Actual source code: snes.c

petsc-main 2021-03-06
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  1: #include <petsc/private/snesimpl.h>
  2: #include <petscdmshell.h>
  3: #include <petscdraw.h>
  4: #include <petscds.h>
  5: #include <petscdmadaptor.h>
  6: #include <petscconvest.h>

  8: PetscBool         SNESRegisterAllCalled = PETSC_FALSE;
  9: PetscFunctionList SNESList              = NULL;

 11: /* Logging support */
 12: PetscClassId  SNES_CLASSID, DMSNES_CLASSID;
 13: PetscLogEvent SNES_Solve, SNES_Setup, SNES_FunctionEval, SNES_JacobianEval, SNES_NGSEval, SNES_NGSFuncEval, SNES_NPCSolve, SNES_ObjectiveEval;

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

 18:    Logically Collective on SNES

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

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

 27:    Level: intermediate

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

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

 44: /*@
 45:    SNESGetErrorIfNotConverged - Will SNESSolve() generate an error if the solver does not converge?

 47:    Not Collective

 49:    Input Parameter:
 50: .  snes - iterative context obtained from SNESCreate()

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

 55:    Level: intermediate

 57: .seealso:  SNESSetErrorIfNotConverged(), KSPGetErrorIfNotConverged(), KSPSetErrorIFNotConverged()
 58: @*/
 59: PetscErrorCode  SNESGetErrorIfNotConverged(SNES snes,PetscBool  *flag)
 60: {
 64:   *flag = snes->errorifnotconverged;
 65:   return(0);
 66: }

 68: /*@
 69:     SNESSetAlwaysComputesFinalResidual - does the SNES always compute the residual at the final solution?

 71:    Logically Collective on SNES

 73:     Input Parameters:
 74: +   snes - the shell SNES
 75: -   flg - is the residual computed?

 77:    Level: advanced

 79: .seealso: SNESGetAlwaysComputesFinalResidual()
 80: @*/
 81: PetscErrorCode  SNESSetAlwaysComputesFinalResidual(SNES snes, PetscBool flg)
 82: {
 85:   snes->alwayscomputesfinalresidual = flg;
 86:   return(0);
 87: }

 89: /*@
 90:     SNESGetAlwaysComputesFinalResidual - does the SNES always compute the residual at the final solution?

 92:    Logically Collective on SNES

 94:     Input Parameter:
 95: .   snes - the shell SNES

 97:     Output Parameter:
 98: .   flg - is the residual computed?

100:    Level: advanced

102: .seealso: SNESSetAlwaysComputesFinalResidual()
103: @*/
104: PetscErrorCode  SNESGetAlwaysComputesFinalResidual(SNES snes, PetscBool *flg)
105: {
108:   *flg = snes->alwayscomputesfinalresidual;
109:   return(0);
110: }

112: /*@
113:    SNESSetFunctionDomainError - tells SNES that the input vector to your SNESFunction is not
114:      in the functions domain. For example, negative pressure.

116:    Logically Collective on SNES

118:    Input Parameters:
119: .  snes - the SNES context

121:    Level: advanced

123: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction
124: @*/
125: PetscErrorCode  SNESSetFunctionDomainError(SNES snes)
126: {
129:   if (snes->errorifnotconverged) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"User code indicates input vector is not in the function domain");
130:   snes->domainerror = PETSC_TRUE;
131:   return(0);
132: }

134: /*@
135:    SNESSetJacobianDomainError - tells SNES that computeJacobian does not make sense any more. For example there is a negative element transformation.

137:    Logically Collective on SNES

139:    Input Parameters:
140: .  snes - the SNES context

142:    Level: advanced

144: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction(), SNESSetFunctionDomainError()
145: @*/
146: PetscErrorCode SNESSetJacobianDomainError(SNES snes)
147: {
150:   if (snes->errorifnotconverged) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"User code indicates computeJacobian does not make sense");
151:   snes->jacobiandomainerror = PETSC_TRUE;
152:   return(0);
153: }

155: /*@
156:    SNESSetCheckJacobianDomainError - if or not to check jacobian domain error after each Jacobian evaluation. By default, we check Jacobian domain error
157:    in the debug mode, and do not check it in the optimized mode.

159:    Logically Collective on SNES

161:    Input Parameters:
162: +  snes - the SNES context
163: -  flg  - indicates if or not to check jacobian domain error after each Jacobian evaluation

165:    Level: advanced

167: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction(), SNESSetFunctionDomainError(), SNESGetCheckJacobianDomainError()
168: @*/
169: PetscErrorCode SNESSetCheckJacobianDomainError(SNES snes, PetscBool flg)
170: {
173:   snes->checkjacdomainerror = flg;
174:   return(0);
175: }

177: /*@
178:    SNESGetCheckJacobianDomainError - Get an indicator whether or not we are checking Jacobian domain errors after each Jacobian evaluation.

180:    Logically Collective on SNES

182:    Input Parameters:
183: .  snes - the SNES context

185:    Output Parameters:
186: .  flg  - PETSC_FALSE indicates that we don't check jacobian domain errors after each Jacobian evaluation

188:    Level: advanced

190: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction(), SNESSetFunctionDomainError(), SNESSetCheckJacobianDomainError()
191: @*/
192: PetscErrorCode SNESGetCheckJacobianDomainError(SNES snes, PetscBool *flg)
193: {
197:   *flg = snes->checkjacdomainerror;
198:   return(0);
199: }

201: /*@
202:    SNESGetFunctionDomainError - Gets the status of the domain error after a call to SNESComputeFunction;

204:    Logically Collective on SNES

206:    Input Parameters:
207: .  snes - the SNES context

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

212:    Level: advanced

214: .seealso: SNESSetFunctionDomainError(), SNESComputeFunction()
215: @*/
216: PetscErrorCode  SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
217: {
221:   *domainerror = snes->domainerror;
222:   return(0);
223: }

225: /*@
226:    SNESGetJacobianDomainError - Gets the status of the Jacobian domain error after a call to SNESComputeJacobian;

228:    Logically Collective on SNES

230:    Input Parameters:
231: .  snes - the SNES context

233:    Output Parameters:
234: .  domainerror - Set to PETSC_TRUE if there's a jacobian domain error; PETSC_FALSE otherwise.

236:    Level: advanced

238: .seealso: SNESSetFunctionDomainError(), SNESComputeFunction(),SNESGetFunctionDomainError()
239: @*/
240: PetscErrorCode SNESGetJacobianDomainError(SNES snes, PetscBool *domainerror)
241: {
245:   *domainerror = snes->jacobiandomainerror;
246:   return(0);
247: }

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

252:   Collective on PetscViewer

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

259:    Level: intermediate

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

264:   Notes for advanced users:
265:   Most users should not need to know the details of the binary storage
266:   format, since SNESLoad() and TSView() completely hide these details.
267:   But for anyone who's interested, the standard binary matrix storage
268:   format is
269: .vb
270:      has not yet been determined
271: .ve

273: .seealso: PetscViewerBinaryOpen(), SNESView(), MatLoad(), VecLoad()
274: @*/
275: PetscErrorCode  SNESLoad(SNES snes, PetscViewer viewer)
276: {
278:   PetscBool      isbinary;
279:   PetscInt       classid;
280:   char           type[256];
281:   KSP            ksp;
282:   DM             dm;
283:   DMSNES         dmsnes;

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

291:   PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
292:   if (classid != SNES_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONG,"Not SNES next in file");
293:   PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
294:   SNESSetType(snes, type);
295:   if (snes->ops->load) {
296:     (*snes->ops->load)(snes,viewer);
297:   }
298:   SNESGetDM(snes,&dm);
299:   DMGetDMSNES(dm,&dmsnes);
300:   DMSNESLoad(dmsnes,viewer);
301:   SNESGetKSP(snes,&ksp);
302:   KSPLoad(ksp,viewer);
303:   return(0);
304: }

306: #include <petscdraw.h>
307: #if defined(PETSC_HAVE_SAWS)
308: #include <petscviewersaws.h>
309: #endif

311: /*@C
312:    SNESViewFromOptions - View from Options

314:    Collective on SNES

316:    Input Parameters:
317: +  A - the application ordering context
318: .  obj - Optional object
319: -  name - command line option

321:    Level: intermediate
322: .seealso:  SNES, SNESView, PetscObjectViewFromOptions(), SNESCreate()
323: @*/
324: PetscErrorCode  SNESViewFromOptions(SNES A,PetscObject obj,const char name[])
325: {

330:   PetscObjectViewFromOptions((PetscObject)A,obj,name);
331:   return(0);
332: }

334: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES,Vec,Mat,Mat,void*);

336: /*@C
337:    SNESView - Prints the SNES data structure.

339:    Collective on SNES

341:    Input Parameters:
342: +  SNES - the SNES context
343: -  viewer - visualization context

345:    Options Database Key:
346: .  -snes_view - Calls SNESView() at end of SNESSolve()

348:    Notes:
349:    The available visualization contexts include
350: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
351: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
352:          output where only the first processor opens
353:          the file.  All other processors send their
354:          data to the first processor to print.

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

359:   In the debugger you can do "call SNESView(snes,0)" to display the SNES solver. (The same holds for any PETSc object viewer).

361:    Level: beginner

363: .seealso: PetscViewerASCIIOpen()
364: @*/
365: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
366: {
367:   SNESKSPEW      *kctx;
369:   KSP            ksp;
370:   SNESLineSearch linesearch;
371:   PetscBool      iascii,isstring,isbinary,isdraw;
372:   DMSNES         dmsnes;
373: #if defined(PETSC_HAVE_SAWS)
374:   PetscBool      issaws;
375: #endif

379:   if (!viewer) {
380:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&viewer);
381:   }

385:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
386:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
387:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
388:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
389: #if defined(PETSC_HAVE_SAWS)
390:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
391: #endif
392:   if (iascii) {
393:     SNESNormSchedule normschedule;
394:     DM               dm;
395:     PetscErrorCode   (*cJ)(SNES,Vec,Mat,Mat,void*);
396:     void             *ctx;
397:     const char       *pre = "";

399:     PetscObjectPrintClassNamePrefixType((PetscObject)snes,viewer);
400:     if (!snes->setupcalled) {
401:       PetscViewerASCIIPrintf(viewer,"  SNES has not been set up so information may be incomplete\n");
402:     }
403:     if (snes->ops->view) {
404:       PetscViewerASCIIPushTab(viewer);
405:       (*snes->ops->view)(snes,viewer);
406:       PetscViewerASCIIPopTab(viewer);
407:     }
408:     PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
409:     PetscViewerASCIIPrintf(viewer,"  tolerances: relative=%g, absolute=%g, solution=%g\n",(double)snes->rtol,(double)snes->abstol,(double)snes->stol);
410:     if (snes->usesksp) {
411:       PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",snes->linear_its);
412:     }
413:     PetscViewerASCIIPrintf(viewer,"  total number of function evaluations=%D\n",snes->nfuncs);
414:     SNESGetNormSchedule(snes, &normschedule);
415:     if (normschedule > 0) {PetscViewerASCIIPrintf(viewer,"  norm schedule %s\n",SNESNormSchedules[normschedule]);}
416:     if (snes->gridsequence) {
417:       PetscViewerASCIIPrintf(viewer,"  total number of grid sequence refinements=%D\n",snes->gridsequence);
418:     }
419:     if (snes->ksp_ewconv) {
420:       kctx = (SNESKSPEW*)snes->kspconvctx;
421:       if (kctx) {
422:         PetscViewerASCIIPrintf(viewer,"  Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
423:         PetscViewerASCIIPrintf(viewer,"    rtol_0=%g, rtol_max=%g, threshold=%g\n",(double)kctx->rtol_0,(double)kctx->rtol_max,(double)kctx->threshold);
424:         PetscViewerASCIIPrintf(viewer,"    gamma=%g, alpha=%g, alpha2=%g\n",(double)kctx->gamma,(double)kctx->alpha,(double)kctx->alpha2);
425:       }
426:     }
427:     if (snes->lagpreconditioner == -1) {
428:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is never rebuilt\n");
429:     } else if (snes->lagpreconditioner > 1) {
430:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is rebuilt every %D new Jacobians\n",snes->lagpreconditioner);
431:     }
432:     if (snes->lagjacobian == -1) {
433:       PetscViewerASCIIPrintf(viewer,"  Jacobian is never rebuilt\n");
434:     } else if (snes->lagjacobian > 1) {
435:       PetscViewerASCIIPrintf(viewer,"  Jacobian is rebuilt every %D SNES iterations\n",snes->lagjacobian);
436:     }
437:     SNESGetDM(snes,&dm);
438:     DMSNESGetJacobian(dm,&cJ,&ctx);
439:     if (snes->mf_operator) {
440:       PetscViewerASCIIPrintf(viewer,"  Jacobian is applied matrix-free with differencing\n");
441:       pre  = "Preconditioning ";
442:     }
443:     if (cJ == SNESComputeJacobianDefault) {
444:       PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using finite differences one column at a time\n",pre);
445:     } else if (cJ == SNESComputeJacobianDefaultColor) {
446:       PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using finite differences with coloring\n",pre);
447:     /* it slightly breaks data encapsulation for access the DMDA information directly */
448:     } else if (cJ == SNESComputeJacobian_DMDA) {
449:       MatFDColoring fdcoloring;
450:       PetscObjectQuery((PetscObject)dm,"DMDASNES_FDCOLORING",(PetscObject*)&fdcoloring);
451:       if (fdcoloring) {
452:         PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using colored finite differences on a DMDA\n",pre);
453:       } else {
454:         PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using a DMDA local Jacobian\n",pre);
455:       }
456:     } else if (snes->mf) {
457:       PetscViewerASCIIPrintf(viewer,"  Jacobian is applied matrix-free with differencing, no explict Jacobian\n");
458:     }
459:   } else if (isstring) {
460:     const char *type;
461:     SNESGetType(snes,&type);
462:     PetscViewerStringSPrintf(viewer," SNESType: %-7.7s",type);
463:     if (snes->ops->view) {(*snes->ops->view)(snes,viewer);}
464:   } else if (isbinary) {
465:     PetscInt    classid = SNES_FILE_CLASSID;
466:     MPI_Comm    comm;
467:     PetscMPIInt rank;
468:     char        type[256];

470:     PetscObjectGetComm((PetscObject)snes,&comm);
471:     MPI_Comm_rank(comm,&rank);
472:     if (!rank) {
473:       PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT);
474:       PetscStrncpy(type,((PetscObject)snes)->type_name,sizeof(type));
475:       PetscViewerBinaryWrite(viewer,type,sizeof(type),PETSC_CHAR);
476:     }
477:     if (snes->ops->view) {
478:       (*snes->ops->view)(snes,viewer);
479:     }
480:   } else if (isdraw) {
481:     PetscDraw draw;
482:     char      str[36];
483:     PetscReal x,y,bottom,h;

485:     PetscViewerDrawGetDraw(viewer,0,&draw);
486:     PetscDrawGetCurrentPoint(draw,&x,&y);
487:     PetscStrncpy(str,"SNES: ",sizeof(str));
488:     PetscStrlcat(str,((PetscObject)snes)->type_name,sizeof(str));
489:     PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_BLUE,PETSC_DRAW_BLACK,str,NULL,&h);
490:     bottom = y - h;
491:     PetscDrawPushCurrentPoint(draw,x,bottom);
492:     if (snes->ops->view) {
493:       (*snes->ops->view)(snes,viewer);
494:     }
495: #if defined(PETSC_HAVE_SAWS)
496:   } else if (issaws) {
497:     PetscMPIInt rank;
498:     const char *name;

500:     PetscObjectGetName((PetscObject)snes,&name);
501:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
502:     if (!((PetscObject)snes)->amsmem && !rank) {
503:       char       dir[1024];

505:       PetscObjectViewSAWs((PetscObject)snes,viewer);
506:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
507:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
508:       if (!snes->conv_hist) {
509:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
510:       }
511:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
512:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
513:     }
514: #endif
515:   }
516:   if (snes->linesearch) {
517:     SNESGetLineSearch(snes, &linesearch);
518:     PetscViewerASCIIPushTab(viewer);
519:     SNESLineSearchView(linesearch, viewer);
520:     PetscViewerASCIIPopTab(viewer);
521:   }
522:   if (snes->npc && snes->usesnpc) {
523:     PetscViewerASCIIPushTab(viewer);
524:     SNESView(snes->npc, viewer);
525:     PetscViewerASCIIPopTab(viewer);
526:   }
527:   PetscViewerASCIIPushTab(viewer);
528:   DMGetDMSNES(snes->dm,&dmsnes);
529:   DMSNESView(dmsnes, viewer);
530:   PetscViewerASCIIPopTab(viewer);
531:   if (snes->usesksp) {
532:     SNESGetKSP(snes,&ksp);
533:     PetscViewerASCIIPushTab(viewer);
534:     KSPView(ksp,viewer);
535:     PetscViewerASCIIPopTab(viewer);
536:   }
537:   if (isdraw) {
538:     PetscDraw draw;
539:     PetscViewerDrawGetDraw(viewer,0,&draw);
540:     PetscDrawPopCurrentPoint(draw);
541:   }
542:   return(0);
543: }

545: /*
546:   We retain a list of functions that also take SNES command
547:   line options. These are called at the end SNESSetFromOptions()
548: */
549: #define MAXSETFROMOPTIONS 5
550: static PetscInt numberofsetfromoptions;
551: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

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

556:   Not Collective

558:   Input Parameter:
559: . snescheck - function that checks for options

561:   Level: developer

563: .seealso: SNESSetFromOptions()
564: @*/
565: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
566: {
568:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
569:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
570:   return(0);
571: }

573: PETSC_INTERN PetscErrorCode SNESDefaultMatrixFreeCreate2(SNES,Vec,Mat*);

575: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
576: {
577:   Mat            J;
579:   MatNullSpace   nullsp;


584:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
585:     Mat A = snes->jacobian, B = snes->jacobian_pre;
586:     MatCreateVecs(A ? A : B, NULL,&snes->vec_func);
587:   }

589:   if (version == 1) {
590:     MatCreateSNESMF(snes,&J);
591:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
592:     MatSetFromOptions(J);
593:   } else if (version == 2) {
594:     if (!snes->vec_func) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first");
595: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
596:     SNESDefaultMatrixFreeCreate2(snes,snes->vec_func,&J);
597: #else
598:     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP, "matrix-free operator routines (version 2)");
599: #endif
600:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator routines, only version 1 and 2");

602:   /* attach any user provided null space that was on Amat to the newly created matrix free matrix */
603:   if (snes->jacobian) {
604:     MatGetNullSpace(snes->jacobian,&nullsp);
605:     if (nullsp) {
606:       MatSetNullSpace(J,nullsp);
607:     }
608:   }

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

613:     /* This version replaces the user provided Jacobian matrix with a
614:        matrix-free version but still employs the user-provided preconditioner matrix. */
615:     SNESSetJacobian(snes,J,NULL,NULL,NULL);
616:   } else {
617:     /* This version replaces both the user-provided Jacobian and the user-
618:      provided preconditioner Jacobian with the default matrix free version. */
619:     if ((snes->npcside== PC_LEFT) && snes->npc) {
620:       if (!snes->jacobian){SNESSetJacobian(snes,J,NULL,NULL,NULL);}
621:     } else {
622:       KSP       ksp;
623:       PC        pc;
624:       PetscBool match;

626:       SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,NULL);
627:       /* Force no preconditioner */
628:       SNESGetKSP(snes,&ksp);
629:       KSPGetPC(ksp,&pc);
630:       PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&match);
631:       if (!match) {
632:         PetscInfo(snes,"Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n");
633:         PCSetType(pc,PCNONE);
634:       }
635:     }
636:   }
637:   MatDestroy(&J);
638:   return(0);
639: }

641: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
642: {
643:   SNES           snes = (SNES)ctx;
645:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

