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_NPCSolve, SNES_ObjectiveEval;
15: /*@
16: SNESSetErrorIfNotConverged - Causes `SNESSolve()` to generate an error immediately if the solver has not converged.
18: Logically Collective
20: Input Parameters:
21: + snes - iterative context obtained from `SNESCreate()`
22: - flg - `PETSC_TRUE` indicates you want the error generated
24: Options Database Key:
25: . -snes_error_if_not_converged <true,false> - cause an immediate error condition and stop the program if the solver does not converge
27: Level: intermediate
29: Note:
30: Normally PETSc continues if a solver fails to converge, you can call `SNESGetConvergedReason()` after a `SNESSolve()`
31: to determine if it has converged. Otherwise the solution may be inaccurate or wrong
33: .seealso: [](ch_snes), `SNES`, `SNESGetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
34: @*/
35: PetscErrorCode SNESSetErrorIfNotConverged(SNES snes, PetscBool flg)
36: {
37: PetscFunctionBegin;
40: snes->errorifnotconverged = flg;
41: PetscFunctionReturn(PETSC_SUCCESS);
42: }
44: /*@
45: SNESGetErrorIfNotConverged - Indicates if `SNESSolve()` will generate an error if the solver does not converge?
47: Not Collective
49: Input Parameter:
50: . snes - iterative context obtained from `SNESCreate()`
52: Output Parameter:
53: . flag - `PETSC_TRUE` if it will generate an error, else `PETSC_FALSE`
55: Level: intermediate
57: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetErrorIfNotConverged()`, `KSPGetErrorIfNotConverged()`, `KSPSetErrorIfNotConverged()`
58: @*/
59: PetscErrorCode SNESGetErrorIfNotConverged(SNES snes, PetscBool *flag)
60: {
61: PetscFunctionBegin;
63: PetscAssertPointer(flag, 2);
64: *flag = snes->errorifnotconverged;
65: PetscFunctionReturn(PETSC_SUCCESS);
66: }
68: /*@
69: SNESSetAlwaysComputesFinalResidual - tells the `SNES` to always compute the residual (nonlinear function value) at the final solution
71: Logically Collective
73: Input Parameters:
74: + snes - the shell `SNES`
75: - flg - `PETSC_TRUE` to always compute the residual
77: Level: advanced
79: Note:
80: Some solvers (such as smoothers in a `SNESFAS`) do not need the residual computed at the final solution so skip computing it
81: to save time.
83: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSolve()`, `SNESGetAlwaysComputesFinalResidual()`
84: @*/
85: PetscErrorCode SNESSetAlwaysComputesFinalResidual(SNES snes, PetscBool flg)
86: {
87: PetscFunctionBegin;
89: snes->alwayscomputesfinalresidual = flg;
90: PetscFunctionReturn(PETSC_SUCCESS);
91: }
93: /*@
94: SNESGetAlwaysComputesFinalResidual - checks if the `SNES` always computes the residual at the final solution
96: Logically Collective
98: Input Parameter:
99: . snes - the `SNES` context
101: Output Parameter:
102: . flg - `PETSC_TRUE` if the residual is computed
104: Level: advanced
106: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSolve()`, `SNESSetAlwaysComputesFinalResidual()`
107: @*/
108: PetscErrorCode SNESGetAlwaysComputesFinalResidual(SNES snes, PetscBool *flg)
109: {
110: PetscFunctionBegin;
112: *flg = snes->alwayscomputesfinalresidual;
113: PetscFunctionReturn(PETSC_SUCCESS);
114: }
116: /*@
117: SNESSetFunctionDomainError - tells `SNES` that the input vector, a proposed new solution, to your function you provided to `SNESSetFunction()` is not
118: in the functions domain. For example, a step with negative pressure.
120: Logically Collective
122: Input Parameter:
123: . snes - the `SNES` context
125: Level: advanced
127: Notes:
128: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
130: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
132: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
133: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
135: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetJacobianDomainError()`, `SNESVISetVariableBounds()`,
136: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`
137: @*/
138: PetscErrorCode SNESSetFunctionDomainError(SNES snes)
139: {
140: PetscFunctionBegin;
142: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates input vector is not in the function domain");
143: snes->domainerror = PETSC_TRUE;
144: PetscFunctionReturn(PETSC_SUCCESS);
145: }
147: /*@
148: SNESSetJacobianDomainError - tells `SNES` that the function you provided to `SNESSetJacobian()` at the proposed step. For example there is a negative element transformation.
150: Logically Collective
152: Input Parameter:
153: . snes - the `SNES` context
155: Level: advanced
157: Notes:
158: If this is called the `SNESSolve()` stops iterating and returns with a `SNESConvergedReason` of `SNES_DIVERGED_FUNCTION_DOMAIN`
160: You should always call `SNESGetConvergedReason()` after each `SNESSolve()` and verify if the iteration converged (positive result) or diverged (negative result).
162: You can direct `SNES` to avoid certain steps by using `SNESVISetVariableBounds()`, `SNESVISetComputeVariableBounds()` or
163: `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`
165: .seealso: [](ch_snes), `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESVISetVariableBounds()`,
166: `SNESVISetComputeVariableBounds()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESConvergedReason`, `SNESGetConvergedReason()`
167: @*/
168: PetscErrorCode SNESSetJacobianDomainError(SNES snes)
169: {
170: PetscFunctionBegin;
172: PetscCheck(!snes->errorifnotconverged, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "User code indicates computeJacobian does not make sense");
173: snes->jacobiandomainerror = PETSC_TRUE;
174: PetscFunctionReturn(PETSC_SUCCESS);
175: }
177: /*@
178: SNESSetCheckJacobianDomainError - tells `SNESSolve()` whether to check if the user called `SNESSetJacobianDomainError()` Jacobian domain error after
179: each Jacobian evaluation. By default, it checks for the Jacobian domain error in the debug mode, and does not check it in the optimized mode.
181: Logically Collective
183: Input Parameters:
184: + snes - the `SNES` context
185: - flg - indicates if or not to check Jacobian domain error after each Jacobian evaluation
187: Level: advanced
189: Note:
190: Checks require one extra parallel synchronization for each Jacobian evaluation
192: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESGetCheckJacobianDomainError()`
193: @*/
194: PetscErrorCode SNESSetCheckJacobianDomainError(SNES snes, PetscBool flg)
195: {
196: PetscFunctionBegin;
198: snes->checkjacdomainerror = flg;
199: PetscFunctionReturn(PETSC_SUCCESS);
200: }
202: /*@
203: SNESGetCheckJacobianDomainError - Get an indicator whether or not `SNES` is checking Jacobian domain errors after each Jacobian evaluation.
205: Logically Collective
207: Input Parameter:
208: . snes - the `SNES` context
210: Output Parameter:
211: . flg - `PETSC_FALSE` indicates that it is not checking Jacobian domain errors after each Jacobian evaluation
213: Level: advanced
215: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSetFunction()`, `SNESFunctionFn`, `SNESSetFunctionDomainError()`, `SNESSetCheckJacobianDomainError()`
216: @*/
217: PetscErrorCode SNESGetCheckJacobianDomainError(SNES snes, PetscBool *flg)
218: {
219: PetscFunctionBegin;
221: PetscAssertPointer(flg, 2);
222: *flg = snes->checkjacdomainerror;
223: PetscFunctionReturn(PETSC_SUCCESS);
224: }
226: /*@
227: SNESGetFunctionDomainError - Gets the status of the domain error after a call to `SNESComputeFunction()`
229: Logically Collective
231: Input Parameter:
232: . snes - the `SNES` context
234: Output Parameter:
235: . domainerror - Set to `PETSC_TRUE` if there's a domain error; `PETSC_FALSE` otherwise.
237: Level: developer
239: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`
240: @*/
241: PetscErrorCode SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
242: {
243: PetscFunctionBegin;
245: PetscAssertPointer(domainerror, 2);
246: *domainerror = snes->domainerror;
247: PetscFunctionReturn(PETSC_SUCCESS);
248: }
250: /*@
251: SNESGetJacobianDomainError - Gets the status of the Jacobian domain error after a call to `SNESComputeJacobian()`
253: Logically Collective
255: Input Parameter:
256: . snes - the `SNES` context
258: Output Parameter:
259: . domainerror - Set to `PETSC_TRUE` if there's a Jacobian domain error; `PETSC_FALSE` otherwise.
261: Level: advanced
263: .seealso: [](ch_snes), `SNES`, `SNESSetFunctionDomainError()`, `SNESComputeFunction()`, `SNESGetFunctionDomainError()`
264: @*/
265: PetscErrorCode SNESGetJacobianDomainError(SNES snes, PetscBool *domainerror)
266: {
267: PetscFunctionBegin;
269: PetscAssertPointer(domainerror, 2);
270: *domainerror = snes->jacobiandomainerror;
271: PetscFunctionReturn(PETSC_SUCCESS);
272: }
274: /*@C
275: SNESLoad - Loads a `SNES` that has been stored in `PETSCVIEWERBINARY` with `SNESView()`.
277: Collective
279: Input Parameters:
280: + snes - the newly loaded `SNES`, this needs to have been created with `SNESCreate()` or
281: some related function before a call to `SNESLoad()`.
282: - viewer - binary file viewer, obtained from `PetscViewerBinaryOpen()`
284: Level: intermediate
286: Note:
287: The `SNESType` is determined by the data in the file, any type set into the `SNES` before this call is ignored.
289: .seealso: [](ch_snes), `SNES`, `PetscViewer`, `SNESCreate()`, `SNESType`, `PetscViewerBinaryOpen()`, `SNESView()`, `MatLoad()`, `VecLoad()`
290: @*/
291: PetscErrorCode SNESLoad(SNES snes, PetscViewer viewer)
292: {
293: PetscBool isbinary;
294: PetscInt classid;
295: char type[256];
296: KSP ksp;
297: DM dm;
298: DMSNES dmsnes;
300: PetscFunctionBegin;
303: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
304: PetscCheck(isbinary, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Invalid viewer; open viewer with PetscViewerBinaryOpen()");
306: PetscCall(PetscViewerBinaryRead(viewer, &classid, 1, NULL, PETSC_INT));
307: PetscCheck(classid == SNES_FILE_CLASSID, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Not SNES next in file");
308: PetscCall(PetscViewerBinaryRead(viewer, type, 256, NULL, PETSC_CHAR));
309: PetscCall(SNESSetType(snes, type));
310: PetscTryTypeMethod(snes, load, viewer);
311: PetscCall(SNESGetDM(snes, &dm));
312: PetscCall(DMGetDMSNES(dm, &dmsnes));
313: PetscCall(DMSNESLoad(dmsnes, viewer));
314: PetscCall(SNESGetKSP(snes, &ksp));
315: PetscCall(KSPLoad(ksp, viewer));
316: PetscFunctionReturn(PETSC_SUCCESS);
317: }
319: #include <petscdraw.h>
320: #if defined(PETSC_HAVE_SAWS)
321: #include <petscviewersaws.h>
322: #endif
324: /*@C
325: SNESViewFromOptions - View a `SNES` based on values in the options database
327: Collective
329: Input Parameters:
330: + A - the `SNES` context
331: . obj - Optional object that provides the options prefix for the checks
332: - name - command line option
334: Level: intermediate
336: .seealso: [](ch_snes), `SNES`, `SNESView`, `PetscObjectViewFromOptions()`, `SNESCreate()`
337: @*/
338: PetscErrorCode SNESViewFromOptions(SNES A, PetscObject obj, const char name[])
339: {
340: PetscFunctionBegin;
342: PetscCall(PetscObjectViewFromOptions((PetscObject)A, obj, name));
343: PetscFunctionReturn(PETSC_SUCCESS);
344: }
346: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES, Vec, Mat, Mat, void *);
348: /*@C
349: SNESView - Prints or visualizes the `SNES` data structure.
351: Collective
353: Input Parameters:
354: + snes - the `SNES` context
355: - viewer - the `PetscViewer`
357: Options Database Key:
358: . -snes_view - Calls `SNESView()` at end of `SNESSolve()`
360: Level: beginner
362: Notes:
363: The available visualization contexts include
364: + `PETSC_VIEWER_STDOUT_SELF` - standard output (default)
365: - `PETSC_VIEWER_STDOUT_WORLD` - synchronized standard
366: output where only the first processor opens
367: the file. All other processors send their
368: data to the first processor to print.
370: The available formats include
371: + `PETSC_VIEWER_DEFAULT` - standard output (default)
372: - `PETSC_VIEWER_ASCII_INFO_DETAIL` - more verbose output for `SNESNASM`
374: The user can open an alternative visualization context with
375: `PetscViewerASCIIOpen()` - output to a specified file.
377: In the debugger you can do "call `SNESView`(snes,0)" to display the `SNES` solver. (The same holds for any PETSc object viewer).
379: .seealso: [](ch_snes), `SNES`, `SNESLoad()`, `SNESCreate()`, `PetscViewerASCIIOpen()`
380: @*/
381: PetscErrorCode SNESView(SNES snes, PetscViewer viewer)
382: {
383: SNESKSPEW *kctx;
384: KSP ksp;
385: SNESLineSearch linesearch;
386: PetscBool iascii, isstring, isbinary, isdraw;
387: DMSNES dmsnes;
388: #if defined(PETSC_HAVE_SAWS)
389: PetscBool issaws;
390: #endif
392: PetscFunctionBegin;
394: if (!viewer) PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &viewer));
396: PetscCheckSameComm(snes, 1, viewer, 2);
398: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
399: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSTRING, &isstring));
400: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
401: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
402: #if defined(PETSC_HAVE_SAWS)
403: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERSAWS, &issaws));
404: #endif
405: if (iascii) {
406: SNESNormSchedule normschedule;
407: DM dm;
408: SNESJacobianFn *cJ;
409: void *ctx;
410: const char *pre = "";
412: PetscCall(PetscObjectPrintClassNamePrefixType((PetscObject)snes, viewer));
413: if (!snes->setupcalled) PetscCall(PetscViewerASCIIPrintf(viewer, " SNES has not been set up so information may be incomplete\n"));
414: if (snes->ops->view) {
415: PetscCall(PetscViewerASCIIPushTab(viewer));
416: PetscUseTypeMethod(snes, view, viewer);
417: PetscCall(PetscViewerASCIIPopTab(viewer));
418: }
419: PetscCall(PetscViewerASCIIPrintf(viewer, " maximum iterations=%" PetscInt_FMT ", maximum function evaluations=%" PetscInt_FMT "\n", snes->max_its, snes->max_funcs));
420: PetscCall(PetscViewerASCIIPrintf(viewer, " tolerances: relative=%g, absolute=%g, solution=%g\n", (double)snes->rtol, (double)snes->abstol, (double)snes->stol));
421: if (snes->usesksp) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of linear solver iterations=%" PetscInt_FMT "\n", snes->linear_its));
422: PetscCall(PetscViewerASCIIPrintf(viewer, " total number of function evaluations=%" PetscInt_FMT "\n", snes->nfuncs));
423: PetscCall(SNESGetNormSchedule(snes, &normschedule));
424: if (normschedule > 0) PetscCall(PetscViewerASCIIPrintf(viewer, " norm schedule %s\n", SNESNormSchedules[normschedule]));
425: if (snes->gridsequence) PetscCall(PetscViewerASCIIPrintf(viewer, " total number of grid sequence refinements=%" PetscInt_FMT "\n", snes->gridsequence));
426: if (snes->ksp_ewconv) {
427: kctx = (SNESKSPEW *)snes->kspconvctx;
428: if (kctx) {
429: PetscCall(PetscViewerASCIIPrintf(viewer, " Eisenstat-Walker computation of KSP relative tolerance (version %" PetscInt_FMT ")\n", kctx->version));
430: PetscCall(PetscViewerASCIIPrintf(viewer, " rtol_0=%g, rtol_max=%g, threshold=%g\n", (double)kctx->rtol_0, (double)kctx->rtol_max, (double)kctx->threshold));
431: PetscCall(PetscViewerASCIIPrintf(viewer, " gamma=%g, alpha=%g, alpha2=%g\n", (double)kctx->gamma, (double)kctx->alpha, (double)kctx->alpha2));
432: }
433: }
434: if (snes->lagpreconditioner == -1) {
435: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is never rebuilt\n"));
436: } else if (snes->lagpreconditioner > 1) {
437: PetscCall(PetscViewerASCIIPrintf(viewer, " Preconditioned is rebuilt every %" PetscInt_FMT " new Jacobians\n", snes->lagpreconditioner));
438: }
439: if (snes->lagjacobian == -1) {
440: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is never rebuilt\n"));
441: } else if (snes->lagjacobian > 1) {
442: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is rebuilt every %" PetscInt_FMT " SNES iterations\n", snes->lagjacobian));
443: }
444: PetscCall(SNESGetDM(snes, &dm));
445: PetscCall(DMSNESGetJacobian(dm, &cJ, &ctx));
446: if (snes->mf_operator) {
447: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing\n"));
448: pre = "Preconditioning ";
449: }
450: if (cJ == SNESComputeJacobianDefault) {
451: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences one column at a time\n", pre));
452: } else if (cJ == SNESComputeJacobianDefaultColor) {
453: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using finite differences with coloring\n", pre));
454: /* it slightly breaks data encapsulation for access the DMDA information directly */
455: } else if (cJ == SNESComputeJacobian_DMDA) {
456: MatFDColoring fdcoloring;
457: PetscCall(PetscObjectQuery((PetscObject)dm, "DMDASNES_FDCOLORING", (PetscObject *)&fdcoloring));
458: if (fdcoloring) {
459: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using colored finite differences on a DMDA\n", pre));
460: } else {
461: PetscCall(PetscViewerASCIIPrintf(viewer, " %sJacobian is built using a DMDA local Jacobian\n", pre));
462: }
463: } else if (snes->mf && !snes->mf_operator) {
464: PetscCall(PetscViewerASCIIPrintf(viewer, " Jacobian is applied matrix-free with differencing, no explicit Jacobian\n"));
465: }
466: } else if (isstring) {
467: const char *type;
468: PetscCall(SNESGetType(snes, &type));
469: PetscCall(PetscViewerStringSPrintf(viewer, " SNESType: %-7.7s", type));
470: PetscTryTypeMethod(snes, view, viewer);
471: } else if (isbinary) {
472: PetscInt classid = SNES_FILE_CLASSID;
473: MPI_Comm comm;
474: PetscMPIInt rank;
475: char type[256];
477: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
478: PetscCallMPI(MPI_Comm_rank(comm, &rank));
479: if (rank == 0) {
480: PetscCall(PetscViewerBinaryWrite(viewer, &classid, 1, PETSC_INT));
481: PetscCall(PetscStrncpy(type, ((PetscObject)snes)->type_name, sizeof(type)));
482: PetscCall(PetscViewerBinaryWrite(viewer, type, sizeof(type), PETSC_CHAR));
483: }
484: PetscTryTypeMethod(snes, view, viewer);
485: } else if (isdraw) {
486: PetscDraw draw;
487: char str[36];
488: PetscReal x, y, bottom, h;
490: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
491: PetscCall(PetscDrawGetCurrentPoint(draw, &x, &y));
492: PetscCall(PetscStrncpy(str, "SNES: ", sizeof(str)));
493: PetscCall(PetscStrlcat(str, ((PetscObject)snes)->type_name, sizeof(str)));
494: PetscCall(PetscDrawStringBoxed(draw, x, y, PETSC_DRAW_BLUE, PETSC_DRAW_BLACK, str, NULL, &h));
495: bottom = y - h;
496: PetscCall(PetscDrawPushCurrentPoint(draw, x, bottom));
497: PetscTryTypeMethod(snes, view, viewer);
498: #if defined(PETSC_HAVE_SAWS)
499: } else if (issaws) {
500: PetscMPIInt rank;
501: const char *name;
503: PetscCall(PetscObjectGetName((PetscObject)snes, &name));
504: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
505: if (!((PetscObject)snes)->amsmem && rank == 0) {
506: char dir[1024];
508: PetscCall(PetscObjectViewSAWs((PetscObject)snes, viewer));
509: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/its", name));
510: PetscCallSAWs(SAWs_Register, (dir, &snes->iter, 1, SAWs_READ, SAWs_INT));
511: if (!snes->conv_hist) PetscCall(SNESSetConvergenceHistory(snes, NULL, NULL, PETSC_DECIDE, PETSC_TRUE));
512: PetscCall(PetscSNPrintf(dir, 1024, "/PETSc/Objects/%s/conv_hist", name));
513: PetscCallSAWs(SAWs_Register, (dir, snes->conv_hist, 10, SAWs_READ, SAWs_DOUBLE));
514: }
515: #endif
516: }
517: if (snes->linesearch) {
518: PetscCall(SNESGetLineSearch(snes, &linesearch));
519: PetscCall(PetscViewerASCIIPushTab(viewer));
520: PetscCall(SNESLineSearchView(linesearch, viewer));
521: PetscCall(PetscViewerASCIIPopTab(viewer));
522: }
523: if (snes->npc && snes->usesnpc) {
524: PetscCall(PetscViewerASCIIPushTab(viewer));
525: PetscCall(SNESView(snes->npc, viewer));
526: PetscCall(PetscViewerASCIIPopTab(viewer));
527: }
528: PetscCall(PetscViewerASCIIPushTab(viewer));
529: PetscCall(DMGetDMSNES(snes->dm, &dmsnes));
530: PetscCall(DMSNESView(dmsnes, viewer));
531: PetscCall(PetscViewerASCIIPopTab(viewer));
532: if (snes->usesksp) {
533: PetscCall(SNESGetKSP(snes, &ksp));
534: PetscCall(PetscViewerASCIIPushTab(viewer));
535: PetscCall(KSPView(ksp, viewer));
536: PetscCall(PetscViewerASCIIPopTab(viewer));
537: }
538: if (isdraw) {
539: PetscDraw draw;
540: PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
541: PetscCall(PetscDrawPopCurrentPoint(draw));
542: }
543: PetscFunctionReturn(PETSC_SUCCESS);
544: }
546: /*
547: We retain a list of functions that also take SNES command
548: line options. These are called at the end SNESSetFromOptions()
549: */
550: #define MAXSETFROMOPTIONS 5
551: static PetscInt numberofsetfromoptions;
552: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);
554: /*@C
555: SNESAddOptionsChecker - Adds an additional function to check for `SNES` options.
557: Not Collective
559: Input Parameter:
560: . snescheck - function that checks for options
562: Calling sequence of `snescheck`:
563: . snes - the `SNES` object for which it is checking options
565: Level: developer
567: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`
568: @*/
569: PetscErrorCode SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES snes))
570: {
571: PetscFunctionBegin;
572: PetscCheck(numberofsetfromoptions < MAXSETFROMOPTIONS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %d allowed", MAXSETFROMOPTIONS);
573: othersetfromoptions[numberofsetfromoptions++] = snescheck;
574: PetscFunctionReturn(PETSC_SUCCESS);
575: }
577: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
578: {
579: Mat J;
580: MatNullSpace nullsp;
582: PetscFunctionBegin;
585: if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
586: Mat A = snes->jacobian, B = snes->jacobian_pre;
587: PetscCall(MatCreateVecs(A ? A : B, NULL, &snes->vec_func));
588: }
590: PetscCheck(version == 1 || version == 2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator routines, only version 1 and 2");
591: if (version == 1) {
592: PetscCall(MatCreateSNESMF(snes, &J));
593: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
594: PetscCall(MatSetFromOptions(J));
595: /* TODO: the version 2 code should be merged into the MatCreateSNESMF() and MatCreateMFFD() infrastructure and then removed */
596: } else /* if (version == 2) */ {
597: PetscCheck(snes->vec_func, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "SNESSetFunction() must be called first");
598: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
599: PetscCall(MatCreateSNESMFMore(snes, snes->vec_func, &J));
600: #else
601: SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "matrix-free operator routines (version 2)");
602: #endif
603: }
605: /* attach any user provided null space that was on Amat to the newly created matrix-free matrix */
606: if (snes->jacobian) {
607: PetscCall(MatGetNullSpace(snes->jacobian, &nullsp));
608: if (nullsp) PetscCall(MatSetNullSpace(J, nullsp));
609: }
611: PetscCall(PetscInfo(snes, "Setting default matrix-free operator routines (version %" PetscInt_FMT ")\n", version));
612: if (hasOperator) {
613: /* This version replaces the user provided Jacobian matrix with a
614: matrix-free version but still employs the user-provided preconditioner matrix. */
615: PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
616: } else {
617: /* This version replaces both the user-provided Jacobian and the user-
618: provided preconditioner Jacobian with the default matrix-free version. */
619: if (snes->npcside == PC_LEFT && snes->npc) {
620: if (!snes->jacobian) PetscCall(SNESSetJacobian(snes, J, NULL, NULL, NULL));
621: } else {
622: KSP ksp;
623: PC pc;
624: PetscBool match;
626: PetscCall(SNESSetJacobian(snes, J, J, MatMFFDComputeJacobian, NULL));
627: /* Force no preconditioner */
628: PetscCall(SNESGetKSP(snes, &ksp));
629: PetscCall(KSPGetPC(ksp, &pc));
630: PetscCall(PetscObjectTypeCompareAny((PetscObject)pc, &match, PCSHELL, PCH2OPUS, ""));
631: if (!match) {
632: PetscCall(PetscInfo(snes, "Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n"));
633: PetscCall(PCSetType(pc, PCNONE));
634: }
635: }
636: }
637: PetscCall(MatDestroy(&J));
638: PetscFunctionReturn(PETSC_SUCCESS);
639: }
641: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine, Mat Restrict, Vec Rscale, Mat Inject, DM dmcoarse, void *ctx)
642: {
643: SNES snes = (SNES)ctx;
644: Vec Xfine, Xfine_named = NULL, Xcoarse;
646: PetscFunctionBegin;
647: if (PetscLogPrintInfo) {
648: PetscInt finelevel, coarselevel, fineclevel, coarseclevel;
649: PetscCall(DMGetRefineLevel(dmfine, &finelevel));
650: PetscCall(DMGetCoarsenLevel(dmfine, &fineclevel));
651: PetscCall(DMGetRefineLevel(dmcoarse, &coarselevel));
652: PetscCall(DMGetCoarsenLevel(dmcoarse, &coarseclevel));
653: PetscCall(PetscInfo(dmfine, "Restricting SNES solution vector from level %" PetscInt_FMT "-%" PetscInt_FMT " to level %" PetscInt_FMT "-%" PetscInt_FMT "\n", finelevel, fineclevel, coarselevel, coarseclevel));
654: }
655: if (dmfine == snes->dm) Xfine = snes->vec_sol;
656: else {
657: PetscCall(DMGetNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
658: Xfine = Xfine_named;
659: }
660: PetscCall(DMGetNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
661: if (Inject) {
662: PetscCall(MatRestrict(Inject, Xfine, Xcoarse));
663: } else {
664: PetscCall(MatRestrict(Restrict, Xfine, Xcoarse));
665: PetscCall(VecPointwiseMult(Xcoarse, Xcoarse, Rscale));
666: }
667: PetscCall(DMRestoreNamedGlobalVector(dmcoarse, "SNESVecSol", &Xcoarse));
668: if (Xfine_named) PetscCall(DMRestoreNamedGlobalVector(dmfine, "SNESVecSol", &Xfine_named));
669: PetscFunctionReturn(PETSC_SUCCESS);
670: }
672: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm, DM dmc, void *ctx)
673: {
674: PetscFunctionBegin;
675: PetscCall(DMCoarsenHookAdd(dmc, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, ctx));
676: PetscFunctionReturn(PETSC_SUCCESS);
677: }
679: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
680: * safely call SNESGetDM() in their residual evaluation routine. */
681: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp, Mat A, Mat B, void *ctx)
682: {
683: SNES snes = (SNES)ctx;
684: DMSNES sdm;
685: Vec X, Xnamed = NULL;
686: DM dmsave;
687: void *ctxsave;
688: SNESJacobianFn *jac = NULL;
690: PetscFunctionBegin;
691: dmsave = snes->dm;
692: PetscCall(KSPGetDM(ksp, &snes->dm));
693: if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
694: else {
695: PetscBool has;
697: /* We are on a coarser level, this vec was initialized using a DM restrict hook */
698: PetscCall(DMHasNamedGlobalVector(snes->dm, "SNESVecSol", &has));
699: PetscCheck(has, PetscObjectComm((PetscObject)snes->dm), PETSC_ERR_PLIB, "Missing SNESVecSol");
700: PetscCall(DMGetNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
701: X = Xnamed;
702: PetscCall(SNESGetJacobian(snes, NULL, NULL, &jac, &ctxsave));
703: /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
704: if (jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, SNESComputeJacobianDefaultColor, NULL));
705: }
707: /* Compute the operators */
708: PetscCall(DMGetDMSNES(snes->dm, &sdm));
709: if (Xnamed && sdm->ops->computefunction) {
710: /* The SNES contract with the user is that ComputeFunction is always called before ComputeJacobian.
711: We make sure of this here. Disable affine shift since it is for the finest level */
712: Vec F, saverhs = snes->vec_rhs;
714: snes->vec_rhs = NULL;
715: PetscCall(DMGetGlobalVector(snes->dm, &F));
716: PetscCall(SNESComputeFunction(snes, X, F));
717: PetscCall(DMRestoreGlobalVector(snes->dm, &F));
718: snes->vec_rhs = saverhs;
719: snes->nfuncs--; /* Do not log coarser level evaluations */
720: }
721: /* Make sure KSP DM has the Jacobian computation routine */
722: if (!sdm->ops->computejacobian) PetscCall(DMCopyDMSNES(dmsave, snes->dm));
723: PetscCall(SNESComputeJacobian(snes, X, A, B));
725: /* Put the previous context back */
726: if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) PetscCall(SNESSetJacobian(snes, NULL, NULL, jac, ctxsave));
728: if (Xnamed) PetscCall(DMRestoreNamedGlobalVector(snes->dm, "SNESVecSol", &Xnamed));
729: snes->dm = dmsave;
730: PetscFunctionReturn(PETSC_SUCCESS);
731: }
733: /*@
734: SNESSetUpMatrices - ensures that matrices are available for `SNES` Newton-like methods, this is called by `SNESSetUp_XXX()`
736: Collective
738: Input Parameter:
739: . snes - `SNES` object to configure
741: Level: developer
743: Note:
744: If the matrices do not yet exist it attempts to create them based on options previously set for the `SNES` such as `-snes_mf`
746: Developer Note:
747: The functionality of this routine overlaps in a confusing way with the functionality of `SNESSetUpMatrixFree_Private()` which is called by
748: `SNESSetUp()` but sometimes `SNESSetUpMatrices()` is called without `SNESSetUp()` being called. A refactorization to simplify the
749: logic that handles the matrix-free case is desirable.
