Actual source code: snes.c

petsc-master 2019-09-20
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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: PETSC_EXTERN PetscErrorCode SNESComputeJacobian_DMDA(SNES,Vec,Mat,Mat,void*);

313: /*@C
314:    SNESView - Prints the SNES data structure.

316:    Collective on SNES

318:    Input Parameters:
319: +  SNES - the SNES context
320: -  viewer - visualization context

322:    Options Database Key:
323: .  -snes_view - Calls SNESView() at end of SNESSolve()

325:    Notes:
326:    The available visualization contexts include
327: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
328: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
329:          output where only the first processor opens
330:          the file.  All other processors send their
331:          data to the first processor to print.

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

336:    Level: beginner

338: .seealso: PetscViewerASCIIOpen()
339: @*/
340: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
341: {
342:   SNESKSPEW      *kctx;
344:   KSP            ksp;
345:   SNESLineSearch linesearch;
346:   PetscBool      iascii,isstring,isbinary,isdraw;
347:   DMSNES         dmsnes;
348: #if defined(PETSC_HAVE_SAWS)
349:   PetscBool      issaws;
350: #endif

354:   if (!viewer) {
355:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&viewer);
356:   }

360:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
361:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
362:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
363:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
364: #if defined(PETSC_HAVE_SAWS)
365:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
366: #endif
367:   if (iascii) {
368:     SNESNormSchedule normschedule;
369:     DM               dm;
370:     PetscErrorCode   (*cJ)(SNES,Vec,Mat,Mat,void*);
371:     void             *ctx;
372:     const char       *pre = "";

374:     PetscObjectPrintClassNamePrefixType((PetscObject)snes,viewer);
375:     if (!snes->setupcalled) {
376:       PetscViewerASCIIPrintf(viewer,"  SNES has not been set up so information may be incomplete\n");
377:     }
378:     if (snes->ops->view) {
379:       PetscViewerASCIIPushTab(viewer);
380:       (*snes->ops->view)(snes,viewer);
381:       PetscViewerASCIIPopTab(viewer);
382:     }
383:     PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
384:     PetscViewerASCIIPrintf(viewer,"  tolerances: relative=%g, absolute=%g, solution=%g\n",(double)snes->rtol,(double)snes->abstol,(double)snes->stol);
385:     if (snes->usesksp) {
386:       PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",snes->linear_its);
387:     }
388:     PetscViewerASCIIPrintf(viewer,"  total number of function evaluations=%D\n",snes->nfuncs);
389:     SNESGetNormSchedule(snes, &normschedule);
390:     if (normschedule > 0) {PetscViewerASCIIPrintf(viewer,"  norm schedule %s\n",SNESNormSchedules[normschedule]);}
391:     if (snes->gridsequence) {
392:       PetscViewerASCIIPrintf(viewer,"  total number of grid sequence refinements=%D\n",snes->gridsequence);
393:     }
394:     if (snes->ksp_ewconv) {
395:       kctx = (SNESKSPEW*)snes->kspconvctx;
396:       if (kctx) {
397:         PetscViewerASCIIPrintf(viewer,"  Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
398:         PetscViewerASCIIPrintf(viewer,"    rtol_0=%g, rtol_max=%g, threshold=%g\n",(double)kctx->rtol_0,(double)kctx->rtol_max,(double)kctx->threshold);
399:         PetscViewerASCIIPrintf(viewer,"    gamma=%g, alpha=%g, alpha2=%g\n",(double)kctx->gamma,(double)kctx->alpha,(double)kctx->alpha2);
400:       }
401:     }
402:     if (snes->lagpreconditioner == -1) {
403:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is never rebuilt\n");
404:     } else if (snes->lagpreconditioner > 1) {
405:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is rebuilt every %D new Jacobians\n",snes->lagpreconditioner);
406:     }
407:     if (snes->lagjacobian == -1) {
408:       PetscViewerASCIIPrintf(viewer,"  Jacobian is never rebuilt\n");
409:     } else if (snes->lagjacobian > 1) {
410:       PetscViewerASCIIPrintf(viewer,"  Jacobian is rebuilt every %D SNES iterations\n",snes->lagjacobian);
411:     }
412:     SNESGetDM(snes,&dm);
413:     DMSNESGetJacobian(dm,&cJ,&ctx);
414:     if (snes->mf_operator) {
415:       PetscViewerASCIIPrintf(viewer,"  Jacobian is applied matrix-free with differencing\n");
416:       pre  = "Preconditioning ";
417:     }
418:     if (cJ == SNESComputeJacobianDefault) {
419:       PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using finite differences one column at a time\n",pre);
420:     } else if (cJ == SNESComputeJacobianDefaultColor) {
421:       PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using finite differences with coloring\n",pre);
422:     /* it slightly breaks data encapsulation for access the DMDA information directly */
423:     } else if (cJ == SNESComputeJacobian_DMDA) {
424:       MatFDColoring fdcoloring;
425:       PetscObjectQuery((PetscObject)dm,"DMDASNES_FDCOLORING",(PetscObject*)&fdcoloring);
426:       if (fdcoloring) {
427:         PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using colored finite differences on a DMDA\n",pre);
428:       } else {
429:         PetscViewerASCIIPrintf(viewer,"  %sJacobian is built using a DMDA local Jacobian\n",pre);
430:       }
431:     } else if (snes->mf) {
432:       PetscViewerASCIIPrintf(viewer,"  Jacobian is applied matrix-free with differencing, no explict Jacobian\n");
433:     }
434:   } else if (isstring) {
435:     const char *type;
436:     SNESGetType(snes,&type);
437:     PetscViewerStringSPrintf(viewer," SNESType: %-7.7s",type);
438:     if (snes->ops->view) {(*snes->ops->view)(snes,viewer);}
439:   } else if (isbinary) {
440:     PetscInt    classid = SNES_FILE_CLASSID;
441:     MPI_Comm    comm;
442:     PetscMPIInt rank;
443:     char        type[256];

445:     PetscObjectGetComm((PetscObject)snes,&comm);
446:     MPI_Comm_rank(comm,&rank);
447:     if (!rank) {
448:       PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);
449:       PetscStrncpy(type,((PetscObject)snes)->type_name,sizeof(type));
450:       PetscViewerBinaryWrite(viewer,type,sizeof(type),PETSC_CHAR,PETSC_FALSE);
451:     }
452:     if (snes->ops->view) {
453:       (*snes->ops->view)(snes,viewer);
454:     }
455:   } else if (isdraw) {
456:     PetscDraw draw;
457:     char      str[36];
458:     PetscReal x,y,bottom,h;

460:     PetscViewerDrawGetDraw(viewer,0,&draw);
461:     PetscDrawGetCurrentPoint(draw,&x,&y);
462:     PetscStrncpy(str,"SNES: ",sizeof(str));
463:     PetscStrlcat(str,((PetscObject)snes)->type_name,sizeof(str));
464:     PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_BLUE,PETSC_DRAW_BLACK,str,NULL,&h);
465:     bottom = y - h;
466:     PetscDrawPushCurrentPoint(draw,x,bottom);
467:     if (snes->ops->view) {
468:       (*snes->ops->view)(snes,viewer);
469:     }
470: #if defined(PETSC_HAVE_SAWS)
471:   } else if (issaws) {
472:     PetscMPIInt rank;
473:     const char *name;

475:     PetscObjectGetName((PetscObject)snes,&name);
476:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
477:     if (!((PetscObject)snes)->amsmem && !rank) {
478:       char       dir[1024];

480:       PetscObjectViewSAWs((PetscObject)snes,viewer);
481:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
482:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
483:       if (!snes->conv_hist) {
484:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
485:       }
486:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
487:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
488:     }
489: #endif
490:   }
491:   if (snes->linesearch) {
492:     SNESGetLineSearch(snes, &linesearch);
493:     PetscViewerASCIIPushTab(viewer);
494:     SNESLineSearchView(linesearch, viewer);
495:     PetscViewerASCIIPopTab(viewer);
496:   }
497:   if (snes->npc && snes->usesnpc) {
498:     PetscViewerASCIIPushTab(viewer);
499:     SNESView(snes->npc, viewer);
500:     PetscViewerASCIIPopTab(viewer);
501:   }
502:   PetscViewerASCIIPushTab(viewer);
503:   DMGetDMSNES(snes->dm,&dmsnes);
504:   DMSNESView(dmsnes, viewer);
505:   PetscViewerASCIIPopTab(viewer);
506:   if (snes->usesksp) {
507:     SNESGetKSP(snes,&ksp);
508:     PetscViewerASCIIPushTab(viewer);
509:     KSPView(ksp,viewer);
510:     PetscViewerASCIIPopTab(viewer);
511:   }
512:   if (isdraw) {
513:     PetscDraw draw;
514:     PetscViewerDrawGetDraw(viewer,0,&draw);
515:     PetscDrawPopCurrentPoint(draw);
516:   }
517:   return(0);
518: }

520: /*
521:   We retain a list of functions that also take SNES command
522:   line options. These are called at the end SNESSetFromOptions()
523: */
524: #define MAXSETFROMOPTIONS 5
525: static PetscInt numberofsetfromoptions;
526: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

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

531:   Not Collective

533:   Input Parameter:
534: . snescheck - function that checks for options

536:   Level: developer

538: .seealso: SNESSetFromOptions()
539: @*/
540: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
541: {
543:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
544:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
545:   return(0);
546: }

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

550: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
551: {
552:   Mat            J;
554:   MatNullSpace   nullsp;


559:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
560:     Mat A = snes->jacobian, B = snes->jacobian_pre;
561:     MatCreateVecs(A ? A : B, NULL,&snes->vec_func);
562:   }

564:   if (version == 1) {
565:     MatCreateSNESMF(snes,&J);
566:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
567:     MatSetFromOptions(J);
568:   } else if (version == 2) {
569:     if (!snes->vec_func) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first");
570: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
571:     SNESDefaultMatrixFreeCreate2(snes,snes->vec_func,&J);
572: #else
573:     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP, "matrix-free operator rutines (version 2)");
574: #endif
575:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator rutines, only version 1 and 2");

577:   /* attach any user provided null space that was on Amat to the newly created matrix free matrix */
578:   if (snes->jacobian) {
579:     MatGetNullSpace(snes->jacobian,&nullsp);
580:     if (nullsp) {
581:       MatSetNullSpace(J,nullsp);
582:     }
583:   }

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

588:     /* This version replaces the user provided Jacobian matrix with a
589:        matrix-free version but still employs the user-provided preconditioner matrix. */
590:     SNESSetJacobian(snes,J,0,0,0);
591:   } else {
592:     /* This version replaces both the user-provided Jacobian and the user-
593:      provided preconditioner Jacobian with the default matrix free version. */
594:     if ((snes->npcside== PC_LEFT) && snes->npc) {
595:       if (!snes->jacobian){SNESSetJacobian(snes,J,0,0,0);}
596:     } else {
597:       KSP       ksp;
598:       PC        pc;
599:       PetscBool match;

601:       SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,0);
602:       /* Force no preconditioner */
603:       SNESGetKSP(snes,&ksp);
604:       KSPGetPC(ksp,&pc);
605:       PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&match);
606:       if (!match) {
607:         PetscInfo(snes,"Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n");
608:         PCSetType(pc,PCNONE);
609:       }
610:     }
611:   }
612:   MatDestroy(&J);
613:   return(0);
614: }

616: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
617: {
618:   SNES           snes = (SNES)ctx;
620:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

623:   if (PetscLogPrintInfo) {
624:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
625:     DMGetRefineLevel(dmfine,&finelevel);
626:     DMGetCoarsenLevel(dmfine,&fineclevel);
627:     DMGetRefineLevel(dmcoarse,&coarselevel);
628:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
629:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
630:   }
631:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
632:   else {
633:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
634:     Xfine = Xfine_named;
635:   }
636:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
637:   if (Inject) {
638:     MatRestrict(Inject,Xfine,Xcoarse);
639:   } else {
640:     MatRestrict(Restrict,Xfine,Xcoarse);
641:     VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
642:   }
643:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
644:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
645:   return(0);
646: }

648: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
649: {

653:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
654:   return(0);
655: }

657: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
658:  * safely call SNESGetDM() in their residual evaluation routine. */
659: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,void *ctx)
660: {
661:   SNES           snes = (SNES)ctx;
663:   Vec            X,Xnamed = NULL;
664:   DM             dmsave;
665:   void           *ctxsave;
666:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*) = NULL;

669:   dmsave = snes->dm;
670:   KSPGetDM(ksp,&snes->dm);
671:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
672:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
673:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
674:     X    = Xnamed;
675:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
676:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
677:     if (jac == SNESComputeJacobianDefaultColor) {
678:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,0);
679:     }
680:   }
681:   /* Make sure KSP DM has the Jacobian computation routine */
682:   {
683:     DMSNES sdm;

685:     DMGetDMSNES(snes->dm, &sdm);
686:     if (!sdm->ops->computejacobian) {
687:       DMCopyDMSNES(dmsave, snes->dm);
688:     }
689:   }
690:   /* Compute the operators */
691:   SNESComputeJacobian(snes,X,A,B);
692:   /* Put the previous context back */
693:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
694:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
695:   }

697:   if (Xnamed) {DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);}
698:   snes->dm = dmsave;
699:   return(0);
700: }

702: /*@
703:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

705:    Collective

707:    Input Arguments:
708: .  snes - snes to configure

710:    Level: developer

712: .seealso: SNESSetUp()
713: @*/
714: PetscErrorCode SNESSetUpMatrices(SNES snes)
715: {
717:   DM             dm;
718:   DMSNES         sdm;

721:   SNESGetDM(snes,&dm);
722:   DMGetDMSNES(dm,&sdm);
723:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_PLIB,"DMSNES not properly configured");
724:   else if (!snes->jacobian && snes->mf) {
725:     Mat  J;
726:     void *functx;
727:     MatCreateSNESMF(snes,&J);
728:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
729:     MatSetFromOptions(J);
730:     SNESGetFunction(snes,NULL,NULL,&functx);
731:     SNESSetJacobian(snes,J,J,0,0);
732:     MatDestroy(&J);
733:   } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
734:     Mat J,B;
735:     MatCreateSNESMF(snes,&J);
736:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
737:     MatSetFromOptions(J);
738:     DMCreateMatrix(snes->dm,&B);
739:     /* sdm->computejacobian was already set to reach here */
740:     SNESSetJacobian(snes,J,B,NULL,NULL);
741:     MatDestroy(&J);
742:     MatDestroy(&B);
743:   } else if (!snes->jacobian_pre) {
744:     PetscErrorCode (*nspconstr)(DM, PetscInt, MatNullSpace *);
745:     PetscDS          prob;
746:     Mat              J, B;
747:     MatNullSpace     nullspace = NULL;
748:     PetscBool        hasPrec   = PETSC_FALSE;
749:     PetscInt         Nf;

751:     J    = snes->jacobian;
752:     DMGetDS(dm, &prob);
753:     if (prob) {PetscDSHasJacobianPreconditioner(prob, &hasPrec);}
754:     if (J)            {PetscObjectReference((PetscObject) J);}
755:     else if (hasPrec) {DMCreateMatrix(snes->dm, &J);}
756:     DMCreateMatrix(snes->dm, &B);
757:     PetscDSGetNumFields(prob, &Nf);
758:     DMGetNullSpaceConstructor(snes->dm, Nf, &nspconstr);
759:     if (nspconstr) (*nspconstr)(snes->dm, -1, &nullspace);
760:     MatSetNullSpace(B, nullspace);
761:     MatNullSpaceDestroy(&nullspace);
762:     SNESSetJacobian(snes, J ? J : B, B, NULL, NULL);
763:     MatDestroy(&J);
764:     MatDestroy(&B);
765:   }
766:   {
767:     KSP ksp;
768:     SNESGetKSP(snes,&ksp);
769:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
770:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
771:   }
772:   return(0);
773: }

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

778:    Collective on SNES

780:    Input Parameters:
781: +  snes - SNES object you wish to monitor
782: .  name - the monitor type one is seeking
783: .  help - message indicating what monitoring is done
784: .  manual - manual page for the monitor
785: .  monitor - the monitor function
786: -  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

788:    Level: developer

790: .seealso: PetscOptionsGetViewer(), PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(),
791:           PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool()
792:           PetscOptionsInt(), PetscOptionsString(), PetscOptionsReal(), PetscOptionsBool(),
793:           PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(),
794:           PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(),
795:           PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(),
796:           PetscOptionsFList(), PetscOptionsEList()
797: @*/
798: PetscErrorCode  SNESMonitorSetFromOptions(SNES snes,const char name[],const char help[], const char manual[],PetscErrorCode (*monitor)(SNES,PetscInt,PetscReal,PetscViewerAndFormat*),PetscErrorCode (*monitorsetup)(SNES,PetscViewerAndFormat*))
799: {
800:   PetscErrorCode    ierr;
801:   PetscViewer       viewer;
802:   PetscViewerFormat format;
803:   PetscBool         flg;

806:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,name,&viewer,&format,&flg);
807:   if (flg) {
808:     PetscViewerAndFormat *vf;
809:     PetscViewerAndFormatCreate(viewer,format,&vf);
810:     PetscObjectDereference((PetscObject)viewer);
811:     if (monitorsetup) {
812:       (*monitorsetup)(snes,vf);
813:     }
814:     SNESMonitorSet(snes,(PetscErrorCode (*)(SNES,PetscInt,PetscReal,void*))monitor,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);
815:   }
816:   return(0);
817: }