648:   if (PetscLogPrintInfo) {
649:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
650:     DMGetRefineLevel(dmfine,&finelevel);
651:     DMGetCoarsenLevel(dmfine,&fineclevel);
652:     DMGetRefineLevel(dmcoarse,&coarselevel);
653:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
654:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
655:   }
656:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
657:   else {
658:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
659:     Xfine = Xfine_named;
660:   }
661:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
662:   if (Inject) {
663:     MatRestrict(Inject,Xfine,Xcoarse);
664:   } else {
665:     MatRestrict(Restrict,Xfine,Xcoarse);
666:     VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
667:   }
668:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
669:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
670:   return(0);
671: }

673: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
674: {

678:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
679:   return(0);
680: }

682: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
683:  * safely call SNESGetDM() in their residual evaluation routine. */
684: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,void *ctx)
685: {
686:   SNES           snes = (SNES)ctx;
688:   Vec            X,Xnamed = NULL;
689:   DM             dmsave;
690:   void           *ctxsave;
691:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*) = NULL;

694:   dmsave = snes->dm;
695:   KSPGetDM(ksp,&snes->dm);
696:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
697:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
698:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
699:     X    = Xnamed;
700:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
701:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
702:     if (jac == SNESComputeJacobianDefaultColor) {
703:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,NULL);
704:     }
705:   }
706:   /* Make sure KSP DM has the Jacobian computation routine */
707:   {
708:     DMSNES sdm;

710:     DMGetDMSNES(snes->dm, &sdm);
711:     if (!sdm->ops->computejacobian) {
712:       DMCopyDMSNES(dmsave, snes->dm);
713:     }
714:   }
715:   /* Compute the operators */
716:   SNESComputeJacobian(snes,X,A,B);
717:   /* Put the previous context back */
718:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
719:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
720:   }

722:   if (Xnamed) {DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);}
723:   snes->dm = dmsave;
724:   return(0);
725: }

727: /*@
728:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

730:    Collective

732:    Input Arguments:
733: .  snes - snes to configure

735:    Level: developer

737: .seealso: SNESSetUp()
738: @*/
739: PetscErrorCode SNESSetUpMatrices(SNES snes)
740: {
742:   DM             dm;
743:   DMSNES         sdm;

746:   SNESGetDM(snes,&dm);
747:   DMGetDMSNES(dm,&sdm);
748:   if (!snes->jacobian && snes->mf) {
749:     Mat  J;
750:     void *functx;
751:     MatCreateSNESMF(snes,&J);
752:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
753:     MatSetFromOptions(J);
754:     SNESGetFunction(snes,NULL,NULL,&functx);
755:     SNESSetJacobian(snes,J,J,NULL,NULL);
756:     MatDestroy(&J);
757:   } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
758:     Mat J,B;
759:     MatCreateSNESMF(snes,&J);
760:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
761:     MatSetFromOptions(J);
762:     DMCreateMatrix(snes->dm,&B);
763:     /* sdm->computejacobian was already set to reach here */
764:     SNESSetJacobian(snes,J,B,NULL,NULL);
765:     MatDestroy(&J);
766:     MatDestroy(&B);
767:   } else if (!snes->jacobian_pre) {
768:     PetscDS   prob;
769:     Mat       J, B;
770:     PetscBool hasPrec   = PETSC_FALSE;

772:     J    = snes->jacobian;
773:     DMGetDS(dm, &prob);
774:     if (prob) {PetscDSHasJacobianPreconditioner(prob, &hasPrec);}
775:     if (J)            {PetscObjectReference((PetscObject) J);}
776:     else if (hasPrec) {DMCreateMatrix(snes->dm, &J);}
777:     DMCreateMatrix(snes->dm, &B);
778:     SNESSetJacobian(snes, J ? J : B, B, NULL, NULL);
779:     MatDestroy(&J);
780:     MatDestroy(&B);
781:   }
782:   {
783:     KSP ksp;
784:     SNESGetKSP(snes,&ksp);
785:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
786:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
787:   }
788:   return(0);
789: }

791: /*@C
792:    SNESMonitorSetFromOptions - Sets a monitor function and viewer appropriate for the type indicated by the user

794:    Collective on SNES

796:    Input Parameters:
797: +  snes - SNES object you wish to monitor
798: .  name - the monitor type one is seeking
799: .  help - message indicating what monitoring is done
800: .  manual - manual page for the monitor
801: .  monitor - the monitor function
802: -  monitorsetup - a function that is called once ONLY if the user selected this monitor that may set additional features of the SNES or PetscViewer objects

804:    Level: developer

806: .seealso: PetscOptionsGetViewer(), PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(),
807:           PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool()
808:           PetscOptionsInt(), PetscOptionsString(), PetscOptionsReal(), PetscOptionsBool(),
809:           PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(),
810:           PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(),
811:           PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(),
812:           PetscOptionsFList(), PetscOptionsEList()
813: @*/
814: PetscErrorCode  SNESMonitorSetFromOptions(SNES snes,const char name[],const char help[], const char manual[],PetscErrorCode (*monitor)(SNES,PetscInt,PetscReal,PetscViewerAndFormat*),PetscErrorCode (*monitorsetup)(SNES,PetscViewerAndFormat*))
815: {
816:   PetscErrorCode    ierr;
817:   PetscViewer       viewer;
818:   PetscViewerFormat format;
819:   PetscBool         flg;

822:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,name,&viewer,&format,&flg);
823:   if (flg) {
824:     PetscViewerAndFormat *vf;
825:     PetscViewerAndFormatCreate(viewer,format,&vf);
826:     PetscObjectDereference((PetscObject)viewer);
827:     if (monitorsetup) {
828:       (*monitorsetup)(snes,vf);
829:     }
830:     SNESMonitorSet(snes,(PetscErrorCode (*)(SNES,PetscInt,PetscReal,void*))monitor,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);
831:   }
832:   return(0);
833: }

835: /*@
836:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

838:    Collective on SNES

840:    Input Parameter:
841: .  snes - the SNES context

843:    Options Database Keys:
844: +  -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, SNESType for complete list
845: .  -snes_stol - convergence tolerance in terms of the norm
846:                 of the change in the solution between steps
847: .  -snes_atol <abstol> - absolute tolerance of residual norm
848: .  -snes_rtol <rtol> - relative decrease in tolerance norm from initial
849: .  -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
850: .  -snes_force_iteration <force> - force SNESSolve() to take at least one iteration
851: .  -snes_max_it <max_it> - maximum number of iterations
852: .  -snes_max_funcs <max_funcs> - maximum number of function evaluations
853: .  -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
854: .  -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
855: .  -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
856: .  -snes_lag_preconditioner_persists <true,false> - retains the -snes_lag_preconditioner information across multiple SNESSolve()
857: .  -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
858: .  -snes_lag_jacobian_persists <true,false> - retains the -snes_lag_jacobian information across multiple SNESSolve()
859: .  -snes_trtol <trtol> - trust region tolerance
860: .  -snes_no_convergence_test - skip convergence test in nonlinear
861:                                solver; hence iterations will continue until max_it
862:                                or some other criterion is reached. Saves expense
863:                                of convergence test
864: .  -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
865: .  -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
866: .  -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
867: .  -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
868: .  -snes_monitor_lg_residualnorm - plots residual norm at each iteration
869: .  -snes_monitor_lg_range - plots residual norm at each iteration
870: .  -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
871: .  -snes_fd_color - use finite differences with coloring to compute Jacobian
872: .  -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
873: .  -snes_converged_reason - print the reason for convergence/divergence after each solve
874: .  -npc_snes_type <type> - the SNES type to use as a nonlinear preconditioner
875: .   -snes_test_jacobian <optional threshold> - compare the user provided Jacobian with one computed via finite differences to check for errors.  If a threshold is given, display only those entries whose difference is greater than the threshold.
876: -   -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference between them to help users detect the location of errors in the user provided Jacobian.

878:     Options Database for Eisenstat-Walker method:
879: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
880: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
881: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
882: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
883: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
884: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
885: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
886: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

888:    Notes:
889:    To see all options, run your program with the -help option or consult the users manual

891:    Notes:
892:       SNES supports three approaches for computing (approximate) Jacobians: user provided via SNESSetJacobian(), matrix free, and computing explictly with
893:       finite differences and coloring using MatFDColoring. It is also possible to use automatic differentiation and the MatFDColoring object.

895:    Level: beginner

897: .seealso: SNESSetOptionsPrefix(), SNESResetFromOptions(), SNES, SNESCreate()
898: @*/
899: PetscErrorCode  SNESSetFromOptions(SNES snes)
900: {
901:   PetscBool      flg,pcset,persist,set;
902:   PetscInt       i,indx,lag,grids;
903:   const char     *deft        = SNESNEWTONLS;
904:   const char     *convtests[] = {"default","skip","correct_pressure"};
905:   SNESKSPEW      *kctx        = NULL;
906:   char           type[256], monfilename[PETSC_MAX_PATH_LEN];
908:   PCSide         pcside;
909:   const char     *optionsprefix;

913:   SNESRegisterAll();
914:   PetscObjectOptionsBegin((PetscObject)snes);
915:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
916:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
917:   if (flg) {
918:     SNESSetType(snes,type);
919:   } else if (!((PetscObject)snes)->type_name) {
920:     SNESSetType(snes,deft);
921:   }
922:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,NULL);
923:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,NULL);

925:   PetscOptionsReal("-snes_rtol","Stop if decrease in function norm less than","SNESSetTolerances",snes->rtol,&snes->rtol,NULL);
926:   PetscOptionsReal("-snes_divergence_tolerance","Stop if residual norm increases by this factor","SNESSetDivergenceTolerance",snes->divtol,&snes->divtol,NULL);
927:   PetscOptionsInt("-snes_max_it","Maximum iterations","SNESSetTolerances",snes->max_its,&snes->max_its,NULL);
928:   PetscOptionsInt("-snes_max_funcs","Maximum function evaluations","SNESSetTolerances",snes->max_funcs,&snes->max_funcs,NULL);
929:   PetscOptionsInt("-snes_max_fail","Maximum nonlinear step failures","SNESSetMaxNonlinearStepFailures",snes->maxFailures,&snes->maxFailures,NULL);
930:   PetscOptionsInt("-snes_max_linear_solve_fail","Maximum failures in linear solves allowed","SNESSetMaxLinearSolveFailures",snes->maxLinearSolveFailures,&snes->maxLinearSolveFailures,NULL);
931:   PetscOptionsBool("-snes_error_if_not_converged","Generate error if solver does not converge","SNESSetErrorIfNotConverged",snes->errorifnotconverged,&snes->errorifnotconverged,NULL);
932:   PetscOptionsBool("-snes_force_iteration","Force SNESSolve() to take at least one iteration","SNESSetForceIteration",snes->forceiteration,&snes->forceiteration,NULL);
933:   PetscOptionsBool("-snes_check_jacobian_domain_error","Check Jacobian domain error after Jacobian evaluation","SNESCheckJacobianDomainError",snes->checkjacdomainerror,&snes->checkjacdomainerror,NULL);

935:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
936:   if (flg) {
937:     if (lag == -1) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Cannot set the lag to -1 from the command line since the preconditioner must be built as least once, perhaps you mean -2");
938:     SNESSetLagPreconditioner(snes,lag);
939:   }
940:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple SNES solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
941:   if (flg) {
942:     SNESSetLagPreconditionerPersists(snes,persist);
943:   }
944:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
945:   if (flg) {
946:     if (lag == -1) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Cannot set the lag to -1 from the command line since the Jacobian must be built as least once, perhaps you mean -2");
947:     SNESSetLagJacobian(snes,lag);
948:   }
949:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple SNES solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
950:   if (flg) {
951:     SNESSetLagJacobianPersists(snes,persist);
952:   }

954:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
955:   if (flg) {
956:     SNESSetGridSequence(snes,grids);
957:   }

959:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,sizeof(convtests)/sizeof(char*),"default",&indx,&flg);
960:   if (flg) {
961:     switch (indx) {
962:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
963:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL); break;
964:     case 2: SNESSetConvergenceTest(snes,SNESConvergedCorrectPressure,NULL,NULL); break;
965:     }
966:   }

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

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

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

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

978:   PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,NULL);
979:   PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,NULL);
980:   PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,NULL);
981:   PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,NULL);
982:   PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,NULL);
983:   PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,NULL);
984:   PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",kctx->threshold,&kctx->threshold,NULL);

986:   flg  = PETSC_FALSE;
987:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,&set);
988:   if (set && flg) {SNESMonitorCancel(snes);}

990:   SNESMonitorSetFromOptions(snes,"-snes_monitor","Monitor norm of function","SNESMonitorDefault",SNESMonitorDefault,NULL);
991:   SNESMonitorSetFromOptions(snes,"-snes_monitor_short","Monitor norm of function with fewer digits","SNESMonitorDefaultShort",SNESMonitorDefaultShort,NULL);
992:   SNESMonitorSetFromOptions(snes,"-snes_monitor_range","Monitor range of elements of function","SNESMonitorRange",SNESMonitorRange,NULL);

994:   SNESMonitorSetFromOptions(snes,"-snes_monitor_ratio","Monitor ratios of the norm of function for consecutive steps","SNESMonitorRatio",SNESMonitorRatio,SNESMonitorRatioSetUp);
995:   SNESMonitorSetFromOptions(snes,"-snes_monitor_field","Monitor norm of function (split into fields)","SNESMonitorDefaultField",SNESMonitorDefaultField,NULL);
996:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution","View solution at each iteration","SNESMonitorSolution",SNESMonitorSolution,NULL);
997:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution_update","View correction at each iteration","SNESMonitorSolutionUpdate",SNESMonitorSolutionUpdate,NULL);
998:   SNESMonitorSetFromOptions(snes,"-snes_monitor_residual","View residual at each iteration","SNESMonitorResidual",SNESMonitorResidual,NULL);
999:   SNESMonitorSetFromOptions(snes,"-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",SNESMonitorJacUpdateSpectrum,NULL);
1000:   SNESMonitorSetFromOptions(snes,"-snes_monitor_fields","Monitor norm of function per field","SNESMonitorSet",SNESMonitorFields,NULL);

1002:   PetscOptionsString("-snes_monitor_python","Use Python function","SNESMonitorSet",NULL,monfilename,sizeof(monfilename),&flg);
1003:   if (flg) {PetscPythonMonitorSet((PetscObject)snes,monfilename);}

1005:   flg  = PETSC_FALSE;
1006:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
1007:   if (flg) {
1008:     PetscViewer ctx;

1010:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
1011:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
1012:   }

1014:   flg  = PETSC_FALSE;
1015:   PetscOptionsBool("-snes_converged_reason_view_cancel","Remove all converged reason viewers","SNESConvergedReasonViewCancel",flg,&flg,&set);
1016:   if (set && flg) {SNESConvergedReasonViewCancel(snes);}

1018:   flg  = PETSC_FALSE;
1019:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
1020:   if (flg) {
1021:     void    *functx;
1022:     DM      dm;
1023:     DMSNES  sdm;
1024:     SNESGetDM(snes,&dm);
1025:     DMGetDMSNES(dm,&sdm);
1026:     sdm->jacobianctx = NULL;
1027:     SNESGetFunction(snes,NULL,NULL,&functx);
1028:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
1029:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
1030:   }

1032:   flg  = PETSC_FALSE;
1033:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
1034:   if (flg) {
1035:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
1036:   }

1038:   flg  = PETSC_FALSE;
1039:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
1040:   if (flg) {
1041:     DM             dm;
1042:     DMSNES         sdm;
1043:     SNESGetDM(snes,&dm);
1044:     DMGetDMSNES(dm,&sdm);
1045:     sdm->jacobianctx = NULL;
1046:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,NULL);
1047:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
1048:   }

1050:   flg  = PETSC_FALSE;
1051:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf_operator,&flg);
1052:   if (flg && snes->mf_operator) {
1053:     snes->mf_operator = PETSC_TRUE;
1054:     snes->mf          = PETSC_TRUE;
1055:   }
1056:   flg  = PETSC_FALSE;
1057:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf,&flg);
1058:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1059:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,NULL);

1061:   flg  = PETSC_FALSE;
1062:   SNESGetNPCSide(snes,&pcside);
1063:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetNPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
1064:   if (flg) {SNESSetNPCSide(snes,pcside);}

1066: #if defined(PETSC_HAVE_SAWS)
1067:   /*
1068:     Publish convergence information using SAWs
1069:   */
1070:   flg  = PETSC_FALSE;
1071:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
1072:   if (flg) {
1073:     void *ctx;
1074:     SNESMonitorSAWsCreate(snes,&ctx);
1075:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
1076:   }
1077: #endif
1078: #if defined(PETSC_HAVE_SAWS)
1079:   {
1080:   PetscBool set;
1081:   flg  = PETSC_FALSE;
1082:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
1083:   if (set) {
1084:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
1085:   }
1086:   }
1087: #endif

1089:   for (i = 0; i < numberofsetfromoptions; i++) {
1090:     (*othersetfromoptions[i])(snes);
1091:   }

1093:   if (snes->ops->setfromoptions) {
1094:     (*snes->ops->setfromoptions)(PetscOptionsObject,snes);
1095:   }

1097:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
1098:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)snes);
1099:   PetscOptionsEnd();

1101:   if (snes->linesearch) {
1102:     SNESGetLineSearch(snes, &snes->linesearch);
1103:     SNESLineSearchSetFromOptions(snes->linesearch);
1104:   }

1106:   if (snes->usesksp) {
1107:     if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
1108:     KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
1109:     KSPSetFromOptions(snes->ksp);
1110:   }

1112:   /* if user has set the SNES NPC type via options database, create it. */
1113:   SNESGetOptionsPrefix(snes, &optionsprefix);
1114:   PetscOptionsHasName(((PetscObject)snes)->options,optionsprefix, "-npc_snes_type", &pcset);
1115:   if (pcset && (!snes->npc)) {
1116:     SNESGetNPC(snes, &snes->npc);
1117:   }
1118:   if (snes->npc) {
1119:     SNESSetFromOptions(snes->npc);
1120:   }
1121:   snes->setfromoptionscalled++;
1122:   return(0);
1123: }

1125: /*@
1126:    SNESResetFromOptions - Sets various SNES and KSP parameters from user options ONLY if the SNES was previously set from options

1128:    Collective on SNES

1130:    Input Parameter:
1131: .  snes - the SNES context

1133:    Level: beginner

1135: .seealso: SNESSetFromOptions(), SNESSetOptionsPrefix()
1136: @*/
1137: PetscErrorCode SNESResetFromOptions(SNES snes)
1138: {

1142:   if (snes->setfromoptionscalled) {SNESSetFromOptions(snes);}
1143:   return(0);
1144: }

1146: /*@C
1147:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1148:    the nonlinear solvers.

1150:    Logically Collective on SNES

1152:    Input Parameters:
1153: +  snes - the SNES context
1154: .  compute - function to compute the context
1155: -  destroy - function to destroy the context

1157:    Level: intermediate

1159:    Notes:
1160:    This function is currently not available from Fortran.

1162: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
1163: @*/
1164: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
1165: {
1168:   snes->ops->usercompute = compute;
1169:   snes->ops->userdestroy = destroy;
1170:   return(0);
1171: }

1173: /*@
1174:    SNESSetApplicationContext - Sets the optional user-defined context for
1175:    the nonlinear solvers.

1177:    Logically Collective on SNES

1179:    Input Parameters:
1180: +  snes - the SNES context
1181: -  usrP - optional user context

1183:    Level: intermediate

1185:    Fortran Notes:
1186:     To use this from Fortran you must write a Fortran interface definition for this
1187:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1189: .seealso: SNESGetApplicationContext()
1190: @*/
1191: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
1192: {
1194:   KSP            ksp;

1198:   SNESGetKSP(snes,&ksp);
1199:   KSPSetApplicationContext(ksp,usrP);
1200:   snes->user = usrP;
1201:   return(0);
1202: }

1204: /*@
1205:    SNESGetApplicationContext - Gets the user-defined context for the
1206:    nonlinear solvers.