751: .seealso: [](ch_snes), `SNES`, `SNESSetUp()`
752: @*/
753: PetscErrorCode SNESSetUpMatrices(SNES snes)
754: {
755: DM dm;
756: DMSNES sdm;
758: PetscFunctionBegin;
759: PetscCall(SNESGetDM(snes, &dm));
760: PetscCall(DMGetDMSNES(dm, &sdm));
761: if (!snes->jacobian && snes->mf && !snes->mf_operator && !snes->jacobian_pre) {
762: Mat J;
763: void *functx;
764: PetscCall(MatCreateSNESMF(snes, &J));
765: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
766: PetscCall(MatSetFromOptions(J));
767: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
768: PetscCall(SNESSetJacobian(snes, J, J, NULL, NULL));
769: PetscCall(MatDestroy(&J));
770: } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
771: Mat J, B;
772: PetscCall(MatCreateSNESMF(snes, &J));
773: PetscCall(MatMFFDSetOptionsPrefix(J, ((PetscObject)snes)->prefix));
774: PetscCall(MatSetFromOptions(J));
775: PetscCall(DMCreateMatrix(snes->dm, &B));
776: /* sdm->computejacobian was already set to reach here */
777: PetscCall(SNESSetJacobian(snes, J, B, NULL, NULL));
778: PetscCall(MatDestroy(&J));
779: PetscCall(MatDestroy(&B));
780: } else if (!snes->jacobian_pre) {
781: PetscDS prob;
782: Mat J, B;
783: PetscBool hasPrec = PETSC_FALSE;
785: J = snes->jacobian;
786: PetscCall(DMGetDS(dm, &prob));
787: if (prob) PetscCall(PetscDSHasJacobianPreconditioner(prob, &hasPrec));
788: if (J) PetscCall(PetscObjectReference((PetscObject)J));
789: else if (hasPrec) PetscCall(DMCreateMatrix(snes->dm, &J));
790: PetscCall(DMCreateMatrix(snes->dm, &B));
791: PetscCall(SNESSetJacobian(snes, J ? J : B, B, NULL, NULL));
792: PetscCall(MatDestroy(&J));
793: PetscCall(MatDestroy(&B));
794: }
795: {
796: KSP ksp;
797: PetscCall(SNESGetKSP(snes, &ksp));
798: PetscCall(KSPSetComputeOperators(ksp, KSPComputeOperators_SNES, snes));
799: PetscCall(DMCoarsenHookAdd(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
800: }
801: PetscFunctionReturn(PETSC_SUCCESS);
802: }
804: static PetscErrorCode SNESMonitorPauseFinal_Internal(SNES snes)
805: {
806: PetscInt i;
808: PetscFunctionBegin;
809: if (!snes->pauseFinal) PetscFunctionReturn(PETSC_SUCCESS);
810: for (i = 0; i < snes->numbermonitors; ++i) {
811: PetscViewerAndFormat *vf = (PetscViewerAndFormat *)snes->monitorcontext[i];
812: PetscDraw draw;
813: PetscReal lpause;
815: if (!vf) continue;
816: if (vf->lg) {
817: if (!PetscCheckPointer(vf->lg, PETSC_OBJECT)) continue;
818: if (((PetscObject)vf->lg)->classid != PETSC_DRAWLG_CLASSID) continue;
819: PetscCall(PetscDrawLGGetDraw(vf->lg, &draw));
820: PetscCall(PetscDrawGetPause(draw, &lpause));
821: PetscCall(PetscDrawSetPause(draw, -1.0));
822: PetscCall(PetscDrawPause(draw));
823: PetscCall(PetscDrawSetPause(draw, lpause));
824: } else {
825: PetscBool isdraw;
827: if (!PetscCheckPointer(vf->viewer, PETSC_OBJECT)) continue;
828: if (((PetscObject)vf->viewer)->classid != PETSC_VIEWER_CLASSID) continue;
829: PetscCall(PetscObjectTypeCompare((PetscObject)vf->viewer, PETSCVIEWERDRAW, &isdraw));
830: if (!isdraw) continue;
831: PetscCall(PetscViewerDrawGetDraw(vf->viewer, 0, &draw));
832: PetscCall(PetscDrawGetPause(draw, &lpause));
833: PetscCall(PetscDrawSetPause(draw, -1.0));
834: PetscCall(PetscDrawPause(draw));
835: PetscCall(PetscDrawSetPause(draw, lpause));
836: }
837: }
838: PetscFunctionReturn(PETSC_SUCCESS);
839: }
841: /*@C
842: SNESMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user
844: Collective
846: Input Parameters:
847: + snes - `SNES` object you wish to monitor
848: . name - the monitor type one is seeking
849: . help - message indicating what monitoring is done
850: . manual - manual page for the monitor
851: . monitor - the monitor function
852: - 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
854: Calling sequence of `monitor`:
855: + snes - the nonlinear solver context
856: . it - the current iteration
857: . r - the current function norm
858: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
860: Calling sequence of `monitorsetup`:
861: + snes - the nonlinear solver context
862: - vf - a `PetscViewerAndFormat` struct that contains the `PetscViewer` and `PetscViewerFormat` to use
864: Options Database Key:
865: . -name - trigger the use of this monitor in `SNESSetFromOptions()`
867: Level: advanced
869: .seealso: [](ch_snes), `PetscOptionsGetViewer()`, `PetscOptionsGetReal()`, `PetscOptionsHasName()`, `PetscOptionsGetString()`,
870: `PetscOptionsGetIntArray()`, `PetscOptionsGetRealArray()`, `PetscOptionsBool()`
871: `PetscOptionsInt()`, `PetscOptionsString()`, `PetscOptionsReal()`,
872: `PetscOptionsName()`, `PetscOptionsBegin()`, `PetscOptionsEnd()`, `PetscOptionsHeadBegin()`,
873: `PetscOptionsStringArray()`, `PetscOptionsRealArray()`, `PetscOptionsScalar()`,
874: `PetscOptionsBoolGroupBegin()`, `PetscOptionsBoolGroup()`, `PetscOptionsBoolGroupEnd()`,
875: `PetscOptionsFList()`, `PetscOptionsEList()`
876: @*/
877: 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))
878: {
879: PetscViewer viewer;
880: PetscViewerFormat format;
881: PetscBool flg;
883: PetscFunctionBegin;
884: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, name, &viewer, &format, &flg));
885: if (flg) {
886: PetscViewerAndFormat *vf;
887: PetscCall(PetscViewerAndFormatCreate(viewer, format, &vf));
888: PetscCall(PetscOptionsRestoreViewer(&viewer));
889: if (monitorsetup) PetscCall((*monitorsetup)(snes, vf));
890: PetscCall(SNESMonitorSet(snes, (PetscErrorCode(*)(SNES, PetscInt, PetscReal, void *))monitor, vf, (PetscErrorCode(*)(void **))PetscViewerAndFormatDestroy));
891: }
892: PetscFunctionReturn(PETSC_SUCCESS);
893: }
895: PetscErrorCode SNESEWSetFromOptions_Private(SNESKSPEW *kctx, PetscBool print_api, MPI_Comm comm, const char *prefix)
896: {
897: const char *api = print_api ? "SNESKSPSetParametersEW" : NULL;
899: PetscFunctionBegin;
900: PetscOptionsBegin(comm, prefix, "Eisenstat and Walker type forcing options", "KSP");
901: PetscCall(PetscOptionsInt("-ksp_ew_version", "Version 1, 2 or 3", api, kctx->version, &kctx->version, NULL));
902: PetscCall(PetscOptionsReal("-ksp_ew_rtol0", "0 <= rtol0 < 1", api, kctx->rtol_0, &kctx->rtol_0, NULL));
903: kctx->rtol_max = PetscMax(kctx->rtol_0, kctx->rtol_max);
904: PetscCall(PetscOptionsReal("-ksp_ew_rtolmax", "0 <= rtolmax < 1", api, kctx->rtol_max, &kctx->rtol_max, NULL));
905: PetscCall(PetscOptionsReal("-ksp_ew_gamma", "0 <= gamma <= 1", api, kctx->gamma, &kctx->gamma, NULL));
906: PetscCall(PetscOptionsReal("-ksp_ew_alpha", "1 < alpha <= 2", api, kctx->alpha, &kctx->alpha, NULL));
907: PetscCall(PetscOptionsReal("-ksp_ew_alpha2", "alpha2", NULL, kctx->alpha2, &kctx->alpha2, NULL));
908: PetscCall(PetscOptionsReal("-ksp_ew_threshold", "0 < threshold < 1", api, kctx->threshold, &kctx->threshold, NULL));
909: PetscCall(PetscOptionsReal("-ksp_ew_v4_p1", "p1", NULL, kctx->v4_p1, &kctx->v4_p1, NULL));
910: PetscCall(PetscOptionsReal("-ksp_ew_v4_p2", "p2", NULL, kctx->v4_p2, &kctx->v4_p2, NULL));
911: PetscCall(PetscOptionsReal("-ksp_ew_v4_p3", "p3", NULL, kctx->v4_p3, &kctx->v4_p3, NULL));
912: PetscCall(PetscOptionsReal("-ksp_ew_v4_m1", "Scaling when rk-1 in [p2,p3)", NULL, kctx->v4_m1, &kctx->v4_m1, NULL));
913: PetscCall(PetscOptionsReal("-ksp_ew_v4_m2", "Scaling when rk-1 in [p3,+infty)", NULL, kctx->v4_m2, &kctx->v4_m2, NULL));
914: PetscCall(PetscOptionsReal("-ksp_ew_v4_m3", "Threshold for successive rtol (0.1 in Eq.7)", NULL, kctx->v4_m3, &kctx->v4_m3, NULL));
915: PetscCall(PetscOptionsReal("-ksp_ew_v4_m4", "Adaptation scaling (0.5 in Eq.7)", NULL, kctx->v4_m4, &kctx->v4_m4, NULL));
916: PetscOptionsEnd();
917: PetscFunctionReturn(PETSC_SUCCESS);
918: }
920: /*@
921: SNESSetFromOptions - Sets various `SNES` and `KSP` parameters from user options.
923: Collective
925: Input Parameter:
926: . snes - the `SNES` context
928: Options Database Keys:
929: + -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, `SNESType` for complete list
930: . -snes_stol <stol> - convergence tolerance in terms of the norm of the change in the solution between steps
931: . -snes_atol <abstol> - absolute tolerance of residual norm
932: . -snes_rtol <rtol> - relative decrease in tolerance norm from initial
933: . -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
934: . -snes_force_iteration <force> - force `SNESSolve()` to take at least one iteration
935: . -snes_max_it <max_it> - maximum number of iterations
936: . -snes_max_funcs <max_funcs> - maximum number of function evaluations
937: . -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
938: . -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
939: . -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
940: . -snes_lag_preconditioner_persists <true,false> - retains the -snes_lag_preconditioner information across multiple SNESSolve()
941: . -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
942: . -snes_lag_jacobian_persists <true,false> - retains the -snes_lag_jacobian information across multiple SNESSolve()
943: . -snes_tr_tol <trtol> - trust region tolerance
944: . -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.
945: . -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
946: . -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
947: . -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
948: . -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
949: . -snes_monitor_lg_residualnorm - plots residual norm at each iteration
950: . -snes_monitor_lg_range - plots residual norm at each iteration
951: . -snes_monitor_pause_final - Pauses all monitor drawing after the solver ends
952: . -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
953: . -snes_fd_color - use finite differences with coloring to compute Jacobian
954: . -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each `KSP` iteration
955: . -snes_converged_reason - print the reason for convergence/divergence after each solve
956: . -npc_snes_type <type> - the `SNES` type to use as a nonlinear preconditioner
957: . -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.
958: - -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.
960: Options Database Keys for Eisenstat-Walker method:
961: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
962: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
963: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
964: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
965: . -snes_ksp_ew_gamma <gamma> - Sets gamma
966: . -snes_ksp_ew_alpha <alpha> - Sets alpha
967: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
968: - -snes_ksp_ew_threshold <threshold> - Sets threshold
970: Level: beginner
972: Notes:
973: To see all options, run your program with the -help option or consult the users manual
975: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
976: and computing explicitly with
977: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
979: .seealso: [](ch_snes), `SNESType`, `SNESSetOptionsPrefix()`, `SNESResetFromOptions()`, `SNES`, `SNESCreate()`, `MatCreateSNESMF()`, `MatFDColoring`
980: @*/
981: PetscErrorCode SNESSetFromOptions(SNES snes)
982: {
983: PetscBool flg, pcset, persist, set;
984: PetscInt i, indx, lag, grids;
985: const char *deft = SNESNEWTONLS;
986: const char *convtests[] = {"default", "skip", "correct_pressure"};
987: SNESKSPEW *kctx = NULL;
988: char type[256], monfilename[PETSC_MAX_PATH_LEN], ewprefix[256];
989: PCSide pcside;
990: const char *optionsprefix;
992: PetscFunctionBegin;
994: PetscCall(SNESRegisterAll());
995: PetscObjectOptionsBegin((PetscObject)snes);
996: if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
997: PetscCall(PetscOptionsFList("-snes_type", "Nonlinear solver method", "SNESSetType", SNESList, deft, type, 256, &flg));
998: if (flg) {
999: PetscCall(SNESSetType(snes, type));
1000: } else if (!((PetscObject)snes)->type_name) {
1001: PetscCall(SNESSetType(snes, deft));
1002: }
1003: PetscCall(PetscOptionsReal("-snes_stol", "Stop if step length less than", "SNESSetTolerances", snes->stol, &snes->stol, NULL));
1004: PetscCall(PetscOptionsReal("-snes_atol", "Stop if function norm less than", "SNESSetTolerances", snes->abstol, &snes->abstol, NULL));
1006: PetscCall(PetscOptionsReal("-snes_rtol", "Stop if decrease in function norm less than", "SNESSetTolerances", snes->rtol, &snes->rtol, NULL));
1007: PetscCall(PetscOptionsReal("-snes_divergence_tolerance", "Stop if residual norm increases by this factor", "SNESSetDivergenceTolerance", snes->divtol, &snes->divtol, NULL));
1008: PetscCall(PetscOptionsInt("-snes_max_it", "Maximum iterations", "SNESSetTolerances", snes->max_its, &snes->max_its, NULL));
1009: PetscCall(PetscOptionsInt("-snes_max_funcs", "Maximum function evaluations", "SNESSetTolerances", snes->max_funcs, &snes->max_funcs, NULL));
1010: PetscCall(PetscOptionsInt("-snes_max_fail", "Maximum nonlinear step failures", "SNESSetMaxNonlinearStepFailures", snes->maxFailures, &snes->maxFailures, NULL));
1011: PetscCall(PetscOptionsInt("-snes_max_linear_solve_fail", "Maximum failures in linear solves allowed", "SNESSetMaxLinearSolveFailures", snes->maxLinearSolveFailures, &snes->maxLinearSolveFailures, NULL));
1012: PetscCall(PetscOptionsBool("-snes_error_if_not_converged", "Generate error if solver does not converge", "SNESSetErrorIfNotConverged", snes->errorifnotconverged, &snes->errorifnotconverged, NULL));
1013: PetscCall(PetscOptionsBool("-snes_force_iteration", "Force SNESSolve() to take at least one iteration", "SNESSetForceIteration", snes->forceiteration, &snes->forceiteration, NULL));
1014: PetscCall(PetscOptionsBool("-snes_check_jacobian_domain_error", "Check Jacobian domain error after Jacobian evaluation", "SNESCheckJacobianDomainError", snes->checkjacdomainerror, &snes->checkjacdomainerror, NULL));
1016: PetscCall(PetscOptionsInt("-snes_lag_preconditioner", "How often to rebuild preconditioner", "SNESSetLagPreconditioner", snes->lagpreconditioner, &lag, &flg));
1017: if (flg) {
1018: 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");
1019: PetscCall(SNESSetLagPreconditioner(snes, lag));
1020: }
1021: PetscCall(PetscOptionsBool("-snes_lag_preconditioner_persists", "Preconditioner lagging through multiple SNES solves", "SNESSetLagPreconditionerPersists", snes->lagjac_persist, &persist, &flg));
1022: if (flg) PetscCall(SNESSetLagPreconditionerPersists(snes, persist));
1023: PetscCall(PetscOptionsInt("-snes_lag_jacobian", "How often to rebuild Jacobian", "SNESSetLagJacobian", snes->lagjacobian, &lag, &flg));
1024: if (flg) {
1025: 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");
1026: PetscCall(SNESSetLagJacobian(snes, lag));
1027: }
1028: PetscCall(PetscOptionsBool("-snes_lag_jacobian_persists", "Jacobian lagging through multiple SNES solves", "SNESSetLagJacobianPersists", snes->lagjac_persist, &persist, &flg));
1029: if (flg) PetscCall(SNESSetLagJacobianPersists(snes, persist));
1031: PetscCall(PetscOptionsInt("-snes_grid_sequence", "Use grid sequencing to generate initial guess", "SNESSetGridSequence", snes->gridsequence, &grids, &flg));
1032: if (flg) PetscCall(SNESSetGridSequence(snes, grids));
1034: PetscCall(PetscOptionsEList("-snes_convergence_test", "Convergence test", "SNESSetConvergenceTest", convtests, PETSC_STATIC_ARRAY_LENGTH(convtests), "default", &indx, &flg));
1035: if (flg) {
1036: switch (indx) {
1037: case 0:
1038: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedDefault, NULL, NULL));
1039: break;
1040: case 1:
1041: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedSkip, NULL, NULL));
1042: break;
1043: case 2:
1044: PetscCall(SNESSetConvergenceTest(snes, SNESConvergedCorrectPressure, NULL, NULL));
1045: break;
1046: }
1047: }
1049: PetscCall(PetscOptionsEList("-snes_norm_schedule", "SNES Norm schedule", "SNESSetNormSchedule", SNESNormSchedules, 5, "function", &indx, &flg));
1050: if (flg) PetscCall(SNESSetNormSchedule(snes, (SNESNormSchedule)indx));
1052: PetscCall(PetscOptionsEList("-snes_function_type", "SNES Norm schedule", "SNESSetFunctionType", SNESFunctionTypes, 2, "unpreconditioned", &indx, &flg));
1053: if (flg) PetscCall(SNESSetFunctionType(snes, (SNESFunctionType)indx));
1055: kctx = (SNESKSPEW *)snes->kspconvctx;
1057: PetscCall(PetscOptionsBool("-snes_ksp_ew", "Use Eisentat-Walker linear system convergence test", "SNESKSPSetUseEW", snes->ksp_ewconv, &snes->ksp_ewconv, NULL));
1059: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1060: PetscCall(PetscSNPrintf(ewprefix, sizeof(ewprefix), "%s%s", optionsprefix ? optionsprefix : "", "snes_"));
1061: PetscCall(SNESEWSetFromOptions_Private(kctx, PETSC_TRUE, PetscObjectComm((PetscObject)snes), ewprefix));
1063: flg = PETSC_FALSE;
1064: PetscCall(PetscOptionsBool("-snes_monitor_cancel", "Remove all monitors", "SNESMonitorCancel", flg, &flg, &set));
1065: if (set && flg) PetscCall(SNESMonitorCancel(snes));
1067: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor", "Monitor norm of function", "SNESMonitorDefault", SNESMonitorDefault, SNESMonitorDefaultSetUp));
1068: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_short", "Monitor norm of function with fewer digits", "SNESMonitorDefaultShort", SNESMonitorDefaultShort, NULL));
1069: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_range", "Monitor range of elements of function", "SNESMonitorRange", SNESMonitorRange, NULL));
1071: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_ratio", "Monitor ratios of the norm of function for consecutive steps", "SNESMonitorRatio", SNESMonitorRatio, SNESMonitorRatioSetUp));
1072: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_field", "Monitor norm of function (split into fields)", "SNESMonitorDefaultField", SNESMonitorDefaultField, NULL));
1073: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution", "View solution at each iteration", "SNESMonitorSolution", SNESMonitorSolution, NULL));
1074: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_solution_update", "View correction at each iteration", "SNESMonitorSolutionUpdate", SNESMonitorSolutionUpdate, NULL));
1075: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_residual", "View residual at each iteration", "SNESMonitorResidual", SNESMonitorResidual, NULL));
1076: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_jacupdate_spectrum", "Print the change in the spectrum of the Jacobian", "SNESMonitorJacUpdateSpectrum", SNESMonitorJacUpdateSpectrum, NULL));
1077: PetscCall(SNESMonitorSetFromOptions(snes, "-snes_monitor_fields", "Monitor norm of function per field", "SNESMonitorSet", SNESMonitorFields, NULL));
1078: PetscCall(PetscOptionsBool("-snes_monitor_pause_final", "Pauses all draw monitors at the final iterate", "SNESMonitorPauseFinal_Internal", PETSC_FALSE, &snes->pauseFinal, NULL));
1080: PetscCall(PetscOptionsString("-snes_monitor_python", "Use Python function", "SNESMonitorSet", NULL, monfilename, sizeof(monfilename), &flg));
1081: if (flg) PetscCall(PetscPythonMonitorSet((PetscObject)snes, monfilename));
1083: flg = PETSC_FALSE;
1084: PetscCall(PetscOptionsBool("-snes_monitor_lg_range", "Plot function range at each iteration", "SNESMonitorLGRange", flg, &flg, NULL));
1085: if (flg) {
1086: PetscViewer ctx;
1088: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, NULL, PETSC_DECIDE, PETSC_DECIDE, 400, 300, &ctx));
1089: PetscCall(SNESMonitorSet(snes, SNESMonitorLGRange, ctx, (PetscErrorCode(*)(void **))PetscViewerDestroy));
1090: }
1092: flg = PETSC_FALSE;
1093: PetscCall(PetscOptionsBool("-snes_converged_reason_view_cancel", "Remove all converged reason viewers", "SNESConvergedReasonViewCancel", flg, &flg, &set));
1094: if (set && flg) PetscCall(SNESConvergedReasonViewCancel(snes));
1096: flg = PETSC_FALSE;
1097: PetscCall(PetscOptionsBool("-snes_fd", "Use finite differences (slow) to compute Jacobian", "SNESComputeJacobianDefault", flg, &flg, NULL));
1098: if (flg) {
1099: void *functx;
1100: DM dm;
1101: PetscCall(SNESGetDM(snes, &dm));
1102: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1103: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
1104: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefault, functx));
1105: PetscCall(PetscInfo(snes, "Setting default finite difference Jacobian matrix\n"));
1106: }
1108: flg = PETSC_FALSE;
1109: PetscCall(PetscOptionsBool("-snes_fd_function", "Use finite differences (slow) to compute function from user objective", "SNESObjectiveComputeFunctionDefaultFD", flg, &flg, NULL));
1110: if (flg) PetscCall(SNESSetFunction(snes, NULL, SNESObjectiveComputeFunctionDefaultFD, NULL));
1112: flg = PETSC_FALSE;
1113: PetscCall(PetscOptionsBool("-snes_fd_color", "Use finite differences with coloring to compute Jacobian", "SNESComputeJacobianDefaultColor", flg, &flg, NULL));
1114: if (flg) {
1115: DM dm;
1116: PetscCall(SNESGetDM(snes, &dm));
1117: PetscCall(DMSNESUnsetJacobianContext_Internal(dm));
1118: PetscCall(SNESSetJacobian(snes, snes->jacobian, snes->jacobian_pre, SNESComputeJacobianDefaultColor, NULL));
1119: PetscCall(PetscInfo(snes, "Setting default finite difference coloring Jacobian matrix\n"));
1120: }
1122: flg = PETSC_FALSE;
1123: PetscCall(PetscOptionsBool("-snes_mf_operator", "Use a Matrix-Free Jacobian with user-provided preconditioner matrix", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf_operator, &flg));
1124: if (flg && snes->mf_operator) {
1125: snes->mf_operator = PETSC_TRUE;
1126: snes->mf = PETSC_TRUE;
1127: }
1128: flg = PETSC_FALSE;
1129: PetscCall(PetscOptionsBool("-snes_mf", "Use a Matrix-Free Jacobian with no preconditioner matrix", "SNESSetUseMatrixFree", PETSC_FALSE, &snes->mf, &flg));
1130: if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1131: PetscCall(PetscOptionsInt("-snes_mf_version", "Matrix-Free routines version 1 or 2", "None", snes->mf_version, &snes->mf_version, NULL));
1133: flg = PETSC_FALSE;
1134: PetscCall(SNESGetNPCSide(snes, &pcside));
1135: PetscCall(PetscOptionsEnum("-snes_npc_side", "SNES nonlinear preconditioner side", "SNESSetNPCSide", PCSides, (PetscEnum)pcside, (PetscEnum *)&pcside, &flg));
1136: if (flg) PetscCall(SNESSetNPCSide(snes, pcside));
1138: #if defined(PETSC_HAVE_SAWS)
1139: /*
1140: Publish convergence information using SAWs
1141: */
1142: flg = PETSC_FALSE;
1143: PetscCall(PetscOptionsBool("-snes_monitor_saws", "Publish SNES progress using SAWs", "SNESMonitorSet", flg, &flg, NULL));
1144: if (flg) {
1145: void *ctx;
1146: PetscCall(SNESMonitorSAWsCreate(snes, &ctx));
1147: PetscCall(SNESMonitorSet(snes, SNESMonitorSAWs, ctx, SNESMonitorSAWsDestroy));
1148: }
1149: #endif
1150: #if defined(PETSC_HAVE_SAWS)
1151: {
1152: PetscBool set;
1153: flg = PETSC_FALSE;
1154: PetscCall(PetscOptionsBool("-snes_saws_block", "Block for SAWs at end of SNESSolve", "PetscObjectSAWsBlock", ((PetscObject)snes)->amspublishblock, &flg, &set));
1155: if (set) PetscCall(PetscObjectSAWsSetBlock((PetscObject)snes, flg));
1156: }
1157: #endif
1159: for (i = 0; i < numberofsetfromoptions; i++) PetscCall((*othersetfromoptions[i])(snes));
1161: PetscTryTypeMethod(snes, setfromoptions, PetscOptionsObject);
1163: /* process any options handlers added with PetscObjectAddOptionsHandler() */
1164: PetscCall(PetscObjectProcessOptionsHandlers((PetscObject)snes, PetscOptionsObject));
1165: PetscOptionsEnd();
1167: if (snes->linesearch) {
1168: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
1169: PetscCall(SNESLineSearchSetFromOptions(snes->linesearch));
1170: }
1172: if (snes->usesksp) {
1173: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
1174: PetscCall(KSPSetOperators(snes->ksp, snes->jacobian, snes->jacobian_pre));
1175: PetscCall(KSPSetFromOptions(snes->ksp));
1176: }
1178: /* if user has set the SNES NPC type via options database, create it. */
1179: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
1180: PetscCall(PetscOptionsHasName(((PetscObject)snes)->options, optionsprefix, "-npc_snes_type", &pcset));
1181: if (pcset && (!snes->npc)) PetscCall(SNESGetNPC(snes, &snes->npc));
1182: if (snes->npc) PetscCall(SNESSetFromOptions(snes->npc));
1183: snes->setfromoptionscalled++;
1184: PetscFunctionReturn(PETSC_SUCCESS);
1185: }
1187: /*@
1188: SNESResetFromOptions - Sets various `SNES` and `KSP` parameters from user options ONLY if the `SNESSetFromOptions()` was previously called
1190: Collective
1192: Input Parameter:
1193: . snes - the `SNES` context
1195: Level: advanced
1197: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESSetOptionsPrefix()`
1198: @*/
1199: PetscErrorCode SNESResetFromOptions(SNES snes)
1200: {
1201: PetscFunctionBegin;
1202: if (snes->setfromoptionscalled) PetscCall(SNESSetFromOptions(snes));
1203: PetscFunctionReturn(PETSC_SUCCESS);
1204: }
1206: /*@C
1207: SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1208: the nonlinear solvers.
1210: Logically Collective; No Fortran Support
1212: Input Parameters:
1213: + snes - the `SNES` context
1214: . compute - function to compute the context
1215: - destroy - function to destroy the context
1217: Calling sequence of `compute`:
1218: + snes - the `SNES` context
1219: - ctx - context to be computed
1221: Calling sequence of `destroy`:
1222: . ctx - context to be computed by `compute()`
1224: Level: intermediate
1226: Note:
1227: This routine is useful if you are performing grid sequencing or using `SNESFAS` and need the appropriate context generated for each level.
1229: Use `SNESSetApplicationContext()` to see the context immediately
1231: .seealso: [](ch_snes), `SNESGetApplicationContext()`, `SNESSetApplicationContext()`
1232: @*/
1233: PetscErrorCode SNESSetComputeApplicationContext(SNES snes, PetscErrorCode (*compute)(SNES snes, void **ctx), PetscErrorCode (*destroy)(void **ctx))
1234: {
1235: PetscFunctionBegin;
1237: snes->ops->usercompute = compute;
1238: snes->ops->userdestroy = destroy;
1239: PetscFunctionReturn(PETSC_SUCCESS);
1240: }
1242: /*@
1243: SNESSetApplicationContext - Sets the optional user-defined context for the nonlinear solvers.
