Actual source code: snes.c

petsc-master 2019-06-26
Report Typos and Errors
  1:  #include <petsc/private/snesimpl.h>
  2:  #include <petscdmshell.h>
  3:  #include <petscdraw.h>
  4:  #include <petscds.h>
  5:  #include <petscdmadaptor.h>
  6:  #include <petscconvest.h>

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

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

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

 18:    Logically Collective on SNES

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

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

 27:    Level: intermediate

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

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

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

 47:    Not Collective

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

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

 55:    Level: intermediate

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

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

 71:    Logically Collective on SNES

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

 77:    Level: advanced

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

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

 92:    Logically Collective on SNES

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

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

100:    Level: advanced

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

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

116:    Logically Collective on SNES

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

121:    Level: advanced

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

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

137:    Logically Collective on SNES

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

142:    Level: advanced

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

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

159:    Logically Collective on SNES

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

165:    Level: advanced

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

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

180:    Logically Collective on SNES

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

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

188:    Level: advanced

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

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

204:    Logically Collective on SNES

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

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

212:    Level: advanced

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

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

228:    Logically Collective on SNES

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

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

236:    Level: advanced

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

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

252:   Collective on PetscViewer

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

259:    Level: intermediate

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

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

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

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

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

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

311: /*@C
312:    SNESView - Prints the SNES data structure.

314:    Collective on SNES

316:    Input Parameters:
317: +  SNES - the SNES context
318: -  viewer - visualization context

320:    Options Database Key:
321: .  -snes_view - Calls SNESView() at end of SNESSolve()

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

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

334:    Level: beginner

336: .seealso: PetscViewerASCIIOpen()
337: @*/
338: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
339: {
340:   SNESKSPEW      *kctx;
342:   KSP            ksp;
343:   SNESLineSearch linesearch;
344:   PetscBool      iascii,isstring,isbinary,isdraw;
345:   DMSNES         dmsnes;
346: #if defined(PETSC_HAVE_SAWS)
347:   PetscBool      issaws;
348: #endif

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

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

371:     PetscObjectPrintClassNamePrefixType((PetscObject)snes,viewer);
372:     if (!snes->setupcalled) {
373:       PetscViewerASCIIPrintf(viewer,"  SNES has not been set up so information may be incomplete\n");
374:     }
375:     if (snes->ops->view) {
376:       PetscViewerASCIIPushTab(viewer);
377:       (*snes->ops->view)(snes,viewer);
378:       PetscViewerASCIIPopTab(viewer);
379:     }
380:     PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
381:     PetscViewerASCIIPrintf(viewer,"  tolerances: relative=%g, absolute=%g, solution=%g\n",(double)snes->rtol,(double)snes->abstol,(double)snes->stol);
382:     if (snes->usesksp) {
383:       PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",snes->linear_its);
384:     }
385:     PetscViewerASCIIPrintf(viewer,"  total number of function evaluations=%D\n",snes->nfuncs);
386:     SNESGetNormSchedule(snes, &normschedule);
387:     if (normschedule > 0) {PetscViewerASCIIPrintf(viewer,"  norm schedule %s\n",SNESNormSchedules[normschedule]);}
388:     if (snes->gridsequence) {
389:       PetscViewerASCIIPrintf(viewer,"  total number of grid sequence refinements=%D\n",snes->gridsequence);
390:     }
391:     if (snes->ksp_ewconv) {
392:       kctx = (SNESKSPEW*)snes->kspconvctx;
393:       if (kctx) {
394:         PetscViewerASCIIPrintf(viewer,"  Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
395:         PetscViewerASCIIPrintf(viewer,"    rtol_0=%g, rtol_max=%g, threshold=%g\n",(double)kctx->rtol_0,(double)kctx->rtol_max,(double)kctx->threshold);
396:         PetscViewerASCIIPrintf(viewer,"    gamma=%g, alpha=%g, alpha2=%g\n",(double)kctx->gamma,(double)kctx->alpha,(double)kctx->alpha2);
397:       }
398:     }
399:     if (snes->lagpreconditioner == -1) {
400:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is never rebuilt\n");
401:     } else if (snes->lagpreconditioner > 1) {
402:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is rebuilt every %D new Jacobians\n",snes->lagpreconditioner);
403:     }
404:     if (snes->lagjacobian == -1) {
405:       PetscViewerASCIIPrintf(viewer,"  Jacobian is never rebuilt\n");
406:     } else if (snes->lagjacobian > 1) {
407:       PetscViewerASCIIPrintf(viewer,"  Jacobian is rebuilt every %D SNES iterations\n",snes->lagjacobian);
408:     }
409:     SNESGetDM(snes,&dm);
410:     DMSNESGetJacobian(dm,&cJ,&ctx);
411:     if (cJ == SNESComputeJacobianDefault) {
412:       PetscViewerASCIIPrintf(viewer,"  Jacobian is built using finite differences one column at a time\n");
413:     } else if (cJ == SNESComputeJacobianDefaultColor) {
414:       PetscViewerASCIIPrintf(viewer,"  Jacobian is built using finite differences with coloring\n");
415:     }
416:   } else if (isstring) {
417:     const char *type;
418:     SNESGetType(snes,&type);
419:     PetscViewerStringSPrintf(viewer," SNESType: %-7.7s",type);
420:     if (snes->ops->view) {(*snes->ops->view)(snes,viewer);}
421:   } else if (isbinary) {
422:     PetscInt    classid = SNES_FILE_CLASSID;
423:     MPI_Comm    comm;
424:     PetscMPIInt rank;
425:     char        type[256];

427:     PetscObjectGetComm((PetscObject)snes,&comm);
428:     MPI_Comm_rank(comm,&rank);
429:     if (!rank) {
430:       PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);
431:       PetscStrncpy(type,((PetscObject)snes)->type_name,sizeof(type));
432:       PetscViewerBinaryWrite(viewer,type,sizeof(type),PETSC_CHAR,PETSC_FALSE);
433:     }
434:     if (snes->ops->view) {
435:       (*snes->ops->view)(snes,viewer);
436:     }
437:   } else if (isdraw) {
438:     PetscDraw draw;
439:     char      str[36];
440:     PetscReal x,y,bottom,h;

442:     PetscViewerDrawGetDraw(viewer,0,&draw);
443:     PetscDrawGetCurrentPoint(draw,&x,&y);
444:     PetscStrncpy(str,"SNES: ",sizeof(str));
445:     PetscStrlcat(str,((PetscObject)snes)->type_name,sizeof(str));
446:     PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_BLUE,PETSC_DRAW_BLACK,str,NULL,&h);
447:     bottom = y - h;
448:     PetscDrawPushCurrentPoint(draw,x,bottom);
449:     if (snes->ops->view) {
450:       (*snes->ops->view)(snes,viewer);
451:     }
452: #if defined(PETSC_HAVE_SAWS)
453:   } else if (issaws) {
454:     PetscMPIInt rank;
455:     const char *name;

457:     PetscObjectGetName((PetscObject)snes,&name);
458:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
459:     if (!((PetscObject)snes)->amsmem && !rank) {
460:       char       dir[1024];

462:       PetscObjectViewSAWs((PetscObject)snes,viewer);
463:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
464:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
465:       if (!snes->conv_hist) {
466:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
467:       }
468:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
469:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
470:     }
471: #endif
472:   }
473:   if (snes->linesearch) {
474:     SNESGetLineSearch(snes, &linesearch);
475:     PetscViewerASCIIPushTab(viewer);
476:     SNESLineSearchView(linesearch, viewer);
477:     PetscViewerASCIIPopTab(viewer);
478:   }
479:   if (snes->npc && snes->usesnpc) {
480:     PetscViewerASCIIPushTab(viewer);
481:     SNESView(snes->npc, viewer);
482:     PetscViewerASCIIPopTab(viewer);
483:   }
484:   PetscViewerASCIIPushTab(viewer);
485:   DMGetDMSNES(snes->dm,&dmsnes);
486:   DMSNESView(dmsnes, viewer);
487:   PetscViewerASCIIPopTab(viewer);
488:   if (snes->usesksp) {
489:     SNESGetKSP(snes,&ksp);
490:     PetscViewerASCIIPushTab(viewer);
491:     KSPView(ksp,viewer);
492:     PetscViewerASCIIPopTab(viewer);
493:   }
494:   if (isdraw) {
495:     PetscDraw draw;
496:     PetscViewerDrawGetDraw(viewer,0,&draw);
497:     PetscDrawPopCurrentPoint(draw);
498:   }
499:   return(0);
500: }

502: /*
503:   We retain a list of functions that also take SNES command
504:   line options. These are called at the end SNESSetFromOptions()
505: */
506: #define MAXSETFROMOPTIONS 5
507: static PetscInt numberofsetfromoptions;
508: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

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

513:   Not Collective

515:   Input Parameter:
516: . snescheck - function that checks for options

518:   Level: developer

520: .seealso: SNESSetFromOptions()
521: @*/
522: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
523: {
525:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
526:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
527:   return(0);
528: }

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

532: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
533: {
534:   Mat            J;
535:   KSP            ksp;
536:   PC             pc;
537:   PetscBool      match;
539:   MatNullSpace   nullsp;


544:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
545:     Mat A = snes->jacobian, B = snes->jacobian_pre;
546:     MatCreateVecs(A ? A : B, NULL,&snes->vec_func);
547:   }

549:   if (version == 1) {
550:     MatCreateSNESMF(snes,&J);
551:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
552:     MatSetFromOptions(J);
553:   } else if (version == 2) {
554:     if (!snes->vec_func) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first");
555: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
556:     SNESDefaultMatrixFreeCreate2(snes,snes->vec_func,&J);
557: #else
558:     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP, "matrix-free operator rutines (version 2)");
559: #endif
560:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator rutines, only version 1 and 2");

562:   /* attach any user provided null space that was on Amat to the newly created matrix free matrix */
563:   if (snes->jacobian) {
564:     MatGetNullSpace(snes->jacobian,&nullsp);
565:     if (nullsp) {
566:       MatSetNullSpace(J,nullsp);
567:     }
568:   }

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

573:     /* This version replaces the user provided Jacobian matrix with a
574:        matrix-free version but still employs the user-provided preconditioner matrix. */
575:     SNESSetJacobian(snes,J,0,0,0);
576:   } else {
577:     /* This version replaces both the user-provided Jacobian and the user-
578:      provided preconditioner Jacobian with the default matrix free version. */
579:     if ((snes->npcside== PC_LEFT) && snes->npc) {
580:       if (!snes->jacobian){SNESSetJacobian(snes,J,0,0,0);}
581:     } else {
582:       SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,0);
583:     }
584:     /* Force no preconditioner */
585:     SNESGetKSP(snes,&ksp);
586:     KSPGetPC(ksp,&pc);
587:     PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&match);
588:     if (!match) {
589:       PetscInfo(snes,"Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n");
590:       PCSetType(pc,PCNONE);
591:     }
592:   }
593:   MatDestroy(&J);
594:   return(0);
595: }

597: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
598: {
599:   SNES           snes = (SNES)ctx;
601:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

604:   if (PetscLogPrintInfo) {
605:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
606:     DMGetRefineLevel(dmfine,&finelevel);
607:     DMGetCoarsenLevel(dmfine,&fineclevel);
608:     DMGetRefineLevel(dmcoarse,&coarselevel);
609:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
610:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
611:   }
612:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
613:   else {
614:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
615:     Xfine = Xfine_named;
616:   }
617:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
618:   if (Inject) {
619:     MatRestrict(Inject,Xfine,Xcoarse);
620:   } else {
621:     MatRestrict(Restrict,Xfine,Xcoarse);
622:     VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
623:   }
624:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
625:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
626:   return(0);
627: }

629: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
630: {

634:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
635:   return(0);
636: }

638: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
639:  * safely call SNESGetDM() in their residual evaluation routine. */
640: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,void *ctx)
641: {
642:   SNES           snes = (SNES)ctx;
644:   Vec            X,Xnamed = NULL;
645:   DM             dmsave;
646:   void           *ctxsave;
647:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*) = NULL;

650:   dmsave = snes->dm;
651:   KSPGetDM(ksp,&snes->dm);
652:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
653:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
654:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
655:     X    = Xnamed;
656:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
657:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
658:     if (jac == SNESComputeJacobianDefaultColor) {
659:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,0);
660:     }
661:   }
662:   /* Make sure KSP DM has the Jacobian computation routine */
663:   {
664:     DMSNES sdm;

666:     DMGetDMSNES(snes->dm, &sdm);
667:     if (!sdm->ops->computejacobian) {
668:       DMCopyDMSNES(dmsave, snes->dm);
669:     }
670:   }
671:   /* Compute the operators */
672:   SNESComputeJacobian(snes,X,A,B);
673:   /* Put the previous context back */
674:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
675:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
676:   }

678:   if (Xnamed) {DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);}
679:   snes->dm = dmsave;
680:   return(0);
681: }

683: /*@
684:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

686:    Collective

688:    Input Arguments:
689: .  snes - snes to configure

691:    Level: developer

693: .seealso: SNESSetUp()
694: @*/
695: PetscErrorCode SNESSetUpMatrices(SNES snes)
696: {
698:   DM             dm;
699:   DMSNES         sdm;

702:   SNESGetDM(snes,&dm);
703:   DMGetDMSNES(dm,&sdm);
704:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_PLIB,"DMSNES not properly configured");
705:   else if (!snes->jacobian && snes->mf) {
706:     Mat  J;
707:     void *functx;
708:     MatCreateSNESMF(snes,&J);
709:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
710:     MatSetFromOptions(J);
711:     SNESGetFunction(snes,NULL,NULL,&functx);
712:     SNESSetJacobian(snes,J,J,0,0);
713:     MatDestroy(&J);
714:   } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
715:     Mat J,B;
716:     MatCreateSNESMF(snes,&J);
717:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
718:     MatSetFromOptions(J);
719:     DMCreateMatrix(snes->dm,&B);
720:     /* sdm->computejacobian was already set to reach here */
721:     SNESSetJacobian(snes,J,B,NULL,NULL);
722:     MatDestroy(&J);
723:     MatDestroy(&B);
724:   } else if (!snes->jacobian_pre) {
725:     PetscErrorCode (*nspconstr)(DM, PetscInt, MatNullSpace *);
726:     PetscDS          prob;
727:     Mat              J, B;
728:     MatNullSpace     nullspace = NULL;
729:     PetscBool        hasPrec   = PETSC_FALSE;
730:     PetscInt         Nf;

732:     J    = snes->jacobian;
733:     DMGetDS(dm, &prob);
734:     if (prob) {PetscDSHasJacobianPreconditioner(prob, &hasPrec);}
735:     if (J)            {PetscObjectReference((PetscObject) J);}
736:     else if (hasPrec) {DMCreateMatrix(snes->dm, &J);}
737:     DMCreateMatrix(snes->dm, &B);
738:     PetscDSGetNumFields(prob, &Nf);
739:     DMGetNullSpaceConstructor(snes->dm, Nf, &nspconstr);
740:     if (nspconstr) (*nspconstr)(snes->dm, -1, &nullspace);
741:     MatSetNullSpace(B, nullspace);
742:     MatNullSpaceDestroy(&nullspace);
743:     SNESSetJacobian(snes, J ? J : B, B, NULL, NULL);
744:     MatDestroy(&J);
745:     MatDestroy(&B);
746:   }
747:   {
748:     KSP ksp;
749:     SNESGetKSP(snes,&ksp);
750:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
751:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
752:   }
753:   return(0);
754: }

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

759:    Collective on SNES

761:    Input Parameters:
762: +  snes - SNES object you wish to monitor
763: .  name - the monitor type one is seeking
764: .  help - message indicating what monitoring is done
765: .  manual - manual page for the monitor
766: .  monitor - the monitor function
767: -  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

769:    Level: developer

771: .seealso: PetscOptionsGetViewer(), PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(),
772:           PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool()
773:           PetscOptionsInt(), PetscOptionsString(), PetscOptionsReal(), PetscOptionsBool(),
774:           PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(),
775:           PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(),
776:           PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(),
777:           PetscOptionsFList(), PetscOptionsEList()
778: @*/
779: PetscErrorCode  SNESMonitorSetFromOptions(SNES snes,const char name[],const char help[], const char manual[],PetscErrorCode (*monitor)(SNES,PetscInt,PetscReal,PetscViewerAndFormat*),PetscErrorCode (*monitorsetup)(SNES,PetscViewerAndFormat*))
780: {
781:   PetscErrorCode    ierr;
782:   PetscViewer       viewer;
783:   PetscViewerFormat format;
784:   PetscBool         flg;

787:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,name,&viewer,&format,&flg);
788:   if (flg) {
789:     PetscViewerAndFormat *vf;
790:     PetscViewerAndFormatCreate(viewer,format,&vf);
791:     PetscObjectDereference((PetscObject)viewer);
792:     if (monitorsetup) {
793:       (*monitorsetup)(snes,vf);
794:     }
795:     SNESMonitorSet(snes,(PetscErrorCode (*)(SNES,PetscInt,PetscReal,void*))monitor,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);
796:   }
797:   return(0);
798: }

800: /*@
801:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

803:    Collective on SNES

805:    Input Parameter:
806: .  snes - the SNES context

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

838:     Options Database for Eisenstat-Walker method:
839: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
840: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
841: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
842: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
843: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
844: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
845: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
846: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

848:    Notes:
849:    To see all options, run your program with the -help option or consult
850:    Users-Manual: ch_snes

