Actual source code: snes.c

petsc-3.6.0 2015-06-09
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  2: #include <petsc/private/snesimpl.h>      /*I "petscsnes.h"  I*/
  3: #include <petscdmshell.h>

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

  8: /* Logging support */
  9: PetscClassId  SNES_CLASSID, DMSNES_CLASSID;
 10: PetscLogEvent SNES_Solve, SNES_FunctionEval, SNES_JacobianEval, SNES_NGSEval, SNES_NGSFuncEval, SNES_NPCSolve;

 14: /*@
 15:    SNESSetErrorIfNotConverged - Causes SNESSolve() to generate an error if the solver has not converged.

 17:    Logically Collective on SNES

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

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

 26:    Level: intermediate

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

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

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

 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: }

 75: /*@
 76:    SNESSetFunctionDomainError - tells SNES that the input vector to your SNESFunction is not
 77:      in the functions domain. For example, negative pressure.

 79:    Logically Collective on SNES

 81:    Input Parameters:
 82: .  snes - the SNES context

 84:    Level: advanced

 86: .keywords: SNES, view

 88: .seealso: SNESCreate(), SNESSetFunction(), SNESFunction
 89: @*/
 90: PetscErrorCode  SNESSetFunctionDomainError(SNES snes)
 91: {
 94:   if (snes->errorifnotconverged) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"User code indicates input vector is not in the function domain");
 95:   snes->domainerror = PETSC_TRUE;
 96:   return(0);
 97: }

101: /*@
102:    SNESGetFunctionDomainError - Gets the status of the domain error after a call to SNESComputeFunction;

104:    Logically Collective on SNES

106:    Input Parameters:
107: .  snes - the SNES context

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

112:    Level: advanced

114: .keywords: SNES, view

116: .seealso: SNESSetFunctionDomainError(), SNESComputeFunction()
117: @*/
118: PetscErrorCode  SNESGetFunctionDomainError(SNES snes, PetscBool *domainerror)
119: {
123:   *domainerror = snes->domainerror;
124:   return(0);
125: }

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

132:   Collective on PetscViewer

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

139:    Level: intermediate

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

144:   Notes for advanced users:
145:   Most users should not need to know the details of the binary storage
146:   format, since SNESLoad() and TSView() completely hide these details.
147:   But for anyone who's interested, the standard binary matrix storage
148:   format is
149: .vb
150:      has not yet been determined
151: .ve

153: .seealso: PetscViewerBinaryOpen(), SNESView(), MatLoad(), VecLoad()
154: @*/
155: PetscErrorCode  SNESLoad(SNES snes, PetscViewer viewer)
156: {
158:   PetscBool      isbinary;
159:   PetscInt       classid;
160:   char           type[256];
161:   KSP            ksp;
162:   DM             dm;
163:   DMSNES         dmsnes;

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

171:   PetscViewerBinaryRead(viewer,&classid,1,NULL,PETSC_INT);
172:   if (classid != SNES_FILE_CLASSID) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONG,"Not SNES next in file");
173:   PetscViewerBinaryRead(viewer,type,256,NULL,PETSC_CHAR);
174:   SNESSetType(snes, type);
175:   if (snes->ops->load) {
176:     (*snes->ops->load)(snes,viewer);
177:   }
178:   SNESGetDM(snes,&dm);
179:   DMGetDMSNES(dm,&dmsnes);
180:   DMSNESLoad(dmsnes,viewer);
181:   SNESGetKSP(snes,&ksp);
182:   KSPLoad(ksp,viewer);
183:   return(0);
184: }

186: #include <petscdraw.h>
187: #if defined(PETSC_HAVE_SAWS)
188: #include <petscviewersaws.h>
189: #endif
192: /*@C
193:    SNESView - Prints the SNES data structure.

195:    Collective on SNES

197:    Input Parameters:
198: +  SNES - the SNES context
199: -  viewer - visualization context

201:    Options Database Key:
202: .  -snes_view - Calls SNESView() at end of SNESSolve()

204:    Notes:
205:    The available visualization contexts include
206: +     PETSC_VIEWER_STDOUT_SELF - standard output (default)
207: -     PETSC_VIEWER_STDOUT_WORLD - synchronized standard
208:          output where only the first processor opens
209:          the file.  All other processors send their
210:          data to the first processor to print.

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

215:    Level: beginner

217: .keywords: SNES, view

219: .seealso: PetscViewerASCIIOpen()
220: @*/
221: PetscErrorCode  SNESView(SNES snes,PetscViewer viewer)
222: {
223:   SNESKSPEW      *kctx;
225:   KSP            ksp;
226:   SNESLineSearch linesearch;
227:   PetscBool      iascii,isstring,isbinary,isdraw;
228:   DMSNES         dmsnes;
229: #if defined(PETSC_HAVE_SAWS)
230:   PetscBool      issaws;
231: #endif

235:   if (!viewer) {
236:     PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&viewer);
237:   }

241:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
242:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);
243:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);
244:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);
245: #if defined(PETSC_HAVE_SAWS)
246:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSAWS,&issaws);
247: #endif
248:   if (iascii) {
249:     SNESNormSchedule normschedule;

