Actual source code: snes.c

petsc-dev 2014-02-02
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  2: #include <petsc-private/snesimpl.h>      /*I "petscsnes.h"  I*/
  3: #include <petscdmshell.h>

  5: PetscBool         SNESRegisterAllCalled = PETSC_FALSE;
  6: PetscFunctionList SNESList              = NULL;

  8: /* Logging support */
  9: PetscClassId  SNES_CLASSID, DMSNES_CLASSID;
 10: PetscLogEvent SNES_Solve, SNES_FunctionEval, SNES_JacobianEval, SNES_GSEval, SNES_GSFuncEval, SNES_NPCSolve;

 14: /*@
 15:    SNESSetErrorIfNotConverged - Causes SNESSolve() to generate an error if the solver has not converged.

 17:    Logically Collective on SNES

 19:    Input Parameters:
 20: +  snes - iterative context obtained from SNESCreate()
 21: -  flg - PETSC_TRUE indicates you want the error generated

 23:    Options database keys:
 24: .  -snes_error_if_not_converged : this takes an optional truth value (0/1/no/yes/true/false)

 26:    Level: intermediate

 28:    Notes:
 29:     Normally PETSc continues if a linear solver fails to converge, you can call SNESGetConvergedReason() after a SNESSolve()
 30:     to determine if it has converged.

 32: .keywords: SNES, set, initial guess, nonzero

 34: .seealso: SNESGetErrorIfNotConverged(), KSPGetErrorIfNotConverged(), KSPSetErrorIFNotConverged()
 35: @*/
 36: PetscErrorCode  SNESSetErrorIfNotConverged(SNES snes,PetscBool flg)
 37: {
 41:   snes->errorifnotconverged = flg;
 42:   return(0);
 43: }

 47: /*@
 48:    SNESGetErrorIfNotConverged - Will SNESSolve() generate an error if the solver does not converge?

 50:    Not Collective

 52:    Input Parameter:
 53: .  snes - iterative context obtained from SNESCreate()

 55:    Output Parameter:
 56: .  flag - PETSC_TRUE if it will generate an error, else PETSC_FALSE

 58:    Level: intermediate

 60: .keywords: SNES, set, initial guess, nonzero

 62: .seealso:  SNESSetErrorIfNotConverged(), KSPGetErrorIfNotConverged(), KSPSetErrorIFNotConverged()
 63: @*/
 64: PetscErrorCode  SNESGetErrorIfNotConverged(SNES snes,PetscBool  *flag)
 65: {
 69:   *flag = snes->errorifnotconverged;
 70:   return(0);
 71: }

 75: /*@
 76:    SNESSetFunctionDomainError - tells SNES that the input vector to your SNESFunction is not
 77:      in the functions domain. For example, negative pressure.

 79:    Logically Collective on SNES

 81:    Input Parameters:
 82: .  snes - the SNES context

 84:    Level: advanced

 86: .keywords: SNES, view

 88: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction
 89: @*/
 90: PetscErrorCode  SNESSetFunctionDomainError(SNES snes)
 91: {
 94:   snes->domainerror = PETSC_TRUE;
 95:   return(0);
 96: }

100: /*@
101:    SNESGetFunctionDomainError - Gets the status of the domain error after a call to SNESComputeFunction;

103:    Logically Collective on SNES

105:    Input Parameters:
106: .  snes - the SNES context

108:    Output Parameters:
109: .  domainerror - Set to PETSC_TRUE if there's a domain error; PETSC_FALSE otherwise.

111:    Level: advanced

113: .keywords: SNES, view

115: .seealso: SNESSetFunctionDomainError(), SNESComputeFunction()
116: @*/
117: PetscErrorCode  SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
118: {
122:   *domainerror = snes->domainerror;
123:   return(0);
124: }

128: /*@C
129:   SNESLoad - Loads a SNES that has been stored in binary  with SNESView().

131:   Collective on PetscViewer

133:   Input Parameters:
134: + newdm - the newly loaded SNES, this needs to have been created with SNESCreate() or
135:            some related function before a call to SNESLoad().
136: - viewer - binary file viewer, obtained from PetscViewerBinaryOpen()

138:    Level: intermediate

140:   Notes:
141:    The type is determined by the data in the file, any type set into the SNES before this call is ignored.

143:   Notes for advanced users:
144:   Most users should not need to know the details of the binary storage
145:   format, since SNESLoad() and TSView() completely hide these details.
146:   But for anyone who's interested, the standard binary matrix storage
147:   format is
148: .vb
149:      has not yet been determined
150: .ve

152: .seealso: PetscViewerBinaryOpen(), SNESView(), MatLoad(), VecLoad()
153: @*/
154: PetscErrorCode  SNESLoad(SNES snes, PetscViewer viewer)
155: {
157:   PetscBool      isbinary;
158:   PetscInt       classid;
159:   char           type[256];
160:   KSP            ksp;
161:   DM             dm;
162:   DMSNES         dmsnes;

167:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
168:   if (!isbinary) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");

170:   PetscViewerBinaryRead(viewer,&classid,1,PETSC_INT);
171:   if (classid != SNES_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONG,"Not SNES next in file");
172:   PetscViewerBinaryRead(viewer,type,256,PETSC_CHAR);
173:   SNESSetType(snes, type);
174:   if (snes->ops->load) {
175:     (*snes->ops->load)(snes,viewer);
176:   }
177:   SNESGetDM(snes,&dm);
178:   DMGetDMSNES(dm,&dmsnes);
179:   DMSNESLoad(dmsnes,viewer);
180:   SNESGetKSP(snes,&ksp);
181:   KSPLoad(ksp,viewer);
182:   return(0);
183: }

185: #include <petscdraw.h>
186: #if defined(PETSC_HAVE_SAWS)
187: #include <petscviewersaws.h>
188: #endif
191: /*@C
192:    SNESView - Prints the SNES data structure.

194:    Collective on SNES

196:    Input Parameters:
197: +  SNES - the SNES context
198: -  viewer - visualization context

200:    Options Database Key:
201: .  -snes_view - Calls SNESView() at end of SNESSolve()

203:    Notes:
204:    The available visualization contexts include
205: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
206: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
207:          output where only the first processor opens
208:          the file.  All other processors send their
209:          data to the first processor to print.

211:    The user can open an alternative visualization context with
212:    PetscViewerASCIIOpen() - output to a specified file.

214:    Level: beginner

216: .keywords: SNES, view

218: .seealso: PetscViewerASCIIOpen()
219: @*/
220: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
221: {
222:   SNESKSPEW      *kctx;
224:   KSP            ksp;
225:   SNESLineSearch linesearch;
226:   PetscBool      iascii,isstring,isbinary,isdraw;
227:   DMSNES         dmsnes;
228: #if defined(PETSC_HAVE_SAWS)
229:   PetscBool      isams;
230: #endif

234:   if (!viewer) {
235:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&viewer);
236:   }

240:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
241:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
242:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
243:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
244: #if defined(PETSC_HAVE_SAWS)
245:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&isams);
246: #endif
247:   if (iascii) {
248:     PetscObjectPrintClassNamePrefixType((PetscObject)snes,viewer);
249:     if (!snes->setupcalled) {
250:       PetscViewerASCIIPrintf(viewer,"  SNES has not been set up so information may be incomplete\n");
251:     }
252:     if (snes->ops->view) {
253:       PetscViewerASCIIPushTab(viewer);
254:       (*snes->ops->view)(snes,viewer);
255:       PetscViewerASCIIPopTab(viewer);
256:     }
257:     PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
258:     PetscViewerASCIIPrintf(viewer,"  tolerances: relative=%g, absolute=%g, solution=%g\n",(double)snes->rtol,(double)snes->abstol,(double)snes->stol);
259:     PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",snes->linear_its);
260:     PetscViewerASCIIPrintf(viewer,"  total number of function evaluations=%D\n",snes->nfuncs);
261:     if (snes->gridsequence) {
262:       PetscViewerASCIIPrintf(viewer,"  total number of grid sequence refinements=%D\n",snes->gridsequence);
263:     }
264:     if (snes->ksp_ewconv) {
265:       kctx = (SNESKSPEW*)snes->kspconvctx;
266:       if (kctx) {
267:         PetscViewerASCIIPrintf(viewer,"  Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
268:         PetscViewerASCIIPrintf(viewer,"    rtol_0=%g, rtol_max=%g, threshold=%g\n",(double)kctx->rtol_0,(double)kctx->rtol_max,(double)kctx->threshold);
269:         PetscViewerASCIIPrintf(viewer,"    gamma=%g, alpha=%g, alpha2=%g\n",(double)kctx->gamma,(double)kctx->alpha,(double)kctx->alpha2);
270:       }
271:     }
272:     if (snes->lagpreconditioner == -1) {
273:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is never rebuilt\n");
274:     } else if (snes->lagpreconditioner > 1) {
275:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is rebuilt every %D new Jacobians\n",snes->lagpreconditioner);
276:     }
277:     if (snes->lagjacobian == -1) {
278:       PetscViewerASCIIPrintf(viewer,"  Jacobian is never rebuilt\n");
279:     } else if (snes->lagjacobian > 1) {
280:       PetscViewerASCIIPrintf(viewer,"  Jacobian is rebuilt every %D SNES iterations\n",snes->lagjacobian);
281:     }
282:   } else if (isstring) {
283:     const char *type;
284:     SNESGetType(snes,&type);
285:     PetscViewerStringSPrintf(viewer," %-3.3s",type);
286:   } else if (isbinary) {
287:     PetscInt    classid = SNES_FILE_CLASSID;
288:     MPI_Comm    comm;
289:     PetscMPIInt rank;
290:     char        type[256];

292:     PetscObjectGetComm((PetscObject)snes,&comm);
293:     MPI_Comm_rank(comm,&rank);
294:     if (!rank) {
295:       PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);
296:       PetscStrncpy(type,((PetscObject)snes)->type_name,256);
297:       PetscViewerBinaryWrite(viewer,type,256,PETSC_CHAR,PETSC_FALSE);
298:     }
299:     if (snes->ops->view) {
300:       (*snes->ops->view)(snes,viewer);
301:     }
302:   } else if (isdraw) {
303:     PetscDraw draw;
304:     char      str[36];
305:     PetscReal x,y,bottom,h;

307:     PetscViewerDrawGetDraw(viewer,0,&draw);
308:     PetscDrawGetCurrentPoint(draw,&x,&y);
309:     PetscStrcpy(str,"SNES: ");
310:     PetscStrcat(str,((PetscObject)snes)->type_name);
311:     PetscDrawBoxedString(draw,x,y,PETSC_DRAW_BLUE,PETSC_DRAW_BLACK,str,NULL,&h);
312:     bottom = y - h;
313:     PetscDrawPushCurrentPoint(draw,x,bottom);
314:     if (snes->ops->view) {
315:       (*snes->ops->view)(snes,viewer);
316:     }
317: #if defined(PETSC_HAVE_SAWS)
318:   } else if (isams) {
319:     PetscMPIInt rank;
320:     const char *name;

322:     PetscObjectGetName((PetscObject)snes,&name);
323:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
324:     if (!((PetscObject)snes)->amsmem && !rank) {
325:       char       dir[1024];

327:       PetscObjectViewSAWs((PetscObject)snes,viewer);
328:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
329:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
330:       if (!snes->conv_hist) {
331:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
332:       }
333:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
334:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
335:     }
336: #endif
337:   }
338:   if (snes->linesearch) {
339:     PetscViewerASCIIPushTab(viewer);
340:     SNESGetLineSearch(snes, &linesearch);
341:     SNESLineSearchView(linesearch, viewer);
342:     PetscViewerASCIIPopTab(viewer);
343:   }
344:   if (snes->pc && snes->usespc) {
345:     PetscViewerASCIIPushTab(viewer);
346:     SNESView(snes->pc, viewer);
347:     PetscViewerASCIIPopTab(viewer);
348:   }
349:   PetscViewerASCIIPushTab(viewer);
350:   DMGetDMSNES(snes->dm,&dmsnes);
351:   DMSNESView(dmsnes, viewer);
352:   PetscViewerASCIIPopTab(viewer);
353:   if (snes->usesksp) {
354:     SNESGetKSP(snes,&ksp);
355:     PetscViewerASCIIPushTab(viewer);
356:     KSPView(ksp,viewer);
357:     PetscViewerASCIIPopTab(viewer);
358:   }
359:   if (isdraw) {
360:     PetscDraw draw;
361:     PetscViewerDrawGetDraw(viewer,0,&draw);
362:     PetscDrawPopCurrentPoint(draw);
363:   }
364:   return(0);
365: }

367: /*
368:   We retain a list of functions that also take SNES command
369:   line options. These are called at the end SNESSetFromOptions()
370: */
371: #define MAXSETFROMOPTIONS 5
372: static PetscInt numberofsetfromoptions;
373: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

377: /*@C
378:   SNESAddOptionsChecker - Adds an additional function to check for SNES options.

380:   Not Collective

382:   Input Parameter:
383: . snescheck - function that checks for options

385:   Level: developer

387: .seealso: SNESSetFromOptions()
388: @*/
389: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
390: {
392:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
393:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
394:   return(0);
395: }

397: extern PetscErrorCode  SNESDefaultMatrixFreeCreate2(SNES,Vec,Mat*);

401: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
402: {
403:   Mat            J;
404:   KSP            ksp;
405:   PC             pc;
406:   PetscBool      match;


412:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
413:     Mat A = snes->jacobian, B = snes->jacobian_pre;
414:     MatGetVecs(A ? A : B, NULL,&snes->vec_func);
415:   }

417:   if (version == 1) {
418:     MatCreateSNESMF(snes,&J);
419:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
420:     MatSetFromOptions(J);
421:   } else if (version == 2) {
422:     if (!snes->vec_func) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first");
423: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128)
424:     SNESDefaultMatrixFreeCreate2(snes,snes->vec_func,&J);
425: #else
426:     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP, "matrix-free operator rutines (version 2)");
427: #endif
428:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator rutines, only version 1 and 2");

430:   PetscInfo1(snes,"Setting default matrix-free operator routines (version %D)\n", version);
431:   if (hasOperator) {

433:     /* This version replaces the user provided Jacobian matrix with a
434:        matrix-free version but still employs the user-provided preconditioner matrix. */
435:     SNESSetJacobian(snes,J,0,0,0);
436:   } else {
437:     /* This version replaces both the user-provided Jacobian and the user-
438:      provided preconditioner Jacobian with the default matrix free version. */
439:     if ((snes->pcside == PC_LEFT) && snes->pc) {
440:       if (!snes->jacobian){SNESSetJacobian(snes,J,0,0,0);}
441:     } else {
442:       SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,0);
443:     }
444:     /* Force no preconditioner */
445:     SNESGetKSP(snes,&ksp);
446:     KSPGetPC(ksp,&pc);
447:     PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&match);
448:     if (!match) {
449:       PetscInfo(snes,"Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n");
450:       PCSetType(pc,PCNONE);
451:     }
452:   }
453:   MatDestroy(&J);
454:   return(0);
455: }

459: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
460: {
461:   SNES           snes = (SNES)ctx;
463:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

466:   if (PetscLogPrintInfo) {
467:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
468:     DMGetRefineLevel(dmfine,&finelevel);
469:     DMGetCoarsenLevel(dmfine,&fineclevel);
470:     DMGetRefineLevel(dmcoarse,&coarselevel);
471:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
472:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
473:   }
474:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
475:   else {
476:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
477:     Xfine = Xfine_named;
478:   }
479:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
480:   MatRestrict(Restrict,Xfine,Xcoarse);
481:   VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
482:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
483:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
484:   return(0);
485: }

489: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
490: {

494:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
495:   return(0);
496: }

500: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
501:  * safely call SNESGetDM() in their residual evaluation routine. */
502: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,MatStructure *mstruct,void *ctx)
503: {
504:   SNES           snes = (SNES)ctx;
506:   Mat            Asave = A,Bsave = B;
507:   Vec            X,Xnamed = NULL;
508:   DM             dmsave;
509:   void           *ctxsave;
510:   PetscErrorCode (*jac)(SNES,Vec,Mat*,Mat*,MatStructure*,void*);

513:   dmsave = snes->dm;
514:   KSPGetDM(ksp,&snes->dm);
515:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
516:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
517:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
518:     X    = Xnamed;
519:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
520:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
521:     if (jac == SNESComputeJacobianDefaultColor) {
522:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,0);
523:     }
524:   }
525:   /* put the previous context back */

527:   SNESComputeJacobian(snes,X,&A,&B,mstruct);
528:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
529:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
530:   }

532:   if (A != Asave || B != Bsave) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_SUP,"No support for changing matrices at this time");
533:   if (Xnamed) {
534:     DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
535:   }
536:   snes->dm = dmsave;
537:   return(0);
538: }

542: /*@
543:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

545:    Collective

547:    Input Arguments:
548: .  snes - snes to configure

550:    Level: developer

552: .seealso: SNESSetUp()
553: @*/
554: PetscErrorCode SNESSetUpMatrices(SNES snes)
555: {
557:   DM             dm;
558:   DMSNES         sdm;