852:    Level: beginner

854: .seealso: SNESSetOptionsPrefix(), SNESResetFromOptions()
855: @*/
856: PetscErrorCode  SNESSetFromOptions(SNES snes)
857: {
858:   PetscBool      flg,pcset,persist,set;
859:   PetscInt       i,indx,lag,grids;
860:   const char     *deft        = SNESNEWTONLS;
861:   const char     *convtests[] = {"default","skip"};
862:   SNESKSPEW      *kctx        = NULL;
863:   char           type[256], monfilename[PETSC_MAX_PATH_LEN];
865:   PCSide         pcside;
866:   const char     *optionsprefix;

870:   SNESRegisterAll();
871:   PetscObjectOptionsBegin((PetscObject)snes);
872:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
873:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
874:   if (flg) {
875:     SNESSetType(snes,type);
876:   } else if (!((PetscObject)snes)->type_name) {
877:     SNESSetType(snes,deft);
878:   }
879:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,NULL);
880:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,NULL);

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

892:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
893:   if (flg) {
894:     SNESSetLagPreconditioner(snes,lag);
895:   }
896:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
897:   if (flg) {
898:     SNESSetLagPreconditionerPersists(snes,persist);
899:   }
900:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
901:   if (flg) {
902:     SNESSetLagJacobian(snes,lag);
903:   }
904:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
905:   if (flg) {
906:     SNESSetLagJacobianPersists(snes,persist);
907:   }

909:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
910:   if (flg) {
911:     SNESSetGridSequence(snes,grids);
912:   }

914:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,2,"default",&indx,&flg);
915:   if (flg) {
916:     switch (indx) {
917:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
918:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL);    break;
919:     }
920:   }

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

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

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

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

932:   PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,NULL);
933:   PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,NULL);
934:   PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,NULL);
935:   PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,NULL);
936:   PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,NULL);
937:   PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,NULL);
938:   PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",kctx->threshold,&kctx->threshold,NULL);

940:   flg  = PETSC_FALSE;
941:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,&set);
942:   if (set && flg) {SNESMonitorCancel(snes);}

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

948:   SNESMonitorSetFromOptions(snes,"-snes_monitor_ratio","Monitor ratios of the norm of function for consecutive steps","SNESMonitorRatio",SNESMonitorRatio,SNESMonitorRatioSetUp);
949:   SNESMonitorSetFromOptions(snes,"-snes_monitor_field","Monitor norm of function (split into fields)","SNESMonitorDefaultField",SNESMonitorDefaultField,NULL);
950:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution","View solution at each iteration","SNESMonitorSolution",SNESMonitorSolution,NULL);
951:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution_update","View correction at each iteration","SNESMonitorSolutionUpdate",SNESMonitorSolutionUpdate,NULL);
952:   SNESMonitorSetFromOptions(snes,"-snes_monitor_residual","View residual at each iteration","SNESMonitorResidual",SNESMonitorResidual,NULL);
953:   SNESMonitorSetFromOptions(snes,"-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",SNESMonitorJacUpdateSpectrum,NULL);
954:   SNESMonitorSetFromOptions(snes,"-snes_monitor_fields","Monitor norm of function per field","SNESMonitorSet",SNESMonitorFields,NULL);

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


960:   flg  = PETSC_FALSE;
961:   PetscOptionsBool("-snes_monitor_lg_residualnorm","Plot function norm at each iteration","SNESMonitorLGResidualNorm",flg,&flg,NULL);
962:   if (flg) {
963:     PetscDrawLG ctx;

965:     SNESMonitorLGCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
966:     SNESMonitorSet(snes,SNESMonitorLGResidualNorm,ctx,(PetscErrorCode (*)(void**))PetscDrawLGDestroy);
967:   }
968:   flg  = PETSC_FALSE;
969:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
970:   if (flg) {
971:     PetscViewer ctx;

973:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
974:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
975:   }



979:   flg  = PETSC_FALSE;
980:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
981:   if (flg) {
982:     void    *functx;
983:     DM      dm;
984:     DMSNES  sdm;
985:     SNESGetDM(snes,&dm);
986:     DMGetDMSNES(dm,&sdm);
987:     sdm->jacobianctx = NULL;
988:     SNESGetFunction(snes,NULL,NULL,&functx);
989:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
990:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
991:   }

993:   flg  = PETSC_FALSE;
994:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
995:   if (flg) {
996:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
997:   }

999:   flg  = PETSC_FALSE;
1000:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
1001:   if (flg) {
1002:     DM             dm;
1003:     DMSNES         sdm;
1004:     SNESGetDM(snes,&dm);
1005:     DMGetDMSNES(dm,&sdm);
1006:     sdm->jacobianctx = NULL;
1007:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,0);
1008:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
1009:   }

1011:   flg  = PETSC_FALSE;
1012:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf_operator,&flg);
1013:   if (flg && snes->mf_operator) {
1014:     snes->mf_operator = PETSC_TRUE;
1015:     snes->mf          = PETSC_TRUE;
1016:   }
1017:   flg  = PETSC_FALSE;
1018:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf,&flg);
1019:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
1020:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,0);

1022:   flg  = PETSC_FALSE;
1023:   SNESGetNPCSide(snes,&pcside);
1024:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetNPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
1025:   if (flg) {SNESSetNPCSide(snes,pcside);}

1027: #if defined(PETSC_HAVE_SAWS)
1028:   /*
1029:     Publish convergence information using SAWs
1030:   */
1031:   flg  = PETSC_FALSE;
1032:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
1033:   if (flg) {
1034:     void *ctx;
1035:     SNESMonitorSAWsCreate(snes,&ctx);
1036:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
1037:   }
1038: #endif
1039: #if defined(PETSC_HAVE_SAWS)
1040:   {
1041:   PetscBool set;
1042:   flg  = PETSC_FALSE;
1043:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
1044:   if (set) {
1045:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
1046:   }
1047:   }
1048: #endif

1050:   for (i = 0; i < numberofsetfromoptions; i++) {
1051:     (*othersetfromoptions[i])(snes);
1052:   }

1054:   if (snes->ops->setfromoptions) {
1055:     (*snes->ops->setfromoptions)(PetscOptionsObject,snes);
1056:   }

1058:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
1059:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)snes);
1060:   PetscOptionsEnd();

1062:   if (snes->linesearch) {
1063:     SNESGetLineSearch(snes, &snes->linesearch);
1064:     SNESLineSearchSetFromOptions(snes->linesearch);
1065:   }

1067:   if (snes->usesksp) {
1068:     if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
1069:     KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
1070:     KSPSetFromOptions(snes->ksp);
1071:   }

1073:   /* if someone has set the SNES NPC type, create it. */
1074:   SNESGetOptionsPrefix(snes, &optionsprefix);
1075:   PetscOptionsHasName(((PetscObject)snes)->options,optionsprefix, "-npc_snes_type", &pcset);
1076:   if (pcset && (!snes->npc)) {
1077:     SNESGetNPC(snes, &snes->npc);
1078:   }
1079:   snes->setfromoptionscalled++;
1080:   return(0);
1081: }

1083: /*@
1084:    SNESResetFromOptions - Sets various SNES and KSP parameters from user options ONLY if the SNES was previously set from options

1086:    Collective on SNES

1088:    Input Parameter:
1089: .  snes - the SNES context

1091:    Level: beginner

1093: .seealso: SNESSetFromOptions(), SNESSetOptionsPrefix()
1094: @*/
1095: PetscErrorCode SNESResetFromOptions(SNES snes)
1096: {

1100:   if (snes->setfromoptionscalled) {SNESSetFromOptions(snes);}
1101:   return(0);
1102: }

1104: /*@C
1105:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
1106:    the nonlinear solvers.

1108:    Logically Collective on SNES

1110:    Input Parameters:
1111: +  snes - the SNES context
1112: .  compute - function to compute the context
1113: -  destroy - function to destroy the context

1115:    Level: intermediate

1117:    Notes:
1118:    This function is currently not available from Fortran.

1120: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
1121: @*/
1122: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
1123: {
1126:   snes->ops->usercompute = compute;
1127:   snes->ops->userdestroy = destroy;
1128:   return(0);
1129: }

1131: /*@
1132:    SNESSetApplicationContext - Sets the optional user-defined context for
1133:    the nonlinear solvers.

1135:    Logically Collective on SNES

1137:    Input Parameters:
1138: +  snes - the SNES context
1139: -  usrP - optional user context

1141:    Level: intermediate

1143:    Fortran Notes:
1144:     To use this from Fortran you must write a Fortran interface definition for this
1145:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1147: .seealso: SNESGetApplicationContext()
1148: @*/
1149: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
1150: {
1152:   KSP            ksp;

1156:   SNESGetKSP(snes,&ksp);
1157:   KSPSetApplicationContext(ksp,usrP);
1158:   snes->user = usrP;
1159:   return(0);
1160: }

1162: /*@
1163:    SNESGetApplicationContext - Gets the user-defined context for the
1164:    nonlinear solvers.

1166:    Not Collective

1168:    Input Parameter:
1169: .  snes - SNES context

1171:    Output Parameter:
1172: .  usrP - user context

1174:    Fortran Notes:
1175:     To use this from Fortran you must write a Fortran interface definition for this
1176:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1178:    Level: intermediate

1180: .seealso: SNESSetApplicationContext()
1181: @*/
1182: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
1183: {
1186:   *(void**)usrP = snes->user;
1187:   return(0);
1188: }

1190: /*@
1191:    SNESSetUseMatrixFree - indicates that SNES should use matrix free finite difference matrix vector products internally to apply
1192:                           the Jacobian.

1194:    Collective on SNES

1196:    Input Parameters:
1197: +  snes - SNES context
1198: .  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored
1199: -  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used

1201:    Options Database:
1202: + -snes_mf - use matrix free for both the mat and pmat operator
1203: - -snes_mf_operator - use matrix free only for the mat operator

1205:    Level: intermediate

1207: .seealso:   SNESGetUseMatrixFree(), MatCreateSNESMF()
1208: @*/
1209: PetscErrorCode  SNESSetUseMatrixFree(SNES snes,PetscBool mf_operator,PetscBool mf)
1210: {
1215:   if (mf && !mf_operator) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"If using mf must also use mf_operator");
1216:   snes->mf          = mf;
1217:   snes->mf_operator = mf_operator;
1218:   return(0);
1219: }

1221: /*@
1222:    SNESGetUseMatrixFree - indicates if the SNES uses matrix free finite difference matrix vector products to apply
1223:                           the Jacobian.

1225:    Collective on SNES

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

1230:    Output Parameters:
1231: +  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored
1232: -  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used

1234:    Options Database:
1235: + -snes_mf - use matrix free for both the mat and pmat operator
1236: - -snes_mf_operator - use matrix free only for the mat operator

1238:    Level: intermediate

1240: .seealso:   SNESSetUseMatrixFree(), MatCreateSNESMF()
1241: @*/
1242: PetscErrorCode  SNESGetUseMatrixFree(SNES snes,PetscBool *mf_operator,PetscBool *mf)
1243: {
1246:   if (mf)          *mf          = snes->mf;
1247:   if (mf_operator) *mf_operator = snes->mf_operator;
1248:   return(0);
1249: }

1251: /*@
1252:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1253:    at this time.

1255:    Not Collective

1257:    Input Parameter:
1258: .  snes - SNES context

1260:    Output Parameter:
1261: .  iter - iteration number

1263:    Notes:
1264:    For example, during the computation of iteration 2 this would return 1.

1266:    This is useful for using lagged Jacobians (where one does not recompute the
1267:    Jacobian at each SNES iteration). For example, the code
1268: .vb
1269:       SNESGetIterationNumber(snes,&it);
1270:       if (!(it % 2)) {
1271:         [compute Jacobian here]
1272:       }
1273: .ve
1274:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1275:    recomputed every second SNES iteration.

1277:    After the SNES solve is complete this will return the number of nonlinear iterations used.

1279:    Level: intermediate

1281: .seealso:   SNESGetLinearSolveIterations()
1282: @*/
1283: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1284: {
1288:   *iter = snes->iter;
1289:   return(0);
1290: }

1292: /*@
1293:    SNESSetIterationNumber - Sets the current iteration number.

1295:    Not Collective

1297:    Input Parameter:
1298: .  snes - SNES context
1299: .  iter - iteration number

1301:    Level: developer

1303: .seealso:   SNESGetLinearSolveIterations()
1304: @*/
1305: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1306: {

1311:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1312:   snes->iter = iter;
1313:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1314:   return(0);
1315: }

1317: /*@
1318:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1319:    attempted by the nonlinear solver.

1321:    Not Collective

1323:    Input Parameter:
1324: .  snes - SNES context

1326:    Output Parameter:
1327: .  nfails - number of unsuccessful steps attempted

1329:    Notes:
1330:    This counter is reset to zero for each successive call to SNESSolve().

1332:    Level: intermediate

1334: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1335:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1336: @*/
1337: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1338: {
1342:   *nfails = snes->numFailures;
1343:   return(0);
1344: }

1346: /*@
1347:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1348:    attempted by the nonlinear solver before it gives up.

1350:    Not Collective

1352:    Input Parameters:
1353: +  snes     - SNES context
1354: -  maxFails - maximum of unsuccessful steps

1356:    Level: intermediate

1358: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1359:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1360: @*/
1361: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1362: {
1365:   snes->maxFailures = maxFails;
1366:   return(0);
1367: }

1369: /*@
1370:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1371:    attempted by the nonlinear solver before it gives up.

1373:    Not Collective

1375:    Input Parameter:
1376: .  snes     - SNES context

1378:    Output Parameter:
1379: .  maxFails - maximum of unsuccessful steps

1381:    Level: intermediate

1383: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1384:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1386: @*/
1387: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1388: {
1392:   *maxFails = snes->maxFailures;
1393:   return(0);
1394: }

1396: /*@
1397:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1398:      done by SNES.

1400:    Not Collective

1402:    Input Parameter:
1403: .  snes     - SNES context

1405:    Output Parameter:
1406: .  nfuncs - number of evaluations

1408:    Level: intermediate

1410:    Notes:
1411:     Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1413: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1414: @*/
1415: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1416: {
1420:   *nfuncs = snes->nfuncs;
1421:   return(0);
1422: }

1424: /*@
1425:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1426:    linear solvers.

1428:    Not Collective

1430:    Input Parameter:
1431: .  snes - SNES context

1433:    Output Parameter:
1434: .  nfails - number of failed solves

1436:    Level: intermediate

1438:    Options Database Keys:
1439: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1441:    Notes:
1442:    This counter is reset to zero for each successive call to SNESSolve().

1444: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1445: @*/
1446: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1447: {
1451:   *nfails = snes->numLinearSolveFailures;
1452:   return(0);
1453: }

1455: /*@
1456:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1457:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1459:    Logically Collective on SNES

1461:    Input Parameters:
1462: +  snes     - SNES context
1463: -  maxFails - maximum allowed linear solve failures

1465:    Level: intermediate

1467:    Options Database Keys:
1468: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1470:    Notes:
1471:     By default this is 0; that is SNES returns on the first failed linear solve

1473: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations()
1474: @*/
1475: PetscErrorCode  SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1476: {
1480:   snes->maxLinearSolveFailures = maxFails;
1481:   return(0);
1482: }

1484: /*@
1485:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1486:      are allowed before SNES terminates

1488:    Not Collective

1490:    Input Parameter:
1491: .  snes     - SNES context

1493:    Output Parameter:
1494: .  maxFails - maximum of unsuccessful solves allowed

1496:    Level: intermediate

1498:    Notes:
1499:     By default this is 1; that is SNES returns on the first failed linear solve

1501: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1502: @*/
1503: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1504: {
1508:   *maxFails = snes->maxLinearSolveFailures;
1509:   return(0);
1510: }

1512: /*@
1513:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1514:    used by the nonlinear solver.

1516:    Not Collective

1518:    Input Parameter:
1519: .  snes - SNES context

1521:    Output Parameter:
1522: .  lits - number of linear iterations

1524:    Notes:
1525:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1527:    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
1528:    then call KSPGetIterationNumber() after the failed solve.

1530:    Level: intermediate

1532: .seealso:  SNESGetIterationNumber(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1533: @*/
1534: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1535: {
1539:   *lits = snes->linear_its;
1540:   return(0);
1541: }

1543: /*@
1544:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1545:    are reset every time SNESSolve() is called.

1547:    Logically Collective on SNES

1549:    Input Parameter:
1550: +  snes - SNES context
1551: -  reset - whether to reset the counters or not

1553:    Notes:
1554:    This defaults to PETSC_TRUE

1556:    Level: developer

1558: .seealso:  SNESGetNumberFunctionEvals(), SNESGetLinearSolveIterations(), SNESGetNPC()
1559: @*/
1560: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1561: {
1565:   snes->counters_reset = reset;
1566:   return(0);
1567: }


1570: /*@
1571:    SNESSetKSP - Sets a KSP context for the SNES object to use

1573:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1575:    Input Parameters:
1576: +  snes - the SNES context
1577: -  ksp - the KSP context

1579:    Notes:
1580:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1581:    so this routine is rarely needed.

1583:    The KSP object that is already in the SNES object has its reference count
1584:    decreased by one.

1586:    Level: developer

1588: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1589: @*/
1590: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1591: {

1598:   PetscObjectReference((PetscObject)ksp);
1599:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1600:   snes->ksp = ksp;
1601:   return(0);
1602: }

1604: /* -----------------------------------------------------------*/
1605: /*@
1606:    SNESCreate - Creates a nonlinear solver context.

