Actual source code: snes.c

petsc-master 2016-12-04
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  2:  #include <petsc/private/snesimpl.h>
  3:  #include <petscdmshell.h>
  4:  #include <petscdraw.h>

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

  9: /* Logging support */
 10: PetscClassId  SNES_CLASSID, DMSNES_CLASSID;
 11: PetscLogEvent SNES_Solve, 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: .keywords: SNES, set, initial guess, nonzero

 35: .seealso: SNESGetErrorIfNotConverged(), KSPGetErrorIfNotConverged(), KSPSetErrorIFNotConverged()
 36: @*/
 37: PetscErrorCode  SNESSetErrorIfNotConverged(SNES snes,PetscBool flg)
 38: {
 42:   snes->errorifnotconverged = flg;
 43:   return(0);
 44: }

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

 51:    Not Collective

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

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

 59:    Level: intermediate

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

 63: .seealso:  SNESSetErrorIfNotConverged(), KSPGetErrorIfNotConverged(), KSPSetErrorIFNotConverged()
 64: @*/
 65: PetscErrorCode  SNESGetErrorIfNotConverged(SNES snes,PetscBool  *flag)
 66: {
 70:   *flag = snes->errorifnotconverged;
 71:   return(0);
 72: }

 76: /*@
 77:     SNESSetAlwaysComputesFinalResidual - does the SNES always compute the residual at the final solution?

 79:    Logically Collective on SNES

 81:     Input Parameters:
 82: +   snes - the shell SNES
 83: -   flg - is the residual computed?

 85:    Level: advanced

 87: .seealso: SNESGetAlwaysComputesFinalResidual()
 88: @*/
 89: PetscErrorCode  SNESSetAlwaysComputesFinalResidual(SNES snes, PetscBool flg)
 90: {
 93:   snes->alwayscomputesfinalresidual = flg;
 94:   return(0);
 95: }

 99: /*@
100:     SNESGetAlwaysComputesFinalResidual - does the SNES always compute the residual at the final solution?

102:    Logically Collective on SNES

104:     Input Parameter:
105: .   snes - the shell SNES

107:     Output Parameter:
108: .   flg - is the residual computed?

110:    Level: advanced

112: .seealso: SNESSetAlwaysComputesFinalResidual()
113: @*/
114: PetscErrorCode  SNESGetAlwaysComputesFinalResidual(SNES snes, PetscBool *flg)
115: {
118:   *flg = snes->alwayscomputesfinalresidual;
119:   return(0);
120: }

124: /*@
125:    SNESSetFunctionDomainError - tells SNES that the input vector to your SNESFunction is not
126:      in the functions domain. For example, negative pressure.

128:    Logically Collective on SNES

130:    Input Parameters:
131: .  snes - the SNES context

133:    Level: advanced

135: .keywords: SNES, view

137: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction
138: @*/
139: PetscErrorCode  SNESSetFunctionDomainError(SNES snes)
140: {
143:   if (snes->errorifnotconverged) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"User code indicates input vector is not in the function domain");
144:   snes->domainerror = PETSC_TRUE;
145:   return(0);
146: }

150: /*@
151:    SNESGetFunctionDomainError - Gets the status of the domain error after a call to SNESComputeFunction;

153:    Logically Collective on SNES

155:    Input Parameters:
156: .  snes - the SNES context

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

161:    Level: advanced

163: .keywords: SNES, view

165: .seealso: SNESSetFunctionDomainError(), SNESComputeFunction()
166: @*/
167: PetscErrorCode  SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
168: {
172:   *domainerror = snes->domainerror;
173:   return(0);
174: }

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

181:   Collective on PetscViewer

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

188:    Level: intermediate

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

193:   Notes for advanced users:
194:   Most users should not need to know the details of the binary storage
195:   format, since SNESLoad() and TSView() completely hide these details.
196:   But for anyone who's interested, the standard binary matrix storage
197:   format is
198: .vb
199:      has not yet been determined
200: .ve

202: .seealso: PetscViewerBinaryOpen(), SNESView(), MatLoad(), VecLoad()
203: @*/
204: PetscErrorCode  SNESLoad(SNES snes, PetscViewer viewer)
205: {
207:   PetscBool      isbinary;
208:   PetscInt       classid;
209:   char           type[256];
210:   KSP            ksp;
211:   DM             dm;
212:   DMSNES         dmsnes;

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

220:   PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
221:   if (classid != SNES_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONG,"Not SNES next in file");
222:   PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
223:   SNESSetType(snes, type);
224:   if (snes->ops->load) {
225:     (*snes->ops->load)(snes,viewer);
226:   }
227:   SNESGetDM(snes,&dm);
228:   DMGetDMSNES(dm,&dmsnes);
229:   DMSNESLoad(dmsnes,viewer);
230:   SNESGetKSP(snes,&ksp);
231:   KSPLoad(ksp,viewer);
232:   return(0);
233: }

235:  #include <petscdraw.h>
236: #if defined(PETSC_HAVE_SAWS)
237:  #include <petscviewersaws.h>
238: #endif
241: /*@C
242:    SNESView - Prints the SNES data structure.

244:    Collective on SNES

246:    Input Parameters:
247: +  SNES - the SNES context
248: -  viewer - visualization context

250:    Options Database Key:
251: .  -snes_view - Calls SNESView() at end of SNESSolve()

253:    Notes:
254:    The available visualization contexts include
255: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
256: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
257:          output where only the first processor opens
258:          the file.  All other processors send their
259:          data to the first processor to print.

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

264:    Level: beginner

266: .keywords: SNES, view

268: .seealso: PetscViewerASCIIOpen()
269: @*/
270: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
271: {
272:   SNESKSPEW      *kctx;
274:   KSP            ksp;
275:   SNESLineSearch linesearch;
276:   PetscBool      iascii,isstring,isbinary,isdraw;
277:   DMSNES         dmsnes;
278: #if defined(PETSC_HAVE_SAWS)
279:   PetscBool      issaws;
280: #endif

284:   if (!viewer) {
285:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&viewer);
286:   }

290:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
291:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
292:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
293:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
294: #if defined(PETSC_HAVE_SAWS)
295:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
296: #endif
297:   if (iascii) {
298:     SNESNormSchedule normschedule;

300:     PetscObjectPrintClassNamePrefixType((PetscObject)snes,viewer);
301:     if (!snes->setupcalled) {
302:       PetscViewerASCIIPrintf(viewer,"  SNES has not been set up so information may be incomplete\n");
303:     }
304:     if (snes->ops->view) {
305:       PetscViewerASCIIPushTab(viewer);
306:       (*snes->ops->view)(snes,viewer);
307:       PetscViewerASCIIPopTab(viewer);
308:     }
309:     PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
310:     PetscViewerASCIIPrintf(viewer,"  tolerances: relative=%g, absolute=%g, solution=%g\n",(double)snes->rtol,(double)snes->abstol,(double)snes->stol);
311:     PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",snes->linear_its);
312:     PetscViewerASCIIPrintf(viewer,"  total number of function evaluations=%D\n",snes->nfuncs);
313:     SNESGetNormSchedule(snes, &normschedule);
314:     if (normschedule > 0) {PetscViewerASCIIPrintf(viewer,"  norm schedule %s\n",SNESNormSchedules[normschedule]);}
315:     if (snes->gridsequence) {
316:       PetscViewerASCIIPrintf(viewer,"  total number of grid sequence refinements=%D\n",snes->gridsequence);
317:     }
318:     if (snes->ksp_ewconv) {
319:       kctx = (SNESKSPEW*)snes->kspconvctx;
320:       if (kctx) {
321:         PetscViewerASCIIPrintf(viewer,"  Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
322:         PetscViewerASCIIPrintf(viewer,"    rtol_0=%g, rtol_max=%g, threshold=%g\n",(double)kctx->rtol_0,(double)kctx->rtol_max,(double)kctx->threshold);
323:         PetscViewerASCIIPrintf(viewer,"    gamma=%g, alpha=%g, alpha2=%g\n",(double)kctx->gamma,(double)kctx->alpha,(double)kctx->alpha2);
324:       }
325:     }
326:     if (snes->lagpreconditioner == -1) {
327:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is never rebuilt\n");
328:     } else if (snes->lagpreconditioner > 1) {
329:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is rebuilt every %D new Jacobians\n",snes->lagpreconditioner);
330:     }
331:     if (snes->lagjacobian == -1) {
332:       PetscViewerASCIIPrintf(viewer,"  Jacobian is never rebuilt\n");
333:     } else if (snes->lagjacobian > 1) {
334:       PetscViewerASCIIPrintf(viewer,"  Jacobian is rebuilt every %D SNES iterations\n",snes->lagjacobian);
335:     }
336:   } else if (isstring) {
337:     const char *type;
338:     SNESGetType(snes,&type);
339:     PetscViewerStringSPrintf(viewer," %-3.3s",type);
340:   } else if (isbinary) {
341:     PetscInt    classid = SNES_FILE_CLASSID;
342:     MPI_Comm    comm;
343:     PetscMPIInt rank;
344:     char        type[256];

346:     PetscObjectGetComm((PetscObject)snes,&comm);
347:     MPI_Comm_rank(comm,&rank);
348:     if (!rank) {
349:       PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);
350:       PetscStrncpy(type,((PetscObject)snes)->type_name,sizeof(type));
351:       PetscViewerBinaryWrite(viewer,type,sizeof(type),PETSC_CHAR,PETSC_FALSE);
352:     }
353:     if (snes->ops->view) {
354:       (*snes->ops->view)(snes,viewer);
355:     }
356:   } else if (isdraw) {
357:     PetscDraw draw;
358:     char      str[36];
359:     PetscReal x,y,bottom,h;

361:     PetscViewerDrawGetDraw(viewer,0,&draw);
362:     PetscDrawGetCurrentPoint(draw,&x,&y);
363:     PetscStrcpy(str,"SNES: ");
364:     PetscStrcat(str,((PetscObject)snes)->type_name);
365:     PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_BLUE,PETSC_DRAW_BLACK,str,NULL,&h);
366:     bottom = y - h;
367:     PetscDrawPushCurrentPoint(draw,x,bottom);
368:     if (snes->ops->view) {
369:       (*snes->ops->view)(snes,viewer);
370:     }
371: #if defined(PETSC_HAVE_SAWS)
372:   } else if (issaws) {
373:     PetscMPIInt rank;
374:     const char *name;

376:     PetscObjectGetName((PetscObject)snes,&name);
377:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
378:     if (!((PetscObject)snes)->amsmem && !rank) {
379:       char       dir[1024];

381:       PetscObjectViewSAWs((PetscObject)snes,viewer);
382:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
383:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
384:       if (!snes->conv_hist) {
385:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
386:       }
387:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
388:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
389:     }
390: #endif
391:   }
392:   if (snes->linesearch) {
393:     PetscViewerASCIIPushTab(viewer);
394:     SNESGetLineSearch(snes, &linesearch);
395:     SNESLineSearchView(linesearch, viewer);
396:     PetscViewerASCIIPopTab(viewer);
397:   }
398:   if (snes->pc && snes->usespc) {
399:     PetscViewerASCIIPushTab(viewer);
400:     SNESView(snes->pc, viewer);
401:     PetscViewerASCIIPopTab(viewer);
402:   }
403:   PetscViewerASCIIPushTab(viewer);
404:   DMGetDMSNES(snes->dm,&dmsnes);
405:   DMSNESView(dmsnes, viewer);
406:   PetscViewerASCIIPopTab(viewer);
407:   if (snes->usesksp) {
408:     SNESGetKSP(snes,&ksp);
409:     PetscViewerASCIIPushTab(viewer);
410:     KSPView(ksp,viewer);
411:     PetscViewerASCIIPopTab(viewer);
412:   }
413:   if (isdraw) {
414:     PetscDraw draw;
415:     PetscViewerDrawGetDraw(viewer,0,&draw);
416:     PetscDrawPopCurrentPoint(draw);
417:   }
418:   return(0);
419: }

421: /*
422:   We retain a list of functions that also take SNES command
423:   line options. These are called at the end SNESSetFromOptions()
424: */
425: #define MAXSETFROMOPTIONS 5
426: static PetscInt numberofsetfromoptions;
427: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

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

434:   Not Collective

436:   Input Parameter:
437: . snescheck - function that checks for options

439:   Level: developer

441: .seealso: SNESSetFromOptions()
442: @*/
443: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
444: {
446:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
447:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
448:   return(0);
449: }

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

455: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
456: {
457:   Mat            J;
458:   KSP            ksp;
459:   PC             pc;
460:   PetscBool      match;
462:   MatNullSpace   nullsp;


467:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
468:     Mat A = snes->jacobian, B = snes->jacobian_pre;
469:     MatCreateVecs(A ? A : B, NULL,&snes->vec_func);
470:   }

472:   if (version == 1) {
473:     MatCreateSNESMF(snes,&J);
474:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
475:     MatSetFromOptions(J);
476:   } else if (version == 2) {
477:     if (!snes->vec_func) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first");
478: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128)
479:     SNESDefaultMatrixFreeCreate2(snes,snes->vec_func,&J);
480: #else
481:     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP, "matrix-free operator rutines (version 2)");
482: #endif
483:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator rutines, only version 1 and 2");

485:   /* attach any user provided null space that was on Amat to the newly created matrix free matrix */
486:   if (snes->jacobian) {
487:     MatGetNullSpace(snes->jacobian,&nullsp);
488:     if (nullsp) {
489:       MatSetNullSpace(J,nullsp);
490:     }
491:   }

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

496:     /* This version replaces the user provided Jacobian matrix with a
497:        matrix-free version but still employs the user-provided preconditioner matrix. */
498:     SNESSetJacobian(snes,J,0,0,0);
499:   } else {
500:     /* This version replaces both the user-provided Jacobian and the user-
501:      provided preconditioner Jacobian with the default matrix free version. */
502:     if ((snes->pcside == PC_LEFT) && snes->pc) {
503:       if (!snes->jacobian){SNESSetJacobian(snes,J,0,0,0);}
504:     } else {
505:       SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,0);
506:     }
507:     /* Force no preconditioner */
508:     SNESGetKSP(snes,&ksp);
509:     KSPGetPC(ksp,&pc);
510:     PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&match);
511:     if (!match) {
512:       PetscInfo(snes,"Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n");
513:       PCSetType(pc,PCNONE);
514:     }
515:   }
516:   MatDestroy(&J);
517:   return(0);
518: }

522: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
523: {
524:   SNES           snes = (SNES)ctx;
526:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

529:   if (PetscLogPrintInfo) {
530:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
531:     DMGetRefineLevel(dmfine,&finelevel);
532:     DMGetCoarsenLevel(dmfine,&fineclevel);
533:     DMGetRefineLevel(dmcoarse,&coarselevel);
534:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
535:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
536:   }
537:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
538:   else {
539:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
540:     Xfine = Xfine_named;
541:   }
542:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
543:   if (Inject) {
544:     MatRestrict(Inject,Xfine,Xcoarse);
545:   } else {
546:     MatRestrict(Restrict,Xfine,Xcoarse);
547:     VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
548:   }
549:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
550:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
551:   return(0);
552: }

556: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
557: {

561:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
562:   return(0);
563: }

567: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
568:  * safely call SNESGetDM() in their residual evaluation routine. */
569: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,void *ctx)
570: {
571:   SNES           snes = (SNES)ctx;
573:   Mat            Asave = A,Bsave = B;
574:   Vec            X,Xnamed = NULL;
575:   DM             dmsave;
576:   void           *ctxsave;
577:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);

580:   dmsave = snes->dm;
581:   KSPGetDM(ksp,&snes->dm);
582:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
583:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
584:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
585:     X    = Xnamed;
586:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
587:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
588:     if (jac == SNESComputeJacobianDefaultColor) {
589:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,0);
590:     }
591:   }
592:   /* put the previous context back */

594:   SNESComputeJacobian(snes,X,A,B);
595:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
596:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
597:   }

599:   if (A != Asave || B != Bsave) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_SUP,"No support for changing matrices at this time");
600:   if (Xnamed) {
601:     DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
602:   }
603:   snes->dm = dmsave;
604:   return(0);
605: }

609: /*@
610:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

612:    Collective

614:    Input Arguments:
615: .  snes - snes to configure

617:    Level: developer

619: .seealso: SNESSetUp()
620: @*/
621: PetscErrorCode SNESSetUpMatrices(SNES snes)
622: {
624:   DM             dm;
625:   DMSNES         sdm;

628:   SNESGetDM(snes,&dm);
629:   DMGetDMSNES(dm,&sdm);
630:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_PLIB,"DMSNES not properly configured");
631:   else if (!snes->jacobian && snes->mf) {
632:     Mat  J;
633:     void *functx;
634:     MatCreateSNESMF(snes,&J);
635:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
636:     MatSetFromOptions(J);
637:     SNESGetFunction(snes,NULL,NULL,&functx);
638:     SNESSetJacobian(snes,J,J,0,0);
639:     MatDestroy(&J);
640:   } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
641:     Mat J,B;
642:     MatCreateSNESMF(snes,&J);
643:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
644:     MatSetFromOptions(J);
645:     DMCreateMatrix(snes->dm,&B);
646:     /* sdm->computejacobian was already set to reach here */
647:     SNESSetJacobian(snes,J,B,NULL,NULL);
648:     MatDestroy(&J);
649:     MatDestroy(&B);
650:   } else if (!snes->jacobian_pre) {
651:     Mat J,B;
652:     J    = snes->jacobian;
653:     DMCreateMatrix(snes->dm,&B);
654:     SNESSetJacobian(snes,J ? J : B,B,NULL,NULL);
655:     MatDestroy(&B);
656:   }
657:   {
658:     KSP ksp;
659:     SNESGetKSP(snes,&ksp);
660:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
661:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
662:   }
663:   return(0);
664: }