819: /*@
820:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

822:    Collective on SNES

824:    Input Parameter:
825: .  snes - the SNES context

827:    Options Database Keys:
828: +  -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, SNESType for complete list
829: .  -snes_stol - convergence tolerance in terms of the norm
830:                 of the change in the solution between steps
831: .  -snes_atol <abstol> - absolute tolerance of residual norm
832: .  -snes_rtol <rtol> - relative decrease in tolerance norm from initial
833: .  -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
834: .  -snes_force_iteration <force> - force SNESSolve() to take at least one iteration
835: .  -snes_max_it <max_it> - maximum number of iterations
836: .  -snes_max_funcs <max_funcs> - maximum number of function evaluations
837: .  -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
838: .  -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
839: .  -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
840: .  -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
841: .  -snes_trtol <trtol> - trust region tolerance
842: .  -snes_no_convergence_test - skip convergence test in nonlinear
843:                                solver; hence iterations will continue until max_it
844:                                or some other criterion is reached. Saves expense
845:                                of convergence test
846: .  -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
847: .  -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
848: .  -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
849: .  -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
850: .  -snes_monitor_lg_residualnorm - plots residual norm at each iteration
851: .  -snes_monitor_lg_range - plots residual norm at each iteration
852: .  -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
853: .  -snes_fd_color - use finite differences with coloring to compute Jacobian
854: .  -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
855: .  -snes_converged_reason - print the reason for convergence/divergence after each solve
856: -  -npc_snes_type <type> - the SNES type to use as a nonlinear preconditioner

858:     Options Database for Eisenstat-Walker method:
859: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
860: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
861: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
862: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
863: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
864: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
865: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
866: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

868:    Notes:
869:    To see all options, run your program with the -help option or consult
870:    Users-Manual: ch_snes

872:    Level: beginner

874: .seealso: SNESSetOptionsPrefix(), SNESResetFromOptions()
875: @*/
876: PetscErrorCode  SNESSetFromOptions(SNES snes)
877: {
878:   PetscBool      flg,pcset,persist,set;
879:   PetscInt       i,indx,lag,grids;
880:   const char     *deft        = SNESNEWTONLS;
881:   const char     *convtests[] = {"default","skip"};
882:   SNESKSPEW      *kctx        = NULL;
883:   char           type[256], monfilename[PETSC_MAX_PATH_LEN];
885:   PCSide         pcside;
886:   const char     *optionsprefix;

890:   SNESRegisterAll();
891:   PetscObjectOptionsBegin((PetscObject)snes);
892:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
893:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
894:   if (flg) {
895:     SNESSetType(snes,type);
896:   } else if (!((PetscObject)snes)->type_name) {
897:     SNESSetType(snes,deft);
898:   }
899:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,NULL);
900:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,NULL);

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

912:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
913:   if (flg) {
914:     SNESSetLagPreconditioner(snes,lag);
915:   }
916:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
917:   if (flg) {
918:     SNESSetLagPreconditionerPersists(snes,persist);
919:   }
920:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
921:   if (flg) {
922:     SNESSetLagJacobian(snes,lag);
923:   }
924:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
925:   if (flg) {
926:     SNESSetLagJacobianPersists(snes,persist);
927:   }

929:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
930:   if (flg) {
931:     SNESSetGridSequence(snes,grids);
932:   }

934:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,2,"default",&indx,&flg);
935:   if (flg) {
936:     switch (indx) {
937:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
938:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL);    break;
939:     }
940:   }

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

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

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

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

952:   PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,NULL);
953:   PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,NULL);
954:   PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,NULL);
955:   PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,NULL);
956:   PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,NULL);
957:   PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,NULL);
958:   PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",kctx->threshold,&kctx->threshold,NULL);

960:   flg  = PETSC_FALSE;
961:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,&set);
962:   if (set && flg) {SNESMonitorCancel(snes);}

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

968:   SNESMonitorSetFromOptions(snes,"-snes_monitor_ratio","Monitor ratios of the norm of function for consecutive steps","SNESMonitorRatio",SNESMonitorRatio,SNESMonitorRatioSetUp);
969:   SNESMonitorSetFromOptions(snes,"-snes_monitor_field","Monitor norm of function (split into fields)","SNESMonitorDefaultField",SNESMonitorDefaultField,NULL);
970:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution","View solution at each iteration","SNESMonitorSolution",SNESMonitorSolution,NULL);
971:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution_update","View correction at each iteration","SNESMonitorSolutionUpdate",SNESMonitorSolutionUpdate,NULL);
972:   SNESMonitorSetFromOptions(snes,"-snes_monitor_residual","View residual at each iteration","SNESMonitorResidual",SNESMonitorResidual,NULL);
973:   SNESMonitorSetFromOptions(snes,"-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",SNESMonitorJacUpdateSpectrum,NULL);
974:   SNESMonitorSetFromOptions(snes,"-snes_monitor_fields","Monitor norm of function per field","SNESMonitorSet",SNESMonitorFields,NULL);

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

979:   flg  = PETSC_FALSE;
980:   PetscOptionsBool("-snes_monitor_lg_residualnorm","Plot function norm at each iteration","SNESMonitorLGResidualNorm",flg,&flg,NULL);
981:   if (flg) {
982:     PetscDrawLG ctx;

984:     SNESMonitorLGCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
985:     SNESMonitorSet(snes,SNESMonitorLGResidualNorm,ctx,(PetscErrorCode (*)(void**))PetscDrawLGDestroy);
986:   }
987:   flg  = PETSC_FALSE;
988:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
989:   if (flg) {
990:     PetscViewer ctx;

992:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
993:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
994:   }

996:   flg  = PETSC_FALSE;
997:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
998:   if (flg) {
999:     void    *functx;
1000:     DM      dm;
1001:     DMSNES  sdm;
1002:     SNESGetDM(snes,&dm);
1003:     DMGetDMSNES(dm,&sdm);
1004:     sdm->jacobianctx = NULL;
1005:     SNESGetFunction(snes,NULL,NULL,&functx);
1006:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
1007:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
1008:   }

1010:   flg  = PETSC_FALSE;
1011:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
1012:   if (flg) {
1013:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
1014:   }

1016:   flg  = PETSC_FALSE;
1017:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
1018:   if (flg) {
1019:     DM             dm;
1020:     DMSNES         sdm;
1021:     SNESGetDM(snes,&dm);
1022:     DMGetDMSNES(dm,&sdm);
1023:     sdm->jacobianctx = NULL;
1024:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,0);
1025:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
1026:   }

1028:   flg  = PETSC_FALSE;
1029:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf_operator,&flg);
1030:   if (flg && snes->mf_operator) {
1031:     snes->mf_operator = PETSC_TRUE;
1032:     snes->mf          = PETSC_TRUE;
1033:   }
1034:   flg  = PETSC_FALSE;
1035:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf,&flg);
1036:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1037:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,0);

1039:   flg  = PETSC_FALSE;
1040:   SNESGetNPCSide(snes,&pcside);
1041:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetNPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
1042:   if (flg) {SNESSetNPCSide(snes,pcside);}

1044: #if defined(PETSC_HAVE_SAWS)
1045:   /*
1046:     Publish convergence information using SAWs
1047:   */
1048:   flg  = PETSC_FALSE;
1049:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
1050:   if (flg) {
1051:     void *ctx;
1052:     SNESMonitorSAWsCreate(snes,&ctx);
1053:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
1054:   }
1055: #endif
1056: #if defined(PETSC_HAVE_SAWS)
1057:   {
1058:   PetscBool set;
1059:   flg  = PETSC_FALSE;
1060:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
1061:   if (set) {
1062:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
1063:   }
1064:   }
1065: #endif

1067:   for (i = 0; i < numberofsetfromoptions; i++) {
1068:     (*othersetfromoptions[i])(snes);
1069:   }

1071:   if (snes->ops->setfromoptions) {
1072:     (*snes->ops->setfromoptions)(PetscOptionsObject,snes);
1073:   }

1075:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
1076:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)snes);
1077:   PetscOptionsEnd();

1079:   if (snes->linesearch) {
1080:     SNESGetLineSearch(snes, &snes->linesearch);
1081:     SNESLineSearchSetFromOptions(snes->linesearch);
1082:   }

1084:   if (snes->usesksp) {
1085:     if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
1086:     KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
1087:     KSPSetFromOptions(snes->ksp);
1088:   }

1090:   /* if user has set the SNES NPC type via options database, create it. */
1091:   SNESGetOptionsPrefix(snes, &optionsprefix);
1092:   PetscOptionsHasName(((PetscObject)snes)->options,optionsprefix, "-npc_snes_type", &pcset);
1093:   if (pcset && (!snes->npc)) {
1094:     SNESGetNPC(snes, &snes->npc);
1095:   }
1096:   if (snes->npc) {
1097:     SNESSetFromOptions(snes->npc);
1098:   }
1099:   snes->setfromoptionscalled++;
1100:   return(0);
1101: }

1103: /*@
1104:    SNESResetFromOptions - Sets various SNES and KSP parameters from user options ONLY if the SNES was previously set from options

1106:    Collective on SNES

1108:    Input Parameter:
1109: .  snes - the SNES context

1111:    Level: beginner

1113: .seealso: SNESSetFromOptions(), SNESSetOptionsPrefix()
1114: @*/
1115: PetscErrorCode SNESResetFromOptions(SNES snes)
1116: {

1120:   if (snes->setfromoptionscalled) {SNESSetFromOptions(snes);}
1121:   return(0);
1122: }

1124: /*@C
1125:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1126:    the nonlinear solvers.

1128:    Logically Collective on SNES

1130:    Input Parameters:
1131: +  snes - the SNES context
1132: .  compute - function to compute the context
1133: -  destroy - function to destroy the context

1135:    Level: intermediate

1137:    Notes:
1138:    This function is currently not available from Fortran.

1140: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
1141: @*/
1142: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
1143: {
1146:   snes->ops->usercompute = compute;
1147:   snes->ops->userdestroy = destroy;
1148:   return(0);
1149: }

1151: /*@
1152:    SNESSetApplicationContext - Sets the optional user-defined context for
1153:    the nonlinear solvers.

1155:    Logically Collective on SNES

1157:    Input Parameters:
1158: +  snes - the SNES context
1159: -  usrP - optional user context

1161:    Level: intermediate

1163:    Fortran Notes:
1164:     To use this from Fortran you must write a Fortran interface definition for this
1165:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1167: .seealso: SNESGetApplicationContext()
1168: @*/
1169: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
1170: {
1172:   KSP            ksp;

1176:   SNESGetKSP(snes,&ksp);
1177:   KSPSetApplicationContext(ksp,usrP);
1178:   snes->user = usrP;
1179:   return(0);
1180: }

1182: /*@
1183:    SNESGetApplicationContext - Gets the user-defined context for the
1184:    nonlinear solvers.

1186:    Not Collective

1188:    Input Parameter:
1189: .  snes - SNES context

1191:    Output Parameter:
1192: .  usrP - user context

1194:    Fortran Notes:
1195:     To use this from Fortran you must write a Fortran interface definition for this
1196:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1198:    Level: intermediate

1200: .seealso: SNESSetApplicationContext()
1201: @*/
1202: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
1203: {
1206:   *(void**)usrP = snes->user;
1207:   return(0);
1208: }

1210: /*@
1211:    SNESSetUseMatrixFree - indicates that SNES should use matrix free finite difference matrix vector products internally to apply
1212:                           the Jacobian.

1214:    Collective on SNES

1216:    Input Parameters:
1217: +  snes - SNES context
1218: .  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored
1219: -  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used

1221:    Options Database:
1222: + -snes_mf - use matrix free for both the mat and pmat operator
1223: - -snes_mf_operator - use matrix free only for the mat operator

1225:    Level: intermediate

1227: .seealso:   SNESGetUseMatrixFree(), MatCreateSNESMF()
1228: @*/
1229: PetscErrorCode  SNESSetUseMatrixFree(SNES snes,PetscBool mf_operator,PetscBool mf)
1230: {
1235:   if (mf && !mf_operator) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"If using mf must also use mf_operator");
1236:   snes->mf          = mf;
1237:   snes->mf_operator = mf_operator;
1238:   return(0);
1239: }

1241: /*@
1242:    SNESGetUseMatrixFree - indicates if the SNES uses matrix free finite difference matrix vector products to apply
1243:                           the Jacobian.

1245:    Collective on SNES

1247:    Input Parameter:
1248: .  snes - SNES context

1250:    Output Parameters:
1251: +  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored
1252: -  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used

1254:    Options Database:
1255: + -snes_mf - use matrix free for both the mat and pmat operator
1256: - -snes_mf_operator - use matrix free only for the mat operator

1258:    Level: intermediate

1260: .seealso:   SNESSetUseMatrixFree(), MatCreateSNESMF()
1261: @*/
1262: PetscErrorCode  SNESGetUseMatrixFree(SNES snes,PetscBool *mf_operator,PetscBool *mf)
1263: {
1266:   if (mf)          *mf          = snes->mf;
1267:   if (mf_operator) *mf_operator = snes->mf_operator;
1268:   return(0);
1269: }

1271: /*@
1272:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1273:    at this time.

1275:    Not Collective

1277:    Input Parameter:
1278: .  snes - SNES context

1280:    Output Parameter:
1281: .  iter - iteration number

1283:    Notes:
1284:    For example, during the computation of iteration 2 this would return 1.

1286:    This is useful for using lagged Jacobians (where one does not recompute the
1287:    Jacobian at each SNES iteration). For example, the code
1288: .vb
1289:       SNESGetIterationNumber(snes,&it);
1290:       if (!(it % 2)) {
1291:         [compute Jacobian here]
1292:       }
1293: .ve
1294:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1295:    recomputed every second SNES iteration.

1297:    After the SNES solve is complete this will return the number of nonlinear iterations used.

1299:    Level: intermediate

1301: .seealso:   SNESGetLinearSolveIterations()
1302: @*/
1303: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1304: {
1308:   *iter = snes->iter;
1309:   return(0);
1310: }

1312: /*@
1313:    SNESSetIterationNumber - Sets the current iteration number.

1315:    Not Collective

1317:    Input Parameter:
1318: +  snes - SNES context
1319: -  iter - iteration number

1321:    Level: developer

1323: .seealso:   SNESGetLinearSolveIterations()
1324: @*/
1325: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1326: {

1331:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1332:   snes->iter = iter;
1333:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1334:   return(0);
1335: }

1337: /*@
1338:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1339:    attempted by the nonlinear solver.

1341:    Not Collective

1343:    Input Parameter:
1344: .  snes - SNES context

1346:    Output Parameter:
1347: .  nfails - number of unsuccessful steps attempted

1349:    Notes:
1350:    This counter is reset to zero for each successive call to SNESSolve().

1352:    Level: intermediate

1354: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1355:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1356: @*/
1357: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1358: {
1362:   *nfails = snes->numFailures;
1363:   return(0);
1364: }

1366: /*@
1367:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1368:    attempted by the nonlinear solver before it gives up.

1370:    Not Collective

1372:    Input Parameters:
1373: +  snes     - SNES context
1374: -  maxFails - maximum of unsuccessful steps

1376:    Level: intermediate

1378: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1379:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1380: @*/
1381: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1382: {
1385:   snes->maxFailures = maxFails;
1386:   return(0);
1387: }

1389: /*@
1390:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1391:    attempted by the nonlinear solver before it gives up.

1393:    Not Collective

1395:    Input Parameter:
1396: .  snes     - SNES context

1398:    Output Parameter:
1399: .  maxFails - maximum of unsuccessful steps

1401:    Level: intermediate

1403: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1404:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1406: @*/
1407: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1408: {
1412:   *maxFails = snes->maxFailures;
1413:   return(0);
1414: }

1416: /*@
1417:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1418:      done by SNES.

1420:    Not Collective

1422:    Input Parameter:
1423: .  snes     - SNES context

1425:    Output Parameter:
1426: .  nfuncs - number of evaluations

1428:    Level: intermediate

1430:    Notes:
1431:     Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1433: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1434: @*/
1435: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1436: {
1440:   *nfuncs = snes->nfuncs;
1441:   return(0);
1442: }

1444: /*@
1445:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1446:    linear solvers.

1448:    Not Collective

1450:    Input Parameter:
1451: .  snes - SNES context

1453:    Output Parameter:
1454: .  nfails - number of failed solves

1456:    Level: intermediate

1458:    Options Database Keys:
1459: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1461:    Notes:
1462:    This counter is reset to zero for each successive call to SNESSolve().

1464: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1465: @*/
1466: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1467: {
1471:   *nfails = snes->numLinearSolveFailures;
1472:   return(0);
1473: }

1475: /*@
1476:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1477:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1479:    Logically Collective on SNES

1481:    Input Parameters:
1482: +  snes     - SNES context
1483: -  maxFails - maximum allowed linear solve failures

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

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

1504: /*@
1505:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1506:      are allowed before SNES terminates

1508:    Not Collective

1510:    Input Parameter:
1511: .  snes     - SNES context

1513:    Output Parameter:
1514: .  maxFails - maximum of unsuccessful solves allowed

1516:    Level: intermediate

1518:    Notes:
1519:     By default this is 1; that is SNES returns on the first failed linear solve

1521: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1522: @*/
1523: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1524: {
1528:   *maxFails = snes->maxLinearSolveFailures;
1529:   return(0);
1530: }

1532: /*@
1533:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1534:    used by the nonlinear solver.

1536:    Not Collective

1538:    Input Parameter:
1539: .  snes - SNES context

1541:    Output Parameter:
1542: .  lits - number of linear iterations

1544:    Notes:
1545:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1547:    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
1548:    then call KSPGetIterationNumber() after the failed solve.

1550:    Level: intermediate

1552: .seealso:  SNESGetIterationNumber(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1553: @*/
1554: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1555: {
1559:   *lits = snes->linear_its;
1560:   return(0);
1561: }

1563: /*@
1564:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1565:    are reset every time SNESSolve() is called.