1208:    Not Collective

1210:    Input Parameter:
1211: .  snes - SNES context

1213:    Output Parameter:
1214: .  usrP - user context

1216:    Fortran Notes:
1217:     To use this from Fortran you must write a Fortran interface definition for this
1218:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1220:    Level: intermediate

1222: .seealso: SNESSetApplicationContext()
1223: @*/
1224: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
1225: {
1228:   *(void**)usrP = snes->user;
1229:   return(0);
1230: }

1232: /*@
1233:    SNESSetUseMatrixFree - indicates that SNES should use matrix free finite difference matrix vector products internally to apply the Jacobian.

1235:    Collective on SNES

1237:    Input Parameters:
1238: +  snes - SNES context
1239: .  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used
1240: -  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored

1242:    Options Database:
1243: + -snes_mf - use matrix free for both the mat and pmat operator
1244: . -snes_mf_operator - use matrix free only for the mat operator
1245: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1246: - -snes_fd - compute the Jacobian via finite differences (slow)

1248:    Level: intermediate

1250:    Notes:
1251:       SNES supports three approaches for computing (approximate) Jacobians: user provided via SNESSetJacobian(), matrix free, and computing explictly with
1252:       finite differences and coloring using MatFDColoring. It is also possible to use automatic differentiation and the MatFDColoring object.

1254: .seealso:   SNESGetUseMatrixFree(), MatCreateSNESMF(), SNESComputeJacobianDefaultColor()
1255: @*/
1256: PetscErrorCode  SNESSetUseMatrixFree(SNES snes,PetscBool mf_operator,PetscBool mf)
1257: {
1262:   snes->mf          = mf_operator ? PETSC_TRUE : mf;
1263:   snes->mf_operator = mf_operator;
1264:   return(0);
1265: }

1267: /*@
1268:    SNESGetUseMatrixFree - indicates if the SNES uses matrix free finite difference matrix vector products to apply the Jacobian.

1270:    Collective on SNES

1272:    Input Parameter:
1273: .  snes - SNES context

1275:    Output Parameters:
1276: +  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used
1277: -  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored

1279:    Options Database:
1280: + -snes_mf - use matrix free for both the mat and pmat operator
1281: - -snes_mf_operator - use matrix free only for the mat operator

1283:    Level: intermediate

1285: .seealso:   SNESSetUseMatrixFree(), MatCreateSNESMF()
1286: @*/
1287: PetscErrorCode  SNESGetUseMatrixFree(SNES snes,PetscBool *mf_operator,PetscBool *mf)
1288: {
1291:   if (mf)          *mf          = snes->mf;
1292:   if (mf_operator) *mf_operator = snes->mf_operator;
1293:   return(0);
1294: }

1296: /*@
1297:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1298:    at this time.

1300:    Not Collective

1302:    Input Parameter:
1303: .  snes - SNES context

1305:    Output Parameter:
1306: .  iter - iteration number

1308:    Notes:
1309:    For example, during the computation of iteration 2 this would return 1.

1311:    This is useful for using lagged Jacobians (where one does not recompute the
1312:    Jacobian at each SNES iteration). For example, the code
1313: .vb
1314:       SNESGetIterationNumber(snes,&it);
1315:       if (!(it % 2)) {
1316:         [compute Jacobian here]
1317:       }
1318: .ve
1319:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1320:    recomputed every second SNES iteration.

1322:    After the SNES solve is complete this will return the number of nonlinear iterations used.

1324:    Level: intermediate

1326: .seealso:   SNESGetLinearSolveIterations()
1327: @*/
1328: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1329: {
1333:   *iter = snes->iter;
1334:   return(0);
1335: }

1337: /*@
1338:    SNESSetIterationNumber - Sets the current iteration number.

1340:    Not Collective

1342:    Input Parameter:
1343: +  snes - SNES context
1344: -  iter - iteration number

1346:    Level: developer

1348: .seealso:   SNESGetLinearSolveIterations()
1349: @*/
1350: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1351: {

1356:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1357:   snes->iter = iter;
1358:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1359:   return(0);
1360: }

1362: /*@
1363:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1364:    attempted by the nonlinear solver.

1366:    Not Collective

1368:    Input Parameter:
1369: .  snes - SNES context

1371:    Output Parameter:
1372: .  nfails - number of unsuccessful steps attempted

1374:    Notes:
1375:    This counter is reset to zero for each successive call to SNESSolve().

1377:    Level: intermediate

1379: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1380:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1381: @*/
1382: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1383: {
1387:   *nfails = snes->numFailures;
1388:   return(0);
1389: }

1391: /*@
1392:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1393:    attempted by the nonlinear solver before it gives up.

1395:    Not Collective

1397:    Input Parameters:
1398: +  snes     - SNES context
1399: -  maxFails - maximum of unsuccessful steps

1401:    Level: intermediate

1403: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1404:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1405: @*/
1406: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1407: {
1410:   snes->maxFailures = maxFails;
1411:   return(0);
1412: }

1414: /*@
1415:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1416:    attempted by the nonlinear solver before it gives up.

1418:    Not Collective

1420:    Input Parameter:
1421: .  snes     - SNES context

1423:    Output Parameter:
1424: .  maxFails - maximum of unsuccessful steps

1426:    Level: intermediate

1428: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1429:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1431: @*/
1432: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1433: {
1437:   *maxFails = snes->maxFailures;
1438:   return(0);
1439: }

1441: /*@
1442:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1443:      done by SNES.

1445:    Not Collective

1447:    Input Parameter:
1448: .  snes     - SNES context

1450:    Output Parameter:
1451: .  nfuncs - number of evaluations

1453:    Level: intermediate

1455:    Notes:
1456:     Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1458: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1459: @*/
1460: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1461: {
1465:   *nfuncs = snes->nfuncs;
1466:   return(0);
1467: }

1469: /*@
1470:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1471:    linear solvers.

1473:    Not Collective

1475:    Input Parameter:
1476: .  snes - SNES context

1478:    Output Parameter:
1479: .  nfails - number of failed solves

1481:    Level: intermediate

1483:    Options Database Keys:
1484: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1486:    Notes:
1487:    This counter is reset to zero for each successive call to SNESSolve().

1489: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1490: @*/
1491: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1492: {
1496:   *nfails = snes->numLinearSolveFailures;
1497:   return(0);
1498: }

1500: /*@
1501:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1502:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1504:    Logically Collective on SNES

1506:    Input Parameters:
1507: +  snes     - SNES context
1508: -  maxFails - maximum allowed linear solve failures

1510:    Level: intermediate

1512:    Options Database Keys:
1513: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1515:    Notes:
1516:     By default this is 0; that is SNES returns on the first failed linear solve

1518: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations()
1519: @*/
1520: PetscErrorCode  SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1521: {
1525:   snes->maxLinearSolveFailures = maxFails;
1526:   return(0);
1527: }

1529: /*@
1530:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1531:      are allowed before SNES terminates

1533:    Not Collective

1535:    Input Parameter:
1536: .  snes     - SNES context

1538:    Output Parameter:
1539: .  maxFails - maximum of unsuccessful solves allowed

1541:    Level: intermediate

1543:    Notes:
1544:     By default this is 1; that is SNES returns on the first failed linear solve

1546: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1547: @*/
1548: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1549: {
1553:   *maxFails = snes->maxLinearSolveFailures;
1554:   return(0);
1555: }

1557: /*@
1558:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1559:    used by the nonlinear solver.

1561:    Not Collective

1563:    Input Parameter:
1564: .  snes - SNES context

1566:    Output Parameter:
1567: .  lits - number of linear iterations

1569:    Notes:
1570:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1572:    If the linear solver fails inside the SNESSolve() the iterations for that call to the linear solver are not included. If you wish to count them
1573:    then call KSPGetIterationNumber() after the failed solve.

1575:    Level: intermediate

1577: .seealso:  SNESGetIterationNumber(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1578: @*/
1579: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1580: {
1584:   *lits = snes->linear_its;
1585:   return(0);
1586: }

1588: /*@
1589:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1590:    are reset every time SNESSolve() is called.

1592:    Logically Collective on SNES

1594:    Input Parameter:
1595: +  snes - SNES context
1596: -  reset - whether to reset the counters or not

1598:    Notes:
1599:    This defaults to PETSC_TRUE

1601:    Level: developer

1603: .seealso:  SNESGetNumberFunctionEvals(), SNESGetLinearSolveIterations(), SNESGetNPC()
1604: @*/
1605: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1606: {
1610:   snes->counters_reset = reset;
1611:   return(0);
1612: }


1615: /*@
1616:    SNESSetKSP - Sets a KSP context for the SNES object to use

1618:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1620:    Input Parameters:
1621: +  snes - the SNES context
1622: -  ksp - the KSP context

1624:    Notes:
1625:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1626:    so this routine is rarely needed.

1628:    The KSP object that is already in the SNES object has its reference count
1629:    decreased by one.

1631:    Level: developer

1633: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1634: @*/
1635: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1636: {

1643:   PetscObjectReference((PetscObject)ksp);
1644:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1645:   snes->ksp = ksp;
1646:   return(0);
1647: }

1649: /* -----------------------------------------------------------*/
1650: /*@
1651:    SNESCreate - Creates a nonlinear solver context.

1653:    Collective

1655:    Input Parameters:
1656: .  comm - MPI communicator

1658:    Output Parameter:
1659: .  outsnes - the new SNES context

1661:    Options Database Keys:
1662: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1663:                and no preconditioning matrix
1664: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1665:                products, and a user-provided preconditioning matrix
1666:                as set by SNESSetJacobian()
1667: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1669:    Level: beginner

1671:    Developer Notes:
1672:     SNES always creates a KSP object even though many SNES methods do not use it. This is
1673:                     unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1674:                     particular method does use KSP and regulates if the information about the KSP is printed
1675:                     in SNESView(). TSSetFromOptions() does call SNESSetFromOptions() which can lead to users being confused
1676:                     by help messages about meaningless SNES options.

1678:                     SNES always creates the snes->kspconvctx even though it is used by only one type. This should
1679:                     be fixed.

1681: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner(), SNESSetLagJacobian()

1683: @*/
1684: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1685: {
1687:   SNES           snes;
1688:   SNESKSPEW      *kctx;

1692:   *outsnes = NULL;
1693:   SNESInitializePackage();

1695:   PetscHeaderCreate(snes,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1697:   snes->ops->converged    = SNESConvergedDefault;
1698:   snes->usesksp           = PETSC_TRUE;
1699:   snes->tolerancesset     = PETSC_FALSE;
1700:   snes->max_its           = 50;
1701:   snes->max_funcs         = 10000;
1702:   snes->norm              = 0.0;
1703:   snes->xnorm             = 0.0;
1704:   snes->ynorm             = 0.0;
1705:   snes->normschedule      = SNES_NORM_ALWAYS;
1706:   snes->functype          = SNES_FUNCTION_DEFAULT;
1707: #if defined(PETSC_USE_REAL_SINGLE)
1708:   snes->rtol              = 1.e-5;
1709: #else
1710:   snes->rtol              = 1.e-8;
1711: #endif
1712:   snes->ttol              = 0.0;
1713: #if defined(PETSC_USE_REAL_SINGLE)
1714:   snes->abstol            = 1.e-25;
1715: #else
1716:   snes->abstol            = 1.e-50;
1717: #endif
1718: #if defined(PETSC_USE_REAL_SINGLE)
1719:   snes->stol              = 1.e-5;
1720: #else
1721:   snes->stol              = 1.e-8;
1722: #endif
1723: #if defined(PETSC_USE_REAL_SINGLE)
1724:   snes->deltatol          = 1.e-6;
1725: #else
1726:   snes->deltatol          = 1.e-12;
1727: #endif
1728:   snes->divtol            = 1.e4;
1729:   snes->rnorm0            = 0;
1730:   snes->nfuncs            = 0;
1731:   snes->numFailures       = 0;
1732:   snes->maxFailures       = 1;
1733:   snes->linear_its        = 0;
1734:   snes->lagjacobian       = 1;
1735:   snes->jac_iter          = 0;
1736:   snes->lagjac_persist    = PETSC_FALSE;
1737:   snes->lagpreconditioner = 1;
1738:   snes->pre_iter          = 0;
1739:   snes->lagpre_persist    = PETSC_FALSE;
1740:   snes->numbermonitors    = 0;
1741:   snes->numberreasonviews = 0;
1742:   snes->data              = NULL;
1743:   snes->setupcalled       = PETSC_FALSE;
1744:   snes->ksp_ewconv        = PETSC_FALSE;
1745:   snes->nwork             = 0;
1746:   snes->work              = NULL;
1747:   snes->nvwork            = 0;
1748:   snes->vwork             = NULL;
1749:   snes->conv_hist_len     = 0;
1750:   snes->conv_hist_max     = 0;
1751:   snes->conv_hist         = NULL;
1752:   snes->conv_hist_its     = NULL;
1753:   snes->conv_hist_reset   = PETSC_TRUE;
1754:   snes->counters_reset    = PETSC_TRUE;
1755:   snes->vec_func_init_set = PETSC_FALSE;
1756:   snes->reason            = SNES_CONVERGED_ITERATING;
1757:   snes->npcside           = PC_RIGHT;
1758:   snes->setfromoptionscalled = 0;

1760:   snes->mf          = PETSC_FALSE;
1761:   snes->mf_operator = PETSC_FALSE;
1762:   snes->mf_version  = 1;

1764:   snes->numLinearSolveFailures = 0;
1765:   snes->maxLinearSolveFailures = 1;

1767:   snes->vizerotolerance = 1.e-8;
1768:   snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;

1770:   /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1771:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

1773:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1774:   PetscNewLog(snes,&kctx);

1776:   snes->kspconvctx  = (void*)kctx;
1777:   kctx->version     = 2;
1778:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1779:                              this was too large for some test cases */
1780:   kctx->rtol_last   = 0.0;
1781:   kctx->rtol_max    = .9;
1782:   kctx->gamma       = 1.0;
1783:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1784:   kctx->alpha2      = kctx->alpha;
1785:   kctx->threshold   = .1;
1786:   kctx->lresid_last = 0.0;
1787:   kctx->norm_last   = 0.0;

1789:   *outsnes = snes;
1790:   return(0);
1791: }

1793: /*MC
1794:     SNESFunction - Functional form used to convey the nonlinear function to be solved by SNES

1796:      Synopsis:
1797:      #include "petscsnes.h"
1798:      PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1800:      Collective on snes

1802:      Input Parameters:
1803: +     snes - the SNES context
1804: .     x    - state at which to evaluate residual
1805: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1807:      Output Parameter:
1808: .     f  - vector to put residual (function value)

1810:    Level: intermediate

1812: .seealso:   SNESSetFunction(), SNESGetFunction()
1813: M*/

1815: /*@C
1816:    SNESSetFunction - Sets the function evaluation routine and function
1817:    vector for use by the SNES routines in solving systems of nonlinear
1818:    equations.

1820:    Logically Collective on SNES

1822:    Input Parameters:
1823: +  snes - the SNES context
1824: .  r - vector to store function value
1825: .  f - function evaluation routine; see SNESFunction for calling sequence details
1826: -  ctx - [optional] user-defined context for private data for the
1827:          function evaluation routine (may be NULL)

1829:    Notes:
1830:    The Newton-like methods typically solve linear systems of the form
1831: $      f'(x) x = -f(x),
1832:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1834:    Level: beginner

1836: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1837: @*/
1838: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1839: {
1841:   DM             dm;

1845:   if (r) {
1848:     PetscObjectReference((PetscObject)r);
1849:     VecDestroy(&snes->vec_func);

1851:     snes->vec_func = r;
1852:   }
1853:   SNESGetDM(snes,&dm);
1854:   DMSNESSetFunction(dm,f,ctx);
1855:   return(0);
1856: }


1859: /*@C
1860:    SNESSetInitialFunction - Sets the function vector to be used as the
1861:    function norm at the initialization of the method.  In some
1862:    instances, the user has precomputed the function before calling
1863:    SNESSolve.  This function allows one to avoid a redundant call
1864:    to SNESComputeFunction in that case.

1866:    Logically Collective on SNES

1868:    Input Parameters:
1869: +  snes - the SNES context
1870: -  f - vector to store function value

1872:    Notes:
1873:    This should not be modified during the solution procedure.

1875:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1877:    Level: developer

1879: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1880: @*/
1881: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1882: {
1884:   Vec            vec_func;

1890:   if (snes->npcside== PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1891:     snes->vec_func_init_set = PETSC_FALSE;
1892:     return(0);
1893:   }
1894:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1895:   VecCopy(f, vec_func);

1897:   snes->vec_func_init_set = PETSC_TRUE;
1898:   return(0);
1899: }

1901: /*@
1902:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1903:    of the SNES method.

1905:    Logically Collective on SNES

1907:    Input Parameters:
1908: +  snes - the SNES context
1909: -  normschedule - the frequency of norm computation

1911:    Options Database Key:
1912: .  -snes_norm_schedule <none, always, initialonly, finalonly, initalfinalonly>

1914:    Notes:
1915:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1916:    of the nonlinear function and the taking of its norm at every iteration to
1917:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1918:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1919:    may either be monitored for convergence or not.  As these are often used as nonlinear
1920:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1921:    their solution.

1923:    Level: developer

1925: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1926: @*/
1927: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1928: {
1931:   snes->normschedule = normschedule;
1932:   return(0);
1933: }


1936: /*@
1937:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1938:    of the SNES method.

1940:    Logically Collective on SNES

1942:    Input Parameters:
1943: +  snes - the SNES context
1944: -  normschedule - the type of the norm used

1946:    Level: advanced

1948: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1949: @*/
1950: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1951: {
1954:   *normschedule = snes->normschedule;
1955:   return(0);
1956: }


1959: /*@
1960:   SNESSetFunctionNorm - Sets the last computed residual norm.

1962:   Logically Collective on SNES

1964:   Input Parameters:
1965: + snes - the SNES context

1967: - normschedule - the frequency of norm computation

1969:   Level: developer

1971: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1972: @*/
1973: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
1974: {
1977:   snes->norm = norm;
1978:   return(0);
1979: }

1981: /*@
1982:   SNESGetFunctionNorm - Gets the last computed norm of the residual

1984:   Not Collective

1986:   Input Parameter:
1987: . snes - the SNES context

1989:   Output Parameter:
1990: . norm - the last computed residual norm

1992:   Level: developer

1994: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1995: @*/
1996: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
1997: {
2001:   *norm = snes->norm;
2002:   return(0);
2003: }

2005: /*@
2006:   SNESGetUpdateNorm - Gets the last computed norm of the Newton update

2008:   Not Collective

2010:   Input Parameter:
2011: . snes - the SNES context

2013:   Output Parameter:
2014: . ynorm - the last computed update norm

2016:   Level: developer

2018: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), SNESGetFunctionNorm()
2019: @*/
2020: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2021: {
2025:   *ynorm = snes->ynorm;
2026:   return(0);
2027: }

2029: /*@
2030:   SNESGetSolutionNorm - Gets the last computed norm of the solution

2032:   Not Collective

2034:   Input Parameter:
2035: . snes - the SNES context

2037:   Output Parameter:
2038: . xnorm - the last computed solution norm

2040:   Level: developer

2042: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), SNESGetFunctionNorm(), SNESGetUpdateNorm()
2043: @*/
2044: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2045: {
2049:   *xnorm = snes->xnorm;
2050:   return(0);
2051: }

2053: /*@C
2054:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
2055:    of the SNES method.

2057:    Logically Collective on SNES

2059:    Input Parameters:
2060: +  snes - the SNES context
2061: -  normschedule - the frequency of norm computation

2063:    Notes:
2064:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
2065:    of the nonlinear function and the taking of its norm at every iteration to
2066:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
2067:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
2068:    may either be monitored for convergence or not.  As these are often used as nonlinear
2069:    preconditioners, monitoring the norm of their error is not a useful enterprise within
2070:    their solution.

2072:    Level: developer

2074: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2075: @*/
2076: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
2077: {
2080:   snes->functype = type;
2081:   return(0);
2082: }


2085: /*@C
2086:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
2087:    of the SNES method.

