Actual source code: snes.c

petsc-3.15.0 2021-04-05
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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 available formats include
357: +     PETSC_VIEWER_DEFAULT - standard output (default)
358: -     PETSC_VIEWER_ASCII_INFO_DETAIL - more verbose output for SNESNASM

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

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

365:    Level: beginner

367: .seealso: PetscViewerASCIIOpen()
368: @*/
369: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
370: {
371:   SNESKSPEW      *kctx;
373:   KSP            ksp;
374:   SNESLineSearch linesearch;
375:   PetscBool      iascii,isstring,isbinary,isdraw;
376:   DMSNES         dmsnes;
377: #if defined(PETSC_HAVE_SAWS)
378:   PetscBool      issaws;
379: #endif

383:   if (!viewer) {
384:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&viewer);
385:   }

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

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

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

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

504:     PetscObjectGetName((PetscObject)snes,&name);
505:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
506:     if (!((PetscObject)snes)->amsmem && !rank) {
507:       char       dir[1024];

509:       PetscObjectViewSAWs((PetscObject)snes,viewer);
510:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
511:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
512:       if (!snes->conv_hist) {
513:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
514:       }
515:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
516:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
517:     }
518: #endif
519:   }
520:   if (snes->linesearch) {
521:     SNESGetLineSearch(snes, &linesearch);
522:     PetscViewerASCIIPushTab(viewer);
523:     SNESLineSearchView(linesearch, viewer);
524:     PetscViewerASCIIPopTab(viewer);
525:   }
526:   if (snes->npc && snes->usesnpc) {
527:     PetscViewerASCIIPushTab(viewer);
528:     SNESView(snes->npc, viewer);
529:     PetscViewerASCIIPopTab(viewer);
530:   }
531:   PetscViewerASCIIPushTab(viewer);
532:   DMGetDMSNES(snes->dm,&dmsnes);
533:   DMSNESView(dmsnes, viewer);
534:   PetscViewerASCIIPopTab(viewer);
535:   if (snes->usesksp) {
536:     SNESGetKSP(snes,&ksp);
537:     PetscViewerASCIIPushTab(viewer);
538:     KSPView(ksp,viewer);
539:     PetscViewerASCIIPopTab(viewer);
540:   }
541:   if (isdraw) {
542:     PetscDraw draw;
543:     PetscViewerDrawGetDraw(viewer,0,&draw);
544:     PetscDrawPopCurrentPoint(draw);
545:   }
546:   return(0);
547: }

549: /*
550:   We retain a list of functions that also take SNES command
551:   line options. These are called at the end SNESSetFromOptions()
552: */
553: #define MAXSETFROMOPTIONS 5
554: static PetscInt numberofsetfromoptions;
555: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

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

560:   Not Collective

562:   Input Parameter:
563: . snescheck - function that checks for options

565:   Level: developer

567: .seealso: SNESSetFromOptions()
568: @*/
569: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
570: {
572:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
573:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
574:   return(0);
575: }

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

579: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
580: {
581:   Mat            J;
583:   MatNullSpace   nullsp;


588:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
589:     Mat A = snes->jacobian, B = snes->jacobian_pre;
590:     MatCreateVecs(A ? A : B, NULL,&snes->vec_func);
591:   }

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

606:   /* attach any user provided null space that was on Amat to the newly created matrix free matrix */
607:   if (snes->jacobian) {
608:     MatGetNullSpace(snes->jacobian,&nullsp);
609:     if (nullsp) {
610:       MatSetNullSpace(J,nullsp);
611:     }
612:   }

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

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

630:       SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,NULL);
631:       /* Force no preconditioner */
632:       SNESGetKSP(snes,&ksp);
633:       KSPGetPC(ksp,&pc);
634:       PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&match);
635:       if (!match) {
636:         PetscInfo(snes,"Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n");
637:         PCSetType(pc,PCNONE);
638:       }
639:     }
640:   }
641:   MatDestroy(&J);
642:   return(0);
643: }

645: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
646: {
647:   SNES           snes = (SNES)ctx;
649:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

652:   if (PetscLogPrintInfo) {
653:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
654:     DMGetRefineLevel(dmfine,&finelevel);
655:     DMGetCoarsenLevel(dmfine,&fineclevel);
656:     DMGetRefineLevel(dmcoarse,&coarselevel);
657:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
658:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
659:   }
660:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
661:   else {
662:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
663:     Xfine = Xfine_named;
664:   }
665:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
666:   if (Inject) {
667:     MatRestrict(Inject,Xfine,Xcoarse);
668:   } else {
669:     MatRestrict(Restrict,Xfine,Xcoarse);
670:     VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
671:   }
672:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
673:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
674:   return(0);
675: }

677: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
678: {

682:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
683:   return(0);
684: }

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

698:   dmsave = snes->dm;
699:   KSPGetDM(ksp,&snes->dm);
700:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
701:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
702:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
703:     X    = Xnamed;
704:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
705:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
706:     if (jac == SNESComputeJacobianDefaultColor) {
707:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,NULL);
708:     }
709:   }
710:   /* Make sure KSP DM has the Jacobian computation routine */
711:   {
712:     DMSNES sdm;

714:     DMGetDMSNES(snes->dm, &sdm);
715:     if (!sdm->ops->computejacobian) {
716:       DMCopyDMSNES(dmsave, snes->dm);
717:     }
718:   }
719:   /* Compute the operators */
720:   SNESComputeJacobian(snes,X,A,B);
721:   /* Put the previous context back */
722:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
723:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
724:   }

726:   if (Xnamed) {DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);}
727:   snes->dm = dmsave;
728:   return(0);
729: }

731: /*@
732:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

734:    Collective

736:    Input Arguments:
737: .  snes - snes to configure

739:    Level: developer

741: .seealso: SNESSetUp()
742: @*/
743: PetscErrorCode SNESSetUpMatrices(SNES snes)
744: {
746:   DM             dm;
747:   DMSNES         sdm;

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

776:     J    = snes->jacobian;
777:     DMGetDS(dm, &prob);
778:     if (prob) {PetscDSHasJacobianPreconditioner(prob, &hasPrec);}
779:     if (J)            {PetscObjectReference((PetscObject) J);}
780:     else if (hasPrec) {DMCreateMatrix(snes->dm, &J);}
781:     DMCreateMatrix(snes->dm, &B);
782:     SNESSetJacobian(snes, J ? J : B, B, NULL, NULL);
783:     MatDestroy(&J);
784:     MatDestroy(&B);
785:   }
786:   {
787:     KSP ksp;
788:     SNESGetKSP(snes,&ksp);
789:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
790:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
791:   }
792:   return(0);
793: }

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

798:    Collective on SNES

800:    Input Parameters:
801: +  snes - SNES object you wish to monitor
802: .  name - the monitor type one is seeking
803: .  help - message indicating what monitoring is done
804: .  manual - manual page for the monitor
805: .  monitor - the monitor function
806: -  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

808:    Level: developer

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

826:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,name,&viewer,&format,&flg);
827:   if (flg) {
828:     PetscViewerAndFormat *vf;
829:     PetscViewerAndFormatCreate(viewer,format,&vf);
830:     PetscObjectDereference((PetscObject)viewer);
831:     if (monitorsetup) {
832:       (*monitorsetup)(snes,vf);
833:     }
834:     SNESMonitorSet(snes,(PetscErrorCode (*)(SNES,PetscInt,PetscReal,void*))monitor,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);
835:   }
836:   return(0);
837: }

839: /*@
840:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

842:    Collective on SNES

844:    Input Parameter:
845: .  snes - the SNES context

847:    Options Database Keys:
848: +  -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, SNESType for complete list
849: .  -snes_stol - convergence tolerance in terms of the norm
850:                 of the change in the solution between steps
851: .  -snes_atol <abstol> - absolute tolerance of residual norm
852: .  -snes_rtol <rtol> - relative decrease in tolerance norm from initial
853: .  -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
854: .  -snes_force_iteration <force> - force SNESSolve() to take at least one iteration
855: .  -snes_max_it <max_it> - maximum number of iterations
856: .  -snes_max_funcs <max_funcs> - maximum number of function evaluations
857: .  -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
858: .  -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
859: .  -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
860: .  -snes_lag_preconditioner_persists <true,false> - retains the -snes_lag_preconditioner information across multiple SNESSolve()
861: .  -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
862: .  -snes_lag_jacobian_persists <true,false> - retains the -snes_lag_jacobian information across multiple SNESSolve()
863: .  -snes_trtol <trtol> - trust region tolerance
864: .  -snes_no_convergence_test - skip convergence test in nonlinear
865:                                solver; hence iterations will continue until max_it
866:                                or some other criterion is reached. Saves expense
867:                                of convergence test
868: .  -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
869: .  -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
870: .  -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
871: .  -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
872: .  -snes_monitor_lg_residualnorm - plots residual norm at each iteration
873: .  -snes_monitor_lg_range - plots residual norm at each iteration
874: .  -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
875: .  -snes_fd_color - use finite differences with coloring to compute Jacobian
876: .  -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
877: .  -snes_converged_reason - print the reason for convergence/divergence after each solve
878: .  -npc_snes_type <type> - the SNES type to use as a nonlinear preconditioner
879: .   -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.
880: -   -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.

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

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

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

899:    Level: beginner

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

917:   SNESRegisterAll();
918:   PetscObjectOptionsBegin((PetscObject)snes);
919:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
920:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
921:   if (flg) {
922:     SNESSetType(snes,type);
923:   } else if (!((PetscObject)snes)->type_name) {
924:     SNESSetType(snes,deft);
925:   }
926:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,NULL);
927:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,NULL);

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

939:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
940:   if (flg) {
941:     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");
942:     SNESSetLagPreconditioner(snes,lag);
943:   }
944:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple SNES solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
945:   if (flg) {
946:     SNESSetLagPreconditionerPersists(snes,persist);
947:   }
948:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
949:   if (flg) {
950:     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");
951:     SNESSetLagJacobian(snes,lag);
952:   }
953:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple SNES solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
954:   if (flg) {
955:     SNESSetLagJacobianPersists(snes,persist);
956:   }

958:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
959:   if (flg) {
960:     SNESSetGridSequence(snes,grids);
961:   }

963:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,sizeof(convtests)/sizeof(char*),"default",&indx,&flg);
964:   if (flg) {
965:     switch (indx) {
966:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
967:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL); break;
968:     case 2: SNESSetConvergenceTest(snes,SNESConvergedCorrectPressure,NULL,NULL); break;
969:     }
970:   }

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

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

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

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

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

990:   flg  = PETSC_FALSE;
991:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,&set);
992:   if (set && flg) {SNESMonitorCancel(snes);}

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

998:   SNESMonitorSetFromOptions(snes,"-snes_monitor_ratio","Monitor ratios of the norm of function for consecutive steps","SNESMonitorRatio",SNESMonitorRatio,SNESMonitorRatioSetUp);
999:   SNESMonitorSetFromOptions(snes,"-snes_monitor_field","Monitor norm of function (split into fields)","SNESMonitorDefaultField",SNESMonitorDefaultField,NULL);
1000:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution","View solution at each iteration","SNESMonitorSolution",SNESMonitorSolution,NULL);
1001:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution_update","View correction at each iteration","SNESMonitorSolutionUpdate",SNESMonitorSolutionUpdate,NULL);
1002:   SNESMonitorSetFromOptions(snes,"-snes_monitor_residual","View residual at each iteration","SNESMonitorResidual",SNESMonitorResidual,NULL);
1003:   SNESMonitorSetFromOptions(snes,"-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",SNESMonitorJacUpdateSpectrum,NULL);
1004:   SNESMonitorSetFromOptions(snes,"-snes_monitor_fields","Monitor norm of function per field","SNESMonitorSet",SNESMonitorFields,NULL);

1006:   PetscOptionsString("-snes_monitor_python","Use Python function","SNESMonitorSet",NULL,monfilename,sizeof(monfilename),&flg);
1007:   if (flg) {PetscPythonMonitorSet((PetscObject)snes,monfilename);}

1009:   flg  = PETSC_FALSE;
1010:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
1011:   if (flg) {
1012:     PetscViewer ctx;

1014:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
1015:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
1016:   }

1018:   flg  = PETSC_FALSE;
1019:   PetscOptionsBool("-snes_converged_reason_view_cancel","Remove all converged reason viewers","SNESConvergedReasonViewCancel",flg,&flg,&set);
1020:   if (set && flg) {SNESConvergedReasonViewCancel(snes);}

1022:   flg  = PETSC_FALSE;
1023:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
1024:   if (flg) {
1025:     void    *functx;
1026:     DM      dm;
1027:     DMSNES  sdm;
1028:     SNESGetDM(snes,&dm);
1029:     DMGetDMSNES(dm,&sdm);
1030:     sdm->jacobianctx = NULL;
1031:     SNESGetFunction(snes,NULL,NULL,&functx);
1032:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
1033:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
1034:   }

1036:   flg  = PETSC_FALSE;
1037:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
1038:   if (flg) {
1039:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
1040:   }

1042:   flg  = PETSC_FALSE;
1043:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
1044:   if (flg) {
1045:     DM             dm;
1046:     DMSNES         sdm;
1047:     SNESGetDM(snes,&dm);
1048:     DMGetDMSNES(dm,&sdm);
1049:     sdm->jacobianctx = NULL;
1050:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,NULL);
1051:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
1052:   }

1054:   flg  = PETSC_FALSE;
1055:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf_operator,&flg);
1056:   if (flg && snes->mf_operator) {
1057:     snes->mf_operator = PETSC_TRUE;
1058:     snes->mf          = PETSC_TRUE;
1059:   }
1060:   flg  = PETSC_FALSE;
1061:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf,&flg);
1062:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1063:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,NULL);

1065:   flg  = PETSC_FALSE;
1066:   SNESGetNPCSide(snes,&pcside);
1067:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetNPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
1068:   if (flg) {SNESSetNPCSide(snes,pcside);}

1070: #if defined(PETSC_HAVE_SAWS)
1071:   /*
1072:     Publish convergence information using SAWs
1073:   */
1074:   flg  = PETSC_FALSE;
1075:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
1076:   if (flg) {
1077:     void *ctx;
1078:     SNESMonitorSAWsCreate(snes,&ctx);
1079:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
1080:   }
1081: #endif
1082: #if defined(PETSC_HAVE_SAWS)
1083:   {
1084:   PetscBool set;
1085:   flg  = PETSC_FALSE;
1086:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
1087:   if (set) {
1088:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
1089:   }
1090:   }
1091: #endif

1093:   for (i = 0; i < numberofsetfromoptions; i++) {
1094:     (*othersetfromoptions[i])(snes);
1095:   }

1097:   if (snes->ops->setfromoptions) {
1098:     (*snes->ops->setfromoptions)(PetscOptionsObject,snes);
1099:   }

1101:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
1102:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)snes);
1103:   PetscOptionsEnd();

1105:   if (snes->linesearch) {
1106:     SNESGetLineSearch(snes, &snes->linesearch);
1107:     SNESLineSearchSetFromOptions(snes->linesearch);
1108:   }

1110:   if (snes->usesksp) {
1111:     if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
1112:     KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
1113:     KSPSetFromOptions(snes->ksp);
1114:   }

1116:   /* if user has set the SNES NPC type via options database, create it. */
1117:   SNESGetOptionsPrefix(snes, &optionsprefix);
1118:   PetscOptionsHasName(((PetscObject)snes)->options,optionsprefix, "-npc_snes_type", &pcset);
1119:   if (pcset && (!snes->npc)) {
1120:     SNESGetNPC(snes, &snes->npc);
1121:   }
1122:   if (snes->npc) {
1123:     SNESSetFromOptions(snes->npc);
1124:   }
1125:   snes->setfromoptionscalled++;
1126:   return(0);
1127: }

1129: /*@
1130:    SNESResetFromOptions - Sets various SNES and KSP parameters from user options ONLY if the SNES was previously set from options

1132:    Collective on SNES

1134:    Input Parameter:
1135: .  snes - the SNES context

1137:    Level: beginner

1139: .seealso: SNESSetFromOptions(), SNESSetOptionsPrefix()
1140: @*/
1141: PetscErrorCode SNESResetFromOptions(SNES snes)
1142: {

1146:   if (snes->setfromoptionscalled) {SNESSetFromOptions(snes);}
1147:   return(0);
1148: }

1150: /*@C
1151:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1152:    the nonlinear solvers.

1154:    Logically Collective on SNES

1156:    Input Parameters:
1157: +  snes - the SNES context
1158: .  compute - function to compute the context
1159: -  destroy - function to destroy the context

1161:    Level: intermediate

1163:    Notes:
1164:    This function is currently not available from Fortran.

1166: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
1167: @*/
1168: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
1169: {
1172:   snes->ops->usercompute = compute;
1173:   snes->ops->userdestroy = destroy;
1174:   return(0);
1175: }

1177: /*@
1178:    SNESSetApplicationContext - Sets the optional user-defined context for
1179:    the nonlinear solvers.

1181:    Logically Collective on SNES

1183:    Input Parameters:
1184: +  snes - the SNES context
1185: -  usrP - optional user context

1187:    Level: intermediate

1189:    Fortran Notes:
1190:     To use this from Fortran you must write a Fortran interface definition for this
1191:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1193: .seealso: SNESGetApplicationContext()
1194: @*/
1195: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
1196: {
1198:   KSP            ksp;

1202:   SNESGetKSP(snes,&ksp);
1203:   KSPSetApplicationContext(ksp,usrP);
1204:   snes->user = usrP;
1205:   return(0);
1206: }

1208: /*@
1209:    SNESGetApplicationContext - Gets the user-defined context for the
1210:    nonlinear solvers.