561:   SNESGetDM(snes,&dm);
562:   DMGetDMSNES(dm,&sdm);
563:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_PLIB,"DMSNES not properly configured");
564:   else if (!snes->jacobian && snes->mf) {
565:     Mat  J;
566:     void *functx;
567:     MatCreateSNESMF(snes,&J);
568:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
569:     MatSetFromOptions(J);
570:     SNESGetFunction(snes,NULL,NULL,&functx);
571:     SNESSetJacobian(snes,J,J,0,0);
572:     MatDestroy(&J);
573:   } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
574:     Mat J,B;
575:     MatCreateSNESMF(snes,&J);
576:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
577:     MatSetFromOptions(J);
578:     DMCreateMatrix(snes->dm,&B);
579:     /* sdm->computejacobian was already set to reach here */
580:     SNESSetJacobian(snes,J,B,NULL,NULL);
581:     MatDestroy(&J);
582:     MatDestroy(&B);
583:   } else if (!snes->jacobian_pre) {
584:     Mat J,B;
585:     J    = snes->jacobian;
586:     DMCreateMatrix(snes->dm,&B);
587:     SNESSetJacobian(snes,J ? J : B,B,NULL,NULL);
588:     MatDestroy(&B);
589:   }
590:   {
591:     KSP ksp;
592:     SNESGetKSP(snes,&ksp);
593:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
594:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
595:   }
596:   return(0);
597: }

601: /*@
602:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

604:    Collective on SNES

606:    Input Parameter:
607: .  snes - the SNES context

609:    Options Database Keys:
610: +  -snes_type <type> - ls, tr, ngmres, ncg, richardson, qn, vi, fas
611: .  -snes_stol - convergence tolerance in terms of the norm
612:                 of the change in the solution between steps
613: .  -snes_atol <abstol> - absolute tolerance of residual norm
614: .  -snes_rtol <rtol> - relative decrease in tolerance norm from initial
615: .  -snes_max_it <max_it> - maximum number of iterations
616: .  -snes_max_funcs <max_funcs> - maximum number of function evaluations
617: .  -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
618: .  -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
619: .  -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
620: .  -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
621: .  -snes_trtol <trtol> - trust region tolerance
622: .  -snes_no_convergence_test - skip convergence test in nonlinear
623:                                solver; hence iterations will continue until max_it
624:                                or some other criterion is reached. Saves expense
625:                                of convergence test
626: .  -snes_monitor <optional filename> - prints residual norm at each iteration. if no
627:                                        filename given prints to stdout
628: .  -snes_monitor_solution - plots solution at each iteration
629: .  -snes_monitor_residual - plots residual (not its norm) at each iteration
630: .  -snes_monitor_solution_update - plots update to solution at each iteration
631: .  -snes_monitor_lg_residualnorm - plots residual norm at each iteration
632: .  -snes_monitor_lg_range - plots residual norm at each iteration
633: .  -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
634: .  -snes_fd_color - use finite differences with coloring to compute Jacobian
635: .  -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
636: -  -snes_converged_reason - print the reason for convergence/divergence after each solve

638:     Options Database for Eisenstat-Walker method:
639: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
640: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
641: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
642: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
643: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
644: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
645: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
646: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

648:    Notes:
649:    To see all options, run your program with the -help option or consult
650:    the <A href="../../docs/manual.pdf#nameddest=ch_snes">SNES chapter of the users manual</A>.

652:    Level: beginner

654: .keywords: SNES, nonlinear, set, options, database

656: .seealso: SNESSetOptionsPrefix()
657: @*/
658: PetscErrorCode  SNESSetFromOptions(SNES snes)
659: {
660:   PetscBool      flg,pcset,persist;
661:   PetscInt       i,indx,lag,grids;
662:   MatStructure   matflag;
663:   const char     *deft        = SNESNEWTONLS;
664:   const char     *convtests[] = {"default","skip"};
665:   SNESKSPEW      *kctx        = NULL;
666:   char           type[256], monfilename[PETSC_MAX_PATH_LEN];
667:   PetscViewer    monviewer;
669:   PCSide         pcside;
670:   const char     *optionsprefix;

674:   if (!SNESRegisterAllCalled) {SNESRegisterAll();}
675:   PetscObjectOptionsBegin((PetscObject)snes);
676:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
677:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
678:   if (flg) {
679:     SNESSetType(snes,type);
680:   } else if (!((PetscObject)snes)->type_name) {
681:     SNESSetType(snes,deft);
682:   }
683:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,0);
684:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,0);

686:   PetscOptionsReal("-snes_rtol","Stop if decrease in function norm less than","SNESSetTolerances",snes->rtol,&snes->rtol,0);
687:   PetscOptionsInt("-snes_max_it","Maximum iterations","SNESSetTolerances",snes->max_its,&snes->max_its,NULL);
688:   PetscOptionsInt("-snes_max_funcs","Maximum function evaluations","SNESSetTolerances",snes->max_funcs,&snes->max_funcs,NULL);
689:   PetscOptionsInt("-snes_max_fail","Maximum nonlinear step failures","SNESSetMaxNonlinearStepFailures",snes->maxFailures,&snes->maxFailures,NULL);
690:   PetscOptionsInt("-snes_max_linear_solve_fail","Maximum failures in linear solves allowed","SNESSetMaxLinearSolveFailures",snes->maxLinearSolveFailures,&snes->maxLinearSolveFailures,NULL);
691:   PetscOptionsBool("-snes_error_if_not_converged","Generate error if solver does not converge","SNESSetErrorIfNotConverged",snes->errorifnotconverged,&snes->errorifnotconverged,NULL);

693:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
694:   if (flg) {
695:     SNESSetLagPreconditioner(snes,lag);
696:   }
697:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
698:   if (flg) {
699:     SNESSetLagPreconditionerPersists(snes,persist);
700:   }
701:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
702:   if (flg) {
703:     SNESSetLagJacobian(snes,lag);
704:   }
705:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
706:   if (flg) {
707:     SNESSetLagJacobianPersists(snes,persist);
708:   }

710:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
711:   if (flg) {
712:     SNESSetGridSequence(snes,grids);
713:   }

715:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,2,"default",&indx,&flg);
716:   if (flg) {
717:     switch (indx) {
718:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
719:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL);    break;
720:     }
721:   }

723:   PetscOptionsBool("-snes_converged_reason","Print reason for converged or diverged","SNESSolve",snes->printreason,&snes->printreason,NULL);

725:   PetscOptionsEList("-snes_norm_schedule","SNES Norm schedule","SNESSetNormSchedule",SNESNormSchedules,5,"function",&indx,&flg);
726:   if (flg) { SNESSetNormSchedule(snes,(SNESNormSchedule)indx); }

728:   PetscOptionsEList("-snes_function_type","SNES Norm schedule","SNESSetFunctionType",SNESFunctionTypes,2,"unpreconditioned",&indx,&flg);
729:   if (flg) { SNESSetFunctionType(snes,(SNESFunctionType)indx); }

731:   kctx = (SNESKSPEW*)snes->kspconvctx;

733:   PetscOptionsBool("-snes_ksp_ew","Use Eisentat-Walker linear system convergence test","SNESKSPSetUseEW",snes->ksp_ewconv,&snes->ksp_ewconv,NULL);

735:   PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,0);
736:   PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,0);
737:   PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,0);
738:   PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,0);
739:   PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,0);
740:   PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,0);
741:   PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",kctx->threshold,&kctx->threshold,0);

743:   flg  = PETSC_FALSE;
744:   PetscOptionsBool("-snes_check_jacobian","Check each Jacobian with a differenced one","SNESUpdateCheckJacobian",flg,&flg,NULL);
745:   if (flg) {
746:     SNESSetUpdate(snes,SNESUpdateCheckJacobian);
747:   }

749:   flg  = PETSC_FALSE;
750:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,NULL);
751:   if (flg) {SNESMonitorCancel(snes);}

753:   PetscOptionsString("-snes_monitor","Monitor norm of function","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
754:   if (flg) {
755:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
756:     SNESMonitorSet(snes,SNESMonitorDefault,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);
757:   }

759:   PetscOptionsString("-snes_monitor_range","Monitor range of elements of function","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
760:   if (flg) {
761:     SNESMonitorSet(snes,SNESMonitorRange,0,0);
762:   }

764:   PetscOptionsString("-snes_ratiomonitor","Monitor ratios of norms of function","SNESMonitorSetRatio","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
765:   if (flg) {
766:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
767:     SNESMonitorSetRatio(snes,monviewer);
768:   }

770:   PetscOptionsString("-snes_monitor_short","Monitor norm of function (fewer digits)","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
771:   if (flg) {
772:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
773:     SNESMonitorSet(snes,SNESMonitorDefaultShort,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);
774:   }

776:   PetscOptionsString("-snes_monitor_python","Use Python function","SNESMonitorSet",0,monfilename,PETSC_MAX_PATH_LEN,&flg);
777:   if (flg) {PetscPythonMonitorSet((PetscObject)snes,monfilename);}

779:   flg  = PETSC_FALSE;
780:   PetscOptionsBool("-snes_monitor_solution","Plot solution at each iteration","SNESMonitorSolution",flg,&flg,NULL);
781:   if (flg) {SNESMonitorSet(snes,SNESMonitorSolution,0,0);}
782:   flg  = PETSC_FALSE;
783:   PetscOptionsBool("-snes_monitor_solution_update","Plot correction at each iteration","SNESMonitorSolutionUpdate",flg,&flg,NULL);
784:   if (flg) {SNESMonitorSet(snes,SNESMonitorSolutionUpdate,0,0);}
785:   flg  = PETSC_FALSE;
786:   PetscOptionsBool("-snes_monitor_residual","Plot residual at each iteration","SNESMonitorResidual",flg,&flg,NULL);
787:   if (flg) {SNESMonitorSet(snes,SNESMonitorResidual,0,0);}
788:   flg  = PETSC_FALSE;
789:   PetscOptionsBool("-snes_monitor_lg_residualnorm","Plot function norm at each iteration","SNESMonitorLGResidualNorm",flg,&flg,NULL);
790:   if (flg) {
791:     PetscDrawLG ctx;

793:     SNESMonitorLGCreate(0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,&ctx);
794:     SNESMonitorSet(snes,SNESMonitorLGResidualNorm,ctx,(PetscErrorCode (*)(void**))SNESMonitorLGDestroy);
795:   }
796:   flg  = PETSC_FALSE;
797:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
798:   if (flg) {
799:     PetscViewer ctx;

801:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,&ctx);
802:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
803:   }

805:   flg  = PETSC_FALSE;
806:   PetscOptionsBool("-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",flg,&flg,NULL);
807:   if (flg) {SNESMonitorSet(snes,SNESMonitorJacUpdateSpectrum,0,0);}

809:   flg  = PETSC_FALSE;
810:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
811:   if (flg) {
812:     void *functx;
813:     SNESGetFunction(snes,NULL,NULL,&functx);
814:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
815:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
816:   }

818:   flg  = PETSC_FALSE;
819:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
820:   if (flg) {
821:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
822:   }

824:   flg  = PETSC_FALSE;
825:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
826:   if (flg) {
827:     DM             dm;
828:     DMSNES         sdm;
829:     SNESGetDM(snes,&dm);
830:     DMGetDMSNES(dm,&sdm);
831:     sdm->jacobianctx = NULL;
832:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,0);
833:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
834:   }

836:   flg  = PETSC_FALSE;
837:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","MatCreateSNESMF",PETSC_FALSE,&snes->mf_operator,&flg);
838:   if (flg && snes->mf_operator) {
839:     snes->mf_operator = PETSC_TRUE;
840:     snes->mf          = PETSC_TRUE;
841:   }
842:   flg  = PETSC_FALSE;
843:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","MatCreateSNESMF",PETSC_FALSE,&snes->mf,&flg);
844:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
845:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,0);

847:   flg  = PETSC_FALSE;
848:   SNESGetPCSide(snes,&pcside);
849:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
850:   if (flg) {SNESSetPCSide(snes,pcside);}

852: #if defined(PETSC_HAVE_SAWS)
853:   /*
854:     Publish convergence information using SAWs
855:   */
856:   flg  = PETSC_FALSE;
857:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
858:   if (flg) {
859:     void *ctx;
860:     SNESMonitorSAWsCreate(snes,&ctx);
861:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
862:   }
863: #endif
864: #if defined(PETSC_HAVE_SAWS)
865:   {
866:   PetscBool set;
867:   flg  = PETSC_FALSE;
868:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
869:   if (set) {
870:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
871:   }
872:   }
873: #endif

875:   for (i = 0; i < numberofsetfromoptions; i++) {
876:     (*othersetfromoptions[i])(snes);
877:   }

879:   if (snes->ops->setfromoptions) {
880:     (*snes->ops->setfromoptions)(snes);
881:   }

883:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
884:   PetscObjectProcessOptionsHandlers((PetscObject)snes);
885:   PetscOptionsEnd();

887:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
888:   KSPGetOperators(snes->ksp,NULL,NULL,&matflag);
889:   KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre,matflag);
890:   KSPSetFromOptions(snes->ksp);

892:   if (!snes->linesearch) {
893:     SNESGetLineSearch(snes, &snes->linesearch);
894:   }
895:   SNESLineSearchSetFromOptions(snes->linesearch);

897:   /* if someone has set the SNES PC type, create it. */
898:   SNESGetOptionsPrefix(snes, &optionsprefix);
899:   PetscOptionsHasName(optionsprefix, "-npc_snes_type", &pcset);
900:   if (pcset && (!snes->pc)) {
901:     SNESGetPC(snes, &snes->pc);
902:   }
903:   return(0);
904: }

908: /*@C
909:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
910:    the nonlinear solvers.

912:    Logically Collective on SNES

914:    Input Parameters:
915: +  snes - the SNES context
916: .  compute - function to compute the context
917: -  destroy - function to destroy the context

919:    Level: intermediate

921:    Notes:
922:    This function is currently not available from Fortran.

924: .keywords: SNES, nonlinear, set, application, context

926: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
927: @*/
928: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
929: {
932:   snes->ops->usercompute = compute;
933:   snes->ops->userdestroy = destroy;
934:   return(0);
935: }

939: /*@
940:    SNESSetApplicationContext - Sets the optional user-defined context for
941:    the nonlinear solvers.

943:    Logically Collective on SNES

945:    Input Parameters:
946: +  snes - the SNES context
947: -  usrP - optional user context

949:    Level: intermediate

951: .keywords: SNES, nonlinear, set, application, context

953: .seealso: SNESGetApplicationContext()
954: @*/
955: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
956: {
958:   KSP            ksp;

962:   SNESGetKSP(snes,&ksp);
963:   KSPSetApplicationContext(ksp,usrP);
964:   snes->user = usrP;
965:   return(0);
966: }

970: /*@
971:    SNESGetApplicationContext - Gets the user-defined context for the
972:    nonlinear solvers.

974:    Not Collective

976:    Input Parameter:
977: .  snes - SNES context

979:    Output Parameter:
980: .  usrP - user context

982:    Level: intermediate

984: .keywords: SNES, nonlinear, get, application, context

986: .seealso: SNESSetApplicationContext()
987: @*/
988: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
989: {
992:   *(void**)usrP = snes->user;
993:   return(0);
994: }

998: /*@
999:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1000:    at this time.

1002:    Not Collective

1004:    Input Parameter:
1005: .  snes - SNES context

1007:    Output Parameter:
1008: .  iter - iteration number

1010:    Notes:
1011:    For example, during the computation of iteration 2 this would return 1.

1013:    This is useful for using lagged Jacobians (where one does not recompute the
1014:    Jacobian at each SNES iteration). For example, the code
1015: .vb
1016:       SNESGetIterationNumber(snes,&it);
1017:       if (!(it % 2)) {
1018:         [compute Jacobian here]
1019:       }
1020: .ve
1021:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1022:    recomputed every second SNES iteration.

1024:    Level: intermediate

1026: .keywords: SNES, nonlinear, get, iteration, number,

1028: .seealso:   SNESGetFunctionNorm(), SNESGetLinearSolveIterations()
1029: @*/
1030: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1031: {
1035:   *iter = snes->iter;
1036:   return(0);
1037: }

1041: /*@
1042:    SNESSetIterationNumber - Sets the current iteration number.

1044:    Not Collective

1046:    Input Parameter:
1047: .  snes - SNES context
1048: .  iter - iteration number

1050:    Level: developer

1052: .keywords: SNES, nonlinear, set, iteration, number,

1054: .seealso:   SNESGetFunctionNorm(), SNESGetLinearSolveIterations()
1055: @*/
1056: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1057: {

1062:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1063:   snes->iter = iter;
1064:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1065:   return(0);
1066: }

1070: /*@
1071:    SNESGetFunctionNorm - Gets the norm of the current function that was set
1072:    with SNESSSetFunction().

1074:    Collective on SNES

1076:    Input Parameter:
1077: .  snes - SNES context

1079:    Output Parameter:
1080: .  fnorm - 2-norm of function

1082:    Level: intermediate

1084: .keywords: SNES, nonlinear, get, function, norm

1086: .seealso: SNESGetFunction(), SNESGetIterationNumber(), SNESGetLinearSolveIterations()
1087: @*/
1088: PetscErrorCode  SNESGetFunctionNorm(SNES snes,PetscReal *fnorm)
1089: {
1093:   *fnorm = snes->norm;
1094:   return(0);
1095: }


1100: /*@
1101:    SNESSetFunctionNorm - Sets the 2-norm of the current function computed using VecNorm().

