Actual source code: snes.c

petsc-3.9.1 2018-04-29
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  2:  #include <petsc/private/snesimpl.h>
  3:  #include <petscdmshell.h>
  4:  #include <petscdraw.h>
  5:  #include <petscds.h>
  6:  #include <petscdmadaptor.h>
  7:  #include <petscconvest.h>

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

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

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

 19:    Logically Collective on SNES

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

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

 28:    Level: intermediate

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

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

 36: .seealso: SNESGetErrorIfNotConverged(), KSPGetErrorIfNotConverged(), KSPSetErrorIFNotConverged()
 37: @*/
 38: PetscErrorCode  SNESSetErrorIfNotConverged(SNES snes,PetscBool flg)
 39: {
 43:   snes->errorifnotconverged = flg;
 44:   return(0);
 45: }

 47: /*@
 48:    SNESGetErrorIfNotConverged - Will SNESSolve() generate an error if the solver does not converge?

 50:    Not Collective

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

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

 58:    Level: intermediate

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

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

 73: /*@
 74:     SNESSetAlwaysComputesFinalResidual - does the SNES always compute the residual at the final solution?

 76:    Logically Collective on SNES

 78:     Input Parameters:
 79: +   snes - the shell SNES
 80: -   flg - is the residual computed?

 82:    Level: advanced

 84: .seealso: SNESGetAlwaysComputesFinalResidual()
 85: @*/
 86: PetscErrorCode  SNESSetAlwaysComputesFinalResidual(SNES snes, PetscBool flg)
 87: {
 90:   snes->alwayscomputesfinalresidual = flg;
 91:   return(0);
 92: }

 94: /*@
 95:     SNESGetAlwaysComputesFinalResidual - does the SNES always compute the residual at the final solution?

 97:    Logically Collective on SNES

 99:     Input Parameter:
100: .   snes - the shell SNES

102:     Output Parameter:
103: .   flg - is the residual computed?

105:    Level: advanced

107: .seealso: SNESSetAlwaysComputesFinalResidual()
108: @*/
109: PetscErrorCode  SNESGetAlwaysComputesFinalResidual(SNES snes, PetscBool *flg)
110: {
113:   *flg = snes->alwayscomputesfinalresidual;
114:   return(0);
115: }

117: /*@
118:    SNESSetFunctionDomainError - tells SNES that the input vector to your SNESFunction is not
119:      in the functions domain. For example, negative pressure.

121:    Logically Collective on SNES

123:    Input Parameters:
124: .  snes - the SNES context

126:    Level: advanced

128: .keywords: SNES, view

130: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction
131: @*/
132: PetscErrorCode  SNESSetFunctionDomainError(SNES snes)
133: {
136:   if (snes->errorifnotconverged) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"User code indicates input vector is not in the function domain");
137:   snes->domainerror = PETSC_TRUE;
138:   return(0);
139: }

141: /*@
142:    SNESGetFunctionDomainError - Gets the status of the domain error after a call to SNESComputeFunction;

144:    Logically Collective on SNES

146:    Input Parameters:
147: .  snes - the SNES context

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

152:    Level: advanced

154: .keywords: SNES, view

156: .seealso: SNESSetFunctionDomainError(), SNESComputeFunction()
157: @*/
158: PetscErrorCode  SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
159: {
163:   *domainerror = snes->domainerror;
164:   return(0);
165: }

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

170:   Collective on PetscViewer

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

177:    Level: intermediate

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

182:   Notes for advanced users:
183:   Most users should not need to know the details of the binary storage
184:   format, since SNESLoad() and TSView() completely hide these details.
185:   But for anyone who's interested, the standard binary matrix storage
186:   format is
187: .vb
188:      has not yet been determined
189: .ve

191: .seealso: PetscViewerBinaryOpen(), SNESView(), MatLoad(), VecLoad()
192: @*/
193: PetscErrorCode  SNESLoad(SNES snes, PetscViewer viewer)
194: {
196:   PetscBool      isbinary;
197:   PetscInt       classid;
198:   char           type[256];
199:   KSP            ksp;
200:   DM             dm;
201:   DMSNES         dmsnes;

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

209:   PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
210:   if (classid != SNES_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONG,"Not SNES next in file");
211:   PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
212:   SNESSetType(snes, type);
213:   if (snes->ops->load) {
214:     (*snes->ops->load)(snes,viewer);
215:   }
216:   SNESGetDM(snes,&dm);
217:   DMGetDMSNES(dm,&dmsnes);
218:   DMSNESLoad(dmsnes,viewer);
219:   SNESGetKSP(snes,&ksp);
220:   KSPLoad(ksp,viewer);
221:   return(0);
222: }

224:  #include <petscdraw.h>
225: #if defined(PETSC_HAVE_SAWS)
226:  #include <petscviewersaws.h>
227: #endif

229: /*@C
230:    SNESView - Prints the SNES data structure.

232:    Collective on SNES

234:    Input Parameters:
235: +  SNES - the SNES context
236: -  viewer - visualization context

238:    Options Database Key:
239: .  -snes_view - Calls SNESView() at end of SNESSolve()

241:    Notes:
242:    The available visualization contexts include
243: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
244: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
245:          output where only the first processor opens
246:          the file.  All other processors send their
247:          data to the first processor to print.

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

252:    Level: beginner

254: .keywords: SNES, view

256: .seealso: PetscViewerASCIIOpen()
257: @*/
258: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
259: {
260:   SNESKSPEW      *kctx;
262:   KSP            ksp;
263:   SNESLineSearch linesearch;
264:   PetscBool      iascii,isstring,isbinary,isdraw;
265:   DMSNES         dmsnes;
266: #if defined(PETSC_HAVE_SAWS)
267:   PetscBool      issaws;
268: #endif

272:   if (!viewer) {
273:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&viewer);
274:   }

278:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
279:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
280:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
281:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
282: #if defined(PETSC_HAVE_SAWS)
283:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
284: #endif
285:   if (iascii) {
286:     SNESNormSchedule normschedule;
287:     DM               dm;
288:     PetscErrorCode   (*cJ)(SNES,Vec,Mat,Mat,void*);
289:     void             *ctx;
290:     PetscInt         tabs;

292:     PetscViewerASCIIGetTab(viewer, &tabs);
293:     PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel);
294:     PetscObjectPrintClassNamePrefixType((PetscObject)snes,viewer);
295:     if (!snes->setupcalled) {
296:       PetscViewerASCIIPrintf(viewer,"  SNES has not been set up so information may be incomplete\n");
297:     }
298:     if (snes->ops->view) {
299:       PetscViewerASCIIPushTab(viewer);
300:       (*snes->ops->view)(snes,viewer);
301:       PetscViewerASCIIPopTab(viewer);
302:     }
303:     PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
304:     PetscViewerASCIIPrintf(viewer,"  tolerances: relative=%g, absolute=%g, solution=%g\n",(double)snes->rtol,(double)snes->abstol,(double)snes->stol);
305:     if (snes->usesksp) {
306:       PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",snes->linear_its);
307:     }
308:     PetscViewerASCIIPrintf(viewer,"  total number of function evaluations=%D\n",snes->nfuncs);
309:     SNESGetNormSchedule(snes, &normschedule);
310:     if (normschedule > 0) {PetscViewerASCIIPrintf(viewer,"  norm schedule %s\n",SNESNormSchedules[normschedule]);}
311:     if (snes->gridsequence) {
312:       PetscViewerASCIIPrintf(viewer,"  total number of grid sequence refinements=%D\n",snes->gridsequence);
313:     }
314:     if (snes->ksp_ewconv) {
315:       kctx = (SNESKSPEW*)snes->kspconvctx;
316:       if (kctx) {
317:         PetscViewerASCIIPrintf(viewer,"  Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
318:         PetscViewerASCIIPrintf(viewer,"    rtol_0=%g, rtol_max=%g, threshold=%g\n",(double)kctx->rtol_0,(double)kctx->rtol_max,(double)kctx->threshold);
319:         PetscViewerASCIIPrintf(viewer,"    gamma=%g, alpha=%g, alpha2=%g\n",(double)kctx->gamma,(double)kctx->alpha,(double)kctx->alpha2);
320:       }
321:     }
322:     if (snes->lagpreconditioner == -1) {
323:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is never rebuilt\n");
324:     } else if (snes->lagpreconditioner > 1) {
325:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is rebuilt every %D new Jacobians\n",snes->lagpreconditioner);
326:     }
327:     if (snes->lagjacobian == -1) {
328:       PetscViewerASCIIPrintf(viewer,"  Jacobian is never rebuilt\n");
329:     } else if (snes->lagjacobian > 1) {
330:       PetscViewerASCIIPrintf(viewer,"  Jacobian is rebuilt every %D SNES iterations\n",snes->lagjacobian);
331:     }
332:     SNESGetDM(snes,&dm);
333:     DMSNESGetJacobian(dm,&cJ,&ctx);
334:     if (cJ == SNESComputeJacobianDefault) {
335:       PetscViewerASCIIPrintf(viewer,"  Jacobian is built using finite differences one column at a time\n");
336:     } else if (cJ == SNESComputeJacobianDefaultColor) {
337:       PetscViewerASCIIPrintf(viewer,"  Jacobian is built using finite differences with coloring\n");
338:     }
339:     PetscViewerASCIISetTab(viewer, tabs);
340:   } else if (isstring) {
341:     const char *type;
342:     SNESGetType(snes,&type);
343:     PetscViewerStringSPrintf(viewer," %-3.3s",type);
344:   } else if (isbinary) {
345:     PetscInt    classid = SNES_FILE_CLASSID;
346:     MPI_Comm    comm;
347:     PetscMPIInt rank;
348:     char        type[256];

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

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

380:     PetscObjectGetName((PetscObject)snes,&name);
381:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
382:     if (!((PetscObject)snes)->amsmem && !rank) {
383:       char       dir[1024];

385:       PetscObjectViewSAWs((PetscObject)snes,viewer);
386:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
387:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
388:       if (!snes->conv_hist) {
389:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
390:       }
391:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
392:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
393:     }
394: #endif
395:   }
396:   if (snes->linesearch) {
397:     SNESGetLineSearch(snes, &linesearch);
398:     SNESLineSearchView(linesearch, viewer);
399:   }
400:   if (snes->npc && snes->usesnpc) {
401:     SNESView(snes->npc, 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:     KSPView(ksp,viewer);
410:   }
411:   if (isdraw) {
412:     PetscDraw draw;
413:     PetscViewerDrawGetDraw(viewer,0,&draw);
414:     PetscDrawPopCurrentPoint(draw);
415:   }
416:   return(0);
417: }

419: /*
420:   We retain a list of functions that also take SNES command
421:   line options. These are called at the end SNESSetFromOptions()
422: */
423: #define MAXSETFROMOPTIONS 5
424: static PetscInt numberofsetfromoptions;
425: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

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

430:   Not Collective

432:   Input Parameter:
433: . snescheck - function that checks for options

435:   Level: developer

437: .seealso: SNESSetFromOptions()
438: @*/
439: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
440: {
442:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
443:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
444:   return(0);
445: }

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

449: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
450: {
451:   Mat            J;
452:   KSP            ksp;
453:   PC             pc;
454:   PetscBool      match;
456:   MatNullSpace   nullsp;


461:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
462:     Mat A = snes->jacobian, B = snes->jacobian_pre;
463:     MatCreateVecs(A ? A : B, NULL,&snes->vec_func);
464:   }

466:   if (version == 1) {
467:     MatCreateSNESMF(snes,&J);
468:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
469:     MatSetFromOptions(J);
470:   } else if (version == 2) {
471:     if (!snes->vec_func) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first");
472: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128) && !defined(PETSC_USE_REAL___FP16)
473:     SNESDefaultMatrixFreeCreate2(snes,snes->vec_func,&J);
474: #else
475:     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP, "matrix-free operator rutines (version 2)");
476: #endif
477:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator rutines, only version 1 and 2");

479:   /* attach any user provided null space that was on Amat to the newly created matrix free matrix */
480:   if (snes->jacobian) {
481:     MatGetNullSpace(snes->jacobian,&nullsp);
482:     if (nullsp) {
483:       MatSetNullSpace(J,nullsp);
484:     }
485:   }

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

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

514: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
515: {
516:   SNES           snes = (SNES)ctx;
518:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

521:   if (PetscLogPrintInfo) {
522:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
523:     DMGetRefineLevel(dmfine,&finelevel);
524:     DMGetCoarsenLevel(dmfine,&fineclevel);
525:     DMGetRefineLevel(dmcoarse,&coarselevel);
526:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
527:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
528:   }
529:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
530:   else {
531:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
532:     Xfine = Xfine_named;
533:   }
534:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
535:   if (Inject) {
536:     MatRestrict(Inject,Xfine,Xcoarse);
537:   } else {
538:     MatRestrict(Restrict,Xfine,Xcoarse);
539:     VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
540:   }
541:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
542:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
543:   return(0);
544: }

546: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
547: {

551:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
552:   return(0);
553: }

555: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
556:  * safely call SNESGetDM() in their residual evaluation routine. */
557: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,void *ctx)
558: {
559:   SNES           snes = (SNES)ctx;
561:   Mat            Asave = A,Bsave = B;
562:   Vec            X,Xnamed = NULL;
563:   DM             dmsave;
564:   void           *ctxsave;
565:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*) = NULL;

568:   dmsave = snes->dm;
569:   KSPGetDM(ksp,&snes->dm);
570:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
571:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
572:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
573:     X    = Xnamed;
574:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
575:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
576:     if (jac == SNESComputeJacobianDefaultColor) {
577:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,0);
578:     }
579:   }
580:   /* put the previous context back */

582:   SNESComputeJacobian(snes,X,A,B);
583:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
584:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
585:   }

587:   if (A != Asave || B != Bsave) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_SUP,"No support for changing matrices at this time");
588:   if (Xnamed) {
589:     DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
590:   }
591:   snes->dm = dmsave;
592:   return(0);
593: }

595: /*@
596:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

598:    Collective

600:    Input Arguments:
601: .  snes - snes to configure

603:    Level: developer

605: .seealso: SNESSetUp()
606: @*/
607: PetscErrorCode SNESSetUpMatrices(SNES snes)
608: {
610:   DM             dm;
611:   DMSNES         sdm;

614:   SNESGetDM(snes,&dm);
615:   DMGetDMSNES(dm,&sdm);
616:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_PLIB,"DMSNES not properly configured");
617:   else if (!snes->jacobian && snes->mf) {
618:     Mat  J;
619:     void *functx;
620:     MatCreateSNESMF(snes,&J);
621:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
622:     MatSetFromOptions(J);
623:     SNESGetFunction(snes,NULL,NULL,&functx);
624:     SNESSetJacobian(snes,J,J,0,0);
625:     MatDestroy(&J);
626:   } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
627:     Mat J,B;
628:     MatCreateSNESMF(snes,&J);
629:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
630:     MatSetFromOptions(J);
631:     DMCreateMatrix(snes->dm,&B);
632:     /* sdm->computejacobian was already set to reach here */
633:     SNESSetJacobian(snes,J,B,NULL,NULL);
634:     MatDestroy(&J);
635:     MatDestroy(&B);
636:   } else if (!snes->jacobian_pre) {
637:     PetscDS   prob;
638:     Mat       J, B;
639:     PetscBool hasPrec = PETSC_FALSE;

641:     J    = snes->jacobian;
642:     DMGetDS(dm, &prob);
643:     if (prob) {PetscDSHasJacobianPreconditioner(prob, &hasPrec);}
644:     if (J)            {PetscObjectReference((PetscObject) J);}
645:     else if (hasPrec) {DMCreateMatrix(snes->dm, &J);}
646:     DMCreateMatrix(snes->dm, &B);
647:     SNESSetJacobian(snes, J ? J : B, B, NULL, NULL);
648:     MatDestroy(&J);
649:     MatDestroy(&B);
650:   }
651:   {
652:     KSP ksp;
653:     SNESGetKSP(snes,&ksp);
654:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
655:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
656:   }
657:   return(0);
658: }

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

663:    Collective on SNES

665:    Input Parameters:
666: +  snes - SNES object you wish to monitor
667: .  name - the monitor type one is seeking
668: .  help - message indicating what monitoring is done
669: .  manual - manual page for the monitor
670: .  monitor - the monitor function
671: -  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

673:    Level: developer

675: .seealso: PetscOptionsGetViewer(), PetscOptionsGetReal(), PetscOptionsHasName(), PetscOptionsGetString(),
676:           PetscOptionsGetIntArray(), PetscOptionsGetRealArray(), PetscOptionsBool()
677:           PetscOptionsInt(), PetscOptionsString(), PetscOptionsReal(), PetscOptionsBool(),
678:           PetscOptionsName(), PetscOptionsBegin(), PetscOptionsEnd(), PetscOptionsHead(),
679:           PetscOptionsStringArray(),PetscOptionsRealArray(), PetscOptionsScalar(),
680:           PetscOptionsBoolGroupBegin(), PetscOptionsBoolGroup(), PetscOptionsBoolGroupEnd(),
681:           PetscOptionsFList(), PetscOptionsEList()
682: @*/
683: PetscErrorCode  SNESMonitorSetFromOptions(SNES snes,const char name[],const char help[], const char manual[],PetscErrorCode (*monitor)(SNES,PetscInt,PetscReal,PetscViewerAndFormat*),PetscErrorCode (*monitorsetup)(SNES,PetscViewerAndFormat*))
684: {
685:   PetscErrorCode    ierr;
686:   PetscViewer       viewer;
687:   PetscViewerFormat format;
688:   PetscBool         flg;

691:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,name,&viewer,&format,&flg);
692:   if (flg) {
693:     PetscViewerAndFormat *vf;
694:     PetscViewerAndFormatCreate(viewer,format,&vf);
695:     PetscObjectDereference((PetscObject)viewer);
696:     if (monitorsetup) {
697:       (*monitorsetup)(snes,vf);
698:     }
699:     SNESMonitorSet(snes,(PetscErrorCode (*)(SNES,PetscInt,PetscReal,void*))monitor,vf,(PetscErrorCode (*)(void**))PetscViewerAndFormatDestroy);
700:   }
701:   return(0);
702: }

704: /*@
705:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

707:    Collective on SNES

709:    Input Parameter:
710: .  snes - the SNES context

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

742:     Options Database for Eisenstat-Walker method:
743: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
744: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
745: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
746: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
747: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
748: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
749: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
750: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

752:    Notes:
753:    To see all options, run your program with the -help option or consult
754:    Users-Manual: ch_snes

756:    Level: beginner

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

760: .seealso: SNESSetOptionsPrefix()
761: @*/
762: PetscErrorCode  SNESSetFromOptions(SNES snes)
763: {
764:   PetscBool      flg,pcset,persist,set;
765:   PetscInt       i,indx,lag,grids;
766:   const char     *deft        = SNESNEWTONLS;
767:   const char     *convtests[] = {"default","skip"};
768:   SNESKSPEW      *kctx        = NULL;
769:   char           type[256], monfilename[PETSC_MAX_PATH_LEN];
771:   PCSide         pcside;
772:   const char     *optionsprefix;

776:   SNESRegisterAll();
777:   PetscObjectOptionsBegin((PetscObject)snes);
778:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
779:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
780:   if (flg) {
781:     SNESSetType(snes,type);
782:   } else if (!((PetscObject)snes)->type_name) {
783:     SNESSetType(snes,deft);
784:   }
785:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,NULL);
786:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,NULL);