1567:    Logically Collective on SNES

1569:    Input Parameter:
1570: +  snes - SNES context
1571: -  reset - whether to reset the counters or not

1573:    Notes:
1574:    This defaults to PETSC_TRUE

1576:    Level: developer

1578: .seealso:  SNESGetNumberFunctionEvals(), SNESGetLinearSolveIterations(), SNESGetNPC()
1579: @*/
1580: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1581: {
1585:   snes->counters_reset = reset;
1586:   return(0);
1587: }


1590: /*@
1591:    SNESSetKSP - Sets a KSP context for the SNES object to use

1593:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1595:    Input Parameters:
1596: +  snes - the SNES context
1597: -  ksp - the KSP context

1599:    Notes:
1600:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1601:    so this routine is rarely needed.

1603:    The KSP object that is already in the SNES object has its reference count
1604:    decreased by one.

1606:    Level: developer

1608: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1609: @*/
1610: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1611: {

1618:   PetscObjectReference((PetscObject)ksp);
1619:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1620:   snes->ksp = ksp;
1621:   return(0);
1622: }

1624: /* -----------------------------------------------------------*/
1625: /*@
1626:    SNESCreate - Creates a nonlinear solver context.

1628:    Collective

1630:    Input Parameters:
1631: .  comm - MPI communicator

1633:    Output Parameter:
1634: .  outsnes - the new SNES context

1636:    Options Database Keys:
1637: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1638:                and no preconditioning matrix
1639: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1640:                products, and a user-provided preconditioning matrix
1641:                as set by SNESSetJacobian()
1642: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1644:    Level: beginner

1646:    Developer Notes:
1647:     SNES always creates a KSP object even though many SNES methods do not use it. This is
1648:                     unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1649:                     particular method does use KSP and regulates if the information about the KSP is printed
1650:                     in SNESView(). TSSetFromOptions() does call SNESSetFromOptions() which can lead to users being confused
1651:                     by help messages about meaningless SNES options.

1653:                     SNES always creates the snes->kspconvctx even though it is used by only one type. This should
1654:                     be fixed.

1656: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner()

1658: @*/
1659: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1660: {
1662:   SNES           snes;
1663:   SNESKSPEW      *kctx;

1667:   *outsnes = NULL;
1668:   SNESInitializePackage();

1670:   PetscHeaderCreate(snes,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1672:   snes->ops->converged    = SNESConvergedDefault;
1673:   snes->usesksp           = PETSC_TRUE;
1674:   snes->tolerancesset     = PETSC_FALSE;
1675:   snes->max_its           = 50;
1676:   snes->max_funcs         = 10000;
1677:   snes->norm              = 0.0;
1678:   snes->xnorm             = 0.0;
1679:   snes->ynorm             = 0.0;
1680:   snes->normschedule      = SNES_NORM_ALWAYS;
1681:   snes->functype          = SNES_FUNCTION_DEFAULT;
1682: #if defined(PETSC_USE_REAL_SINGLE)
1683:   snes->rtol              = 1.e-5;
1684: #else
1685:   snes->rtol              = 1.e-8;
1686: #endif
1687:   snes->ttol              = 0.0;
1688: #if defined(PETSC_USE_REAL_SINGLE)
1689:   snes->abstol            = 1.e-25;
1690: #else
1691:   snes->abstol            = 1.e-50;
1692: #endif
1693: #if defined(PETSC_USE_REAL_SINGLE)
1694:   snes->stol              = 1.e-5;
1695: #else
1696:   snes->stol              = 1.e-8;
1697: #endif
1698: #if defined(PETSC_USE_REAL_SINGLE)
1699:   snes->deltatol          = 1.e-6;
1700: #else
1701:   snes->deltatol          = 1.e-12;
1702: #endif
1703:   snes->divtol            = 1.e4;
1704:   snes->rnorm0            = 0;
1705:   snes->nfuncs            = 0;
1706:   snes->numFailures       = 0;
1707:   snes->maxFailures       = 1;
1708:   snes->linear_its        = 0;
1709:   snes->lagjacobian       = 1;
1710:   snes->jac_iter          = 0;
1711:   snes->lagjac_persist    = PETSC_FALSE;
1712:   snes->lagpreconditioner = 1;
1713:   snes->pre_iter          = 0;
1714:   snes->lagpre_persist    = PETSC_FALSE;
1715:   snes->numbermonitors    = 0;
1716:   snes->data              = 0;
1717:   snes->setupcalled       = PETSC_FALSE;
1718:   snes->ksp_ewconv        = PETSC_FALSE;
1719:   snes->nwork             = 0;
1720:   snes->work              = 0;
1721:   snes->nvwork            = 0;
1722:   snes->vwork             = 0;
1723:   snes->conv_hist_len     = 0;
1724:   snes->conv_hist_max     = 0;
1725:   snes->conv_hist         = NULL;
1726:   snes->conv_hist_its     = NULL;
1727:   snes->conv_hist_reset   = PETSC_TRUE;
1728:   snes->counters_reset    = PETSC_TRUE;
1729:   snes->vec_func_init_set = PETSC_FALSE;
1730:   snes->reason            = SNES_CONVERGED_ITERATING;
1731:   snes->npcside           = PC_RIGHT;
1732:   snes->setfromoptionscalled = 0;

1734:   snes->mf          = PETSC_FALSE;
1735:   snes->mf_operator = PETSC_FALSE;
1736:   snes->mf_version  = 1;

1738:   snes->numLinearSolveFailures = 0;
1739:   snes->maxLinearSolveFailures = 1;

1741:   snes->vizerotolerance = 1.e-8;
1742: #if defined(PETSC_USE_DEBUG)
1743:   snes->checkjacdomainerror = PETSC_TRUE;
1744: #else
1745:   snes->checkjacdomainerror = PETSC_FALSE;
1746: #endif

1748:   /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1749:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

1751:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1752:   PetscNewLog(snes,&kctx);

1754:   snes->kspconvctx  = (void*)kctx;
1755:   kctx->version     = 2;
1756:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1757:                              this was too large for some test cases */
1758:   kctx->rtol_last   = 0.0;
1759:   kctx->rtol_max    = .9;
1760:   kctx->gamma       = 1.0;
1761:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1762:   kctx->alpha2      = kctx->alpha;
1763:   kctx->threshold   = .1;
1764:   kctx->lresid_last = 0.0;
1765:   kctx->norm_last   = 0.0;

1767:   *outsnes = snes;
1768:   return(0);
1769: }

1771: /*MC
1772:     SNESFunction - Functional form used to convey the nonlinear function to be solved by SNES

1774:      Synopsis:
1775:      #include "petscsnes.h"
1776:      PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1778:      Input Parameters:
1779: +     snes - the SNES context
1780: .     x    - state at which to evaluate residual
1781: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1783:      Output Parameter:
1784: .     f  - vector to put residual (function value)

1786:    Level: intermediate

1788: .seealso:   SNESSetFunction(), SNESGetFunction()
1789: M*/

1791: /*@C
1792:    SNESSetFunction - Sets the function evaluation routine and function
1793:    vector for use by the SNES routines in solving systems of nonlinear
1794:    equations.

1796:    Logically Collective on SNES

1798:    Input Parameters:
1799: +  snes - the SNES context
1800: .  r - vector to store function value
1801: .  f - function evaluation routine; see SNESFunction for calling sequence details
1802: -  ctx - [optional] user-defined context for private data for the
1803:          function evaluation routine (may be NULL)

1805:    Notes:
1806:    The Newton-like methods typically solve linear systems of the form
1807: $      f'(x) x = -f(x),
1808:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1810:    Level: beginner

1812: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1813: @*/
1814: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1815: {
1817:   DM             dm;

1821:   if (r) {
1824:     PetscObjectReference((PetscObject)r);
1825:     VecDestroy(&snes->vec_func);

1827:     snes->vec_func = r;
1828:   }
1829:   SNESGetDM(snes,&dm);
1830:   DMSNESSetFunction(dm,f,ctx);
1831:   return(0);
1832: }


1835: /*@C
1836:    SNESSetInitialFunction - Sets the function vector to be used as the
1837:    function norm at the initialization of the method.  In some
1838:    instances, the user has precomputed the function before calling
1839:    SNESSolve.  This function allows one to avoid a redundant call
1840:    to SNESComputeFunction in that case.

1842:    Logically Collective on SNES

1844:    Input Parameters:
1845: +  snes - the SNES context
1846: -  f - vector to store function value

1848:    Notes:
1849:    This should not be modified during the solution procedure.

1851:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1853:    Level: developer

1855: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1856: @*/
1857: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1858: {
1860:   Vec            vec_func;

1866:   if (snes->npcside== PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1867:     snes->vec_func_init_set = PETSC_FALSE;
1868:     return(0);
1869:   }
1870:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1871:   VecCopy(f, vec_func);

1873:   snes->vec_func_init_set = PETSC_TRUE;
1874:   return(0);
1875: }

1877: /*@
1878:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1879:    of the SNES method.

1881:    Logically Collective on SNES

1883:    Input Parameters:
1884: +  snes - the SNES context
1885: -  normschedule - the frequency of norm computation

1887:    Options Database Key:
1888: .  -snes_norm_schedule <none, always, initialonly, finalonly, initalfinalonly>

1890:    Notes:
1891:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1892:    of the nonlinear function and the taking of its norm at every iteration to
1893:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1894:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1895:    may either be monitored for convergence or not.  As these are often used as nonlinear
1896:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1897:    their solution.

1899:    Level: developer

1901: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1902: @*/
1903: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1904: {
1907:   snes->normschedule = normschedule;
1908:   return(0);
1909: }


1912: /*@
1913:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1914:    of the SNES method.

1916:    Logically Collective on SNES

1918:    Input Parameters:
1919: +  snes - the SNES context
1920: -  normschedule - the type of the norm used

1922:    Level: advanced

1924: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1925: @*/
1926: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1927: {
1930:   *normschedule = snes->normschedule;
1931:   return(0);
1932: }


1935: /*@
1936:   SNESSetFunctionNorm - Sets the last computed residual norm.

1938:   Logically Collective on SNES

1940:   Input Parameters:
1941: + snes - the SNES context

1943: - normschedule - the frequency of norm computation

1945:   Level: developer

1947: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1948: @*/
1949: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
1950: {
1953:   snes->norm = norm;
1954:   return(0);
1955: }

1957: /*@
1958:   SNESGetFunctionNorm - Gets the last computed norm of the residual

1960:   Not Collective

1962:   Input Parameter:
1963: . snes - the SNES context

1965:   Output Parameter:
1966: . norm - the last computed residual norm

1968:   Level: developer

1970: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1971: @*/
1972: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
1973: {
1977:   *norm = snes->norm;
1978:   return(0);
1979: }

1981: /*@
1982:   SNESGetUpdateNorm - Gets the last computed norm of the Newton update

1984:   Not Collective

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

1989:   Output Parameter:
1990: . ynorm - the last computed update norm

1992:   Level: developer

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

2005: /*@
2006:   SNESGetSolutionNorm - Gets the last computed norm of the solution

2008:   Not Collective

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

2013:   Output Parameter:
2014: . xnorm - the last computed solution norm

2016:   Level: developer

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

2029: /*@C
2030:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
2031:    of the SNES method.

2033:    Logically Collective on SNES

2035:    Input Parameters:
2036: +  snes - the SNES context
2037: -  normschedule - the frequency of norm computation

2039:    Notes:
2040:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
2041:    of the nonlinear function and the taking of its norm at every iteration to
2042:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
2043:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
2044:    may either be monitored for convergence or not.  As these are often used as nonlinear
2045:    preconditioners, monitoring the norm of their error is not a useful enterprise within
2046:    their solution.

2048:    Level: developer

2050: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2051: @*/
2052: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
2053: {
2056:   snes->functype = type;
2057:   return(0);
2058: }


2061: /*@C
2062:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
2063:    of the SNES method.

2065:    Logically Collective on SNES

2067:    Input Parameters:
2068: +  snes - the SNES context
2069: -  normschedule - the type of the norm used

2071:    Level: advanced

2073: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2074: @*/
2075: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2076: {
2079:   *type = snes->functype;
2080:   return(0);
2081: }

2083: /*MC
2084:     SNESNGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

2086:      Synopsis:
2087:      #include <petscsnes.h>
2088: $    SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);

2090: +  X   - solution vector
2091: .  B   - RHS vector
2092: -  ctx - optional user-defined Gauss-Seidel context

2094:    Level: intermediate

2096: .seealso:   SNESSetNGS(), SNESGetNGS()
2097: M*/

2099: /*@C
2100:    SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2101:    use with composed nonlinear solvers.

2103:    Input Parameters:
2104: +  snes   - the SNES context
2105: .  f - function evaluation routine to apply Gauss-Seidel see SNESNGSFunction
2106: -  ctx    - [optional] user-defined context for private data for the
2107:             smoother evaluation routine (may be NULL)

2109:    Notes:
2110:    The NGS routines are used by the composed nonlinear solver to generate
2111:     a problem appropriate update to the solution, particularly FAS.

2113:    Level: intermediate

2115: .seealso: SNESGetFunction(), SNESComputeNGS()
2116: @*/
2117: PetscErrorCode SNESSetNGS(SNES snes,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
2118: {
2120:   DM             dm;

2124:   SNESGetDM(snes,&dm);
2125:   DMSNESSetNGS(dm,f,ctx);
2126:   return(0);
2127: }

2129: PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
2130: {
2132:   DM             dm;
2133:   DMSNES         sdm;

2136:   SNESGetDM(snes,&dm);
2137:   DMGetDMSNES(dm,&sdm);
2138:   if (!sdm->ops->computepfunction) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");
2139:   if (!sdm->ops->computepjacobian) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard Jacobian.");
2140:   /*  A(x)*x - b(x) */
2141:   PetscStackPush("SNES Picard user function");
2142:   (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
2143:   PetscStackPop;
2144:   PetscStackPush("SNES Picard user Jacobian");
2145:   (*sdm->ops->computepjacobian)(snes,x,snes->jacobian,snes->jacobian_pre,sdm->pctx);
2146:   PetscStackPop;
2147:   VecScale(f,-1.0);
2148:   MatMultAdd(snes->jacobian,x,f,f);
2149:   return(0);
2150: }

2152: PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat J,Mat B,void *ctx)
2153: {
2155:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2156:   return(0);
2157: }

2159: /*@C
2160:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

2162:    Logically Collective on SNES

2164:    Input Parameters:
2165: +  snes - the SNES context
2166: .  r - vector to store function value
2167: .  b - function evaluation routine
2168: .  Amat - matrix with which A(x) x - b(x) is to be computed
2169: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
2170: .  J  - function to compute matrix value, see SNESJacobianFunction for details on its calling sequence
2171: -  ctx - [optional] user-defined context for private data for the
2172:          function evaluation routine (may be NULL)

2174:    Notes:
2175:     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
2176:     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.

2178:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

2180: $     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}
2181: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

2183:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

2185:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2186:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

2188:    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
2189:    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
2190:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

2192:    Level: intermediate

2194: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard(), SNESJacobianFunction
2195: @*/
2196: 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)
2197: {
2199:   DM             dm;

2203:   SNESGetDM(snes, &dm);
2204:   DMSNESSetPicard(dm,b,J,ctx);
2205:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
2206:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
2207:   return(0);
2208: }

2210: /*@C
2211:    SNESGetPicard - Returns the context for the Picard iteration

2213:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

2215:    Input Parameter:
2216: .  snes - the SNES context

2218:    Output Parameter:
2219: +  r - the function (or NULL)
2220: .  f - the function (or NULL); see SNESFunction for calling sequence details
2221: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
2222: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
2223: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
2224: -  ctx - the function context (or NULL)

2226:    Level: advanced

2228: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
2229: @*/
2230: 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)
2231: {
2233:   DM             dm;

2237:   SNESGetFunction(snes,r,NULL,NULL);
2238:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
2239:   SNESGetDM(snes,&dm);
2240:   DMSNESGetPicard(dm,f,J,ctx);
2241:   return(0);
2242: }

2244: /*@C
2245:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

2247:    Logically Collective on SNES

2249:    Input Parameters:
2250: +  snes - the SNES context
2251: .  func - function evaluation routine
2252: -  ctx - [optional] user-defined context for private data for the
2253:          function evaluation routine (may be NULL)

2255:    Calling sequence of func:
2256: $    func (SNES snes,Vec x,void *ctx);

2258: .  f - function vector
2259: -  ctx - optional user-defined function context

2261:    Level: intermediate

2263: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
2264: @*/
2265: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
2266: {
2269:   if (func) snes->ops->computeinitialguess = func;
2270:   if (ctx)  snes->initialguessP            = ctx;
2271:   return(0);
2272: }

2274: /* --------------------------------------------------------------- */
2275: /*@C
2276:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
2277:    it assumes a zero right hand side.

2279:    Logically Collective on SNES

2281:    Input Parameter:
2282: .  snes - the SNES context

2284:    Output Parameter:
2285: .  rhs - the right hand side vector or NULL if the right hand side vector is null

2287:    Level: intermediate

2289: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2290: @*/
2291: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2292: {
2296:   *rhs = snes->vec_rhs;
2297:   return(0);
2298: }

2300: /*@
2301:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2303:    Collective on SNES

2305:    Input Parameters:
2306: +  snes - the SNES context
2307: -  x - input vector

2309:    Output Parameter:
2310: .  y - function vector, as set by SNESSetFunction()

2312:    Notes:
2313:    SNESComputeFunction() is typically used within nonlinear solvers
2314:    implementations, so most users would not generally call this routine
2315:    themselves.