1103:    Collective on SNES

1105:    Input Parameter:
1106: .  snes - SNES context
1107: .  fnorm - 2-norm of function

1109:    Level: developer

1111: .keywords: SNES, nonlinear, set, function, norm

1113: .seealso: SNESSetFunction(), SNESSetIterationNumber(), VecNorm().
1114: @*/
1115: PetscErrorCode  SNESSetFunctionNorm(SNES snes,PetscReal fnorm)
1116: {


1122:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1123:   snes->norm = fnorm;
1124:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1125:   return(0);
1126: }

1130: /*@
1131:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1132:    attempted by the nonlinear solver.

1134:    Not Collective

1136:    Input Parameter:
1137: .  snes - SNES context

1139:    Output Parameter:
1140: .  nfails - number of unsuccessful steps attempted

1142:    Notes:
1143:    This counter is reset to zero for each successive call to SNESSolve().

1145:    Level: intermediate

1147: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1149: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1150:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1151: @*/
1152: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1153: {
1157:   *nfails = snes->numFailures;
1158:   return(0);
1159: }

1163: /*@
1164:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1165:    attempted by the nonlinear solver before it gives up.

1167:    Not Collective

1169:    Input Parameters:
1170: +  snes     - SNES context
1171: -  maxFails - maximum of unsuccessful steps

1173:    Level: intermediate

1175: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1177: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1178:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1179: @*/
1180: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1181: {
1184:   snes->maxFailures = maxFails;
1185:   return(0);
1186: }

1190: /*@
1191:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1192:    attempted by the nonlinear solver before it gives up.

1194:    Not Collective

1196:    Input Parameter:
1197: .  snes     - SNES context

1199:    Output Parameter:
1200: .  maxFails - maximum of unsuccessful steps

1202:    Level: intermediate

1204: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1206: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1207:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1209: @*/
1210: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1211: {
1215:   *maxFails = snes->maxFailures;
1216:   return(0);
1217: }

1221: /*@
1222:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1223:      done by SNES.

1225:    Not Collective

1227:    Input Parameter:
1228: .  snes     - SNES context

1230:    Output Parameter:
1231: .  nfuncs - number of evaluations

1233:    Level: intermediate

1235:    Notes: Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1237: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1239: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1240: @*/
1241: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1242: {
1246:   *nfuncs = snes->nfuncs;
1247:   return(0);
1248: }

1252: /*@
1253:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1254:    linear solvers.

1256:    Not Collective

1258:    Input Parameter:
1259: .  snes - SNES context

1261:    Output Parameter:
1262: .  nfails - number of failed solves

1264:    Notes:
1265:    This counter is reset to zero for each successive call to SNESSolve().

1267:    Level: intermediate

1269: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1271: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1272: @*/
1273: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1274: {
1278:   *nfails = snes->numLinearSolveFailures;
1279:   return(0);
1280: }

1284: /*@
1285:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1286:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1288:    Logically Collective on SNES

1290:    Input Parameters:
1291: +  snes     - SNES context
1292: -  maxFails - maximum allowed linear solve failures

1294:    Level: intermediate

1296:    Notes: By default this is 0; that is SNES returns on the first failed linear solve

1298: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1300: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations()
1301: @*/
1302: PetscErrorCode  SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1303: {
1307:   snes->maxLinearSolveFailures = maxFails;
1308:   return(0);
1309: }

1313: /*@
1314:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1315:      are allowed before SNES terminates

1317:    Not Collective

1319:    Input Parameter:
1320: .  snes     - SNES context

1322:    Output Parameter:
1323: .  maxFails - maximum of unsuccessful solves allowed

1325:    Level: intermediate

1327:    Notes: By default this is 1; that is SNES returns on the first failed linear solve

1329: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1331: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1332: @*/
1333: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1334: {
1338:   *maxFails = snes->maxLinearSolveFailures;
1339:   return(0);
1340: }

1344: /*@
1345:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1346:    used by the nonlinear solver.

1348:    Not Collective

1350:    Input Parameter:
1351: .  snes - SNES context

1353:    Output Parameter:
1354: .  lits - number of linear iterations

1356:    Notes:
1357:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1359:    Level: intermediate

1361: .keywords: SNES, nonlinear, get, number, linear, iterations

1363: .seealso:  SNESGetIterationNumber(), SNESGetFunctionNorm(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1364: @*/
1365: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1366: {
1370:   *lits = snes->linear_its;
1371:   return(0);
1372: }

1376: /*@
1377:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1378:    are reset every time SNESSolve() is called.

1380:    Logically Collective on SNES

1382:    Input Parameter:
1383: +  snes - SNES context
1384: -  reset - whether to reset the counters or not

1386:    Notes:
1387:    This is automatically called with FALSE

1389:    Level: developer

1391: .keywords: SNES, nonlinear, set, reset, number, linear, iterations

1393: .seealso:  SNESGetNumberFunctionEvals(), SNESGetNumberLinearSolveIterations(), SNESGetPC()
1394: @*/
1395: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1396: {
1400:   snes->counters_reset = reset;
1401:   return(0);
1402: }


1407: /*@
1408:    SNESSetKSP - Sets a KSP context for the SNES object to use

1410:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1412:    Input Parameters:
1413: +  snes - the SNES context
1414: -  ksp - the KSP context

1416:    Notes:
1417:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1418:    so this routine is rarely needed.

1420:    The KSP object that is already in the SNES object has its reference count
1421:    decreased by one.

1423:    Level: developer

1425: .keywords: SNES, nonlinear, get, KSP, context

1427: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1428: @*/
1429: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1430: {

1437:   PetscObjectReference((PetscObject)ksp);
1438:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1439:   snes->ksp = ksp;
1440:   return(0);
1441: }

1443: /* -----------------------------------------------------------*/
1446: /*@
1447:    SNESCreate - Creates a nonlinear solver context.

1449:    Collective on MPI_Comm

1451:    Input Parameters:
1452: .  comm - MPI communicator

1454:    Output Parameter:
1455: .  outsnes - the new SNES context

1457:    Options Database Keys:
1458: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1459:                and no preconditioning matrix
1460: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1461:                products, and a user-provided preconditioning matrix
1462:                as set by SNESSetJacobian()
1463: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1465:    Level: beginner

1467: .keywords: SNES, nonlinear, create, context

1469: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner()

1471: @*/
1472: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1473: {
1475:   SNES           snes;
1476:   SNESKSPEW      *kctx;

1480:   *outsnes = NULL;
1481:   SNESInitializePackage();

1483:   PetscHeaderCreate(snes,_p_SNES,struct _SNESOps,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1485:   snes->ops->converged    = SNESConvergedDefault;
1486:   snes->usesksp           = PETSC_TRUE;
1487:   snes->tolerancesset     = PETSC_FALSE;
1488:   snes->max_its           = 50;
1489:   snes->max_funcs         = 10000;
1490:   snes->norm              = 0.0;
1491:   snes->normschedule      = SNES_NORM_ALWAYS;
1492:   snes->functype          = SNES_FUNCTION_DEFAULT;
1493: #if defined(PETSC_USE_REAL_SINGLE)
1494:   snes->rtol              = 1.e-5;
1495: #else
1496:   snes->rtol              = 1.e-8;
1497: #endif
1498:   snes->ttol              = 0.0;
1499: #if defined(PETSC_USE_REAL_SINGLE)
1500:   snes->abstol            = 1.e-25;
1501: #else
1502:   snes->abstol            = 1.e-50;
1503: #endif
1504:   snes->stol              = 1.e-8;
1505: #if defined(PETSC_USE_REAL_SINGLE)
1506:   snes->deltatol          = 1.e-6;
1507: #else
1508:   snes->deltatol          = 1.e-12;
1509: #endif
1510:   snes->nfuncs            = 0;
1511:   snes->numFailures       = 0;
1512:   snes->maxFailures       = 1;
1513:   snes->linear_its        = 0;
1514:   snes->lagjacobian       = 1;
1515:   snes->jac_iter          = 0;
1516:   snes->lagjac_persist    = PETSC_FALSE;
1517:   snes->lagpreconditioner = 1;
1518:   snes->pre_iter          = 0;
1519:   snes->lagpre_persist    = PETSC_FALSE;
1520:   snes->numbermonitors    = 0;
1521:   snes->data              = 0;
1522:   snes->setupcalled       = PETSC_FALSE;
1523:   snes->ksp_ewconv        = PETSC_FALSE;
1524:   snes->nwork             = 0;
1525:   snes->work              = 0;
1526:   snes->nvwork            = 0;
1527:   snes->vwork             = 0;
1528:   snes->conv_hist_len     = 0;
1529:   snes->conv_hist_max     = 0;
1530:   snes->conv_hist         = NULL;
1531:   snes->conv_hist_its     = NULL;
1532:   snes->conv_hist_reset   = PETSC_TRUE;
1533:   snes->counters_reset    = PETSC_TRUE;
1534:   snes->vec_func_init_set = PETSC_FALSE;
1535:   snes->reason            = SNES_CONVERGED_ITERATING;
1536:   snes->pcside            = PC_RIGHT;

1538:   snes->mf          = PETSC_FALSE;
1539:   snes->mf_operator = PETSC_FALSE;
1540:   snes->mf_version  = 1;

1542:   snes->numLinearSolveFailures = 0;
1543:   snes->maxLinearSolveFailures = 1;

1545:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1546:   PetscNewLog(snes,&kctx);

1548:   snes->kspconvctx  = (void*)kctx;
1549:   kctx->version     = 2;
1550:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1551:                              this was too large for some test cases */
1552:   kctx->rtol_last   = 0.0;
1553:   kctx->rtol_max    = .9;
1554:   kctx->gamma       = 1.0;
1555:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1556:   kctx->alpha2      = kctx->alpha;
1557:   kctx->threshold   = .1;
1558:   kctx->lresid_last = 0.0;
1559:   kctx->norm_last   = 0.0;

1561:   *outsnes = snes;
1562:   return(0);
1563: }

1565: /*MC
1566:     SNESFunction - functional form used to convey the nonlinear function to be solved by SNES

1568:      Synopsis:
1569:      #include <petscsnes.h>
1570:      SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1572:      Input Parameters:
1573: +     snes - the SNES context
1574: .     x    - state at which to evaluate residual
1575: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1577:      Output Parameter:
1578: .     f  - vector to put residual (function value)

1580:    Level: intermediate

1582: .seealso:   SNESSetFunction(), SNESGetFunction()
1583: M*/

1587: /*@C
1588:    SNESSetFunction - Sets the function evaluation routine and function
1589:    vector for use by the SNES routines in solving systems of nonlinear
1590:    equations.

1592:    Logically Collective on SNES

1594:    Input Parameters:
1595: +  snes - the SNES context
1596: .  r - vector to store function value
1597: .  f - function evaluation routine; see SNESFunction for calling sequence details
1598: -  ctx - [optional] user-defined context for private data for the
1599:          function evaluation routine (may be NULL)

1601:    Notes:
1602:    The Newton-like methods typically solve linear systems of the form
1603: $      f'(x) x = -f(x),
1604:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1606:    Level: beginner

1608: .keywords: SNES, nonlinear, set, function

1610: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1611: @*/
1612: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1613: {
1615:   DM             dm;

1619:   if (r) {
1622:     PetscObjectReference((PetscObject)r);
1623:     VecDestroy(&snes->vec_func);

1625:     snes->vec_func = r;
1626:   }
1627:   SNESGetDM(snes,&dm);
1628:   DMSNESSetFunction(dm,f,ctx);
1629:   return(0);
1630: }


1635: /*@C
1636:    SNESSetInitialFunction - Sets the function vector to be used as the
1637:    function norm at the initialization of the method.  In some
1638:    instances, the user has precomputed the function before calling
1639:    SNESSolve.  This function allows one to avoid a redundant call
1640:    to SNESComputeFunction in that case.

1642:    Logically Collective on SNES

1644:    Input Parameters:
1645: +  snes - the SNES context
1646: -  f - vector to store function value

1648:    Notes:
1649:    This should not be modified during the solution procedure.

1651:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1653:    Level: developer

1655: .keywords: SNES, nonlinear, set, function

1657: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1658: @*/
1659: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1660: {
1662:   Vec            vec_func;

1668:   if (snes->pcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1669:     snes->vec_func_init_set = PETSC_FALSE;
1670:     return(0);
1671:   }
1672:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1673:   VecCopy(f, vec_func);

1675:   snes->vec_func_init_set = PETSC_TRUE;
1676:   return(0);
1677: }

1681: /*@
1682:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1683:    of the SNES method.

1685:    Logically Collective on SNES

1687:    Input Parameters:
1688: +  snes - the SNES context
1689: -  normschedule - the frequency of norm computation

1691:    Notes:
1692:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1693:    of the nonlinear function and the taking of its norm at every iteration to
1694:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1695:    (SNESGS) and the like do not require the norm of the function to be computed, and therfore
1696:    may either be monitored for convergence or not.  As these are often used as nonlinear
1697:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1698:    their solution.

1700:    Level: developer

1702: .keywords: SNES, nonlinear, set, function, norm, type

1704: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1705: @*/
1706: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1707: {
1710:   snes->normschedule = normschedule;
1711:   return(0);
1712: }


1717: /*@
1718:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1719:    of the SNES method.

1721:    Logically Collective on SNES

1723:    Input Parameters:
1724: +  snes - the SNES context
1725: -  normschedule - the type of the norm used

1727:    Level: advanced

1729: .keywords: SNES, nonlinear, set, function, norm, type

1731: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1732: @*/
1733: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1734: {
1737:   *normschedule = snes->normschedule;
1738:   return(0);
1739: }


1744: /*@C
1745:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
1746:    of the SNES method.

1748:    Logically Collective on SNES

1750:    Input Parameters:
1751: +  snes - the SNES context
1752: -  normschedule - the frequency of norm computation

1754:    Notes:
1755:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1756:    of the nonlinear function and the taking of its norm at every iteration to
1757:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1758:    (SNESGS) and the like do not require the norm of the function to be computed, and therfore
1759:    may either be monitored for convergence or not.  As these are often used as nonlinear
1760:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1761:    their solution.

1763:    Level: developer

1765: .keywords: SNES, nonlinear, set, function, norm, type

1767: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1768: @*/
1769: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
1770: {
1773:   snes->functype = type;
1774:   return(0);
1775: }


1780: /*@C
1781:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
1782:    of the SNES method.

1784:    Logically Collective on SNES

1786:    Input Parameters:
1787: +  snes - the SNES context
1788: -  normschedule - the type of the norm used

1790:    Level: advanced

1792: .keywords: SNES, nonlinear, set, function, norm, type

1794: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1795: @*/
1796: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
1797: {
1800:   *type = snes->functype;
1801:   return(0);
1802: }

1804: /*MC
1805:     SNESGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

1807:      Synopsis:
1808:      #include <petscsnes.h>
1809: $    SNESGSFunction(SNES snes,Vec x,Vec b,void *ctx);

1811: +  X   - solution vector
1812: .  B   - RHS vector
1813: -  ctx - optional user-defined Gauss-Seidel context

1815:    Level: intermediate

1817: .seealso:   SNESSetGS(), SNESGetGS()
1818: M*/

1822: /*@C
1823:    SNESSetGS - Sets the user nonlinear Gauss-Seidel routine for
1824:    use with composed nonlinear solvers.

1826:    Input Parameters:
1827: +  snes   - the SNES context
1828: .  SNESGSFunction - function evaluation routine
1829: -  ctx    - [optional] user-defined context for private data for the
1830:             smoother evaluation routine (may be NULL)

1832:    Notes:
1833:    The GS routines are used by the composed nonlinear solver to generate
1834:     a problem appropriate update to the solution, particularly FAS.

1836:    Level: intermediate

1838: .keywords: SNES, nonlinear, set, Gauss-Seidel

1840: .seealso: SNESGetFunction(), SNESComputeGS()
1841: @*/
1842: PetscErrorCode SNESSetGS(SNES snes,PetscErrorCode (*SNESGSFunction)(SNES,Vec,Vec,void*),void *ctx)
1843: {
1845:   DM             dm;

1849:   SNESGetDM(snes,&dm);
1850:   DMSNESSetGS(dm,SNESGSFunction,ctx);
1851:   return(0);
1852: }

1856: PETSC_EXTERN PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
1857: {
1859:   DM             dm;
1860:   DMSNES         sdm;

1863:   SNESGetDM(snes,&dm);
1864:   DMGetDMSNES(dm,&sdm);
1865:   /*  A(x)*x - b(x) */
1866:   if (sdm->ops->computepfunction) {
1867:     (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
1868:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");

1870:   if (sdm->ops->computepjacobian) {
1871:     (*sdm->ops->computepjacobian)(snes,x,&snes->jacobian,&snes->jacobian_pre,&snes->matstruct,sdm->pctx);
1872:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard matrix.");
1873:   VecScale(f,-1.0);
1874:   MatMultAdd(snes->jacobian,x,f,f);
1875:   return(0);
1876: }

1880: PETSC_EXTERN PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat *J,Mat *B,MatStructure *flag,void *ctx)
1881: {
1883:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
1884:   *flag = snes->matstruct;
1885:   return(0);
1886: }

1890: /*@C
1891:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

1893:    Logically Collective on SNES

1895:    Input Parameters:
1896: +  snes - the SNES context
1897: .  r - vector to store function value
1898: .  b - function evaluation routine
1899: .  Amat - matrix with which A(x) x - b(x) is to be computed
1900: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
1901: .  J  - function to compute matrix value
1902: -  ctx - [optional] user-defined context for private data for the
1903:          function evaluation routine (may be NULL)

1905:    Notes:
1906:     We do not recomemend using this routine. It is far better to provide the nonlinear function F() and some approximation to the Jacobian and use
1907:     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.

