:
1531: . snes - `SNES` context
1533: Output Parameter:
1534: . maxFails - maximum of unsuccessful steps
1536: Level: intermediate
1538: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1539: `SNESSetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1540: @*/
1541: PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1542: {
1543: PetscFunctionBegin;
1545: PetscAssertPointer(maxFails, 2);
1546: *maxFails = snes->maxFailures;
1547: PetscFunctionReturn(PETSC_SUCCESS);
1548: }
1550: /*@
1551: SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1552: done by the `SNES` object in the current or most recent `SNESSolve()`
1554: Not Collective
1556: Input Parameter:
1557: . snes - `SNES` context
1559: Output Parameter:
1560: . nfuncs - number of evaluations
1562: Level: intermediate
1564: Note:
1565: Reset every time `SNESSolve()` is called unless `SNESSetCountersReset()` is used.
1567: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`, `SNESSetCountersReset()`
1568: @*/
1569: PetscErrorCode SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1570: {
1571: PetscFunctionBegin;
1573: PetscAssertPointer(nfuncs, 2);
1574: *nfuncs = snes->nfuncs;
1575: PetscFunctionReturn(PETSC_SUCCESS);
1576: }
1578: /*@
1579: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1580: linear solvers in the current or most recent `SNESSolve()`
1582: Not Collective
1584: Input Parameter:
1585: . snes - `SNES` context
1587: Output Parameter:
1588: . nfails - number of failed solves
1590: Options Database Key:
1591: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1593: Level: intermediate
1595: Note:
1596: This counter is reset to zero for each successive call to `SNESSolve()`.
1598: .seealso: [](ch_snes), `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1599: @*/
1600: PetscErrorCode SNESGetLinearSolveFailures(SNES snes, PetscInt *nfails)
1601: {
1602: PetscFunctionBegin;
1604: PetscAssertPointer(nfails, 2);
1605: *nfails = snes->numLinearSolveFailures;
1606: PetscFunctionReturn(PETSC_SUCCESS);
1607: }
1609: /*@
1610: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1611: allowed before `SNES` returns with a diverged reason of `SNES_DIVERGED_LINEAR_SOLVE`
1613: Logically Collective
1615: Input Parameters:
1616: + snes - `SNES` context
1617: - maxFails - maximum allowed linear solve failures, use `PETSC_UNLIMITED` to have no limit on the number of failures
1619: Options Database Key:
1620: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1622: Level: intermediate
1624: Note:
1625: By default this is 0; that is `SNES` returns on the first failed linear solve
1627: Developer Note:
1628: The options database key is wrong for this function name
1630: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`
1631: @*/
1632: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1633: {
1634: PetscFunctionBegin;
1638: if (maxFails == PETSC_UNLIMITED) {
1639: snes->maxLinearSolveFailures = PETSC_INT_MAX;
1640: } else {
1641: PetscCheck(maxFails >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Cannot have a negative maximum number of failures");
1642: snes->maxLinearSolveFailures = maxFails;
1643: }
1644: PetscFunctionReturn(PETSC_SUCCESS);
1645: }
1647: /*@
1648: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1649: are allowed before `SNES` returns as unsuccessful
1651: Not Collective
1653: Input Parameter:
1654: . snes - `SNES` context
1656: Output Parameter:
1657: . maxFails - maximum of unsuccessful solves allowed
1659: Level: intermediate
1661: Note:
1662: By default this is 1; that is `SNES` returns on the first failed linear solve
1664: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`,
1665: @*/
1666: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1667: {
1668: PetscFunctionBegin;
1670: PetscAssertPointer(maxFails, 2);
1671: *maxFails = snes->maxLinearSolveFailures;
1672: PetscFunctionReturn(PETSC_SUCCESS);
1673: }
1675: /*@
1676: SNESGetLinearSolveIterations - Gets the total number of linear iterations
1677: used by the nonlinear solver in the most recent `SNESSolve()`
1679: Not Collective
1681: Input Parameter:
1682: . snes - `SNES` context
1684: Output Parameter:
1685: . lits - number of linear iterations
1687: Level: intermediate
1689: Notes:
1690: This counter is reset to zero for each successive call to `SNESSolve()` unless `SNESSetCountersReset()` is used.
1692: 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
1693: then call `KSPGetIterationNumber()` after the failed solve.
1695: .seealso: [](ch_snes), `SNES`, `SNESGetIterationNumber()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESSetCountersReset()`
1696: @*/
1697: PetscErrorCode SNESGetLinearSolveIterations(SNES snes, PetscInt *lits)
1698: {
1699: PetscFunctionBegin;
1701: PetscAssertPointer(lits, 2);
1702: *lits = snes->linear_its;
1703: PetscFunctionReturn(PETSC_SUCCESS);
1704: }
1706: /*@
1707: SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1708: are reset every time `SNESSolve()` is called.
1710: Logically Collective
1712: Input Parameters:
1713: + snes - `SNES` context
1714: - reset - whether to reset the counters or not, defaults to `PETSC_TRUE`
1716: Level: developer
1718: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1719: @*/
1720: PetscErrorCode SNESSetCountersReset(SNES snes, PetscBool reset)
1721: {
1722: PetscFunctionBegin;
1725: snes->counters_reset = reset;
1726: PetscFunctionReturn(PETSC_SUCCESS);
1727: }
1729: /*@
1730: SNESResetCounters - Reset counters for linear iterations and function evaluations.
1732: Logically Collective
1734: Input Parameters:
1735: . snes - `SNES` context
1737: Level: developer
1739: Note:
1740: It honors the flag set with `SNESSetCountersReset()`
1742: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1743: @*/
1744: PetscErrorCode SNESResetCounters(SNES snes)
1745: {
1746: PetscFunctionBegin;
1748: if (snes->counters_reset) {
1749: snes->nfuncs = 0;
1750: snes->linear_its = 0;
1751: snes->numFailures = 0;
1752: }
1753: PetscFunctionReturn(PETSC_SUCCESS);
1754: }
1756: /*@
1757: SNESSetKSP - Sets a `KSP` context for the `SNES` object to use
1759: Not Collective, but the `SNES` and `KSP` objects must live on the same `MPI_Comm`
1761: Input Parameters:
1762: + snes - the `SNES` context
1763: - ksp - the `KSP` context
1765: Level: developer
1767: Notes:
1768: The `SNES` object already has its `KSP` object, you can obtain with `SNESGetKSP()`
1769: so this routine is rarely needed.
1771: The `KSP` object that is already in the `SNES` object has its reference count
1772: decreased by one when this is called.
1774: .seealso: [](ch_snes), `SNES`, `KSP`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`
1775: @*/
1776: PetscErrorCode SNESSetKSP(SNES snes, KSP ksp)
1777: {
1778: PetscFunctionBegin;
1781: PetscCheckSameComm(snes, 1, ksp, 2);
1782: PetscCall(PetscObjectReference((PetscObject)ksp));
1783: if (snes->ksp) PetscCall(PetscObjectDereference((PetscObject)snes->ksp));
1784: snes->ksp = ksp;
1785: PetscFunctionReturn(PETSC_SUCCESS);
1786: }
1788: /*@
1789: SNESParametersInitialize - Sets all the parameters in `snes` to their default value (when `SNESCreate()` was called) if they
1790: currently contain default values
1792: Collective
1794: Input Parameter:
1795: . snes - the `SNES` object
1797: Level: developer
1799: Developer Note:
1800: This is called by all the `SNESCreate_XXX()` routines.
1802: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`,
1803: `PetscObjectParameterSetDefault()`
1804: @*/
1805: PetscErrorCode SNESParametersInitialize(SNES snes)
1806: {
1807: PetscObjectParameterSetDefault(snes, max_its, 50);
1808: PetscObjectParameterSetDefault(snes, max_funcs, 10000);
1809: PetscObjectParameterSetDefault(snes, rtol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1810: PetscObjectParameterSetDefault(snes, abstol, PetscDefined(USE_REAL_SINGLE) ? 1.e-25 : 1.e-50);
1811: PetscObjectParameterSetDefault(snes, stol, PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8);
1812: PetscObjectParameterSetDefault(snes, divtol, 1.e4);
1813: return PETSC_SUCCESS;
1814: }
1816: /*@
1817: SNESCreate - Creates a nonlinear solver context used to manage a set of nonlinear solves
1819: Collective
1821: Input Parameter:
1822: . comm - MPI communicator
1824: Output Parameter:
1825: . outsnes - the new `SNES` context
1827: Options Database Keys:
1828: + -snes_mf - Activates default matrix-free Jacobian-vector products, and no matrix to construct a preconditioner
1829: . -snes_mf_operator - Activates default matrix-free Jacobian-vector products, and a user-provided matrix as set by `SNESSetJacobian()`
1830: . -snes_fd_coloring - uses a relative fast computation of the Jacobian using finite differences and a graph coloring
1831: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
1833: Level: beginner
1835: Developer Notes:
1836: `SNES` always creates a `KSP` object even though many `SNES` methods do not use it. This is
1837: unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1838: particular method does use `KSP` and regulates if the information about the `KSP` is printed
1839: in `SNESView()`.
1841: `TSSetFromOptions()` does call `SNESSetFromOptions()` which can lead to users being confused
1842: by help messages about meaningless `SNES` options.
1844: `SNES` always creates the `snes->kspconvctx` even though it is used by only one type. This should be fixed.
1846: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
1847: @*/
1848: PetscErrorCode SNESCreate(MPI_Comm comm, SNES *outsnes)
1849: {
1850: SNES snes;
1851: SNESKSPEW *kctx;
1853: PetscFunctionBegin;
1854: PetscAssertPointer(outsnes, 2);
1855: PetscCall(SNESInitializePackage());
1857: PetscCall(PetscHeaderCreate(snes, SNES_CLASSID, "SNES", "Nonlinear solver", "SNES", comm, SNESDestroy, SNESView));
1858: snes->ops->converged = SNESConvergedDefault;
1859: snes->usesksp = PETSC_TRUE;
1860: snes->norm = 0.0;
1861: snes->xnorm = 0.0;
1862: snes->ynorm = 0.0;
1863: snes->normschedule = SNES_NORM_ALWAYS;
1864: snes->functype = SNES_FUNCTION_DEFAULT;
1865: snes->ttol = 0.0;
1867: snes->rnorm0 = 0;
1868: snes->nfuncs = 0;
1869: snes->numFailures = 0;
1870: snes->maxFailures = 1;
1871: snes->linear_its = 0;
1872: snes->lagjacobian = 1;
1873: snes->jac_iter = 0;
1874: snes->lagjac_persist = PETSC_FALSE;
1875: snes->lagpreconditioner = 1;
1876: snes->pre_iter = 0;
1877: snes->lagpre_persist = PETSC_FALSE;
1878: snes->numbermonitors = 0;
1879: snes->numberreasonviews = 0;
1880: snes->data = NULL;
1881: snes->setupcalled = PETSC_FALSE;
1882: snes->ksp_ewconv = PETSC_FALSE;
1883: snes->nwork = 0;
1884: snes->work = NULL;
1885: snes->nvwork = 0;
1886: snes->vwork = NULL;
1887: snes->conv_hist_len = 0;
1888: snes->conv_hist_max = 0;
1889: snes->conv_hist = NULL;
1890: snes->conv_hist_its = NULL;
1891: snes->conv_hist_reset = PETSC_TRUE;
1892: snes->counters_reset = PETSC_TRUE;
1893: snes->vec_func_init_set = PETSC_FALSE;
1894: snes->reason = SNES_CONVERGED_ITERATING;
1895: snes->npcside = PC_RIGHT;
1896: snes->setfromoptionscalled = 0;
1898: snes->mf = PETSC_FALSE;
1899: snes->mf_operator = PETSC_FALSE;
1900: snes->mf_version = 1;
1902: snes->numLinearSolveFailures = 0;
1903: snes->maxLinearSolveFailures = 1;
1905: snes->vizerotolerance = 1.e-8;
1906: snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;
1908: /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1909: snes->alwayscomputesfinalresidual = PETSC_FALSE;
1911: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1912: PetscCall(PetscNew(&kctx));
1914: snes->kspconvctx = kctx;
1915: kctx->version = 2;
1916: kctx->rtol_0 = 0.3; /* Eisenstat and Walker suggest rtol_0=.5, but
1917: this was too large for some test cases */
1918: kctx->rtol_last = 0.0;
1919: kctx->rtol_max = 0.9;
1920: kctx->gamma = 1.0;
1921: kctx->alpha = 0.5 * (1.0 + PetscSqrtReal(5.0));
1922: kctx->alpha2 = kctx->alpha;
1923: kctx->threshold = 0.1;
1924: kctx->lresid_last = 0.0;
1925: kctx->norm_last = 0.0;
1927: kctx->rk_last = 0.0;
1928: kctx->rk_last_2 = 0.0;
1929: kctx->rtol_last_2 = 0.0;
1930: kctx->v4_p1 = 0.1;
1931: kctx->v4_p2 = 0.4;
1932: kctx->v4_p3 = 0.7;
1933: kctx->v4_m1 = 0.8;
1934: kctx->v4_m2 = 0.5;
1935: kctx->v4_m3 = 0.1;
1936: kctx->v4_m4 = 0.5;
1938: PetscCall(SNESParametersInitialize(snes));
1939: *outsnes = snes;
1940: PetscFunctionReturn(PETSC_SUCCESS);
1941: }
1943: /*@C
1944: SNESSetFunction - Sets the function evaluation routine and function
1945: vector for use by the `SNES` routines in solving systems of nonlinear
1946: equations.
1948: Logically Collective
1950: Input Parameters:
1951: + snes - the `SNES` context
1952: . r - vector to store function values, may be `NULL`
1953: . f - function evaluation routine; for calling sequence see `SNESFunctionFn`
1954: - ctx - [optional] user-defined context for private data for the
1955: function evaluation routine (may be `NULL`)
1957: Level: beginner
1959: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetPicard()`, `SNESFunctionFn`
1960: @*/
1961: PetscErrorCode SNESSetFunction(SNES snes, Vec r, SNESFunctionFn *f, void *ctx)
1962: {
1963: DM dm;
1965: PetscFunctionBegin;
1967: if (r) {
1969: PetscCheckSameComm(snes, 1, r, 2);
1970: PetscCall(PetscObjectReference((PetscObject)r));
1971: PetscCall(VecDestroy(&snes->vec_func));
1972: snes->vec_func = r;
1973: }
1974: PetscCall(SNESGetDM(snes, &dm));
1975: PetscCall(DMSNESSetFunction(dm, f, ctx));
1976: if (f == SNESPicardComputeFunction) PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
1977: PetscFunctionReturn(PETSC_SUCCESS);
1978: }
1980: /*@C
1981: SNESSetInitialFunction - Set an already computed function evaluation at the initial guess to be reused by `SNESSolve()`.
1983: Logically Collective
1985: Input Parameters:
1986: + snes - the `SNES` context
1987: - f - vector to store function value
1989: Level: developer
1991: Notes:
1992: This should not be modified during the solution procedure.
1994: This is used extensively in the `SNESFAS` hierarchy and in nonlinear preconditioning.
1996: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetInitialFunctionNorm()`
1997: @*/
1998: PetscErrorCode SNESSetInitialFunction(SNES snes, Vec f)
1999: {
2000: Vec vec_func;
2002: PetscFunctionBegin;
2005: PetscCheckSameComm(snes, 1, f, 2);
2006: if (snes->npcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
2007: snes->vec_func_init_set = PETSC_FALSE;
2008: PetscFunctionReturn(PETSC_SUCCESS);
2009: }
2010: PetscCall(SNESGetFunction(snes, &vec_func, NULL, NULL));
2011: PetscCall(VecCopy(f, vec_func));
2013: snes->vec_func_init_set = PETSC_TRUE;
2014: PetscFunctionReturn(PETSC_SUCCESS);
2015: }
2017: /*@
2018: SNESSetNormSchedule - Sets the `SNESNormSchedule` used in convergence and monitoring
2019: of the `SNES` method, when norms are computed in the solving process
2021: Logically Collective
2023: Input Parameters:
2024: + snes - the `SNES` context
2025: - normschedule - the frequency of norm computation
2027: Options Database Key:
2028: . -snes_norm_schedule <none, always, initialonly, finalonly, initialfinalonly> - set the schedule
2030: Level: advanced
2032: Notes:
2033: Only certain `SNES` methods support certain `SNESNormSchedules`. Most require evaluation
2034: of the nonlinear function and the taking of its norm at every iteration to
2035: even ensure convergence at all. However, methods such as custom Gauss-Seidel methods
2036: `SNESNGS` and the like do not require the norm of the function to be computed, and therefore
2037: may either be monitored for convergence or not. As these are often used as nonlinear
2038: preconditioners, monitoring the norm of their error is not a useful enterprise within
2039: their solution.
2041: .seealso: [](ch_snes), `SNESNormSchedule`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`
2042: @*/
2043: PetscErrorCode SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
2044: {
2045: PetscFunctionBegin;
2047: snes->normschedule = normschedule;
2048: PetscFunctionReturn(PETSC_SUCCESS);
2049: }
2051: /*@
2052: SNESGetNormSchedule - Gets the `SNESNormSchedule` used in convergence and monitoring
2053: of the `SNES` method.
2055: Logically Collective
2057: Input Parameters:
2058: + snes - the `SNES` context
2059: - normschedule - the type of the norm used
2061: Level: advanced
2063: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2064: @*/
2065: PetscErrorCode SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
2066: {
2067: PetscFunctionBegin;
2069: *normschedule = snes->normschedule;
2070: PetscFunctionReturn(PETSC_SUCCESS);
2071: }
2073: /*@
2074: SNESSetFunctionNorm - Sets the last computed residual norm.
2076: Logically Collective
2078: Input Parameters:
2079: + snes - the `SNES` context
2080: - norm - the value of the norm
2082: Level: developer
2084: .seealso: [](ch_snes), `SNES`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2085: @*/
2086: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
2087: {
2088: PetscFunctionBegin;
2090: snes->norm = norm;
2091: PetscFunctionReturn(PETSC_SUCCESS);
2092: }
2094: /*@
2095: SNESGetFunctionNorm - Gets the last computed norm of the residual
2097: Not Collective
2099: Input Parameter:
2100: . snes - the `SNES` context
2102: Output Parameter:
2103: . norm - the last computed residual norm
2105: Level: developer
2107: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2108: @*/
2109: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
2110: {
2111: PetscFunctionBegin;
2113: PetscAssertPointer(norm, 2);
2114: *norm = snes->norm;
2115: PetscFunctionReturn(PETSC_SUCCESS);
2116: }
2118: /*@
2119: SNESGetUpdateNorm - Gets the last computed norm of the solution update
2121: Not Collective
2123: Input Parameter:
2124: . snes - the `SNES` context
2126: Output Parameter:
2127: . ynorm - the last computed update norm
2129: Level: developer
2131: Note:
2132: The new solution is the current solution plus the update, so this norm is an indication of the size of the update
2134: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`
2135: @*/
2136: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2137: {
2138: PetscFunctionBegin;
2140: PetscAssertPointer(ynorm, 2);
2141: *ynorm = snes->ynorm;
2142: PetscFunctionReturn(PETSC_SUCCESS);
2143: }
2145: /*@
2146: SNESGetSolutionNorm - Gets the last computed norm of the solution
2148: Not Collective
2150: Input Parameter:
2151: . snes - the `SNES` context
2153: Output Parameter:
2154: . xnorm - the last computed solution norm
2156: Level: developer
2158: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`, `SNESGetUpdateNorm()`
2159: @*/
2160: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2161: {
2162: PetscFunctionBegin;
2164: PetscAssertPointer(xnorm, 2);
2165: *xnorm = snes->xnorm;
2166: PetscFunctionReturn(PETSC_SUCCESS);
2167: }
2169: /*@
2170: SNESSetFunctionType - Sets the `SNESFunctionType`
2171: of the `SNES` method.
2173: Logically Collective
2175: Input Parameters:
2176: + snes - the `SNES` context
2177: - type - the function type
2179: Level: developer
2181: Values of the function type\:
2182: + `SNES_FUNCTION_DEFAULT` - the default for the given `SNESType`
2183: . `SNES_FUNCTION_UNPRECONDITIONED` - an unpreconditioned function evaluation (this is the function provided with `SNESSetFunction()`
2184: - `SNES_FUNCTION_PRECONDITIONED` - a transformation of the function provided with `SNESSetFunction()`
2186: Note:
2187: Different `SNESType`s use this value in different ways
2189: .seealso: [](ch_snes), `SNES`, `SNESFunctionType`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2190: @*/
2191: PetscErrorCode SNESSetFunctionType(SNES snes, SNESFunctionType type)
2192: {
2193: PetscFunctionBegin;
2195: snes->functype = type;
2196: PetscFunctionReturn(PETSC_SUCCESS);
2197: }
2199: /*@
2200: SNESGetFunctionType - Gets the `SNESFunctionType` used in convergence and monitoring set with `SNESSetFunctionType()`
2201: of the SNES method.