1245: Logically Collective
1247: Input Parameters:
1248: + snes - the `SNES` context
1249: - usrP - optional user context
1251: Level: intermediate
1253: Notes:
1254: Users can provide a context when constructing the `SNES` options and then access it inside their function, Jacobian, or other evaluation function
1255: with `SNESGetApplicationContext()`
1257: To provide a function that computes the context for you use `SNESSetComputeApplicationContext()`
1259: Fortran Note:
1260: You must write a Fortran interface definition for this
1261: function that tells Fortran the Fortran derived data type that you are passing in as the `usrP` argument.
1263: .seealso: [](ch_snes), `SNES`, `SNESSetComputeApplicationContext()`, `SNESGetApplicationContext()`
1264: @*/
1265: PetscErrorCode SNESSetApplicationContext(SNES snes, void *usrP)
1266: {
1267: KSP ksp;
1269: PetscFunctionBegin;
1271: PetscCall(SNESGetKSP(snes, &ksp));
1272: PetscCall(KSPSetApplicationContext(ksp, usrP));
1273: snes->user = usrP;
1274: PetscFunctionReturn(PETSC_SUCCESS);
1275: }
1277: /*@
1278: SNESGetApplicationContext - Gets the user-defined context for the
1279: nonlinear solvers set with `SNESGetApplicationContext()` or `SNESSetComputeApplicationContext()`
1281: Not Collective
1283: Input Parameter:
1284: . snes - `SNES` context
1286: Output Parameter:
1287: . usrP - user context
1289: Level: intermediate
1291: Fortran Note:
1292: You must write a Fortran interface definition for this
1293: function that tells Fortran the Fortran derived data type that you are passing in as the `usrP` argument.
1295: .seealso: [](ch_snes), `SNESSetApplicationContext()`, `SNESSetComputeApplicationContext()`
1296: @*/
1297: PetscErrorCode SNESGetApplicationContext(SNES snes, void *usrP)
1298: {
1299: PetscFunctionBegin;
1301: *(void **)usrP = snes->user;
1302: PetscFunctionReturn(PETSC_SUCCESS);
1303: }
1305: /*@
1306: SNESSetUseMatrixFree - indicates that `SNES` should use matrix-free finite difference matrix-vector products to apply the Jacobian.
1308: Logically Collective
1310: Input Parameters:
1311: + snes - `SNES` context
1312: . mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1313: - 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
1314: this option no matrix-element based preconditioners can be used in the linear solve since the matrix won't be explicitly available
1316: Options Database Keys:
1317: + -snes_mf_operator - use matrix-free only for the mat operator
1318: . -snes_mf - use matrix-free for both the mat and pmat operator
1319: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1320: - -snes_fd - compute the Jacobian via finite differences (slow)
1322: Level: intermediate
1324: Note:
1325: `SNES` supports three approaches for computing (approximate) Jacobians: user provided via `SNESSetJacobian()`, matrix-free using `MatCreateSNESMF()`,
1326: and computing explicitly with
1327: finite differences and coloring using `MatFDColoring`. It is also possible to use automatic differentiation and the `MatFDColoring` object.
1329: .seealso: [](ch_snes), `SNES`, `SNESGetUseMatrixFree()`, `MatCreateSNESMF()`, `SNESComputeJacobianDefaultColor()`, `MatFDColoring`
1330: @*/
1331: PetscErrorCode SNESSetUseMatrixFree(SNES snes, PetscBool mf_operator, PetscBool mf)
1332: {
1333: PetscFunctionBegin;
1337: snes->mf = mf_operator ? PETSC_TRUE : mf;
1338: snes->mf_operator = mf_operator;
1339: PetscFunctionReturn(PETSC_SUCCESS);
1340: }
1342: /*@
1343: SNESGetUseMatrixFree - indicates if the `SNES` uses matrix-free finite difference matrix vector products to apply the Jacobian.
1345: Not Collective, but the resulting flags will be the same on all MPI processes
1347: Input Parameter:
1348: . snes - `SNES` context
1350: Output Parameters:
1351: + mf_operator - use matrix-free only for the Amat used by `SNESSetJacobian()`, this means the user provided Pmat will continue to be used
1352: - mf - use matrix-free for both the Amat and Pmat used by `SNESSetJacobian()`, both the Amat and Pmat set in `SNESSetJacobian()` will be ignored
1354: Level: intermediate
1356: .seealso: [](ch_snes), `SNES`, `SNESSetUseMatrixFree()`, `MatCreateSNESMF()`
1357: @*/
1358: PetscErrorCode SNESGetUseMatrixFree(SNES snes, PetscBool *mf_operator, PetscBool *mf)
1359: {
1360: PetscFunctionBegin;
1362: if (mf) *mf = snes->mf;
1363: if (mf_operator) *mf_operator = snes->mf_operator;
1364: PetscFunctionReturn(PETSC_SUCCESS);
1365: }
1367: /*@
1368: SNESGetIterationNumber - Gets the number of nonlinear iterations completed in the current or most recent `SNESSolve()`
1370: Not Collective
1372: Input Parameter:
1373: . snes - `SNES` context
1375: Output Parameter:
1376: . iter - iteration number
1378: Level: intermediate
1380: Notes:
1381: For example, during the computation of iteration 2 this would return 1.
1383: This is useful for using lagged Jacobians (where one does not recompute the
1384: Jacobian at each `SNES` iteration). For example, the code
1385: .vb
1386: ierr = SNESGetIterationNumber(snes,&it);
1387: if (!(it % 2)) {
1388: [compute Jacobian here]
1389: }
1390: .ve
1391: can be used in your function that computes the Jacobian to cause the Jacobian to be
1392: recomputed every second `SNES` iteration. See also `SNESSetLagJacobian()`
1394: After the `SNES` solve is complete this will return the number of nonlinear iterations used.
1396: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetLagJacobian()`, `SNESGetLinearSolveIterations()`, `SNESSetMonitor()`
1397: @*/
1398: PetscErrorCode SNESGetIterationNumber(SNES snes, PetscInt *iter)
1399: {
1400: PetscFunctionBegin;
1402: PetscAssertPointer(iter, 2);
1403: *iter = snes->iter;
1404: PetscFunctionReturn(PETSC_SUCCESS);
1405: }
1407: /*@
1408: SNESSetIterationNumber - Sets the current iteration number.
1410: Not Collective
1412: Input Parameters:
1413: + snes - `SNES` context
1414: - iter - iteration number
1416: Level: developer
1418: Note:
1419: This should only be called inside a `SNES` nonlinear solver.
1421: .seealso: [](ch_snes), `SNESGetLinearSolveIterations()`
1422: @*/
1423: PetscErrorCode SNESSetIterationNumber(SNES snes, PetscInt iter)
1424: {
1425: PetscFunctionBegin;
1427: PetscCall(PetscObjectSAWsTakeAccess((PetscObject)snes));
1428: snes->iter = iter;
1429: PetscCall(PetscObjectSAWsGrantAccess((PetscObject)snes));
1430: PetscFunctionReturn(PETSC_SUCCESS);
1431: }
1433: /*@
1434: SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1435: attempted by the nonlinear solver in the current or most recent `SNESSolve()` .
1437: Not Collective
1439: Input Parameter:
1440: . snes - `SNES` context
1442: Output Parameter:
1443: . nfails - number of unsuccessful steps attempted
1445: Level: intermediate
1447: Note:
1448: This counter is reset to zero for each successive call to `SNESSolve()`.
1450: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1451: `SNESSetMaxNonlinearStepFailures()`, `SNESGetMaxNonlinearStepFailures()`
1452: @*/
1453: PetscErrorCode SNESGetNonlinearStepFailures(SNES snes, PetscInt *nfails)
1454: {
1455: PetscFunctionBegin;
1457: PetscAssertPointer(nfails, 2);
1458: *nfails = snes->numFailures;
1459: PetscFunctionReturn(PETSC_SUCCESS);
1460: }
1462: /*@
1463: SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1464: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1466: Not Collective
1468: Input Parameters:
1469: + snes - `SNES` context
1470: - maxFails - maximum of unsuccessful steps
1472: Options Database Key:
1473: . -snes_max_fail <n> - maximum number of unsuccessful steps allowed
1475: Level: intermediate
1477: Developer Note:
1478: The options database key is wrong for this function name
1480: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1481: `SNESGetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1482: @*/
1483: PetscErrorCode SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1484: {
1485: PetscFunctionBegin;
1487: snes->maxFailures = maxFails;
1488: PetscFunctionReturn(PETSC_SUCCESS);
1489: }
1491: /*@
1492: SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1493: attempted by the nonlinear solver before it gives up and returns unconverged or generates an error
1495: Not Collective
1497: Input Parameter:
1498: . snes - `SNES` context
1500: Output Parameter:
1501: . maxFails - maximum of unsuccessful steps
1503: Level: intermediate
1505: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`,
1506: `SNESSetMaxNonlinearStepFailures()`, `SNESGetNonlinearStepFailures()`
1507: @*/
1508: PetscErrorCode SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1509: {
1510: PetscFunctionBegin;
1512: PetscAssertPointer(maxFails, 2);
1513: *maxFails = snes->maxFailures;
1514: PetscFunctionReturn(PETSC_SUCCESS);
1515: }
1517: /*@
1518: SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1519: done by the `SNES` object in the current or most recent `SNESSolve()`
1521: Not Collective
1523: Input Parameter:
1524: . snes - `SNES` context
1526: Output Parameter:
1527: . nfuncs - number of evaluations
1529: Level: intermediate
1531: Note:
1532: Reset every time `SNESSolve()` is called unless `SNESSetCountersReset()` is used.
1534: .seealso: [](ch_snes), `SNES`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`, `SNESGetLinearSolveFailures()`, `SNESSetCountersReset()`
1535: @*/
1536: PetscErrorCode SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1537: {
1538: PetscFunctionBegin;
1540: PetscAssertPointer(nfuncs, 2);
1541: *nfuncs = snes->nfuncs;
1542: PetscFunctionReturn(PETSC_SUCCESS);
1543: }
1545: /*@
1546: SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1547: linear solvers in the current or most recent `SNESSolve()`
1549: Not Collective
1551: Input Parameter:
1552: . snes - `SNES` context
1554: Output Parameter:
1555: . nfails - number of failed solves
1557: Options Database Key:
1558: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1560: Level: intermediate
1562: Note:
1563: This counter is reset to zero for each successive call to `SNESSolve()`.
1565: .seealso: [](ch_snes), `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`
1566: @*/
1567: PetscErrorCode SNESGetLinearSolveFailures(SNES snes, PetscInt *nfails)
1568: {
1569: PetscFunctionBegin;
1571: PetscAssertPointer(nfails, 2);
1572: *nfails = snes->numLinearSolveFailures;
1573: PetscFunctionReturn(PETSC_SUCCESS);
1574: }
1576: /*@
1577: SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1578: allowed before `SNES` returns with a diverged reason of `SNES_DIVERGED_LINEAR_SOLVE`
1580: Logically Collective
1582: Input Parameters:
1583: + snes - `SNES` context
1584: - maxFails - maximum allowed linear solve failures
1586: Options Database Key:
1587: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated
1589: Level: intermediate
1591: Note:
1592: By default this is 0; that is `SNES` returns on the first failed linear solve
1594: Developer Note:
1595: The options database key is wrong for this function name
1597: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESGetLinearSolveIterations()`
1598: @*/
1599: PetscErrorCode SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1600: {
1601: PetscFunctionBegin;
1604: snes->maxLinearSolveFailures = maxFails;
1605: PetscFunctionReturn(PETSC_SUCCESS);
1606: }
1608: /*@
1609: SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1610: are allowed before `SNES` returns as unsuccessful
1612: Not Collective
1614: Input Parameter:
1615: . snes - `SNES` context
1617: Output Parameter:
1618: . maxFails - maximum of unsuccessful solves allowed
1620: Level: intermediate
1622: Note:
1623: By default this is 1; that is `SNES` returns on the first failed linear solve
1625: .seealso: [](ch_snes), `SNESSetErrorIfNotConverged()`, `SNESGetLinearSolveFailures()`, `SNESGetLinearSolveIterations()`, `SNESSetMaxLinearSolveFailures()`,
1626: @*/
1627: PetscErrorCode SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1628: {
1629: PetscFunctionBegin;
1631: PetscAssertPointer(maxFails, 2);
1632: *maxFails = snes->maxLinearSolveFailures;
1633: PetscFunctionReturn(PETSC_SUCCESS);
1634: }
1636: /*@
1637: SNESGetLinearSolveIterations - Gets the total number of linear iterations
1638: used by the nonlinear solver in the most recent `SNESSolve()`
1640: Not Collective
1642: Input Parameter:
1643: . snes - `SNES` context
1645: Output Parameter:
1646: . lits - number of linear iterations
1648: Level: intermediate
1650: Notes:
1651: This counter is reset to zero for each successive call to `SNESSolve()` unless `SNESSetCountersReset()` is used.
1653: 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
1654: then call `KSPGetIterationNumber()` after the failed solve.
1656: .seealso: [](ch_snes), `SNES`, `SNESGetIterationNumber()`, `SNESGetLinearSolveFailures()`, `SNESGetMaxLinearSolveFailures()`, `SNESSetCountersReset()`
1657: @*/
1658: PetscErrorCode SNESGetLinearSolveIterations(SNES snes, PetscInt *lits)
1659: {
1660: PetscFunctionBegin;
1662: PetscAssertPointer(lits, 2);
1663: *lits = snes->linear_its;
1664: PetscFunctionReturn(PETSC_SUCCESS);
1665: }
1667: /*@
1668: SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1669: are reset every time `SNESSolve()` is called.
1671: Logically Collective
1673: Input Parameters:
1674: + snes - `SNES` context
1675: - reset - whether to reset the counters or not, defaults to `PETSC_TRUE`
1677: Level: developer
1679: .seealso: [](ch_snes), `SNESGetNumberFunctionEvals()`, `SNESGetLinearSolveIterations()`, `SNESGetNPC()`
1680: @*/
1681: PetscErrorCode SNESSetCountersReset(SNES snes, PetscBool reset)
1682: {
1683: PetscFunctionBegin;
1686: snes->counters_reset = reset;
1687: PetscFunctionReturn(PETSC_SUCCESS);
1688: }
1690: /*@
1691: SNESSetKSP - Sets a `KSP` context for the `SNES` object to use
1693: Not Collective, but the `SNES` and `KSP` objects must live on the same `MPI_Comm`
1695: Input Parameters:
1696: + snes - the `SNES` context
1697: - ksp - the `KSP` context
1699: Level: developer
1701: Notes:
1702: The `SNES` object already has its `KSP` object, you can obtain with `SNESGetKSP()`
1703: so this routine is rarely needed.
1705: The `KSP` object that is already in the `SNES` object has its reference count
1706: decreased by one when this is called.
1708: .seealso: [](ch_snes), `SNES`, `KSP`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`
1709: @*/
1710: PetscErrorCode SNESSetKSP(SNES snes, KSP ksp)
1711: {
1712: PetscFunctionBegin;
1715: PetscCheckSameComm(snes, 1, ksp, 2);
1716: PetscCall(PetscObjectReference((PetscObject)ksp));
1717: if (snes->ksp) PetscCall(PetscObjectDereference((PetscObject)snes->ksp));
1718: snes->ksp = ksp;
1719: PetscFunctionReturn(PETSC_SUCCESS);
1720: }
1722: /*@
1723: SNESCreate - Creates a nonlinear solver context used to manage a set of nonlinear solves
1725: Collective
1727: Input Parameter:
1728: . comm - MPI communicator
1730: Output Parameter:
1731: . outsnes - the new `SNES` context
1733: Options Database Keys:
1734: + -snes_mf - Activates default matrix-free Jacobian-vector products, and no preconditioning matrix
1735: . -snes_mf_operator - Activates default matrix-free Jacobian-vector products, and a user-provided preconditioning matrix
1736: as set by `SNESSetJacobian()`
1737: . -snes_fd_coloring - uses a relative fast computation of the Jacobian using finite differences and a graph coloring
1738: - -snes_fd - Uses (slow!) finite differences to compute Jacobian
1740: Level: beginner
1742: Developer Notes:
1743: `SNES` always creates a `KSP` object even though many `SNES` methods do not use it. This is
1744: unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1745: particular method does use `KSP` and regulates if the information about the `KSP` is printed
1746: in `SNESView()`.
1748: `TSSetFromOptions()` does call `SNESSetFromOptions()` which can lead to users being confused
1749: by help messages about meaningless `SNES` options.
1751: `SNES` always creates the snes->kspconvctx even though it is used by only one type. This should be fixed.
1753: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESDestroy()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
1754: @*/
1755: PetscErrorCode SNESCreate(MPI_Comm comm, SNES *outsnes)
1756: {
1757: SNES snes;
1758: SNESKSPEW *kctx;
1760: PetscFunctionBegin;
1761: PetscAssertPointer(outsnes, 2);
1762: *outsnes = NULL;
1763: PetscCall(SNESInitializePackage());
1765: PetscCall(PetscHeaderCreate(snes, SNES_CLASSID, "SNES", "Nonlinear solver", "SNES", comm, SNESDestroy, SNESView));
1767: snes->ops->converged = SNESConvergedDefault;
1768: snes->usesksp = PETSC_TRUE;
1769: snes->tolerancesset = PETSC_FALSE;
1770: snes->max_its = 50;
1771: snes->max_funcs = 10000;
1772: snes->norm = 0.0;
1773: snes->xnorm = 0.0;
1774: snes->ynorm = 0.0;
1775: snes->normschedule = SNES_NORM_ALWAYS;
1776: snes->functype = SNES_FUNCTION_DEFAULT;
1777: snes->rtol = PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8;
1778: snes->ttol = 0.0;
1779: snes->abstol = PetscDefined(USE_REAL_SINGLE) ? 1.e-25 : 1.e-50;
1780: snes->stol = PetscDefined(USE_REAL_SINGLE) ? 1.e-5 : 1.e-8;
1781: snes->deltatol = PetscDefined(USE_REAL_SINGLE) ? 1.e-6 : 1.e-12;
1782: snes->divtol = 1.e4;
1783: snes->rnorm0 = 0;
1784: snes->nfuncs = 0;
1785: snes->numFailures = 0;
1786: snes->maxFailures = 1;
1787: snes->linear_its = 0;
1788: snes->lagjacobian = 1;
1789: snes->jac_iter = 0;
1790: snes->lagjac_persist = PETSC_FALSE;
1791: snes->lagpreconditioner = 1;
1792: snes->pre_iter = 0;
1793: snes->lagpre_persist = PETSC_FALSE;
1794: snes->numbermonitors = 0;
1795: snes->numberreasonviews = 0;
1796: snes->data = NULL;
1797: snes->setupcalled = PETSC_FALSE;
1798: snes->ksp_ewconv = PETSC_FALSE;
1799: snes->nwork = 0;
1800: snes->work = NULL;
1801: snes->nvwork = 0;
1802: snes->vwork = NULL;
1803: snes->conv_hist_len = 0;
1804: snes->conv_hist_max = 0;
1805: snes->conv_hist = NULL;
1806: snes->conv_hist_its = NULL;
1807: snes->conv_hist_reset = PETSC_TRUE;
1808: snes->counters_reset = PETSC_TRUE;
1809: snes->vec_func_init_set = PETSC_FALSE;
1810: snes->reason = SNES_CONVERGED_ITERATING;
1811: snes->npcside = PC_RIGHT;
1812: snes->setfromoptionscalled = 0;
1814: snes->mf = PETSC_FALSE;
1815: snes->mf_operator = PETSC_FALSE;
1816: snes->mf_version = 1;
1818: snes->numLinearSolveFailures = 0;
1819: snes->maxLinearSolveFailures = 1;
1821: snes->vizerotolerance = 1.e-8;
1822: snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;
1824: /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1825: snes->alwayscomputesfinalresidual = PETSC_FALSE;
1827: /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1828: PetscCall(PetscNew(&kctx));
1830: snes->kspconvctx = (void *)kctx;
1831: kctx->version = 2;
1832: kctx->rtol_0 = 0.3; /* Eisenstat and Walker suggest rtol_0=.5, but
1833: this was too large for some test cases */
1834: kctx->rtol_last = 0.0;
1835: kctx->rtol_max = 0.9;
1836: kctx->gamma = 1.0;
1837: kctx->alpha = 0.5 * (1.0 + PetscSqrtReal(5.0));
1838: kctx->alpha2 = kctx->alpha;
1839: kctx->threshold = 0.1;
1840: kctx->lresid_last = 0.0;
1841: kctx->norm_last = 0.0;
1843: kctx->rk_last = 0.0;
1844: kctx->rk_last_2 = 0.0;
1845: kctx->rtol_last_2 = 0.0;
1846: kctx->v4_p1 = 0.1;
1847: kctx->v4_p2 = 0.4;
1848: kctx->v4_p3 = 0.7;
1849: kctx->v4_m1 = 0.8;
1850: kctx->v4_m2 = 0.5;
1851: kctx->v4_m3 = 0.1;
1852: kctx->v4_m4 = 0.5;
1854: *outsnes = snes;
1855: PetscFunctionReturn(PETSC_SUCCESS);
1856: }
1858: /*@C
1859: SNESSetFunction - Sets the function evaluation routine and function
1860: vector for use by the `SNES` routines in solving systems of nonlinear
1861: equations.
1863: Logically Collective
1865: Input Parameters:
1866: + snes - the `SNES` context
1867: . r - vector to store function values, may be `NULL`
1868: . f - function evaluation routine; for calling sequence see `SNESFunctionFn`
1869: - ctx - [optional] user-defined context for private data for the
1870: function evaluation routine (may be `NULL`)
1872: Level: beginner
1874: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetPicard()`, `SNESFunctionFn`
1875: @*/
1876: PetscErrorCode SNESSetFunction(SNES snes, Vec r, SNESFunctionFn *f, void *ctx)
1877: {
1878: DM dm;
1880: PetscFunctionBegin;
1882: if (r) {
1884: PetscCheckSameComm(snes, 1, r, 2);
1885: PetscCall(PetscObjectReference((PetscObject)r));
1886: PetscCall(VecDestroy(&snes->vec_func));
1887: snes->vec_func = r;
1888: }
1889: PetscCall(SNESGetDM(snes, &dm));
1890: PetscCall(DMSNESSetFunction(dm, f, ctx));
1891: if (f == SNESPicardComputeFunction) PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
1892: PetscFunctionReturn(PETSC_SUCCESS);
1893: }
1895: /*@C
1896: SNESSetInitialFunction - Set an already computed function evaluation at the initial guess to be reused by `SNESSolve()`.
1898: Logically Collective
1900: Input Parameters:
1901: + snes - the `SNES` context
1902: - f - vector to store function value
1904: Level: developer
1906: Notes:
1907: This should not be modified during the solution procedure.
1909: This is used extensively in the `SNESFAS` hierarchy and in nonlinear preconditioning.
1911: .seealso: [](ch_snes), `SNES`, `SNESFAS`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetInitialFunctionNorm()`
1912: @*/
1913: PetscErrorCode SNESSetInitialFunction(SNES snes, Vec f)
1914: {
1915: Vec vec_func;
1917: PetscFunctionBegin;
1920: PetscCheckSameComm(snes, 1, f, 2);
1921: if (snes->npcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1922: snes->vec_func_init_set = PETSC_FALSE;
1923: PetscFunctionReturn(PETSC_SUCCESS);
1924: }
1925: PetscCall(SNESGetFunction(snes, &vec_func, NULL, NULL));
1926: PetscCall(VecCopy(f, vec_func));
1928: snes->vec_func_init_set = PETSC_TRUE;
1929: PetscFunctionReturn(PETSC_SUCCESS);
1930: }
1932: /*@
1933: SNESSetNormSchedule - Sets the `SNESNormSchedule` used in convergence and monitoring
1934: of the `SNES` method, when norms are computed in the solving process
1936: Logically Collective
1938: Input Parameters:
1939: + snes - the `SNES` context
1940: - normschedule - the frequency of norm computation
1942: Options Database Key:
1943: . -snes_norm_schedule <none, always, initialonly, finalonly, initialfinalonly> - set the schedule
1945: Level: advanced
1947: Notes:
1948: Only certain `SNES` methods support certain `SNESNormSchedules`. Most require evaluation
1949: of the nonlinear function and the taking of its norm at every iteration to
1950: even ensure convergence at all. However, methods such as custom Gauss-Seidel methods
1951: `SNESNGS` and the like do not require the norm of the function to be computed, and therefore
1952: may either be monitored for convergence or not. As these are often used as nonlinear
1953: preconditioners, monitoring the norm of their error is not a useful enterprise within
1954: their solution.
1956: .seealso: [](ch_snes), `SNESNormSchedule`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`
1957: @*/
1958: PetscErrorCode SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1959: {
1960: PetscFunctionBegin;
1962: snes->normschedule = normschedule;
1963: PetscFunctionReturn(PETSC_SUCCESS);
1964: }
1966: /*@
1967: SNESGetNormSchedule - Gets the `SNESNormSchedule` used in convergence and monitoring
1968: of the `SNES` method.
1970: Logically Collective
1972: Input Parameters:
1973: + snes - the `SNES` context
1974: - normschedule - the type of the norm used
1976: Level: advanced
1978: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
1979: @*/
1980: PetscErrorCode SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1981: {
1982: PetscFunctionBegin;
1984: *normschedule = snes->normschedule;
1985: PetscFunctionReturn(PETSC_SUCCESS);
1986: }
1988: /*@
1989: SNESSetFunctionNorm - Sets the last computed residual norm.
1991: Logically Collective
1993: Input Parameters:
1994: + snes - the `SNES` context
1995: - norm - the value of the norm
1997: Level: developer
1999: .seealso: [](ch_snes), `SNES`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2000: @*/
2001: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
2002: {
2003: PetscFunctionBegin;
2005: snes->norm = norm;
2006: PetscFunctionReturn(PETSC_SUCCESS);
2007: }
2009: /*@
2010: SNESGetFunctionNorm - Gets the last computed norm of the residual
2012: Not Collective
2014: Input Parameter:
2015: . snes - the `SNES` context
2017: Output Parameter:
2018: . norm - the last computed residual norm
2020: Level: developer
2022: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2023: @*/
2024: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
2025: {
2026: PetscFunctionBegin;
2028: PetscAssertPointer(norm, 2);
2029: *norm = snes->norm;
2030: PetscFunctionReturn(PETSC_SUCCESS);
2031: }
2033: /*@
2034: SNESGetUpdateNorm - Gets the last computed norm of the solution update
2036: Not Collective
2038: Input Parameter:
2039: . snes - the `SNES` context
2041: Output Parameter:
2042: . ynorm - the last computed update norm
2044: Level: developer
2046: Note:
2047: The new solution is the current solution plus the update, so this norm is an indication of the size of the update
2049: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`
2050: @*/
2051: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2052: {
2053: PetscFunctionBegin;
2055: PetscAssertPointer(ynorm, 2);
2056: *ynorm = snes->ynorm;
2057: PetscFunctionReturn(PETSC_SUCCESS);
2058: }
2060: /*@
2061: SNESGetSolutionNorm - Gets the last computed norm of the solution
2063: Not Collective
2065: Input Parameter:
2066: . snes - the `SNES` context
2068: Output Parameter:
2069: . xnorm - the last computed solution norm
2071: Level: developer
2073: .seealso: [](ch_snes), `SNES`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `SNESGetFunctionNorm()`, `SNESGetUpdateNorm()`
2074: @*/
2075: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2076: {
2077: PetscFunctionBegin;
2079: PetscAssertPointer(xnorm, 2);
2080: *xnorm = snes->xnorm;
2081: PetscFunctionReturn(PETSC_SUCCESS);
2082: }
2084: /*@C
2085: SNESSetFunctionType - Sets the `SNESFunctionType`
2086: of the `SNES` method.
2088: Logically Collective
2090: Input Parameters:
2091: + snes - the `SNES` context
2092: - type - the function type
2094: Level: developer
2096: Values of the function type\:
2097: + `SNES_FUNCTION_DEFAULT` - the default for the given `SNESType`
2098: . `SNES_FUNCTION_UNPRECONDITIONED` - an unpreconditioned function evaluation (this is the function provided with `SNESSetFunction()`
2099: - `SNES_FUNCTION_PRECONDITIONED` - a transformation of the function provided with `SNESSetFunction()`
2101: Note:
2102: Different `SNESType`s use this value in different ways
2104: .seealso: [](ch_snes), `SNES`, `SNESFunctionType`, `SNESGetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2105: @*/
2106: PetscErrorCode SNESSetFunctionType(SNES snes, SNESFunctionType type)
2107: {
2108: PetscFunctionBegin;
2110: snes->functype = type;
2111: PetscFunctionReturn(PETSC_SUCCESS);
2112: }
2114: /*@C
2115: SNESGetFunctionType - Gets the `SNESFunctionType` used in convergence and monitoring set with `SNESSetFunctionType()`
2116: of the SNES method.
2118: Logically Collective
2120: Input Parameters:
2121: + snes - the `SNES` context
2122: - type - the type of the function evaluation, see `SNESSetFunctionType()`
2124: Level: advanced
2126: .seealso: [](ch_snes), `SNESSetFunctionType()`, `SNESFunctionType`, `SNESSetNormSchedule()`, `SNESComputeFunction()`, `VecNorm()`, `SNESSetFunction()`, `SNESSetInitialFunction()`, `SNESNormSchedule`
2127: @*/
2128: PetscErrorCode SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2129: {
2130: PetscFunctionBegin;
2132: *type = snes->functype;
2133: PetscFunctionReturn(PETSC_SUCCESS);
2134: }
2136: /*@C
2137: SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2138: use with composed nonlinear solvers.
2140: Input Parameters:
2141: + snes - the `SNES` context, usually of the `SNESType` `SNESNGS`
2142: . f - function evaluation routine to apply Gauss-Seidel, see `SNESNGSFn` for calling sequence
2143: - ctx - [optional] user-defined context for private data for the
2144: smoother evaluation routine (may be `NULL`)
2146: Level: intermediate
2148: Note:
2149: The `SNESNGS` routines are used by the composed nonlinear solver to generate
2150: a problem appropriate update to the solution, particularly `SNESFAS`.