1909:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

1911: $     Solves the equation A(x) x = b(x) via the defect correction algorithm A(x^{n}) (x^{n+1} - x^{n}) = b(x^{n}) - A(x^{n})x^{n}
1912: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

1914:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

1916:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
1917:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

1919:    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
1920:    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
1921:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

1923:    Level: intermediate

1925: .keywords: SNES, nonlinear, set, function

1927: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard()
1928: @*/
1929: PetscErrorCode  SNESSetPicard(SNES snes,Vec r,PetscErrorCode (*b)(SNES,Vec,Vec,void*),Mat Amat, Mat Pmat, PetscErrorCode (*J)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void *ctx)
1930: {
1932:   DM             dm;

1936:   SNESGetDM(snes, &dm);
1937:   DMSNESSetPicard(dm,b,J,ctx);
1938:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
1939:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
1940:   return(0);
1941: }

1945: /*@C
1946:    SNESGetPicard - Returns the context for the Picard iteration

1948:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

1950:    Input Parameter:
1951: .  snes - the SNES context

1953:    Output Parameter:
1954: +  r - the function (or NULL)
1955: .  f - the function (or NULL); see SNESFunction for calling sequence details
1956: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
1957: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
1958: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
1959: -  ctx - the function context (or NULL)

1961:    Level: advanced

1963: .keywords: SNES, nonlinear, get, function

1965: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
1966: @*/
1967: PetscErrorCode  SNESGetPicard(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),Mat *Amat, Mat *Pmat, PetscErrorCode (**J)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void **ctx)
1968: {
1970:   DM             dm;

1974:   SNESGetFunction(snes,r,NULL,NULL);
1975:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
1976:   SNESGetDM(snes,&dm);
1977:   DMSNESGetPicard(dm,f,J,ctx);
1978:   return(0);
1979: }

1983: /*@C
1984:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

1986:    Logically Collective on SNES

1988:    Input Parameters:
1989: +  snes - the SNES context
1990: .  func - function evaluation routine
1991: -  ctx - [optional] user-defined context for private data for the
1992:          function evaluation routine (may be NULL)

1994:    Calling sequence of func:
1995: $    func (SNES snes,Vec x,void *ctx);

1997: .  f - function vector
1998: -  ctx - optional user-defined function context

2000:    Level: intermediate

2002: .keywords: SNES, nonlinear, set, function

2004: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
2005: @*/
2006: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
2007: {
2010:   if (func) snes->ops->computeinitialguess = func;
2011:   if (ctx)  snes->initialguessP            = ctx;
2012:   return(0);
2013: }

2015: /* --------------------------------------------------------------- */
2018: /*@C
2019:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
2020:    it assumes a zero right hand side.

2022:    Logically Collective on SNES

2024:    Input Parameter:
2025: .  snes - the SNES context

2027:    Output Parameter:
2028: .  rhs - the right hand side vector or NULL if the right hand side vector is null

2030:    Level: intermediate

2032: .keywords: SNES, nonlinear, get, function, right hand side

2034: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2035: @*/
2036: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2037: {
2041:   *rhs = snes->vec_rhs;
2042:   return(0);
2043: }

2047: /*@
2048:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2050:    Collective on SNES

2052:    Input Parameters:
2053: +  snes - the SNES context
2054: -  x - input vector

2056:    Output Parameter:
2057: .  y - function vector, as set by SNESSetFunction()

2059:    Notes:
2060:    SNESComputeFunction() is typically used within nonlinear solvers
2061:    implementations, so most users would not generally call this routine
2062:    themselves.

2064:    Level: developer

2066: .keywords: SNES, nonlinear, compute, function

2068: .seealso: SNESSetFunction(), SNESGetFunction()
2069: @*/
2070: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2071: {
2073:   DM             dm;
2074:   DMSNES         sdm;

2082:   VecValidValues(x,2,PETSC_TRUE);

2084:   SNESGetDM(snes,&dm);
2085:   DMGetDMSNES(dm,&sdm);
2086:   if (sdm->ops->computefunction) {
2087:     PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2088:     PetscStackPush("SNES user function");
2089:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2090:     PetscStackPop;
2091:     PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2092:   } else if (snes->vec_rhs) {
2093:     MatMult(snes->jacobian, x, y);
2094:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2095:   if (snes->vec_rhs) {
2096:     VecAXPY(y,-1.0,snes->vec_rhs);
2097:   }
2098:   snes->nfuncs++;
2099:   VecValidValues(y,3,PETSC_FALSE);
2100:   return(0);
2101: }

2105: /*@
2106:    SNESComputeGS - Calls the Gauss-Seidel function that has been set with  SNESSetGS().

2108:    Collective on SNES

2110:    Input Parameters:
2111: +  snes - the SNES context
2112: .  x - input vector
2113: -  b - rhs vector

2115:    Output Parameter:
2116: .  x - new solution vector

2118:    Notes:
2119:    SNESComputeGS() is typically used within composed nonlinear solver
2120:    implementations, so most users would not generally call this routine
2121:    themselves.

2123:    Level: developer

2125: .keywords: SNES, nonlinear, compute, function

2127: .seealso: SNESSetGS(), SNESComputeFunction()
2128: @*/
2129: PetscErrorCode  SNESComputeGS(SNES snes,Vec b,Vec x)
2130: {
2132:   DM             dm;
2133:   DMSNES         sdm;

2141:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2142:   PetscLogEventBegin(SNES_GSEval,snes,x,b,0);
2143:   SNESGetDM(snes,&dm);
2144:   DMGetDMSNES(dm,&sdm);
2145:   if (sdm->ops->computegs) {
2146:     PetscStackPush("SNES user GS");
2147:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2148:     PetscStackPop;
2149:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetGS() before SNESComputeGS(), likely called from SNESSolve().");
2150:   PetscLogEventEnd(SNES_GSEval,snes,x,b,0);
2151:   VecValidValues(x,3,PETSC_FALSE);
2152:   return(0);
2153: }

2157: /*@
2158:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2160:    Collective on SNES and Mat

2162:    Input Parameters:
2163: +  snes - the SNES context
2164: -  x - input vector

2166:    Output Parameters:
2167: +  A - Jacobian matrix
2168: .  B - optional preconditioning matrix
2169: -  flag - flag indicating matrix structure (one of, SAME_NONZERO_PATTERN,DIFFERENT_NONZERO_PATTERN,SAME_PRECONDITIONER)

2171:   Options Database Keys:
2172: +    -snes_lag_preconditioner <lag>
2173: .    -snes_lag_jacobian <lag>
2174: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2175: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2176: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2177: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2178: .    -snes_compare_coloring - Compute the finite differece Jacobian using coloring and display norms of difference
2179: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2180: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2181: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2182: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2183: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2184: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2187:    Notes:
2188:    Most users should not need to explicitly call this routine, as it
2189:    is used internally within the nonlinear solvers.

2191:    See KSPSetOperators() for important information about setting the
2192:    flag parameter.

2194:    Level: developer

2196: .keywords: SNES, compute, Jacobian, matrix

2198: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2199: @*/
2200: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat *A,Mat *B,MatStructure *flg)
2201: {
2203:   PetscBool      flag;
2204:   DM             dm;
2205:   DMSNES         sdm;

2212:   VecValidValues(X,2,PETSC_TRUE);
2213:   SNESGetDM(snes,&dm);
2214:   DMGetDMSNES(dm,&sdm);

2216:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2218:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2220:   if (snes->lagjacobian == -2) {
2221:     snes->lagjacobian = -1;

2223:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2224:   } else if (snes->lagjacobian == -1) {
2225:     *flg = SAME_PRECONDITIONER;
2226:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2227:     PetscObjectTypeCompare((PetscObject)*A,MATMFFD,&flag);
2228:     if (flag) {
2229:       MatAssemblyBegin(*A,MAT_FINAL_ASSEMBLY);
2230:       MatAssemblyEnd(*A,MAT_FINAL_ASSEMBLY);
2231:     }
2232:     return(0);
2233:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2234:     *flg = SAME_PRECONDITIONER;
2235:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2236:     PetscObjectTypeCompare((PetscObject)*A,MATMFFD,&flag);
2237:     if (flag) {
2238:       MatAssemblyBegin(*A,MAT_FINAL_ASSEMBLY);
2239:       MatAssemblyEnd(*A,MAT_FINAL_ASSEMBLY);
2240:     }
2241:     return(0);
2242:   }
2243:   if (snes->pc && snes->pcside == PC_LEFT) {
2244:       MatAssemblyBegin(*A,MAT_FINAL_ASSEMBLY);
2245:       MatAssemblyEnd(*A,MAT_FINAL_ASSEMBLY);
2246:       return(0);
2247:   }

2249:   *flg = DIFFERENT_NONZERO_PATTERN;
2250:   PetscLogEventBegin(SNES_JacobianEval,snes,X,*A,*B);

2252:   PetscStackPush("SNES user Jacobian function");
2253:   (*sdm->ops->computejacobian)(snes,X,A,B,flg,sdm->jacobianctx);
2254:   PetscStackPop;

2256:   PetscLogEventEnd(SNES_JacobianEval,snes,X,*A,*B);

2258:   if (snes->lagpreconditioner == -2) {
2259:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");

2261:     snes->lagpreconditioner = -1;
2262:   } else if (snes->lagpreconditioner == -1) {
2263:     *flg = SAME_PRECONDITIONER;
2264:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2265:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2266:     *flg = SAME_PRECONDITIONER;
2267:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2268:   }

2270:   /* make sure user returned a correct Jacobian and preconditioner */
2273:   {
2274:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2275:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_explicit",&flag,NULL);
2276:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",&flag_draw,NULL);
2277:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",&flag_contour,NULL);
2278:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_operator",&flag_operator,NULL);
2279:     if (flag || flag_draw || flag_contour) {
2280:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2281:       MatStructure mstruct;
2282:       PetscViewer  vdraw,vstdout;
2283:       PetscBool    flg;
2284:       if (flag_operator) {
2285:         MatComputeExplicitOperator(*A,&Bexp_mine);
2286:         Bexp = Bexp_mine;
2287:       } else {
2288:         /* See if the preconditioning matrix can be viewed and added directly */
2289:         PetscObjectTypeCompareAny((PetscObject)*B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2290:         if (flg) Bexp = *B;
2291:         else {
2292:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2293:           MatComputeExplicitOperator(*B,&Bexp_mine);
2294:           Bexp = Bexp_mine;
2295:         }
2296:       }
2297:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2298:       SNESComputeJacobianDefault(snes,X,&FDexp,&FDexp,&mstruct,NULL);
2299:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2300:       if (flag_draw || flag_contour) {
2301:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2302:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2303:       } else vdraw = NULL;
2304:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2305:       if (flag) {MatView(Bexp,vstdout);}
2306:       if (vdraw) {MatView(Bexp,vdraw);}
2307:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2308:       if (flag) {MatView(FDexp,vstdout);}
2309:       if (vdraw) {MatView(FDexp,vdraw);}
2310:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2311:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2312:       if (flag) {MatView(FDexp,vstdout);}
2313:       if (vdraw) {              /* Always use contour for the difference */
2314:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2315:         MatView(FDexp,vdraw);
2316:         PetscViewerPopFormat(vdraw);
2317:       }
2318:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2319:       PetscViewerDestroy(&vdraw);
2320:       MatDestroy(&Bexp_mine);
2321:       MatDestroy(&FDexp);
2322:     }
2323:   }
2324:   {
2325:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2326:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2327:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring",&flag,NULL);
2328:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_display",&flag_display,NULL);
2329:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",&flag_draw,NULL);
2330:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",&flag_contour,NULL);
2331:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",&flag_threshold,NULL);
2332:     PetscOptionsGetReal(((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2333:     PetscOptionsGetReal(((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2334:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2335:       Mat            Bfd;
2336:       MatStructure   mstruct;
2337:       PetscViewer    vdraw,vstdout;
2338:       MatColoring    coloring;
2339:       ISColoring     iscoloring;
2340:       MatFDColoring  matfdcoloring;
2341:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2342:       void           *funcctx;
2343:       PetscReal      norm1,norm2,normmax;

2345:       MatDuplicate(*B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2346:       MatColoringCreate(Bfd,&coloring);
2347:       MatColoringSetType(coloring,MATCOLORINGSL);
2348:       MatColoringSetFromOptions(coloring);
2349:       MatColoringApply(coloring,&iscoloring);
2350:       MatColoringDestroy(&coloring);
2351:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2352:       MatFDColoringSetFromOptions(matfdcoloring);
2353:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2354:       ISColoringDestroy(&iscoloring);

2356:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2357:       SNESGetFunction(snes,NULL,&func,&funcctx);
2358:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2359:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2360:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2361:       MatFDColoringSetFromOptions(matfdcoloring);
2362:       MatFDColoringApply(Bfd,matfdcoloring,X,&mstruct,snes);
2363:       MatFDColoringDestroy(&matfdcoloring);

2365:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2366:       if (flag_draw || flag_contour) {
2367:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2368:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2369:       } else vdraw = NULL;
2370:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2371:       if (flag_display) {MatView(*B,vstdout);}
2372:       if (vdraw) {MatView(*B,vdraw);}
2373:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2374:       if (flag_display) {MatView(Bfd,vstdout);}
2375:       if (vdraw) {MatView(Bfd,vdraw);}
2376:       MatAYPX(Bfd,-1.0,*B,SAME_NONZERO_PATTERN);
2377:       MatNorm(Bfd,NORM_1,&norm1);
2378:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2379:       MatNorm(Bfd,NORM_MAX,&normmax);
2380:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2381:       if (flag_display) {MatView(Bfd,vstdout);}
2382:       if (vdraw) {              /* Always use contour for the difference */
2383:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2384:         MatView(Bfd,vdraw);
2385:         PetscViewerPopFormat(vdraw);
2386:       }
2387:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2389:       if (flag_threshold) {
2390:         PetscInt bs,rstart,rend,i;
2391:         MatGetBlockSize(*B,&bs);
2392:         MatGetOwnershipRange(*B,&rstart,&rend);
2393:         for (i=rstart; i<rend; i++) {
2394:           const PetscScalar *ba,*ca;
2395:           const PetscInt    *bj,*cj;
2396:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2397:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2398:           MatGetRow(*B,i,&bn,&bj,&ba);
2399:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2400:           if (bn != cn) SETERRQ(((PetscObject)*A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2401:           for (j=0; j<bn; j++) {
2402:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2403:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2404:               maxentrycol = bj[j];
2405:               maxentry    = PetscRealPart(ba[j]);
2406:             }
2407:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2408:               maxdiffcol = bj[j];
2409:               maxdiff    = PetscRealPart(ca[j]);
2410:             }
2411:             if (rdiff > maxrdiff) {
2412:               maxrdiffcol = bj[j];
2413:               maxrdiff    = rdiff;
2414:             }
2415:           }
2416:           if (maxrdiff > 1) {
2417:             PetscViewerASCIIPrintf(vstdout,"row %D (maxentry=%g at %D, maxdiff=%g at %D, maxrdiff=%g at %D):",i,(double)maxentry,maxentrycol,(double)maxdiff,maxdiffcol,(double)maxrdiff,maxrdiffcol);
2418:             for (j=0; j<bn; j++) {
2419:               PetscReal rdiff;
2420:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2421:               if (rdiff > 1) {
2422:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2423:               }
2424:             }
2425:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2426:           }
2427:           MatRestoreRow(*B,i,&bn,&bj,&ba);
2428:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2429:         }
2430:       }
2431:       PetscViewerDestroy(&vdraw);
2432:       MatDestroy(&Bfd);
2433:     }
2434:   }
2435:   return(0);
2436: }

2438: /*MC
2439:     SNESJacobianFunction - function used to convey the nonlinear Jacobian of the function to be solved by SNES

2441:      Synopsis:
2442:      #include <petscsnes.h>
2443: $     SNESJacobianFunction(SNES snes,Vec x,Mat *Amat,Mat *Pmat,int *flag,void *ctx);

2445: +  x - input vector
2446: .  Amat - the matrix that defines the (approximate) Jacobian
2447: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2448: .  flag - flag indicating information about the preconditioner matrix
2449:    structure (same as flag in KSPSetOperators()), one of SAME_NONZERO_PATTERN,DIFFERENT_NONZERO_PATTERN,SAME_PRECONDITIONER
2450: -  ctx - [optional] user-defined Jacobian context

2452:    Level: intermediate

2454: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2455: M*/

2459: /*@C
2460:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2461:    location to store the matrix.

2463:    Logically Collective on SNES and Mat

2465:    Input Parameters:
2466: +  snes - the SNES context
2467: .  Amat - the matrix that defines the (approximate) Jacobian
2468: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2469: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value)
2470: -  ctx - [optional] user-defined context for private data for the
2471:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2473:    Notes:
2474:    See KSPSetOperators() for important information about setting the flag
2475:    output parameter in the routine func().  Be sure to read this information!