2203: Logically Collective
2205: Input Parameters:
2206: + snes - the `SNES` context
2207: - type - the type of the function evaluation, see `SNESSetFunctionType()`
2209: Level: advanced
2211: .seealso: [](ch_snes), `SNESSetFunctionType()`, `SNESFunctionType`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2212: @*/
2213: PetscErrorCode SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2214: {
2215: PetscFunctionBegin;
2217: *type = snes->functype;
2218: PetscFunctionReturn(PETSC_SUCCESS);
2219: }
2221: /*@C
2222: SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2223: use with composed nonlinear solvers.
2225: Input Parameters:
2226: + snes - the `SNES` context, usually of the `SNESType` `SNESNGS`
2227: . f - function evaluation routine to apply Gauss-Seidel, see `SNESNGSFn` for calling sequence
2228: - ctx - [optional] user-defined context for private data for the smoother evaluation routine (may be `NULL`)
2230: Level: intermediate
2232: Note:
2233: The `SNESNGS` routines are used by the composed nonlinear solver to generate
2234: a problem appropriate update to the solution, particularly `SNESFAS`.
2236: .seealso: [](ch_snes), `SNESNGS`, `SNESGetNGS()`, `SNESNCG`, `SNESGetFunction()`, `SNESComputeNGS()`, `SNESNGSFn`
2237: @*/
2238: PetscErrorCode SNESSetNGS(SNES snes, SNESNGSFn *f, void *ctx)
2239: {
2240: DM dm;
2242: PetscFunctionBegin;
2244: PetscCall(SNESGetDM(snes, &dm));
2245: PetscCall(DMSNESSetNGS(dm, f, ctx));
2246: PetscFunctionReturn(PETSC_SUCCESS);
2247: }
2249: /*
2250: This is used for -snes_mf_operator; it uses a duplicate of snes->jacobian_pre because snes->jacobian_pre cannot be
2251: changed during the KSPSolve()
2252: */
2253: PetscErrorCode SNESPicardComputeMFFunction(SNES snes, Vec x, Vec f, void *ctx)
2254: {
2255: DM dm;
2256: DMSNES sdm;
2258: PetscFunctionBegin;
2259: PetscCall(SNESGetDM(snes, &dm));
2260: PetscCall(DMGetDMSNES(dm, &sdm));
2261: /* A(x)*x - b(x) */
2262: if (sdm->ops->computepfunction) {
2263: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2264: PetscCall(VecScale(f, -1.0));
2265: /* Cannot share nonzero pattern because of the possible use of SNESComputeJacobianDefault() */
2266: if (!snes->picard) PetscCall(MatDuplicate(snes->jacobian_pre, MAT_DO_NOT_COPY_VALUES, &snes->picard));
2267: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2268: PetscCall(MatMultAdd(snes->picard, x, f, f));
2269: } else {
2270: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2271: PetscCall(MatMult(snes->picard, x, f));
2272: }
2273: PetscFunctionReturn(PETSC_SUCCESS);
2274: }
2276: PetscErrorCode SNESPicardComputeFunction(SNES snes, Vec x, Vec f, void *ctx)
2277: {
2278: DM dm;
2279: DMSNES sdm;
2281: PetscFunctionBegin;
2282: PetscCall(SNESGetDM(snes, &dm));
2283: PetscCall(DMGetDMSNES(dm, &sdm));
2284: /* A(x)*x - b(x) */
2285: if (sdm->ops->computepfunction) {
2286: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2287: PetscCall(VecScale(f, -1.0));
2288: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2289: PetscCall(MatMultAdd(snes->jacobian_pre, x, f, f));
2290: } else {
2291: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2292: PetscCall(MatMult(snes->jacobian_pre, x, f));
2293: }
2294: PetscFunctionReturn(PETSC_SUCCESS);
2295: }
2297: PetscErrorCode SNESPicardComputeJacobian(SNES snes, Vec x1, Mat J, Mat B, void *ctx)
2298: {
2299: PetscFunctionBegin;
2300: /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2301: /* must assembly if matrix-free to get the last SNES solution */
2302: PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
2303: PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
2304: PetscFunctionReturn(PETSC_SUCCESS);
2305: }
2307: /*@C
2308: SNESSetPicard - Use `SNES` to solve the system $A(x) x = bp(x) + b $ via a Picard type iteration (Picard linearization)
2310: Logically Collective
2312: Input Parameters:
2313: + snes - the `SNES` context
2314: . r - vector to store function values, may be `NULL`
2315: . bp - function evaluation routine, may be `NULL`, for the calling sequence see `SNESFunctionFn`
2316: . Amat - matrix with which $A(x) x - bp(x) - b$ is to be computed
2317: . Pmat - matrix from which preconditioner is computed (usually the same as `Amat`)
2318: . J - function to compute matrix values, for the calling sequence see `SNESJacobianFn`
2319: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
2321: Level: intermediate
2323: Notes:
2324: It is often better to provide the nonlinear function $F()$ and some approximation to its Jacobian directly and use
2325: 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.
2327: One can call `SNESSetPicard()` or `SNESSetFunction()` (and possibly `SNESSetJacobian()`) but cannot call both
2329: Solves the equation $A(x) x = bp(x) - b$ via the defect correction algorithm $A(x^{n}) (x^{n+1} - x^{n}) = bp(x^{n}) + b - A(x^{n})x^{n}$.
2330: When an exact solver is used this corresponds to the "classic" Picard $A(x^{n}) x^{n+1} = bp(x^{n}) + b$ iteration.
2332: Run with `-snes_mf_operator` to solve the system with Newton's method using $A(x^{n})$ to construct the preconditioner.
2334: We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2335: the direct Picard iteration $A(x^n) x^{n+1} = bp(x^n) + b$
2337: 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
2338: 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
2339: different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument \:-).
2341: 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
2342: $A(x^{n})$ is used to build the preconditioner
2344: When used with `-snes_fd` this will compute the true Jacobian (very slowly one column at a time) and thus represent Newton's method.
2346: 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
2347: 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
2348: 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`.
2349: See the comment in src/snes/tutorials/ex15.c.
2351: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESGetPicard()`, `SNESLineSearchPreCheckPicard()`,
2352: `SNESFunctionFn`, `SNESJacobianFn`
2353: @*/
2354: PetscErrorCode SNESSetPicard(SNES snes, Vec r, SNESFunctionFn *bp, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
2355: {
2356: DM dm;
2358: PetscFunctionBegin;
2360: PetscCall(SNESGetDM(snes, &dm));
2361: PetscCall(DMSNESSetPicard(dm, bp, J, ctx));
2362: PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2363: PetscCall(SNESSetFunction(snes, r, SNESPicardComputeFunction, ctx));
2364: PetscCall(SNESSetJacobian(snes, Amat, Pmat, SNESPicardComputeJacobian, ctx));
2365: PetscFunctionReturn(PETSC_SUCCESS);
2366: }
2368: /*@C
2369: SNESGetPicard - Returns the context for the Picard iteration
2371: Not Collective, but `Vec` is parallel if `SNES` is parallel. Collective if `Vec` is requested, but has not been created yet.
2373: Input Parameter:
2374: . snes - the `SNES` context
2376: Output Parameters:
2377: + r - the function (or `NULL`)
2378: . f - the function (or `NULL`); for calling sequence see `SNESFunctionFn`
2379: . Amat - the matrix used to defined the operation A(x) x - b(x) (or `NULL`)
2380: . Pmat - the matrix from which the preconditioner will be constructed (or `NULL`)
2381: . J - the function for matrix evaluation (or `NULL`); for calling sequence see `SNESJacobianFn`
2382: - ctx - the function context (or `NULL`)
2384: Level: advanced
2386: .seealso: [](ch_snes), `SNESSetFunction()`, `SNESSetPicard()`, `SNESGetFunction()`, `SNESGetJacobian()`, `SNESGetDM()`, `SNESFunctionFn`, `SNESJacobianFn`
2387: @*/
2388: PetscErrorCode SNESGetPicard(SNES snes, Vec *r, SNESFunctionFn **f, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
2389: {
2390: DM dm;
2392: PetscFunctionBegin;
2394: PetscCall(SNESGetFunction(snes, r, NULL, NULL));
2395: PetscCall(SNESGetJacobian(snes, Amat, Pmat, NULL, NULL));
2396: PetscCall(SNESGetDM(snes, &dm));
2397: PetscCall(DMSNESGetPicard(dm, f, J, ctx));
2398: PetscFunctionReturn(PETSC_SUCCESS);
2399: }
2401: /*@C
2402: SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the nonlinear problem
2404: Logically Collective
2406: Input Parameters:
2407: + snes - the `SNES` context
2408: . func - function evaluation routine, see `SNESInitialGuessFn` for the calling sequence
2409: - ctx - [optional] user-defined context for private data for the
2410: function evaluation routine (may be `NULL`)
2412: Level: intermediate
2414: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESInitialGuessFn`
2415: @*/
2416: PetscErrorCode SNESSetComputeInitialGuess(SNES snes, SNESInitialGuessFn *func, void *ctx)
2417: {
2418: PetscFunctionBegin;
2420: if (func) snes->ops->computeinitialguess = func;
2421: if (ctx) snes->initialguessP = ctx;
2422: PetscFunctionReturn(PETSC_SUCCESS);
2423: }
2425: /*@C
2426: SNESGetRhs - Gets the vector for solving F(x) = `rhs`. If `rhs` is not set
2427: it assumes a zero right-hand side.
2429: Logically Collective
2431: Input Parameter:
2432: . snes - the `SNES` context
2434: Output Parameter:
2435: . rhs - the right-hand side vector or `NULL` if there is no right-hand side vector
2437: Level: intermediate
2439: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetFunction()`
2440: @*/
2441: PetscErrorCode SNESGetRhs(SNES snes, Vec *rhs)
2442: {
2443: PetscFunctionBegin;
2445: PetscAssertPointer(rhs, 2);
2446: *rhs = snes->vec_rhs;
2447: PetscFunctionReturn(PETSC_SUCCESS);
2448: }
2450: /*@
2451: SNESComputeFunction - Calls the function that has been set with `SNESSetFunction()`.
2453: Collective
2455: Input Parameters:
2456: + snes - the `SNES` context
2457: - x - input vector
2459: Output Parameter:
2460: . y - function vector, as set by `SNESSetFunction()`
2462: Level: developer
2464: Notes:
2465: `SNESComputeFunction()` is typically used within nonlinear solvers
2466: implementations, so users would not generally call this routine themselves.
2468: When solving for $F(x) = b$, this routine computes $y = F(x) - b$.
2470: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeMFFunction()`
2471: @*/
2472: PetscErrorCode SNESComputeFunction(SNES snes, Vec x, Vec y)
2473: {
2474: DM dm;
2475: DMSNES sdm;
2477: PetscFunctionBegin;
2481: PetscCheckSameComm(snes, 1, x, 2);
2482: PetscCheckSameComm(snes, 1, y, 3);
2483: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2485: PetscCall(SNESGetDM(snes, &dm));
2486: PetscCall(DMGetDMSNES(dm, &sdm));
2487: 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().");
2488: if (sdm->ops->computefunction) {
2489: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2490: PetscCall(VecLockReadPush(x));
2491: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2492: snes->domainerror = PETSC_FALSE;
2493: {
2494: void *ctx;
2495: SNESFunctionFn *computefunction;
2496: PetscCall(DMSNESGetFunction(dm, &computefunction, &ctx));
2497: PetscCallBack("SNES callback function", (*computefunction)(snes, x, y, ctx));
2498: }
2499: PetscCall(VecLockReadPop(x));
2500: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2501: } else /* if (snes->vec_rhs) */ {
2502: PetscCall(MatMult(snes->jacobian, x, y));
2503: }
2504: if (snes->vec_rhs) PetscCall(VecAXPY(y, -1.0, snes->vec_rhs));
2505: snes->nfuncs++;
2506: /*
2507: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2508: propagate the value to all processes
2509: */
2510: PetscCall(VecFlag(y, snes->domainerror));
2511: PetscFunctionReturn(PETSC_SUCCESS);
2512: }
2514: /*@
2515: SNESComputeMFFunction - Calls the function that has been set with `DMSNESSetMFFunction()`.
2517: Collective
2519: Input Parameters:
2520: + snes - the `SNES` context
2521: - x - input vector
2523: Output Parameter:
2524: . y - output vector
2526: Level: developer
2528: Notes:
2529: `SNESComputeMFFunction()` is used within the matrix-vector products called by the matrix created with `MatCreateSNESMF()`
2530: so users would not generally call this routine themselves.
2532: Since this function is intended for use with finite differencing it does not subtract the right-hand side vector provided with `SNESSolve()`
2533: while `SNESComputeFunction()` does. As such, this routine cannot be used with `MatMFFDSetBase()` with a provided F function value even if it applies the
2534: 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.
2536: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `MatCreateSNESMF()`, `DMSNESSetMFFunction()`
2537: @*/
2538: PetscErrorCode SNESComputeMFFunction(SNES snes, Vec x, Vec y)
2539: {
2540: DM dm;
2541: DMSNES sdm;
2543: PetscFunctionBegin;
2547: PetscCheckSameComm(snes, 1, x, 2);
2548: PetscCheckSameComm(snes, 1, y, 3);
2549: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2551: PetscCall(SNESGetDM(snes, &dm));
2552: PetscCall(DMGetDMSNES(dm, &sdm));
2553: PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2554: PetscCall(VecLockReadPush(x));
2555: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2556: snes->domainerror = PETSC_FALSE;
2557: PetscCallBack("SNES callback function", (*sdm->ops->computemffunction)(snes, x, y, sdm->mffunctionctx));
2558: PetscCall(VecLockReadPop(x));
2559: PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2560: snes->nfuncs++;
2561: /*
2562: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2563: propagate the value to all processes
2564: */
2565: PetscCall(VecFlag(y, snes->domainerror));
2566: PetscFunctionReturn(PETSC_SUCCESS);
2567: }
2569: /*@
2570: SNESComputeNGS - Calls the Gauss-Seidel function that has been set with `SNESSetNGS()`.
2572: Collective
2574: Input Parameters:
2575: + snes - the `SNES` context
2576: . x - input vector
2577: - b - rhs vector
2579: Output Parameter:
2580: . x - new solution vector
2582: Level: developer
2584: Note:
2585: `SNESComputeNGS()` is typically used within composed nonlinear solver
2586: implementations, so most users would not generally call this routine
2587: themselves.
2589: .seealso: [](ch_snes), `SNESNGSFn`, `SNESSetNGS()`, `SNESComputeFunction()`, `SNESNGS`
2590: @*/
2591: PetscErrorCode SNESComputeNGS(SNES snes, Vec b, Vec x)
2592: {
2593: DM dm;
2594: DMSNES sdm;
2596: PetscFunctionBegin;
2600: PetscCheckSameComm(snes, 1, x, 3);
2601: if (b) PetscCheckSameComm(snes, 1, b, 2);
2602: if (b) PetscCall(VecValidValues_Internal(b, 2, PETSC_TRUE));
2603: PetscCall(PetscLogEventBegin(SNES_NGSEval, snes, x, b, 0));
2604: PetscCall(SNESGetDM(snes, &dm));
2605: PetscCall(DMGetDMSNES(dm, &sdm));
2606: PetscCheck(sdm->ops->computegs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2607: if (b) PetscCall(VecLockReadPush(b));
2608: PetscCallBack("SNES callback NGS", (*sdm->ops->computegs)(snes, x, b, sdm->gsctx));
2609: if (b) PetscCall(VecLockReadPop(b));
2610: PetscCall(PetscLogEventEnd(SNES_NGSEval, snes, x, b, 0));
2611: PetscFunctionReturn(PETSC_SUCCESS);
2612: }
2614: static PetscErrorCode SNESComputeFunction_FD(SNES snes, Vec Xin, Vec G)
2615: {
2616: Vec X;
2617: PetscScalar *g;
2618: PetscReal f, f2;
2619: PetscInt low, high, N, i;
2620: PetscBool flg;
2621: PetscReal h = .5 * PETSC_SQRT_MACHINE_EPSILON;
2623: PetscFunctionBegin;
2624: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_fd_delta", &h, &flg));
2625: PetscCall(VecDuplicate(Xin, &X));
2626: PetscCall(VecCopy(Xin, X));
2627: PetscCall(VecGetSize(X, &N));
2628: PetscCall(VecGetOwnershipRange(X, &low, &high));
2629: PetscCall(VecSetOption(X, VEC_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE));
2630: PetscCall(VecGetArray(G, &g));
2631: for (i = 0; i < N; i++) {
2632: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2633: PetscCall(VecAssemblyBegin(X));
2634: PetscCall(VecAssemblyEnd(X));
2635: PetscCall(SNESComputeObjective(snes, X, &f));
2636: PetscCall(VecSetValue(X, i, 2.0 * h, ADD_VALUES));
2637: PetscCall(VecAssemblyBegin(X));
2638: PetscCall(VecAssemblyEnd(X));
2639: PetscCall(SNESComputeObjective(snes, X, &f2));
2640: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2641: PetscCall(VecAssemblyBegin(X));
2642: PetscCall(VecAssemblyEnd(X));
2643: if (i >= low && i < high) g[i - low] = (f2 - f) / (2.0 * h);
2644: }
2645: PetscCall(VecRestoreArray(G, &g));
2646: PetscCall(VecDestroy(&X));
2647: PetscFunctionReturn(PETSC_SUCCESS);
2648: }
2650: /*@
2651: SNESTestFunction - Computes the difference between the computed and finite-difference functions
2653: Collective
2655: Input Parameter:
2656: . snes - the `SNES` context
2658: Options Database Keys:
2659: + -snes_test_function - compare the user provided function with one compute via finite differences to check for errors.
2660: - -snes_test_function_view - display the user provided function, the finite difference function and the difference
2662: Level: developer
2664: .seealso: [](ch_snes), `SNESTestJacobian()`, `SNESSetFunction()`, `SNESComputeFunction()`
2665: @*/
2666: PetscErrorCode SNESTestFunction(SNES snes)
2667: {
2668: Vec x, g1, g2, g3;
2669: PetscBool complete_print = PETSC_FALSE;
2670: PetscReal hcnorm, fdnorm, hcmax, fdmax, diffmax, diffnorm;
2671: PetscScalar dot;
2672: MPI_Comm comm;
2673: PetscViewer viewer, mviewer;
2674: PetscViewerFormat format;
2675: PetscInt tabs;
2676: static PetscBool directionsprinted = PETSC_FALSE;
2677: SNESObjectiveFn *objective;
2679: PetscFunctionBegin;
2680: PetscCall(SNESGetObjective(snes, &objective, NULL));
2681: if (!objective) PetscFunctionReturn(PETSC_SUCCESS);
2683: PetscObjectOptionsBegin((PetscObject)snes);
2684: PetscCall(PetscOptionsViewer("-snes_test_function_view", "View difference between hand-coded and finite difference function element entries", "None", &mviewer, &format, &complete_print));
2685: PetscOptionsEnd();
2687: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2688: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2689: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2690: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2691: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Function -------------\n"));
2692: if (!complete_print && !directionsprinted) {
2693: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_function_view and optionally -snes_test_function <threshold> to show difference\n"));
2694: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference function entries greater than <threshold>.\n"));
2695: }
2696: if (!directionsprinted) {
2697: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Function, if (for double precision runs) ||F - Ffd||/||F|| is\n"));
2698: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Function is probably correct.\n"));
2699: directionsprinted = PETSC_TRUE;
2700: }
2701: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2703: PetscCall(SNESGetSolution(snes, &x));
2704: PetscCall(VecDuplicate(x, &g1));
2705: PetscCall(VecDuplicate(x, &g2));
2706: PetscCall(VecDuplicate(x, &g3));
2707: PetscCall(SNESComputeFunction(snes, x, g1));
2708: PetscCall(SNESComputeFunction_FD(snes, x, g2));
2710: PetscCall(VecNorm(g2, NORM_2, &fdnorm));
2711: PetscCall(VecNorm(g1, NORM_2, &hcnorm));
2712: PetscCall(VecNorm(g2, NORM_INFINITY, &fdmax));
2713: PetscCall(VecNorm(g1, NORM_INFINITY, &hcmax));
2714: PetscCall(VecDot(g1, g2, &dot));
2715: PetscCall(VecCopy(g1, g3));
2716: PetscCall(VecAXPY(g3, -1.0, g2));
2717: PetscCall(VecNorm(g3, NORM_2, &diffnorm));
2718: PetscCall(VecNorm(g3, NORM_INFINITY, &diffmax));
2719: PetscCall(PetscViewerASCIIPrintf(viewer, " ||Ffd|| %g, ||F|| = %g, angle cosine = (Ffd'F)/||Ffd||||F|| = %g\n", (double)fdnorm, (double)hcnorm, (double)(PetscRealPart(dot) / (fdnorm * hcnorm))));
2720: PetscCall(PetscViewerASCIIPrintf(viewer, " 2-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffnorm / PetscMax(hcnorm, fdnorm)), (double)diffnorm));
2721: PetscCall(PetscViewerASCIIPrintf(viewer, " max-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffmax / PetscMax(hcmax, fdmax)), (double)diffmax));
2723: if (complete_print) {
2724: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded function ----------\n"));
2725: PetscCall(VecView(g1, mviewer));
2726: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference function ----------\n"));
2727: PetscCall(VecView(g2, mviewer));
2728: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference function ----------\n"));
2729: PetscCall(VecView(g3, mviewer));
2730: }
2731: PetscCall(VecDestroy(&g1));
2732: PetscCall(VecDestroy(&g2));
2733: PetscCall(VecDestroy(&g3));
2735: if (complete_print) {
2736: PetscCall(PetscViewerPopFormat(mviewer));
2737: PetscCall(PetscViewerDestroy(&mviewer));
2738: }
2739: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2740: PetscFunctionReturn(PETSC_SUCCESS);
2741: }
2743: /*@
2744: SNESTestJacobian - Computes the difference between the computed and finite-difference Jacobians
2746: Collective
2748: Input Parameter:
2749: . snes - the `SNES` context
2751: Output Parameters:
2752: + Jnorm - the Frobenius norm of the computed Jacobian, or `NULL`
2753: - diffNorm - the Frobenius norm of the difference of the computed and finite-difference Jacobians, or `NULL`
2755: Options Database Keys:
2756: + -snes_test_jacobian <optional threshold> - compare the user provided Jacobian with one compute via finite differences to check for errors. If a threshold is given, display only those entries whose difference is greater than the threshold.