2317:    Level: developer

2319: .seealso: SNESSetFunction(), SNESGetFunction()
2320: @*/
2321: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2322: {
2324:   DM             dm;
2325:   DMSNES         sdm;

2333:   VecValidValues(x,2,PETSC_TRUE);

2335:   SNESGetDM(snes,&dm);
2336:   DMGetDMSNES(dm,&sdm);
2337:   if (sdm->ops->computefunction) {
2338:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2339:       PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2340:     }
2341:     VecLockReadPush(x);
2342:     PetscStackPush("SNES user function");
2343:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2344:     PetscStackPop;
2345:     VecLockReadPop(x);
2346:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2347:       PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2348:     }
2349:   } else if (snes->vec_rhs) {
2350:     MatMult(snes->jacobian, x, y);
2351:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2352:   if (snes->vec_rhs) {
2353:     VecAXPY(y,-1.0,snes->vec_rhs);
2354:   }
2355:   snes->nfuncs++;
2356:   /*
2357:      domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2358:      propagate the value to all processes
2359:   */
2360:   if (snes->domainerror) {
2361:     VecSetInf(y);
2362:   }
2363:   return(0);
2364: }

2366: /*@
2367:    SNESComputeNGS - Calls the Gauss-Seidel function that has been set with  SNESSetNGS().

2369:    Collective on SNES

2371:    Input Parameters:
2372: +  snes - the SNES context
2373: .  x - input vector
2374: -  b - rhs vector

2376:    Output Parameter:
2377: .  x - new solution vector

2379:    Notes:
2380:    SNESComputeNGS() is typically used within composed nonlinear solver
2381:    implementations, so most users would not generally call this routine
2382:    themselves.

2384:    Level: developer

2386: .seealso: SNESSetNGS(), SNESComputeFunction()
2387: @*/
2388: PetscErrorCode  SNESComputeNGS(SNES snes,Vec b,Vec x)
2389: {
2391:   DM             dm;
2392:   DMSNES         sdm;

2400:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2401:   PetscLogEventBegin(SNES_NGSEval,snes,x,b,0);
2402:   SNESGetDM(snes,&dm);
2403:   DMGetDMSNES(dm,&sdm);
2404:   if (sdm->ops->computegs) {
2405:     if (b) {VecLockReadPush(b);}
2406:     PetscStackPush("SNES user NGS");
2407:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2408:     PetscStackPop;
2409:     if (b) {VecLockReadPop(b);}
2410:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2411:   PetscLogEventEnd(SNES_NGSEval,snes,x,b,0);
2412:   return(0);
2413: }

2415: PetscErrorCode SNESTestJacobian(SNES snes)
2416: {
2417:   Mat               A,B,C,D,jacobian;
2418:   Vec               x = snes->vec_sol,f = snes->vec_func;
2419:   PetscErrorCode    ierr;
2420:   PetscReal         nrm,gnorm;
2421:   PetscReal         threshold = 1.e-5;
2422:   MatType           mattype;
2423:   PetscInt          m,n,M,N;
2424:   void              *functx;
2425:   PetscBool         complete_print = PETSC_FALSE,threshold_print = PETSC_FALSE,test = PETSC_FALSE,flg;
2426:   PetscViewer       viewer,mviewer;
2427:   MPI_Comm          comm;
2428:   PetscInt          tabs;
2429:   static PetscBool  directionsprinted = PETSC_FALSE;
2430:   PetscViewerFormat format;

2433:   PetscObjectOptionsBegin((PetscObject)snes);
2434:   PetscOptionsName("-snes_test_jacobian","Compare hand-coded and finite difference Jacobians","None",&test);
2435:   PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold,NULL);
2436:   PetscOptionsViewer("-snes_test_jacobian_view","View difference between hand-coded and finite difference Jacobians element entries","None",&mviewer,&format,&complete_print);
2437:   if (!complete_print) {
2438:     PetscOptionsViewer("-snes_test_jacobian_display","Display difference between hand-coded and finite difference Jacobians","None",&mviewer,&format,&complete_print);
2439:   }
2440:   /* for compatibility with PETSc 3.9 and older. */
2441:   PetscOptionsReal("-snes_test_jacobian_display_threshold", "Display difference between hand-coded and finite difference Jacobians which exceed input threshold", "None", threshold, &threshold, &threshold_print);
2442:   PetscOptionsEnd();
2443:   if (!test) return(0);

2445:   PetscObjectGetComm((PetscObject)snes,&comm);
2446:   PetscViewerASCIIGetStdout(comm,&viewer);
2447:   PetscViewerASCIIGetTab(viewer, &tabs);
2448:   PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel);
2449:   PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian -------------\n");
2450:   if (!complete_print && !directionsprinted) {
2451:     PetscViewerASCIIPrintf(viewer,"  Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n");
2452:     PetscViewerASCIIPrintf(viewer,"    of hand-coded and finite difference Jacobian entries greater than <threshold>.\n");
2453:   }
2454:   if (!directionsprinted) {
2455:     PetscViewerASCIIPrintf(viewer,"  Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n");
2456:     PetscViewerASCIIPrintf(viewer,"    O(1.e-8), the hand-coded Jacobian is probably correct.\n");
2457:     directionsprinted = PETSC_TRUE;
2458:   }
2459:   if (complete_print) {
2460:     PetscViewerPushFormat(mviewer,format);
2461:   }

2463:   PetscObjectTypeCompare((PetscObject)snes->jacobian,MATMFFD,&flg);
2464:   if (!flg) jacobian = snes->jacobian;
2465:   else jacobian = snes->jacobian_pre;

2467:   if (!x) {
2468:     MatCreateVecs(jacobian, &x, NULL);
2469:   } else {
2470:     PetscObjectReference((PetscObject) x);
2471:   }
2472:   if (!f) {
2473:     VecDuplicate(x, &f);
2474:   } else {
2475:     PetscObjectReference((PetscObject) f);
2476:   }
2477:   /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2478:   SNESComputeFunction(snes,x,f);
2479:   VecDestroy(&f);

2481:   while (jacobian) {
2482:     PetscObjectBaseTypeCompareAny((PetscObject)jacobian,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPISBAIJ,"");
2483:     if (flg) {
2484:       A    = jacobian;
2485:       PetscObjectReference((PetscObject)A);
2486:     } else {
2487:       MatComputeOperator(jacobian,MATAIJ,&A);
2488:     }

2490:     MatGetType(A,&mattype);
2491:     MatGetSize(A,&M,&N);
2492:     MatGetLocalSize(A,&m,&n);

2494:     MatCreate(PetscObjectComm((PetscObject)A),&B);
2495:     MatSetType(B,mattype);
2496:     MatSetSizes(B,m,n,M,N);
2497:     MatSetBlockSizesFromMats(B,A,A);
2498:     MatSetUp(B);
2499:     MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2501:     SNESGetFunction(snes,NULL,NULL,&functx);
2502:     SNESComputeJacobianDefault(snes,x,B,B,functx);

2504:     MatDuplicate(B,MAT_COPY_VALUES,&D);
2505:     MatAYPX(D,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2506:     MatNorm(D,NORM_FROBENIUS,&nrm);
2507:     MatNorm(A,NORM_FROBENIUS,&gnorm);
2508:     MatDestroy(&D);
2509:     if (!gnorm) gnorm = 1; /* just in case */
2510:     PetscViewerASCIIPrintf(viewer,"  ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n",(double)(nrm/gnorm),(double)nrm);

2512:     if (complete_print) {
2513:       PetscViewerASCIIPrintf(viewer,"  Hand-coded Jacobian ----------\n");
2514:       MatView(jacobian,mviewer);
2515:       PetscViewerASCIIPrintf(viewer,"  Finite difference Jacobian ----------\n");
2516:       MatView(B,mviewer);
2517:     }

2519:     if (threshold_print || complete_print) {
2520:       PetscInt          Istart, Iend, *ccols, bncols, cncols, j, row;
2521:       PetscScalar       *cvals;
2522:       const PetscInt    *bcols;
2523:       const PetscScalar *bvals;

2525:       MatCreate(PetscObjectComm((PetscObject)A),&C);
2526:       MatSetType(C,mattype);
2527:       MatSetSizes(C,m,n,M,N);
2528:       MatSetBlockSizesFromMats(C,A,A);
2529:       MatSetUp(C);
2530:       MatSetOption(C,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2532:       MatAYPX(B,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2533:       MatGetOwnershipRange(B,&Istart,&Iend);

2535:       for (row = Istart; row < Iend; row++) {
2536:         MatGetRow(B,row,&bncols,&bcols,&bvals);
2537:         PetscMalloc2(bncols,&ccols,bncols,&cvals);
2538:         for (j = 0, cncols = 0; j < bncols; j++) {
2539:           if (PetscAbsScalar(bvals[j]) > threshold) {
2540:             ccols[cncols] = bcols[j];
2541:             cvals[cncols] = bvals[j];
2542:             cncols += 1;
2543:           }
2544:         }
2545:         if (cncols) {
2546:           MatSetValues(C,1,&row,cncols,ccols,cvals,INSERT_VALUES);
2547:         }
2548:         MatRestoreRow(B,row,&bncols,&bcols,&bvals);
2549:         PetscFree2(ccols,cvals);
2550:       }
2551:       MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
2552:       MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
2553:       PetscViewerASCIIPrintf(viewer,"  Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n",(double)threshold);
2554:       MatView(C,complete_print ? mviewer : viewer);
2555:       MatDestroy(&C);
2556:     }
2557:     MatDestroy(&A);
2558:     MatDestroy(&B);

2560:     if (jacobian != snes->jacobian_pre) {
2561:       jacobian = snes->jacobian_pre;
2562:       PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian for preconditioner -------------\n");
2563:     }
2564:     else jacobian = NULL;
2565:   }
2566:   VecDestroy(&x);
2567:   if (complete_print) {
2568:     PetscViewerPopFormat(mviewer);
2569:   }
2570:   if (mviewer) { PetscViewerDestroy(&mviewer); }
2571:   PetscViewerASCIISetTab(viewer,tabs);
2572:   return(0);
2573: }

2575: /*@
2576:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2578:    Collective on SNES

2580:    Input Parameters:
2581: +  snes - the SNES context
2582: -  x - input vector

2584:    Output Parameters:
2585: +  A - Jacobian matrix
2586: -  B - optional preconditioning matrix

2588:   Options Database Keys:
2589: +    -snes_lag_preconditioner <lag>
2590: .    -snes_lag_jacobian <lag>
2591: .    -snes_test_jacobian - compare the user provided Jacobian with one compute via finite differences to check for errors
2592: .    -snes_test_jacobian_display - 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
2593: .    -snes_test_jacobian_display_threshold <numerical value>  - display entries in the difference between the user provided Jacobian and finite difference Jacobian that are greater than a certain value to help users detect errors
2594: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2595: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2596: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2597: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2598: .    -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2599: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2600: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2601: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2602: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2603: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2604: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2607:    Notes:
2608:    Most users should not need to explicitly call this routine, as it
2609:    is used internally within the nonlinear solvers.

2611:    Developer Notes:
2612:     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
2613:       for with the SNESType of test that has been removed.

2615:    Level: developer

2617: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2618: @*/
2619: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat A,Mat B)
2620: {
2622:   PetscBool      flag;
2623:   DM             dm;
2624:   DMSNES         sdm;
2625:   KSP            ksp;

2631:   VecValidValues(X,2,PETSC_TRUE);
2632:   SNESGetDM(snes,&dm);
2633:   DMGetDMSNES(dm,&sdm);

2635:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2637:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2639:   if (snes->lagjacobian == -2) {
2640:     snes->lagjacobian = -1;

2642:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2643:   } else if (snes->lagjacobian == -1) {
2644:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2645:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2646:     if (flag) {
2647:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2648:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2649:     }
2650:     return(0);
2651:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2652:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2653:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2654:     if (flag) {
2655:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2656:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2657:     }
2658:     return(0);
2659:   }
2660:   if (snes->npc && snes->npcside== PC_LEFT) {
2661:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2662:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2663:       return(0);
2664:   }

2666:   PetscLogEventBegin(SNES_JacobianEval,snes,X,A,B);
2667:   VecLockReadPush(X);
2668:   PetscStackPush("SNES user Jacobian function");
2669:   (*sdm->ops->computejacobian)(snes,X,A,B,sdm->jacobianctx);
2670:   PetscStackPop;
2671:   VecLockReadPop(X);
2672:   PetscLogEventEnd(SNES_JacobianEval,snes,X,A,B);

2674:   /* the next line ensures that snes->ksp exists */
2675:   SNESGetKSP(snes,&ksp);
2676:   if (snes->lagpreconditioner == -2) {
2677:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");
2678:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2679:     snes->lagpreconditioner = -1;
2680:   } else if (snes->lagpreconditioner == -1) {
2681:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2682:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2683:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2684:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2685:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2686:   } else {
2687:     PetscInfo(snes,"Rebuilding preconditioner\n");
2688:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2689:   }

2691:   SNESTestJacobian(snes);
2692:   /* make sure user returned a correct Jacobian and preconditioner */
2695:   {
2696:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2697:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit",NULL,NULL,&flag);
2698:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",NULL,NULL,&flag_draw);
2699:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",NULL,NULL,&flag_contour);
2700:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_operator",NULL,NULL,&flag_operator);
2701:     if (flag || flag_draw || flag_contour) {
2702:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2703:       PetscViewer  vdraw,vstdout;
2704:       PetscBool    flg;
2705:       if (flag_operator) {
2706:         MatComputeOperator(A,MATAIJ,&Bexp_mine);
2707:         Bexp = Bexp_mine;
2708:       } else {
2709:         /* See if the preconditioning matrix can be viewed and added directly */
2710:         PetscObjectBaseTypeCompareAny((PetscObject)B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2711:         if (flg) Bexp = B;
2712:         else {
2713:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2714:           MatComputeOperator(B,MATAIJ,&Bexp_mine);
2715:           Bexp = Bexp_mine;
2716:         }
2717:       }
2718:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2719:       SNESComputeJacobianDefault(snes,X,FDexp,FDexp,NULL);
2720:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2721:       if (flag_draw || flag_contour) {
2722:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2723:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2724:       } else vdraw = NULL;
2725:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2726:       if (flag) {MatView(Bexp,vstdout);}
2727:       if (vdraw) {MatView(Bexp,vdraw);}
2728:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2729:       if (flag) {MatView(FDexp,vstdout);}
2730:       if (vdraw) {MatView(FDexp,vdraw);}
2731:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2732:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2733:       if (flag) {MatView(FDexp,vstdout);}
2734:       if (vdraw) {              /* Always use contour for the difference */
2735:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2736:         MatView(FDexp,vdraw);
2737:         PetscViewerPopFormat(vdraw);
2738:       }
2739:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2740:       PetscViewerDestroy(&vdraw);
2741:       MatDestroy(&Bexp_mine);
2742:       MatDestroy(&FDexp);
2743:     }
2744:   }
2745:   {
2746:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2747:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2748:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring",NULL,NULL,&flag);
2749:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_display",NULL,NULL,&flag_display);
2750:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",NULL,NULL,&flag_draw);
2751:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",NULL,NULL,&flag_contour);
2752:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",NULL,NULL,&flag_threshold);
2753:     if (flag_threshold) {
2754:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2755:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2756:     }
2757:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2758:       Mat            Bfd;
2759:       PetscViewer    vdraw,vstdout;
2760:       MatColoring    coloring;
2761:       ISColoring     iscoloring;
2762:       MatFDColoring  matfdcoloring;
2763:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2764:       void           *funcctx;
2765:       PetscReal      norm1,norm2,normmax;

2767:       MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2768:       MatColoringCreate(Bfd,&coloring);
2769:       MatColoringSetType(coloring,MATCOLORINGSL);
2770:       MatColoringSetFromOptions(coloring);
2771:       MatColoringApply(coloring,&iscoloring);
2772:       MatColoringDestroy(&coloring);
2773:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2774:       MatFDColoringSetFromOptions(matfdcoloring);
2775:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2776:       ISColoringDestroy(&iscoloring);

2778:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2779:       SNESGetFunction(snes,NULL,&func,&funcctx);
2780:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2781:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2782:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2783:       MatFDColoringSetFromOptions(matfdcoloring);
2784:       MatFDColoringApply(Bfd,matfdcoloring,X,snes);
2785:       MatFDColoringDestroy(&matfdcoloring);

2787:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2788:       if (flag_draw || flag_contour) {
2789:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2790:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2791:       } else vdraw = NULL;
2792:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2793:       if (flag_display) {MatView(B,vstdout);}
2794:       if (vdraw) {MatView(B,vdraw);}
2795:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2796:       if (flag_display) {MatView(Bfd,vstdout);}
2797:       if (vdraw) {MatView(Bfd,vdraw);}
2798:       MatAYPX(Bfd,-1.0,B,SAME_NONZERO_PATTERN);
2799:       MatNorm(Bfd,NORM_1,&norm1);
2800:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2801:       MatNorm(Bfd,NORM_MAX,&normmax);
2802:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2803:       if (flag_display) {MatView(Bfd,vstdout);}
2804:       if (vdraw) {              /* Always use contour for the difference */
2805:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2806:         MatView(Bfd,vdraw);
2807:         PetscViewerPopFormat(vdraw);
2808:       }
2809:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2811:       if (flag_threshold) {
2812:         PetscInt bs,rstart,rend,i;
2813:         MatGetBlockSize(B,&bs);
2814:         MatGetOwnershipRange(B,&rstart,&rend);
2815:         for (i=rstart; i<rend; i++) {
2816:           const PetscScalar *ba,*ca;
2817:           const PetscInt    *bj,*cj;
2818:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2819:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2820:           MatGetRow(B,i,&bn,&bj,&ba);
2821:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2822:           if (bn != cn) SETERRQ(((PetscObject)A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2823:           for (j=0; j<bn; j++) {
2824:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2825:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2826:               maxentrycol = bj[j];
2827:               maxentry    = PetscRealPart(ba[j]);
2828:             }
2829:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2830:               maxdiffcol = bj[j];
2831:               maxdiff    = PetscRealPart(ca[j]);
2832:             }
2833:             if (rdiff > maxrdiff) {
2834:               maxrdiffcol = bj[j];
2835:               maxrdiff    = rdiff;
2836:             }
2837:           }
2838:           if (maxrdiff > 1) {
2839:             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);
2840:             for (j=0; j<bn; j++) {
2841:               PetscReal rdiff;
2842:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2843:               if (rdiff > 1) {
2844:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2845:               }
2846:             }
2847:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2848:           }
2849:           MatRestoreRow(B,i,&bn,&bj,&ba);
2850:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2851:         }
2852:       }
2853:       PetscViewerDestroy(&vdraw);
2854:       MatDestroy(&Bfd);
2855:     }
2856:   }
2857:   return(0);
2858: }

2860: /*MC
2861:     SNESJacobianFunction - Function used to convey the nonlinear Jacobian of the function to be solved by SNES

2863:      Synopsis:
2864:      #include "petscsnes.h"
2865:      PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);

2867: +  x - input vector
2868: .  Amat - the matrix that defines the (approximate) Jacobian
2869: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2870: -  ctx - [optional] user-defined Jacobian context

2872:    Level: intermediate

2874: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2875: M*/

2877: /*@C
2878:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2879:    location to store the matrix.