2477:    The routine func() takes Mat * as the matrix arguments rather than Mat.
2478:    This allows the Jacobian evaluation routine to replace A and/or B with a
2479:    completely new new matrix structure (not just different matrix elements)
2480:    when appropriate, for instance, if the nonzero structure is changing
2481:    throughout the global iterations.

2483:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2484:    each matrix.

2486:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2487:    must be a MatFDColoring.

2489:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2490:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2492:    Level: beginner

2494: .keywords: SNES, nonlinear, set, Jacobian, matrix

2496: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J, SNESSetPicard()
2497: @*/
2498: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void *ctx)
2499: {
2501:   DM             dm;

2509:   SNESGetDM(snes,&dm);
2510:   DMSNESSetJacobian(dm,J,ctx);
2511:   if (Amat) {
2512:     PetscObjectReference((PetscObject)Amat);
2513:     MatDestroy(&snes->jacobian);

2515:     snes->jacobian = Amat;
2516:   }
2517:   if (Pmat) {
2518:     PetscObjectReference((PetscObject)Pmat);
2519:     MatDestroy(&snes->jacobian_pre);

2521:     snes->jacobian_pre = Pmat;
2522:   }
2523:   return(0);
2524: }

2528: /*@C
2529:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2530:    provided context for evaluating the Jacobian.

2532:    Not Collective, but Mat object will be parallel if SNES object is

2534:    Input Parameter:
2535: .  snes - the nonlinear solver context

2537:    Output Parameters:
2538: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
2539: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
2540: .  J - location to put Jacobian function (or NULL)
2541: -  ctx - location to stash Jacobian ctx (or NULL)

2543:    Level: advanced

2545: .seealso: SNESSetJacobian(), SNESComputeJacobian()
2546: @*/
2547: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void **ctx)
2548: {
2550:   DM             dm;
2551:   DMSNES         sdm;

2555:   if (Amat) *Amat = snes->jacobian;
2556:   if (Pmat) *Pmat = snes->jacobian_pre;
2557:   SNESGetDM(snes,&dm);
2558:   DMGetDMSNES(dm,&sdm);
2559:   if (J) *J = sdm->ops->computejacobian;
2560:   if (ctx) *ctx = sdm->jacobianctx;
2561:   return(0);
2562: }

2566: /*@
2567:    SNESSetUp - Sets up the internal data structures for the later use
2568:    of a nonlinear solver.

2570:    Collective on SNES

2572:    Input Parameters:
2573: .  snes - the SNES context

2575:    Notes:
2576:    For basic use of the SNES solvers the user need not explicitly call
2577:    SNESSetUp(), since these actions will automatically occur during
2578:    the call to SNESSolve().  However, if one wishes to control this
2579:    phase separately, SNESSetUp() should be called after SNESCreate()
2580:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

2582:    Level: advanced

2584: .keywords: SNES, nonlinear, setup

2586: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
2587: @*/
2588: PetscErrorCode  SNESSetUp(SNES snes)
2589: {
2591:   DM             dm;
2592:   DMSNES         sdm;
2593:   SNESLineSearch linesearch, pclinesearch;
2594:   void           *lsprectx,*lspostctx;
2595:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
2596:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
2597:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2598:   Vec            f,fpc;
2599:   void           *funcctx;
2600:   PetscErrorCode (*jac)(SNES,Vec,Mat*,Mat*,MatStructure*,void*);
2601:   void           *jacctx,*appctx;

2605:   if (snes->setupcalled) return(0);

2607:   if (!((PetscObject)snes)->type_name) {
2608:     SNESSetType(snes,SNESNEWTONLS);
2609:   }

2611:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

2613:   SNESGetDM(snes,&dm);
2614:   DMGetDMSNES(dm,&sdm);
2615:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
2616:   if (!sdm->ops->computejacobian) {
2617:     DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
2618:   }
2619:   if (!snes->vec_func) {
2620:     DMCreateGlobalVector(dm,&snes->vec_func);
2621:   }

2623:   if (!snes->ksp) {
2624:     SNESGetKSP(snes, &snes->ksp);
2625:   }

2627:   if (!snes->linesearch) {
2628:     SNESGetLineSearch(snes, &snes->linesearch);
2629:   }
2630:   SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);

2632:   if (snes->pc && (snes->pcside == PC_LEFT)) {
2633:     snes->mf          = PETSC_TRUE;
2634:     snes->mf_operator = PETSC_FALSE;
2635:   }

2637:   if (snes->mf) {
2638:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
2639:   }

2641:   if (snes->ops->usercompute && !snes->user) {
2642:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
2643:   }

2645:   if (snes->pc) {
2646:     /* copy the DM over */
2647:     SNESGetDM(snes,&dm);
2648:     SNESSetDM(snes->pc,dm);

2650:     SNESGetFunction(snes,&f,&func,&funcctx);
2651:     VecDuplicate(f,&fpc);
2652:     SNESSetFunction(snes->pc,fpc,func,funcctx);
2653:     SNESGetJacobian(snes,NULL,NULL,&jac,&jacctx);
2654:     SNESSetJacobian(snes->pc,NULL,NULL,jac,jacctx);
2655:     SNESGetApplicationContext(snes,&appctx);
2656:     SNESSetApplicationContext(snes->pc,appctx);
2657:     VecDestroy(&fpc);

2659:     /* copy the function pointers over */
2660:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->pc);

2662:     /* default to 1 iteration */
2663:     SNESSetTolerances(snes->pc,0.0,0.0,0.0,1,snes->pc->max_funcs);
2664:     if (snes->pcside==PC_RIGHT) {
2665:       SNESSetNormSchedule(snes->pc,SNES_NORM_FINAL_ONLY);
2666:     } else {
2667:       SNESSetNormSchedule(snes->pc,SNES_NORM_NONE);
2668:     }
2669:     SNESSetFromOptions(snes->pc);

2671:     /* copy the line search context over */
2672:     SNESGetLineSearch(snes,&linesearch);
2673:     SNESGetLineSearch(snes->pc,&pclinesearch);
2674:     SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
2675:     SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
2676:     SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
2677:     SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
2678:     PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
2679:   }

2681:   snes->jac_iter = 0;
2682:   snes->pre_iter = 0;

2684:   if (snes->ops->setup) {
2685:     (*snes->ops->setup)(snes);
2686:   }

2688:   if (snes->pc && (snes->pcside == PC_LEFT)) {
2689:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
2690:       SNESGetLineSearch(snes,&linesearch);
2691:       SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultPC);
2692:     }
2693:   }

2695:   snes->setupcalled = PETSC_TRUE;
2696:   return(0);
2697: }

2701: /*@
2702:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

2704:    Collective on SNES

2706:    Input Parameter:
2707: .  snes - iterative context obtained from SNESCreate()

2709:    Level: intermediate

2711:    Notes: Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

2713: .keywords: SNES, destroy

2715: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
2716: @*/
2717: PetscErrorCode  SNESReset(SNES snes)
2718: {

2723:   if (snes->ops->userdestroy && snes->user) {
2724:     (*snes->ops->userdestroy)((void**)&snes->user);
2725:     snes->user = NULL;
2726:   }
2727:   if (snes->pc) {
2728:     SNESReset(snes->pc);
2729:   }

2731:   if (snes->ops->reset) {
2732:     (*snes->ops->reset)(snes);
2733:   }
2734:   if (snes->ksp) {
2735:     KSPReset(snes->ksp);
2736:   }

2738:   if (snes->linesearch) {
2739:     SNESLineSearchReset(snes->linesearch);
2740:   }

2742:   VecDestroy(&snes->vec_rhs);
2743:   VecDestroy(&snes->vec_sol);
2744:   VecDestroy(&snes->vec_sol_update);
2745:   VecDestroy(&snes->vec_func);
2746:   MatDestroy(&snes->jacobian);
2747:   MatDestroy(&snes->jacobian_pre);
2748:   VecDestroyVecs(snes->nwork,&snes->work);
2749:   VecDestroyVecs(snes->nvwork,&snes->vwork);

2751:   snes->nwork       = snes->nvwork = 0;
2752:   snes->setupcalled = PETSC_FALSE;
2753:   return(0);
2754: }

2758: /*@
2759:    SNESDestroy - Destroys the nonlinear solver context that was created
2760:    with SNESCreate().

2762:    Collective on SNES

2764:    Input Parameter:
2765: .  snes - the SNES context

2767:    Level: beginner

2769: .keywords: SNES, nonlinear, destroy

2771: .seealso: SNESCreate(), SNESSolve()
2772: @*/
2773: PetscErrorCode  SNESDestroy(SNES *snes)
2774: {

2778:   if (!*snes) return(0);
2780:   if (--((PetscObject)(*snes))->refct > 0) {*snes = 0; return(0);}

2782:   SNESReset((*snes));
2783:   SNESDestroy(&(*snes)->pc);

2785:   /* if memory was published with SAWs then destroy it */
2786:   PetscObjectSAWsViewOff((PetscObject)*snes);
2787:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

2789:   DMDestroy(&(*snes)->dm);
2790:   KSPDestroy(&(*snes)->ksp);
2791:   SNESLineSearchDestroy(&(*snes)->linesearch);

2793:   PetscFree((*snes)->kspconvctx);
2794:   if ((*snes)->ops->convergeddestroy) {
2795:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
2796:   }
2797:   if ((*snes)->conv_malloc) {
2798:     PetscFree((*snes)->conv_hist);
2799:     PetscFree((*snes)->conv_hist_its);
2800:   }
2801:   SNESMonitorCancel((*snes));
2802:   PetscHeaderDestroy(snes);
2803:   return(0);
2804: }

2806: /* ----------- Routines to set solver parameters ---------- */

2810: /*@
2811:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

2813:    Logically Collective on SNES

2815:    Input Parameters:
2816: +  snes - the SNES context
2817: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2818:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

2820:    Options Database Keys:
2821: .    -snes_lag_preconditioner <lag>

2823:    Notes:
2824:    The default is 1
2825:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
2826:    If  -1 is used before the very first nonlinear solve the preconditioner is still built because there is no previous preconditioner to use

2828:    Level: intermediate

2830: .keywords: SNES, nonlinear, set, convergence, tolerances

2832: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian()

2834: @*/
2835: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
2836: {
2839:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
2840:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
2842:   snes->lagpreconditioner = lag;
2843:   return(0);
2844: }

2848: /*@
2849:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

2851:    Logically Collective on SNES

2853:    Input Parameters:
2854: +  snes - the SNES context
2855: -  steps - the number of refinements to do, defaults to 0

2857:    Options Database Keys:
2858: .    -snes_grid_sequence <steps>

2860:    Level: intermediate

2862:    Notes:
2863:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

2865: .keywords: SNES, nonlinear, set, convergence, tolerances

2867: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian()

2869: @*/
2870: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
2871: {
2875:   snes->gridsequence = steps;
2876:   return(0);
2877: }

2881: /*@
2882:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

2884:    Not Collective

2886:    Input Parameter:
2887: .  snes - the SNES context

2889:    Output Parameter:
2890: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2891:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

2893:    Options Database Keys:
2894: .    -snes_lag_preconditioner <lag>

2896:    Notes:
2897:    The default is 1
2898:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

2900:    Level: intermediate

2902: .keywords: SNES, nonlinear, set, convergence, tolerances

2904: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner()

2906: @*/
2907: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
2908: {
2911:   *lag = snes->lagpreconditioner;
2912:   return(0);
2913: }

2917: /*@
2918:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
2919:      often the preconditioner is rebuilt.

2921:    Logically Collective on SNES

2923:    Input Parameters:
2924: +  snes - the SNES context
2925: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2926:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

2928:    Options Database Keys:
2929: .    -snes_lag_jacobian <lag>

2931:    Notes:
2932:    The default is 1
2933:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
2934:    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
2935:    at the next Newton step but never again (unless it is reset to another value)

2937:    Level: intermediate

2939: .keywords: SNES, nonlinear, set, convergence, tolerances

2941: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobian()

2943: @*/
2944: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
2945: {
2948:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
2949:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
2951:   snes->lagjacobian = lag;
2952:   return(0);
2953: }

2957: /*@
2958:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

2960:    Not Collective

2962:    Input Parameter:
2963: .  snes - the SNES context

2965:    Output Parameter:
2966: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2967:          the Jacobian is built etc.

2969:    Options Database Keys:
2970: .    -snes_lag_jacobian <lag>

2972:    Notes:
2973:    The default is 1
2974:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

2976:    Level: intermediate

2978: .keywords: SNES, nonlinear, set, convergence, tolerances

2980: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner()

2982: @*/
2983: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
2984: {
2987:   *lag = snes->lagjacobian;
2988:   return(0);
2989: }

2993: /*@
2994:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

2996:    Logically collective on SNES

2998:    Input Parameter:
2999: +  snes - the SNES context
3000: -   flg - jacobian lagging persists if true

3002:    Options Database Keys:
3003: .    -snes_lag_jacobian_persists <flg>

3005:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3006:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3007:    timesteps may present huge efficiency gains.

3009:    Level: developer

3011: .keywords: SNES, nonlinear, lag, NPC

3013: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetPC()

3015: @*/
3016: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3017: {
3021:   snes->lagjac_persist = flg;
3022:   return(0);
3023: }

3027: /*@
3028:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple solves

3030:    Logically Collective on SNES

3032:    Input Parameter:
3033: +  snes - the SNES context
3034: -   flg - preconditioner lagging persists if true

3036:    Options Database Keys:
3037: .    -snes_lag_jacobian_persists <flg>

3039:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3040:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3041:    several timesteps may present huge efficiency gains.

3043:    Level: developer

3045: .keywords: SNES, nonlinear, lag, NPC

3047: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetPC()

3049: @*/
3050: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3051: {
3055:   snes->lagpre_persist = flg;
3056:   return(0);
3057: }

3061: /*@
3062:    SNESSetTolerances - Sets various parameters used in convergence tests.

3064:    Logically Collective on SNES

3066:    Input Parameters:
3067: +  snes - the SNES context
3068: .  abstol - absolute convergence tolerance
3069: .  rtol - relative convergence tolerance
3070: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3071: .  maxit - maximum number of iterations
3072: -  maxf - maximum number of function evaluations

3074:    Options Database Keys:
3075: +    -snes_atol <abstol> - Sets abstol
3076: .    -snes_rtol <rtol> - Sets rtol
3077: .    -snes_stol <stol> - Sets stol
3078: .    -snes_max_it <maxit> - Sets maxit
3079: -    -snes_max_funcs <maxf> - Sets maxf

3081:    Notes:
3082:    The default maximum number of iterations is 50.
3083:    The default maximum number of function evaluations is 1000.

3085:    Level: intermediate

3087: .keywords: SNES, nonlinear, set, convergence, tolerances

3089: .seealso: SNESSetTrustRegionTolerance()
3090: @*/
3091: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3092: {

3101:   if (abstol != PETSC_DEFAULT) {
3102:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3103:     snes->abstol = abstol;
3104:   }
3105:   if (rtol != PETSC_DEFAULT) {
3106:     if (rtol < 0.0 || 1.0 <= rtol) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Relative tolerance %g must be non-negative and less than 1.0",(double)rtol);
3107:     snes->rtol = rtol;
3108:   }
3109:   if (stol != PETSC_DEFAULT) {
3110:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3111:     snes->stol = stol;
3112:   }
3113:   if (maxit != PETSC_DEFAULT) {
3114:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3115:     snes->max_its = maxit;
3116:   }
3117:   if (maxf != PETSC_DEFAULT) {
3118:     if (maxf < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be non-negative",maxf);
3119:     snes->max_funcs = maxf;
3120:   }
3121:   snes->tolerancesset = PETSC_TRUE;
3122:   return(0);
3123: }

3127: /*@
3128:    SNESGetTolerances - Gets various parameters used in convergence tests.

3130:    Not Collective

3132:    Input Parameters:
3133: +  snes - the SNES context
3134: .  atol - absolute convergence tolerance
3135: .  rtol - relative convergence tolerance
3136: .  stol -  convergence tolerance in terms of the norm
3137:            of the change in the solution between steps
3138: .  maxit - maximum number of iterations
3139: -  maxf - maximum number of function evaluations

3141:    Notes:
3142:    The user can specify NULL for any parameter that is not needed.