2757: - -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference
2759: Level: developer
2761: Note:
2762: Directions and norms are printed to stdout if `diffNorm` is `NULL`.
2764: .seealso: [](ch_snes), `SNESTestFunction()`, `SNESSetJacobian()`, `SNESComputeJacobian()`
2765: @*/
2766: PetscErrorCode SNESTestJacobian(SNES snes, PetscReal *Jnorm, PetscReal *diffNorm)
2767: {
2768: Mat A, B, C, D, jacobian;
2769: Vec x = snes->vec_sol, f;
2770: PetscReal nrm, gnorm;
2771: PetscReal threshold = 1.e-5;
2772: MatType mattype;
2773: PetscInt m, n, M, N;
2774: void *functx;
2775: PetscBool complete_print = PETSC_FALSE, threshold_print = PETSC_FALSE, flg, istranspose;
2776: PetscBool silent = diffNorm != PETSC_NULLPTR ? PETSC_TRUE : PETSC_FALSE;
2777: PetscViewer viewer, mviewer;
2778: MPI_Comm comm;
2779: PetscInt tabs;
2780: static PetscBool directionsprinted = PETSC_FALSE;
2781: PetscViewerFormat format;
2783: PetscFunctionBegin;
2784: PetscObjectOptionsBegin((PetscObject)snes);
2785: PetscCall(PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold, NULL));
2786: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display", "-snes_test_jacobian_view", "3.13", NULL));
2787: PetscCall(PetscOptionsViewer("-snes_test_jacobian_view", "View difference between hand-coded and finite difference Jacobians element entries", "None", &mviewer, &format, &complete_print));
2788: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display_threshold", "-snes_test_jacobian", "3.13", "-snes_test_jacobian accepts an optional threshold (since v3.10)"));
2789: 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));
2790: PetscOptionsEnd();
2792: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2793: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2794: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2795: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2796: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian -------------\n"));
2797: if (!complete_print && !silent && !directionsprinted) {
2798: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n"));
2799: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference Jacobian entries greater than <threshold>.\n"));
2800: }
2801: if (!directionsprinted && !silent) {
2802: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n"));
2803: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Jacobian is probably correct.\n"));
2804: directionsprinted = PETSC_TRUE;
2805: }
2806: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2808: PetscCall(PetscObjectTypeCompare((PetscObject)snes->jacobian, MATMFFD, &flg));
2809: if (!flg) jacobian = snes->jacobian;
2810: else jacobian = snes->jacobian_pre;
2812: if (!x) PetscCall(MatCreateVecs(jacobian, &x, NULL));
2813: else PetscCall(PetscObjectReference((PetscObject)x));
2814: PetscCall(VecDuplicate(x, &f));
2816: /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2817: PetscCall(SNESComputeFunction(snes, x, f));
2818: PetscCall(VecDestroy(&f));
2819: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESKSPTRANSPOSEONLY, &istranspose));
2820: while (jacobian) {
2821: Mat JT = NULL, Jsave = NULL;
2823: if (istranspose) {
2824: PetscCall(MatCreateTranspose(jacobian, &JT));
2825: Jsave = jacobian;
2826: jacobian = JT;
2827: }
2828: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)jacobian, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
2829: if (flg) {
2830: A = jacobian;
2831: PetscCall(PetscObjectReference((PetscObject)A));
2832: } else {
2833: PetscCall(MatComputeOperator(jacobian, MATAIJ, &A));
2834: }
2836: PetscCall(MatGetType(A, &mattype));
2837: PetscCall(MatGetSize(A, &M, &N));
2838: PetscCall(MatGetLocalSize(A, &m, &n));
2839: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &B));
2840: PetscCall(MatSetType(B, mattype));
2841: PetscCall(MatSetSizes(B, m, n, M, N));
2842: PetscCall(MatSetBlockSizesFromMats(B, A, A));
2843: PetscCall(MatSetUp(B));
2844: PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2846: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
2847: PetscCall(SNESComputeJacobianDefault(snes, x, B, B, functx));
2849: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &D));
2850: PetscCall(MatAYPX(D, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2851: PetscCall(MatNorm(D, NORM_FROBENIUS, &nrm));
2852: PetscCall(MatNorm(A, NORM_FROBENIUS, &gnorm));
2853: PetscCall(MatDestroy(&D));
2854: if (!gnorm) gnorm = 1; /* just in case */
2855: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n", (double)(nrm / gnorm), (double)nrm));
2856: if (complete_print) {
2857: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded Jacobian ----------\n"));
2858: PetscCall(MatView(A, mviewer));
2859: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference Jacobian ----------\n"));
2860: PetscCall(MatView(B, mviewer));
2861: }
2863: if (threshold_print || complete_print) {
2864: PetscInt Istart, Iend, *ccols, bncols, cncols, j, row;
2865: PetscScalar *cvals;
2866: const PetscInt *bcols;
2867: const PetscScalar *bvals;
2869: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2870: PetscCall(MatSetType(C, mattype));
2871: PetscCall(MatSetSizes(C, m, n, M, N));
2872: PetscCall(MatSetBlockSizesFromMats(C, A, A));
2873: PetscCall(MatSetUp(C));
2874: PetscCall(MatSetOption(C, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2876: PetscCall(MatAYPX(B, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2877: PetscCall(MatGetOwnershipRange(B, &Istart, &Iend));
2879: for (row = Istart; row < Iend; row++) {
2880: PetscCall(MatGetRow(B, row, &bncols, &bcols, &bvals));
2881: PetscCall(PetscMalloc2(bncols, &ccols, bncols, &cvals));
2882: for (j = 0, cncols = 0; j < bncols; j++) {
2883: if (PetscAbsScalar(bvals[j]) > threshold) {
2884: ccols[cncols] = bcols[j];
2885: cvals[cncols] = bvals[j];
2886: cncols += 1;
2887: }
2888: }
2889: if (cncols) PetscCall(MatSetValues(C, 1, &row, cncols, ccols, cvals, INSERT_VALUES));
2890: PetscCall(MatRestoreRow(B, row, &bncols, &bcols, &bvals));
2891: PetscCall(PetscFree2(ccols, cvals));
2892: }
2893: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2894: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2895: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n", (double)threshold));
2896: PetscCall(MatView(C, complete_print ? mviewer : viewer));
2897: PetscCall(MatDestroy(&C));
2898: }
2899: PetscCall(MatDestroy(&A));
2900: PetscCall(MatDestroy(&B));
2901: PetscCall(MatDestroy(&JT));
2902: if (Jsave) jacobian = Jsave;
2903: if (jacobian != snes->jacobian_pre) {
2904: jacobian = snes->jacobian_pre;
2905: if (!silent) PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian for preconditioner -------------\n"));
2906: } else jacobian = NULL;
2907: }
2908: PetscCall(VecDestroy(&x));
2909: if (complete_print) PetscCall(PetscViewerPopFormat(mviewer));
2910: if (mviewer) PetscCall(PetscViewerDestroy(&mviewer));
2911: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2913: if (Jnorm) *Jnorm = gnorm;
2914: if (diffNorm) *diffNorm = nrm;
2915: PetscFunctionReturn(PETSC_SUCCESS);
2916: }
2918: /*@
2919: SNESComputeJacobian - Computes the Jacobian matrix that has been set with `SNESSetJacobian()`.
2921: Collective
2923: Input Parameters:
2924: + snes - the `SNES` context
2925: - X - input vector
2927: Output Parameters:
2928: + A - Jacobian matrix
2929: - B - optional matrix for building the preconditioner, usually the same as `A`
2931: Options Database Keys:
2932: + -snes_lag_preconditioner <lag> - how often to rebuild preconditioner
2933: . -snes_lag_jacobian <lag> - how often to rebuild Jacobian
2934: . -snes_test_jacobian <optional threshold> - compare the user provided Jacobian with one compute via finite differences to check for errors. If a threshold is given, display only those entries whose difference is greater than the threshold.
2935: . -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference between them to help users detect the location of errors in the user provided Jacobian
2936: . -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2937: . -snes_compare_explicit_draw - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2938: . -snes_compare_explicit_contour - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2939: . -snes_compare_operator - Make the comparison options above use the operator instead of the matrix used to construct the preconditioner
2940: . -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2941: . -snes_compare_coloring_display - Compute the finite difference Jacobian using coloring and display verbose differences
2942: . -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2943: . -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2944: . -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2945: . -snes_compare_coloring_draw - Compute the finite difference Jacobian using coloring and draw differences
2946: - -snes_compare_coloring_draw_contour - Compute the finite difference Jacobian using coloring and show contours of matrices and differences
2948: Level: developer
2950: Note:
2951: Most users should not need to explicitly call this routine, as it
2952: is used internally within the nonlinear solvers.
2954: Developer Note:
2955: 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
2956: with the `SNESType` of test that has been removed.
2958: .seealso: [](ch_snes), `SNESSetJacobian()`, `KSPSetOperators()`, `MatStructure`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
2959: @*/
2960: PetscErrorCode SNESComputeJacobian(SNES snes, Vec X, Mat A, Mat B)
2961: {
2962: PetscBool flag;
2963: DM dm;
2964: DMSNES sdm;
2965: KSP ksp;
2967: PetscFunctionBegin;
2970: PetscCheckSameComm(snes, 1, X, 2);
2971: PetscCall(VecValidValues_Internal(X, 2, PETSC_TRUE));
2972: PetscCall(SNESGetDM(snes, &dm));
2973: PetscCall(DMGetDMSNES(dm, &sdm));
2975: /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix-free */
2976: if (snes->lagjacobian == -2) {
2977: snes->lagjacobian = -1;
2979: PetscCall(PetscInfo(snes, "Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n"));
2980: } else if (snes->lagjacobian == -1) {
2981: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is -1\n"));
2982: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2983: if (flag) {
2984: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2985: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2986: }
2987: PetscFunctionReturn(PETSC_SUCCESS);
2988: } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2989: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagjacobian, snes->iter));
2990: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2991: if (flag) {
2992: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2993: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2994: }
2995: PetscFunctionReturn(PETSC_SUCCESS);
2996: }
2997: if (snes->npc && snes->npcside == PC_LEFT) {
2998: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2999: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
3000: PetscFunctionReturn(PETSC_SUCCESS);
3001: }
3003: PetscCall(PetscLogEventBegin(SNES_JacobianEval, snes, X, A, B));
3004: PetscCall(VecLockReadPush(X));
3005: {
3006: void *ctx;
3007: SNESJacobianFn *J;
3008: PetscCall(DMSNESGetJacobian(dm, &J, &ctx));
3009: PetscCallBack("SNES callback Jacobian", (*J)(snes, X, A, B, ctx));
3010: }
3011: PetscCall(VecLockReadPop(X));
3012: PetscCall(PetscLogEventEnd(SNES_JacobianEval, snes, X, A, B));
3014: /* attach latest linearization point to the matrix used to construct the preconditioner */
3015: PetscCall(PetscObjectCompose((PetscObject)B, "__SNES_latest_X", (PetscObject)X));
3017: /* the next line ensures that snes->ksp exists */
3018: PetscCall(SNESGetKSP(snes, &ksp));
3019: if (snes->lagpreconditioner == -2) {
3020: PetscCall(PetscInfo(snes, "Rebuilding preconditioner exactly once since lag is -2\n"));
3021: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
3022: snes->lagpreconditioner = -1;
3023: } else if (snes->lagpreconditioner == -1) {
3024: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is -1\n"));
3025: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
3026: } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
3027: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagpreconditioner, snes->iter));
3028: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
3029: } else {
3030: PetscCall(PetscInfo(snes, "Rebuilding preconditioner\n"));
3031: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
3032: }
3034: /* monkey business to allow testing Jacobians in multilevel solvers.
3035: This is needed because the SNESTestXXX interface does not accept vectors and matrices */
3036: {
3037: Vec xsave = snes->vec_sol;
3038: Mat jacobiansave = snes->jacobian;
3039: Mat jacobian_presave = snes->jacobian_pre;
3041: snes->vec_sol = X;
3042: snes->jacobian = A;
3043: snes->jacobian_pre = B;
3044: if (snes->testFunc) PetscCall(SNESTestFunction(snes));
3045: if (snes->testJac) PetscCall(SNESTestJacobian(snes, NULL, NULL));
3047: snes->vec_sol = xsave;
3048: snes->jacobian = jacobiansave;
3049: snes->jacobian_pre = jacobian_presave;
3050: }
3052: {
3053: PetscBool flag = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_operator = PETSC_FALSE;
3054: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit", NULL, NULL, &flag));
3055: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw", NULL, NULL, &flag_draw));
3056: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw_contour", NULL, NULL, &flag_contour));
3057: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_operator", NULL, NULL, &flag_operator));
3058: if (flag || flag_draw || flag_contour) {
3059: Mat Bexp_mine = NULL, Bexp, FDexp;
3060: PetscViewer vdraw, vstdout;
3061: PetscBool flg;
3062: if (flag_operator) {
3063: PetscCall(MatComputeOperator(A, MATAIJ, &Bexp_mine));
3064: Bexp = Bexp_mine;
3065: } else {
3066: /* See if the matrix used to construct the preconditioner can be viewed and added directly */
3067: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)B, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPIBAIJ, ""));
3068: if (flg) Bexp = B;
3069: else {
3070: /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
3071: PetscCall(MatComputeOperator(B, MATAIJ, &Bexp_mine));
3072: Bexp = Bexp_mine;
3073: }
3074: }
3075: PetscCall(MatConvert(Bexp, MATSAME, MAT_INITIAL_MATRIX, &FDexp));
3076: PetscCall(SNESComputeJacobianDefault(snes, X, FDexp, FDexp, NULL));
3077: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3078: if (flag_draw || flag_contour) {
3079: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Explicit Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3080: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3081: } else vdraw = NULL;
3082: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit %s\n", flag_operator ? "Jacobian" : "preconditioning Jacobian"));
3083: if (flag) PetscCall(MatView(Bexp, vstdout));
3084: if (vdraw) PetscCall(MatView(Bexp, vdraw));
3085: PetscCall(PetscViewerASCIIPrintf(vstdout, "Finite difference Jacobian\n"));
3086: if (flag) PetscCall(MatView(FDexp, vstdout));
3087: if (vdraw) PetscCall(MatView(FDexp, vdraw));
3088: PetscCall(MatAYPX(FDexp, -1.0, Bexp, SAME_NONZERO_PATTERN));
3089: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian\n"));
3090: if (flag) PetscCall(MatView(FDexp, vstdout));
3091: if (vdraw) { /* Always use contour for the difference */
3092: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3093: PetscCall(MatView(FDexp, vdraw));
3094: PetscCall(PetscViewerPopFormat(vdraw));
3095: }
3096: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3097: PetscCall(PetscViewerDestroy(&vdraw));
3098: PetscCall(MatDestroy(&Bexp_mine));
3099: PetscCall(MatDestroy(&FDexp));
3100: }
3101: }
3102: {
3103: PetscBool flag = PETSC_FALSE, flag_display = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_threshold = PETSC_FALSE;
3104: PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON, threshold_rtol = 10 * PETSC_SQRT_MACHINE_EPSILON;
3105: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring", NULL, NULL, &flag));
3106: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_display", NULL, NULL, &flag_display));
3107: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw", NULL, NULL, &flag_draw));
3108: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw_contour", NULL, NULL, &flag_contour));
3109: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold", NULL, NULL, &flag_threshold));
3110: if (flag_threshold) {
3111: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_rtol", &threshold_rtol, NULL));
3112: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_atol", &threshold_atol, NULL));
3113: }
3114: if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
3115: Mat Bfd;
3116: PetscViewer vdraw, vstdout;
3117: MatColoring coloring;
3118: ISColoring iscoloring;
3119: MatFDColoring matfdcoloring;
3120: SNESFunctionFn *func;
3121: void *funcctx;
3122: PetscReal norm1, norm2, normmax;
3124: PetscCall(MatDuplicate(B, MAT_DO_NOT_COPY_VALUES, &Bfd));
3125: PetscCall(MatColoringCreate(Bfd, &coloring));
3126: PetscCall(MatColoringSetType(coloring, MATCOLORINGSL));
3127: PetscCall(MatColoringSetFromOptions(coloring));
3128: PetscCall(MatColoringApply(coloring, &iscoloring));
3129: PetscCall(MatColoringDestroy(&coloring));
3130: PetscCall(MatFDColoringCreate(Bfd, iscoloring, &matfdcoloring));
3131: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3132: PetscCall(MatFDColoringSetUp(Bfd, iscoloring, matfdcoloring));
3133: PetscCall(ISColoringDestroy(&iscoloring));
3135: /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
3136: PetscCall(SNESGetFunction(snes, NULL, &func, &funcctx));
3137: PetscCall(MatFDColoringSetFunction(matfdcoloring, (MatFDColoringFn *)func, funcctx));
3138: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring, ((PetscObject)snes)->prefix));
3139: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring, "coloring_"));
3140: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3141: PetscCall(MatFDColoringApply(Bfd, matfdcoloring, X, snes));
3142: PetscCall(MatFDColoringDestroy(&matfdcoloring));
3144: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3145: if (flag_draw || flag_contour) {
3146: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Colored Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3147: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3148: } else vdraw = NULL;
3149: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit preconditioning Jacobian\n"));
3150: if (flag_display) PetscCall(MatView(B, vstdout));
3151: if (vdraw) PetscCall(MatView(B, vdraw));
3152: PetscCall(PetscViewerASCIIPrintf(vstdout, "Colored Finite difference Jacobian\n"));
3153: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3154: if (vdraw) PetscCall(MatView(Bfd, vdraw));
3155: PetscCall(MatAYPX(Bfd, -1.0, B, SAME_NONZERO_PATTERN));
3156: PetscCall(MatNorm(Bfd, NORM_1, &norm1));
3157: PetscCall(MatNorm(Bfd, NORM_FROBENIUS, &norm2));
3158: PetscCall(MatNorm(Bfd, NORM_MAX, &normmax));
3159: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n", (double)norm1, (double)norm2, (double)normmax));
3160: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3161: if (vdraw) { /* Always use contour for the difference */
3162: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3163: PetscCall(MatView(Bfd, vdraw));
3164: PetscCall(PetscViewerPopFormat(vdraw));
3165: }
3166: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3168: if (flag_threshold) {
3169: PetscInt bs, rstart, rend, i;
3170: PetscCall(MatGetBlockSize(B, &bs));
3171: PetscCall(MatGetOwnershipRange(B, &rstart, &rend));
3172: for (i = rstart; i < rend; i++) {
3173: const PetscScalar *ba, *ca;
3174: const PetscInt *bj, *cj;
3175: PetscInt bn, cn, j, maxentrycol = -1, maxdiffcol = -1, maxrdiffcol = -1;
3176: PetscReal maxentry = 0, maxdiff = 0, maxrdiff = 0;
3177: PetscCall(MatGetRow(B, i, &bn, &bj, &ba));
3178: PetscCall(MatGetRow(Bfd, i, &cn, &cj, &ca));
3179: PetscCheck(bn == cn, ((PetscObject)A)->comm, PETSC_ERR_PLIB, "Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
3180: for (j = 0; j < bn; j++) {
3181: PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3182: if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
3183: maxentrycol = bj[j];
3184: maxentry = PetscRealPart(ba[j]);
3185: }
3186: if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
3187: maxdiffcol = bj[j];
3188: maxdiff = PetscRealPart(ca[j]);
3189: }
3190: if (rdiff > maxrdiff) {
3191: maxrdiffcol = bj[j];
3192: maxrdiff = rdiff;
3193: }
3194: }
3195: if (maxrdiff > 1) {
3196: 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));
3197: for (j = 0; j < bn; j++) {
3198: PetscReal rdiff;
3199: rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3200: if (rdiff > 1) PetscCall(PetscViewerASCIIPrintf(vstdout, " (%" PetscInt_FMT ",%g:%g)", bj[j], (double)PetscRealPart(ba[j]), (double)PetscRealPart(ca[j])));
3201: }
3202: PetscCall(PetscViewerASCIIPrintf(vstdout, "\n"));
3203: }
3204: PetscCall(MatRestoreRow(B, i, &bn, &bj, &ba));
3205: PetscCall(MatRestoreRow(Bfd, i, &cn, &cj, &ca));
3206: }
3207: }
3208: PetscCall(PetscViewerDestroy(&vdraw));
3209: PetscCall(MatDestroy(&Bfd));
3210: }
3211: }
3212: PetscFunctionReturn(PETSC_SUCCESS);
3213: }
3215: /*@C
3216: SNESSetJacobian - Sets the function to compute Jacobian as well as the
3217: location to store the matrix.