788:   PetscOptionsReal("-snes_rtol","Stop if decrease in function norm less than","SNESSetTolerances",snes->rtol,&snes->rtol,NULL);
789:   PetscOptionsReal("-snes_divergence_tolerance","Stop if residual norm increases by this factor","SNESSetDivergenceTolerance",snes->divtol,&snes->divtol,NULL);
790:   PetscOptionsInt("-snes_max_it","Maximum iterations","SNESSetTolerances",snes->max_its,&snes->max_its,NULL);
791:   PetscOptionsInt("-snes_max_funcs","Maximum function evaluations","SNESSetTolerances",snes->max_funcs,&snes->max_funcs,NULL);
792:   PetscOptionsInt("-snes_max_fail","Maximum nonlinear step failures","SNESSetMaxNonlinearStepFailures",snes->maxFailures,&snes->maxFailures,NULL);
793:   PetscOptionsInt("-snes_max_linear_solve_fail","Maximum failures in linear solves allowed","SNESSetMaxLinearSolveFailures",snes->maxLinearSolveFailures,&snes->maxLinearSolveFailures,NULL);
794:   PetscOptionsBool("-snes_error_if_not_converged","Generate error if solver does not converge","SNESSetErrorIfNotConverged",snes->errorifnotconverged,&snes->errorifnotconverged,NULL);
795:   PetscOptionsBool("-snes_force_iteration","Force SNESSolve() to take at least one iteration","SNESSetForceIteration",snes->forceiteration,&snes->forceiteration,NULL);

797:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
798:   if (flg) {
799:     SNESSetLagPreconditioner(snes,lag);
800:   }
801:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
802:   if (flg) {
803:     SNESSetLagPreconditionerPersists(snes,persist);
804:   }
805:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
806:   if (flg) {
807:     SNESSetLagJacobian(snes,lag);
808:   }
809:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
810:   if (flg) {
811:     SNESSetLagJacobianPersists(snes,persist);
812:   }

814:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
815:   if (flg) {
816:     SNESSetGridSequence(snes,grids);
817:   }

819:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,2,"default",&indx,&flg);
820:   if (flg) {
821:     switch (indx) {
822:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
823:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL);    break;
824:     }
825:   }

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

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

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

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

837:   PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,NULL);
838:   PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,NULL);
839:   PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,NULL);
840:   PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,NULL);
841:   PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,NULL);
842:   PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,NULL);
843:   PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",kctx->threshold,&kctx->threshold,NULL);

845:   flg  = PETSC_FALSE;
846:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,&set);
847:   if (set && flg) {SNESMonitorCancel(snes);}

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

853:   SNESMonitorSetFromOptions(snes,"-snes_monitor_ratio","Monitor ratios of the norm of function for consecutive steps","SNESMonitorRatio",SNESMonitorRatio,SNESMonitorRatioSetUp);
854:   SNESMonitorSetFromOptions(snes,"-snes_monitor_field","Monitor norm of function (split into fields)","SNESMonitorDefaultField",SNESMonitorDefaultField,NULL);
855:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution","View solution at each iteration","SNESMonitorSolution",SNESMonitorSolution,NULL);
856:   SNESMonitorSetFromOptions(snes,"-snes_monitor_solution_update","View correction at each iteration","SNESMonitorSolutionUpdate",SNESMonitorSolutionUpdate,NULL);
857:   SNESMonitorSetFromOptions(snes,"-snes_monitor_residual","View residual at each iteration","SNESMonitorResidual",SNESMonitorResidual,NULL);
858:   SNESMonitorSetFromOptions(snes,"-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",SNESMonitorJacUpdateSpectrum,NULL);
859:   SNESMonitorSetFromOptions(snes,"-snes_monitor_fields","Monitor norm of function per field","SNESMonitorSet",SNESMonitorFields,NULL);

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


865:   flg  = PETSC_FALSE;
866:   PetscOptionsBool("-snes_monitor_lg_residualnorm","Plot function norm at each iteration","SNESMonitorLGResidualNorm",flg,&flg,NULL);
867:   if (flg) {
868:     PetscDrawLG ctx;

870:     SNESMonitorLGCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
871:     SNESMonitorSet(snes,SNESMonitorLGResidualNorm,ctx,(PetscErrorCode (*)(void**))PetscDrawLGDestroy);
872:   }
873:   flg  = PETSC_FALSE;
874:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
875:   if (flg) {
876:     PetscViewer ctx;

878:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,400,300,&ctx);
879:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
880:   }



884:   flg  = PETSC_FALSE;
885:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
886:   if (flg) {
887:     void    *functx;
888:     DM      dm;
889:     DMSNES  sdm;
890:     SNESGetDM(snes,&dm);
891:     DMGetDMSNES(dm,&sdm);
892:     sdm->jacobianctx = NULL;
893:     SNESGetFunction(snes,NULL,NULL,&functx);
894:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
895:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
896:   }

898:   flg  = PETSC_FALSE;
899:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
900:   if (flg) {
901:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
902:   }

904:   flg  = PETSC_FALSE;
905:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
906:   if (flg) {
907:     DM             dm;
908:     DMSNES         sdm;
909:     SNESGetDM(snes,&dm);
910:     DMGetDMSNES(dm,&sdm);
911:     sdm->jacobianctx = NULL;
912:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,0);
913:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
914:   }

916:   flg  = PETSC_FALSE;
917:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf_operator,&flg);
918:   if (flg && snes->mf_operator) {
919:     snes->mf_operator = PETSC_TRUE;
920:     snes->mf          = PETSC_TRUE;
921:   }
922:   flg  = PETSC_FALSE;
923:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","SNESSetUseMatrixFree",PETSC_FALSE,&snes->mf,&flg);
924:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
925:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,0);

927:   flg  = PETSC_FALSE;
928:   SNESGetNPCSide(snes,&pcside);
929:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetNPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
930:   if (flg) {SNESSetNPCSide(snes,pcside);}

932: #if defined(PETSC_HAVE_SAWS)
933:   /*
934:     Publish convergence information using SAWs
935:   */
936:   flg  = PETSC_FALSE;
937:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
938:   if (flg) {
939:     void *ctx;
940:     SNESMonitorSAWsCreate(snes,&ctx);
941:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
942:   }
943: #endif
944: #if defined(PETSC_HAVE_SAWS)
945:   {
946:   PetscBool set;
947:   flg  = PETSC_FALSE;
948:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
949:   if (set) {
950:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
951:   }
952:   }
953: #endif

955:   for (i = 0; i < numberofsetfromoptions; i++) {
956:     (*othersetfromoptions[i])(snes);
957:   }

959:   if (snes->ops->setfromoptions) {
960:     (*snes->ops->setfromoptions)(PetscOptionsObject,snes);
961:   }

963:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
964:   PetscObjectProcessOptionsHandlers(PetscOptionsObject,(PetscObject)snes);
965:   PetscOptionsEnd();

967:   if (!snes->linesearch) {
968:     SNESGetLineSearch(snes, &snes->linesearch);
969:   }
970:   SNESLineSearchSetFromOptions(snes->linesearch);

972:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
973:   KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
974:   KSPSetFromOptions(snes->ksp);

976:   /* if someone has set the SNES NPC type, create it. */
977:   SNESGetOptionsPrefix(snes, &optionsprefix);
978:   PetscOptionsHasName(((PetscObject)snes)->options,optionsprefix, "-npc_snes_type", &pcset);
979:   if (pcset && (!snes->npc)) {
980:     SNESGetNPC(snes, &snes->npc);
981:   }
982:   return(0);
983: }

985: /*@C
986:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
987:    the nonlinear solvers.

989:    Logically Collective on SNES

991:    Input Parameters:
992: +  snes - the SNES context
993: .  compute - function to compute the context
994: -  destroy - function to destroy the context

996:    Level: intermediate

998:    Notes:
999:    This function is currently not available from Fortran.

1001: .keywords: SNES, nonlinear, set, application, context

1003: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
1004: @*/
1005: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
1006: {
1009:   snes->ops->usercompute = compute;
1010:   snes->ops->userdestroy = destroy;
1011:   return(0);
1012: }

1014: /*@
1015:    SNESSetApplicationContext - Sets the optional user-defined context for
1016:    the nonlinear solvers.

1018:    Logically Collective on SNES

1020:    Input Parameters:
1021: +  snes - the SNES context
1022: -  usrP - optional user context

1024:    Level: intermediate

1026:    Fortran Notes: To use this from Fortran you must write a Fortran interface definition for this
1027:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1029: .keywords: SNES, nonlinear, set, application, context

1031: .seealso: SNESGetApplicationContext()
1032: @*/
1033: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
1034: {
1036:   KSP            ksp;

1040:   SNESGetKSP(snes,&ksp);
1041:   KSPSetApplicationContext(ksp,usrP);
1042:   snes->user = usrP;
1043:   return(0);
1044: }

1046: /*@
1047:    SNESGetApplicationContext - Gets the user-defined context for the
1048:    nonlinear solvers.

1050:    Not Collective

1052:    Input Parameter:
1053: .  snes - SNES context

1055:    Output Parameter:
1056: .  usrP - user context

1058:    Fortran Notes: To use this from Fortran you must write a Fortran interface definition for this
1059:     function that tells Fortran the Fortran derived data type that you are passing in as the ctx argument.

1061:    Level: intermediate

1063: .keywords: SNES, nonlinear, get, application, context

1065: .seealso: SNESSetApplicationContext()
1066: @*/
1067: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
1068: {
1071:   *(void**)usrP = snes->user;
1072:   return(0);
1073: }

1075: /*@
1076:    SNESSetUseMatrixFree - indicates that SNES should use matrix free finite difference matrix vector products internally to apply
1077:                           the Jacobian.

1079:    Collective on SNES

1081:    Input Parameters:
1082: +  snes - SNES context
1083: .  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored
1084: -  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used

1086:    Options Database:
1087: + -snes_mf - use matrix free for both the mat and pmat operator
1088: - -snes_mf_operator - use matrix free only for the mat operator

1090:    Level: intermediate

1092: .keywords: SNES, nonlinear, get, iteration, number,

1094: .seealso:   SNESGetUseMatrixFree(), MatCreateSNESMF()
1095: @*/
1096: PetscErrorCode  SNESSetUseMatrixFree(SNES snes,PetscBool mf_operator,PetscBool mf)
1097: {
1102:   if (mf && !mf_operator) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"If using mf must also use mf_operator");
1103:   snes->mf          = mf;
1104:   snes->mf_operator = mf_operator;
1105:   return(0);
1106: }

1108: /*@
1109:    SNESGetUseMatrixFree - indicates if the SNES uses matrix free finite difference matrix vector products to apply
1110:                           the Jacobian.

1112:    Collective on SNES

1114:    Input Parameter:
1115: .  snes - SNES context

1117:    Output Parameters:
1118: +  mf - use matrix-free for both the Amat and Pmat used by SNESSetJacobian(), both the Amat and Pmat set in SNESSetJacobian() will be ignored
1119: -  mf_operator - use matrix-free only for the Amat used by SNESSetJacobian(), this means the user provided Pmat will continue to be used

1121:    Options Database:
1122: + -snes_mf - use matrix free for both the mat and pmat operator
1123: - -snes_mf_operator - use matrix free only for the mat operator

1125:    Level: intermediate

1127: .keywords: SNES, nonlinear, get, iteration, number,

1129: .seealso:   SNESSetUseMatrixFree(), MatCreateSNESMF()
1130: @*/
1131: PetscErrorCode  SNESGetUseMatrixFree(SNES snes,PetscBool *mf_operator,PetscBool *mf)
1132: {
1135:   if (mf)          *mf          = snes->mf;
1136:   if (mf_operator) *mf_operator = snes->mf_operator;
1137:   return(0);
1138: }

1140: /*@
1141:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1142:    at this time.

1144:    Not Collective

1146:    Input Parameter:
1147: .  snes - SNES context

1149:    Output Parameter:
1150: .  iter - iteration number

1152:    Notes:
1153:    For example, during the computation of iteration 2 this would return 1.

1155:    This is useful for using lagged Jacobians (where one does not recompute the
1156:    Jacobian at each SNES iteration). For example, the code
1157: .vb
1158:       SNESGetIterationNumber(snes,&it);
1159:       if (!(it % 2)) {
1160:         [compute Jacobian here]
1161:       }
1162: .ve
1163:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1164:    recomputed every second SNES iteration.

1166:    After the SNES solve is complete this will return the number of nonlinear iterations used.

1168:    Level: intermediate

1170: .keywords: SNES, nonlinear, get, iteration, number,

1172: .seealso:   SNESGetLinearSolveIterations()
1173: @*/
1174: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1175: {
1179:   *iter = snes->iter;
1180:   return(0);
1181: }

1183: /*@
1184:    SNESSetIterationNumber - Sets the current iteration number.

1186:    Not Collective

1188:    Input Parameter:
1189: .  snes - SNES context
1190: .  iter - iteration number

1192:    Level: developer

1194: .keywords: SNES, nonlinear, set, iteration, number,

1196: .seealso:   SNESGetLinearSolveIterations()
1197: @*/
1198: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1199: {

1204:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1205:   snes->iter = iter;
1206:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1207:   return(0);
1208: }

1210: /*@
1211:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1212:    attempted by the nonlinear solver.

1214:    Not Collective

1216:    Input Parameter:
1217: .  snes - SNES context

1219:    Output Parameter:
1220: .  nfails - number of unsuccessful steps attempted

1222:    Notes:
1223:    This counter is reset to zero for each successive call to SNESSolve().

1225:    Level: intermediate

1227: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1229: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1230:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1231: @*/
1232: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1233: {
1237:   *nfails = snes->numFailures;
1238:   return(0);
1239: }

1241: /*@
1242:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1243:    attempted by the nonlinear solver before it gives up.

1245:    Not Collective

1247:    Input Parameters:
1248: +  snes     - SNES context
1249: -  maxFails - maximum of unsuccessful steps

1251:    Level: intermediate

1253: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1255: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1256:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1257: @*/
1258: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1259: {
1262:   snes->maxFailures = maxFails;
1263:   return(0);
1264: }

1266: /*@
1267:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1268:    attempted by the nonlinear solver before it gives up.

1270:    Not Collective

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

1275:    Output Parameter:
1276: .  maxFails - maximum of unsuccessful steps

1278:    Level: intermediate

1280: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1282: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1283:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1285: @*/
1286: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1287: {
1291:   *maxFails = snes->maxFailures;
1292:   return(0);
1293: }

1295: /*@
1296:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1297:      done by SNES.

1299:    Not Collective

1301:    Input Parameter:
1302: .  snes     - SNES context

1304:    Output Parameter:
1305: .  nfuncs - number of evaluations

1307:    Level: intermediate

1309:    Notes: Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1311: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1313: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1314: @*/
1315: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1316: {
1320:   *nfuncs = snes->nfuncs;
1321:   return(0);
1322: }

1324: /*@
1325:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1326:    linear solvers.

1328:    Not Collective

1330:    Input Parameter:
1331: .  snes - SNES context

1333:    Output Parameter:
1334: .  nfails - number of failed solves

1336:    Level: intermediate

1338:    Options Database Keys:
1339: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1341:    Notes:
1342:    This counter is reset to zero for each successive call to SNESSolve().

1344: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1346: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1347: @*/
1348: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1349: {
1353:   *nfails = snes->numLinearSolveFailures;
1354:   return(0);
1355: }

1357: /*@
1358:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1359:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1361:    Logically Collective on SNES

1363:    Input Parameters:
1364: +  snes     - SNES context
1365: -  maxFails - maximum allowed linear solve failures

1367:    Level: intermediate

1369:    Options Database Keys:
1370: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1372:    Notes: By default this is 0; that is SNES returns on the first failed linear solve

1374: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1376: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations()
1377: @*/
1378: PetscErrorCode  SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1379: {
1383:   snes->maxLinearSolveFailures = maxFails;
1384:   return(0);
1385: }

1387: /*@
1388:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1389:      are allowed before SNES terminates

1391:    Not Collective

1393:    Input Parameter:
1394: .  snes     - SNES context

1396:    Output Parameter:
1397: .  maxFails - maximum of unsuccessful solves allowed

1399:    Level: intermediate

1401:    Notes: By default this is 1; that is SNES returns on the first failed linear solve

1403: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1405: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1406: @*/
1407: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1408: {
1412:   *maxFails = snes->maxLinearSolveFailures;
1413:   return(0);
1414: }

1416: /*@
1417:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1418:    used by the nonlinear solver.

1420:    Not Collective

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

1425:    Output Parameter:
1426: .  lits - number of linear iterations

1428:    Notes:
1429:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1431:    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
1432:    then call KSPGetIterationNumber() after the failed solve.

1434:    Level: intermediate

1436: .keywords: SNES, nonlinear, get, number, linear, iterations

1438: .seealso:  SNESGetIterationNumber(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1439: @*/
1440: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1441: {
1445:   *lits = snes->linear_its;
1446:   return(0);
1447: }

1449: /*@
1450:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1451:    are reset every time SNESSolve() is called.

1453:    Logically Collective on SNES

1455:    Input Parameter:
1456: +  snes - SNES context
1457: -  reset - whether to reset the counters or not

1459:    Notes:
1460:    This defaults to PETSC_TRUE

1462:    Level: developer

1464: .keywords: SNES, nonlinear, set, reset, number, linear, iterations

1466: .seealso:  SNESGetNumberFunctionEvals(), SNESGetLinearSolveIterations(), SNESGetNPC()
1467: @*/
1468: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1469: {
1473:   snes->counters_reset = reset;
1474:   return(0);
1475: }


1478: /*@
1479:    SNESSetKSP - Sets a KSP context for the SNES object to use

1481:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1483:    Input Parameters:
1484: +  snes - the SNES context
1485: -  ksp - the KSP context

1487:    Notes:
1488:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1489:    so this routine is rarely needed.

1491:    The KSP object that is already in the SNES object has its reference count
1492:    decreased by one.

1494:    Level: developer

1496: .keywords: SNES, nonlinear, get, KSP, context

1498: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1499: @*/
1500: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1501: {

1508:   PetscObjectReference((PetscObject)ksp);
1509:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1510:   snes->ksp = ksp;
1511:   return(0);
1512: }

1514: /* -----------------------------------------------------------*/
1515: /*@
1516:    SNESCreate - Creates a nonlinear solver context.

1518:    Collective on MPI_Comm

1520:    Input Parameters:
1521: .  comm - MPI communicator

1523:    Output Parameter:
1524: .  outsnes - the new SNES context

1526:    Options Database Keys:
1527: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1528:                and no preconditioning matrix
1529: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1530:                products, and a user-provided preconditioning matrix
1531:                as set by SNESSetJacobian()
1532: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1534:    Level: beginner

1536:    Developer Notes: SNES always creates a KSP object even though many SNES methods do not use it. This is
1537:                     unfortunate and should be fixed at some point. The flag snes->usesksp indicates if the
1538:                     particular method does use KSP and regulates if the information about the KSP is printed
1539:                     in SNESView(). TSSetFromOptions() does call SNESSetFromOptions() which can lead to users being confused
1540:                     by help messages about meaningless SNES options.