1608:    Collective

1610:    Input Parameters:
1611: .  comm - MPI communicator

1613:    Output Parameter:
1614: .  outsnes - the new SNES context

1616:    Options Database Keys:
1617: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1618:                and no preconditioning matrix
1619: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1620:                products, and a user-provided preconditioning matrix
1621:                as set by SNESSetJacobian()
1622: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1624:    Level: beginner

1626:    Developer Notes:
1627:     SNES always creates a KSP object even though many SNES methods do not use it. This is
1628:                     unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1629:                     particular method does use KSP and regulates if the information about the KSP is printed
1630:                     in SNESView(). TSSetFromOptions() does call SNESSetFromOptions() which can lead to users being confused
1631:                     by help messages about meaningless SNES options.

1633:                     SNES always creates the snes->kspconvctx even though it is used by only one type. This should
1634:                     be fixed.

1636: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner()

1638: @*/
1639: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1640: {
1642:   SNES           snes;
1643:   SNESKSPEW      *kctx;

1647:   *outsnes = NULL;
1648:   SNESInitializePackage();

1650:   PetscHeaderCreate(snes,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1652:   snes->ops->converged    = SNESConvergedDefault;
1653:   snes->usesksp           = PETSC_TRUE;
1654:   snes->tolerancesset     = PETSC_FALSE;
1655:   snes->max_its           = 50;
1656:   snes->max_funcs         = 10000;
1657:   snes->norm              = 0.0;
1658:   snes->xnorm             = 0.0;
1659:   snes->ynorm             = 0.0;
1660:   snes->normschedule      = SNES_NORM_ALWAYS;
1661:   snes->functype          = SNES_FUNCTION_DEFAULT;
1662: #if defined(PETSC_USE_REAL_SINGLE)
1663:   snes->rtol              = 1.e-5;
1664: #else
1665:   snes->rtol              = 1.e-8;
1666: #endif
1667:   snes->ttol              = 0.0;
1668: #if defined(PETSC_USE_REAL_SINGLE)
1669:   snes->abstol            = 1.e-25;
1670: #else
1671:   snes->abstol            = 1.e-50;
1672: #endif
1673: #if defined(PETSC_USE_REAL_SINGLE)
1674:   snes->stol              = 1.e-5;
1675: #else
1676:   snes->stol              = 1.e-8;
1677: #endif
1678: #if defined(PETSC_USE_REAL_SINGLE)
1679:   snes->deltatol          = 1.e-6;
1680: #else
1681:   snes->deltatol          = 1.e-12;
1682: #endif
1683:   snes->divtol            = 1.e4;
1684:   snes->rnorm0            = 0;
1685:   snes->nfuncs            = 0;
1686:   snes->numFailures       = 0;
1687:   snes->maxFailures       = 1;
1688:   snes->linear_its        = 0;
1689:   snes->lagjacobian       = 1;
1690:   snes->jac_iter          = 0;
1691:   snes->lagjac_persist    = PETSC_FALSE;
1692:   snes->lagpreconditioner = 1;
1693:   snes->pre_iter          = 0;
1694:   snes->lagpre_persist    = PETSC_FALSE;
1695:   snes->numbermonitors    = 0;
1696:   snes->data              = 0;
1697:   snes->setupcalled       = PETSC_FALSE;
1698:   snes->ksp_ewconv        = PETSC_FALSE;
1699:   snes->nwork             = 0;
1700:   snes->work              = 0;
1701:   snes->nvwork            = 0;
1702:   snes->vwork             = 0;
1703:   snes->conv_hist_len     = 0;
1704:   snes->conv_hist_max     = 0;
1705:   snes->conv_hist         = NULL;
1706:   snes->conv_hist_its     = NULL;
1707:   snes->conv_hist_reset   = PETSC_TRUE;
1708:   snes->counters_reset    = PETSC_TRUE;
1709:   snes->vec_func_init_set = PETSC_FALSE;
1710:   snes->reason            = SNES_CONVERGED_ITERATING;
1711:   snes->npcside           = PC_RIGHT;
1712:   snes->setfromoptionscalled = 0;

1714:   snes->mf          = PETSC_FALSE;
1715:   snes->mf_operator = PETSC_FALSE;
1716:   snes->mf_version  = 1;

1718:   snes->numLinearSolveFailures = 0;
1719:   snes->maxLinearSolveFailures = 1;

1721:   snes->vizerotolerance = 1.e-8;
1722: #if defined(PETSC_USE_DEBUG)
1723:   snes->checkjacdomainerror = PETSC_TRUE;
1724: #else
1725:   snes->checkjacdomainerror = PETSC_FALSE;
1726: #endif

1728:   /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1729:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

1731:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1732:   PetscNewLog(snes,&kctx);

1734:   snes->kspconvctx  = (void*)kctx;
1735:   kctx->version     = 2;
1736:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1737:                              this was too large for some test cases */
1738:   kctx->rtol_last   = 0.0;
1739:   kctx->rtol_max    = .9;
1740:   kctx->gamma       = 1.0;
1741:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1742:   kctx->alpha2      = kctx->alpha;
1743:   kctx->threshold   = .1;
1744:   kctx->lresid_last = 0.0;
1745:   kctx->norm_last   = 0.0;

1747:   *outsnes = snes;
1748:   return(0);
1749: }

1751: /*MC
1752:     SNESFunction - Functional form used to convey the nonlinear function to be solved by SNES

1754:      Synopsis:
1755:      #include "petscsnes.h"
1756:      PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1758:      Input Parameters:
1759: +     snes - the SNES context
1760: .     x    - state at which to evaluate residual
1761: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1763:      Output Parameter:
1764: .     f  - vector to put residual (function value)

1766:    Level: intermediate

1768: .seealso:   SNESSetFunction(), SNESGetFunction()
1769: M*/

1771: /*@C
1772:    SNESSetFunction - Sets the function evaluation routine and function
1773:    vector for use by the SNES routines in solving systems of nonlinear
1774:    equations.

1776:    Logically Collective on SNES

1778:    Input Parameters:
1779: +  snes - the SNES context
1780: .  r - vector to store function value
1781: .  f - function evaluation routine; see SNESFunction for calling sequence details
1782: -  ctx - [optional] user-defined context for private data for the
1783:          function evaluation routine (may be NULL)

1785:    Notes:
1786:    The Newton-like methods typically solve linear systems of the form
1787: $      f'(x) x = -f(x),
1788:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1790:    Level: beginner

1792: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1793: @*/
1794: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1795: {
1797:   DM             dm;

1801:   if (r) {
1804:     PetscObjectReference((PetscObject)r);
1805:     VecDestroy(&snes->vec_func);

1807:     snes->vec_func = r;
1808:   }
1809:   SNESGetDM(snes,&dm);
1810:   DMSNESSetFunction(dm,f,ctx);
1811:   return(0);
1812: }


1815: /*@C
1816:    SNESSetInitialFunction - Sets the function vector to be used as the
1817:    function norm at the initialization of the method.  In some
1818:    instances, the user has precomputed the function before calling
1819:    SNESSolve.  This function allows one to avoid a redundant call
1820:    to SNESComputeFunction in that case.

1822:    Logically Collective on SNES

1824:    Input Parameters:
1825: +  snes - the SNES context
1826: -  f - vector to store function value

1828:    Notes:
1829:    This should not be modified during the solution procedure.

1831:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1833:    Level: developer

1835: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1836: @*/
1837: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1838: {
1840:   Vec            vec_func;

1846:   if (snes->npcside== PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1847:     snes->vec_func_init_set = PETSC_FALSE;
1848:     return(0);
1849:   }
1850:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1851:   VecCopy(f, vec_func);

1853:   snes->vec_func_init_set = PETSC_TRUE;
1854:   return(0);
1855: }

1857: /*@
1858:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1859:    of the SNES method.

1861:    Logically Collective on SNES

1863:    Input Parameters:
1864: +  snes - the SNES context
1865: -  normschedule - the frequency of norm computation

1867:    Options Database Key:
1868: .  -snes_norm_schedule <none, always, initialonly, finalonly, initalfinalonly>

1870:    Notes:
1871:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1872:    of the nonlinear function and the taking of its norm at every iteration to
1873:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1874:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1875:    may either be monitored for convergence or not.  As these are often used as nonlinear
1876:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1877:    their solution.

1879:    Level: developer

1881: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1882: @*/
1883: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1884: {
1887:   snes->normschedule = normschedule;
1888:   return(0);
1889: }


1892: /*@
1893:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1894:    of the SNES method.

1896:    Logically Collective on SNES

1898:    Input Parameters:
1899: +  snes - the SNES context
1900: -  normschedule - the type of the norm used

1902:    Level: advanced

1904: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1905: @*/
1906: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1907: {
1910:   *normschedule = snes->normschedule;
1911:   return(0);
1912: }


1915: /*@
1916:   SNESSetFunctionNorm - Sets the last computed residual norm.

1918:   Logically Collective on SNES

1920:   Input Parameters:
1921: + snes - the SNES context

1923: - normschedule - the frequency of norm computation

1925:   Level: developer

1927: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1928: @*/
1929: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
1930: {
1933:   snes->norm = norm;
1934:   return(0);
1935: }

1937: /*@
1938:   SNESGetFunctionNorm - Gets the last computed norm of the residual

1940:   Not Collective

1942:   Input Parameter:
1943: . snes - the SNES context

1945:   Output Parameter:
1946: . norm - the last computed residual norm

1948:   Level: developer

1950: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1951: @*/
1952: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
1953: {
1957:   *norm = snes->norm;
1958:   return(0);
1959: }

1961: /*@
1962:   SNESGetUpdateNorm - Gets the last computed norm of the Newton update

1964:   Not Collective

1966:   Input Parameter:
1967: . snes - the SNES context

1969:   Output Parameter:
1970: . ynorm - the last computed update norm

1972:   Level: developer

1974: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), SNESGetFunctionNorm()
1975: @*/
1976: PetscErrorCode SNESGetUpdateNorm(SNES snes, PetscReal *ynorm)
1977: {
1981:   *ynorm = snes->ynorm;
1982:   return(0);
1983: }

1985: /*@
1986:   SNESGetSolutionNorm - Gets the last computed norm of the solution

1988:   Not Collective

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

1993:   Output Parameter:
1994: . xnorm - the last computed solution norm

1996:   Level: developer

1998: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), SNESGetFunctionNorm(), SNESGetUpdateNorm()
1999: @*/
2000: PetscErrorCode SNESGetSolutionNorm(SNES snes, PetscReal *xnorm)
2001: {
2005:   *xnorm = snes->xnorm;
2006:   return(0);
2007: }

2009: /*@C
2010:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
2011:    of the SNES method.

2013:    Logically Collective on SNES

2015:    Input Parameters:
2016: +  snes - the SNES context
2017: -  normschedule - the frequency of norm computation

2019:    Notes:
2020:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
2021:    of the nonlinear function and the taking of its norm at every iteration to
2022:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
2023:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
2024:    may either be monitored for convergence or not.  As these are often used as nonlinear
2025:    preconditioners, monitoring the norm of their error is not a useful enterprise within
2026:    their solution.

2028:    Level: developer

2030: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2031: @*/
2032: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
2033: {
2036:   snes->functype = type;
2037:   return(0);
2038: }


2041: /*@C
2042:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
2043:    of the SNES method.

2045:    Logically Collective on SNES

2047:    Input Parameters:
2048: +  snes - the SNES context
2049: -  normschedule - the type of the norm used

2051:    Level: advanced

2053: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
2054: @*/
2055: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
2056: {
2059:   *type = snes->functype;
2060:   return(0);
2061: }

2063: /*MC
2064:     SNESNGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

2066:      Synopsis:
2067:      #include <petscsnes.h>
2068: $    SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);

2070: +  X   - solution vector
2071: .  B   - RHS vector
2072: -  ctx - optional user-defined Gauss-Seidel context

2074:    Level: intermediate

2076: .seealso:   SNESSetNGS(), SNESGetNGS()
2077: M*/

2079: /*@C
2080:    SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
2081:    use with composed nonlinear solvers.

2083:    Input Parameters:
2084: +  snes   - the SNES context
2085: .  f - function evaluation routine to apply Gauss-Seidel see SNESNGSFunction
2086: -  ctx    - [optional] user-defined context for private data for the
2087:             smoother evaluation routine (may be NULL)

2089:    Notes:
2090:    The NGS routines are used by the composed nonlinear solver to generate
2091:     a problem appropriate update to the solution, particularly FAS.

2093:    Level: intermediate

2095: .seealso: SNESGetFunction(), SNESComputeNGS()
2096: @*/
2097: PetscErrorCode SNESSetNGS(SNES snes,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
2098: {
2100:   DM             dm;

2104:   SNESGetDM(snes,&dm);
2105:   DMSNESSetNGS(dm,f,ctx);
2106:   return(0);
2107: }

2109: PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
2110: {
2112:   DM             dm;
2113:   DMSNES         sdm;

2116:   SNESGetDM(snes,&dm);
2117:   DMGetDMSNES(dm,&sdm);
2118:   if (!sdm->ops->computepfunction) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");
2119:   if (!sdm->ops->computepjacobian) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard Jacobian.");
2120:   /*  A(x)*x - b(x) */
2121:   PetscStackPush("SNES Picard user function");
2122:   (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
2123:   PetscStackPop;
2124:   PetscStackPush("SNES Picard user Jacobian");
2125:   (*sdm->ops->computepjacobian)(snes,x,snes->jacobian,snes->jacobian_pre,sdm->pctx);
2126:   PetscStackPop;
2127:   VecScale(f,-1.0);
2128:   MatMultAdd(snes->jacobian,x,f,f);
2129:   return(0);
2130: }

2132: PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat J,Mat B,void *ctx)
2133: {
2135:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2136:   return(0);
2137: }

2139: /*@C
2140:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

2142:    Logically Collective on SNES

2144:    Input Parameters:
2145: +  snes - the SNES context
2146: .  r - vector to store function value
2147: .  b - function evaluation routine
2148: .  Amat - matrix with which A(x) x - b(x) is to be computed
2149: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
2150: .  J  - function to compute matrix value, see SNESJacobianFunction for details on its calling sequence
2151: -  ctx - [optional] user-defined context for private data for the
2152:          function evaluation routine (may be NULL)

2154:    Notes:
2155:     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
2156:     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.

2158:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

2160: $     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}
2161: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

2163:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

2165:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2166:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

2168:    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
2169:    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
2170:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

2172:    Level: intermediate

2174: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard(), SNESJacobianFunction
2175: @*/
2176: 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)
2177: {
2179:   DM             dm;

2183:   SNESGetDM(snes, &dm);
2184:   DMSNESSetPicard(dm,b,J,ctx);
2185:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
2186:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
2187:   return(0);
2188: }

2190: /*@C
2191:    SNESGetPicard - Returns the context for the Picard iteration

2193:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

2195:    Input Parameter:
2196: .  snes - the SNES context

2198:    Output Parameter:
2199: +  r - the function (or NULL)
2200: .  f - the function (or NULL); see SNESFunction for calling sequence details
2201: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
2202: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
2203: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
2204: -  ctx - the function context (or NULL)

2206:    Level: advanced

2208: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
2209: @*/
2210: 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)
2211: {
2213:   DM             dm;

2217:   SNESGetFunction(snes,r,NULL,NULL);
2218:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
2219:   SNESGetDM(snes,&dm);
2220:   DMSNESGetPicard(dm,f,J,ctx);
2221:   return(0);
2222: }

2224: /*@C
2225:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

2227:    Logically Collective on SNES

2229:    Input Parameters:
2230: +  snes - the SNES context
2231: .  func - function evaluation routine
2232: -  ctx - [optional] user-defined context for private data for the
2233:          function evaluation routine (may be NULL)

2235:    Calling sequence of func:
2236: $    func (SNES snes,Vec x,void *ctx);

2238: .  f - function vector
2239: -  ctx - optional user-defined function context

2241:    Level: intermediate

2243: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
2244: @*/
2245: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
2246: {
2249:   if (func) snes->ops->computeinitialguess = func;
2250:   if (ctx)  snes->initialguessP            = ctx;
2251:   return(0);
2252: }

2254: /* --------------------------------------------------------------- */
2255: /*@C
2256:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
2257:    it assumes a zero right hand side.

2259:    Logically Collective on SNES

2261:    Input Parameter:
2262: .  snes - the SNES context

2264:    Output Parameter:
2265: .  rhs - the right hand side vector or NULL if the right hand side vector is null

2267:    Level: intermediate

2269: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2270: @*/
2271: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2272: {
2276:   *rhs = snes->vec_rhs;
2277:   return(0);
2278: }

2280: /*@
2281:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2283:    Collective on SNES

2285:    Input Parameters:
2286: +  snes - the SNES context
2287: -  x - input vector

2289:    Output Parameter:
2290: .  y - function vector, as set by SNESSetFunction()

2292:    Notes:
2293:    SNESComputeFunction() is typically used within nonlinear solvers
2294:    implementations, so most users would not generally call this routine
2295:    themselves.

2297:    Level: developer

2299: .seealso: SNESSetFunction(), SNESGetFunction()
2300: @*/
2301: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2302: {
2304:   DM             dm;
2305:   DMSNES         sdm;

2313:   VecValidValues(x,2,PETSC_TRUE);

2315:   SNESGetDM(snes,&dm);
2316:   DMGetDMSNES(dm,&sdm);
2317:   if (sdm->ops->computefunction) {
2318:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2319:       PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2320:     }
2321:     VecLockReadPush(x);
2322:     PetscStackPush("SNES user function");
2323:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2324:     PetscStackPop;
2325:     VecLockReadPop(x);
2326:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2327:       PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2328:     }
2329:   } else if (snes->vec_rhs) {
2330:     MatMult(snes->jacobian, x, y);
2331:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2332:   if (snes->vec_rhs) {
2333:     VecAXPY(y,-1.0,snes->vec_rhs);
2334:   }
2335:   snes->nfuncs++;
2336:   /*
2337:      domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2338:      propagate the value to all processes
2339:   */
2340:   if (snes->domainerror) {
2341:     VecSetInf(y);
2342:   }
2343:   return(0);
2344: }

2346: /*@
2347:    SNESComputeNGS - Calls the Gauss-Seidel function that has been set with  SNESSetNGS().