3219: Logically Collective
3221: Input Parameters:
3222: + snes - the `SNES` context
3223: . Amat - the matrix that defines the (approximate) Jacobian
3224: . Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
3225: . J - Jacobian evaluation routine (if `NULL` then `SNES` retains any previously set value), see `SNESJacobianFn` for details
3226: - ctx - [optional] user-defined context for private data for the
3227: Jacobian evaluation routine (may be `NULL`) (if `NULL` then `SNES` retains any previously set value)
3229: Level: beginner
3231: Notes:
3232: If the `Amat` matrix and `Pmat` matrix are different you must call `MatAssemblyBegin()`/`MatAssemblyEnd()` on
3233: each matrix.
3235: If you know the operator `Amat` has a null space you can use `MatSetNullSpace()` and `MatSetTransposeNullSpace()` to supply the null
3236: space to `Amat` and the `KSP` solvers will automatically use that null space as needed during the solution process.
3238: If using `SNESComputeJacobianDefaultColor()` to assemble a Jacobian, the `ctx` argument
3239: must be a `MatFDColoring`.
3241: Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian. One common
3242: example is to use the "Picard linearization" which only differentiates through the highest order parts of each term using `SNESSetPicard()`
3244: .seealso: [](ch_snes), `SNES`, `KSPSetOperators()`, `SNESSetFunction()`, `MatMFFDComputeJacobian()`, `SNESComputeJacobianDefaultColor()`, `MatStructure`,
3245: `SNESSetPicard()`, `SNESJacobianFn`, `SNESFunctionFn`
3246: @*/
3247: PetscErrorCode SNESSetJacobian(SNES snes, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
3248: {
3249: DM dm;
3251: PetscFunctionBegin;
3255: if (Amat) PetscCheckSameComm(snes, 1, Amat, 2);
3256: if (Pmat) PetscCheckSameComm(snes, 1, Pmat, 3);
3257: PetscCall(SNESGetDM(snes, &dm));
3258: PetscCall(DMSNESSetJacobian(dm, J, ctx));
3259: if (Amat) {
3260: PetscCall(PetscObjectReference((PetscObject)Amat));
3261: PetscCall(MatDestroy(&snes->jacobian));
3263: snes->jacobian = Amat;
3264: }
3265: if (Pmat) {
3266: PetscCall(PetscObjectReference((PetscObject)Pmat));
3267: PetscCall(MatDestroy(&snes->jacobian_pre));
3269: snes->jacobian_pre = Pmat;
3270: }
3271: PetscFunctionReturn(PETSC_SUCCESS);
3272: }
3274: /*@C
3275: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
3276: provided context for evaluating the Jacobian.
3278: Not Collective, but `Mat` object will be parallel if `SNES` is
3280: Input Parameter:
3281: . snes - the nonlinear solver context
3283: Output Parameters:
3284: + Amat - location to stash (approximate) Jacobian matrix (or `NULL`)
3285: . Pmat - location to stash matrix used to compute the preconditioner (or `NULL`)
3286: . J - location to put Jacobian function (or `NULL`), for calling sequence see `SNESJacobianFn`
3287: - ctx - location to stash Jacobian ctx (or `NULL`)
3289: Level: advanced
3291: .seealso: [](ch_snes), `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFn`, `SNESGetFunction()`
3292: @*/
3293: PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
3294: {
3295: DM dm;
3297: PetscFunctionBegin;
3299: if (Amat) *Amat = snes->jacobian;
3300: if (Pmat) *Pmat = snes->jacobian_pre;
3301: PetscCall(SNESGetDM(snes, &dm));
3302: PetscCall(DMSNESGetJacobian(dm, J, ctx));
3303: PetscFunctionReturn(PETSC_SUCCESS);
3304: }
3306: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3307: {
3308: DM dm;
3309: DMSNES sdm;
3311: PetscFunctionBegin;
3312: PetscCall(SNESGetDM(snes, &dm));
3313: PetscCall(DMGetDMSNES(dm, &sdm));
3314: if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3315: DM dm;
3316: PetscBool isdense, ismf;
3318: PetscCall(SNESGetDM(snes, &dm));
3319: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &isdense, MATSEQDENSE, MATMPIDENSE, MATDENSE, NULL));
3320: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &ismf, MATMFFD, MATSHELL, NULL));
3321: if (isdense) {
3322: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefault, NULL));
3323: } else if (!ismf) {
3324: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefaultColor, NULL));
3325: }
3326: }
3327: PetscFunctionReturn(PETSC_SUCCESS);
3328: }
3330: /*@
3331: SNESSetUp - Sets up the internal data structures for the later use
3332: of a nonlinear solver `SNESSolve()`.
3334: Collective
3336: Input Parameter:
3337: . snes - the `SNES` context
3339: Level: advanced
3341: Note:
3342: For basic use of the `SNES` solvers the user does not need to explicitly call
3343: `SNESSetUp()`, since these actions will automatically occur during
3344: the call to `SNESSolve()`. However, if one wishes to control this
3345: phase separately, `SNESSetUp()` should be called after `SNESCreate()`
3346: and optional routines of the form SNESSetXXX(), but before `SNESSolve()`.
3348: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`, `SNESDestroy()`, `SNESSetFromOptions()`
3349: @*/
3350: PetscErrorCode SNESSetUp(SNES snes)
3351: {
3352: DM dm;
3353: DMSNES sdm;
3354: SNESLineSearch linesearch, pclinesearch;
3355: void *lsprectx, *lspostctx;
3356: PetscBool mf_operator, mf;
3357: Vec f, fpc;
3358: void *funcctx;
3359: void *jacctx, *appctx;
3360: Mat j, jpre;
3361: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, void *);
3362: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *);
3363: SNESFunctionFn *func;
3364: SNESJacobianFn *jac;
3366: PetscFunctionBegin;
3368: if (snes->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
3369: PetscCall(PetscLogEventBegin(SNES_SetUp, snes, 0, 0, 0));
3371: if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, SNESNEWTONLS));
3373: PetscCall(SNESGetFunction(snes, &snes->vec_func, NULL, NULL));
3375: PetscCall(SNESGetDM(snes, &dm));
3376: PetscCall(DMGetDMSNES(dm, &sdm));
3377: PetscCall(SNESSetDefaultComputeJacobian(snes));
3379: if (!snes->vec_func) PetscCall(DMCreateGlobalVector(dm, &snes->vec_func));
3381: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
3383: if (snes->linesearch) {
3384: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
3385: PetscCall(SNESLineSearchSetFunction(snes->linesearch, SNESComputeFunction));
3386: }
3388: PetscCall(SNESGetUseMatrixFree(snes, &mf_operator, &mf));
3389: if (snes->npc && snes->npcside == PC_LEFT) {
3390: snes->mf = PETSC_TRUE;
3391: snes->mf_operator = PETSC_FALSE;
3392: }
3394: if (snes->npc) {
3395: /* copy the DM over */
3396: PetscCall(SNESGetDM(snes, &dm));
3397: PetscCall(SNESSetDM(snes->npc, dm));
3399: PetscCall(SNESGetFunction(snes, &f, &func, &funcctx));
3400: PetscCall(VecDuplicate(f, &fpc));
3401: PetscCall(SNESSetFunction(snes->npc, fpc, func, funcctx));
3402: PetscCall(SNESGetJacobian(snes, &j, &jpre, &jac, &jacctx));
3403: PetscCall(SNESSetJacobian(snes->npc, j, jpre, jac, jacctx));
3404: PetscCall(SNESGetApplicationContext(snes, &appctx));
3405: PetscCall(SNESSetApplicationContext(snes->npc, appctx));
3406: PetscCall(SNESSetUseMatrixFree(snes->npc, mf_operator, mf));
3407: PetscCall(VecDestroy(&fpc));
3409: /* copy the function pointers over */
3410: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)snes->npc));
3412: /* default to 1 iteration */
3413: PetscCall(SNESSetTolerances(snes->npc, 0.0, 0.0, 0.0, 1, snes->npc->max_funcs));
3414: if (snes->npcside == PC_RIGHT) {
3415: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_FINAL_ONLY));
3416: } else {
3417: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_NONE));
3418: }
3419: PetscCall(SNESSetFromOptions(snes->npc));
3421: /* copy the line search context over */
3422: if (snes->linesearch && snes->npc->linesearch) {
3423: PetscCall(SNESGetLineSearch(snes, &linesearch));
3424: PetscCall(SNESGetLineSearch(snes->npc, &pclinesearch));
3425: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
3426: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
3427: PetscCall(SNESLineSearchSetPreCheck(pclinesearch, precheck, lsprectx));
3428: PetscCall(SNESLineSearchSetPostCheck(pclinesearch, postcheck, lspostctx));
3429: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch));
3430: }
3431: }
3432: if (snes->mf) PetscCall(SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version));
3433: if (snes->ops->usercompute && !snes->ctx) PetscCallBack("SNES callback compute application context", (*snes->ops->usercompute)(snes, &snes->ctx));
3435: snes->jac_iter = 0;
3436: snes->pre_iter = 0;
3438: PetscTryTypeMethod(snes, setup);
3440: PetscCall(SNESSetDefaultComputeJacobian(snes));
3442: if (snes->npc && snes->npcside == PC_LEFT) {
3443: if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3444: if (snes->linesearch) {
3445: PetscCall(SNESGetLineSearch(snes, &linesearch));
3446: PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunctionDefaultNPC));
3447: }
3448: }
3449: }
3450: PetscCall(PetscLogEventEnd(SNES_SetUp, snes, 0, 0, 0));
3451: snes->setupcalled = PETSC_TRUE;
3452: PetscFunctionReturn(PETSC_SUCCESS);
3453: }
3455: /*@
3456: 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
3458: Collective
3460: Input Parameter:
3461: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3463: Level: intermediate
3465: Notes:
3466: Any options set on the `SNES` object, including those set with `SNESSetFromOptions()` remain.
3468: Call this if you wish to reuse a `SNES` but with different size vectors
3470: Also calls the application context destroy routine set with `SNESSetComputeApplicationContext()`
3472: .seealso: [](ch_snes), `SNES`, `SNESDestroy()`, `SNESCreate()`, `SNESSetUp()`, `SNESSolve()`
3473: @*/
3474: PetscErrorCode SNESReset(SNES snes)
3475: {
3476: PetscFunctionBegin;
3478: if (snes->ops->ctxdestroy && snes->ctx) {
3479: PetscCallBack("SNES callback destroy application context", (*snes->ops->ctxdestroy)(&snes->ctx));
3480: snes->ctx = NULL;
3481: }
3482: if (snes->npc) PetscCall(SNESReset(snes->npc));
3484: PetscTryTypeMethod(snes, reset);
3485: if (snes->ksp) PetscCall(KSPReset(snes->ksp));
3487: if (snes->linesearch) PetscCall(SNESLineSearchReset(snes->linesearch));
3489: PetscCall(VecDestroy(&snes->vec_rhs));
3490: PetscCall(VecDestroy(&snes->vec_sol));
3491: PetscCall(VecDestroy(&snes->vec_sol_update));
3492: PetscCall(VecDestroy(&snes->vec_func));
3493: PetscCall(MatDestroy(&snes->jacobian));
3494: PetscCall(MatDestroy(&snes->jacobian_pre));
3495: PetscCall(MatDestroy(&snes->picard));
3496: PetscCall(VecDestroyVecs(snes->nwork, &snes->work));
3497: PetscCall(VecDestroyVecs(snes->nvwork, &snes->vwork));
3499: snes->alwayscomputesfinalresidual = PETSC_FALSE;
3501: snes->nwork = snes->nvwork = 0;
3502: snes->setupcalled = PETSC_FALSE;
3503: PetscFunctionReturn(PETSC_SUCCESS);
3504: }
3506: /*@
3507: SNESConvergedReasonViewCancel - Clears all the reason view functions for a `SNES` object provided with `SNESConvergedReasonViewSet()` also
3508: removes the default viewer.
3510: Collective
3512: Input Parameter:
3513: . snes - the nonlinear iterative solver context obtained from `SNESCreate()`
3515: Level: intermediate
3517: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESReset()`, `SNESConvergedReasonViewSet()`
3518: @*/
3519: PetscErrorCode SNESConvergedReasonViewCancel(SNES snes)
3520: {
3521: PetscInt i;
3523: PetscFunctionBegin;
3525: for (i = 0; i < snes->numberreasonviews; i++) {
3526: if (snes->reasonviewdestroy[i]) PetscCall((*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]));
3527: }
3528: snes->numberreasonviews = 0;
3529: PetscCall(PetscViewerDestroy(&snes->convergedreasonviewer));
3530: PetscFunctionReturn(PETSC_SUCCESS);
3531: }
3533: /*@
3534: SNESDestroy - Destroys the nonlinear solver context that was created
3535: with `SNESCreate()`.
3537: Collective
3539: Input Parameter:
3540: . snes - the `SNES` context
3542: Level: beginner
3544: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`
3545: @*/
3546: PetscErrorCode SNESDestroy(SNES *snes)
3547: {
3548: DM dm;
3550: PetscFunctionBegin;
3551: if (!*snes) PetscFunctionReturn(PETSC_SUCCESS);
3553: if (--((PetscObject)*snes)->refct > 0) {
3554: *snes = NULL;
3555: PetscFunctionReturn(PETSC_SUCCESS);
3556: }
3558: PetscCall(SNESReset(*snes));
3559: PetscCall(SNESDestroy(&(*snes)->npc));
3561: /* if memory was published with SAWs then destroy it */
3562: PetscCall(PetscObjectSAWsViewOff((PetscObject)*snes));
3563: PetscTryTypeMethod(*snes, destroy);
3565: dm = (*snes)->dm;
3566: while (dm) {
3567: PetscCall(DMCoarsenHookRemove(dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, *snes));
3568: PetscCall(DMGetCoarseDM(dm, &dm));
3569: }
3571: PetscCall(DMDestroy(&(*snes)->dm));
3572: PetscCall(KSPDestroy(&(*snes)->ksp));
3573: PetscCall(SNESLineSearchDestroy(&(*snes)->linesearch));
3575: PetscCall(PetscFree((*snes)->kspconvctx));
3576: if ((*snes)->ops->convergeddestroy) PetscCall((*(*snes)->ops->convergeddestroy)((*snes)->cnvP));
3577: if ((*snes)->conv_hist_alloc) PetscCall(PetscFree2((*snes)->conv_hist, (*snes)->conv_hist_its));
3578: PetscCall(SNESMonitorCancel(*snes));
3579: PetscCall(SNESConvergedReasonViewCancel(*snes));
3580: PetscCall(PetscHeaderDestroy(snes));
3581: PetscFunctionReturn(PETSC_SUCCESS);
3582: }
3584: /* ----------- Routines to set solver parameters ---------- */
3586: /*@
3587: SNESSetLagPreconditioner - Sets when the preconditioner is rebuilt in the nonlinear solve `SNESSolve()`.
3589: Logically Collective
3591: Input Parameters:
3592: + snes - the `SNES` context
3593: - lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3594: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3596: Options Database Keys:
3597: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3598: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3599: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3600: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3602: Level: intermediate
3604: Notes:
3605: The default is 1
3607: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagPreconditionerPersists()` was called
3609: `SNESSetLagPreconditionerPersists()` allows using the same uniform lagging (for example every second linear solve) across multiple nonlinear solves.
3611: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetLagPreconditionerPersists()`,
3612: `SNESSetLagJacobianPersists()`, `SNES`, `SNESSolve()`
3613: @*/
3614: PetscErrorCode SNESSetLagPreconditioner(SNES snes, PetscInt lag)
3615: {
3616: PetscFunctionBegin;
3618: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3619: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3621: snes->lagpreconditioner = lag;
3622: PetscFunctionReturn(PETSC_SUCCESS);
3623: }
3625: /*@
3626: SNESSetGridSequence - sets the number of steps of grid sequencing that `SNES` will do
3628: Logically Collective
3630: Input Parameters:
3631: + snes - the `SNES` context
3632: - steps - the number of refinements to do, defaults to 0
3634: Options Database Key:
3635: . -snes_grid_sequence <steps> - Use grid sequencing to generate initial guess
3637: Level: intermediate
3639: Notes:
3640: Once grid sequencing is turned on `SNESSolve()` will automatically perform the solve on each grid refinement.
3642: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3644: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetGridSequence()`,
3645: `SNESSetDM()`, `SNESSolve()`
3646: @*/
3647: PetscErrorCode SNESSetGridSequence(SNES snes, PetscInt steps)
3648: {
3649: PetscFunctionBegin;
3652: snes->gridsequence = steps;
3653: PetscFunctionReturn(PETSC_SUCCESS);
3654: }
3656: /*@
3657: SNESGetGridSequence - gets the number of steps of grid sequencing that `SNES` will do
3659: Logically Collective
3661: Input Parameter:
3662: . snes - the `SNES` context
3664: Output Parameter:
3665: . steps - the number of refinements to do, defaults to 0
3667: Level: intermediate
3669: .seealso: [](ch_snes), `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetGridSequence()`
3670: @*/
3671: PetscErrorCode SNESGetGridSequence(SNES snes, PetscInt *steps)
3672: {
3673: PetscFunctionBegin;
3675: *steps = snes->gridsequence;
3676: PetscFunctionReturn(PETSC_SUCCESS);
3677: }
3679: /*@
3680: SNESGetLagPreconditioner - Return how often the preconditioner is rebuilt
3682: Not Collective
3684: Input Parameter:
3685: . snes - the `SNES` context
3687: Output Parameter:
3688: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3689: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3691: Level: intermediate
3693: Notes:
3694: The default is 1
3696: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3698: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3699: @*/
3700: PetscErrorCode SNESGetLagPreconditioner(SNES snes, PetscInt *lag)
3701: {
3702: PetscFunctionBegin;
3704: *lag = snes->lagpreconditioner;
3705: PetscFunctionReturn(PETSC_SUCCESS);
3706: }
3708: /*@
3709: SNESSetLagJacobian - Set when the Jacobian is rebuilt in the nonlinear solve. See `SNESSetLagPreconditioner()` for determining how
3710: often the preconditioner is rebuilt.