1212:    Not Collective

1214:    Input Parameter:
1215: .  snes - SNES context

1217:    Output Parameter:
1218: .  usrP - user context

1220:    Fortran Notes:
1221:     To use this from Fortran you must write a Fortran interface definition for this
1222:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1224:    Level: intermediate

1226: .seealso: SNESSetApplicationContext()
1227: @*/
1228: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
1229: {
1232:   *(void**)usrP = snes->user;
1233:   return(0);
1234: }

1236: /*@
1237:    SNESSetUseMatrixFree - indicates that SNES should use matrix free finite difference matrix vector products internally to apply the Jacobian.

1239:    Collective on SNES

1241:    Input Parameters:
1242: +  snes - SNES context
1243: .  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used
1244: -  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored

1246:    Options Database:
1247: + -snes_mf - use matrix free for both the mat and pmat operator
1248: . -snes_mf_operator - use matrix free only for the mat operator
1249: . -snes_fd_color - compute the Jacobian via coloring and finite differences.
1250: - -snes_fd - compute the Jacobian via finite differences (slow)

1252:    Level: intermediate

1254:    Notes:
1255:       SNES supports three approaches for computing (approximate) Jacobians: user provided via SNESSetJacobian(), matrix free, and computing explictly with
1256:       finite differences and coloring using MatFDColoring. It is also possible to use automatic differentiation and the MatFDColoring object.

1258: .seealso:   SNESGetUseMatrixFree(), MatCreateSNESMF(), SNESComputeJacobianDefaultColor()
1259: @*/
1260: PetscErrorCode  SNESSetUseMatrixFree(SNES snes,PetscBool mf_operator,PetscBool mf)
1261: {
1266:   snes->mf          = mf_operator ? PETSC_TRUE : mf;
1267:   snes->mf_operator = mf_operator;
1268:   return(0);
1269: }

1271: /*@
1272:    SNESGetUseMatrixFree - indicates if the SNES uses matrix free finite difference matrix vector products to apply the Jacobian.

1274:    Collective on SNES

1276:    Input Parameter:
1277: .  snes - SNES context

1279:    Output Parameters:
1280: +  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used
1281: -  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored

1283:    Options Database:
1284: + -snes_mf - use matrix free for both the mat and pmat operator
1285: - -snes_mf_operator - use matrix free only for the mat operator

1287:    Level: intermediate

1289: .seealso:   SNESSetUseMatrixFree(), MatCreateSNESMF()
1290: @*/
1291: PetscErrorCode  SNESGetUseMatrixFree(SNES snes,PetscBool *mf_operator,PetscBool *mf)
1292: {
1295:   if (mf)          *mf          = snes->mf;
1296:   if (mf_operator) *mf_operator = snes->mf_operator;
1297:   return(0);
1298: }

1300: /*@
1301:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1302:    at this time.

1304:    Not Collective

1306:    Input Parameter:
1307: .  snes - SNES context

1309:    Output Parameter:
1310: .  iter - iteration number

1312:    Notes:
1313:    For example, during the computation of iteration 2 this would return 1.

1315:    This is useful for using lagged Jacobians (where one does not recompute the
1316:    Jacobian at each SNES iteration). For example, the code
1317: .vb
1318:       SNESGetIterationNumber(snes,&it);
1319:       if (!(it % 2)) {
1320:         [compute Jacobian here]
1321:       }
1322: .ve
1323:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1324:    recomputed every second SNES iteration.

1326:    After the SNES solve is complete this will return the number of nonlinear iterations used.

1328:    Level: intermediate

1330: .seealso:   SNESGetLinearSolveIterations()
1331: @*/
1332: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1333: {
1337:   *iter = snes->iter;
1338:   return(0);
1339: }

1341: /*@
1342:    SNESSetIterationNumber - Sets the current iteration number.

1344:    Not Collective

1346:    Input Parameter:
1347: +  snes - SNES context
1348: -  iter - iteration number

1350:    Level: developer

1352: .seealso:   SNESGetLinearSolveIterations()
1353: @*/
1354: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1355: {

1360:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1361:   snes->iter = iter;
1362:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1363:   return(0);
1364: }

1366: /*@
1367:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1368:    attempted by the nonlinear solver.

1370:    Not Collective

1372:    Input Parameter:
1373: .  snes - SNES context

1375:    Output Parameter:
1376: .  nfails - number of unsuccessful steps attempted

1378:    Notes:
1379:    This counter is reset to zero for each successive call to SNESSolve().

1381:    Level: intermediate

1383: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1384:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1385: @*/
1386: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1387: {
1391:   *nfails = snes->numFailures;
1392:   return(0);
1393: }

1395: /*@
1396:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1397:    attempted by the nonlinear solver before it gives up.

1399:    Not Collective

1401:    Input Parameters:
1402: +  snes     - SNES context
1403: -  maxFails - maximum of unsuccessful steps

1405:    Level: intermediate

1407: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1408:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1409: @*/
1410: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1411: {
1414:   snes->maxFailures = maxFails;
1415:   return(0);
1416: }

1418: /*@
1419:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1420:    attempted by the nonlinear solver before it gives up.

1422:    Not Collective

1424:    Input Parameter:
1425: .  snes     - SNES context

1427:    Output Parameter:
1428: .  maxFails - maximum of unsuccessful steps

1430:    Level: intermediate

1432: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1433:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1435: @*/
1436: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1437: {
1441:   *maxFails = snes->maxFailures;
1442:   return(0);
1443: }

1445: /*@
1446:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1447:      done by SNES.

1449:    Not Collective

1451:    Input Parameter:
1452: .  snes     - SNES context

1454:    Output Parameter:
1455: .  nfuncs - number of evaluations

1457:    Level: intermediate

1459:    Notes:
1460:     Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1462: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1463: @*/
1464: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1465: {
1469:   *nfuncs = snes->nfuncs;
1470:   return(0);
1471: }

1473: /*@
1474:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1475:    linear solvers.

1477:    Not Collective

1479:    Input Parameter:
1480: .  snes - SNES context

1482:    Output Parameter:
1483: .  nfails - number of failed solves

1485:    Level: intermediate

1487:    Options Database Keys:
1488: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1490:    Notes:
1491:    This counter is reset to zero for each successive call to SNESSolve().

1493: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1494: @*/
1495: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1496: {
1500:   *nfails = snes->numLinearSolveFailures;
1501:   return(0);
1502: }

1504: /*@
1505:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1506:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1508:    Logically Collective on SNES

1510:    Input Parameters:
1511: +  snes     - SNES context
1512: -  maxFails - maximum allowed linear solve failures

1514:    Level: intermediate

1516:    Options Database Keys:
1517: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1519:    Notes:
1520:     By default this is 0; that is SNES returns on the first failed linear solve

1522: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations()
1523: @*/
1524: PetscErrorCode  SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1525: {
1529:   snes->maxLinearSolveFailures = maxFails;
1530:   return(0);
1531: }

1533: /*@
1534:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1535:      are allowed before SNES terminates

1537:    Not Collective

1539:    Input Parameter:
1540: .  snes     - SNES context

1542:    Output Parameter:
1543: .  maxFails - maximum of unsuccessful solves allowed

1545:    Level: intermediate

1547:    Notes:
1548:     By default this is 1; that is SNES returns on the first failed linear solve

1550: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1551: @*/
1552: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1553: {
1557:   *maxFails = snes->maxLinearSolveFailures;
1558:   return(0);
1559: }

1561: /*@
1562:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1563:    used by the nonlinear solver.

1565:    Not Collective

1567:    Input Parameter:
1568: .  snes - SNES context

1570:    Output Parameter:
1571: .  lits - number of linear iterations

1573:    Notes:
1574:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1576:    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
1577:    then call KSPGetIterationNumber() after the failed solve.

1579:    Level: intermediate

1581: .seealso:  SNESGetIterationNumber(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1582: @*/
1583: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1584: {
1588:   *lits = snes->linear_its;
1589:   return(0);
1590: }

1592: /*@
1593:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1594:    are reset every time SNESSolve() is called.

1596:    Logically Collective on SNES

1598:    Input Parameter:
1599: +  snes - SNES context
1600: -  reset - whether to reset the counters or not

1602:    Notes:
1603:    This defaults to PETSC_TRUE

1605:    Level: developer

1607: .seealso:  SNESGetNumberFunctionEvals(), SNESGetLinearSolveIterations(), SNESGetNPC()
1608: @*/
1609: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1610: {
1614:   snes->counters_reset = reset;
1615:   return(0);
1616: }


1619: /*@
1620:    SNESSetKSP - Sets a KSP context for the SNES object to use

1622:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1624:    Input Parameters:
1625: +  snes - the SNES context
1626: -  ksp - the KSP context

1628:    Notes:
1629:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1630:    so this routine is rarely needed.

1632:    The KSP object that is already in the SNES object has its reference count
1633:    decreased by one.

1635:    Level: developer

1637: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1638: @*/
1639: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1640: {

1647:   PetscObjectReference((PetscObject)ksp);
1648:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1649:   snes->ksp = ksp;
1650:   return(0);
1651: }

1653: /* -----------------------------------------------------------*/
1654: /*@
1655:    SNESCreate - Creates a nonlinear solver context.

1657:    Collective

1659:    Input Parameters:
1660: .  comm - MPI communicator

1662:    Output Parameter:
1663: .  outsnes - the new SNES context

1665:    Options Database Keys:
1666: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1667:                and no preconditioning matrix
1668: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1669:                products, and a user-provided preconditioning matrix
1670:                as set by SNESSetJacobian()
1671: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1673:    Level: beginner

1675:    Developer Notes:
1676:     SNES always creates a KSP object even though many SNES methods do not use it. This is
1677:                     unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1678:                     particular method does use KSP and regulates if the information about the KSP is printed
1679:                     in SNESView(). TSSetFromOptions() does call SNESSetFromOptions() which can lead to users being confused
1680:                     by help messages about meaningless SNES options.

1682:                     SNES always creates the snes->kspconvctx even though it is used by only one type. This should
1683:                     be fixed.

1685: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner(), SNESSetLagJacobian()

1687: @*/
1688: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1689: {
1691:   SNES           snes;
1692:   SNESKSPEW      *kctx;

1696:   *outsnes = NULL;
1697:   SNESInitializePackage();

1699:   PetscHeaderCreate(snes,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1701:   snes->ops->converged    = SNESConvergedDefault;
1702:   snes->usesksp           = PETSC_TRUE;
1703:   snes->tolerancesset     = PETSC_FALSE;
1704:   snes->max_its           = 50;
1705:   snes->max_funcs         = 10000;
1706:   snes->norm              = 0.0;
1707:   snes->xnorm             = 0.0;
1708:   snes->ynorm             = 0.0;
1709:   snes->normschedule      = SNES_NORM_ALWAYS;
1710:   snes->functype          = SNES_FUNCTION_DEFAULT;
1711: #if defined(PETSC_USE_REAL_SINGLE)
1712:   snes->rtol              = 1.e-5;
1713: #else
1714:   snes->rtol              = 1.e-8;
1715: #endif
1716:   snes->ttol              = 0.0;
1717: #if defined(PETSC_USE_REAL_SINGLE)
1718:   snes->abstol            = 1.e-25;
1719: #else
1720:   snes->abstol            = 1.e-50;
1721: #endif
1722: #if defined(PETSC_USE_REAL_SINGLE)
1723:   snes->stol              = 1.e-5;
1724: #else
1725:   snes->stol              = 1.e-8;
1726: #endif
1727: #if defined(PETSC_USE_REAL_SINGLE)
1728:   snes->deltatol          = 1.e-6;
1729: #else
1730:   snes->deltatol          = 1.e-12;
1731: #endif
1732:   snes->divtol            = 1.e4;
1733:   snes->rnorm0            = 0;
1734:   snes->nfuncs            = 0;
1735:   snes->numFailures       = 0;
1736:   snes->maxFailures       = 1;
1737:   snes->linear_its        = 0;
1738:   snes->lagjacobian       = 1;
1739:   snes->jac_iter          = 0;
1740:   snes->lagjac_persist    = PETSC_FALSE;
1741:   snes->lagpreconditioner = 1;
1742:   snes->pre_iter          = 0;
1743:   snes->lagpre_persist    = PETSC_FALSE;
1744:   snes->numbermonitors    = 0;
1745:   snes->numberreasonviews = 0;
1746:   snes->data              = NULL;
1747:   snes->setupcalled       = PETSC_FALSE;
1748:   snes->ksp_ewconv        = PETSC_FALSE;
1749:   snes->nwork             = 0;
1750:   snes->work              = NULL;
1751:   snes->nvwork            = 0;
1752:   snes->vwork             = NULL;
1753:   snes->conv_hist_len     = 0;
1754:   snes->conv_hist_max     = 0;
1755:   snes->conv_hist         = NULL;
1756:   snes->conv_hist_its     = NULL;
1757:   snes->conv_hist_reset   = PETSC_TRUE;
1758:   snes->counters_reset    = PETSC_TRUE;
1759:   snes->vec_func_init_set = PETSC_FALSE;
1760:   snes->reason            = SNES_CONVERGED_ITERATING;
1761:   snes->npcside           = PC_RIGHT;
1762:   snes->setfromoptionscalled = 0;

1764:   snes->mf          = PETSC_FALSE;
1765:   snes->mf_operator = PETSC_FALSE;
1766:   snes->mf_version  = 1;

1768:   snes->numLinearSolveFailures = 0;
1769:   snes->maxLinearSolveFailures = 1;

1771:   snes->vizerotolerance = 1.e-8;
1772:   snes->checkjacdomainerror = PetscDefined(USE_DEBUG) ? PETSC_TRUE : PETSC_FALSE;

1774:   /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1775:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

1777:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1778:   PetscNewLog(snes,&kctx);

1780:   snes->kspconvctx  = (void*)kctx;
1781:   kctx->version     = 2;
1782:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1783:                              this was too large for some test cases */
1784:   kctx->rtol_last   = 0.0;
1785:   kctx->rtol_max    = .9;
1786:   kctx->gamma       = 1.0;
1787:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1788:   kctx->alpha2      = kctx->alpha;
1789:   kctx->threshold   = .1;
1790:   kctx->lresid_last = 0.0;
1791:   kctx->norm_last   = 0.0;

1793:   *outsnes = snes;
1794:   return(0);
1795: }

1797: /*MC
1798:     SNESFunction - Functional form used to convey the nonlinear function to be solved by SNES

1800:      Synopsis:
1801:      #include "petscsnes.h"
1802:      PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1804:      Collective on snes

1806:      Input Parameters:
1807: +     snes - the SNES context
1808: .     x    - state at which to evaluate residual
1809: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1811:      Output Parameter:
1812: .     f  - vector to put residual (function value)

1814:    Level: intermediate

1816: .seealso:   SNESSetFunction(), SNESGetFunction()
1817: M*/

1819: /*@C
1820:    SNESSetFunction - Sets the function evaluation routine and function
1821:    vector for use by the SNES routines in solving systems of nonlinear
1822:    equations.

1824:    Logically Collective on SNES

1826:    Input Parameters:
1827: +  snes - the SNES context
1828: .  r - vector to store function value
1829: .  f - function evaluation routine; see SNESFunction for calling sequence details
1830: -  ctx - [optional] user-defined context for private data for the
1831:          function evaluation routine (may be NULL)

1833:    Notes:
1834:    The Newton-like methods typically solve linear systems of the form
1835: $      f'(x) x = -f(x),
1836:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1838:    Level: beginner

1840: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1841: @*/
1842: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1843: {
1845:   DM             dm;

1849:   if (r) {
1852:     PetscObjectReference((PetscObject)r);
1853:     VecDestroy(&snes->vec_func);

1855:     snes->vec_func = r;
1856:   }
1857:   SNESGetDM(snes,&dm);
1858:   DMSNESSetFunction(dm,f,ctx);
1859:   return(0);
1860: }


1863: /*@C
1864:    SNESSetInitialFunction - Sets the function vector to be used as the
1865:    function norm at the initialization of the method.  In some
1866:    instances, the user has precomputed the function before calling
1867:    SNESSolve.  This function allows one to avoid a redundant call
1868:    to SNESComputeFunction in that case.

1870:    Logically Collective on SNES

1872:    Input Parameters:
1873: +  snes - the SNES context
1874: -  f - vector to store function value

1876:    Notes:
1877:    This should not be modified during the solution procedure.

1879:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1881:    Level: developer

1883: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1884: @*/
1885: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1886: {
1888:   Vec            vec_func;

1894:   if (snes->npcside== PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1895:     snes->vec_func_init_set = PETSC_FALSE;
1896:     return(0);
1897:   }
1898:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1899:   VecCopy(f, vec_func);

1901:   snes->vec_func_init_set = PETSC_TRUE;
1902:   return(0);
1903: }

1905: /*@
1906:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1907:    of the SNES method.

1909:    Logically Collective on SNES

1911:    Input Parameters:
1912: +  snes - the SNES context
1913: -  normschedule - the frequency of norm computation

1915:    Options Database Key:
1916: .  -snes_norm_schedule <none, always, initialonly, finalonly, initalfinalonly>

1918:    Notes:
1919:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1920:    of the nonlinear function and the taking of its norm at every iteration to
1921:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1922:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1923:    may either be monitored for convergence or not.  As these are often used as nonlinear
1924:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1925:    their solution.