2152: .seealso: [](ch_snes), `SNESNGS`, `SNESGetNGS()`, `SNESNCG`, `SNESGetFunction()`, `SNESComputeNGS()`, `SNESNGSFn`
2153: @*/
2154: PetscErrorCode SNESSetNGS(SNES snes, SNESNGSFn *f, void *ctx)
2155: {
2156: DM dm;
2158: PetscFunctionBegin;
2160: PetscCall(SNESGetDM(snes, &dm));
2161: PetscCall(DMSNESSetNGS(dm, f, ctx));
2162: PetscFunctionReturn(PETSC_SUCCESS);
2163: }
2165: /*
2166: This is used for -snes_mf_operator; it uses a duplicate of snes->jacobian_pre because snes->jacobian_pre cannot be
2167: changed during the KSPSolve()
2168: */
2169: PetscErrorCode SNESPicardComputeMFFunction(SNES snes, Vec x, Vec f, void *ctx)
2170: {
2171: DM dm;
2172: DMSNES sdm;
2174: PetscFunctionBegin;
2175: PetscCall(SNESGetDM(snes, &dm));
2176: PetscCall(DMGetDMSNES(dm, &sdm));
2177: /* A(x)*x - b(x) */
2178: if (sdm->ops->computepfunction) {
2179: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2180: PetscCall(VecScale(f, -1.0));
2181: /* Cannot share nonzero pattern because of the possible use of SNESComputeJacobianDefault() */
2182: if (!snes->picard) PetscCall(MatDuplicate(snes->jacobian_pre, MAT_DO_NOT_COPY_VALUES, &snes->picard));
2183: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2184: PetscCall(MatMultAdd(snes->picard, x, f, f));
2185: } else {
2186: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->picard, snes->picard, sdm->pctx));
2187: PetscCall(MatMult(snes->picard, x, f));
2188: }
2189: PetscFunctionReturn(PETSC_SUCCESS);
2190: }
2192: PetscErrorCode SNESPicardComputeFunction(SNES snes, Vec x, Vec f, void *ctx)
2193: {
2194: DM dm;
2195: DMSNES sdm;
2197: PetscFunctionBegin;
2198: PetscCall(SNESGetDM(snes, &dm));
2199: PetscCall(DMGetDMSNES(dm, &sdm));
2200: /* A(x)*x - b(x) */
2201: if (sdm->ops->computepfunction) {
2202: PetscCallBack("SNES Picard callback function", (*sdm->ops->computepfunction)(snes, x, f, sdm->pctx));
2203: PetscCall(VecScale(f, -1.0));
2204: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2205: PetscCall(MatMultAdd(snes->jacobian_pre, x, f, f));
2206: } else {
2207: PetscCallBack("SNES Picard callback Jacobian", (*sdm->ops->computepjacobian)(snes, x, snes->jacobian, snes->jacobian_pre, sdm->pctx));
2208: PetscCall(MatMult(snes->jacobian_pre, x, f));
2209: }
2210: PetscFunctionReturn(PETSC_SUCCESS);
2211: }
2213: PetscErrorCode SNESPicardComputeJacobian(SNES snes, Vec x1, Mat J, Mat B, void *ctx)
2214: {
2215: PetscFunctionBegin;
2216: /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2217: /* must assembly if matrix-free to get the last SNES solution */
2218: PetscCall(MatAssemblyBegin(J, MAT_FINAL_ASSEMBLY));
2219: PetscCall(MatAssemblyEnd(J, MAT_FINAL_ASSEMBLY));
2220: PetscFunctionReturn(PETSC_SUCCESS);
2221: }
2223: /*@C
2224: SNESSetPicard - Use `SNES` to solve the system $A(x) x = bp(x) + b $ via a Picard type iteration (Picard linearization)
2226: Logically Collective
2228: Input Parameters:
2229: + snes - the `SNES` context
2230: . r - vector to store function values, may be `NULL`
2231: . bp - function evaluation routine, may be `NULL`, for the calling sequence see `SNESFunctionFn`
2232: . Amat - matrix with which A(x) x - bp(x) - b is to be computed
2233: . Pmat - matrix from which preconditioner is computed (usually the same as `Amat`)
2234: . J - function to compute matrix values, for the calling sequence see `SNESJacobianFn`
2235: - ctx - [optional] user-defined context for private data for the function evaluation routine (may be `NULL`)
2237: Level: intermediate
2239: Notes:
2240: It is often better to provide the nonlinear function F() and some approximation to its Jacobian directly and use
2241: 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.
2243: One can call `SNESSetPicard()` or `SNESSetFunction()` (and possibly `SNESSetJacobian()`) but cannot call both
2245: Solves the equation $A(x) x = bp(x) - b$ via the defect correction algorithm $A(x^{n}) (x^{n+1} - x^{n}) = bp(x^{n}) + b - A(x^{n})x^{n}$.
2246: When an exact solver is used this corresponds to the "classic" Picard $A(x^{n}) x^{n+1} = bp(x^{n}) + b$ iteration.
2248: Run with `-snes_mf_operator` to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.
2250: We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2251: the direct Picard iteration $A(x^n) x^{n+1} = bp(x^n) + b$
2253: 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
2254: 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
2255: different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument \:-).
2257: 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
2258: A(x^{n}) is used to build the preconditioner
2260: When used with `-snes_fd` this will compute the true Jacobian (very slowly one column at a time) and thus represent Newton's method.
2262: 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
2263: 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
2264: 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`.
2265: See the comment in src/snes/tutorials/ex15.c.
2267: .seealso: [](ch_snes), `SNES`, `SNESGetFunction()`, `SNESSetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESGetPicard()`, `SNESLineSearchPreCheckPicard()`,
2268: `SNESFunctionFn`, `SNESJacobianFn`
2269: @*/
2270: PetscErrorCode SNESSetPicard(SNES snes, Vec r, SNESFunctionFn *bp, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
2271: {
2272: DM dm;
2274: PetscFunctionBegin;
2276: PetscCall(SNESGetDM(snes, &dm));
2277: PetscCall(DMSNESSetPicard(dm, bp, J, ctx));
2278: PetscCall(DMSNESSetMFFunction(dm, SNESPicardComputeMFFunction, ctx));
2279: PetscCall(SNESSetFunction(snes, r, SNESPicardComputeFunction, ctx));
2280: PetscCall(SNESSetJacobian(snes, Amat, Pmat, SNESPicardComputeJacobian, ctx));
2281: PetscFunctionReturn(PETSC_SUCCESS);
2282: }
2284: /*@C
2285: SNESGetPicard - Returns the context for the Picard iteration
2287: Not Collective, but `Vec` is parallel if `SNES` is parallel. Collective if `Vec` is requested, but has not been created yet.
2289: Input Parameter:
2290: . snes - the `SNES` context
2292: Output Parameters:
2293: + r - the function (or `NULL`)
2294: . f - the function (or `NULL`); for calling sequence see `SNESFunctionFn`
2295: . Amat - the matrix used to defined the operation A(x) x - b(x) (or `NULL`)
2296: . Pmat - the matrix from which the preconditioner will be constructed (or `NULL`)
2297: . J - the function for matrix evaluation (or `NULL`); for calling sequence see `SNESJacobianFn`
2298: - ctx - the function context (or `NULL`)
2300: Level: advanced
2302: .seealso: [](ch_snes), `SNESSetFunction()`, `SNESSetPicard()`, `SNESGetFunction()`, `SNESGetJacobian()`, `SNESGetDM()`, `SNESFunctionFn`, `SNESJacobianFn`
2303: @*/
2304: PetscErrorCode SNESGetPicard(SNES snes, Vec *r, SNESFunctionFn **f, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
2305: {
2306: DM dm;
2308: PetscFunctionBegin;
2310: PetscCall(SNESGetFunction(snes, r, NULL, NULL));
2311: PetscCall(SNESGetJacobian(snes, Amat, Pmat, NULL, NULL));
2312: PetscCall(SNESGetDM(snes, &dm));
2313: PetscCall(DMSNESGetPicard(dm, f, J, ctx));
2314: PetscFunctionReturn(PETSC_SUCCESS);
2315: }
2317: /*@C
2318: SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the nonlinear problem
2320: Logically Collective
2322: Input Parameters:
2323: + snes - the `SNES` context
2324: . func - function evaluation routine, see `SNESInitialGuessFn` for the calling sequence
2325: - ctx - [optional] user-defined context for private data for the
2326: function evaluation routine (may be `NULL`)
2328: Level: intermediate
2330: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESInitialGuessFn`
2331: @*/
2332: PetscErrorCode SNESSetComputeInitialGuess(SNES snes, SNESInitialGuessFn *func, void *ctx)
2333: {
2334: PetscFunctionBegin;
2336: if (func) snes->ops->computeinitialguess = func;
2337: if (ctx) snes->initialguessP = ctx;
2338: PetscFunctionReturn(PETSC_SUCCESS);
2339: }
2341: /*@C
2342: SNESGetRhs - Gets the vector for solving F(x) = `rhs`. If `rhs` is not set
2343: it assumes a zero right-hand side.
2345: Logically Collective
2347: Input Parameter:
2348: . snes - the `SNES` context
2350: Output Parameter:
2351: . rhs - the right-hand side vector or `NULL` if there is no right-hand side vector
2353: Level: intermediate
2355: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`, `SNESComputeFunction()`, `SNESSetJacobian()`, `SNESSetFunction()`
2356: @*/
2357: PetscErrorCode SNESGetRhs(SNES snes, Vec *rhs)
2358: {
2359: PetscFunctionBegin;
2361: PetscAssertPointer(rhs, 2);
2362: *rhs = snes->vec_rhs;
2363: PetscFunctionReturn(PETSC_SUCCESS);
2364: }
2366: /*@
2367: SNESComputeFunction - Calls the function that has been set with `SNESSetFunction()`.
2369: Collective
2371: Input Parameters:
2372: + snes - the `SNES` context
2373: - x - input vector
2375: Output Parameter:
2376: . y - function vector, as set by `SNESSetFunction()`
2378: Level: developer
2380: Notes:
2381: `SNESComputeFunction()` is typically used within nonlinear solvers
2382: implementations, so users would not generally call this routine themselves.
2384: When solving for $F(x) = b$, this routine computes $y = F(x) - b$.
2386: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeMFFunction()`
2387: @*/
2388: PetscErrorCode SNESComputeFunction(SNES snes, Vec x, Vec y)
2389: {
2390: DM dm;
2391: DMSNES sdm;
2393: PetscFunctionBegin;
2397: PetscCheckSameComm(snes, 1, x, 2);
2398: PetscCheckSameComm(snes, 1, y, 3);
2399: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2401: PetscCall(SNESGetDM(snes, &dm));
2402: PetscCall(DMGetDMSNES(dm, &sdm));
2403: 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().");
2404: if (sdm->ops->computefunction) {
2405: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2406: PetscCall(VecLockReadPush(x));
2407: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2408: snes->domainerror = PETSC_FALSE;
2409: {
2410: void *ctx;
2411: SNESFunctionFn *computefunction;
2412: PetscCall(DMSNESGetFunction(dm, &computefunction, &ctx));
2413: PetscCallBack("SNES callback function", (*computefunction)(snes, x, y, ctx));
2414: }
2415: PetscCall(VecLockReadPop(x));
2416: if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2417: } else /* if (snes->vec_rhs) */ {
2418: PetscCall(MatMult(snes->jacobian, x, y));
2419: }
2420: if (snes->vec_rhs) PetscCall(VecAXPY(y, -1.0, snes->vec_rhs));
2421: snes->nfuncs++;
2422: /*
2423: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2424: propagate the value to all processes
2425: */
2426: if (snes->domainerror) PetscCall(VecSetInf(y));
2427: PetscFunctionReturn(PETSC_SUCCESS);
2428: }
2430: /*@
2431: SNESComputeMFFunction - Calls the function that has been set with `SNESSetMFFunction()`.
2433: Collective
2435: Input Parameters:
2436: + snes - the `SNES` context
2437: - x - input vector
2439: Output Parameter:
2440: . y - function vector, as set by `SNESSetMFFunction()`
2442: Level: developer
2444: Notes:
2445: `SNESComputeMFFunction()` is used within the matrix-vector products called by the matrix created with `MatCreateSNESMF()`
2446: so users would not generally call this routine themselves.
2448: Since this function is intended for use with finite differencing it does not subtract the right-hand side vector provided with `SNESSolve()`
2449: while `SNESComputeFunction()` does. As such, this routine cannot be used with `MatMFFDSetBase()` with a provided F function value even if it applies the
2450: 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.
2452: .seealso: [](ch_snes), `SNES`, `SNESSetFunction()`, `SNESGetFunction()`, `SNESComputeFunction()`, `MatCreateSNESMF`
2453: @*/
2454: PetscErrorCode SNESComputeMFFunction(SNES snes, Vec x, Vec y)
2455: {
2456: DM dm;
2457: DMSNES sdm;
2459: PetscFunctionBegin;
2463: PetscCheckSameComm(snes, 1, x, 2);
2464: PetscCheckSameComm(snes, 1, y, 3);
2465: PetscCall(VecValidValues_Internal(x, 2, PETSC_TRUE));
2467: PetscCall(SNESGetDM(snes, &dm));
2468: PetscCall(DMGetDMSNES(dm, &sdm));
2469: PetscCall(PetscLogEventBegin(SNES_FunctionEval, snes, x, y, 0));
2470: PetscCall(VecLockReadPush(x));
2471: /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2472: snes->domainerror = PETSC_FALSE;
2473: PetscCallBack("SNES callback function", (*sdm->ops->computemffunction)(snes, x, y, sdm->mffunctionctx));
2474: PetscCall(VecLockReadPop(x));
2475: PetscCall(PetscLogEventEnd(SNES_FunctionEval, snes, x, y, 0));
2476: snes->nfuncs++;
2477: /*
2478: domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2479: propagate the value to all processes
2480: */
2481: if (snes->domainerror) PetscCall(VecSetInf(y));
2482: PetscFunctionReturn(PETSC_SUCCESS);
2483: }
2485: /*@
2486: SNESComputeNGS - Calls the Gauss-Seidel function that has been set with `SNESSetNGS()`.
2488: Collective
2490: Input Parameters:
2491: + snes - the `SNES` context
2492: . x - input vector
2493: - b - rhs vector
2495: Output Parameter:
2496: . x - new solution vector
2498: Level: developer
2500: Note:
2501: `SNESComputeNGS()` is typically used within composed nonlinear solver
2502: implementations, so most users would not generally call this routine
2503: themselves.
2505: .seealso: [](ch_snes), `SNESNGSFn`, `SNESSetNGS()`, `SNESComputeFunction()`, `SNESNGS`
2506: @*/
2507: PetscErrorCode SNESComputeNGS(SNES snes, Vec b, Vec x)
2508: {
2509: DM dm;
2510: DMSNES sdm;
2512: PetscFunctionBegin;
2516: PetscCheckSameComm(snes, 1, x, 3);
2517: if (b) PetscCheckSameComm(snes, 1, b, 2);
2518: if (b) PetscCall(VecValidValues_Internal(b, 2, PETSC_TRUE));
2519: PetscCall(PetscLogEventBegin(SNES_NGSEval, snes, x, b, 0));
2520: PetscCall(SNESGetDM(snes, &dm));
2521: PetscCall(DMGetDMSNES(dm, &sdm));
2522: PetscCheck(sdm->ops->computegs, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2523: if (b) PetscCall(VecLockReadPush(b));
2524: PetscCallBack("SNES callback NGS", (*sdm->ops->computegs)(snes, x, b, sdm->gsctx));
2525: if (b) PetscCall(VecLockReadPop(b));
2526: PetscCall(PetscLogEventEnd(SNES_NGSEval, snes, x, b, 0));
2527: PetscFunctionReturn(PETSC_SUCCESS);
2528: }
2530: static PetscErrorCode SNESComputeFunction_FD(SNES snes, Vec Xin, Vec G)
2531: {
2532: Vec X;
2533: PetscScalar *g;
2534: PetscReal f, f2;
2535: PetscInt low, high, N, i;
2536: PetscBool flg;
2537: PetscReal h = .5 * PETSC_SQRT_MACHINE_EPSILON;
2539: PetscFunctionBegin;
2540: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_fd_delta", &h, &flg));
2541: PetscCall(VecDuplicate(Xin, &X));
2542: PetscCall(VecCopy(Xin, X));
2543: PetscCall(VecGetSize(X, &N));
2544: PetscCall(VecGetOwnershipRange(X, &low, &high));
2545: PetscCall(VecSetOption(X, VEC_IGNORE_OFF_PROC_ENTRIES, PETSC_TRUE));
2546: PetscCall(VecGetArray(G, &g));
2547: for (i = 0; i < N; i++) {
2548: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2549: PetscCall(VecAssemblyBegin(X));
2550: PetscCall(VecAssemblyEnd(X));
2551: PetscCall(SNESComputeObjective(snes, X, &f));
2552: PetscCall(VecSetValue(X, i, 2.0 * h, ADD_VALUES));
2553: PetscCall(VecAssemblyBegin(X));
2554: PetscCall(VecAssemblyEnd(X));
2555: PetscCall(SNESComputeObjective(snes, X, &f2));
2556: PetscCall(VecSetValue(X, i, -h, ADD_VALUES));
2557: PetscCall(VecAssemblyBegin(X));
2558: PetscCall(VecAssemblyEnd(X));
2559: if (i >= low && i < high) g[i - low] = (f2 - f) / (2.0 * h);
2560: }
2561: PetscCall(VecRestoreArray(G, &g));
2562: PetscCall(VecDestroy(&X));
2563: PetscFunctionReturn(PETSC_SUCCESS);
2564: }
2566: PetscErrorCode SNESTestFunction(SNES snes)
2567: {
2568: Vec x, g1, g2, g3;
2569: PetscBool complete_print = PETSC_FALSE, test = PETSC_FALSE;
2570: PetscReal hcnorm, fdnorm, hcmax, fdmax, diffmax, diffnorm;
2571: PetscScalar dot;
2572: MPI_Comm comm;
2573: PetscViewer viewer, mviewer;
2574: PetscViewerFormat format;
2575: PetscInt tabs;
2576: static PetscBool directionsprinted = PETSC_FALSE;
2577: SNESObjectiveFn *objective;
2579: PetscFunctionBegin;
2580: PetscCall(SNESGetObjective(snes, &objective, NULL));
2581: if (!objective) PetscFunctionReturn(PETSC_SUCCESS);
2583: PetscObjectOptionsBegin((PetscObject)snes);
2584: PetscCall(PetscOptionsName("-snes_test_function", "Compare hand-coded and finite difference function", "None", &test));
2585: PetscCall(PetscOptionsViewer("-snes_test_function_view", "View difference between hand-coded and finite difference function element entries", "None", &mviewer, &format, &complete_print));
2586: PetscOptionsEnd();
2587: if (!test) {
2588: if (complete_print) PetscCall(PetscViewerDestroy(&mviewer));
2589: PetscFunctionReturn(PETSC_SUCCESS);
2590: }
2592: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2593: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2594: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2595: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2596: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Function -------------\n"));
2597: if (!complete_print && !directionsprinted) {
2598: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_function_view and optionally -snes_test_function <threshold> to show difference\n"));
2599: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference function entries greater than <threshold>.\n"));
2600: }
2601: if (!directionsprinted) {
2602: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Function, if (for double precision runs) ||F - Ffd||/||F|| is\n"));
2603: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Function is probably correct.\n"));
2604: directionsprinted = PETSC_TRUE;
2605: }
2606: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2608: PetscCall(SNESGetSolution(snes, &x));
2609: PetscCall(VecDuplicate(x, &g1));
2610: PetscCall(VecDuplicate(x, &g2));
2611: PetscCall(VecDuplicate(x, &g3));
2612: PetscCall(SNESComputeFunction(snes, x, g1));
2613: PetscCall(SNESComputeFunction_FD(snes, x, g2));
2615: PetscCall(VecNorm(g2, NORM_2, &fdnorm));
2616: PetscCall(VecNorm(g1, NORM_2, &hcnorm));
2617: PetscCall(VecNorm(g2, NORM_INFINITY, &fdmax));
2618: PetscCall(VecNorm(g1, NORM_INFINITY, &hcmax));
2619: PetscCall(VecDot(g1, g2, &dot));
2620: PetscCall(VecCopy(g1, g3));
2621: PetscCall(VecAXPY(g3, -1.0, g2));
2622: PetscCall(VecNorm(g3, NORM_2, &diffnorm));
2623: PetscCall(VecNorm(g3, NORM_INFINITY, &diffmax));
2624: PetscCall(PetscViewerASCIIPrintf(viewer, " ||Ffd|| %g, ||F|| = %g, angle cosine = (Ffd'F)/||Ffd||||F|| = %g\n", (double)fdnorm, (double)hcnorm, (double)(PetscRealPart(dot) / (fdnorm * hcnorm))));
2625: PetscCall(PetscViewerASCIIPrintf(viewer, " 2-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffnorm / PetscMax(hcnorm, fdnorm)), (double)diffnorm));
2626: PetscCall(PetscViewerASCIIPrintf(viewer, " max-norm ||F - Ffd||/||F|| = %g, ||F - Ffd|| = %g\n", (double)(diffmax / PetscMax(hcmax, fdmax)), (double)diffmax));
2628: if (complete_print) {
2629: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded function ----------\n"));
2630: PetscCall(VecView(g1, mviewer));
2631: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference function ----------\n"));
2632: PetscCall(VecView(g2, mviewer));
2633: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference function ----------\n"));
2634: PetscCall(VecView(g3, mviewer));
2635: }
2636: PetscCall(VecDestroy(&g1));
2637: PetscCall(VecDestroy(&g2));
2638: PetscCall(VecDestroy(&g3));
2640: if (complete_print) {
2641: PetscCall(PetscViewerPopFormat(mviewer));
2642: PetscCall(PetscViewerDestroy(&mviewer));
2643: }
2644: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2645: PetscFunctionReturn(PETSC_SUCCESS);
2646: }
2648: PetscErrorCode SNESTestJacobian(SNES snes)
2649: {
2650: Mat A, B, C, D, jacobian;
2651: Vec x = snes->vec_sol, f;
2652: PetscReal nrm, gnorm;
2653: PetscReal threshold = 1.e-5;
2654: MatType mattype;
2655: PetscInt m, n, M, N;
2656: void *functx;
2657: PetscBool complete_print = PETSC_FALSE, threshold_print = PETSC_FALSE, test = PETSC_FALSE, flg, istranspose;
2658: PetscViewer viewer, mviewer;
2659: MPI_Comm comm;
2660: PetscInt tabs;
2661: static PetscBool directionsprinted = PETSC_FALSE;
2662: PetscViewerFormat format;
2664: PetscFunctionBegin;
2665: PetscObjectOptionsBegin((PetscObject)snes);
2666: PetscCall(PetscOptionsName("-snes_test_jacobian", "Compare hand-coded and finite difference Jacobians", "None", &test));
2667: PetscCall(PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold, NULL));
2668: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display", "-snes_test_jacobian_view", "3.13", NULL));
2669: PetscCall(PetscOptionsViewer("-snes_test_jacobian_view", "View difference between hand-coded and finite difference Jacobians element entries", "None", &mviewer, &format, &complete_print));
2670: PetscCall(PetscOptionsDeprecated("-snes_test_jacobian_display_threshold", "-snes_test_jacobian", "3.13", "-snes_test_jacobian accepts an optional threshold (since v3.10)"));
2671: 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));
2672: PetscOptionsEnd();
2673: if (!test) PetscFunctionReturn(PETSC_SUCCESS);
2675: PetscCall(PetscObjectGetComm((PetscObject)snes, &comm));
2676: PetscCall(PetscViewerASCIIGetStdout(comm, &viewer));
2677: PetscCall(PetscViewerASCIIGetTab(viewer, &tabs));
2678: PetscCall(PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel));
2679: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian -------------\n"));
2680: if (!complete_print && !directionsprinted) {
2681: PetscCall(PetscViewerASCIIPrintf(viewer, " Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n"));
2682: PetscCall(PetscViewerASCIIPrintf(viewer, " of hand-coded and finite difference Jacobian entries greater than <threshold>.\n"));
2683: }
2684: if (!directionsprinted) {
2685: PetscCall(PetscViewerASCIIPrintf(viewer, " Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n"));
2686: PetscCall(PetscViewerASCIIPrintf(viewer, " O(1.e-8), the hand-coded Jacobian is probably correct.\n"));
2687: directionsprinted = PETSC_TRUE;
2688: }
2689: if (complete_print) PetscCall(PetscViewerPushFormat(mviewer, format));
2691: PetscCall(PetscObjectTypeCompare((PetscObject)snes->jacobian, MATMFFD, &flg));
2692: if (!flg) jacobian = snes->jacobian;
2693: else jacobian = snes->jacobian_pre;
2695: if (!x) PetscCall(MatCreateVecs(jacobian, &x, NULL));
2696: else PetscCall(PetscObjectReference((PetscObject)x));
2697: PetscCall(VecDuplicate(x, &f));
2699: /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2700: PetscCall(SNESComputeFunction(snes, x, f));
2701: PetscCall(VecDestroy(&f));
2702: PetscCall(PetscObjectTypeCompare((PetscObject)snes, SNESKSPTRANSPOSEONLY, &istranspose));
2703: while (jacobian) {
2704: Mat JT = NULL, Jsave = NULL;
2706: if (istranspose) {
2707: PetscCall(MatCreateTranspose(jacobian, &JT));
2708: Jsave = jacobian;
2709: jacobian = JT;
2710: }
2711: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)jacobian, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPISBAIJ, ""));
2712: if (flg) {
2713: A = jacobian;
2714: PetscCall(PetscObjectReference((PetscObject)A));
2715: } else {
2716: PetscCall(MatComputeOperator(jacobian, MATAIJ, &A));
2717: }
2719: PetscCall(MatGetType(A, &mattype));
2720: PetscCall(MatGetSize(A, &M, &N));
2721: PetscCall(MatGetLocalSize(A, &m, &n));
2722: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &B));
2723: PetscCall(MatSetType(B, mattype));
2724: PetscCall(MatSetSizes(B, m, n, M, N));
2725: PetscCall(MatSetBlockSizesFromMats(B, A, A));
2726: PetscCall(MatSetUp(B));
2727: PetscCall(MatSetOption(B, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2729: PetscCall(SNESGetFunction(snes, NULL, NULL, &functx));
2730: PetscCall(SNESComputeJacobianDefault(snes, x, B, B, functx));
2732: PetscCall(MatDuplicate(B, MAT_COPY_VALUES, &D));
2733: PetscCall(MatAYPX(D, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2734: PetscCall(MatNorm(D, NORM_FROBENIUS, &nrm));
2735: PetscCall(MatNorm(A, NORM_FROBENIUS, &gnorm));
2736: PetscCall(MatDestroy(&D));
2737: if (!gnorm) gnorm = 1; /* just in case */
2738: PetscCall(PetscViewerASCIIPrintf(viewer, " ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n", (double)(nrm / gnorm), (double)nrm));
2740: if (complete_print) {
2741: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded Jacobian ----------\n"));
2742: PetscCall(MatView(A, mviewer));
2743: PetscCall(PetscViewerASCIIPrintf(viewer, " Finite difference Jacobian ----------\n"));
2744: PetscCall(MatView(B, mviewer));
2745: }
2747: if (threshold_print || complete_print) {
2748: PetscInt Istart, Iend, *ccols, bncols, cncols, j, row;
2749: PetscScalar *cvals;
2750: const PetscInt *bcols;
2751: const PetscScalar *bvals;
2753: PetscCall(MatCreate(PetscObjectComm((PetscObject)A), &C));
2754: PetscCall(MatSetType(C, mattype));
2755: PetscCall(MatSetSizes(C, m, n, M, N));
2756: PetscCall(MatSetBlockSizesFromMats(C, A, A));
2757: PetscCall(MatSetUp(C));
2758: PetscCall(MatSetOption(C, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
2760: PetscCall(MatAYPX(B, -1.0, A, DIFFERENT_NONZERO_PATTERN));
2761: PetscCall(MatGetOwnershipRange(B, &Istart, &Iend));
2763: for (row = Istart; row < Iend; row++) {
2764: PetscCall(MatGetRow(B, row, &bncols, &bcols, &bvals));
2765: PetscCall(PetscMalloc2(bncols, &ccols, bncols, &cvals));
2766: for (j = 0, cncols = 0; j < bncols; j++) {
2767: if (PetscAbsScalar(bvals[j]) > threshold) {
2768: ccols[cncols] = bcols[j];
2769: cvals[cncols] = bvals[j];
2770: cncols += 1;
2771: }
2772: }
2773: if (cncols) PetscCall(MatSetValues(C, 1, &row, cncols, ccols, cvals, INSERT_VALUES));
2774: PetscCall(MatRestoreRow(B, row, &bncols, &bcols, &bvals));
2775: PetscCall(PetscFree2(ccols, cvals));
2776: }
2777: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
2778: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
2779: PetscCall(PetscViewerASCIIPrintf(viewer, " Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n", (double)threshold));
2780: PetscCall(MatView(C, complete_print ? mviewer : viewer));
2781: PetscCall(MatDestroy(&C));
2782: }
2783: PetscCall(MatDestroy(&A));
2784: PetscCall(MatDestroy(&B));
2785: PetscCall(MatDestroy(&JT));
2786: if (Jsave) jacobian = Jsave;
2787: if (jacobian != snes->jacobian_pre) {
2788: jacobian = snes->jacobian_pre;
2789: PetscCall(PetscViewerASCIIPrintf(viewer, " ---------- Testing Jacobian for preconditioner -------------\n"));
2790: } else jacobian = NULL;
2791: }
2792: PetscCall(VecDestroy(&x));
2793: if (complete_print) PetscCall(PetscViewerPopFormat(mviewer));
2794: if (mviewer) PetscCall(PetscOptionsRestoreViewer(&mviewer));
2795: PetscCall(PetscViewerASCIISetTab(viewer, tabs));
2796: PetscFunctionReturn(PETSC_SUCCESS);
2797: }
2799: /*@
2800: SNESComputeJacobian - Computes the Jacobian matrix that has been set with `SNESSetJacobian()`.