2089:    Logically Collective on SNES

2091:    Input Parameters:
2092: +  snes - the SNES context
2093: -  normschedule - the type of the norm used

2095:    Level: advanced

2097: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2098: @*/
2099: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2100: {
2103:   *type = snes->functype;
2104:   return(0);
2105: }

2107: /*MC
2108:     SNESNGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

2110:      Synopsis:
2111: #include <petscsnes.h>
2112: $    SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);

2114:      Collective on snes

2116:      Input Parameters:
2117: +  X   - solution vector
2118: .  B   - RHS vector
2119: -  ctx - optional user-defined Gauss-Seidel context

2121:      Output Parameter:
2122: .  X   - solution vector

2124:    Level: intermediate

2126: .seealso:   SNESSetNGS(), SNESGetNGS()
2127: M*/

2129: /*@C
2130:    SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2131:    use with composed nonlinear solvers.

2133:    Input Parameters:
2134: +  snes   - the SNES context
2135: .  f - function evaluation routine to apply Gauss-Seidel see SNESNGSFunction
2136: -  ctx    - [optional] user-defined context for private data for the
2137:             smoother evaluation routine (may be NULL)

2139:    Notes:
2140:    The NGS routines are used by the composed nonlinear solver to generate
2141:     a problem appropriate update to the solution, particularly FAS.

2143:    Level: intermediate

2145: .seealso: SNESGetFunction(), SNESComputeNGS()
2146: @*/
2147: PetscErrorCode SNESSetNGS(SNES snes,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
2148: {
2150:   DM             dm;

2154:   SNESGetDM(snes,&dm);
2155:   DMSNESSetNGS(dm,f,ctx);
2156:   return(0);
2157: }

2159: PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
2160: {
2162:   DM             dm;
2163:   DMSNES         sdm;

2166:   SNESGetDM(snes,&dm);
2167:   DMGetDMSNES(dm,&sdm);
2168:   if (!sdm->ops->computepfunction) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");
2169:   if (!sdm->ops->computepjacobian) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard Jacobian.");
2170:   /*  A(x)*x - b(x) */
2171:   PetscStackPush("SNES Picard user function");
2172:   (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
2173:   PetscStackPop;
2174:   PetscStackPush("SNES Picard user Jacobian");
2175:   (*sdm->ops->computepjacobian)(snes,x,snes->jacobian,snes->jacobian_pre,sdm->pctx);
2176:   PetscStackPop;
2177:   VecScale(f,-1.0);
2178:   MatMultAdd(snes->jacobian,x,f,f);
2179:   return(0);
2180: }

2182: PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat J,Mat B,void *ctx)
2183: {
2185:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2186:   return(0);
2187: }

2189: /*@C
2190:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

2192:    Logically Collective on SNES

2194:    Input Parameters:
2195: +  snes - the SNES context
2196: .  r - vector to store function value
2197: .  b - function evaluation routine
2198: .  Amat - matrix with which A(x) x - b(x) is to be computed
2199: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
2200: .  J  - function to compute matrix value, see SNESJacobianFunction for details on its calling sequence
2201: -  ctx - [optional] user-defined context for private data for the
2202:          function evaluation routine (may be NULL)

2204:    Notes:
2205:     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
2206:     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.

2208:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

2210: $     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}
2211: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

2213:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

2215:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2216:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

2218:    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
2219:    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
2220:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

2222:    Level: intermediate

2224: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard(), SNESJacobianFunction
2225: @*/
2226: PetscErrorCode  SNESSetPicard(SNES snes,Vec r,PetscErrorCode (*b)(SNES,Vec,Vec,void*),Mat Amat, Mat Pmat, PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2227: {
2229:   DM             dm;

2233:   SNESGetDM(snes, &dm);
2234:   DMSNESSetPicard(dm,b,J,ctx);
2235:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
2236:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
2237:   return(0);
2238: }

2240: /*@C
2241:    SNESGetPicard - Returns the context for the Picard iteration

2243:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

2245:    Input Parameter:
2246: .  snes - the SNES context

2248:    Output Parameter:
2249: +  r - the function (or NULL)
2250: .  f - the function (or NULL); see SNESFunction for calling sequence details
2251: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
2252: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
2253: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
2254: -  ctx - the function context (or NULL)

2256:    Level: advanced

2258: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
2259: @*/
2260: PetscErrorCode  SNESGetPicard(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),Mat *Amat, Mat *Pmat, PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
2261: {
2263:   DM             dm;

2267:   SNESGetFunction(snes,r,NULL,NULL);
2268:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
2269:   SNESGetDM(snes,&dm);
2270:   DMSNESGetPicard(dm,f,J,ctx);
2271:   return(0);
2272: }

2274: /*@C
2275:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

2277:    Logically Collective on SNES

2279:    Input Parameters:
2280: +  snes - the SNES context
2281: .  func - function evaluation routine
2282: -  ctx - [optional] user-defined context for private data for the
2283:          function evaluation routine (may be NULL)

2285:    Calling sequence of func:
2286: $    func (SNES snes,Vec x,void *ctx);

2288: .  f - function vector
2289: -  ctx - optional user-defined function context

2291:    Level: intermediate

2293: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
2294: @*/
2295: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
2296: {
2299:   if (func) snes->ops->computeinitialguess = func;
2300:   if (ctx)  snes->initialguessP            = ctx;
2301:   return(0);
2302: }

2304: /* --------------------------------------------------------------- */
2305: /*@C
2306:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
2307:    it assumes a zero right hand side.

2309:    Logically Collective on SNES

2311:    Input Parameter:
2312: .  snes - the SNES context

2314:    Output Parameter:
2315: .  rhs - the right hand side vector or NULL if the right hand side vector is null

2317:    Level: intermediate

2319: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2320: @*/
2321: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2322: {
2326:   *rhs = snes->vec_rhs;
2327:   return(0);
2328: }

2330: /*@
2331:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2333:    Collective on SNES

2335:    Input Parameters:
2336: +  snes - the SNES context
2337: -  x - input vector

2339:    Output Parameter:
2340: .  y - function vector, as set by SNESSetFunction()

2342:    Notes:
2343:    SNESComputeFunction() is typically used within nonlinear solvers
2344:    implementations, so most users would not generally call this routine
2345:    themselves.

2347:    Level: developer

2349: .seealso: SNESSetFunction(), SNESGetFunction()
2350: @*/
2351: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2352: {
2354:   DM             dm;
2355:   DMSNES         sdm;

2363:   VecValidValues(x,2,PETSC_TRUE);

2365:   SNESGetDM(snes,&dm);
2366:   DMGetDMSNES(dm,&sdm);
2367:   if (sdm->ops->computefunction) {
2368:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2369:       PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2370:     }
2371:     VecLockReadPush(x);
2372:     PetscStackPush("SNES user function");
2373:     /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2374:     snes->domainerror = PETSC_FALSE;
2375:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2376:     PetscStackPop;
2377:     VecLockReadPop(x);
2378:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2379:       PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2380:     }
2381:   } else if (snes->vec_rhs) {
2382:     MatMult(snes->jacobian, x, y);
2383:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2384:   if (snes->vec_rhs) {
2385:     VecAXPY(y,-1.0,snes->vec_rhs);
2386:   }
2387:   snes->nfuncs++;
2388:   /*
2389:      domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2390:      propagate the value to all processes
2391:   */
2392:   if (snes->domainerror) {
2393:     VecSetInf(y);
2394:   }
2395:   return(0);
2396: }

2398: /*@
2399:    SNESComputeNGS - Calls the Gauss-Seidel function that has been set with  SNESSetNGS().

2401:    Collective on SNES

2403:    Input Parameters:
2404: +  snes - the SNES context
2405: .  x - input vector
2406: -  b - rhs vector

2408:    Output Parameter:
2409: .  x - new solution vector

2411:    Notes:
2412:    SNESComputeNGS() is typically used within composed nonlinear solver
2413:    implementations, so most users would not generally call this routine
2414:    themselves.

2416:    Level: developer

2418: .seealso: SNESSetNGS(), SNESComputeFunction()
2419: @*/
2420: PetscErrorCode  SNESComputeNGS(SNES snes,Vec b,Vec x)
2421: {
2423:   DM             dm;
2424:   DMSNES         sdm;

2432:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2433:   PetscLogEventBegin(SNES_NGSEval,snes,x,b,0);
2434:   SNESGetDM(snes,&dm);
2435:   DMGetDMSNES(dm,&sdm);
2436:   if (sdm->ops->computegs) {
2437:     if (b) {VecLockReadPush(b);}
2438:     PetscStackPush("SNES user NGS");
2439:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2440:     PetscStackPop;
2441:     if (b) {VecLockReadPop(b);}
2442:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2443:   PetscLogEventEnd(SNES_NGSEval,snes,x,b,0);
2444:   return(0);
2445: }

2447: PetscErrorCode SNESTestJacobian(SNES snes)
2448: {
2449:   Mat               A,B,C,D,jacobian;
2450:   Vec               x = snes->vec_sol,f = snes->vec_func;
2451:   PetscErrorCode    ierr;
2452:   PetscReal         nrm,gnorm;
2453:   PetscReal         threshold = 1.e-5;
2454:   MatType           mattype;
2455:   PetscInt          m,n,M,N;
2456:   void              *functx;
2457:   PetscBool         complete_print = PETSC_FALSE,threshold_print = PETSC_FALSE,test = PETSC_FALSE,flg,istranspose;
2458:   PetscViewer       viewer,mviewer;
2459:   MPI_Comm          comm;
2460:   PetscInt          tabs;
2461:   static PetscBool  directionsprinted = PETSC_FALSE;
2462:   PetscViewerFormat format;

2465:   PetscObjectOptionsBegin((PetscObject)snes);
2466:   PetscOptionsName("-snes_test_jacobian","Compare hand-coded and finite difference Jacobians","None",&test);
2467:   PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold,NULL);
2468:   PetscOptionsViewer("-snes_test_jacobian_view","View difference between hand-coded and finite difference Jacobians element entries","None",&mviewer,&format,&complete_print);
2469:   if (!complete_print) {
2470:     PetscOptionsDeprecated("-snes_test_jacobian_display","-snes_test_jacobian_view","3.13",NULL);
2471:     PetscOptionsViewer("-snes_test_jacobian_display","Display difference between hand-coded and finite difference Jacobians","None",&mviewer,&format,&complete_print);
2472:   }
2473:   /* for compatibility with PETSc 3.9 and older. */
2474:   PetscOptionsDeprecated("-snes_test_jacobian_display_threshold","-snes_test_jacobian","3.13","-snes_test_jacobian accepts an optional threshold (since v3.10)");
2475:   PetscOptionsReal("-snes_test_jacobian_display_threshold", "Display difference between hand-coded and finite difference Jacobians which exceed input threshold", "None", threshold, &threshold, &threshold_print);
2476:   PetscOptionsEnd();
2477:   if (!test) return(0);

2479:   PetscObjectGetComm((PetscObject)snes,&comm);
2480:   PetscViewerASCIIGetStdout(comm,&viewer);
2481:   PetscViewerASCIIGetTab(viewer, &tabs);
2482:   PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel);
2483:   PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian -------------\n");
2484:   if (!complete_print && !directionsprinted) {
2485:     PetscViewerASCIIPrintf(viewer,"  Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n");
2486:     PetscViewerASCIIPrintf(viewer,"    of hand-coded and finite difference Jacobian entries greater than <threshold>.\n");
2487:   }
2488:   if (!directionsprinted) {
2489:     PetscViewerASCIIPrintf(viewer,"  Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n");
2490:     PetscViewerASCIIPrintf(viewer,"    O(1.e-8), the hand-coded Jacobian is probably correct.\n");
2491:     directionsprinted = PETSC_TRUE;
2492:   }
2493:   if (complete_print) {
2494:     PetscViewerPushFormat(mviewer,format);
2495:   }

2497:   PetscObjectTypeCompare((PetscObject)snes->jacobian,MATMFFD,&flg);
2498:   if (!flg) jacobian = snes->jacobian;
2499:   else jacobian = snes->jacobian_pre;

2501:   if (!x) {
2502:     MatCreateVecs(jacobian, &x, NULL);
2503:   } else {
2504:     PetscObjectReference((PetscObject) x);
2505:   }
2506:   if (!f) {
2507:     VecDuplicate(x, &f);
2508:   } else {
2509:     PetscObjectReference((PetscObject) f);
2510:   }
2511:   /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2512:   SNESComputeFunction(snes,x,f);
2513:   VecDestroy(&f);
2514:   PetscObjectTypeCompare((PetscObject)snes,SNESKSPTRANSPOSEONLY,&istranspose);
2515:   while (jacobian) {
2516:     Mat JT = NULL, Jsave = NULL;

2518:     if (istranspose) {
2519:       MatCreateTranspose(jacobian,&JT);
2520:       Jsave = jacobian;
2521:       jacobian = JT;
2522:     }
2523:     PetscObjectBaseTypeCompareAny((PetscObject)jacobian,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPISBAIJ,"");
2524:     if (flg) {
2525:       A    = jacobian;
2526:       PetscObjectReference((PetscObject)A);
2527:     } else {
2528:       MatComputeOperator(jacobian,MATAIJ,&A);
2529:     }

2531:     MatGetType(A,&mattype);
2532:     MatGetSize(A,&M,&N);
2533:     MatGetLocalSize(A,&m,&n);
2534:     MatCreate(PetscObjectComm((PetscObject)A),&B);
2535:     MatSetType(B,mattype);
2536:     MatSetSizes(B,m,n,M,N);
2537:     MatSetBlockSizesFromMats(B,A,A);
2538:     MatSetUp(B);
2539:     MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2541:     SNESGetFunction(snes,NULL,NULL,&functx);
2542:     SNESComputeJacobianDefault(snes,x,B,B,functx);

2544:     MatDuplicate(B,MAT_COPY_VALUES,&D);
2545:     MatAYPX(D,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2546:     MatNorm(D,NORM_FROBENIUS,&nrm);
2547:     MatNorm(A,NORM_FROBENIUS,&gnorm);
2548:     MatDestroy(&D);
2549:     if (!gnorm) gnorm = 1; /* just in case */
2550:     PetscViewerASCIIPrintf(viewer,"  ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n",(double)(nrm/gnorm),(double)nrm);

2552:     if (complete_print) {
2553:       PetscViewerASCIIPrintf(viewer,"  Hand-coded Jacobian ----------\n");
2554:       MatView(A,mviewer);
2555:       PetscViewerASCIIPrintf(viewer,"  Finite difference Jacobian ----------\n");
2556:       MatView(B,mviewer);
2557:     }

2559:     if (threshold_print || complete_print) {
2560:       PetscInt          Istart, Iend, *ccols, bncols, cncols, j, row;
2561:       PetscScalar       *cvals;
2562:       const PetscInt    *bcols;
2563:       const PetscScalar *bvals;

2565:       MatCreate(PetscObjectComm((PetscObject)A),&C);
2566:       MatSetType(C,mattype);
2567:       MatSetSizes(C,m,n,M,N);
2568:       MatSetBlockSizesFromMats(C,A,A);
2569:       MatSetUp(C);
2570:       MatSetOption(C,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2572:       MatAYPX(B,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2573:       MatGetOwnershipRange(B,&Istart,&Iend);

2575:       for (row = Istart; row < Iend; row++) {
2576:         MatGetRow(B,row,&bncols,&bcols,&bvals);
2577:         PetscMalloc2(bncols,&ccols,bncols,&cvals);
2578:         for (j = 0, cncols = 0; j < bncols; j++) {
2579:           if (PetscAbsScalar(bvals[j]) > threshold) {
2580:             ccols[cncols] = bcols[j];
2581:             cvals[cncols] = bvals[j];
2582:             cncols += 1;
2583:           }
2584:         }
2585:         if (cncols) {
2586:           MatSetValues(C,1,&row,cncols,ccols,cvals,INSERT_VALUES);
2587:         }
2588:         MatRestoreRow(B,row,&bncols,&bcols,&bvals);
2589:         PetscFree2(ccols,cvals);
2590:       }
2591:       MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
2592:       MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
2593:       PetscViewerASCIIPrintf(viewer,"  Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n",(double)threshold);
2594:       MatView(C,complete_print ? mviewer : viewer);
2595:       MatDestroy(&C);
2596:     }
2597:     MatDestroy(&A);
2598:     MatDestroy(&B);
2599:     MatDestroy(&JT);
2600:     if (Jsave) jacobian = Jsave;
2601:     if (jacobian != snes->jacobian_pre) {
2602:       jacobian = snes->jacobian_pre;
2603:       PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian for preconditioner -------------\n");
2604:     }
2605:     else jacobian = NULL;
2606:   }
2607:   VecDestroy(&x);
2608:   if (complete_print) {
2609:     PetscViewerPopFormat(mviewer);
2610:   }
2611:   if (mviewer) { PetscViewerDestroy(&mviewer); }
2612:   PetscViewerASCIISetTab(viewer,tabs);
2613:   return(0);
2614: }

2616: /*@
2617:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2619:    Collective on SNES

2621:    Input Parameters:
2622: +  snes - the SNES context
2623: -  x - input vector

2625:    Output Parameters:
2626: +  A - Jacobian matrix
2627: -  B - optional preconditioning matrix

2629:   Options Database Keys:
2630: +    -snes_lag_preconditioner <lag>
2631: .    -snes_lag_jacobian <lag>
2632: .    -snes_test_jacobian <optional threshold> - compare the user provided Jacobian with one compute via finite differences to check for errors.  If a threshold is given, display only those entries whose difference is greater than the threshold.
2633: .    -snes_test_jacobian_view - display the user provided Jacobian, the finite difference Jacobian and the difference between them to help users detect the location of errors in the user provided Jacobian
2634: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2635: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2636: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2637: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2638: .    -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2639: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2640: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2641: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2642: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2643: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2644: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2647:    Notes:
2648:    Most users should not need to explicitly call this routine, as it
2649:    is used internally within the nonlinear solvers.

2651:    Developer Notes:
2652:     This has duplicative ways of checking the accuracy of the user provided Jacobian (see the options above). This is for historical reasons, the routine SNESTestJacobian() use to used
2653:       for with the SNESType of test that has been removed.