1542:                     SNES always creates the snes->kspconvctx even though it is used by only one type. This should
1543:                     be fixed.

1545: .keywords: SNES, nonlinear, create, context

1547: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner()

1549: @*/
1550: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1551: {
1553:   SNES           snes;
1554:   SNESKSPEW      *kctx;

1558:   *outsnes = NULL;
1559:   SNESInitializePackage();

1561:   PetscHeaderCreate(snes,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1563:   snes->ops->converged    = SNESConvergedDefault;
1564:   snes->usesksp           = PETSC_TRUE;
1565:   snes->tolerancesset     = PETSC_FALSE;
1566:   snes->max_its           = 50;
1567:   snes->max_funcs         = 10000;
1568:   snes->norm              = 0.0;
1569:   snes->normschedule      = SNES_NORM_ALWAYS;
1570:   snes->functype          = SNES_FUNCTION_DEFAULT;
1571: #if defined(PETSC_USE_REAL_SINGLE)
1572:   snes->rtol              = 1.e-5;
1573: #else
1574:   snes->rtol              = 1.e-8;
1575: #endif
1576:   snes->ttol              = 0.0;
1577: #if defined(PETSC_USE_REAL_SINGLE)
1578:   snes->abstol            = 1.e-25;
1579: #else
1580:   snes->abstol            = 1.e-50;
1581: #endif
1582: #if defined(PETSC_USE_REAL_SINGLE)
1583:   snes->stol              = 1.e-5;
1584: #else
1585:   snes->stol              = 1.e-8;
1586: #endif
1587: #if defined(PETSC_USE_REAL_SINGLE)
1588:   snes->deltatol          = 1.e-6;
1589: #else
1590:   snes->deltatol          = 1.e-12;
1591: #endif
1592:   snes->divtol            = 1.e4;
1593:   snes->rnorm0            = 0;
1594:   snes->nfuncs            = 0;
1595:   snes->numFailures       = 0;
1596:   snes->maxFailures       = 1;
1597:   snes->linear_its        = 0;
1598:   snes->lagjacobian       = 1;
1599:   snes->jac_iter          = 0;
1600:   snes->lagjac_persist    = PETSC_FALSE;
1601:   snes->lagpreconditioner = 1;
1602:   snes->pre_iter          = 0;
1603:   snes->lagpre_persist    = PETSC_FALSE;
1604:   snes->numbermonitors    = 0;
1605:   snes->data              = 0;
1606:   snes->setupcalled       = PETSC_FALSE;
1607:   snes->ksp_ewconv        = PETSC_FALSE;
1608:   snes->nwork             = 0;
1609:   snes->work              = 0;
1610:   snes->nvwork            = 0;
1611:   snes->vwork             = 0;
1612:   snes->conv_hist_len     = 0;
1613:   snes->conv_hist_max     = 0;
1614:   snes->conv_hist         = NULL;
1615:   snes->conv_hist_its     = NULL;
1616:   snes->conv_hist_reset   = PETSC_TRUE;
1617:   snes->counters_reset    = PETSC_TRUE;
1618:   snes->vec_func_init_set = PETSC_FALSE;
1619:   snes->reason            = SNES_CONVERGED_ITERATING;
1620:   snes->npcside           = PC_RIGHT;

1622:   snes->mf          = PETSC_FALSE;
1623:   snes->mf_operator = PETSC_FALSE;
1624:   snes->mf_version  = 1;

1626:   snes->numLinearSolveFailures = 0;
1627:   snes->maxLinearSolveFailures = 1;

1629:   snes->vizerotolerance = 1.e-8;

1631:   /* Set this to true if the implementation of SNESSolve_XXX does compute the residual at the final solution. */
1632:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

1634:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1635:   PetscNewLog(snes,&kctx);

1637:   snes->kspconvctx  = (void*)kctx;
1638:   kctx->version     = 2;
1639:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1640:                              this was too large for some test cases */
1641:   kctx->rtol_last   = 0.0;
1642:   kctx->rtol_max    = .9;
1643:   kctx->gamma       = 1.0;
1644:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1645:   kctx->alpha2      = kctx->alpha;
1646:   kctx->threshold   = .1;
1647:   kctx->lresid_last = 0.0;
1648:   kctx->norm_last   = 0.0;

1650:   *outsnes = snes;
1651:   return(0);
1652: }

1654: /*MC
1655:     SNESFunction - Functional form used to convey the nonlinear function to be solved by SNES

1657:      Synopsis:
1658:      #include "petscsnes.h"
1659:      PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1661:      Input Parameters:
1662: +     snes - the SNES context
1663: .     x    - state at which to evaluate residual
1664: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1666:      Output Parameter:
1667: .     f  - vector to put residual (function value)

1669:    Level: intermediate

1671: .seealso:   SNESSetFunction(), SNESGetFunction()
1672: M*/

1674: /*@C
1675:    SNESSetFunction - Sets the function evaluation routine and function
1676:    vector for use by the SNES routines in solving systems of nonlinear
1677:    equations.

1679:    Logically Collective on SNES

1681:    Input Parameters:
1682: +  snes - the SNES context
1683: .  r - vector to store function value
1684: .  f - function evaluation routine; see SNESFunction for calling sequence details
1685: -  ctx - [optional] user-defined context for private data for the
1686:          function evaluation routine (may be NULL)

1688:    Notes:
1689:    The Newton-like methods typically solve linear systems of the form
1690: $      f'(x) x = -f(x),
1691:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1693:    Level: beginner

1695: .keywords: SNES, nonlinear, set, function

1697: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1698: @*/
1699: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1700: {
1702:   DM             dm;

1706:   if (r) {
1709:     PetscObjectReference((PetscObject)r);
1710:     VecDestroy(&snes->vec_func);

1712:     snes->vec_func = r;
1713:   }
1714:   SNESGetDM(snes,&dm);
1715:   DMSNESSetFunction(dm,f,ctx);
1716:   return(0);
1717: }


1720: /*@C
1721:    SNESSetInitialFunction - Sets the function vector to be used as the
1722:    function norm at the initialization of the method.  In some
1723:    instances, the user has precomputed the function before calling
1724:    SNESSolve.  This function allows one to avoid a redundant call
1725:    to SNESComputeFunction in that case.

1727:    Logically Collective on SNES

1729:    Input Parameters:
1730: +  snes - the SNES context
1731: -  f - vector to store function value

1733:    Notes:
1734:    This should not be modified during the solution procedure.

1736:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1738:    Level: developer

1740: .keywords: SNES, nonlinear, set, function

1742: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1743: @*/
1744: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1745: {
1747:   Vec            vec_func;

1753:   if (snes->npcside== PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1754:     snes->vec_func_init_set = PETSC_FALSE;
1755:     return(0);
1756:   }
1757:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1758:   VecCopy(f, vec_func);

1760:   snes->vec_func_init_set = PETSC_TRUE;
1761:   return(0);
1762: }

1764: /*@
1765:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1766:    of the SNES method.

1768:    Logically Collective on SNES

1770:    Input Parameters:
1771: +  snes - the SNES context
1772: -  normschedule - the frequency of norm computation

1774:    Options Database Key:
1775: .  -snes_norm_schedule <none, always, initialonly, finalonly, initalfinalonly>

1777:    Notes:
1778:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1779:    of the nonlinear function and the taking of its norm at every iteration to
1780:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1781:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1782:    may either be monitored for convergence or not.  As these are often used as nonlinear
1783:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1784:    their solution.

1786:    Level: developer

1788: .keywords: SNES, nonlinear, set, function, norm, type

1790: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1791: @*/
1792: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1793: {
1796:   snes->normschedule = normschedule;
1797:   return(0);
1798: }


1801: /*@
1802:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1803:    of the SNES method.

1805:    Logically Collective on SNES

1807:    Input Parameters:
1808: +  snes - the SNES context
1809: -  normschedule - the type of the norm used

1811:    Level: advanced

1813: .keywords: SNES, nonlinear, set, function, norm, type

1815: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1816: @*/
1817: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1818: {
1821:   *normschedule = snes->normschedule;
1822:   return(0);
1823: }


1826: /*@
1827:   SNESSetFunctionNorm - Sets the last computed residual norm.

1829:   Logically Collective on SNES

1831:   Input Parameters:
1832: + snes - the SNES context

1834: - normschedule - the frequency of norm computation

1836:   Level: developer

1838: .keywords: SNES, nonlinear, set, function, norm, type
1839: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1840: @*/
1841: PetscErrorCode SNESSetFunctionNorm(SNES snes, PetscReal norm)
1842: {
1845:   snes->norm = norm;
1846:   return(0);
1847: }

1849: /*@
1850:   SNESGetFunctionNorm - Gets the last computed norm of the residual

1852:   Not Collective

1854:   Input Parameter:
1855: . snes - the SNES context

1857:   Output Parameter:
1858: . norm - the last computed residual norm

1860:   Level: developer

1862: .keywords: SNES, nonlinear, set, function, norm, type
1863: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1864: @*/
1865: PetscErrorCode SNESGetFunctionNorm(SNES snes, PetscReal *norm)
1866: {
1870:   *norm = snes->norm;
1871:   return(0);
1872: }

1874: /*@C
1875:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
1876:    of the SNES method.

1878:    Logically Collective on SNES

1880:    Input Parameters:
1881: +  snes - the SNES context
1882: -  normschedule - the frequency of norm computation

1884:    Notes:
1885:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1886:    of the nonlinear function and the taking of its norm at every iteration to
1887:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1888:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1889:    may either be monitored for convergence or not.  As these are often used as nonlinear
1890:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1891:    their solution.

1893:    Level: developer

1895: .keywords: SNES, nonlinear, set, function, norm, type

1897: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1898: @*/
1899: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
1900: {
1903:   snes->functype = type;
1904:   return(0);
1905: }


1908: /*@C
1909:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
1910:    of the SNES method.

1912:    Logically Collective on SNES

1914:    Input Parameters:
1915: +  snes - the SNES context
1916: -  normschedule - the type of the norm used

1918:    Level: advanced

1920: .keywords: SNES, nonlinear, set, function, norm, type

1922: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1923: @*/
1924: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
1925: {
1928:   *type = snes->functype;
1929:   return(0);
1930: }

1932: /*MC
1933:     SNESNGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

1935:      Synopsis:
1936:      #include <petscsnes.h>
1937: $    SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);

1939: +  X   - solution vector
1940: .  B   - RHS vector
1941: -  ctx - optional user-defined Gauss-Seidel context

1943:    Level: intermediate

1945: .seealso:   SNESSetNGS(), SNESGetNGS()
1946: M*/

1948: /*@C
1949:    SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
1950:    use with composed nonlinear solvers.

1952:    Input Parameters:
1953: +  snes   - the SNES context
1954: .  f - function evaluation routine to apply Gauss-Seidel see SNESNGSFunction
1955: -  ctx    - [optional] user-defined context for private data for the
1956:             smoother evaluation routine (may be NULL)

1958:    Notes:
1959:    The NGS routines are used by the composed nonlinear solver to generate
1960:     a problem appropriate update to the solution, particularly FAS.

1962:    Level: intermediate

1964: .keywords: SNES, nonlinear, set, Gauss-Seidel

1966: .seealso: SNESGetFunction(), SNESComputeNGS()
1967: @*/
1968: PetscErrorCode SNESSetNGS(SNES snes,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1969: {
1971:   DM             dm;

1975:   SNESGetDM(snes,&dm);
1976:   DMSNESSetNGS(dm,f,ctx);
1977:   return(0);
1978: }

1980: PETSC_EXTERN PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
1981: {
1983:   DM             dm;
1984:   DMSNES         sdm;

1987:   SNESGetDM(snes,&dm);
1988:   DMGetDMSNES(dm,&sdm);
1989:   /*  A(x)*x - b(x) */
1990:   if (sdm->ops->computepfunction) {
1991:     (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
1992:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");

1994:   if (sdm->ops->computepjacobian) {
1995:     (*sdm->ops->computepjacobian)(snes,x,snes->jacobian,snes->jacobian_pre,sdm->pctx);
1996:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard matrix.");
1997:   VecScale(f,-1.0);
1998:   MatMultAdd(snes->jacobian,x,f,f);
1999:   return(0);
2000: }

2002: PETSC_EXTERN PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat J,Mat B,void *ctx)
2003: {
2005:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
2006:   return(0);
2007: }

2009: /*@C
2010:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

2012:    Logically Collective on SNES

2014:    Input Parameters:
2015: +  snes - the SNES context
2016: .  r - vector to store function value
2017: .  b - function evaluation routine
2018: .  Amat - matrix with which A(x) x - b(x) is to be computed
2019: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
2020: .  J  - function to compute matrix value, see SNESJacobianFunction for details on its calling sequence
2021: -  ctx - [optional] user-defined context for private data for the
2022:          function evaluation routine (may be NULL)

2024:    Notes:
2025:     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
2026:     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.

2028:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

2030: $     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}
2031: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

2033:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

2035:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
2036:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

2038:    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
2039:    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
2040:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

2042:    Level: intermediate

2044: .keywords: SNES, nonlinear, set, function

2046: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard(), SNESJacobianFunction
2047: @*/
2048: 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)
2049: {
2051:   DM             dm;

2055:   SNESGetDM(snes, &dm);
2056:   DMSNESSetPicard(dm,b,J,ctx);
2057:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
2058:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
2059:   return(0);
2060: }

2062: /*@C
2063:    SNESGetPicard - Returns the context for the Picard iteration

2065:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

2067:    Input Parameter:
2068: .  snes - the SNES context

2070:    Output Parameter:
2071: +  r - the function (or NULL)
2072: .  f - the function (or NULL); see SNESFunction for calling sequence details
2073: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
2074: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
2075: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
2076: -  ctx - the function context (or NULL)

2078:    Level: advanced

2080: .keywords: SNES, nonlinear, get, function

2082: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
2083: @*/
2084: 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)
2085: {
2087:   DM             dm;

2091:   SNESGetFunction(snes,r,NULL,NULL);
2092:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
2093:   SNESGetDM(snes,&dm);
2094:   DMSNESGetPicard(dm,f,J,ctx);
2095:   return(0);
2096: }

2098: /*@C
2099:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

2101:    Logically Collective on SNES

2103:    Input Parameters:
2104: +  snes - the SNES context
2105: .  func - function evaluation routine
2106: -  ctx - [optional] user-defined context for private data for the
2107:          function evaluation routine (may be NULL)

2109:    Calling sequence of func:
2110: $    func (SNES snes,Vec x,void *ctx);

2112: .  f - function vector
2113: -  ctx - optional user-defined function context

2115:    Level: intermediate

2117: .keywords: SNES, nonlinear, set, function

2119: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
2120: @*/
2121: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
2122: {
2125:   if (func) snes->ops->computeinitialguess = func;
2126:   if (ctx)  snes->initialguessP            = ctx;
2127:   return(0);
2128: }

2130: /* --------------------------------------------------------------- */
2131: /*@C
2132:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
2133:    it assumes a zero right hand side.

2135:    Logically Collective on SNES

2137:    Input Parameter:
2138: .  snes - the SNES context

2140:    Output Parameter:
2141: .  rhs - the right hand side vector or NULL if the right hand side vector is null

2143:    Level: intermediate

2145: .keywords: SNES, nonlinear, get, function, right hand side

2147: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2148: @*/
2149: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2150: {
2154:   *rhs = snes->vec_rhs;
2155:   return(0);
2156: }

2158: /*@
2159:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2161:    Collective on SNES

2163:    Input Parameters:
2164: +  snes - the SNES context
2165: -  x - input vector

2167:    Output Parameter:
2168: .  y - function vector, as set by SNESSetFunction()

2170:    Notes:
2171:    SNESComputeFunction() is typically used within nonlinear solvers
2172:    implementations, so most users would not generally call this routine
2173:    themselves.

2175:    Level: developer

2177: .keywords: SNES, nonlinear, compute, function

2179: .seealso: SNESSetFunction(), SNESGetFunction()
2180: @*/
2181: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2182: {
2184:   DM             dm;
2185:   DMSNES         sdm;

2193:   VecValidValues(x,2,PETSC_TRUE);

2195:   SNESGetDM(snes,&dm);
2196:   DMGetDMSNES(dm,&sdm);
2197:   if (sdm->ops->computefunction) {
2198:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2199:       PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2200:     }
2201:     VecLockPush(x);
2202:     PetscStackPush("SNES user function");
2203:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2204:     PetscStackPop;
2205:     VecLockPop(x);
2206:     if (sdm->ops->computefunction != SNESObjectiveComputeFunctionDefaultFD) {
2207:       PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2208:     }
2209:   } else if (snes->vec_rhs) {
2210:     MatMult(snes->jacobian, x, y);
2211:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2212:   if (snes->vec_rhs) {
2213:     VecAXPY(y,-1.0,snes->vec_rhs);
2214:   }
2215:   snes->nfuncs++;
2216:   /*
2217:      domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2218:      propagate the value to all processes
2219:   */
2220:   if (snes->domainerror) {
2221:     VecSetInf(y);
2222:   }
2223:   return(0);
2224: }

2226: /*@
2227:    SNESComputeNGS - Calls the Gauss-Seidel function that has been set with  SNESSetNGS().

2229:    Collective on SNES

2231:    Input Parameters:
2232: +  snes - the SNES context
2233: .  x - input vector
2234: -  b - rhs vector

2236:    Output Parameter:
2237: .  x - new solution vector

2239:    Notes:
2240:    SNESComputeNGS() is typically used within composed nonlinear solver
2241:    implementations, so most users would not generally call this routine
2242:    themselves.