3712: Logically Collective
3714: Input Parameters:
3715: + snes - the `SNES` context
3716: - lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3717: the Jacobian is built etc. -2 means rebuild at next chance but then never again
3719: Options Database Keys:
3720: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3721: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3722: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3723: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag.
3725: Level: intermediate
3727: Notes:
3728: The default is 1
3730: The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3732: 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
3733: at the next Newton step but never again (unless it is reset to another value)
3735: .seealso: [](ch_snes), `SNES`, `SNESGetLagPreconditioner()`, `SNESSetLagPreconditioner()`, `SNESGetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3736: @*/
3737: PetscErrorCode SNESSetLagJacobian(SNES snes, PetscInt lag)
3738: {
3739: PetscFunctionBegin;
3741: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3742: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3744: snes->lagjacobian = lag;
3745: PetscFunctionReturn(PETSC_SUCCESS);
3746: }
3748: /*@
3749: SNESGetLagJacobian - Get how often the Jacobian is rebuilt. See `SNESGetLagPreconditioner()` to determine when the preconditioner is rebuilt
3751: Not Collective
3753: Input Parameter:
3754: . snes - the `SNES` context
3756: Output Parameter:
3757: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3758: the Jacobian is built etc.
3760: Level: intermediate
3762: Notes:
3763: The default is 1
3765: The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagJacobianPersists()` was called.
3767: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobian()`, `SNESSetLagPreconditioner()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3769: @*/
3770: PetscErrorCode SNESGetLagJacobian(SNES snes, PetscInt *lag)
3771: {
3772: PetscFunctionBegin;
3774: *lag = snes->lagjacobian;
3775: PetscFunctionReturn(PETSC_SUCCESS);
3776: }
3778: /*@
3779: SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple nonlinear solves
3781: Logically collective
3783: Input Parameters:
3784: + snes - the `SNES` context
3785: - flg - jacobian lagging persists if true
3787: Options Database Keys:
3788: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3789: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3790: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3791: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3793: Level: advanced
3795: Notes:
3796: Normally when `SNESSetLagJacobian()` is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3798: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3799: several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3800: timesteps may present huge efficiency gains.
3802: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditionerPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`
3803: @*/
3804: PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
3805: {
3806: PetscFunctionBegin;
3809: snes->lagjac_persist = flg;
3810: PetscFunctionReturn(PETSC_SUCCESS);
3811: }
3813: /*@
3814: SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves
3816: Logically Collective
3818: Input Parameters:
3819: + snes - the `SNES` context
3820: - flg - preconditioner lagging persists if true
3822: Options Database Keys:
3823: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3824: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3825: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3826: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3828: Level: developer
3830: Notes:
3831: Normally when `SNESSetLagPreconditioner()` is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3833: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3834: by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3835: several timesteps may present huge efficiency gains.
3837: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobianPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagPreconditioner()`
3838: @*/
3839: PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)
3840: {
3841: PetscFunctionBegin;
3844: snes->lagpre_persist = flg;
3845: PetscFunctionReturn(PETSC_SUCCESS);
3846: }
3848: /*@
3849: SNESSetForceIteration - force `SNESSolve()` to take at least one iteration regardless of the initial residual norm
3851: Logically Collective
3853: Input Parameters:
3854: + snes - the `SNES` context
3855: - force - `PETSC_TRUE` require at least one iteration
3857: Options Database Key:
3858: . -snes_force_iteration <force> - Sets forcing an iteration
3860: Level: intermediate
3862: Note:
3863: This is used sometimes with `TS` to prevent `TS` from detecting a false steady state solution
3865: .seealso: [](ch_snes), `SNES`, `TS`, `SNESSetDivergenceTolerance()`
3866: @*/
3867: PetscErrorCode SNESSetForceIteration(SNES snes, PetscBool force)
3868: {
3869: PetscFunctionBegin;
3871: snes->forceiteration = force;
3872: PetscFunctionReturn(PETSC_SUCCESS);
3873: }
3875: /*@
3876: SNESGetForceIteration - Check whether or not `SNESSolve()` take at least one iteration regardless of the initial residual norm
3878: Logically Collective
3880: Input Parameter:
3881: . snes - the `SNES` context
3883: Output Parameter:
3884: . force - `PETSC_TRUE` requires at least one iteration.
3886: Level: intermediate
3888: .seealso: [](ch_snes), `SNES`, `SNESSetForceIteration()`, `SNESSetDivergenceTolerance()`
3889: @*/
3890: PetscErrorCode SNESGetForceIteration(SNES snes, PetscBool *force)
3891: {
3892: PetscFunctionBegin;
3894: *force = snes->forceiteration;
3895: PetscFunctionReturn(PETSC_SUCCESS);
3896: }
3898: /*@
3899: SNESSetTolerances - Sets various parameters used in `SNES` convergence tests.
3901: Logically Collective
3903: Input Parameters:
3904: + snes - the `SNES` context
3905: . abstol - the absolute convergence tolerance, $ F(x^n) \le abstol $
3906: . rtol - the relative convergence tolerance, $ F(x^n) \le reltol * F(x^0) $
3907: . stol - convergence tolerance in terms of the norm of the change in the solution between steps, || delta x || < stol*|| x ||
3908: . maxit - the maximum number of iterations allowed in the solver, default 50.
3909: - maxf - the maximum number of function evaluations allowed in the solver (use `PETSC_UNLIMITED` indicates no limit), default 10,000
3911: Options Database Keys:
3912: + -snes_atol <abstol> - Sets `abstol`
3913: . -snes_rtol <rtol> - Sets `rtol`
3914: . -snes_stol <stol> - Sets `stol`
3915: . -snes_max_it <maxit> - Sets `maxit`
3916: - -snes_max_funcs <maxf> - Sets `maxf` (use `unlimited` to have no maximum)
3918: Level: intermediate
3920: Note:
3921: All parameters must be non-negative
3923: Use `PETSC_CURRENT` to retain the current value of any parameter and `PETSC_DETERMINE` to use the default value for the given `SNES`.
3924: The default value is the value in the object when its type is set.
3926: Use `PETSC_UNLIMITED` on `maxit` or `maxf` to indicate there is no bound on the number of iterations or number of function evaluations.
3928: Fortran Note:
3929: Use `PETSC_CURRENT_INTEGER`, `PETSC_CURRENT_REAL`, `PETSC_UNLIMITED_INTEGER`, `PETSC_DETERMINE_INTEGER`, or `PETSC_DETERMINE_REAL`
3931: .seealso: [](ch_snes), `SNESSolve()`, `SNES`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`
3932: @*/
3933: PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
3934: {
3935: PetscFunctionBegin;
3943: if (abstol == (PetscReal)PETSC_DETERMINE) {
3944: snes->abstol = snes->default_abstol;
3945: } else if (abstol != (PetscReal)PETSC_CURRENT) {
3946: PetscCheck(abstol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %g must be non-negative", (double)abstol);
3947: snes->abstol = abstol;
3948: }
3950: if (rtol == (PetscReal)PETSC_DETERMINE) {
3951: snes->rtol = snes->default_rtol;
3952: } else if (rtol != (PetscReal)PETSC_CURRENT) {
3953: 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);
3954: snes->rtol = rtol;
3955: }
3957: if (stol == (PetscReal)PETSC_DETERMINE) {
3958: snes->stol = snes->default_stol;
3959: } else if (stol != (PetscReal)PETSC_CURRENT) {
3960: PetscCheck(stol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Step tolerance %g must be non-negative", (double)stol);
3961: snes->stol = stol;
3962: }
3964: if (maxit == PETSC_DETERMINE) {
3965: snes->max_its = snes->default_max_its;
3966: } else if (maxit == PETSC_UNLIMITED) {
3967: snes->max_its = PETSC_INT_MAX;
3968: } else if (maxit != PETSC_CURRENT) {
3969: PetscCheck(maxit >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", maxit);
3970: snes->max_its = maxit;
3971: }
3973: if (maxf == PETSC_DETERMINE) {
3974: snes->max_funcs = snes->default_max_funcs;
3975: } else if (maxf == PETSC_UNLIMITED || maxf == -1) {
3976: snes->max_funcs = PETSC_UNLIMITED;
3977: } else if (maxf != PETSC_CURRENT) {
3978: PetscCheck(maxf >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of function evaluations %" PetscInt_FMT " must be nonnegative", maxf);
3979: snes->max_funcs = maxf;
3980: }
3981: PetscFunctionReturn(PETSC_SUCCESS);
3982: }
3984: /*@
3985: SNESSetDivergenceTolerance - Sets the divergence tolerance used for the `SNES` divergence test.
3987: Logically Collective
3989: Input Parameters:
3990: + snes - the `SNES` context
3991: - 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
3992: is stopped due to divergence.
3994: Options Database Key:
3995: . -snes_divergence_tolerance <divtol> - Sets `divtol`
3997: Level: intermediate
3999: Notes:
4000: Use `PETSC_DETERMINE` to use the default value from when the object's type was set.
4002: Fortran Note:
4003: Use ``PETSC_DETERMINE_REAL` or `PETSC_UNLIMITED_REAL`
4005: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetTolerances()`, `SNESGetDivergenceTolerance()`
4006: @*/
4007: PetscErrorCode SNESSetDivergenceTolerance(SNES snes, PetscReal divtol)
4008: {
4009: PetscFunctionBegin;
4013: if (divtol == (PetscReal)PETSC_DETERMINE) {
4014: snes->divtol = snes->default_divtol;
4015: } else if (divtol == (PetscReal)PETSC_UNLIMITED || divtol == -1) {
4016: snes->divtol = PETSC_UNLIMITED;
4017: } else if (divtol != (PetscReal)PETSC_CURRENT) {
4018: PetscCheck(divtol >= 1.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Divergence tolerance %g must be greater than 1.0", (double)divtol);
4019: snes->divtol = divtol;
4020: }
4021: PetscFunctionReturn(PETSC_SUCCESS);
4022: }
4024: /*@
4025: SNESGetTolerances - Gets various parameters used in `SNES` convergence tests.
4027: Not Collective
4029: Input Parameter:
4030: . snes - the `SNES` context
4032: Output Parameters:
4033: + atol - the absolute convergence tolerance
4034: . rtol - the relative convergence tolerance
4035: . stol - convergence tolerance in terms of the norm of the change in the solution between steps
4036: . maxit - the maximum number of iterations allowed
4037: - maxf - the maximum number of function evaluations allowed, `PETSC_UNLIMITED` indicates no bound
4039: Level: intermediate
4041: Notes:
4042: See `SNESSetTolerances()` for details on the parameters.
4044: The user can specify `NULL` for any parameter that is not needed.
4046: .seealso: [](ch_snes), `SNES`, `SNESSetTolerances()`
4047: @*/
4048: PetscErrorCode SNESGetTolerances(SNES snes, PetscReal *atol, PetscReal *rtol, PetscReal *stol, PetscInt *maxit, PetscInt *maxf)
4049: {
4050: PetscFunctionBegin;
4052: if (atol) *atol = snes->abstol;
4053: if (rtol) *rtol = snes->rtol;
4054: if (stol) *stol = snes->stol;
4055: if (maxit) *maxit = snes->max_its;
4056: if (maxf) *maxf = snes->max_funcs;
4057: PetscFunctionReturn(PETSC_SUCCESS);
4058: }
4060: /*@
4061: SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.
4063: Not Collective
4065: Input Parameters:
4066: + snes - the `SNES` context
4067: - divtol - divergence tolerance
4069: Level: intermediate
4071: .seealso: [](ch_snes), `SNES`, `SNESSetDivergenceTolerance()`
4072: @*/
4073: PetscErrorCode SNESGetDivergenceTolerance(SNES snes, PetscReal *divtol)
4074: {
4075: PetscFunctionBegin;
4077: if (divtol) *divtol = snes->divtol;
4078: PetscFunctionReturn(PETSC_SUCCESS);
4079: }
4081: PETSC_INTERN PetscErrorCode SNESMonitorRange_Private(SNES, PetscInt, PetscReal *);
4083: PetscErrorCode SNESMonitorLGRange(SNES snes, PetscInt n, PetscReal rnorm, void *monctx)
4084: {
4085: PetscDrawLG lg;
4086: PetscReal x, y, per;
4087: PetscViewer v = (PetscViewer)monctx;
4088: static PetscReal prev; /* should be in the context */
4089: PetscDraw draw;
4091: PetscFunctionBegin;
4093: PetscCall(PetscViewerDrawGetDrawLG(v, 0, &lg));
4094: if (!n) PetscCall(PetscDrawLGReset(lg));
4095: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4096: PetscCall(PetscDrawSetTitle(draw, "Residual norm"));
4097: x = (PetscReal)n;
4098: if (rnorm > 0.0) y = PetscLog10Real(rnorm);
4099: else y = -15.0;
4100: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4101: if (n < 20 || !(n % 5) || snes->reason) {
4102: PetscCall(PetscDrawLGDraw(lg));
4103: PetscCall(PetscDrawLGSave(lg));
4104: }
4106: PetscCall(PetscViewerDrawGetDrawLG(v, 1, &lg));
4107: if (!n) PetscCall(PetscDrawLGReset(lg));
4108: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4109: PetscCall(PetscDrawSetTitle(draw, "% elements > .2*max element"));
4110: PetscCall(SNESMonitorRange_Private(snes, n, &per));
4111: x = (PetscReal)n;
4112: y = 100.0 * per;
4113: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4114: if (n < 20 || !(n % 5) || snes->reason) {
4115: PetscCall(PetscDrawLGDraw(lg));
4116: PetscCall(PetscDrawLGSave(lg));
4117: }
4119: PetscCall(PetscViewerDrawGetDrawLG(v, 2, &lg));
4120: if (!n) {
4121: prev = rnorm;
4122: PetscCall(PetscDrawLGReset(lg));
4123: }
4124: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4125: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm"));
4126: x = (PetscReal)n;
4127: y = (prev - rnorm) / prev;
4128: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4129: if (n < 20 || !(n % 5) || snes->reason) {
4130: PetscCall(PetscDrawLGDraw(lg));
4131: PetscCall(PetscDrawLGSave(lg));
4132: }
4134: PetscCall(PetscViewerDrawGetDrawLG(v, 3, &lg));
4135: if (!n) PetscCall(PetscDrawLGReset(lg));
4136: PetscCall(PetscDrawLGGetDraw(lg, &draw));
4137: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm*(% > .2 max)"));
4138: x = (PetscReal)n;
4139: y = (prev - rnorm) / (prev * per);
4140: if (n > 2) { /*skip initial crazy value */
4141: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
4142: }
4143: if (n < 20 || !(n % 5) || snes->reason) {
4144: PetscCall(PetscDrawLGDraw(lg));
4145: PetscCall(PetscDrawLGSave(lg));
4146: }
4147: prev = rnorm;
4148: PetscFunctionReturn(PETSC_SUCCESS);
4149: }
4151: /*@
4152: SNESConverged - Run the convergence test and update the `SNESConvergedReason`.
4154: Collective
4156: Input Parameters:
4157: + snes - the `SNES` context
4158: . it - current iteration
4159: . xnorm - 2-norm of current iterate
4160: . snorm - 2-norm of current step
4161: - fnorm - 2-norm of function
4163: Level: developer
4165: Note:
4166: This routine is called by the `SNESSolve()` implementations.
4167: It does not typically need to be called by the user.
4169: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4170: @*/
4171: PetscErrorCode SNESConverged(SNES snes, PetscInt it, PetscReal xnorm, PetscReal snorm, PetscReal fnorm)
4172: {
4173: PetscFunctionBegin;
4174: if (!snes->reason) {
4175: if (snes->normschedule == SNES_NORM_ALWAYS) PetscUseTypeMethod(snes, converged, it, xnorm, snorm, fnorm, &snes->reason, snes->cnvP);
4176: if (it == snes->max_its && !snes->reason) {
4177: if (snes->normschedule == SNES_NORM_ALWAYS) {
4178: PetscCall(PetscInfo(snes, "Maximum number of iterations has been reached: %" PetscInt_FMT "\n", snes->max_its));
4179: snes->reason = SNES_DIVERGED_MAX_IT;
4180: } else snes->reason = SNES_CONVERGED_ITS;
4181: }
4182: }
4183: PetscFunctionReturn(PETSC_SUCCESS);
4184: }
4186: /*@
4187: SNESMonitor - runs any `SNES` monitor routines provided with `SNESMonitor()` or the options database
4189: Collective
4191: Input Parameters:
4192: + snes - nonlinear solver context obtained from `SNESCreate()`
4193: . iter - current iteration number
4194: - rnorm - current relative norm of the residual
4196: Level: developer
4198: Note:
4199: This routine is called by the `SNESSolve()` implementations.
4200: It does not typically need to be called by the user.
4202: .seealso: [](ch_snes), `SNES`, `SNESMonitorSet()`
4203: @*/
4204: PetscErrorCode SNESMonitor(SNES snes, PetscInt iter, PetscReal rnorm)
4205: {
4206: PetscInt i, n = snes->numbermonitors;
4208: PetscFunctionBegin;
4209: PetscCall(VecLockReadPush(snes->vec_sol));
4210: for (i = 0; i < n; i++) PetscCall((*snes->monitor[i])(snes, iter, rnorm, snes->monitorcontext[i]));
4211: PetscCall(VecLockReadPop(snes->vec_sol));
4212: PetscFunctionReturn(PETSC_SUCCESS);
4213: }
4215: /* ------------ Routines to set performance monitoring options ----------- */
4217: /*MC
4218: SNESMonitorFunction - functional form passed to `SNESMonitorSet()` to monitor convergence of nonlinear solver
4220: Synopsis:
4221: #include <petscsnes.h>
4222: PetscErrorCode SNESMonitorFunction(SNES snes, PetscInt its, PetscReal norm, void *mctx)
4224: Collective
4226: Input Parameters:
4227: + snes - the `SNES` context
4228: . its - iteration number
4229: . norm - 2-norm function value (may be estimated)
4230: - mctx - [optional] monitoring context
4232: Level: advanced
4234: .seealso: [](ch_snes), `SNESMonitorSet()`
4235: M*/
4237: /*@C
4238: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
4239: iteration of the `SNES` nonlinear solver to display the iteration's
4240: progress.
4242: Logically Collective
4244: Input Parameters:
4245: + snes - the `SNES` context
4246: . f - the monitor function, for the calling sequence see `SNESMonitorFunction`
4247: . mctx - [optional] user-defined context for private data for the monitor routine (use `NULL` if no context is desired)
4248: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4250: Options Database Keys:
4251: + -snes_monitor - sets `SNESMonitorDefault()`
4252: . -snes_monitor draw::draw_lg - sets line graph monitor,
4253: - -snes_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `SNESMonitorSet()`, but does not cancel those set via
4254: the options database.
4256: Level: intermediate
4258: Note:
4259: Several different monitoring routines may be set by calling
4260: `SNESMonitorSet()` multiple times; all will be called in the
4261: order in which they were set.
4263: Fortran Note:
4264: Only a single monitor function can be set for each `SNES` object
4266: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESMonitorDefault()`, `SNESMonitorCancel()`, `SNESMonitorFunction`, `PetscCtxDestroyFn`
4267: @*/
4268: PetscErrorCode SNESMonitorSet(SNES snes, PetscErrorCode (*f)(SNES, PetscInt, PetscReal, void *), void *mctx, PetscCtxDestroyFn *monitordestroy)
4269: {
4270: PetscFunctionBegin;
4272: for (PetscInt i = 0; i < snes->numbermonitors; i++) {
4273: PetscBool identical;
4275: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))(PetscVoidFn *)f, mctx, monitordestroy, (PetscErrorCode (*)(void))(PetscVoidFn *)snes->monitor[i], snes->monitorcontext[i], snes->monitordestroy[i], &identical));
4276: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4277: }
4278: PetscCheck(snes->numbermonitors < MAXSNESMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
4279: snes->monitor[snes->numbermonitors] = f;
4280: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
4281: snes->monitorcontext[snes->numbermonitors++] = mctx;
4282: PetscFunctionReturn(PETSC_SUCCESS);
4283: }
4285: /*@
4286: SNESMonitorCancel - Clears all the monitor functions for a `SNES` object.
4288: Logically Collective
4290: Input Parameter:
4291: . snes - the `SNES` context
4293: Options Database Key:
4294: . -snes_monitor_cancel - cancels all monitors that have been hardwired
4295: into a code by calls to `SNESMonitorSet()`, but does not cancel those
4296: set via the options database
4298: Level: intermediate
4300: Note:
4301: There is no way to clear one specific monitor from a `SNES` object.