2655:    Level: developer

2657: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2658: @*/
2659: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat A,Mat B)
2660: {
2662:   PetscBool      flag;
2663:   DM             dm;
2664:   DMSNES         sdm;
2665:   KSP            ksp;

2671:   VecValidValues(X,2,PETSC_TRUE);
2672:   SNESGetDM(snes,&dm);
2673:   DMGetDMSNES(dm,&sdm);

2675:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2677:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2679:   if (snes->lagjacobian == -2) {
2680:     snes->lagjacobian = -1;

2682:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2683:   } else if (snes->lagjacobian == -1) {
2684:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2685:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2686:     if (flag) {
2687:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2688:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2689:     }
2690:     return(0);
2691:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2692:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2693:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2694:     if (flag) {
2695:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2696:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2697:     }
2698:     return(0);
2699:   }
2700:   if (snes->npc && snes->npcside== PC_LEFT) {
2701:     MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2702:     MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2703:     return(0);
2704:   }

2706:   PetscLogEventBegin(SNES_JacobianEval,snes,X,A,B);
2707:   VecLockReadPush(X);
2708:   PetscStackPush("SNES user Jacobian function");
2709:   (*sdm->ops->computejacobian)(snes,X,A,B,sdm->jacobianctx);
2710:   PetscStackPop;
2711:   VecLockReadPop(X);
2712:   PetscLogEventEnd(SNES_JacobianEval,snes,X,A,B);

2714:   /* attach latest linearization point to the preconditioning matrix */
2715:   PetscObjectCompose((PetscObject)B,"__SNES_latest_X",(PetscObject)X);

2717:   /* the next line ensures that snes->ksp exists */
2718:   SNESGetKSP(snes,&ksp);
2719:   if (snes->lagpreconditioner == -2) {
2720:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");
2721:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2722:     snes->lagpreconditioner = -1;
2723:   } else if (snes->lagpreconditioner == -1) {
2724:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2725:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2726:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2727:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2728:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2729:   } else {
2730:     PetscInfo(snes,"Rebuilding preconditioner\n");
2731:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2732:   }

2734:   SNESTestJacobian(snes);
2735:   /* make sure user returned a correct Jacobian and preconditioner */
2738:   {
2739:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2740:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit",NULL,NULL,&flag);
2741:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",NULL,NULL,&flag_draw);
2742:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",NULL,NULL,&flag_contour);
2743:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_operator",NULL,NULL,&flag_operator);
2744:     if (flag || flag_draw || flag_contour) {
2745:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2746:       PetscViewer  vdraw,vstdout;
2747:       PetscBool    flg;
2748:       if (flag_operator) {
2749:         MatComputeOperator(A,MATAIJ,&Bexp_mine);
2750:         Bexp = Bexp_mine;
2751:       } else {
2752:         /* See if the preconditioning matrix can be viewed and added directly */
2753:         PetscObjectBaseTypeCompareAny((PetscObject)B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2754:         if (flg) Bexp = B;
2755:         else {
2756:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2757:           MatComputeOperator(B,MATAIJ,&Bexp_mine);
2758:           Bexp = Bexp_mine;
2759:         }
2760:       }
2761:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2762:       SNESComputeJacobianDefault(snes,X,FDexp,FDexp,NULL);
2763:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2764:       if (flag_draw || flag_contour) {
2765:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2766:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2767:       } else vdraw = NULL;
2768:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2769:       if (flag) {MatView(Bexp,vstdout);}
2770:       if (vdraw) {MatView(Bexp,vdraw);}
2771:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2772:       if (flag) {MatView(FDexp,vstdout);}
2773:       if (vdraw) {MatView(FDexp,vdraw);}
2774:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2775:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2776:       if (flag) {MatView(FDexp,vstdout);}
2777:       if (vdraw) {              /* Always use contour for the difference */
2778:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2779:         MatView(FDexp,vdraw);
2780:         PetscViewerPopFormat(vdraw);
2781:       }
2782:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2783:       PetscViewerDestroy(&vdraw);
2784:       MatDestroy(&Bexp_mine);
2785:       MatDestroy(&FDexp);
2786:     }
2787:   }
2788:   {
2789:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2790:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2791:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring",NULL,NULL,&flag);
2792:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_display",NULL,NULL,&flag_display);
2793:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",NULL,NULL,&flag_draw);
2794:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",NULL,NULL,&flag_contour);
2795:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",NULL,NULL,&flag_threshold);
2796:     if (flag_threshold) {
2797:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2798:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2799:     }
2800:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2801:       Mat            Bfd;
2802:       PetscViewer    vdraw,vstdout;
2803:       MatColoring    coloring;
2804:       ISColoring     iscoloring;
2805:       MatFDColoring  matfdcoloring;
2806:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2807:       void           *funcctx;
2808:       PetscReal      norm1,norm2,normmax;

2810:       MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2811:       MatColoringCreate(Bfd,&coloring);
2812:       MatColoringSetType(coloring,MATCOLORINGSL);
2813:       MatColoringSetFromOptions(coloring);
2814:       MatColoringApply(coloring,&iscoloring);
2815:       MatColoringDestroy(&coloring);
2816:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2817:       MatFDColoringSetFromOptions(matfdcoloring);
2818:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2819:       ISColoringDestroy(&iscoloring);

2821:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2822:       SNESGetFunction(snes,NULL,&func,&funcctx);
2823:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2824:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2825:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2826:       MatFDColoringSetFromOptions(matfdcoloring);
2827:       MatFDColoringApply(Bfd,matfdcoloring,X,snes);
2828:       MatFDColoringDestroy(&matfdcoloring);

2830:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2831:       if (flag_draw || flag_contour) {
2832:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2833:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2834:       } else vdraw = NULL;
2835:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2836:       if (flag_display) {MatView(B,vstdout);}
2837:       if (vdraw) {MatView(B,vdraw);}
2838:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2839:       if (flag_display) {MatView(Bfd,vstdout);}
2840:       if (vdraw) {MatView(Bfd,vdraw);}
2841:       MatAYPX(Bfd,-1.0,B,SAME_NONZERO_PATTERN);
2842:       MatNorm(Bfd,NORM_1,&norm1);
2843:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2844:       MatNorm(Bfd,NORM_MAX,&normmax);
2845:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2846:       if (flag_display) {MatView(Bfd,vstdout);}
2847:       if (vdraw) {              /* Always use contour for the difference */
2848:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2849:         MatView(Bfd,vdraw);
2850:         PetscViewerPopFormat(vdraw);
2851:       }
2852:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2854:       if (flag_threshold) {
2855:         PetscInt bs,rstart,rend,i;
2856:         MatGetBlockSize(B,&bs);
2857:         MatGetOwnershipRange(B,&rstart,&rend);
2858:         for (i=rstart; i<rend; i++) {
2859:           const PetscScalar *ba,*ca;
2860:           const PetscInt    *bj,*cj;
2861:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2862:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2863:           MatGetRow(B,i,&bn,&bj,&ba);
2864:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2865:           if (bn != cn) SETERRQ(((PetscObject)A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2866:           for (j=0; j<bn; j++) {
2867:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2868:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2869:               maxentrycol = bj[j];
2870:               maxentry    = PetscRealPart(ba[j]);
2871:             }
2872:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2873:               maxdiffcol = bj[j];
2874:               maxdiff    = PetscRealPart(ca[j]);
2875:             }
2876:             if (rdiff > maxrdiff) {
2877:               maxrdiffcol = bj[j];
2878:               maxrdiff    = rdiff;
2879:             }
2880:           }
2881:           if (maxrdiff > 1) {
2882:             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);
2883:             for (j=0; j<bn; j++) {
2884:               PetscReal rdiff;
2885:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2886:               if (rdiff > 1) {
2887:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2888:               }
2889:             }
2890:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2891:           }
2892:           MatRestoreRow(B,i,&bn,&bj,&ba);
2893:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2894:         }
2895:       }
2896:       PetscViewerDestroy(&vdraw);
2897:       MatDestroy(&Bfd);
2898:     }
2899:   }
2900:   return(0);
2901: }

2903: /*MC
2904:     SNESJacobianFunction - Function used to convey the nonlinear Jacobian of the function to be solved by SNES

2906:      Synopsis:
2907:      #include "petscsnes.h"
2908:      PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);

2910:      Collective on snes

2912:     Input Parameters:
2913: +  x - input vector, the Jacobian is to be computed at this value
2914: -  ctx - [optional] user-defined Jacobian context

2916:     Output Parameters:
2917: +  Amat - the matrix that defines the (approximate) Jacobian
2918: -  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.

2920:    Level: intermediate

2922: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2923: M*/

2925: /*@C
2926:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2927:    location to store the matrix.

2929:    Logically Collective on SNES

2931:    Input Parameters:
2932: +  snes - the SNES context
2933: .  Amat - the matrix that defines the (approximate) Jacobian
2934: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2935: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value), see SNESJacobianFunction for details
2936: -  ctx - [optional] user-defined context for private data for the
2937:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2939:    Notes:
2940:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2941:    each matrix.

2943:    If you know the operator Amat has a null space you can use MatSetNullSpace() and MatSetTransposeNullSpace() to supply the null
2944:    space to Amat and the KSP solvers will automatically use that null space as needed during the solution process.

2946:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2947:    must be a MatFDColoring.

2949:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2950:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2952:    Level: beginner

2954: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J,
2955:           SNESSetPicard(), SNESJacobianFunction
2956: @*/
2957: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2958: {
2960:   DM             dm;

2968:   SNESGetDM(snes,&dm);
2969:   DMSNESSetJacobian(dm,J,ctx);
2970:   if (Amat) {
2971:     PetscObjectReference((PetscObject)Amat);
2972:     MatDestroy(&snes->jacobian);

2974:     snes->jacobian = Amat;
2975:   }
2976:   if (Pmat) {
2977:     PetscObjectReference((PetscObject)Pmat);
2978:     MatDestroy(&snes->jacobian_pre);

2980:     snes->jacobian_pre = Pmat;
2981:   }
2982:   return(0);
2983: }

2985: /*@C
2986:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2987:    provided context for evaluating the Jacobian.

2989:    Not Collective, but Mat object will be parallel if SNES object is

2991:    Input Parameter:
2992: .  snes - the nonlinear solver context

2994:    Output Parameters:
2995: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
2996: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
2997: .  J - location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
2998: -  ctx - location to stash Jacobian ctx (or NULL)

3000:    Level: advanced

3002: .seealso: SNESSetJacobian(), SNESComputeJacobian(), SNESJacobianFunction, SNESGetFunction()
3003: @*/
3004: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
3005: {
3007:   DM             dm;
3008:   DMSNES         sdm;

3012:   if (Amat) *Amat = snes->jacobian;
3013:   if (Pmat) *Pmat = snes->jacobian_pre;
3014:   SNESGetDM(snes,&dm);
3015:   DMGetDMSNES(dm,&sdm);
3016:   if (J) *J = sdm->ops->computejacobian;
3017:   if (ctx) *ctx = sdm->jacobianctx;
3018:   return(0);
3019: }

3021: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3022: {
3024:   DM             dm;
3025:   DMSNES         sdm;

3028:   SNESGetDM(snes,&dm);
3029:   DMGetDMSNES(dm,&sdm);
3030:   if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3031:     DM        dm;
3032:     PetscBool isdense,ismf;

3034:     SNESGetDM(snes,&dm);
3035:     PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre,&isdense,MATSEQDENSE,MATMPIDENSE,MATDENSE,NULL);
3036:     PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre,&ismf,MATMFFD,MATSHELL,NULL);
3037:     if (isdense) {
3038:       DMSNESSetJacobian(dm,SNESComputeJacobianDefault,NULL);
3039:     } else if (!ismf) {
3040:       DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
3041:     }
3042:   }
3043:   return(0);
3044: }

3046: /*@
3047:    SNESSetUp - Sets up the internal data structures for the later use
3048:    of a nonlinear solver.

3050:    Collective on SNES

3052:    Input Parameters:
3053: .  snes - the SNES context

3055:    Notes:
3056:    For basic use of the SNES solvers the user need not explicitly call
3057:    SNESSetUp(), since these actions will automatically occur during
3058:    the call to SNESSolve().  However, if one wishes to control this
3059:    phase separately, SNESSetUp() should be called after SNESCreate()
3060:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

3062:    Level: advanced

3064: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
3065: @*/
3066: PetscErrorCode  SNESSetUp(SNES snes)
3067: {
3069:   DM             dm;
3070:   DMSNES         sdm;
3071:   SNESLineSearch linesearch, pclinesearch;
3072:   void           *lsprectx,*lspostctx;
3073:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
3074:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
3075:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
3076:   Vec            f,fpc;
3077:   void           *funcctx;
3078:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
3079:   void           *jacctx,*appctx;
3080:   Mat            j,jpre;

3084:   if (snes->setupcalled) return(0);
3085:   PetscLogEventBegin(SNES_Setup,snes,0,0,0);

3087:   if (!((PetscObject)snes)->type_name) {
3088:     SNESSetType(snes,SNESNEWTONLS);
3089:   }

3091:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

3093:   SNESGetDM(snes,&dm);
3094:   DMGetDMSNES(dm,&sdm);
3095:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
3096:   SNESSetDefaultComputeJacobian(snes);

3098:   if (!snes->vec_func) {
3099:     DMCreateGlobalVector(dm,&snes->vec_func);
3100:   }

3102:   if (!snes->ksp) {
3103:     SNESGetKSP(snes, &snes->ksp);
3104:   }

3106:   if (snes->linesearch) {
3107:     SNESGetLineSearch(snes, &snes->linesearch);
3108:     SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);
3109:   }

3111:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3112:     snes->mf          = PETSC_TRUE;
3113:     snes->mf_operator = PETSC_FALSE;
3114:   }

3116:   if (snes->npc) {
3117:     /* copy the DM over */
3118:     SNESGetDM(snes,&dm);
3119:     SNESSetDM(snes->npc,dm);

3121:     SNESGetFunction(snes,&f,&func,&funcctx);
3122:     VecDuplicate(f,&fpc);
3123:     SNESSetFunction(snes->npc,fpc,func,funcctx);
3124:     SNESGetJacobian(snes,&j,&jpre,&jac,&jacctx);
3125:     SNESSetJacobian(snes->npc,j,jpre,jac,jacctx);
3126:     SNESGetApplicationContext(snes,&appctx);
3127:     SNESSetApplicationContext(snes->npc,appctx);
3128:     VecDestroy(&fpc);

3130:     /* copy the function pointers over */
3131:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->npc);

3133:     /* default to 1 iteration */
3134:     SNESSetTolerances(snes->npc,0.0,0.0,0.0,1,snes->npc->max_funcs);
3135:     if (snes->npcside==PC_RIGHT) {
3136:       SNESSetNormSchedule(snes->npc,SNES_NORM_FINAL_ONLY);
3137:     } else {
3138:       SNESSetNormSchedule(snes->npc,SNES_NORM_NONE);
3139:     }
3140:     SNESSetFromOptions(snes->npc);

3142:     /* copy the line search context over */
3143:     if (snes->linesearch && snes->npc->linesearch) {
3144:       SNESGetLineSearch(snes,&linesearch);
3145:       SNESGetLineSearch(snes->npc,&pclinesearch);
3146:       SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
3147:       SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
3148:       SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
3149:       SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
3150:       PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
3151:     }
3152:   }
3153:   if (snes->mf) {
3154:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
3155:   }
3156:   if (snes->ops->usercompute && !snes->user) {
3157:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
3158:   }

3160:   snes->jac_iter = 0;
3161:   snes->pre_iter = 0;

3163:   if (snes->ops->setup) {
3164:     (*snes->ops->setup)(snes);
3165:   }

3167:   SNESSetDefaultComputeJacobian(snes);

3169:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3170:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3171:       if (snes->linesearch){
3172:         SNESGetLineSearch(snes,&linesearch);
3173:         SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultNPC);
3174:       }
3175:     }
3176:   }
3177:   PetscLogEventEnd(SNES_Setup,snes,0,0,0);
3178:   snes->setupcalled = PETSC_TRUE;
3179:   return(0);
3180: }

3182: /*@
3183:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

3185:    Collective on SNES

3187:    Input Parameter:
3188: .  snes - iterative context obtained from SNESCreate()

3190:    Level: intermediate

3192:    Notes:
3193:     Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

3195: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
3196: @*/
3197: PetscErrorCode  SNESReset(SNES snes)
3198: {

3203:   if (snes->ops->userdestroy && snes->user) {
3204:     (*snes->ops->userdestroy)((void**)&snes->user);
3205:     snes->user = NULL;
3206:   }
3207:   if (snes->npc) {
3208:     SNESReset(snes->npc);
3209:   }

3211:   if (snes->ops->reset) {
3212:     (*snes->ops->reset)(snes);
3213:   }
3214:   if (snes->ksp) {
3215:     KSPReset(snes->ksp);
3216:   }

3218:   if (snes->linesearch) {
3219:     SNESLineSearchReset(snes->linesearch);
3220:   }

3222:   VecDestroy(&snes->vec_rhs);
3223:   VecDestroy(&snes->vec_sol);
3224:   VecDestroy(&snes->vec_sol_update);
3225:   VecDestroy(&snes->vec_func);
3226:   MatDestroy(&snes->jacobian);
3227:   MatDestroy(&snes->jacobian_pre);
3228:   VecDestroyVecs(snes->nwork,&snes->work);
3229:   VecDestroyVecs(snes->nvwork,&snes->vwork);

3231:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

3233:   snes->nwork       = snes->nvwork = 0;
3234:   snes->setupcalled = PETSC_FALSE;
3235:   return(0);
3236: }

3238: /*@
3239:    SNESConvergedReasonViewCancel - Clears all the reasonview functions for a SNES object.

3241:    Collective on SNES

3243:    Input Parameter:
3244: .  snes - iterative context obtained from SNESCreate()

3246:    Level: intermediate

3248: .seealso: SNESCreate(), SNESDestroy(), SNESReset()
3249: @*/
3250: PetscErrorCode  SNESConvergedReasonViewCancel(SNES snes)
3251: {
3253:   PetscInt       i;

3257:   for (i=0; i<snes->numberreasonviews; i++) {
3258:     if (snes->reasonviewdestroy[i]) {
3259:       (*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]);
3260:     }
3261:   }
3262:   snes->numberreasonviews = 0;
3263:   return(0);
3264: }

3266: /*@
3267:    SNESDestroy - Destroys the nonlinear solver context that was created
3268:    with SNESCreate().

3270:    Collective on SNES

3272:    Input Parameter:
3273: .  snes - the SNES context

3275:    Level: beginner

3277: .seealso: SNESCreate(), SNESSolve()
3278: @*/
3279: PetscErrorCode  SNESDestroy(SNES *snes)
3280: {

3284:   if (!*snes) return(0);
3286:   if (--((PetscObject)(*snes))->refct > 0) {*snes = NULL; return(0);}

3288:   SNESReset((*snes));
3289:   SNESDestroy(&(*snes)->npc);

3291:   /* if memory was published with SAWs then destroy it */
3292:   PetscObjectSAWsViewOff((PetscObject)*snes);
3293:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

3295:   if ((*snes)->dm) {DMCoarsenHookRemove((*snes)->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,*snes);}
3296:   DMDestroy(&(*snes)->dm);
3297:   KSPDestroy(&(*snes)->ksp);
3298:   SNESLineSearchDestroy(&(*snes)->linesearch);

3300:   PetscFree((*snes)->kspconvctx);
3301:   if ((*snes)->ops->convergeddestroy) {
3302:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
3303:   }
3304:   if ((*snes)->conv_hist_alloc) {
3305:     PetscFree2((*snes)->conv_hist,(*snes)->conv_hist_its);
3306:   }
3307:   SNESMonitorCancel((*snes));
3308:   SNESConvergedReasonViewCancel((*snes));
3309:   PetscHeaderDestroy(snes);
3310:   return(0);
3311: }

3313: /* ----------- Routines to set solver parameters ---------- */

3315: /*@
3316:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

3318:    Logically Collective on SNES

3320:    Input Parameters:
3321: +  snes - the SNES context
3322: -  lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3323:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3325:    Options Database Keys:
3326: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3327: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3328: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3329: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag

3331:    Notes:
3332:    The default is 1
3333:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or SNESSetLagPreconditionerPersists() was called

3335:    SNESSetLagPreconditionerPersists() allows using the same uniform lagging (for example every second solve) across multiple solves.

3337:    Level: intermediate

3339: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetLagPreconditionerPersists(),
3340:           SNESSetLagJacobianPersists()

3342: @*/
3343: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
3344: {
3347:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3348:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3350:   snes->lagpreconditioner = lag;
3351:   return(0);
3352: }

3354: /*@
3355:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

3357:    Logically Collective on SNES

3359:    Input Parameters:
3360: +  snes - the SNES context
3361: -  steps - the number of refinements to do, defaults to 0

3363:    Options Database Keys:
3364: .    -snes_grid_sequence <steps>

3366:    Level: intermediate

3368:    Notes:
3369:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3371: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetGridSequence()

3373: @*/
3374: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
3375: {
3379:   snes->gridsequence = steps;
3380:   return(0);
3381: }

3383: /*@
3384:    SNESGetGridSequence - gets the number of steps of grid sequencing that SNES does

3386:    Logically Collective on SNES

3388:    Input Parameter:
3389: .  snes - the SNES context

3391:    Output Parameter:
3392: .  steps - the number of refinements to do, defaults to 0

3394:    Options Database Keys:
3395: .    -snes_grid_sequence <steps>

3397:    Level: intermediate

3399:    Notes:
3400:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3402: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetGridSequence()

3404: @*/
3405: PetscErrorCode  SNESGetGridSequence(SNES snes,PetscInt *steps)
3406: {
3409:   *steps = snes->gridsequence;
3410:   return(0);
3411: }

3413: /*@
3414:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

3416:    Not Collective

3418:    Input Parameter:
3419: .  snes - the SNES context

3421:    Output Parameter:
3422: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3423:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3425:    Options Database Keys:
3426: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3427: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3428: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3429: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag

3431:    Notes:
3432:    The default is 1
3433:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3435:    Level: intermediate

3437: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner(), SNESSetLagJacobianPersists(), SNESSetLagPreconditionerPersists()

3439: @*/
3440: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
3441: {
3444:   *lag = snes->lagpreconditioner;
3445:   return(0);
3446: }

3448: /*@
3449:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
3450:      often the preconditioner is rebuilt.