2881:    Logically Collective on SNES

2883:    Input Parameters:
2884: +  snes - the SNES context
2885: .  Amat - the matrix that defines the (approximate) Jacobian
2886: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2887: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value), see SNESJacobianFunction for details
2888: -  ctx - [optional] user-defined context for private data for the
2889:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2891:    Notes:
2892:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2893:    each matrix.

2895:    If you know the operator Amat has a null space you can use MatSetNullSpace() and MatSetTransposeNullSpace() to supply the null
2896:    space to Amat and the KSP solvers will automatically use that null space as needed during the solution process.

2898:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2899:    must be a MatFDColoring.

2901:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2902:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2904:    Level: beginner

2906: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J,
2907:           SNESSetPicard(), SNESJacobianFunction
2908: @*/
2909: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2910: {
2912:   DM             dm;

2920:   SNESGetDM(snes,&dm);
2921:   DMSNESSetJacobian(dm,J,ctx);
2922:   if (Amat) {
2923:     PetscObjectReference((PetscObject)Amat);
2924:     MatDestroy(&snes->jacobian);

2926:     snes->jacobian = Amat;
2927:   }
2928:   if (Pmat) {
2929:     PetscObjectReference((PetscObject)Pmat);
2930:     MatDestroy(&snes->jacobian_pre);

2932:     snes->jacobian_pre = Pmat;
2933:   }
2934:   return(0);
2935: }

2937: /*@C
2938:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2939:    provided context for evaluating the Jacobian.

2941:    Not Collective, but Mat object will be parallel if SNES object is

2943:    Input Parameter:
2944: .  snes - the nonlinear solver context

2946:    Output Parameters:
2947: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
2948: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
2949: .  J - location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
2950: -  ctx - location to stash Jacobian ctx (or NULL)

2952:    Level: advanced

2954: .seealso: SNESSetJacobian(), SNESComputeJacobian(), SNESJacobianFunction, SNESGetFunction()
2955: @*/
2956: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
2957: {
2959:   DM             dm;
2960:   DMSNES         sdm;

2964:   if (Amat) *Amat = snes->jacobian;
2965:   if (Pmat) *Pmat = snes->jacobian_pre;
2966:   SNESGetDM(snes,&dm);
2967:   DMGetDMSNES(dm,&sdm);
2968:   if (J) *J = sdm->ops->computejacobian;
2969:   if (ctx) *ctx = sdm->jacobianctx;
2970:   return(0);
2971: }

2973: /*@
2974:    SNESSetUp - Sets up the internal data structures for the later use
2975:    of a nonlinear solver.

2977:    Collective on SNES

2979:    Input Parameters:
2980: .  snes - the SNES context

2982:    Notes:
2983:    For basic use of the SNES solvers the user need not explicitly call
2984:    SNESSetUp(), since these actions will automatically occur during
2985:    the call to SNESSolve().  However, if one wishes to control this
2986:    phase separately, SNESSetUp() should be called after SNESCreate()
2987:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

2989:    Level: advanced

2991: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
2992: @*/
2993: PetscErrorCode  SNESSetUp(SNES snes)
2994: {
2996:   DM             dm;
2997:   DMSNES         sdm;
2998:   SNESLineSearch linesearch, pclinesearch;
2999:   void           *lsprectx,*lspostctx;
3000:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
3001:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
3002:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
3003:   Vec            f,fpc;
3004:   void           *funcctx;
3005:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
3006:   void           *jacctx,*appctx;
3007:   Mat            j,jpre;

3011:   if (snes->setupcalled) return(0);
3012:   PetscLogEventBegin(SNES_Setup,snes,0,0,0);

3014:   if (!((PetscObject)snes)->type_name) {
3015:     SNESSetType(snes,SNESNEWTONLS);
3016:   }

3018:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

3020:   SNESGetDM(snes,&dm);
3021:   DMGetDMSNES(dm,&sdm);
3022:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
3023:   if (!sdm->ops->computejacobian) {
3024:     DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
3025:   }
3026:   if (!snes->vec_func) {
3027:     DMCreateGlobalVector(dm,&snes->vec_func);
3028:   }

3030:   if (!snes->ksp) {
3031:     SNESGetKSP(snes, &snes->ksp);
3032:   }

3034:   if (snes->linesearch) {
3035:     SNESGetLineSearch(snes, &snes->linesearch);
3036:     SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);
3037:   }

3039:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3040:     snes->mf          = PETSC_TRUE;
3041:     snes->mf_operator = PETSC_FALSE;
3042:   }

3044:   if (snes->npc) {
3045:     /* copy the DM over */
3046:     SNESGetDM(snes,&dm);
3047:     SNESSetDM(snes->npc,dm);

3049:     SNESGetFunction(snes,&f,&func,&funcctx);
3050:     VecDuplicate(f,&fpc);
3051:     SNESSetFunction(snes->npc,fpc,func,funcctx);
3052:     SNESGetJacobian(snes,&j,&jpre,&jac,&jacctx);
3053:     SNESSetJacobian(snes->npc,j,jpre,jac,jacctx);
3054:     SNESGetApplicationContext(snes,&appctx);
3055:     SNESSetApplicationContext(snes->npc,appctx);
3056:     VecDestroy(&fpc);

3058:     /* copy the function pointers over */
3059:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->npc);

3061:     /* default to 1 iteration */
3062:     SNESSetTolerances(snes->npc,0.0,0.0,0.0,1,snes->npc->max_funcs);
3063:     if (snes->npcside==PC_RIGHT) {
3064:       SNESSetNormSchedule(snes->npc,SNES_NORM_FINAL_ONLY);
3065:     } else {
3066:       SNESSetNormSchedule(snes->npc,SNES_NORM_NONE);
3067:     }
3068:     SNESSetFromOptions(snes->npc);

3070:     /* copy the line search context over */
3071:     if (snes->linesearch && snes->npc->linesearch) {
3072:       SNESGetLineSearch(snes,&linesearch);
3073:       SNESGetLineSearch(snes->npc,&pclinesearch);
3074:       SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
3075:       SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
3076:       SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
3077:       SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
3078:       PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
3079:     }
3080:   }
3081:   if (snes->mf) {
3082:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
3083:   }
3084:   if (snes->ops->usercompute && !snes->user) {
3085:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
3086:   }

3088:   snes->jac_iter = 0;
3089:   snes->pre_iter = 0;

3091:   if (snes->ops->setup) {
3092:     (*snes->ops->setup)(snes);
3093:   }

3095:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3096:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3097:       if (snes->linesearch){
3098:         SNESGetLineSearch(snes,&linesearch);
3099:         SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultNPC);
3100:       }
3101:     }
3102:   }
3103:   PetscLogEventEnd(SNES_Setup,snes,0,0,0);
3104:   snes->setupcalled = PETSC_TRUE;
3105:   return(0);
3106: }

3108: /*@
3109:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

3111:    Collective on SNES

3113:    Input Parameter:
3114: .  snes - iterative context obtained from SNESCreate()

3116:    Level: intermediate

3118:    Notes:
3119:     Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

3121: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
3122: @*/
3123: PetscErrorCode  SNESReset(SNES snes)
3124: {

3129:   if (snes->ops->userdestroy && snes->user) {
3130:     (*snes->ops->userdestroy)((void**)&snes->user);
3131:     snes->user = NULL;
3132:   }
3133:   if (snes->npc) {
3134:     SNESReset(snes->npc);
3135:   }

3137:   if (snes->ops->reset) {
3138:     (*snes->ops->reset)(snes);
3139:   }
3140:   if (snes->ksp) {
3141:     KSPReset(snes->ksp);
3142:   }

3144:   if (snes->linesearch) {
3145:     SNESLineSearchReset(snes->linesearch);
3146:   }

3148:   VecDestroy(&snes->vec_rhs);
3149:   VecDestroy(&snes->vec_sol);
3150:   VecDestroy(&snes->vec_sol_update);
3151:   VecDestroy(&snes->vec_func);
3152:   MatDestroy(&snes->jacobian);
3153:   MatDestroy(&snes->jacobian_pre);
3154:   VecDestroyVecs(snes->nwork,&snes->work);
3155:   VecDestroyVecs(snes->nvwork,&snes->vwork);

3157:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

3159:   snes->nwork       = snes->nvwork = 0;
3160:   snes->setupcalled = PETSC_FALSE;
3161:   return(0);
3162: }

3164: /*@
3165:    SNESDestroy - Destroys the nonlinear solver context that was created
3166:    with SNESCreate().

3168:    Collective on SNES

3170:    Input Parameter:
3171: .  snes - the SNES context

3173:    Level: beginner

3175: .seealso: SNESCreate(), SNESSolve()
3176: @*/
3177: PetscErrorCode  SNESDestroy(SNES *snes)
3178: {

3182:   if (!*snes) return(0);
3184:   if (--((PetscObject)(*snes))->refct > 0) {*snes = 0; return(0);}

3186:   SNESReset((*snes));
3187:   SNESDestroy(&(*snes)->npc);

3189:   /* if memory was published with SAWs then destroy it */
3190:   PetscObjectSAWsViewOff((PetscObject)*snes);
3191:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

3193:   if ((*snes)->dm) {DMCoarsenHookRemove((*snes)->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,*snes);}
3194:   DMDestroy(&(*snes)->dm);
3195:   KSPDestroy(&(*snes)->ksp);
3196:   SNESLineSearchDestroy(&(*snes)->linesearch);

3198:   PetscFree((*snes)->kspconvctx);
3199:   if ((*snes)->ops->convergeddestroy) {
3200:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
3201:   }
3202:   if ((*snes)->conv_hist_alloc) {
3203:     PetscFree2((*snes)->conv_hist,(*snes)->conv_hist_its);
3204:   }
3205:   SNESMonitorCancel((*snes));
3206:   PetscHeaderDestroy(snes);
3207:   return(0);
3208: }

3210: /* ----------- Routines to set solver parameters ---------- */

3212: /*@
3213:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

3215:    Logically Collective on SNES

3217:    Input Parameters:
3218: +  snes - the SNES context
3219: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3220:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3222:    Options Database Keys:
3223: .    -snes_lag_preconditioner <lag>

3225:    Notes:
3226:    The default is 1
3227:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3228:    If  -1 is used before the very first nonlinear solve the preconditioner is still built because there is no previous preconditioner to use

3230:    Level: intermediate

3232: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian()

3234: @*/
3235: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
3236: {
3239:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3240:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3242:   snes->lagpreconditioner = lag;
3243:   return(0);
3244: }

3246: /*@
3247:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

3249:    Logically Collective on SNES

3251:    Input Parameters:
3252: +  snes - the SNES context
3253: -  steps - the number of refinements to do, defaults to 0

3255:    Options Database Keys:
3256: .    -snes_grid_sequence <steps>

3258:    Level: intermediate

3260:    Notes:
3261:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3263: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetGridSequence()

3265: @*/
3266: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
3267: {
3271:   snes->gridsequence = steps;
3272:   return(0);
3273: }

3275: /*@
3276:    SNESGetGridSequence - gets the number of steps of grid sequencing that SNES does

3278:    Logically Collective on SNES

3280:    Input Parameter:
3281: .  snes - the SNES context

3283:    Output Parameter:
3284: .  steps - the number of refinements to do, defaults to 0

3286:    Options Database Keys:
3287: .    -snes_grid_sequence <steps>

3289:    Level: intermediate

3291:    Notes:
3292:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3294: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetGridSequence()

3296: @*/
3297: PetscErrorCode  SNESGetGridSequence(SNES snes,PetscInt *steps)
3298: {
3301:   *steps = snes->gridsequence;
3302:   return(0);
3303: }

3305: /*@
3306:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

3308:    Not Collective

3310:    Input Parameter:
3311: .  snes - the SNES context

3313:    Output Parameter:
3314: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3315:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3317:    Options Database Keys:
3318: .    -snes_lag_preconditioner <lag>

3320:    Notes:
3321:    The default is 1
3322:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3324:    Level: intermediate

3326: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner()

3328: @*/
3329: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
3330: {
3333:   *lag = snes->lagpreconditioner;
3334:   return(0);
3335: }

3337: /*@
3338:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
3339:      often the preconditioner is rebuilt.

3341:    Logically Collective on SNES

3343:    Input Parameters:
3344: +  snes - the SNES context
3345: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3346:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

3348:    Options Database Keys:
3349: .    -snes_lag_jacobian <lag>

3351:    Notes:
3352:    The default is 1
3353:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3354:    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
3355:    at the next Newton step but never again (unless it is reset to another value)

3357:    Level: intermediate

3359: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobian()

3361: @*/
3362: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
3363: {
3366:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3367:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3369:   snes->lagjacobian = lag;
3370:   return(0);
3371: }

3373: /*@
3374:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

3376:    Not Collective

3378:    Input Parameter:
3379: .  snes - the SNES context

3381:    Output Parameter:
3382: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3383:          the Jacobian is built etc.

3385:    Options Database Keys:
3386: .    -snes_lag_jacobian <lag>

3388:    Notes:
3389:    The default is 1
3390:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3392:    Level: intermediate

3394: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner()

3396: @*/
3397: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
3398: {
3401:   *lag = snes->lagjacobian;
3402:   return(0);
3403: }

3405: /*@
3406:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

3408:    Logically collective on SNES

3410:    Input Parameter:
3411: +  snes - the SNES context
3412: -   flg - jacobian lagging persists if true

3414:    Options Database Keys:
3415: .    -snes_lag_jacobian_persists <flg>

3417:    Notes:
3418:     This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3419:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3420:    timesteps may present huge efficiency gains.

3422:    Level: developer

3424: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3426: @*/
3427: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3428: {
3432:   snes->lagjac_persist = flg;
3433:   return(0);
3434: }

3436: /*@
3437:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple solves

3439:    Logically Collective on SNES

3441:    Input Parameter:
3442: +  snes - the SNES context
3443: -   flg - preconditioner lagging persists if true

3445:    Options Database Keys:
3446: .    -snes_lag_jacobian_persists <flg>

3448:    Notes:
3449:     This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3450:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3451:    several timesteps may present huge efficiency gains.

3453:    Level: developer

3455: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3457: @*/
3458: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3459: {
3463:   snes->lagpre_persist = flg;
3464:   return(0);
3465: }

3467: /*@
3468:    SNESSetForceIteration - force SNESSolve() to take at least one iteration regardless of the initial residual norm

3470:    Logically Collective on SNES

3472:    Input Parameters:
3473: +  snes - the SNES context
3474: -  force - PETSC_TRUE require at least one iteration

3476:    Options Database Keys:
3477: .    -snes_force_iteration <force> - Sets forcing an iteration

3479:    Notes:
3480:    This is used sometimes with TS to prevent TS from detecting a false steady state solution

3482:    Level: intermediate

3484: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3485: @*/
3486: PetscErrorCode  SNESSetForceIteration(SNES snes,PetscBool force)
3487: {
3490:   snes->forceiteration = force;
3491:   return(0);
3492: }

3494: /*@
3495:    SNESGetForceIteration - Whether or not to force SNESSolve() take at least one iteration regardless of the initial residual norm

3497:    Logically Collective on SNES

3499:    Input Parameters:
3500: .  snes - the SNES context

3502:    Output Parameter:
3503: .  force - PETSC_TRUE requires at least one iteration.

3505:    Level: intermediate

3507: .seealso: SNESSetForceIteration(), SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3508: @*/
3509: PetscErrorCode  SNESGetForceIteration(SNES snes,PetscBool *force)
3510: {
3513:   *force = snes->forceiteration;
3514:   return(0);
3515: }

3517: /*@
3518:    SNESSetTolerances - Sets various parameters used in convergence tests.

3520:    Logically Collective on SNES

3522:    Input Parameters:
3523: +  snes - the SNES context
3524: .  abstol - absolute convergence tolerance
3525: .  rtol - relative convergence tolerance
3526: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3527: .  maxit - maximum number of iterations
3528: -  maxf - maximum number of function evaluations (-1 indicates no limit)

3530:    Options Database Keys:
3531: +    -snes_atol <abstol> - Sets abstol
3532: .    -snes_rtol <rtol> - Sets rtol
3533: .    -snes_stol <stol> - Sets stol
3534: .    -snes_max_it <maxit> - Sets maxit
3535: -    -snes_max_funcs <maxf> - Sets maxf

3537:    Notes:
3538:    The default maximum number of iterations is 50.
3539:    The default maximum number of function evaluations is 1000.