1927:    Level: developer

1929: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1930: @*/
1931: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1932: {
1935:   snes->normschedule = normschedule;
1936:   return(0);
1937: }


1940: /*@
1941:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1942:    of the SNES method.

1944:    Logically Collective on SNES

1946:    Input Parameters:
1947: +  snes - the SNES context
1948: -  normschedule - the type of the norm used

1950:    Level: advanced

1952: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1953: @*/
1954: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1955: {
1958:   *normschedule = snes->normschedule;
1959:   return(0);
1960: }


1963: /*@
1964:   SNESSetFunctionNorm - Sets the last computed residual norm.

1966:   Logically Collective on SNES

1968:   Input Parameters:
1969: + snes - the SNES context

1971: - normschedule - the frequency of norm computation

1973:   Level: developer

1975: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1976: @*/
1977: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
1978: {
1981:   snes->norm = norm;
1982:   return(0);
1983: }

1985: /*@
1986:   SNESGetFunctionNorm - Gets the last computed norm of the residual

1988:   Not Collective

1990:   Input Parameter:
1991: . snes - the SNES context

1993:   Output Parameter:
1994: . norm - the last computed residual norm

1996:   Level: developer

1998: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1999: @*/
2000: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
2001: {
2005:   *norm = snes->norm;
2006:   return(0);
2007: }

2009: /*@
2010:   SNESGetUpdateNorm - Gets the last computed norm of the Newton update

2012:   Not Collective

2014:   Input Parameter:
2015: . snes - the SNES context

2017:   Output Parameter:
2018: . ynorm - the last computed update norm

2020:   Level: developer

2022: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), SNESGetFunctionNorm()
2023: @*/
2024: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
2025: {
2029:   *ynorm = snes->ynorm;
2030:   return(0);
2031: }

2033: /*@
2034:   SNESGetSolutionNorm - Gets the last computed norm of the solution

2036:   Not Collective

2038:   Input Parameter:
2039: . snes - the SNES context

2041:   Output Parameter:
2042: . xnorm - the last computed solution norm

2044:   Level: developer

2046: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), SNESGetFunctionNorm(), SNESGetUpdateNorm()
2047: @*/
2048: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2049: {
2053:   *xnorm = snes->xnorm;
2054:   return(0);
2055: }

2057: /*@C
2058:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
2059:    of the SNES method.

2061:    Logically Collective on SNES

2063:    Input Parameters:
2064: +  snes - the SNES context
2065: -  normschedule - the frequency of norm computation

2067:    Notes:
2068:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
2069:    of the nonlinear function and the taking of its norm at every iteration to
2070:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
2071:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
2072:    may either be monitored for convergence or not.  As these are often used as nonlinear
2073:    preconditioners, monitoring the norm of their error is not a useful enterprise within
2074:    their solution.

2076:    Level: developer

2078: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2079: @*/
2080: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
2081: {
2084:   snes->functype = type;
2085:   return(0);
2086: }


2089: /*@C
2090:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
2091:    of the SNES method.

2093:    Logically Collective on SNES

2095:    Input Parameters:
2096: +  snes - the SNES context
2097: -  normschedule - the type of the norm used

2099:    Level: advanced

2101: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2102: @*/
2103: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2104: {
2107:   *type = snes->functype;
2108:   return(0);
2109: }

2111: /*MC
2112:     SNESNGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

2114:      Synopsis:
2115: #include <petscsnes.h>
2116: $    SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);

2118:      Collective on snes

2120:      Input Parameters:
2121: +  X   - solution vector
2122: .  B   - RHS vector
2123: -  ctx - optional user-defined Gauss-Seidel context

2125:      Output Parameter:
2126: .  X   - solution vector

2128:    Level: intermediate

2130: .seealso:   SNESSetNGS(), SNESGetNGS()
2131: M*/

2133: /*@C
2134:    SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2135:    use with composed nonlinear solvers.

2137:    Input Parameters:
2138: +  snes   - the SNES context
2139: .  f - function evaluation routine to apply Gauss-Seidel see SNESNGSFunction
2140: -  ctx    - [optional] user-defined context for private data for the
2141:             smoother evaluation routine (may be NULL)

2143:    Notes:
2144:    The NGS routines are used by the composed nonlinear solver to generate
2145:     a problem appropriate update to the solution, particularly FAS.

2147:    Level: intermediate

2149: .seealso: SNESGetFunction(), SNESComputeNGS()
2150: @*/
2151: PetscErrorCode SNESSetNGS(SNES snes,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
2152: {
2154:   DM             dm;

2158:   SNESGetDM(snes,&dm);
2159:   DMSNESSetNGS(dm,f,ctx);
2160:   return(0);
2161: }

2163: PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
2164: {
2166:   DM             dm;
2167:   DMSNES         sdm;

2170:   SNESGetDM(snes,&dm);
2171:   DMGetDMSNES(dm,&sdm);
2172:   if (!sdm->ops->computepfunction) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");
2173:   if (!sdm->ops->computepjacobian) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard Jacobian.");
2174:   /*  A(x)*x - b(x) */
2175:   PetscStackPush("SNES Picard user function");
2176:   (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
2177:   PetscStackPop;
2178:   PetscStackPush("SNES Picard user Jacobian");
2179:   (*sdm->ops->computepjacobian)(snes,x,snes->jacobian,snes->jacobian_pre,sdm->pctx);
2180:   PetscStackPop;
2181:   VecScale(f,-1.0);
2182:   MatMultAdd(snes->jacobian,x,f,f);
2183:   return(0);
2184: }

2186: PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat J,Mat B,void *ctx)
2187: {
2189:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2190:   return(0);
2191: }

2193: /*@C
2194:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

2196:    Logically Collective on SNES

2198:    Input Parameters:
2199: +  snes - the SNES context
2200: .  r - vector to store function value
2201: .  b - function evaluation routine
2202: .  Amat - matrix with which A(x) x - b(x) is to be computed
2203: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
2204: .  J  - function to compute matrix value, see SNESJacobianFunction for details on its calling sequence
2205: -  ctx - [optional] user-defined context for private data for the
2206:          function evaluation routine (may be NULL)

2208:    Notes:
2209:     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
2210:     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.

2212:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

2214: $     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}
2215: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

2217:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

2219:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2220:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

2222:    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
2223:    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
2224:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

2226:    Level: intermediate

2228: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard(), SNESJacobianFunction
2229: @*/
2230: 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)
2231: {
2233:   DM             dm;

2237:   SNESGetDM(snes, &dm);
2238:   DMSNESSetPicard(dm,b,J,ctx);
2239:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
2240:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
2241:   return(0);
2242: }

2244: /*@C
2245:    SNESGetPicard - Returns the context for the Picard iteration

2247:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

2249:    Input Parameter:
2250: .  snes - the SNES context

2252:    Output Parameter:
2253: +  r - the function (or NULL)
2254: .  f - the function (or NULL); see SNESFunction for calling sequence details
2255: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
2256: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
2257: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
2258: -  ctx - the function context (or NULL)

2260:    Level: advanced

2262: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
2263: @*/
2264: 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)
2265: {
2267:   DM             dm;

2271:   SNESGetFunction(snes,r,NULL,NULL);
2272:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
2273:   SNESGetDM(snes,&dm);
2274:   DMSNESGetPicard(dm,f,J,ctx);
2275:   return(0);
2276: }

2278: /*@C
2279:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

2281:    Logically Collective on SNES

2283:    Input Parameters:
2284: +  snes - the SNES context
2285: .  func - function evaluation routine
2286: -  ctx - [optional] user-defined context for private data for the
2287:          function evaluation routine (may be NULL)

2289:    Calling sequence of func:
2290: $    func (SNES snes,Vec x,void *ctx);

2292: .  f - function vector
2293: -  ctx - optional user-defined function context

2295:    Level: intermediate

2297: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
2298: @*/
2299: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
2300: {
2303:   if (func) snes->ops->computeinitialguess = func;
2304:   if (ctx)  snes->initialguessP            = ctx;
2305:   return(0);
2306: }

2308: /* --------------------------------------------------------------- */
2309: /*@C
2310:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
2311:    it assumes a zero right hand side.

2313:    Logically Collective on SNES

2315:    Input Parameter:
2316: .  snes - the SNES context

2318:    Output Parameter:
2319: .  rhs - the right hand side vector or NULL if the right hand side vector is null

2321:    Level: intermediate

2323: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2324: @*/
2325: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2326: {
2330:   *rhs = snes->vec_rhs;
2331:   return(0);
2332: }

2334: /*@
2335:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2337:    Collective on SNES

2339:    Input Parameters:
2340: +  snes - the SNES context
2341: -  x - input vector

2343:    Output Parameter:
2344: .  y - function vector, as set by SNESSetFunction()

2346:    Notes:
2347:    SNESComputeFunction() is typically used within nonlinear solvers
2348:    implementations, so most users would not generally call this routine
2349:    themselves.

2351:    Level: developer

2353: .seealso: SNESSetFunction(), SNESGetFunction()
2354: @*/
2355: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2356: {
2358:   DM             dm;
2359:   DMSNES         sdm;

2367:   VecValidValues(x,2,PETSC_TRUE);

2369:   SNESGetDM(snes,&dm);
2370:   DMGetDMSNES(dm,&sdm);
2371:   if (sdm->ops->computefunction) {
2372:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2373:       PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2374:     }
2375:     VecLockReadPush(x);
2376:     PetscStackPush("SNES user function");
2377:     /* ensure domainerror is false prior to computefunction evaluation (may not have been reset) */
2378:     snes->domainerror = PETSC_FALSE;
2379:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2380:     PetscStackPop;
2381:     VecLockReadPop(x);
2382:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2383:       PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2384:     }
2385:   } else if (snes->vec_rhs) {
2386:     MatMult(snes->jacobian, x, y);
2387:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2388:   if (snes->vec_rhs) {
2389:     VecAXPY(y,-1.0,snes->vec_rhs);
2390:   }
2391:   snes->nfuncs++;
2392:   /*
2393:      domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2394:      propagate the value to all processes
2395:   */
2396:   if (snes->domainerror) {
2397:     VecSetInf(y);
2398:   }
2399:   return(0);
2400: }

2402: /*@
2403:    SNESComputeNGS - Calls the Gauss-Seidel function that has been set with  SNESSetNGS().

2405:    Collective on SNES

2407:    Input Parameters:
2408: +  snes - the SNES context
2409: .  x - input vector
2410: -  b - rhs vector

2412:    Output Parameter:
2413: .  x - new solution vector

2415:    Notes:
2416:    SNESComputeNGS() is typically used within composed nonlinear solver
2417:    implementations, so most users would not generally call this routine
2418:    themselves.

2420:    Level: developer

2422: .seealso: SNESSetNGS(), SNESComputeFunction()
2423: @*/
2424: PetscErrorCode  SNESComputeNGS(SNES snes,Vec b,Vec x)
2425: {
2427:   DM             dm;
2428:   DMSNES         sdm;

2436:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2437:   PetscLogEventBegin(SNES_NGSEval,snes,x,b,0);
2438:   SNESGetDM(snes,&dm);
2439:   DMGetDMSNES(dm,&sdm);
2440:   if (sdm->ops->computegs) {
2441:     if (b) {VecLockReadPush(b);}
2442:     PetscStackPush("SNES user NGS");
2443:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2444:     PetscStackPop;
2445:     if (b) {VecLockReadPop(b);}
2446:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2447:   PetscLogEventEnd(SNES_NGSEval,snes,x,b,0);
2448:   return(0);
2449: }

2451: PetscErrorCode SNESTestJacobian(SNES snes)
2452: {
2453:   Mat               A,B,C,D,jacobian;
2454:   Vec               x = snes->vec_sol,f = snes->vec_func;
2455:   PetscErrorCode    ierr;
2456:   PetscReal         nrm,gnorm;
2457:   PetscReal         threshold = 1.e-5;
2458:   MatType           mattype;
2459:   PetscInt          m,n,M,N;
2460:   void              *functx;
2461:   PetscBool         complete_print = PETSC_FALSE,threshold_print = PETSC_FALSE,test = PETSC_FALSE,flg,istranspose;
2462:   PetscViewer       viewer,mviewer;
2463:   MPI_Comm          comm;
2464:   PetscInt          tabs;
2465:   static PetscBool  directionsprinted = PETSC_FALSE;
2466:   PetscViewerFormat format;

2469:   PetscObjectOptionsBegin((PetscObject)snes);
2470:   PetscOptionsName("-snes_test_jacobian","Compare hand-coded and finite difference Jacobians","None",&test);
2471:   PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold,NULL);
2472:   PetscOptionsViewer("-snes_test_jacobian_view","View difference between hand-coded and finite difference Jacobians element entries","None",&mviewer,&format,&complete_print);
2473:   if (!complete_print) {
2474:     PetscOptionsDeprecated("-snes_test_jacobian_display","-snes_test_jacobian_view","3.13",NULL);
2475:     PetscOptionsViewer("-snes_test_jacobian_display","Display difference between hand-coded and finite difference Jacobians","None",&mviewer,&format,&complete_print);
2476:   }
2477:   /* for compatibility with PETSc 3.9 and older. */
2478:   PetscOptionsDeprecated("-snes_test_jacobian_display_threshold","-snes_test_jacobian","3.13","-snes_test_jacobian accepts an optional threshold (since v3.10)");
2479:   PetscOptionsReal("-snes_test_jacobian_display_threshold", "Display difference between hand-coded and finite difference Jacobians which exceed input threshold", "None", threshold, &threshold, &threshold_print);
2480:   PetscOptionsEnd();
2481:   if (!test) return(0);

2483:   PetscObjectGetComm((PetscObject)snes,&comm);
2484:   PetscViewerASCIIGetStdout(comm,&viewer);
2485:   PetscViewerASCIIGetTab(viewer, &tabs);
2486:   PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel);
2487:   PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian -------------\n");
2488:   if (!complete_print && !directionsprinted) {
2489:     PetscViewerASCIIPrintf(viewer,"  Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n");
2490:     PetscViewerASCIIPrintf(viewer,"    of hand-coded and finite difference Jacobian entries greater than <threshold>.\n");
2491:   }
2492:   if (!directionsprinted) {
2493:     PetscViewerASCIIPrintf(viewer,"  Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n");
2494:     PetscViewerASCIIPrintf(viewer,"    O(1.e-8), the hand-coded Jacobian is probably correct.\n");
2495:     directionsprinted = PETSC_TRUE;
2496:   }
2497:   if (complete_print) {
2498:     PetscViewerPushFormat(mviewer,format);
2499:   }

2501:   PetscObjectTypeCompare((PetscObject)snes->jacobian,MATMFFD,&flg);
2502:   if (!flg) jacobian = snes->jacobian;
2503:   else jacobian = snes->jacobian_pre;

2505:   if (!x) {
2506:     MatCreateVecs(jacobian, &x, NULL);
2507:   } else {
2508:     PetscObjectReference((PetscObject) x);
2509:   }
2510:   if (!f) {
2511:     VecDuplicate(x, &f);
2512:   } else {
2513:     PetscObjectReference((PetscObject) f);
2514:   }
2515:   /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2516:   SNESComputeFunction(snes,x,f);
2517:   VecDestroy(&f);
2518:   PetscObjectTypeCompare((PetscObject)snes,SNESKSPTRANSPOSEONLY,&istranspose);
2519:   while (jacobian) {
2520:     Mat JT = NULL, Jsave = NULL;

2522:     if (istranspose) {
2523:       MatCreateTranspose(jacobian,&JT);
2524:       Jsave = jacobian;
2525:       jacobian = JT;
2526:     }
2527:     PetscObjectBaseTypeCompareAny((PetscObject)jacobian,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPISBAIJ,"");
2528:     if (flg) {
2529:       A    = jacobian;
2530:       PetscObjectReference((PetscObject)A);
2531:     } else {
2532:       MatComputeOperator(jacobian,MATAIJ,&A);
2533:     }

2535:     MatGetType(A,&mattype);
2536:     MatGetSize(A,&M,&N);
2537:     MatGetLocalSize(A,&m,&n);
2538:     MatCreate(PetscObjectComm((PetscObject)A),&B);
2539:     MatSetType(B,mattype);
2540:     MatSetSizes(B,m,n,M,N);
2541:     MatSetBlockSizesFromMats(B,A,A);
2542:     MatSetUp(B);
2543:     MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2545:     SNESGetFunction(snes,NULL,NULL,&functx);
2546:     SNESComputeJacobianDefault(snes,x,B,B,functx);

2548:     MatDuplicate(B,MAT_COPY_VALUES,&D);
2549:     MatAYPX(D,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2550:     MatNorm(D,NORM_FROBENIUS,&nrm);
2551:     MatNorm(A,NORM_FROBENIUS,&gnorm);
2552:     MatDestroy(&D);
2553:     if (!gnorm) gnorm = 1; /* just in case */
2554:     PetscViewerASCIIPrintf(viewer,"  ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n",(double)(nrm/gnorm),(double)nrm);

2556:     if (complete_print) {
2557:       PetscViewerASCIIPrintf(viewer,"  Hand-coded Jacobian ----------\n");
2558:       MatView(A,mviewer);
2559:       PetscViewerASCIIPrintf(viewer,"  Finite difference Jacobian ----------\n");
2560:       MatView(B,mviewer);
2561:     }