3144:    Level: intermediate

3146: .keywords: SNES, nonlinear, get, convergence, tolerances

3148: .seealso: SNESSetTolerances()
3149: @*/
3150: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3151: {
3154:   if (atol)  *atol  = snes->abstol;
3155:   if (rtol)  *rtol  = snes->rtol;
3156:   if (stol)  *stol  = snes->stol;
3157:   if (maxit) *maxit = snes->max_its;
3158:   if (maxf)  *maxf  = snes->max_funcs;
3159:   return(0);
3160: }

3164: /*@
3165:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3167:    Logically Collective on SNES

3169:    Input Parameters:
3170: +  snes - the SNES context
3171: -  tol - tolerance

3173:    Options Database Key:
3174: .  -snes_trtol <tol> - Sets tol

3176:    Level: intermediate

3178: .keywords: SNES, nonlinear, set, trust region, tolerance

3180: .seealso: SNESSetTolerances()
3181: @*/
3182: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3183: {
3187:   snes->deltatol = tol;
3188:   return(0);
3189: }

3191: /*
3192:    Duplicate the lg monitors for SNES from KSP; for some reason with
3193:    dynamic libraries things don't work under Sun4 if we just use
3194:    macros instead of functions
3195: */
3198: PetscErrorCode  SNESMonitorLGResidualNorm(SNES snes,PetscInt it,PetscReal norm,void *ctx)
3199: {

3204:   KSPMonitorLGResidualNorm((KSP)snes,it,norm,ctx);
3205:   return(0);
3206: }

3210: PetscErrorCode  SNESMonitorLGCreate(const char host[],const char label[],int x,int y,int m,int n,PetscDrawLG *draw)
3211: {

3215:   KSPMonitorLGResidualNormCreate(host,label,x,y,m,n,draw);
3216:   return(0);
3217: }

3221: PetscErrorCode  SNESMonitorLGDestroy(PetscDrawLG *draw)
3222: {

3226:   KSPMonitorLGResidualNormDestroy(draw);
3227:   return(0);
3228: }

3230: extern PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);
3233: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3234: {
3235:   PetscDrawLG      lg;
3236:   PetscErrorCode   ierr;
3237:   PetscReal        x,y,per;
3238:   PetscViewer      v = (PetscViewer)monctx;
3239:   static PetscReal prev; /* should be in the context */
3240:   PetscDraw        draw;

3243:   PetscViewerDrawGetDrawLG(v,0,&lg);
3244:   if (!n) {PetscDrawLGReset(lg);}
3245:   PetscDrawLGGetDraw(lg,&draw);
3246:   PetscDrawSetTitle(draw,"Residual norm");
3247:   x    = (PetscReal)n;
3248:   if (rnorm > 0.0) y = log10(rnorm);
3249:   else y = -15.0;
3250:   PetscDrawLGAddPoint(lg,&x,&y);
3251:   if (n < 20 || !(n % 5)) {
3252:     PetscDrawLGDraw(lg);
3253:   }

3255:   PetscViewerDrawGetDrawLG(v,1,&lg);
3256:   if (!n) {PetscDrawLGReset(lg);}
3257:   PetscDrawLGGetDraw(lg,&draw);
3258:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3259:    SNESMonitorRange_Private(snes,n,&per);
3260:   x    = (PetscReal)n;
3261:   y    = 100.0*per;
3262:   PetscDrawLGAddPoint(lg,&x,&y);
3263:   if (n < 20 || !(n % 5)) {
3264:     PetscDrawLGDraw(lg);
3265:   }

3267:   PetscViewerDrawGetDrawLG(v,2,&lg);
3268:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3269:   PetscDrawLGGetDraw(lg,&draw);
3270:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3271:   x    = (PetscReal)n;
3272:   y    = (prev - rnorm)/prev;
3273:   PetscDrawLGAddPoint(lg,&x,&y);
3274:   if (n < 20 || !(n % 5)) {
3275:     PetscDrawLGDraw(lg);
3276:   }

3278:   PetscViewerDrawGetDrawLG(v,3,&lg);
3279:   if (!n) {PetscDrawLGReset(lg);}
3280:   PetscDrawLGGetDraw(lg,&draw);
3281:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3282:   x    = (PetscReal)n;
3283:   y    = (prev - rnorm)/(prev*per);
3284:   if (n > 2) { /*skip initial crazy value */
3285:     PetscDrawLGAddPoint(lg,&x,&y);
3286:   }
3287:   if (n < 20 || !(n % 5)) {
3288:     PetscDrawLGDraw(lg);
3289:   }
3290:   prev = rnorm;
3291:   return(0);
3292: }

3296: /*@
3297:    SNESMonitor - runs the user provided monitor routines, if they exist

3299:    Collective on SNES

3301:    Input Parameters:
3302: +  snes - nonlinear solver context obtained from SNESCreate()
3303: .  iter - iteration number
3304: -  rnorm - relative norm of the residual

3306:    Notes:
3307:    This routine is called by the SNES implementations.
3308:    It does not typically need to be called by the user.

3310:    Level: developer

3312: .seealso: SNESMonitorSet()
3313: @*/
3314: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3315: {
3317:   PetscInt       i,n = snes->numbermonitors;

3320:   for (i=0; i<n; i++) {
3321:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3322:   }
3323:   return(0);
3324: }

3326: /* ------------ Routines to set performance monitoring options ----------- */

3328: /*MC
3329:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3331:      Synopsis:
3332:      #include <petscsnes.h>
3333: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3335: +    snes - the SNES context
3336: .    its - iteration number
3337: .    norm - 2-norm function value (may be estimated)
3338: -    mctx - [optional] monitoring context

3340:    Level: advanced

3342: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3343: M*/

3347: /*@C
3348:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3349:    iteration of the nonlinear solver to display the iteration's
3350:    progress.

3352:    Logically Collective on SNES

3354:    Input Parameters:
3355: +  snes - the SNES context
3356: .  SNESMonitorFunction - monitoring routine
3357: .  mctx - [optional] user-defined context for private data for the
3358:           monitor routine (use NULL if no context is desired)
3359: -  monitordestroy - [optional] routine that frees monitor context
3360:           (may be NULL)

3362:    Options Database Keys:
3363: +    -snes_monitor        - sets SNESMonitorDefault()
3364: .    -snes_monitor_lg_residualnorm    - sets line graph monitor,
3365:                             uses SNESMonitorLGCreate()
3366: -    -snes_monitor_cancel - cancels all monitors that have
3367:                             been hardwired into a code by
3368:                             calls to SNESMonitorSet(), but
3369:                             does not cancel those set via
3370:                             the options database.

3372:    Notes:
3373:    Several different monitoring routines may be set by calling
3374:    SNESMonitorSet() multiple times; all will be called in the
3375:    order in which they were set.

3377:    Fortran notes: Only a single monitor function can be set for each SNES object

3379:    Level: intermediate

3381: .keywords: SNES, nonlinear, set, monitor

3383: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3384: @*/
3385: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*SNESMonitorFunction)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3386: {
3387:   PetscInt       i;

3392:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3393:   for (i=0; i<snes->numbermonitors;i++) {
3394:     if (SNESMonitorFunction == snes->monitor[i] && monitordestroy == snes->monitordestroy[i] && mctx == snes->monitorcontext[i]) {
3395:       if (monitordestroy) {
3396:         (*monitordestroy)(&mctx);
3397:       }
3398:       return(0);
3399:     }
3400:   }
3401:   snes->monitor[snes->numbermonitors]          = SNESMonitorFunction;
3402:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3403:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3404:   return(0);
3405: }

3409: /*@
3410:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3412:    Logically Collective on SNES

3414:    Input Parameters:
3415: .  snes - the SNES context

3417:    Options Database Key:
3418: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
3419:     into a code by calls to SNESMonitorSet(), but does not cancel those
3420:     set via the options database

3422:    Notes:
3423:    There is no way to clear one specific monitor from a SNES object.

3425:    Level: intermediate

3427: .keywords: SNES, nonlinear, set, monitor

3429: .seealso: SNESMonitorDefault(), SNESMonitorSet()
3430: @*/
3431: PetscErrorCode  SNESMonitorCancel(SNES snes)
3432: {
3434:   PetscInt       i;

3438:   for (i=0; i<snes->numbermonitors; i++) {
3439:     if (snes->monitordestroy[i]) {
3440:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
3441:     }
3442:   }
3443:   snes->numbermonitors = 0;
3444:   return(0);
3445: }

3447: /*MC
3448:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

3450:      Synopsis:
3451:      #include <petscsnes.h>
3452: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

3454: +    snes - the SNES context
3455: .    it - current iteration (0 is the first and is before any Newton step)
3456: .    cctx - [optional] convergence context
3457: .    reason - reason for convergence/divergence
3458: .    xnorm - 2-norm of current iterate
3459: .    gnorm - 2-norm of current step
3460: -    f - 2-norm of function

3462:    Level: intermediate

3464: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
3465: M*/

3469: /*@C
3470:    SNESSetConvergenceTest - Sets the function that is to be used
3471:    to test for convergence of the nonlinear iterative solution.

3473:    Logically Collective on SNES

3475:    Input Parameters:
3476: +  snes - the SNES context
3477: .  SNESConvergenceTestFunction - routine to test for convergence
3478: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
3479: -  destroy - [optional] destructor for the context (may be NULL; NULL_FUNCTION in Fortran)

3481:    Level: advanced

3483: .keywords: SNES, nonlinear, set, convergence, test

3485: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
3486: @*/
3487: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
3488: {

3493:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
3494:   if (snes->ops->convergeddestroy) {
3495:     (*snes->ops->convergeddestroy)(snes->cnvP);
3496:   }
3497:   snes->ops->converged        = SNESConvergenceTestFunction;
3498:   snes->ops->convergeddestroy = destroy;
3499:   snes->cnvP                  = cctx;
3500:   return(0);
3501: }

3505: /*@
3506:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

3508:    Not Collective

3510:    Input Parameter:
3511: .  snes - the SNES context

3513:    Output Parameter:
3514: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3515:             manual pages for the individual convergence tests for complete lists

3517:    Level: intermediate

3519:    Notes: Can only be called after the call the SNESSolve() is complete.

3521: .keywords: SNES, nonlinear, set, convergence, test

3523: .seealso: SNESSetConvergenceTest(), SNESConvergedReason
3524: @*/
3525: PetscErrorCode  SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
3526: {
3530:   *reason = snes->reason;
3531:   return(0);
3532: }

3536: /*@
3537:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

3539:    Logically Collective on SNES

3541:    Input Parameters:
3542: +  snes - iterative context obtained from SNESCreate()
3543: .  a   - array to hold history, this array will contain the function norms computed at each step
3544: .  its - integer array holds the number of linear iterations for each solve.
3545: .  na  - size of a and its
3546: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
3547:            else it continues storing new values for new nonlinear solves after the old ones

3549:    Notes:
3550:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
3551:    default array of length 10000 is allocated.

3553:    This routine is useful, e.g., when running a code for purposes
3554:    of accurate performance monitoring, when no I/O should be done
3555:    during the section of code that is being timed.

3557:    Level: intermediate

3559: .keywords: SNES, set, convergence, history

3561: .seealso: SNESGetConvergenceHistory()

3563: @*/
3564: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
3565: {

3572:   if (!a) {
3573:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
3574:     PetscMalloc1(na,&a);
3575:     PetscMalloc1(na,&its);

3577:     snes->conv_malloc = PETSC_TRUE;
3578:   }
3579:   snes->conv_hist       = a;
3580:   snes->conv_hist_its   = its;
3581:   snes->conv_hist_max   = na;
3582:   snes->conv_hist_len   = 0;
3583:   snes->conv_hist_reset = reset;
3584:   return(0);
3585: }

3587: #if defined(PETSC_HAVE_MATLAB_ENGINE)
3588: #include <engine.h>   /* MATLAB include file */
3589: #include <mex.h>      /* MATLAB include file */

3593: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
3594: {
3595:   mxArray   *mat;
3596:   PetscInt  i;
3597:   PetscReal *ar;

3600:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
3601:   ar  = (PetscReal*) mxGetData(mat);
3602:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
3603:   PetscFunctionReturn(mat);
3604: }
3605: #endif

3609: /*@C
3610:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

3612:    Not Collective

3614:    Input Parameter:
3615: .  snes - iterative context obtained from SNESCreate()

3617:    Output Parameters:
3618: .  a   - array to hold history
3619: .  its - integer array holds the number of linear iterations (or
3620:          negative if not converged) for each solve.
3621: -  na  - size of a and its

3623:    Notes:
3624:     The calling sequence for this routine in Fortran is
3625: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

3627:    This routine is useful, e.g., when running a code for purposes
3628:    of accurate performance monitoring, when no I/O should be done
3629:    during the section of code that is being timed.

3631:    Level: intermediate

3633: .keywords: SNES, get, convergence, history

3635: .seealso: SNESSetConvergencHistory()

3637: @*/
3638: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
3639: {
3642:   if (a)   *a   = snes->conv_hist;
3643:   if (its) *its = snes->conv_hist_its;
3644:   if (na)  *na  = snes->conv_hist_len;
3645:   return(0);
3646: }

3650: /*@C
3651:   SNESSetUpdate - Sets the general-purpose update function called
3652:   at the beginning of every iteration of the nonlinear solve. Specifically
3653:   it is called just before the Jacobian is "evaluated".

3655:   Logically Collective on SNES

3657:   Input Parameters:
3658: . snes - The nonlinear solver context
3659: . func - The function

3661:   Calling sequence of func:
3662: . func (SNES snes, PetscInt step);

3664: . step - The current step of the iteration

3666:   Level: advanced

3668:   Note: This is NOT what one uses to update the ghost points before a function evaluation, that should be done at the beginning of your FormFunction()
3669:         This is not used by most users.

3671: .keywords: SNES, update

3673: .seealso SNESSetJacobian(), SNESSolve()
3674: @*/
3675: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
3676: {
3679:   snes->ops->update = func;
3680:   return(0);
3681: }

3685: /*
3686:    SNESScaleStep_Private - Scales a step so that its length is less than the
3687:    positive parameter delta.

3689:     Input Parameters:
3690: +   snes - the SNES context
3691: .   y - approximate solution of linear system
3692: .   fnorm - 2-norm of current function
3693: -   delta - trust region size

3695:     Output Parameters:
3696: +   gpnorm - predicted function norm at the new point, assuming local
3697:     linearization.  The value is zero if the step lies within the trust
3698:     region, and exceeds zero otherwise.
3699: -   ynorm - 2-norm of the step

3701:     Note:
3702:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
3703:     is set to be the maximum allowable step size.

3705: .keywords: SNES, nonlinear, scale, step
3706: */
3707: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
3708: {
3709:   PetscReal      nrm;
3710:   PetscScalar    cnorm;


3718:   VecNorm(y,NORM_2,&nrm);
3719:   if (nrm > *delta) {
3720:     nrm     = *delta/nrm;
3721:     *gpnorm = (1.0 - nrm)*(*fnorm);
3722:     cnorm   = nrm;
3723:     VecScale(y,cnorm);
3724:     *ynorm  = *delta;
3725:   } else {
3726:     *gpnorm = 0.0;
3727:     *ynorm  = nrm;
3728:   }
3729:   return(0);
3730: }

3734: /*@C
3735:    SNESSolve - Solves a nonlinear system F(x) = b.
3736:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

3738:    Collective on SNES

3740:    Input Parameters:
3741: +  snes - the SNES context
3742: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
3743: -  x - the solution vector.

3745:    Notes:
3746:    The user should initialize the vector,x, with the initial guess
3747:    for the nonlinear solve prior to calling SNESSolve.  In particular,
3748:    to employ an initial guess of zero, the user should explicitly set
3749:    this vector to zero by calling VecSet().

3751:    Level: beginner

3753: .keywords: SNES, nonlinear, solve

3755: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
3756: @*/
3757: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
3758: {
3759:   PetscErrorCode    ierr;
3760:   PetscBool         flg;
3761:   PetscInt          grid;
3762:   Vec               xcreated = NULL;
3763:   DM                dm;


3772:   if (!x) {
3773:     SNESGetDM(snes,&dm);
3774:     DMCreateGlobalVector(dm,&xcreated);
3775:     x    = xcreated;
3776:   }
3777:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

3779:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
3780:   for (grid=0; grid<snes->gridsequence+1; grid++) {

3782:     /* set solution vector */
3783:     if (!grid) {PetscObjectReference((PetscObject)x);}
3784:     VecDestroy(&snes->vec_sol);
3785:     snes->vec_sol = x;
3786:     SNESGetDM(snes,&dm);

3788:     /* set affine vector if provided */
3789:     if (b) { PetscObjectReference((PetscObject)b); }
3790:     VecDestroy(&snes->vec_rhs);
3791:     snes->vec_rhs = b;

3793:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
3794:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
3795:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
3796:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
3797:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
3798:     }
3799:     DMShellSetGlobalVector(dm,snes->vec_sol);
3800:     SNESSetUp(snes);

3802:     if (!grid) {
3803:       if (snes->ops->computeinitialguess) {
3804:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
3805:       }
3806:     }

3808:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
3809:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

3811:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
3812:     (*snes->ops->solve)(snes);
3813:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
3814:     if (snes->domainerror) {
3815:       snes->reason      = SNES_DIVERGED_FUNCTION_DOMAIN;
3816:       snes->domainerror = PETSC_FALSE;
3817:     }
3818:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");

3820:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
3821:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

3823:     flg  = PETSC_FALSE;
3824:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_test_local_min",&flg,NULL);
3825:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
3826:     if (snes->printreason) {
3827:       PetscViewerASCIIAddTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)),((PetscObject)snes)->tablevel);
3828:       if (snes->reason > 0) {
3829:         PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)),"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
3830:       } else {
3831:         PetscViewerASCIIPrintf(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)),"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
3832:       }
3833:       PetscViewerASCIISubtractTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)),((PetscObject)snes)->tablevel);
3834:     }

3836:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
3837:     if (grid <  snes->gridsequence) {
3838:       DM  fine;
3839:       Vec xnew;
3840:       Mat interp;

3842:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
3843:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
3844:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
3845:       DMCreateGlobalVector(fine,&xnew);
3846:       MatInterpolate(interp,x,xnew);
3847:       DMInterpolate(snes->dm,interp,fine);
3848:       MatDestroy(&interp);
3849:       x    = xnew;

3851:       SNESReset(snes);
3852:       SNESSetDM(snes,fine);
3853:       DMDestroy(&fine);
3854:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
3855:     }
3856:   }
3857:   SNESViewFromOptions(snes,NULL,"-snes_view");
3858:   VecViewFromOptions(snes->vec_sol,((PetscObject)snes)->prefix,"-snes_view_solution");

3860:   VecDestroy(&xcreated);
3861:   PetscObjectSAWsBlock((PetscObject)snes);
3862:   return(0);
3863: }

3865: /* --------- Internal routines for SNES Package --------- */

3869: /*@C
3870:    SNESSetType - Sets the method for the nonlinear solver.