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

671:    Collective on SNES

673:    Input Parameters:
674: +  snes - SNES object you wish to monitor
675: .  name - the monitor type one is seeking
676: .  help - message indicating what monitoring is done
677: .  manual - manual page for the monitor
678: .  monitor - the monitor function
679: -  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

681:    Level: developer

683: .seealso: PetscOptionsGetViewer(), PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(),
684:           PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool()
685:           PetscOptionsInt(), PetscOptionsString(), PetscOptionsReal(), PetscOptionsBool(),
686:           PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(),
687:           PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(),
688:           PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(),
689:           PetscOptionsFList(), PetscOptionsEList()
690: @*/
691: PetscErrorCode  SNESMonitorSetFromOptions(SNES snes,const char name[],const char help[], const char manual[],PetscErrorCode (*monitor)(SNES,PetscInt,PetscReal,PetscViewerAndFormat*),PetscErrorCode (*monitorsetup)(SNES,PetscViewerAndFormat*))
692: {
693:   PetscErrorCode    ierr;
694:   PetscViewer       viewer;
695:   PetscViewerFormat format;
696:   PetscBool         flg;

699:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,name,&viewer,&format,&flg);
700:   if (flg) {
701:     PetscViewerAndFormat *vf;
702:     PetscViewerAndFormatCreate(viewer,format,&vf);
703:     PetscObjectDereference((PetscObject)viewer);
704:     if (monitorsetup) {
705:       (*monitorsetup)(snes,vf);
706:     }
707:     SNESMonitorSet(snes,(PetscErrorCode (*)(SNES,PetscInt,PetscReal,void*))monitor,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);
708:   }
709:   return(0);
710: }

714: /*@
715:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

717:    Collective on SNES

719:    Input Parameter:
720: .  snes - the SNES context

722:    Options Database Keys:
723: +  -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, SNESType for complete list
724: .  -snes_stol - convergence tolerance in terms of the norm
725:                 of the change in the solution between steps
726: .  -snes_atol <abstol> - absolute tolerance of residual norm
727: .  -snes_rtol <rtol> - relative decrease in tolerance norm from initial
728: .  -snes_divergence_tolerance <divtol> - if the residual goes above divtol*rnorm0, exit with divergence
729: .  -snes_max_it <max_it> - maximum number of iterations
730: .  -snes_max_funcs <max_funcs> - maximum number of function evaluations
731: .  -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
732: .  -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
733: .  -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
734: .  -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
735: .  -snes_trtol <trtol> - trust region tolerance
736: .  -snes_no_convergence_test - skip convergence test in nonlinear
737:                                solver; hence iterations will continue until max_it
738:                                or some other criterion is reached. Saves expense
739:                                of convergence test
740: .  -snes_monitor [ascii][:filename][:viewer format] - prints residual norm at each iteration. if no filename given prints to stdout
741: .  -snes_monitor_solution [ascii binary draw][:filename][:viewer format] - plots solution at each iteration
742: .  -snes_monitor_residual [ascii binary draw][:filename][:viewer format] - plots residual (not its norm) at each iteration
743: .  -snes_monitor_solution_update [ascii binary draw][:filename][:viewer format] - plots update to solution at each iteration
744: .  -snes_monitor_lg_residualnorm - plots residual norm at each iteration
745: .  -snes_monitor_lg_range - plots residual norm at each iteration
746: .  -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
747: .  -snes_fd_color - use finite differences with coloring to compute Jacobian
748: .  -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
749: -  -snes_converged_reason - print the reason for convergence/divergence after each solve

751:     Options Database for Eisenstat-Walker method:
752: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
753: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
754: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
755: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
756: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
757: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
758: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
759: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

761:    Notes:
762:    To see all options, run your program with the -help option or consult
763:    Users-Manual: ch_snes

765:    Level: beginner

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

769: .seealso: SNESSetOptionsPrefix()
770: @*/
771: PetscErrorCode  SNESSetFromOptions(SNES snes)
772: {
773:   PetscBool      flg,pcset,persist,set;
774:   PetscInt       i,indx,lag,grids;
775:   const char     *deft        = SNESNEWTONLS;
776:   const char     *convtests[] = {"default","skip"};
777:   SNESKSPEW      *kctx        = NULL;
778:   char           type[256], monfilename[PETSC_MAX_PATH_LEN];
780:   PCSide         pcside;
781:   const char     *optionsprefix;

785:   SNESRegisterAll();
786:   PetscObjectOptionsBegin((PetscObject)snes);
787:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
788:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
789:   if (flg) {
790:     SNESSetType(snes,type);
791:   } else if (!((PetscObject)snes)->type_name) {
792:     SNESSetType(snes,deft);
793:   }
794:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,NULL);
795:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,NULL);

797:   PetscOptionsReal("-snes_rtol","Stop if decrease in function norm less than","SNESSetTolerances",snes->rtol,&snes->rtol,NULL);
798:   PetscOptionsReal("-snes_divergence_tolerance","Stop if residual norm increases by this factor","SNESSetDivergenceTolerance",snes->divtol,&snes->divtol,NULL);
799:   PetscOptionsInt("-snes_max_it","Maximum iterations","SNESSetTolerances",snes->max_its,&snes->max_its,NULL);
800:   PetscOptionsInt("-snes_max_funcs","Maximum function evaluations","SNESSetTolerances",snes->max_funcs,&snes->max_funcs,NULL);
801:   PetscOptionsInt("-snes_max_fail","Maximum nonlinear step failures","SNESSetMaxNonlinearStepFailures",snes->maxFailures,&snes->maxFailures,NULL);
802:   PetscOptionsInt("-snes_max_linear_solve_fail","Maximum failures in linear solves allowed","SNESSetMaxLinearSolveFailures",snes->maxLinearSolveFailures,&snes->maxLinearSolveFailures,NULL);
803:   PetscOptionsBool("-snes_error_if_not_converged","Generate error if solver does not converge","SNESSetErrorIfNotConverged",snes->errorifnotconverged,&snes->errorifnotconverged,NULL);

805:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
806:   if (flg) {
807:     SNESSetLagPreconditioner(snes,lag);
808:   }
809:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
810:   if (flg) {
811:     SNESSetLagPreconditionerPersists(snes,persist);
812:   }
813:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
814:   if (flg) {
815:     SNESSetLagJacobian(snes,lag);
816:   }
817:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
818:   if (flg) {
819:     SNESSetLagJacobianPersists(snes,persist);
820:   }

822:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
823:   if (flg) {
824:     SNESSetGridSequence(snes,grids);
825:   }

827:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,2,"default",&indx,&flg);
828:   if (flg) {
829:     switch (indx) {
830:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
831:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL);    break;
832:     }
833:   }

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

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

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

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

845:   PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,NULL);
846:   PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,NULL);
847:   PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,NULL);
848:   PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,NULL);
849:   PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,NULL);
850:   PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,NULL);
851:   PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",kctx->threshold,&kctx->threshold,NULL);

853:   flg  = PETSC_FALSE;
854:   PetscOptionsBool("-snes_check_jacobian","Check each Jacobian with a differenced one","SNESUpdateCheckJacobian",flg,&flg,&set);
855:   if (set && flg) {
856:     SNESSetUpdate(snes,SNESUpdateCheckJacobian);
857:   }

859:   flg  = PETSC_FALSE;
860:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,&set);
861:   if (set && flg) {SNESMonitorCancel(snes);}

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

867:   SNESMonitorSetFromOptions(snes,"-snes_monitor_ratio","Monitor ratios of the norm of function for consecutive steps","SNESMonitorRatio",SNESMonitorRatio,SNESMonitorRatioSetUp);
868:   SNESMonitorSetFromOptions(snes,"-snes_monitor_field","Monitor norm of function (split into fields)","SNESMonitorDefaultField",SNESMonitorDefaultField,NULL);
869:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution","View solution at each iteration","SNESMonitorSolution",SNESMonitorSolution,NULL);
870:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution_update","View correction at each iteration","SNESMonitorSolutionUpdate",SNESMonitorSolutionUpdate,NULL);
871:   SNESMonitorSetFromOptions(snes,"-snes_monitor_residual","View residual at each iteration","SNESMonitorResidual",SNESMonitorResidual,NULL);
872:   SNESMonitorSetFromOptions(snes,"-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",SNESMonitorJacUpdateSpectrum,NULL);
873:   SNESMonitorSetFromOptions(snes,"-snes_monitor_fields","Monitor norm of function per field","SNESMonitorSet",SNESMonitorFields,NULL);

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


879:   flg  = PETSC_FALSE;
880:   PetscOptionsBool("-snes_monitor_lg_residualnorm","Plot function norm at each iteration","SNESMonitorLGResidualNorm",flg,&flg,NULL);
881:   if (flg) {
882:     PetscDrawLG ctx;

884:     SNESMonitorLGCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
885:     SNESMonitorSet(snes,SNESMonitorLGResidualNorm,ctx,(PetscErrorCode (*)(void**))PetscDrawLGDestroy);
886:   }
887:   flg  = PETSC_FALSE;
888:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
889:   if (flg) {
890:     PetscViewer ctx;

892:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
893:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
894:   }



898:   flg  = PETSC_FALSE;
899:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
900:   if (flg) {
901:     void *functx;
902:     SNESGetFunction(snes,NULL,NULL,&functx);
903:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
904:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
905:   }

907:   flg  = PETSC_FALSE;
908:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
909:   if (flg) {
910:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
911:   }

913:   flg  = PETSC_FALSE;
914:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
915:   if (flg) {
916:     DM             dm;
917:     DMSNES         sdm;
918:     SNESGetDM(snes,&dm);
919:     DMGetDMSNES(dm,&sdm);
920:     sdm->jacobianctx = NULL;
921:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,0);
922:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
923:   }

925:   flg  = PETSC_FALSE;
926:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","MatCreateSNESMF",PETSC_FALSE,&snes->mf_operator,&flg);
927:   if (flg && snes->mf_operator) {
928:     snes->mf_operator = PETSC_TRUE;
929:     snes->mf          = PETSC_TRUE;
930:   }
931:   flg  = PETSC_FALSE;
932:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","MatCreateSNESMF",PETSC_FALSE,&snes->mf,&flg);
933:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
934:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,0);

936:   flg  = PETSC_FALSE;
937:   SNESGetNPCSide(snes,&pcside);
938:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetNPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
939:   if (flg) {SNESSetNPCSide(snes,pcside);}

941: #if defined(PETSC_HAVE_SAWS)
942:   /*
943:     Publish convergence information using SAWs
944:   */
945:   flg  = PETSC_FALSE;
946:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
947:   if (flg) {
948:     void *ctx;
949:     SNESMonitorSAWsCreate(snes,&ctx);
950:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
951:   }
952: #endif
953: #if defined(PETSC_HAVE_SAWS)
954:   {
955:   PetscBool set;
956:   flg  = PETSC_FALSE;
957:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
958:   if (set) {
959:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
960:   }
961:   }
962: #endif

964:   for (i = 0; i < numberofsetfromoptions; i++) {
965:     (*othersetfromoptions[i])(snes);
966:   }

968:   if (snes->ops->setfromoptions) {
969:     (*snes->ops->setfromoptions)(PetscOptionsObject,snes);
970:   }

972:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
973:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)snes);
974:   PetscOptionsEnd();

976:   if (!snes->linesearch) {
977:     SNESGetLineSearch(snes, &snes->linesearch);
978:   }
979:   SNESLineSearchSetFromOptions(snes->linesearch);

981:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
982:   KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
983:   KSPSetFromOptions(snes->ksp);

985:   /* if someone has set the SNES NPC type, create it. */
986:   SNESGetOptionsPrefix(snes, &optionsprefix);
987:   PetscOptionsHasName(((PetscObject)snes)->options,optionsprefix, "-npc_snes_type", &pcset);
988:   if (pcset && (!snes->pc)) {
989:     SNESGetNPC(snes, &snes->pc);
990:   }
991:   return(0);
992: }

996: /*@C
997:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
998:    the nonlinear solvers.

1000:    Logically Collective on SNES

1002:    Input Parameters:
1003: +  snes - the SNES context
1004: .  compute - function to compute the context
1005: -  destroy - function to destroy the context

1007:    Level: intermediate

1009:    Notes:
1010:    This function is currently not available from Fortran.

1012: .keywords: SNES, nonlinear, set, application, context

1014: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
1015: @*/
1016: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
1017: {
1020:   snes->ops->usercompute = compute;
1021:   snes->ops->userdestroy = destroy;
1022:   return(0);
1023: }

1027: /*@
1028:    SNESSetApplicationContext - Sets the optional user-defined context for
1029:    the nonlinear solvers.

1031:    Logically Collective on SNES

1033:    Input Parameters:
1034: +  snes - the SNES context
1035: -  usrP - optional user context

1037:    Level: intermediate

1039:    Fortran Notes: To use this from Fortran you must write a Fortran interface definition for this
1040:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1042: .keywords: SNES, nonlinear, set, application, context

1044: .seealso: SNESGetApplicationContext()
1045: @*/
1046: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
1047: {
1049:   KSP            ksp;

1053:   SNESGetKSP(snes,&ksp);
1054:   KSPSetApplicationContext(ksp,usrP);
1055:   snes->user = usrP;
1056:   return(0);
1057: }

1061: /*@
1062:    SNESGetApplicationContext - Gets the user-defined context for the
1063:    nonlinear solvers.

1065:    Not Collective

1067:    Input Parameter:
1068: .  snes - SNES context

1070:    Output Parameter:
1071: .  usrP - user context

1073:    Fortran Notes: To use this from Fortran you must write a Fortran interface definition for this
1074:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1076:    Level: intermediate

1078: .keywords: SNES, nonlinear, get, application, context

1080: .seealso: SNESSetApplicationContext()
1081: @*/
1082: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
1083: {
1086:   *(void**)usrP = snes->user;
1087:   return(0);
1088: }

1092: /*@
1093:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1094:    at this time.

1096:    Not Collective

1098:    Input Parameter:
1099: .  snes - SNES context

1101:    Output Parameter:
1102: .  iter - iteration number

1104:    Notes:
1105:    For example, during the computation of iteration 2 this would return 1.

1107:    This is useful for using lagged Jacobians (where one does not recompute the
1108:    Jacobian at each SNES iteration). For example, the code
1109: .vb
1110:       SNESGetIterationNumber(snes,&it);
1111:       if (!(it % 2)) {
1112:         [compute Jacobian here]
1113:       }
1114: .ve
1115:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1116:    recomputed every second SNES iteration.

1118:    Level: intermediate

1120: .keywords: SNES, nonlinear, get, iteration, number,

1122: .seealso:   SNESGetLinearSolveIterations()
1123: @*/
1124: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1125: {
1129:   *iter = snes->iter;
1130:   return(0);
1131: }

1135: /*@
1136:    SNESSetIterationNumber - Sets the current iteration number.

1138:    Not Collective

1140:    Input Parameter:
1141: .  snes - SNES context
1142: .  iter - iteration number

1144:    Level: developer

1146: .keywords: SNES, nonlinear, set, iteration, number,

1148: .seealso:   SNESGetLinearSolveIterations()
1149: @*/
1150: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1151: {

1156:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1157:   snes->iter = iter;
1158:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1159:   return(0);
1160: }

1164: /*@
1165:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1166:    attempted by the nonlinear solver.

1168:    Not Collective

1170:    Input Parameter:
1171: .  snes - SNES context

1173:    Output Parameter:
1174: .  nfails - number of unsuccessful steps attempted

1176:    Notes:
1177:    This counter is reset to zero for each successive call to SNESSolve().

1179:    Level: intermediate

1181: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1183: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1184:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1185: @*/
1186: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1187: {
1191:   *nfails = snes->numFailures;
1192:   return(0);
1193: }

1197: /*@
1198:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1199:    attempted by the nonlinear solver before it gives up.

1201:    Not Collective

1203:    Input Parameters:
1204: +  snes     - SNES context
1205: -  maxFails - maximum of unsuccessful steps

1207:    Level: intermediate

1209: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1211: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1212:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1213: @*/
1214: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1215: {
1218:   snes->maxFailures = maxFails;
1219:   return(0);
1220: }

1224: /*@
1225:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1226:    attempted by the nonlinear solver before it gives up.

1228:    Not Collective

1230:    Input Parameter:
1231: .  snes     - SNES context

1233:    Output Parameter:
1234: .  maxFails - maximum of unsuccessful steps

1236:    Level: intermediate

1238: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1240: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1241:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1243: @*/
1244: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1245: {
1249:   *maxFails = snes->maxFailures;
1250:   return(0);
1251: }

1255: /*@
1256:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1257:      done by SNES.

1259:    Not Collective

1261:    Input Parameter:
1262: .  snes     - SNES context

1264:    Output Parameter:
1265: .  nfuncs - number of evaluations

1267:    Level: intermediate

1269:    Notes: Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1271: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1273: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1274: @*/
1275: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1276: {
1280:   *nfuncs = snes->nfuncs;
1281:   return(0);
1282: }

1286: /*@
1287:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1288:    linear solvers.

1290:    Not Collective

1292:    Input Parameter:
1293: .  snes - SNES context

1295:    Output Parameter:
1296: .  nfails - number of failed solves

1298:    Level: intermediate

1300:    Options Database Keys:
1301: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1303:    Notes:
1304:    This counter is reset to zero for each successive call to SNESSolve().