3452:    Logically Collective on SNES

3454:    Input Parameters:
3455: +  snes - the SNES context
3456: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3457:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

3459:    Options Database Keys:
3460: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3461: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3462: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3463: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag.

3465:    Notes:
3466:    The default is 1
3467:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3468:    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
3469:    at the next Newton step but never again (unless it is reset to another value)

3471:    Level: intermediate

3473: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobianPersists(), SNESSetLagPreconditionerPersists()

3475: @*/
3476: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
3477: {
3480:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3481:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3483:   snes->lagjacobian = lag;
3484:   return(0);
3485: }

3487: /*@
3488:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

3490:    Not Collective

3492:    Input Parameter:
3493: .  snes - the SNES context

3495:    Output Parameter:
3496: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3497:          the Jacobian is built etc.

3499:    Notes:
3500:    The default is 1
3501:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or SNESSetLagJacobianPersists() was called.

3503:    Level: intermediate

3505: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner(), SNESSetLagJacobianPersists(), SNESSetLagPreconditionerPersists()

3507: @*/
3508: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
3509: {
3512:   *lag = snes->lagjacobian;
3513:   return(0);
3514: }

3516: /*@
3517:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

3519:    Logically collective on SNES

3521:    Input Parameter:
3522: +  snes - the SNES context
3523: -   flg - jacobian lagging persists if true

3525:    Options Database Keys:
3526: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3527: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3528: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3529: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag


3532:    Notes:
3533:     This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3534:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3535:    timesteps may present huge efficiency gains.

3537:    Level: developer

3539: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC(), SNESSetLagJacobianPersists()

3541: @*/
3542: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3543: {
3547:   snes->lagjac_persist = flg;
3548:   return(0);
3549: }

3551: /*@
3552:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves

3554:    Logically Collective on SNES

3556:    Input Parameter:
3557: +  snes - the SNES context
3558: -   flg - preconditioner lagging persists if true

3560:    Options Database Keys:
3561: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3562: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3563: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3564: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag

3566:    Notes:
3567:     This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3568:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3569:    several timesteps may present huge efficiency gains.

3571:    Level: developer

3573: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC(), SNESSetLagPreconditioner()

3575: @*/
3576: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3577: {
3581:   snes->lagpre_persist = flg;
3582:   return(0);
3583: }

3585: /*@
3586:    SNESSetForceIteration - force SNESSolve() to take at least one iteration regardless of the initial residual norm

3588:    Logically Collective on SNES

3590:    Input Parameters:
3591: +  snes - the SNES context
3592: -  force - PETSC_TRUE require at least one iteration

3594:    Options Database Keys:
3595: .    -snes_force_iteration <force> - Sets forcing an iteration

3597:    Notes:
3598:    This is used sometimes with TS to prevent TS from detecting a false steady state solution

3600:    Level: intermediate

3602: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3603: @*/
3604: PetscErrorCode  SNESSetForceIteration(SNES snes,PetscBool force)
3605: {
3608:   snes->forceiteration = force;
3609:   return(0);
3610: }

3612: /*@
3613:    SNESGetForceIteration - Whether or not to force SNESSolve() take at least one iteration regardless of the initial residual norm

3615:    Logically Collective on SNES

3617:    Input Parameters:
3618: .  snes - the SNES context

3620:    Output Parameter:
3621: .  force - PETSC_TRUE requires at least one iteration.

3623:    Level: intermediate

3625: .seealso: SNESSetForceIteration(), SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3626: @*/
3627: PetscErrorCode  SNESGetForceIteration(SNES snes,PetscBool *force)
3628: {
3631:   *force = snes->forceiteration;
3632:   return(0);
3633: }

3635: /*@
3636:    SNESSetTolerances - Sets various parameters used in convergence tests.

3638:    Logically Collective on SNES

3640:    Input Parameters:
3641: +  snes - the SNES context
3642: .  abstol - absolute convergence tolerance
3643: .  rtol - relative convergence tolerance
3644: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3645: .  maxit - maximum number of iterations
3646: -  maxf - maximum number of function evaluations (-1 indicates no limit)

3648:    Options Database Keys:
3649: +    -snes_atol <abstol> - Sets abstol
3650: .    -snes_rtol <rtol> - Sets rtol
3651: .    -snes_stol <stol> - Sets stol
3652: .    -snes_max_it <maxit> - Sets maxit
3653: -    -snes_max_funcs <maxf> - Sets maxf

3655:    Notes:
3656:    The default maximum number of iterations is 50.
3657:    The default maximum number of function evaluations is 1000.

3659:    Level: intermediate

3661: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance(), SNESSetForceIteration()
3662: @*/
3663: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3664: {

3673:   if (abstol != PETSC_DEFAULT) {
3674:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3675:     snes->abstol = abstol;
3676:   }
3677:   if (rtol != PETSC_DEFAULT) {
3678:     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);
3679:     snes->rtol = rtol;
3680:   }
3681:   if (stol != PETSC_DEFAULT) {
3682:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3683:     snes->stol = stol;
3684:   }
3685:   if (maxit != PETSC_DEFAULT) {
3686:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3687:     snes->max_its = maxit;
3688:   }
3689:   if (maxf != PETSC_DEFAULT) {
3690:     if (maxf < -1) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be -1 or nonnegative",maxf);
3691:     snes->max_funcs = maxf;
3692:   }
3693:   snes->tolerancesset = PETSC_TRUE;
3694:   return(0);
3695: }

3697: /*@
3698:    SNESSetDivergenceTolerance - Sets the divergence tolerance used for the SNES divergence test.

3700:    Logically Collective on SNES

3702:    Input Parameters:
3703: +  snes - the SNES context
3704: -  divtol - the divergence tolerance. Use -1 to deactivate the test.

3706:    Options Database Keys:
3707: .    -snes_divergence_tolerance <divtol> - Sets divtol

3709:    Notes:
3710:    The default divergence tolerance is 1e4.

3712:    Level: intermediate

3714: .seealso: SNESSetTolerances(), SNESGetDivergenceTolerance
3715: @*/
3716: PetscErrorCode  SNESSetDivergenceTolerance(SNES snes,PetscReal divtol)
3717: {

3722:   if (divtol != PETSC_DEFAULT) {
3723:     snes->divtol = divtol;
3724:   }
3725:   else {
3726:     snes->divtol = 1.0e4;
3727:   }
3728:   return(0);
3729: }

3731: /*@
3732:    SNESGetTolerances - Gets various parameters used in convergence tests.

3734:    Not Collective

3736:    Input Parameters:
3737: +  snes - the SNES context
3738: .  atol - absolute convergence tolerance
3739: .  rtol - relative convergence tolerance
3740: .  stol -  convergence tolerance in terms of the norm
3741:            of the change in the solution between steps
3742: .  maxit - maximum number of iterations
3743: -  maxf - maximum number of function evaluations

3745:    Notes:
3746:    The user can specify NULL for any parameter that is not needed.

3748:    Level: intermediate

3750: .seealso: SNESSetTolerances()
3751: @*/
3752: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3753: {
3756:   if (atol)  *atol  = snes->abstol;
3757:   if (rtol)  *rtol  = snes->rtol;
3758:   if (stol)  *stol  = snes->stol;
3759:   if (maxit) *maxit = snes->max_its;
3760:   if (maxf)  *maxf  = snes->max_funcs;
3761:   return(0);
3762: }

3764: /*@
3765:    SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.

3767:    Not Collective

3769:    Input Parameters:
3770: +  snes - the SNES context
3771: -  divtol - divergence tolerance

3773:    Level: intermediate

3775: .seealso: SNESSetDivergenceTolerance()
3776: @*/
3777: PetscErrorCode  SNESGetDivergenceTolerance(SNES snes,PetscReal *divtol)
3778: {
3781:   if (divtol) *divtol = snes->divtol;
3782:   return(0);
3783: }

3785: /*@
3786:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3788:    Logically Collective on SNES

3790:    Input Parameters:
3791: +  snes - the SNES context
3792: -  tol - tolerance

3794:    Options Database Key:
3795: .  -snes_trtol <tol> - Sets tol

3797:    Level: intermediate

3799: .seealso: SNESSetTolerances()
3800: @*/
3801: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3802: {
3806:   snes->deltatol = tol;
3807:   return(0);
3808: }

3810: PETSC_INTERN PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);

3812: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3813: {
3814:   PetscDrawLG      lg;
3815:   PetscErrorCode   ierr;
3816:   PetscReal        x,y,per;
3817:   PetscViewer      v = (PetscViewer)monctx;
3818:   static PetscReal prev; /* should be in the context */
3819:   PetscDraw        draw;

3823:   PetscViewerDrawGetDrawLG(v,0,&lg);
3824:   if (!n) {PetscDrawLGReset(lg);}
3825:   PetscDrawLGGetDraw(lg,&draw);
3826:   PetscDrawSetTitle(draw,"Residual norm");
3827:   x    = (PetscReal)n;
3828:   if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3829:   else y = -15.0;
3830:   PetscDrawLGAddPoint(lg,&x,&y);
3831:   if (n < 20 || !(n % 5) || snes->reason) {
3832:     PetscDrawLGDraw(lg);
3833:     PetscDrawLGSave(lg);
3834:   }

3836:   PetscViewerDrawGetDrawLG(v,1,&lg);
3837:   if (!n) {PetscDrawLGReset(lg);}
3838:   PetscDrawLGGetDraw(lg,&draw);
3839:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3840:    SNESMonitorRange_Private(snes,n,&per);
3841:   x    = (PetscReal)n;
3842:   y    = 100.0*per;
3843:   PetscDrawLGAddPoint(lg,&x,&y);
3844:   if (n < 20 || !(n % 5) || snes->reason) {
3845:     PetscDrawLGDraw(lg);
3846:     PetscDrawLGSave(lg);
3847:   }

3849:   PetscViewerDrawGetDrawLG(v,2,&lg);
3850:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3851:   PetscDrawLGGetDraw(lg,&draw);
3852:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3853:   x    = (PetscReal)n;
3854:   y    = (prev - rnorm)/prev;
3855:   PetscDrawLGAddPoint(lg,&x,&y);
3856:   if (n < 20 || !(n % 5) || snes->reason) {
3857:     PetscDrawLGDraw(lg);
3858:     PetscDrawLGSave(lg);
3859:   }

3861:   PetscViewerDrawGetDrawLG(v,3,&lg);
3862:   if (!n) {PetscDrawLGReset(lg);}
3863:   PetscDrawLGGetDraw(lg,&draw);
3864:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3865:   x    = (PetscReal)n;
3866:   y    = (prev - rnorm)/(prev*per);
3867:   if (n > 2) { /*skip initial crazy value */
3868:     PetscDrawLGAddPoint(lg,&x,&y);
3869:   }
3870:   if (n < 20 || !(n % 5) || snes->reason) {
3871:     PetscDrawLGDraw(lg);
3872:     PetscDrawLGSave(lg);
3873:   }
3874:   prev = rnorm;
3875:   return(0);
3876: }

3878: /*@
3879:    SNESMonitor - runs the user provided monitor routines, if they exist

3881:    Collective on SNES

3883:    Input Parameters:
3884: +  snes - nonlinear solver context obtained from SNESCreate()
3885: .  iter - iteration number
3886: -  rnorm - relative norm of the residual

3888:    Notes:
3889:    This routine is called by the SNES implementations.
3890:    It does not typically need to be called by the user.

3892:    Level: developer

3894: .seealso: SNESMonitorSet()
3895: @*/
3896: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3897: {
3899:   PetscInt       i,n = snes->numbermonitors;

3902:   VecLockReadPush(snes->vec_sol);
3903:   for (i=0; i<n; i++) {
3904:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3905:   }
3906:   VecLockReadPop(snes->vec_sol);
3907:   return(0);
3908: }

3910: /* ------------ Routines to set performance monitoring options ----------- */

3912: /*MC
3913:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3915:      Synopsis:
3916: #include <petscsnes.h>
3917: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3919:      Collective on snes

3921:     Input Parameters:
3922: +    snes - the SNES context
3923: .    its - iteration number
3924: .    norm - 2-norm function value (may be estimated)
3925: -    mctx - [optional] monitoring context

3927:    Level: advanced

3929: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3930: M*/

3932: /*@C
3933:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3934:    iteration of the nonlinear solver to display the iteration's
3935:    progress.

3937:    Logically Collective on SNES

3939:    Input Parameters:
3940: +  snes - the SNES context
3941: .  f - the monitor function, see SNESMonitorFunction for the calling sequence
3942: .  mctx - [optional] user-defined context for private data for the
3943:           monitor routine (use NULL if no context is desired)
3944: -  monitordestroy - [optional] routine that frees monitor context
3945:           (may be NULL)

3947:    Options Database Keys:
3948: +    -snes_monitor        - sets SNESMonitorDefault()
3949: .    -snes_monitor draw::draw_lg - sets line graph monitor,
3950: -    -snes_monitor_cancel - cancels all monitors that have
3951:                             been hardwired into a code by
3952:                             calls to SNESMonitorSet(), but
3953:                             does not cancel those set via
3954:                             the options database.

3956:    Notes:
3957:    Several different monitoring routines may be set by calling
3958:    SNESMonitorSet() multiple times; all will be called in the
3959:    order in which they were set.

3961:    Fortran Notes:
3962:     Only a single monitor function can be set for each SNES object

3964:    Level: intermediate

3966: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3967: @*/
3968: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*f)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3969: {
3970:   PetscInt       i;
3972:   PetscBool      identical;

3976:   for (i=0; i<snes->numbermonitors;i++) {
3977:     PetscMonitorCompare((PetscErrorCode (*)(void))f,mctx,monitordestroy,(PetscErrorCode (*)(void))snes->monitor[i],snes->monitorcontext[i],snes->monitordestroy[i],&identical);
3978:     if (identical) return(0);
3979:   }
3980:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3981:   snes->monitor[snes->numbermonitors]          = f;
3982:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3983:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3984:   return(0);
3985: }

3987: /*@
3988:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3990:    Logically Collective on SNES

3992:    Input Parameters:
3993: .  snes - the SNES context

3995:    Options Database Key:
3996: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
3997:     into a code by calls to SNESMonitorSet(), but does not cancel those
3998:     set via the options database

4000:    Notes:
4001:    There is no way to clear one specific monitor from a SNES object.

4003:    Level: intermediate

4005: .seealso: SNESMonitorDefault(), SNESMonitorSet()
4006: @*/
4007: PetscErrorCode  SNESMonitorCancel(SNES snes)
4008: {
4010:   PetscInt       i;

4014:   for (i=0; i<snes->numbermonitors; i++) {
4015:     if (snes->monitordestroy[i]) {
4016:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
4017:     }
4018:   }
4019:   snes->numbermonitors = 0;
4020:   return(0);
4021: }

4023: /*MC
4024:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

4026:      Synopsis:
4027: #include <petscsnes.h>
4028: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

4030:      Collective on snes

4032:     Input Parameters:
4033: +    snes - the SNES context
4034: .    it - current iteration (0 is the first and is before any Newton step)
4035: .    xnorm - 2-norm of current iterate
4036: .    gnorm - 2-norm of current step
4037: .    f - 2-norm of function
4038: -    cctx - [optional] convergence context

4040:     Output Parameter:
4041: .    reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected

4043:    Level: intermediate

4045: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
4046: M*/

4048: /*@C
4049:    SNESSetConvergenceTest - Sets the function that is to be used
4050:    to test for convergence of the nonlinear iterative solution.

4052:    Logically Collective on SNES

4054:    Input Parameters:
4055: +  snes - the SNES context
4056: .  SNESConvergenceTestFunction - routine to test for convergence
4057: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
4058: -  destroy - [optional] destructor for the context (may be NULL; PETSC_NULL_FUNCTION in Fortran)

4060:    Level: advanced

4062: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
4063: @*/
4064: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
4065: {

4070:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4071:   if (snes->ops->convergeddestroy) {
4072:     (*snes->ops->convergeddestroy)(snes->cnvP);
4073:   }
4074:   snes->ops->converged        = SNESConvergenceTestFunction;
4075:   snes->ops->convergeddestroy = destroy;
4076:   snes->cnvP                  = cctx;
4077:   return(0);
4078: }

4080: /*@
4081:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

4083:    Not Collective

4085:    Input Parameter:
4086: .  snes - the SNES context

4088:    Output Parameter:
4089: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
4090:             manual pages for the individual convergence tests for complete lists

4092:    Options Database:
4093: .   -snes_converged_reason - prints the reason to standard out

4095:    Level: intermediate

4097:    Notes:
4098:     Should only be called after the call the SNESSolve() is complete, if it is called earlier it returns the value SNES__CONVERGED_ITERATING.

4100: .seealso: SNESSetConvergenceTest(), SNESSetConvergedReason(), SNESConvergedReason
4101: @*/
4102: PetscErrorCode SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
4103: {
4107:   *reason = snes->reason;
4108:   return(0);
4109: }

4111: /*@C
4112:    SNESGetConvergedReasonString - Return a human readable string for snes converged reason

4114:    Not Collective

4116:    Input Parameter:
4117: .  snes - the SNES context

4119:    Output Parameter:
4120: .  strreason - a human readable string that describes SNES converged reason

4122:    Level: basic

4124: .seealso: SNESGetConvergedReason()
4125: @*/
4126: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char** strreason)
4127: {
4131:   *strreason = SNESConvergedReasons[snes->reason];
4132:   return(0);
4133: }

4135: /*@
4136:    SNESSetConvergedReason - Sets the reason the SNES iteration was stopped.

4138:    Not Collective

4140:    Input Parameters:
4141: +  snes - the SNES context
4142: -  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
4143:             manual pages for the individual convergence tests for complete lists

4145:    Level: intermediate

4147: .seealso: SNESGetConvergedReason(), SNESSetConvergenceTest(), SNESConvergedReason
4148: @*/
4149: PetscErrorCode SNESSetConvergedReason(SNES snes,SNESConvergedReason reason)
4150: {
4153:   snes->reason = reason;
4154:   return(0);
4155: }

4157: /*@
4158:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

4160:    Logically Collective on SNES

4162:    Input Parameters:
4163: +  snes - iterative context obtained from SNESCreate()
4164: .  a   - array to hold history, this array will contain the function norms computed at each step
4165: .  its - integer array holds the number of linear iterations for each solve.
4166: .  na  - size of a and its
4167: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
4168:            else it continues storing new values for new nonlinear solves after the old ones

4170:    Notes:
4171:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
4172:    default array of length 10000 is allocated.

4174:    This routine is useful, e.g., when running a code for purposes
4175:    of accurate performance monitoring, when no I/O should be done
4176:    during the section of code that is being timed.

4178:    Level: intermediate

4180: .seealso: SNESGetConvergenceHistory()

4182: @*/
4183: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
4184: {

4191:   if (!a) {
4192:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
4193:     PetscCalloc2(na,&a,na,&its);
4194:     snes->conv_hist_alloc = PETSC_TRUE;
4195:   }
4196:   snes->conv_hist       = a;
4197:   snes->conv_hist_its   = its;
4198:   snes->conv_hist_max   = na;
4199:   snes->conv_hist_len   = 0;
4200:   snes->conv_hist_reset = reset;
4201:   return(0);
4202: }

4204: #if defined(PETSC_HAVE_MATLAB_ENGINE)
4205: #include <engine.h>   /* MATLAB include file */
4206: #include <mex.h>      /* MATLAB include file */

4208: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4209: {
4210:   mxArray   *mat;
4211:   PetscInt  i;
4212:   PetscReal *ar;

4215:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
4216:   ar  = (PetscReal*) mxGetData(mat);
4217:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4218:   PetscFunctionReturn(mat);
4219: }
4220: #endif

4222: /*@C
4223:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

4225:    Not Collective

4227:    Input Parameter:
4228: .  snes - iterative context obtained from SNESCreate()

4230:    Output Parameters:
4231: +  a   - array to hold history
4232: .  its - integer array holds the number of linear iterations (or
4233:          negative if not converged) for each solve.
4234: -  na  - size of a and its

4236:    Notes:
4237:     The calling sequence for this routine in Fortran is
4238: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

4240:    This routine is useful, e.g., when running a code for purposes
4241:    of accurate performance monitoring, when no I/O should be done
4242:    during the section of code that is being timed.