2563:     if (threshold_print || complete_print) {
2564:       PetscInt          Istart, Iend, *ccols, bncols, cncols, j, row;
2565:       PetscScalar       *cvals;
2566:       const PetscInt    *bcols;
2567:       const PetscScalar *bvals;

2569:       MatCreate(PetscObjectComm((PetscObject)A),&C);
2570:       MatSetType(C,mattype);
2571:       MatSetSizes(C,m,n,M,N);
2572:       MatSetBlockSizesFromMats(C,A,A);
2573:       MatSetUp(C);
2574:       MatSetOption(C,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2576:       MatAYPX(B,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2577:       MatGetOwnershipRange(B,&Istart,&Iend);

2579:       for (row = Istart; row < Iend; row++) {
2580:         MatGetRow(B,row,&bncols,&bcols,&bvals);
2581:         PetscMalloc2(bncols,&ccols,bncols,&cvals);
2582:         for (j = 0, cncols = 0; j < bncols; j++) {
2583:           if (PetscAbsScalar(bvals[j]) > threshold) {
2584:             ccols[cncols] = bcols[j];
2585:             cvals[cncols] = bvals[j];
2586:             cncols += 1;
2587:           }
2588:         }
2589:         if (cncols) {
2590:           MatSetValues(C,1,&row,cncols,ccols,cvals,INSERT_VALUES);
2591:         }
2592:         MatRestoreRow(B,row,&bncols,&bcols,&bvals);
2593:         PetscFree2(ccols,cvals);
2594:       }
2595:       MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
2596:       MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
2597:       PetscViewerASCIIPrintf(viewer,"  Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n",(double)threshold);
2598:       MatView(C,complete_print ? mviewer : viewer);
2599:       MatDestroy(&C);
2600:     }
2601:     MatDestroy(&A);
2602:     MatDestroy(&B);
2603:     MatDestroy(&JT);
2604:     if (Jsave) jacobian = Jsave;
2605:     if (jacobian != snes->jacobian_pre) {
2606:       jacobian = snes->jacobian_pre;
2607:       PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian for preconditioner -------------\n");
2608:     }
2609:     else jacobian = NULL;
2610:   }
2611:   VecDestroy(&x);
2612:   if (complete_print) {
2613:     PetscViewerPopFormat(mviewer);
2614:   }
2615:   if (mviewer) { PetscViewerDestroy(&mviewer); }
2616:   PetscViewerASCIISetTab(viewer,tabs);
2617:   return(0);
2618: }

2620: /*@
2621:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2623:    Collective on SNES

2625:    Input Parameters:
2626: +  snes - the SNES context
2627: -  x - input vector

2629:    Output Parameters:
2630: +  A - Jacobian matrix
2631: -  B - optional preconditioning matrix

2633:   Options Database Keys:
2634: +    -snes_lag_preconditioner <lag>
2635: .    -snes_lag_jacobian <lag>
2636: .    -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.
2637: .    -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
2638: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2639: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2640: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2641: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2642: .    -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2643: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2644: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2645: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2646: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2647: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2648: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2651:    Notes:
2652:    Most users should not need to explicitly call this routine, as it
2653:    is used internally within the nonlinear solvers.

2655:    Developer Notes:
2656:     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
2657:       for with the SNESType of test that has been removed.

2659:    Level: developer

2661: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2662: @*/
2663: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat A,Mat B)
2664: {
2666:   PetscBool      flag;
2667:   DM             dm;
2668:   DMSNES         sdm;
2669:   KSP            ksp;

2675:   VecValidValues(X,2,PETSC_TRUE);
2676:   SNESGetDM(snes,&dm);
2677:   DMGetDMSNES(dm,&sdm);

2679:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2681:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2683:   if (snes->lagjacobian == -2) {
2684:     snes->lagjacobian = -1;

2686:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2687:   } else if (snes->lagjacobian == -1) {
2688:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2689:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2690:     if (flag) {
2691:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2692:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2693:     }
2694:     return(0);
2695:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2696:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2697:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2698:     if (flag) {
2699:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2700:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2701:     }
2702:     return(0);
2703:   }
2704:   if (snes->npc && snes->npcside== PC_LEFT) {
2705:     MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2706:     MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2707:     return(0);
2708:   }

2710:   PetscLogEventBegin(SNES_JacobianEval,snes,X,A,B);
2711:   VecLockReadPush(X);
2712:   PetscStackPush("SNES user Jacobian function");
2713:   (*sdm->ops->computejacobian)(snes,X,A,B,sdm->jacobianctx);
2714:   PetscStackPop;
2715:   VecLockReadPop(X);
2716:   PetscLogEventEnd(SNES_JacobianEval,snes,X,A,B);

2718:   /* attach latest linearization point to the preconditioning matrix */
2719:   PetscObjectCompose((PetscObject)B,"__SNES_latest_X",(PetscObject)X);

2721:   /* the next line ensures that snes->ksp exists */
2722:   SNESGetKSP(snes,&ksp);
2723:   if (snes->lagpreconditioner == -2) {
2724:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");
2725:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2726:     snes->lagpreconditioner = -1;
2727:   } else if (snes->lagpreconditioner == -1) {
2728:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2729:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2730:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2731:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2732:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2733:   } else {
2734:     PetscInfo(snes,"Rebuilding preconditioner\n");
2735:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2736:   }

2738:   SNESTestJacobian(snes);
2739:   /* make sure user returned a correct Jacobian and preconditioner */
2742:   {
2743:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2744:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit",NULL,NULL,&flag);
2745:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",NULL,NULL,&flag_draw);
2746:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",NULL,NULL,&flag_contour);
2747:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_operator",NULL,NULL,&flag_operator);
2748:     if (flag || flag_draw || flag_contour) {
2749:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2750:       PetscViewer  vdraw,vstdout;
2751:       PetscBool    flg;
2752:       if (flag_operator) {
2753:         MatComputeOperator(A,MATAIJ,&Bexp_mine);
2754:         Bexp = Bexp_mine;
2755:       } else {
2756:         /* See if the preconditioning matrix can be viewed and added directly */
2757:         PetscObjectBaseTypeCompareAny((PetscObject)B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2758:         if (flg) Bexp = B;
2759:         else {
2760:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2761:           MatComputeOperator(B,MATAIJ,&Bexp_mine);
2762:           Bexp = Bexp_mine;
2763:         }
2764:       }
2765:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2766:       SNESComputeJacobianDefault(snes,X,FDexp,FDexp,NULL);
2767:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2768:       if (flag_draw || flag_contour) {
2769:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2770:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2771:       } else vdraw = NULL;
2772:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2773:       if (flag) {MatView(Bexp,vstdout);}
2774:       if (vdraw) {MatView(Bexp,vdraw);}
2775:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2776:       if (flag) {MatView(FDexp,vstdout);}
2777:       if (vdraw) {MatView(FDexp,vdraw);}
2778:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2779:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2780:       if (flag) {MatView(FDexp,vstdout);}
2781:       if (vdraw) {              /* Always use contour for the difference */
2782:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2783:         MatView(FDexp,vdraw);
2784:         PetscViewerPopFormat(vdraw);
2785:       }
2786:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2787:       PetscViewerDestroy(&vdraw);
2788:       MatDestroy(&Bexp_mine);
2789:       MatDestroy(&FDexp);
2790:     }
2791:   }
2792:   {
2793:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2794:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2795:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring",NULL,NULL,&flag);
2796:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_display",NULL,NULL,&flag_display);
2797:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",NULL,NULL,&flag_draw);
2798:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",NULL,NULL,&flag_contour);
2799:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",NULL,NULL,&flag_threshold);
2800:     if (flag_threshold) {
2801:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2802:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2803:     }
2804:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2805:       Mat            Bfd;
2806:       PetscViewer    vdraw,vstdout;
2807:       MatColoring    coloring;
2808:       ISColoring     iscoloring;
2809:       MatFDColoring  matfdcoloring;
2810:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2811:       void           *funcctx;
2812:       PetscReal      norm1,norm2,normmax;

2814:       MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2815:       MatColoringCreate(Bfd,&coloring);
2816:       MatColoringSetType(coloring,MATCOLORINGSL);
2817:       MatColoringSetFromOptions(coloring);
2818:       MatColoringApply(coloring,&iscoloring);
2819:       MatColoringDestroy(&coloring);
2820:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2821:       MatFDColoringSetFromOptions(matfdcoloring);
2822:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2823:       ISColoringDestroy(&iscoloring);

2825:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2826:       SNESGetFunction(snes,NULL,&func,&funcctx);
2827:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2828:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2829:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2830:       MatFDColoringSetFromOptions(matfdcoloring);
2831:       MatFDColoringApply(Bfd,matfdcoloring,X,snes);
2832:       MatFDColoringDestroy(&matfdcoloring);

2834:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2835:       if (flag_draw || flag_contour) {
2836:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2837:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2838:       } else vdraw = NULL;
2839:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2840:       if (flag_display) {MatView(B,vstdout);}
2841:       if (vdraw) {MatView(B,vdraw);}
2842:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2843:       if (flag_display) {MatView(Bfd,vstdout);}
2844:       if (vdraw) {MatView(Bfd,vdraw);}
2845:       MatAYPX(Bfd,-1.0,B,SAME_NONZERO_PATTERN);
2846:       MatNorm(Bfd,NORM_1,&norm1);
2847:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2848:       MatNorm(Bfd,NORM_MAX,&normmax);
2849:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2850:       if (flag_display) {MatView(Bfd,vstdout);}
2851:       if (vdraw) {              /* Always use contour for the difference */
2852:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2853:         MatView(Bfd,vdraw);
2854:         PetscViewerPopFormat(vdraw);
2855:       }
2856:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2858:       if (flag_threshold) {
2859:         PetscInt bs,rstart,rend,i;
2860:         MatGetBlockSize(B,&bs);
2861:         MatGetOwnershipRange(B,&rstart,&rend);
2862:         for (i=rstart; i<rend; i++) {
2863:           const PetscScalar *ba,*ca;
2864:           const PetscInt    *bj,*cj;
2865:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2866:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2867:           MatGetRow(B,i,&bn,&bj,&ba);
2868:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2869:           if (bn != cn) SETERRQ(((PetscObject)A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2870:           for (j=0; j<bn; j++) {
2871:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2872:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2873:               maxentrycol = bj[j];
2874:               maxentry    = PetscRealPart(ba[j]);
2875:             }
2876:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2877:               maxdiffcol = bj[j];
2878:               maxdiff    = PetscRealPart(ca[j]);
2879:             }
2880:             if (rdiff > maxrdiff) {
2881:               maxrdiffcol = bj[j];
2882:               maxrdiff    = rdiff;
2883:             }
2884:           }
2885:           if (maxrdiff > 1) {
2886:             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);
2887:             for (j=0; j<bn; j++) {
2888:               PetscReal rdiff;
2889:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2890:               if (rdiff > 1) {
2891:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2892:               }
2893:             }
2894:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2895:           }
2896:           MatRestoreRow(B,i,&bn,&bj,&ba);
2897:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2898:         }
2899:       }
2900:       PetscViewerDestroy(&vdraw);
2901:       MatDestroy(&Bfd);
2902:     }
2903:   }
2904:   return(0);
2905: }

2907: /*MC
2908:     SNESJacobianFunction - Function used to convey the nonlinear Jacobian of the function to be solved by SNES

2910:      Synopsis:
2911:      #include "petscsnes.h"
2912:      PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);

2914:      Collective on snes

2916:     Input Parameters:
2917: +  x - input vector, the Jacobian is to be computed at this value
2918: -  ctx - [optional] user-defined Jacobian context

2920:     Output Parameters:
2921: +  Amat - the matrix that defines the (approximate) Jacobian
2922: -  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.

2924:    Level: intermediate

2926: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2927: M*/

2929: /*@C
2930:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2931:    location to store the matrix.

2933:    Logically Collective on SNES

2935:    Input Parameters:
2936: +  snes - the SNES context
2937: .  Amat - the matrix that defines the (approximate) Jacobian
2938: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2939: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value), see SNESJacobianFunction for details
2940: -  ctx - [optional] user-defined context for private data for the
2941:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2943:    Notes:
2944:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2945:    each matrix.

2947:    If you know the operator Amat has a null space you can use MatSetNullSpace() and MatSetTransposeNullSpace() to supply the null
2948:    space to Amat and the KSP solvers will automatically use that null space as needed during the solution process.

2950:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2951:    must be a MatFDColoring.

2953:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2954:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2956:    Level: beginner

2958: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J,
2959:           SNESSetPicard(), SNESJacobianFunction
2960: @*/
2961: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2962: {
2964:   DM             dm;

2972:   SNESGetDM(snes,&dm);
2973:   DMSNESSetJacobian(dm,J,ctx);
2974:   if (Amat) {
2975:     PetscObjectReference((PetscObject)Amat);
2976:     MatDestroy(&snes->jacobian);

2978:     snes->jacobian = Amat;
2979:   }
2980:   if (Pmat) {
2981:     PetscObjectReference((PetscObject)Pmat);
2982:     MatDestroy(&snes->jacobian_pre);

2984:     snes->jacobian_pre = Pmat;
2985:   }
2986:   return(0);
2987: }

2989: /*@C
2990:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2991:    provided context for evaluating the Jacobian.

2993:    Not Collective, but Mat object will be parallel if SNES object is

2995:    Input Parameter:
2996: .  snes - the nonlinear solver context

2998:    Output Parameters:
2999: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
3000: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
3001: .  J - location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
3002: -  ctx - location to stash Jacobian ctx (or NULL)

3004:    Level: advanced

3006: .seealso: SNESSetJacobian(), SNESComputeJacobian(), SNESJacobianFunction, SNESGetFunction()
3007: @*/
3008: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
3009: {
3011:   DM             dm;
3012:   DMSNES         sdm;

3016:   if (Amat) *Amat = snes->jacobian;
3017:   if (Pmat) *Pmat = snes->jacobian_pre;
3018:   SNESGetDM(snes,&dm);
3019:   DMGetDMSNES(dm,&sdm);
3020:   if (J) *J = sdm->ops->computejacobian;
3021:   if (ctx) *ctx = sdm->jacobianctx;
3022:   return(0);
3023: }

3025: static PetscErrorCode SNESSetDefaultComputeJacobian(SNES snes)
3026: {
3028:   DM             dm;
3029:   DMSNES         sdm;

3032:   SNESGetDM(snes,&dm);
3033:   DMGetDMSNES(dm,&sdm);
3034:   if (!sdm->ops->computejacobian && snes->jacobian_pre) {
3035:     DM        dm;
3036:     PetscBool isdense,ismf;

3038:     SNESGetDM(snes,&dm);
3039:     PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre,&isdense,MATSEQDENSE,MATMPIDENSE,MATDENSE,NULL);
3040:     PetscObjectTypeCompareAny((PetscObject)snes->jacobian_pre,&ismf,MATMFFD,MATSHELL,NULL);
3041:     if (isdense) {
3042:       DMSNESSetJacobian(dm,SNESComputeJacobianDefault,NULL);
3043:     } else if (!ismf) {
3044:       DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
3045:     }
3046:   }
3047:   return(0);
3048: }

3050: /*@
3051:    SNESSetUp - Sets up the internal data structures for the later use
3052:    of a nonlinear solver.