1306: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1308: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1309: @*/
1310: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1311: {
1315:   *nfails = snes->numLinearSolveFailures;
1316:   return(0);
1317: }

1321: /*@
1322:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1323:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1325:    Logically Collective on SNES

1327:    Input Parameters:
1328: +  snes     - SNES context
1329: -  maxFails - maximum allowed linear solve failures

1331:    Level: intermediate

1333:    Options Database Keys:
1334: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1336:    Notes: By default this is 0; that is SNES returns on the first failed linear solve

1338: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1340: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations()
1341: @*/
1342: PetscErrorCode  SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1343: {
1347:   snes->maxLinearSolveFailures = maxFails;
1348:   return(0);
1349: }

1353: /*@
1354:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1355:      are allowed before SNES terminates

1357:    Not Collective

1359:    Input Parameter:
1360: .  snes     - SNES context

1362:    Output Parameter:
1363: .  maxFails - maximum of unsuccessful solves allowed

1365:    Level: intermediate

1367:    Notes: By default this is 1; that is SNES returns on the first failed linear solve

1369: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1371: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1372: @*/
1373: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1374: {
1378:   *maxFails = snes->maxLinearSolveFailures;
1379:   return(0);
1380: }

1384: /*@
1385:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1386:    used by the nonlinear solver.

1388:    Not Collective

1390:    Input Parameter:
1391: .  snes - SNES context

1393:    Output Parameter:
1394: .  lits - number of linear iterations

1396:    Notes:
1397:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1399:    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 
1400:    then call KSPGetIterationNumber() after the failed solve.

1402:    Level: intermediate

1404: .keywords: SNES, nonlinear, get, number, linear, iterations

1406: .seealso:  SNESGetIterationNumber(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1407: @*/
1408: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1409: {
1413:   *lits = snes->linear_its;
1414:   return(0);
1415: }

1419: /*@
1420:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1421:    are reset every time SNESSolve() is called.

1423:    Logically Collective on SNES

1425:    Input Parameter:
1426: +  snes - SNES context
1427: -  reset - whether to reset the counters or not

1429:    Notes:
1430:    This defaults to PETSC_TRUE

1432:    Level: developer

1434: .keywords: SNES, nonlinear, set, reset, number, linear, iterations

1436: .seealso:  SNESGetNumberFunctionEvals(), SNESGetLinearSolveIterations(), SNESGetNPC()
1437: @*/
1438: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1439: {
1443:   snes->counters_reset = reset;
1444:   return(0);
1445: }


1450: /*@
1451:    SNESSetKSP - Sets a KSP context for the SNES object to use

1453:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1455:    Input Parameters:
1456: +  snes - the SNES context
1457: -  ksp - the KSP context

1459:    Notes:
1460:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1461:    so this routine is rarely needed.

1463:    The KSP object that is already in the SNES object has its reference count
1464:    decreased by one.

1466:    Level: developer

1468: .keywords: SNES, nonlinear, get, KSP, context

1470: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1471: @*/
1472: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1473: {

1480:   PetscObjectReference((PetscObject)ksp);
1481:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1482:   snes->ksp = ksp;
1483:   return(0);
1484: }

1486: /* -----------------------------------------------------------*/
1489: /*@
1490:    SNESCreate - Creates a nonlinear solver context.

1492:    Collective on MPI_Comm

1494:    Input Parameters:
1495: .  comm - MPI communicator

1497:    Output Parameter:
1498: .  outsnes - the new SNES context

1500:    Options Database Keys:
1501: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1502:                and no preconditioning matrix
1503: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1504:                products, and a user-provided preconditioning matrix
1505:                as set by SNESSetJacobian()
1506: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1508:    Level: beginner

1510: .keywords: SNES, nonlinear, create, context

1512: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner()

1514: @*/
1515: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1516: {
1518:   SNES           snes;
1519:   SNESKSPEW      *kctx;

1523:   *outsnes = NULL;
1524:   SNESInitializePackage();

1526:   PetscHeaderCreate(snes,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1528:   snes->ops->converged    = SNESConvergedDefault;
1529:   snes->usesksp           = PETSC_TRUE;
1530:   snes->tolerancesset     = PETSC_FALSE;
1531:   snes->max_its           = 50;
1532:   snes->max_funcs         = 10000;
1533:   snes->norm              = 0.0;
1534:   snes->normschedule      = SNES_NORM_ALWAYS;
1535:   snes->functype          = SNES_FUNCTION_DEFAULT;
1536: #if defined(PETSC_USE_REAL_SINGLE)
1537:   snes->rtol              = 1.e-5;
1538: #else
1539:   snes->rtol              = 1.e-8;
1540: #endif
1541:   snes->ttol              = 0.0;
1542: #if defined(PETSC_USE_REAL_SINGLE)
1543:   snes->abstol            = 1.e-25;
1544: #else
1545:   snes->abstol            = 1.e-50;
1546: #endif
1547: #if defined(PETSC_USE_REAL_SINGLE)
1548:   snes->stol              = 1.e-5;
1549: #else
1550:   snes->stol              = 1.e-8;
1551: #endif
1552: #if defined(PETSC_USE_REAL_SINGLE)
1553:   snes->deltatol          = 1.e-6;
1554: #else
1555:   snes->deltatol          = 1.e-12;
1556: #endif
1557:   snes->divtol            = 1.e4;
1558:   snes->rnorm0            = 0;
1559:   snes->nfuncs            = 0;
1560:   snes->numFailures       = 0;
1561:   snes->maxFailures       = 1;
1562:   snes->linear_its        = 0;
1563:   snes->lagjacobian       = 1;
1564:   snes->jac_iter          = 0;
1565:   snes->lagjac_persist    = PETSC_FALSE;
1566:   snes->lagpreconditioner = 1;
1567:   snes->pre_iter          = 0;
1568:   snes->lagpre_persist    = PETSC_FALSE;
1569:   snes->numbermonitors    = 0;
1570:   snes->data              = 0;
1571:   snes->setupcalled       = PETSC_FALSE;
1572:   snes->ksp_ewconv        = PETSC_FALSE;
1573:   snes->nwork             = 0;
1574:   snes->work              = 0;
1575:   snes->nvwork            = 0;
1576:   snes->vwork             = 0;
1577:   snes->conv_hist_len     = 0;
1578:   snes->conv_hist_max     = 0;
1579:   snes->conv_hist         = NULL;
1580:   snes->conv_hist_its     = NULL;
1581:   snes->conv_hist_reset   = PETSC_TRUE;
1582:   snes->counters_reset    = PETSC_TRUE;
1583:   snes->vec_func_init_set = PETSC_FALSE;
1584:   snes->reason            = SNES_CONVERGED_ITERATING;
1585:   snes->pcside            = PC_RIGHT;

1587:   snes->mf          = PETSC_FALSE;
1588:   snes->mf_operator = PETSC_FALSE;
1589:   snes->mf_version  = 1;

1591:   snes->numLinearSolveFailures = 0;
1592:   snes->maxLinearSolveFailures = 1;

1594:   snes->vizerotolerance = 1.e-8;

1596:   /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1597:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

1599:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1600:   PetscNewLog(snes,&kctx);

1602:   snes->kspconvctx  = (void*)kctx;
1603:   kctx->version     = 2;
1604:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1605:                              this was too large for some test cases */
1606:   kctx->rtol_last   = 0.0;
1607:   kctx->rtol_max    = .9;
1608:   kctx->gamma       = 1.0;
1609:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1610:   kctx->alpha2      = kctx->alpha;
1611:   kctx->threshold   = .1;
1612:   kctx->lresid_last = 0.0;
1613:   kctx->norm_last   = 0.0;

1615:   *outsnes = snes;
1616:   return(0);
1617: }

1619: /*MC
1620:     SNESFunction - Functional form used to convey the nonlinear function to be solved by SNES

1622:      Synopsis:
1623:      #include "petscsnes.h"
1624:      PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1626:      Input Parameters:
1627: +     snes - the SNES context
1628: .     x    - state at which to evaluate residual
1629: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1631:      Output Parameter:
1632: .     f  - vector to put residual (function value)

1634:    Level: intermediate

1636: .seealso:   SNESSetFunction(), SNESGetFunction()
1637: M*/

1641: /*@C
1642:    SNESSetFunction - Sets the function evaluation routine and function
1643:    vector for use by the SNES routines in solving systems of nonlinear
1644:    equations.

1646:    Logically Collective on SNES

1648:    Input Parameters:
1649: +  snes - the SNES context
1650: .  r - vector to store function value
1651: .  f - function evaluation routine; see SNESFunction for calling sequence details
1652: -  ctx - [optional] user-defined context for private data for the
1653:          function evaluation routine (may be NULL)

1655:    Notes:
1656:    The Newton-like methods typically solve linear systems of the form
1657: $      f'(x) x = -f(x),
1658:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1660:    Level: beginner

1662: .keywords: SNES, nonlinear, set, function

1664: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1665: @*/
1666: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1667: {
1669:   DM             dm;

1673:   if (r) {
1676:     PetscObjectReference((PetscObject)r);
1677:     VecDestroy(&snes->vec_func);

1679:     snes->vec_func = r;
1680:   }
1681:   SNESGetDM(snes,&dm);
1682:   DMSNESSetFunction(dm,f,ctx);
1683:   return(0);
1684: }


1689: /*@C
1690:    SNESSetInitialFunction - Sets the function vector to be used as the
1691:    function norm at the initialization of the method.  In some
1692:    instances, the user has precomputed the function before calling
1693:    SNESSolve.  This function allows one to avoid a redundant call
1694:    to SNESComputeFunction in that case.

1696:    Logically Collective on SNES

1698:    Input Parameters:
1699: +  snes - the SNES context
1700: -  f - vector to store function value

1702:    Notes:
1703:    This should not be modified during the solution procedure.

1705:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1707:    Level: developer

1709: .keywords: SNES, nonlinear, set, function

1711: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1712: @*/
1713: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1714: {
1716:   Vec            vec_func;

1722:   if (snes->pcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1723:     snes->vec_func_init_set = PETSC_FALSE;
1724:     return(0);
1725:   }
1726:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1727:   VecCopy(f, vec_func);

1729:   snes->vec_func_init_set = PETSC_TRUE;
1730:   return(0);
1731: }

1735: /*@
1736:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1737:    of the SNES method.

1739:    Logically Collective on SNES

1741:    Input Parameters:
1742: +  snes - the SNES context
1743: -  normschedule - the frequency of norm computation

1745:    Options Database Key:
1746: .  -snes_norm_schedule <none, always, initialonly, finalonly, initalfinalonly>

1748:    Notes:
1749:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1750:    of the nonlinear function and the taking of its norm at every iteration to
1751:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1752:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1753:    may either be monitored for convergence or not.  As these are often used as nonlinear
1754:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1755:    their solution.

1757:    Level: developer

1759: .keywords: SNES, nonlinear, set, function, norm, type

1761: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1762: @*/
1763: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1764: {
1767:   snes->normschedule = normschedule;
1768:   return(0);
1769: }


1774: /*@
1775:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1776:    of the SNES method.

1778:    Logically Collective on SNES

1780:    Input Parameters:
1781: +  snes - the SNES context
1782: -  normschedule - the type of the norm used

1784:    Level: advanced

1786: .keywords: SNES, nonlinear, set, function, norm, type

1788: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1789: @*/
1790: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1791: {
1794:   *normschedule = snes->normschedule;
1795:   return(0);
1796: }


1801: /*@
1802:   SNESSetFunctionNorm - Sets the last computed residual norm.

1804:   Logically Collective on SNES

1806:   Input Parameters:
1807: + snes - the SNES context

1809: - normschedule - the frequency of norm computation

1811:   Level: developer

1813: .keywords: SNES, nonlinear, set, function, norm, type
1814: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1815: @*/
1816: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
1817: {
1820:   snes->norm = norm;
1821:   return(0);
1822: }

1826: /*@
1827:   SNESGetFunctionNorm - Gets the last computed norm of the residual

1829:   Not Collective

1831:   Input Parameter:
1832: . snes - the SNES context

1834:   Output Parameter:
1835: . norm - the last computed residual norm

1837:   Level: developer

1839: .keywords: SNES, nonlinear, set, function, norm, type
1840: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1841: @*/
1842: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
1843: {
1847:   *norm = snes->norm;
1848:   return(0);
1849: }

1853: /*@C
1854:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
1855:    of the SNES method.

1857:    Logically Collective on SNES

1859:    Input Parameters:
1860: +  snes - the SNES context
1861: -  normschedule - the frequency of norm computation

1863:    Notes:
1864:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1865:    of the nonlinear function and the taking of its norm at every iteration to
1866:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1867:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1868:    may either be monitored for convergence or not.  As these are often used as nonlinear
1869:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1870:    their solution.

1872:    Level: developer

1874: .keywords: SNES, nonlinear, set, function, norm, type

1876: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1877: @*/
1878: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
1879: {
1882:   snes->functype = type;
1883:   return(0);
1884: }


1889: /*@C
1890:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
1891:    of the SNES method.

1893:    Logically Collective on SNES

1895:    Input Parameters:
1896: +  snes - the SNES context
1897: -  normschedule - the type of the norm used

1899:    Level: advanced

1901: .keywords: SNES, nonlinear, set, function, norm, type

1903: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1904: @*/
1905: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
1906: {
1909:   *type = snes->functype;
1910:   return(0);
1911: }

1913: /*MC
1914:     SNESNGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

1916:      Synopsis:
1917:      #include <petscsnes.h>
1918: $    SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);

1920: +  X   - solution vector
1921: .  B   - RHS vector
1922: -  ctx - optional user-defined Gauss-Seidel context

1924:    Level: intermediate

1926: .seealso:   SNESSetNGS(), SNESGetNGS()
1927: M*/

1931: /*@C
1932:    SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
1933:    use with composed nonlinear solvers.

1935:    Input Parameters:
1936: +  snes   - the SNES context
1937: .  f - function evaluation routine to apply Gauss-Seidel see SNESNGSFunction
1938: -  ctx    - [optional] user-defined context for private data for the
1939:             smoother evaluation routine (may be NULL)

1941:    Notes:
1942:    The NGS routines are used by the composed nonlinear solver to generate
1943:     a problem appropriate update to the solution, particularly FAS.

1945:    Level: intermediate

1947: .keywords: SNES, nonlinear, set, Gauss-Seidel

1949: .seealso: SNESGetFunction(), SNESComputeNGS()
1950: @*/
1951: PetscErrorCode SNESSetNGS(SNES snes,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1952: {
1954:   DM             dm;

1958:   SNESGetDM(snes,&dm);
1959:   DMSNESSetNGS(dm,f,ctx);
1960:   return(0);
1961: }

1965: PETSC_EXTERN PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
1966: {
1968:   DM             dm;
1969:   DMSNES         sdm;

1972:   SNESGetDM(snes,&dm);
1973:   DMGetDMSNES(dm,&sdm);
1974:   /*  A(x)*x - b(x) */
1975:   if (sdm->ops->computepfunction) {
1976:     (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
1977:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");

1979:   if (sdm->ops->computepjacobian) {
1980:     (*sdm->ops->computepjacobian)(snes,x,snes->jacobian,snes->jacobian_pre,sdm->pctx);
1981:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard matrix.");
1982:   VecScale(f,-1.0);
1983:   MatMultAdd(snes->jacobian,x,f,f);
1984:   return(0);
1985: }

1989: PETSC_EXTERN PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat J,Mat B,void *ctx)
1990: {
1992:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
1993:   return(0);
1994: }

1998: /*@C
1999:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

2001:    Logically Collective on SNES

2003:    Input Parameters:
2004: +  snes - the SNES context
2005: .  r - vector to store function value
2006: .  b - function evaluation routine
2007: .  Amat - matrix with which A(x) x - b(x) is to be computed
2008: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
2009: .  J  - function to compute matrix value, see SNESJacobianFunction for details on its calling sequence
2010: -  ctx - [optional] user-defined context for private data for the
2011:          function evaluation routine (may be NULL)

2013:    Notes:
2014:     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
2015:     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.

2017:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

2019: $     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}
2020: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

2022:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

2024:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2025:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

2027:    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
2028:    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
2029:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

2031:    Level: intermediate

2033: .keywords: SNES, nonlinear, set, function

2035: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard(), SNESJacobianFunction
2036: @*/
2037: 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)
2038: {
2040:   DM             dm;

2044:   SNESGetDM(snes, &dm);
2045:   DMSNESSetPicard(dm,b,J,ctx);
2046:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
2047:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
2048:   return(0);
2049: }

2053: /*@C
2054:    SNESGetPicard - Returns the context for the Picard iteration

2056:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

2058:    Input Parameter:
2059: .  snes - the SNES context

2061:    Output Parameter:
2062: +  r - the function (or NULL)
2063: .  f - the function (or NULL); see SNESFunction for calling sequence details
2064: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
2065: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
2066: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
2067: -  ctx - the function context (or NULL)

2069:    Level: advanced

2071: .keywords: SNES, nonlinear, get, function

2073: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
2074: @*/
2075: 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)
2076: {
2078:   DM             dm;

2082:   SNESGetFunction(snes,r,NULL,NULL);
2083:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
2084:   SNESGetDM(snes,&dm);
2085:   DMSNESGetPicard(dm,f,J,ctx);
2086:   return(0);
2087: }

2091: /*@C
2092:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

2094:    Logically Collective on SNES

2096:    Input Parameters:
2097: +  snes - the SNES context
2098: .  func - function evaluation routine
2099: -  ctx - [optional] user-defined context for private data for the
2100:          function evaluation routine (may be NULL)

2102:    Calling sequence of func:
2103: $    func (SNES snes,Vec x,void *ctx);

2105: .  f - function vector
2106: -  ctx - optional user-defined function context

2108:    Level: intermediate

2110: .keywords: SNES, nonlinear, set, function

2112: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
2113: @*/
2114: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
2115: {
2118:   if (func) snes->ops->computeinitialguess = func;
2119:   if (ctx)  snes->initialguessP            = ctx;
2120:   return(0);
2121: }

2123: /* --------------------------------------------------------------- */
2126: /*@C
2127:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
2128:    it assumes a zero right hand side.