251:     PetscObjectPrintClassNamePrefixType((PetscObject)snes,viewer);
252:     if (!snes->setupcalled) {
253:       PetscViewerASCIIPrintf(viewer,"  SNES has not been set up so information may be incomplete\n");
254:     }
255:     if (snes->ops->view) {
256:       PetscViewerASCIIPushTab(viewer);
257:       (*snes->ops->view)(snes,viewer);
258:       PetscViewerASCIIPopTab(viewer);
259:     }
260:     PetscViewerASCIIPrintf(viewer,"  maximum iterations=%D, maximum function evaluations=%D\n",snes->max_its,snes->max_funcs);
261:     PetscViewerASCIIPrintf(viewer,"  tolerances: relative=%g, absolute=%g, solution=%g\n",(double)snes->rtol,(double)snes->abstol,(double)snes->stol);
262:     PetscViewerASCIIPrintf(viewer,"  total number of linear solver iterations=%D\n",snes->linear_its);
263:     PetscViewerASCIIPrintf(viewer,"  total number of function evaluations=%D\n",snes->nfuncs);
264:     SNESGetNormSchedule(snes, &normschedule);
265:     if (normschedule > 0) {PetscViewerASCIIPrintf(viewer,"  norm schedule %s\n",SNESNormSchedules[normschedule]);}
266:     if (snes->gridsequence) {
267:       PetscViewerASCIIPrintf(viewer,"  total number of grid sequence refinements=%D\n",snes->gridsequence);
268:     }
269:     if (snes->ksp_ewconv) {
270:       kctx = (SNESKSPEW*)snes->kspconvctx;
271:       if (kctx) {
272:         PetscViewerASCIIPrintf(viewer,"  Eisenstat-Walker computation of KSP relative tolerance (version %D)\n",kctx->version);
273:         PetscViewerASCIIPrintf(viewer,"    rtol_0=%g, rtol_max=%g, threshold=%g\n",(double)kctx->rtol_0,(double)kctx->rtol_max,(double)kctx->threshold);
274:         PetscViewerASCIIPrintf(viewer,"    gamma=%g, alpha=%g, alpha2=%g\n",(double)kctx->gamma,(double)kctx->alpha,(double)kctx->alpha2);
275:       }
276:     }
277:     if (snes->lagpreconditioner == -1) {
278:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is never rebuilt\n");
279:     } else if (snes->lagpreconditioner > 1) {
280:       PetscViewerASCIIPrintf(viewer,"  Preconditioned is rebuilt every %D new Jacobians\n",snes->lagpreconditioner);
281:     }
282:     if (snes->lagjacobian == -1) {
283:       PetscViewerASCIIPrintf(viewer,"  Jacobian is never rebuilt\n");
284:     } else if (snes->lagjacobian > 1) {
285:       PetscViewerASCIIPrintf(viewer,"  Jacobian is rebuilt every %D SNES iterations\n",snes->lagjacobian);
286:     }
287:   } else if (isstring) {
288:     const char *type;
289:     SNESGetType(snes,&type);
290:     PetscViewerStringSPrintf(viewer," %-3.3s",type);
291:   } else if (isbinary) {
292:     PetscInt    classid = SNES_FILE_CLASSID;
293:     MPI_Comm    comm;
294:     PetscMPIInt rank;
295:     char        type[256];

297:     PetscObjectGetComm((PetscObject)snes,&comm);
298:     MPI_Comm_rank(comm,&rank);
299:     if (!rank) {
300:       PetscViewerBinaryWrite(viewer,&classid,1,PETSC_INT,PETSC_FALSE);
301:       PetscStrncpy(type,((PetscObject)snes)->type_name,sizeof(type));
302:       PetscViewerBinaryWrite(viewer,type,sizeof(type),PETSC_CHAR,PETSC_FALSE);
303:     }
304:     if (snes->ops->view) {
305:       (*snes->ops->view)(snes,viewer);
306:     }
307:   } else if (isdraw) {
308:     PetscDraw draw;
309:     char      str[36];
310:     PetscReal x,y,bottom,h;

312:     PetscViewerDrawGetDraw(viewer,0,&draw);
313:     PetscDrawGetCurrentPoint(draw,&x,&y);
314:     PetscStrcpy(str,"SNES: ");
315:     PetscStrcat(str,((PetscObject)snes)->type_name);
316:     PetscDrawStringBoxed(draw,x,y,PETSC_DRAW_BLUE,PETSC_DRAW_BLACK,str,NULL,&h);
317:     bottom = y - h;
318:     PetscDrawPushCurrentPoint(draw,x,bottom);
319:     if (snes->ops->view) {
320:       (*snes->ops->view)(snes,viewer);
321:     }
322: #if defined(PETSC_HAVE_SAWS)
323:   } else if (issaws) {
324:     PetscMPIInt rank;
325:     const char *name;

327:     PetscObjectGetName((PetscObject)snes,&name);
328:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
329:     if (!((PetscObject)snes)->amsmem && !rank) {
330:       char       dir[1024];

332:       PetscObjectViewSAWs((PetscObject)snes,viewer);
333:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/its",name);
334:       PetscStackCallSAWs(SAWs_Register,(dir,&snes->iter,1,SAWs_READ,SAWs_INT));
335:       if (!snes->conv_hist) {
336:         SNESSetConvergenceHistory(snes,NULL,NULL,PETSC_DECIDE,PETSC_TRUE);
337:       }
338:       PetscSNPrintf(dir,1024,"/PETSc/Objects/%s/conv_hist",name);
339:       PetscStackCallSAWs(SAWs_Register,(dir,snes->conv_hist,10,SAWs_READ,SAWs_DOUBLE));
340:     }
341: #endif
342:   }
343:   if (snes->linesearch) {
344:     PetscViewerASCIIPushTab(viewer);
345:     SNESGetLineSearch(snes, &linesearch);
346:     SNESLineSearchView(linesearch, viewer);
347:     PetscViewerASCIIPopTab(viewer);
348:   }
349:   if (snes->pc && snes->usespc) {
350:     PetscViewerASCIIPushTab(viewer);
351:     SNESView(snes->pc, viewer);
352:     PetscViewerASCIIPopTab(viewer);
353:   }
354:   PetscViewerASCIIPushTab(viewer);
355:   DMGetDMSNES(snes->dm,&dmsnes);
356:   DMSNESView(dmsnes, viewer);
357:   PetscViewerASCIIPopTab(viewer);
358:   if (snes->usesksp) {
359:     SNESGetKSP(snes,&ksp);
360:     PetscViewerASCIIPushTab(viewer);
361:     KSPView(ksp,viewer);
362:     PetscViewerASCIIPopTab(viewer);
363:   }
364:   if (isdraw) {
365:     PetscDraw draw;
366:     PetscViewerDrawGetDraw(viewer,0,&draw);
367:     PetscDrawPopCurrentPoint(draw);
368:   }
369:   return(0);
370: }

372: /*
373:   We retain a list of functions that also take SNES command
374:   line options. These are called at the end SNESSetFromOptions()
375: */
376: #define MAXSETFROMOPTIONS 5
377: static PetscInt numberofsetfromoptions;
378: static PetscErrorCode (*othersetfromoptions[MAXSETFROMOPTIONS])(SNES);

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

385:   Not Collective

387:   Input Parameter:
388: . snescheck - function that checks for options

390:   Level: developer

392: .seealso: SNESSetFromOptions()
393: @*/
394: PetscErrorCode  SNESAddOptionsChecker(PetscErrorCode (*snescheck)(SNES))
395: {
397:   if (numberofsetfromoptions >= MAXSETFROMOPTIONS) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "Too many options checkers, only %D allowed", MAXSETFROMOPTIONS);
398:   othersetfromoptions[numberofsetfromoptions++] = snescheck;
399:   return(0);
400: }