3872:    Collective on SNES

3874:    Input Parameters:
3875: +  snes - the SNES context
3876: -  type - a known method

3878:    Options Database Key:
3879: .  -snes_type <type> - Sets the method; use -help for a list
3880:    of available methods (for instance, newtonls or newtontr)

3882:    Notes:
3883:    See "petsc/include/petscsnes.h" for available methods (for instance)
3884: +    SNESNEWTONLS - Newton's method with line search
3885:      (systems of nonlinear equations)
3886: .    SNESNEWTONTR - Newton's method with trust region
3887:      (systems of nonlinear equations)

3889:   Normally, it is best to use the SNESSetFromOptions() command and then
3890:   set the SNES solver type from the options database rather than by using
3891:   this routine.  Using the options database provides the user with
3892:   maximum flexibility in evaluating the many nonlinear solvers.
3893:   The SNESSetType() routine is provided for those situations where it
3894:   is necessary to set the nonlinear solver independently of the command
3895:   line or options database.  This might be the case, for example, when
3896:   the choice of solver changes during the execution of the program,
3897:   and the user's application is taking responsibility for choosing the
3898:   appropriate method.

3900:     Developer Notes: SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
3901:     the constructor in that list and calls it to create the spexific object.

3903:   Level: intermediate

3905: .keywords: SNES, set, type

3907: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

3909: @*/
3910: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
3911: {
3912:   PetscErrorCode ierr,(*r)(SNES);
3913:   PetscBool      match;


3919:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
3920:   if (match) return(0);

3922:    PetscFunctionListFind(SNESList,type,&r);
3923:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
3924:   /* Destroy the previous private SNES context */
3925:   if (snes->ops->destroy) {
3926:     (*(snes)->ops->destroy)(snes);
3927:     snes->ops->destroy = NULL;
3928:   }
3929:   /* Reinitialize function pointers in SNESOps structure */
3930:   snes->ops->setup          = 0;
3931:   snes->ops->solve          = 0;
3932:   snes->ops->view           = 0;
3933:   snes->ops->setfromoptions = 0;
3934:   snes->ops->destroy        = 0;
3935:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
3936:   snes->setupcalled = PETSC_FALSE;

3938:   PetscObjectChangeTypeName((PetscObject)snes,type);
3939:   (*r)(snes);
3940:   return(0);
3941: }

3945: /*@C
3946:    SNESGetType - Gets the SNES method type and name (as a string).

3948:    Not Collective

3950:    Input Parameter:
3951: .  snes - nonlinear solver context

3953:    Output Parameter:
3954: .  type - SNES method (a character string)

3956:    Level: intermediate

3958: .keywords: SNES, nonlinear, get, type, name
3959: @*/
3960: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
3961: {
3965:   *type = ((PetscObject)snes)->type_name;
3966:   return(0);
3967: }

3971: /*@
3972:    SNESGetSolution - Returns the vector where the approximate solution is
3973:    stored. This is the fine grid solution when using SNESSetGridSequence().

3975:    Not Collective, but Vec is parallel if SNES is parallel

3977:    Input Parameter:
3978: .  snes - the SNES context

3980:    Output Parameter:
3981: .  x - the solution

3983:    Level: intermediate

3985: .keywords: SNES, nonlinear, get, solution

3987: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
3988: @*/
3989: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
3990: {
3994:   *x = snes->vec_sol;
3995:   return(0);
3996: }

4000: /*@
4001:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4002:    stored.

4004:    Not Collective, but Vec is parallel if SNES is parallel

4006:    Input Parameter:
4007: .  snes - the SNES context

4009:    Output Parameter:
4010: .  x - the solution update

4012:    Level: advanced

4014: .keywords: SNES, nonlinear, get, solution, update

4016: .seealso: SNESGetSolution(), SNESGetFunction()
4017: @*/
4018: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4019: {
4023:   *x = snes->vec_sol_update;
4024:   return(0);
4025: }

4029: /*@C
4030:    SNESGetFunction - Returns the vector where the function is stored.

4032:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4034:    Input Parameter:
4035: .  snes - the SNES context

4037:    Output Parameter:
4038: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4039: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4040: -  ctx - the function context (or NULL if you don't want it)

4042:    Level: advanced

4044: .keywords: SNES, nonlinear, get, function

4046: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4047: @*/
4048: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4049: {
4051:   DM             dm;

4055:   if (r) {
4056:     if (!snes->vec_func) {
4057:       if (snes->vec_rhs) {
4058:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4059:       } else if (snes->vec_sol) {
4060:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4061:       } else if (snes->dm) {
4062:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4063:       }
4064:     }
4065:     *r = snes->vec_func;
4066:   }
4067:   SNESGetDM(snes,&dm);
4068:   DMSNESGetFunction(dm,f,ctx);
4069:   return(0);
4070: }

4072: /*@C
4073:    SNESGetGS - Returns the GS function and context.

4075:    Input Parameter:
4076: .  snes - the SNES context

4078:    Output Parameter:
4079: +  SNESGSFunction - the function (or NULL)
4080: -  ctx    - the function context (or NULL)

4082:    Level: advanced

4084: .keywords: SNES, nonlinear, get, function

4086: .seealso: SNESSetGS(), SNESGetFunction()
4087: @*/

4091: PetscErrorCode SNESGetGS (SNES snes, PetscErrorCode (**SNESGSFunction)(SNES, Vec, Vec, void*), void ** ctx)
4092: {
4094:   DM             dm;

4098:   SNESGetDM(snes,&dm);
4099:   DMSNESGetGS(dm,SNESGSFunction,ctx);
4100:   return(0);
4101: }

4105: /*@C
4106:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4107:    SNES options in the database.

4109:    Logically Collective on SNES

4111:    Input Parameter:
4112: +  snes - the SNES context
4113: -  prefix - the prefix to prepend to all option names

4115:    Notes:
4116:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4117:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4119:    Level: advanced

4121: .keywords: SNES, set, options, prefix, database

4123: .seealso: SNESSetFromOptions()
4124: @*/
4125: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4126: {

4131:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4132:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4133:   if (snes->linesearch) {
4134:     SNESGetLineSearch(snes,&snes->linesearch);
4135:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4136:   }
4137:   KSPSetOptionsPrefix(snes->ksp,prefix);
4138:   return(0);
4139: }

4143: /*@C
4144:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4145:    SNES options in the database.

4147:    Logically Collective on SNES

4149:    Input Parameters:
4150: +  snes - the SNES context
4151: -  prefix - the prefix to prepend to all option names

4153:    Notes:
4154:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4155:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4157:    Level: advanced

4159: .keywords: SNES, append, options, prefix, database

4161: .seealso: SNESGetOptionsPrefix()
4162: @*/
4163: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
4164: {

4169:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
4170:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4171:   if (snes->linesearch) {
4172:     SNESGetLineSearch(snes,&snes->linesearch);
4173:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
4174:   }
4175:   KSPAppendOptionsPrefix(snes->ksp,prefix);
4176:   return(0);
4177: }

4181: /*@C
4182:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
4183:    SNES options in the database.

4185:    Not Collective

4187:    Input Parameter:
4188: .  snes - the SNES context

4190:    Output Parameter:
4191: .  prefix - pointer to the prefix string used

4193:    Notes: On the fortran side, the user should pass in a string 'prefix' of
4194:    sufficient length to hold the prefix.

4196:    Level: advanced

4198: .keywords: SNES, get, options, prefix, database

4200: .seealso: SNESAppendOptionsPrefix()
4201: @*/
4202: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
4203: {

4208:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
4209:   return(0);
4210: }


4215: /*@C
4216:   SNESRegister - Adds a method to the nonlinear solver package.

4218:    Not collective

4220:    Input Parameters:
4221: +  name_solver - name of a new user-defined solver
4222: -  routine_create - routine to create method context

4224:    Notes:
4225:    SNESRegister() may be called multiple times to add several user-defined solvers.

4227:    Sample usage:
4228: .vb
4229:    SNESRegister("my_solver",MySolverCreate);
4230: .ve

4232:    Then, your solver can be chosen with the procedural interface via
4233: $     SNESSetType(snes,"my_solver")
4234:    or at runtime via the option
4235: $     -snes_type my_solver

4237:    Level: advanced

4239:     Note: If your function is not being put into a shared library then use SNESRegister() instead

4241: .keywords: SNES, nonlinear, register

4243: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

4245:   Level: advanced
4246: @*/
4247: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
4248: {

4252:   PetscFunctionListAdd(&SNESList,sname,function);
4253:   return(0);
4254: }

4258: PetscErrorCode  SNESTestLocalMin(SNES snes)
4259: {
4261:   PetscInt       N,i,j;
4262:   Vec            u,uh,fh;
4263:   PetscScalar    value;
4264:   PetscReal      norm;

4267:   SNESGetSolution(snes,&u);
4268:   VecDuplicate(u,&uh);
4269:   VecDuplicate(u,&fh);

4271:   /* currently only works for sequential */
4272:   PetscPrintf(PETSC_COMM_WORLD,"Testing FormFunction() for local min\n");
4273:   VecGetSize(u,&N);
4274:   for (i=0; i<N; i++) {
4275:     VecCopy(u,uh);
4276:     PetscPrintf(PETSC_COMM_WORLD,"i = %D\n",i);
4277:     for (j=-10; j<11; j++) {
4278:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
4279:       VecSetValue(uh,i,value,ADD_VALUES);
4280:       SNESComputeFunction(snes,uh,fh);
4281:       VecNorm(fh,NORM_2,&norm);
4282:       PetscPrintf(PETSC_COMM_WORLD,"       j norm %D %18.16e\n",j,norm);
4283:       value = -value;
4284:       VecSetValue(uh,i,value,ADD_VALUES);
4285:     }
4286:   }
4287:   VecDestroy(&uh);
4288:   VecDestroy(&fh);
4289:   return(0);
4290: }

4294: /*@
4295:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
4296:    computing relative tolerance for linear solvers within an inexact
4297:    Newton method.

4299:    Logically Collective on SNES

4301:    Input Parameters:
4302: +  snes - SNES context
4303: -  flag - PETSC_TRUE or PETSC_FALSE

4305:     Options Database:
4306: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
4307: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
4308: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
4309: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
4310: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
4311: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
4312: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
4313: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

4315:    Notes:
4316:    Currently, the default is to use a constant relative tolerance for
4317:    the inner linear solvers.  Alternatively, one can use the
4318:    Eisenstat-Walker method, where the relative convergence tolerance
4319:    is reset at each Newton iteration according progress of the nonlinear
4320:    solver.

4322:    Level: advanced

4324:    Reference:
4325:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4326:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4328: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4330: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4331: @*/
4332: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
4333: {
4337:   snes->ksp_ewconv = flag;
4338:   return(0);
4339: }

4343: /*@
4344:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
4345:    for computing relative tolerance for linear solvers within an
4346:    inexact Newton method.

4348:    Not Collective

4350:    Input Parameter:
4351: .  snes - SNES context

4353:    Output Parameter:
4354: .  flag - PETSC_TRUE or PETSC_FALSE

4356:    Notes:
4357:    Currently, the default is to use a constant relative tolerance for
4358:    the inner linear solvers.  Alternatively, one can use the
4359:    Eisenstat-Walker method, where the relative convergence tolerance
4360:    is reset at each Newton iteration according progress of the nonlinear
4361:    solver.

4363:    Level: advanced

4365:    Reference:
4366:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4367:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4369: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4371: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4372: @*/
4373: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
4374: {
4378:   *flag = snes->ksp_ewconv;
4379:   return(0);
4380: }

4384: /*@
4385:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
4386:    convergence criteria for the linear solvers within an inexact
4387:    Newton method.

4389:    Logically Collective on SNES

4391:    Input Parameters:
4392: +    snes - SNES context
4393: .    version - version 1, 2 (default is 2) or 3
4394: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4395: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4396: .    gamma - multiplicative factor for version 2 rtol computation
4397:              (0 <= gamma2 <= 1)
4398: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4399: .    alpha2 - power for safeguard
4400: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4402:    Note:
4403:    Version 3 was contributed by Luis Chacon, June 2006.

4405:    Use PETSC_DEFAULT to retain the default for any of the parameters.

4407:    Level: advanced

4409:    Reference:
4410:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4411:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
4412:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

4414: .keywords: SNES, KSP, Eisenstat, Walker, set, parameters

4416: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
4417: @*/
4418: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
4419: {
4420:   SNESKSPEW *kctx;

4424:   kctx = (SNESKSPEW*)snes->kspconvctx;
4425:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

4434:   if (version != PETSC_DEFAULT)   kctx->version   = version;
4435:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
4436:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
4437:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
4438:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
4439:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
4440:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

4442:   if (kctx->version < 1 || kctx->version > 3) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 and 3 are supported: %D",kctx->version);
4443:   if (kctx->rtol_0 < 0.0 || kctx->rtol_0 >= 1.0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"0.0 <= rtol_0 < 1.0: %g",(double)kctx->rtol_0);
4444:   if (kctx->rtol_max < 0.0 || kctx->rtol_max >= 1.0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"0.0 <= rtol_max (%g) < 1.0\n",(double)kctx->rtol_max);
4445:   if (kctx->gamma < 0.0 || kctx->gamma > 1.0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"0.0 <= gamma (%g) <= 1.0\n",(double)kctx->gamma);
4446:   if (kctx->alpha <= 1.0 || kctx->alpha > 2.0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"1.0 < alpha (%g) <= 2.0\n",(double)kctx->alpha);
4447:   if (kctx->threshold <= 0.0 || kctx->threshold >= 1.0) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"0.0 < threshold (%g) < 1.0\n",(double)kctx->threshold);
4448:   return(0);
4449: }

4453: /*@
4454:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
4455:    convergence criteria for the linear solvers within an inexact
4456:    Newton method.

4458:    Not Collective

4460:    Input Parameters:
4461:      snes - SNES context

4463:    Output Parameters:
4464: +    version - version 1, 2 (default is 2) or 3
4465: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4466: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4467: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
4468: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4469: .    alpha2 - power for safeguard
4470: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4472:    Level: advanced

4474: .keywords: SNES, KSP, Eisenstat, Walker, get, parameters

4476: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
4477: @*/
4478: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
4479: {
4480:   SNESKSPEW *kctx;

4484:   kctx = (SNESKSPEW*)snes->kspconvctx;
4485:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
4486:   if (version)   *version   = kctx->version;
4487:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
4488:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
4489:   if (gamma)     *gamma     = kctx->gamma;
4490:   if (alpha)     *alpha     = kctx->alpha;
4491:   if (alpha2)    *alpha2    = kctx->alpha2;
4492:   if (threshold) *threshold = kctx->threshold;
4493:   return(0);
4494: }

4498:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
4499: {
4501:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
4502:   PetscReal      rtol  = PETSC_DEFAULT,stol;

4505:   if (!snes->ksp_ewconv) return(0);
4506:   if (!snes->iter) {
4507:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
4508:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
4509:   }
4510:   else {
4511:     if (kctx->version == 1) {
4512:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
4513:       if (rtol < 0.0) rtol = -rtol;
4514:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
4515:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
4516:     } else if (kctx->version == 2) {
4517:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
4518:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
4519:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
4520:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
4521:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
4522:       /* safeguard: avoid sharp decrease of rtol */
4523:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
4524:       stol = PetscMax(rtol,stol);
4525:       rtol = PetscMin(kctx->rtol_0,stol);
4526:       /* safeguard: avoid oversolving */
4527:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
4528:       stol = PetscMax(rtol,stol);
4529:       rtol = PetscMin(kctx->rtol_0,stol);
4530:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
4531:   }
4532:   /* safeguard: avoid rtol greater than one */
4533:   rtol = PetscMin(rtol,kctx->rtol_max);
4534:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
4535:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
4536:   return(0);
4537: }

4541: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
4542: {
4544:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
4545:   PCSide         pcside;
4546:   Vec            lres;

4549:   if (!snes->ksp_ewconv) return(0);
4550:   KSPGetTolerances(ksp,&kctx->rtol_last,0,0,0);
4551:   SNESGetFunctionNorm(snes,&kctx->norm_last);
4552:   if (kctx->version == 1) {
4553:     KSPGetPCSide(ksp,&pcside);
4554:     if (pcside == PC_RIGHT) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
4555:       /* KSP residual is true linear residual */
4556:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
4557:     } else {
4558:       /* KSP residual is preconditioned residual */
4559:       /* compute true linear residual norm */
4560:       VecDuplicate(b,&lres);
4561:       MatMult(snes->jacobian,x,lres);
4562:       VecAYPX(lres,-1.0,b);
4563:       VecNorm(lres,NORM_2,&kctx->lresid_last);
4564:       VecDestroy(&lres);
4565:     }
4566:   }
4567:   return(0);
4568: }

4572: /*@
4573:    SNESGetKSP - Returns the KSP context for a SNES solver.