2349:    Collective on SNES

2351:    Input Parameters:
2352: +  snes - the SNES context
2353: .  x - input vector
2354: -  b - rhs vector

2356:    Output Parameter:
2357: .  x - new solution vector

2359:    Notes:
2360:    SNESComputeNGS() is typically used within composed nonlinear solver
2361:    implementations, so most users would not generally call this routine
2362:    themselves.

2364:    Level: developer

2366: .seealso: SNESSetNGS(), SNESComputeFunction()
2367: @*/
2368: PetscErrorCode  SNESComputeNGS(SNES snes,Vec b,Vec x)
2369: {
2371:   DM             dm;
2372:   DMSNES         sdm;

2380:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2381:   PetscLogEventBegin(SNES_NGSEval,snes,x,b,0);
2382:   SNESGetDM(snes,&dm);
2383:   DMGetDMSNES(dm,&sdm);
2384:   if (sdm->ops->computegs) {
2385:     if (b) {VecLockReadPush(b);}
2386:     PetscStackPush("SNES user NGS");
2387:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2388:     PetscStackPop;
2389:     if (b) {VecLockReadPop(b);}
2390:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2391:   PetscLogEventEnd(SNES_NGSEval,snes,x,b,0);
2392:   return(0);
2393: }

2395: PetscErrorCode SNESTestJacobian(SNES snes)
2396: {
2397:   Mat               A,B,C,D,jacobian;
2398:   Vec               x = snes->vec_sol,f = snes->vec_func;
2399:   PetscErrorCode    ierr;
2400:   PetscReal         nrm,gnorm;
2401:   PetscReal         threshold = 1.e-5;
2402:   PetscInt          m,n,M,N;
2403:   void              *functx;
2404:   PetscBool         complete_print = PETSC_FALSE,threshold_print = PETSC_FALSE,test = PETSC_FALSE,flg;
2405:   PetscViewer       viewer,mviewer;
2406:   MPI_Comm          comm;
2407:   PetscInt          tabs;
2408:   static PetscBool  directionsprinted = PETSC_FALSE;
2409:   PetscViewerFormat format;

2412:   PetscObjectOptionsBegin((PetscObject)snes);
2413:   PetscOptionsName("-snes_test_jacobian","Compare hand-coded and finite difference Jacobians","None",&test);
2414:   PetscOptionsReal("-snes_test_jacobian", "Threshold for element difference between hand-coded and finite difference being meaningful", "None", threshold, &threshold,NULL);
2415:   PetscOptionsViewer("-snes_test_jacobian_view","View difference between hand-coded and finite difference Jacobians element entries","None",&mviewer,&format,&complete_print);
2416:   if (!complete_print) {
2417:     PetscOptionsViewer("-snes_test_jacobian_display","Display difference between hand-coded and finite difference Jacobians","None",&mviewer,&format,&complete_print);
2418:   }
2419:   /* for compatibility with PETSc 3.9 and older. */
2420:   PetscOptionsReal("-snes_test_jacobian_display_threshold", "Display difference between hand-coded and finite difference Jacobians which exceed input threshold", "None", threshold, &threshold, &threshold_print);
2421:   PetscOptionsEnd();
2422:   if (!test) return(0);

2424:   PetscObjectGetComm((PetscObject)snes,&comm);
2425:   PetscViewerASCIIGetStdout(comm,&viewer);
2426:   PetscViewerASCIIGetTab(viewer, &tabs);
2427:   PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel);
2428:   PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian -------------\n");
2429:   if (!complete_print && !directionsprinted) {
2430:     PetscViewerASCIIPrintf(viewer,"  Run with -snes_test_jacobian_view and optionally -snes_test_jacobian <threshold> to show difference\n");
2431:     PetscViewerASCIIPrintf(viewer,"    of hand-coded and finite difference Jacobian entries greater than <threshold>.\n");
2432:   }
2433:   if (!directionsprinted) {
2434:     PetscViewerASCIIPrintf(viewer,"  Testing hand-coded Jacobian, if (for double precision runs) ||J - Jfd||_F/||J||_F is\n");
2435:     PetscViewerASCIIPrintf(viewer,"    O(1.e-8), the hand-coded Jacobian is probably correct.\n");
2436:     directionsprinted = PETSC_TRUE;
2437:   }
2438:   if (complete_print) {
2439:     PetscViewerPushFormat(mviewer,format);
2440:   }

2442:   PetscObjectTypeCompare((PetscObject)snes->jacobian,MATMFFD,&flg);
2443:   if (!flg) jacobian = snes->jacobian;
2444:   else jacobian = snes->jacobian_pre;

2446:   if (!x) {
2447:     MatCreateVecs(jacobian, &x, NULL);
2448:   } else {
2449:     PetscObjectReference((PetscObject) x);
2450:   }
2451:   if (!f) {
2452:     VecDuplicate(x, &f);
2453:   } else {
2454:     PetscObjectReference((PetscObject) f);
2455:   }
2456:   /* evaluate the function at this point because SNESComputeJacobianDefault() assumes that the function has been evaluated and put into snes->vec_func */
2457:   SNESComputeFunction(snes,x,f);
2458:   VecDestroy(&f);

2460:   while (jacobian) {
2461:     PetscObjectTypeCompareAny((PetscObject)jacobian,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2462:     if (flg) {
2463:       A    = jacobian;
2464:       PetscObjectReference((PetscObject)A);
2465:     } else {
2466:       MatComputeOperator(jacobian,MATAIJ,&A);
2467:     }

2469:     MatCreate(PetscObjectComm((PetscObject)A),&B);
2470:     MatGetSize(A,&M,&N);
2471:     MatGetLocalSize(A,&m,&n);
2472:     MatSetSizes(B,m,n,M,N);
2473:     MatSetType(B,((PetscObject)A)->type_name);
2474:     MatSetUp(B);
2475:     MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2477:     SNESGetFunction(snes,NULL,NULL,&functx);
2478:     SNESComputeJacobianDefault(snes,x,B,B,functx);

2480:     MatDuplicate(B,MAT_COPY_VALUES,&D);
2481:     MatAYPX(D,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2482:     MatNorm(D,NORM_FROBENIUS,&nrm);
2483:     MatNorm(A,NORM_FROBENIUS,&gnorm);
2484:     MatDestroy(&D);
2485:     if (!gnorm) gnorm = 1; /* just in case */
2486:     PetscViewerASCIIPrintf(viewer,"  ||J - Jfd||_F/||J||_F = %g, ||J - Jfd||_F = %g\n",(double)(nrm/gnorm),(double)nrm);

2488:     if (complete_print) {
2489:       PetscViewerASCIIPrintf(viewer,"  Hand-coded Jacobian ----------\n");
2490:       MatView(jacobian,mviewer);
2491:       PetscViewerASCIIPrintf(viewer,"  Finite difference Jacobian ----------\n");
2492:       MatView(B,mviewer);
2493:     }

2495:     if (threshold_print || complete_print) {
2496:       PetscInt          Istart, Iend, *ccols, bncols, cncols, j, row;
2497:       PetscScalar       *cvals;
2498:       const PetscInt    *bcols;
2499:       const PetscScalar *bvals;

2501:       MatAYPX(B,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2502:       MatCreate(PetscObjectComm((PetscObject)A),&C);
2503:       MatSetSizes(C,m,n,M,N);
2504:       MatSetType(C,((PetscObject)A)->type_name);
2505:       MatSetUp(C);
2506:       MatSetOption(C,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);
2507:       MatGetOwnershipRange(B,&Istart,&Iend);

2509:       for (row = Istart; row < Iend; row++) {
2510:         MatGetRow(B,row,&bncols,&bcols,&bvals);
2511:         PetscMalloc2(bncols,&ccols,bncols,&cvals);
2512:         for (j = 0, cncols = 0; j < bncols; j++) {
2513:           if (PetscAbsScalar(bvals[j]) > threshold) {
2514:             ccols[cncols] = bcols[j];
2515:             cvals[cncols] = bvals[j];
2516:             cncols += 1;
2517:           }
2518:         }
2519:         if (cncols) {
2520:           MatSetValues(C,1,&row,cncols,ccols,cvals,INSERT_VALUES);
2521:         }
2522:         MatRestoreRow(B,row,&bncols,&bcols,&bvals);
2523:         PetscFree2(ccols,cvals);
2524:       }
2525:       MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
2526:       MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
2527:       PetscViewerASCIIPrintf(viewer,"  Hand-coded minus finite-difference Jacobian with tolerance %g ----------\n",(double)threshold);
2528:       MatView(C,complete_print ? mviewer : viewer);
2529:       MatDestroy(&C);
2530:     }
2531:     MatDestroy(&A);
2532:     MatDestroy(&B);

2534:     if (jacobian != snes->jacobian_pre) {
2535:       jacobian = snes->jacobian_pre;
2536:       PetscViewerASCIIPrintf(viewer,"  ---------- Testing Jacobian for preconditioner -------------\n");
2537:     }
2538:     else jacobian = NULL;
2539:   }
2540:   VecDestroy(&x);
2541:   if (complete_print) {
2542:     PetscViewerPopFormat(mviewer);
2543:   }
2544:   if (mviewer) { PetscViewerDestroy(&mviewer); }
2545:   PetscViewerASCIISetTab(viewer,tabs);
2546:   return(0);
2547: }

2549: /*@
2550:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2552:    Collective on SNES

2554:    Input Parameters:
2555: +  snes - the SNES context
2556: -  x - input vector

2558:    Output Parameters:
2559: +  A - Jacobian matrix
2560: -  B - optional preconditioning matrix

2562:   Options Database Keys:
2563: +    -snes_lag_preconditioner <lag>
2564: .    -snes_lag_jacobian <lag>
2565: .    -snes_test_jacobian - compare the user provided Jacobian with one compute via finite differences to check for errors
2566: .    -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
2567: .    -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
2568: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2569: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2570: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2571: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2572: .    -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2573: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2574: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2575: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2576: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2577: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2578: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2581:    Notes:
2582:    Most users should not need to explicitly call this routine, as it
2583:    is used internally within the nonlinear solvers.

2585:    Developer Notes:
2586:     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
2587:       for with the SNESType of test that has been removed.

2589:    Level: developer

2591: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2592: @*/
2593: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat A,Mat B)
2594: {
2596:   PetscBool      flag;
2597:   DM             dm;
2598:   DMSNES         sdm;
2599:   KSP            ksp;

2605:   VecValidValues(X,2,PETSC_TRUE);
2606:   SNESGetDM(snes,&dm);
2607:   DMGetDMSNES(dm,&sdm);

2609:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2611:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2613:   if (snes->lagjacobian == -2) {
2614:     snes->lagjacobian = -1;

2616:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2617:   } else if (snes->lagjacobian == -1) {
2618:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2619:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2620:     if (flag) {
2621:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2622:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2623:     }
2624:     return(0);
2625:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2626:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2627:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2628:     if (flag) {
2629:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2630:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2631:     }
2632:     return(0);
2633:   }
2634:   if (snes->npc && snes->npcside== PC_LEFT) {
2635:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2636:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2637:       return(0);
2638:   }

2640:   PetscLogEventBegin(SNES_JacobianEval,snes,X,A,B);
2641:   VecLockReadPush(X);
2642:   PetscStackPush("SNES user Jacobian function");
2643:   (*sdm->ops->computejacobian)(snes,X,A,B,sdm->jacobianctx);
2644:   PetscStackPop;
2645:   VecLockReadPop(X);
2646:   PetscLogEventEnd(SNES_JacobianEval,snes,X,A,B);

2648:   /* the next line ensures that snes->ksp exists */
2649:   SNESGetKSP(snes,&ksp);
2650:   if (snes->lagpreconditioner == -2) {
2651:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");
2652:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2653:     snes->lagpreconditioner = -1;
2654:   } else if (snes->lagpreconditioner == -1) {
2655:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2656:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2657:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2658:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2659:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2660:   } else {
2661:     PetscInfo(snes,"Rebuilding preconditioner\n");
2662:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2663:   }

2665:   SNESTestJacobian(snes);
2666:   /* make sure user returned a correct Jacobian and preconditioner */
2669:   {
2670:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2671:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit",NULL,NULL,&flag);
2672:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",NULL,NULL,&flag_draw);
2673:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",NULL,NULL,&flag_contour);
2674:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject) snes)->options,((PetscObject)snes)->prefix,"-snes_compare_operator",NULL,NULL,&flag_operator);
2675:     if (flag || flag_draw || flag_contour) {
2676:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2677:       PetscViewer  vdraw,vstdout;
2678:       PetscBool    flg;
2679:       if (flag_operator) {
2680:         MatComputeOperator(A,MATAIJ,&Bexp_mine);
2681:         Bexp = Bexp_mine;
2682:       } else {
2683:         /* See if the preconditioning matrix can be viewed and added directly */
2684:         PetscObjectTypeCompareAny((PetscObject)B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2685:         if (flg) Bexp = B;
2686:         else {
2687:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2688:           MatComputeOperator(B,MATAIJ,&Bexp_mine);
2689:           Bexp = Bexp_mine;
2690:         }
2691:       }
2692:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2693:       SNESComputeJacobianDefault(snes,X,FDexp,FDexp,NULL);
2694:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2695:       if (flag_draw || flag_contour) {
2696:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2697:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2698:       } else vdraw = NULL;
2699:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2700:       if (flag) {MatView(Bexp,vstdout);}
2701:       if (vdraw) {MatView(Bexp,vdraw);}
2702:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2703:       if (flag) {MatView(FDexp,vstdout);}
2704:       if (vdraw) {MatView(FDexp,vdraw);}
2705:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2706:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2707:       if (flag) {MatView(FDexp,vstdout);}
2708:       if (vdraw) {              /* Always use contour for the difference */
2709:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2710:         MatView(FDexp,vdraw);
2711:         PetscViewerPopFormat(vdraw);
2712:       }
2713:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2714:       PetscViewerDestroy(&vdraw);
2715:       MatDestroy(&Bexp_mine);
2716:       MatDestroy(&FDexp);
2717:     }
2718:   }
2719:   {
2720:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2721:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2722:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring",NULL,NULL,&flag);
2723:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_display",NULL,NULL,&flag_display);
2724:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",NULL,NULL,&flag_draw);
2725:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",NULL,NULL,&flag_contour);
2726:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",NULL,NULL,&flag_threshold);
2727:     if (flag_threshold) {
2728:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2729:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2730:     }
2731:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2732:       Mat            Bfd;
2733:       PetscViewer    vdraw,vstdout;
2734:       MatColoring    coloring;
2735:       ISColoring     iscoloring;
2736:       MatFDColoring  matfdcoloring;
2737:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2738:       void           *funcctx;
2739:       PetscReal      norm1,norm2,normmax;

2741:       MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2742:       MatColoringCreate(Bfd,&coloring);
2743:       MatColoringSetType(coloring,MATCOLORINGSL);
2744:       MatColoringSetFromOptions(coloring);
2745:       MatColoringApply(coloring,&iscoloring);
2746:       MatColoringDestroy(&coloring);
2747:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2748:       MatFDColoringSetFromOptions(matfdcoloring);
2749:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2750:       ISColoringDestroy(&iscoloring);

2752:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2753:       SNESGetFunction(snes,NULL,&func,&funcctx);
2754:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2755:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2756:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2757:       MatFDColoringSetFromOptions(matfdcoloring);
2758:       MatFDColoringApply(Bfd,matfdcoloring,X,snes);
2759:       MatFDColoringDestroy(&matfdcoloring);

2761:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2762:       if (flag_draw || flag_contour) {
2763:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2764:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2765:       } else vdraw = NULL;
2766:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2767:       if (flag_display) {MatView(B,vstdout);}
2768:       if (vdraw) {MatView(B,vdraw);}
2769:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2770:       if (flag_display) {MatView(Bfd,vstdout);}
2771:       if (vdraw) {MatView(Bfd,vdraw);}
2772:       MatAYPX(Bfd,-1.0,B,SAME_NONZERO_PATTERN);
2773:       MatNorm(Bfd,NORM_1,&norm1);
2774:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2775:       MatNorm(Bfd,NORM_MAX,&normmax);
2776:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2777:       if (flag_display) {MatView(Bfd,vstdout);}
2778:       if (vdraw) {              /* Always use contour for the difference */
2779:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2780:         MatView(Bfd,vdraw);
2781:         PetscViewerPopFormat(vdraw);
2782:       }
2783:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2785:       if (flag_threshold) {
2786:         PetscInt bs,rstart,rend,i;
2787:         MatGetBlockSize(B,&bs);
2788:         MatGetOwnershipRange(B,&rstart,&rend);
2789:         for (i=rstart; i<rend; i++) {
2790:           const PetscScalar *ba,*ca;
2791:           const PetscInt    *bj,*cj;
2792:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2793:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2794:           MatGetRow(B,i,&bn,&bj,&ba);
2795:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2796:           if (bn != cn) SETERRQ(((PetscObject)A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2797:           for (j=0; j<bn; j++) {
2798:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2799:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2800:               maxentrycol = bj[j];
2801:               maxentry    = PetscRealPart(ba[j]);
2802:             }
2803:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2804:               maxdiffcol = bj[j];
2805:               maxdiff    = PetscRealPart(ca[j]);
2806:             }
2807:             if (rdiff > maxrdiff) {
2808:               maxrdiffcol = bj[j];
2809:               maxrdiff    = rdiff;
2810:             }
2811:           }
2812:           if (maxrdiff > 1) {
2813:             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);
2814:             for (j=0; j<bn; j++) {
2815:               PetscReal rdiff;
2816:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2817:               if (rdiff > 1) {
2818:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2819:               }
2820:             }
2821:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2822:           }
2823:           MatRestoreRow(B,i,&bn,&bj,&ba);
2824:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2825:         }
2826:       }
2827:       PetscViewerDestroy(&vdraw);
2828:       MatDestroy(&Bfd);
2829:     }
2830:   }
2831:   return(0);
2832: }

2834: /*MC
2835:     SNESJacobianFunction - Function used to convey the nonlinear Jacobian of the function to be solved by SNES

2837:      Synopsis:
2838:      #include "petscsnes.h"
2839:      PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);

2841: +  x - input vector
2842: .  Amat - the matrix that defines the (approximate) Jacobian
2843: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2844: -  ctx - [optional] user-defined Jacobian context

2846:    Level: intermediate

2848: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2849: M*/

2851: /*@C
2852:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2853:    location to store the matrix.