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

406: static PetscErrorCode SNESSetUpMatrixFree_Private(SNES snes, PetscBool hasOperator, PetscInt version)
407: {
408:   Mat            J;
409:   KSP            ksp;
410:   PC             pc;
411:   PetscBool      match;


417:   if (!snes->vec_func && (snes->jacobian || snes->jacobian_pre)) {
418:     Mat A = snes->jacobian, B = snes->jacobian_pre;
419:     MatCreateVecs(A ? A : B, NULL,&snes->vec_func);
420:   }

422:   if (version == 1) {
423:     MatCreateSNESMF(snes,&J);
424:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
425:     MatSetFromOptions(J);
426:   } else if (version == 2) {
427:     if (!snes->vec_func) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SNESSetFunction() must be called first");
428: #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_REAL_SINGLE) && !defined(PETSC_USE_REAL___FLOAT128)
429:     SNESDefaultMatrixFreeCreate2(snes,snes->vec_func,&J);
430: #else
431:     SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP, "matrix-free operator rutines (version 2)");
432: #endif
433:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE, "matrix-free operator rutines, only version 1 and 2");

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

438:     /* This version replaces the user provided Jacobian matrix with a
439:        matrix-free version but still employs the user-provided preconditioner matrix. */
440:     SNESSetJacobian(snes,J,0,0,0);
441:   } else {
442:     /* This version replaces both the user-provided Jacobian and the user-
443:      provided preconditioner Jacobian with the default matrix free version. */
444:     if ((snes->pcside == PC_LEFT) && snes->pc) {
445:       if (!snes->jacobian){SNESSetJacobian(snes,J,0,0,0);}
446:     } else {
447:       SNESSetJacobian(snes,J,J,MatMFFDComputeJacobian,0);
448:     }
449:     /* Force no preconditioner */
450:     SNESGetKSP(snes,&ksp);
451:     KSPGetPC(ksp,&pc);
452:     PetscObjectTypeCompare((PetscObject)pc,PCSHELL,&match);
453:     if (!match) {
454:       PetscInfo(snes,"Setting default matrix-free preconditioner routines\nThat is no preconditioner is being used\n");
455:       PCSetType(pc,PCNONE);
456:     }
457:   }
458:   MatDestroy(&J);
459:   return(0);
460: }

464: static PetscErrorCode DMRestrictHook_SNESVecSol(DM dmfine,Mat Restrict,Vec Rscale,Mat Inject,DM dmcoarse,void *ctx)
465: {
466:   SNES           snes = (SNES)ctx;
468:   Vec            Xfine,Xfine_named = NULL,Xcoarse;

471:   if (PetscLogPrintInfo) {
472:     PetscInt finelevel,coarselevel,fineclevel,coarseclevel;
473:     DMGetRefineLevel(dmfine,&finelevel);
474:     DMGetCoarsenLevel(dmfine,&fineclevel);
475:     DMGetRefineLevel(dmcoarse,&coarselevel);
476:     DMGetCoarsenLevel(dmcoarse,&coarseclevel);
477:     PetscInfo4(dmfine,"Restricting SNES solution vector from level %D-%D to level %D-%D\n",finelevel,fineclevel,coarselevel,coarseclevel);
478:   }
479:   if (dmfine == snes->dm) Xfine = snes->vec_sol;
480:   else {
481:     DMGetNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);
482:     Xfine = Xfine_named;
483:   }
484:   DMGetNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
485:   if (Inject) {
486:     MatRestrict(Inject,Xfine,Xcoarse);
487:   } else {
488:     MatRestrict(Restrict,Xfine,Xcoarse);
489:     VecPointwiseMult(Xcoarse,Xcoarse,Rscale);
490:   }
491:   DMRestoreNamedGlobalVector(dmcoarse,"SNESVecSol",&Xcoarse);
492:   if (Xfine_named) {DMRestoreNamedGlobalVector(dmfine,"SNESVecSol",&Xfine_named);}
493:   return(0);
494: }

498: static PetscErrorCode DMCoarsenHook_SNESVecSol(DM dm,DM dmc,void *ctx)
499: {

503:   DMCoarsenHookAdd(dmc,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,ctx);
504:   return(0);
505: }

509: /* This may be called to rediscretize the operator on levels of linear multigrid. The DM shuffle is so the user can
510:  * safely call SNESGetDM() in their residual evaluation routine. */
511: static PetscErrorCode KSPComputeOperators_SNES(KSP ksp,Mat A,Mat B,void *ctx)
512: {
513:   SNES           snes = (SNES)ctx;
515:   Mat            Asave = A,Bsave = B;
516:   Vec            X,Xnamed = NULL;
517:   DM             dmsave;
518:   void           *ctxsave;
519:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);

522:   dmsave = snes->dm;
523:   KSPGetDM(ksp,&snes->dm);
524:   if (dmsave == snes->dm) X = snes->vec_sol; /* We are on the finest level */
525:   else {                                     /* We are on a coarser level, this vec was initialized using a DM restrict hook */
526:     DMGetNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
527:     X    = Xnamed;
528:     SNESGetJacobian(snes,NULL,NULL,&jac,&ctxsave);
529:     /* If the DM's don't match up, the MatFDColoring context needed for the jacobian won't match up either -- fixit. */
530:     if (jac == SNESComputeJacobianDefaultColor) {
531:       SNESSetJacobian(snes,NULL,NULL,SNESComputeJacobianDefaultColor,0);
532:     }
533:   }
534:   /* put the previous context back */

536:   SNESComputeJacobian(snes,X,A,B);
537:   if (snes->dm != dmsave && jac == SNESComputeJacobianDefaultColor) {
538:     SNESSetJacobian(snes,NULL,NULL,jac,ctxsave);
539:   }

541:   if (A != Asave || B != Bsave) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_SUP,"No support for changing matrices at this time");
542:   if (Xnamed) {
543:     DMRestoreNamedGlobalVector(snes->dm,"SNESVecSol",&Xnamed);
544:   }
545:   snes->dm = dmsave;
546:   return(0);
547: }

551: /*@
552:    SNESSetUpMatrices - ensures that matrices are available for SNES, to be called by SNESSetUp_XXX()

554:    Collective

556:    Input Arguments:
557: .  snes - snes to configure

559:    Level: developer

561: .seealso: SNESSetUp()
562: @*/
563: PetscErrorCode SNESSetUpMatrices(SNES snes)
564: {
566:   DM             dm;
567:   DMSNES         sdm;