3541:    Level: intermediate

3543: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance(), SNESSetForceIteration()
3544: @*/
3545: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3546: {

3555:   if (abstol != PETSC_DEFAULT) {
3556:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3557:     snes->abstol = abstol;
3558:   }
3559:   if (rtol != PETSC_DEFAULT) {
3560:     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);
3561:     snes->rtol = rtol;
3562:   }
3563:   if (stol != PETSC_DEFAULT) {
3564:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3565:     snes->stol = stol;
3566:   }
3567:   if (maxit != PETSC_DEFAULT) {
3568:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3569:     snes->max_its = maxit;
3570:   }
3571:   if (maxf != PETSC_DEFAULT) {
3572:     if (maxf < -1) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be -1 or nonnegative",maxf);
3573:     snes->max_funcs = maxf;
3574:   }
3575:   snes->tolerancesset = PETSC_TRUE;
3576:   return(0);
3577: }

3579: /*@
3580:    SNESSetDivergenceTolerance - Sets the divergence tolerance used for the SNES divergence test.

3582:    Logically Collective on SNES

3584:    Input Parameters:
3585: +  snes - the SNES context
3586: -  divtol - the divergence tolerance. Use -1 to deactivate the test.

3588:    Options Database Keys:
3589: .    -snes_divergence_tolerance <divtol> - Sets divtol

3591:    Notes:
3592:    The default divergence tolerance is 1e4.

3594:    Level: intermediate

3596: .seealso: SNESSetTolerances(), SNESGetDivergenceTolerance
3597: @*/
3598: PetscErrorCode  SNESSetDivergenceTolerance(SNES snes,PetscReal divtol)
3599: {

3604:   if (divtol != PETSC_DEFAULT) {
3605:     snes->divtol = divtol;
3606:   }
3607:   else {
3608:     snes->divtol = 1.0e4;
3609:   }
3610:   return(0);
3611: }

3613: /*@
3614:    SNESGetTolerances - Gets various parameters used in convergence tests.

3616:    Not Collective

3618:    Input Parameters:
3619: +  snes - the SNES context
3620: .  atol - absolute convergence tolerance
3621: .  rtol - relative convergence tolerance
3622: .  stol -  convergence tolerance in terms of the norm
3623:            of the change in the solution between steps
3624: .  maxit - maximum number of iterations
3625: -  maxf - maximum number of function evaluations

3627:    Notes:
3628:    The user can specify NULL for any parameter that is not needed.

3630:    Level: intermediate

3632: .seealso: SNESSetTolerances()
3633: @*/
3634: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3635: {
3638:   if (atol)  *atol  = snes->abstol;
3639:   if (rtol)  *rtol  = snes->rtol;
3640:   if (stol)  *stol  = snes->stol;
3641:   if (maxit) *maxit = snes->max_its;
3642:   if (maxf)  *maxf  = snes->max_funcs;
3643:   return(0);
3644: }

3646: /*@
3647:    SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.

3649:    Not Collective

3651:    Input Parameters:
3652: +  snes - the SNES context
3653: -  divtol - divergence tolerance

3655:    Level: intermediate

3657: .seealso: SNESSetDivergenceTolerance()
3658: @*/
3659: PetscErrorCode  SNESGetDivergenceTolerance(SNES snes,PetscReal *divtol)
3660: {
3663:   if (divtol) *divtol = snes->divtol;
3664:   return(0);
3665: }

3667: /*@
3668:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3670:    Logically Collective on SNES

3672:    Input Parameters:
3673: +  snes - the SNES context
3674: -  tol - tolerance

3676:    Options Database Key:
3677: .  -snes_trtol <tol> - Sets tol

3679:    Level: intermediate

3681: .seealso: SNESSetTolerances()
3682: @*/
3683: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3684: {
3688:   snes->deltatol = tol;
3689:   return(0);
3690: }

3692: /*
3693:    Duplicate the lg monitors for SNES from KSP; for some reason with
3694:    dynamic libraries things don't work under Sun4 if we just use
3695:    macros instead of functions
3696: */
3697: PetscErrorCode  SNESMonitorLGResidualNorm(SNES snes,PetscInt it,PetscReal norm,void *ctx)
3698: {

3703:   KSPMonitorLGResidualNorm((KSP)snes,it,norm,ctx);
3704:   return(0);
3705: }

3707: PetscErrorCode  SNESMonitorLGCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscDrawLG *lgctx)
3708: {

3712:   KSPMonitorLGResidualNormCreate(comm,host,label,x,y,m,n,lgctx);
3713:   return(0);
3714: }

3716: PETSC_INTERN PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);

3718: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3719: {
3720:   PetscDrawLG      lg;
3721:   PetscErrorCode   ierr;
3722:   PetscReal        x,y,per;
3723:   PetscViewer      v = (PetscViewer)monctx;
3724:   static PetscReal prev; /* should be in the context */
3725:   PetscDraw        draw;

3729:   PetscViewerDrawGetDrawLG(v,0,&lg);
3730:   if (!n) {PetscDrawLGReset(lg);}
3731:   PetscDrawLGGetDraw(lg,&draw);
3732:   PetscDrawSetTitle(draw,"Residual norm");
3733:   x    = (PetscReal)n;
3734:   if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3735:   else y = -15.0;
3736:   PetscDrawLGAddPoint(lg,&x,&y);
3737:   if (n < 20 || !(n % 5) || snes->reason) {
3738:     PetscDrawLGDraw(lg);
3739:     PetscDrawLGSave(lg);
3740:   }

3742:   PetscViewerDrawGetDrawLG(v,1,&lg);
3743:   if (!n) {PetscDrawLGReset(lg);}
3744:   PetscDrawLGGetDraw(lg,&draw);
3745:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3746:    SNESMonitorRange_Private(snes,n,&per);
3747:   x    = (PetscReal)n;
3748:   y    = 100.0*per;
3749:   PetscDrawLGAddPoint(lg,&x,&y);
3750:   if (n < 20 || !(n % 5) || snes->reason) {
3751:     PetscDrawLGDraw(lg);
3752:     PetscDrawLGSave(lg);
3753:   }

3755:   PetscViewerDrawGetDrawLG(v,2,&lg);
3756:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3757:   PetscDrawLGGetDraw(lg,&draw);
3758:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3759:   x    = (PetscReal)n;
3760:   y    = (prev - rnorm)/prev;
3761:   PetscDrawLGAddPoint(lg,&x,&y);
3762:   if (n < 20 || !(n % 5) || snes->reason) {
3763:     PetscDrawLGDraw(lg);
3764:     PetscDrawLGSave(lg);
3765:   }

3767:   PetscViewerDrawGetDrawLG(v,3,&lg);
3768:   if (!n) {PetscDrawLGReset(lg);}
3769:   PetscDrawLGGetDraw(lg,&draw);
3770:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3771:   x    = (PetscReal)n;
3772:   y    = (prev - rnorm)/(prev*per);
3773:   if (n > 2) { /*skip initial crazy value */
3774:     PetscDrawLGAddPoint(lg,&x,&y);
3775:   }
3776:   if (n < 20 || !(n % 5) || snes->reason) {
3777:     PetscDrawLGDraw(lg);
3778:     PetscDrawLGSave(lg);
3779:   }
3780:   prev = rnorm;
3781:   return(0);
3782: }

3784: /*@
3785:    SNESMonitor - runs the user provided monitor routines, if they exist

3787:    Collective on SNES

3789:    Input Parameters:
3790: +  snes - nonlinear solver context obtained from SNESCreate()
3791: .  iter - iteration number
3792: -  rnorm - relative norm of the residual

3794:    Notes:
3795:    This routine is called by the SNES implementations.
3796:    It does not typically need to be called by the user.

3798:    Level: developer

3800: .seealso: SNESMonitorSet()
3801: @*/
3802: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3803: {
3805:   PetscInt       i,n = snes->numbermonitors;

3808:   VecLockReadPush(snes->vec_sol);
3809:   for (i=0; i<n; i++) {
3810:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3811:   }
3812:   VecLockReadPop(snes->vec_sol);
3813:   return(0);
3814: }

3816: /* ------------ Routines to set performance monitoring options ----------- */

3818: /*MC
3819:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3821:      Synopsis:
3822:      #include <petscsnes.h>
3823: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3825: +    snes - the SNES context
3826: .    its - iteration number
3827: .    norm - 2-norm function value (may be estimated)
3828: -    mctx - [optional] monitoring context

3830:    Level: advanced

3832: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3833: M*/

3835: /*@C
3836:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3837:    iteration of the nonlinear solver to display the iteration's
3838:    progress.

3840:    Logically Collective on SNES

3842:    Input Parameters:
3843: +  snes - the SNES context
3844: .  f - the monitor function, see SNESMonitorFunction for the calling sequence
3845: .  mctx - [optional] user-defined context for private data for the
3846:           monitor routine (use NULL if no context is desired)
3847: -  monitordestroy - [optional] routine that frees monitor context
3848:           (may be NULL)

3850:    Options Database Keys:
3851: +    -snes_monitor        - sets SNESMonitorDefault()
3852: .    -snes_monitor_lg_residualnorm    - sets line graph monitor,
3853:                             uses SNESMonitorLGCreate()
3854: -    -snes_monitor_cancel - cancels all monitors that have
3855:                             been hardwired into a code by
3856:                             calls to SNESMonitorSet(), but
3857:                             does not cancel those set via
3858:                             the options database.

3860:    Notes:
3861:    Several different monitoring routines may be set by calling
3862:    SNESMonitorSet() multiple times; all will be called in the
3863:    order in which they were set.

3865:    Fortran Notes:
3866:     Only a single monitor function can be set for each SNES object

3868:    Level: intermediate

3870: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3871: @*/
3872: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*f)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3873: {
3874:   PetscInt       i;
3876:   PetscBool      identical;

3880:   for (i=0; i<snes->numbermonitors;i++) {
3881:     PetscMonitorCompare((PetscErrorCode (*)(void))f,mctx,monitordestroy,(PetscErrorCode (*)(void))snes->monitor[i],snes->monitorcontext[i],snes->monitordestroy[i],&identical);
3882:     if (identical) return(0);
3883:   }
3884:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3885:   snes->monitor[snes->numbermonitors]          = f;
3886:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3887:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3888:   return(0);
3889: }

3891: /*@
3892:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3894:    Logically Collective on SNES

3896:    Input Parameters:
3897: .  snes - the SNES context

3899:    Options Database Key:
3900: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
3901:     into a code by calls to SNESMonitorSet(), but does not cancel those
3902:     set via the options database

3904:    Notes:
3905:    There is no way to clear one specific monitor from a SNES object.

3907:    Level: intermediate

3909: .seealso: SNESMonitorDefault(), SNESMonitorSet()
3910: @*/
3911: PetscErrorCode  SNESMonitorCancel(SNES snes)
3912: {
3914:   PetscInt       i;

3918:   for (i=0; i<snes->numbermonitors; i++) {
3919:     if (snes->monitordestroy[i]) {
3920:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
3921:     }
3922:   }
3923:   snes->numbermonitors = 0;
3924:   return(0);
3925: }

3927: /*MC
3928:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

3930:      Synopsis:
3931:      #include <petscsnes.h>
3932: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

3934: +    snes - the SNES context
3935: .    it - current iteration (0 is the first and is before any Newton step)
3936: .    cctx - [optional] convergence context
3937: .    reason - reason for convergence/divergence
3938: .    xnorm - 2-norm of current iterate
3939: .    gnorm - 2-norm of current step
3940: -    f - 2-norm of function

3942:    Level: intermediate

3944: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
3945: M*/

3947: /*@C
3948:    SNESSetConvergenceTest - Sets the function that is to be used
3949:    to test for convergence of the nonlinear iterative solution.

3951:    Logically Collective on SNES

3953:    Input Parameters:
3954: +  snes - the SNES context
3955: .  SNESConvergenceTestFunction - routine to test for convergence
3956: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
3957: -  destroy - [optional] destructor for the context (may be NULL; PETSC_NULL_FUNCTION in Fortran)

3959:    Level: advanced

3961: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
3962: @*/
3963: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
3964: {

3969:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
3970:   if (snes->ops->convergeddestroy) {
3971:     (*snes->ops->convergeddestroy)(snes->cnvP);
3972:   }
3973:   snes->ops->converged        = SNESConvergenceTestFunction;
3974:   snes->ops->convergeddestroy = destroy;
3975:   snes->cnvP                  = cctx;
3976:   return(0);
3977: }

3979: /*@
3980:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

3982:    Not Collective

3984:    Input Parameter:
3985: .  snes - the SNES context

3987:    Output Parameter:
3988: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3989:             manual pages for the individual convergence tests for complete lists

3991:    Options Database:
3992: .   -snes_converged_reason - prints the reason to standard out

3994:    Level: intermediate

3996:    Notes:
3997:     Should only be called after the call the SNESSolve() is complete, if it is called earlier it returns the value SNES__CONVERGED_ITERATING.

3999: .seealso: SNESSetConvergenceTest(), SNESSetConvergedReason(), SNESConvergedReason
4000: @*/
4001: PetscErrorCode SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
4002: {
4006:   *reason = snes->reason;
4007:   return(0);
4008: }

4010: /*@
4011:    SNESSetConvergedReason - Sets the reason the SNES iteration was stopped.

4013:    Not Collective

4015:    Input Parameters:
4016: +  snes - the SNES context
4017: -  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
4018:             manual pages for the individual convergence tests for complete lists

4020:    Level: intermediate

4022: .seealso: SNESGetConvergedReason(), SNESSetConvergenceTest(), SNESConvergedReason
4023: @*/
4024: PetscErrorCode SNESSetConvergedReason(SNES snes,SNESConvergedReason reason)
4025: {
4028:   snes->reason = reason;
4029:   return(0);
4030: }

4032: /*@
4033:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

4035:    Logically Collective on SNES

4037:    Input Parameters:
4038: +  snes - iterative context obtained from SNESCreate()
4039: .  a   - array to hold history, this array will contain the function norms computed at each step
4040: .  its - integer array holds the number of linear iterations for each solve.
4041: .  na  - size of a and its
4042: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
4043:            else it continues storing new values for new nonlinear solves after the old ones

4045:    Notes:
4046:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
4047:    default array of length 10000 is allocated.

4049:    This routine is useful, e.g., when running a code for purposes
4050:    of accurate performance monitoring, when no I/O should be done
4051:    during the section of code that is being timed.

4053:    Level: intermediate

4055: .seealso: SNESGetConvergenceHistory()

4057: @*/
4058: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
4059: {

4066:   if (!a) {
4067:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
4068:     PetscCalloc2(na,&a,na,&its);
4069:     snes->conv_hist_alloc = PETSC_TRUE;
4070:   }
4071:   snes->conv_hist       = a;
4072:   snes->conv_hist_its   = its;
4073:   snes->conv_hist_max   = na;
4074:   snes->conv_hist_len   = 0;
4075:   snes->conv_hist_reset = reset;
4076:   return(0);
4077: }

4079: #if defined(PETSC_HAVE_MATLAB_ENGINE)
4080: #include <engine.h>   /* MATLAB include file */
4081: #include <mex.h>      /* MATLAB include file */

4083: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4084: {
4085:   mxArray   *mat;
4086:   PetscInt  i;
4087:   PetscReal *ar;

4090:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
4091:   ar  = (PetscReal*) mxGetData(mat);
4092:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4093:   PetscFunctionReturn(mat);
4094: }
4095: #endif

4097: /*@C
4098:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

4100:    Not Collective

4102:    Input Parameter:
4103: .  snes - iterative context obtained from SNESCreate()

4105:    Output Parameters:
4106: +  a   - array to hold history
4107: .  its - integer array holds the number of linear iterations (or
4108:          negative if not converged) for each solve.
4109: -  na  - size of a and its

4111:    Notes:
4112:     The calling sequence for this routine in Fortran is
4113: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

4115:    This routine is useful, e.g., when running a code for purposes
4116:    of accurate performance monitoring, when no I/O should be done
4117:    during the section of code that is being timed.

4119:    Level: intermediate

4121: .seealso: SNESSetConvergencHistory()

4123: @*/
4124: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
4125: {
4128:   if (a)   *a   = snes->conv_hist;
4129:   if (its) *its = snes->conv_hist_its;
4130:   if (na)  *na  = snes->conv_hist_len;
4131:   return(0);
4132: }

4134: /*@C
4135:   SNESSetUpdate - Sets the general-purpose update function called
4136:   at the beginning of every iteration of the nonlinear solve. Specifically
4137:   it is called just before the Jacobian is "evaluated".

4139:   Logically Collective on SNES

4141:   Input Parameters:
4142: + snes - The nonlinear solver context
4143: - func - The function

4145:   Calling sequence of func:
4146: $ func (SNES snes, PetscInt step);

4148: . step - The current step of the iteration

4150:   Level: advanced

4152:   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()
4153:         This is not used by most users.

4155: .seealso SNESSetJacobian(), SNESSolve()
4156: @*/
4157: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
4158: {
4161:   snes->ops->update = func;
4162:   return(0);
4163: }

4165: /*
4166:    SNESScaleStep_Private - Scales a step so that its length is less than the
4167:    positive parameter delta.

4169:     Input Parameters:
4170: +   snes - the SNES context
4171: .   y - approximate solution of linear system
4172: .   fnorm - 2-norm of current function
4173: -   delta - trust region size

4175:     Output Parameters:
4176: +   gpnorm - predicted function norm at the new point, assuming local
4177:     linearization.  The value is zero if the step lies within the trust
4178:     region, and exceeds zero otherwise.
4179: -   ynorm - 2-norm of the step

4181:     Note:
4182:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
4183:     is set to be the maximum allowable step size.