2244:    Level: developer

2246: .keywords: SNES, nonlinear, compute, function

2248: .seealso: SNESSetNGS(), SNESComputeFunction()
2249: @*/
2250: PetscErrorCode  SNESComputeNGS(SNES snes,Vec b,Vec x)
2251: {
2253:   DM             dm;
2254:   DMSNES         sdm;

2262:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2263:   PetscLogEventBegin(SNES_NGSEval,snes,x,b,0);
2264:   SNESGetDM(snes,&dm);
2265:   DMGetDMSNES(dm,&sdm);
2266:   if (sdm->ops->computegs) {
2267:     if (b) {VecLockPush(b);}
2268:     PetscStackPush("SNES user NGS");
2269:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2270:     PetscStackPop;
2271:     if (b) {VecLockPop(b);}
2272:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2273:   PetscLogEventEnd(SNES_NGSEval,snes,x,b,0);
2274:   return(0);
2275: }

2277: PetscErrorCode SNESTestJacobian(SNES snes)
2278: {
2279:   Mat            A = snes->jacobian,B,C;
2280:   Vec            x = snes->vec_sol,f = snes->vec_func;
2282:   PetscReal      nrm,gnorm;
2283:   PetscReal      threshold = 1.e-5;
2284:   PetscInt       m,n,M,N;
2285:   void           *functx;
2286:   PetscBool      complete_print = PETSC_FALSE,threshold_print = PETSC_FALSE,test = PETSC_FALSE;
2287:   PetscViewer    viewer;
2288:   MPI_Comm       comm;
2289:   PetscInt       tabs;

2292:   PetscObjectOptionsBegin((PetscObject)snes);
2293:   PetscOptionsBool("-snes_test_jacobian","Compare hand-coded and finite difference Jacobians","None",test,&test,NULL);
2294:   PetscOptionsBool("-snes_test_jacobian_display","Display difference between hand-coded and finite difference Jacobians","None",complete_print,&complete_print,NULL);
2295:   PetscOptionsReal("-snes_test_jacobian_display_threshold", "Display difference between hand-coded and finite difference Jacobians which exceed input threshold", "None", threshold, &threshold, &threshold_print);
2296:   PetscOptionsEnd();
2297:   if (!test) return(0);

2299:   PetscObjectGetComm((PetscObject)snes,&comm);
2300:   PetscViewerASCIIGetStdout(comm,&viewer);
2301:   PetscViewerASCIIGetTab(viewer, &tabs);
2302:   PetscViewerASCIISetTab(viewer, ((PetscObject)snes)->tablevel);
2303:   if (A != snes->jacobian_pre) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Cannot test with alternative preconditioner");

2305:   PetscViewerASCIIPrintf(viewer,"  Testing hand-coded Jacobian, if the ratio is\n");
2306:   PetscViewerASCIIPrintf(viewer,"    O(1.e-8), the hand-coded Jacobian is probably correct.\n");
2307:   if (!complete_print) {
2308:     PetscViewerASCIIPrintf(viewer,"  Run with -snes_test_jacobian_display to show difference\n");
2309:     PetscViewerASCIIPrintf(viewer,"    of hand-coded and finite difference Jacobian.\n");
2310:     PetscViewerASCIIPrintf(viewer,"  Run with -snes_test_jacobian_display_threshold to show difference\n");
2311:     PetscViewerASCIIPrintf(viewer,"    of hand-coded and finite difference Jacobian entries great than threshold.\n");
2312:   }

2314:   /* evaluate the function at this point because SNESComputeJacobianDefaultColor() assumes that the function has been evaluated and put into snes->vec_func */
2315:   SNESComputeFunction(snes,x,f);
2316:   A    = snes->jacobian_pre;

2318:   MatCreate(PetscObjectComm((PetscObject)A),&B);
2319:   MatGetSize(A,&M,&N);
2320:   MatGetLocalSize(A,&m,&n);
2321:   MatSetSizes(B,m,n,M,N);
2322:   MatSetType(B,((PetscObject)A)->type_name);
2323:   MatSetUp(B);
2324:   MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);

2326:   SNESGetFunction(snes,NULL,NULL,&functx);
2327:   SNESComputeJacobianDefault(snes,x,B,B,functx);
2328:   if (complete_print) {
2329:     PetscViewerASCIIPrintf(viewer,"  Finite difference Jacobian\n");
2330:     MatView(B,viewer);
2331:   }
2332:   /* compare */
2333:   MatAYPX(B,-1.0,A,DIFFERENT_NONZERO_PATTERN);
2334:   MatNorm(B,NORM_FROBENIUS,&nrm);
2335:   MatNorm(A,NORM_FROBENIUS,&gnorm);
2336:   if (complete_print) {
2337:     PetscViewerASCIIPrintf(viewer,"Hand-coded Jacobian\n");
2338:     PetscObjectGetComm((PetscObject)B,&comm);
2339:     PetscViewerASCIIGetStdout(comm,&viewer);
2340:     MatView(A,viewer);
2341:     PetscViewerASCIIPrintf(viewer,"  Hand-coded minus finite-difference Jacobian\n");
2342:     MatView(B,viewer);
2343:   }

2345:   if (threshold_print) {
2346:     PetscInt          Istart, Iend, *ccols, bncols, cncols, j, row;
2347:     PetscScalar       *cvals;
2348:     const PetscInt    *bcols;
2349:     const PetscScalar *bvals;

2351:     MatCreate(PetscObjectComm((PetscObject)A),&C);
2352:     MatSetSizes(C,m,n,M,N);
2353:     MatSetType(C,((PetscObject)A)->type_name);
2354:     MatSetUp(C);
2355:     MatSetOption(C,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);
2356:     MatGetOwnershipRange(B,&Istart,&Iend);

2358:     for (row = Istart; row < Iend; row++) {
2359:       MatGetRow(B,row,&bncols,&bcols,&bvals);
2360:       PetscMalloc2(bncols,&ccols,bncols,&cvals);
2361:       for (j = 0, cncols = 0; j < bncols; j++) {
2362:         if (PetscAbsScalar(bvals[j]) > threshold) {
2363:           ccols[cncols] = bcols[j];
2364:           cvals[cncols] = bvals[j];
2365:           cncols += 1;
2366:         }
2367:       }
2368:       if(cncols) {
2369:         MatSetValues(C,1,&row,cncols,ccols,cvals,INSERT_VALUES);
2370:       }
2371:       MatRestoreRow(B,row,&bncols,&bcols,&bvals);
2372:       PetscFree2(ccols,cvals);
2373:     }
2374:     MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
2375:     MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

2377:     PetscViewerASCIIPrintf(viewer,"  Entries where difference is over threshold\n");
2378:     MatView(C,viewer);
2379:     MatDestroy(&C);
2380:   }

2382:   if (!gnorm) gnorm = 1; /* just in case */
2383:   PetscViewerASCIIPrintf(viewer,"||J - Jfd||_F/||J||_F %g, ||J - Jfd||_F %g\n",(double)(nrm/gnorm),(double)nrm);
2384:   MatDestroy(&B);
2385:   PetscViewerASCIISetTab(viewer,tabs);
2386:   return(0);
2387: }

2389: /*@
2390:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2392:    Collective on SNES and Mat

2394:    Input Parameters:
2395: +  snes - the SNES context
2396: -  x - input vector

2398:    Output Parameters:
2399: +  A - Jacobian matrix
2400: -  B - optional preconditioning matrix

2402:   Options Database Keys:
2403: +    -snes_lag_preconditioner <lag>
2404: .    -snes_lag_jacobian <lag>
2405: .    -snes_test_jacobian - compare the user provided Jacobian with one compute via finite differences to check for errors
2406: .    -snes_test_jacobian_display - display the user provided Jacobian, the finite difference Jacobian and the difference between them to help users detect the location of errors in the user provided Jacobian
2407: .    -snes_test_jacobian_display_threshold <numerical value>  - display entries in the difference between the user provided Jacobian and finite difference Jacobian that are greater than a certain value to help users detect errors
2408: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2409: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2410: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2411: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2412: .    -snes_compare_coloring - Compute the finite difference Jacobian using coloring and display norms of difference
2413: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2414: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2415: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2416: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2417: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2418: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2421:    Notes:
2422:    Most users should not need to explicitly call this routine, as it
2423:    is used internally within the nonlinear solvers.

2425:    Developer Notes: This has duplicative ways of checking the accuracy of the user provided Jacobian (see the options above). This is for historical reasons, the routine SNESTestJacobian() use to used 
2426:       for with the SNESType of test that has been removed.

2428:    Level: developer

2430: .keywords: SNES, compute, Jacobian, matrix

2432: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2433: @*/
2434: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat A,Mat B)
2435: {
2437:   PetscBool      flag;
2438:   DM             dm;
2439:   DMSNES         sdm;
2440:   KSP            ksp;

2446:   VecValidValues(X,2,PETSC_TRUE);
2447:   SNESGetDM(snes,&dm);
2448:   DMGetDMSNES(dm,&sdm);

2450:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2452:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2454:   if (snes->lagjacobian == -2) {
2455:     snes->lagjacobian = -1;

2457:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2458:   } else if (snes->lagjacobian == -1) {
2459:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2460:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2461:     if (flag) {
2462:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2463:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2464:     }
2465:     return(0);
2466:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2467:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2468:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2469:     if (flag) {
2470:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2471:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2472:     }
2473:     return(0);
2474:   }
2475:   if (snes->npc && snes->npcside== PC_LEFT) {
2476:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2477:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2478:       return(0);
2479:   }

2481:   PetscLogEventBegin(SNES_JacobianEval,snes,X,A,B);
2482:   VecLockPush(X);
2483:   PetscStackPush("SNES user Jacobian function");
2484:   (*sdm->ops->computejacobian)(snes,X,A,B,sdm->jacobianctx);
2485:   PetscStackPop;
2486:   VecLockPop(X);
2487:   PetscLogEventEnd(SNES_JacobianEval,snes,X,A,B);

2489:   /* the next line ensures that snes->ksp exists */
2490:   SNESGetKSP(snes,&ksp);
2491:   if (snes->lagpreconditioner == -2) {
2492:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");
2493:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2494:     snes->lagpreconditioner = -1;
2495:   } else if (snes->lagpreconditioner == -1) {
2496:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2497:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2498:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2499:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2500:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2501:   } else {
2502:     PetscInfo(snes,"Rebuilding preconditioner\n");
2503:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2504:   }

2506:   SNESTestJacobian(snes);
2507:   /* make sure user returned a correct Jacobian and preconditioner */
2510:   {
2511:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2512:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_explicit",NULL,NULL,&flag);
2513:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",NULL,NULL,&flag_draw);
2514:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",NULL,NULL,&flag_contour);
2515:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_operator",NULL,NULL,&flag_operator);
2516:     if (flag || flag_draw || flag_contour) {
2517:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2518:       PetscViewer  vdraw,vstdout;
2519:       PetscBool    flg;
2520:       if (flag_operator) {
2521:         MatComputeExplicitOperator(A,&Bexp_mine);
2522:         Bexp = Bexp_mine;
2523:       } else {
2524:         /* See if the preconditioning matrix can be viewed and added directly */
2525:         PetscObjectTypeCompareAny((PetscObject)B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2526:         if (flg) Bexp = B;
2527:         else {
2528:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2529:           MatComputeExplicitOperator(B,&Bexp_mine);
2530:           Bexp = Bexp_mine;
2531:         }
2532:       }
2533:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2534:       SNESComputeJacobianDefault(snes,X,FDexp,FDexp,NULL);
2535:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2536:       if (flag_draw || flag_contour) {
2537:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2538:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2539:       } else vdraw = NULL;
2540:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2541:       if (flag) {MatView(Bexp,vstdout);}
2542:       if (vdraw) {MatView(Bexp,vdraw);}
2543:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2544:       if (flag) {MatView(FDexp,vstdout);}
2545:       if (vdraw) {MatView(FDexp,vdraw);}
2546:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2547:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2548:       if (flag) {MatView(FDexp,vstdout);}
2549:       if (vdraw) {              /* Always use contour for the difference */
2550:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2551:         MatView(FDexp,vdraw);
2552:         PetscViewerPopFormat(vdraw);
2553:       }
2554:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2555:       PetscViewerDestroy(&vdraw);
2556:       MatDestroy(&Bexp_mine);
2557:       MatDestroy(&FDexp);
2558:     }
2559:   }
2560:   {
2561:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2562:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2563:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring",NULL,NULL,&flag);
2564:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_display",NULL,NULL,&flag_display);
2565:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",NULL,NULL,&flag_draw);
2566:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",NULL,NULL,&flag_contour);
2567:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",NULL,NULL,&flag_threshold);
2568:     if (flag_threshold) {
2569:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2570:       PetscOptionsGetReal(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2571:     }
2572:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2573:       Mat            Bfd;
2574:       PetscViewer    vdraw,vstdout;
2575:       MatColoring    coloring;
2576:       ISColoring     iscoloring;
2577:       MatFDColoring  matfdcoloring;
2578:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2579:       void           *funcctx;
2580:       PetscReal      norm1,norm2,normmax;

2582:       MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2583:       MatColoringCreate(Bfd,&coloring);
2584:       MatColoringSetType(coloring,MATCOLORINGSL);
2585:       MatColoringSetFromOptions(coloring);
2586:       MatColoringApply(coloring,&iscoloring);
2587:       MatColoringDestroy(&coloring);
2588:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2589:       MatFDColoringSetFromOptions(matfdcoloring);
2590:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2591:       ISColoringDestroy(&iscoloring);

2593:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2594:       SNESGetFunction(snes,NULL,&func,&funcctx);
2595:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2596:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2597:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2598:       MatFDColoringSetFromOptions(matfdcoloring);
2599:       MatFDColoringApply(Bfd,matfdcoloring,X,snes);
2600:       MatFDColoringDestroy(&matfdcoloring);

2602:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2603:       if (flag_draw || flag_contour) {
2604:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2605:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2606:       } else vdraw = NULL;
2607:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2608:       if (flag_display) {MatView(B,vstdout);}
2609:       if (vdraw) {MatView(B,vdraw);}
2610:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2611:       if (flag_display) {MatView(Bfd,vstdout);}
2612:       if (vdraw) {MatView(Bfd,vdraw);}
2613:       MatAYPX(Bfd,-1.0,B,SAME_NONZERO_PATTERN);
2614:       MatNorm(Bfd,NORM_1,&norm1);
2615:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2616:       MatNorm(Bfd,NORM_MAX,&normmax);
2617:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2618:       if (flag_display) {MatView(Bfd,vstdout);}
2619:       if (vdraw) {              /* Always use contour for the difference */
2620:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2621:         MatView(Bfd,vdraw);
2622:         PetscViewerPopFormat(vdraw);
2623:       }
2624:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2626:       if (flag_threshold) {
2627:         PetscInt bs,rstart,rend,i;
2628:         MatGetBlockSize(B,&bs);
2629:         MatGetOwnershipRange(B,&rstart,&rend);
2630:         for (i=rstart; i<rend; i++) {
2631:           const PetscScalar *ba,*ca;
2632:           const PetscInt    *bj,*cj;
2633:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2634:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2635:           MatGetRow(B,i,&bn,&bj,&ba);
2636:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2637:           if (bn != cn) SETERRQ(((PetscObject)A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2638:           for (j=0; j<bn; j++) {
2639:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2640:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2641:               maxentrycol = bj[j];
2642:               maxentry    = PetscRealPart(ba[j]);
2643:             }
2644:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2645:               maxdiffcol = bj[j];
2646:               maxdiff    = PetscRealPart(ca[j]);
2647:             }
2648:             if (rdiff > maxrdiff) {
2649:               maxrdiffcol = bj[j];
2650:               maxrdiff    = rdiff;
2651:             }
2652:           }
2653:           if (maxrdiff > 1) {
2654:             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);
2655:             for (j=0; j<bn; j++) {
2656:               PetscReal rdiff;
2657:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2658:               if (rdiff > 1) {
2659:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2660:               }
2661:             }
2662:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2663:           }
2664:           MatRestoreRow(B,i,&bn,&bj,&ba);
2665:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2666:         }
2667:       }
2668:       PetscViewerDestroy(&vdraw);
2669:       MatDestroy(&Bfd);
2670:     }
2671:   }
2672:   return(0);
2673: }

2675: /*MC
2676:     SNESJacobianFunction - Function used to convey the nonlinear Jacobian of the function to be solved by SNES

2678:      Synopsis:
2679:      #include "petscsnes.h"
2680:      PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);

2682: +  x - input vector
2683: .  Amat - the matrix that defines the (approximate) Jacobian
2684: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2685: -  ctx - [optional] user-defined Jacobian context

2687:    Level: intermediate

2689: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2690: M*/

2692: /*@C
2693:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2694:    location to store the matrix.

2696:    Logically Collective on SNES and Mat

2698:    Input Parameters:
2699: +  snes - the SNES context
2700: .  Amat - the matrix that defines the (approximate) Jacobian
2701: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2702: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value), see SNESJacobianFunction for details
2703: -  ctx - [optional] user-defined context for private data for the
2704:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2706:    Notes:
2707:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2708:    each matrix.

2710:    If you know the operator Amat has a null space you can use MatSetNullSpace() and MatSetTransposeNullSpace() to supply the null
2711:    space to Amat and the KSP solvers will automatically use that null space as needed during the solution process.

2713:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2714:    must be a MatFDColoring.

2716:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2717:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2719:    Level: beginner

2721: .keywords: SNES, nonlinear, set, Jacobian, matrix

2723: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J,
2724:           SNESSetPicard(), SNESJacobianFunction
2725: @*/
2726: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2727: {
2729:   DM             dm;

2737:   SNESGetDM(snes,&dm);
2738:   DMSNESSetJacobian(dm,J,ctx);
2739:   if (Amat) {
2740:     PetscObjectReference((PetscObject)Amat);
2741:     MatDestroy(&snes->jacobian);

2743:     snes->jacobian = Amat;
2744:   }
2745:   if (Pmat) {
2746:     PetscObjectReference((PetscObject)Pmat);
2747:     MatDestroy(&snes->jacobian_pre);

2749:     snes->jacobian_pre = Pmat;
2750:   }
2751:   return(0);
2752: }

2754: /*@C
2755:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2756:    provided context for evaluating the Jacobian.

2758:    Not Collective, but Mat object will be parallel if SNES object is

2760:    Input Parameter:
2761: .  snes - the nonlinear solver context

2763:    Output Parameters:
2764: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
2765: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
2766: .  J - location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
2767: -  ctx - location to stash Jacobian ctx (or NULL)

2769:    Level: advanced

2771: .seealso: SNESSetJacobian(), SNESComputeJacobian(), SNESJacobianFunction, SNESGetFunction()
2772: @*/
2773: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
2774: {
2776:   DM             dm;
2777:   DMSNES         sdm;

2781:   if (Amat) *Amat = snes->jacobian;
2782:   if (Pmat) *Pmat = snes->jacobian_pre;
2783:   SNESGetDM(snes,&dm);
2784:   DMGetDMSNES(dm,&sdm);
2785:   if (J) *J = sdm->ops->computejacobian;
2786:   if (ctx) *ctx = sdm->jacobianctx;
2787:   return(0);
2788: }

2790: /*@
2791:    SNESSetUp - Sets up the internal data structures for the later use
2792:    of a nonlinear solver.