570:   SNESGetDM(snes,&dm);
571:   DMGetDMSNES(dm,&sdm);
572:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_PLIB,"DMSNES not properly configured");
573:   else if (!snes->jacobian && snes->mf) {
574:     Mat  J;
575:     void *functx;
576:     MatCreateSNESMF(snes,&J);
577:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
578:     MatSetFromOptions(J);
579:     SNESGetFunction(snes,NULL,NULL,&functx);
580:     SNESSetJacobian(snes,J,J,0,0);
581:     MatDestroy(&J);
582:   } else if (snes->mf_operator && !snes->jacobian_pre && !snes->jacobian) {
583:     Mat J,B;
584:     MatCreateSNESMF(snes,&J);
585:     MatMFFDSetOptionsPrefix(J,((PetscObject)snes)->prefix);
586:     MatSetFromOptions(J);
587:     DMCreateMatrix(snes->dm,&B);
588:     /* sdm->computejacobian was already set to reach here */
589:     SNESSetJacobian(snes,J,B,NULL,NULL);
590:     MatDestroy(&J);
591:     MatDestroy(&B);
592:   } else if (!snes->jacobian_pre) {
593:     Mat J,B;
594:     J    = snes->jacobian;
595:     DMCreateMatrix(snes->dm,&B);
596:     SNESSetJacobian(snes,J ? J : B,B,NULL,NULL);
597:     MatDestroy(&B);
598:   }
599:   {
600:     KSP ksp;
601:     SNESGetKSP(snes,&ksp);
602:     KSPSetComputeOperators(ksp,KSPComputeOperators_SNES,snes);
603:     DMCoarsenHookAdd(snes->dm,DMCoarsenHook_SNESVecSol,DMRestrictHook_SNESVecSol,snes);
604:   }
605:   return(0);
606: }

610: /*@
611:    SNESSetFromOptions - Sets various SNES and KSP parameters from user options.

613:    Collective on SNES

615:    Input Parameter:
616: .  snes - the SNES context

618:    Options Database Keys:
619: +  -snes_type <type> - newtonls, newtontr, ngmres, ncg, nrichardson, qn, vi, fas, SNESType for complete list
620: .  -snes_stol - convergence tolerance in terms of the norm
621:                 of the change in the solution between steps
622: .  -snes_atol <abstol> - absolute tolerance of residual norm
623: .  -snes_rtol <rtol> - relative decrease in tolerance norm from initial
624: .  -snes_max_it <max_it> - maximum number of iterations
625: .  -snes_max_funcs <max_funcs> - maximum number of function evaluations
626: .  -snes_max_fail <max_fail> - maximum number of line search failures allowed before stopping, default is none
627: .  -snes_max_linear_solve_fail - number of linear solver failures before SNESSolve() stops
628: .  -snes_lag_preconditioner <lag> - how often preconditioner is rebuilt (use -1 to never rebuild)
629: .  -snes_lag_jacobian <lag> - how often Jacobian is rebuilt (use -1 to never rebuild)
630: .  -snes_trtol <trtol> - trust region tolerance
631: .  -snes_no_convergence_test - skip convergence test in nonlinear
632:                                solver; hence iterations will continue until max_it
633:                                or some other criterion is reached. Saves expense
634:                                of convergence test
635: .  -snes_monitor <optional filename> - prints residual norm at each iteration. if no
636:                                        filename given prints to stdout
637: .  -snes_monitor_solution - plots solution at each iteration
638: .  -snes_monitor_residual - plots residual (not its norm) at each iteration
639: .  -snes_monitor_solution_update - plots update to solution at each iteration
640: .  -snes_monitor_lg_residualnorm - plots residual norm at each iteration
641: .  -snes_monitor_lg_range - plots residual norm at each iteration
642: .  -snes_fd - use finite differences to compute Jacobian; very slow, only for testing
643: .  -snes_fd_color - use finite differences with coloring to compute Jacobian
644: .  -snes_mf_ksp_monitor - if using matrix-free multiply then print h at each KSP iteration
645: -  -snes_converged_reason - print the reason for convergence/divergence after each solve

647:     Options Database for Eisenstat-Walker method:
648: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
649: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
650: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
651: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
652: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
653: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
654: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
655: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

657:    Notes:
658:    To see all options, run your program with the -help option or consult
659:    Users-Manual: ch_snes

661:    Level: beginner

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

665: .seealso: SNESSetOptionsPrefix()
666: @*/
667: PetscErrorCode  SNESSetFromOptions(SNES snes)
668: {
669:   PetscBool      flg,pcset,persist,set;
670:   PetscInt       i,indx,lag,grids;
671:   const char     *deft        = SNESNEWTONLS;
672:   const char     *convtests[] = {"default","skip"};
673:   SNESKSPEW      *kctx        = NULL;
674:   char           type[256], monfilename[PETSC_MAX_PATH_LEN];
675:   PetscViewer    monviewer;
677:   PCSide         pcside;
678:   const char     *optionsprefix;

682:   SNESRegisterAll();
683:   PetscObjectOptionsBegin((PetscObject)snes);
684:   if (((PetscObject)snes)->type_name) deft = ((PetscObject)snes)->type_name;
685:   PetscOptionsFList("-snes_type","Nonlinear solver method","SNESSetType",SNESList,deft,type,256,&flg);
686:   if (flg) {
687:     SNESSetType(snes,type);
688:   } else if (!((PetscObject)snes)->type_name) {
689:     SNESSetType(snes,deft);
690:   }
691:   PetscOptionsReal("-snes_stol","Stop if step length less than","SNESSetTolerances",snes->stol,&snes->stol,NULL);
692:   PetscOptionsReal("-snes_atol","Stop if function norm less than","SNESSetTolerances",snes->abstol,&snes->abstol,NULL);

694:   PetscOptionsReal("-snes_rtol","Stop if decrease in function norm less than","SNESSetTolerances",snes->rtol,&snes->rtol,NULL);
695:   PetscOptionsInt("-snes_max_it","Maximum iterations","SNESSetTolerances",snes->max_its,&snes->max_its,NULL);
696:   PetscOptionsInt("-snes_max_funcs","Maximum function evaluations","SNESSetTolerances",snes->max_funcs,&snes->max_funcs,NULL);
697:   PetscOptionsInt("-snes_max_fail","Maximum nonlinear step failures","SNESSetMaxNonlinearStepFailures",snes->maxFailures,&snes->maxFailures,NULL);
698:   PetscOptionsInt("-snes_max_linear_solve_fail","Maximum failures in linear solves allowed","SNESSetMaxLinearSolveFailures",snes->maxLinearSolveFailures,&snes->maxLinearSolveFailures,NULL);
699:   PetscOptionsBool("-snes_error_if_not_converged","Generate error if solver does not converge","SNESSetErrorIfNotConverged",snes->errorifnotconverged,&snes->errorifnotconverged,NULL);