2130:    Logically Collective on SNES

2132:    Input Parameter:
2133: .  snes - the SNES context

2135:    Output Parameter:
2136: .  rhs - the right hand side vector or NULL if the right hand side vector is null

2138:    Level: intermediate

2140: .keywords: SNES, nonlinear, get, function, right hand side

2142: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2143: @*/
2144: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2145: {
2149:   *rhs = snes->vec_rhs;
2150:   return(0);
2151: }

2155: /*@
2156:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2158:    Collective on SNES

2160:    Input Parameters:
2161: +  snes - the SNES context
2162: -  x - input vector

2164:    Output Parameter:
2165: .  y - function vector, as set by SNESSetFunction()

2167:    Notes:
2168:    SNESComputeFunction() is typically used within nonlinear solvers
2169:    implementations, so most users would not generally call this routine
2170:    themselves.

2172:    Level: developer

2174: .keywords: SNES, nonlinear, compute, function

2176: .seealso: SNESSetFunction(), SNESGetFunction()
2177: @*/
2178: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2179: {
2181:   DM             dm;
2182:   DMSNES         sdm;

2190:   VecValidValues(x,2,PETSC_TRUE);

2192:   SNESGetDM(snes,&dm);
2193:   DMGetDMSNES(dm,&sdm);
2194:   if (sdm->ops->computefunction) {
2195:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2196:       PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2197:     }
2198:     VecLockPush(x);
2199:     PetscStackPush("SNES user function");
2200:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2201:     PetscStackPop;
2202:     VecLockPop(x);
2203:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2204:       PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2205:     }
2206:   } else if (snes->vec_rhs) {
2207:     MatMult(snes->jacobian, x, y);
2208:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2209:   if (snes->vec_rhs) {
2210:     VecAXPY(y,-1.0,snes->vec_rhs);
2211:   }
2212:   snes->nfuncs++;
2213:   /*
2214:      domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2215:      propagate the value to all processes
2216:   */
2217:   if (snes->domainerror) {
2218:     VecSetInf(y);
2219:   }
2220:   return(0);
2221: }

2225: /*@
2226:    SNESComputeNGS - Calls the Gauss-Seidel function that has been set with  SNESSetNGS().

2228:    Collective on SNES

2230:    Input Parameters:
2231: +  snes - the SNES context
2232: .  x - input vector
2233: -  b - rhs vector

2235:    Output Parameter:
2236: .  x - new solution vector

2238:    Notes:
2239:    SNESComputeNGS() is typically used within composed nonlinear solver
2240:    implementations, so most users would not generally call this routine
2241:    themselves.

2243:    Level: developer

2245: .keywords: SNES, nonlinear, compute, function

2247: .seealso: SNESSetNGS(), SNESComputeFunction()
2248: @*/
2249: PetscErrorCode  SNESComputeNGS(SNES snes,Vec b,Vec x)
2250: {
2252:   DM             dm;
2253:   DMSNES         sdm;

2261:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2262:   PetscLogEventBegin(SNES_NGSEval,snes,x,b,0);
2263:   SNESGetDM(snes,&dm);
2264:   DMGetDMSNES(dm,&sdm);
2265:   if (sdm->ops->computegs) {
2266:     if (b) {VecLockPush(b);}
2267:     PetscStackPush("SNES user NGS");
2268:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2269:     PetscStackPop;
2270:     if (b) {VecLockPop(b);}
2271:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2272:   PetscLogEventEnd(SNES_NGSEval,snes,x,b,0);
2273:   return(0);
2274: }

2278: /*@
2279:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2281:    Collective on SNES and Mat

2283:    Input Parameters:
2284: +  snes - the SNES context
2285: -  x - input vector

2287:    Output Parameters:
2288: +  A - Jacobian matrix
2289: -  B - optional preconditioning matrix

2291:   Options Database Keys:
2292: +    -snes_lag_preconditioner <lag>
2293: .    -snes_lag_jacobian <lag>
2294: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2295: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2296: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2297: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2298: .    -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2299: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2300: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2301: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2302: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2303: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2304: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2307:    Notes:
2308:    Most users should not need to explicitly call this routine, as it
2309:    is used internally within the nonlinear solvers.

2311:    Level: developer

2313: .keywords: SNES, compute, Jacobian, matrix

2315: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2316: @*/
2317: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat A,Mat B)
2318: {
2320:   PetscBool      flag;
2321:   DM             dm;
2322:   DMSNES         sdm;
2323:   KSP            ksp;

2329:   VecValidValues(X,2,PETSC_TRUE);
2330:   SNESGetDM(snes,&dm);
2331:   DMGetDMSNES(dm,&sdm);

2333:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2335:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2337:   if (snes->lagjacobian == -2) {
2338:     snes->lagjacobian = -1;

2340:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2341:   } else if (snes->lagjacobian == -1) {
2342:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2343:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2344:     if (flag) {
2345:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2346:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2347:     }
2348:     return(0);
2349:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2350:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2351:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2352:     if (flag) {
2353:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2354:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2355:     }
2356:     return(0);
2357:   }
2358:   if (snes->pc && snes->pcside == PC_LEFT) {
2359:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2360:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2361:       return(0);
2362:   }

2364:   PetscLogEventBegin(SNES_JacobianEval,snes,X,A,B);
2365:   VecLockPush(X);
2366:   PetscStackPush("SNES user Jacobian function");
2367:   (*sdm->ops->computejacobian)(snes,X,A,B,sdm->jacobianctx);
2368:   PetscStackPop;
2369:   VecLockPop(X);
2370:   PetscLogEventEnd(SNES_JacobianEval,snes,X,A,B);

2372:   /* the next line ensures that snes->ksp exists */
2373:   SNESGetKSP(snes,&ksp);
2374:   if (snes->lagpreconditioner == -2) {
2375:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");
2376:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2377:     snes->lagpreconditioner = -1;
2378:   } else if (snes->lagpreconditioner == -1) {
2379:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2380:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2381:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2382:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2383:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2384:   } else {
2385:     PetscInfo(snes,"Rebuilding preconditioner\n");
2386:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2387:   }

2389:   /* make sure user returned a correct Jacobian and preconditioner */
2392:   {
2393:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2394:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_explicit",NULL,NULL,&flag);
2395:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",NULL,NULL,&flag_draw);
2396:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",NULL,NULL,&flag_contour);
2397:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_operator",NULL,NULL,&flag_operator);
2398:     if (flag || flag_draw || flag_contour) {
2399:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2400:       PetscViewer  vdraw,vstdout;
2401:       PetscBool    flg;
2402:       if (flag_operator) {
2403:         MatComputeExplicitOperator(A,&Bexp_mine);
2404:         Bexp = Bexp_mine;
2405:       } else {
2406:         /* See if the preconditioning matrix can be viewed and added directly */
2407:         PetscObjectTypeCompareAny((PetscObject)B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2408:         if (flg) Bexp = B;
2409:         else {
2410:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2411:           MatComputeExplicitOperator(B,&Bexp_mine);
2412:           Bexp = Bexp_mine;
2413:         }
2414:       }
2415:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2416:       SNESComputeJacobianDefault(snes,X,FDexp,FDexp,NULL);
2417:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2418:       if (flag_draw || flag_contour) {
2419:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2420:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2421:       } else vdraw = NULL;
2422:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2423:       if (flag) {MatView(Bexp,vstdout);}
2424:       if (vdraw) {MatView(Bexp,vdraw);}
2425:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2426:       if (flag) {MatView(FDexp,vstdout);}
2427:       if (vdraw) {MatView(FDexp,vdraw);}
2428:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2429:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2430:       if (flag) {MatView(FDexp,vstdout);}
2431:       if (vdraw) {              /* Always use contour for the difference */
2432:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2433:         MatView(FDexp,vdraw);
2434:         PetscViewerPopFormat(vdraw);
2435:       }
2436:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2437:       PetscViewerDestroy(&vdraw);
2438:       MatDestroy(&Bexp_mine);
2439:       MatDestroy(&FDexp);
2440:     }
2441:   }
2442:   {
2443:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2444:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2445:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring",NULL,NULL,&flag);
2446:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_display",NULL,NULL,&flag_display);
2447:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",NULL,NULL,&flag_draw);
2448:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",NULL,NULL,&flag_contour);
2449:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",NULL,NULL,&flag_threshold);
2450:     if (flag_threshold) {
2451:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2452:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2453:     }
2454:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2455:       Mat            Bfd;
2456:       PetscViewer    vdraw,vstdout;
2457:       MatColoring    coloring;
2458:       ISColoring     iscoloring;
2459:       MatFDColoring  matfdcoloring;
2460:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2461:       void           *funcctx;
2462:       PetscReal      norm1,norm2,normmax;

2464:       MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2465:       MatColoringCreate(Bfd,&coloring);
2466:       MatColoringSetType(coloring,MATCOLORINGSL);
2467:       MatColoringSetFromOptions(coloring);
2468:       MatColoringApply(coloring,&iscoloring);
2469:       MatColoringDestroy(&coloring);
2470:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2471:       MatFDColoringSetFromOptions(matfdcoloring);
2472:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2473:       ISColoringDestroy(&iscoloring);

2475:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2476:       SNESGetFunction(snes,NULL,&func,&funcctx);
2477:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2478:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2479:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2480:       MatFDColoringSetFromOptions(matfdcoloring);
2481:       MatFDColoringApply(Bfd,matfdcoloring,X,snes);
2482:       MatFDColoringDestroy(&matfdcoloring);

2484:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2485:       if (flag_draw || flag_contour) {
2486:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2487:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2488:       } else vdraw = NULL;
2489:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2490:       if (flag_display) {MatView(B,vstdout);}
2491:       if (vdraw) {MatView(B,vdraw);}
2492:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2493:       if (flag_display) {MatView(Bfd,vstdout);}
2494:       if (vdraw) {MatView(Bfd,vdraw);}
2495:       MatAYPX(Bfd,-1.0,B,SAME_NONZERO_PATTERN);
2496:       MatNorm(Bfd,NORM_1,&norm1);
2497:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2498:       MatNorm(Bfd,NORM_MAX,&normmax);
2499:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2500:       if (flag_display) {MatView(Bfd,vstdout);}
2501:       if (vdraw) {              /* Always use contour for the difference */
2502:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2503:         MatView(Bfd,vdraw);
2504:         PetscViewerPopFormat(vdraw);
2505:       }
2506:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2508:       if (flag_threshold) {
2509:         PetscInt bs,rstart,rend,i;
2510:         MatGetBlockSize(B,&bs);
2511:         MatGetOwnershipRange(B,&rstart,&rend);
2512:         for (i=rstart; i<rend; i++) {
2513:           const PetscScalar *ba,*ca;
2514:           const PetscInt    *bj,*cj;
2515:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2516:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2517:           MatGetRow(B,i,&bn,&bj,&ba);
2518:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2519:           if (bn != cn) SETERRQ(((PetscObject)A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2520:           for (j=0; j<bn; j++) {
2521:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2522:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2523:               maxentrycol = bj[j];
2524:               maxentry    = PetscRealPart(ba[j]);
2525:             }
2526:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2527:               maxdiffcol = bj[j];
2528:               maxdiff    = PetscRealPart(ca[j]);
2529:             }
2530:             if (rdiff > maxrdiff) {
2531:               maxrdiffcol = bj[j];
2532:               maxrdiff    = rdiff;
2533:             }
2534:           }
2535:           if (maxrdiff > 1) {
2536:             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);
2537:             for (j=0; j<bn; j++) {
2538:               PetscReal rdiff;
2539:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2540:               if (rdiff > 1) {
2541:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2542:               }
2543:             }
2544:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2545:           }
2546:           MatRestoreRow(B,i,&bn,&bj,&ba);
2547:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2548:         }
2549:       }
2550:       PetscViewerDestroy(&vdraw);
2551:       MatDestroy(&Bfd);
2552:     }
2553:   }
2554:   return(0);
2555: }

2557: /*MC
2558:     SNESJacobianFunction - Function used to convey the nonlinear Jacobian of the function to be solved by SNES

2560:      Synopsis:
2561:      #include "petscsnes.h"
2562:      PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);

2564: +  x - input vector
2565: .  Amat - the matrix that defines the (approximate) Jacobian
2566: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2567: -  ctx - [optional] user-defined Jacobian context

2569:    Level: intermediate

2571: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2572: M*/

2576: /*@C
2577:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2578:    location to store the matrix.

2580:    Logically Collective on SNES and Mat

2582:    Input Parameters:
2583: +  snes - the SNES context
2584: .  Amat - the matrix that defines the (approximate) Jacobian
2585: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2586: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value), see SNESJacobianFunction for details
2587: -  ctx - [optional] user-defined context for private data for the
2588:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2590:    Notes:
2591:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2592:    each matrix.

2594:    If you know the operator Amat has a null space you can use MatSetNullSpace() and MatSetTransposeNullSpace() to supply the null
2595:    space to Amat and the KSP solvers will automatically use that null space as needed during the solution process.

2597:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2598:    must be a MatFDColoring.

2600:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2601:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2603:    Level: beginner

2605: .keywords: SNES, nonlinear, set, Jacobian, matrix

2607: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J, 
2608:           SNESSetPicard(), SNESJacobianFunction
2609: @*/
2610: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2611: {
2613:   DM             dm;

2621:   SNESGetDM(snes,&dm);
2622:   DMSNESSetJacobian(dm,J,ctx);
2623:   if (Amat) {
2624:     PetscObjectReference((PetscObject)Amat);
2625:     MatDestroy(&snes->jacobian);

2627:     snes->jacobian = Amat;
2628:   }
2629:   if (Pmat) {
2630:     PetscObjectReference((PetscObject)Pmat);
2631:     MatDestroy(&snes->jacobian_pre);

2633:     snes->jacobian_pre = Pmat;
2634:   }
2635:   return(0);
2636: }

2640: /*@C
2641:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2642:    provided context for evaluating the Jacobian.

2644:    Not Collective, but Mat object will be parallel if SNES object is

2646:    Input Parameter:
2647: .  snes - the nonlinear solver context

2649:    Output Parameters:
2650: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
2651: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
2652: .  J - location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
2653: -  ctx - location to stash Jacobian ctx (or NULL)

2655:    Level: advanced

2657: .seealso: SNESSetJacobian(), SNESComputeJacobian(), SNESJacobianFunction, SNESGetFunction()
2658: @*/
2659: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
2660: {
2662:   DM             dm;
2663:   DMSNES         sdm;

2667:   if (Amat) *Amat = snes->jacobian;
2668:   if (Pmat) *Pmat = snes->jacobian_pre;
2669:   SNESGetDM(snes,&dm);
2670:   DMGetDMSNES(dm,&sdm);
2671:   if (J) *J = sdm->ops->computejacobian;
2672:   if (ctx) *ctx = sdm->jacobianctx;
2673:   return(0);
2674: }

2678: /*@
2679:    SNESSetUp - Sets up the internal data structures for the later use
2680:    of a nonlinear solver.