2794:    Collective on SNES

2796:    Input Parameters:
2797: .  snes - the SNES context

2799:    Notes:
2800:    For basic use of the SNES solvers the user need not explicitly call
2801:    SNESSetUp(), since these actions will automatically occur during
2802:    the call to SNESSolve().  However, if one wishes to control this
2803:    phase separately, SNESSetUp() should be called after SNESCreate()
2804:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

2806:    Level: advanced

2808: .keywords: SNES, nonlinear, setup

2810: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
2811: @*/
2812: PetscErrorCode  SNESSetUp(SNES snes)
2813: {
2815:   DM             dm;
2816:   DMSNES         sdm;
2817:   SNESLineSearch linesearch, pclinesearch;
2818:   void           *lsprectx,*lspostctx;
2819:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
2820:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
2821:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2822:   Vec            f,fpc;
2823:   void           *funcctx;
2824:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
2825:   void           *jacctx,*appctx;
2826:   Mat            j,jpre;

2830:   if (snes->setupcalled) return(0);

2832:   if (!((PetscObject)snes)->type_name) {
2833:     SNESSetType(snes,SNESNEWTONLS);
2834:   }

2836:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

2838:   SNESGetDM(snes,&dm);
2839:   DMGetDMSNES(dm,&sdm);
2840:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
2841:   if (!sdm->ops->computejacobian) {
2842:     DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
2843:   }
2844:   if (!snes->vec_func) {
2845:     DMCreateGlobalVector(dm,&snes->vec_func);
2846:   }

2848:   if (!snes->ksp) {
2849:     SNESGetKSP(snes, &snes->ksp);
2850:   }

2852:   if (!snes->linesearch) {
2853:     SNESGetLineSearch(snes, &snes->linesearch);
2854:   }
2855:   SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);

2857:   if (snes->npc && (snes->npcside== PC_LEFT)) {
2858:     snes->mf          = PETSC_TRUE;
2859:     snes->mf_operator = PETSC_FALSE;
2860:   }

2862:   if (snes->npc) {
2863:     /* copy the DM over */
2864:     SNESGetDM(snes,&dm);
2865:     SNESSetDM(snes->npc,dm);

2867:     SNESGetFunction(snes,&f,&func,&funcctx);
2868:     VecDuplicate(f,&fpc);
2869:     SNESSetFunction(snes->npc,fpc,func,funcctx);
2870:     SNESGetJacobian(snes,&j,&jpre,&jac,&jacctx);
2871:     SNESSetJacobian(snes->npc,j,jpre,jac,jacctx);
2872:     SNESGetApplicationContext(snes,&appctx);
2873:     SNESSetApplicationContext(snes->npc,appctx);
2874:     VecDestroy(&fpc);

2876:     /* copy the function pointers over */
2877:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->npc);

2879:     /* default to 1 iteration */
2880:     SNESSetTolerances(snes->npc,0.0,0.0,0.0,1,snes->npc->max_funcs);
2881:     if (snes->npcside==PC_RIGHT) {
2882:       SNESSetNormSchedule(snes->npc,SNES_NORM_FINAL_ONLY);
2883:     } else {
2884:       SNESSetNormSchedule(snes->npc,SNES_NORM_NONE);
2885:     }
2886:     SNESSetFromOptions(snes->npc);

2888:     /* copy the line search context over */
2889:     SNESGetLineSearch(snes,&linesearch);
2890:     SNESGetLineSearch(snes->npc,&pclinesearch);
2891:     SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
2892:     SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
2893:     SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
2894:     SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
2895:     PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
2896:   }
2897:   if (snes->mf) {
2898:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
2899:   }
2900:   if (snes->ops->usercompute && !snes->user) {
2901:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
2902:   }

2904:   snes->jac_iter = 0;
2905:   snes->pre_iter = 0;

2907:   if (snes->ops->setup) {
2908:     (*snes->ops->setup)(snes);
2909:   }

2911:   if (snes->npc && (snes->npcside== PC_LEFT)) {
2912:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
2913:       SNESGetLineSearch(snes,&linesearch);
2914:       SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultNPC);
2915:     }
2916:   }

2918:   snes->setupcalled = PETSC_TRUE;
2919:   return(0);
2920: }

2922: /*@
2923:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

2925:    Collective on SNES

2927:    Input Parameter:
2928: .  snes - iterative context obtained from SNESCreate()

2930:    Level: intermediate

2932:    Notes: Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

2934: .keywords: SNES, destroy

2936: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
2937: @*/
2938: PetscErrorCode  SNESReset(SNES snes)
2939: {

2944:   if (snes->ops->userdestroy && snes->user) {
2945:     (*snes->ops->userdestroy)((void**)&snes->user);
2946:     snes->user = NULL;
2947:   }
2948:   if (snes->npc) {
2949:     SNESReset(snes->npc);
2950:   }

2952:   if (snes->ops->reset) {
2953:     (*snes->ops->reset)(snes);
2954:   }
2955:   if (snes->ksp) {
2956:     KSPReset(snes->ksp);
2957:   }

2959:   if (snes->linesearch) {
2960:     SNESLineSearchReset(snes->linesearch);
2961:   }

2963:   VecDestroy(&snes->vec_rhs);
2964:   VecDestroy(&snes->vec_sol);
2965:   VecDestroy(&snes->vec_sol_update);
2966:   VecDestroy(&snes->vec_func);
2967:   MatDestroy(&snes->jacobian);
2968:   MatDestroy(&snes->jacobian_pre);
2969:   VecDestroyVecs(snes->nwork,&snes->work);
2970:   VecDestroyVecs(snes->nvwork,&snes->vwork);

2972:   snes->alwayscomputesfinalresidual = PETSC_FALSE;

2974:   snes->nwork       = snes->nvwork = 0;
2975:   snes->setupcalled = PETSC_FALSE;
2976:   return(0);
2977: }

2979: /*@
2980:    SNESDestroy - Destroys the nonlinear solver context that was created
2981:    with SNESCreate().

2983:    Collective on SNES

2985:    Input Parameter:
2986: .  snes - the SNES context

2988:    Level: beginner

2990: .keywords: SNES, nonlinear, destroy

2992: .seealso: SNESCreate(), SNESSolve()
2993: @*/
2994: PetscErrorCode  SNESDestroy(SNES *snes)
2995: {

2999:   if (!*snes) return(0);
3001:   if (--((PetscObject)(*snes))->refct > 0) {*snes = 0; return(0);}

3003:   SNESReset((*snes));
3004:   SNESDestroy(&(*snes)->npc);

3006:   /* if memory was published with SAWs then destroy it */
3007:   PetscObjectSAWsViewOff((PetscObject)*snes);
3008:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

3010:   if ((*snes)->dm) {DMCoarsenHookRemove((*snes)->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,*snes);}
3011:   DMDestroy(&(*snes)->dm);
3012:   KSPDestroy(&(*snes)->ksp);
3013:   SNESLineSearchDestroy(&(*snes)->linesearch);

3015:   PetscFree((*snes)->kspconvctx);
3016:   if ((*snes)->ops->convergeddestroy) {
3017:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
3018:   }
3019:   if ((*snes)->conv_malloc) {
3020:     PetscFree((*snes)->conv_hist);
3021:     PetscFree((*snes)->conv_hist_its);
3022:   }
3023:   SNESMonitorCancel((*snes));
3024:   PetscHeaderDestroy(snes);
3025:   return(0);
3026: }

3028: /* ----------- Routines to set solver parameters ---------- */

3030: /*@
3031:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

3033:    Logically Collective on SNES

3035:    Input Parameters:
3036: +  snes - the SNES context
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
3046:    If  -1 is used before the very first nonlinear solve the preconditioner is still built because there is no previous preconditioner to use

3048:    Level: intermediate

3050: .keywords: SNES, nonlinear, set, convergence, tolerances

3052: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian()

3054: @*/
3055: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
3056: {
3059:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3060:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3062:   snes->lagpreconditioner = lag;
3063:   return(0);
3064: }

3066: /*@
3067:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

3069:    Logically Collective on SNES

3071:    Input Parameters:
3072: +  snes - the SNES context
3073: -  steps - the number of refinements to do, defaults to 0

3075:    Options Database Keys:
3076: .    -snes_grid_sequence <steps>

3078:    Level: intermediate

3080:    Notes:
3081:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3083: .keywords: SNES, nonlinear, set, convergence, tolerances

3085: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetGridSequence()

3087: @*/
3088: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
3089: {
3093:   snes->gridsequence = steps;
3094:   return(0);
3095: }

3097: /*@
3098:    SNESGetGridSequence - gets the number of steps of grid sequencing that SNES does

3100:    Logically Collective on SNES

3102:    Input Parameter:
3103: .  snes - the SNES context

3105:    Output Parameter:
3106: .  steps - the number of refinements to do, defaults to 0

3108:    Options Database Keys:
3109: .    -snes_grid_sequence <steps>

3111:    Level: intermediate

3113:    Notes:
3114:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

3116: .keywords: SNES, nonlinear, set, convergence, tolerances

3118: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetGridSequence()

3120: @*/
3121: PetscErrorCode  SNESGetGridSequence(SNES snes,PetscInt *steps)
3122: {
3125:   *steps = snes->gridsequence;
3126:   return(0);
3127: }

3129: /*@
3130:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

3132:    Not Collective

3134:    Input Parameter:
3135: .  snes - the SNES context

3137:    Output Parameter:
3138: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3139:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

3141:    Options Database Keys:
3142: .    -snes_lag_preconditioner <lag>

3144:    Notes:
3145:    The default is 1
3146:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3148:    Level: intermediate

3150: .keywords: SNES, nonlinear, set, convergence, tolerances

3152: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner()

3154: @*/
3155: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
3156: {
3159:   *lag = snes->lagpreconditioner;
3160:   return(0);
3161: }

3163: /*@
3164:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
3165:      often the preconditioner is rebuilt.

3167:    Logically Collective on SNES

3169:    Input Parameters:
3170: +  snes - the SNES context
3171: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3172:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

3174:    Options Database Keys:
3175: .    -snes_lag_jacobian <lag>

3177:    Notes:
3178:    The default is 1
3179:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
3180:    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
3181:    at the next Newton step but never again (unless it is reset to another value)

3183:    Level: intermediate

3185: .keywords: SNES, nonlinear, set, convergence, tolerances

3187: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobian()

3189: @*/
3190: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
3191: {
3194:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
3195:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
3197:   snes->lagjacobian = lag;
3198:   return(0);
3199: }

3201: /*@
3202:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

3204:    Not Collective

3206:    Input Parameter:
3207: .  snes - the SNES context

3209:    Output Parameter:
3210: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
3211:          the Jacobian is built etc.

3213:    Options Database Keys:
3214: .    -snes_lag_jacobian <lag>

3216:    Notes:
3217:    The default is 1
3218:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

3220:    Level: intermediate

3222: .keywords: SNES, nonlinear, set, convergence, tolerances

3224: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner()

3226: @*/
3227: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
3228: {
3231:   *lag = snes->lagjacobian;
3232:   return(0);
3233: }

3235: /*@
3236:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

3238:    Logically collective on SNES

3240:    Input Parameter:
3241: +  snes - the SNES context
3242: -   flg - jacobian lagging persists if true

3244:    Options Database Keys:
3245: .    -snes_lag_jacobian_persists <flg>

3247:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3248:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3249:    timesteps may present huge efficiency gains.

3251:    Level: developer

3253: .keywords: SNES, nonlinear, lag

3255: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3257: @*/
3258: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3259: {
3263:   snes->lagjac_persist = flg;
3264:   return(0);
3265: }

3267: /*@
3268:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple solves

3270:    Logically Collective on SNES

3272:    Input Parameter:
3273: +  snes - the SNES context
3274: -   flg - preconditioner lagging persists if true

3276:    Options Database Keys:
3277: .    -snes_lag_jacobian_persists <flg>

3279:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3280:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3281:    several timesteps may present huge efficiency gains.

3283:    Level: developer

3285: .keywords: SNES, nonlinear, lag

3287: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3289: @*/
3290: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3291: {
3295:   snes->lagpre_persist = flg;
3296:   return(0);
3297: }

3299: /*@
3300:    SNESSetForceIteration - force SNESSolve() to take at least one iteration regardless of the initial residual norm

3302:    Logically Collective on SNES

3304:    Input Parameters:
3305: +  snes - the SNES context
3306: -  force - PETSC_TRUE require at least one iteration

3308:    Options Database Keys:
3309: .    -snes_force_iteration <force> - Sets forcing an iteration

3311:    Notes:
3312:    This is used sometimes with TS to prevent TS from detecting a false steady state solution

3314:    Level: intermediate

3316: .keywords: SNES, nonlinear, set, convergence, tolerances

3318: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3319: @*/
3320: PetscErrorCode  SNESSetForceIteration(SNES snes,PetscBool force)
3321: {
3324:   snes->forceiteration = force;
3325:   return(0);
3326: }

3328: /*@
3329:    SNESGetForceIteration - Whether or not to force SNESSolve() take at least one iteration regardless of the initial residual norm

3331:    Logically Collective on SNES

3333:    Input Parameters:
3334: .  snes - the SNES context

3336:    Output Parameter:
3337: .  force - PETSC_TRUE requires at least one iteration.

3339: .keywords: SNES, nonlinear, set, convergence, tolerances

3341: .seealso: SNESSetForceIteration(), SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance()
3342: @*/
3343: PetscErrorCode  SNESGetForceIteration(SNES snes,PetscBool *force)
3344: {
3347:   *force = snes->forceiteration;
3348:   return(0);
3349: }

3351: /*@
3352:    SNESSetTolerances - Sets various parameters used in convergence tests.

3354:    Logically Collective on SNES

3356:    Input Parameters:
3357: +  snes - the SNES context
3358: .  abstol - absolute convergence tolerance
3359: .  rtol - relative convergence tolerance
3360: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3361: .  maxit - maximum number of iterations
3362: -  maxf - maximum number of function evaluations

3364:    Options Database Keys:
3365: +    -snes_atol <abstol> - Sets abstol
3366: .    -snes_rtol <rtol> - Sets rtol
3367: .    -snes_stol <stol> - Sets stol
3368: .    -snes_max_it <maxit> - Sets maxit
3369: -    -snes_max_funcs <maxf> - Sets maxf

3371:    Notes:
3372:    The default maximum number of iterations is 50.
3373:    The default maximum number of function evaluations is 1000.

3375:    Level: intermediate

3377: .keywords: SNES, nonlinear, set, convergence, tolerances

3379: .seealso: SNESSetTrustRegionTolerance(), SNESSetDivergenceTolerance(), SNESSetForceIteration()
3380: @*/
3381: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3382: {

3391:   if (abstol != PETSC_DEFAULT) {
3392:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3393:     snes->abstol = abstol;
3394:   }
3395:   if (rtol != PETSC_DEFAULT) {
3396:     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);
3397:     snes->rtol = rtol;
3398:   }
3399:   if (stol != PETSC_DEFAULT) {
3400:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3401:     snes->stol = stol;
3402:   }
3403:   if (maxit != PETSC_DEFAULT) {
3404:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3405:     snes->max_its = maxit;
3406:   }
3407:   if (maxf != PETSC_DEFAULT) {
3408:     if (maxf < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be non-negative",maxf);
3409:     snes->max_funcs = maxf;
3410:   }
3411:   snes->tolerancesset = PETSC_TRUE;
3412:   return(0);
3413: }

3415: /*@
3416:    SNESSetDivergenceTolerance - Sets the divergence tolerance used for the SNES divergence test.

3418:    Logically Collective on SNES

3420:    Input Parameters:
3421: +  snes - the SNES context
3422: -  divtol - the divergence tolerance. Use -1 to deactivate the test.

3424:    Options Database Keys:
3425: +    -snes_divergence_tolerance <divtol> - Sets divtol

3427:    Notes:
3428:    The default divergence tolerance is 1e4.

3430:    Level: intermediate

3432: .keywords: SNES, nonlinear, set, divergence, tolerance

3434: .seealso: SNESSetTolerances(), SNESGetDivergenceTolerance
3435: @*/
3436: PetscErrorCode  SNESSetDivergenceTolerance(SNES snes,PetscReal divtol)
3437: {

3442:   if (divtol != PETSC_DEFAULT) {
3443:     snes->divtol = divtol;
3444:   }
3445:   else {
3446:     snes->divtol = 1.0e4;
3447:   }
3448:   return(0);
3449: }

3451: /*@
3452:    SNESGetTolerances - Gets various parameters used in convergence tests.

3454:    Not Collective

3456:    Input Parameters:
3457: +  snes - the SNES context
3458: .  atol - absolute convergence tolerance
3459: .  rtol - relative convergence tolerance
3460: .  stol -  convergence tolerance in terms of the norm
3461:            of the change in the solution between steps
3462: .  maxit - maximum number of iterations
3463: -  maxf - maximum number of function evaluations

3465:    Notes:
3466:    The user can specify NULL for any parameter that is not needed.

3468:    Level: intermediate

3470: .keywords: SNES, nonlinear, get, convergence, tolerances

3472: .seealso: SNESSetTolerances()
3473: @*/
3474: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3475: {
3478:   if (atol)  *atol  = snes->abstol;
3479:   if (rtol)  *rtol  = snes->rtol;
3480:   if (stol)  *stol  = snes->stol;
3481:   if (maxit) *maxit = snes->max_its;
3482:   if (maxf)  *maxf  = snes->max_funcs;
3483:   return(0);
3484: }

3486: /*@
3487:    SNESGetDivergenceTolerance - Gets divergence tolerance used in divergence test.

3489:    Not Collective

3491:    Input Parameters:
3492: +  snes - the SNES context
3493: -  divtol - divergence tolerance

3495:    Level: intermediate

3497: .keywords: SNES, nonlinear, get, divergence, tolerance

3499: .seealso: SNESSetDivergenceTolerance()
3500: @*/
3501: PetscErrorCode  SNESGetDivergenceTolerance(SNES snes,PetscReal *divtol)
3502: {
3505:   if (divtol) *divtol = snes->divtol;
3506:   return(0);
3507: }

3509: /*@
3510:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3512:    Logically Collective on SNES

3514:    Input Parameters:
3515: +  snes - the SNES context
3516: -  tol - tolerance

3518:    Options Database Key:
3519: .  -snes_trtol <tol> - Sets tol

3521:    Level: intermediate

3523: .keywords: SNES, nonlinear, set, trust region, tolerance

3525: .seealso: SNESSetTolerances()
3526: @*/
3527: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3528: {
3532:   snes->deltatol = tol;
3533:   return(0);
3534: }

3536: /*
3537:    Duplicate the lg monitors for SNES from KSP; for some reason with
3538:    dynamic libraries things don't work under Sun4 if we just use
3539:    macros instead of functions
3540: */
3541: PetscErrorCode  SNESMonitorLGResidualNorm(SNES snes,PetscInt it,PetscReal norm,void *ctx)
3542: {

3547:   KSPMonitorLGResidualNorm((KSP)snes,it,norm,ctx);
3548:   return(0);
3549: }

3551: PetscErrorCode  SNESMonitorLGCreate(MPI_Comm comm,const char host[],const char label[],int x,int y,int m,int n,PetscDrawLG *lgctx)
3552: {

3556:   KSPMonitorLGResidualNormCreate(comm,host,label,x,y,m,n,lgctx);
3557:   return(0);
3558: }

3560: PETSC_INTERN PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);

3562: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3563: {
3564:   PetscDrawLG      lg;
3565:   PetscErrorCode   ierr;
3566:   PetscReal        x,y,per;
3567:   PetscViewer      v = (PetscViewer)monctx;
3568:   static PetscReal prev; /* should be in the context */
3569:   PetscDraw        draw;

3573:   PetscViewerDrawGetDrawLG(v,0,&lg);
3574:   if (!n) {PetscDrawLGReset(lg);}
3575:   PetscDrawLGGetDraw(lg,&draw);
3576:   PetscDrawSetTitle(draw,"Residual norm");
3577:   x    = (PetscReal)n;
3578:   if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3579:   else y = -15.0;
3580:   PetscDrawLGAddPoint(lg,&x,&y);
3581:   if (n < 20 || !(n % 5) || snes->reason) {
3582:     PetscDrawLGDraw(lg);
3583:     PetscDrawLGSave(lg);
3584:   }

3586:   PetscViewerDrawGetDrawLG(v,1,&lg);
3587:   if (!n) {PetscDrawLGReset(lg);}
3588:   PetscDrawLGGetDraw(lg,&draw);
3589:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3590:    SNESMonitorRange_Private(snes,n,&per);
3591:   x    = (PetscReal)n;
3592:   y    = 100.0*per;
3593:   PetscDrawLGAddPoint(lg,&x,&y);
3594:   if (n < 20 || !(n % 5) || snes->reason) {
3595:     PetscDrawLGDraw(lg);
3596:     PetscDrawLGSave(lg);
3597:   }

3599:   PetscViewerDrawGetDrawLG(v,2,&lg);
3600:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3601:   PetscDrawLGGetDraw(lg,&draw);
3602:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3603:   x    = (PetscReal)n;
3604:   y    = (prev - rnorm)/prev;
3605:   PetscDrawLGAddPoint(lg,&x,&y);
3606:   if (n < 20 || !(n % 5) || snes->reason) {
3607:     PetscDrawLGDraw(lg);
3608:     PetscDrawLGSave(lg);
3609:   }

3611:   PetscViewerDrawGetDrawLG(v,3,&lg);
3612:   if (!n) {PetscDrawLGReset(lg);}
3613:   PetscDrawLGGetDraw(lg,&draw);
3614:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3615:   x    = (PetscReal)n;
3616:   y    = (prev - rnorm)/(prev*per);
3617:   if (n > 2) { /*skip initial crazy value */
3618:     PetscDrawLGAddPoint(lg,&x,&y);
3619:   }
3620:   if (n < 20 || !(n % 5) || snes->reason) {
3621:     PetscDrawLGDraw(lg);
3622:     PetscDrawLGSave(lg);
3623:   }
3624:   prev = rnorm;
3625:   return(0);
3626: }

3628: /*@
3629:    SNESMonitor - runs the user provided monitor routines, if they exist

3631:    Collective on SNES

3633:    Input Parameters:
3634: +  snes - nonlinear solver context obtained from SNESCreate()
3635: .  iter - iteration number
3636: -  rnorm - relative norm of the residual

3638:    Notes:
3639:    This routine is called by the SNES implementations.
3640:    It does not typically need to be called by the user.