701:   PetscOptionsInt("-snes_lag_preconditioner","How often to rebuild preconditioner","SNESSetLagPreconditioner",snes->lagpreconditioner,&lag,&flg);
702:   if (flg) {
703:     SNESSetLagPreconditioner(snes,lag);
704:   }
705:   PetscOptionsBool("-snes_lag_preconditioner_persists","Preconditioner lagging through multiple solves","SNESSetLagPreconditionerPersists",snes->lagjac_persist,&persist,&flg);
706:   if (flg) {
707:     SNESSetLagPreconditionerPersists(snes,persist);
708:   }
709:   PetscOptionsInt("-snes_lag_jacobian","How often to rebuild Jacobian","SNESSetLagJacobian",snes->lagjacobian,&lag,&flg);
710:   if (flg) {
711:     SNESSetLagJacobian(snes,lag);
712:   }
713:   PetscOptionsBool("-snes_lag_jacobian_persists","Jacobian lagging through multiple solves","SNESSetLagJacobianPersists",snes->lagjac_persist,&persist,&flg);
714:   if (flg) {
715:     SNESSetLagJacobianPersists(snes,persist);
716:   }

718:   PetscOptionsInt("-snes_grid_sequence","Use grid sequencing to generate initial guess","SNESSetGridSequence",snes->gridsequence,&grids,&flg);
719:   if (flg) {
720:     SNESSetGridSequence(snes,grids);
721:   }

723:   PetscOptionsEList("-snes_convergence_test","Convergence test","SNESSetConvergenceTest",convtests,2,"default",&indx,&flg);
724:   if (flg) {
725:     switch (indx) {
726:     case 0: SNESSetConvergenceTest(snes,SNESConvergedDefault,NULL,NULL); break;
727:     case 1: SNESSetConvergenceTest(snes,SNESConvergedSkip,NULL,NULL);    break;
728:     }
729:   }

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

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

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

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

741:   PetscOptionsInt("-snes_ksp_ew_version","Version 1, 2 or 3","SNESKSPSetParametersEW",kctx->version,&kctx->version,NULL);
742:   PetscOptionsReal("-snes_ksp_ew_rtol0","0 <= rtol0 < 1","SNESKSPSetParametersEW",kctx->rtol_0,&kctx->rtol_0,NULL);
743:   PetscOptionsReal("-snes_ksp_ew_rtolmax","0 <= rtolmax < 1","SNESKSPSetParametersEW",kctx->rtol_max,&kctx->rtol_max,NULL);
744:   PetscOptionsReal("-snes_ksp_ew_gamma","0 <= gamma <= 1","SNESKSPSetParametersEW",kctx->gamma,&kctx->gamma,NULL);
745:   PetscOptionsReal("-snes_ksp_ew_alpha","1 < alpha <= 2","SNESKSPSetParametersEW",kctx->alpha,&kctx->alpha,NULL);
746:   PetscOptionsReal("-snes_ksp_ew_alpha2","alpha2","SNESKSPSetParametersEW",kctx->alpha2,&kctx->alpha2,NULL);
747:   PetscOptionsReal("-snes_ksp_ew_threshold","0 < threshold < 1","SNESKSPSetParametersEW",kctx->threshold,&kctx->threshold,NULL);

749:   flg  = PETSC_FALSE;
750:   PetscOptionsBool("-snes_check_jacobian","Check each Jacobian with a differenced one","SNESUpdateCheckJacobian",flg,&flg,&set);
751:   if (set && flg) {
752:     SNESSetUpdate(snes,SNESUpdateCheckJacobian);
753:   }

755:   flg  = PETSC_FALSE;
756:   PetscOptionsBool("-snes_monitor_cancel","Remove all monitors","SNESMonitorCancel",flg,&flg,&set);
757:   if (set && flg) {SNESMonitorCancel(snes);}

759:   PetscOptionsString("-snes_monitor","Monitor norm of function","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
760:   if (flg) {
761:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
762:     SNESMonitorSet(snes,SNESMonitorDefault,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);
763:   }

765:   PetscOptionsString("-snes_monitor_range","Monitor range of elements of function","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
766:   if (flg) {
767:     SNESMonitorSet(snes,SNESMonitorRange,0,0);
768:   }

770:   PetscOptionsString("-snes_ratiomonitor","Monitor ratios of norms of function","SNESMonitorSetRatio","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
771:   if (flg) {
772:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
773:     SNESMonitorSetRatio(snes,monviewer);
774:   }

776:   PetscOptionsString("-snes_monitor_short","Monitor norm of function (fewer digits)","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
777:   if (flg) {
778:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
779:     SNESMonitorSet(snes,SNESMonitorDefaultShort,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);
780:   }

782:   PetscOptionsString("-snes_monitor_field","Monitor norm of function (split into fields)","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
783:   if (flg) {
784:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
785:     SNESMonitorSet(snes,SNESMonitorDefaultField,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);
786:   }

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

791:   flg  = PETSC_FALSE;
792:   PetscOptionsBool("-snes_monitor_solution","Plot solution at each iteration","SNESMonitorSolution",flg,&flg,NULL);
793:   if (flg) {SNESMonitorSet(snes,SNESMonitorSolution,0,0);}
794:   flg  = PETSC_FALSE;
795:   PetscOptionsBool("-snes_monitor_solution_update","Plot correction at each iteration","SNESMonitorSolutionUpdate",flg,&flg,NULL);
796:   if (flg) {SNESMonitorSet(snes,SNESMonitorSolutionUpdate,0,0);}
797:   flg  = PETSC_FALSE;
798:   PetscOptionsBool("-snes_monitor_residual","Plot residual at each iteration","SNESMonitorResidual",flg,&flg,NULL);
799:   if (flg) {SNESMonitorSet(snes,SNESMonitorResidual,0,0);}
800:   flg  = PETSC_FALSE;
801:   PetscOptionsBool("-snes_monitor_lg_residualnorm","Plot function norm at each iteration","SNESMonitorLGResidualNorm",flg,&flg,NULL);
802:   if (flg) {
803:     PetscObject *objs;

805:     SNESMonitorLGCreate(0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,&objs);
806:     SNESMonitorSet(snes,(PetscErrorCode (*)(SNES,PetscInt,PetscReal,void*))SNESMonitorLGResidualNorm,objs,(PetscErrorCode (*)(void**))SNESMonitorLGDestroy);
807:   }
808:   flg  = PETSC_FALSE;
809:   PetscOptionsBool("-snes_monitor_lg_range","Plot function range at each iteration","SNESMonitorLGRange",flg,&flg,NULL);
810:   if (flg) {
811:     PetscViewer ctx;