2682:    Collective on SNES

2684:    Input Parameters:
2685: .  snes - the SNES context

2687:    Notes:
2688:    For basic use of the SNES solvers the user need not explicitly call
2689:    SNESSetUp(), since these actions will automatically occur during
2690:    the call to SNESSolve().  However, if one wishes to control this
2691:    phase separately, SNESSetUp() should be called after SNESCreate()
2692:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

2694:    Level: advanced

2696: .keywords: SNES, nonlinear, setup

2698: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
2699: @*/
2700: PetscErrorCode  SNESSetUp(SNES snes)
2701: {
2703:   DM             dm;
2704:   DMSNES         sdm;
2705:   SNESLineSearch linesearch, pclinesearch;
2706:   void           *lsprectx,*lspostctx;
2707:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
2708:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
2709:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2710:   Vec            f,fpc;
2711:   void           *funcctx;
2712:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
2713:   void           *jacctx,*appctx;
2714:   Mat            j,jpre;

2718:   if (snes->setupcalled) return(0);

2720:   if (!((PetscObject)snes)->type_name) {
2721:     SNESSetType(snes,SNESNEWTONLS);
2722:   }

2724:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

2726:   SNESGetDM(snes,&dm);
2727:   DMGetDMSNES(dm,&sdm);
2728:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
2729:   if (!sdm->ops->computejacobian) {
2730:     DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
2731:   }
2732:   if (!snes->vec_func) {
2733:     DMCreateGlobalVector(dm,&snes->vec_func);
2734:   }

2736:   if (!snes->ksp) {
2737:     SNESGetKSP(snes, &snes->ksp);
2738:   }

2740:   if (!snes->linesearch) {
2741:     SNESGetLineSearch(snes, &snes->linesearch);
2742:   }
2743:   SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);

2745:   if (snes->pc && (snes->pcside == PC_LEFT)) {
2746:     snes->mf          = PETSC_TRUE;
2747:     snes->mf_operator = PETSC_FALSE;
2748:   }

2750:   if (snes->pc) {
2751:     /* copy the DM over */
2752:     SNESGetDM(snes,&dm);
2753:     SNESSetDM(snes->pc,dm);

2755:     SNESGetFunction(snes,&f,&func,&funcctx);
2756:     VecDuplicate(f,&fpc);
2757:     SNESSetFunction(snes->pc,fpc,func,funcctx);
2758:     SNESGetJacobian(snes,&j,&jpre,&jac,&jacctx);
2759:     SNESSetJacobian(snes->pc,j,jpre,jac,jacctx);
2760:     SNESGetApplicationContext(snes,&appctx);
2761:     SNESSetApplicationContext(snes->pc,appctx);
2762:     VecDestroy(&fpc);

2764:     /* copy the function pointers over */
2765:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->pc);

2767:     /* default to 1 iteration */
2768:     SNESSetTolerances(snes->pc,0.0,0.0,0.0,1,snes->pc->max_funcs);
2769:     if (snes->pcside==PC_RIGHT) {
2770:       SNESSetNormSchedule(snes->pc,SNES_NORM_FINAL_ONLY);
2771:     } else {
2772:       SNESSetNormSchedule(snes->pc,SNES_NORM_NONE);
2773:     }
2774:     SNESSetFromOptions(snes->pc);

2776:     /* copy the line search context over */
2777:     SNESGetLineSearch(snes,&linesearch);
2778:     SNESGetLineSearch(snes->pc,&pclinesearch);
2779:     SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
2780:     SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
2781:     SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
2782:     SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
2783:     PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
2784:   }
2785:   if (snes->mf) {
2786:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
2787:   }
2788:   if (snes->ops->usercompute && !snes->user) {
2789:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
2790:   }

2792:   snes->jac_iter = 0;
2793:   snes->pre_iter = 0;

2795:   if (snes->ops->setup) {
2796:     (*snes->ops->setup)(snes);
2797:   }

2799:   if (snes->pc && (snes->pcside == PC_LEFT)) {
2800:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
2801:       SNESGetLineSearch(snes,&linesearch);
2802:       SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultNPC);
2803:     }
2804:   }

2806:   snes->setupcalled = PETSC_TRUE;
2807:   return(0);
2808: }

2812: /*@
2813:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

2815:    Collective on SNES

2817:    Input Parameter:
2818: .  snes - iterative context obtained from SNESCreate()

2820:    Level: intermediate

2822:    Notes: Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

2824: .keywords: SNES, destroy

2826: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
2827: @*/
2828: PetscErrorCode  SNESReset(SNES snes)
2829: {

2834:   if (snes->ops->userdestroy && snes->user) {
2835:     (*snes->ops->userdestroy)((void**)&snes->user);
2836:     snes->user = NULL;
2837:   }
2838:   if (snes->pc) {
2839:     SNESReset(snes->pc);
2840:   }

2842:   if (snes->ops->reset) {
2843:     (*snes->ops->reset)(snes);
2844:   }
2845:   if (snes->ksp) {
2846:     KSPReset(snes->ksp);
2847:   }

2849:   if (snes->linesearch) {
2850:     SNESLineSearchReset(snes->linesearch);
2851:   }

2853:   VecDestroy(&snes->vec_rhs);
2854:   VecDestroy(&snes->vec_sol);
2855:   VecDestroy(&snes->vec_sol_update);
2856:   VecDestroy(&snes->vec_func);
2857:   MatDestroy(&snes->jacobian);
2858:   MatDestroy(&snes->jacobian_pre);
2859:   VecDestroyVecs(snes->nwork,&snes->work);
2860:   VecDestroyVecs(snes->nvwork,&snes->vwork);

2862:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

2864:   snes->nwork       = snes->nvwork = 0;
2865:   snes->setupcalled = PETSC_FALSE;
2866:   return(0);
2867: }

2871: /*@
2872:    SNESDestroy - Destroys the nonlinear solver context that was created
2873:    with SNESCreate().

2875:    Collective on SNES

2877:    Input Parameter:
2878: .  snes - the SNES context

2880:    Level: beginner

2882: .keywords: SNES, nonlinear, destroy

2884: .seealso: SNESCreate(), SNESSolve()
2885: @*/
2886: PetscErrorCode  SNESDestroy(SNES *snes)
2887: {

2891:   if (!*snes) return(0);
2893:   if (--((PetscObject)(*snes))->refct > 0) {*snes = 0; return(0);}

2895:   SNESReset((*snes));
2896:   SNESDestroy(&(*snes)->pc);

2898:   /* if memory was published with SAWs then destroy it */
2899:   PetscObjectSAWsViewOff((PetscObject)*snes);
2900:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

2902:   DMDestroy(&(*snes)->dm);
2903:   KSPDestroy(&(*snes)->ksp);
2904:   SNESLineSearchDestroy(&(*snes)->linesearch);

2906:   PetscFree((*snes)->kspconvctx);
2907:   if ((*snes)->ops->convergeddestroy) {
2908:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
2909:   }
2910:   if ((*snes)->conv_malloc) {
2911:     PetscFree((*snes)->conv_hist);
2912:     PetscFree((*snes)->conv_hist_its);
2913:   }
2914:   SNESMonitorCancel((*snes));
2915:   PetscHeaderDestroy(snes);
2916:   return(0);
2917: }

2919: /* ----------- Routines to set solver parameters ---------- */

2923: /*@
2924:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

2926:    Logically Collective on SNES

2928:    Input Parameters:
2929: +  snes - the SNES context
2930: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2931:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

2933:    Options Database Keys:
2934: .    -snes_lag_preconditioner <lag>

2936:    Notes:
2937:    The default is 1
2938:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
2939:    If  -1 is used before the very first nonlinear solve the preconditioner is still built because there is no previous preconditioner to use

2941:    Level: intermediate

2943: .keywords: SNES, nonlinear, set, convergence, tolerances

2945: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian()

2947: @*/
2948: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
2949: {
2952:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
2953:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
2955:   snes->lagpreconditioner = lag;
2956:   return(0);
2957: }

2961: /*@
2962:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

2964:    Logically Collective on SNES

2966:    Input Parameters:
2967: +  snes - the SNES context
2968: -  steps - the number of refinements to do, defaults to 0

2970:    Options Database Keys:
2971: .    -snes_grid_sequence <steps>

2973:    Level: intermediate

2975:    Notes:
2976:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

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

2980: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetGridSequence()

2982: @*/
2983: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
2984: {
2988:   snes->gridsequence = steps;
2989:   return(0);
2990: }

2994: /*@
2995:    SNESGetGridSequence - gets the number of steps of grid sequencing that SNES does

2997:    Logically Collective on SNES

2999:    Input Parameter:
3000: .  snes - the SNES context

3002:    Output Parameter:
3003: .  steps - the number of refinements to do, defaults to 0

3005:    Options Database Keys:
3006: .    -snes_grid_sequence <steps>

3008:    Level: intermediate

3010:    Notes:
3011:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3013: .keywords: SNES, nonlinear, set, convergence, tolerances

3015: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetGridSequence()

3017: @*/
3018: PetscErrorCode  SNESGetGridSequence(SNES snes,PetscInt *steps)
3019: {
3022:   *steps = snes->gridsequence;
3023:   return(0);
3024: }

3028: /*@
3029:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

3031:    Not Collective

3033:    Input Parameter:
3034: .  snes - the SNES context

3036:    Output Parameter:
3037: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3038:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3040:    Options Database Keys:
3041: .    -snes_lag_preconditioner <lag>

3043:    Notes:
3044:    The default is 1
3045:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3047:    Level: intermediate

3049: .keywords: SNES, nonlinear, set, convergence, tolerances

3051: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner()

3053: @*/
3054: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
3055: {
3058:   *lag = snes->lagpreconditioner;
3059:   return(0);
3060: }

3064: /*@
3065:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
3066:      often the preconditioner is rebuilt.

3068:    Logically Collective on SNES

3070:    Input Parameters:
3071: +  snes - the SNES context
3072: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3073:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

3075:    Options Database Keys:
3076: .    -snes_lag_jacobian <lag>

3078:    Notes:
3079:    The default is 1
3080:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3081:    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
3082:    at the next Newton step but never again (unless it is reset to another value)

3084:    Level: intermediate

3086: .keywords: SNES, nonlinear, set, convergence, tolerances

3088: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobian()

3090: @*/
3091: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
3092: {
3095:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3096:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3098:   snes->lagjacobian = lag;
3099:   return(0);
3100: }

3104: /*@
3105:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

3107:    Not Collective

3109:    Input Parameter:
3110: .  snes - the SNES context

3112:    Output Parameter:
3113: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3114:          the Jacobian is built etc.

3116:    Options Database Keys:
3117: .    -snes_lag_jacobian <lag>

3119:    Notes:
3120:    The default is 1
3121:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3123:    Level: intermediate

3125: .keywords: SNES, nonlinear, set, convergence, tolerances

3127: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner()

3129: @*/
3130: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
3131: {
3134:   *lag = snes->lagjacobian;
3135:   return(0);
3136: }

3140: /*@
3141:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

3143:    Logically collective on SNES

3145:    Input Parameter:
3146: +  snes - the SNES context
3147: -   flg - jacobian lagging persists if true

3149:    Options Database Keys:
3150: .    -snes_lag_jacobian_persists <flg>

3152:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3153:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3154:    timesteps may present huge efficiency gains.

3156:    Level: developer

3158: .keywords: SNES, nonlinear, lag

3160: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3162: @*/
3163: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3164: {
3168:   snes->lagjac_persist = flg;
3169:   return(0);
3170: }

3174: /*@
3175:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple solves

3177:    Logically Collective on SNES

3179:    Input Parameter:
3180: +  snes - the SNES context
3181: -   flg - preconditioner lagging persists if true

3183:    Options Database Keys:
3184: .    -snes_lag_jacobian_persists <flg>

3186:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3187:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3188:    several timesteps may present huge efficiency gains.

3190:    Level: developer

3192: .keywords: SNES, nonlinear, lag

3194: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3196: @*/
3197: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3198: {
3202:   snes->lagpre_persist = flg;
3203:   return(0);
3204: }

3208: /*@
3209:    SNESSetTolerances - Sets various parameters used in convergence tests.

3211:    Logically Collective on SNES

3213:    Input Parameters:
3214: +  snes - the SNES context
3215: .  abstol - absolute convergence tolerance
3216: .  rtol - relative convergence tolerance
3217: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3218: .  maxit - maximum number of iterations
3219: -  maxf - maximum number of function evaluations

3221:    Options Database Keys:
3222: +    -snes_atol <abstol> - Sets abstol
3223: .    -snes_rtol <rtol> - Sets rtol
3224: .    -snes_stol <stol> - Sets stol
3225: .    -snes_max_it <maxit> - Sets maxit
3226: -    -snes_max_funcs <maxf> - Sets maxf

3228:    Notes:
3229:    The default maximum number of iterations is 50.
3230:    The default maximum number of function evaluations is 1000.

3232:    Level: intermediate

3234: .keywords: SNES, nonlinear, set, convergence, tolerances

3236: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3237: @*/
3238: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3239: {

3248:   if (abstol != PETSC_DEFAULT) {
3249:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3250:     snes->abstol = abstol;
3251:   }
3252:   if (rtol != PETSC_DEFAULT) {
3253:     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);
3254:     snes->rtol = rtol;
3255:   }
3256:   if (stol != PETSC_DEFAULT) {
3257:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3258:     snes->stol = stol;
3259:   }
3260:   if (maxit != PETSC_DEFAULT) {
3261:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3262:     snes->max_its = maxit;
3263:   }
3264:   if (maxf != PETSC_DEFAULT) {
3265:     if (maxf < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be non-negative",maxf);
3266:     snes->max_funcs = maxf;
3267:   }
3268:   snes->tolerancesset = PETSC_TRUE;
3269:   return(0);
3270: }

3274: /*@
3275:    SNESSetDivergenceTolerance - Sets the divergence tolerance used for the SNES divergence test.

3277:    Logically Collective on SNES

3279:    Input Parameters:
3280: +  snes - the SNES context
3281: -  divtol - the divergence tolerance. Use -1 to deactivate the test.

3283:    Options Database Keys:
3284: +    -snes_divergence_tolerance <divtol> - Sets divtol

3286:    Notes:
3287:    The default divergence tolerance is 1e4.

3289:    Level: intermediate

3291: .keywords: SNES, nonlinear, set, divergence, tolerance

3293: .seealso: SNESSetTolerances(), SNESGetDivergenceTolerance
3294: @*/
3295: PetscErrorCode  SNESSetDivergenceTolerance(SNES snes,PetscReal divtol)
3296: {

3301:   if (divtol != PETSC_DEFAULT) {
3302:     snes->divtol = divtol;
3303:   }
3304:   else {
3305:     snes->divtol = 1.0e4;
3306:   }
3307:   return(0);
3308: }

3312: /*@
3313:    SNESGetTolerances - Gets various parameters used in convergence tests.

3315:    Not Collective

3317:    Input Parameters:
3318: +  snes - the SNES context
3319: .  atol - absolute convergence tolerance
3320: .  rtol - relative convergence tolerance
3321: .  stol -  convergence tolerance in terms of the norm
3322:            of the change in the solution between steps
3323: .  maxit - maximum number of iterations
3324: -  maxf - maximum number of function evaluations

3326:    Notes:
3327:    The user can specify NULL for any parameter that is not needed.

3329:    Level: intermediate

3331: .keywords: SNES, nonlinear, get, convergence, tolerances

3333: .seealso: SNESSetTolerances()
3334: @*/
3335: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3336: {
3339:   if (atol)  *atol  = snes->abstol;
3340:   if (rtol)  *rtol  = snes->rtol;
3341:   if (stol)  *stol  = snes->stol;
3342:   if (maxit) *maxit = snes->max_its;
3343:   if (maxf)  *maxf  = snes->max_funcs;
3344:   return(0);
3345: }

3349: /*@
3350:    SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.

3352:    Not Collective

3354:    Input Parameters:
3355: +  snes - the SNES context
3356: -  divtol - divergence tolerance

3358:    Level: intermediate

3360: .keywords: SNES, nonlinear, get, divergence, tolerance

3362: .seealso: SNESSetDivergenceTolerance()
3363: @*/
3364: PetscErrorCode  SNESGetDivergenceTolerance(SNES snes,PetscReal *divtol)
3365: {
3368:   if (divtol) *divtol = snes->divtol;
3369:   return(0);
3370: }

3374: /*@
3375:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3377:    Logically Collective on SNES

3379:    Input Parameters:
3380: +  snes - the SNES context
3381: -  tol - tolerance

3383:    Options Database Key:
3384: .  -snes_trtol <tol> - Sets tol

3386:    Level: intermediate

3388: .keywords: SNES, nonlinear, set, trust region, tolerance

3390: .seealso: SNESSetTolerances()
3391: @*/
3392: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3393: {
3397:   snes->deltatol = tol;
3398:   return(0);
3399: }

3401: /*
3402:    Duplicate the lg monitors for SNES from KSP; for some reason with
3403:    dynamic libraries things don't work under Sun4 if we just use
3404:    macros instead of functions
3405: */
3408: PetscErrorCode  SNESMonitorLGResidualNorm(SNES snes,PetscInt it,PetscReal norm,void *ctx)
3409: {

3414:   KSPMonitorLGResidualNorm((KSP)snes,it,norm,ctx);
3415:   return(0);
3416: }

3420: PetscErrorCode  SNESMonitorLGCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscDrawLG *lgctx)
3421: {

3425:   KSPMonitorLGResidualNormCreate(comm,host,label,x,y,m,n,lgctx);
3426:   return(0);
3427: }

3429: PETSC_INTERN PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);

3433: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3434: {
3435:   PetscDrawLG      lg;
3436:   PetscErrorCode   ierr;
3437:   PetscReal        x,y,per;
3438:   PetscViewer      v = (PetscViewer)monctx;
3439:   static PetscReal prev; /* should be in the context */
3440:   PetscDraw        draw;

3444:   PetscViewerDrawGetDrawLG(v,0,&lg);
3445:   if (!n) {PetscDrawLGReset(lg);}
3446:   PetscDrawLGGetDraw(lg,&draw);
3447:   PetscDrawSetTitle(draw,"Residual norm");
3448:   x    = (PetscReal)n;
3449:   if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3450:   else y = -15.0;
3451:   PetscDrawLGAddPoint(lg,&x,&y);
3452:   if (n < 20 || !(n % 5) || snes->reason) {
3453:     PetscDrawLGDraw(lg);
3454:     PetscDrawLGSave(lg);
3455:   }

3457:   PetscViewerDrawGetDrawLG(v,1,&lg);
3458:   if (!n) {PetscDrawLGReset(lg);}
3459:   PetscDrawLGGetDraw(lg,&draw);
3460:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3461:    SNESMonitorRange_Private(snes,n,&per);
3462:   x    = (PetscReal)n;
3463:   y    = 100.0*per;
3464:   PetscDrawLGAddPoint(lg,&x,&y);
3465:   if (n < 20 || !(n % 5) || snes->reason) {
3466:     PetscDrawLGDraw(lg);
3467:     PetscDrawLGSave(lg);
3468:   }

3470:   PetscViewerDrawGetDrawLG(v,2,&lg);
3471:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3472:   PetscDrawLGGetDraw(lg,&draw);
3473:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3474:   x    = (PetscReal)n;
3475:   y    = (prev - rnorm)/prev;
3476:   PetscDrawLGAddPoint(lg,&x,&y);
3477:   if (n < 20 || !(n % 5) || snes->reason) {
3478:     PetscDrawLGDraw(lg);
3479:     PetscDrawLGSave(lg);
3480:   }

3482:   PetscViewerDrawGetDrawLG(v,3,&lg);
3483:   if (!n) {PetscDrawLGReset(lg);}
3484:   PetscDrawLGGetDraw(lg,&draw);
3485:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3486:   x    = (PetscReal)n;
3487:   y    = (prev - rnorm)/(prev*per);
3488:   if (n > 2) { /*skip initial crazy value */
3489:     PetscDrawLGAddPoint(lg,&x,&y);
3490:   }
3491:   if (n < 20 || !(n % 5) || snes->reason) {
3492:     PetscDrawLGDraw(lg);
3493:     PetscDrawLGSave(lg);
3494:   }
3495:   prev = rnorm;
3496:   return(0);
3497: }

3501: /*@
3502:    SNESMonitor - runs the user provided monitor routines, if they exist

3504:    Collective on SNES

3506:    Input Parameters:
3507: +  snes - nonlinear solver context obtained from SNESCreate()
3508: .  iter - iteration number
3509: -  rnorm - relative norm of the residual

3511:    Notes:
3512:    This routine is called by the SNES implementations.
3513:    It does not typically need to be called by the user.