3642:    Level: developer

3644: .seealso: SNESMonitorSet()
3645: @*/
3646: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3647: {
3649:   PetscInt       i,n = snes->numbermonitors;

3652:   VecLockPush(snes->vec_sol);
3653:   for (i=0; i<n; i++) {
3654:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3655:   }
3656:   VecLockPop(snes->vec_sol);
3657:   return(0);
3658: }

3660: /* ------------ Routines to set performance monitoring options ----------- */

3662: /*MC
3663:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3665:      Synopsis:
3666:      #include <petscsnes.h>
3667: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3669: +    snes - the SNES context
3670: .    its - iteration number
3671: .    norm - 2-norm function value (may be estimated)
3672: -    mctx - [optional] monitoring context

3674:    Level: advanced

3676: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3677: M*/

3679: /*@C
3680:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3681:    iteration of the nonlinear solver to display the iteration's
3682:    progress.

3684:    Logically Collective on SNES

3686:    Input Parameters:
3687: +  snes - the SNES context
3688: .  f - the monitor function, see SNESMonitorFunction for the calling sequence
3689: .  mctx - [optional] user-defined context for private data for the
3690:           monitor routine (use NULL if no context is desired)
3691: -  monitordestroy - [optional] routine that frees monitor context
3692:           (may be NULL)

3694:    Options Database Keys:
3695: +    -snes_monitor        - sets SNESMonitorDefault()
3696: .    -snes_monitor_lg_residualnorm    - sets line graph monitor,
3697:                             uses SNESMonitorLGCreate()
3698: -    -snes_monitor_cancel - cancels all monitors that have
3699:                             been hardwired into a code by
3700:                             calls to SNESMonitorSet(), but
3701:                             does not cancel those set via
3702:                             the options database.

3704:    Notes:
3705:    Several different monitoring routines may be set by calling
3706:    SNESMonitorSet() multiple times; all will be called in the
3707:    order in which they were set.

3709:    Fortran notes: Only a single monitor function can be set for each SNES object

3711:    Level: intermediate

3713: .keywords: SNES, nonlinear, set, monitor

3715: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3716: @*/
3717: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*f)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3718: {
3719:   PetscInt       i;
3721:   PetscBool      identical;

3725:   for (i=0; i<snes->numbermonitors;i++) {
3726:     PetscMonitorCompare((PetscErrorCode (*)(void))f,mctx,monitordestroy,(PetscErrorCode (*)(void))snes->monitor[i],snes->monitorcontext[i],snes->monitordestroy[i],&identical);
3727:     if (identical) return(0);
3728:   }
3729:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3730:   snes->monitor[snes->numbermonitors]          = f;
3731:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3732:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3733:   return(0);
3734: }

3736: /*@
3737:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3739:    Logically Collective on SNES

3741:    Input Parameters:
3742: .  snes - the SNES context

3744:    Options Database Key:
3745: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
3746:     into a code by calls to SNESMonitorSet(), but does not cancel those
3747:     set via the options database

3749:    Notes:
3750:    There is no way to clear one specific monitor from a SNES object.

3752:    Level: intermediate

3754: .keywords: SNES, nonlinear, set, monitor

3756: .seealso: SNESMonitorDefault(), SNESMonitorSet()
3757: @*/
3758: PetscErrorCode  SNESMonitorCancel(SNES snes)
3759: {
3761:   PetscInt       i;

3765:   for (i=0; i<snes->numbermonitors; i++) {
3766:     if (snes->monitordestroy[i]) {
3767:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
3768:     }
3769:   }
3770:   snes->numbermonitors = 0;
3771:   return(0);
3772: }

3774: /*MC
3775:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

3777:      Synopsis:
3778:      #include <petscsnes.h>
3779: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

3781: +    snes - the SNES context
3782: .    it - current iteration (0 is the first and is before any Newton step)
3783: .    cctx - [optional] convergence context
3784: .    reason - reason for convergence/divergence
3785: .    xnorm - 2-norm of current iterate
3786: .    gnorm - 2-norm of current step
3787: -    f - 2-norm of function

3789:    Level: intermediate

3791: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
3792: M*/

3794: /*@C
3795:    SNESSetConvergenceTest - Sets the function that is to be used
3796:    to test for convergence of the nonlinear iterative solution.

3798:    Logically Collective on SNES

3800:    Input Parameters:
3801: +  snes - the SNES context
3802: .  SNESConvergenceTestFunction - routine to test for convergence
3803: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
3804: -  destroy - [optional] destructor for the context (may be NULL; NULL_FUNCTION in Fortran)

3806:    Level: advanced

3808: .keywords: SNES, nonlinear, set, convergence, test

3810: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
3811: @*/
3812: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
3813: {

3818:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
3819:   if (snes->ops->convergeddestroy) {
3820:     (*snes->ops->convergeddestroy)(snes->cnvP);
3821:   }
3822:   snes->ops->converged        = SNESConvergenceTestFunction;
3823:   snes->ops->convergeddestroy = destroy;
3824:   snes->cnvP                  = cctx;
3825:   return(0);
3826: }

3828: /*@
3829:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

3831:    Not Collective

3833:    Input Parameter:
3834: .  snes - the SNES context

3836:    Output Parameter:
3837: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3838:             manual pages for the individual convergence tests for complete lists

3840:    Options Database:
3841: .   -snes_converged_reason - prints the reason to standard out

3843:    Level: intermediate

3845:    Notes: Should only be called after the call the SNESSolve() is complete, if it is called earlier it returns the value SNES__CONVERGED_ITERATING.

3847: .keywords: SNES, nonlinear, set, convergence, test

3849: .seealso: SNESSetConvergenceTest(), SNESSetConvergedReason(), SNESConvergedReason
3850: @*/
3851: PetscErrorCode SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
3852: {
3856:   *reason = snes->reason;
3857:   return(0);
3858: }

3860: /*@
3861:    SNESSetConvergedReason - Sets the reason the SNES iteration was stopped.

3863:    Not Collective

3865:    Input Parameters:
3866: +  snes - the SNES context
3867: -  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3868:             manual pages for the individual convergence tests for complete lists

3870:    Level: intermediate

3872: .keywords: SNES, nonlinear, set, convergence, test
3873: .seealso: SNESGetConvergedReason(), SNESSetConvergenceTest(), SNESConvergedReason
3874: @*/
3875: PetscErrorCode SNESSetConvergedReason(SNES snes,SNESConvergedReason reason)
3876: {
3879:   snes->reason = reason;
3880:   return(0);
3881: }

3883: /*@
3884:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

3886:    Logically Collective on SNES

3888:    Input Parameters:
3889: +  snes - iterative context obtained from SNESCreate()
3890: .  a   - array to hold history, this array will contain the function norms computed at each step
3891: .  its - integer array holds the number of linear iterations for each solve.
3892: .  na  - size of a and its
3893: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
3894:            else it continues storing new values for new nonlinear solves after the old ones

3896:    Notes:
3897:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
3898:    default array of length 10000 is allocated.

3900:    This routine is useful, e.g., when running a code for purposes
3901:    of accurate performance monitoring, when no I/O should be done
3902:    during the section of code that is being timed.

3904:    Level: intermediate

3906: .keywords: SNES, set, convergence, history

3908: .seealso: SNESGetConvergenceHistory()

3910: @*/
3911: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
3912: {

3919:   if (!a) {
3920:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
3921:     PetscCalloc1(na,&a);
3922:     PetscCalloc1(na,&its);

3924:     snes->conv_malloc = PETSC_TRUE;
3925:   }
3926:   snes->conv_hist       = a;
3927:   snes->conv_hist_its   = its;
3928:   snes->conv_hist_max   = na;
3929:   snes->conv_hist_len   = 0;
3930:   snes->conv_hist_reset = reset;
3931:   return(0);
3932: }

3934: #if defined(PETSC_HAVE_MATLAB_ENGINE)
3935: #include <engine.h>   /* MATLAB include file */
3936: #include <mex.h>      /* MATLAB include file */

3938: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
3939: {
3940:   mxArray   *mat;
3941:   PetscInt  i;
3942:   PetscReal *ar;

3945:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
3946:   ar  = (PetscReal*) mxGetData(mat);
3947:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
3948:   PetscFunctionReturn(mat);
3949: }
3950: #endif

3952: /*@C
3953:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

3955:    Not Collective

3957:    Input Parameter:
3958: .  snes - iterative context obtained from SNESCreate()

3960:    Output Parameters:
3961: .  a   - array to hold history
3962: .  its - integer array holds the number of linear iterations (or
3963:          negative if not converged) for each solve.
3964: -  na  - size of a and its

3966:    Notes:
3967:     The calling sequence for this routine in Fortran is
3968: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

3970:    This routine is useful, e.g., when running a code for purposes
3971:    of accurate performance monitoring, when no I/O should be done
3972:    during the section of code that is being timed.

3974:    Level: intermediate

3976: .keywords: SNES, get, convergence, history

3978: .seealso: SNESSetConvergencHistory()

3980: @*/
3981: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
3982: {
3985:   if (a)   *a   = snes->conv_hist;
3986:   if (its) *its = snes->conv_hist_its;
3987:   if (na)  *na  = snes->conv_hist_len;
3988:   return(0);
3989: }

3991: /*@C
3992:   SNESSetUpdate - Sets the general-purpose update function called
3993:   at the beginning of every iteration of the nonlinear solve. Specifically
3994:   it is called just before the Jacobian is "evaluated".

3996:   Logically Collective on SNES

3998:   Input Parameters:
3999: . snes - The nonlinear solver context
4000: . func - The function

4002:   Calling sequence of func:
4003: . func (SNES snes, PetscInt step);

4005: . step - The current step of the iteration

4007:   Level: advanced

4009:   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()
4010:         This is not used by most users.

4012: .keywords: SNES, update

4014: .seealso SNESSetJacobian(), SNESSolve()
4015: @*/
4016: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
4017: {
4020:   snes->ops->update = func;
4021:   return(0);
4022: }

4024: /*
4025:    SNESScaleStep_Private - Scales a step so that its length is less than the
4026:    positive parameter delta.

4028:     Input Parameters:
4029: +   snes - the SNES context
4030: .   y - approximate solution of linear system
4031: .   fnorm - 2-norm of current function
4032: -   delta - trust region size

4034:     Output Parameters:
4035: +   gpnorm - predicted function norm at the new point, assuming local
4036:     linearization.  The value is zero if the step lies within the trust
4037:     region, and exceeds zero otherwise.
4038: -   ynorm - 2-norm of the step

4040:     Note:
4041:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
4042:     is set to be the maximum allowable step size.

4044: .keywords: SNES, nonlinear, scale, step
4045: */
4046: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
4047: {
4048:   PetscReal      nrm;
4049:   PetscScalar    cnorm;


4057:   VecNorm(y,NORM_2,&nrm);
4058:   if (nrm > *delta) {
4059:     nrm     = *delta/nrm;
4060:     *gpnorm = (1.0 - nrm)*(*fnorm);
4061:     cnorm   = nrm;
4062:     VecScale(y,cnorm);
4063:     *ynorm  = *delta;
4064:   } else {
4065:     *gpnorm = 0.0;
4066:     *ynorm  = nrm;
4067:   }
4068:   return(0);
4069: }

4071: /*@
4072:    SNESReasonView - Displays the reason a SNES solve converged or diverged to a viewer

4074:    Collective on SNES

4076:    Parameter:
4077: +  snes - iterative context obtained from SNESCreate()
4078: -  viewer - the viewer to display the reason


4081:    Options Database Keys:
4082: .  -snes_converged_reason - print reason for converged or diverged, also prints number of iterations

4084:    Level: beginner

4086: .keywords: SNES, solve, linear system

4088: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault()

4090: @*/
4091: PetscErrorCode  SNESReasonView(SNES snes,PetscViewer viewer)
4092: {
4093:   PetscViewerFormat format;
4094:   PetscBool         isAscii;
4095:   PetscErrorCode    ierr;

4098:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isAscii);
4099:   if (isAscii) {
4100:     PetscViewerGetFormat(viewer, &format);
4101:     PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);
4102:     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
4103:       DM                dm;
4104:       Vec               u;
4105:       PetscDS           prob;
4106:       PetscInt          Nf, f;
4107:       PetscErrorCode (**exactFuncs)(PetscInt, PetscReal, const PetscReal[], PetscInt, PetscScalar[], void *);
4108:       PetscReal         error;

4110:       SNESGetDM(snes, &dm);
4111:       SNESGetSolution(snes, &u);
4112:       DMGetDS(dm, &prob);
4113:       PetscDSGetNumFields(prob, &Nf);
4114:       PetscMalloc1(Nf, &exactFuncs);
4115:       for (f = 0; f < Nf; ++f) {PetscDSGetExactSolution(prob, f, &exactFuncs[f]);}
4116:       DMComputeL2Diff(dm, 0.0, exactFuncs, NULL, u, &error);
4117:       PetscFree(exactFuncs);
4118:       if (error < 1.0e-11) {PetscViewerASCIIPrintf(viewer, "L_2 Error: < 1.0e-11\n");}
4119:       else                 {PetscViewerASCIIPrintf(viewer, "L_2 Error: %g\n", error);}
4120:     }
4121:     if (snes->reason > 0) {
4122:       if (((PetscObject) snes)->prefix) {
4123:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve converged due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4124:       } else {
4125:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4126:       }
4127:     } else {
4128:       if (((PetscObject) snes)->prefix) {
4129:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve did not converge due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
4130:       } else {
4131:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
4132:       }
4133:     }
4134:     PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);
4135:   }
4136:   return(0);
4137: }

4139: /*@C
4140:   SNESReasonViewFromOptions - Processes command line options to determine if/how a SNESReason is to be viewed.

4142:   Collective on SNES

4144:   Input Parameters:
4145: . snes   - the SNES object

4147:   Level: intermediate

4149: @*/
4150: PetscErrorCode SNESReasonViewFromOptions(SNES snes)
4151: {
4152:   PetscErrorCode    ierr;
4153:   PetscViewer       viewer;
4154:   PetscBool         flg;
4155:   static PetscBool  incall = PETSC_FALSE;
4156:   PetscViewerFormat format;

4159:   if (incall) return(0);
4160:   incall = PETSC_TRUE;
4161:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_converged_reason",&viewer,&format,&flg);
4162:   if (flg) {
4163:     PetscViewerPushFormat(viewer,format);
4164:     SNESReasonView(snes,viewer);
4165:     PetscViewerPopFormat(viewer);
4166:     PetscViewerDestroy(&viewer);
4167:   }
4168:   incall = PETSC_FALSE;
4169:   return(0);
4170: }

4172: /*@C
4173:    SNESSolve - Solves a nonlinear system F(x) = b.
4174:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

4176:    Collective on SNES

4178:    Input Parameters:
4179: +  snes - the SNES context
4180: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
4181: -  x - the solution vector.

4183:    Notes:
4184:    The user should initialize the vector,x, with the initial guess
4185:    for the nonlinear solve prior to calling SNESSolve.  In particular,
4186:    to employ an initial guess of zero, the user should explicitly set
4187:    this vector to zero by calling VecSet().