4244:    Level: intermediate

4246: .seealso: SNESSetConvergenceHistory()

4248: @*/
4249: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
4250: {
4253:   if (a)   *a   = snes->conv_hist;
4254:   if (its) *its = snes->conv_hist_its;
4255:   if (na)  *na  = snes->conv_hist_len;
4256:   return(0);
4257: }

4259: /*@C
4260:   SNESSetUpdate - Sets the general-purpose update function called
4261:   at the beginning of every iteration of the nonlinear solve. Specifically
4262:   it is called just before the Jacobian is "evaluated".

4264:   Logically Collective on SNES

4266:   Input Parameters:
4267: + snes - The nonlinear solver context
4268: - func - The function

4270:   Calling sequence of func:
4271: $ func (SNES snes, PetscInt step);

4273: . step - The current step of the iteration

4275:   Level: advanced

4277:   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()
4278:         This is not used by most users.

4280: .seealso SNESSetJacobian(), SNESSolve()
4281: @*/
4282: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
4283: {
4286:   snes->ops->update = func;
4287:   return(0);
4288: }

4290: /*
4291:    SNESScaleStep_Private - Scales a step so that its length is less than the
4292:    positive parameter delta.

4294:     Input Parameters:
4295: +   snes - the SNES context
4296: .   y - approximate solution of linear system
4297: .   fnorm - 2-norm of current function
4298: -   delta - trust region size

4300:     Output Parameters:
4301: +   gpnorm - predicted function norm at the new point, assuming local
4302:     linearization.  The value is zero if the step lies within the trust
4303:     region, and exceeds zero otherwise.
4304: -   ynorm - 2-norm of the step

4306:     Note:
4307:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
4308:     is set to be the maximum allowable step size.

4310: */
4311: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
4312: {
4313:   PetscReal      nrm;
4314:   PetscScalar    cnorm;


4322:   VecNorm(y,NORM_2,&nrm);
4323:   if (nrm > *delta) {
4324:     nrm     = *delta/nrm;
4325:     *gpnorm = (1.0 - nrm)*(*fnorm);
4326:     cnorm   = nrm;
4327:     VecScale(y,cnorm);
4328:     *ynorm  = *delta;
4329:   } else {
4330:     *gpnorm = 0.0;
4331:     *ynorm  = nrm;
4332:   }
4333:   return(0);
4334: }

4336: /*@C
4337:    SNESConvergedReasonView - Displays the reason a SNES solve converged or diverged to a viewer

4339:    Collective on SNES

4341:    Parameter:
4342: +  snes - iterative context obtained from SNESCreate()
4343: -  viewer - the viewer to display the reason


4346:    Options Database Keys:
4347: +  -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4348: -  -snes_converged_reason ::failed - only print reason and number of iterations when diverged

4350:   Notes:
4351:      To change the format of the output call PetscViewerPushFormat(viewer,format) before this call. Use PETSC_VIEWER_DEFAULT for the default,
4352:      use PETSC_VIEWER_FAILED to only display a reason if it fails.

4354:    Level: beginner

4356: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault(), SNESGetConvergedReason(), SNESConvergedReasonViewFromOptions(),
4357:           PetscViewerPushFormat(), PetscViewerPopFormat()

4359: @*/
4360: PetscErrorCode  SNESConvergedReasonView(SNES snes,PetscViewer viewer)
4361: {
4362:   PetscViewerFormat format;
4363:   PetscBool         isAscii;
4364:   PetscErrorCode    ierr;

4367:   if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4368:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isAscii);
4369:   if (isAscii) {
4370:     PetscViewerGetFormat(viewer, &format);
4371:     PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);
4372:     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4373:       DM              dm;
4374:       Vec             u;
4375:       PetscDS         prob;
4376:       PetscInt        Nf, f;
4377:       PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4378:       void            **exactCtx;
4379:       PetscReal       error;

4381:       SNESGetDM(snes, &dm);
4382:       SNESGetSolution(snes, &u);
4383:       DMGetDS(dm, &prob);
4384:       PetscDSGetNumFields(prob, &Nf);
4385:       PetscMalloc2(Nf, &exactSol, Nf, &exactCtx);
4386:       for (f = 0; f < Nf; ++f) {PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]);}
4387:       DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error);
4388:       PetscFree2(exactSol, exactCtx);
4389:       if (error < 1.0e-11) {PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n");}
4390:       else                 {PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", error);}
4391:     }
4392:     if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4393:       if (((PetscObject) snes)->prefix) {
4394:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve converged due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4395:       } else {
4396:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4397:       }
4398:     } else if (snes->reason <= 0) {
4399:       if (((PetscObject) snes)->prefix) {
4400:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve did not converge due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4401:       } else {
4402:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4403:       }
4404:     }
4405:     PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);
4406:   }
4407:   return(0);
4408: }

4410: /*@C
4411:    SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4412:     end of the nonlinear solver to display the conver reason of the nonlinear solver.

4414:    Logically Collective on SNES

4416:    Input Parameters:
4417: +  snes - the SNES context
4418: .  f - the snes converged reason view function
4419: .  vctx - [optional] user-defined context for private data for the
4420:           snes converged reason view routine (use NULL if no context is desired)
4421: -  reasonviewdestroy - [optional] routine that frees reasonview context
4422:           (may be NULL)

4424:    Options Database Keys:
4425: +    -snes_converged_reason        - sets a default SNESConvergedReasonView()
4426: -    -snes_converged_reason_view_cancel - cancels all converged reason viewers that have
4427:                             been hardwired into a code by
4428:                             calls to SNESConvergedReasonViewSet(), but
4429:                             does not cancel those set via
4430:                             the options database.

4432:    Notes:
4433:    Several different converged reason view routines may be set by calling
4434:    SNESConvergedReasonViewSet() multiple times; all will be called in the
4435:    order in which they were set.

4437:    Level: intermediate

4439: .seealso: SNESConvergedReasonView(), SNESConvergedReasonViewCancel()
4440: @*/
4441: PetscErrorCode  SNESConvergedReasonViewSet(SNES snes,PetscErrorCode (*f)(SNES,void*),void *vctx,PetscErrorCode (*reasonviewdestroy)(void**))
4442: {
4443:   PetscInt       i;
4445:   PetscBool      identical;

4449:   for (i=0; i<snes->numberreasonviews;i++) {
4450:     PetscMonitorCompare((PetscErrorCode (*)(void))f,vctx,reasonviewdestroy,(PetscErrorCode (*)(void))snes->reasonview[i],snes->reasonviewcontext[i],snes->reasonviewdestroy[i],&identical);
4451:     if (identical) return(0);
4452:   }
4453:   if (snes->numberreasonviews >= MAXSNESREASONVIEWS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many SNES reasonview set");
4454:   snes->reasonview[snes->numberreasonviews]          = f;
4455:   snes->reasonviewdestroy[snes->numberreasonviews]   = reasonviewdestroy;
4456:   snes->reasonviewcontext[snes->numberreasonviews++] = (void*)vctx;
4457:   return(0);
4458: }

4460: /*@
4461:   SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a SNESReason is to be viewed.
4462:                                        All the user-provided convergedReasonView routines will be involved as well, if they exist.

4464:   Collective on SNES

4466:   Input Parameters:
4467: . snes   - the SNES object

4469:   Level: intermediate

4471: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault(), SNESGetConvergedReason(), SNESConvergedReasonView()

4473: @*/
4474: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4475: {
4476:   PetscErrorCode    ierr;
4477:   PetscViewer       viewer;
4478:   PetscBool         flg;
4479:   static PetscBool  incall = PETSC_FALSE;
4480:   PetscViewerFormat format;
4481:   PetscInt          i;

4484:   if (incall) return(0);
4485:   incall = PETSC_TRUE;

4487:   /* All user-provided viewers are called first, if they exist. */
4488:   for (i=0; i<snes->numberreasonviews; i++) {
4489:     (*snes->reasonview[i])(snes,snes->reasonviewcontext[i]);
4490:   }

4492:   /* Call PETSc default routine if users ask for it */
4493:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_converged_reason",&viewer,&format,&flg);
4494:   if (flg) {
4495:     PetscViewerPushFormat(viewer,format);
4496:     SNESConvergedReasonView(snes,viewer);
4497:     PetscViewerPopFormat(viewer);
4498:     PetscViewerDestroy(&viewer);
4499:   }
4500:   incall = PETSC_FALSE;
4501:   return(0);
4502: }

4504: /*@
4505:    SNESSolve - Solves a nonlinear system F(x) = b.
4506:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

4508:    Collective on SNES

4510:    Input Parameters:
4511: +  snes - the SNES context
4512: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
4513: -  x - the solution vector.

4515:    Notes:
4516:    The user should initialize the vector,x, with the initial guess
4517:    for the nonlinear solve prior to calling SNESSolve.  In particular,
4518:    to employ an initial guess of zero, the user should explicitly set
4519:    this vector to zero by calling VecSet().

4521:    Level: beginner

4523: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
4524: @*/
4525: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
4526: {
4527:   PetscErrorCode    ierr;
4528:   PetscBool         flg;
4529:   PetscInt          grid;
4530:   Vec               xcreated = NULL;
4531:   DM                dm;


4540:   /* High level operations using the nonlinear solver */
4541:   {
4542:     PetscViewer       viewer;
4543:     PetscViewerFormat format;
4544:     PetscInt          num;
4545:     PetscBool         flg;
4546:     static PetscBool  incall = PETSC_FALSE;

4548:     if (!incall) {
4549:       /* Estimate the convergence rate of the discretization */
4550:       PetscOptionsGetViewer(PetscObjectComm((PetscObject) snes),((PetscObject)snes)->options, ((PetscObject) snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg);
4551:       if (flg) {
4552:         PetscConvEst conv;
4553:         DM           dm;
4554:         PetscReal   *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4555:         PetscInt     Nf;

4557:         incall = PETSC_TRUE;
4558:         SNESGetDM(snes, &dm);
4559:         DMGetNumFields(dm, &Nf);
4560:         PetscCalloc1(Nf, &alpha);
4561:         PetscConvEstCreate(PetscObjectComm((PetscObject) snes), &conv);
4562:         PetscConvEstSetSolver(conv, (PetscObject) snes);
4563:         PetscConvEstSetFromOptions(conv);
4564:         PetscConvEstSetUp(conv);
4565:         PetscConvEstGetConvRate(conv, alpha);
4566:         PetscViewerPushFormat(viewer, format);
4567:         PetscConvEstRateView(conv, alpha, viewer);
4568:         PetscViewerPopFormat(viewer);
4569:         PetscViewerDestroy(&viewer);
4570:         PetscConvEstDestroy(&conv);
4571:         PetscFree(alpha);
4572:         incall = PETSC_FALSE;
4573:       }
4574:       /* Adaptively refine the initial grid */
4575:       num  = 1;
4576:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_initial", &num, &flg);
4577:       if (flg) {
4578:         DMAdaptor adaptor;

4580:         incall = PETSC_TRUE;
4581:         DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor);
4582:         DMAdaptorSetSolver(adaptor, snes);
4583:         DMAdaptorSetSequenceLength(adaptor, num);
4584:         DMAdaptorSetFromOptions(adaptor);
4585:         DMAdaptorSetUp(adaptor);
4586:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x);
4587:         DMAdaptorDestroy(&adaptor);
4588:         incall = PETSC_FALSE;
4589:       }
4590:       /* Use grid sequencing to adapt */
4591:       num  = 0;
4592:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_sequence", &num, NULL);
4593:       if (num) {
4594:         DMAdaptor adaptor;

4596:         incall = PETSC_TRUE;
4597:         DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor);
4598:         DMAdaptorSetSolver(adaptor, snes);
4599:         DMAdaptorSetSequenceLength(adaptor, num);
4600:         DMAdaptorSetFromOptions(adaptor);
4601:         DMAdaptorSetUp(adaptor);
4602:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x);
4603:         DMAdaptorDestroy(&adaptor);
4604:         incall = PETSC_FALSE;
4605:       }
4606:     }
4607:   }
4608:   if (!x) {
4609:     SNESGetDM(snes,&dm);
4610:     DMCreateGlobalVector(dm,&xcreated);
4611:     x    = xcreated;
4612:   }
4613:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

4615:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
4616:   for (grid=0; grid<snes->gridsequence+1; grid++) {

4618:     /* set solution vector */
4619:     if (!grid) {PetscObjectReference((PetscObject)x);}
4620:     VecDestroy(&snes->vec_sol);
4621:     snes->vec_sol = x;
4622:     SNESGetDM(snes,&dm);

4624:     /* set affine vector if provided */
4625:     if (b) { PetscObjectReference((PetscObject)b); }
4626:     VecDestroy(&snes->vec_rhs);
4627:     snes->vec_rhs = b;

4629:     if (snes->vec_rhs && (snes->vec_func == snes->vec_rhs)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Right hand side vector cannot be function vector");
4630:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
4631:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
4632:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
4633:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
4634:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
4635:     }
4636:     DMShellSetGlobalVector(dm,snes->vec_sol);
4637:     SNESSetUp(snes);

4639:     if (!grid) {
4640:       if (snes->ops->computeinitialguess) {
4641:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
4642:       }
4643:     }

4645:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4646:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

4648:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
4649:     (*snes->ops->solve)(snes);
4650:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
4651:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");
4652:     snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */

4654:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4655:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

4657:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_test_local_min",NULL,NULL,&flg);
4658:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
4659:     /* Call converged reason views. This may involve user-provided viewers as well */
4660:     SNESConvergedReasonViewFromOptions(snes);

4662:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
4663:     if (snes->reason < 0) break;
4664:     if (grid <  snes->gridsequence) {
4665:       DM  fine;
4666:       Vec xnew;
4667:       Mat interp;

4669:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
4670:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
4671:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
4672:       DMCreateGlobalVector(fine,&xnew);
4673:       MatInterpolate(interp,x,xnew);
4674:       DMInterpolate(snes->dm,interp,fine);
4675:       MatDestroy(&interp);
4676:       x    = xnew;

4678:       SNESReset(snes);
4679:       SNESSetDM(snes,fine);
4680:       SNESResetFromOptions(snes);
4681:       DMDestroy(&fine);
4682:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
4683:     }
4684:   }
4685:   SNESViewFromOptions(snes,NULL,"-snes_view");
4686:   VecViewFromOptions(snes->vec_sol,(PetscObject)snes,"-snes_view_solution");
4687:   DMMonitor(snes->dm);

4689:   VecDestroy(&xcreated);
4690:   PetscObjectSAWsBlock((PetscObject)snes);
4691:   return(0);
4692: }

4694: /* --------- Internal routines for SNES Package --------- */

4696: /*@C
4697:    SNESSetType - Sets the method for the nonlinear solver.

4699:    Collective on SNES

4701:    Input Parameters:
4702: +  snes - the SNES context
4703: -  type - a known method

4705:    Options Database Key:
4706: .  -snes_type <type> - Sets the method; use -help for a list
4707:    of available methods (for instance, newtonls or newtontr)

4709:    Notes:
4710:    See "petsc/include/petscsnes.h" for available methods (for instance)
4711: +    SNESNEWTONLS - Newton's method with line search
4712:      (systems of nonlinear equations)
4713: -    SNESNEWTONTR - Newton's method with trust region
4714:      (systems of nonlinear equations)

4716:   Normally, it is best to use the SNESSetFromOptions() command and then
4717:   set the SNES solver type from the options database rather than by using
4718:   this routine.  Using the options database provides the user with
4719:   maximum flexibility in evaluating the many nonlinear solvers.
4720:   The SNESSetType() routine is provided for those situations where it
4721:   is necessary to set the nonlinear solver independently of the command
4722:   line or options database.  This might be the case, for example, when
4723:   the choice of solver changes during the execution of the program,
4724:   and the user's application is taking responsibility for choosing the
4725:   appropriate method.

4727:     Developer Notes:
4728:     SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
4729:     the constructor in that list and calls it to create the spexific object.

4731:   Level: intermediate

4733: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

4735: @*/
4736: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
4737: {
4738:   PetscErrorCode ierr,(*r)(SNES);
4739:   PetscBool      match;


4745:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
4746:   if (match) return(0);

4748:   PetscFunctionListFind(SNESList,type,&r);
4749:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
4750:   /* Destroy the previous private SNES context */
4751:   if (snes->ops->destroy) {
4752:     (*(snes)->ops->destroy)(snes);
4753:     snes->ops->destroy = NULL;
4754:   }
4755:   /* Reinitialize function pointers in SNESOps structure */
4756:   snes->ops->setup          = NULL;
4757:   snes->ops->solve          = NULL;
4758:   snes->ops->view           = NULL;
4759:   snes->ops->setfromoptions = NULL;
4760:   snes->ops->destroy        = NULL;

4762:   /* It may happen the user has customized the line search before calling SNESSetType */
4763:   if (((PetscObject)snes)->type_name) {
4764:     SNESLineSearchDestroy(&snes->linesearch);
4765:   }

4767:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4768:   snes->setupcalled = PETSC_FALSE;

4770:   PetscObjectChangeTypeName((PetscObject)snes,type);
4771:   (*r)(snes);
4772:   return(0);
4773: }

4775: /*@C
4776:    SNESGetType - Gets the SNES method type and name (as a string).

4778:    Not Collective

4780:    Input Parameter:
4781: .  snes - nonlinear solver context

4783:    Output Parameter:
4784: .  type - SNES method (a character string)

4786:    Level: intermediate

4788: @*/
4789: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
4790: {
4794:   *type = ((PetscObject)snes)->type_name;
4795:   return(0);
4796: }

4798: /*@
4799:   SNESSetSolution - Sets the solution vector for use by the SNES routines.

4801:   Logically Collective on SNES

4803:   Input Parameters:
4804: + snes - the SNES context obtained from SNESCreate()
4805: - u    - the solution vector

4807:   Level: beginner

4809: @*/
4810: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4811: {
4812:   DM             dm;

4818:   PetscObjectReference((PetscObject) u);
4819:   VecDestroy(&snes->vec_sol);

4821:   snes->vec_sol = u;

4823:   SNESGetDM(snes, &dm);
4824:   DMShellSetGlobalVector(dm, u);
4825:   return(0);
4826: }

4828: /*@
4829:    SNESGetSolution - Returns the vector where the approximate solution is
4830:    stored. This is the fine grid solution when using SNESSetGridSequence().

4832:    Not Collective, but Vec is parallel if SNES is parallel

4834:    Input Parameter:
4835: .  snes - the SNES context

4837:    Output Parameter:
4838: .  x - the solution

4840:    Level: intermediate

4842: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
4843: @*/
4844: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
4845: {
4849:   *x = snes->vec_sol;
4850:   return(0);
4851: }

4853: /*@
4854:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4855:    stored.

4857:    Not Collective, but Vec is parallel if SNES is parallel

4859:    Input Parameter:
4860: .  snes - the SNES context

4862:    Output Parameter:
4863: .  x - the solution update

4865:    Level: advanced

4867: .seealso: SNESGetSolution(), SNESGetFunction()
4868: @*/
4869: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4870: {
4874:   *x = snes->vec_sol_update;
4875:   return(0);
4876: }

4878: /*@C
4879:    SNESGetFunction - Returns the vector where the function is stored.