3515:    Level: developer

3517: .seealso: SNESMonitorSet()
3518: @*/
3519: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3520: {
3522:   PetscInt       i,n = snes->numbermonitors;

3525:   VecLockPush(snes->vec_sol);
3526:   for (i=0; i<n; i++) {
3527:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3528:   }
3529:   VecLockPop(snes->vec_sol);
3530:   return(0);
3531: }

3533: /* ------------ Routines to set performance monitoring options ----------- */

3535: /*MC
3536:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3538:      Synopsis:
3539:      #include <petscsnes.h>
3540: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3542: +    snes - the SNES context
3543: .    its - iteration number
3544: .    norm - 2-norm function value (may be estimated)
3545: -    mctx - [optional] monitoring context

3547:    Level: advanced

3549: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3550: M*/

3554: /*@C
3555:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3556:    iteration of the nonlinear solver to display the iteration's
3557:    progress.

3559:    Logically Collective on SNES

3561:    Input Parameters:
3562: +  snes - the SNES context
3563: .  f - the monitor function, see SNESMonitorFunction for the calling sequence
3564: .  mctx - [optional] user-defined context for private data for the
3565:           monitor routine (use NULL if no context is desired)
3566: -  monitordestroy - [optional] routine that frees monitor context
3567:           (may be NULL)

3569:    Options Database Keys:
3570: +    -snes_monitor        - sets SNESMonitorDefault()
3571: .    -snes_monitor_lg_residualnorm    - sets line graph monitor,
3572:                             uses SNESMonitorLGCreate()
3573: -    -snes_monitor_cancel - cancels all monitors that have
3574:                             been hardwired into a code by
3575:                             calls to SNESMonitorSet(), but
3576:                             does not cancel those set via
3577:                             the options database.

3579:    Notes:
3580:    Several different monitoring routines may be set by calling
3581:    SNESMonitorSet() multiple times; all will be called in the
3582:    order in which they were set.

3584:    Fortran notes: Only a single monitor function can be set for each SNES object

3586:    Level: intermediate

3588: .keywords: SNES, nonlinear, set, monitor

3590: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3591: @*/
3592: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*f)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3593: {
3594:   PetscInt       i;
3596:   PetscBool      identical;

3600:   for (i=0; i<snes->numbermonitors;i++) {
3601:     PetscMonitorCompare((PetscErrorCode (*)(void))f,mctx,monitordestroy,(PetscErrorCode (*)(void))snes->monitor[i],snes->monitorcontext[i],snes->monitordestroy[i],&identical);
3602:     if (identical) return(0);
3603:   }
3604:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3605:   snes->monitor[snes->numbermonitors]          = f;
3606:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3607:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3608:   return(0);
3609: }

3613: /*@
3614:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3616:    Logically Collective on SNES

3618:    Input Parameters:
3619: .  snes - the SNES context

3621:    Options Database Key:
3622: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
3623:     into a code by calls to SNESMonitorSet(), but does not cancel those
3624:     set via the options database

3626:    Notes:
3627:    There is no way to clear one specific monitor from a SNES object.

3629:    Level: intermediate

3631: .keywords: SNES, nonlinear, set, monitor

3633: .seealso: SNESMonitorDefault(), SNESMonitorSet()
3634: @*/
3635: PetscErrorCode  SNESMonitorCancel(SNES snes)
3636: {
3638:   PetscInt       i;

3642:   for (i=0; i<snes->numbermonitors; i++) {
3643:     if (snes->monitordestroy[i]) {
3644:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
3645:     }
3646:   }
3647:   snes->numbermonitors = 0;
3648:   return(0);
3649: }

3651: /*MC
3652:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

3654:      Synopsis:
3655:      #include <petscsnes.h>
3656: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

3658: +    snes - the SNES context
3659: .    it - current iteration (0 is the first and is before any Newton step)
3660: .    cctx - [optional] convergence context
3661: .    reason - reason for convergence/divergence
3662: .    xnorm - 2-norm of current iterate
3663: .    gnorm - 2-norm of current step
3664: -    f - 2-norm of function

3666:    Level: intermediate

3668: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
3669: M*/

3673: /*@C
3674:    SNESSetConvergenceTest - Sets the function that is to be used
3675:    to test for convergence of the nonlinear iterative solution.

3677:    Logically Collective on SNES

3679:    Input Parameters:
3680: +  snes - the SNES context
3681: .  SNESConvergenceTestFunction - routine to test for convergence
3682: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
3683: -  destroy - [optional] destructor for the context (may be NULL; NULL_FUNCTION in Fortran)

3685:    Level: advanced

3687: .keywords: SNES, nonlinear, set, convergence, test

3689: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
3690: @*/
3691: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
3692: {

3697:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
3698:   if (snes->ops->convergeddestroy) {
3699:     (*snes->ops->convergeddestroy)(snes->cnvP);
3700:   }
3701:   snes->ops->converged        = SNESConvergenceTestFunction;
3702:   snes->ops->convergeddestroy = destroy;
3703:   snes->cnvP                  = cctx;
3704:   return(0);
3705: }

3709: /*@
3710:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

3712:    Not Collective

3714:    Input Parameter:
3715: .  snes - the SNES context

3717:    Output Parameter:
3718: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3719:             manual pages for the individual convergence tests for complete lists

3721:    Options Database:
3722: .   -snes_converged_reason - prints the reason to standard out

3724:    Level: intermediate

3726:    Notes: Should only be called after the call the SNESSolve() is complete, if it is called earlier it returns the value SNES__CONVERGED_ITERATING.

3728: .keywords: SNES, nonlinear, set, convergence, test

3730: .seealso: SNESSetConvergenceTest(), SNESSetConvergedReason(), SNESConvergedReason
3731: @*/
3732: PetscErrorCode SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
3733: {
3737:   *reason = snes->reason;
3738:   return(0);
3739: }

3743: /*@
3744:    SNESSetConvergedReason - Sets the reason the SNES iteration was stopped.

3746:    Not Collective

3748:    Input Parameters:
3749: +  snes - the SNES context
3750: -  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3751:             manual pages for the individual convergence tests for complete lists

3753:    Level: intermediate

3755: .keywords: SNES, nonlinear, set, convergence, test
3756: .seealso: SNESGetConvergedReason(), SNESSetConvergenceTest(), SNESConvergedReason
3757: @*/
3758: PetscErrorCode SNESSetConvergedReason(SNES snes,SNESConvergedReason reason)
3759: {
3762:   snes->reason = reason;
3763:   return(0);
3764: }

3768: /*@
3769:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

3771:    Logically Collective on SNES

3773:    Input Parameters:
3774: +  snes - iterative context obtained from SNESCreate()
3775: .  a   - array to hold history, this array will contain the function norms computed at each step
3776: .  its - integer array holds the number of linear iterations for each solve.
3777: .  na  - size of a and its
3778: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
3779:            else it continues storing new values for new nonlinear solves after the old ones

3781:    Notes:
3782:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
3783:    default array of length 10000 is allocated.

3785:    This routine is useful, e.g., when running a code for purposes
3786:    of accurate performance monitoring, when no I/O should be done
3787:    during the section of code that is being timed.

3789:    Level: intermediate

3791: .keywords: SNES, set, convergence, history

3793: .seealso: SNESGetConvergenceHistory()

3795: @*/
3796: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
3797: {

3804:   if (!a) {
3805:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
3806:     PetscCalloc1(na,&a);
3807:     PetscCalloc1(na,&its);

3809:     snes->conv_malloc = PETSC_TRUE;
3810:   }
3811:   snes->conv_hist       = a;
3812:   snes->conv_hist_its   = its;
3813:   snes->conv_hist_max   = na;
3814:   snes->conv_hist_len   = 0;
3815:   snes->conv_hist_reset = reset;
3816:   return(0);
3817: }

3819: #if defined(PETSC_HAVE_MATLAB_ENGINE)
3820: #include <engine.h>   /* MATLAB include file */
3821: #include <mex.h>      /* MATLAB include file */

3825: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
3826: {
3827:   mxArray   *mat;
3828:   PetscInt  i;
3829:   PetscReal *ar;

3832:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
3833:   ar  = (PetscReal*) mxGetData(mat);
3834:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
3835:   PetscFunctionReturn(mat);
3836: }
3837: #endif

3841: /*@C
3842:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

3844:    Not Collective

3846:    Input Parameter:
3847: .  snes - iterative context obtained from SNESCreate()

3849:    Output Parameters:
3850: .  a   - array to hold history
3851: .  its - integer array holds the number of linear iterations (or
3852:          negative if not converged) for each solve.
3853: -  na  - size of a and its

3855:    Notes:
3856:     The calling sequence for this routine in Fortran is
3857: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

3859:    This routine is useful, e.g., when running a code for purposes
3860:    of accurate performance monitoring, when no I/O should be done
3861:    during the section of code that is being timed.

3863:    Level: intermediate

3865: .keywords: SNES, get, convergence, history

3867: .seealso: SNESSetConvergencHistory()

3869: @*/
3870: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
3871: {
3874:   if (a)   *a   = snes->conv_hist;
3875:   if (its) *its = snes->conv_hist_its;
3876:   if (na)  *na  = snes->conv_hist_len;
3877:   return(0);
3878: }

3882: /*@C
3883:   SNESSetUpdate - Sets the general-purpose update function called
3884:   at the beginning of every iteration of the nonlinear solve. Specifically
3885:   it is called just before the Jacobian is "evaluated".

3887:   Logically Collective on SNES

3889:   Input Parameters:
3890: . snes - The nonlinear solver context
3891: . func - The function

3893:   Calling sequence of func:
3894: . func (SNES snes, PetscInt step);

3896: . step - The current step of the iteration

3898:   Level: advanced

3900:   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()
3901:         This is not used by most users.

3903: .keywords: SNES, update

3905: .seealso SNESSetJacobian(), SNESSolve()
3906: @*/
3907: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
3908: {
3911:   snes->ops->update = func;
3912:   return(0);
3913: }

3917: /*
3918:    SNESScaleStep_Private - Scales a step so that its length is less than the
3919:    positive parameter delta.

3921:     Input Parameters:
3922: +   snes - the SNES context
3923: .   y - approximate solution of linear system
3924: .   fnorm - 2-norm of current function
3925: -   delta - trust region size

3927:     Output Parameters:
3928: +   gpnorm - predicted function norm at the new point, assuming local
3929:     linearization.  The value is zero if the step lies within the trust
3930:     region, and exceeds zero otherwise.
3931: -   ynorm - 2-norm of the step

3933:     Note:
3934:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
3935:     is set to be the maximum allowable step size.

3937: .keywords: SNES, nonlinear, scale, step
3938: */
3939: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
3940: {
3941:   PetscReal      nrm;
3942:   PetscScalar    cnorm;


3950:   VecNorm(y,NORM_2,&nrm);
3951:   if (nrm > *delta) {
3952:     nrm     = *delta/nrm;
3953:     *gpnorm = (1.0 - nrm)*(*fnorm);
3954:     cnorm   = nrm;
3955:     VecScale(y,cnorm);
3956:     *ynorm  = *delta;
3957:   } else {
3958:     *gpnorm = 0.0;
3959:     *ynorm  = nrm;
3960:   }
3961:   return(0);
3962: }

3966: /*@
3967:    SNESReasonView - Displays the reason a SNES solve converged or diverged to a viewer

3969:    Collective on SNES

3971:    Parameter:
3972: +  snes - iterative context obtained from SNESCreate()
3973: -  viewer - the viewer to display the reason


3976:    Options Database Keys:
3977: .  -snes_converged_reason - print reason for converged or diverged, also prints number of iterations

3979:    Level: beginner

3981: .keywords: SNES, solve, linear system

3983: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault()

3985: @*/
3986: PetscErrorCode  SNESReasonView(SNES snes,PetscViewer viewer)
3987: {
3989:   PetscBool      isAscii;

3992:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isAscii);
3993:   if (isAscii) {
3994:     PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);
3995:     if (snes->reason > 0) {
3996:       if (((PetscObject) snes)->prefix) {
3997:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve converged due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
3998:       } else {
3999:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4000:       }
4001:     } else {
4002:       if (((PetscObject) snes)->prefix) {
4003:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve did not converge due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4004:       } else {
4005:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4006:       }
4007:     }
4008:     PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);
4009:   }
4010:   return(0);
4011: }

4015: /*@C
4016:   SNESReasonViewFromOptions - Processes command line options to determine if/how a SNESReason is to be viewed. 

4018:   Collective on SNES

4020:   Input Parameters:
4021: . snes   - the SNES object

4023:   Level: intermediate

4025: @*/
4026: PetscErrorCode SNESReasonViewFromOptions(SNES snes)
4027: {
4028:   PetscErrorCode    ierr;
4029:   PetscViewer       viewer;
4030:   PetscBool         flg;
4031:   static PetscBool  incall = PETSC_FALSE;
4032:   PetscViewerFormat format;

4035:   if (incall) return(0);
4036:   incall = PETSC_TRUE;
4037:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_converged_reason",&viewer,&format,&flg);
4038:   if (flg) {
4039:     PetscViewerPushFormat(viewer,format);
4040:     SNESReasonView(snes,viewer);
4041:     PetscViewerPopFormat(viewer);
4042:     PetscViewerDestroy(&viewer);
4043:   }
4044:   incall = PETSC_FALSE;
4045:   return(0);
4046: }

4050: /*@C
4051:    SNESSolve - Solves a nonlinear system F(x) = b.
4052:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

4054:    Collective on SNES

4056:    Input Parameters:
4057: +  snes - the SNES context
4058: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
4059: -  x - the solution vector.

4061:    Notes:
4062:    The user should initialize the vector,x, with the initial guess
4063:    for the nonlinear solve prior to calling SNESSolve.  In particular,
4064:    to employ an initial guess of zero, the user should explicitly set
4065:    this vector to zero by calling VecSet().

4067:    Level: beginner

4069: .keywords: SNES, nonlinear, solve

4071: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
4072: @*/
4073: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
4074: {
4075:   PetscErrorCode    ierr;
4076:   PetscBool         flg;
4077:   PetscInt          grid;
4078:   Vec               xcreated = NULL;
4079:   DM                dm;


4088:   if (!x) {
4089:     SNESGetDM(snes,&dm);
4090:     DMCreateGlobalVector(dm,&xcreated);
4091:     x    = xcreated;
4092:   }
4093:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

4095:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
4096:   for (grid=0; grid<snes->gridsequence+1; grid++) {

4098:     /* set solution vector */
4099:     if (!grid) {PetscObjectReference((PetscObject)x);}
4100:     VecDestroy(&snes->vec_sol);
4101:     snes->vec_sol = x;
4102:     SNESGetDM(snes,&dm);

4104:     /* set affine vector if provided */
4105:     if (b) { PetscObjectReference((PetscObject)b); }
4106:     VecDestroy(&snes->vec_rhs);
4107:     snes->vec_rhs = b;

4109:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
4110:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
4111:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
4112:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
4113:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
4114:     }
4115:     DMShellSetGlobalVector(dm,snes->vec_sol);
4116:     SNESSetUp(snes);

4118:     if (!grid) {
4119:       if (snes->ops->computeinitialguess) {
4120:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
4121:       }
4122:     }

4124:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4125:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

4127:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
4128:     (*snes->ops->solve)(snes);
4129:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
4130:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");
4131:     snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */

4133:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4134:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

4136:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_test_local_min",NULL,NULL,&flg);
4137:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
4138:     SNESReasonViewFromOptions(snes);

4140:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
4141:     if (snes->reason < 0) break;
4142:     if (grid <  snes->gridsequence) {
4143:       DM  fine;
4144:       Vec xnew;
4145:       Mat interp;

4147:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
4148:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
4149:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
4150:       DMCreateGlobalVector(fine,&xnew);
4151:       MatInterpolate(interp,x,xnew);
4152:       DMInterpolate(snes->dm,interp,fine);
4153:       MatDestroy(&interp);
4154:       x    = xnew;

4156:       SNESReset(snes);
4157:       SNESSetDM(snes,fine);
4158:       DMDestroy(&fine);
4159:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
4160:     }
4161:   }
4162:   SNESViewFromOptions(snes,NULL,"-snes_view");
4163:   VecViewFromOptions(snes->vec_sol,(PetscObject)snes,"-snes_view_solution");

4165:   VecDestroy(&xcreated);
4166:   PetscObjectSAWsBlock((PetscObject)snes);
4167:   return(0);
4168: }

4170: /* --------- Internal routines for SNES Package --------- */

4174: /*@C
4175:    SNESSetType - Sets the method for the nonlinear solver.