4303: .seealso: [](ch_snes), `SNES`, `SNESMonitorDefault()`, `SNESMonitorSet()`
4304: @*/
4305: PetscErrorCode SNESMonitorCancel(SNES snes)
4306: {
4307: PetscInt i;
4309: PetscFunctionBegin;
4311: for (i = 0; i < snes->numbermonitors; i++) {
4312: if (snes->monitordestroy[i]) PetscCall((*snes->monitordestroy[i])(&snes->monitorcontext[i]));
4313: }
4314: snes->numbermonitors = 0;
4315: PetscFunctionReturn(PETSC_SUCCESS);
4316: }
4318: /*MC
4319: SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver
4321: Synopsis:
4322: #include <petscsnes.h>
4323: PetscErrorCode SNESConvergenceTest(SNES snes, PetscInt it, PetscReal xnorm, PetscReal gnorm, PetscReal f, SNESConvergedReason *reason, void *cctx)
4325: Collective
4327: Input Parameters:
4328: + snes - the `SNES` context
4329: . it - current iteration (0 is the first and is before any Newton step)
4330: . xnorm - 2-norm of current iterate
4331: . gnorm - 2-norm of current step
4332: . f - 2-norm of function
4333: - cctx - [optional] convergence context
4335: Output Parameter:
4336: . reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected
4338: Level: intermediate
4340: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`
4341: M*/
4343: /*@C
4344: SNESSetConvergenceTest - Sets the function that is to be used
4345: to test for convergence of the nonlinear iterative solution.
4347: Logically Collective
4349: Input Parameters:
4350: + snes - the `SNES` context
4351: . SNESConvergenceTestFunction - routine to test for convergence
4352: . cctx - [optional] context for private data for the convergence routine (may be `NULL`)
4353: - destroy - [optional] destructor for the context (may be `NULL`; `PETSC_NULL_FUNCTION` in Fortran)
4355: Level: advanced
4357: .seealso: [](ch_snes), `SNES`, `SNESConvergedDefault()`, `SNESConvergedSkip()`, `SNESConvergenceTestFunction`
4358: @*/
4359: PetscErrorCode SNESSetConvergenceTest(SNES snes, PetscErrorCode (*SNESConvergenceTestFunction)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *cctx, PetscErrorCode (*destroy)(void *))
4360: {
4361: PetscFunctionBegin;
4363: if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4364: if (snes->ops->convergeddestroy) PetscCall((*snes->ops->convergeddestroy)(snes->cnvP));
4365: snes->ops->converged = SNESConvergenceTestFunction;
4366: snes->ops->convergeddestroy = destroy;
4367: snes->cnvP = cctx;
4368: PetscFunctionReturn(PETSC_SUCCESS);
4369: }
4371: /*@
4372: SNESGetConvergedReason - Gets the reason the `SNES` iteration was stopped, which may be due to convergence, divergence, or stagnation
4374: Not Collective
4376: Input Parameter:
4377: . snes - the `SNES` context
4379: Output Parameter:
4380: . reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` for the individual convergence tests for complete lists
4382: Options Database Key:
4383: . -snes_converged_reason - prints the reason to standard out
4385: Level: intermediate
4387: Note:
4388: Should only be called after the call the `SNESSolve()` is complete, if it is called earlier it returns the value `SNES__CONVERGED_ITERATING`.
4390: .seealso: [](ch_snes), `SNESSolve()`, `SNESSetConvergenceTest()`, `SNESSetConvergedReason()`, `SNESConvergedReason`, `SNESGetConvergedReasonString()`
4391: @*/
4392: PetscErrorCode SNESGetConvergedReason(SNES snes, SNESConvergedReason *reason)
4393: {
4394: PetscFunctionBegin;
4396: PetscAssertPointer(reason, 2);
4397: *reason = snes->reason;
4398: PetscFunctionReturn(PETSC_SUCCESS);
4399: }
4401: /*@C
4402: SNESGetConvergedReasonString - Return a human readable string for `SNESConvergedReason`
4404: Not Collective
4406: Input Parameter:
4407: . snes - the `SNES` context
4409: Output Parameter:
4410: . strreason - a human readable string that describes `SNES` converged reason
4412: Level: beginner
4414: .seealso: [](ch_snes), `SNES`, `SNESGetConvergedReason()`
4415: @*/
4416: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char **strreason)
4417: {
4418: PetscFunctionBegin;
4420: PetscAssertPointer(strreason, 2);
4421: *strreason = SNESConvergedReasons[snes->reason];
4422: PetscFunctionReturn(PETSC_SUCCESS);
4423: }
4425: /*@
4426: SNESSetConvergedReason - Sets the reason the `SNES` iteration was stopped.
4428: Not Collective
4430: Input Parameters:
4431: + snes - the `SNES` context
4432: - reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` or the
4433: manual pages for the individual convergence tests for complete lists
4435: Level: developer
4437: Developer Note:
4438: Called inside the various `SNESSolve()` implementations
4440: .seealso: [](ch_snes), `SNESGetConvergedReason()`, `SNESSetConvergenceTest()`, `SNESConvergedReason`
4441: @*/
4442: PetscErrorCode SNESSetConvergedReason(SNES snes, SNESConvergedReason reason)
4443: {
4444: PetscFunctionBegin;
4446: PetscCheck(!snes->errorifnotconverged || reason > 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_PLIB, "SNES code should have previously errored due to negative reason");
4447: snes->reason = reason;
4448: PetscFunctionReturn(PETSC_SUCCESS);
4449: }
4451: /*@
4452: SNESSetConvergenceHistory - Sets the arrays used to hold the convergence history.
4454: Logically Collective
4456: Input Parameters:
4457: + snes - iterative context obtained from `SNESCreate()`
4458: . a - array to hold history, this array will contain the function norms computed at each step
4459: . its - integer array holds the number of linear iterations for each solve.
4460: . na - size of `a` and `its`
4461: - reset - `PETSC_TRUE` indicates each new nonlinear solve resets the history counter to zero,
4462: else it continues storing new values for new nonlinear solves after the old ones
4464: Level: intermediate
4466: Notes:
4467: If 'a' and 'its' are `NULL` then space is allocated for the history. If 'na' is `PETSC_DECIDE` (or, deprecated, `PETSC_DEFAULT`) then a
4468: default array of length 1,000 is allocated.
4470: This routine is useful, e.g., when running a code for purposes
4471: of accurate performance monitoring, when no I/O should be done
4472: during the section of code that is being timed.
4474: If the arrays run out of space after a number of iterations then the later values are not saved in the history
4476: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergenceHistory()`
4477: @*/
4478: PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)
4479: {
4480: PetscFunctionBegin;
4482: if (a) PetscAssertPointer(a, 2);
4483: if (its) PetscAssertPointer(its, 3);
4484: if (!a) {
4485: if (na == PETSC_DECIDE) na = 1000;
4486: PetscCall(PetscCalloc2(na, &a, na, &its));
4487: snes->conv_hist_alloc = PETSC_TRUE;
4488: }
4489: snes->conv_hist = a;
4490: snes->conv_hist_its = its;
4491: snes->conv_hist_max = (size_t)na;
4492: snes->conv_hist_len = 0;
4493: snes->conv_hist_reset = reset;
4494: PetscFunctionReturn(PETSC_SUCCESS);
4495: }
4497: #if defined(PETSC_HAVE_MATLAB)
4498: #include <engine.h> /* MATLAB include file */
4499: #include <mex.h> /* MATLAB include file */
4501: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4502: {
4503: mxArray *mat;
4504: PetscInt i;
4505: PetscReal *ar;
4507: mat = mxCreateDoubleMatrix(snes->conv_hist_len, 1, mxREAL);
4508: ar = (PetscReal *)mxGetData(mat);
4509: for (i = 0; i < snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4510: return mat;
4511: }
4512: #endif
4514: /*@C
4515: SNESGetConvergenceHistory - Gets the arrays used to hold the convergence history.
4517: Not Collective
4519: Input Parameter:
4520: . snes - iterative context obtained from `SNESCreate()`
4522: Output Parameters:
4523: + a - array to hold history, usually was set with `SNESSetConvergenceHistory()`
4524: . its - integer array holds the number of linear iterations (or
4525: negative if not converged) for each solve.
4526: - na - size of `a` and `its`
4528: Level: intermediate
4530: Note:
4531: This routine is useful, e.g., when running a code for purposes
4532: of accurate performance monitoring, when no I/O should be done
4533: during the section of code that is being timed.
4535: Fortran Notes:
4536: Return the arrays with ``SNESRestoreConvergenceHistory()`
4538: Use the arguments
4539: .vb
4540: PetscReal, pointer :: a(:)
4541: PetscInt, pointer :: its(:)
4542: .ve
4544: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetConvergenceHistory()`
4545: @*/
4546: PetscErrorCode SNESGetConvergenceHistory(SNES snes, PetscReal *a[], PetscInt *its[], PetscInt *na)
4547: {
4548: PetscFunctionBegin;
4550: if (a) *a = snes->conv_hist;
4551: if (its) *its = snes->conv_hist_its;
4552: if (na) *na = (PetscInt)snes->conv_hist_len;
4553: PetscFunctionReturn(PETSC_SUCCESS);
4554: }
4556: /*@C
4557: SNESSetUpdate - Sets the general-purpose update function called
4558: at the beginning of every iteration of the nonlinear solve. Specifically
4559: it is called just before the Jacobian is "evaluated" and after the function
4560: evaluation.
4562: Logically Collective
4564: Input Parameters:
4565: + snes - The nonlinear solver context
4566: - func - The update function; for calling sequence see `SNESUpdateFn`
4568: Level: advanced
4570: Notes:
4571: 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
4572: to `SNESSetFunction()`, or `SNESSetPicard()`
4573: This is not used by most users, and it is intended to provide a general hook that is run
4574: right before the direction step is computed.
4576: Users are free to modify the current residual vector,
4577: the current linearization point, or any other vector associated to the specific solver used.
4578: If such modifications take place, it is the user responsibility to update all the relevant
4579: vectors. For example, if one is adjusting the model parameters at each Newton step their code may look like
4580: .vb
4581: PetscErrorCode update(SNES snes, PetscInt iteration)
4582: {
4583: PetscFunctionBeginUser;
4584: if (iteration > 0) {
4585: // update the model parameters here
4586: Vec x,f;
4587: PetscCall(SNESGetSolution(snes,&x));
4588: PetcCall(SNESGetFunction(snes,&f,NULL,NULL));
4589: PetscCall(SNESComputeFunction(snes,x,f));
4590: }
4591: PetscFunctionReturn(PETSC_SUCCESS);
4592: }
4593: .ve
4595: 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.
4597: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetJacobian()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRSetPostCheck()`,
4598: `SNESMonitorSet()`
4599: @*/
4600: PetscErrorCode SNESSetUpdate(SNES snes, SNESUpdateFn *func)
4601: {
4602: PetscFunctionBegin;
4604: snes->ops->update = func;
4605: PetscFunctionReturn(PETSC_SUCCESS);
4606: }
4608: /*@
4609: SNESConvergedReasonView - Displays the reason a `SNES` solve converged or diverged to a viewer
4611: Collective
4613: Input Parameters:
4614: + snes - iterative context obtained from `SNESCreate()`
4615: - viewer - the viewer to display the reason
4617: Options Database Keys:
4618: + -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4619: - -snes_converged_reason ::failed - only print reason and number of iterations when diverged
4621: Level: beginner
4623: Note:
4624: To change the format of the output call `PetscViewerPushFormat`(viewer,format) before this call. Use `PETSC_VIEWER_DEFAULT` for the default,
4625: use `PETSC_VIEWER_FAILED` to only display a reason if it fails.
4627: .seealso: [](ch_snes), `SNESConvergedReason`, `PetscViewer`, `SNES`,
4628: `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`, `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`,
4629: `SNESConvergedReasonViewFromOptions()`,
4630: `PetscViewerPushFormat()`, `PetscViewerPopFormat()`
4631: @*/
4632: PetscErrorCode SNESConvergedReasonView(SNES snes, PetscViewer viewer)
4633: {
4634: PetscViewerFormat format;
4635: PetscBool isAscii;
4637: PetscFunctionBegin;
4638: if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4639: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isAscii));
4640: if (isAscii) {
4641: PetscCall(PetscViewerGetFormat(viewer, &format));
4642: PetscCall(PetscViewerASCIIAddTab(viewer, ((PetscObject)snes)->tablevel + 1));
4643: if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4644: DM dm;
4645: Vec u;
4646: PetscDS prob;
4647: PetscInt Nf, f;
4648: PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4649: void **exactCtx;
4650: PetscReal error;
4652: PetscCall(SNESGetDM(snes, &dm));
4653: PetscCall(SNESGetSolution(snes, &u));
4654: PetscCall(DMGetDS(dm, &prob));
4655: PetscCall(PetscDSGetNumFields(prob, &Nf));
4656: PetscCall(PetscMalloc2(Nf, &exactSol, Nf, &exactCtx));
4657: for (f = 0; f < Nf; ++f) PetscCall(PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]));
4658: PetscCall(DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error));
4659: PetscCall(PetscFree2(exactSol, exactCtx));
4660: if (error < 1.0e-11) PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n"));
4661: else PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", (double)error));
4662: }
4663: if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4664: if (((PetscObject)snes)->prefix) {
4665: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve converged due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4666: } else {
4667: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve converged due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4668: }
4669: } else if (snes->reason <= 0) {
4670: if (((PetscObject)snes)->prefix) {
4671: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve did not converge due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4672: } else {
4673: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve did not converge due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4674: }
4675: }
4676: PetscCall(PetscViewerASCIISubtractTab(viewer, ((PetscObject)snes)->tablevel + 1));
4677: }
4678: PetscFunctionReturn(PETSC_SUCCESS);
4679: }
4681: /*@C
4682: SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4683: end of the nonlinear solver to display the convergence reason of the nonlinear solver.
4685: Logically Collective
4687: Input Parameters:
4688: + snes - the `SNES` context
4689: . f - the `SNESConvergedReason` view function
4690: . vctx - [optional] user-defined context for private data for the `SNESConvergedReason` view function (use `NULL` if no context is desired)
4691: - reasonviewdestroy - [optional] routine that frees the context (may be `NULL`), see `PetscCtxDestroyFn` for the calling sequence
4693: Calling sequence of `f`:
4694: + snes - the `SNES` context
4695: - vctx - [optional] context for private data for the function
4697: Options Database Keys:
4698: + -snes_converged_reason - sets a default `SNESConvergedReasonView()`
4699: - -snes_converged_reason_view_cancel - cancels all converged reason viewers that have been hardwired into a code by
4700: calls to `SNESConvergedReasonViewSet()`, but does not cancel those set via the options database.
4702: Level: intermediate
4704: Note:
4705: Several different converged reason view routines may be set by calling
4706: `SNESConvergedReasonViewSet()` multiple times; all will be called in the
4707: order in which they were set.
4709: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESConvergedReason`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`, `SNESConvergedReasonViewCancel()`,
4710: `PetscCtxDestroyFn`
4711: @*/
4712: PetscErrorCode SNESConvergedReasonViewSet(SNES snes, PetscErrorCode (*f)(SNES snes, void *vctx), void *vctx, PetscCtxDestroyFn *reasonviewdestroy)
4713: {
4714: PetscFunctionBegin;
4716: for (PetscInt i = 0; i < snes->numberreasonviews; i++) {
4717: PetscBool identical;
4719: PetscCall(PetscMonitorCompare((PetscErrorCode (*)(void))(PetscVoidFn *)f, vctx, reasonviewdestroy, (PetscErrorCode (*)(void))(PetscVoidFn *)snes->reasonview[i], snes->reasonviewcontext[i], snes->reasonviewdestroy[i], &identical));
4720: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4721: }
4722: PetscCheck(snes->numberreasonviews < MAXSNESREASONVIEWS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many SNES reasonview set");
4723: snes->reasonview[snes->numberreasonviews] = f;
4724: snes->reasonviewdestroy[snes->numberreasonviews] = reasonviewdestroy;
4725: snes->reasonviewcontext[snes->numberreasonviews++] = vctx;
4726: PetscFunctionReturn(PETSC_SUCCESS);
4727: }
4729: /*@
4730: SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a `SNESConvergedReason` is to be viewed at the end of `SNESSolve()`
4731: All the user-provided viewer routines set with `SNESConvergedReasonViewSet()` will be called, if they exist.
4733: Collective
4735: Input Parameter:
4736: . snes - the `SNES` object
4738: Level: advanced
4740: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESConvergedReasonViewSet()`, `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`,
4741: `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`
4742: @*/
4743: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4744: {
4745: static PetscBool incall = PETSC_FALSE;
4747: PetscFunctionBegin;
4748: if (incall) PetscFunctionReturn(PETSC_SUCCESS);
4749: incall = PETSC_TRUE;
4751: /* All user-provided viewers are called first, if they exist. */
4752: for (PetscInt i = 0; i < snes->numberreasonviews; i++) PetscCall((*snes->reasonview[i])(snes, snes->reasonviewcontext[i]));
4754: /* Call PETSc default routine if users ask for it */
4755: if (snes->convergedreasonviewer) {
4756: PetscCall(PetscViewerPushFormat(snes->convergedreasonviewer, snes->convergedreasonformat));
4757: PetscCall(SNESConvergedReasonView(snes, snes->convergedreasonviewer));
4758: PetscCall(PetscViewerPopFormat(snes->convergedreasonviewer));
4759: }
4760: incall = PETSC_FALSE;
4761: PetscFunctionReturn(PETSC_SUCCESS);
4762: }
4764: /*@
4765: SNESSolve - Solves a nonlinear system $F(x) = b $ associated with a `SNES` object
4767: Collective
4769: Input Parameters:
4770: + snes - the `SNES` context
4771: . b - the constant part of the equation $F(x) = b$, or `NULL` to use zero.
4772: - x - the solution vector.
4774: Level: beginner
4776: Note:
4777: The user should initialize the vector, `x`, with the initial guess
4778: for the nonlinear solve prior to calling `SNESSolve()` .