813:     PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,0,PETSC_DECIDE,PETSC_DECIDE,300,300,&ctx);
814:     SNESMonitorSet(snes,SNESMonitorLGRange,ctx,(PetscErrorCode (*)(void**))PetscViewerDestroy);
815:   }

817:   flg  = PETSC_FALSE;
818:   PetscOptionsBool("-snes_monitor_jacupdate_spectrum","Print the change in the spectrum of the Jacobian","SNESMonitorJacUpdateSpectrum",flg,&flg,NULL);
819:   if (flg) {SNESMonitorSet(snes,SNESMonitorJacUpdateSpectrum,0,0);}


822:   PetscOptionsString("-snes_monitor_fields","Monitor norm of function per field","SNESMonitorSet","stdout",monfilename,PETSC_MAX_PATH_LEN,&flg);
823:   if (flg) {
824:     PetscViewerASCIIOpen(PetscObjectComm((PetscObject)snes),monfilename,&monviewer);
825:     SNESMonitorSet(snes,SNESMonitorFields,monviewer,(PetscErrorCode (*)(void**))PetscViewerDestroy);
826:   }

828:   flg  = PETSC_FALSE;
829:   PetscOptionsBool("-snes_fd","Use finite differences (slow) to compute Jacobian","SNESComputeJacobianDefault",flg,&flg,NULL);
830:   if (flg) {
831:     void *functx;
832:     SNESGetFunction(snes,NULL,NULL,&functx);
833:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefault,functx);
834:     PetscInfo(snes,"Setting default finite difference Jacobian matrix\n");
835:   }

837:   flg  = PETSC_FALSE;
838:   PetscOptionsBool("-snes_fd_function","Use finite differences (slow) to compute function from user objective","SNESObjectiveComputeFunctionDefaultFD",flg,&flg,NULL);
839:   if (flg) {
840:     SNESSetFunction(snes,NULL,SNESObjectiveComputeFunctionDefaultFD,NULL);
841:   }

843:   flg  = PETSC_FALSE;
844:   PetscOptionsBool("-snes_fd_color","Use finite differences with coloring to compute Jacobian","SNESComputeJacobianDefaultColor",flg,&flg,NULL);
845:   if (flg) {
846:     DM             dm;
847:     DMSNES         sdm;
848:     SNESGetDM(snes,&dm);
849:     DMGetDMSNES(dm,&sdm);
850:     sdm->jacobianctx = NULL;
851:     SNESSetJacobian(snes,snes->jacobian,snes->jacobian_pre,SNESComputeJacobianDefaultColor,0);
852:     PetscInfo(snes,"Setting default finite difference coloring Jacobian matrix\n");
853:   }

855:   flg  = PETSC_FALSE;
856:   PetscOptionsBool("-snes_mf_operator","Use a Matrix-Free Jacobian with user-provided preconditioner matrix","MatCreateSNESMF",PETSC_FALSE,&snes->mf_operator,&flg);
857:   if (flg && snes->mf_operator) {
858:     snes->mf_operator = PETSC_TRUE;
859:     snes->mf          = PETSC_TRUE;
860:   }
861:   flg  = PETSC_FALSE;
862:   PetscOptionsBool("-snes_mf","Use a Matrix-Free Jacobian with no preconditioner matrix","MatCreateSNESMF",PETSC_FALSE,&snes->mf,&flg);
863:   if (!flg && snes->mf_operator) snes->mf = PETSC_TRUE;
864:   PetscOptionsInt("-snes_mf_version","Matrix-Free routines version 1 or 2","None",snes->mf_version,&snes->mf_version,0);

866:   flg  = PETSC_FALSE;
867:   SNESGetNPCSide(snes,&pcside);
868:   PetscOptionsEnum("-snes_npc_side","SNES nonlinear preconditioner side","SNESSetNPCSide",PCSides,(PetscEnum)pcside,(PetscEnum*)&pcside,&flg);
869:   if (flg) {SNESSetNPCSide(snes,pcside);}

871: #if defined(PETSC_HAVE_SAWS)
872:   /*
873:     Publish convergence information using SAWs
874:   */
875:   flg  = PETSC_FALSE;
876:   PetscOptionsBool("-snes_monitor_saws","Publish SNES progress using SAWs","SNESMonitorSet",flg,&flg,NULL);
877:   if (flg) {
878:     void *ctx;
879:     SNESMonitorSAWsCreate(snes,&ctx);
880:     SNESMonitorSet(snes,SNESMonitorSAWs,ctx,SNESMonitorSAWsDestroy);
881:   }
882: #endif
883: #if defined(PETSC_HAVE_SAWS)
884:   {
885:   PetscBool set;
886:   flg  = PETSC_FALSE;
887:   PetscOptionsBool("-snes_saws_block","Block for SAWs at end of SNESSolve","PetscObjectSAWsBlock",((PetscObject)snes)->amspublishblock,&flg,&set);
888:   if (set) {
889:     PetscObjectSAWsSetBlock((PetscObject)snes,flg);
890:   }
891:   }
892: #endif

894:   for (i = 0; i < numberofsetfromoptions; i++) {
895:     (*othersetfromoptions[i])(snes);
896:   }

898:   if (snes->ops->setfromoptions) {
899:     (*snes->ops->setfromoptions)(PetscOptionsObject,snes);
900:   }

902:   /* process any options handlers added with PetscObjectAddOptionsHandler() */
903:   PetscObjectProcessOptionsHandlers((PetscObject)snes);
904:   PetscOptionsEnd();

906:   if (!snes->linesearch) {
907:     SNESGetLineSearch(snes, &snes->linesearch);
908:   }
909:   SNESLineSearchSetFromOptions(snes->linesearch);

911:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
912:   KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);
913:   KSPSetFromOptions(snes->ksp);

915:   /* if someone has set the SNES NPC type, create it. */
916:   SNESGetOptionsPrefix(snes, &optionsprefix);
917:   PetscOptionsHasName(optionsprefix, "-npc_snes_type", &pcset);
918:   if (pcset && (!snes->pc)) {
919:     SNESGetNPC(snes, &snes->pc);
920:   }
921:   return(0);
922: }

926: /*@C
927:    SNESSetComputeApplicationContext - Sets an optional function to compute a user-defined context for
928:    the nonlinear solvers.