2802: Collective
2804: Input Parameters:
2805: + snes - the `SNES` context
2806: - X - input vector
2808: Output Parameters:
2809: + A - Jacobian matrix
2810: - B - optional matrix for building the preconditioner, usually the same as `A`
2812: Options Database Keys:
2813: + -snes_lag_preconditioner <lag> - how often to rebuild preconditioner
2814: . -snes_lag_jacobian <lag> - how often to rebuild Jacobian
2815: . -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.
2816: . -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
2817: . -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2818: . -snes_compare_explicit_draw - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2819: . -snes_compare_explicit_contour - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2820: . -snes_compare_operator - Make the comparison options above use the operator instead of the preconditioning matrix
2821: . -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2822: . -snes_compare_coloring_display - Compute the finite difference Jacobian using coloring and display verbose differences
2823: . -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2824: . -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2825: . -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by `-snes_compare_coloring_threshold`
2826: . -snes_compare_coloring_draw - Compute the finite difference Jacobian using coloring and draw differences
2827: - -snes_compare_coloring_draw_contour - Compute the finite difference Jacobian using coloring and show contours of matrices and differences
2829: Level: developer
2831: Note:
2832: Most users should not need to explicitly call this routine, as it
2833: is used internally within the nonlinear solvers.
2835: Developer Note:
2836: 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
2837: with the `SNESType` of test that has been removed.
2839: .seealso: [](ch_snes), `SNESSetJacobian()`, `KSPSetOperators()`, `MatStructure`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobian()`
2840: @*/
2841: PetscErrorCode SNESComputeJacobian(SNES snes, Vec X, Mat A, Mat B)
2842: {
2843: PetscBool flag;
2844: DM dm;
2845: DMSNES sdm;
2846: KSP ksp;
2848: PetscFunctionBegin;
2851: PetscCheckSameComm(snes, 1, X, 2);
2852: PetscCall(VecValidValues_Internal(X, 2, PETSC_TRUE));
2853: PetscCall(SNESGetDM(snes, &dm));
2854: PetscCall(DMGetDMSNES(dm, &sdm));
2856: /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix-free */
2857: if (snes->lagjacobian == -2) {
2858: snes->lagjacobian = -1;
2860: PetscCall(PetscInfo(snes, "Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n"));
2861: } else if (snes->lagjacobian == -1) {
2862: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is -1\n"));
2863: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2864: if (flag) {
2865: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2866: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2867: }
2868: PetscFunctionReturn(PETSC_SUCCESS);
2869: } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2870: PetscCall(PetscInfo(snes, "Reusing Jacobian/preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagjacobian, snes->iter));
2871: PetscCall(PetscObjectTypeCompare((PetscObject)A, MATMFFD, &flag));
2872: if (flag) {
2873: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2874: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2875: }
2876: PetscFunctionReturn(PETSC_SUCCESS);
2877: }
2878: if (snes->npc && snes->npcside == PC_LEFT) {
2879: PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
2880: PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));
2881: PetscFunctionReturn(PETSC_SUCCESS);
2882: }
2884: PetscCall(PetscLogEventBegin(SNES_JacobianEval, snes, X, A, B));
2885: PetscCall(VecLockReadPush(X));
2886: {
2887: void *ctx;
2888: SNESJacobianFn *J;
2889: PetscCall(DMSNESGetJacobian(dm, &J, &ctx));
2890: PetscCallBack("SNES callback Jacobian", (*J)(snes, X, A, B, ctx));
2891: }
2892: PetscCall(VecLockReadPop(X));
2893: PetscCall(PetscLogEventEnd(SNES_JacobianEval, snes, X, A, B));
2895: /* attach latest linearization point to the preconditioning matrix */
2896: PetscCall(PetscObjectCompose((PetscObject)B, "__SNES_latest_X", (PetscObject)X));
2898: /* the next line ensures that snes->ksp exists */
2899: PetscCall(SNESGetKSP(snes, &ksp));
2900: if (snes->lagpreconditioner == -2) {
2901: PetscCall(PetscInfo(snes, "Rebuilding preconditioner exactly once since lag is -2\n"));
2902: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2903: snes->lagpreconditioner = -1;
2904: } else if (snes->lagpreconditioner == -1) {
2905: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is -1\n"));
2906: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2907: } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2908: PetscCall(PetscInfo(snes, "Reusing preconditioner because lag is %" PetscInt_FMT " and SNES iteration is %" PetscInt_FMT "\n", snes->lagpreconditioner, snes->iter));
2909: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_TRUE));
2910: } else {
2911: PetscCall(PetscInfo(snes, "Rebuilding preconditioner\n"));
2912: PetscCall(KSPSetReusePreconditioner(snes->ksp, PETSC_FALSE));
2913: }
2915: /* monkey business to allow testing Jacobians in multilevel solvers.
2916: This is needed because the SNESTestXXX interface does not accept vectors and matrices */
2917: {
2918: Vec xsave = snes->vec_sol;
2919: Mat jacobiansave = snes->jacobian;
2920: Mat jacobian_presave = snes->jacobian_pre;
2922: snes->vec_sol = X;
2923: snes->jacobian = A;
2924: snes->jacobian_pre = B;
2925: PetscCall(SNESTestFunction(snes));
2926: PetscCall(SNESTestJacobian(snes));
2928: snes->vec_sol = xsave;
2929: snes->jacobian = jacobiansave;
2930: snes->jacobian_pre = jacobian_presave;
2931: }
2933: {
2934: PetscBool flag = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_operator = PETSC_FALSE;
2935: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit", NULL, NULL, &flag));
2936: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw", NULL, NULL, &flag_draw));
2937: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_explicit_draw_contour", NULL, NULL, &flag_contour));
2938: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_operator", NULL, NULL, &flag_operator));
2939: if (flag || flag_draw || flag_contour) {
2940: Mat Bexp_mine = NULL, Bexp, FDexp;
2941: PetscViewer vdraw, vstdout;
2942: PetscBool flg;
2943: if (flag_operator) {
2944: PetscCall(MatComputeOperator(A, MATAIJ, &Bexp_mine));
2945: Bexp = Bexp_mine;
2946: } else {
2947: /* See if the preconditioning matrix can be viewed and added directly */
2948: PetscCall(PetscObjectBaseTypeCompareAny((PetscObject)B, &flg, MATSEQAIJ, MATMPIAIJ, MATSEQDENSE, MATMPIDENSE, MATSEQBAIJ, MATMPIBAIJ, MATSEQSBAIJ, MATMPIBAIJ, ""));
2949: if (flg) Bexp = B;
2950: else {
2951: /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2952: PetscCall(MatComputeOperator(B, MATAIJ, &Bexp_mine));
2953: Bexp = Bexp_mine;
2954: }
2955: }
2956: PetscCall(MatConvert(Bexp, MATSAME, MAT_INITIAL_MATRIX, &FDexp));
2957: PetscCall(SNESComputeJacobianDefault(snes, X, FDexp, FDexp, NULL));
2958: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
2959: if (flag_draw || flag_contour) {
2960: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Explicit Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
2961: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
2962: } else vdraw = NULL;
2963: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit %s\n", flag_operator ? "Jacobian" : "preconditioning Jacobian"));
2964: if (flag) PetscCall(MatView(Bexp, vstdout));
2965: if (vdraw) PetscCall(MatView(Bexp, vdraw));
2966: PetscCall(PetscViewerASCIIPrintf(vstdout, "Finite difference Jacobian\n"));
2967: if (flag) PetscCall(MatView(FDexp, vstdout));
2968: if (vdraw) PetscCall(MatView(FDexp, vdraw));
2969: PetscCall(MatAYPX(FDexp, -1.0, Bexp, SAME_NONZERO_PATTERN));
2970: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian\n"));
2971: if (flag) PetscCall(MatView(FDexp, vstdout));
2972: if (vdraw) { /* Always use contour for the difference */
2973: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
2974: PetscCall(MatView(FDexp, vdraw));
2975: PetscCall(PetscViewerPopFormat(vdraw));
2976: }
2977: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
2978: PetscCall(PetscViewerDestroy(&vdraw));
2979: PetscCall(MatDestroy(&Bexp_mine));
2980: PetscCall(MatDestroy(&FDexp));
2981: }
2982: }
2983: {
2984: PetscBool flag = PETSC_FALSE, flag_display = PETSC_FALSE, flag_draw = PETSC_FALSE, flag_contour = PETSC_FALSE, flag_threshold = PETSC_FALSE;
2985: PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON, threshold_rtol = 10 * PETSC_SQRT_MACHINE_EPSILON;
2986: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring", NULL, NULL, &flag));
2987: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_display", NULL, NULL, &flag_display));
2988: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw", NULL, NULL, &flag_draw));
2989: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_draw_contour", NULL, NULL, &flag_contour));
2990: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold", NULL, NULL, &flag_threshold));
2991: if (flag_threshold) {
2992: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_rtol", &threshold_rtol, NULL));
2993: PetscCall(PetscOptionsGetReal(((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_compare_coloring_threshold_atol", &threshold_atol, NULL));
2994: }
2995: if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2996: Mat Bfd;
2997: PetscViewer vdraw, vstdout;
2998: MatColoring coloring;
2999: ISColoring iscoloring;
3000: MatFDColoring matfdcoloring;
3001: SNESFunctionFn *func;
3002: void *funcctx;
3003: PetscReal norm1, norm2, normmax;
3005: PetscCall(MatDuplicate(B, MAT_DO_NOT_COPY_VALUES, &Bfd));
3006: PetscCall(MatColoringCreate(Bfd, &coloring));
3007: PetscCall(MatColoringSetType(coloring, MATCOLORINGSL));
3008: PetscCall(MatColoringSetFromOptions(coloring));
3009: PetscCall(MatColoringApply(coloring, &iscoloring));
3010: PetscCall(MatColoringDestroy(&coloring));
3011: PetscCall(MatFDColoringCreate(Bfd, iscoloring, &matfdcoloring));
3012: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3013: PetscCall(MatFDColoringSetUp(Bfd, iscoloring, matfdcoloring));
3014: PetscCall(ISColoringDestroy(&iscoloring));
3016: /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
3017: PetscCall(SNESGetFunction(snes, NULL, &func, &funcctx));
3018: PetscCall(MatFDColoringSetFunction(matfdcoloring, (PetscErrorCode(*)(void))func, funcctx));
3019: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring, ((PetscObject)snes)->prefix));
3020: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring, "coloring_"));
3021: PetscCall(MatFDColoringSetFromOptions(matfdcoloring));
3022: PetscCall(MatFDColoringApply(Bfd, matfdcoloring, X, snes));
3023: PetscCall(MatFDColoringDestroy(&matfdcoloring));
3025: PetscCall(PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes), &vstdout));
3026: if (flag_draw || flag_contour) {
3027: PetscCall(PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes), NULL, "Colored Jacobians", PETSC_DECIDE, PETSC_DECIDE, 300, 300, &vdraw));
3028: if (flag_contour) PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3029: } else vdraw = NULL;
3030: PetscCall(PetscViewerASCIIPrintf(vstdout, "Explicit preconditioning Jacobian\n"));
3031: if (flag_display) PetscCall(MatView(B, vstdout));
3032: if (vdraw) PetscCall(MatView(B, vdraw));
3033: PetscCall(PetscViewerASCIIPrintf(vstdout, "Colored Finite difference Jacobian\n"));
3034: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3035: if (vdraw) PetscCall(MatView(Bfd, vdraw));
3036: PetscCall(MatAYPX(Bfd, -1.0, B, SAME_NONZERO_PATTERN));
3037: PetscCall(MatNorm(Bfd, NORM_1, &norm1));
3038: PetscCall(MatNorm(Bfd, NORM_FROBENIUS, &norm2));
3039: PetscCall(MatNorm(Bfd, NORM_MAX, &normmax));
3040: PetscCall(PetscViewerASCIIPrintf(vstdout, "User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n", (double)norm1, (double)norm2, (double)normmax));
3041: if (flag_display) PetscCall(MatView(Bfd, vstdout));
3042: if (vdraw) { /* Always use contour for the difference */
3043: PetscCall(PetscViewerPushFormat(vdraw, PETSC_VIEWER_DRAW_CONTOUR));
3044: PetscCall(MatView(Bfd, vdraw));
3045: PetscCall(PetscViewerPopFormat(vdraw));
3046: }
3047: if (flag_contour) PetscCall(PetscViewerPopFormat(vdraw));
3049: if (flag_threshold) {
3050: PetscInt bs, rstart, rend, i;
3051: PetscCall(MatGetBlockSize(B, &bs));
3052: PetscCall(MatGetOwnershipRange(B, &rstart, &rend));
3053: for (i = rstart; i < rend; i++) {
3054: const PetscScalar *ba, *ca;
3055: const PetscInt *bj, *cj;
3056: PetscInt bn, cn, j, maxentrycol = -1, maxdiffcol = -1, maxrdiffcol = -1;
3057: PetscReal maxentry = 0, maxdiff = 0, maxrdiff = 0;
3058: PetscCall(MatGetRow(B, i, &bn, &bj, &ba));
3059: PetscCall(MatGetRow(Bfd, i, &cn, &cj, &ca));
3060: PetscCheck(bn == cn, ((PetscObject)A)->comm, PETSC_ERR_PLIB, "Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
3061: for (j = 0; j < bn; j++) {
3062: PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3063: if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
3064: maxentrycol = bj[j];
3065: maxentry = PetscRealPart(ba[j]);
3066: }
3067: if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
3068: maxdiffcol = bj[j];
3069: maxdiff = PetscRealPart(ca[j]);
3070: }
3071: if (rdiff > maxrdiff) {
3072: maxrdiffcol = bj[j];
3073: maxrdiff = rdiff;
3074: }
3075: }
3076: if (maxrdiff > 1) {
3077: 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));
3078: for (j = 0; j < bn; j++) {
3079: PetscReal rdiff;
3080: rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol * PetscAbsScalar(ba[j]));
3081: if (rdiff > 1) PetscCall(PetscViewerASCIIPrintf(vstdout, " (%" PetscInt_FMT ",%g:%g)", bj[j], (double)PetscRealPart(ba[j]), (double)PetscRealPart(ca[j])));
3082: }
3083: PetscCall(PetscViewerASCIIPrintf(vstdout, "\n"));
3084: }
3085: PetscCall(MatRestoreRow(B, i, &bn, &bj, &ba));
3086: PetscCall(MatRestoreRow(Bfd, i, &cn, &cj, &ca));
3087: }
3088: }
3089: PetscCall(PetscViewerDestroy(&vdraw));
3090: PetscCall(MatDestroy(&Bfd));
3091: }
3092: }
3093: PetscFunctionReturn(PETSC_SUCCESS);
3094: }
3096: /*@C
3097: SNESSetJacobian - Sets the function to compute Jacobian as well as the
3098: location to store the matrix.
3100: Logically Collective
3102: Input Parameters:
3103: + snes - the `SNES` context
3104: . Amat - the matrix that defines the (approximate) Jacobian
3105: . Pmat - the matrix to be used in constructing the preconditioner, usually the same as `Amat`.
3106: . J - Jacobian evaluation routine (if `NULL` then `SNES` retains any previously set value), see `SNESJacobianFn` for details
3107: - ctx - [optional] user-defined context for private data for the
3108: Jacobian evaluation routine (may be `NULL`) (if `NULL` then `SNES` retains any previously set value)
3110: Level: beginner
3112: Notes:
3113: If the `Amat` matrix and `Pmat` matrix are different you must call `MatAssemblyBegin()`/`MatAssemblyEnd()` on
3114: each matrix.
3116: If you know the operator `Amat` has a null space you can use `MatSetNullSpace()` and `MatSetTransposeNullSpace()` to supply the null
3117: space to `Amat` and the `KSP` solvers will automatically use that null space as needed during the solution process.
3119: If using `SNESComputeJacobianDefaultColor()` to assemble a Jacobian, the `ctx` argument
3120: must be a `MatFDColoring`.
3122: Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian. One common
3123: example is to use the "Picard linearization" which only differentiates through the highest order parts of each term using `SNESSetPicard()`
3125: .seealso: [](ch_snes), `SNES`, `KSPSetOperators()`, `SNESSetFunction()`, `MatMFFDComputeJacobian()`, `SNESComputeJacobianDefaultColor()`, `MatStructure`,
3126: `SNESSetPicard()`, `SNESJacobianFn`, `SNESFunctionFn`
3127: @*/
3128: PetscErrorCode SNESSetJacobian(SNES snes, Mat Amat, Mat Pmat, SNESJacobianFn *J, void *ctx)
3129: {
3130: DM dm;
3132: PetscFunctionBegin;
3136: if (Amat) PetscCheckSameComm(snes, 1, Amat, 2);
3137: if (Pmat) PetscCheckSameComm(snes, 1, Pmat, 3);
3138: PetscCall(SNESGetDM(snes, &dm));
3139: PetscCall(DMSNESSetJacobian(dm, J, ctx));
3140: if (Amat) {
3141: PetscCall(PetscObjectReference((PetscObject)Amat));
3142: PetscCall(MatDestroy(&snes->jacobian));
3144: snes->jacobian = Amat;
3145: }
3146: if (Pmat) {
3147: PetscCall(PetscObjectReference((PetscObject)Pmat));
3148: PetscCall(MatDestroy(&snes->jacobian_pre));
3150: snes->jacobian_pre = Pmat;
3151: }
3152: PetscFunctionReturn(PETSC_SUCCESS);
3153: }
3155: /*@C
3156: SNESGetJacobian - Returns the Jacobian matrix and optionally the user
3157: provided context for evaluating the Jacobian.
3159: Not Collective, but `Mat` object will be parallel if `SNES` is
3161: Input Parameter:
3162: . snes - the nonlinear solver context
3164: Output Parameters:
3165: + Amat - location to stash (approximate) Jacobian matrix (or `NULL`)
3166: . Pmat - location to stash matrix used to compute the preconditioner (or `NULL`)
3167: . J - location to put Jacobian function (or `NULL`), for calling sequence see `SNESJacobianFn`
3168: - ctx - location to stash Jacobian ctx (or `NULL`)
3170: Level: advanced
3172: .seealso: [](ch_snes), `SNES`, `Mat`, `SNESSetJacobian()`, `SNESComputeJacobian()`, `SNESJacobianFn`, `SNESGetFunction()`
3173: @*/
3174: PetscErrorCode SNESGetJacobian(SNES snes, Mat *Amat, Mat *Pmat, SNESJacobianFn **J, void **ctx)
3175: {
3176: DM dm;
3178: PetscFunctionBegin;
3180: if (Amat) *Amat = snes->jacobian;
3181: if (Pmat) *Pmat = snes->jacobian_pre;
3182: PetscCall(SNESGetDM(snes, &dm));
3183: PetscCall(DMSNESGetJacobian(dm, J, ctx));
3184: PetscFunctionReturn(PETSC_SUCCESS);
3185: }
3187: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3188: {
3189: DM dm;
3190: DMSNES sdm;
3192: PetscFunctionBegin;
3193: PetscCall(SNESGetDM(snes, &dm));
3194: PetscCall(DMGetDMSNES(dm, &sdm));
3195: if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3196: DM dm;
3197: PetscBool isdense, ismf;
3199: PetscCall(SNESGetDM(snes, &dm));
3200: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &isdense, MATSEQDENSE, MATMPIDENSE, MATDENSE, NULL));
3201: PetscCall(PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre, &ismf, MATMFFD, MATSHELL, NULL));
3202: if (isdense) {
3203: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefault, NULL));
3204: } else if (!ismf) {
3205: PetscCall(DMSNESSetJacobian(dm, SNESComputeJacobianDefaultColor, NULL));
3206: }
3207: }
3208: PetscFunctionReturn(PETSC_SUCCESS);
3209: }
3211: /*@
3212: SNESSetUp - Sets up the internal data structures for the later use
3213: of a nonlinear solver.
3215: Collective
3217: Input Parameter:
3218: . snes - the `SNES` context
3220: Level: advanced
3222: Note:
3223: For basic use of the `SNES` solvers the user need not explicitly call
3224: `SNESSetUp()`, since these actions will automatically occur during
3225: the call to `SNESSolve()`. However, if one wishes to control this
3226: phase separately, `SNESSetUp()` should be called after `SNESCreate()`
3227: and optional routines of the form SNESSetXXX(), but before `SNESSolve()`.
3229: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`, `SNESDestroy()`
3230: @*/
3231: PetscErrorCode SNESSetUp(SNES snes)
3232: {
3233: DM dm;
3234: DMSNES sdm;
3235: SNESLineSearch linesearch, pclinesearch;
3236: void *lsprectx, *lspostctx;
3237: PetscBool mf_operator, mf;
3238: Vec f, fpc;
3239: void *funcctx;
3240: void *jacctx, *appctx;
3241: Mat j, jpre;
3242: PetscErrorCode (*precheck)(SNESLineSearch, Vec, Vec, PetscBool *, void *);
3243: PetscErrorCode (*postcheck)(SNESLineSearch, Vec, Vec, Vec, PetscBool *, PetscBool *, void *);
3244: SNESFunctionFn *func;
3245: SNESJacobianFn *jac;
3247: PetscFunctionBegin;
3249: if (snes->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
3250: PetscCall(PetscLogEventBegin(SNES_SetUp, snes, 0, 0, 0));
3252: if (!((PetscObject)snes)->type_name) PetscCall(SNESSetType(snes, SNESNEWTONLS));
3254: PetscCall(SNESGetFunction(snes, &snes->vec_func, NULL, NULL));
3256: PetscCall(SNESGetDM(snes, &dm));
3257: PetscCall(DMGetDMSNES(dm, &sdm));
3258: PetscCall(SNESSetDefaultComputeJacobian(snes));
3260: if (!snes->vec_func) PetscCall(DMCreateGlobalVector(dm, &snes->vec_func));
3262: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
3264: if (snes->linesearch) {
3265: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
3266: PetscCall(SNESLineSearchSetFunction(snes->linesearch, SNESComputeFunction));
3267: }
3269: PetscCall(SNESGetUseMatrixFree(snes, &mf_operator, &mf));
3270: if (snes->npc && snes->npcside == PC_LEFT) {
3271: snes->mf = PETSC_TRUE;
3272: snes->mf_operator = PETSC_FALSE;
3273: }
3275: if (snes->npc) {
3276: /* copy the DM over */
3277: PetscCall(SNESGetDM(snes, &dm));
3278: PetscCall(SNESSetDM(snes->npc, dm));
3280: PetscCall(SNESGetFunction(snes, &f, &func, &funcctx));
3281: PetscCall(VecDuplicate(f, &fpc));
3282: PetscCall(SNESSetFunction(snes->npc, fpc, func, funcctx));
3283: PetscCall(SNESGetJacobian(snes, &j, &jpre, &jac, &jacctx));
3284: PetscCall(SNESSetJacobian(snes->npc, j, jpre, jac, jacctx));
3285: PetscCall(SNESGetApplicationContext(snes, &appctx));
3286: PetscCall(SNESSetApplicationContext(snes->npc, appctx));
3287: PetscCall(SNESSetUseMatrixFree(snes->npc, mf_operator, mf));
3288: PetscCall(VecDestroy(&fpc));
3290: /* copy the function pointers over */
3291: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)snes, (PetscObject)snes->npc));
3293: /* default to 1 iteration */
3294: PetscCall(SNESSetTolerances(snes->npc, 0.0, 0.0, 0.0, 1, snes->npc->max_funcs));
3295: if (snes->npcside == PC_RIGHT) {
3296: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_FINAL_ONLY));
3297: } else {
3298: PetscCall(SNESSetNormSchedule(snes->npc, SNES_NORM_NONE));
3299: }
3300: PetscCall(SNESSetFromOptions(snes->npc));
3302: /* copy the line search context over */
3303: if (snes->linesearch && snes->npc->linesearch) {
3304: PetscCall(SNESGetLineSearch(snes, &linesearch));
3305: PetscCall(SNESGetLineSearch(snes->npc, &pclinesearch));
3306: PetscCall(SNESLineSearchGetPreCheck(linesearch, &precheck, &lsprectx));
3307: PetscCall(SNESLineSearchGetPostCheck(linesearch, &postcheck, &lspostctx));
3308: PetscCall(SNESLineSearchSetPreCheck(pclinesearch, precheck, lsprectx));
3309: PetscCall(SNESLineSearchSetPostCheck(pclinesearch, postcheck, lspostctx));
3310: PetscCall(PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch));
3311: }
3312: }
3313: if (snes->mf) PetscCall(SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version));
3314: if (snes->ops->usercompute && !snes->user) PetscCallBack("SNES callback compute application context", (*snes->ops->usercompute)(snes, (void **)&snes->user));
3316: snes->jac_iter = 0;
3317: snes->pre_iter = 0;
3319: PetscTryTypeMethod(snes, setup);
3321: PetscCall(SNESSetDefaultComputeJacobian(snes));
3323: if (snes->npc && snes->npcside == PC_LEFT) {
3324: if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3325: if (snes->linesearch) {
3326: PetscCall(SNESGetLineSearch(snes, &linesearch));
3327: PetscCall(SNESLineSearchSetFunction(linesearch, SNESComputeFunctionDefaultNPC));
3328: }
3329: }
3330: }
3331: PetscCall(PetscLogEventEnd(SNES_SetUp, snes, 0, 0, 0));
3332: snes->setupcalled = PETSC_TRUE;
3333: PetscFunctionReturn(PETSC_SUCCESS);
3334: }
3336: /*@
3337: SNESReset - Resets a `SNES` context to the snessetupcalled = 0 state and removes any allocated `Vec`s and `Mat`s
3339: Collective
3341: Input Parameter:
3342: . snes - iterative context obtained from `SNESCreate()`
3344: Level: intermediate
3346: Notes:
3347: Call this if you wish to reuse a `SNES` but with different size vectors
3349: Also calls the application context destroy routine set with `SNESSetComputeApplicationContext()`
3351: .seealso: [](ch_snes), `SNES`, `SNESDestroy()`, `SNESCreate()`, `SNESSetUp()`, `SNESSolve()`
3352: @*/
3353: PetscErrorCode SNESReset(SNES snes)
3354: {
3355: PetscFunctionBegin;
3357: if (snes->ops->userdestroy && snes->user) {
3358: PetscCallBack("SNES callback destroy application context", (*snes->ops->userdestroy)((void **)&snes->user));
3359: snes->user = NULL;
3360: }
3361: if (snes->npc) PetscCall(SNESReset(snes->npc));
3363: PetscTryTypeMethod(snes, reset);
3364: if (snes->ksp) PetscCall(KSPReset(snes->ksp));
3366: if (snes->linesearch) PetscCall(SNESLineSearchReset(snes->linesearch));
3368: PetscCall(VecDestroy(&snes->vec_rhs));
3369: PetscCall(VecDestroy(&snes->vec_sol));
3370: PetscCall(VecDestroy(&snes->vec_sol_update));
3371: PetscCall(VecDestroy(&snes->vec_func));
3372: PetscCall(MatDestroy(&snes->jacobian));
3373: PetscCall(MatDestroy(&snes->jacobian_pre));
3374: PetscCall(MatDestroy(&snes->picard));
3375: PetscCall(VecDestroyVecs(snes->nwork, &snes->work));
3376: PetscCall(VecDestroyVecs(snes->nvwork, &snes->vwork));
3378: snes->alwayscomputesfinalresidual = PETSC_FALSE;
3380: snes->nwork = snes->nvwork = 0;
3381: snes->setupcalled = PETSC_FALSE;
3382: PetscFunctionReturn(PETSC_SUCCESS);
3383: }
3385: /*@
3386: SNESConvergedReasonViewCancel - Clears all the reason view functions for a `SNES` object provided with `SNESConvergedReasonViewSet()`
3388: Collective
3390: Input Parameter:
3391: . snes - iterative context obtained from `SNESCreate()`
3393: Level: intermediate
3395: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESReset()`, `SNESConvergedReasonViewSet()`
3396: @*/
3397: PetscErrorCode SNESConvergedReasonViewCancel(SNES snes)
3398: {
3399: PetscInt i;
3401: PetscFunctionBegin;
3403: for (i = 0; i < snes->numberreasonviews; i++) {
3404: if (snes->reasonviewdestroy[i]) PetscCall((*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]));
3405: }
3406: snes->numberreasonviews = 0;
3407: PetscFunctionReturn(PETSC_SUCCESS);
3408: }
3410: /*@C
3411: SNESDestroy - Destroys the nonlinear solver context that was created
3412: with `SNESCreate()`.
3414: Collective
3416: Input Parameter:
3417: . snes - the `SNES` context
3419: Level: beginner
3421: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESSolve()`
3422: @*/
3423: PetscErrorCode SNESDestroy(SNES *snes)
3424: {
3425: PetscFunctionBegin;
3426: if (!*snes) PetscFunctionReturn(PETSC_SUCCESS);
3428: if (--((PetscObject)*snes)->refct > 0) {
3429: *snes = NULL;
3430: PetscFunctionReturn(PETSC_SUCCESS);
3431: }
3433: PetscCall(SNESReset(*snes));
3434: PetscCall(SNESDestroy(&(*snes)->npc));
3436: /* if memory was published with SAWs then destroy it */
3437: PetscCall(PetscObjectSAWsViewOff((PetscObject)*snes));
3438: PetscTryTypeMethod(*snes, destroy);
3440: if ((*snes)->dm) PetscCall(DMCoarsenHookRemove((*snes)->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, *snes));
3441: PetscCall(DMDestroy(&(*snes)->dm));
3442: PetscCall(KSPDestroy(&(*snes)->ksp));
3443: PetscCall(SNESLineSearchDestroy(&(*snes)->linesearch));
3445: PetscCall(PetscFree((*snes)->kspconvctx));
3446: if ((*snes)->ops->convergeddestroy) PetscCall((*(*snes)->ops->convergeddestroy)((*snes)->cnvP));
3447: if ((*snes)->conv_hist_alloc) PetscCall(PetscFree2((*snes)->conv_hist, (*snes)->conv_hist_its));
3448: PetscCall(SNESMonitorCancel(*snes));
3449: PetscCall(SNESConvergedReasonViewCancel(*snes));
3450: PetscCall(PetscHeaderDestroy(snes));
3451: PetscFunctionReturn(PETSC_SUCCESS);
3452: }
3454: /* ----------- Routines to set solver parameters ---------- */
3456: /*@
3457: SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.