3054:    Collective on SNES

3056:    Input Parameters:
3057: .  snes - the SNES context

3059:    Notes:
3060:    For basic use of the SNES solvers the user need not explicitly call
3061:    SNESSetUp(), since these actions will automatically occur during
3062:    the call to SNESSolve().  However, if one wishes to control this
3063:    phase separately, SNESSetUp() should be called after SNESCreate()
3064:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

3066:    Level: advanced

3068: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
3069: @*/
3070: PetscErrorCode  SNESSetUp(SNES snes)
3071: {
3073:   DM             dm;
3074:   DMSNES         sdm;
3075:   SNESLineSearch linesearch, pclinesearch;
3076:   void           *lsprectx,*lspostctx;
3077:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
3078:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
3079:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
3080:   Vec            f,fpc;
3081:   void           *funcctx;
3082:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
3083:   void           *jacctx,*appctx;
3084:   Mat            j,jpre;

3088:   if (snes->setupcalled) return(0);
3089:   PetscLogEventBegin(SNES_Setup,snes,0,0,0);

3091:   if (!((PetscObject)snes)->type_name) {
3092:     SNESSetType(snes,SNESNEWTONLS);
3093:   }

3095:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

3097:   SNESGetDM(snes,&dm);
3098:   DMGetDMSNES(dm,&sdm);
3099:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
3100:   SNESSetDefaultComputeJacobian(snes);

3102:   if (!snes->vec_func) {
3103:     DMCreateGlobalVector(dm,&snes->vec_func);
3104:   }

3106:   if (!snes->ksp) {
3107:     SNESGetKSP(snes, &snes->ksp);
3108:   }

3110:   if (snes->linesearch) {
3111:     SNESGetLineSearch(snes, &snes->linesearch);
3112:     SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);
3113:   }

3115:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3116:     snes->mf          = PETSC_TRUE;
3117:     snes->mf_operator = PETSC_FALSE;
3118:   }

3120:   if (snes->npc) {
3121:     /* copy the DM over */
3122:     SNESGetDM(snes,&dm);
3123:     SNESSetDM(snes->npc,dm);

3125:     SNESGetFunction(snes,&f,&func,&funcctx);
3126:     VecDuplicate(f,&fpc);
3127:     SNESSetFunction(snes->npc,fpc,func,funcctx);
3128:     SNESGetJacobian(snes,&j,&jpre,&jac,&jacctx);
3129:     SNESSetJacobian(snes->npc,j,jpre,jac,jacctx);
3130:     SNESGetApplicationContext(snes,&appctx);
3131:     SNESSetApplicationContext(snes->npc,appctx);
3132:     VecDestroy(&fpc);

3134:     /* copy the function pointers over */
3135:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->npc);

3137:     /* default to 1 iteration */
3138:     SNESSetTolerances(snes->npc,0.0,0.0,0.0,1,snes->npc->max_funcs);
3139:     if (snes->npcside==PC_RIGHT) {
3140:       SNESSetNormSchedule(snes->npc,SNES_NORM_FINAL_ONLY);
3141:     } else {
3142:       SNESSetNormSchedule(snes->npc,SNES_NORM_NONE);
3143:     }
3144:     SNESSetFromOptions(snes->npc);

3146:     /* copy the line search context over */
3147:     if (snes->linesearch && snes->npc->linesearch) {
3148:       SNESGetLineSearch(snes,&linesearch);
3149:       SNESGetLineSearch(snes->npc,&pclinesearch);
3150:       SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
3151:       SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
3152:       SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
3153:       SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
3154:       PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
3155:     }
3156:   }
3157:   if (snes->mf) {
3158:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
3159:   }
3160:   if (snes->ops->usercompute && !snes->user) {
3161:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
3162:   }

3164:   snes->jac_iter = 0;
3165:   snes->pre_iter = 0;

3167:   if (snes->ops->setup) {
3168:     (*snes->ops->setup)(snes);
3169:   }

3171:   SNESSetDefaultComputeJacobian(snes);

3173:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3174:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3175:       if (snes->linesearch){
3176:         SNESGetLineSearch(snes,&linesearch);
3177:         SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultNPC);
3178:       }
3179:     }
3180:   }
3181:   PetscLogEventEnd(SNES_Setup,snes,0,0,0);
3182:   snes->setupcalled = PETSC_TRUE;
3183:   return(0);
3184: }

3186: /*@
3187:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

3189:    Collective on SNES

3191:    Input Parameter:
3192: .  snes - iterative context obtained from SNESCreate()

3194:    Level: intermediate

3196:    Notes:
3197:     Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

3199: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
3200: @*/
3201: PetscErrorCode  SNESReset(SNES snes)
3202: {

3207:   if (snes->ops->userdestroy && snes->user) {
3208:     (*snes->ops->userdestroy)((void**)&snes->user);
3209:     snes->user = NULL;
3210:   }
3211:   if (snes->npc) {
3212:     SNESReset(snes->npc);
3213:   }

3215:   if (snes->ops->reset) {
3216:     (*snes->ops->reset)(snes);
3217:   }
3218:   if (snes->ksp) {
3219:     KSPReset(snes->ksp);
3220:   }

3222:   if (snes->linesearch) {
3223:     SNESLineSearchReset(snes->linesearch);
3224:   }

3226:   VecDestroy(&snes->vec_rhs);
3227:   VecDestroy(&snes->vec_sol);
3228:   VecDestroy(&snes->vec_sol_update);
3229:   VecDestroy(&snes->vec_func);
3230:   MatDestroy(&snes->jacobian);
3231:   MatDestroy(&snes->jacobian_pre);
3232:   VecDestroyVecs(snes->nwork,&snes->work);
3233:   VecDestroyVecs(snes->nvwork,&snes->vwork);

3235:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

3237:   snes->nwork       = snes->nvwork = 0;
3238:   snes->setupcalled = PETSC_FALSE;
3239:   return(0);
3240: }

3242: /*@
3243:    SNESConvergedReasonViewCancel - Clears all the reasonview functions for a SNES object.

3245:    Collective on SNES

3247:    Input Parameter:
3248: .  snes - iterative context obtained from SNESCreate()

3250:    Level: intermediate

3252: .seealso: SNESCreate(), SNESDestroy(), SNESReset()
3253: @*/
3254: PetscErrorCode  SNESConvergedReasonViewCancel(SNES snes)
3255: {
3257:   PetscInt       i;

3261:   for (i=0; i<snes->numberreasonviews; i++) {
3262:     if (snes->reasonviewdestroy[i]) {
3263:       (*snes->reasonviewdestroy[i])(&snes->reasonviewcontext[i]);
3264:     }
3265:   }
3266:   snes->numberreasonviews = 0;
3267:   return(0);
3268: }

3270: /*@C
3271:    SNESDestroy - Destroys the nonlinear solver context that was created
3272:    with SNESCreate().

3274:    Collective on SNES

3276:    Input Parameter:
3277: .  snes - the SNES context

3279:    Level: beginner

3281: .seealso: SNESCreate(), SNESSolve()
3282: @*/
3283: PetscErrorCode  SNESDestroy(SNES *snes)
3284: {

3288:   if (!*snes) return(0);
3290:   if (--((PetscObject)(*snes))->refct > 0) {*snes = NULL; return(0);}

3292:   SNESReset((*snes));
3293:   SNESDestroy(&(*snes)->npc);

3295:   /* if memory was published with SAWs then destroy it */
3296:   PetscObjectSAWsViewOff((PetscObject)*snes);
3297:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

3299:   if ((*snes)->dm) {DMCoarsenHookRemove((*snes)->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,*snes);}
3300:   DMDestroy(&(*snes)->dm);
3301:   KSPDestroy(&(*snes)->ksp);
3302:   SNESLineSearchDestroy(&(*snes)->linesearch);

3304:   PetscFree((*snes)->kspconvctx);
3305:   if ((*snes)->ops->convergeddestroy) {
3306:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
3307:   }
3308:   if ((*snes)->conv_hist_alloc) {
3309:     PetscFree2((*snes)->conv_hist,(*snes)->conv_hist_its);
3310:   }
3311:   SNESMonitorCancel((*snes));
3312:   SNESConvergedReasonViewCancel((*snes));
3313:   PetscHeaderDestroy(snes);
3314:   return(0);
3315: }

3317: /* ----------- Routines to set solver parameters ---------- */

3319: /*@
3320:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

3322:    Logically Collective on SNES

3324:    Input Parameters:
3325: +  snes - the SNES context
3326: -  lag - 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3327:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3329:    Options Database Keys:
3330: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3331: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3332: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3333: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag

3335:    Notes:
3336:    The default is 1
3337:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or SNESSetLagPreconditionerPersists() was called

3339:    SNESSetLagPreconditionerPersists() allows using the same uniform lagging (for example every second solve) across multiple solves.

3341:    Level: intermediate

3343: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetLagPreconditionerPersists(),
3344:           SNESSetLagJacobianPersists()

3346: @*/
3347: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
3348: {
3351:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3352:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3354:   snes->lagpreconditioner = lag;
3355:   return(0);
3356: }

3358: /*@
3359:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

3361:    Logically Collective on SNES

3363:    Input Parameters:
3364: +  snes - the SNES context
3365: -  steps - the number of refinements to do, defaults to 0

3367:    Options Database Keys:
3368: .    -snes_grid_sequence <steps>

3370:    Level: intermediate

3372:    Notes:
3373:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3375: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetGridSequence()

3377: @*/
3378: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
3379: {
3383:   snes->gridsequence = steps;
3384:   return(0);
3385: }

3387: /*@
3388:    SNESGetGridSequence - gets the number of steps of grid sequencing that SNES does

3390:    Logically Collective on SNES

3392:    Input Parameter:
3393: .  snes - the SNES context

3395:    Output Parameter:
3396: .  steps - the number of refinements to do, defaults to 0

3398:    Options Database Keys:
3399: .    -snes_grid_sequence <steps>

3401:    Level: intermediate

3403:    Notes:
3404:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3406: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetGridSequence()

3408: @*/
3409: PetscErrorCode  SNESGetGridSequence(SNES snes,PetscInt *steps)
3410: {
3413:   *steps = snes->gridsequence;
3414:   return(0);
3415: }

3417: /*@
3418:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

3420:    Not Collective

3422:    Input Parameter:
3423: .  snes - the SNES context

3425:    Output Parameter:
3426: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3427:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3429:    Options Database Keys:
3430: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3431: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3432: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3433: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag

3435:    Notes:
3436:    The default is 1
3437:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3439:    Level: intermediate

3441: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner(), SNESSetLagJacobianPersists(), SNESSetLagPreconditionerPersists()

3443: @*/
3444: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
3445: {
3448:   *lag = snes->lagpreconditioner;
3449:   return(0);
3450: }

3452: /*@
3453:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
3454:      often the preconditioner is rebuilt.

3456:    Logically Collective on SNES

3458:    Input Parameters:
3459: +  snes - the SNES context
3460: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3461:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

3463:    Options Database Keys:
3464: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3465: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3466: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3467: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag.

3469:    Notes:
3470:    The default is 1
3471:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3472:    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
3473:    at the next Newton step but never again (unless it is reset to another value)

3475:    Level: intermediate

3477: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobianPersists(), SNESSetLagPreconditionerPersists()

3479: @*/
3480: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
3481: {
3484:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3485:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3487:   snes->lagjacobian = lag;
3488:   return(0);
3489: }

3491: /*@
3492:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

3494:    Not Collective

3496:    Input Parameter:
3497: .  snes - the SNES context

3499:    Output Parameter:
3500: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3501:          the Jacobian is built etc.

3503:    Notes:
3504:    The default is 1
3505:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1 or SNESSetLagJacobianPersists() was called.

3507:    Level: intermediate

3509: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner(), SNESSetLagJacobianPersists(), SNESSetLagPreconditionerPersists()

3511: @*/
3512: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
3513: {
3516:   *lag = snes->lagjacobian;
3517:   return(0);
3518: }

3520: /*@
3521:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

3523:    Logically collective on SNES

3525:    Input Parameter:
3526: +  snes - the SNES context
3527: -   flg - jacobian lagging persists if true

3529:    Options Database Keys:
3530: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3531: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3532: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3533: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag


3536:    Notes:
3537:     This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3538:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3539:    timesteps may present huge efficiency gains.

3541:    Level: developer

3543: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC(), SNESSetLagJacobianPersists()

3545: @*/
3546: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3547: {
3551:   snes->lagjac_persist = flg;
3552:   return(0);
3553: }

3555: /*@
3556:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple nonlinear solves

3558:    Logically Collective on SNES

3560:    Input Parameter:
3561: +  snes - the SNES context
3562: -   flg - preconditioner lagging persists if true

3564:    Options Database Keys:
3565: +    -snes_lag_jacobian_persists <true,false> - sets the persistence
3566: .    -snes_lag_jacobian <-2,1,2,...> - sets the lag
3567: .    -snes_lag_preconditioner_persists <true,false> - sets the persistence
3568: -    -snes_lag_preconditioner <-2,1,2,...> - sets the lag

3570:    Notes:
3571:     This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3572:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3573:    several timesteps may present huge efficiency gains.

3575:    Level: developer

3577: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC(), SNESSetLagPreconditioner()

3579: @*/
3580: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3581: {
3585:   snes->lagpre_persist = flg;
3586:   return(0);
3587: }

3589: /*@
3590:    SNESSetForceIteration - force SNESSolve() to take at least one iteration regardless of the initial residual norm

3592:    Logically Collective on SNES

3594:    Input Parameters:
3595: +  snes - the SNES context
3596: -  force - PETSC_TRUE require at least one iteration

3598:    Options Database Keys:
3599: .    -snes_force_iteration <force> - Sets forcing an iteration

3601:    Notes:
3602:    This is used sometimes with TS to prevent TS from detecting a false steady state solution

3604:    Level: intermediate

3606: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3607: @*/
3608: PetscErrorCode  SNESSetForceIteration(SNES snes,PetscBool force)
3609: {
3612:   snes->forceiteration = force;
3613:   return(0);
3614: }

3616: /*@
3617:    SNESGetForceIteration - Whether or not to force SNESSolve() take at least one iteration regardless of the initial residual norm

3619:    Logically Collective on SNES

3621:    Input Parameters:
3622: .  snes - the SNES context

3624:    Output Parameter:
3625: .  force - PETSC_TRUE requires at least one iteration.

3627:    Level: intermediate

3629: .seealso: SNESSetForceIteration(), SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3630: @*/
3631: PetscErrorCode  SNESGetForceIteration(SNES snes,PetscBool *force)
3632: {
3635:   *force = snes->forceiteration;
3636:   return(0);
3637: }

3639: /*@
3640:    SNESSetTolerances - Sets various parameters used in convergence tests.

3642:    Logically Collective on SNES

3644:    Input Parameters:
3645: +  snes - the SNES context
3646: .  abstol - absolute convergence tolerance
3647: .  rtol - relative convergence tolerance
3648: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3649: .  maxit - maximum number of iterations
3650: -  maxf - maximum number of function evaluations (-1 indicates no limit)

3652:    Options Database Keys:
3653: +    -snes_atol <abstol> - Sets abstol
3654: .    -snes_rtol <rtol> - Sets rtol
3655: .    -snes_stol <stol> - Sets stol
3656: .    -snes_max_it <maxit> - Sets maxit
3657: -    -snes_max_funcs <maxf> - Sets maxf

3659:    Notes:
3660:    The default maximum number of iterations is 50.
3661:    The default maximum number of function evaluations is 1000.

3663:    Level: intermediate

3665: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance(), SNESSetForceIteration()
3666: @*/
3667: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3668: {

3677:   if (abstol != PETSC_DEFAULT) {
3678:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3679:     snes->abstol = abstol;
3680:   }
3681:   if (rtol != PETSC_DEFAULT) {
3682:     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);
3683:     snes->rtol = rtol;
3684:   }
3685:   if (stol != PETSC_DEFAULT) {
3686:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3687:     snes->stol = stol;
3688:   }
3689:   if (maxit != PETSC_DEFAULT) {
3690:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3691:     snes->max_its = maxit;
3692:   }
3693:   if (maxf != PETSC_DEFAULT) {
3694:     if (maxf < -1) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be -1 or nonnegative",maxf);
3695:     snes->max_funcs = maxf;
3696:   }
3697:   snes->tolerancesset = PETSC_TRUE;
3698:   return(0);
3699: }

3701: /*@
3702:    SNESSetDivergenceTolerance - Sets the divergence tolerance used for the SNES divergence test.

3704:    Logically Collective on SNES

3706:    Input Parameters:
3707: +  snes - the SNES context
3708: -  divtol - the divergence tolerance. Use -1 to deactivate the test.

3710:    Options Database Keys:
3711: .    -snes_divergence_tolerance <divtol> - Sets divtol

3713:    Notes:
3714:    The default divergence tolerance is 1e4.

3716:    Level: intermediate

3718: .seealso: SNESSetTolerances(), SNESGetDivergenceTolerance
3719: @*/
3720: PetscErrorCode  SNESSetDivergenceTolerance(SNES snes,PetscReal divtol)
3721: {

3726:   if (divtol != PETSC_DEFAULT) {
3727:     snes->divtol = divtol;
3728:   }
3729:   else {
3730:     snes->divtol = 1.0e4;
3731:   }
3732:   return(0);
3733: }

3735: /*@
3736:    SNESGetTolerances - Gets various parameters used in convergence tests.

3738:    Not Collective

3740:    Input Parameters:
3741: +  snes - the SNES context
3742: .  atol - absolute convergence tolerance
3743: .  rtol - relative convergence tolerance
3744: .  stol -  convergence tolerance in terms of the norm
3745:            of the change in the solution between steps
3746: .  maxit - maximum number of iterations
3747: -  maxf - maximum number of function evaluations

3749:    Notes:
3750:    The user can specify NULL for any parameter that is not needed.

3752:    Level: intermediate

3754: .seealso: SNESSetTolerances()
3755: @*/
3756: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3757: {
3760:   if (atol)  *atol  = snes->abstol;
3761:   if (rtol)  *rtol  = snes->rtol;
3762:   if (stol)  *stol  = snes->stol;
3763:   if (maxit) *maxit = snes->max_its;
3764:   if (maxf)  *maxf  = snes->max_funcs;
3765:   return(0);
3766: }

3768: /*@
3769:    SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.