4185: */
4186: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
4187: {
4188:   PetscReal      nrm;
4189:   PetscScalar    cnorm;


4197:   VecNorm(y,NORM_2,&nrm);
4198:   if (nrm > *delta) {
4199:     nrm     = *delta/nrm;
4200:     *gpnorm = (1.0 - nrm)*(*fnorm);
4201:     cnorm   = nrm;
4202:     VecScale(y,cnorm);
4203:     *ynorm  = *delta;
4204:   } else {
4205:     *gpnorm = 0.0;
4206:     *ynorm  = nrm;
4207:   }
4208:   return(0);
4209: }

4211: /*@
4212:    SNESReasonView - Displays the reason a SNES solve converged or diverged to a viewer

4214:    Collective on SNES

4216:    Parameter:
4217: +  snes - iterative context obtained from SNESCreate()
4218: -  viewer - the viewer to display the reason


4221:    Options Database Keys:
4222: .  -snes_converged_reason - print reason for converged or diverged, also prints number of iterations

4224:    Level: beginner

4226: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault()

4228: @*/
4229: PetscErrorCode  SNESReasonView(SNES snes,PetscViewer viewer)
4230: {
4231:   PetscViewerFormat format;
4232:   PetscBool         isAscii;
4233:   PetscErrorCode    ierr;

4236:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isAscii);
4237:   if (isAscii) {
4238:     PetscViewerGetFormat(viewer, &format);
4239:     PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);
4240:     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4241:       DM                dm;
4242:       Vec               u;
4243:       PetscDS           prob;
4244:       PetscInt          Nf, f;
4245:       PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4246:       void            **exactCtx;
4247:       PetscReal         error;

4249:       SNESGetDM(snes, &dm);
4250:       SNESGetSolution(snes, &u);
4251:       DMGetDS(dm, &prob);
4252:       PetscDSGetNumFields(prob, &Nf);
4253:       PetscMalloc2(Nf, &exactSol, Nf, &exactCtx);
4254:       for (f = 0; f < Nf; ++f) {PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]);}
4255:       DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error);
4256:       PetscFree2(exactSol, exactCtx);
4257:       if (error < 1.0e-11) {PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n");}
4258:       else                 {PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", error);}
4259:     }
4260:     if (snes->reason > 0) {
4261:       if (((PetscObject) snes)->prefix) {
4262:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve converged due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4263:       } else {
4264:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4265:       }
4266:     } else {
4267:       if (((PetscObject) snes)->prefix) {
4268:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve did not converge due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4269:       } else {
4270:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4271:       }
4272:     }
4273:     PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);
4274:   }
4275:   return(0);
4276: }

4278: /*@C
4279:   SNESReasonViewFromOptions - Processes command line options to determine if/how a SNESReason is to be viewed.

4281:   Collective on SNES

4283:   Input Parameters:
4284: . snes   - the SNES object

4286:   Level: intermediate

4288: @*/
4289: PetscErrorCode SNESReasonViewFromOptions(SNES snes)
4290: {
4291:   PetscErrorCode    ierr;
4292:   PetscViewer       viewer;
4293:   PetscBool         flg;
4294:   static PetscBool  incall = PETSC_FALSE;
4295:   PetscViewerFormat format;

4298:   if (incall) return(0);
4299:   incall = PETSC_TRUE;
4300:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_converged_reason",&viewer,&format,&flg);
4301:   if (flg) {
4302:     PetscViewerPushFormat(viewer,format);
4303:     SNESReasonView(snes,viewer);
4304:     PetscViewerPopFormat(viewer);
4305:     PetscViewerDestroy(&viewer);
4306:   }
4307:   incall = PETSC_FALSE;
4308:   return(0);
4309: }

4311: /*@
4312:    SNESSolve - Solves a nonlinear system F(x) = b.
4313:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

4315:    Collective on SNES

4317:    Input Parameters:
4318: +  snes - the SNES context
4319: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
4320: -  x - the solution vector.

4322:    Notes:
4323:    The user should initialize the vector,x, with the initial guess
4324:    for the nonlinear solve prior to calling SNESSolve.  In particular,
4325:    to employ an initial guess of zero, the user should explicitly set
4326:    this vector to zero by calling VecSet().

4328:    Level: beginner

4330: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
4331: @*/
4332: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
4333: {
4334:   PetscErrorCode    ierr;
4335:   PetscBool         flg;
4336:   PetscInt          grid;
4337:   Vec               xcreated = NULL;
4338:   DM                dm;


4347:   /* High level operations using the nonlinear solver */
4348:   {
4349:     PetscViewer       viewer;
4350:     PetscViewerFormat format;
4351:     PetscInt          num;
4352:     PetscBool         flg;
4353:     static PetscBool  incall = PETSC_FALSE;

4355:     if (!incall) {
4356:       /* Estimate the convergence rate of the discretization */
4357:       PetscOptionsGetViewer(PetscObjectComm((PetscObject) snes),((PetscObject)snes)->options, ((PetscObject) snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg);
4358:       if (flg) {
4359:         PetscConvEst conv;
4360:         DM           dm;
4361:         PetscReal   *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4362:         PetscInt     Nf;

4364:         incall = PETSC_TRUE;
4365:         SNESGetDM(snes, &dm);
4366:         DMGetNumFields(dm, &Nf);
4367:         PetscCalloc1(Nf, &alpha);
4368:         PetscConvEstCreate(PetscObjectComm((PetscObject) snes), &conv);
4369:         PetscConvEstSetSolver(conv, snes);
4370:         PetscConvEstSetFromOptions(conv);
4371:         PetscConvEstSetUp(conv);
4372:         PetscConvEstGetConvRate(conv, alpha);
4373:         PetscViewerPushFormat(viewer, format);
4374:         PetscConvEstRateView(conv, alpha, viewer);
4375:         PetscViewerPopFormat(viewer);
4376:         PetscViewerDestroy(&viewer);
4377:         PetscConvEstDestroy(&conv);
4378:         PetscFree(alpha);
4379:         incall = PETSC_FALSE;
4380:       }
4381:       /* Adaptively refine the initial grid */
4382:       num  = 1;
4383:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_initial", &num, &flg);
4384:       if (flg) {
4385:         DMAdaptor adaptor;

4387:         incall = PETSC_TRUE;
4388:         DMAdaptorCreate(PETSC_COMM_WORLD, &adaptor);
4389:         DMAdaptorSetSolver(adaptor, snes);
4390:         DMAdaptorSetSequenceLength(adaptor, num);
4391:         DMAdaptorSetFromOptions(adaptor);
4392:         DMAdaptorSetUp(adaptor);
4393:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x);
4394:         DMAdaptorDestroy(&adaptor);
4395:         incall = PETSC_FALSE;
4396:       }
4397:       /* Use grid sequencing to adapt */
4398:       num  = 0;
4399:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_sequence", &num, NULL);
4400:       if (num) {
4401:         DMAdaptor adaptor;

4403:         incall = PETSC_TRUE;
4404:         DMAdaptorCreate(PETSC_COMM_WORLD, &adaptor);
4405:         DMAdaptorSetSolver(adaptor, snes);
4406:         DMAdaptorSetSequenceLength(adaptor, num);
4407:         DMAdaptorSetFromOptions(adaptor);
4408:         DMAdaptorSetUp(adaptor);
4409:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x);
4410:         DMAdaptorDestroy(&adaptor);
4411:         incall = PETSC_FALSE;
4412:       }
4413:     }
4414:   }
4415:   if (!x) {
4416:     SNESGetDM(snes,&dm);
4417:     DMCreateGlobalVector(dm,&xcreated);
4418:     x    = xcreated;
4419:   }
4420:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

4422:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
4423:   for (grid=0; grid<snes->gridsequence+1; grid++) {

4425:     /* set solution vector */
4426:     if (!grid) {PetscObjectReference((PetscObject)x);}
4427:     VecDestroy(&snes->vec_sol);
4428:     snes->vec_sol = x;
4429:     SNESGetDM(snes,&dm);

4431:     /* set affine vector if provided */
4432:     if (b) { PetscObjectReference((PetscObject)b); }
4433:     VecDestroy(&snes->vec_rhs);
4434:     snes->vec_rhs = b;

4436:     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");
4437:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
4438:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
4439:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
4440:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
4441:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
4442:     }
4443:     DMShellSetGlobalVector(dm,snes->vec_sol);
4444:     SNESSetUp(snes);

4446:     if (!grid) {
4447:       if (snes->ops->computeinitialguess) {
4448:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
4449:       }
4450:     }

4452:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4453:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

4455:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
4456:     (*snes->ops->solve)(snes);
4457:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
4458:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");
4459:     snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */

4461:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4462:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

4464:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_test_local_min",NULL,NULL,&flg);
4465:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
4466:     SNESReasonViewFromOptions(snes);

4468:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
4469:     if (snes->reason < 0) break;
4470:     if (grid <  snes->gridsequence) {
4471:       DM  fine;
4472:       Vec xnew;
4473:       Mat interp;

4475:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
4476:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
4477:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
4478:       DMCreateGlobalVector(fine,&xnew);
4479:       MatInterpolate(interp,x,xnew);
4480:       DMInterpolate(snes->dm,interp,fine);
4481:       MatDestroy(&interp);
4482:       x    = xnew;

4484:       SNESReset(snes);
4485:       SNESSetDM(snes,fine);
4486:       SNESResetFromOptions(snes);
4487:       DMDestroy(&fine);
4488:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
4489:     }
4490:   }
4491:   SNESViewFromOptions(snes,NULL,"-snes_view");
4492:   VecViewFromOptions(snes->vec_sol,(PetscObject)snes,"-snes_view_solution");

4494:   VecDestroy(&xcreated);
4495:   PetscObjectSAWsBlock((PetscObject)snes);
4496:   return(0);
4497: }

4499: /* --------- Internal routines for SNES Package --------- */

4501: /*@C
4502:    SNESSetType - Sets the method for the nonlinear solver.

4504:    Collective on SNES

4506:    Input Parameters:
4507: +  snes - the SNES context
4508: -  type - a known method

4510:    Options Database Key:
4511: .  -snes_type <type> - Sets the method; use -help for a list
4512:    of available methods (for instance, newtonls or newtontr)

4514:    Notes:
4515:    See "petsc/include/petscsnes.h" for available methods (for instance)
4516: +    SNESNEWTONLS - Newton's method with line search
4517:      (systems of nonlinear equations)
4518: -    SNESNEWTONTR - Newton's method with trust region
4519:      (systems of nonlinear equations)

4521:   Normally, it is best to use the SNESSetFromOptions() command and then
4522:   set the SNES solver type from the options database rather than by using
4523:   this routine.  Using the options database provides the user with
4524:   maximum flexibility in evaluating the many nonlinear solvers.
4525:   The SNESSetType() routine is provided for those situations where it
4526:   is necessary to set the nonlinear solver independently of the command
4527:   line or options database.  This might be the case, for example, when
4528:   the choice of solver changes during the execution of the program,
4529:   and the user's application is taking responsibility for choosing the
4530:   appropriate method.

4532:     Developer Notes:
4533:     SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
4534:     the constructor in that list and calls it to create the spexific object.

4536:   Level: intermediate

4538: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

4540: @*/
4541: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
4542: {
4543:   PetscErrorCode ierr,(*r)(SNES);
4544:   PetscBool      match;


4550:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
4551:   if (match) return(0);

4553:   PetscFunctionListFind(SNESList,type,&r);
4554:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
4555:   /* Destroy the previous private SNES context */
4556:   if (snes->ops->destroy) {
4557:     (*(snes)->ops->destroy)(snes);
4558:     snes->ops->destroy = NULL;
4559:   }
4560:   /* Reinitialize function pointers in SNESOps structure */
4561:   snes->ops->setup          = 0;
4562:   snes->ops->solve          = 0;
4563:   snes->ops->view           = 0;
4564:   snes->ops->setfromoptions = 0;
4565:   snes->ops->destroy        = 0;

4567:   /* It may happen the user has customized the line search before calling SNESSetType */
4568:   if (((PetscObject)snes)->type_name) {
4569:     SNESLineSearchDestroy(&snes->linesearch);
4570:   }

4572:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4573:   snes->setupcalled = PETSC_FALSE;

4575:   PetscObjectChangeTypeName((PetscObject)snes,type);
4576:   (*r)(snes);
4577:   return(0);
4578: }

4580: /*@C
4581:    SNESGetType - Gets the SNES method type and name (as a string).

4583:    Not Collective

4585:    Input Parameter:
4586: .  snes - nonlinear solver context

4588:    Output Parameter:
4589: .  type - SNES method (a character string)

4591:    Level: intermediate

4593: @*/
4594: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
4595: {
4599:   *type = ((PetscObject)snes)->type_name;
4600:   return(0);
4601: }

4603: /*@
4604:   SNESSetSolution - Sets the solution vector for use by the SNES routines.

4606:   Logically Collective on SNES

4608:   Input Parameters:
4609: + snes - the SNES context obtained from SNESCreate()
4610: - u    - the solution vector

4612:   Level: beginner

4614: @*/
4615: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4616: {
4617:   DM             dm;

4623:   PetscObjectReference((PetscObject) u);
4624:   VecDestroy(&snes->vec_sol);

4626:   snes->vec_sol = u;

4628:   SNESGetDM(snes, &dm);
4629:   DMShellSetGlobalVector(dm, u);
4630:   return(0);
4631: }

4633: /*@
4634:    SNESGetSolution - Returns the vector where the approximate solution is
4635:    stored. This is the fine grid solution when using SNESSetGridSequence().

4637:    Not Collective, but Vec is parallel if SNES is parallel

4639:    Input Parameter:
4640: .  snes - the SNES context

4642:    Output Parameter:
4643: .  x - the solution

4645:    Level: intermediate

4647: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
4648: @*/
4649: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
4650: {
4654:   *x = snes->vec_sol;
4655:   return(0);
4656: }

4658: /*@
4659:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4660:    stored.

4662:    Not Collective, but Vec is parallel if SNES is parallel

4664:    Input Parameter:
4665: .  snes - the SNES context

4667:    Output Parameter:
4668: .  x - the solution update

4670:    Level: advanced

4672: .seealso: SNESGetSolution(), SNESGetFunction()
4673: @*/
4674: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4675: {
4679:   *x = snes->vec_sol_update;
4680:   return(0);
4681: }

4683: /*@C
4684:    SNESGetFunction - Returns the vector where the function is stored.

4686:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4688:    Input Parameter:
4689: .  snes - the SNES context

4691:    Output Parameter:
4692: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4693: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4694: -  ctx - the function context (or NULL if you don't want it)

4696:    Level: advanced

4698:     Notes: The vector r DOES NOT, in general contain the current value of the SNES nonlinear function

4700: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4701: @*/
4702: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4703: {
4705:   DM             dm;

4709:   if (r) {
4710:     if (!snes->vec_func) {
4711:       if (snes->vec_rhs) {
4712:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4713:       } else if (snes->vec_sol) {
4714:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4715:       } else if (snes->dm) {
4716:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4717:       }
4718:     }
4719:     *r = snes->vec_func;
4720:   }
4721:   SNESGetDM(snes,&dm);
4722:   DMSNESGetFunction(dm,f,ctx);
4723:   return(0);
4724: }

4726: /*@C
4727:    SNESGetNGS - Returns the NGS function and context.

4729:    Input Parameter:
4730: .  snes - the SNES context

4732:    Output Parameter:
4733: +  f - the function (or NULL) see SNESNGSFunction for details
4734: -  ctx    - the function context (or NULL)

4736:    Level: advanced

4738: .seealso: SNESSetNGS(), SNESGetFunction()
4739: @*/

4741: PetscErrorCode SNESGetNGS (SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void*), void ** ctx)
4742: {
4744:   DM             dm;

4748:   SNESGetDM(snes,&dm);
4749:   DMSNESGetNGS(dm,f,ctx);
4750:   return(0);
4751: }

4753: /*@C
4754:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4755:    SNES options in the database.

4757:    Logically Collective on SNES

4759:    Input Parameter:
4760: +  snes - the SNES context
4761: -  prefix - the prefix to prepend to all option names

4763:    Notes:
4764:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4765:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4767:    Level: advanced

4769: .seealso: SNESSetFromOptions()
4770: @*/
4771: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4772: {

4777:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4778:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4779:   if (snes->linesearch) {
4780:     SNESGetLineSearch(snes,&snes->linesearch);
4781:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4782:   }
4783:   KSPSetOptionsPrefix(snes->ksp,prefix);
4784:   return(0);
4785: }

4787: /*@C
4788:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4789:    SNES options in the database.

4791:    Logically Collective on SNES

4793:    Input Parameters:
4794: +  snes - the SNES context
4795: -  prefix - the prefix to prepend to all option names

4797:    Notes:
4798:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4799:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4801:    Level: advanced

4803: .seealso: SNESGetOptionsPrefix()
4804: @*/
4805: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
4806: {

4811:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
4812:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4813:   if (snes->linesearch) {
4814:     SNESGetLineSearch(snes,&snes->linesearch);
4815:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
4816:   }
4817:   KSPAppendOptionsPrefix(snes->ksp,prefix);
4818:   return(0);
4819: }

4821: /*@C
4822:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
4823:    SNES options in the database.

4825:    Not Collective

4827:    Input Parameter:
4828: .  snes - the SNES context

4830:    Output Parameter:
4831: .  prefix - pointer to the prefix string used

4833:    Notes:
4834:     On the fortran side, the user should pass in a string 'prefix' of
4835:    sufficient length to hold the prefix.

4837:    Level: advanced

4839: .seealso: SNESAppendOptionsPrefix()
4840: @*/
4841: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
4842: {

4847:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
4848:   return(0);
4849: }


4852: /*@C
4853:   SNESRegister - Adds a method to the nonlinear solver package.