4575:    Not Collective, but if SNES object is parallel, then KSP object is parallel

4577:    Input Parameter:
4578: .  snes - the SNES context

4580:    Output Parameter:
4581: .  ksp - the KSP context

4583:    Notes:
4584:    The user can then directly manipulate the KSP context to set various
4585:    options, etc.  Likewise, the user can then extract and manipulate the
4586:    PC contexts as well.

4588:    Level: beginner

4590: .keywords: SNES, nonlinear, get, KSP, context

4592: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
4593: @*/
4594: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
4595: {


4602:   if (!snes->ksp) {
4603:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
4604:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
4605:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

4607:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
4608:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);
4609:   }
4610:   *ksp = snes->ksp;
4611:   return(0);
4612: }


4615: #include <petsc-private/dmimpl.h>
4618: /*@
4619:    SNESSetDM - Sets the DM that may be used by some preconditioners

4621:    Logically Collective on SNES

4623:    Input Parameters:
4624: +  snes - the preconditioner context
4625: -  dm - the dm

4627:    Level: intermediate

4629: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
4630: @*/
4631: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
4632: {
4634:   KSP            ksp;
4635:   DMSNES         sdm;

4639:   if (dm) {PetscObjectReference((PetscObject)dm);}
4640:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
4641:     if (snes->dm->dmsnes && snes->dmAuto && !dm->dmsnes) {
4642:       DMCopyDMSNES(snes->dm,dm);
4643:       DMGetDMSNES(snes->dm,&sdm);
4644:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
4645:     }
4646:     DMDestroy(&snes->dm);
4647:   }
4648:   snes->dm     = dm;
4649:   snes->dmAuto = PETSC_FALSE;

4651:   SNESGetKSP(snes,&ksp);
4652:   KSPSetDM(ksp,dm);
4653:   KSPSetDMActive(ksp,PETSC_FALSE);
4654:   if (snes->pc) {
4655:     SNESSetDM(snes->pc, snes->dm);
4656:     SNESSetPCSide(snes,snes->pcside);
4657:   }
4658:   return(0);
4659: }

4663: /*@
4664:    SNESGetDM - Gets the DM that may be used by some preconditioners

4666:    Not Collective but DM obtained is parallel on SNES

4668:    Input Parameter:
4669: . snes - the preconditioner context

4671:    Output Parameter:
4672: .  dm - the dm

4674:    Level: intermediate

4676: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
4677: @*/
4678: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
4679: {

4684:   if (!snes->dm) {
4685:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
4686:     snes->dmAuto = PETSC_TRUE;
4687:   }
4688:   *dm = snes->dm;
4689:   return(0);
4690: }

4694: /*@
4695:   SNESSetPC - Sets the nonlinear preconditioner to be used.

4697:   Collective on SNES

4699:   Input Parameters:
4700: + snes - iterative context obtained from SNESCreate()
4701: - pc   - the preconditioner object

4703:   Notes:
4704:   Use SNESGetPC() to retrieve the preconditioner context (for example,
4705:   to configure it using the API).

4707:   Level: developer

4709: .keywords: SNES, set, precondition
4710: .seealso: SNESGetPC()
4711: @*/
4712: PetscErrorCode SNESSetPC(SNES snes, SNES pc)
4713: {

4720:   PetscObjectReference((PetscObject) pc);
4721:   SNESDestroy(&snes->pc);
4722:   snes->pc = pc;
4723:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->pc);
4724:   return(0);
4725: }

4729: /*@
4730:   SNESGetPC - Returns a pointer to the nonlinear preconditioning context set with SNESSetPC().

4732:   Not Collective

4734:   Input Parameter:
4735: . snes - iterative context obtained from SNESCreate()

4737:   Output Parameter:
4738: . pc - preconditioner context

4740:   Level: developer

4742: .keywords: SNES, get, preconditioner
4743: .seealso: SNESSetPC()
4744: @*/
4745: PetscErrorCode SNESGetPC(SNES snes, SNES *pc)
4746: {
4748:   const char     *optionsprefix;

4753:   if (!snes->pc) {
4754:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->pc);
4755:     PetscObjectIncrementTabLevel((PetscObject)snes->pc,(PetscObject)snes,1);
4756:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->pc);
4757:     SNESGetOptionsPrefix(snes,&optionsprefix);
4758:     SNESSetOptionsPrefix(snes->pc,optionsprefix);
4759:     SNESAppendOptionsPrefix(snes->pc,"npc_");
4760:     SNESSetCountersReset(snes->pc,PETSC_FALSE);
4761:   }
4762:   *pc = snes->pc;
4763:   return(0);
4764: }

4768: /*@
4769:     SNESSetPCSide - Sets the preconditioning side.

4771:     Logically Collective on SNES

4773:     Input Parameter:
4774: .   snes - iterative context obtained from SNESCreate()

4776:     Output Parameter:
4777: .   side - the preconditioning side, where side is one of
4778: .vb
4779:       PC_LEFT - left preconditioning (default)
4780:       PC_RIGHT - right preconditioning
4781: .ve

4783:     Options Database Keys:
4784: .   -snes_pc_side <right,left>

4786:     Level: intermediate

4788: .keywords: SNES, set, right, left, side, preconditioner, flag

4790: .seealso: SNESGetPCSide(), KSPSetPCSide()
4791: @*/
4792: PetscErrorCode  SNESSetPCSide(SNES snes,PCSide side)
4793: {
4797:   snes->pcside = side;
4798:   return(0);
4799: }

4803: /*@
4804:     SNESGetPCSide - Gets the preconditioning side.

4806:     Not Collective

4808:     Input Parameter:
4809: .   snes - iterative context obtained from SNESCreate()

4811:     Output Parameter:
4812: .   side - the preconditioning side, where side is one of
4813: .vb
4814:       PC_LEFT - left preconditioning (default)
4815:       PC_RIGHT - right preconditioning
4816: .ve

4818:     Level: intermediate

4820: .keywords: SNES, get, right, left, side, preconditioner, flag

4822: .seealso: SNESSetPCSide(), KSPGetPCSide()
4823: @*/
4824: PetscErrorCode  SNESGetPCSide(SNES snes,PCSide *side)
4825: {
4829:   *side = snes->pcside;
4830:   return(0);
4831: }

4835: /*@
4836:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

4838:   Collective on SNES

4840:   Input Parameters:
4841: + snes - iterative context obtained from SNESCreate()
4842: - linesearch   - the linesearch object

4844:   Notes:
4845:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
4846:   to configure it using the API).

4848:   Level: developer

4850: .keywords: SNES, set, linesearch
4851: .seealso: SNESGetLineSearch()
4852: @*/
4853: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
4854: {

4861:   PetscObjectReference((PetscObject) linesearch);
4862:   SNESLineSearchDestroy(&snes->linesearch);

4864:   snes->linesearch = linesearch;

4866:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
4867:   return(0);
4868: }

4872: /*@
4873:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
4874:   or creates a default line search instance associated with the SNES and returns it.

4876:   Not Collective

4878:   Input Parameter:
4879: . snes - iterative context obtained from SNESCreate()

4881:   Output Parameter:
4882: . linesearch - linesearch context

4884:   Level: developer

4886: .keywords: SNES, get, linesearch
4887: .seealso: SNESSetLineSearch()
4888: @*/
4889: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
4890: {
4892:   const char     *optionsprefix;

4897:   if (!snes->linesearch) {
4898:     SNESGetOptionsPrefix(snes, &optionsprefix);
4899:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
4900:     SNESLineSearchSetSNES(snes->linesearch, snes);
4901:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
4902:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
4903:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
4904:   }
4905:   *linesearch = snes->linesearch;
4906:   return(0);
4907: }

4909: #if defined(PETSC_HAVE_MATLAB_ENGINE)
4910: #include <mex.h>

4912: typedef struct {char *funcname; mxArray *ctx;} SNESMatlabContext;

4916: /*
4917:    SNESComputeFunction_Matlab - Calls the function that has been set with SNESSetFunctionMatlab().

4919:    Collective on SNES

4921:    Input Parameters:
4922: +  snes - the SNES context
4923: -  x - input vector

4925:    Output Parameter:
4926: .  y - function vector, as set by SNESSetFunction()

4928:    Notes:
4929:    SNESComputeFunction() is typically used within nonlinear solvers
4930:    implementations, so most users would not generally call this routine
4931:    themselves.

4933:    Level: developer

4935: .keywords: SNES, nonlinear, compute, function

4937: .seealso: SNESSetFunction(), SNESGetFunction()
4938: */
4939: PetscErrorCode  SNESComputeFunction_Matlab(SNES snes,Vec x,Vec y, void *ctx)
4940: {
4941:   PetscErrorCode    ierr;
4942:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
4943:   int               nlhs  = 1,nrhs = 5;
4944:   mxArray           *plhs[1],*prhs[5];
4945:   long long int     lx = 0,ly = 0,ls = 0;


4954:   /* call Matlab function in ctx with arguments x and y */

4956:   PetscMemcpy(&ls,&snes,sizeof(snes));
4957:   PetscMemcpy(&lx,&x,sizeof(x));
4958:   PetscMemcpy(&ly,&y,sizeof(x));
4959:   prhs[0] = mxCreateDoubleScalar((double)ls);
4960:   prhs[1] = mxCreateDoubleScalar((double)lx);
4961:   prhs[2] = mxCreateDoubleScalar((double)ly);
4962:   prhs[3] = mxCreateString(sctx->funcname);
4963:   prhs[4] = sctx->ctx;
4964:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeFunctionInternal");
4965:   mxGetScalar(plhs[0]);
4966:   mxDestroyArray(prhs[0]);
4967:   mxDestroyArray(prhs[1]);
4968:   mxDestroyArray(prhs[2]);
4969:   mxDestroyArray(prhs[3]);
4970:   mxDestroyArray(plhs[0]);
4971:   return(0);
4972: }

4976: /*
4977:    SNESSetFunctionMatlab - Sets the function evaluation routine and function
4978:    vector for use by the SNES routines in solving systems of nonlinear
4979:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

4981:    Logically Collective on SNES

4983:    Input Parameters:
4984: +  snes - the SNES context
4985: .  r - vector to store function value
4986: -  f - function evaluation routine

4988:    Notes:
4989:    The Newton-like methods typically solve linear systems of the form
4990: $      f'(x) x = -f(x),
4991:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

4993:    Level: beginner

4995:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

4997: .keywords: SNES, nonlinear, set, function

4999: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5000: */
5001: PetscErrorCode  SNESSetFunctionMatlab(SNES snes,Vec r,const char *f,mxArray *ctx)
5002: {
5003:   PetscErrorCode    ierr;
5004:   SNESMatlabContext *sctx;

5007:   /* currently sctx is memory bleed */
5008:   PetscMalloc(sizeof(SNESMatlabContext),&sctx);
5009:   PetscStrallocpy(f,&sctx->funcname);
5010:   /*
5011:      This should work, but it doesn't
5012:   sctx->ctx = ctx;
5013:   mexMakeArrayPersistent(sctx->ctx);
5014:   */
5015:   sctx->ctx = mxDuplicateArray(ctx);
5016:   SNESSetFunction(snes,r,SNESComputeFunction_Matlab,sctx);
5017:   return(0);
5018: }

5022: /*
5023:    SNESComputeJacobian_Matlab - Calls the function that has been set with SNESSetJacobianMatlab().

5025:    Collective on SNES

5027:    Input Parameters:
5028: +  snes - the SNES context
5029: .  x - input vector
5030: .  A, B - the matrices
5031: -  ctx - user context

5033:    Output Parameter:
5034: .  flag - structure of the matrix

5036:    Level: developer

5038: .keywords: SNES, nonlinear, compute, function

5040: .seealso: SNESSetFunction(), SNESGetFunction()
5041: @*/
5042: PetscErrorCode  SNESComputeJacobian_Matlab(SNES snes,Vec x,Mat *A,Mat *B,MatStructure *flag, void *ctx)
5043: {
5044:   PetscErrorCode    ierr;
5045:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5046:   int               nlhs  = 2,nrhs = 6;
5047:   mxArray           *plhs[2],*prhs[6];
5048:   long long int     lx = 0,lA = 0,ls = 0, lB = 0;


5054:   /* call Matlab function in ctx with arguments x and y */

5056:   PetscMemcpy(&ls,&snes,sizeof(snes));
5057:   PetscMemcpy(&lx,&x,sizeof(x));
5058:   PetscMemcpy(&lA,A,sizeof(x));
5059:   PetscMemcpy(&lB,B,sizeof(x));
5060:   prhs[0] = mxCreateDoubleScalar((double)ls);
5061:   prhs[1] = mxCreateDoubleScalar((double)lx);
5062:   prhs[2] = mxCreateDoubleScalar((double)lA);
5063:   prhs[3] = mxCreateDoubleScalar((double)lB);
5064:   prhs[4] = mxCreateString(sctx->funcname);
5065:   prhs[5] = sctx->ctx;
5066:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeJacobianInternal");
5067:   mxGetScalar(plhs[0]);
5068:   *flag   = (MatStructure) mxGetScalar(plhs[1]);
5069:   mxDestroyArray(prhs[0]);
5070:   mxDestroyArray(prhs[1]);
5071:   mxDestroyArray(prhs[2]);
5072:   mxDestroyArray(prhs[3]);
5073:   mxDestroyArray(prhs[4]);
5074:   mxDestroyArray(plhs[0]);
5075:   mxDestroyArray(plhs[1]);
5076:   return(0);
5077: }

5081: /*
5082:    SNESSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
5083:    vector for use by the SNES routines in solving systems of nonlinear
5084:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

5086:    Logically Collective on SNES

5088:    Input Parameters:
5089: +  snes - the SNES context
5090: .  A,B - Jacobian matrices
5091: .  J - function evaluation routine
5092: -  ctx - user context

5094:    Level: developer

5096:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5098: .keywords: SNES, nonlinear, set, function

5100: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction(), J
5101: */
5102: PetscErrorCode  SNESSetJacobianMatlab(SNES snes,Mat A,Mat B,const char *J,mxArray *ctx)
5103: {
5104:   PetscErrorCode    ierr;
5105:   SNESMatlabContext *sctx;

5108:   /* currently sctx is memory bleed */
5109:   PetscMalloc(sizeof(SNESMatlabContext),&sctx);
5110:   PetscStrallocpy(J,&sctx->funcname);
5111:   /*
5112:      This should work, but it doesn't
5113:   sctx->ctx = ctx;
5114:   mexMakeArrayPersistent(sctx->ctx);
5115:   */
5116:   sctx->ctx = mxDuplicateArray(ctx);
5117:   SNESSetJacobian(snes,A,B,SNESComputeJacobian_Matlab,sctx);
5118:   return(0);
5119: }

5123: /*
5124:    SNESMonitor_Matlab - Calls the function that has been set with SNESMonitorSetMatlab().

5126:    Collective on SNES

5128: .seealso: SNESSetFunction(), SNESGetFunction()
5129: @*/
5130: PetscErrorCode  SNESMonitor_Matlab(SNES snes,PetscInt it, PetscReal fnorm, void *ctx)
5131: {
5132:   PetscErrorCode    ierr;
5133:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5134:   int               nlhs  = 1,nrhs = 6;
5135:   mxArray           *plhs[1],*prhs[6];
5136:   long long int     lx = 0,ls = 0;
5137:   Vec               x  = snes->vec_sol;


5142:   PetscMemcpy(&ls,&snes,sizeof(snes));
5143:   PetscMemcpy(&lx,&x,sizeof(x));
5144:   prhs[0] = mxCreateDoubleScalar((double)ls);
5145:   prhs[1] = mxCreateDoubleScalar((double)it);
5146:   prhs[2] = mxCreateDoubleScalar((double)fnorm);
5147:   prhs[3] = mxCreateDoubleScalar((double)lx);
5148:   prhs[4] = mxCreateString(sctx->funcname);
5149:   prhs[5] = sctx->ctx;
5150:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESMonitorInternal");
5151:   mxGetScalar(plhs[0]);
5152:   mxDestroyArray(prhs[0]);
5153:   mxDestroyArray(prhs[1]);
5154:   mxDestroyArray(prhs[2]);
5155:   mxDestroyArray(prhs[3]);
5156:   mxDestroyArray(prhs[4]);
5157:   mxDestroyArray(plhs[0]);
5158:   return(0);
5159: }

5163: /*
5164:    SNESMonitorSetMatlab - Sets the monitor function from MATLAB

5166:    Level: developer

5168:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5170: .keywords: SNES, nonlinear, set, function

5172: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5173: */
5174: PetscErrorCode  SNESMonitorSetMatlab(SNES snes,const char *SNESMonitorFunction,mxArray *ctx)
5175: {
5176:   PetscErrorCode    ierr;
5177:   SNESMatlabContext *sctx;

5180:   /* currently sctx is memory bleed */
5181:   PetscMalloc(sizeof(SNESMatlabContext),&sctx);
5182:   PetscStrallocpy(SNESMonitorFunction,&sctx->funcname);
5183:   /*
5184:      This should work, but it doesn't
5185:   sctx->ctx = ctx;
5186:   mexMakeArrayPersistent(sctx->ctx);
5187:   */
5188:   sctx->ctx = mxDuplicateArray(ctx);
5189:   SNESMonitorSet(snes,SNESMonitor_Matlab,sctx,NULL);
5190:   return(0);
5191: }

5193: #endif