3771:    Not Collective

3773:    Input Parameters:
3774: +  snes - the SNES context
3775: -  divtol - divergence tolerance

3777:    Level: intermediate

3779: .seealso: SNESSetDivergenceTolerance()
3780: @*/
3781: PetscErrorCode  SNESGetDivergenceTolerance(SNES snes,PetscReal *divtol)
3782: {
3785:   if (divtol) *divtol = snes->divtol;
3786:   return(0);
3787: }

3789: /*@
3790:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3792:    Logically Collective on SNES

3794:    Input Parameters:
3795: +  snes - the SNES context
3796: -  tol - tolerance

3798:    Options Database Key:
3799: .  -snes_trtol <tol> - Sets tol

3801:    Level: intermediate

3803: .seealso: SNESSetTolerances()
3804: @*/
3805: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3806: {
3810:   snes->deltatol = tol;
3811:   return(0);
3812: }

3814: PETSC_INTERN PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);

3816: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3817: {
3818:   PetscDrawLG      lg;
3819:   PetscErrorCode   ierr;
3820:   PetscReal        x,y,per;
3821:   PetscViewer      v = (PetscViewer)monctx;
3822:   static PetscReal prev; /* should be in the context */
3823:   PetscDraw        draw;

3827:   PetscViewerDrawGetDrawLG(v,0,&lg);
3828:   if (!n) {PetscDrawLGReset(lg);}
3829:   PetscDrawLGGetDraw(lg,&draw);
3830:   PetscDrawSetTitle(draw,"Residual norm");
3831:   x    = (PetscReal)n;
3832:   if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3833:   else y = -15.0;
3834:   PetscDrawLGAddPoint(lg,&x,&y);
3835:   if (n < 20 || !(n % 5) || snes->reason) {
3836:     PetscDrawLGDraw(lg);
3837:     PetscDrawLGSave(lg);
3838:   }

3840:   PetscViewerDrawGetDrawLG(v,1,&lg);
3841:   if (!n) {PetscDrawLGReset(lg);}
3842:   PetscDrawLGGetDraw(lg,&draw);
3843:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3844:    SNESMonitorRange_Private(snes,n,&per);
3845:   x    = (PetscReal)n;
3846:   y    = 100.0*per;
3847:   PetscDrawLGAddPoint(lg,&x,&y);
3848:   if (n < 20 || !(n % 5) || snes->reason) {
3849:     PetscDrawLGDraw(lg);
3850:     PetscDrawLGSave(lg);
3851:   }

3853:   PetscViewerDrawGetDrawLG(v,2,&lg);
3854:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3855:   PetscDrawLGGetDraw(lg,&draw);
3856:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3857:   x    = (PetscReal)n;
3858:   y    = (prev - rnorm)/prev;
3859:   PetscDrawLGAddPoint(lg,&x,&y);
3860:   if (n < 20 || !(n % 5) || snes->reason) {
3861:     PetscDrawLGDraw(lg);
3862:     PetscDrawLGSave(lg);
3863:   }

3865:   PetscViewerDrawGetDrawLG(v,3,&lg);
3866:   if (!n) {PetscDrawLGReset(lg);}
3867:   PetscDrawLGGetDraw(lg,&draw);
3868:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3869:   x    = (PetscReal)n;
3870:   y    = (prev - rnorm)/(prev*per);
3871:   if (n > 2) { /*skip initial crazy value */
3872:     PetscDrawLGAddPoint(lg,&x,&y);
3873:   }
3874:   if (n < 20 || !(n % 5) || snes->reason) {
3875:     PetscDrawLGDraw(lg);
3876:     PetscDrawLGSave(lg);
3877:   }
3878:   prev = rnorm;
3879:   return(0);
3880: }

3882: /*@
3883:    SNESMonitor - runs the user provided monitor routines, if they exist

3885:    Collective on SNES

3887:    Input Parameters:
3888: +  snes - nonlinear solver context obtained from SNESCreate()
3889: .  iter - iteration number
3890: -  rnorm - relative norm of the residual

3892:    Notes:
3893:    This routine is called by the SNES implementations.
3894:    It does not typically need to be called by the user.

3896:    Level: developer

3898: .seealso: SNESMonitorSet()
3899: @*/
3900: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3901: {
3903:   PetscInt       i,n = snes->numbermonitors;

3906:   VecLockReadPush(snes->vec_sol);
3907:   for (i=0; i<n; i++) {
3908:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3909:   }
3910:   VecLockReadPop(snes->vec_sol);
3911:   return(0);
3912: }

3914: /* ------------ Routines to set performance monitoring options ----------- */

3916: /*MC
3917:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3919:      Synopsis:
3920: #include <petscsnes.h>
3921: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3923:      Collective on snes

3925:     Input Parameters:
3926: +    snes - the SNES context
3927: .    its - iteration number
3928: .    norm - 2-norm function value (may be estimated)
3929: -    mctx - [optional] monitoring context

3931:    Level: advanced

3933: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3934: M*/

3936: /*@C
3937:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3938:    iteration of the nonlinear solver to display the iteration's
3939:    progress.

3941:    Logically Collective on SNES

3943:    Input Parameters:
3944: +  snes - the SNES context
3945: .  f - the monitor function, see SNESMonitorFunction for the calling sequence
3946: .  mctx - [optional] user-defined context for private data for the
3947:           monitor routine (use NULL if no context is desired)
3948: -  monitordestroy - [optional] routine that frees monitor context
3949:           (may be NULL)

3951:    Options Database Keys:
3952: +    -snes_monitor        - sets SNESMonitorDefault()
3953: .    -snes_monitor draw::draw_lg - sets line graph monitor,
3954: -    -snes_monitor_cancel - cancels all monitors that have
3955:                             been hardwired into a code by
3956:                             calls to SNESMonitorSet(), but
3957:                             does not cancel those set via
3958:                             the options database.

3960:    Notes:
3961:    Several different monitoring routines may be set by calling
3962:    SNESMonitorSet() multiple times; all will be called in the
3963:    order in which they were set.

3965:    Fortran Notes:
3966:     Only a single monitor function can be set for each SNES object

3968:    Level: intermediate

3970: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3971: @*/
3972: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*f)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3973: {
3974:   PetscInt       i;
3976:   PetscBool      identical;

3980:   for (i=0; i<snes->numbermonitors;i++) {
3981:     PetscMonitorCompare((PetscErrorCode (*)(void))f,mctx,monitordestroy,(PetscErrorCode (*)(void))snes->monitor[i],snes->monitorcontext[i],snes->monitordestroy[i],&identical);
3982:     if (identical) return(0);
3983:   }
3984:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3985:   snes->monitor[snes->numbermonitors]          = f;
3986:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3987:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3988:   return(0);
3989: }

3991: /*@
3992:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3994:    Logically Collective on SNES

3996:    Input Parameters:
3997: .  snes - the SNES context

3999:    Options Database Key:
4000: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
4001:     into a code by calls to SNESMonitorSet(), but does not cancel those
4002:     set via the options database

4004:    Notes:
4005:    There is no way to clear one specific monitor from a SNES object.

4007:    Level: intermediate

4009: .seealso: SNESMonitorDefault(), SNESMonitorSet()
4010: @*/
4011: PetscErrorCode  SNESMonitorCancel(SNES snes)
4012: {
4014:   PetscInt       i;

4018:   for (i=0; i<snes->numbermonitors; i++) {
4019:     if (snes->monitordestroy[i]) {
4020:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
4021:     }
4022:   }
4023:   snes->numbermonitors = 0;
4024:   return(0);
4025: }

4027: /*MC
4028:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

4030:      Synopsis:
4031: #include <petscsnes.h>
4032: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

4034:      Collective on snes

4036:     Input Parameters:
4037: +    snes - the SNES context
4038: .    it - current iteration (0 is the first and is before any Newton step)
4039: .    xnorm - 2-norm of current iterate
4040: .    gnorm - 2-norm of current step
4041: .    f - 2-norm of function
4042: -    cctx - [optional] convergence context

4044:     Output Parameter:
4045: .    reason - reason for convergence/divergence, only needs to be set when convergence or divergence is detected

4047:    Level: intermediate

4049: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
4050: M*/

4052: /*@C
4053:    SNESSetConvergenceTest - Sets the function that is to be used
4054:    to test for convergence of the nonlinear iterative solution.

4056:    Logically Collective on SNES

4058:    Input Parameters:
4059: +  snes - the SNES context
4060: .  SNESConvergenceTestFunction - routine to test for convergence
4061: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
4062: -  destroy - [optional] destructor for the context (may be NULL; PETSC_NULL_FUNCTION in Fortran)

4064:    Level: advanced

4066: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
4067: @*/
4068: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
4069: {

4074:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
4075:   if (snes->ops->convergeddestroy) {
4076:     (*snes->ops->convergeddestroy)(snes->cnvP);
4077:   }
4078:   snes->ops->converged        = SNESConvergenceTestFunction;
4079:   snes->ops->convergeddestroy = destroy;
4080:   snes->cnvP                  = cctx;
4081:   return(0);
4082: }

4084: /*@
4085:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

4087:    Not Collective

4089:    Input Parameter:
4090: .  snes - the SNES context

4092:    Output Parameter:
4093: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
4094:             manual pages for the individual convergence tests for complete lists

4096:    Options Database:
4097: .   -snes_converged_reason - prints the reason to standard out

4099:    Level: intermediate

4101:    Notes:
4102:     Should only be called after the call the SNESSolve() is complete, if it is called earlier it returns the value SNES__CONVERGED_ITERATING.

4104: .seealso: SNESSetConvergenceTest(), SNESSetConvergedReason(), SNESConvergedReason
4105: @*/
4106: PetscErrorCode SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
4107: {
4111:   *reason = snes->reason;
4112:   return(0);
4113: }

4115: /*@C
4116:    SNESGetConvergedReasonString - Return a human readable string for snes converged reason

4118:    Not Collective

4120:    Input Parameter:
4121: .  snes - the SNES context

4123:    Output Parameter:
4124: .  strreason - a human readable string that describes SNES converged reason

4126:    Level: beginner

4128: .seealso: SNESGetConvergedReason()
4129: @*/
4130: PetscErrorCode SNESGetConvergedReasonString(SNES snes, const char** strreason)
4131: {
4135:   *strreason = SNESConvergedReasons[snes->reason];
4136:   return(0);
4137: }

4139: /*@
4140:    SNESSetConvergedReason - Sets the reason the SNES iteration was stopped.

4142:    Not Collective

4144:    Input Parameters:
4145: +  snes - the SNES context
4146: -  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
4147:             manual pages for the individual convergence tests for complete lists

4149:    Level: intermediate

4151: .seealso: SNESGetConvergedReason(), SNESSetConvergenceTest(), SNESConvergedReason
4152: @*/
4153: PetscErrorCode SNESSetConvergedReason(SNES snes,SNESConvergedReason reason)
4154: {
4157:   snes->reason = reason;
4158:   return(0);
4159: }

4161: /*@
4162:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

4164:    Logically Collective on SNES

4166:    Input Parameters:
4167: +  snes - iterative context obtained from SNESCreate()
4168: .  a   - array to hold history, this array will contain the function norms computed at each step
4169: .  its - integer array holds the number of linear iterations for each solve.
4170: .  na  - size of a and its
4171: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
4172:            else it continues storing new values for new nonlinear solves after the old ones

4174:    Notes:
4175:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
4176:    default array of length 10000 is allocated.

4178:    This routine is useful, e.g., when running a code for purposes
4179:    of accurate performance monitoring, when no I/O should be done
4180:    during the section of code that is being timed.

4182:    Level: intermediate

4184: .seealso: SNESGetConvergenceHistory()

4186: @*/
4187: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
4188: {

4195:   if (!a) {
4196:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
4197:     PetscCalloc2(na,&a,na,&its);
4198:     snes->conv_hist_alloc = PETSC_TRUE;
4199:   }
4200:   snes->conv_hist       = a;
4201:   snes->conv_hist_its   = its;
4202:   snes->conv_hist_max   = na;
4203:   snes->conv_hist_len   = 0;
4204:   snes->conv_hist_reset = reset;
4205:   return(0);
4206: }

4208: #if defined(PETSC_HAVE_MATLAB_ENGINE)
4209: #include <engine.h>   /* MATLAB include file */
4210: #include <mex.h>      /* MATLAB include file */

4212: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4213: {
4214:   mxArray   *mat;
4215:   PetscInt  i;
4216:   PetscReal *ar;

4219:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
4220:   ar  = (PetscReal*) mxGetData(mat);
4221:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4222:   PetscFunctionReturn(mat);
4223: }
4224: #endif

4226: /*@C
4227:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

4229:    Not Collective

4231:    Input Parameter:
4232: .  snes - iterative context obtained from SNESCreate()

4234:    Output Parameters:
4235: +  a   - array to hold history
4236: .  its - integer array holds the number of linear iterations (or
4237:          negative if not converged) for each solve.
4238: -  na  - size of a and its

4240:    Notes:
4241:     The calling sequence for this routine in Fortran is
4242: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

4244:    This routine is useful, e.g., when running a code for purposes
4245:    of accurate performance monitoring, when no I/O should be done
4246:    during the section of code that is being timed.

4248:    Level: intermediate

4250: .seealso: SNESSetConvergenceHistory()

4252: @*/
4253: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
4254: {
4257:   if (a)   *a   = snes->conv_hist;
4258:   if (its) *its = snes->conv_hist_its;
4259:   if (na)  *na  = snes->conv_hist_len;
4260:   return(0);
4261: }

4263: /*@C
4264:   SNESSetUpdate - Sets the general-purpose update function called
4265:   at the beginning of every iteration of the nonlinear solve. Specifically
4266:   it is called just before the Jacobian is "evaluated".

4268:   Logically Collective on SNES

4270:   Input Parameters:
4271: + snes - The nonlinear solver context
4272: - func - The function

4274:   Calling sequence of func:
4275: $ func (SNES snes, PetscInt step);

4277: . step - The current step of the iteration

4279:   Level: advanced

4281:   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()
4282:         This is not used by most users.

4284: .seealso SNESSetJacobian(), SNESSolve()
4285: @*/
4286: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
4287: {
4290:   snes->ops->update = func;
4291:   return(0);
4292: }

4294: /*
4295:    SNESScaleStep_Private - Scales a step so that its length is less than the
4296:    positive parameter delta.

4298:     Input Parameters:
4299: +   snes - the SNES context
4300: .   y - approximate solution of linear system
4301: .   fnorm - 2-norm of current function
4302: -   delta - trust region size

4304:     Output Parameters:
4305: +   gpnorm - predicted function norm at the new point, assuming local
4306:     linearization.  The value is zero if the step lies within the trust
4307:     region, and exceeds zero otherwise.
4308: -   ynorm - 2-norm of the step

4310:     Note:
4311:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
4312:     is set to be the maximum allowable step size.

4314: */
4315: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
4316: {
4317:   PetscReal      nrm;
4318:   PetscScalar    cnorm;


4326:   VecNorm(y,NORM_2,&nrm);
4327:   if (nrm > *delta) {
4328:     nrm     = *delta/nrm;
4329:     *gpnorm = (1.0 - nrm)*(*fnorm);
4330:     cnorm   = nrm;
4331:     VecScale(y,cnorm);
4332:     *ynorm  = *delta;
4333:   } else {
4334:     *gpnorm = 0.0;
4335:     *ynorm  = nrm;
4336:   }
4337:   return(0);
4338: }

4340: /*@C
4341:    SNESConvergedReasonView - Displays the reason a SNES solve converged or diverged to a viewer

4343:    Collective on SNES

4345:    Parameter:
4346: +  snes - iterative context obtained from SNESCreate()
4347: -  viewer - the viewer to display the reason


4350:    Options Database Keys:
4351: +  -snes_converged_reason - print reason for converged or diverged, also prints number of iterations
4352: -  -snes_converged_reason ::failed - only print reason and number of iterations when diverged

4354:   Notes:
4355:      To change the format of the output call PetscViewerPushFormat(viewer,format) before this call. Use PETSC_VIEWER_DEFAULT for the default,
4356:      use PETSC_VIEWER_FAILED to only display a reason if it fails.

4358:    Level: beginner

4360: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault(), SNESGetConvergedReason(), SNESConvergedReasonViewFromOptions(),
4361:           PetscViewerPushFormat(), PetscViewerPopFormat()

4363: @*/
4364: PetscErrorCode  SNESConvergedReasonView(SNES snes,PetscViewer viewer)
4365: {
4366:   PetscViewerFormat format;
4367:   PetscBool         isAscii;
4368:   PetscErrorCode    ierr;

4371:   if (!viewer) viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
4372:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isAscii);
4373:   if (isAscii) {
4374:     PetscViewerGetFormat(viewer, &format);
4375:     PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);
4376:     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4377:       DM              dm;
4378:       Vec             u;
4379:       PetscDS         prob;
4380:       PetscInt        Nf, f;
4381:       PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4382:       void            **exactCtx;
4383:       PetscReal       error;

4385:       SNESGetDM(snes, &dm);
4386:       SNESGetSolution(snes, &u);
4387:       DMGetDS(dm, &prob);
4388:       PetscDSGetNumFields(prob, &Nf);
4389:       PetscMalloc2(Nf, &exactSol, Nf, &exactCtx);
4390:       for (f = 0; f < Nf; ++f) {PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]);}
4391:       DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error);
4392:       PetscFree2(exactSol, exactCtx);
4393:       if (error < 1.0e-11) {PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n");}
4394:       else                 {PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", error);}
4395:     }
4396:     if (snes->reason > 0 && format != PETSC_VIEWER_FAILED) {
4397:       if (((PetscObject) snes)->prefix) {
4398:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve converged due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4399:       } else {
4400:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4401:       }
4402:     } else if (snes->reason <= 0) {
4403:       if (((PetscObject) snes)->prefix) {
4404:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve did not converge due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4405:       } else {
4406:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4407:       }
4408:     }
4409:     PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);
4410:   }
4411:   return(0);
4412: }

4414: /*@C
4415:    SNESConvergedReasonViewSet - Sets an ADDITIONAL function that is to be used at the
4416:     end of the nonlinear solver to display the conver reason of the nonlinear solver.

4418:    Logically Collective on SNES

4420:    Input Parameters:
4421: +  snes - the SNES context
4422: .  f - the snes converged reason view function
4423: .  vctx - [optional] user-defined context for private data for the
4424:           snes converged reason view routine (use NULL if no context is desired)
4425: -  reasonviewdestroy - [optional] routine that frees reasonview context
4426:           (may be NULL)

4428:    Options Database Keys:
4429: +    -snes_converged_reason        - sets a default SNESConvergedReasonView()
4430: -    -snes_converged_reason_view_cancel - cancels all converged reason viewers that have
4431:                             been hardwired into a code by
4432:                             calls to SNESConvergedReasonViewSet(), but
4433:                             does not cancel those set via
4434:                             the options database.