3459: Logically Collective
3461: Input Parameters:
3462: + snes - the `SNES` context
3463: - lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3464: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3466: Options Database Keys:
3467: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3468: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3469: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple `SNESSolve()`
3470: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3472: Level: intermediate
3474: Notes:
3475: The default is 1
3477: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagPreconditionerPersists()` was called
3479: `SNESSetLagPreconditionerPersists()` allows using the same uniform lagging (for example every second linear solve) across multiple nonlinear solves.
3481: .seealso: [](ch_snes), `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetLagPreconditionerPersists()`,
3482: `SNESSetLagJacobianPersists()`, `SNES`, `SNESSolve()`
3483: @*/
3484: PetscErrorCode SNESSetLagPreconditioner(SNES snes, PetscInt lag)
3485: {
3486: PetscFunctionBegin;
3488: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3489: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3491: snes->lagpreconditioner = lag;
3492: PetscFunctionReturn(PETSC_SUCCESS);
3493: }
3495: /*@
3496: SNESSetGridSequence - sets the number of steps of grid sequencing that `SNES` will do
3498: Logically Collective
3500: Input Parameters:
3501: + snes - the `SNES` context
3502: - steps - the number of refinements to do, defaults to 0
3504: Options Database Key:
3505: . -snes_grid_sequence <steps> - Use grid sequencing to generate initial guess
3507: Level: intermediate
3509: Note:
3510: Use `SNESGetSolution()` to extract the fine grid solution after grid sequencing.
3512: .seealso: [](ch_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetGridSequence()`,
3513: `SNESetDM()`
3514: @*/
3515: PetscErrorCode SNESSetGridSequence(SNES snes, PetscInt steps)
3516: {
3517: PetscFunctionBegin;
3520: snes->gridsequence = steps;
3521: PetscFunctionReturn(PETSC_SUCCESS);
3522: }
3524: /*@
3525: SNESGetGridSequence - gets the number of steps of grid sequencing that `SNES` will do
3527: Logically Collective
3529: Input Parameter:
3530: . snes - the `SNES` context
3532: Output Parameter:
3533: . steps - the number of refinements to do, defaults to 0
3535: Level: intermediate
3537: .seealso: [](ch_snes), `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESSetGridSequence()`
3538: @*/
3539: PetscErrorCode SNESGetGridSequence(SNES snes, PetscInt *steps)
3540: {
3541: PetscFunctionBegin;
3543: *steps = snes->gridsequence;
3544: PetscFunctionReturn(PETSC_SUCCESS);
3545: }
3547: /*@
3548: SNESGetLagPreconditioner - Return how often the preconditioner is rebuilt
3550: Not Collective
3552: Input Parameter:
3553: . snes - the `SNES` context
3555: Output Parameter:
3556: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3557: the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that
3559: Level: intermediate
3561: Notes:
3562: The default is 1
3564: The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3566: .seealso: [](ch_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESSetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3567: @*/
3568: PetscErrorCode SNESGetLagPreconditioner(SNES snes, PetscInt *lag)
3569: {
3570: PetscFunctionBegin;
3572: *lag = snes->lagpreconditioner;
3573: PetscFunctionReturn(PETSC_SUCCESS);
3574: }
3576: /*@
3577: SNESSetLagJacobian - Set when the Jacobian is rebuilt in the nonlinear solve. See `SNESSetLagPreconditioner()` for determining how
3578: often the preconditioner is rebuilt.
3580: Logically Collective
3582: Input Parameters:
3583: + snes - the `SNES` context
3584: - lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3585: the Jacobian is built etc. -2 means rebuild at next chance but then never again
3587: Options Database Keys:
3588: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3589: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3590: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3591: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag.
3593: Level: intermediate
3595: Notes:
3596: The default is 1
3598: The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3600: 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
3601: at the next Newton step but never again (unless it is reset to another value)
3603: .seealso: [](ch_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESGetLagPreconditioner()`, `SNESSetLagPreconditioner()`, `SNESGetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3604: @*/
3605: PetscErrorCode SNESSetLagJacobian(SNES snes, PetscInt lag)
3606: {
3607: PetscFunctionBegin;
3609: PetscCheck(lag >= -2, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag must be -2, -1, 1 or greater");
3610: PetscCheck(lag, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Lag cannot be 0");
3612: snes->lagjacobian = lag;
3613: PetscFunctionReturn(PETSC_SUCCESS);
3614: }
3616: /*@
3617: SNESGetLagJacobian - Get how often the Jacobian is rebuilt. See `SNESGetLagPreconditioner()` to determine when the preconditioner is rebuilt
3619: Not Collective
3621: Input Parameter:
3622: . snes - the `SNES` context
3624: Output Parameter:
3625: . lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3626: the Jacobian is built etc.
3628: Level: intermediate
3630: Notes:
3631: The default is 1
3633: The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or `SNESSetLagJacobianPersists()` was called.
3635: .seealso: [](ch_snes), `SNES`, `SNESSetTrustRegionTolerance()`, `SNESSetLagJacobian()`, `SNESSetLagPreconditioner()`, `SNESGetLagPreconditioner()`, `SNESSetLagJacobianPersists()`, `SNESSetLagPreconditionerPersists()`
3637: @*/
3638: PetscErrorCode SNESGetLagJacobian(SNES snes, PetscInt *lag)
3639: {
3640: PetscFunctionBegin;
3642: *lag = snes->lagjacobian;
3643: PetscFunctionReturn(PETSC_SUCCESS);
3644: }
3646: /*@
3647: SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple nonlinear solves
3649: Logically collective
3651: Input Parameters:
3652: + snes - the `SNES` context
3653: - flg - jacobian lagging persists if true
3655: Options Database Keys:
3656: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3657: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3658: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3659: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3661: Level: advanced
3663: Notes:
3664: Normally when `SNESSetLagJacobian()` is used, the Jacobian is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3666: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3667: several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3668: timesteps may present huge efficiency gains.
3670: .seealso: [](ch_snes), `SNES`, `SNESSetLagPreconditionerPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`
3671: @*/
3672: PetscErrorCode SNESSetLagJacobianPersists(SNES snes, PetscBool flg)
3673: {
3674: PetscFunctionBegin;
3677: snes->lagjac_persist = flg;
3678: PetscFunctionReturn(PETSC_SUCCESS);
3679: }
3681: /*@
3682: SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves
3684: Logically Collective
3686: Input Parameters:
3687: + snes - the `SNES` context
3688: - flg - preconditioner lagging persists if true
3690: Options Database Keys:
3691: + -snes_lag_jacobian_persists <true,false> - sets the persistence through multiple SNES solves
3692: . -snes_lag_jacobian <-2,1,2,...> - sets the lag
3693: . -snes_lag_preconditioner_persists <true,false> - sets the persistence through multiple SNES solves
3694: - -snes_lag_preconditioner <-2,1,2,...> - sets the lag
3696: Level: developer
3698: Notes:
3699: Normally when `SNESSetLagPreconditioner()` is used, the preconditioner is always rebuilt at the beginning of each new nonlinear solve, this removes that behavior
3701: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3702: by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3703: several timesteps may present huge efficiency gains.
3705: .seealso: [](ch_snes), `SNES`, `SNESSetLagJacobianPersists()`, `SNESSetLagJacobian()`, `SNESGetLagJacobian()`, `SNESGetNPC()`, `SNESSetLagPreconditioner()`
3706: @*/
3707: PetscErrorCode SNESSetLagPreconditionerPersists(SNES snes, PetscBool flg)
3708: {
3709: PetscFunctionBegin;
3712: snes->lagpre_persist = flg;
3713: PetscFunctionReturn(PETSC_SUCCESS);
3714: }
3716: /*@
3717: SNESSetForceIteration - force `SNESSolve()` to take at least one iteration regardless of the initial residual norm
3719: Logically Collective
3721: Input Parameters:
3722: + snes - the `SNES` context
3723: - force - `PETSC_TRUE` require at least one iteration
3725: Options Database Key:
3726: . -snes_force_iteration <force> - Sets forcing an iteration
3728: Level: intermediate
3730: Note:
3731: This is used sometimes with `TS` to prevent `TS` from detecting a false steady state solution
3733: .seealso: [](ch_snes), `SNES`, `TS`, `SNESSetTrustRegionTolerance()`, `SNESSetDivergenceTolerance()`
3734: @*/
3735: PetscErrorCode SNESSetForceIteration(SNES snes, PetscBool force)
3736: {
3737: PetscFunctionBegin;
3739: snes->forceiteration = force;
3740: PetscFunctionReturn(PETSC_SUCCESS);
3741: }
3743: /*@
3744: SNESGetForceIteration - Check whether or not `SNESSolve()` take at least one iteration regardless of the initial residual norm
3746: Logically Collective
3748: Input Parameter:
3749: . snes - the `SNES` context
3751: Output Parameter:
3752: . force - `PETSC_TRUE` requires at least one iteration.
3754: Level: intermediate
3756: .seealso: [](ch_snes), `SNES`, `SNESSetForceIteration()`, `SNESSetTrustRegionTolerance()`, `SNESSetDivergenceTolerance()`
3757: @*/
3758: PetscErrorCode SNESGetForceIteration(SNES snes, PetscBool *force)
3759: {
3760: PetscFunctionBegin;
3762: *force = snes->forceiteration;
3763: PetscFunctionReturn(PETSC_SUCCESS);
3764: }
3766: /*@
3767: SNESSetTolerances - Sets `SNES` various parameters used in convergence tests.
3769: Logically Collective
3771: Input Parameters:
3772: + snes - the `SNES` context
3773: . abstol - absolute convergence tolerance
3774: . rtol - relative convergence tolerance
3775: . stol - convergence tolerance in terms of the norm of the change in the solution between steps, || delta x || < stol*|| x ||
3776: . maxit - maximum number of iterations, default 50.
3777: - maxf - maximum number of function evaluations (-1 indicates no limit), default 1000
3779: Options Database Keys:
3780: + -snes_atol <abstol> - Sets abstol
3781: . -snes_rtol <rtol> - Sets rtol
3782: . -snes_stol <stol> - Sets stol
3783: . -snes_max_it <maxit> - Sets maxit
3784: - -snes_max_funcs <maxf> - Sets maxf
3786: Level: intermediate
3788: .seealso: [](ch_snes), `SNESSolve()`, `SNES`, `SNESSetTrustRegionTolerance()`, `SNESSetDivergenceTolerance()`, `SNESSetForceIteration()`
3789: @*/
3790: PetscErrorCode SNESSetTolerances(SNES snes, PetscReal abstol, PetscReal rtol, PetscReal stol, PetscInt maxit, PetscInt maxf)
3791: {
3792: PetscFunctionBegin;
3800: if (abstol != (PetscReal)PETSC_DEFAULT) {
3801: PetscCheck(abstol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Absolute tolerance %g must be non-negative", (double)abstol);
3802: snes->abstol = abstol;
3803: }
3804: if (rtol != (PetscReal)PETSC_DEFAULT) {
3805: 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);
3806: snes->rtol = rtol;
3807: }
3808: if (stol != (PetscReal)PETSC_DEFAULT) {
3809: PetscCheck(stol >= 0.0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Step tolerance %g must be non-negative", (double)stol);
3810: snes->stol = stol;
3811: }
3812: if (maxit != PETSC_DEFAULT) {
3813: PetscCheck(maxit >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of iterations %" PetscInt_FMT " must be non-negative", maxit);
3814: snes->max_its = maxit;
3815: }
3816: if (maxf != PETSC_DEFAULT) {
3817: PetscCheck(maxf >= -1, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_OUTOFRANGE, "Maximum number of function evaluations %" PetscInt_FMT " must be -1 or nonnegative", maxf);
3818: snes->max_funcs = maxf;
3819: }
3820: snes->tolerancesset = PETSC_TRUE;
3821: PetscFunctionReturn(PETSC_SUCCESS);
3822: }
3824: /*@
3825: SNESSetDivergenceTolerance - Sets the divergence tolerance used for the `SNES` divergence test.
3827: Logically Collective
3829: Input Parameters:
3830: + snes - the `SNES` context
3831: - divtol - the divergence tolerance.
3833: Options Database Key:
3834: . -snes_divergence_tolerance <divtol> - Sets `divtol`
3836: Level: intermediate
3838: Note:
3839: Non-positive values of `divtol` different from `PETSC_DEFAULT` will deactivate the test.
3841: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetTolerances()`, `SNESGetDivergenceTolerance`
3842: @*/
3843: PetscErrorCode SNESSetDivergenceTolerance(SNES snes, PetscReal divtol)
3844: {
3845: PetscFunctionBegin;
3848: if (divtol != (PetscReal)PETSC_DEFAULT) snes->divtol = divtol;
3849: PetscFunctionReturn(PETSC_SUCCESS);
3850: }
3852: /*@
3853: SNESGetTolerances - Gets various parameters used in convergence tests.
3855: Not Collective
3857: Input Parameters:
3858: + snes - the `SNES` context
3859: . atol - absolute convergence tolerance
3860: . rtol - relative convergence tolerance
3861: . stol - convergence tolerance in terms of the norm
3862: of the change in the solution between steps
3863: . maxit - maximum number of iterations
3864: - maxf - maximum number of function evaluations
3866: Level: intermediate
3868: Note:
3869: The user can specify `NULL` for any parameter that is not needed.
3871: .seealso: [](ch_snes), `SNES`, `SNESSetTolerances()`
3872: @*/
3873: PetscErrorCode SNESGetTolerances(SNES snes, PetscReal *atol, PetscReal *rtol, PetscReal *stol, PetscInt *maxit, PetscInt *maxf)
3874: {
3875: PetscFunctionBegin;
3877: if (atol) *atol = snes->abstol;
3878: if (rtol) *rtol = snes->rtol;
3879: if (stol) *stol = snes->stol;
3880: if (maxit) *maxit = snes->max_its;
3881: if (maxf) *maxf = snes->max_funcs;
3882: PetscFunctionReturn(PETSC_SUCCESS);
3883: }
3885: /*@
3886: SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.
3888: Not Collective
3890: Input Parameters:
3891: + snes - the `SNES` context
3892: - divtol - divergence tolerance
3894: Level: intermediate
3896: .seealso: [](ch_snes), `SNES`, `SNESSetDivergenceTolerance()`
3897: @*/
3898: PetscErrorCode SNESGetDivergenceTolerance(SNES snes, PetscReal *divtol)
3899: {
3900: PetscFunctionBegin;
3902: if (divtol) *divtol = snes->divtol;
3903: PetscFunctionReturn(PETSC_SUCCESS);
3904: }
3906: /*@
3907: SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.
3909: Logically Collective
3911: Input Parameters:
3912: + snes - the `SNES` context
3913: - tol - tolerance
3915: Options Database Key:
3916: . -snes_tr_tol <tol> - Sets tol
3918: Level: intermediate
3920: Developer Note:
3921: Should be SNESTrustRegionSetTolerance()
3923: .seealso: [](ch_snes), `SNES`, `SNESNEWTONTR`, `SNESSetTolerances()`
3924: @*/
3925: PetscErrorCode SNESSetTrustRegionTolerance(SNES snes, PetscReal tol)
3926: {
3927: PetscFunctionBegin;
3930: snes->deltatol = tol;
3931: PetscFunctionReturn(PETSC_SUCCESS);
3932: }
3934: PETSC_INTERN PetscErrorCode SNESMonitorRange_Private(SNES, PetscInt, PetscReal *);
3936: PetscErrorCode SNESMonitorLGRange(SNES snes, PetscInt n, PetscReal rnorm, void *monctx)
3937: {
3938: PetscDrawLG lg;
3939: PetscReal x, y, per;
3940: PetscViewer v = (PetscViewer)monctx;
3941: static PetscReal prev; /* should be in the context */
3942: PetscDraw draw;
3944: PetscFunctionBegin;
3946: PetscCall(PetscViewerDrawGetDrawLG(v, 0, &lg));
3947: if (!n) PetscCall(PetscDrawLGReset(lg));
3948: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3949: PetscCall(PetscDrawSetTitle(draw, "Residual norm"));
3950: x = (PetscReal)n;
3951: if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3952: else y = -15.0;
3953: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3954: if (n < 20 || !(n % 5) || snes->reason) {
3955: PetscCall(PetscDrawLGDraw(lg));
3956: PetscCall(PetscDrawLGSave(lg));
3957: }
3959: PetscCall(PetscViewerDrawGetDrawLG(v, 1, &lg));
3960: if (!n) PetscCall(PetscDrawLGReset(lg));
3961: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3962: PetscCall(PetscDrawSetTitle(draw, "% elements > .2*max element"));
3963: PetscCall(SNESMonitorRange_Private(snes, n, &per));
3964: x = (PetscReal)n;
3965: y = 100.0 * per;
3966: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3967: if (n < 20 || !(n % 5) || snes->reason) {
3968: PetscCall(PetscDrawLGDraw(lg));
3969: PetscCall(PetscDrawLGSave(lg));
3970: }
3972: PetscCall(PetscViewerDrawGetDrawLG(v, 2, &lg));
3973: if (!n) {
3974: prev = rnorm;
3975: PetscCall(PetscDrawLGReset(lg));
3976: }
3977: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3978: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm"));
3979: x = (PetscReal)n;
3980: y = (prev - rnorm) / prev;
3981: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3982: if (n < 20 || !(n % 5) || snes->reason) {
3983: PetscCall(PetscDrawLGDraw(lg));
3984: PetscCall(PetscDrawLGSave(lg));
3985: }
3987: PetscCall(PetscViewerDrawGetDrawLG(v, 3, &lg));
3988: if (!n) PetscCall(PetscDrawLGReset(lg));
3989: PetscCall(PetscDrawLGGetDraw(lg, &draw));
3990: PetscCall(PetscDrawSetTitle(draw, "(norm -oldnorm)/oldnorm*(% > .2 max)"));
3991: x = (PetscReal)n;
3992: y = (prev - rnorm) / (prev * per);
3993: if (n > 2) { /*skip initial crazy value */
3994: PetscCall(PetscDrawLGAddPoint(lg, &x, &y));
3995: }
3996: if (n < 20 || !(n % 5) || snes->reason) {
3997: PetscCall(PetscDrawLGDraw(lg));
3998: PetscCall(PetscDrawLGSave(lg));
3999: }
4000: prev = rnorm;
4001: PetscFunctionReturn(PETSC_SUCCESS);
4002: }
4004: /*@
4005: SNESConverged - Run the convergence test and update the `SNESConvergedReason`.
4007: Collective
4009: Input Parameters:
4010: + snes - the `SNES` context
4011: . it - current iteration
4012: . xnorm - 2-norm of current iterate
4013: . snorm - 2-norm of current step
4014: - fnorm - 2-norm of function
4016: Level: developer
4018: Note:
4019: This routine is called by the `SNESSolve()` implementations.
4020: It does not typically need to be called by the user.
4022: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`, `SNESGetConvergenceTest()`
4023: @*/
4024: PetscErrorCode SNESConverged(SNES snes, PetscInt it, PetscReal xnorm, PetscReal snorm, PetscReal fnorm)
4025: {
4026: PetscFunctionBegin;
4027: if (!snes->reason) {
4028: if (snes->normschedule == SNES_NORM_ALWAYS) PetscUseTypeMethod(snes, converged, it, xnorm, snorm, fnorm, &snes->reason, snes->cnvP);
4029: if (it == snes->max_its && !snes->reason) {
4030: if (snes->normschedule == SNES_NORM_ALWAYS) {
4031: PetscCall(PetscInfo(snes, "Maximum number of iterations has been reached: %" PetscInt_FMT "\n", snes->max_its));
4032: snes->reason = SNES_DIVERGED_MAX_IT;
4033: } else snes->reason = SNES_CONVERGED_ITS;
4034: }
4035: }
4036: PetscFunctionReturn(PETSC_SUCCESS);
4037: }
4039: /*@
4040: SNESMonitor - runs the user provided monitor routines, if they exist
4042: Collective
4044: Input Parameters:
4045: + snes - nonlinear solver context obtained from `SNESCreate()`
4046: . iter - iteration number
4047: - rnorm - relative norm of the residual
4049: Level: developer
4051: Note:
4052: This routine is called by the `SNESSolve()` implementations.
4053: It does not typically need to be called by the user.
4055: .seealso: [](ch_snes), `SNES`, `SNESMonitorSet()`
4056: @*/
4057: PetscErrorCode SNESMonitor(SNES snes, PetscInt iter, PetscReal rnorm)
4058: {
4059: PetscInt i, n = snes->numbermonitors;
4061: PetscFunctionBegin;
4062: if (n > 0) SNESCheckFunctionNorm(snes, rnorm);
4063: PetscCall(VecLockReadPush(snes->vec_sol));
4064: for (i = 0; i < n; i++) PetscCall((*snes->monitor[i])(snes, iter, rnorm, snes->monitorcontext[i]));
4065: PetscCall(VecLockReadPop(snes->vec_sol));
4066: PetscFunctionReturn(PETSC_SUCCESS);
4067: }
4069: /* ------------ Routines to set performance monitoring options ----------- */
4071: /*MC
4072: SNESMonitorFunction - functional form passed to `SNESMonitorSet()` to monitor convergence of nonlinear solver
4074: Synopsis:
4075: #include <petscsnes.h>
4076: PetscErrorCode SNESMonitorFunction(SNES snes, PetscInt its, PetscReal norm, void *mctx)
4078: Collective
4080: Input Parameters:
4081: + snes - the `SNES` context
4082: . its - iteration number
4083: . norm - 2-norm function value (may be estimated)
4084: - mctx - [optional] monitoring context
4086: Level: advanced
4088: .seealso: [](ch_snes), `SNESMonitorSet()`, `SNESMonitorSet()`, `SNESMonitorGet()`
4089: M*/
4091: /*@C
4092: SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
4093: iteration of the nonlinear solver to display the iteration's
4094: progress.
4096: Logically Collective
4098: Input Parameters:
4099: + snes - the `SNES` context
4100: . f - the monitor function, for the calling sequence see `SNESMonitorFunction`
4101: . mctx - [optional] user-defined context for private data for the monitor routine (use `NULL` if no context is desired)
4102: - monitordestroy - [optional] routine that frees monitor context (may be `NULL`)
4104: Options Database Keys:
4105: + -snes_monitor - sets `SNESMonitorDefault()`
4106: . -snes_monitor draw::draw_lg - sets line graph monitor,
4107: - -snes_monitor_cancel - cancels all monitors that have been hardwired into a code by calls to `SNESMonitorSet()`, but does not cancel those set via
4108: the options database.
4110: Level: intermediate
4112: Note:
4113: Several different monitoring routines may be set by calling
4114: `SNESMonitorSet()` multiple times; all will be called in the
4115: order in which they were set.
4117: Fortran Note:
4118: Only a single monitor function can be set for each `SNES` object
4120: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESMonitorDefault()`, `SNESMonitorCancel()`, `SNESMonitorFunction`
4121: @*/
4122: PetscErrorCode SNESMonitorSet(SNES snes, PetscErrorCode (*f)(SNES, PetscInt, PetscReal, void *), void *mctx, PetscErrorCode (*monitordestroy)(void **))
4123: {
4124: PetscInt i;
4125: PetscBool identical;
4127: PetscFunctionBegin;
4129: for (i = 0; i < snes->numbermonitors; i++) {
4130: PetscCall(PetscMonitorCompare((PetscErrorCode(*)(void))f, mctx, monitordestroy, (PetscErrorCode(*)(void))snes->monitor[i], snes->monitorcontext[i], snes->monitordestroy[i], &identical));
4131: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4132: }
4133: PetscCheck(snes->numbermonitors < MAXSNESMONITORS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many monitors set");
4134: snes->monitor[snes->numbermonitors] = f;
4135: snes->monitordestroy[snes->numbermonitors] = monitordestroy;
4136: snes->monitorcontext[snes->numbermonitors++] = (void *)mctx;
4137: PetscFunctionReturn(PETSC_SUCCESS);
4138: }
4140: /*@
4141: SNESMonitorCancel - Clears all the monitor functions for a `SNES` object.
4143: Logically Collective
4145: Input Parameter:
4146: . snes - the `SNES` context
4148: Options Database Key:
4149: . -snes_monitor_cancel - cancels all monitors that have been hardwired
4150: into a code by calls to `SNESMonitorSet()`, but does not cancel those
4151: set via the options database
4153: Level: intermediate
4155: Note:
4156: There is no way to clear one specific monitor from a `SNES` object.
4158: .seealso: [](ch_snes), `SNES`, `SNESMonitorGet()`, `SNESMonitorDefault()`, `SNESMonitorSet()`
4159: @*/
4160: PetscErrorCode SNESMonitorCancel(SNES snes)
4161: {
4162: PetscInt i;
4164: PetscFunctionBegin;
4166: for (i = 0; i < snes->numbermonitors; i++) {
4167: if (snes->monitordestroy[i]) PetscCall((*snes->monitordestroy[i])(&snes->monitorcontext[i]));
4168: }
4169: snes->numbermonitors = 0;
4170: PetscFunctionReturn(PETSC_SUCCESS);
4171: }
4173: /*MC
4174: SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver
4176: Synopsis:
4177: #include <petscsnes.h>
4178: PetscErrorCode SNESConvergenceTest(SNES snes, PetscInt it, PetscReal xnorm, PetscReal gnorm, PetscReal f, SNESConvergedReason *reason, void *cctx)
4180: Collective
4182: Input Parameters:
4183: + snes - the `SNES` context
4184: . it - current iteration (0 is the first and is before any Newton step)
4185: . xnorm - 2-norm of current iterate
4186: . gnorm - 2-norm of current step
4187: . f - 2-norm of function
4188: - cctx - [optional] convergence context
4190: Output Parameter:
4191: . reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected
4193: Level: intermediate
4195: .seealso: [](ch_snes), `SNES`, `SNESSolve`, `SNESSetConvergenceTest()`, `SNESGetConvergenceTest()`
4196: M*/
4198: /*@C
4199: SNESSetConvergenceTest - Sets the function that is to be used
4200: to test for convergence of the nonlinear iterative solution.
4202: Logically Collective
4204: Input Parameters:
4205: + snes - the `SNES` context
4206: . SNESConvergenceTestFunction - routine to test for convergence
4207: . cctx - [optional] context for private data for the convergence routine (may be `NULL`)
4208: - destroy - [optional] destructor for the context (may be `NULL`; `PETSC_NULL_FUNCTION` in Fortran)
4210: Level: advanced
4212: .seealso: [](ch_snes), `SNES`, `SNESConvergedDefault()`, `SNESConvergedSkip()`, `SNESConvergenceTestFunction`
4213: @*/
4214: PetscErrorCode SNESSetConvergenceTest(SNES snes, PetscErrorCode (*SNESConvergenceTestFunction)(SNES, PetscInt, PetscReal, PetscReal, PetscReal, SNESConvergedReason *, void *), void *cctx, PetscErrorCode (*destroy)(void *))
4215: {
4216: PetscFunctionBegin;
4218: if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4219: if (snes->ops->convergeddestroy) PetscCall((*snes->ops->convergeddestroy)(snes->cnvP));
4220: snes->ops->converged = SNESConvergenceTestFunction;
4221: snes->ops->convergeddestroy = destroy;
4222: snes->cnvP = cctx;
4223: PetscFunctionReturn(PETSC_SUCCESS);
4224: }
4226: /*@
4227: SNESGetConvergedReason - Gets the reason the `SNES` iteration was stopped.
4229: Not Collective
4231: Input Parameter:
4232: . snes - the `SNES` context
4234: Output Parameter:
4235: . reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` for the individual convergence tests for complete lists
4237: Options Database Key:
4238: . -snes_converged_reason - prints the reason to standard out
4240: Level: intermediate
4242: Note:
4243: Should only be called after the call the `SNESSolve()` is complete, if it is called earlier it returns the value `SNES__CONVERGED_ITERATING`.
4245: .seealso: [](ch_snes), `SNESSolve()`, `SNESSetConvergenceTest()`, `SNESSetConvergedReason()`, `SNESConvergedReason`, `SNESGetConvergedReasonString()`
4246: @*/
4247: PetscErrorCode SNESGetConvergedReason(SNES snes, SNESConvergedReason *reason)
4248: {
4249: PetscFunctionBegin;
4251: PetscAssertPointer(reason, 2);
4252: *reason = snes->reason;
4253: PetscFunctionReturn(PETSC_SUCCESS);
4254: }
4256: /*@C
4257: SNESGetConvergedReasonString - Return a human readable string for `SNESConvergedReason`
4259: Not Collective
4261: Input Parameter:
4262: . snes - the `SNES` context
4264: Output Parameter:
4265: . strreason - a human readable string that describes `SNES` converged reason
4267: Level: beginner
4269: .seealso: [](ch_snes), `SNES`, `SNESGetConvergedReason()`
4270: @*/
4271: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char **strreason)
4272: {
4273: PetscFunctionBegin;
4275: PetscAssertPointer(strreason, 2);
4276: *strreason = SNESConvergedReasons[snes->reason];
4277: PetscFunctionReturn(PETSC_SUCCESS);
4278: }
4280: /*@
4281: SNESSetConvergedReason - Sets the reason the `SNES` iteration was stopped.