4177:    Collective on SNES

4179:    Input Parameters:
4180: +  snes - the SNES context
4181: -  type - a known method

4183:    Options Database Key:
4184: .  -snes_type <type> - Sets the method; use -help for a list
4185:    of available methods (for instance, newtonls or newtontr)

4187:    Notes:
4188:    See "petsc/include/petscsnes.h" for available methods (for instance)
4189: +    SNESNEWTONLS - Newton's method with line search
4190:      (systems of nonlinear equations)
4191: .    SNESNEWTONTR - Newton's method with trust region
4192:      (systems of nonlinear equations)

4194:   Normally, it is best to use the SNESSetFromOptions() command and then
4195:   set the SNES solver type from the options database rather than by using
4196:   this routine.  Using the options database provides the user with
4197:   maximum flexibility in evaluating the many nonlinear solvers.
4198:   The SNESSetType() routine is provided for those situations where it
4199:   is necessary to set the nonlinear solver independently of the command
4200:   line or options database.  This might be the case, for example, when
4201:   the choice of solver changes during the execution of the program,
4202:   and the user's application is taking responsibility for choosing the
4203:   appropriate method.

4205:     Developer Notes: SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
4206:     the constructor in that list and calls it to create the spexific object.

4208:   Level: intermediate

4210: .keywords: SNES, set, type

4212: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

4214: @*/
4215: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
4216: {
4217:   PetscErrorCode ierr,(*r)(SNES);
4218:   PetscBool      match;


4224:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
4225:   if (match) return(0);

4227:    PetscFunctionListFind(SNESList,type,&r);
4228:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
4229:   /* Destroy the previous private SNES context */
4230:   if (snes->ops->destroy) {
4231:     (*(snes)->ops->destroy)(snes);
4232:     snes->ops->destroy = NULL;
4233:   }
4234:   /* Reinitialize function pointers in SNESOps structure */
4235:   snes->ops->setup          = 0;
4236:   snes->ops->solve          = 0;
4237:   snes->ops->view           = 0;
4238:   snes->ops->setfromoptions = 0;
4239:   snes->ops->destroy        = 0;
4240:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4241:   snes->setupcalled = PETSC_FALSE;

4243:   PetscObjectChangeTypeName((PetscObject)snes,type);
4244:   (*r)(snes);
4245:   return(0);
4246: }

4250: /*@C
4251:    SNESGetType - Gets the SNES method type and name (as a string).

4253:    Not Collective

4255:    Input Parameter:
4256: .  snes - nonlinear solver context

4258:    Output Parameter:
4259: .  type - SNES method (a character string)

4261:    Level: intermediate

4263: .keywords: SNES, nonlinear, get, type, name
4264: @*/
4265: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
4266: {
4270:   *type = ((PetscObject)snes)->type_name;
4271:   return(0);
4272: }

4276: /*@
4277:   SNESSetSolution - Sets the solution vector for use by the SNES routines.

4279:   Logically Collective on SNES and Vec

4281:   Input Parameters:
4282: + snes - the SNES context obtained from SNESCreate()
4283: - u    - the solution vector

4285:   Level: beginner

4287: .keywords: SNES, set, solution
4288: @*/
4289: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4290: {
4291:   DM             dm;

4297:   PetscObjectReference((PetscObject) u);
4298:   VecDestroy(&snes->vec_sol);

4300:   snes->vec_sol = u;

4302:   SNESGetDM(snes, &dm);
4303:   DMShellSetGlobalVector(dm, u);
4304:   return(0);
4305: }

4309: /*@
4310:    SNESGetSolution - Returns the vector where the approximate solution is
4311:    stored. This is the fine grid solution when using SNESSetGridSequence().

4313:    Not Collective, but Vec is parallel if SNES is parallel

4315:    Input Parameter:
4316: .  snes - the SNES context

4318:    Output Parameter:
4319: .  x - the solution

4321:    Level: intermediate

4323: .keywords: SNES, nonlinear, get, solution

4325: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
4326: @*/
4327: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
4328: {
4332:   *x = snes->vec_sol;
4333:   return(0);
4334: }

4338: /*@
4339:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4340:    stored.

4342:    Not Collective, but Vec is parallel if SNES is parallel

4344:    Input Parameter:
4345: .  snes - the SNES context

4347:    Output Parameter:
4348: .  x - the solution update

4350:    Level: advanced

4352: .keywords: SNES, nonlinear, get, solution, update

4354: .seealso: SNESGetSolution(), SNESGetFunction()
4355: @*/
4356: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4357: {
4361:   *x = snes->vec_sol_update;
4362:   return(0);
4363: }

4367: /*@C
4368:    SNESGetFunction - Returns the vector where the function is stored.

4370:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4372:    Input Parameter:
4373: .  snes - the SNES context

4375:    Output Parameter:
4376: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4377: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4378: -  ctx - the function context (or NULL if you don't want it)

4380:    Level: advanced

4382: .keywords: SNES, nonlinear, get, function

4384: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4385: @*/
4386: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4387: {
4389:   DM             dm;

4393:   if (r) {
4394:     if (!snes->vec_func) {
4395:       if (snes->vec_rhs) {
4396:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4397:       } else if (snes->vec_sol) {
4398:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4399:       } else if (snes->dm) {
4400:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4401:       }
4402:     }
4403:     *r = snes->vec_func;
4404:   }
4405:   SNESGetDM(snes,&dm);
4406:   DMSNESGetFunction(dm,f,ctx);
4407:   return(0);
4408: }

4410: /*@C
4411:    SNESGetNGS - Returns the NGS function and context.

4413:    Input Parameter:
4414: .  snes - the SNES context

4416:    Output Parameter:
4417: +  f - the function (or NULL) see SNESNGSFunction for details
4418: -  ctx    - the function context (or NULL)

4420:    Level: advanced

4422: .keywords: SNES, nonlinear, get, function

4424: .seealso: SNESSetNGS(), SNESGetFunction()
4425: @*/

4429: PetscErrorCode SNESGetNGS (SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void*), void ** ctx)
4430: {
4432:   DM             dm;

4436:   SNESGetDM(snes,&dm);
4437:   DMSNESGetNGS(dm,f,ctx);
4438:   return(0);
4439: }

4443: /*@C
4444:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4445:    SNES options in the database.

4447:    Logically Collective on SNES

4449:    Input Parameter:
4450: +  snes - the SNES context
4451: -  prefix - the prefix to prepend to all option names

4453:    Notes:
4454:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4455:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4457:    Level: advanced

4459: .keywords: SNES, set, options, prefix, database

4461: .seealso: SNESSetFromOptions()
4462: @*/
4463: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4464: {

4469:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4470:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4471:   if (snes->linesearch) {
4472:     SNESGetLineSearch(snes,&snes->linesearch);
4473:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4474:   }
4475:   KSPSetOptionsPrefix(snes->ksp,prefix);
4476:   return(0);
4477: }

4481: /*@C
4482:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4483:    SNES options in the database.

4485:    Logically Collective on SNES

4487:    Input Parameters:
4488: +  snes - the SNES context
4489: -  prefix - the prefix to prepend to all option names

4491:    Notes:
4492:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4493:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4495:    Level: advanced

4497: .keywords: SNES, append, options, prefix, database

4499: .seealso: SNESGetOptionsPrefix()
4500: @*/
4501: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
4502: {

4507:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
4508:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4509:   if (snes->linesearch) {
4510:     SNESGetLineSearch(snes,&snes->linesearch);
4511:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
4512:   }
4513:   KSPAppendOptionsPrefix(snes->ksp,prefix);
4514:   return(0);
4515: }

4519: /*@C
4520:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
4521:    SNES options in the database.

4523:    Not Collective

4525:    Input Parameter:
4526: .  snes - the SNES context

4528:    Output Parameter:
4529: .  prefix - pointer to the prefix string used

4531:    Notes: On the fortran side, the user should pass in a string 'prefix' of
4532:    sufficient length to hold the prefix.

4534:    Level: advanced

4536: .keywords: SNES, get, options, prefix, database

4538: .seealso: SNESAppendOptionsPrefix()
4539: @*/
4540: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
4541: {

4546:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
4547:   return(0);
4548: }


4553: /*@C
4554:   SNESRegister - Adds a method to the nonlinear solver package.

4556:    Not collective

4558:    Input Parameters:
4559: +  name_solver - name of a new user-defined solver
4560: -  routine_create - routine to create method context

4562:    Notes:
4563:    SNESRegister() may be called multiple times to add several user-defined solvers.

4565:    Sample usage:
4566: .vb
4567:    SNESRegister("my_solver",MySolverCreate);
4568: .ve

4570:    Then, your solver can be chosen with the procedural interface via
4571: $     SNESSetType(snes,"my_solver")
4572:    or at runtime via the option
4573: $     -snes_type my_solver

4575:    Level: advanced

4577:     Note: If your function is not being put into a shared library then use SNESRegister() instead

4579: .keywords: SNES, nonlinear, register

4581: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

4583:   Level: advanced
4584: @*/
4585: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
4586: {

4590:   PetscFunctionListAdd(&SNESList,sname,function);
4591:   return(0);
4592: }

4596: PetscErrorCode  SNESTestLocalMin(SNES snes)
4597: {
4599:   PetscInt       N,i,j;
4600:   Vec            u,uh,fh;
4601:   PetscScalar    value;
4602:   PetscReal      norm;

4605:   SNESGetSolution(snes,&u);
4606:   VecDuplicate(u,&uh);
4607:   VecDuplicate(u,&fh);

4609:   /* currently only works for sequential */
4610:   PetscPrintf(PETSC_COMM_WORLD,"Testing FormFunction() for local min\n");
4611:   VecGetSize(u,&N);
4612:   for (i=0; i<N; i++) {
4613:     VecCopy(u,uh);
4614:     PetscPrintf(PETSC_COMM_WORLD,"i = %D\n",i);
4615:     for (j=-10; j<11; j++) {
4616:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
4617:       VecSetValue(uh,i,value,ADD_VALUES);
4618:       SNESComputeFunction(snes,uh,fh);
4619:       VecNorm(fh,NORM_2,&norm);
4620:       PetscPrintf(PETSC_COMM_WORLD,"       j norm %D %18.16e\n",j,norm);
4621:       value = -value;
4622:       VecSetValue(uh,i,value,ADD_VALUES);
4623:     }
4624:   }
4625:   VecDestroy(&uh);
4626:   VecDestroy(&fh);
4627:   return(0);
4628: }

4632: /*@
4633:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
4634:    computing relative tolerance for linear solvers within an inexact
4635:    Newton method.

4637:    Logically Collective on SNES

4639:    Input Parameters:
4640: +  snes - SNES context
4641: -  flag - PETSC_TRUE or PETSC_FALSE

4643:     Options Database:
4644: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
4645: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
4646: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
4647: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
4648: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
4649: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
4650: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
4651: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

4653:    Notes:
4654:    Currently, the default is to use a constant relative tolerance for
4655:    the inner linear solvers.  Alternatively, one can use the
4656:    Eisenstat-Walker method, where the relative convergence tolerance
4657:    is reset at each Newton iteration according progress of the nonlinear
4658:    solver.

4660:    Level: advanced

4662:    Reference:
4663:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4664:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4666: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4668: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4669: @*/
4670: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
4671: {
4675:   snes->ksp_ewconv = flag;
4676:   return(0);
4677: }

4681: /*@
4682:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
4683:    for computing relative tolerance for linear solvers within an
4684:    inexact Newton method.

4686:    Not Collective

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

4691:    Output Parameter:
4692: .  flag - PETSC_TRUE or PETSC_FALSE

4694:    Notes:
4695:    Currently, the default is to use a constant relative tolerance for
4696:    the inner linear solvers.  Alternatively, one can use the
4697:    Eisenstat-Walker method, where the relative convergence tolerance
4698:    is reset at each Newton iteration according progress of the nonlinear
4699:    solver.

4701:    Level: advanced

4703:    Reference:
4704:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4705:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4707: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4709: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4710: @*/
4711: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
4712: {
4716:   *flag = snes->ksp_ewconv;
4717:   return(0);
4718: }

4722: /*@
4723:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
4724:    convergence criteria for the linear solvers within an inexact
4725:    Newton method.

4727:    Logically Collective on SNES

4729:    Input Parameters:
4730: +    snes - SNES context
4731: .    version - version 1, 2 (default is 2) or 3
4732: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4733: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4734: .    gamma - multiplicative factor for version 2 rtol computation
4735:              (0 <= gamma2 <= 1)
4736: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4737: .    alpha2 - power for safeguard
4738: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4740:    Note:
4741:    Version 3 was contributed by Luis Chacon, June 2006.

4743:    Use PETSC_DEFAULT to retain the default for any of the parameters.

4745:    Level: advanced

4747:    Reference:
4748:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4749:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
4750:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

4752: .keywords: SNES, KSP, Eisenstat, Walker, set, parameters

4754: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
4755: @*/
4756: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
4757: {
4758:   SNESKSPEW *kctx;

4762:   kctx = (SNESKSPEW*)snes->kspconvctx;
4763:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

4772:   if (version != PETSC_DEFAULT)   kctx->version   = version;
4773:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
4774:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
4775:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
4776:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
4777:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
4778:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

4780:   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);
4781:   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);
4782:   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);
4783:   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);
4784:   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);
4785:   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);
4786:   return(0);
4787: }

4791: /*@
4792:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
4793:    convergence criteria for the linear solvers within an inexact
4794:    Newton method.

4796:    Not Collective

4798:    Input Parameters:
4799:      snes - SNES context

4801:    Output Parameters:
4802: +    version - version 1, 2 (default is 2) or 3
4803: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4804: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4805: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
4806: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4807: .    alpha2 - power for safeguard
4808: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4810:    Level: advanced

4812: .keywords: SNES, KSP, Eisenstat, Walker, get, parameters

4814: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
4815: @*/
4816: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
4817: {
4818:   SNESKSPEW *kctx;

4822:   kctx = (SNESKSPEW*)snes->kspconvctx;
4823:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
4824:   if (version)   *version   = kctx->version;
4825:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
4826:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
4827:   if (gamma)     *gamma     = kctx->gamma;
4828:   if (alpha)     *alpha     = kctx->alpha;
4829:   if (alpha2)    *alpha2    = kctx->alpha2;
4830:   if (threshold) *threshold = kctx->threshold;
4831:   return(0);
4832: }

4836:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
4837: {
4839:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
4840:   PetscReal      rtol  = PETSC_DEFAULT,stol;

4843:   if (!snes->ksp_ewconv) return(0);
4844:   if (!snes->iter) {
4845:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
4846:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
4847:   }
4848:   else {
4849:     if (kctx->version == 1) {
4850:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
4851:       if (rtol < 0.0) rtol = -rtol;
4852:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
4853:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
4854:     } else if (kctx->version == 2) {
4855:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
4856:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
4857:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
4858:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
4859:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
4860:       /* safeguard: avoid sharp decrease of rtol */
4861:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
4862:       stol = PetscMax(rtol,stol);
4863:       rtol = PetscMin(kctx->rtol_0,stol);
4864:       /* safeguard: avoid oversolving */
4865:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
4866:       stol = PetscMax(rtol,stol);
4867:       rtol = PetscMin(kctx->rtol_0,stol);
4868:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
4869:   }
4870:   /* safeguard: avoid rtol greater than one */
4871:   rtol = PetscMin(rtol,kctx->rtol_max);
4872:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
4873:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
4874:   return(0);
4875: }

4879: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
4880: {
4882:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
4883:   PCSide         pcside;
4884:   Vec            lres;

4887:   if (!snes->ksp_ewconv) return(0);
4888:   KSPGetTolerances(ksp,&kctx->rtol_last,0,0,0);
4889:   kctx->norm_last = snes->norm;
4890:   if (kctx->version == 1) {
4891:     PC        pc;
4892:     PetscBool isNone;

4894:     KSPGetPC(ksp, &pc);
4895:     PetscObjectTypeCompare((PetscObject) pc, PCNONE, &isNone);
4896:     KSPGetPCSide(ksp,&pcside);
4897:      if (pcside == PC_RIGHT || isNone) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
4898:       /* KSP residual is true linear residual */
4899:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
4900:     } else {
4901:       /* KSP residual is preconditioned residual */
4902:       /* compute true linear residual norm */
4903:       VecDuplicate(b,&lres);
4904:       MatMult(snes->jacobian,x,lres);
4905:       VecAYPX(lres,-1.0,b);
4906:       VecNorm(lres,NORM_2,&kctx->lresid_last);
4907:       VecDestroy(&lres);
4908:     }
4909:   }
4910:   return(0);
4911: }

4915: /*@
4916:    SNESGetKSP - Returns the KSP context for a SNES solver.

4918:    Not Collective, but if SNES object is parallel, then KSP object is parallel

4920:    Input Parameter:
4921: .  snes - the SNES context

4923:    Output Parameter:
4924: .  ksp - the KSP context

4926:    Notes:
4927:    The user can then directly manipulate the KSP context to set various
4928:    options, etc.  Likewise, the user can then extract and manipulate the
4929:    PC contexts as well.