4189:    Level: beginner

4191: .keywords: SNES, nonlinear, solve

4193: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
4194: @*/
4195: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
4196: {
4197:   PetscErrorCode    ierr;
4198:   PetscBool         flg;
4199:   PetscInt          grid;
4200:   Vec               xcreated = NULL;
4201:   DM                dm;


4210:   /* High level operations using the nonlinear solver */
4211:   {
4212:     PetscViewer       viewer;
4213:     PetscViewerFormat format;
4214:     PetscInt          num;
4215:     PetscBool         flg;
4216:     static PetscBool  incall = PETSC_FALSE;

4218:     if (!incall) {
4219:       /* Estimate the convergence rate of the discretization */
4220:       PetscOptionsGetViewer(PetscObjectComm((PetscObject) snes), ((PetscObject) snes)->prefix, "-snes_convergence_estimate", &viewer, &format, &flg);
4221:       if (flg) {
4222:         PetscConvEst conv;
4223:         PetscReal    alpha; /* Convergence rate of the solution error in the L_2 norm */

4225:         incall = PETSC_TRUE;
4226:         PetscConvEstCreate(PetscObjectComm((PetscObject) snes), &conv);
4227:         PetscConvEstSetSolver(conv, snes);
4228:         PetscConvEstSetFromOptions(conv);
4229:         PetscConvEstSetUp(conv);
4230:         PetscConvEstGetConvRate(conv, &alpha);
4231:         PetscViewerPushFormat(viewer, format);
4232:         PetscConvEstRateView(conv, alpha, viewer);
4233:         PetscViewerPopFormat(viewer);
4234:         PetscViewerDestroy(&viewer);
4235:         PetscConvEstDestroy(&conv);
4236:         incall = PETSC_FALSE;
4237:       }
4238:       /* Adaptively refine the initial grid */
4239:       num  = 1;
4240:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_initial", &num, &flg);
4241:       if (flg) {
4242:         DMAdaptor adaptor;

4244:         incall = PETSC_TRUE;
4245:         DMAdaptorCreate(PETSC_COMM_WORLD, &adaptor);
4246:         DMAdaptorSetSolver(adaptor, snes);
4247:         DMAdaptorSetSequenceLength(adaptor, num);
4248:         DMAdaptorSetFromOptions(adaptor);
4249:         DMAdaptorSetUp(adaptor);
4250:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_INITIAL, &dm, &x);
4251:         DMAdaptorDestroy(&adaptor);
4252:         incall = PETSC_FALSE;
4253:       }
4254:       /* Use grid sequencing to adapt */
4255:       num  = 0;
4256:       PetscOptionsGetInt(NULL, ((PetscObject) snes)->prefix, "-snes_adapt_sequence", &num, NULL);
4257:       if (num) {
4258:         DMAdaptor adaptor;

4260:         incall = PETSC_TRUE;
4261:         DMAdaptorCreate(PETSC_COMM_WORLD, &adaptor);
4262:         DMAdaptorSetSolver(adaptor, snes);
4263:         DMAdaptorSetSequenceLength(adaptor, num);
4264:         DMAdaptorSetFromOptions(adaptor);
4265:         DMAdaptorSetUp(adaptor);
4266:         DMAdaptorAdapt(adaptor, x, DM_ADAPTATION_SEQUENTIAL, &dm, &x);
4267:         DMAdaptorDestroy(&adaptor);
4268:         incall = PETSC_FALSE;
4269:       }
4270:     }
4271:   }
4272:   if (!x) {
4273:     SNESGetDM(snes,&dm);
4274:     DMCreateGlobalVector(dm,&xcreated);
4275:     x    = xcreated;
4276:   }
4277:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

4279:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
4280:   for (grid=0; grid<snes->gridsequence+1; grid++) {

4282:     /* set solution vector */
4283:     if (!grid) {PetscObjectReference((PetscObject)x);}
4284:     VecDestroy(&snes->vec_sol);
4285:     snes->vec_sol = x;
4286:     SNESGetDM(snes,&dm);

4288:     /* set affine vector if provided */
4289:     if (b) { PetscObjectReference((PetscObject)b); }
4290:     VecDestroy(&snes->vec_rhs);
4291:     snes->vec_rhs = b;

4293:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
4294:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
4295:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
4296:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
4297:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
4298:     }
4299:     DMShellSetGlobalVector(dm,snes->vec_sol);
4300:     SNESSetUp(snes);

4302:     if (!grid) {
4303:       if (snes->ops->computeinitialguess) {
4304:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
4305:       }
4306:     }

4308:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
4309:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

4311:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
4312:     (*snes->ops->solve)(snes);
4313:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
4314:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");
4315:     snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */

4317:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
4318:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

4320:     PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_test_local_min",NULL,NULL,&flg);
4321:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
4322:     SNESReasonViewFromOptions(snes);

4324:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
4325:     if (snes->reason < 0) break;
4326:     if (grid <  snes->gridsequence) {
4327:       DM  fine;
4328:       Vec xnew;
4329:       Mat interp;

4331:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
4332:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
4333:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
4334:       DMCreateGlobalVector(fine,&xnew);
4335:       MatInterpolate(interp,x,xnew);
4336:       DMInterpolate(snes->dm,interp,fine);
4337:       MatDestroy(&interp);
4338:       x    = xnew;

4340:       SNESReset(snes);
4341:       SNESSetDM(snes,fine);
4342:       DMDestroy(&fine);
4343:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
4344:     }
4345:   }
4346:   SNESViewFromOptions(snes,NULL,"-snes_view");
4347:   VecViewFromOptions(snes->vec_sol,(PetscObject)snes,"-snes_view_solution");

4349:   VecDestroy(&xcreated);
4350:   PetscObjectSAWsBlock((PetscObject)snes);
4351:   return(0);
4352: }

4354: /* --------- Internal routines for SNES Package --------- */

4356: /*@C
4357:    SNESSetType - Sets the method for the nonlinear solver.

4359:    Collective on SNES

4361:    Input Parameters:
4362: +  snes - the SNES context
4363: -  type - a known method

4365:    Options Database Key:
4366: .  -snes_type <type> - Sets the method; use -help for a list
4367:    of available methods (for instance, newtonls or newtontr)

4369:    Notes:
4370:    See "petsc/include/petscsnes.h" for available methods (for instance)
4371: +    SNESNEWTONLS - Newton's method with line search
4372:      (systems of nonlinear equations)
4373: .    SNESNEWTONTR - Newton's method with trust region
4374:      (systems of nonlinear equations)

4376:   Normally, it is best to use the SNESSetFromOptions() command and then
4377:   set the SNES solver type from the options database rather than by using
4378:   this routine.  Using the options database provides the user with
4379:   maximum flexibility in evaluating the many nonlinear solvers.
4380:   The SNESSetType() routine is provided for those situations where it
4381:   is necessary to set the nonlinear solver independently of the command
4382:   line or options database.  This might be the case, for example, when
4383:   the choice of solver changes during the execution of the program,
4384:   and the user's application is taking responsibility for choosing the
4385:   appropriate method.

4387:     Developer Notes: SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
4388:     the constructor in that list and calls it to create the spexific object.

4390:   Level: intermediate

4392: .keywords: SNES, set, type

4394: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

4396: @*/
4397: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
4398: {
4399:   PetscErrorCode ierr,(*r)(SNES);
4400:   PetscBool      match;


4406:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
4407:   if (match) return(0);

4409:    PetscFunctionListFind(SNESList,type,&r);
4410:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
4411:   /* Destroy the previous private SNES context */
4412:   if (snes->ops->destroy) {
4413:     (*(snes)->ops->destroy)(snes);
4414:     snes->ops->destroy = NULL;
4415:   }
4416:   /* Reinitialize function pointers in SNESOps structure */
4417:   snes->ops->setup          = 0;
4418:   snes->ops->solve          = 0;
4419:   snes->ops->view           = 0;
4420:   snes->ops->setfromoptions = 0;
4421:   snes->ops->destroy        = 0;
4422:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4423:   snes->setupcalled = PETSC_FALSE;

4425:   PetscObjectChangeTypeName((PetscObject)snes,type);
4426:   (*r)(snes);
4427:   return(0);
4428: }

4430: /*@C
4431:    SNESGetType - Gets the SNES method type and name (as a string).

4433:    Not Collective

4435:    Input Parameter:
4436: .  snes - nonlinear solver context

4438:    Output Parameter:
4439: .  type - SNES method (a character string)

4441:    Level: intermediate

4443: .keywords: SNES, nonlinear, get, type, name
4444: @*/
4445: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
4446: {
4450:   *type = ((PetscObject)snes)->type_name;
4451:   return(0);
4452: }

4454: /*@
4455:   SNESSetSolution - Sets the solution vector for use by the SNES routines.

4457:   Logically Collective on SNES and Vec

4459:   Input Parameters:
4460: + snes - the SNES context obtained from SNESCreate()
4461: - u    - the solution vector

4463:   Level: beginner

4465: .keywords: SNES, set, solution
4466: @*/
4467: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4468: {
4469:   DM             dm;

4475:   PetscObjectReference((PetscObject) u);
4476:   VecDestroy(&snes->vec_sol);

4478:   snes->vec_sol = u;

4480:   SNESGetDM(snes, &dm);
4481:   DMShellSetGlobalVector(dm, u);
4482:   return(0);
4483: }

4485: /*@
4486:    SNESGetSolution - Returns the vector where the approximate solution is
4487:    stored. This is the fine grid solution when using SNESSetGridSequence().

4489:    Not Collective, but Vec is parallel if SNES is parallel

4491:    Input Parameter:
4492: .  snes - the SNES context

4494:    Output Parameter:
4495: .  x - the solution

4497:    Level: intermediate

4499: .keywords: SNES, nonlinear, get, solution

4501: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
4502: @*/
4503: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
4504: {
4508:   *x = snes->vec_sol;
4509:   return(0);
4510: }

4512: /*@
4513:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4514:    stored.

4516:    Not Collective, but Vec is parallel if SNES is parallel

4518:    Input Parameter:
4519: .  snes - the SNES context

4521:    Output Parameter:
4522: .  x - the solution update

4524:    Level: advanced

4526: .keywords: SNES, nonlinear, get, solution, update

4528: .seealso: SNESGetSolution(), SNESGetFunction()
4529: @*/
4530: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4531: {
4535:   *x = snes->vec_sol_update;
4536:   return(0);
4537: }

4539: /*@C
4540:    SNESGetFunction - Returns the vector where the function is stored.

4542:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4544:    Input Parameter:
4545: .  snes - the SNES context

4547:    Output Parameter:
4548: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4549: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4550: -  ctx - the function context (or NULL if you don't want it)

4552:    Level: advanced

4554: .keywords: SNES, nonlinear, get, function

4556: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4557: @*/
4558: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4559: {
4561:   DM             dm;

4565:   if (r) {
4566:     if (!snes->vec_func) {
4567:       if (snes->vec_rhs) {
4568:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4569:       } else if (snes->vec_sol) {
4570:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4571:       } else if (snes->dm) {
4572:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4573:       }
4574:     }
4575:     *r = snes->vec_func;
4576:   }
4577:   SNESGetDM(snes,&dm);
4578:   DMSNESGetFunction(dm,f,ctx);
4579:   return(0);
4580: }

4582: /*@C
4583:    SNESGetNGS - Returns the NGS function and context.

4585:    Input Parameter:
4586: .  snes - the SNES context

4588:    Output Parameter:
4589: +  f - the function (or NULL) see SNESNGSFunction for details
4590: -  ctx    - the function context (or NULL)

4592:    Level: advanced

4594: .keywords: SNES, nonlinear, get, function

4596: .seealso: SNESSetNGS(), SNESGetFunction()
4597: @*/

4599: PetscErrorCode SNESGetNGS (SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void*), void ** ctx)
4600: {
4602:   DM             dm;

4606:   SNESGetDM(snes,&dm);
4607:   DMSNESGetNGS(dm,f,ctx);
4608:   return(0);
4609: }

4611: /*@C
4612:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4613:    SNES options in the database.

4615:    Logically Collective on SNES

4617:    Input Parameter:
4618: +  snes - the SNES context
4619: -  prefix - the prefix to prepend to all option names

4621:    Notes:
4622:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4623:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4625:    Level: advanced

4627: .keywords: SNES, set, options, prefix, database

4629: .seealso: SNESSetFromOptions()
4630: @*/
4631: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4632: {

4637:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4638:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4639:   if (snes->linesearch) {
4640:     SNESGetLineSearch(snes,&snes->linesearch);
4641:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4642:   }
4643:   KSPSetOptionsPrefix(snes->ksp,prefix);
4644:   return(0);
4645: }

4647: /*@C
4648:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4649:    SNES options in the database.

4651:    Logically Collective on SNES

4653:    Input Parameters:
4654: +  snes - the SNES context
4655: -  prefix - the prefix to prepend to all option names

4657:    Notes:
4658:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4659:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4661:    Level: advanced

4663: .keywords: SNES, append, options, prefix, database

4665: .seealso: SNESGetOptionsPrefix()
4666: @*/
4667: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
4668: {

4673:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
4674:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4675:   if (snes->linesearch) {
4676:     SNESGetLineSearch(snes,&snes->linesearch);
4677:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
4678:   }
4679:   KSPAppendOptionsPrefix(snes->ksp,prefix);
4680:   return(0);
4681: }

4683: /*@C
4684:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
4685:    SNES options in the database.

4687:    Not Collective

4689:    Input Parameter:
4690: .  snes - the SNES context

4692:    Output Parameter:
4693: .  prefix - pointer to the prefix string used

4695:    Notes: On the fortran side, the user should pass in a string 'prefix' of
4696:    sufficient length to hold the prefix.

4698:    Level: advanced

4700: .keywords: SNES, get, options, prefix, database

4702: .seealso: SNESAppendOptionsPrefix()
4703: @*/
4704: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
4705: {

4710:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
4711:   return(0);
4712: }


4715: /*@C
4716:   SNESRegister - Adds a method to the nonlinear solver package.

4718:    Not collective

4720:    Input Parameters:
4721: +  name_solver - name of a new user-defined solver
4722: -  routine_create - routine to create method context

4724:    Notes:
4725:    SNESRegister() may be called multiple times to add several user-defined solvers.

4727:    Sample usage:
4728: .vb
4729:    SNESRegister("my_solver",MySolverCreate);
4730: .ve

4732:    Then, your solver can be chosen with the procedural interface via
4733: $     SNESSetType(snes,"my_solver")
4734:    or at runtime via the option
4735: $     -snes_type my_solver

4737:    Level: advanced

4739:     Note: If your function is not being put into a shared library then use SNESRegister() instead

4741: .keywords: SNES, nonlinear, register

4743: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

4745:   Level: advanced
4746: @*/
4747: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
4748: {

4752:   PetscFunctionListAdd(&SNESList,sname,function);
4753:   return(0);
4754: }

4756: PetscErrorCode  SNESTestLocalMin(SNES snes)
4757: {
4759:   PetscInt       N,i,j;
4760:   Vec            u,uh,fh;
4761:   PetscScalar    value;
4762:   PetscReal      norm;

4765:   SNESGetSolution(snes,&u);
4766:   VecDuplicate(u,&uh);
4767:   VecDuplicate(u,&fh);

4769:   /* currently only works for sequential */
4770:   PetscPrintf(PETSC_COMM_WORLD,"Testing FormFunction() for local min\n");
4771:   VecGetSize(u,&N);
4772:   for (i=0; i<N; i++) {
4773:     VecCopy(u,uh);
4774:     PetscPrintf(PETSC_COMM_WORLD,"i = %D\n",i);
4775:     for (j=-10; j<11; j++) {
4776:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
4777:       VecSetValue(uh,i,value,ADD_VALUES);
4778:       SNESComputeFunction(snes,uh,fh);
4779:       VecNorm(fh,NORM_2,&norm);
4780:       PetscPrintf(PETSC_COMM_WORLD,"       j norm %D %18.16e\n",j,norm);
4781:       value = -value;
4782:       VecSetValue(uh,i,value,ADD_VALUES);
4783:     }
4784:   }
4785:   VecDestroy(&uh);
4786:   VecDestroy(&fh);
4787:   return(0);
4788: }

4790: /*@
4791:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
4792:    computing relative tolerance for linear solvers within an inexact
4793:    Newton method.

4795:    Logically Collective on SNES

4797:    Input Parameters:
4798: +  snes - SNES context
4799: -  flag - PETSC_TRUE or PETSC_FALSE

4801:     Options Database:
4802: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
4803: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
4804: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
4805: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
4806: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
4807: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
4808: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
4809: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

4811:    Notes:
4812:    Currently, the default is to use a constant relative tolerance for
4813:    the inner linear solvers.  Alternatively, one can use the
4814:    Eisenstat-Walker method, where the relative convergence tolerance
4815:    is reset at each Newton iteration according progress of the nonlinear
4816:    solver.

4818:    Level: advanced

4820:    Reference:
4821:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4822:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4824: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4826: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4827: @*/
4828: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
4829: {
4833:   snes->ksp_ewconv = flag;
4834:   return(0);
4835: }

4837: /*@
4838:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
4839:    for computing relative tolerance for linear solvers within an
4840:    inexact Newton method.

4842:    Not Collective

4844:    Input Parameter:
4845: .  snes - SNES context

4847:    Output Parameter:
4848: .  flag - PETSC_TRUE or PETSC_FALSE

4850:    Notes:
4851:    Currently, the default is to use a constant relative tolerance for
4852:    the inner linear solvers.  Alternatively, one can use the
4853:    Eisenstat-Walker method, where the relative convergence tolerance
4854:    is reset at each Newton iteration according progress of the nonlinear
4855:    solver.

4857:    Level: advanced

4859:    Reference:
4860:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4861:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4863: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4865: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4866: @*/
4867: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
4868: {
4872:   *flag = snes->ksp_ewconv;
4873:   return(0);
4874: }

4876: /*@
4877:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
4878:    convergence criteria for the linear solvers within an inexact
4879:    Newton method.

4881:    Logically Collective on SNES

4883:    Input Parameters:
4884: +    snes - SNES context
4885: .    version - version 1, 2 (default is 2) or 3
4886: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4887: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4888: .    gamma - multiplicative factor for version 2 rtol computation
4889:              (0 <= gamma2 <= 1)
4890: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4891: .    alpha2 - power for safeguard
4892: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4894:    Note:
4895:    Version 3 was contributed by Luis Chacon, June 2006.

4897:    Use PETSC_DEFAULT to retain the default for any of the parameters.

4899:    Level: advanced

4901:    Reference:
4902:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4903:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
4904:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

4906: .keywords: SNES, KSP, Eisenstat, Walker, set, parameters

4908: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
4909: @*/
4910: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
4911: {
4912:   SNESKSPEW *kctx;

4916:   kctx = (SNESKSPEW*)snes->kspconvctx;
4917:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

4926:   if (version != PETSC_DEFAULT)   kctx->version   = version;
4927:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
4928:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
4929:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
4930:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
4931:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
4932:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

4934:   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);
4935:   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);
4936:   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);
4937:   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);
4938:   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);
4939:   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);
4940:   return(0);
4941: }

4943: /*@
4944:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
4945:    convergence criteria for the linear solvers within an inexact
4946:    Newton method.

4948:    Not Collective

4950:    Input Parameters:
4951:      snes - SNES context

4953:    Output Parameters:
4954: +    version - version 1, 2 (default is 2) or 3
4955: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4956: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4957: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
4958: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4959: .    alpha2 - power for safeguard
4960: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4962:    Level: advanced

4964: .keywords: SNES, KSP, Eisenstat, Walker, get, parameters

4966: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
4967: @*/
4968: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
4969: {
4970:   SNESKSPEW *kctx;

4974:   kctx = (SNESKSPEW*)snes->kspconvctx;
4975:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
4976:   if (version)   *version   = kctx->version;
4977:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
4978:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
4979:   if (gamma)     *gamma     = kctx->gamma;
4980:   if (alpha)     *alpha     = kctx->alpha;
4981:   if (alpha2)    *alpha2    = kctx->alpha2;
4982:   if (threshold) *threshold = kctx->threshold;
4983:   return(0);
4984: }

4986:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
4987: {
4989:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
4990:   PetscReal      rtol  = PETSC_DEFAULT,stol;

4993:   if (!snes->ksp_ewconv) return(0);
4994:   if (!snes->iter) {
4995:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
4996:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
4997:   }
4998:   else {
4999:     if (kctx->version == 1) {
5000:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
5001:       if (rtol < 0.0) rtol = -rtol;
5002:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
5003:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5004:     } else if (kctx->version == 2) {
5005:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5006:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
5007:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
5008:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
5009:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
5010:       /* safeguard: avoid sharp decrease of rtol */
5011:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
5012:       stol = PetscMax(rtol,stol);
5013:       rtol = PetscMin(kctx->rtol_0,stol);
5014:       /* safeguard: avoid oversolving */
5015:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
5016:       stol = PetscMax(rtol,stol);
5017:       rtol = PetscMin(kctx->rtol_0,stol);
5018:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
5019:   }
5020:   /* safeguard: avoid rtol greater than one */
5021:   rtol = PetscMin(rtol,kctx->rtol_max);
5022:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
5023:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
5024:   return(0);
5025: }

5027: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
5028: {
5030:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
5031:   PCSide         pcside;
5032:   Vec            lres;

5035:   if (!snes->ksp_ewconv) return(0);
5036:   KSPGetTolerances(ksp,&kctx->rtol_last,0,0,0);
5037:   kctx->norm_last = snes->norm;
5038:   if (kctx->version == 1) {
5039:     PC        pc;
5040:     PetscBool isNone;

5042:     KSPGetPC(ksp, &pc);
5043:     PetscObjectTypeCompare((PetscObject) pc, PCNONE, &isNone);
5044:     KSPGetPCSide(ksp,&pcside);
5045:      if (pcside == PC_RIGHT || isNone) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
5046:       /* KSP residual is true linear residual */
5047:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
5048:     } else {
5049:       /* KSP residual is preconditioned residual */
5050:       /* compute true linear residual norm */
5051:       VecDuplicate(b,&lres);
5052:       MatMult(snes->jacobian,x,lres);
5053:       VecAYPX(lres,-1.0,b);
5054:       VecNorm(lres,NORM_2,&kctx->lresid_last);
5055:       VecDestroy(&lres);
5056:     }
5057:   }
5058:   return(0);
5059: }

5061: /*@
5062:    SNESGetKSP - Returns the KSP context for a SNES solver.