4283: Not Collective
4285: Input Parameters:
4286: + snes - the `SNES` context
4287: - reason - negative value indicates diverged, positive value converged, see `SNESConvergedReason` or the
4288: manual pages for the individual convergence tests for complete lists
4290: Level: developer
4292: Developer Note:
4293: Called inside the various `SNESSolve()` implementations
4295: .seealso: [](ch_snes), `SNESGetConvergedReason()`, `SNESSetConvergenceTest()`, `SNESConvergedReason`
4296: @*/
4297: PetscErrorCode SNESSetConvergedReason(SNES snes, SNESConvergedReason reason)
4298: {
4299: PetscFunctionBegin;
4301: PetscCheck(!snes->errorifnotconverged || reason > 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_PLIB, "SNES code should have previously errored due to negative reason");
4302: snes->reason = reason;
4303: PetscFunctionReturn(PETSC_SUCCESS);
4304: }
4306: /*@
4307: SNESSetConvergenceHistory - Sets the arrays used to hold the convergence history.
4309: Logically Collective
4311: Input Parameters:
4312: + snes - iterative context obtained from `SNESCreate()`
4313: . a - array to hold history, this array will contain the function norms computed at each step
4314: . its - integer array holds the number of linear iterations for each solve.
4315: . na - size of `a` and `its`
4316: - reset - `PETSC_TRUE` indicates each new nonlinear solve resets the history counter to zero,
4317: else it continues storing new values for new nonlinear solves after the old ones
4319: Level: intermediate
4321: Notes:
4322: If 'a' and 'its' are `NULL` then space is allocated for the history. If 'na' `PETSC_DECIDE` or `PETSC_DEFAULT` then a
4323: default array of length 10000 is allocated.
4325: This routine is useful, e.g., when running a code for purposes
4326: of accurate performance monitoring, when no I/O should be done
4327: during the section of code that is being timed.
4329: If the arrays run out of space after a number of iterations then the later values are not saved in the history
4331: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetConvergenceHistory()`
4332: @*/
4333: PetscErrorCode SNESSetConvergenceHistory(SNES snes, PetscReal a[], PetscInt its[], PetscInt na, PetscBool reset)
4334: {
4335: PetscFunctionBegin;
4337: if (a) PetscAssertPointer(a, 2);
4338: if (its) PetscAssertPointer(its, 3);
4339: if (!a) {
4340: if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
4341: PetscCall(PetscCalloc2(na, &a, na, &its));
4342: snes->conv_hist_alloc = PETSC_TRUE;
4343: }
4344: snes->conv_hist = a;
4345: snes->conv_hist_its = its;
4346: snes->conv_hist_max = (size_t)na;
4347: snes->conv_hist_len = 0;
4348: snes->conv_hist_reset = reset;
4349: PetscFunctionReturn(PETSC_SUCCESS);
4350: }
4352: #if defined(PETSC_HAVE_MATLAB)
4353: #include <engine.h> /* MATLAB include file */
4354: #include <mex.h> /* MATLAB include file */
4356: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4357: {
4358: mxArray *mat;
4359: PetscInt i;
4360: PetscReal *ar;
4362: mat = mxCreateDoubleMatrix(snes->conv_hist_len, 1, mxREAL);
4363: ar = (PetscReal *)mxGetData(mat);
4364: for (i = 0; i < snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4365: return mat;
4366: }
4367: #endif
4369: /*@C
4370: SNESGetConvergenceHistory - Gets the arrays used to hold the convergence history.
4372: Not Collective
4374: Input Parameter:
4375: . snes - iterative context obtained from `SNESCreate()`
4377: Output Parameters:
4378: + a - array to hold history, usually was set with `SNESSetConvergenceHistory()`
4379: . its - integer array holds the number of linear iterations (or
4380: negative if not converged) for each solve.
4381: - na - size of `a` and `its`
4383: Level: intermediate
4385: Note:
4386: This routine is useful, e.g., when running a code for purposes
4387: of accurate performance monitoring, when no I/O should be done
4388: during the section of code that is being timed.
4390: Fortran Note:
4391: The calling sequence for this routine in Fortran is
4392: .vb
4393: call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)
4394: .ve
4396: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetConvergenceHistory()`
4397: @*/
4398: PetscErrorCode SNESGetConvergenceHistory(SNES snes, PetscReal *a[], PetscInt *its[], PetscInt *na)
4399: {
4400: PetscFunctionBegin;
4402: if (a) *a = snes->conv_hist;
4403: if (its) *its = snes->conv_hist_its;
4404: if (na) *na = (PetscInt)snes->conv_hist_len;
4405: PetscFunctionReturn(PETSC_SUCCESS);
4406: }
4408: /*@C
4409: SNESSetUpdate - Sets the general-purpose update function called
4410: at the beginning of every iteration of the nonlinear solve. Specifically
4411: it is called just before the Jacobian is "evaluated".
4413: Logically Collective
4415: Input Parameters:
4416: + snes - The nonlinear solver context
4417: - func - The function
4419: Calling sequence of `func`:
4420: + snes - the nonlinear solver context
4421: - step - The current step of the iteration
4423: Level: advanced
4425: Notes:
4426: 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
4427: to `SNESSetFunction()`, or `SNESSetPicard()`
4428: This is not used by most users.
4430: 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.
4432: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetJacobian()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchSetPostCheck()`, `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRSetPostCheck()`,
4433: `SNESMonitorSet()`, `SNESSetDivergenceTest()`
4434: @*/
4435: PetscErrorCode SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES snes, PetscInt step))
4436: {
4437: PetscFunctionBegin;
4439: snes->ops->update = func;
4440: PetscFunctionReturn(PETSC_SUCCESS);
4441: }
4443: /*@C
4444: SNESConvergedReasonView - Displays the reason a `SNES` solve converged or diverged to a viewer
4446: Collective
4448: Input Parameters:
4449: + snes - iterative context obtained from `SNESCreate()`
4450: - viewer - the viewer to display the reason
4452: Options Database Keys:
4453: + -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4454: - -snes_converged_reason ::failed - only print reason and number of iterations when diverged
4456: Level: beginner
4458: Note:
4459: To change the format of the output call `PetscViewerPushFormat`(viewer,format) before this call. Use `PETSC_VIEWER_DEFAULT` for the default,
4460: use `PETSC_VIEWER_FAILED` to only display a reason if it fails.
4462: .seealso: [](ch_snes), `SNESConvergedReason`, `PetscViewer`, `SNES`,
4463: `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`, `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`,
4464: `SNESConvergedReasonViewFromOptions()`,
4465: `PetscViewerPushFormat()`, `PetscViewerPopFormat()`
4466: @*/
4467: PetscErrorCode SNESConvergedReasonView(SNES snes, PetscViewer viewer)
4468: {
4469: PetscViewerFormat format;
4470: PetscBool isAscii;
4472: PetscFunctionBegin;
4473: if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4474: PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isAscii));
4475: if (isAscii) {
4476: PetscCall(PetscViewerGetFormat(viewer, &format));
4477: PetscCall(PetscViewerASCIIAddTab(viewer, ((PetscObject)snes)->tablevel + 1));
4478: if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4479: DM dm;
4480: Vec u;
4481: PetscDS prob;
4482: PetscInt Nf, f;
4483: PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4484: void **exactCtx;
4485: PetscReal error;
4487: PetscCall(SNESGetDM(snes, &dm));
4488: PetscCall(SNESGetSolution(snes, &u));
4489: PetscCall(DMGetDS(dm, &prob));
4490: PetscCall(PetscDSGetNumFields(prob, &Nf));
4491: PetscCall(PetscMalloc2(Nf, &exactSol, Nf, &exactCtx));
4492: for (f = 0; f < Nf; ++f) PetscCall(PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]));
4493: PetscCall(DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error));
4494: PetscCall(PetscFree2(exactSol, exactCtx));
4495: if (error < 1.0e-11) PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n"));
4496: else PetscCall(PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", (double)error));
4497: }
4498: if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4499: if (((PetscObject)snes)->prefix) {
4500: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve converged due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4501: } else {
4502: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve converged due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4503: }
4504: } else if (snes->reason <= 0) {
4505: if (((PetscObject)snes)->prefix) {
4506: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear %s solve did not converge due to %s iterations %" PetscInt_FMT "\n", ((PetscObject)snes)->prefix, SNESConvergedReasons[snes->reason], snes->iter));
4507: } else {
4508: PetscCall(PetscViewerASCIIPrintf(viewer, "Nonlinear solve did not converge due to %s iterations %" PetscInt_FMT "\n", SNESConvergedReasons[snes->reason], snes->iter));
4509: }
4510: }
4511: PetscCall(PetscViewerASCIISubtractTab(viewer, ((PetscObject)snes)->tablevel + 1));
4512: }
4513: PetscFunctionReturn(PETSC_SUCCESS);
4514: }
4516: /*@C
4517: SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4518: end of the nonlinear solver to display the convergence reason of the nonlinear solver.
4520: Logically Collective
4522: Input Parameters:
4523: + snes - the `SNES` context
4524: . f - the `SNESConvergedReason` view function
4525: . vctx - [optional] user-defined context for private data for the `SNESConvergedReason` view function (use `NULL` if no context is desired)
4526: - reasonviewdestroy - [optional] routine that frees the context (may be `NULL`)
4528: Calling sequence of `f`:
4529: + snes - the `SNES` context
4530: - vctx - [optional] user-defined context for private data for the function
4532: Calling sequence of `reasonviewerdestroy`:
4533: . vctx - [optional] user-defined context for private data for the function
4535: Options Database Keys:
4536: + -snes_converged_reason - sets a default `SNESConvergedReasonView()`
4537: - -snes_converged_reason_view_cancel - cancels all converged reason viewers that have been hardwired into a code by
4538: calls to `SNESConvergedReasonViewSet()`, but does not cancel those set via the options database.
4540: Level: intermediate
4542: Note:
4543: Several different converged reason view routines may be set by calling
4544: `SNESConvergedReasonViewSet()` multiple times; all will be called in the
4545: order in which they were set.
4547: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESConvergedReason`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`, `SNESConvergedReasonViewCancel()`
4548: @*/
4549: PetscErrorCode SNESConvergedReasonViewSet(SNES snes, PetscErrorCode (*f)(SNES snes, void *vctx), void *vctx, PetscErrorCode (*reasonviewdestroy)(void **vctx))
4550: {
4551: PetscInt i;
4552: PetscBool identical;
4554: PetscFunctionBegin;
4556: for (i = 0; i < snes->numberreasonviews; i++) {
4557: PetscCall(PetscMonitorCompare((PetscErrorCode(*)(void))f, vctx, reasonviewdestroy, (PetscErrorCode(*)(void))snes->reasonview[i], snes->reasonviewcontext[i], snes->reasonviewdestroy[i], &identical));
4558: if (identical) PetscFunctionReturn(PETSC_SUCCESS);
4559: }
4560: PetscCheck(snes->numberreasonviews < MAXSNESREASONVIEWS, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Too many SNES reasonview set");
4561: snes->reasonview[snes->numberreasonviews] = f;
4562: snes->reasonviewdestroy[snes->numberreasonviews] = reasonviewdestroy;
4563: snes->reasonviewcontext[snes->numberreasonviews++] = (void *)vctx;
4564: PetscFunctionReturn(PETSC_SUCCESS);
4565: }
4567: /*@
4568: SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a `SNESConvergedReason` is to be viewed at the end of `SNESSolve()`
4569: All the user-provided convergedReasonView routines will be involved as well, if they exist.
4571: Collective
4573: Input Parameter:
4574: . snes - the `SNES` object
4576: Level: advanced
4578: .seealso: [](ch_snes), `SNES`, `SNESConvergedReason`, `SNESConvergedReasonViewSet()`, `SNESCreate()`, `SNESSetUp()`, `SNESDestroy()`,
4579: `SNESSetTolerances()`, `SNESConvergedDefault()`, `SNESGetConvergedReason()`, `SNESConvergedReasonView()`
4580: @*/
4581: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4582: {
4583: PetscViewer viewer;
4584: PetscBool flg;
4585: static PetscBool incall = PETSC_FALSE;
4586: PetscViewerFormat format;
4587: PetscInt i;
4589: PetscFunctionBegin;
4590: if (incall) PetscFunctionReturn(PETSC_SUCCESS);
4591: incall = PETSC_TRUE;
4593: /* All user-provided viewers are called first, if they exist. */
4594: for (i = 0; i < snes->numberreasonviews; i++) PetscCall((*snes->reasonview[i])(snes, snes->reasonviewcontext[i]));
4596: /* Call PETSc default routine if users ask for it */
4597: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_converged_reason", &viewer, &format, &flg));
4598: if (flg) {
4599: PetscCall(PetscViewerPushFormat(viewer, format));
4600: PetscCall(SNESConvergedReasonView(snes, viewer));
4601: PetscCall(PetscViewerPopFormat(viewer));
4602: PetscCall(PetscOptionsRestoreViewer(&viewer));
4603: }
4604: incall = PETSC_FALSE;
4605: PetscFunctionReturn(PETSC_SUCCESS);
4606: }
4608: /*@
4609: SNESSolve - Solves a nonlinear system F(x) = b.
4611: Collective
4613: Input Parameters:
4614: + snes - the `SNES` context
4615: . b - the constant part of the equation F(x) = b, or `NULL` to use zero.
4616: - x - the solution vector.
4618: Level: beginner
4620: Note:
4621: The user should initialize the vector, `x`, with the initial guess
4622: for the nonlinear solve prior to calling `SNESSolve()` or use `SNESSetInitialSolution()`. In particular,
4623: to employ an initial guess of zero, the user should explicitly set
4624: this vector to zero by calling `VecSet()`.
4626: .seealso: [](ch_snes), `SNES`, `SNESCreate()`, `SNESDestroy()`, `SNESSetFunction()`, `SNESSetJacobian()`, `SNESSetGridSequence()`, `SNESGetSolution()`,
4627: `SNESNewtonTRSetPreCheck()`, `SNESNewtonTRGetPreCheck()`, `SNESNewtonTRSetPostCheck()`, `SNESNewtonTRGetPostCheck()`,
4628: `SNESLineSearchSetPostCheck()`, `SNESLineSearchGetPostCheck()`, `SNESLineSearchSetPreCheck()`, `SNESLineSearchGetPreCheck()`, `SNESSetInitialSolution()`
4629: @*/
4630: PetscErrorCode SNESSolve(SNES snes, Vec b, Vec x)
4631: {
4632: PetscBool flg;
4633: PetscInt grid;
4634: Vec xcreated = NULL;
4635: DM dm;
4637: PetscFunctionBegin;
4640: if (x) PetscCheckSameComm(snes, 1, x, 3);
4642: if (b) PetscCheckSameComm(snes, 1, b, 2);
4644: /* High level operations using the nonlinear solver */
4645: {
4646: PetscViewer viewer;
4647: PetscViewerFormat format;
4648: PetscInt num;
4649: PetscBool flg;
4650: static PetscBool incall = PETSC_FALSE;
4652: if (!incall) {
4653: /* Estimate the convergence rate of the discretization */
4654: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg));
4655: if (flg) {
4656: PetscConvEst conv;
4657: DM dm;
4658: PetscReal *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4659: PetscInt Nf;
4661: incall = PETSC_TRUE;
4662: PetscCall(SNESGetDM(snes, &dm));
4663: PetscCall(DMGetNumFields(dm, &Nf));
4664: PetscCall(PetscCalloc1(Nf, &alpha));
4665: PetscCall(PetscConvEstCreate(PetscObjectComm((PetscObject)snes), &conv));
4666: PetscCall(PetscConvEstSetSolver(conv, (PetscObject)snes));
4667: PetscCall(PetscConvEstSetFromOptions(conv));
4668: PetscCall(PetscConvEstSetUp(conv));
4669: PetscCall(PetscConvEstGetConvRate(conv, alpha));
4670: PetscCall(PetscViewerPushFormat(viewer, format));
4671: PetscCall(PetscConvEstRateView(conv, alpha, viewer));
4672: PetscCall(PetscViewerPopFormat(viewer));
4673: PetscCall(PetscOptionsRestoreViewer(&viewer));
4674: PetscCall(PetscConvEstDestroy(&conv));
4675: PetscCall(PetscFree(alpha));
4676: incall = PETSC_FALSE;
4677: }
4678: /* Adaptively refine the initial grid */
4679: num = 1;
4680: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_initial", &num, &flg));
4681: if (flg) {
4682: DMAdaptor adaptor;
4684: incall = PETSC_TRUE;
4685: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4686: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4687: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4688: PetscCall(DMAdaptorSetFromOptions(adaptor));
4689: PetscCall(DMAdaptorSetUp(adaptor));
4690: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x));
4691: PetscCall(DMAdaptorDestroy(&adaptor));
4692: incall = PETSC_FALSE;
4693: }
4694: /* Use grid sequencing to adapt */
4695: num = 0;
4696: PetscCall(PetscOptionsGetInt(NULL, ((PetscObject)snes)->prefix, "-snes_adapt_sequence", &num, NULL));
4697: if (num) {
4698: DMAdaptor adaptor;
4700: incall = PETSC_TRUE;
4701: PetscCall(DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor));
4702: PetscCall(DMAdaptorSetSolver(adaptor, snes));
4703: PetscCall(DMAdaptorSetSequenceLength(adaptor, num));
4704: PetscCall(DMAdaptorSetFromOptions(adaptor));
4705: PetscCall(DMAdaptorSetUp(adaptor));
4706: PetscCall(DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x));
4707: PetscCall(DMAdaptorDestroy(&adaptor));
4708: incall = PETSC_FALSE;
4709: }
4710: }
4711: }
4712: if (!x) x = snes->vec_sol;
4713: if (!x) {
4714: PetscCall(SNESGetDM(snes, &dm));
4715: PetscCall(DMCreateGlobalVector(dm, &xcreated));
4716: x = xcreated;
4717: }
4718: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view_pre"));
4720: for (grid = 0; grid < snes->gridsequence; grid++) PetscCall(PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4721: for (grid = 0; grid < snes->gridsequence + 1; grid++) {
4722: /* set solution vector */
4723: if (!grid) PetscCall(PetscObjectReference((PetscObject)x));
4724: PetscCall(VecDestroy(&snes->vec_sol));
4725: snes->vec_sol = x;
4726: PetscCall(SNESGetDM(snes, &dm));
4728: /* set affine vector if provided */
4729: if (b) PetscCall(PetscObjectReference((PetscObject)b));
4730: PetscCall(VecDestroy(&snes->vec_rhs));
4731: snes->vec_rhs = b;
4733: 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");
4734: PetscCheck(snes->vec_func != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be function vector");
4735: PetscCheck(snes->vec_rhs != snes->vec_sol, PETSC_COMM_SELF, PETSC_ERR_ARG_IDN, "Solution vector cannot be right-hand side vector");
4736: if (!snes->vec_sol_update /* && snes->vec_sol */) PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_sol_update));
4737: PetscCall(DMShellSetGlobalVector(dm, snes->vec_sol));
4738: PetscCall(SNESSetUp(snes));
4740: if (!grid) {
4741: if (snes->ops->computeinitialguess) PetscCallBack("SNES callback compute initial guess", (*snes->ops->computeinitialguess)(snes, snes->vec_sol, snes->initialguessP));
4742: }
4744: if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4745: if (snes->counters_reset) {
4746: snes->nfuncs = 0;
4747: snes->linear_its = 0;
4748: snes->numFailures = 0;
4749: }
4751: snes->reason = SNES_CONVERGED_ITERATING;
4752: PetscCall(PetscLogEventBegin(SNES_Solve, snes, 0, 0, 0));
4753: PetscUseTypeMethod(snes, solve);
4754: PetscCall(PetscLogEventEnd(SNES_Solve, snes, 0, 0, 0));
4755: PetscCheck(snes->reason, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Internal error, solver %s returned without setting converged reason", ((PetscObject)snes)->type_name);
4756: snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */
4758: if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4759: if (snes->lagpre_persist) snes->pre_iter += snes->iter;
4761: PetscCall(PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes), ((PetscObject)snes)->options, ((PetscObject)snes)->prefix, "-snes_test_local_min", NULL, NULL, &flg));
4762: if (flg && !PetscPreLoadingOn) PetscCall(SNESTestLocalMin(snes));
4763: /* Call converged reason views. This may involve user-provided viewers as well */
4764: PetscCall(SNESConvergedReasonViewFromOptions(snes));
4766: if (snes->errorifnotconverged) PetscCheck(snes->reason >= 0, PetscObjectComm((PetscObject)snes), PETSC_ERR_NOT_CONVERGED, "SNESSolve has not converged");
4767: if (snes->reason < 0) break;
4768: if (grid < snes->gridsequence) {
4769: DM fine;
4770: Vec xnew;
4771: Mat interp;
4773: PetscCall(DMRefine(snes->dm, PetscObjectComm((PetscObject)snes), &fine));
4774: PetscCheck(fine, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_INCOMP, "DMRefine() did not perform any refinement, cannot continue grid sequencing");
4775: PetscCall(DMCreateInterpolation(snes->dm, fine, &interp, NULL));
4776: PetscCall(DMCreateGlobalVector(fine, &xnew));
4777: PetscCall(MatInterpolate(interp, x, xnew));
4778: PetscCall(DMInterpolate(snes->dm, interp, fine));
4779: PetscCall(MatDestroy(&interp));
4780: x = xnew;
4782: PetscCall(SNESReset(snes));
4783: PetscCall(SNESSetDM(snes, fine));
4784: PetscCall(SNESResetFromOptions(snes));
4785: PetscCall(DMDestroy(&fine));
4786: PetscCall(PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes))));
4787: }
4788: }
4789: PetscCall(SNESViewFromOptions(snes, NULL, "-snes_view"));
4790: PetscCall(VecViewFromOptions(snes->vec_sol, (PetscObject)snes, "-snes_view_solution"));
4791: PetscCall(DMMonitor(snes->dm));
4792: PetscCall(SNESMonitorPauseFinal_Internal(snes));
4794: PetscCall(VecDestroy(&xcreated));
4795: PetscCall(PetscObjectSAWsBlock((PetscObject)snes));
4796: PetscFunctionReturn(PETSC_SUCCESS);
4797: }
4799: /* --------- Internal routines for SNES Package --------- */
4801: /*@C
4802: SNESSetType - Sets the method for the nonlinear solver.
4804: Collective
4806: Input Parameters:
4807: + snes - the `SNES` context
4808: - type - a known method
4810: Options Database Key:
4811: . -snes_type <type> - Sets the method; use -help for a list
4812: of available methods (for instance, newtonls or newtontr)
4814: Level: intermediate
4816: Notes:
4817: See "petsc/include/petscsnes.h" for available methods (for instance)
4818: + `SNESNEWTONLS` - Newton's method with line search
4819: (systems of nonlinear equations)
4820: - `SNESNEWTONTR` - Newton's method with trust region
4821: (systems of nonlinear equations)
4823: Normally, it is best to use the `SNESSetFromOptions()` command and then
4824: set the `SNES` solver type from the options database rather than by using
4825: this routine. Using the options database provides the user with
4826: maximum flexibility in evaluating the many nonlinear solvers.
4827: The `SNESSetType()` routine is provided for those situations where it
4828: is necessary to set the nonlinear solver independently of the command
4829: line or options database. This might be the case, for example, when
4830: the choice of solver changes during the execution of the program,
4831: and the user's application is taking responsibility for choosing the
4832: appropriate method.
4834: Developer Note:
4835: `SNESRegister()` adds a constructor for a new `SNESType` to `SNESList`, `SNESSetType()` locates
4836: the constructor in that list and calls it to create the specific object.
4838: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESType`, `SNESCreate()`, `SNESDestroy()`, `SNESGetType()`, `SNESSetFromOptions()`
4839: @*/
4840: PetscErrorCode SNESSetType(SNES snes, SNESType type)
4841: {
4842: PetscBool match;
4843: PetscErrorCode (*r)(SNES);
4845: PetscFunctionBegin;
4847: PetscAssertPointer(type, 2);
4849: PetscCall(PetscObjectTypeCompare((PetscObject)snes, type, &match));
4850: if (match) PetscFunctionReturn(PETSC_SUCCESS);
4852: PetscCall(PetscFunctionListFind(SNESList, type, &r));
4853: PetscCheck(r, PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_UNKNOWN_TYPE, "Unable to find requested SNES type %s", type);
4854: /* Destroy the previous private SNES context */
4855: PetscTryTypeMethod(snes, destroy);
4856: /* Reinitialize function pointers in SNESOps structure */
4857: snes->ops->setup = NULL;
4858: snes->ops->solve = NULL;
4859: snes->ops->view = NULL;
4860: snes->ops->setfromoptions = NULL;
4861: snes->ops->destroy = NULL;
4863: /* It may happen the user has customized the line search before calling SNESSetType */
4864: if (((PetscObject)snes)->type_name) PetscCall(SNESLineSearchDestroy(&snes->linesearch));
4866: /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4867: snes->setupcalled = PETSC_FALSE;
4869: PetscCall(PetscObjectChangeTypeName((PetscObject)snes, type));
4870: PetscCall((*r)(snes));
4871: PetscFunctionReturn(PETSC_SUCCESS);
4872: }
4874: /*@C
4875: SNESGetType - Gets the `SNES` method type and name (as a string).
4877: Not Collective
4879: Input Parameter:
4880: . snes - nonlinear solver context
4882: Output Parameter:
4883: . type - `SNES` method (a character string)
4885: Level: intermediate
4887: .seealso: [](ch_snes), `SNESSetType()`, `SNESType`, `SNESSetFromOptions()`, `SNES`
4888: @*/
4889: PetscErrorCode SNESGetType(SNES snes, SNESType *type)
4890: {
4891: PetscFunctionBegin;
4893: PetscAssertPointer(type, 2);
4894: *type = ((PetscObject)snes)->type_name;
4895: PetscFunctionReturn(PETSC_SUCCESS);
4896: }
4898: /*@
4899: SNESSetSolution - Sets the solution vector for use by the `SNES` routines.
4901: Logically Collective
4903: Input Parameters:
4904: + snes - the `SNES` context obtained from `SNESCreate()`
4905: - u - the solution vector
4907: Level: beginner
4909: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESGetSolution()`, `Vec`
4910: @*/
4911: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4912: {
4913: DM dm;
4915: PetscFunctionBegin;
4918: PetscCall(PetscObjectReference((PetscObject)u));
4919: PetscCall(VecDestroy(&snes->vec_sol));
4921: snes->vec_sol = u;
4923: PetscCall(SNESGetDM(snes, &dm));
4924: PetscCall(DMShellSetGlobalVector(dm, u));
4925: PetscFunctionReturn(PETSC_SUCCESS);
4926: }
4928: /*@
4929: SNESGetSolution - Returns the vector where the approximate solution is
4930: stored. This is the fine grid solution when using `SNESSetGridSequence()`.
4932: Not Collective, but `x` is parallel if `snes` is parallel
4934: Input Parameter:
4935: . snes - the `SNES` context
4937: Output Parameter:
4938: . x - the solution
4940: Level: intermediate
4942: .seealso: [](ch_snes), `SNESSetSolution()`, `SNESSolve()`, `SNES`, `SNESGetSolutionUpdate()`, `SNESGetFunction()`
4943: @*/
4944: PetscErrorCode SNESGetSolution(SNES snes, Vec *x)
4945: {
4946: PetscFunctionBegin;
4948: PetscAssertPointer(x, 2);
4949: *x = snes->vec_sol;
4950: PetscFunctionReturn(PETSC_SUCCESS);
4951: }
4953: /*@
4954: SNESGetSolutionUpdate - Returns the vector where the solution update is
4955: stored.
4957: Not Collective, but `x` is parallel if `snes` is parallel
4959: Input Parameter:
4960: . snes - the `SNES` context
4962: Output Parameter:
4963: . x - the solution update
4965: Level: advanced
4967: .seealso: [](ch_snes), `SNES`, `SNESGetSolution()`, `SNESGetFunction()`
4968: @*/
4969: PetscErrorCode SNESGetSolutionUpdate(SNES snes, Vec *x)
4970: {
4971: PetscFunctionBegin;
4973: PetscAssertPointer(x, 2);
4974: *x = snes->vec_sol_update;
4975: PetscFunctionReturn(PETSC_SUCCESS);
4976: }
4978: /*@C
4979: SNESGetFunction - Returns the function that defines the nonlinear system set with `SNESSetFunction()`
4981: Not Collective, but `r` is parallel if `snes` is parallel. Collective if `r` is requested, but has not been created yet.
4983: Input Parameter:
4984: . snes - the `SNES` context
4986: Output Parameters:
4987: + r - the vector that is used to store residuals (or `NULL` if you don't want it)
4988: . f - the function (or `NULL` if you don't want it); for calling sequence see `SNESFunctionFn`
4989: - ctx - the function context (or `NULL` if you don't want it)
4991: Level: advanced
4993: Note:
4994: The vector `r` DOES NOT, in general, contain the current value of the `SNES` nonlinear function
4996: .seealso: [](ch_snes), `SNES`, `SNESSolve()`, `SNESSetFunction()`, `SNESGetSolution()`, `SNESFunctionFn`
4997: @*/
4998: PetscErrorCode SNESGetFunction(SNES snes, Vec *r, SNESFunctionFn **f, void **ctx)
4999: {
5000: DM dm;
5002: PetscFunctionBegin;
5004: if (r) {
5005: if (!snes->vec_func) {
5006: if (snes->vec_rhs) {
5007: PetscCall(VecDuplicate(snes->vec_rhs, &snes->vec_func));
5008: } else if (snes->vec_sol) {
5009: PetscCall(VecDuplicate(snes->vec_sol, &snes->vec_func));
5010: } else if (snes->dm) {
5011: PetscCall(DMCreateGlobalVector(snes->dm, &snes->vec_func));
5012: }
5013: }
5014: *r = snes->vec_func;
5015: }
5016: PetscCall(SNESGetDM(snes, &dm));
5017: PetscCall(DMSNESGetFunction(dm, f, ctx));
5018: PetscFunctionReturn(PETSC_SUCCESS);
5019: }
5021: /*@C
5022: SNESGetNGS - Returns the function and context set with `SNESSetNGS()`
5024: Input Parameter:
5025: . snes - the `SNES` context
5027: Output Parameters:
5028: + f - the function (or `NULL`) see `SNESNGSFn` for calling sequence
5029: - ctx - the function context (or `NULL`)
5031: Level: advanced
5033: .seealso: [](ch_snes), `SNESSetNGS()`, `SNESGetFunction()`, `SNESNGSFn`
5034: @*/
5035: PetscErrorCode SNESGetNGS(SNES snes, SNESNGSFn **f, void **ctx)
5036: {
5037: DM dm;
5039: PetscFunctionBegin;
5041: PetscCall(SNESGetDM(snes, &dm));
5042: PetscCall(DMSNESGetNGS(dm, f, ctx));
5043: PetscFunctionReturn(PETSC_SUCCESS);
5044: }
5046: /*@C
5047: SNESSetOptionsPrefix - Sets the prefix used for searching for all
5048: `SNES` options in the database.