4855:    Not collective

4857:    Input Parameters:
4858: +  name_solver - name of a new user-defined solver
4859: -  routine_create - routine to create method context

4861:    Notes:
4862:    SNESRegister() may be called multiple times to add several user-defined solvers.

4864:    Sample usage:
4865: .vb
4866:    SNESRegister("my_solver",MySolverCreate);
4867: .ve

4869:    Then, your solver can be chosen with the procedural interface via
4870: $     SNESSetType(snes,"my_solver")
4871:    or at runtime via the option
4872: $     -snes_type my_solver

4874:    Level: advanced

4876:     Note: If your function is not being put into a shared library then use SNESRegister() instead

4878: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

4880:   Level: advanced
4881: @*/
4882: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
4883: {

4887:   SNESInitializePackage();
4888:   PetscFunctionListAdd(&SNESList,sname,function);
4889:   return(0);
4890: }

4892: PetscErrorCode  SNESTestLocalMin(SNES snes)
4893: {
4895:   PetscInt       N,i,j;
4896:   Vec            u,uh,fh;
4897:   PetscScalar    value;
4898:   PetscReal      norm;

4901:   SNESGetSolution(snes,&u);
4902:   VecDuplicate(u,&uh);
4903:   VecDuplicate(u,&fh);

4905:   /* currently only works for sequential */
4906:   PetscPrintf(PETSC_COMM_WORLD,"Testing FormFunction() for local min\n");
4907:   VecGetSize(u,&N);
4908:   for (i=0; i<N; i++) {
4909:     VecCopy(u,uh);
4910:     PetscPrintf(PETSC_COMM_WORLD,"i = %D\n",i);
4911:     for (j=-10; j<11; j++) {
4912:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
4913:       VecSetValue(uh,i,value,ADD_VALUES);
4914:       SNESComputeFunction(snes,uh,fh);
4915:       VecNorm(fh,NORM_2,&norm);
4916:       PetscPrintf(PETSC_COMM_WORLD,"       j norm %D %18.16e\n",j,norm);
4917:       value = -value;
4918:       VecSetValue(uh,i,value,ADD_VALUES);
4919:     }
4920:   }
4921:   VecDestroy(&uh);
4922:   VecDestroy(&fh);
4923:   return(0);
4924: }

4926: /*@
4927:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
4928:    computing relative tolerance for linear solvers within an inexact
4929:    Newton method.

4931:    Logically Collective on SNES

4933:    Input Parameters:
4934: +  snes - SNES context
4935: -  flag - PETSC_TRUE or PETSC_FALSE

4937:     Options Database:
4938: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
4939: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
4940: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
4941: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
4942: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
4943: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
4944: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
4945: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

4947:    Notes:
4948:    Currently, the default is to use a constant relative tolerance for
4949:    the inner linear solvers.  Alternatively, one can use the
4950:    Eisenstat-Walker method, where the relative convergence tolerance
4951:    is reset at each Newton iteration according progress of the nonlinear
4952:    solver.

4954:    Level: advanced

4956:    Reference:
4957:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4958:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4960: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4961: @*/
4962: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
4963: {
4967:   snes->ksp_ewconv = flag;
4968:   return(0);
4969: }

4971: /*@
4972:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
4973:    for computing relative tolerance for linear solvers within an
4974:    inexact Newton method.

4976:    Not Collective

4978:    Input Parameter:
4979: .  snes - SNES context

4981:    Output Parameter:
4982: .  flag - PETSC_TRUE or PETSC_FALSE

4984:    Notes:
4985:    Currently, the default is to use a constant relative tolerance for
4986:    the inner linear solvers.  Alternatively, one can use the
4987:    Eisenstat-Walker method, where the relative convergence tolerance
4988:    is reset at each Newton iteration according progress of the nonlinear
4989:    solver.

4991:    Level: advanced

4993:    Reference:
4994:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4995:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4997: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4998: @*/
4999: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
5000: {
5004:   *flag = snes->ksp_ewconv;
5005:   return(0);
5006: }

5008: /*@
5009:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
5010:    convergence criteria for the linear solvers within an inexact
5011:    Newton method.

5013:    Logically Collective on SNES

5015:    Input Parameters:
5016: +    snes - SNES context
5017: .    version - version 1, 2 (default is 2) or 3
5018: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5019: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5020: .    gamma - multiplicative factor for version 2 rtol computation
5021:              (0 <= gamma2 <= 1)
5022: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
5023: .    alpha2 - power for safeguard
5024: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

5026:    Note:
5027:    Version 3 was contributed by Luis Chacon, June 2006.

5029:    Use PETSC_DEFAULT to retain the default for any of the parameters.

5031:    Level: advanced

5033:    Reference:
5034:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5035:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
5036:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

5038: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
5039: @*/
5040: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
5041: {
5042:   SNESKSPEW *kctx;

5046:   kctx = (SNESKSPEW*)snes->kspconvctx;
5047:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

5056:   if (version != PETSC_DEFAULT)   kctx->version   = version;
5057:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
5058:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
5059:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
5060:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
5061:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
5062:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

5064:   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);
5065:   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);
5066:   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);
5067:   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);
5068:   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);
5069:   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);
5070:   return(0);
5071: }

5073: /*@
5074:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5075:    convergence criteria for the linear solvers within an inexact
5076:    Newton method.

5078:    Not Collective

5080:    Input Parameters:
5081:      snes - SNES context

5083:    Output Parameters:
5084: +    version - version 1, 2 (default is 2) or 3
5085: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5086: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5087: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5088: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
5089: .    alpha2 - power for safeguard
5090: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

5092:    Level: advanced

5094: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
5095: @*/
5096: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
5097: {
5098:   SNESKSPEW *kctx;

5102:   kctx = (SNESKSPEW*)snes->kspconvctx;
5103:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
5104:   if (version)   *version   = kctx->version;
5105:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
5106:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
5107:   if (gamma)     *gamma     = kctx->gamma;
5108:   if (alpha)     *alpha     = kctx->alpha;
5109:   if (alpha2)    *alpha2    = kctx->alpha2;
5110:   if (threshold) *threshold = kctx->threshold;
5111:   return(0);
5112: }

5114:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5115: {
5117:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5118:   PetscReal      rtol  = PETSC_DEFAULT,stol;

5121:   if (!snes->ksp_ewconv) return(0);
5122:   if (!snes->iter) {
5123:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5124:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
5125:   }
5126:   else {
5127:     if (kctx->version == 1) {
5128:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
5129:       if (rtol < 0.0) rtol = -rtol;
5130:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
5131:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5132:     } else if (kctx->version == 2) {
5133:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5134:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
5135:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5136:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5137:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5138:       /* safeguard: avoid sharp decrease of rtol */
5139:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
5140:       stol = PetscMax(rtol,stol);
5141:       rtol = PetscMin(kctx->rtol_0,stol);
5142:       /* safeguard: avoid oversolving */
5143:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
5144:       stol = PetscMax(rtol,stol);
5145:       rtol = PetscMin(kctx->rtol_0,stol);
5146:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
5147:   }
5148:   /* safeguard: avoid rtol greater than one */
5149:   rtol = PetscMin(rtol,kctx->rtol_max);
5150:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
5151:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
5152:   return(0);
5153: }

5155: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5156: {
5158:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5159:   PCSide         pcside;
5160:   Vec            lres;

5163:   if (!snes->ksp_ewconv) return(0);
5164:   KSPGetTolerances(ksp,&kctx->rtol_last,0,0,0);
5165:   kctx->norm_last = snes->norm;
5166:   if (kctx->version == 1) {
5167:     PC        pc;
5168:     PetscBool isNone;

5170:     KSPGetPC(ksp, &pc);
5171:     PetscObjectTypeCompare((PetscObject) pc, PCNONE, &isNone);
5172:     KSPGetPCSide(ksp,&pcside);
5173:      if (pcside == PC_RIGHT || isNone) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
5174:       /* KSP residual is true linear residual */
5175:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
5176:     } else {
5177:       /* KSP residual is preconditioned residual */
5178:       /* compute true linear residual norm */
5179:       VecDuplicate(b,&lres);
5180:       MatMult(snes->jacobian,x,lres);
5181:       VecAYPX(lres,-1.0,b);
5182:       VecNorm(lres,NORM_2,&kctx->lresid_last);
5183:       VecDestroy(&lres);
5184:     }
5185:   }
5186:   return(0);
5187: }

5189: /*@
5190:    SNESGetKSP - Returns the KSP context for a SNES solver.

5192:    Not Collective, but if SNES object is parallel, then KSP object is parallel

5194:    Input Parameter:
5195: .  snes - the SNES context

5197:    Output Parameter:
5198: .  ksp - the KSP context

5200:    Notes:
5201:    The user can then directly manipulate the KSP context to set various
5202:    options, etc.  Likewise, the user can then extract and manipulate the
5203:    PC contexts as well.

5205:    Level: beginner

5207: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
5208: @*/
5209: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
5210: {


5217:   if (!snes->ksp) {
5218:     PetscBool monitor = PETSC_FALSE;

5220:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
5221:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
5222:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

5224:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
5225:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);

5227:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes",&monitor,NULL);
5228:     if (monitor) {
5229:       KSPMonitorSet(snes->ksp,KSPMonitorSNES,snes,NULL);
5230:     }
5231:     monitor = PETSC_FALSE;
5232:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes_lg",&monitor,NULL);
5233:     if (monitor) {
5234:       PetscObject *objs;
5235:       KSPMonitorSNESLGResidualNormCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,600,600,&objs);
5236:       objs[0] = (PetscObject) snes;
5237:       KSPMonitorSet(snes->ksp,(PetscErrorCode (*)(KSP,PetscInt,PetscReal,void*))KSPMonitorSNESLGResidualNorm,objs,(PetscErrorCode (*)(void**))KSPMonitorSNESLGResidualNormDestroy);
5238:     }
5239:     PetscObjectSetOptions((PetscObject)snes->ksp,((PetscObject)snes)->options);
5240:   }
5241:   *ksp = snes->ksp;
5242:   return(0);
5243: }


5246:  #include <petsc/private/dmimpl.h>
5247: /*@
5248:    SNESSetDM - Sets the DM that may be used by some nonlinear solvers or their underlying preconditioners

5250:    Logically Collective on SNES

5252:    Input Parameters:
5253: +  snes - the nonlinear solver context
5254: -  dm - the dm, cannot be NULL

5256:    Notes:
5257:    A DM can only be used for solving one problem at a time because information about the problem is stored on the DM,
5258:    even when not using interfaces like DMSNESSetFunction().  Use DMClone() to get a distinct DM when solving different
5259:    problems using the same function space.

5261:    Level: intermediate

5263: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
5264: @*/
5265: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
5266: {
5268:   KSP            ksp;
5269:   DMSNES         sdm;

5274:   PetscObjectReference((PetscObject)dm);
5275:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
5276:     if (snes->dm->dmsnes && !dm->dmsnes) {
5277:       DMCopyDMSNES(snes->dm,dm);
5278:       DMGetDMSNES(snes->dm,&sdm);
5279:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5280:     }
5281:     DMCoarsenHookRemove(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
5282:     DMDestroy(&snes->dm);
5283:   }
5284:   snes->dm     = dm;
5285:   snes->dmAuto = PETSC_FALSE;

5287:   SNESGetKSP(snes,&ksp);
5288:   KSPSetDM(ksp,dm);
5289:   KSPSetDMActive(ksp,PETSC_FALSE);
5290:   if (snes->npc) {
5291:     SNESSetDM(snes->npc, snes->dm);
5292:     SNESSetNPCSide(snes,snes->npcside);
5293:   }
5294:   return(0);
5295: }

5297: /*@
5298:    SNESGetDM - Gets the DM that may be used by some preconditioners

5300:    Not Collective but DM obtained is parallel on SNES

5302:    Input Parameter:
5303: . snes - the preconditioner context

5305:    Output Parameter:
5306: .  dm - the dm

5308:    Level: intermediate

5310: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
5311: @*/
5312: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
5313: {

5318:   if (!snes->dm) {
5319:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
5320:     snes->dmAuto = PETSC_TRUE;
5321:   }
5322:   *dm = snes->dm;
5323:   return(0);
5324: }

5326: /*@
5327:   SNESSetNPC - Sets the nonlinear preconditioner to be used.

5329:   Collective on SNES

5331:   Input Parameters:
5332: + snes - iterative context obtained from SNESCreate()
5333: - pc   - the preconditioner object

5335:   Notes:
5336:   Use SNESGetNPC() to retrieve the preconditioner context (for example,
5337:   to configure it using the API).

5339:   Level: developer

5341: .seealso: SNESGetNPC(), SNESHasNPC()
5342: @*/
5343: PetscErrorCode SNESSetNPC(SNES snes, SNES pc)
5344: {

5351:   PetscObjectReference((PetscObject) pc);
5352:   SNESDestroy(&snes->npc);
5353:   snes->npc = pc;
5354:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->npc);
5355:   return(0);
5356: }

5358: /*@
5359:   SNESGetNPC - Creates a nonlinear preconditioning solver (SNES) to be used to precondition the nonlinear solver.

5361:   Not Collective; but any changes to the obtained SNES object must be applied collectively

5363:   Input Parameter:
5364: . snes - iterative context obtained from SNESCreate()

5366:   Output Parameter:
5367: . pc - preconditioner context

5369:   Options Database:
5370: . -npc_snes_type <type> - set the type of the SNES to use as the nonlinear preconditioner

5372:   Notes:
5373:     If a SNES was previously set with SNESSetNPC() then that SNES is returned, otherwise a new SNES object is created.

5375:     The (preconditioner) SNES returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5376:     SNES during SNESSetUp()

5378:   Level: developer

5380: .seealso: SNESSetNPC(), SNESHasNPC(), SNES, SNESCreate()
5381: @*/
5382: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5383: {
5385:   const char     *optionsprefix;

5390:   if (!snes->npc) {
5391:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->npc);
5392:     PetscObjectIncrementTabLevel((PetscObject)snes->npc,(PetscObject)snes,1);
5393:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->npc);
5394:     SNESGetOptionsPrefix(snes,&optionsprefix);
5395:     SNESSetOptionsPrefix(snes->npc,optionsprefix);
5396:     SNESAppendOptionsPrefix(snes->npc,"npc_");
5397:     SNESSetCountersReset(snes->npc,PETSC_FALSE);
5398:   }
5399:   *pc = snes->npc;
5400:   return(0);
5401: }

5403: /*@
5404:   SNESHasNPC - Returns whether a nonlinear preconditioner exists

5406:   Not Collective

5408:   Input Parameter:
5409: . snes - iterative context obtained from SNESCreate()

5411:   Output Parameter:
5412: . has_npc - whether the SNES has an NPC or not

5414:   Level: developer

5416: .seealso: SNESSetNPC(), SNESGetNPC()
5417: @*/
5418: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5419: {
5422:   *has_npc = (PetscBool) (snes->npc ? PETSC_TRUE : PETSC_FALSE);
5423:   return(0);
5424: }

5426: /*@
5427:     SNESSetNPCSide - Sets the preconditioning side.

5429:     Logically Collective on SNES

5431:     Input Parameter:
5432: .   snes - iterative context obtained from SNESCreate()

5434:     Output Parameter:
5435: .   side - the preconditioning side, where side is one of
5436: .vb
5437:       PC_LEFT - left preconditioning
5438:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5439: .ve

5441:     Options Database Keys:
5442: .   -snes_pc_side <right,left>

5444:     Notes:
5445:     SNESNRICHARDSON and SNESNCG only support left preconditioning.

5447:     Level: intermediate

5449: .seealso: SNESGetNPCSide(), KSPSetPCSide()
5450: @*/
5451: PetscErrorCode  SNESSetNPCSide(SNES snes,PCSide side)
5452: {
5456:   snes->npcside= side;
5457:   return(0);
5458: }

5460: /*@
5461:     SNESGetNPCSide - Gets the preconditioning side.

5463:     Not Collective

5465:     Input Parameter:
5466: .   snes - iterative context obtained from SNESCreate()

5468:     Output Parameter:
5469: .   side - the preconditioning side, where side is one of
5470: .vb
5471:       PC_LEFT - left preconditioning
5472:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5473: .ve

5475:     Level: intermediate

5477: .seealso: SNESSetNPCSide(), KSPGetPCSide()
5478: @*/
5479: PetscErrorCode  SNESGetNPCSide(SNES snes,PCSide *side)
5480: {
5484:   *side = snes->npcside;
5485:   return(0);
5486: }

5488: /*@
5489:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

5491:   Collective on SNES

5493:   Input Parameters:
5494: + snes - iterative context obtained from SNESCreate()
5495: - linesearch   - the linesearch object

5497:   Notes:
5498:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
5499:   to configure it using the API).

5501:   Level: developer

5503: .seealso: SNESGetLineSearch()
5504: @*/
5505: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5506: {

5513:   PetscObjectReference((PetscObject) linesearch);
5514:   SNESLineSearchDestroy(&snes->linesearch);

5516:   snes->linesearch = linesearch;

5518:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5519:   return(0);
5520: }

5522: /*@
5523:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
5524:   or creates a default line search instance associated with the SNES and returns it.

5526:   Not Collective

5528:   Input Parameter:
5529: . snes - iterative context obtained from SNESCreate()

5531:   Output Parameter:
5532: . linesearch - linesearch context

5534:   Level: beginner

5536: .seealso: SNESSetLineSearch(), SNESLineSearchCreate()
5537: @*/
5538: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5539: {
5541:   const char     *optionsprefix;

5546:   if (!snes->linesearch) {
5547:     SNESGetOptionsPrefix(snes, &optionsprefix);
5548:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
5549:     SNESLineSearchSetSNES(snes->linesearch, snes);
5550:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
5551:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
5552:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5553:   }
5554:   *linesearch = snes->linesearch;
5555:   return(0);
5556: }