930:    Logically Collective on SNES

932:    Input Parameters:
933: +  snes - the SNES context
934: .  compute - function to compute the context
935: -  destroy - function to destroy the context

937:    Level: intermediate

939:    Notes:
940:    This function is currently not available from Fortran.

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

944: .seealso: SNESGetApplicationContext(), SNESSetComputeApplicationContext(), SNESGetApplicationContext()
945: @*/
946: PetscErrorCode  SNESSetComputeApplicationContext(SNES snes,PetscErrorCode (*compute)(SNES,void**),PetscErrorCode (*destroy)(void**))
947: {
950:   snes->ops->usercompute = compute;
951:   snes->ops->userdestroy = destroy;
952:   return(0);
953: }

957: /*@
958:    SNESSetApplicationContext - Sets the optional user-defined context for
959:    the nonlinear solvers.

961:    Logically Collective on SNES

963:    Input Parameters:
964: +  snes - the SNES context
965: -  usrP - optional user context

967:    Level: intermediate

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

971: .seealso: SNESGetApplicationContext()
972: @*/
973: PetscErrorCode  SNESSetApplicationContext(SNES snes,void *usrP)
974: {
976:   KSP            ksp;

980:   SNESGetKSP(snes,&ksp);
981:   KSPSetApplicationContext(ksp,usrP);
982:   snes->user = usrP;
983:   return(0);
984: }

988: /*@
989:    SNESGetApplicationContext - Gets the user-defined context for the
990:    nonlinear solvers.

992:    Not Collective

994:    Input Parameter:
995: .  snes - SNES context

997:    Output Parameter:
998: .  usrP - user context

1000:    Level: intermediate

1002: .keywords: SNES, nonlinear, get, application, context

1004: .seealso: SNESSetApplicationContext()
1005: @*/
1006: PetscErrorCode  SNESGetApplicationContext(SNES snes,void *usrP)
1007: {
1010:   *(void**)usrP = snes->user;
1011:   return(0);
1012: }

1016: /*@
1017:    SNESGetIterationNumber - Gets the number of nonlinear iterations completed
1018:    at this time.

1020:    Not Collective

1022:    Input Parameter:
1023: .  snes - SNES context

1025:    Output Parameter:
1026: .  iter - iteration number

1028:    Notes:
1029:    For example, during the computation of iteration 2 this would return 1.

1031:    This is useful for using lagged Jacobians (where one does not recompute the
1032:    Jacobian at each SNES iteration). For example, the code
1033: .vb
1034:       SNESGetIterationNumber(snes,&it);
1035:       if (!(it % 2)) {
1036:         [compute Jacobian here]
1037:       }
1038: .ve
1039:    can be used in your ComputeJacobian() function to cause the Jacobian to be
1040:    recomputed every second SNES iteration.

1042:    Level: intermediate

1044: .keywords: SNES, nonlinear, get, iteration, number,

1046: .seealso:   SNESGetLinearSolveIterations()
1047: @*/
1048: PetscErrorCode  SNESGetIterationNumber(SNES snes,PetscInt *iter)
1049: {
1053:   *iter = snes->iter;
1054:   return(0);
1055: }

1059: /*@
1060:    SNESSetIterationNumber - Sets the current iteration number.

1062:    Not Collective

1064:    Input Parameter:
1065: .  snes - SNES context
1066: .  iter - iteration number

1068:    Level: developer

1070: .keywords: SNES, nonlinear, set, iteration, number,

1072: .seealso:   SNESGetLinearSolveIterations()
1073: @*/
1074: PetscErrorCode  SNESSetIterationNumber(SNES snes,PetscInt iter)
1075: {

1080:   PetscObjectSAWsTakeAccess((PetscObject)snes);
1081:   snes->iter = iter;
1082:   PetscObjectSAWsGrantAccess((PetscObject)snes);
1083:   return(0);
1084: }

1088: /*@
1089:    SNESGetNonlinearStepFailures - Gets the number of unsuccessful steps
1090:    attempted by the nonlinear solver.

1092:    Not Collective

1094:    Input Parameter:
1095: .  snes - SNES context

1097:    Output Parameter:
1098: .  nfails - number of unsuccessful steps attempted

1100:    Notes:
1101:    This counter is reset to zero for each successive call to SNESSolve().

1103:    Level: intermediate

1105: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1107: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1108:           SNESSetMaxNonlinearStepFailures(), SNESGetMaxNonlinearStepFailures()
1109: @*/
1110: PetscErrorCode  SNESGetNonlinearStepFailures(SNES snes,PetscInt *nfails)
1111: {
1115:   *nfails = snes->numFailures;
1116:   return(0);
1117: }

1121: /*@
1122:    SNESSetMaxNonlinearStepFailures - Sets the maximum number of unsuccessful steps
1123:    attempted by the nonlinear solver before it gives up.

1125:    Not Collective

1127:    Input Parameters:
1128: +  snes     - SNES context
1129: -  maxFails - maximum of unsuccessful steps

1131:    Level: intermediate

1133: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1135: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1136:           SNESGetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()
1137: @*/
1138: PetscErrorCode  SNESSetMaxNonlinearStepFailures(SNES snes, PetscInt maxFails)
1139: {
1142:   snes->maxFailures = maxFails;
1143:   return(0);
1144: }

1148: /*@
1149:    SNESGetMaxNonlinearStepFailures - Gets the maximum number of unsuccessful steps
1150:    attempted by the nonlinear solver before it gives up.

1152:    Not Collective

1154:    Input Parameter:
1155: .  snes     - SNES context

1157:    Output Parameter:
1158: .  maxFails - maximum of unsuccessful steps

1160:    Level: intermediate

1162: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1164: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(),
1165:           SNESSetMaxNonlinearStepFailures(), SNESGetNonlinearStepFailures()

1167: @*/
1168: PetscErrorCode  SNESGetMaxNonlinearStepFailures(SNES snes, PetscInt *maxFails)
1169: {
1173:   *maxFails = snes->maxFailures;
1174:   return(0);
1175: }

1179: /*@
1180:    SNESGetNumberFunctionEvals - Gets the number of user provided function evaluations
1181:      done by SNES.

1183:    Not Collective

1185:    Input Parameter:
1186: .  snes     - SNES context

1188:    Output Parameter:
1189: .  nfuncs - number of evaluations

1191:    Level: intermediate

1193:    Notes: Reset every time SNESSolve is called unless SNESSetCountersReset() is used.