4436:    Notes:
4437:    Several different converged reason view routines may be set by calling
4438:    SNESConvergedReasonViewSet() multiple times; all will be called in the
4439:    order in which they were set.

4441:    Level: intermediate

4443: .seealso: SNESConvergedReasonView(), SNESConvergedReasonViewCancel()
4444: @*/
4445: PetscErrorCode  SNESConvergedReasonViewSet(SNES snes,PetscErrorCode (*f)(SNES,void*),void *vctx,PetscErrorCode (*reasonviewdestroy)(void**))
4446: {
4447:   PetscInt       i;
4449:   PetscBool      identical;

4453:   for (i=0; i<snes->numberreasonviews;i++) {
4454:     PetscMonitorCompare((PetscErrorCode (*)(void))f,vctx,reasonviewdestroy,(PetscErrorCode (*)(void))snes->reasonview[i],snes->reasonviewcontext[i],snes->reasonviewdestroy[i],&identical);
4455:     if (identical) return(0);
4456:   }
4457:   if (snes->numberreasonviews >= MAXSNESREASONVIEWS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many SNES reasonview set");
4458:   snes->reasonview[snes->numberreasonviews]          = f;
4459:   snes->reasonviewdestroy[snes->numberreasonviews]   = reasonviewdestroy;
4460:   snes->reasonviewcontext[snes->numberreasonviews++] = (void*)vctx;
4461:   return(0);
4462: }

4464: /*@
4465:   SNESConvergedReasonViewFromOptions - Processes command line options to determine if/how a SNESReason is to be viewed.
4466:                                        All the user-provided convergedReasonView routines will be involved as well, if they exist.

4468:   Collective on SNES

4470:   Input Parameters:
4471: . snes   - the SNES object

4473:   Level: intermediate

4475: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault(), SNESGetConvergedReason(), SNESConvergedReasonView()

4477: @*/
4478: PetscErrorCode SNESConvergedReasonViewFromOptions(SNES snes)
4479: {
4480:   PetscErrorCode    ierr;
4481:   PetscViewer       viewer;
4482:   PetscBool         flg;
4483:   static PetscBool  incall = PETSC_FALSE;
4484:   PetscViewerFormat format;
4485:   PetscInt          i;

4488:   if (incall) return(0);
4489:   incall = PETSC_TRUE;

4491:   /* All user-provided viewers are called first, if they exist. */
4492:   for (i=0; i<snes->numberreasonviews; i++) {
4493:     (*snes->reasonview[i])(snes,snes->reasonviewcontext[i]);
4494:   }

4496:   /* Call PETSc default routine if users ask for it */
4497:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_converged_reason",&viewer,&format,&flg);
4498:   if (flg) {
4499:     PetscViewerPushFormat(viewer,format);
4500:     SNESConvergedReasonView(snes,viewer);
4501:     PetscViewerPopFormat(viewer);
4502:     PetscViewerDestroy(&viewer);
4503:   }
4504:   incall = PETSC_FALSE;
4505:   return(0);
4506: }

4508: /*@
4509:    SNESSolve - Solves a nonlinear system F(x) = b.
4510:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

4512:    Collective on SNES

4514:    Input Parameters:
4515: +  snes - the SNES context
4516: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
4517: -  x - the solution vector.

4519:    Notes:
4520:    The user should initialize the vector,x, with the initial guess
4521:    for the nonlinear solve prior to calling SNESSolve.  In particular,
4522:    to employ an initial guess of zero, the user should explicitly set
4523:    this vector to zero by calling VecSet().

4525:    Level: beginner

4527: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
4528: @*/
4529: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
4530: {
4531:   PetscErrorCode    ierr;
4532:   PetscBool         flg;
4533:   PetscInt          grid;
4534:   Vec               xcreated = NULL;
4535:   DM                dm;


4544:   /* High level operations using the nonlinear solver */
4545:   {
4546:     PetscViewer       viewer;
4547:     PetscViewerFormat format;
4548:     PetscInt          num;
4549:     PetscBool         flg;
4550:     static PetscBool  incall = PETSC_FALSE;

4552:     if (!incall) {
4553:       /* Estimate the convergence rate of the discretization */
4554:       PetscOptionsGetViewer(PetscObjectComm((PetscObject) snes),((PetscObject)snes)->options, ((PetscObject) snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg);
4555:       if (flg) {
4556:         PetscConvEst conv;
4557:         DM           dm;
4558:         PetscReal   *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4559:         PetscInt     Nf;

4561:         incall = PETSC_TRUE;
4562:         SNESGetDM(snes, &dm);
4563:         DMGetNumFields(dm, &Nf);
4564:         PetscCalloc1(Nf, &alpha);
4565:         PetscConvEstCreate(PetscObjectComm((PetscObject) snes), &conv);
4566:         PetscConvEstSetSolver(conv, (PetscObject) snes);
4567:         PetscConvEstSetFromOptions(conv);
4568:         PetscConvEstSetUp(conv);
4569:         PetscConvEstGetConvRate(conv, alpha);
4570:         PetscViewerPushFormat(viewer, format);
4571:         PetscConvEstRateView(conv, alpha, viewer);
4572:         PetscViewerPopFormat(viewer);
4573:         PetscViewerDestroy(&viewer);
4574:         PetscConvEstDestroy(&conv);
4575:         PetscFree(alpha);
4576:         incall = PETSC_FALSE;
4577:       }
4578:       /* Adaptively refine the initial grid */
4579:       num  = 1;
4580:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_initial", &num, &flg);
4581:       if (flg) {
4582:         DMAdaptor adaptor;

4584:         incall = PETSC_TRUE;
4585:         DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor);
4586:         DMAdaptorSetSolver(adaptor, snes);
4587:         DMAdaptorSetSequenceLength(adaptor, num);
4588:         DMAdaptorSetFromOptions(adaptor);
4589:         DMAdaptorSetUp(adaptor);
4590:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x);
4591:         DMAdaptorDestroy(&adaptor);
4592:         incall = PETSC_FALSE;
4593:       }
4594:       /* Use grid sequencing to adapt */
4595:       num  = 0;
4596:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_sequence", &num, NULL);
4597:       if (num) {
4598:         DMAdaptor adaptor;

4600:         incall = PETSC_TRUE;
4601:         DMAdaptorCreate(PetscObjectComm((PetscObject)snes), &adaptor);
4602:         DMAdaptorSetSolver(adaptor, snes);
4603:         DMAdaptorSetSequenceLength(adaptor, num);
4604:         DMAdaptorSetFromOptions(adaptor);
4605:         DMAdaptorSetUp(adaptor);
4606:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x);
4607:         DMAdaptorDestroy(&adaptor);
4608:         incall = PETSC_FALSE;
4609:       }
4610:     }
4611:   }
4612:   if (!x) {
4613:     SNESGetDM(snes,&dm);
4614:     DMCreateGlobalVector(dm,&xcreated);
4615:     x    = xcreated;
4616:   }
4617:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

4619:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
4620:   for (grid=0; grid<snes->gridsequence+1; grid++) {

4622:     /* set solution vector */
4623:     if (!grid) {PetscObjectReference((PetscObject)x);}
4624:     VecDestroy(&snes->vec_sol);
4625:     snes->vec_sol = x;
4626:     SNESGetDM(snes,&dm);

4628:     /* set affine vector if provided */
4629:     if (b) { PetscObjectReference((PetscObject)b); }
4630:     VecDestroy(&snes->vec_rhs);
4631:     snes->vec_rhs = b;

4633:     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");
4634:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
4635:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
4636:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
4637:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
4638:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
4639:     }
4640:     DMShellSetGlobalVector(dm,snes->vec_sol);
4641:     SNESSetUp(snes);

4643:     if (!grid) {
4644:       if (snes->ops->computeinitialguess) {
4645:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
4646:       }
4647:     }

4649:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4650:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

4652:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
4653:     (*snes->ops->solve)(snes);
4654:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
4655:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");
4656:     snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */

4658:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4659:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

4661:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_test_local_min",NULL,NULL,&flg);
4662:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
4663:     /* Call converged reason views. This may involve user-provided viewers as well */
4664:     SNESConvergedReasonViewFromOptions(snes);

4666:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
4667:     if (snes->reason < 0) break;
4668:     if (grid <  snes->gridsequence) {
4669:       DM  fine;
4670:       Vec xnew;
4671:       Mat interp;

4673:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
4674:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
4675:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
4676:       DMCreateGlobalVector(fine,&xnew);
4677:       MatInterpolate(interp,x,xnew);
4678:       DMInterpolate(snes->dm,interp,fine);
4679:       MatDestroy(&interp);
4680:       x    = xnew;

4682:       SNESReset(snes);
4683:       SNESSetDM(snes,fine);
4684:       SNESResetFromOptions(snes);
4685:       DMDestroy(&fine);
4686:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
4687:     }
4688:   }
4689:   SNESViewFromOptions(snes,NULL,"-snes_view");
4690:   VecViewFromOptions(snes->vec_sol,(PetscObject)snes,"-snes_view_solution");
4691:   DMMonitor(snes->dm);

4693:   VecDestroy(&xcreated);
4694:   PetscObjectSAWsBlock((PetscObject)snes);
4695:   return(0);
4696: }

4698: /* --------- Internal routines for SNES Package --------- */

4700: /*@C
4701:    SNESSetType - Sets the method for the nonlinear solver.

4703:    Collective on SNES

4705:    Input Parameters:
4706: +  snes - the SNES context
4707: -  type - a known method

4709:    Options Database Key:
4710: .  -snes_type <type> - Sets the method; use -help for a list
4711:    of available methods (for instance, newtonls or newtontr)

4713:    Notes:
4714:    See "petsc/include/petscsnes.h" for available methods (for instance)
4715: +    SNESNEWTONLS - Newton's method with line search
4716:      (systems of nonlinear equations)
4717: -    SNESNEWTONTR - Newton's method with trust region
4718:      (systems of nonlinear equations)

4720:   Normally, it is best to use the SNESSetFromOptions() command and then
4721:   set the SNES solver type from the options database rather than by using
4722:   this routine.  Using the options database provides the user with
4723:   maximum flexibility in evaluating the many nonlinear solvers.
4724:   The SNESSetType() routine is provided for those situations where it
4725:   is necessary to set the nonlinear solver independently of the command
4726:   line or options database.  This might be the case, for example, when
4727:   the choice of solver changes during the execution of the program,
4728:   and the user's application is taking responsibility for choosing the
4729:   appropriate method.

4731:     Developer Notes:
4732:     SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
4733:     the constructor in that list and calls it to create the spexific object.

4735:   Level: intermediate

4737: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

4739: @*/
4740: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
4741: {
4742:   PetscErrorCode ierr,(*r)(SNES);
4743:   PetscBool      match;


4749:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
4750:   if (match) return(0);

4752:   PetscFunctionListFind(SNESList,type,&r);
4753:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
4754:   /* Destroy the previous private SNES context */
4755:   if (snes->ops->destroy) {
4756:     (*(snes)->ops->destroy)(snes);
4757:     snes->ops->destroy = NULL;
4758:   }
4759:   /* Reinitialize function pointers in SNESOps structure */
4760:   snes->ops->setup          = NULL;
4761:   snes->ops->solve          = NULL;
4762:   snes->ops->view           = NULL;
4763:   snes->ops->setfromoptions = NULL;
4764:   snes->ops->destroy        = NULL;

4766:   /* It may happen the user has customized the line search before calling SNESSetType */
4767:   if (((PetscObject)snes)->type_name) {
4768:     SNESLineSearchDestroy(&snes->linesearch);
4769:   }

4771:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4772:   snes->setupcalled = PETSC_FALSE;

4774:   PetscObjectChangeTypeName((PetscObject)snes,type);
4775:   (*r)(snes);
4776:   return(0);
4777: }

4779: /*@C
4780:    SNESGetType - Gets the SNES method type and name (as a string).

4782:    Not Collective

4784:    Input Parameter:
4785: .  snes - nonlinear solver context

4787:    Output Parameter:
4788: .  type - SNES method (a character string)

4790:    Level: intermediate

4792: @*/
4793: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
4794: {
4798:   *type = ((PetscObject)snes)->type_name;
4799:   return(0);
4800: }

4802: /*@
4803:   SNESSetSolution - Sets the solution vector for use by the SNES routines.

4805:   Logically Collective on SNES

4807:   Input Parameters:
4808: + snes - the SNES context obtained from SNESCreate()
4809: - u    - the solution vector

4811:   Level: beginner

4813: @*/
4814: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4815: {
4816:   DM             dm;

4822:   PetscObjectReference((PetscObject) u);
4823:   VecDestroy(&snes->vec_sol);

4825:   snes->vec_sol = u;

4827:   SNESGetDM(snes, &dm);
4828:   DMShellSetGlobalVector(dm, u);
4829:   return(0);
4830: }

4832: /*@
4833:    SNESGetSolution - Returns the vector where the approximate solution is
4834:    stored. This is the fine grid solution when using SNESSetGridSequence().

4836:    Not Collective, but Vec is parallel if SNES is parallel

4838:    Input Parameter:
4839: .  snes - the SNES context

4841:    Output Parameter:
4842: .  x - the solution

4844:    Level: intermediate

4846: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
4847: @*/
4848: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
4849: {
4853:   *x = snes->vec_sol;
4854:   return(0);
4855: }

4857: /*@
4858:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4859:    stored.

4861:    Not Collective, but Vec is parallel if SNES is parallel

4863:    Input Parameter:
4864: .  snes - the SNES context

4866:    Output Parameter:
4867: .  x - the solution update

4869:    Level: advanced

4871: .seealso: SNESGetSolution(), SNESGetFunction()
4872: @*/
4873: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4874: {
4878:   *x = snes->vec_sol_update;
4879:   return(0);
4880: }

4882: /*@C
4883:    SNESGetFunction - Returns the vector where the function is stored.

4885:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4887:    Input Parameter:
4888: .  snes - the SNES context

4890:    Output Parameter:
4891: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4892: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4893: -  ctx - the function context (or NULL if you don't want it)

4895:    Level: advanced

4897:     Notes: The vector r DOES NOT, in general contain the current value of the SNES nonlinear function

4899: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4900: @*/
4901: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4902: {
4904:   DM             dm;

4908:   if (r) {
4909:     if (!snes->vec_func) {
4910:       if (snes->vec_rhs) {
4911:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4912:       } else if (snes->vec_sol) {
4913:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4914:       } else if (snes->dm) {
4915:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4916:       }
4917:     }
4918:     *r = snes->vec_func;
4919:   }
4920:   SNESGetDM(snes,&dm);
4921:   DMSNESGetFunction(dm,f,ctx);
4922:   return(0);
4923: }

4925: /*@C
4926:    SNESGetNGS - Returns the NGS function and context.

4928:    Input Parameter:
4929: .  snes - the SNES context

4931:    Output Parameter:
4932: +  f - the function (or NULL) see SNESNGSFunction for details
4933: -  ctx    - the function context (or NULL)

4935:    Level: advanced

4937: .seealso: SNESSetNGS(), SNESGetFunction()
4938: @*/

4940: PetscErrorCode SNESGetNGS (SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void*), void ** ctx)
4941: {
4943:   DM             dm;

4947:   SNESGetDM(snes,&dm);
4948:   DMSNESGetNGS(dm,f,ctx);
4949:   return(0);
4950: }

4952: /*@C
4953:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4954:    SNES options in the database.

4956:    Logically Collective on SNES

4958:    Input Parameter:
4959: +  snes - the SNES context
4960: -  prefix - the prefix to prepend to all option names

4962:    Notes:
4963:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4964:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4966:    Level: advanced

4968: .seealso: SNESSetFromOptions()
4969: @*/
4970: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4971: {

4976:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4977:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4978:   if (snes->linesearch) {
4979:     SNESGetLineSearch(snes,&snes->linesearch);
4980:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4981:   }
4982:   KSPSetOptionsPrefix(snes->ksp,prefix);
4983:   return(0);
4984: }

4986: /*@C
4987:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4988:    SNES options in the database.

4990:    Logically Collective on SNES

4992:    Input Parameters:
4993: +  snes - the SNES context
4994: -  prefix - the prefix to prepend to all option names

4996:    Notes:
4997:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4998:    The first character of all runtime options is AUTOMATICALLY the hyphen.

5000:    Level: advanced

5002: .seealso: SNESGetOptionsPrefix()
5003: @*/
5004: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
5005: {

5010:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
5011:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
5012:   if (snes->linesearch) {
5013:     SNESGetLineSearch(snes,&snes->linesearch);
5014:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
5015:   }
5016:   KSPAppendOptionsPrefix(snes->ksp,prefix);
5017:   return(0);
5018: }

5020: /*@C
5021:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
5022:    SNES options in the database.

5024:    Not Collective

5026:    Input Parameter:
5027: .  snes - the SNES context

5029:    Output Parameter:
5030: .  prefix - pointer to the prefix string used

5032:    Notes:
5033:     On the fortran side, the user should pass in a string 'prefix' of
5034:    sufficient length to hold the prefix.