4780: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFunction()`, `SNESSetJacobian()`, `SNESSetGridSequence()`, `SNESGetSolution()`,
4781: `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRGetPreCheck()`, `SNESNewtonTRSetPostCheck()`, `SNESNewtonTRGetPostCheck()`,
4782: `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`
4783: @*/
4784: PetscErrorCode SNESSolve(SNES snes, Vec b, Vec x)
4785: {
4786: PetscBool flg;
4787: PetscInt grid;
4788: Vec xcreated = NULL;
4789: DM dm;
4791: PetscFunctionBegin;
4794: if (x) PetscCheckSameComm(snes, 1, x, 3);
4796: if (b) PetscCheckSameComm(snes, 1, b, 2);
4798: /* High level operations using the nonlinear solver */
4799: {
4800: PetscViewer viewer;
4801: PetscViewerFormat format;
4802: PetscInt num;
4803: PetscBool flg;
4804: static PetscBool incall = PETSC_FALSE;
4806: if (!incall) {
4807: /* Estimate the convergence rate of the discretization */
4808: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg));
4809: if (flg) {
4810: PetscConvEst conv;
4811: DM dm;
4812: PetscReal *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4813: PetscInt Nf;
4815: incall = PETSC_TRUE;
4816: PetscCall(SNESGetDM(snes, &dm));
4817: PetscCall(DMGetNumFields(dm, &Nf));
4818: PetscCall(PetscCalloc1(Nf, &alpha));
4819: PetscCall(PetscConvEstCreate(PetscObjectComm((PetscObject)snes), &conv));
4820: PetscCall(PetscConvEstSetSolver(conv, (PetscObject)snes));
4821: PetscCall(PetscConvEstSetFromOptions(conv));
4822: PetscCall(PetscConvEstSetUp(conv));
4823: PetscCall(PetscConvEstGetConvRate(conv, alpha));
4824: PetscCall(PetscViewerPushFormat(viewer, format));
4825: PetscCall(PetscConvEstRateView(conv, alpha, viewer));
4826: PetscCall(PetscViewerPopFormat(viewer));
4827: PetscCall(PetscViewerDestroy(&viewer));
4828: PetscCall(PetscConvEstDestroy(&conv));
4829: PetscCall(PetscFree(alpha));
4830: incall = PETSC_FALSE;
4831: }
4832: /* Adaptively refine the initial grid */
4833: num = 1;
4834: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_initial", &num, &flg));
4835: if (flg) {
4836: DMAdaptor adaptor;
4838: incall = PETSC_TRUE;
4839: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4840: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4841: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4842: PetscCall(DMAdaptorSetFromOptions(adaptor));
4843: PetscCall(DMAdaptorSetUp(adaptor));
4844: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x));
4845: PetscCall(DMAdaptorDestroy(&adaptor));
4846: incall = PETSC_FALSE;
4847: }
4848: /* Use grid sequencing to adapt */
4849: num = 0;
4850: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_sequence", &num, NULL));
4851: if (num) {
4852: DMAdaptor adaptor;
4853: const char *prefix;
4855: incall = PETSC_TRUE;
4856: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4857: PetscCall(SNESGetOptionsPrefix(snes, &prefix));
4858: PetscCall(DMAdaptorSetOptionsPrefix(adaptor, prefix));
4859: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4860: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4861: PetscCall(DMAdaptorSetFromOptions(adaptor));
4862: PetscCall(DMAdaptorSetUp(adaptor));
4863: PetscCall(PetscObjectViewFromOptions((PetscObject)adaptor, NULL, "-snes_adapt_view"));
4864: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x));
4865: PetscCall(DMAdaptorDestroy(&adaptor));
4866: incall = PETSC_FALSE;
4867: }
4868: }
4869: }
4870: if (!x) x = snes->vec_sol;
4871: if (!x) {
4872: PetscCall(SNESGetDM(snes, &dm));
4873: PetscCall(DMCreateGlobalVector(dm, &xcreated));
4874: x = xcreated;
4875: }
4876: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view_pre"));
4878: for (grid = 0; grid < snes->gridsequence; grid++) PetscCall(PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4879: for (grid = 0; grid < snes->gridsequence + 1; grid++) {
4880: /* set solution vector */
4881: if (!grid) PetscCall(PetscObjectReference((PetscObject)x));
4882: PetscCall(VecDestroy(&snes->vec_sol));
4883: snes->vec_sol = x;
4884: PetscCall(SNESGetDM(snes, &dm));
4886: /* set affine vector if provided */
4887: if (b) PetscCall(PetscObjectReference((PetscObject)b));
4888: PetscCall(VecDestroy(&snes->vec_rhs));
4889: snes->vec_rhs = b;
4891: 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");
4892: PetscCheck(snes->vec_func != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be function vector");
4893: PetscCheck(snes->vec_rhs != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be right-hand side vector");
4894: if (!snes->vec_sol_update /* && snes->vec_sol */) PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_sol_update));
4895: PetscCall(DMShellSetGlobalVector(dm, snes->vec_sol));
4896: PetscCall(SNESSetUp(snes));
4898: if (!grid) {
4899: if (snes->ops->computeinitialguess) PetscCallBack("SNES callback compute initial guess", (*snes->ops->computeinitialguess)(snes, snes->vec_sol, snes->initialguessP));
4900: }
4902: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4903: PetscCall(SNESResetCounters(snes));
4904: snes->reason = SNES_CONVERGED_ITERATING;
4905: PetscCall(PetscLogEventBegin(SNES_Solve, snes, 0, 0, 0));
4906: PetscUseTypeMethod(snes, solve);
4907: PetscCall(PetscLogEventEnd(SNES_Solve, snes, 0, 0, 0));
4908: PetscCheck(snes->reason, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Internal error, solver %s returned without setting converged reason", ((PetscObject)snes)->type_name);
4909: snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */
4911: if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4912: if (snes->lagpre_persist) snes->pre_iter += snes->iter;
4914: PetscCall(PetscOptionsCreateViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_test_local_min", NULL, NULL, &flg));
4915: if (flg && !PetscPreLoadingOn) PetscCall(SNESTestLocalMin(snes));
4916: /* Call converged reason views. This may involve user-provided viewers as well */
4917: PetscCall(SNESConvergedReasonViewFromOptions(snes));
4919: if (snes->errorifnotconverged) PetscCheck(snes->reason >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_NOT_CONVERGED, "SNESSolve has not converged");
4920: if (snes->reason < 0) break;
4921: if (grid < snes->gridsequence) {
4922: DM fine;
4923: Vec xnew;
4924: Mat interp;
4926: PetscCall(DMRefine(snes->dm, PetscObjectComm((PetscObject)snes), &fine));
4927: PetscCheck(fine, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "DMRefine() did not perform any refinement, cannot continue grid sequencing");
4928: PetscCall(DMGetCoordinatesLocalSetUp(fine));
4929: PetscCall(DMCreateInterpolation(snes->dm, fine, &interp, NULL));
4930: PetscCall(DMCreateGlobalVector(fine, &xnew));
4931: PetscCall(MatInterpolate(interp, x, xnew));
4932: PetscCall(DMInterpolate(snes->dm, interp, fine));
4933: PetscCall(MatDestroy(&interp));
4934: x = xnew;
4936: PetscCall(SNESReset(snes));
4937: PetscCall(SNESSetDM(snes, fine));
4938: PetscCall(SNESResetFromOptions(snes));
4939: PetscCall(DMDestroy(&fine));
4940: PetscCall(PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4941: }
4942: }
4943: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view"));
4944: PetscCall(VecViewFromOptions(snes->vec_sol, (PetscObject)snes, "-snes_view_solution"));
4945: PetscCall(DMMonitor(snes->dm));
4946: PetscCall(SNESMonitorPauseFinal_Internal(snes));
4948: PetscCall(VecDestroy(&xcreated));
4949: PetscCall(PetscObjectSAWsBlock((PetscObject)snes));
4950: PetscFunctionReturn(PETSC_SUCCESS);
4951: }
4953: /* --------- Internal routines for SNES Package --------- */
4955: /*@
4956: SNESSetType - Sets the algorithm/method to be used to solve the nonlinear system with the given `SNES`
4958: Collective
4960: Input Parameters:
4961: + snes - the `SNES` context
4962: - type - a known method
4964: Options Database Key:
4965: . -snes_type <type> - Sets the method; use -help for a list
4966: of available methods (for instance, newtonls or newtontr)
4968: Level: intermediate
4970: Notes:
4971: See `SNESType` for available methods (for instance)
4972: + `SNESNEWTONLS` - Newton's method with line search
4973: (systems of nonlinear equations)
4974: - `SNESNEWTONTR` - Newton's method with trust region
4975: (systems of nonlinear equations)
4977: Normally, it is best to use the `SNESSetFromOptions()` command and then
4978: set the `SNES` solver type from the options database rather than by using
4979: this routine. Using the options database provides the user with
4980: maximum flexibility in evaluating the many nonlinear solvers.
4981: The `SNESSetType()` routine is provided for those situations where it
4982: is necessary to set the nonlinear solver independently of the command
4983: line or options database. This might be the case, for example, when
4984: the choice of solver changes during the execution of the program,
4985: and the user's application is taking responsibility for choosing the
4986: appropriate method.
4988: Developer Note:
4989: `SNESRegister()` adds a constructor for a new `SNESType` to `SNESList`, `SNESSetType()` locates
4990: the constructor in that list and calls it to create the specific object.
4992: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESType`, `SNESCreate()`, `SNESDestroy()`, `SNESGetType()`, `SNESSetFromOptions()`
4993: @*/
4994: PetscErrorCode SNESSetType(SNES snes, SNESType type)
4995: {
4996: PetscBool match;
4997: PetscErrorCode (*r)(SNES);
4999: PetscFunctionBegin;
5001: PetscAssertPointer(type, 2);
5003: PetscCall(PetscObjectTypeCompare((PetscObject)snes, type, &match));
5004: if (match) PetscFunctionReturn(PETSC_SUCCESS);
5006: PetscCall(PetscFunctionListFind(SNESList, type, &r));
5007: PetscCheck(r, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested SNES type %s", type);
5008: /* Destroy the previous private SNES context */
5009: PetscTryTypeMethod(snes, destroy);
5010: /* Reinitialize type-specific function pointers in SNESOps structure */
5011: snes->ops->reset = NULL;
5012: snes->ops->setup = NULL;
5013: snes->ops->solve = NULL;
5014: snes->ops->view = NULL;
5015: snes->ops->setfromoptions = NULL;
5016: snes->ops->destroy = NULL;
5018: /* It may happen the user has customized the line search before calling SNESSetType */
5019: if (((PetscObject)snes)->type_name) PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5021: /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
5022: snes->setupcalled = PETSC_FALSE;
5024: PetscCall(PetscObjectChangeTypeName((PetscObject)snes, type));
5025: PetscCall((*r)(snes));
5026: PetscFunctionReturn(PETSC_SUCCESS);
5027: }
5029: /*@
5030: SNESGetType - Gets the `SNES` method type and name (as a string).
5032: Not Collective
5034: Input Parameter:
5035: . snes - nonlinear solver context
5037: Output Parameter:
5038: . type - `SNES` method (a character string)
5040: Level: intermediate
5042: .seealso: [](ch_snes), `SNESSetType()`, `SNESType`, `SNESSetFromOptions()`, `SNES`
5043: @*/
5044: PetscErrorCode SNESGetType(SNES snes, SNESType *type)
5045: {
5046: PetscFunctionBegin;
5048: PetscAssertPointer(type, 2);
5049: *type = ((PetscObject)snes)->type_name;
5050: PetscFunctionReturn(PETSC_SUCCESS);
5051: }
5053: /*@
5054: SNESSetSolution - Sets the solution vector for use by the `SNES` routines.
5056: Logically Collective
5058: Input Parameters:
5059: + snes - the `SNES` context obtained from `SNESCreate()`
5060: - u - the solution vector
5062: Level: beginner
5064: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetSolution()`, `Vec`
5065: @*/
5066: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
5067: {
5068: DM dm;
5070: PetscFunctionBegin;
5073: PetscCall(PetscObjectReference((PetscObject)u));
5074: PetscCall(VecDestroy(&snes->vec_sol));
5076: snes->vec_sol = u;
5078: PetscCall(SNESGetDM(snes, &dm));
5079: PetscCall(DMShellSetGlobalVector(dm, u));
5080: PetscFunctionReturn(PETSC_SUCCESS);
5081: }
5083: /*@
5084: SNESGetSolution - Returns the vector where the approximate solution is
5085: stored. This is the fine grid solution when using `SNESSetGridSequence()`.
5087: Not Collective, but `x` is parallel if `snes` is parallel
5089: Input Parameter:
5090: . snes - the `SNES` context
5092: Output Parameter:
5093: . x - the solution
5095: Level: intermediate
5097: .seealso: [](ch_snes), `SNESSetSolution()`, `SNESSolve()`, `SNES`, `SNESGetSolutionUpdate()`, `SNESGetFunction()`
5098: @*/
5099: PetscErrorCode SNESGetSolution(SNES snes, Vec *x)
5100: {
5101: PetscFunctionBegin;
5103: PetscAssertPointer(x, 2);
5104: *x = snes->vec_sol;
5105: PetscFunctionReturn(PETSC_SUCCESS);
5106: }
5108: /*@
5109: SNESGetSolutionUpdate - Returns the vector where the solution update is
5110: stored.
5112: Not Collective, but `x` is parallel if `snes` is parallel
5114: Input Parameter:
5115: . snes - the `SNES` context
5117: Output Parameter:
5118: . x - the solution update
5120: Level: advanced
5122: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`
5123: @*/
5124: PetscErrorCode SNESGetSolutionUpdate(SNES snes, Vec *x)
5125: {
5126: PetscFunctionBegin;
5128: PetscAssertPointer(x, 2);
5129: *x = snes->vec_sol_update;
5130: PetscFunctionReturn(PETSC_SUCCESS);
5131: }
5133: /*@C
5134: SNESGetFunction - Returns the function that defines the nonlinear system set with `SNESSetFunction()`
5136: Not Collective, but `r` is parallel if `snes` is parallel. Collective if `r` is requested, but has not been created yet.
5138: Input Parameter:
5139: . snes - the `SNES` context
5141: Output Parameters:
5142: + r - the vector that is used to store residuals (or `NULL` if you don't want it)
5143: . f - the function (or `NULL` if you don't want it); for calling sequence see `SNESFunctionFn`
5144: - ctx - the function context (or `NULL` if you don't want it)
5146: Level: advanced
5148: Note:
5149: The vector `r` DOES NOT, in general, contain the current value of the `SNES` nonlinear function
5151: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetSolution()`, `SNESFunctionFn`
5152: @*/
5153: PetscErrorCode SNESGetFunction(SNES snes, Vec *r, SNESFunctionFn **f, void **ctx)
5154: {
5155: DM dm;
5157: PetscFunctionBegin;
5159: if (r) {
5160: if (!snes->vec_func) {
5161: if (snes->vec_rhs) {
5162: PetscCall(VecDuplicate(snes->vec_rhs, &snes->vec_func));
5163: } else if (snes->vec_sol) {
5164: PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_func));
5165: } else if (snes->dm) {
5166: PetscCall(DMCreateGlobalVector(snes->dm, &snes->vec_func));
5167: }
5168: }
5169: *r = snes->vec_func;
5170: }
5171: PetscCall(SNESGetDM(snes, &dm));
5172: PetscCall(DMSNESGetFunction(dm, f, ctx));
5173: PetscFunctionReturn(PETSC_SUCCESS);
5174: }
5176: /*@C
5177: SNESGetNGS - Returns the function and context set with `SNESSetNGS()`
5179: Input Parameter:
5180: . snes - the `SNES` context
5182: Output Parameters:
5183: + f - the function (or `NULL`) see `SNESNGSFn` for calling sequence
5184: - ctx - the function context (or `NULL`)
5186: Level: advanced
5188: .seealso: [](ch_snes), `SNESSetNGS()`, `SNESGetFunction()`, `SNESNGSFn`
5189: @*/
5190: PetscErrorCode SNESGetNGS(SNES snes, SNESNGSFn **f, void **ctx)
5191: {
5192: DM dm;
5194: PetscFunctionBegin;
5196: PetscCall(SNESGetDM(snes, &dm));
5197: PetscCall(DMSNESGetNGS(dm, f, ctx));
5198: PetscFunctionReturn(PETSC_SUCCESS);
5199: }
5201: /*@
5202: SNESSetOptionsPrefix - Sets the prefix used for searching for all
5203: `SNES` options in the database.
5205: Logically Collective
5207: Input Parameters:
5208: + snes - the `SNES` context
5209: - prefix - the prefix to prepend to all option names
5211: Level: advanced
5213: Note:
5214: A hyphen (-) must NOT be given at the beginning of the prefix name.
5215: The first character of all runtime options is AUTOMATICALLY the hyphen.
5217: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESAppendOptionsPrefix()`
5218: @*/
5219: PetscErrorCode SNESSetOptionsPrefix(SNES snes, const char prefix[])
5220: {
5221: PetscFunctionBegin;
5223: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes, prefix));
5224: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5225: if (snes->linesearch) {
5226: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5227: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch, prefix));
5228: }
5229: PetscCall(KSPSetOptionsPrefix(snes->ksp, prefix));
5230: PetscFunctionReturn(PETSC_SUCCESS);
5231: }
5233: /*@
5234: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
5235: `SNES` options in the database.
5237: Logically Collective
5239: Input Parameters:
5240: + snes - the `SNES` context
5241: - prefix - the prefix to prepend to all option names
5243: Level: advanced
5245: Note:
5246: A hyphen (-) must NOT be given at the beginning of the prefix name.
5247: The first character of all runtime options is AUTOMATICALLY the hyphen.
5249: .seealso: [](ch_snes), `SNESGetOptionsPrefix()`, `SNESSetOptionsPrefix()`
5250: @*/
5251: PetscErrorCode SNESAppendOptionsPrefix(SNES snes, const char prefix[])
5252: {
5253: PetscFunctionBegin;
5255: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes, prefix));
5256: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5257: if (snes->linesearch) {
5258: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5259: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch, prefix));
5260: }
5261: PetscCall(KSPAppendOptionsPrefix(snes->ksp, prefix));
5262: PetscFunctionReturn(PETSC_SUCCESS);
5263: }
5265: /*@
5266: SNESGetOptionsPrefix - Gets the prefix used for searching for all
5267: `SNES` options in the database.
5269: Not Collective
5271: Input Parameter:
5272: . snes - the `SNES` context
5274: Output Parameter:
5275: . prefix - pointer to the prefix string used
5277: Level: advanced
5279: .seealso: [](ch_snes), `SNES`, `SNESSetOptionsPrefix()`, `SNESAppendOptionsPrefix()`
5280: @*/
5281: PetscErrorCode SNESGetOptionsPrefix(SNES snes, const char *prefix[])
5282: {
5283: PetscFunctionBegin;
5285: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, prefix));
5286: PetscFunctionReturn(PETSC_SUCCESS);
5287: }
5289: /*@C
5290: SNESRegister - Adds a method to the nonlinear solver package.
5292: Not Collective
5294: Input Parameters:
5295: + sname - name of a new user-defined solver
5296: - function - routine to create method context
5298: Level: advanced
5300: Note:
5301: `SNESRegister()` may be called multiple times to add several user-defined solvers.
5303: Example Usage:
5304: .vb
5305: SNESRegister("my_solver", MySolverCreate);
5306: .ve
5308: Then, your solver can be chosen with the procedural interface via
5309: .vb
5310: SNESSetType(snes, "my_solver")
5311: .ve
5312: or at runtime via the option
5313: .vb
5314: -snes_type my_solver
5315: .ve
5317: .seealso: [](ch_snes), `SNESRegisterAll()`, `SNESRegisterDestroy()`
5318: @*/
5319: PetscErrorCode SNESRegister(const char sname[], PetscErrorCode (*function)(SNES))
5320: {
5321: PetscFunctionBegin;
5322: PetscCall(SNESInitializePackage());
5323: PetscCall(PetscFunctionListAdd(&SNESList, sname, function));
5324: PetscFunctionReturn(PETSC_SUCCESS);
5325: }
5327: PetscErrorCode SNESTestLocalMin(SNES snes)
5328: {
5329: PetscInt N, i, j;
5330: Vec u, uh, fh;
5331: PetscScalar value;
5332: PetscReal norm;
5334: PetscFunctionBegin;
5335: PetscCall(SNESGetSolution(snes, &u));
5336: PetscCall(VecDuplicate(u, &uh));
5337: PetscCall(VecDuplicate(u, &fh));
5339: /* currently only works for sequential */
5340: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "Testing FormFunction() for local min\n"));
5341: PetscCall(VecGetSize(u, &N));
5342: for (i = 0; i < N; i++) {
5343: PetscCall(VecCopy(u, uh));
5344: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "i = %" PetscInt_FMT "\n", i));
5345: for (j = -10; j < 11; j++) {
5346: value = PetscSign(j) * PetscExpReal(PetscAbs(j) - 10.0);
5347: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5348: PetscCall(SNESComputeFunction(snes, uh, fh));
5349: PetscCall(VecNorm(fh, NORM_2, &norm));
5350: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), " j norm %" PetscInt_FMT " %18.16e\n", j, (double)norm));
5351: value = -value;
5352: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5353: }
5354: }
5355: PetscCall(VecDestroy(&uh));
5356: PetscCall(VecDestroy(&fh));
5357: PetscFunctionReturn(PETSC_SUCCESS);
5358: }
5360: /*@
5361: SNESKSPSetUseEW - Sets `SNES` to the use Eisenstat-Walker method for
5362: computing relative tolerance for linear solvers within an inexact
5363: Newton method.
5365: Logically Collective
5367: Input Parameters:
5368: + snes - `SNES` context
5369: - flag - `PETSC_TRUE` or `PETSC_FALSE`
5371: Options Database Keys:
5372: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5373: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
5374: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5375: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5376: . -snes_ksp_ew_gamma <gamma> - Sets gamma
5377: . -snes_ksp_ew_alpha <alpha> - Sets alpha
5378: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5379: - -snes_ksp_ew_threshold <threshold> - Sets threshold
5381: Level: advanced
5383: Note:
5384: The default is to use a constant relative tolerance for
5385: the inner linear solvers. Alternatively, one can use the
5386: Eisenstat-Walker method {cite}`ew96`, where the relative convergence tolerance
5387: is reset at each Newton iteration according progress of the nonlinear
5388: solver.
5390: .seealso: [](ch_snes), `KSP`, `SNES`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5391: @*/
5392: PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)
5393: {
5394: PetscFunctionBegin;
5397: snes->ksp_ewconv = flag;
5398: PetscFunctionReturn(PETSC_SUCCESS);
5399: }
5401: /*@
5402: SNESKSPGetUseEW - Gets if `SNES` is using Eisenstat-Walker method
5403: for computing relative tolerance for linear solvers within an
5404: inexact Newton method.