2855:    Logically Collective on SNES

2857:    Input Parameters:
2858: +  snes - the SNES context
2859: .  Amat - the matrix that defines the (approximate) Jacobian
2860: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2861: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value), see SNESJacobianFunction for details
2862: -  ctx - [optional] user-defined context for private data for the
2863:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2865:    Notes:
2866:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2867:    each matrix.

2869:    If you know the operator Amat has a null space you can use MatSetNullSpace() and MatSetTransposeNullSpace() to supply the null
2870:    space to Amat and the KSP solvers will automatically use that null space as needed during the solution process.

2872:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2873:    must be a MatFDColoring.

2875:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2876:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2878:    Level: beginner

2880: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J,
2881:           SNESSetPicard(), SNESJacobianFunction
2882: @*/
2883: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2884: {
2886:   DM             dm;

2894:   SNESGetDM(snes,&dm);
2895:   DMSNESSetJacobian(dm,J,ctx);
2896:   if (Amat) {
2897:     PetscObjectReference((PetscObject)Amat);
2898:     MatDestroy(&snes->jacobian);

2900:     snes->jacobian = Amat;
2901:   }
2902:   if (Pmat) {
2903:     PetscObjectReference((PetscObject)Pmat);
2904:     MatDestroy(&snes->jacobian_pre);

2906:     snes->jacobian_pre = Pmat;
2907:   }
2908:   return(0);
2909: }

2911: /*@C
2912:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2913:    provided context for evaluating the Jacobian.

2915:    Not Collective, but Mat object will be parallel if SNES object is

2917:    Input Parameter:
2918: .  snes - the nonlinear solver context

2920:    Output Parameters:
2921: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
2922: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
2923: .  J - location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
2924: -  ctx - location to stash Jacobian ctx (or NULL)

2926:    Level: advanced

2928: .seealso: SNESSetJacobian(), SNESComputeJacobian(), SNESJacobianFunction, SNESGetFunction()
2929: @*/
2930: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
2931: {
2933:   DM             dm;
2934:   DMSNES         sdm;

2938:   if (Amat) *Amat = snes->jacobian;
2939:   if (Pmat) *Pmat = snes->jacobian_pre;
2940:   SNESGetDM(snes,&dm);
2941:   DMGetDMSNES(dm,&sdm);
2942:   if (J) *J = sdm->ops->computejacobian;
2943:   if (ctx) *ctx = sdm->jacobianctx;
2944:   return(0);
2945: }

2947: /*@
2948:    SNESSetUp - Sets up the internal data structures for the later use
2949:    of a nonlinear solver.

2951:    Collective on SNES

2953:    Input Parameters:
2954: .  snes - the SNES context

2956:    Notes:
2957:    For basic use of the SNES solvers the user need not explicitly call
2958:    SNESSetUp(), since these actions will automatically occur during
2959:    the call to SNESSolve().  However, if one wishes to control this
2960:    phase separately, SNESSetUp() should be called after SNESCreate()
2961:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

2963:    Level: advanced

2965: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
2966: @*/
2967: PetscErrorCode  SNESSetUp(SNES snes)
2968: {
2970:   DM             dm;
2971:   DMSNES         sdm;
2972:   SNESLineSearch linesearch, pclinesearch;
2973:   void           *lsprectx,*lspostctx;
2974:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
2975:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
2976:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2977:   Vec            f,fpc;
2978:   void           *funcctx;
2979:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
2980:   void           *jacctx,*appctx;
2981:   Mat            j,jpre;

2985:   if (snes->setupcalled) return(0);
2986:   PetscLogEventBegin(SNES_Setup,snes,0,0,0);

2988:   if (!((PetscObject)snes)->type_name) {
2989:     SNESSetType(snes,SNESNEWTONLS);
2990:   }

2992:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

2994:   SNESGetDM(snes,&dm);
2995:   DMGetDMSNES(dm,&sdm);
2996:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
2997:   if (!sdm->ops->computejacobian) {
2998:     DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
2999:   }
3000:   if (!snes->vec_func) {
3001:     DMCreateGlobalVector(dm,&snes->vec_func);
3002:   }

3004:   if (!snes->ksp) {
3005:     SNESGetKSP(snes, &snes->ksp);
3006:   }

3008:   if (snes->linesearch) {
3009:     SNESGetLineSearch(snes, &snes->linesearch);
3010:     SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);
3011:   }

3013:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3014:     snes->mf          = PETSC_TRUE;
3015:     snes->mf_operator = PETSC_FALSE;
3016:   }

3018:   if (snes->npc) {
3019:     /* copy the DM over */
3020:     SNESGetDM(snes,&dm);
3021:     SNESSetDM(snes->npc,dm);

3023:     SNESGetFunction(snes,&f,&func,&funcctx);
3024:     VecDuplicate(f,&fpc);
3025:     SNESSetFunction(snes->npc,fpc,func,funcctx);
3026:     SNESGetJacobian(snes,&j,&jpre,&jac,&jacctx);
3027:     SNESSetJacobian(snes->npc,j,jpre,jac,jacctx);
3028:     SNESGetApplicationContext(snes,&appctx);
3029:     SNESSetApplicationContext(snes->npc,appctx);
3030:     VecDestroy(&fpc);

3032:     /* copy the function pointers over */
3033:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->npc);

3035:     /* default to 1 iteration */
3036:     SNESSetTolerances(snes->npc,0.0,0.0,0.0,1,snes->npc->max_funcs);
3037:     if (snes->npcside==PC_RIGHT) {
3038:       SNESSetNormSchedule(snes->npc,SNES_NORM_FINAL_ONLY);
3039:     } else {
3040:       SNESSetNormSchedule(snes->npc,SNES_NORM_NONE);
3041:     }
3042:     SNESSetFromOptions(snes->npc);

3044:     /* copy the line search context over */
3045:     if (snes->linesearch && snes->npc->linesearch) {
3046:       SNESGetLineSearch(snes,&linesearch);
3047:       SNESGetLineSearch(snes->npc,&pclinesearch);
3048:       SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
3049:       SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
3050:       SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
3051:       SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
3052:       PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
3053:     }
3054:   }
3055:   if (snes->mf) {
3056:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
3057:   }
3058:   if (snes->ops->usercompute && !snes->user) {
3059:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
3060:   }

3062:   snes->jac_iter = 0;
3063:   snes->pre_iter = 0;

3065:   if (snes->ops->setup) {
3066:     (*snes->ops->setup)(snes);
3067:   }

3069:   if (snes->npc && (snes->npcside== PC_LEFT)) {
3070:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
3071:       if (snes->linesearch){
3072:         SNESGetLineSearch(snes,&linesearch);
3073:         SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultNPC);
3074:       }
3075:     }
3076:   }
3077:   PetscLogEventEnd(SNES_Setup,snes,0,0,0);
3078:   snes->setupcalled = PETSC_TRUE;
3079:   return(0);
3080: }

3082: /*@
3083:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

3085:    Collective on SNES

3087:    Input Parameter:
3088: .  snes - iterative context obtained from SNESCreate()

3090:    Level: intermediate

3092:    Notes:
3093:     Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

3095: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
3096: @*/
3097: PetscErrorCode  SNESReset(SNES snes)
3098: {

3103:   if (snes->ops->userdestroy && snes->user) {
3104:     (*snes->ops->userdestroy)((void**)&snes->user);
3105:     snes->user = NULL;
3106:   }
3107:   if (snes->npc) {
3108:     SNESReset(snes->npc);
3109:   }

3111:   if (snes->ops->reset) {
3112:     (*snes->ops->reset)(snes);
3113:   }
3114:   if (snes->ksp) {
3115:     KSPReset(snes->ksp);
3116:   }

3118:   if (snes->linesearch) {
3119:     SNESLineSearchReset(snes->linesearch);
3120:   }

3122:   VecDestroy(&snes->vec_rhs);
3123:   VecDestroy(&snes->vec_sol);
3124:   VecDestroy(&snes->vec_sol_update);
3125:   VecDestroy(&snes->vec_func);
3126:   MatDestroy(&snes->jacobian);
3127:   MatDestroy(&snes->jacobian_pre);
3128:   VecDestroyVecs(snes->nwork,&snes->work);
3129:   VecDestroyVecs(snes->nvwork,&snes->vwork);

3131:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

3133:   snes->nwork       = snes->nvwork = 0;
3134:   snes->setupcalled = PETSC_FALSE;
3135:   return(0);
3136: }

3138: /*@
3139:    SNESDestroy - Destroys the nonlinear solver context that was created
3140:    with SNESCreate().

3142:    Collective on SNES

3144:    Input Parameter:
3145: .  snes - the SNES context

3147:    Level: beginner

3149: .seealso: SNESCreate(), SNESSolve()
3150: @*/
3151: PetscErrorCode  SNESDestroy(SNES *snes)
3152: {

3156:   if (!*snes) return(0);
3158:   if (--((PetscObject)(*snes))->refct > 0) {*snes = 0; return(0);}

3160:   SNESReset((*snes));
3161:   SNESDestroy(&(*snes)->npc);

3163:   /* if memory was published with SAWs then destroy it */
3164:   PetscObjectSAWsViewOff((PetscObject)*snes);
3165:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

3167:   if ((*snes)->dm) {DMCoarsenHookRemove((*snes)->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,*snes);}
3168:   DMDestroy(&(*snes)->dm);
3169:   KSPDestroy(&(*snes)->ksp);
3170:   SNESLineSearchDestroy(&(*snes)->linesearch);

3172:   PetscFree((*snes)->kspconvctx);
3173:   if ((*snes)->ops->convergeddestroy) {
3174:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
3175:   }
3176:   if ((*snes)->conv_hist_alloc) {
3177:     PetscFree2((*snes)->conv_hist,(*snes)->conv_hist_its);
3178:   }
3179:   SNESMonitorCancel((*snes));
3180:   PetscHeaderDestroy(snes);
3181:   return(0);
3182: }

3184: /* ----------- Routines to set solver parameters ---------- */

3186: /*@
3187:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

3189:    Logically Collective on SNES

3191:    Input Parameters:
3192: +  snes - the SNES context
3193: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3194:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3196:    Options Database Keys:
3197: .    -snes_lag_preconditioner <lag>

3199:    Notes:
3200:    The default is 1
3201:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3202:    If  -1 is used before the very first nonlinear solve the preconditioner is still built because there is no previous preconditioner to use

3204:    Level: intermediate

3206: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian()

3208: @*/
3209: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
3210: {
3213:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3214:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3216:   snes->lagpreconditioner = lag;
3217:   return(0);
3218: }

3220: /*@
3221:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

3223:    Logically Collective on SNES

3225:    Input Parameters:
3226: +  snes - the SNES context
3227: -  steps - the number of refinements to do, defaults to 0

3229:    Options Database Keys:
3230: .    -snes_grid_sequence <steps>

3232:    Level: intermediate

3234:    Notes:
3235:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3237: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetGridSequence()

3239: @*/
3240: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
3241: {
3245:   snes->gridsequence = steps;
3246:   return(0);
3247: }

3249: /*@
3250:    SNESGetGridSequence - gets the number of steps of grid sequencing that SNES does

3252:    Logically Collective on SNES

3254:    Input Parameter:
3255: .  snes - the SNES context

3257:    Output Parameter:
3258: .  steps - the number of refinements to do, defaults to 0

3260:    Options Database Keys:
3261: .    -snes_grid_sequence <steps>

3263:    Level: intermediate

3265:    Notes:
3266:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3268: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetGridSequence()

3270: @*/
3271: PetscErrorCode  SNESGetGridSequence(SNES snes,PetscInt *steps)
3272: {
3275:   *steps = snes->gridsequence;
3276:   return(0);
3277: }

3279: /*@
3280:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

3282:    Not Collective

3284:    Input Parameter:
3285: .  snes - the SNES context

3287:    Output Parameter:
3288: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3289:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3291:    Options Database Keys:
3292: .    -snes_lag_preconditioner <lag>

3294:    Notes:
3295:    The default is 1
3296:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3298:    Level: intermediate

3300: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner()

3302: @*/
3303: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
3304: {
3307:   *lag = snes->lagpreconditioner;
3308:   return(0);
3309: }

3311: /*@
3312:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
3313:      often the preconditioner is rebuilt.

3315:    Logically Collective on SNES

3317:    Input Parameters:
3318: +  snes - the SNES context
3319: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3320:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

3322:    Options Database Keys:
3323: .    -snes_lag_jacobian <lag>

3325:    Notes:
3326:    The default is 1
3327:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3328:    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
3329:    at the next Newton step but never again (unless it is reset to another value)

3331:    Level: intermediate

3333: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobian()

3335: @*/
3336: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
3337: {
3340:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3341:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3343:   snes->lagjacobian = lag;
3344:   return(0);
3345: }

3347: /*@
3348:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

3350:    Not Collective

3352:    Input Parameter:
3353: .  snes - the SNES context

3355:    Output Parameter:
3356: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3357:          the Jacobian is built etc.

3359:    Options Database Keys:
3360: .    -snes_lag_jacobian <lag>

3362:    Notes:
3363:    The default is 1
3364:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3366:    Level: intermediate

3368: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner()

3370: @*/
3371: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
3372: {
3375:   *lag = snes->lagjacobian;
3376:   return(0);
3377: }

3379: /*@
3380:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

3382:    Logically collective on SNES

3384:    Input Parameter:
3385: +  snes - the SNES context
3386: -   flg - jacobian lagging persists if true

3388:    Options Database Keys:
3389: .    -snes_lag_jacobian_persists <flg>

3391:    Notes:
3392:     This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3393:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3394:    timesteps may present huge efficiency gains.

3396:    Level: developer

3398: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3400: @*/
3401: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3402: {
3406:   snes->lagjac_persist = flg;
3407:   return(0);
3408: }

3410: /*@
3411:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple solves

3413:    Logically Collective on SNES

3415:    Input Parameter:
3416: +  snes - the SNES context
3417: -   flg - preconditioner lagging persists if true

3419:    Options Database Keys:
3420: .    -snes_lag_jacobian_persists <flg>

3422:    Notes:
3423:     This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3424:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3425:    several timesteps may present huge efficiency gains.

3427:    Level: developer

3429: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3431: @*/
3432: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3433: {
3437:   snes->lagpre_persist = flg;
3438:   return(0);
3439: }

3441: /*@
3442:    SNESSetForceIteration - force SNESSolve() to take at least one iteration regardless of the initial residual norm

3444:    Logically Collective on SNES

3446:    Input Parameters:
3447: +  snes - the SNES context
3448: -  force - PETSC_TRUE require at least one iteration

3450:    Options Database Keys:
3451: .    -snes_force_iteration <force> - Sets forcing an iteration

3453:    Notes:
3454:    This is used sometimes with TS to prevent TS from detecting a false steady state solution

3456:    Level: intermediate

3458: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3459: @*/
3460: PetscErrorCode  SNESSetForceIteration(SNES snes,PetscBool force)
3461: {
3464:   snes->forceiteration = force;
3465:   return(0);
3466: }

3468: /*@
3469:    SNESGetForceIteration - Whether or not to force SNESSolve() take at least one iteration regardless of the initial residual norm

3471:    Logically Collective on SNES

3473:    Input Parameters:
3474: .  snes - the SNES context

3476:    Output Parameter:
3477: .  force - PETSC_TRUE requires at least one iteration.

3479:    Level: intermediate

3481: .seealso: SNESSetForceIteration(), SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3482: @*/
3483: PetscErrorCode  SNESGetForceIteration(SNES snes,PetscBool *force)
3484: {
3487:   *force = snes->forceiteration;
3488:   return(0);
3489: }

3491: /*@
3492:    SNESSetTolerances - Sets various parameters used in convergence tests.

3494:    Logically Collective on SNES

3496:    Input Parameters:
3497: +  snes - the SNES context
3498: .  abstol - absolute convergence tolerance
3499: .  rtol - relative convergence tolerance
3500: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3501: .  maxit - maximum number of iterations
3502: -  maxf - maximum number of function evaluations (-1 indicates no limit)

3504:    Options Database Keys:
3505: +    -snes_atol <abstol> - Sets abstol
3506: .    -snes_rtol <rtol> - Sets rtol
3507: .    -snes_stol <stol> - Sets stol
3508: .    -snes_max_it <maxit> - Sets maxit
3509: -    -snes_max_funcs <maxf> - Sets maxf

3511:    Notes:
3512:    The default maximum number of iterations is 50.
3513:    The default maximum number of function evaluations is 1000.