5036:    Level: advanced

5038: .seealso: SNESAppendOptionsPrefix()
5039: @*/
5040: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
5041: {

5046:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
5047:   return(0);
5048: }


5051: /*@C
5052:   SNESRegister - Adds a method to the nonlinear solver package.

5054:    Not collective

5056:    Input Parameters:
5057: +  name_solver - name of a new user-defined solver
5058: -  routine_create - routine to create method context

5060:    Notes:
5061:    SNESRegister() may be called multiple times to add several user-defined solvers.

5063:    Sample usage:
5064: .vb
5065:    SNESRegister("my_solver",MySolverCreate);
5066: .ve

5068:    Then, your solver can be chosen with the procedural interface via
5069: $     SNESSetType(snes,"my_solver")
5070:    or at runtime via the option
5071: $     -snes_type my_solver

5073:    Level: advanced

5075:     Note: If your function is not being put into a shared library then use SNESRegister() instead

5077: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

5079:   Level: advanced
5080: @*/
5081: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
5082: {

5086:   SNESInitializePackage();
5087:   PetscFunctionListAdd(&SNESList,sname,function);
5088:   return(0);
5089: }

5091: PetscErrorCode  SNESTestLocalMin(SNES snes)
5092: {
5094:   PetscInt       N,i,j;
5095:   Vec            u,uh,fh;
5096:   PetscScalar    value;
5097:   PetscReal      norm;

5100:   SNESGetSolution(snes,&u);
5101:   VecDuplicate(u,&uh);
5102:   VecDuplicate(u,&fh);

5104:   /* currently only works for sequential */
5105:   PetscPrintf(PetscObjectComm((PetscObject)snes),"Testing FormFunction() for local min\n");
5106:   VecGetSize(u,&N);
5107:   for (i=0; i<N; i++) {
5108:     VecCopy(u,uh);
5109:     PetscPrintf(PetscObjectComm((PetscObject)snes),"i = %D\n",i);
5110:     for (j=-10; j<11; j++) {
5111:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
5112:       VecSetValue(uh,i,value,ADD_VALUES);
5113:       SNESComputeFunction(snes,uh,fh);
5114:       VecNorm(fh,NORM_2,&norm);
5115:       PetscPrintf(PetscObjectComm((PetscObject)snes),"       j norm %D %18.16e\n",j,norm);
5116:       value = -value;
5117:       VecSetValue(uh,i,value,ADD_VALUES);
5118:     }
5119:   }
5120:   VecDestroy(&uh);
5121:   VecDestroy(&fh);
5122:   return(0);
5123: }

5125: /*@
5126:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
5127:    computing relative tolerance for linear solvers within an inexact
5128:    Newton method.

5130:    Logically Collective on SNES

5132:    Input Parameters:
5133: +  snes - SNES context
5134: -  flag - PETSC_TRUE or PETSC_FALSE

5136:     Options Database:
5137: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
5138: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
5139: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
5140: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
5141: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
5142: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
5143: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
5144: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

5146:    Notes:
5147:    Currently, the default is to use a constant relative tolerance for
5148:    the inner linear solvers.  Alternatively, one can use the
5149:    Eisenstat-Walker method, where the relative convergence tolerance
5150:    is reset at each Newton iteration according progress of the nonlinear
5151:    solver.

5153:    Level: advanced

5155:    Reference:
5156:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5157:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

5159: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
5160: @*/
5161: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
5162: {
5166:   snes->ksp_ewconv = flag;
5167:   return(0);
5168: }

5170: /*@
5171:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
5172:    for computing relative tolerance for linear solvers within an
5173:    inexact Newton method.

5175:    Not Collective

5177:    Input Parameter:
5178: .  snes - SNES context

5180:    Output Parameter:
5181: .  flag - PETSC_TRUE or PETSC_FALSE

5183:    Notes:
5184:    Currently, the default is to use a constant relative tolerance for
5185:    the inner linear solvers.  Alternatively, one can use the
5186:    Eisenstat-Walker method, where the relative convergence tolerance
5187:    is reset at each Newton iteration according progress of the nonlinear
5188:    solver.

5190:    Level: advanced

5192:    Reference:
5193:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5194:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

5196: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
5197: @*/
5198: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
5199: {
5203:   *flag = snes->ksp_ewconv;
5204:   return(0);
5205: }

5207: /*@
5208:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5209:    convergence criteria for the linear solvers within an inexact
5210:    Newton method.

5212:    Logically Collective on SNES

5214:    Input Parameters:
5215: +    snes - SNES context
5216: .    version - version 1, 2 (default is 2) or 3
5217: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5218: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5219: .    gamma - multiplicative factor for version 2 rtol computation
5220:              (0 <= gamma2 <= 1)
5221: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
5222: .    alpha2 - power for safeguard
5223: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

5225:    Note:
5226:    Version 3 was contributed by Luis Chacon, June 2006.

5228:    Use PETSC_DEFAULT to retain the default for any of the parameters.

5230:    Level: advanced

5232:    Reference:
5233:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5234:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
5235:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

5237: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
5238: @*/
5239: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
5240: {
5241:   SNESKSPEW *kctx;

5245:   kctx = (SNESKSPEW*)snes->kspconvctx;
5246:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

5255:   if (version != PETSC_DEFAULT)   kctx->version   = version;
5256:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
5257:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
5258:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
5259:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
5260:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
5261:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

5263:   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);
5264:   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);
5265:   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);
5266:   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);
5267:   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);
5268:   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);
5269:   return(0);
5270: }

5272: /*@
5273:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5274:    convergence criteria for the linear solvers within an inexact
5275:    Newton method.

5277:    Not Collective

5279:    Input Parameters:
5280:      snes - SNES context

5282:    Output Parameters:
5283: +    version - version 1, 2 (default is 2) or 3
5284: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5285: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5286: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5287: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
5288: .    alpha2 - power for safeguard
5289: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

5291:    Level: advanced

5293: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
5294: @*/
5295: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
5296: {
5297:   SNESKSPEW *kctx;

5301:   kctx = (SNESKSPEW*)snes->kspconvctx;
5302:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
5303:   if (version)   *version   = kctx->version;
5304:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
5305:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
5306:   if (gamma)     *gamma     = kctx->gamma;
5307:   if (alpha)     *alpha     = kctx->alpha;
5308:   if (alpha2)    *alpha2    = kctx->alpha2;
5309:   if (threshold) *threshold = kctx->threshold;
5310:   return(0);
5311: }

5313:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5314: {
5316:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5317:   PetscReal      rtol  = PETSC_DEFAULT,stol;

5320:   if (!snes->ksp_ewconv) return(0);
5321:   if (!snes->iter) {
5322:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5323:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
5324:   }
5325:   else {
5326:     if (kctx->version == 1) {
5327:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
5328:       if (rtol < 0.0) rtol = -rtol;
5329:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
5330:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5331:     } else if (kctx->version == 2) {
5332:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5333:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
5334:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5335:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5336:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5337:       /* safeguard: avoid sharp decrease of rtol */
5338:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
5339:       stol = PetscMax(rtol,stol);
5340:       rtol = PetscMin(kctx->rtol_0,stol);
5341:       /* safeguard: avoid oversolving */
5342:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
5343:       stol = PetscMax(rtol,stol);
5344:       rtol = PetscMin(kctx->rtol_0,stol);
5345:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
5346:   }
5347:   /* safeguard: avoid rtol greater than one */
5348:   rtol = PetscMin(rtol,kctx->rtol_max);
5349:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
5350:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
5351:   return(0);
5352: }

5354: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5355: {
5357:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5358:   PCSide         pcside;
5359:   Vec            lres;

5362:   if (!snes->ksp_ewconv) return(0);
5363:   KSPGetTolerances(ksp,&kctx->rtol_last,NULL,NULL,NULL);
5364:   kctx->norm_last = snes->norm;
5365:   if (kctx->version == 1) {
5366:     PC        pc;
5367:     PetscBool isNone;

5369:     KSPGetPC(ksp, &pc);
5370:     PetscObjectTypeCompare((PetscObject) pc, PCNONE, &isNone);
5371:     KSPGetPCSide(ksp,&pcside);
5372:      if (pcside == PC_RIGHT || isNone) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
5373:       /* KSP residual is true linear residual */
5374:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
5375:     } else {
5376:       /* KSP residual is preconditioned residual */
5377:       /* compute true linear residual norm */
5378:       VecDuplicate(b,&lres);
5379:       MatMult(snes->jacobian,x,lres);
5380:       VecAYPX(lres,-1.0,b);
5381:       VecNorm(lres,NORM_2,&kctx->lresid_last);
5382:       VecDestroy(&lres);
5383:     }
5384:   }
5385:   return(0);
5386: }

5388: /*@
5389:    SNESGetKSP - Returns the KSP context for a SNES solver.

5391:    Not Collective, but if SNES object is parallel, then KSP object is parallel

5393:    Input Parameter:
5394: .  snes - the SNES context

5396:    Output Parameter:
5397: .  ksp - the KSP context

5399:    Notes:
5400:    The user can then directly manipulate the KSP context to set various
5401:    options, etc.  Likewise, the user can then extract and manipulate the
5402:    PC contexts as well.

5404:    Level: beginner

5406: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
5407: @*/
5408: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
5409: {


5416:   if (!snes->ksp) {
5417:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
5418:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
5419:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

5421:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
5422:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);

5424:     KSPMonitorSetFromOptions(snes->ksp, "-snes_monitor_ksp", "snes_preconditioned_residual", snes);
5425:     PetscObjectSetOptions((PetscObject)snes->ksp,((PetscObject)snes)->options);
5426:   }
5427:   *ksp = snes->ksp;
5428:   return(0);
5429: }


5432: #include <petsc/private/dmimpl.h>
5433: /*@
5434:    SNESSetDM - Sets the DM that may be used by some nonlinear solvers or their underlying preconditioners

5436:    Logically Collective on SNES

5438:    Input Parameters:
5439: +  snes - the nonlinear solver context
5440: -  dm - the dm, cannot be NULL

5442:    Notes:
5443:    A DM can only be used for solving one problem at a time because information about the problem is stored on the DM,
5444:    even when not using interfaces like DMSNESSetFunction().  Use DMClone() to get a distinct DM when solving different
5445:    problems using the same function space.

5447:    Level: intermediate

5449: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
5450: @*/
5451: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
5452: {
5454:   KSP            ksp;
5455:   DMSNES         sdm;

5460:   PetscObjectReference((PetscObject)dm);
5461:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
5462:     if (snes->dm->dmsnes && !dm->dmsnes) {
5463:       DMCopyDMSNES(snes->dm,dm);
5464:       DMGetDMSNES(snes->dm,&sdm);
5465:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5466:     }
5467:     DMCoarsenHookRemove(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
5468:     DMDestroy(&snes->dm);
5469:   }
5470:   snes->dm     = dm;
5471:   snes->dmAuto = PETSC_FALSE;

5473:   SNESGetKSP(snes,&ksp);
5474:   KSPSetDM(ksp,dm);
5475:   KSPSetDMActive(ksp,PETSC_FALSE);
5476:   if (snes->npc) {
5477:     SNESSetDM(snes->npc, snes->dm);
5478:     SNESSetNPCSide(snes,snes->npcside);
5479:   }
5480:   return(0);
5481: }

5483: /*@
5484:    SNESGetDM - Gets the DM that may be used by some preconditioners

5486:    Not Collective but DM obtained is parallel on SNES

5488:    Input Parameter:
5489: . snes - the preconditioner context

5491:    Output Parameter:
5492: .  dm - the dm

5494:    Level: intermediate

5496: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
5497: @*/
5498: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
5499: {

5504:   if (!snes->dm) {
5505:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
5506:     snes->dmAuto = PETSC_TRUE;
5507:   }
5508:   *dm = snes->dm;
5509:   return(0);
5510: }

5512: /*@
5513:   SNESSetNPC - Sets the nonlinear preconditioner to be used.

5515:   Collective on SNES

5517:   Input Parameters:
5518: + snes - iterative context obtained from SNESCreate()
5519: - pc   - the preconditioner object

5521:   Notes:
5522:   Use SNESGetNPC() to retrieve the preconditioner context (for example,
5523:   to configure it using the API).

5525:   Level: developer

5527: .seealso: SNESGetNPC(), SNESHasNPC()
5528: @*/
5529: PetscErrorCode SNESSetNPC(SNES snes, SNES pc)
5530: {

5537:   PetscObjectReference((PetscObject) pc);
5538:   SNESDestroy(&snes->npc);
5539:   snes->npc = pc;
5540:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->npc);
5541:   return(0);
5542: }

5544: /*@
5545:   SNESGetNPC - Creates a nonlinear preconditioning solver (SNES) to be used to precondition the nonlinear solver.

5547:   Not Collective; but any changes to the obtained SNES object must be applied collectively

5549:   Input Parameter:
5550: . snes - iterative context obtained from SNESCreate()

5552:   Output Parameter:
5553: . pc - preconditioner context

5555:   Options Database:
5556: . -npc_snes_type <type> - set the type of the SNES to use as the nonlinear preconditioner

5558:   Notes:
5559:     If a SNES was previously set with SNESSetNPC() then that SNES is returned, otherwise a new SNES object is created.

5561:     The (preconditioner) SNES returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5562:     SNES during SNESSetUp()

5564:   Level: developer

5566: .seealso: SNESSetNPC(), SNESHasNPC(), SNES, SNESCreate()
5567: @*/
5568: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5569: {
5571:   const char     *optionsprefix;

5576:   if (!snes->npc) {
5577:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->npc);
5578:     PetscObjectIncrementTabLevel((PetscObject)snes->npc,(PetscObject)snes,1);
5579:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->npc);
5580:     SNESGetOptionsPrefix(snes,&optionsprefix);
5581:     SNESSetOptionsPrefix(snes->npc,optionsprefix);
5582:     SNESAppendOptionsPrefix(snes->npc,"npc_");
5583:     SNESSetCountersReset(snes->npc,PETSC_FALSE);
5584:   }
5585:   *pc = snes->npc;
5586:   return(0);
5587: }

5589: /*@
5590:   SNESHasNPC - Returns whether a nonlinear preconditioner exists

5592:   Not Collective

5594:   Input Parameter:
5595: . snes - iterative context obtained from SNESCreate()

5597:   Output Parameter:
5598: . has_npc - whether the SNES has an NPC or not

5600:   Level: developer

5602: .seealso: SNESSetNPC(), SNESGetNPC()
5603: @*/
5604: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5605: {
5608:   *has_npc = (PetscBool) (snes->npc ? PETSC_TRUE : PETSC_FALSE);
5609:   return(0);
5610: }

5612: /*@
5613:     SNESSetNPCSide - Sets the preconditioning side.

5615:     Logically Collective on SNES

5617:     Input Parameter:
5618: .   snes - iterative context obtained from SNESCreate()

5620:     Output Parameter:
5621: .   side - the preconditioning side, where side is one of
5622: .vb
5623:       PC_LEFT - left preconditioning
5624:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5625: .ve

5627:     Options Database Keys:
5628: .   -snes_pc_side <right,left>

5630:     Notes:
5631:     SNESNRICHARDSON and SNESNCG only support left preconditioning.

5633:     Level: intermediate

5635: .seealso: SNESGetNPCSide(), KSPSetPCSide()
5636: @*/
5637: PetscErrorCode  SNESSetNPCSide(SNES snes,PCSide side)
5638: {
5642:   snes->npcside= side;
5643:   return(0);
5644: }

5646: /*@
5647:     SNESGetNPCSide - Gets the preconditioning side.

5649:     Not Collective

5651:     Input Parameter:
5652: .   snes - iterative context obtained from SNESCreate()

5654:     Output Parameter:
5655: .   side - the preconditioning side, where side is one of
5656: .vb
5657:       PC_LEFT - left preconditioning
5658:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5659: .ve

5661:     Level: intermediate

5663: .seealso: SNESSetNPCSide(), KSPGetPCSide()
5664: @*/
5665: PetscErrorCode  SNESGetNPCSide(SNES snes,PCSide *side)
5666: {
5670:   *side = snes->npcside;
5671:   return(0);
5672: }

5674: /*@
5675:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

5677:   Collective on SNES

5679:   Input Parameters:
5680: + snes - iterative context obtained from SNESCreate()
5681: - linesearch   - the linesearch object

5683:   Notes:
5684:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
5685:   to configure it using the API).

5687:   Level: developer

5689: .seealso: SNESGetLineSearch()
5690: @*/
5691: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5692: {

5699:   PetscObjectReference((PetscObject) linesearch);
5700:   SNESLineSearchDestroy(&snes->linesearch);

5702:   snes->linesearch = linesearch;

5704:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5705:   return(0);
5706: }

5708: /*@
5709:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
5710:   or creates a default line search instance associated with the SNES and returns it.

5712:   Not Collective

5714:   Input Parameter:
5715: . snes - iterative context obtained from SNESCreate()

5717:   Output Parameter:
5718: . linesearch - linesearch context

5720:   Level: beginner

5722: .seealso: SNESSetLineSearch(), SNESLineSearchCreate()
5723: @*/
5724: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5725: {
5727:   const char     *optionsprefix;

5732:   if (!snes->linesearch) {
5733:     SNESGetOptionsPrefix(snes, &optionsprefix);
5734:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
5735:     SNESLineSearchSetSNES(snes->linesearch, snes);
5736:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
5737:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
5738:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5739:   }
5740:   *linesearch = snes->linesearch;
5741:   return(0);
5742: }