5406: Not Collective
5408: Input Parameter:
5409: . snes - `SNES` context
5411: Output Parameter:
5412: . flag - `PETSC_TRUE` or `PETSC_FALSE`
5414: Level: advanced
5416: .seealso: [](ch_snes), `SNESKSPSetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5417: @*/
5418: PetscErrorCode SNESKSPGetUseEW(SNES snes, PetscBool *flag)
5419: {
5420: PetscFunctionBegin;
5422: PetscAssertPointer(flag, 2);
5423: *flag = snes->ksp_ewconv;
5424: PetscFunctionReturn(PETSC_SUCCESS);
5425: }
5427: /*@
5428: SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5429: convergence criteria for the linear solvers within an inexact
5430: Newton method.
5432: Logically Collective
5434: Input Parameters:
5435: + snes - `SNES` context
5436: . version - version 1, 2 (default is 2), 3 or 4
5437: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5438: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5439: . gamma - multiplicative factor for version 2 rtol computation
5440: (0 <= gamma2 <= 1)
5441: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5442: . alpha2 - power for safeguard
5443: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5445: Level: advanced
5447: Notes:
5448: Version 3 was contributed by Luis Chacon, June 2006.
5450: Use `PETSC_CURRENT` to retain the default for any of the parameters.
5452: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`
5453: @*/
5454: PetscErrorCode SNESKSPSetParametersEW(SNES snes, PetscInt version, PetscReal rtol_0, PetscReal rtol_max, PetscReal gamma, PetscReal alpha, PetscReal alpha2, PetscReal threshold)
5455: {
5456: SNESKSPEW *kctx;
5458: PetscFunctionBegin;
5460: kctx = (SNESKSPEW *)snes->kspconvctx;
5461: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5470: if (version != PETSC_CURRENT) kctx->version = version;
5471: if (rtol_0 != (PetscReal)PETSC_CURRENT) kctx->rtol_0 = rtol_0;
5472: if (rtol_max != (PetscReal)PETSC_CURRENT) kctx->rtol_max = rtol_max;
5473: if (gamma != (PetscReal)PETSC_CURRENT) kctx->gamma = gamma;
5474: if (alpha != (PetscReal)PETSC_CURRENT) kctx->alpha = alpha;
5475: if (alpha2 != (PetscReal)PETSC_CURRENT) kctx->alpha2 = alpha2;
5476: if (threshold != (PetscReal)PETSC_CURRENT) kctx->threshold = threshold;
5478: 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);
5479: 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);
5480: 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);
5481: 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);
5482: 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);
5483: 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);
5484: PetscFunctionReturn(PETSC_SUCCESS);
5485: }
5487: /*@
5488: SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5489: convergence criteria for the linear solvers within an inexact
5490: Newton method.
5492: Not Collective
5494: Input Parameter:
5495: . snes - `SNES` context
5497: Output Parameters:
5498: + version - version 1, 2 (default is 2), 3 or 4
5499: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5500: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5501: . gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5502: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5503: . alpha2 - power for safeguard
5504: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5506: Level: advanced
5508: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPSetParametersEW()`
5509: @*/
5510: PetscErrorCode SNESKSPGetParametersEW(SNES snes, PetscInt *version, PetscReal *rtol_0, PetscReal *rtol_max, PetscReal *gamma, PetscReal *alpha, PetscReal *alpha2, PetscReal *threshold)
5511: {
5512: SNESKSPEW *kctx;
5514: PetscFunctionBegin;
5516: kctx = (SNESKSPEW *)snes->kspconvctx;
5517: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5518: if (version) *version = kctx->version;
5519: if (rtol_0) *rtol_0 = kctx->rtol_0;
5520: if (rtol_max) *rtol_max = kctx->rtol_max;
5521: if (gamma) *gamma = kctx->gamma;
5522: if (alpha) *alpha = kctx->alpha;
5523: if (alpha2) *alpha2 = kctx->alpha2;
5524: if (threshold) *threshold = kctx->threshold;
5525: PetscFunctionReturn(PETSC_SUCCESS);
5526: }
5528: PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5529: {
5530: SNES snes = (SNES)ctx;
5531: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5532: PetscReal rtol = PETSC_CURRENT, stol;
5534: PetscFunctionBegin;
5535: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5536: if (!snes->iter) {
5537: rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5538: PetscCall(VecNorm(snes->vec_func, NORM_2, &kctx->norm_first));
5539: } else {
5540: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1-4 are supported: %" PetscInt_FMT, kctx->version);
5541: if (kctx->version == 1) {
5542: rtol = PetscAbsReal(snes->norm - kctx->lresid_last) / kctx->norm_last;
5543: stol = PetscPowReal(kctx->rtol_last, kctx->alpha2);
5544: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5545: } else if (kctx->version == 2) {
5546: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5547: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5548: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5549: } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5550: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5551: /* safeguard: avoid sharp decrease of rtol */
5552: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5553: stol = PetscMax(rtol, stol);
5554: rtol = PetscMin(kctx->rtol_0, stol);
5555: /* safeguard: avoid oversolving */
5556: stol = kctx->gamma * (kctx->norm_first * snes->rtol) / snes->norm;
5557: stol = PetscMax(rtol, stol);
5558: rtol = PetscMin(kctx->rtol_0, stol);
5559: } else /* if (kctx->version == 4) */ {
5560: /* H.-B. An et al. Journal of Computational and Applied Mathematics 200 (2007) 47-60 */
5561: PetscReal ared = PetscAbsReal(kctx->norm_last - snes->norm);
5562: PetscReal pred = PetscAbsReal(kctx->norm_last - kctx->lresid_last);
5563: PetscReal rk = ared / pred;
5564: if (rk < kctx->v4_p1) rtol = 1. - 2. * kctx->v4_p1;
5565: else if (rk < kctx->v4_p2) rtol = kctx->rtol_last;
5566: else if (rk < kctx->v4_p3) rtol = kctx->v4_m1 * kctx->rtol_last;
5567: else rtol = kctx->v4_m2 * kctx->rtol_last;
5569: 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;
5570: kctx->rtol_last_2 = kctx->rtol_last;
5571: kctx->rk_last_2 = kctx->rk_last;
5572: kctx->rk_last = rk;
5573: }
5574: }
5575: /* safeguard: avoid rtol greater than rtol_max */
5576: rtol = PetscMin(rtol, kctx->rtol_max);
5577: PetscCall(KSPSetTolerances(ksp, rtol, PETSC_CURRENT, PETSC_CURRENT, PETSC_CURRENT));
5578: PetscCall(PetscInfo(snes, "iter %" PetscInt_FMT ", Eisenstat-Walker (version %" PetscInt_FMT ") KSP rtol=%g\n", snes->iter, kctx->version, (double)rtol));
5579: PetscFunctionReturn(PETSC_SUCCESS);
5580: }
5582: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5583: {
5584: SNES snes = (SNES)ctx;
5585: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5586: PCSide pcside;
5587: Vec lres;
5589: PetscFunctionBegin;
5590: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5591: PetscCall(KSPGetTolerances(ksp, &kctx->rtol_last, NULL, NULL, NULL));
5592: kctx->norm_last = snes->norm;
5593: if (kctx->version == 1 || kctx->version == 4) {
5594: PC pc;
5595: PetscBool getRes;
5597: PetscCall(KSPGetPC(ksp, &pc));
5598: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCNONE, &getRes));
5599: if (!getRes) {
5600: KSPNormType normtype;
5602: PetscCall(KSPGetNormType(ksp, &normtype));
5603: getRes = (PetscBool)(normtype == KSP_NORM_UNPRECONDITIONED);
5604: }
5605: PetscCall(KSPGetPCSide(ksp, &pcside));
5606: if (pcside == PC_RIGHT || getRes) { /* KSP residual is true linear residual */
5607: PetscCall(KSPGetResidualNorm(ksp, &kctx->lresid_last));
5608: } else {
5609: /* KSP residual is preconditioned residual */
5610: /* compute true linear residual norm */
5611: Mat J;
5612: PetscCall(KSPGetOperators(ksp, &J, NULL));
5613: PetscCall(VecDuplicate(b, &lres));
5614: PetscCall(MatMult(J, x, lres));
5615: PetscCall(VecAYPX(lres, -1.0, b));
5616: PetscCall(VecNorm(lres, NORM_2, &kctx->lresid_last));
5617: PetscCall(VecDestroy(&lres));
5618: }
5619: }
5620: PetscFunctionReturn(PETSC_SUCCESS);
5621: }
5623: /*@
5624: SNESGetKSP - Returns the `KSP` context for a `SNES` solver.
5626: Not Collective, but if `snes` is parallel, then `ksp` is parallel
5628: Input Parameter:
5629: . snes - the `SNES` context
5631: Output Parameter:
5632: . ksp - the `KSP` context
5634: Level: beginner
5636: Notes:
5637: The user can then directly manipulate the `KSP` context to set various
5638: options, etc. Likewise, the user can then extract and manipulate the
5639: `PC` contexts as well.
5641: 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.
5643: .seealso: [](ch_snes), `SNES`, `KSP`, `PC`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
5644: @*/
5645: PetscErrorCode SNESGetKSP(SNES snes, KSP *ksp)
5646: {
5647: PetscFunctionBegin;
5649: PetscAssertPointer(ksp, 2);
5651: if (!snes->ksp) {
5652: PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes), &snes->ksp));
5653: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->ksp, (PetscObject)snes, 1));
5655: PetscCall(KSPSetPreSolve(snes->ksp, KSPPreSolve_SNESEW, snes));
5656: PetscCall(KSPSetPostSolve(snes->ksp, KSPPostSolve_SNESEW, snes));
5658: PetscCall(KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes));
5659: PetscCall(PetscObjectSetOptions((PetscObject)snes->ksp, ((PetscObject)snes)->options));
5660: }
5661: *ksp = snes->ksp;
5662: PetscFunctionReturn(PETSC_SUCCESS);
5663: }
5665: #include <petsc/private/dmimpl.h>
5666: /*@
5667: SNESSetDM - Sets the `DM` that may be used by some `SNES` nonlinear solvers or their underlying preconditioners
5669: Logically Collective
5671: Input Parameters:
5672: + snes - the nonlinear solver context
5673: - dm - the `DM`, cannot be `NULL`
5675: Level: intermediate
5677: Note:
5678: A `DM` can only be used for solving one problem at a time because information about the problem is stored on the `DM`,
5679: even when not using interfaces like `DMSNESSetFunction()`. Use `DMClone()` to get a distinct `DM` when solving different
5680: problems using the same function space.
5682: .seealso: [](ch_snes), `DM`, `SNES`, `SNESGetDM()`, `KSPSetDM()`, `KSPGetDM()`
5683: @*/
5684: PetscErrorCode SNESSetDM(SNES snes, DM dm)
5685: {
5686: KSP ksp;
5687: DMSNES sdm;
5689: PetscFunctionBegin;
5692: PetscCall(PetscObjectReference((PetscObject)dm));
5693: if (snes->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
5694: if (snes->dm->dmsnes && !dm->dmsnes) {
5695: PetscCall(DMCopyDMSNES(snes->dm, dm));
5696: PetscCall(DMGetDMSNES(snes->dm, &sdm));
5697: if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5698: }
5699: PetscCall(DMCoarsenHookRemove(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
5700: PetscCall(DMDestroy(&snes->dm));
5701: }
5702: snes->dm = dm;
5703: snes->dmAuto = PETSC_FALSE;
5705: PetscCall(SNESGetKSP(snes, &ksp));
5706: PetscCall(KSPSetDM(ksp, dm));
5707: PetscCall(KSPSetDMActive(ksp, PETSC_FALSE));
5708: if (snes->npc) {
5709: PetscCall(SNESSetDM(snes->npc, snes->dm));
5710: PetscCall(SNESSetNPCSide(snes, snes->npcside));
5711: }
5712: PetscFunctionReturn(PETSC_SUCCESS);
5713: }
5715: /*@
5716: SNESGetDM - Gets the `DM` that may be used by some `SNES` nonlinear solvers/preconditioners
5718: Not Collective but `dm` obtained is parallel on `snes`
5720: Input Parameter:
5721: . snes - the `SNES` context
5723: Output Parameter:
5724: . dm - the `DM`
5726: Level: intermediate
5728: .seealso: [](ch_snes), `DM`, `SNES`, `SNESSetDM()`, `KSPSetDM()`, `KSPGetDM()`
5729: @*/
5730: PetscErrorCode SNESGetDM(SNES snes, DM *dm)
5731: {
5732: PetscFunctionBegin;
5734: if (!snes->dm) {
5735: PetscCall(DMShellCreate(PetscObjectComm((PetscObject)snes), &snes->dm));
5736: snes->dmAuto = PETSC_TRUE;
5737: }
5738: *dm = snes->dm;
5739: PetscFunctionReturn(PETSC_SUCCESS);
5740: }
5742: /*@
5743: SNESSetNPC - Sets the nonlinear preconditioner to be used.
5745: Collective
5747: Input Parameters:
5748: + snes - iterative context obtained from `SNESCreate()`
5749: - npc - the `SNES` nonlinear preconditioner object
5751: Options Database Key:
5752: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5754: Level: developer
5756: Notes:
5757: This is rarely used, rather use `SNESGetNPC()` to retrieve the preconditioner and configure it using the API.
5759: Only some `SNESType` can use a nonlinear preconditioner
5761: .seealso: [](ch_snes), `SNES`, `SNESNGS`, `SNESFAS`, `SNESGetNPC()`, `SNESHasNPC()`
5762: @*/
5763: PetscErrorCode SNESSetNPC(SNES snes, SNES npc)
5764: {
5765: PetscFunctionBegin;
5768: PetscCheckSameComm(snes, 1, npc, 2);
5769: PetscCall(PetscObjectReference((PetscObject)npc));
5770: PetscCall(SNESDestroy(&snes->npc));
5771: snes->npc = npc;
5772: PetscFunctionReturn(PETSC_SUCCESS);
5773: }
5775: /*@
5776: SNESGetNPC - Gets a nonlinear preconditioning solver SNES` to be used to precondition the original nonlinear solver.
5778: Not Collective; but any changes to the obtained the `pc` object must be applied collectively
5780: Input Parameter:
5781: . snes - iterative context obtained from `SNESCreate()`
5783: Output Parameter:
5784: . pc - the `SNES` preconditioner context
5786: Options Database Key:
5787: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5789: Level: advanced
5791: Notes:
5792: If a `SNES` was previously set with `SNESSetNPC()` then that value is returned, otherwise a new `SNES` object is created that will
5793: be used as the nonlinear preconditioner for the current `SNES`.
5795: The (preconditioner) `SNES` returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5796: `SNES`. These may be overwritten if needed.
5798: Use the options database prefixes `-npc_snes`, `-npc_ksp`, etc., to control the configuration of the nonlinear preconditioner
5800: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESHasNPC()`, `SNES`, `SNESCreate()`
5801: @*/
5802: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5803: {
5804: const char *optionsprefix;
5806: PetscFunctionBegin;
5808: PetscAssertPointer(pc, 2);
5809: if (!snes->npc) {
5810: void *ctx;
5812: PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &snes->npc));
5813: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->npc, (PetscObject)snes, 1));
5814: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5815: PetscCall(SNESSetOptionsPrefix(snes->npc, optionsprefix));
5816: PetscCall(SNESAppendOptionsPrefix(snes->npc, "npc_"));
5817: if (snes->ops->usercompute) {
5818: PetscCall(SNESSetComputeApplicationContext(snes, snes->ops->usercompute, snes->ops->ctxdestroy));
5819: } else {
5820: PetscCall(SNESGetApplicationContext(snes, &ctx));
5821: PetscCall(SNESSetApplicationContext(snes->npc, ctx));
5822: }
5823: PetscCall(SNESSetCountersReset(snes->npc, PETSC_FALSE));
5824: }
5825: *pc = snes->npc;
5826: PetscFunctionReturn(PETSC_SUCCESS);
5827: }
5829: /*@
5830: SNESHasNPC - Returns whether a nonlinear preconditioner is associated with the given `SNES`
5832: Not Collective
5834: Input Parameter:
5835: . snes - iterative context obtained from `SNESCreate()`
5837: Output Parameter:
5838: . has_npc - whether the `SNES` has a nonlinear preconditioner or not
5840: Level: developer
5842: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESGetNPC()`
5843: @*/
5844: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5845: {
5846: PetscFunctionBegin;
5848: PetscAssertPointer(has_npc, 2);
5849: *has_npc = snes->npc ? PETSC_TRUE : PETSC_FALSE;
5850: PetscFunctionReturn(PETSC_SUCCESS);
5851: }
5853: /*@
5854: SNESSetNPCSide - Sets the nonlinear preconditioning side used by the nonlinear preconditioner inside `SNES`.
5856: Logically Collective
5858: Input Parameter:
5859: . snes - iterative context obtained from `SNESCreate()`
5861: Output Parameter:
5862: . side - the preconditioning side, where side is one of
5863: .vb
5864: PC_LEFT - left preconditioning
5865: PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5866: .ve
5868: Options Database Key:
5869: . -snes_npc_side <right,left> - nonlinear preconditioner side
5871: Level: intermediate
5873: Note:
5874: `SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.
5876: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESNRICHARDSON`, `SNESNCG`, `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5877: @*/
5878: PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
5879: {
5880: PetscFunctionBegin;
5883: if (side == PC_SIDE_DEFAULT) side = PC_RIGHT;
5884: PetscCheck((side == PC_LEFT) || (side == PC_RIGHT), PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Only PC_LEFT and PC_RIGHT are supported");
5885: snes->npcside = side;
5886: PetscFunctionReturn(PETSC_SUCCESS);
5887: }
5889: /*@
5890: SNESGetNPCSide - Gets the preconditioning side used by the nonlinear preconditioner inside `SNES`.
5892: Not Collective
5894: Input Parameter:
5895: . snes - iterative context obtained from `SNESCreate()`
5897: Output Parameter:
5898: . side - the preconditioning side, where side is one of
5899: .vb
5900: `PC_LEFT` - left preconditioning
5901: `PC_RIGHT` - right preconditioning (default for most nonlinear solvers)
5902: .ve
5904: Level: intermediate
5906: .seealso: [](ch_snes), `SNES`, `SNESGetNPC()`, `SNESSetNPCSide()`, `KSPGetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5907: @*/
5908: PetscErrorCode SNESGetNPCSide(SNES snes, PCSide *side)
5909: {
5910: PetscFunctionBegin;
5912: PetscAssertPointer(side, 2);
5913: *side = snes->npcside;
5914: PetscFunctionReturn(PETSC_SUCCESS);
5915: }
5917: /*@
5918: SNESSetLineSearch - Sets the `SNESLineSearch` to be used for a given `SNES`
5920: Collective
5922: Input Parameters:
5923: + snes - iterative context obtained from `SNESCreate()`
5924: - linesearch - the linesearch object
5926: Level: developer
5928: Note:
5929: This is almost never used, rather one uses `SNESGetLineSearch()` to retrieve the line search and set options on it
5930: to configure it using the API).
5932: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`
5933: @*/
5934: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5935: {
5936: PetscFunctionBegin;
5939: PetscCheckSameComm(snes, 1, linesearch, 2);
5940: PetscCall(PetscObjectReference((PetscObject)linesearch));
5941: PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5943: snes->linesearch = linesearch;
5944: PetscFunctionReturn(PETSC_SUCCESS);
5945: }
5947: /*@
5948: SNESGetLineSearch - Returns the line search associated with the `SNES`.
5950: Not Collective
5952: Input Parameter:
5953: . snes - iterative context obtained from `SNESCreate()`
5955: Output Parameter:
5956: . linesearch - linesearch context
5958: Level: beginner
5960: Notes:
5961: It creates a default line search instance which can be configured as needed in case it has not been already set with `SNESSetLineSearch()`.
5963: You can also use the options database keys `-snes_linesearch_*` to configure the line search. See `SNESLineSearchSetFromOptions()` for the possible options.
5965: .seealso: [](ch_snes), `SNESLineSearch`, `SNESSetLineSearch()`, `SNESLineSearchCreate()`, `SNESLineSearchSetFromOptions()`
5966: @*/
5967: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5968: {
5969: const char *optionsprefix;
5971: PetscFunctionBegin;
5973: PetscAssertPointer(linesearch, 2);
5974: if (!snes->linesearch) {
5975: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5976: PetscCall(SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch));
5977: PetscCall(SNESLineSearchSetSNES(snes->linesearch, snes));
5978: PetscCall(SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix));
5979: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->linesearch, (PetscObject)snes, 1));
5980: }
5981: *linesearch = snes->linesearch;
5982: PetscFunctionReturn(PETSC_SUCCESS);
5983: }