4881:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4883:    Input Parameter:
4884: .  snes - the SNES context

4886:    Output Parameter:
4887: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4888: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4889: -  ctx - the function context (or NULL if you don't want it)

4891:    Level: advanced

4893:     Notes: The vector r DOES NOT, in general contain the current value of the SNES nonlinear function

4895: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4896: @*/
4897: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4898: {
4900:   DM             dm;

4904:   if (r) {
4905:     if (!snes->vec_func) {
4906:       if (snes->vec_rhs) {
4907:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4908:       } else if (snes->vec_sol) {
4909:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4910:       } else if (snes->dm) {
4911:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4912:       }
4913:     }
4914:     *r = snes->vec_func;
4915:   }
4916:   SNESGetDM(snes,&dm);
4917:   DMSNESGetFunction(dm,f,ctx);
4918:   return(0);
4919: }

4921: /*@C
4922:    SNESGetNGS - Returns the NGS function and context.

4924:    Input Parameter:
4925: .  snes - the SNES context

4927:    Output Parameter:
4928: +  f - the function (or NULL) see SNESNGSFunction for details
4929: -  ctx    - the function context (or NULL)

4931:    Level: advanced

4933: .seealso: SNESSetNGS(), SNESGetFunction()
4934: @*/

4936: PetscErrorCode SNESGetNGS (SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void*), void ** ctx)
4937: {
4939:   DM             dm;

4943:   SNESGetDM(snes,&dm);
4944:   DMSNESGetNGS(dm,f,ctx);
4945:   return(0);
4946: }

4948: /*@C
4949:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4950:    SNES options in the database.

4952:    Logically Collective on SNES

4954:    Input Parameter:
4955: +  snes - the SNES context
4956: -  prefix - the prefix to prepend to all option names

4958:    Notes:
4959:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4960:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4962:    Level: advanced

4964: .seealso: SNESSetFromOptions()
4965: @*/
4966: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4967: {

4972:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4973:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4974:   if (snes->linesearch) {
4975:     SNESGetLineSearch(snes,&snes->linesearch);
4976:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4977:   }
4978:   KSPSetOptionsPrefix(snes->ksp,prefix);
4979:   return(0);
4980: }

4982: /*@C
4983:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4984:    SNES options in the database.

4986:    Logically Collective on SNES

4988:    Input Parameters:
4989: +  snes - the SNES context
4990: -  prefix - the prefix to prepend to all option names

4992:    Notes:
4993:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4994:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4996:    Level: advanced

4998: .seealso: SNESGetOptionsPrefix()
4999: @*/
5000: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
5001: {

5006:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
5007:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
5008:   if (snes->linesearch) {
5009:     SNESGetLineSearch(snes,&snes->linesearch);
5010:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
5011:   }
5012:   KSPAppendOptionsPrefix(snes->ksp,prefix);
5013:   return(0);
5014: }

5016: /*@C
5017:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
5018:    SNES options in the database.

5020:    Not Collective

5022:    Input Parameter:
5023: .  snes - the SNES context

5025:    Output Parameter:
5026: .  prefix - pointer to the prefix string used

5028:    Notes:
5029:     On the fortran side, the user should pass in a string 'prefix' of
5030:    sufficient length to hold the prefix.

5032:    Level: advanced

5034: .seealso: SNESAppendOptionsPrefix()
5035: @*/
5036: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
5037: {

5042:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
5043:   return(0);
5044: }


5047: /*@C
5048:   SNESRegister - Adds a method to the nonlinear solver package.

5050:    Not collective

5052:    Input Parameters:
5053: +  name_solver - name of a new user-defined solver
5054: -  routine_create - routine to create method context

5056:    Notes:
5057:    SNESRegister() may be called multiple times to add several user-defined solvers.

5059:    Sample usage:
5060: .vb
5061:    SNESRegister("my_solver",MySolverCreate);
5062: .ve

5064:    Then, your solver can be chosen with the procedural interface via
5065: $     SNESSetType(snes,"my_solver")
5066:    or at runtime via the option
5067: $     -snes_type my_solver

5069:    Level: advanced

5071:     Note: If your function is not being put into a shared library then use SNESRegister() instead

5073: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

5075:   Level: advanced
5076: @*/
5077: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
5078: {

5082:   SNESInitializePackage();
5083:   PetscFunctionListAdd(&SNESList,sname,function);
5084:   return(0);
5085: }

5087: PetscErrorCode  SNESTestLocalMin(SNES snes)
5088: {
5090:   PetscInt       N,i,j;
5091:   Vec            u,uh,fh;
5092:   PetscScalar    value;
5093:   PetscReal      norm;

5096:   SNESGetSolution(snes,&u);
5097:   VecDuplicate(u,&uh);
5098:   VecDuplicate(u,&fh);

5100:   /* currently only works for sequential */
5101:   PetscPrintf(PetscObjectComm((PetscObject)snes),"Testing FormFunction() for local min\n");
5102:   VecGetSize(u,&N);
5103:   for (i=0; i<N; i++) {
5104:     VecCopy(u,uh);
5105:     PetscPrintf(PetscObjectComm((PetscObject)snes),"i = %D\n",i);
5106:     for (j=-10; j<11; j++) {
5107:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
5108:       VecSetValue(uh,i,value,ADD_VALUES);
5109:       SNESComputeFunction(snes,uh,fh);
5110:       VecNorm(fh,NORM_2,&norm);
5111:       PetscPrintf(PetscObjectComm((PetscObject)snes),"       j norm %D %18.16e\n",j,norm);
5112:       value = -value;
5113:       VecSetValue(uh,i,value,ADD_VALUES);
5114:     }
5115:   }
5116:   VecDestroy(&uh);
5117:   VecDestroy(&fh);
5118:   return(0);
5119: }

5121: /*@
5122:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
5123:    computing relative tolerance for linear solvers within an inexact
5124:    Newton method.

5126:    Logically Collective on SNES

5128:    Input Parameters:
5129: +  snes - SNES context
5130: -  flag - PETSC_TRUE or PETSC_FALSE

5132:     Options Database:
5133: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5134: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
5135: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5136: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5137: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
5138: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
5139: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5140: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

5142:    Notes:
5143:    Currently, the default is to use a constant relative tolerance for
5144:    the inner linear solvers.  Alternatively, one can use the
5145:    Eisenstat-Walker method, where the relative convergence tolerance
5146:    is reset at each Newton iteration according progress of the nonlinear
5147:    solver.

5149:    Level: advanced

5151:    Reference:
5152:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5153:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

5155: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
5156: @*/
5157: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
5158: {
5162:   snes->ksp_ewconv = flag;
5163:   return(0);
5164: }

5166: /*@
5167:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
5168:    for computing relative tolerance for linear solvers within an
5169:    inexact Newton method.

5171:    Not Collective

5173:    Input Parameter:
5174: .  snes - SNES context

5176:    Output Parameter:
5177: .  flag - PETSC_TRUE or PETSC_FALSE

5179:    Notes:
5180:    Currently, the default is to use a constant relative tolerance for
5181:    the inner linear solvers.  Alternatively, one can use the
5182:    Eisenstat-Walker method, where the relative convergence tolerance
5183:    is reset at each Newton iteration according progress of the nonlinear
5184:    solver.

5186:    Level: advanced

5188:    Reference:
5189:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5190:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

5192: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
5193: @*/
5194: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
5195: {
5199:   *flag = snes->ksp_ewconv;
5200:   return(0);
5201: }

5203: /*@
5204:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5205:    convergence criteria for the linear solvers within an inexact
5206:    Newton method.

5208:    Logically Collective on SNES

5210:    Input Parameters:
5211: +    snes - SNES context
5212: .    version - version 1, 2 (default is 2) or 3
5213: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5214: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5215: .    gamma - multiplicative factor for version 2 rtol computation
5216:              (0 <= gamma2 <= 1)
5217: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
5218: .    alpha2 - power for safeguard
5219: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

5221:    Note:
5222:    Version 3 was contributed by Luis Chacon, June 2006.

5224:    Use PETSC_DEFAULT to retain the default for any of the parameters.

5226:    Level: advanced

5228:    Reference:
5229:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5230:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
5231:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

5233: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
5234: @*/
5235: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
5236: {
5237:   SNESKSPEW *kctx;

5241:   kctx = (SNESKSPEW*)snes->kspconvctx;
5242:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

5251:   if (version != PETSC_DEFAULT)   kctx->version   = version;
5252:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
5253:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
5254:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
5255:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
5256:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
5257:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

5259:   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);
5260:   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);
5261:   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);
5262:   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);
5263:   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);
5264:   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);
5265:   return(0);
5266: }

5268: /*@
5269:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5270:    convergence criteria for the linear solvers within an inexact
5271:    Newton method.

5273:    Not Collective

5275:    Input Parameters:
5276:      snes - SNES context

5278:    Output Parameters:
5279: +    version - version 1, 2 (default is 2) or 3
5280: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5281: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5282: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5283: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
5284: .    alpha2 - power for safeguard
5285: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

5287:    Level: advanced

5289: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
5290: @*/
5291: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
5292: {
5293:   SNESKSPEW *kctx;

5297:   kctx = (SNESKSPEW*)snes->kspconvctx;
5298:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
5299:   if (version)   *version   = kctx->version;
5300:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
5301:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
5302:   if (gamma)     *gamma     = kctx->gamma;
5303:   if (alpha)     *alpha     = kctx->alpha;
5304:   if (alpha2)    *alpha2    = kctx->alpha2;
5305:   if (threshold) *threshold = kctx->threshold;
5306:   return(0);
5307: }

5309:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5310: {
5312:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5313:   PetscReal      rtol  = PETSC_DEFAULT,stol;

5316:   if (!snes->ksp_ewconv) return(0);
5317:   if (!snes->iter) {
5318:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5319:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
5320:   }
5321:   else {
5322:     if (kctx->version == 1) {
5323:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
5324:       if (rtol < 0.0) rtol = -rtol;
5325:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
5326:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5327:     } else if (kctx->version == 2) {
5328:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5329:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
5330:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5331:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5332:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5333:       /* safeguard: avoid sharp decrease of rtol */
5334:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
5335:       stol = PetscMax(rtol,stol);
5336:       rtol = PetscMin(kctx->rtol_0,stol);
5337:       /* safeguard: avoid oversolving */
5338:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
5339:       stol = PetscMax(rtol,stol);
5340:       rtol = PetscMin(kctx->rtol_0,stol);
5341:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
5342:   }
5343:   /* safeguard: avoid rtol greater than one */
5344:   rtol = PetscMin(rtol,kctx->rtol_max);
5345:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
5346:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
5347:   return(0);
5348: }

5350: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5351: {
5353:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5354:   PCSide         pcside;
5355:   Vec            lres;

5358:   if (!snes->ksp_ewconv) return(0);
5359:   KSPGetTolerances(ksp,&kctx->rtol_last,NULL,NULL,NULL);
5360:   kctx->norm_last = snes->norm;
5361:   if (kctx->version == 1) {
5362:     PC        pc;
5363:     PetscBool isNone;

5365:     KSPGetPC(ksp, &pc);
5366:     PetscObjectTypeCompare((PetscObject) pc, PCNONE, &isNone);
5367:     KSPGetPCSide(ksp,&pcside);
5368:      if (pcside == PC_RIGHT || isNone) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
5369:       /* KSP residual is true linear residual */
5370:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
5371:     } else {
5372:       /* KSP residual is preconditioned residual */
5373:       /* compute true linear residual norm */
5374:       VecDuplicate(b,&lres);
5375:       MatMult(snes->jacobian,x,lres);
5376:       VecAYPX(lres,-1.0,b);
5377:       VecNorm(lres,NORM_2,&kctx->lresid_last);
5378:       VecDestroy(&lres);
5379:     }
5380:   }
5381:   return(0);
5382: }

5384: /*@
5385:    SNESGetKSP - Returns the KSP context for a SNES solver.

5387:    Not Collective, but if SNES object is parallel, then KSP object is parallel

5389:    Input Parameter:
5390: .  snes - the SNES context

5392:    Output Parameter:
5393: .  ksp - the KSP context

5395:    Notes:
5396:    The user can then directly manipulate the KSP context to set various
5397:    options, etc.  Likewise, the user can then extract and manipulate the
5398:    PC contexts as well.

5400:    Level: beginner

5402: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
5403: @*/
5404: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
5405: {


5412:   if (!snes->ksp) {
5413:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
5414:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
5415:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

5417:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
5418:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);

5420:     KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes);
5421:     PetscObjectSetOptions((PetscObject)snes->ksp,((PetscObject)snes)->options);
5422:   }
5423:   *ksp = snes->ksp;
5424:   return(0);
5425: }


5428: #include <petsc/private/dmimpl.h>
5429: /*@
5430:    SNESSetDM - Sets the DM that may be used by some nonlinear solvers or their underlying preconditioners

5432:    Logically Collective on SNES

5434:    Input Parameters:
5435: +  snes - the nonlinear solver context
5436: -  dm - the dm, cannot be NULL

5438:    Notes:
5439:    A DM can only be used for solving one problem at a time because information about the problem is stored on the DM,
5440:    even when not using interfaces like DMSNESSetFunction().  Use DMClone() to get a distinct DM when solving different
5441:    problems using the same function space.

5443:    Level: intermediate

5445: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
5446: @*/
5447: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
5448: {
5450:   KSP            ksp;
5451:   DMSNES         sdm;

5456:   PetscObjectReference((PetscObject)dm);
5457:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
5458:     if (snes->dm->dmsnes && !dm->dmsnes) {
5459:       DMCopyDMSNES(snes->dm,dm);
5460:       DMGetDMSNES(snes->dm,&sdm);
5461:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5462:     }
5463:     DMCoarsenHookRemove(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
5464:     DMDestroy(&snes->dm);
5465:   }
5466:   snes->dm     = dm;
5467:   snes->dmAuto = PETSC_FALSE;

5469:   SNESGetKSP(snes,&ksp);
5470:   KSPSetDM(ksp,dm);
5471:   KSPSetDMActive(ksp,PETSC_FALSE);
5472:   if (snes->npc) {
5473:     SNESSetDM(snes->npc, snes->dm);
5474:     SNESSetNPCSide(snes,snes->npcside);
5475:   }
5476:   return(0);
5477: }

5479: /*@
5480:    SNESGetDM - Gets the DM that may be used by some preconditioners

5482:    Not Collective but DM obtained is parallel on SNES

5484:    Input Parameter:
5485: . snes - the preconditioner context

5487:    Output Parameter:
5488: .  dm - the dm

5490:    Level: intermediate

5492: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
5493: @*/
5494: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
5495: {

5500:   if (!snes->dm) {
5501:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
5502:     snes->dmAuto = PETSC_TRUE;
5503:   }
5504:   *dm = snes->dm;
5505:   return(0);
5506: }

5508: /*@
5509:   SNESSetNPC - Sets the nonlinear preconditioner to be used.

5511:   Collective on SNES

5513:   Input Parameters:
5514: + snes - iterative context obtained from SNESCreate()
5515: - pc   - the preconditioner object

5517:   Notes:
5518:   Use SNESGetNPC() to retrieve the preconditioner context (for example,
5519:   to configure it using the API).

5521:   Level: developer

5523: .seealso: SNESGetNPC(), SNESHasNPC()
5524: @*/
5525: PetscErrorCode SNESSetNPC(SNES snes, SNES pc)
5526: {

5533:   PetscObjectReference((PetscObject) pc);
5534:   SNESDestroy(&snes->npc);
5535:   snes->npc = pc;
5536:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->npc);
5537:   return(0);
5538: }

5540: /*@
5541:   SNESGetNPC - Creates a nonlinear preconditioning solver (SNES) to be used to precondition the nonlinear solver.

5543:   Not Collective; but any changes to the obtained SNES object must be applied collectively

5545:   Input Parameter:
5546: . snes - iterative context obtained from SNESCreate()

5548:   Output Parameter:
5549: . pc - preconditioner context

5551:   Options Database:
5552: . -npc_snes_type <type> - set the type of the SNES to use as the nonlinear preconditioner

5554:   Notes:
5555:     If a SNES was previously set with SNESSetNPC() then that SNES is returned, otherwise a new SNES object is created.

5557:     The (preconditioner) SNES returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5558:     SNES during SNESSetUp()

5560:   Level: developer

5562: .seealso: SNESSetNPC(), SNESHasNPC(), SNES, SNESCreate()
5563: @*/
5564: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5565: {
5567:   const char     *optionsprefix;

5572:   if (!snes->npc) {
5573:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->npc);
5574:     PetscObjectIncrementTabLevel((PetscObject)snes->npc,(PetscObject)snes,1);
5575:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->npc);
5576:     SNESGetOptionsPrefix(snes,&optionsprefix);
5577:     SNESSetOptionsPrefix(snes->npc,optionsprefix);
5578:     SNESAppendOptionsPrefix(snes->npc,"npc_");
5579:     SNESSetCountersReset(snes->npc,PETSC_FALSE);
5580:   }
5581:   *pc = snes->npc;
5582:   return(0);
5583: }

5585: /*@
5586:   SNESHasNPC - Returns whether a nonlinear preconditioner exists

5588:   Not Collective

5590:   Input Parameter:
5591: . snes - iterative context obtained from SNESCreate()

5593:   Output Parameter:
5594: . has_npc - whether the SNES has an NPC or not

5596:   Level: developer

5598: .seealso: SNESSetNPC(), SNESGetNPC()
5599: @*/
5600: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5601: {
5604:   *has_npc = (PetscBool) (snes->npc ? PETSC_TRUE : PETSC_FALSE);
5605:   return(0);
5606: }

5608: /*@
5609:     SNESSetNPCSide - Sets the preconditioning side.

5611:     Logically Collective on SNES

5613:     Input Parameter:
5614: .   snes - iterative context obtained from SNESCreate()

5616:     Output Parameter:
5617: .   side - the preconditioning side, where side is one of
5618: .vb
5619:       PC_LEFT - left preconditioning
5620:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5621: .ve

5623:     Options Database Keys:
5624: .   -snes_pc_side <right,left>

5626:     Notes:
5627:     SNESNRICHARDSON and SNESNCG only support left preconditioning.

5629:     Level: intermediate

5631: .seealso: SNESGetNPCSide(), KSPSetPCSide()
5632: @*/
5633: PetscErrorCode  SNESSetNPCSide(SNES snes,PCSide side)
5634: {
5638:   snes->npcside= side;
5639:   return(0);
5640: }

5642: /*@
5643:     SNESGetNPCSide - Gets the preconditioning side.

5645:     Not Collective

5647:     Input Parameter:
5648: .   snes - iterative context obtained from SNESCreate()

5650:     Output Parameter:
5651: .   side - the preconditioning side, where side is one of
5652: .vb
5653:       PC_LEFT - left preconditioning
5654:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5655: .ve

5657:     Level: intermediate

5659: .seealso: SNESSetNPCSide(), KSPGetPCSide()
5660: @*/
5661: PetscErrorCode  SNESGetNPCSide(SNES snes,PCSide *side)
5662: {
5666:   *side = snes->npcside;
5667:   return(0);
5668: }

5670: /*@
5671:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

5673:   Collective on SNES

5675:   Input Parameters:
5676: + snes - iterative context obtained from SNESCreate()
5677: - linesearch   - the linesearch object

5679:   Notes:
5680:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
5681:   to configure it using the API).

5683:   Level: developer

5685: .seealso: SNESGetLineSearch()
5686: @*/
5687: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5688: {

5695:   PetscObjectReference((PetscObject) linesearch);
5696:   SNESLineSearchDestroy(&snes->linesearch);

5698:   snes->linesearch = linesearch;

5700:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5701:   return(0);
5702: }

5704: /*@
5705:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
5706:   or creates a default line search instance associated with the SNES and returns it.

5708:   Not Collective

5710:   Input Parameter:
5711: . snes - iterative context obtained from SNESCreate()

5713:   Output Parameter:
5714: . linesearch - linesearch context

5716:   Level: beginner

5718: .seealso: SNESSetLineSearch(), SNESLineSearchCreate()
5719: @*/
5720: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5721: {
5723:   const char     *optionsprefix;

5728:   if (!snes->linesearch) {
5729:     SNESGetOptionsPrefix(snes, &optionsprefix);
5730:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
5731:     SNESLineSearchSetSNES(snes->linesearch, snes);
5732:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
5733:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
5734:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5735:   }
5736:   *linesearch = snes->linesearch;
5737:   return(0);
5738: }