5064:    Not Collective, but if SNES object is parallel, then KSP object is parallel

5066:    Input Parameter:
5067: .  snes - the SNES context

5069:    Output Parameter:
5070: .  ksp - the KSP context

5072:    Notes:
5073:    The user can then directly manipulate the KSP context to set various
5074:    options, etc.  Likewise, the user can then extract and manipulate the
5075:    PC contexts as well.

5077:    Level: beginner

5079: .keywords: SNES, nonlinear, get, KSP, context

5081: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
5082: @*/
5083: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
5084: {


5091:   if (!snes->ksp) {
5092:     PetscBool monitor = PETSC_FALSE;

5094:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
5095:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
5096:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

5098:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
5099:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);

5101:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes",&monitor,NULL);
5102:     if (monitor) {
5103:       KSPMonitorSet(snes->ksp,KSPMonitorSNES,snes,NULL);
5104:     }
5105:     monitor = PETSC_FALSE;
5106:     PetscOptionsGetBool(((PetscObject)snes)->options,((PetscObject)snes)->prefix,"-ksp_monitor_snes_lg",&monitor,NULL);
5107:     if (monitor) {
5108:       PetscObject *objs;
5109:       KSPMonitorSNESLGResidualNormCreate(PetscObjectComm((PetscObject)snes),NULL,NULL,PETSC_DECIDE,PETSC_DECIDE,600,600,&objs);
5110:       objs[0] = (PetscObject) snes;
5111:       KSPMonitorSet(snes->ksp,(PetscErrorCode (*)(KSP,PetscInt,PetscReal,void*))KSPMonitorSNESLGResidualNorm,objs,(PetscErrorCode (*)(void**))KSPMonitorSNESLGResidualNormDestroy);
5112:     }
5113:   }
5114:   *ksp = snes->ksp;
5115:   return(0);
5116: }


5119:  #include <petsc/private/dmimpl.h>
5120: /*@
5121:    SNESSetDM - Sets the DM that may be used by some nonlinear solvers or their underlying preconditioners

5123:    Logically Collective on SNES

5125:    Input Parameters:
5126: +  snes - the nonlinear solver context
5127: -  dm - the dm, cannot be NULL

5129:    Level: intermediate

5131: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
5132: @*/
5133: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
5134: {
5136:   KSP            ksp;
5137:   DMSNES         sdm;

5142:   PetscObjectReference((PetscObject)dm);
5143:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
5144:     if (snes->dm->dmsnes && !dm->dmsnes) {
5145:       DMCopyDMSNES(snes->dm,dm);
5146:       DMGetDMSNES(snes->dm,&sdm);
5147:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
5148:     }
5149:     DMCoarsenHookRemove(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
5150:     DMDestroy(&snes->dm);
5151:   }
5152:   snes->dm     = dm;
5153:   snes->dmAuto = PETSC_FALSE;

5155:   SNESGetKSP(snes,&ksp);
5156:   KSPSetDM(ksp,dm);
5157:   KSPSetDMActive(ksp,PETSC_FALSE);
5158:   if (snes->npc) {
5159:     SNESSetDM(snes->npc, snes->dm);
5160:     SNESSetNPCSide(snes,snes->npcside);
5161:   }
5162:   return(0);
5163: }

5165: /*@
5166:    SNESGetDM - Gets the DM that may be used by some preconditioners

5168:    Not Collective but DM obtained is parallel on SNES

5170:    Input Parameter:
5171: . snes - the preconditioner context

5173:    Output Parameter:
5174: .  dm - the dm

5176:    Level: intermediate

5178: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
5179: @*/
5180: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
5181: {

5186:   if (!snes->dm) {
5187:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
5188:     snes->dmAuto = PETSC_TRUE;
5189:   }
5190:   *dm = snes->dm;
5191:   return(0);
5192: }

5194: /*@
5195:   SNESSetNPC - Sets the nonlinear preconditioner to be used.

5197:   Collective on SNES

5199:   Input Parameters:
5200: + snes - iterative context obtained from SNESCreate()
5201: - pc   - the preconditioner object

5203:   Notes:
5204:   Use SNESGetNPC() to retrieve the preconditioner context (for example,
5205:   to configure it using the API).

5207:   Level: developer

5209: .keywords: SNES, set, precondition
5210: .seealso: SNESGetNPC(), SNESHasNPC()
5211: @*/
5212: PetscErrorCode SNESSetNPC(SNES snes, SNES pc)
5213: {

5220:   PetscObjectReference((PetscObject) pc);
5221:   SNESDestroy(&snes->npc);
5222:   snes->npc = pc;
5223:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->npc);
5224:   return(0);
5225: }

5227: /*@
5228:   SNESGetNPC - Creates a nonlinear preconditioning solver (SNES) to be used to precondition the nonlinear solver.

5230:   Not Collective

5232:   Input Parameter:
5233: . snes - iterative context obtained from SNESCreate()

5235:   Output Parameter:
5236: . pc - preconditioner context

5238:   Notes: If a SNES was previously set with SNESSetNPC() then that SNES is returned.

5240:   Level: developer

5242: .keywords: SNES, get, preconditioner
5243: .seealso: SNESSetNPC(), SNESHasNPC()
5244: @*/
5245: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
5246: {
5248:   const char     *optionsprefix;

5253:   if (!snes->npc) {
5254:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->npc);
5255:     PetscObjectIncrementTabLevel((PetscObject)snes->npc,(PetscObject)snes,1);
5256:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->npc);
5257:     SNESGetOptionsPrefix(snes,&optionsprefix);
5258:     SNESSetOptionsPrefix(snes->npc,optionsprefix);
5259:     SNESAppendOptionsPrefix(snes->npc,"npc_");
5260:     SNESSetCountersReset(snes->npc,PETSC_FALSE);
5261:   }
5262:   *pc = snes->npc;
5263:   return(0);
5264: }

5266: /*@
5267:   SNESHasNPC - Returns whether a nonlinear preconditioner exists

5269:   Not Collective

5271:   Input Parameter:
5272: . snes - iterative context obtained from SNESCreate()

5274:   Output Parameter:
5275: . has_npc - whether the SNES has an NPC or not

5277:   Level: developer

5279: .keywords: SNES, has, preconditioner
5280: .seealso: SNESSetNPC(), SNESGetNPC()
5281: @*/
5282: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
5283: {
5286:   *has_npc = (PetscBool) (snes->npc ? PETSC_TRUE : PETSC_FALSE);
5287:   return(0);
5288: }

5290: /*@
5291:     SNESSetNPCSide - Sets the preconditioning side.

5293:     Logically Collective on SNES

5295:     Input Parameter:
5296: .   snes - iterative context obtained from SNESCreate()

5298:     Output Parameter:
5299: .   side - the preconditioning side, where side is one of
5300: .vb
5301:       PC_LEFT - left preconditioning
5302:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5303: .ve

5305:     Options Database Keys:
5306: .   -snes_pc_side <right,left>

5308:     Notes: SNESNRICHARDSON and SNESNCG only support left preconditioning.

5310:     Level: intermediate

5312: .keywords: SNES, set, right, left, side, preconditioner, flag

5314: .seealso: SNESGetNPCSide(), KSPSetPCSide()
5315: @*/
5316: PetscErrorCode  SNESSetNPCSide(SNES snes,PCSide side)
5317: {
5321:   snes->npcside= side;
5322:   return(0);
5323: }

5325: /*@
5326:     SNESGetNPCSide - Gets the preconditioning side.

5328:     Not Collective

5330:     Input Parameter:
5331: .   snes - iterative context obtained from SNESCreate()

5333:     Output Parameter:
5334: .   side - the preconditioning side, where side is one of
5335: .vb
5336:       PC_LEFT - left preconditioning
5337:       PC_RIGHT - right preconditioning (default for most nonlinear solvers)
5338: .ve

5340:     Level: intermediate

5342: .keywords: SNES, get, right, left, side, preconditioner, flag

5344: .seealso: SNESSetNPCSide(), KSPGetPCSide()
5345: @*/
5346: PetscErrorCode  SNESGetNPCSide(SNES snes,PCSide *side)
5347: {
5351:   *side = snes->npcside;
5352:   return(0);
5353: }

5355: /*@
5356:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

5358:   Collective on SNES

5360:   Input Parameters:
5361: + snes - iterative context obtained from SNESCreate()
5362: - linesearch   - the linesearch object

5364:   Notes:
5365:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
5366:   to configure it using the API).

5368:   Level: developer

5370: .keywords: SNES, set, linesearch
5371: .seealso: SNESGetLineSearch()
5372: @*/
5373: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5374: {

5381:   PetscObjectReference((PetscObject) linesearch);
5382:   SNESLineSearchDestroy(&snes->linesearch);

5384:   snes->linesearch = linesearch;

5386:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5387:   return(0);
5388: }

5390: /*@
5391:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
5392:   or creates a default line search instance associated with the SNES and returns it.

5394:   Not Collective

5396:   Input Parameter:
5397: . snes - iterative context obtained from SNESCreate()

5399:   Output Parameter:
5400: . linesearch - linesearch context

5402:   Level: beginner

5404: .keywords: SNES, get, linesearch
5405: .seealso: SNESSetLineSearch(), SNESLineSearchCreate()
5406: @*/
5407: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5408: {
5410:   const char     *optionsprefix;

5415:   if (!snes->linesearch) {
5416:     SNESGetOptionsPrefix(snes, &optionsprefix);
5417:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
5418:     SNESLineSearchSetSNES(snes->linesearch, snes);
5419:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
5420:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
5421:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5422:   }
5423:   *linesearch = snes->linesearch;
5424:   return(0);
5425: }

5427: #if defined(PETSC_HAVE_MATLAB_ENGINE)
5428: #include <mex.h>

5430: typedef struct {char *funcname; mxArray *ctx;} SNESMatlabContext;

5432: /*
5433:    SNESComputeFunction_Matlab - Calls the function that has been set with SNESSetFunctionMatlab().

5435:    Collective on SNES

5437:    Input Parameters:
5438: +  snes - the SNES context
5439: -  x - input vector

5441:    Output Parameter:
5442: .  y - function vector, as set by SNESSetFunction()

5444:    Notes:
5445:    SNESComputeFunction() is typically used within nonlinear solvers
5446:    implementations, so most users would not generally call this routine
5447:    themselves.

5449:    Level: developer

5451: .keywords: SNES, nonlinear, compute, function

5453: .seealso: SNESSetFunction(), SNESGetFunction()
5454: */
5455: PetscErrorCode  SNESComputeFunction_Matlab(SNES snes,Vec x,Vec y, void *ctx)
5456: {
5457:   PetscErrorCode    ierr;
5458:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5459:   int               nlhs  = 1,nrhs = 5;
5460:   mxArray           *plhs[1],*prhs[5];
5461:   long long int     lx = 0,ly = 0,ls = 0;


5470:   /* call Matlab function in ctx with arguments x and y */

5472:   PetscMemcpy(&ls,&snes,sizeof(snes));
5473:   PetscMemcpy(&lx,&x,sizeof(x));
5474:   PetscMemcpy(&ly,&y,sizeof(x));
5475:   prhs[0] = mxCreateDoubleScalar((double)ls);
5476:   prhs[1] = mxCreateDoubleScalar((double)lx);
5477:   prhs[2] = mxCreateDoubleScalar((double)ly);
5478:   prhs[3] = mxCreateString(sctx->funcname);
5479:   prhs[4] = sctx->ctx;
5480:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeFunctionInternal");
5481:   mxGetScalar(plhs[0]);
5482:   mxDestroyArray(prhs[0]);
5483:   mxDestroyArray(prhs[1]);
5484:   mxDestroyArray(prhs[2]);
5485:   mxDestroyArray(prhs[3]);
5486:   mxDestroyArray(plhs[0]);
5487:   return(0);
5488: }

5490: /*
5491:    SNESSetFunctionMatlab - Sets the function evaluation routine and function
5492:    vector for use by the SNES routines in solving systems of nonlinear
5493:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

5495:    Logically Collective on SNES

5497:    Input Parameters:
5498: +  snes - the SNES context
5499: .  r - vector to store function value
5500: -  f - function evaluation routine

5502:    Notes:
5503:    The Newton-like methods typically solve linear systems of the form
5504: $      f'(x) x = -f(x),
5505:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

5507:    Level: beginner

5509:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5511: .keywords: SNES, nonlinear, set, function

5513: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5514: */
5515: PetscErrorCode  SNESSetFunctionMatlab(SNES snes,Vec r,const char *f,mxArray *ctx)
5516: {
5517:   PetscErrorCode    ierr;
5518:   SNESMatlabContext *sctx;

5521:   /* currently sctx is memory bleed */
5522:   PetscNew(&sctx);
5523:   PetscStrallocpy(f,&sctx->funcname);
5524:   /*
5525:      This should work, but it doesn't
5526:   sctx->ctx = ctx;
5527:   mexMakeArrayPersistent(sctx->ctx);
5528:   */
5529:   sctx->ctx = mxDuplicateArray(ctx);
5530:   SNESSetFunction(snes,r,SNESComputeFunction_Matlab,sctx);
5531:   return(0);
5532: }

5534: /*
5535:    SNESComputeJacobian_Matlab - Calls the function that has been set with SNESSetJacobianMatlab().

5537:    Collective on SNES

5539:    Input Parameters:
5540: +  snes - the SNES context
5541: .  x - input vector
5542: .  A, B - the matrices
5543: -  ctx - user context

5545:    Level: developer

5547: .keywords: SNES, nonlinear, compute, function

5549: .seealso: SNESSetFunction(), SNESGetFunction()
5550: @*/
5551: PetscErrorCode  SNESComputeJacobian_Matlab(SNES snes,Vec x,Mat A,Mat B,void *ctx)
5552: {
5553:   PetscErrorCode    ierr;
5554:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5555:   int               nlhs  = 2,nrhs = 6;
5556:   mxArray           *plhs[2],*prhs[6];
5557:   long long int     lx = 0,lA = 0,ls = 0, lB = 0;


5563:   /* call Matlab function in ctx with arguments x and y */

5565:   PetscMemcpy(&ls,&snes,sizeof(snes));
5566:   PetscMemcpy(&lx,&x,sizeof(x));
5567:   PetscMemcpy(&lA,A,sizeof(x));
5568:   PetscMemcpy(&lB,B,sizeof(x));
5569:   prhs[0] = mxCreateDoubleScalar((double)ls);
5570:   prhs[1] = mxCreateDoubleScalar((double)lx);
5571:   prhs[2] = mxCreateDoubleScalar((double)lA);
5572:   prhs[3] = mxCreateDoubleScalar((double)lB);
5573:   prhs[4] = mxCreateString(sctx->funcname);
5574:   prhs[5] = sctx->ctx;
5575:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeJacobianInternal");
5576:   mxGetScalar(plhs[0]);
5577:   mxDestroyArray(prhs[0]);
5578:   mxDestroyArray(prhs[1]);
5579:   mxDestroyArray(prhs[2]);
5580:   mxDestroyArray(prhs[3]);
5581:   mxDestroyArray(prhs[4]);
5582:   mxDestroyArray(plhs[0]);
5583:   mxDestroyArray(plhs[1]);
5584:   return(0);
5585: }

5587: /*
5588:    SNESSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
5589:    vector for use by the SNES routines in solving systems of nonlinear
5590:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

5592:    Logically Collective on SNES

5594:    Input Parameters:
5595: +  snes - the SNES context
5596: .  A,B - Jacobian matrices
5597: .  J - function evaluation routine
5598: -  ctx - user context

5600:    Level: developer

5602:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5604: .keywords: SNES, nonlinear, set, function

5606: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction(), J
5607: */
5608: PetscErrorCode  SNESSetJacobianMatlab(SNES snes,Mat A,Mat B,const char *J,mxArray *ctx)
5609: {
5610:   PetscErrorCode    ierr;
5611:   SNESMatlabContext *sctx;

5614:   /* currently sctx is memory bleed */
5615:   PetscNew(&sctx);
5616:   PetscStrallocpy(J,&sctx->funcname);
5617:   /*
5618:      This should work, but it doesn't
5619:   sctx->ctx = ctx;
5620:   mexMakeArrayPersistent(sctx->ctx);
5621:   */
5622:   sctx->ctx = mxDuplicateArray(ctx);
5623:   SNESSetJacobian(snes,A,B,SNESComputeJacobian_Matlab,sctx);
5624:   return(0);
5625: }

5627: /*
5628:    SNESMonitor_Matlab - Calls the function that has been set with SNESMonitorSetMatlab().

5630:    Collective on SNES

5632: .seealso: SNESSetFunction(), SNESGetFunction()
5633: @*/
5634: PetscErrorCode  SNESMonitor_Matlab(SNES snes,PetscInt it, PetscReal fnorm, void *ctx)
5635: {
5636:   PetscErrorCode    ierr;
5637:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5638:   int               nlhs  = 1,nrhs = 6;
5639:   mxArray           *plhs[1],*prhs[6];
5640:   long long int     lx = 0,ls = 0;
5641:   Vec               x  = snes->vec_sol;


5646:   PetscMemcpy(&ls,&snes,sizeof(snes));
5647:   PetscMemcpy(&lx,&x,sizeof(x));
5648:   prhs[0] = mxCreateDoubleScalar((double)ls);
5649:   prhs[1] = mxCreateDoubleScalar((double)it);
5650:   prhs[2] = mxCreateDoubleScalar((double)fnorm);
5651:   prhs[3] = mxCreateDoubleScalar((double)lx);
5652:   prhs[4] = mxCreateString(sctx->funcname);
5653:   prhs[5] = sctx->ctx;
5654:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESMonitorInternal");
5655:   mxGetScalar(plhs[0]);
5656:   mxDestroyArray(prhs[0]);
5657:   mxDestroyArray(prhs[1]);
5658:   mxDestroyArray(prhs[2]);
5659:   mxDestroyArray(prhs[3]);
5660:   mxDestroyArray(prhs[4]);
5661:   mxDestroyArray(plhs[0]);
5662:   return(0);
5663: }

5665: /*
5666:    SNESMonitorSetMatlab - Sets the monitor function from MATLAB

5668:    Level: developer

5670:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5672: .keywords: SNES, nonlinear, set, function

5674: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5675: */
5676: PetscErrorCode  SNESMonitorSetMatlab(SNES snes,const char *f,mxArray *ctx)
5677: {
5678:   PetscErrorCode    ierr;
5679:   SNESMatlabContext *sctx;

5682:   /* currently sctx is memory bleed */
5683:   PetscNew(&sctx);
5684:   PetscStrallocpy(f,&sctx->funcname);
5685:   /*
5686:      This should work, but it doesn't
5687:   sctx->ctx = ctx;
5688:   mexMakeArrayPersistent(sctx->ctx);
5689:   */
5690:   sctx->ctx = mxDuplicateArray(ctx);
5691:   SNESMonitorSet(snes,SNESMonitor_Matlab,sctx,NULL);
5692:   return(0);
5693: }

5695: #endif