3515:    Level: intermediate

3517: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance(), SNESSetForceIteration()
3518: @*/
3519: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3520: {

3529:   if (abstol != PETSC_DEFAULT) {
3530:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3531:     snes->abstol = abstol;
3532:   }
3533:   if (rtol != PETSC_DEFAULT) {
3534:     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);
3535:     snes->rtol = rtol;
3536:   }
3537:   if (stol != PETSC_DEFAULT) {
3538:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3539:     snes->stol = stol;
3540:   }
3541:   if (maxit != PETSC_DEFAULT) {
3542:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3543:     snes->max_its = maxit;
3544:   }
3545:   if (maxf != PETSC_DEFAULT) {
3546:     if (maxf < -1) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be -1 or nonnegative",maxf);
3547:     snes->max_funcs = maxf;
3548:   }
3549:   snes->tolerancesset = PETSC_TRUE;
3550:   return(0);
3551: }

3553: /*@
3554:    SNESSetDivergenceTolerance - Sets the divergence tolerance used for the SNES divergence test.

3556:    Logically Collective on SNES

3558:    Input Parameters:
3559: +  snes - the SNES context
3560: -  divtol - the divergence tolerance. Use -1 to deactivate the test.

3562:    Options Database Keys:
3563: +    -snes_divergence_tolerance <divtol> - Sets divtol

3565:    Notes:
3566:    The default divergence tolerance is 1e4.

3568:    Level: intermediate

3570: .seealso: SNESSetTolerances(), SNESGetDivergenceTolerance
3571: @*/
3572: PetscErrorCode  SNESSetDivergenceTolerance(SNES snes,PetscReal divtol)
3573: {

3578:   if (divtol != PETSC_DEFAULT) {
3579:     snes->divtol = divtol;
3580:   }
3581:   else {
3582:     snes->divtol = 1.0e4;
3583:   }
3584:   return(0);
3585: }

3587: /*@
3588:    SNESGetTolerances - Gets various parameters used in convergence tests.

3590:    Not Collective

3592:    Input Parameters:
3593: +  snes - the SNES context
3594: .  atol - absolute convergence tolerance
3595: .  rtol - relative convergence tolerance
3596: .  stol -  convergence tolerance in terms of the norm
3597:            of the change in the solution between steps
3598: .  maxit - maximum number of iterations
3599: -  maxf - maximum number of function evaluations

3601:    Notes:
3602:    The user can specify NULL for any parameter that is not needed.

3604:    Level: intermediate

3606: .seealso: SNESSetTolerances()
3607: @*/
3608: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3609: {
3612:   if (atol)  *atol  = snes->abstol;
3613:   if (rtol)  *rtol  = snes->rtol;
3614:   if (stol)  *stol  = snes->stol;
3615:   if (maxit) *maxit = snes->max_its;
3616:   if (maxf)  *maxf  = snes->max_funcs;
3617:   return(0);
3618: }

3620: /*@
3621:    SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.

3623:    Not Collective

3625:    Input Parameters:
3626: +  snes - the SNES context
3627: -  divtol - divergence tolerance

3629:    Level: intermediate

3631: .seealso: SNESSetDivergenceTolerance()
3632: @*/
3633: PetscErrorCode  SNESGetDivergenceTolerance(SNES snes,PetscReal *divtol)
3634: {
3637:   if (divtol) *divtol = snes->divtol;
3638:   return(0);
3639: }

3641: /*@
3642:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3644:    Logically Collective on SNES

3646:    Input Parameters:
3647: +  snes - the SNES context
3648: -  tol - tolerance

3650:    Options Database Key:
3651: .  -snes_trtol <tol> - Sets tol

3653:    Level: intermediate

3655: .seealso: SNESSetTolerances()
3656: @*/
3657: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3658: {
3662:   snes->deltatol = tol;
3663:   return(0);
3664: }

3666: /*
3667:    Duplicate the lg monitors for SNES from KSP; for some reason with
3668:    dynamic libraries things don't work under Sun4 if we just use
3669:    macros instead of functions
3670: */
3671: PetscErrorCode  SNESMonitorLGResidualNorm(SNES snes,PetscInt it,PetscReal norm,void *ctx)
3672: {

3677:   KSPMonitorLGResidualNorm((KSP)snes,it,norm,ctx);
3678:   return(0);
3679: }

3681: PetscErrorCode  SNESMonitorLGCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscDrawLG *lgctx)
3682: {

3686:   KSPMonitorLGResidualNormCreate(comm,host,label,x,y,m,n,lgctx);
3687:   return(0);
3688: }

3690: PETSC_INTERN PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);

3692: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3693: {
3694:   PetscDrawLG      lg;
3695:   PetscErrorCode   ierr;
3696:   PetscReal        x,y,per;
3697:   PetscViewer      v = (PetscViewer)monctx;
3698:   static PetscReal prev; /* should be in the context */
3699:   PetscDraw        draw;

3703:   PetscViewerDrawGetDrawLG(v,0,&lg);
3704:   if (!n) {PetscDrawLGReset(lg);}
3705:   PetscDrawLGGetDraw(lg,&draw);
3706:   PetscDrawSetTitle(draw,"Residual norm");
3707:   x    = (PetscReal)n;
3708:   if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3709:   else y = -15.0;
3710:   PetscDrawLGAddPoint(lg,&x,&y);
3711:   if (n < 20 || !(n % 5) || snes->reason) {
3712:     PetscDrawLGDraw(lg);
3713:     PetscDrawLGSave(lg);
3714:   }

3716:   PetscViewerDrawGetDrawLG(v,1,&lg);
3717:   if (!n) {PetscDrawLGReset(lg);}
3718:   PetscDrawLGGetDraw(lg,&draw);
3719:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3720:    SNESMonitorRange_Private(snes,n,&per);
3721:   x    = (PetscReal)n;
3722:   y    = 100.0*per;
3723:   PetscDrawLGAddPoint(lg,&x,&y);
3724:   if (n < 20 || !(n % 5) || snes->reason) {
3725:     PetscDrawLGDraw(lg);
3726:     PetscDrawLGSave(lg);
3727:   }

3729:   PetscViewerDrawGetDrawLG(v,2,&lg);
3730:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3731:   PetscDrawLGGetDraw(lg,&draw);
3732:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3733:   x    = (PetscReal)n;
3734:   y    = (prev - rnorm)/prev;
3735:   PetscDrawLGAddPoint(lg,&x,&y);
3736:   if (n < 20 || !(n % 5) || snes->reason) {
3737:     PetscDrawLGDraw(lg);
3738:     PetscDrawLGSave(lg);
3739:   }

3741:   PetscViewerDrawGetDrawLG(v,3,&lg);
3742:   if (!n) {PetscDrawLGReset(lg);}
3743:   PetscDrawLGGetDraw(lg,&draw);
3744:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3745:   x    = (PetscReal)n;
3746:   y    = (prev - rnorm)/(prev*per);
3747:   if (n > 2) { /*skip initial crazy value */
3748:     PetscDrawLGAddPoint(lg,&x,&y);
3749:   }
3750:   if (n < 20 || !(n % 5) || snes->reason) {
3751:     PetscDrawLGDraw(lg);
3752:     PetscDrawLGSave(lg);
3753:   }
3754:   prev = rnorm;
3755:   return(0);
3756: }

3758: /*@
3759:    SNESMonitor - runs the user provided monitor routines, if they exist

3761:    Collective on SNES

3763:    Input Parameters:
3764: +  snes - nonlinear solver context obtained from SNESCreate()
3765: .  iter - iteration number
3766: -  rnorm - relative norm of the residual

3768:    Notes:
3769:    This routine is called by the SNES implementations.
3770:    It does not typically need to be called by the user.

3772:    Level: developer

3774: .seealso: SNESMonitorSet()
3775: @*/
3776: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3777: {
3779:   PetscInt       i,n = snes->numbermonitors;

3782:   VecLockReadPush(snes->vec_sol);
3783:   for (i=0; i<n; i++) {
3784:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3785:   }
3786:   VecLockReadPop(snes->vec_sol);
3787:   return(0);
3788: }

3790: /* ------------ Routines to set performance monitoring options ----------- */

3792: /*MC
3793:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3795:      Synopsis:
3796:      #include <petscsnes.h>
3797: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3799: +    snes - the SNES context
3800: .    its - iteration number
3801: .    norm - 2-norm function value (may be estimated)
3802: -    mctx - [optional] monitoring context

3804:    Level: advanced

3806: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3807: M*/

3809: /*@C
3810:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3811:    iteration of the nonlinear solver to display the iteration's
3812:    progress.

3814:    Logically Collective on SNES

3816:    Input Parameters:
3817: +  snes - the SNES context
3818: .  f - the monitor function, see SNESMonitorFunction for the calling sequence
3819: .  mctx - [optional] user-defined context for private data for the
3820:           monitor routine (use NULL if no context is desired)
3821: -  monitordestroy - [optional] routine that frees monitor context
3822:           (may be NULL)

3824:    Options Database Keys:
3825: +    -snes_monitor        - sets SNESMonitorDefault()
3826: .    -snes_monitor_lg_residualnorm    - sets line graph monitor,
3827:                             uses SNESMonitorLGCreate()
3828: -    -snes_monitor_cancel - cancels all monitors that have
3829:                             been hardwired into a code by
3830:                             calls to SNESMonitorSet(), but
3831:                             does not cancel those set via
3832:                             the options database.

3834:    Notes:
3835:    Several different monitoring routines may be set by calling
3836:    SNESMonitorSet() multiple times; all will be called in the
3837:    order in which they were set.

3839:    Fortran Notes:
3840:     Only a single monitor function can be set for each SNES object

3842:    Level: intermediate

3844: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3845: @*/
3846: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*f)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3847: {
3848:   PetscInt       i;
3850:   PetscBool      identical;

3854:   for (i=0; i<snes->numbermonitors;i++) {
3855:     PetscMonitorCompare((PetscErrorCode (*)(void))f,mctx,monitordestroy,(PetscErrorCode (*)(void))snes->monitor[i],snes->monitorcontext[i],snes->monitordestroy[i],&identical);
3856:     if (identical) return(0);
3857:   }
3858:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3859:   snes->monitor[snes->numbermonitors]          = f;
3860:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3861:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3862:   return(0);
3863: }

3865: /*@
3866:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3868:    Logically Collective on SNES

3870:    Input Parameters:
3871: .  snes - the SNES context

3873:    Options Database Key:
3874: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
3875:     into a code by calls to SNESMonitorSet(), but does not cancel those
3876:     set via the options database

3878:    Notes:
3879:    There is no way to clear one specific monitor from a SNES object.

3881:    Level: intermediate

3883: .seealso: SNESMonitorDefault(), SNESMonitorSet()
3884: @*/
3885: PetscErrorCode  SNESMonitorCancel(SNES snes)
3886: {
3888:   PetscInt       i;

3892:   for (i=0; i<snes->numbermonitors; i++) {
3893:     if (snes->monitordestroy[i]) {
3894:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
3895:     }
3896:   }
3897:   snes->numbermonitors = 0;
3898:   return(0);
3899: }

3901: /*MC
3902:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

3904:      Synopsis:
3905:      #include <petscsnes.h>
3906: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

3908: +    snes - the SNES context
3909: .    it - current iteration (0 is the first and is before any Newton step)
3910: .    cctx - [optional] convergence context
3911: .    reason - reason for convergence/divergence
3912: .    xnorm - 2-norm of current iterate
3913: .    gnorm - 2-norm of current step
3914: -    f - 2-norm of function

3916:    Level: intermediate

3918: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
3919: M*/

3921: /*@C
3922:    SNESSetConvergenceTest - Sets the function that is to be used
3923:    to test for convergence of the nonlinear iterative solution.

3925:    Logically Collective on SNES

3927:    Input Parameters:
3928: +  snes - the SNES context
3929: .  SNESConvergenceTestFunction - routine to test for convergence
3930: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
3931: -  destroy - [optional] destructor for the context (may be NULL; PETSC_NULL_FUNCTION in Fortran)

3933:    Level: advanced

3935: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
3936: @*/
3937: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
3938: {

3943:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
3944:   if (snes->ops->convergeddestroy) {
3945:     (*snes->ops->convergeddestroy)(snes->cnvP);
3946:   }
3947:   snes->ops->converged        = SNESConvergenceTestFunction;
3948:   snes->ops->convergeddestroy = destroy;
3949:   snes->cnvP                  = cctx;
3950:   return(0);
3951: }

3953: /*@
3954:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

3956:    Not Collective

3958:    Input Parameter:
3959: .  snes - the SNES context

3961:    Output Parameter:
3962: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3963:             manual pages for the individual convergence tests for complete lists

3965:    Options Database:
3966: .   -snes_converged_reason - prints the reason to standard out

3968:    Level: intermediate

3970:    Notes:
3971:     Should only be called after the call the SNESSolve() is complete, if it is called earlier it returns the value SNES__CONVERGED_ITERATING.

3973: .seealso: SNESSetConvergenceTest(), SNESSetConvergedReason(), SNESConvergedReason
3974: @*/
3975: PetscErrorCode SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
3976: {
3980:   *reason = snes->reason;
3981:   return(0);
3982: }

3984: /*@
3985:    SNESSetConvergedReason - Sets the reason the SNES iteration was stopped.

3987:    Not Collective

3989:    Input Parameters:
3990: +  snes - the SNES context
3991: -  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3992:             manual pages for the individual convergence tests for complete lists

3994:    Level: intermediate

3996: .seealso: SNESGetConvergedReason(), SNESSetConvergenceTest(), SNESConvergedReason
3997: @*/
3998: PetscErrorCode SNESSetConvergedReason(SNES snes,SNESConvergedReason reason)
3999: {
4002:   snes->reason = reason;
4003:   return(0);
4004: }

4006: /*@
4007:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

4009:    Logically Collective on SNES

4011:    Input Parameters:
4012: +  snes - iterative context obtained from SNESCreate()
4013: .  a   - array to hold history, this array will contain the function norms computed at each step
4014: .  its - integer array holds the number of linear iterations for each solve.
4015: .  na  - size of a and its
4016: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
4017:            else it continues storing new values for new nonlinear solves after the old ones

4019:    Notes:
4020:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
4021:    default array of length 10000 is allocated.

4023:    This routine is useful, e.g., when running a code for purposes
4024:    of accurate performance monitoring, when no I/O should be done
4025:    during the section of code that is being timed.

4027:    Level: intermediate

4029: .seealso: SNESGetConvergenceHistory()

4031: @*/
4032: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
4033: {

4040:   if (!a) {
4041:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
4042:     PetscCalloc2(na,&a,na,&its);
4043:     snes->conv_hist_alloc = PETSC_TRUE;
4044:   }
4045:   snes->conv_hist       = a;
4046:   snes->conv_hist_its   = its;
4047:   snes->conv_hist_max   = na;
4048:   snes->conv_hist_len   = 0;
4049:   snes->conv_hist_reset = reset;
4050:   return(0);
4051: }

4053: #if defined(PETSC_HAVE_MATLAB_ENGINE)
4054: #include <engine.h>   /* MATLAB include file */
4055: #include <mex.h>      /* MATLAB include file */

4057: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
4058: {
4059:   mxArray   *mat;
4060:   PetscInt  i;
4061:   PetscReal *ar;

4064:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
4065:   ar  = (PetscReal*) mxGetData(mat);
4066:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
4067:   PetscFunctionReturn(mat);
4068: }
4069: #endif

4071: /*@C
4072:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

4074:    Not Collective

4076:    Input Parameter:
4077: .  snes - iterative context obtained from SNESCreate()

4079:    Output Parameters:
4080: .  a   - array to hold history
4081: .  its - integer array holds the number of linear iterations (or
4082:          negative if not converged) for each solve.
4083: -  na  - size of a and its

4085:    Notes:
4086:     The calling sequence for this routine in Fortran is
4087: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

4089:    This routine is useful, e.g., when running a code for purposes
4090:    of accurate performance monitoring, when no I/O should be done
4091:    during the section of code that is being timed.

4093:    Level: intermediate

4095: .seealso: SNESSetConvergencHistory()

4097: @*/
4098: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
4099: {
4102:   if (a)   *a   = snes->conv_hist;
4103:   if (its) *its = snes->conv_hist_its;
4104:   if (na)  *na  = snes->conv_hist_len;
4105:   return(0);
4106: }

4108: /*@C
4109:   SNESSetUpdate - Sets the general-purpose update function called
4110:   at the beginning of every iteration of the nonlinear solve. Specifically
4111:   it is called just before the Jacobian is "evaluated".

4113:   Logically Collective on SNES

4115:   Input Parameters:
4116: . snes - The nonlinear solver context
4117: . func - The function

4119:   Calling sequence of func:
4120: . func (SNES snes, PetscInt step);

4122: . step - The current step of the iteration

4124:   Level: advanced

4126:   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()
4127:         This is not used by most users.

4129: .seealso SNESSetJacobian(), SNESSolve()
4130: @*/
4131: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
4132: {
4135:   snes->ops->update = func;
4136:   return(0);
4137: }

4139: /*
4140:    SNESScaleStep_Private - Scales a step so that its length is less than the
4141:    positive parameter delta.

4143:     Input Parameters:
4144: +   snes - the SNES context
4145: .   y - approximate solution of linear system
4146: .   fnorm - 2-norm of current function
4147: -   delta - trust region size

4149:     Output Parameters:
4150: +   gpnorm - predicted function norm at the new point, assuming local
4151:     linearization.  The value is zero if the step lies within the trust
4152:     region, and exceeds zero otherwise.
4153: -   ynorm - 2-norm of the step

4155:     Note:
4156:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
4157:     is set to be the maximum allowable step size.