5050: Logically Collective
5052: Input Parameters:
5053: + snes - the `SNES` context
5054: - prefix - the prefix to prepend to all option names
5056: Level: advanced
5058: Note:
5059: A hyphen (-) must NOT be given at the beginning of the prefix name.
5060: The first character of all runtime options is AUTOMATICALLY the hyphen.
5062: .seealso: [](ch_snes), `SNES`, `SNESSetFromOptions()`, `SNESAppendOptionsPrefix()`
5063: @*/
5064: PetscErrorCode SNESSetOptionsPrefix(SNES snes, const char prefix[])
5065: {
5066: PetscFunctionBegin;
5068: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes, prefix));
5069: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5070: if (snes->linesearch) {
5071: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5072: PetscCall(PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch, prefix));
5073: }
5074: PetscCall(KSPSetOptionsPrefix(snes->ksp, prefix));
5075: PetscFunctionReturn(PETSC_SUCCESS);
5076: }
5078: /*@C
5079: SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
5080: `SNES` options in the database.
5082: Logically Collective
5084: Input Parameters:
5085: + snes - the `SNES` context
5086: - prefix - the prefix to prepend to all option names
5088: Level: advanced
5090: Note:
5091: A hyphen (-) must NOT be given at the beginning of the prefix name.
5092: The first character of all runtime options is AUTOMATICALLY the hyphen.
5094: .seealso: [](ch_snes), `SNESGetOptionsPrefix()`, `SNESSetOptionsPrefix()`
5095: @*/
5096: PetscErrorCode SNESAppendOptionsPrefix(SNES snes, const char prefix[])
5097: {
5098: PetscFunctionBegin;
5100: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes, prefix));
5101: if (!snes->ksp) PetscCall(SNESGetKSP(snes, &snes->ksp));
5102: if (snes->linesearch) {
5103: PetscCall(SNESGetLineSearch(snes, &snes->linesearch));
5104: PetscCall(PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch, prefix));
5105: }
5106: PetscCall(KSPAppendOptionsPrefix(snes->ksp, prefix));
5107: PetscFunctionReturn(PETSC_SUCCESS);
5108: }
5110: /*@C
5111: SNESGetOptionsPrefix - Gets the prefix used for searching for all
5112: `SNES` options in the database.
5114: Not Collective
5116: Input Parameter:
5117: . snes - the `SNES` context
5119: Output Parameter:
5120: . prefix - pointer to the prefix string used
5122: Level: advanced
5124: Fortran Note:
5125: The user should pass in a string 'prefix' of
5126: sufficient length to hold the prefix.
5128: .seealso: [](ch_snes), `SNES`, `SNESSetOptionsPrefix()`, `SNESAppendOptionsPrefix()`
5129: @*/
5130: PetscErrorCode SNESGetOptionsPrefix(SNES snes, const char *prefix[])
5131: {
5132: PetscFunctionBegin;
5134: PetscCall(PetscObjectGetOptionsPrefix((PetscObject)snes, prefix));
5135: PetscFunctionReturn(PETSC_SUCCESS);
5136: }
5138: /*@C
5139: SNESRegister - Adds a method to the nonlinear solver package.
5141: Not Collective
5143: Input Parameters:
5144: + sname - name of a new user-defined solver
5145: - function - routine to create method context
5147: Level: advanced
5149: Note:
5150: `SNESRegister()` may be called multiple times to add several user-defined solvers.
5152: Example Usage:
5153: .vb
5154: SNESRegister("my_solver", MySolverCreate);
5155: .ve
5157: Then, your solver can be chosen with the procedural interface via
5158: $ SNESSetType(snes, "my_solver")
5159: or at runtime via the option
5160: $ -snes_type my_solver
5162: .seealso: [](ch_snes), `SNESRegisterAll()`, `SNESRegisterDestroy()`
5163: @*/
5164: PetscErrorCode SNESRegister(const char sname[], PetscErrorCode (*function)(SNES))
5165: {
5166: PetscFunctionBegin;
5167: PetscCall(SNESInitializePackage());
5168: PetscCall(PetscFunctionListAdd(&SNESList, sname, function));
5169: PetscFunctionReturn(PETSC_SUCCESS);
5170: }
5172: PetscErrorCode SNESTestLocalMin(SNES snes)
5173: {
5174: PetscInt N, i, j;
5175: Vec u, uh, fh;
5176: PetscScalar value;
5177: PetscReal norm;
5179: PetscFunctionBegin;
5180: PetscCall(SNESGetSolution(snes, &u));
5181: PetscCall(VecDuplicate(u, &uh));
5182: PetscCall(VecDuplicate(u, &fh));
5184: /* currently only works for sequential */
5185: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "Testing FormFunction() for local min\n"));
5186: PetscCall(VecGetSize(u, &N));
5187: for (i = 0; i < N; i++) {
5188: PetscCall(VecCopy(u, uh));
5189: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), "i = %" PetscInt_FMT "\n", i));
5190: for (j = -10; j < 11; j++) {
5191: value = PetscSign(j) * PetscExpReal(PetscAbs(j) - 10.0);
5192: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5193: PetscCall(SNESComputeFunction(snes, uh, fh));
5194: PetscCall(VecNorm(fh, NORM_2, &norm));
5195: PetscCall(PetscPrintf(PetscObjectComm((PetscObject)snes), " j norm %" PetscInt_FMT " %18.16e\n", j, (double)norm));
5196: value = -value;
5197: PetscCall(VecSetValue(uh, i, value, ADD_VALUES));
5198: }
5199: }
5200: PetscCall(VecDestroy(&uh));
5201: PetscCall(VecDestroy(&fh));
5202: PetscFunctionReturn(PETSC_SUCCESS);
5203: }
5205: /*@
5206: SNESKSPSetUseEW - Sets `SNES` to the use Eisenstat-Walker method for
5207: computing relative tolerance for linear solvers within an inexact
5208: Newton method.
5210: Logically Collective
5212: Input Parameters:
5213: + snes - `SNES` context
5214: - flag - `PETSC_TRUE` or `PETSC_FALSE`
5216: Options Database Keys:
5217: + -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5218: . -snes_ksp_ew_version ver - version of Eisenstat-Walker method
5219: . -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5220: . -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5221: . -snes_ksp_ew_gamma <gamma> - Sets gamma
5222: . -snes_ksp_ew_alpha <alpha> - Sets alpha
5223: . -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5224: - -snes_ksp_ew_threshold <threshold> - Sets threshold
5226: Level: advanced
5228: Note:
5229: The default is to use a constant relative tolerance for
5230: the inner linear solvers. Alternatively, one can use the
5231: Eisenstat-Walker method {cite}`ew96`, where the relative convergence tolerance
5232: is reset at each Newton iteration according progress of the nonlinear
5233: solver.
5235: .seealso: [](ch_snes), `KSP`, `SNES`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5236: @*/
5237: PetscErrorCode SNESKSPSetUseEW(SNES snes, PetscBool flag)
5238: {
5239: PetscFunctionBegin;
5242: snes->ksp_ewconv = flag;
5243: PetscFunctionReturn(PETSC_SUCCESS);
5244: }
5246: /*@
5247: SNESKSPGetUseEW - Gets if `SNES` is using Eisenstat-Walker method
5248: for computing relative tolerance for linear solvers within an
5249: inexact Newton method.
5251: Not Collective
5253: Input Parameter:
5254: . snes - `SNES` context
5256: Output Parameter:
5257: . flag - `PETSC_TRUE` or `PETSC_FALSE`
5259: Level: advanced
5261: .seealso: [](ch_snes), `SNESKSPSetUseEW()`, `SNESKSPGetParametersEW()`, `SNESKSPSetParametersEW()`
5262: @*/
5263: PetscErrorCode SNESKSPGetUseEW(SNES snes, PetscBool *flag)
5264: {
5265: PetscFunctionBegin;
5267: PetscAssertPointer(flag, 2);
5268: *flag = snes->ksp_ewconv;
5269: PetscFunctionReturn(PETSC_SUCCESS);
5270: }
5272: /*@
5273: SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5274: convergence criteria for the linear solvers within an inexact
5275: Newton method.
5277: Logically Collective
5279: Input Parameters:
5280: + snes - `SNES` context
5281: . version - version 1, 2 (default is 2), 3 or 4
5282: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5283: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5284: . gamma - multiplicative factor for version 2 rtol computation
5285: (0 <= gamma2 <= 1)
5286: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5287: . alpha2 - power for safeguard
5288: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5290: Level: advanced
5292: Notes:
5293: Version 3 was contributed by Luis Chacon, June 2006.
5295: Use `PETSC_DEFAULT` to retain the default for any of the parameters.
5297: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPGetParametersEW()`
5298: @*/
5299: PetscErrorCode SNESKSPSetParametersEW(SNES snes, PetscInt version, PetscReal rtol_0, PetscReal rtol_max, PetscReal gamma, PetscReal alpha, PetscReal alpha2, PetscReal threshold)
5300: {
5301: SNESKSPEW *kctx;
5303: PetscFunctionBegin;
5305: kctx = (SNESKSPEW *)snes->kspconvctx;
5306: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5315: if (version != PETSC_DEFAULT) kctx->version = version;
5316: if (rtol_0 != (PetscReal)PETSC_DEFAULT) kctx->rtol_0 = rtol_0;
5317: if (rtol_max != (PetscReal)PETSC_DEFAULT) kctx->rtol_max = rtol_max;
5318: if (gamma != (PetscReal)PETSC_DEFAULT) kctx->gamma = gamma;
5319: if (alpha != (PetscReal)PETSC_DEFAULT) kctx->alpha = alpha;
5320: if (alpha2 != (PetscReal)PETSC_DEFAULT) kctx->alpha2 = alpha2;
5321: if (threshold != (PetscReal)PETSC_DEFAULT) kctx->threshold = threshold;
5323: 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);
5324: 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);
5325: 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);
5326: 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);
5327: 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);
5328: 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);
5329: PetscFunctionReturn(PETSC_SUCCESS);
5330: }
5332: /*@
5333: SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5334: convergence criteria for the linear solvers within an inexact
5335: Newton method.
5337: Not Collective
5339: Input Parameter:
5340: . snes - `SNES` context
5342: Output Parameters:
5343: + version - version 1, 2 (default is 2), 3 or 4
5344: . rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5345: . rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5346: . gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5347: . alpha - power for version 2 rtol computation (1 < alpha <= 2)
5348: . alpha2 - power for safeguard
5349: - threshold - threshold for imposing safeguard (0 < threshold < 1)
5351: Level: advanced
5353: .seealso: [](ch_snes), `SNES`, `SNESKSPSetUseEW()`, `SNESKSPGetUseEW()`, `SNESKSPSetParametersEW()`
5354: @*/
5355: PetscErrorCode SNESKSPGetParametersEW(SNES snes, PetscInt *version, PetscReal *rtol_0, PetscReal *rtol_max, PetscReal *gamma, PetscReal *alpha, PetscReal *alpha2, PetscReal *threshold)
5356: {
5357: SNESKSPEW *kctx;
5359: PetscFunctionBegin;
5361: kctx = (SNESKSPEW *)snes->kspconvctx;
5362: PetscCheck(kctx, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "No Eisenstat-Walker context existing");
5363: if (version) *version = kctx->version;
5364: if (rtol_0) *rtol_0 = kctx->rtol_0;
5365: if (rtol_max) *rtol_max = kctx->rtol_max;
5366: if (gamma) *gamma = kctx->gamma;
5367: if (alpha) *alpha = kctx->alpha;
5368: if (alpha2) *alpha2 = kctx->alpha2;
5369: if (threshold) *threshold = kctx->threshold;
5370: PetscFunctionReturn(PETSC_SUCCESS);
5371: }
5373: PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5374: {
5375: SNES snes = (SNES)ctx;
5376: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5377: PetscReal rtol = PETSC_DEFAULT, stol;
5379: PetscFunctionBegin;
5380: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5381: if (!snes->iter) {
5382: rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5383: PetscCall(VecNorm(snes->vec_func, NORM_2, &kctx->norm_first));
5384: } else {
5385: PetscCheck(kctx->version >= 1 && kctx->version <= 4, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Only versions 1-4 are supported: %" PetscInt_FMT, kctx->version);
5386: if (kctx->version == 1) {
5387: rtol = PetscAbsReal(snes->norm - kctx->lresid_last) / kctx->norm_last;
5388: stol = PetscPowReal(kctx->rtol_last, kctx->alpha2);
5389: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5390: } else if (kctx->version == 2) {
5391: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5392: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5393: if (stol > kctx->threshold) rtol = PetscMax(rtol, stol);
5394: } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5395: rtol = kctx->gamma * PetscPowReal(snes->norm / kctx->norm_last, kctx->alpha);
5396: /* safeguard: avoid sharp decrease of rtol */
5397: stol = kctx->gamma * PetscPowReal(kctx->rtol_last, kctx->alpha);
5398: stol = PetscMax(rtol, stol);
5399: rtol = PetscMin(kctx->rtol_0, stol);
5400: /* safeguard: avoid oversolving */
5401: stol = kctx->gamma * (kctx->norm_first * snes->rtol) / snes->norm;
5402: stol = PetscMax(rtol, stol);
5403: rtol = PetscMin(kctx->rtol_0, stol);
5404: } else /* if (kctx->version == 4) */ {
5405: /* H.-B. An et al. Journal of Computational and Applied Mathematics 200 (2007) 47-60 */
5406: PetscReal ared = PetscAbsReal(kctx->norm_last - snes->norm);
5407: PetscReal pred = PetscAbsReal(kctx->norm_last - kctx->lresid_last);
5408: PetscReal rk = ared / pred;
5409: if (rk < kctx->v4_p1) rtol = 1. - 2. * kctx->v4_p1;
5410: else if (rk < kctx->v4_p2) rtol = kctx->rtol_last;
5411: else if (rk < kctx->v4_p3) rtol = kctx->v4_m1 * kctx->rtol_last;
5412: else rtol = kctx->v4_m2 * kctx->rtol_last;
5414: 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;
5415: kctx->rtol_last_2 = kctx->rtol_last;
5416: kctx->rk_last_2 = kctx->rk_last;
5417: kctx->rk_last = rk;
5418: }
5419: }
5420: /* safeguard: avoid rtol greater than rtol_max */
5421: rtol = PetscMin(rtol, kctx->rtol_max);
5422: PetscCall(KSPSetTolerances(ksp, rtol, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT));
5423: PetscCall(PetscInfo(snes, "iter %" PetscInt_FMT ", Eisenstat-Walker (version %" PetscInt_FMT ") KSP rtol=%g\n", snes->iter, kctx->version, (double)rtol));
5424: PetscFunctionReturn(PETSC_SUCCESS);
5425: }
5427: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, void *ctx)
5428: {
5429: SNES snes = (SNES)ctx;
5430: SNESKSPEW *kctx = (SNESKSPEW *)snes->kspconvctx;
5431: PCSide pcside;
5432: Vec lres;
5434: PetscFunctionBegin;
5435: if (!snes->ksp_ewconv) PetscFunctionReturn(PETSC_SUCCESS);
5436: PetscCall(KSPGetTolerances(ksp, &kctx->rtol_last, NULL, NULL, NULL));
5437: kctx->norm_last = snes->norm;
5438: if (kctx->version == 1 || kctx->version == 4) {
5439: PC pc;
5440: PetscBool getRes;
5442: PetscCall(KSPGetPC(ksp, &pc));
5443: PetscCall(PetscObjectTypeCompare((PetscObject)pc, PCNONE, &getRes));
5444: if (!getRes) {
5445: KSPNormType normtype;
5447: PetscCall(KSPGetNormType(ksp, &normtype));
5448: getRes = (PetscBool)(normtype == KSP_NORM_UNPRECONDITIONED);
5449: }
5450: PetscCall(KSPGetPCSide(ksp, &pcside));
5451: if (pcside == PC_RIGHT || getRes) { /* KSP residual is true linear residual */
5452: PetscCall(KSPGetResidualNorm(ksp, &kctx->lresid_last));
5453: } else {
5454: /* KSP residual is preconditioned residual */
5455: /* compute true linear residual norm */
5456: Mat J;
5457: PetscCall(KSPGetOperators(ksp, &J, NULL));
5458: PetscCall(VecDuplicate(b, &lres));
5459: PetscCall(MatMult(J, x, lres));
5460: PetscCall(VecAYPX(lres, -1.0, b));
5461: PetscCall(VecNorm(lres, NORM_2, &kctx->lresid_last));
5462: PetscCall(VecDestroy(&lres));
5463: }
5464: }
5465: PetscFunctionReturn(PETSC_SUCCESS);
5466: }
5468: /*@
5469: SNESGetKSP - Returns the `KSP` context for a `SNES` solver.
5471: Not Collective, but if `snes` is parallel, then `ksp` is parallel
5473: Input Parameter:
5474: . snes - the `SNES` context
5476: Output Parameter:
5477: . ksp - the `KSP` context
5479: Level: beginner
5481: Notes:
5482: The user can then directly manipulate the `KSP` context to set various
5483: options, etc. Likewise, the user can then extract and manipulate the
5484: `PC` contexts as well.
5486: Some `SNESType`s do not use a `KSP` but a `KSP` is still returned by this function
5488: .seealso: [](ch_snes), `SNES`, `KSP`, `PC`, `KSPGetPC()`, `SNESCreate()`, `KSPCreate()`, `SNESSetKSP()`
5489: @*/
5490: PetscErrorCode SNESGetKSP(SNES snes, KSP *ksp)
5491: {
5492: PetscFunctionBegin;
5494: PetscAssertPointer(ksp, 2);
5496: if (!snes->ksp) {
5497: PetscCall(KSPCreate(PetscObjectComm((PetscObject)snes), &snes->ksp));
5498: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->ksp, (PetscObject)snes, 1));
5500: PetscCall(KSPSetPreSolve(snes->ksp, KSPPreSolve_SNESEW, snes));
5501: PetscCall(KSPSetPostSolve(snes->ksp, KSPPostSolve_SNESEW, snes));
5503: PetscCall(KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes));
5504: PetscCall(PetscObjectSetOptions((PetscObject)snes->ksp, ((PetscObject)snes)->options));
5505: }
5506: *ksp = snes->ksp;
5507: PetscFunctionReturn(PETSC_SUCCESS);
5508: }
5510: #include <petsc/private/dmimpl.h>
5511: /*@
5512: SNESSetDM - Sets the `DM` that may be used by some nonlinear solvers or their underlying preconditioners
5514: Logically Collective
5516: Input Parameters:
5517: + snes - the nonlinear solver context
5518: - dm - the `DM`, cannot be `NULL`
5520: Level: intermediate
5522: Note:
5523: A `DM` can only be used for solving one problem at a time because information about the problem is stored on the `DM`,
5524: even when not using interfaces like `DMSNESSetFunction()`. Use `DMClone()` to get a distinct `DM` when solving different
5525: problems using the same function space.
5527: .seealso: [](ch_snes), `DM`, `SNES`, `SNESGetDM()`, `KSPSetDM()`, `KSPGetDM()`
5528: @*/
5529: PetscErrorCode SNESSetDM(SNES snes, DM dm)
5530: {
5531: KSP ksp;
5532: DMSNES sdm;
5534: PetscFunctionBegin;
5537: PetscCall(PetscObjectReference((PetscObject)dm));
5538: if (snes->dm) { /* Move the DMSNES context over to the new DM unless the new DM already has one */
5539: if (snes->dm->dmsnes && !dm->dmsnes) {
5540: PetscCall(DMCopyDMSNES(snes->dm, dm));
5541: PetscCall(DMGetDMSNES(snes->dm, &sdm));
5542: if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5543: }
5544: PetscCall(DMCoarsenHookRemove(snes->dm, DMCoarsenHook_SNESVecSol, DMRestrictHook_SNESVecSol, snes));
5545: PetscCall(DMDestroy(&snes->dm));
5546: }
5547: snes->dm = dm;
5548: snes->dmAuto = PETSC_FALSE;
5550: PetscCall(SNESGetKSP(snes, &ksp));
5551: PetscCall(KSPSetDM(ksp, dm));
5552: PetscCall(KSPSetDMActive(ksp, PETSC_FALSE));
5553: if (snes->npc) {
5554: PetscCall(SNESSetDM(snes->npc, snes->dm));
5555: PetscCall(SNESSetNPCSide(snes, snes->npcside));
5556: }
5557: PetscFunctionReturn(PETSC_SUCCESS);
5558: }
5560: /*@
5561: SNESGetDM - Gets the `DM` that may be used by some solvers/preconditioners
5563: Not Collective but dm obtained is parallel on snes
5565: Input Parameter:
5566: . snes - the `SNES` context
5568: Output Parameter:
5569: . dm - the `DM`
5571: Level: intermediate
5573: .seealso: [](ch_snes), `DM`, `SNES`, `SNESSetDM()`, `KSPSetDM()`, `KSPGetDM()`
5574: @*/
5575: PetscErrorCode SNESGetDM(SNES snes, DM *dm)
5576: {
5577: PetscFunctionBegin;
5579: if (!snes->dm) {
5580: PetscCall(DMShellCreate(PetscObjectComm((PetscObject)snes), &snes->dm));
5581: snes->dmAuto = PETSC_TRUE;
5582: }
5583: *dm = snes->dm;
5584: PetscFunctionReturn(PETSC_SUCCESS);
5585: }
5587: /*@
5588: SNESSetNPC - Sets the nonlinear preconditioner to be used.
5590: Collective
5592: Input Parameters:
5593: + snes - iterative context obtained from `SNESCreate()`
5594: - npc - the nonlinear preconditioner object
5596: Level: developer
5598: Notes:
5599: Use `SNESGetNPC()` to retrieve the preconditioner context (for example,
5600: to configure it using the API).
5602: Only some `SNESType` can use a nonlinear preconditioner
5604: .seealso: [](ch_snes), `SNES`, `SNESNGS`, `SNESFAS`, `SNESGetNPC()`, `SNESHasNPC()`
5605: @*/
5606: PetscErrorCode SNESSetNPC(SNES snes, SNES npc)
5607: {
5608: PetscFunctionBegin;
5611: PetscCheckSameComm(snes, 1, npc, 2);
5612: PetscCall(PetscObjectReference((PetscObject)npc));
5613: PetscCall(SNESDestroy(&snes->npc));
5614: snes->npc = npc;
5615: PetscFunctionReturn(PETSC_SUCCESS);
5616: }
5618: /*@
5619: SNESGetNPC - Gets a nonlinear preconditioning solver SNES` to be used to precondition the original nonlinear solver.
5621: Not Collective; but any changes to the obtained the npc object must be applied collectively
5623: Input Parameter:
5624: . snes - iterative context obtained from `SNESCreate()`
5626: Output Parameter:
5627: . pc - preconditioner context
5629: Options Database Key:
5630: . -npc_snes_type <type> - set the type of the `SNES` to use as the nonlinear preconditioner
5632: Level: developer
5634: Notes:
5635: If a `SNES` was previously set with `SNESSetNPC()` then that value is returned, otherwise a new `SNES` object is created.
5637: The (preconditioner) `SNES` returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5638: `SNES`
5640: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESHasNPC()`, `SNES`, `SNESCreate()`
5641: @*/
5642: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5643: {
5644: const char *optionsprefix;
5646: PetscFunctionBegin;
5648: PetscAssertPointer(pc, 2);
5649: if (!snes->npc) {
5650: void *ctx;
5652: PetscCall(SNESCreate(PetscObjectComm((PetscObject)snes), &snes->npc));
5653: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->npc, (PetscObject)snes, 1));
5654: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5655: PetscCall(SNESSetOptionsPrefix(snes->npc, optionsprefix));
5656: PetscCall(SNESAppendOptionsPrefix(snes->npc, "npc_"));
5657: if (snes->ops->usercompute) {
5658: PetscCall(SNESSetComputeApplicationContext(snes, snes->ops->usercompute, snes->ops->userdestroy));
5659: } else {
5660: PetscCall(SNESGetApplicationContext(snes, &ctx));
5661: PetscCall(SNESSetApplicationContext(snes->npc, ctx));
5662: }
5663: PetscCall(SNESSetCountersReset(snes->npc, PETSC_FALSE));
5664: }
5665: *pc = snes->npc;
5666: PetscFunctionReturn(PETSC_SUCCESS);
5667: }
5669: /*@
5670: SNESHasNPC - Returns whether a nonlinear preconditioner exists
5672: Not Collective
5674: Input Parameter:
5675: . snes - iterative context obtained from `SNESCreate()`
5677: Output Parameter:
5678: . has_npc - whether the `SNES` has a nonlinear preconditioner or not
5680: Level: developer
5682: .seealso: [](ch_snes), `SNESSetNPC()`, `SNESGetNPC()`
5683: @*/
5684: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5685: {
5686: PetscFunctionBegin;
5688: *has_npc = (PetscBool)(snes->npc ? PETSC_TRUE : PETSC_FALSE);
5689: PetscFunctionReturn(PETSC_SUCCESS);
5690: }
5692: /*@
5693: SNESSetNPCSide - Sets the nonlinear preconditioning side.
5695: Logically Collective
5697: Input Parameter:
5698: . snes - iterative context obtained from `SNESCreate()`
5700: Output Parameter:
5701: . side - the preconditioning side, where side is one of
5702: .vb
5703: PC_LEFT - left preconditioning
5704: PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5705: .ve
5707: Options Database Key:
5708: . -snes_npc_side <right,left> - nonlinear preconditioner side
5710: Level: intermediate
5712: Note:
5713: `SNESNRICHARDSON` and `SNESNCG` only support left preconditioning.
5715: .seealso: [](ch_snes), `SNES`, `SNESNRICHARDSON`, `SNESNCG`, `SNESType`, `SNESGetNPCSide()`, `KSPSetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5716: @*/
5717: PetscErrorCode SNESSetNPCSide(SNES snes, PCSide side)
5718: {
5719: PetscFunctionBegin;
5722: if (side == PC_SIDE_DEFAULT) side = PC_RIGHT;
5723: PetscCheck((side == PC_LEFT) || (side == PC_RIGHT), PetscObjectComm((PetscObject)snes), PETSC_ERR_ARG_WRONG, "Only PC_LEFT and PC_RIGHT are supported");
5724: snes->npcside = side;
5725: PetscFunctionReturn(PETSC_SUCCESS);
5726: }
5728: /*@
5729: SNESGetNPCSide - Gets the preconditioning side.
5731: Not Collective
5733: Input Parameter:
5734: . snes - iterative context obtained from `SNESCreate()`
5736: Output Parameter:
5737: . side - the preconditioning side, where side is one of
5738: .vb
5739: `PC_LEFT` - left preconditioning
5740: `PC_RIGHT` - right preconditioning (default for most nonlinear solvers)
5741: .ve
5743: Level: intermediate
5745: .seealso: [](ch_snes), `SNES`, `SNESSetNPCSide()`, `KSPGetPCSide()`, `PC_LEFT`, `PC_RIGHT`, `PCSide`
5746: @*/
5747: PetscErrorCode SNESGetNPCSide(SNES snes, PCSide *side)
5748: {
5749: PetscFunctionBegin;
5751: PetscAssertPointer(side, 2);
5752: *side = snes->npcside;
5753: PetscFunctionReturn(PETSC_SUCCESS);
5754: }
5756: /*@
5757: SNESSetLineSearch - Sets the linesearch to be used for `SNES`
5759: Collective
5761: Input Parameters:
5762: + snes - iterative context obtained from `SNESCreate()`
5763: - linesearch - the linesearch object
5765: Level: developer
5767: Note:
5768: This is almost never used, rather one uses `SNESGetLineSearch()` to retrieve the line search and set options on it
5769: to configure it using the API).
5771: .seealso: [](ch_snes), `SNES`, `SNESLineSearch`, `SNESGetLineSearch()`
5772: @*/
5773: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5774: {
5775: PetscFunctionBegin;
5778: PetscCheckSameComm(snes, 1, linesearch, 2);
5779: PetscCall(PetscObjectReference((PetscObject)linesearch));
5780: PetscCall(SNESLineSearchDestroy(&snes->linesearch));
5782: snes->linesearch = linesearch;
5783: PetscFunctionReturn(PETSC_SUCCESS);
5784: }
5786: /*@
5787: SNESGetLineSearch - Returns the line search context possibly set with `SNESSetLineSearch()`
5788: or creates a default line search instance associated with the `SNES` and returns it.
5790: Not Collective
5792: Input Parameter:
5793: . snes - iterative context obtained from `SNESCreate()`
5795: Output Parameter:
5796: . linesearch - linesearch context
5798: Level: beginner
5800: .seealso: [](ch_snes), `SNESLineSearch`, `SNESSetLineSearch()`, `SNESLineSearchCreate()`
5801: @*/
5802: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5803: {
5804: const char *optionsprefix;
5806: PetscFunctionBegin;
5808: PetscAssertPointer(linesearch, 2);
5809: if (!snes->linesearch) {
5810: PetscCall(SNESGetOptionsPrefix(snes, &optionsprefix));
5811: PetscCall(SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch));
5812: PetscCall(SNESLineSearchSetSNES(snes->linesearch, snes));
5813: PetscCall(SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix));
5814: PetscCall(PetscObjectIncrementTabLevel((PetscObject)snes->linesearch, (PetscObject)snes, 1));
5815: }
5816: *linesearch = snes->linesearch;
5817: PetscFunctionReturn(PETSC_SUCCESS);
5818: }