4931:    Level: beginner

4933: .keywords: SNES, nonlinear, get, KSP, context

4935: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
4936: @*/
4937: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
4938: {


4945:   if (!snes->ksp) {
4946:     PetscBool monitor = PETSC_FALSE;

4948:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
4949:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
4950:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

4952:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
4953:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);

4955:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes",&monitor,NULL);
4956:     if (monitor) {
4957:       KSPMonitorSet(snes->ksp,KSPMonitorSNES,snes,NULL);
4958:     }
4959:     monitor = PETSC_FALSE;
4960:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes_lg",&monitor,NULL);
4961:     if (monitor) {
4962:       PetscObject *objs;
4963:       KSPMonitorSNESLGResidualNormCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,600,600,&objs);
4964:       objs[0] = (PetscObject) snes;
4965:       KSPMonitorSet(snes->ksp,(PetscErrorCode (*)(KSP,PetscInt,PetscReal,void*))KSPMonitorSNESLGResidualNorm,objs,(PetscErrorCode (*)(void**))KSPMonitorSNESLGResidualNormDestroy);
4966:     }
4967:   }
4968:   *ksp = snes->ksp;
4969:   return(0);
4970: }


4973:  #include <petsc/private/dmimpl.h>
4976: /*@
4977:    SNESSetDM - Sets the DM that may be used by some nonlinear solvers or their underlying preconditioners

4979:    Logically Collective on SNES

4981:    Input Parameters:
4982: +  snes - the nonlinear solver context
4983: -  dm - the dm, cannot be NULL

4985:    Level: intermediate

4987: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
4988: @*/
4989: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
4990: {
4992:   KSP            ksp;
4993:   DMSNES         sdm;

4998:   PetscObjectReference((PetscObject)dm);
4999:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
5000:     if (snes->dm->dmsnes && !dm->dmsnes) {
5001:       DMCopyDMSNES(snes->dm,dm);
5002:       DMGetDMSNES(snes->dm,&sdm);
5003:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5004:     }
5005:     DMDestroy(&snes->dm);
5006:   }
5007:   snes->dm     = dm;
5008:   snes->dmAuto = PETSC_FALSE;

5010:   SNESGetKSP(snes,&ksp);
5011:   KSPSetDM(ksp,dm);
5012:   KSPSetDMActive(ksp,PETSC_FALSE);
5013:   if (snes->pc) {
5014:     SNESSetDM(snes->pc, snes->dm);
5015:     SNESSetNPCSide(snes,snes->pcside);
5016:   }
5017:   return(0);
5018: }

5022: /*@
5023:    SNESGetDM - Gets the DM that may be used by some preconditioners

5025:    Not Collective but DM obtained is parallel on SNES

5027:    Input Parameter:
5028: . snes - the preconditioner context

5030:    Output Parameter:
5031: .  dm - the dm

5033:    Level: intermediate

5035: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
5036: @*/
5037: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
5038: {

5043:   if (!snes->dm) {
5044:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
5045:     snes->dmAuto = PETSC_TRUE;
5046:   }
5047:   *dm = snes->dm;
5048:   return(0);
5049: }

5053: /*@
5054:   SNESSetNPC - Sets the nonlinear preconditioner to be used.

5056:   Collective on SNES

5058:   Input Parameters:
5059: + snes - iterative context obtained from SNESCreate()
5060: - pc   - the preconditioner object

5062:   Notes:
5063:   Use SNESGetNPC() to retrieve the preconditioner context (for example,
5064:   to configure it using the API).

5066:   Level: developer

5068: .keywords: SNES, set, precondition
5069: .seealso: SNESGetNPC(), SNESHasNPC()
5070: @*/
5071: PetscErrorCode SNESSetNPC(SNES snes, SNES pc)
5072: {

5079:   PetscObjectReference((PetscObject) pc);
5080:   SNESDestroy(&snes->pc);
5081:   snes->pc = pc;
5082:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->pc);
5083:   return(0);
5084: }

5088: /*@
5089:   SNESGetNPC - Creates a nonlinear preconditioning solver (SNES) to be used to precondition the nonlinear solver.

5091:   Not Collective

5093:   Input Parameter:
5094: . snes - iterative context obtained from SNESCreate()

5096:   Output Parameter:
5097: . pc - preconditioner context

5099:   Notes: If a SNES was previously set with SNESSetNPC() then that SNES is returned.

5101:   Level: developer

5103: .keywords: SNES, get, preconditioner
5104: .seealso: SNESSetNPC(), SNESHasNPC()
5105: @*/
5106: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5107: {
5109:   const char     *optionsprefix;

5114:   if (!snes->pc) {
5115:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->pc);
5116:     PetscObjectIncrementTabLevel((PetscObject)snes->pc,(PetscObject)snes,1);
5117:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->pc);
5118:     SNESGetOptionsPrefix(snes,&optionsprefix);
5119:     SNESSetOptionsPrefix(snes->pc,optionsprefix);
5120:     SNESAppendOptionsPrefix(snes->pc,"npc_");
5121:     SNESSetCountersReset(snes->pc,PETSC_FALSE);
5122:   }
5123:   *pc = snes->pc;
5124:   return(0);
5125: }

5129: /*@
5130:   SNESHasNPC - Returns whether a nonlinear preconditioner exists

5132:   Not Collective

5134:   Input Parameter:
5135: . snes - iterative context obtained from SNESCreate()

5137:   Output Parameter:
5138: . has_npc - whether the SNES has an NPC or not

5140:   Level: developer

5142: .keywords: SNES, has, preconditioner
5143: .seealso: SNESSetNPC(), SNESGetNPC()
5144: @*/
5145: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5146: {
5149:   *has_npc = (PetscBool) (snes->pc ? PETSC_TRUE : PETSC_FALSE);
5150:   return(0);
5151: }

5155: /*@
5156:     SNESSetNPCSide - Sets the preconditioning side.

5158:     Logically Collective on SNES

5160:     Input Parameter:
5161: .   snes - iterative context obtained from SNESCreate()

5163:     Output Parameter:
5164: .   side - the preconditioning side, where side is one of
5165: .vb
5166:       PC_LEFT - left preconditioning
5167:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5168: .ve

5170:     Options Database Keys:
5171: .   -snes_pc_side <right,left>

5173:     Notes: SNESNRICHARDSON and SNESNCG only support left preconditioning.

5175:     Level: intermediate

5177: .keywords: SNES, set, right, left, side, preconditioner, flag

5179: .seealso: SNESGetNPCSide(), KSPSetPCSide()
5180: @*/
5181: PetscErrorCode  SNESSetNPCSide(SNES snes,PCSide side)
5182: {
5186:   snes->pcside = side;
5187:   return(0);
5188: }

5192: /*@
5193:     SNESGetNPCSide - Gets the preconditioning side.

5195:     Not Collective

5197:     Input Parameter:
5198: .   snes - iterative context obtained from SNESCreate()

5200:     Output Parameter:
5201: .   side - the preconditioning side, where side is one of
5202: .vb
5203:       PC_LEFT - left preconditioning
5204:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5205: .ve

5207:     Level: intermediate

5209: .keywords: SNES, get, right, left, side, preconditioner, flag

5211: .seealso: SNESSetNPCSide(), KSPGetPCSide()
5212: @*/
5213: PetscErrorCode  SNESGetNPCSide(SNES snes,PCSide *side)
5214: {
5218:   *side = snes->pcside;
5219:   return(0);
5220: }

5224: /*@
5225:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

5227:   Collective on SNES

5229:   Input Parameters:
5230: + snes - iterative context obtained from SNESCreate()
5231: - linesearch   - the linesearch object

5233:   Notes:
5234:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
5235:   to configure it using the API).

5237:   Level: developer

5239: .keywords: SNES, set, linesearch
5240: .seealso: SNESGetLineSearch()
5241: @*/
5242: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5243: {

5250:   PetscObjectReference((PetscObject) linesearch);
5251:   SNESLineSearchDestroy(&snes->linesearch);

5253:   snes->linesearch = linesearch;

5255:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5256:   return(0);
5257: }

5261: /*@
5262:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
5263:   or creates a default line search instance associated with the SNES and returns it.

5265:   Not Collective

5267:   Input Parameter:
5268: . snes - iterative context obtained from SNESCreate()

5270:   Output Parameter:
5271: . linesearch - linesearch context

5273:   Level: beginner

5275: .keywords: SNES, get, linesearch
5276: .seealso: SNESSetLineSearch(), SNESLineSearchCreate()
5277: @*/
5278: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5279: {
5281:   const char     *optionsprefix;

5286:   if (!snes->linesearch) {
5287:     SNESGetOptionsPrefix(snes, &optionsprefix);
5288:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
5289:     SNESLineSearchSetSNES(snes->linesearch, snes);
5290:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
5291:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
5292:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5293:   }
5294:   *linesearch = snes->linesearch;
5295:   return(0);
5296: }

5298: #if defined(PETSC_HAVE_MATLAB_ENGINE)
5299: #include <mex.h>

5301: typedef struct {char *funcname; mxArray *ctx;} SNESMatlabContext;

5305: /*
5306:    SNESComputeFunction_Matlab - Calls the function that has been set with SNESSetFunctionMatlab().

5308:    Collective on SNES

5310:    Input Parameters:
5311: +  snes - the SNES context
5312: -  x - input vector

5314:    Output Parameter:
5315: .  y - function vector, as set by SNESSetFunction()

5317:    Notes:
5318:    SNESComputeFunction() is typically used within nonlinear solvers
5319:    implementations, so most users would not generally call this routine
5320:    themselves.

5322:    Level: developer

5324: .keywords: SNES, nonlinear, compute, function

5326: .seealso: SNESSetFunction(), SNESGetFunction()
5327: */
5328: PetscErrorCode  SNESComputeFunction_Matlab(SNES snes,Vec x,Vec y, void *ctx)
5329: {
5330:   PetscErrorCode    ierr;
5331:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5332:   int               nlhs  = 1,nrhs = 5;
5333:   mxArray           *plhs[1],*prhs[5];
5334:   long long int     lx = 0,ly = 0,ls = 0;


5343:   /* call Matlab function in ctx with arguments x and y */

5345:   PetscMemcpy(&ls,&snes,sizeof(snes));
5346:   PetscMemcpy(&lx,&x,sizeof(x));
5347:   PetscMemcpy(&ly,&y,sizeof(x));
5348:   prhs[0] = mxCreateDoubleScalar((double)ls);
5349:   prhs[1] = mxCreateDoubleScalar((double)lx);
5350:   prhs[2] = mxCreateDoubleScalar((double)ly);
5351:   prhs[3] = mxCreateString(sctx->funcname);
5352:   prhs[4] = sctx->ctx;
5353:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeFunctionInternal");
5354:   mxGetScalar(plhs[0]);
5355:   mxDestroyArray(prhs[0]);
5356:   mxDestroyArray(prhs[1]);
5357:   mxDestroyArray(prhs[2]);
5358:   mxDestroyArray(prhs[3]);
5359:   mxDestroyArray(plhs[0]);
5360:   return(0);
5361: }

5365: /*
5366:    SNESSetFunctionMatlab - Sets the function evaluation routine and function
5367:    vector for use by the SNES routines in solving systems of nonlinear
5368:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

5370:    Logically Collective on SNES

5372:    Input Parameters:
5373: +  snes - the SNES context
5374: .  r - vector to store function value
5375: -  f - function evaluation routine

5377:    Notes:
5378:    The Newton-like methods typically solve linear systems of the form
5379: $      f'(x) x = -f(x),
5380:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

5382:    Level: beginner

5384:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5386: .keywords: SNES, nonlinear, set, function

5388: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5389: */
5390: PetscErrorCode  SNESSetFunctionMatlab(SNES snes,Vec r,const char *f,mxArray *ctx)
5391: {
5392:   PetscErrorCode    ierr;
5393:   SNESMatlabContext *sctx;

5396:   /* currently sctx is memory bleed */
5397:   PetscNew(&sctx);
5398:   PetscStrallocpy(f,&sctx->funcname);
5399:   /*
5400:      This should work, but it doesn't
5401:   sctx->ctx = ctx;
5402:   mexMakeArrayPersistent(sctx->ctx);
5403:   */
5404:   sctx->ctx = mxDuplicateArray(ctx);
5405:   SNESSetFunction(snes,r,SNESComputeFunction_Matlab,sctx);
5406:   return(0);
5407: }

5411: /*
5412:    SNESComputeJacobian_Matlab - Calls the function that has been set with SNESSetJacobianMatlab().

5414:    Collective on SNES

5416:    Input Parameters:
5417: +  snes - the SNES context
5418: .  x - input vector
5419: .  A, B - the matrices
5420: -  ctx - user context

5422:    Level: developer

5424: .keywords: SNES, nonlinear, compute, function

5426: .seealso: SNESSetFunction(), SNESGetFunction()
5427: @*/
5428: PetscErrorCode  SNESComputeJacobian_Matlab(SNES snes,Vec x,Mat A,Mat B,void *ctx)
5429: {
5430:   PetscErrorCode    ierr;
5431:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5432:   int               nlhs  = 2,nrhs = 6;
5433:   mxArray           *plhs[2],*prhs[6];
5434:   long long int     lx = 0,lA = 0,ls = 0, lB = 0;


5440:   /* call Matlab function in ctx with arguments x and y */

5442:   PetscMemcpy(&ls,&snes,sizeof(snes));
5443:   PetscMemcpy(&lx,&x,sizeof(x));
5444:   PetscMemcpy(&lA,A,sizeof(x));
5445:   PetscMemcpy(&lB,B,sizeof(x));
5446:   prhs[0] = mxCreateDoubleScalar((double)ls);
5447:   prhs[1] = mxCreateDoubleScalar((double)lx);
5448:   prhs[2] = mxCreateDoubleScalar((double)lA);
5449:   prhs[3] = mxCreateDoubleScalar((double)lB);
5450:   prhs[4] = mxCreateString(sctx->funcname);
5451:   prhs[5] = sctx->ctx;
5452:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeJacobianInternal");
5453:   mxGetScalar(plhs[0]);
5454:   mxDestroyArray(prhs[0]);
5455:   mxDestroyArray(prhs[1]);
5456:   mxDestroyArray(prhs[2]);
5457:   mxDestroyArray(prhs[3]);
5458:   mxDestroyArray(prhs[4]);
5459:   mxDestroyArray(plhs[0]);
5460:   mxDestroyArray(plhs[1]);
5461:   return(0);
5462: }

5466: /*
5467:    SNESSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
5468:    vector for use by the SNES routines in solving systems of nonlinear
5469:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

5471:    Logically Collective on SNES

5473:    Input Parameters:
5474: +  snes - the SNES context
5475: .  A,B - Jacobian matrices
5476: .  J - function evaluation routine
5477: -  ctx - user context

5479:    Level: developer

5481:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5483: .keywords: SNES, nonlinear, set, function

5485: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction(), J
5486: */
5487: PetscErrorCode  SNESSetJacobianMatlab(SNES snes,Mat A,Mat B,const char *J,mxArray *ctx)
5488: {
5489:   PetscErrorCode    ierr;
5490:   SNESMatlabContext *sctx;

5493:   /* currently sctx is memory bleed */
5494:   PetscNew(&sctx);
5495:   PetscStrallocpy(J,&sctx->funcname);
5496:   /*
5497:      This should work, but it doesn't
5498:   sctx->ctx = ctx;
5499:   mexMakeArrayPersistent(sctx->ctx);
5500:   */
5501:   sctx->ctx = mxDuplicateArray(ctx);
5502:   SNESSetJacobian(snes,A,B,SNESComputeJacobian_Matlab,sctx);
5503:   return(0);
5504: }

5508: /*
5509:    SNESMonitor_Matlab - Calls the function that has been set with SNESMonitorSetMatlab().

5511:    Collective on SNES

5513: .seealso: SNESSetFunction(), SNESGetFunction()
5514: @*/
5515: PetscErrorCode  SNESMonitor_Matlab(SNES snes,PetscInt it, PetscReal fnorm, void *ctx)
5516: {
5517:   PetscErrorCode    ierr;
5518:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5519:   int               nlhs  = 1,nrhs = 6;
5520:   mxArray           *plhs[1],*prhs[6];
5521:   long long int     lx = 0,ls = 0;
5522:   Vec               x  = snes->vec_sol;


5527:   PetscMemcpy(&ls,&snes,sizeof(snes));
5528:   PetscMemcpy(&lx,&x,sizeof(x));
5529:   prhs[0] = mxCreateDoubleScalar((double)ls);
5530:   prhs[1] = mxCreateDoubleScalar((double)it);
5531:   prhs[2] = mxCreateDoubleScalar((double)fnorm);
5532:   prhs[3] = mxCreateDoubleScalar((double)lx);
5533:   prhs[4] = mxCreateString(sctx->funcname);
5534:   prhs[5] = sctx->ctx;
5535:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESMonitorInternal");
5536:   mxGetScalar(plhs[0]);
5537:   mxDestroyArray(prhs[0]);
5538:   mxDestroyArray(prhs[1]);
5539:   mxDestroyArray(prhs[2]);
5540:   mxDestroyArray(prhs[3]);
5541:   mxDestroyArray(prhs[4]);
5542:   mxDestroyArray(plhs[0]);
5543:   return(0);
5544: }

5548: /*
5549:    SNESMonitorSetMatlab - Sets the monitor function from MATLAB

5551:    Level: developer

5553:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5555: .keywords: SNES, nonlinear, set, function

5557: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5558: */
5559: PetscErrorCode  SNESMonitorSetMatlab(SNES snes,const char *f,mxArray *ctx)
5560: {
5561:   PetscErrorCode    ierr;
5562:   SNESMatlabContext *sctx;

5565:   /* currently sctx is memory bleed */
5566:   PetscNew(&sctx);
5567:   PetscStrallocpy(f,&sctx->funcname);
5568:   /*
5569:      This should work, but it doesn't
5570:   sctx->ctx = ctx;
5571:   mexMakeArrayPersistent(sctx->ctx);
5572:   */
5573:   sctx->ctx = mxDuplicateArray(ctx);
5574:   SNESMonitorSet(snes,SNESMonitor_Matlab,sctx,NULL);
5575:   return(0);
5576: }

5578: #endif