4159: */
4160: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
4161: {
4162:   PetscReal      nrm;
4163:   PetscScalar    cnorm;


4171:   VecNorm(y,NORM_2,&nrm);
4172:   if (nrm > *delta) {
4173:     nrm     = *delta/nrm;
4174:     *gpnorm = (1.0 - nrm)*(*fnorm);
4175:     cnorm   = nrm;
4176:     VecScale(y,cnorm);
4177:     *ynorm  = *delta;
4178:   } else {
4179:     *gpnorm = 0.0;
4180:     *ynorm  = nrm;
4181:   }
4182:   return(0);
4183: }

4185: /*@
4186:    SNESReasonView - Displays the reason a SNES solve converged or diverged to a viewer

4188:    Collective on SNES

4190:    Parameter:
4191: +  snes - iterative context obtained from SNESCreate()
4192: -  viewer - the viewer to display the reason


4195:    Options Database Keys:
4196: .  -snes_converged_reason - print reason for converged or diverged, also prints number of iterations

4198:    Level: beginner

4200: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault()

4202: @*/
4203: PetscErrorCode  SNESReasonView(SNES snes,PetscViewer viewer)
4204: {
4205:   PetscViewerFormat format;
4206:   PetscBool         isAscii;
4207:   PetscErrorCode    ierr;

4210:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isAscii);
4211:   if (isAscii) {
4212:     PetscViewerGetFormat(viewer, &format);
4213:     PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);
4214:     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4215:       DM                dm;
4216:       Vec               u;
4217:       PetscDS           prob;
4218:       PetscInt          Nf, f;
4219:       PetscErrorCode (**exactSol)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4220:       void            **exactCtx;
4221:       PetscReal         error;

4223:       SNESGetDM(snes, &dm);
4224:       SNESGetSolution(snes, &u);
4225:       DMGetDS(dm, &prob);
4226:       PetscDSGetNumFields(prob, &Nf);
4227:       PetscMalloc2(Nf, &exactSol, Nf, &exactCtx);
4228:       for (f = 0; f < Nf; ++f) {PetscDSGetExactSolution(prob, f, &exactSol[f], &exactCtx[f]);}
4229:       DMComputeL2Diff(dm, 0.0, exactSol, exactCtx, u, &error);
4230:       PetscFree2(exactSol, exactCtx);
4231:       if (error < 1.0e-11) {PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n");}
4232:       else                 {PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", error);}
4233:     }
4234:     if (snes->reason > 0) {
4235:       if (((PetscObject) snes)->prefix) {
4236:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve converged due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4237:       } else {
4238:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4239:       }
4240:     } else {
4241:       if (((PetscObject) snes)->prefix) {
4242:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve did not converge due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4243:       } else {
4244:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4245:       }
4246:     }
4247:     PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);
4248:   }
4249:   return(0);
4250: }

4252: /*@C
4253:   SNESReasonViewFromOptions - Processes command line options to determine if/how a SNESReason is to be viewed.

4255:   Collective on SNES

4257:   Input Parameters:
4258: . snes   - the SNES object

4260:   Level: intermediate

4262: @*/
4263: PetscErrorCode SNESReasonViewFromOptions(SNES snes)
4264: {
4265:   PetscErrorCode    ierr;
4266:   PetscViewer       viewer;
4267:   PetscBool         flg;
4268:   static PetscBool  incall = PETSC_FALSE;
4269:   PetscViewerFormat format;

4272:   if (incall) return(0);
4273:   incall = PETSC_TRUE;
4274:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_converged_reason",&viewer,&format,&flg);
4275:   if (flg) {
4276:     PetscViewerPushFormat(viewer,format);
4277:     SNESReasonView(snes,viewer);
4278:     PetscViewerPopFormat(viewer);
4279:     PetscViewerDestroy(&viewer);
4280:   }
4281:   incall = PETSC_FALSE;
4282:   return(0);
4283: }

4285: /*@
4286:    SNESSolve - Solves a nonlinear system F(x) = b.
4287:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

4289:    Collective on SNES

4291:    Input Parameters:
4292: +  snes - the SNES context
4293: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
4294: -  x - the solution vector.

4296:    Notes:
4297:    The user should initialize the vector,x, with the initial guess
4298:    for the nonlinear solve prior to calling SNESSolve.  In particular,
4299:    to employ an initial guess of zero, the user should explicitly set
4300:    this vector to zero by calling VecSet().

4302:    Level: beginner

4304: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
4305: @*/
4306: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
4307: {
4308:   PetscErrorCode    ierr;
4309:   PetscBool         flg;
4310:   PetscInt          grid;
4311:   Vec               xcreated = NULL;
4312:   DM                dm;


4321:   /* High level operations using the nonlinear solver */
4322:   {
4323:     PetscViewer       viewer;
4324:     PetscViewerFormat format;
4325:     PetscInt          num;
4326:     PetscBool         flg;
4327:     static PetscBool  incall = PETSC_FALSE;

4329:     if (!incall) {
4330:       /* Estimate the convergence rate of the discretization */
4331:       PetscOptionsGetViewer(PetscObjectComm((PetscObject) snes),((PetscObject)snes)->options, ((PetscObject) snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg);
4332:       if (flg) {
4333:         PetscConvEst conv;
4334:         DM           dm;
4335:         PetscReal   *alpha; /* Convergence rate of the solution error for each field in the L_2 norm */
4336:         PetscInt     Nf;

4338:         incall = PETSC_TRUE;
4339:         SNESGetDM(snes, &dm);
4340:         DMGetNumFields(dm, &Nf);
4341:         PetscCalloc1(Nf, &alpha);
4342:         PetscConvEstCreate(PetscObjectComm((PetscObject) snes), &conv);
4343:         PetscConvEstSetSolver(conv, snes);
4344:         PetscConvEstSetFromOptions(conv);
4345:         PetscConvEstSetUp(conv);
4346:         PetscConvEstGetConvRate(conv, alpha);
4347:         PetscViewerPushFormat(viewer, format);
4348:         PetscConvEstRateView(conv, alpha, viewer);
4349:         PetscViewerPopFormat(viewer);
4350:         PetscViewerDestroy(&viewer);
4351:         PetscConvEstDestroy(&conv);
4352:         PetscFree(alpha);
4353:         incall = PETSC_FALSE;
4354:       }
4355:       /* Adaptively refine the initial grid */
4356:       num  = 1;
4357:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_initial", &num, &flg);
4358:       if (flg) {
4359:         DMAdaptor adaptor;

4361:         incall = PETSC_TRUE;
4362:         DMAdaptorCreate(PETSC_COMM_WORLD, &adaptor);
4363:         DMAdaptorSetSolver(adaptor, snes);
4364:         DMAdaptorSetSequenceLength(adaptor, num);
4365:         DMAdaptorSetFromOptions(adaptor);
4366:         DMAdaptorSetUp(adaptor);
4367:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x);
4368:         DMAdaptorDestroy(&adaptor);
4369:         incall = PETSC_FALSE;
4370:       }
4371:       /* Use grid sequencing to adapt */
4372:       num  = 0;
4373:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_sequence", &num, NULL);
4374:       if (num) {
4375:         DMAdaptor adaptor;

4377:         incall = PETSC_TRUE;
4378:         DMAdaptorCreate(PETSC_COMM_WORLD, &adaptor);
4379:         DMAdaptorSetSolver(adaptor, snes);
4380:         DMAdaptorSetSequenceLength(adaptor, num);
4381:         DMAdaptorSetFromOptions(adaptor);
4382:         DMAdaptorSetUp(adaptor);
4383:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x);
4384:         DMAdaptorDestroy(&adaptor);
4385:         incall = PETSC_FALSE;
4386:       }
4387:     }
4388:   }
4389:   if (!x) {
4390:     SNESGetDM(snes,&dm);
4391:     DMCreateGlobalVector(dm,&xcreated);
4392:     x    = xcreated;
4393:   }
4394:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

4396:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
4397:   for (grid=0; grid<snes->gridsequence+1; grid++) {

4399:     /* set solution vector */
4400:     if (!grid) {PetscObjectReference((PetscObject)x);}
4401:     VecDestroy(&snes->vec_sol);
4402:     snes->vec_sol = x;
4403:     SNESGetDM(snes,&dm);

4405:     /* set affine vector if provided */
4406:     if (b) { PetscObjectReference((PetscObject)b); }
4407:     VecDestroy(&snes->vec_rhs);
4408:     snes->vec_rhs = b;

4410:     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");
4411:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
4412:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
4413:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
4414:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
4415:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
4416:     }
4417:     DMShellSetGlobalVector(dm,snes->vec_sol);
4418:     SNESSetUp(snes);

4420:     if (!grid) {
4421:       if (snes->ops->computeinitialguess) {
4422:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
4423:       }
4424:     }

4426:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4427:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

4429:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
4430:     (*snes->ops->solve)(snes);
4431:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
4432:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");
4433:     snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */

4435:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4436:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

4438:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_test_local_min",NULL,NULL,&flg);
4439:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
4440:     SNESReasonViewFromOptions(snes);

4442:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
4443:     if (snes->reason < 0) break;
4444:     if (grid <  snes->gridsequence) {
4445:       DM  fine;
4446:       Vec xnew;
4447:       Mat interp;

4449:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
4450:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
4451:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
4452:       DMCreateGlobalVector(fine,&xnew);
4453:       MatInterpolate(interp,x,xnew);
4454:       DMInterpolate(snes->dm,interp,fine);
4455:       MatDestroy(&interp);
4456:       x    = xnew;

4458:       SNESReset(snes);
4459:       SNESSetDM(snes,fine);
4460:       SNESResetFromOptions(snes);
4461:       DMDestroy(&fine);
4462:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
4463:     }
4464:   }
4465:   SNESViewFromOptions(snes,NULL,"-snes_view");
4466:   VecViewFromOptions(snes->vec_sol,(PetscObject)snes,"-snes_view_solution");

4468:   VecDestroy(&xcreated);
4469:   PetscObjectSAWsBlock((PetscObject)snes);
4470:   return(0);
4471: }

4473: /* --------- Internal routines for SNES Package --------- */

4475: /*@C
4476:    SNESSetType - Sets the method for the nonlinear solver.

4478:    Collective on SNES

4480:    Input Parameters:
4481: +  snes - the SNES context
4482: -  type - a known method

4484:    Options Database Key:
4485: .  -snes_type <type> - Sets the method; use -help for a list
4486:    of available methods (for instance, newtonls or newtontr)

4488:    Notes:
4489:    See "petsc/include/petscsnes.h" for available methods (for instance)
4490: +    SNESNEWTONLS - Newton's method with line search
4491:      (systems of nonlinear equations)
4492: .    SNESNEWTONTR - Newton's method with trust region
4493:      (systems of nonlinear equations)

4495:   Normally, it is best to use the SNESSetFromOptions() command and then
4496:   set the SNES solver type from the options database rather than by using
4497:   this routine.  Using the options database provides the user with
4498:   maximum flexibility in evaluating the many nonlinear solvers.
4499:   The SNESSetType() routine is provided for those situations where it
4500:   is necessary to set the nonlinear solver independently of the command
4501:   line or options database.  This might be the case, for example, when
4502:   the choice of solver changes during the execution of the program,
4503:   and the user's application is taking responsibility for choosing the
4504:   appropriate method.

4506:     Developer Notes:
4507:     SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
4508:     the constructor in that list and calls it to create the spexific object.

4510:   Level: intermediate

4512: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

4514: @*/
4515: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
4516: {
4517:   PetscErrorCode ierr,(*r)(SNES);
4518:   PetscBool      match;


4524:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
4525:   if (match) return(0);

4527:    PetscFunctionListFind(SNESList,type,&r);
4528:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
4529:   /* Destroy the previous private SNES context */
4530:   if (snes->ops->destroy) {
4531:     (*(snes)->ops->destroy)(snes);
4532:     snes->ops->destroy = NULL;
4533:   }
4534:   /* Reinitialize function pointers in SNESOps structure */
4535:   snes->ops->setup          = 0;
4536:   snes->ops->solve          = 0;
4537:   snes->ops->view           = 0;
4538:   snes->ops->setfromoptions = 0;
4539:   snes->ops->destroy        = 0;
4540:   SNESLineSearchDestroy(&snes->linesearch);
4541:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4542:   snes->setupcalled = PETSC_FALSE;

4544:   PetscObjectChangeTypeName((PetscObject)snes,type);
4545:   (*r)(snes);
4546:   return(0);
4547: }

4549: /*@C
4550:    SNESGetType - Gets the SNES method type and name (as a string).

4552:    Not Collective

4554:    Input Parameter:
4555: .  snes - nonlinear solver context

4557:    Output Parameter:
4558: .  type - SNES method (a character string)

4560:    Level: intermediate

4562: @*/
4563: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
4564: {
4568:   *type = ((PetscObject)snes)->type_name;
4569:   return(0);
4570: }

4572: /*@
4573:   SNESSetSolution - Sets the solution vector for use by the SNES routines.

4575:   Logically Collective on SNES

4577:   Input Parameters:
4578: + snes - the SNES context obtained from SNESCreate()
4579: - u    - the solution vector

4581:   Level: beginner

4583: @*/
4584: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4585: {
4586:   DM             dm;

4592:   PetscObjectReference((PetscObject) u);
4593:   VecDestroy(&snes->vec_sol);

4595:   snes->vec_sol = u;

4597:   SNESGetDM(snes, &dm);
4598:   DMShellSetGlobalVector(dm, u);
4599:   return(0);
4600: }

4602: /*@
4603:    SNESGetSolution - Returns the vector where the approximate solution is
4604:    stored. This is the fine grid solution when using SNESSetGridSequence().

4606:    Not Collective, but Vec is parallel if SNES is parallel

4608:    Input Parameter:
4609: .  snes - the SNES context

4611:    Output Parameter:
4612: .  x - the solution

4614:    Level: intermediate

4616: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
4617: @*/
4618: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
4619: {
4623:   *x = snes->vec_sol;
4624:   return(0);
4625: }

4627: /*@
4628:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4629:    stored.

4631:    Not Collective, but Vec is parallel if SNES is parallel

4633:    Input Parameter:
4634: .  snes - the SNES context

4636:    Output Parameter:
4637: .  x - the solution update

4639:    Level: advanced

4641: .seealso: SNESGetSolution(), SNESGetFunction()
4642: @*/
4643: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4644: {
4648:   *x = snes->vec_sol_update;
4649:   return(0);
4650: }

4652: /*@C
4653:    SNESGetFunction - Returns the vector where the function is stored.

4655:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4657:    Input Parameter:
4658: .  snes - the SNES context

4660:    Output Parameter:
4661: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4662: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4663: -  ctx - the function context (or NULL if you don't want it)

4665:    Level: advanced

4667:     Notes: The vector r DOES NOT, in general contain the current value of the SNES nonlinear function

4669: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4670: @*/
4671: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4672: {
4674:   DM             dm;

4678:   if (r) {
4679:     if (!snes->vec_func) {
4680:       if (snes->vec_rhs) {
4681:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4682:       } else if (snes->vec_sol) {
4683:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4684:       } else if (snes->dm) {
4685:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4686:       }
4687:     }
4688:     *r = snes->vec_func;
4689:   }
4690:   SNESGetDM(snes,&dm);
4691:   DMSNESGetFunction(dm,f,ctx);
4692:   return(0);
4693: }

4695: /*@C
4696:    SNESGetNGS - Returns the NGS function and context.

4698:    Input Parameter:
4699: .  snes - the SNES context

4701:    Output Parameter:
4702: +  f - the function (or NULL) see SNESNGSFunction for details
4703: -  ctx    - the function context (or NULL)

4705:    Level: advanced

4707: .seealso: SNESSetNGS(), SNESGetFunction()
4708: @*/

4710: PetscErrorCode SNESGetNGS (SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void*), void ** ctx)
4711: {
4713:   DM             dm;

4717:   SNESGetDM(snes,&dm);
4718:   DMSNESGetNGS(dm,f,ctx);
4719:   return(0);
4720: }

4722: /*@C
4723:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4724:    SNES options in the database.

4726:    Logically Collective on SNES

4728:    Input Parameter:
4729: +  snes - the SNES context
4730: -  prefix - the prefix to prepend to all option names

4732:    Notes:
4733:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4734:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4736:    Level: advanced

4738: .seealso: SNESSetFromOptions()
4739: @*/
4740: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4741: {

4746:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4747:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4748:   if (snes->linesearch) {
4749:     SNESGetLineSearch(snes,&snes->linesearch);
4750:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4751:   }
4752:   KSPSetOptionsPrefix(snes->ksp,prefix);
4753:   return(0);
4754: }

4756: /*@C
4757:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4758:    SNES options in the database.

4760:    Logically Collective on SNES

4762:    Input Parameters:
4763: +  snes - the SNES context
4764: -  prefix - the prefix to prepend to all option names

4766:    Notes:
4767:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4768:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4770:    Level: advanced

4772: .seealso: SNESGetOptionsPrefix()
4773: @*/
4774: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
4775: {

4780:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
4781:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4782:   if (snes->linesearch) {
4783:     SNESGetLineSearch(snes,&snes->linesearch);
4784:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
4785:   }
4786:   KSPAppendOptionsPrefix(snes->ksp,prefix);
4787:   return(0);
4788: }

4790: /*@C
4791:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
4792:    SNES options in the database.

4794:    Not Collective

4796:    Input Parameter:
4797: .  snes - the SNES context

4799:    Output Parameter:
4800: .  prefix - pointer to the prefix string used

4802:    Notes:
4803:     On the fortran side, the user should pass in a string 'prefix' of
4804:    sufficient length to hold the prefix.

4806:    Level: advanced

4808: .seealso: SNESAppendOptionsPrefix()
4809: @*/
4810: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
4811: {

4816:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
4817:   return(0);
4818: }


4821: /*@C
4822:   SNESRegister - Adds a method to the nonlinear solver package.

4824:    Not collective

4826:    Input Parameters:
4827: +  name_solver - name of a new user-defined solver
4828: -  routine_create - routine to create method context

4830:    Notes:
4831:    SNESRegister() may be called multiple times to add several user-defined solvers.

4833:    Sample usage:
4834: .vb
4835:    SNESRegister("my_solver",MySolverCreate);
4836: .ve

4838:    Then, your solver can be chosen with the procedural interface via
4839: $     SNESSetType(snes,"my_solver")
4840:    or at runtime via the option
4841: $     -snes_type my_solver

4843:    Level: advanced

4845:     Note: If your function is not being put into a shared library then use SNESRegister() instead

4847: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

4849:   Level: advanced
4850: @*/
4851: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
4852: {

4856:   SNESInitializePackage();
4857:   PetscFunctionListAdd(&SNESList,sname,function);
4858:   return(0);
4859: }

4861: PetscErrorCode  SNESTestLocalMin(SNES snes)
4862: {
4864:   PetscInt       N,i,j;
4865:   Vec            u,uh,fh;
4866:   PetscScalar    value;
4867:   PetscReal      norm;

4870:   SNESGetSolution(snes,&u);
4871:   VecDuplicate(u,&uh);
4872:   VecDuplicate(u,&fh);

4874:   /* currently only works for sequential */
4875:   PetscPrintf(PETSC_COMM_WORLD,"Testing FormFunction() for local min\n");
4876:   VecGetSize(u,&N);
4877:   for (i=0; i<N; i++) {
4878:     VecCopy(u,uh);
4879:     PetscPrintf(PETSC_COMM_WORLD,"i = %D\n",i);
4880:     for (j=-10; j<11; j++) {
4881:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
4882:       VecSetValue(uh,i,value,ADD_VALUES);
4883:       SNESComputeFunction(snes,uh,fh);
4884:       VecNorm(fh,NORM_2,&norm);
4885:       PetscPrintf(PETSC_COMM_WORLD,"       j norm %D %18.16e\n",j,norm);
4886:       value = -value;
4887:       VecSetValue(uh,i,value,ADD_VALUES);
4888:     }
4889:   }
4890:   VecDestroy(&uh);
4891:   VecDestroy(&fh);
4892:   return(0);
4893: }

4895: /*@
4896:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
4897:    computing relative tolerance for linear solvers within an inexact
4898:    Newton method.

4900:    Logically Collective on SNES

4902:    Input Parameters:
4903: +  snes - SNES context
4904: -  flag - PETSC_TRUE or PETSC_FALSE

4906:     Options Database:
4907: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
4908: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
4909: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
4910: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
4911: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
4912: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
4913: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
4914: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

4916:    Notes:
4917:    Currently, the default is to use a constant relative tolerance for
4918:    the inner linear solvers.  Alternatively, one can use the
4919:    Eisenstat-Walker method, where the relative convergence tolerance
4920:    is reset at each Newton iteration according progress of the nonlinear
4921:    solver.

4923:    Level: advanced

4925:    Reference:
4926:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4927:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4929: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4930: @*/
4931: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
4932: {
4936:   snes->ksp_ewconv = flag;
4937:   return(0);
4938: }

4940: /*@
4941:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
4942:    for computing relative tolerance for linear solvers within an
4943:    inexact Newton method.

4945:    Not Collective

4947:    Input Parameter:
4948: .  snes - SNES context

4950:    Output Parameter:
4951: .  flag - PETSC_TRUE or PETSC_FALSE

4953:    Notes:
4954:    Currently, the default is to use a constant relative tolerance for
4955:    the inner linear solvers.  Alternatively, one can use the
4956:    Eisenstat-Walker method, where the relative convergence tolerance
4957:    is reset at each Newton iteration according progress of the nonlinear
4958:    solver.

4960:    Level: advanced

4962:    Reference:
4963:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4964:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4966: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4967: @*/
4968: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
4969: {
4973:   *flag = snes->ksp_ewconv;
4974:   return(0);
4975: }

4977: /*@
4978:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
4979:    convergence criteria for the linear solvers within an inexact
4980:    Newton method.

4982:    Logically Collective on SNES

4984:    Input Parameters:
4985: +    snes - SNES context
4986: .    version - version 1, 2 (default is 2) or 3
4987: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4988: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4989: .    gamma - multiplicative factor for version 2 rtol computation
4990:              (0 <= gamma2 <= 1)
4991: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4992: .    alpha2 - power for safeguard
4993: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4995:    Note:
4996:    Version 3 was contributed by Luis Chacon, June 2006.

4998:    Use PETSC_DEFAULT to retain the default for any of the parameters.

5000:    Level: advanced

5002:    Reference:
5003:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
5004:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
5005:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

5007: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
5008: @*/
5009: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
5010: {
5011:   SNESKSPEW *kctx;

5015:   kctx = (SNESKSPEW*)snes->kspconvctx;
5016:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

5025:   if (version != PETSC_DEFAULT)   kctx->version   = version;
5026:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
5027:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
5028:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
5029:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
5030:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
5031:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

5033:   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);
5034:   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);
5035:   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);
5036:   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);
5037:   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);
5038:   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);
5039:   return(0);
5040: }

5042: /*@
5043:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
5044:    convergence criteria for the linear solvers within an inexact
5045:    Newton method.

5047:    Not Collective

5049:    Input Parameters:
5050:      snes - SNES context

5052:    Output Parameters:
5053: +    version - version 1, 2 (default is 2) or 3
5054: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
5055: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
5056: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
5057: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
5058: .    alpha2 - power for safeguard
5059: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

5061:    Level: advanced

5063: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
5064: @*/
5065: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
5066: {
5067:   SNESKSPEW *kctx;

5071:   kctx = (SNESKSPEW*)snes->kspconvctx;
5072:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
5073:   if (version)   *version   = kctx->version;
5074:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
5075:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
5076:   if (gamma)     *gamma     = kctx->gamma;
5077:   if (alpha)     *alpha     = kctx->alpha;
5078:   if (alpha2)    *alpha2    = kctx->alpha2;
5079:   if (threshold) *threshold = kctx->threshold;
5080:   return(0);
5081: }

5083:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5084: {
5086:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5087:   PetscReal      rtol  = PETSC_DEFAULT,stol;

5090:   if (!snes->ksp_ewconv) return(0);
5091:   if (!snes->iter) {
5092:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
5093:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
5094:   }
5095:   else {
5096:     if (kctx->version == 1) {
5097:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
5098:       if (rtol < 0.0) rtol = -rtol;
5099:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
5100:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5101:     } else if (kctx->version == 2) {
5102:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5103:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
5104:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5105:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5106:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5107:       /* safeguard: avoid sharp decrease of rtol */
5108:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
5109:       stol = PetscMax(rtol,stol);
5110:       rtol = PetscMin(kctx->rtol_0,stol);
5111:       /* safeguard: avoid oversolving */
5112:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
5113:       stol = PetscMax(rtol,stol);
5114:       rtol = PetscMin(kctx->rtol_0,stol);
5115:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
5116:   }
5117:   /* safeguard: avoid rtol greater than one */
5118:   rtol = PetscMin(rtol,kctx->rtol_max);
5119:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
5120:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
5121:   return(0);
5122: }

5124: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5125: {
5127:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5128:   PCSide         pcside;
5129:   Vec            lres;

5132:   if (!snes->ksp_ewconv) return(0);
5133:   KSPGetTolerances(ksp,&kctx->rtol_last,0,0,0);
5134:   kctx->norm_last = snes->norm;
5135:   if (kctx->version == 1) {
5136:     PC        pc;
5137:     PetscBool isNone;

5139:     KSPGetPC(ksp, &pc);
5140:     PetscObjectTypeCompare((PetscObject) pc, PCNONE, &isNone);
5141:     KSPGetPCSide(ksp,&pcside);
5142:      if (pcside == PC_RIGHT || isNone) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
5143:       /* KSP residual is true linear residual */
5144:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
5145:     } else {
5146:       /* KSP residual is preconditioned residual */
5147:       /* compute true linear residual norm */
5148:       VecDuplicate(b,&lres);
5149:       MatMult(snes->jacobian,x,lres);
5150:       VecAYPX(lres,-1.0,b);
5151:       VecNorm(lres,NORM_2,&kctx->lresid_last);
5152:       VecDestroy(&lres);
5153:     }
5154:   }
5155:   return(0);
5156: }

5158: /*@
5159:    SNESGetKSP - Returns the KSP context for a SNES solver.

5161:    Not Collective, but if SNES object is parallel, then KSP object is parallel

5163:    Input Parameter:
5164: .  snes - the SNES context

5166:    Output Parameter:
5167: .  ksp - the KSP context

5169:    Notes:
5170:    The user can then directly manipulate the KSP context to set various
5171:    options, etc.  Likewise, the user can then extract and manipulate the
5172:    PC contexts as well.

5174:    Level: beginner

5176: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
5177: @*/
5178: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
5179: {


5186:   if (!snes->ksp) {
5187:     PetscBool monitor = PETSC_FALSE;

5189:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
5190:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
5191:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

5193:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
5194:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);

5196:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes",&monitor,NULL);
5197:     if (monitor) {
5198:       KSPMonitorSet(snes->ksp,KSPMonitorSNES,snes,NULL);
5199:     }
5200:     monitor = PETSC_FALSE;
5201:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes_lg",&monitor,NULL);
5202:     if (monitor) {
5203:       PetscObject *objs;
5204:       KSPMonitorSNESLGResidualNormCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,600,600,&objs);
5205:       objs[0] = (PetscObject) snes;
5206:       KSPMonitorSet(snes->ksp,(PetscErrorCode (*)(KSP,PetscInt,PetscReal,void*))KSPMonitorSNESLGResidualNorm,objs,(PetscErrorCode (*)(void**))KSPMonitorSNESLGResidualNormDestroy);
5207:     }
5208:     PetscObjectSetOptions((PetscObject)snes->ksp,((PetscObject)snes)->options);
5209:   }
5210:   *ksp = snes->ksp;
5211:   return(0);
5212: }


5215:  #include <petsc/private/dmimpl.h>
5216: /*@
5217:    SNESSetDM - Sets the DM that may be used by some nonlinear solvers or their underlying preconditioners

5219:    Logically Collective on SNES

5221:    Input Parameters:
5222: +  snes - the nonlinear solver context
5223: -  dm - the dm, cannot be NULL

5225:    Notes:
5226:    A DM can only be used for solving one problem at a time because information about the problem is stored on the DM,
5227:    even when not using interfaces like DMSNESSetFunction().  Use DMClone() to get a distinct DM when solving different
5228:    problems using the same function space.

5230:    Level: intermediate

5232: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
5233: @*/
5234: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
5235: {
5237:   KSP            ksp;
5238:   DMSNES         sdm;

5243:   PetscObjectReference((PetscObject)dm);
5244:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
5245:     if (snes->dm->dmsnes && !dm->dmsnes) {
5246:       DMCopyDMSNES(snes->dm,dm);
5247:       DMGetDMSNES(snes->dm,&sdm);
5248:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5249:     }
5250:     DMCoarsenHookRemove(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
5251:     DMDestroy(&snes->dm);
5252:   }
5253:   snes->dm     = dm;
5254:   snes->dmAuto = PETSC_FALSE;

5256:   SNESGetKSP(snes,&ksp);
5257:   KSPSetDM(ksp,dm);
5258:   KSPSetDMActive(ksp,PETSC_FALSE);
5259:   if (snes->npc) {
5260:     SNESSetDM(snes->npc, snes->dm);
5261:     SNESSetNPCSide(snes,snes->npcside);
5262:   }
5263:   return(0);
5264: }

5266: /*@
5267:    SNESGetDM - Gets the DM that may be used by some preconditioners

5269:    Not Collective but DM obtained is parallel on SNES

5271:    Input Parameter:
5272: . snes - the preconditioner context

5274:    Output Parameter:
5275: .  dm - the dm

5277:    Level: intermediate

5279: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
5280: @*/
5281: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
5282: {

5287:   if (!snes->dm) {
5288:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
5289:     snes->dmAuto = PETSC_TRUE;
5290:   }
5291:   *dm = snes->dm;
5292:   return(0);
5293: }

5295: /*@
5296:   SNESSetNPC - Sets the nonlinear preconditioner to be used.

5298:   Collective on SNES

5300:   Input Parameters:
5301: + snes - iterative context obtained from SNESCreate()
5302: - pc   - the preconditioner object

5304:   Notes:
5305:   Use SNESGetNPC() to retrieve the preconditioner context (for example,
5306:   to configure it using the API).

5308:   Level: developer

5310: .seealso: SNESGetNPC(), SNESHasNPC()
5311: @*/
5312: PetscErrorCode SNESSetNPC(SNES snes, SNES pc)
5313: {

5320:   PetscObjectReference((PetscObject) pc);
5321:   SNESDestroy(&snes->npc);
5322:   snes->npc = pc;
5323:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->npc);
5324:   return(0);
5325: }

5327: /*@
5328:   SNESGetNPC - Creates a nonlinear preconditioning solver (SNES) to be used to precondition the nonlinear solver.

5330:   Not Collective; but any changes to the obtained SNES object must be applied collectively

5332:   Input Parameter:
5333: . snes - iterative context obtained from SNESCreate()

5335:   Output Parameter:
5336: . pc - preconditioner context

5338:   Notes:
5339:     If a SNES was previously set with SNESSetNPC() then that SNES is returned.

5341:     The (preconditioner) SNES returned automatically inherits the same nonlinear function and Jacobian supplied to the original
5342:     SNES during SNESSetUp()

5344:   Level: developer

5346: .seealso: SNESSetNPC(), SNESHasNPC(), SNES, SNESCreate()
5347: @*/
5348: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5349: {
5351:   const char     *optionsprefix;

5356:   if (!snes->npc) {
5357:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->npc);
5358:     PetscObjectIncrementTabLevel((PetscObject)snes->npc,(PetscObject)snes,1);
5359:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->npc);
5360:     SNESGetOptionsPrefix(snes,&optionsprefix);
5361:     SNESSetOptionsPrefix(snes->npc,optionsprefix);
5362:     SNESAppendOptionsPrefix(snes->npc,"npc_");
5363:     SNESSetCountersReset(snes->npc,PETSC_FALSE);
5364:   }
5365:   *pc = snes->npc;
5366:   return(0);
5367: }

5369: /*@
5370:   SNESHasNPC - Returns whether a nonlinear preconditioner exists

5372:   Not Collective

5374:   Input Parameter:
5375: . snes - iterative context obtained from SNESCreate()

5377:   Output Parameter:
5378: . has_npc - whether the SNES has an NPC or not

5380:   Level: developer

5382: .seealso: SNESSetNPC(), SNESGetNPC()
5383: @*/
5384: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5385: {
5388:   *has_npc = (PetscBool) (snes->npc ? PETSC_TRUE : PETSC_FALSE);
5389:   return(0);
5390: }

5392: /*@
5393:     SNESSetNPCSide - Sets the preconditioning side.

5395:     Logically Collective on SNES

5397:     Input Parameter:
5398: .   snes - iterative context obtained from SNESCreate()

5400:     Output Parameter:
5401: .   side - the preconditioning side, where side is one of
5402: .vb
5403:       PC_LEFT - left preconditioning
5404:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5405: .ve

5407:     Options Database Keys:
5408: .   -snes_pc_side <right,left>

5410:     Notes:
5411:     SNESNRICHARDSON and SNESNCG only support left preconditioning.

5413:     Level: intermediate

5415: .seealso: SNESGetNPCSide(), KSPSetPCSide()
5416: @*/
5417: PetscErrorCode  SNESSetNPCSide(SNES snes,PCSide side)
5418: {
5422:   snes->npcside= side;
5423:   return(0);
5424: }

5426: /*@
5427:     SNESGetNPCSide - Gets the preconditioning side.

5429:     Not Collective

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:     Level: intermediate

5443: .seealso: SNESSetNPCSide(), KSPGetPCSide()
5444: @*/
5445: PetscErrorCode  SNESGetNPCSide(SNES snes,PCSide *side)
5446: {
5450:   *side = snes->npcside;
5451:   return(0);
5452: }

5454: /*@
5455:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

5457:   Collective on SNES

5459:   Input Parameters:
5460: + snes - iterative context obtained from SNESCreate()
5461: - linesearch   - the linesearch object

5463:   Notes:
5464:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
5465:   to configure it using the API).

5467:   Level: developer

5469: .seealso: SNESGetLineSearch()
5470: @*/
5471: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5472: {

5479:   PetscObjectReference((PetscObject) linesearch);
5480:   SNESLineSearchDestroy(&snes->linesearch);

5482:   snes->linesearch = linesearch;

5484:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5485:   return(0);
5486: }

5488: /*@
5489:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
5490:   or creates a default line search instance associated with the SNES and returns it.

5492:   Not Collective

5494:   Input Parameter:
5495: . snes - iterative context obtained from SNESCreate()

5497:   Output Parameter:
5498: . linesearch - linesearch context

5500:   Level: beginner

5502: .seealso: SNESSetLineSearch(), SNESLineSearchCreate()
5503: @*/
5504: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5505: {
5507:   const char     *optionsprefix;

5512:   if (!snes->linesearch) {
5513:     SNESGetOptionsPrefix(snes, &optionsprefix);
5514:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
5515:     SNESLineSearchSetSNES(snes->linesearch, snes);
5516:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
5517:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
5518:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5519:   }
5520:   *linesearch = snes->linesearch;
5521:   return(0);
5522: }