1195: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1197: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(), SNESGetLinearSolveFailures(), SNESSetCountersReset()
1198: @*/
1199: PetscErrorCode  SNESGetNumberFunctionEvals(SNES snes, PetscInt *nfuncs)
1200: {
1204:   *nfuncs = snes->nfuncs;
1205:   return(0);
1206: }

1210: /*@
1211:    SNESGetLinearSolveFailures - Gets the number of failed (non-converged)
1212:    linear solvers.

1214:    Not Collective

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

1219:    Output Parameter:
1220: .  nfails - number of failed solves

1222:    Level: intermediate

1224:    Options Database Keys:
1225: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1227:    Notes:
1228:    This counter is reset to zero for each successive call to SNESSolve().

1230: .keywords: SNES, nonlinear, get, number, unsuccessful, steps

1232: .seealso: SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures()
1233: @*/
1234: PetscErrorCode  SNESGetLinearSolveFailures(SNES snes,PetscInt *nfails)
1235: {
1239:   *nfails = snes->numLinearSolveFailures;
1240:   return(0);
1241: }

1245: /*@
1246:    SNESSetMaxLinearSolveFailures - the number of failed linear solve attempts
1247:    allowed before SNES returns with a diverged reason of SNES_DIVERGED_LINEAR_SOLVE

1249:    Logically Collective on SNES

1251:    Input Parameters:
1252: +  snes     - SNES context
1253: -  maxFails - maximum allowed linear solve failures

1255:    Level: intermediate

1257:    Options Database Keys:
1258: . -snes_max_linear_solve_fail <num> - The number of failures before the solve is terminated

1260:    Notes: By default this is 0; that is SNES returns on the first failed linear solve

1262: .keywords: SNES, nonlinear, set, maximum, unsuccessful, steps

1264: .seealso: SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESGetLinearSolveIterations()
1265: @*/
1266: PetscErrorCode  SNESSetMaxLinearSolveFailures(SNES snes, PetscInt maxFails)
1267: {
1271:   snes->maxLinearSolveFailures = maxFails;
1272:   return(0);
1273: }

1277: /*@
1278:    SNESGetMaxLinearSolveFailures - gets the maximum number of linear solve failures that
1279:      are allowed before SNES terminates

1281:    Not Collective

1283:    Input Parameter:
1284: .  snes     - SNES context

1286:    Output Parameter:
1287: .  maxFails - maximum of unsuccessful solves allowed

1289:    Level: intermediate

1291:    Notes: By default this is 1; that is SNES returns on the first failed linear solve

1293: .keywords: SNES, nonlinear, get, maximum, unsuccessful, steps

1295: .seealso: SNESGetLinearSolveFailures(), SNESGetLinearSolveIterations(), SNESSetMaxLinearSolveFailures(),
1296: @*/
1297: PetscErrorCode  SNESGetMaxLinearSolveFailures(SNES snes, PetscInt *maxFails)
1298: {
1302:   *maxFails = snes->maxLinearSolveFailures;
1303:   return(0);
1304: }

1308: /*@
1309:    SNESGetLinearSolveIterations - Gets the total number of linear iterations
1310:    used by the nonlinear solver.

1312:    Not Collective

1314:    Input Parameter:
1315: .  snes - SNES context

1317:    Output Parameter:
1318: .  lits - number of linear iterations

1320:    Notes:
1321:    This counter is reset to zero for each successive call to SNESSolve() unless SNESSetCountersReset() is used.

1323:    Level: intermediate

1325: .keywords: SNES, nonlinear, get, number, linear, iterations

1327: .seealso:  SNESGetIterationNumber(), SNESGetLinearSolveFailures(), SNESGetMaxLinearSolveFailures(), SNESSetCountersReset()
1328: @*/
1329: PetscErrorCode  SNESGetLinearSolveIterations(SNES snes,PetscInt *lits)
1330: {
1334:   *lits = snes->linear_its;
1335:   return(0);
1336: }

1340: /*@
1341:    SNESSetCountersReset - Sets whether or not the counters for linear iterations and function evaluations
1342:    are reset every time SNESSolve() is called.

1344:    Logically Collective on SNES

1346:    Input Parameter:
1347: +  snes - SNES context
1348: -  reset - whether to reset the counters or not

1350:    Notes:
1351:    This defaults to PETSC_TRUE

1353:    Level: developer

1355: .keywords: SNES, nonlinear, set, reset, number, linear, iterations

1357: .seealso:  SNESGetNumberFunctionEvals(), SNESGetLinearSolveIterations(), SNESGetNPC()
1358: @*/
1359: PetscErrorCode  SNESSetCountersReset(SNES snes,PetscBool reset)
1360: {
1364:   snes->counters_reset = reset;
1365:   return(0);
1366: }


1371: /*@
1372:    SNESSetKSP - Sets a KSP context for the SNES object to use

1374:    Not Collective, but the SNES and KSP objects must live on the same MPI_Comm

1376:    Input Parameters:
1377: +  snes - the SNES context
1378: -  ksp - the KSP context

1380:    Notes:
1381:    The SNES object already has its KSP object, you can obtain with SNESGetKSP()
1382:    so this routine is rarely needed.

1384:    The KSP object that is already in the SNES object has its reference count
1385:    decreased by one.

1387:    Level: developer

1389: .keywords: SNES, nonlinear, get, KSP, context

1391: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
1392: @*/
1393: PetscErrorCode  SNESSetKSP(SNES snes,KSP ksp)
1394: {

1401:   PetscObjectReference((PetscObject)ksp);
1402:   if (snes->ksp) {PetscObjectDereference((PetscObject)snes->ksp);}
1403:   snes->ksp = ksp;
1404:   return(0);
1405: }

1407: /* -----------------------------------------------------------*/
1410: /*@
1411:    SNESCreate - Creates a nonlinear solver context.

1413:    Collective on MPI_Comm

1415:    Input Parameters:
1416: .  comm - MPI communicator

1418:    Output Parameter:
1419: .  outsnes - the new SNES context

1421:    Options Database Keys:
1422: +   -snes_mf - Activates default matrix-free Jacobian-vector products,
1423:                and no preconditioning matrix
1424: .   -snes_mf_operator - Activates default matrix-free Jacobian-vector
1425:                products, and a user-provided preconditioning matrix
1426:                as set by SNESSetJacobian()
1427: -   -snes_fd - Uses (slow!) finite differences to compute Jacobian

1429:    Level: beginner

1431: .keywords: SNES, nonlinear, create, context

1433: .seealso: SNESSolve(), SNESDestroy(), SNES, SNESSetLagPreconditioner()

1435: @*/
1436: PetscErrorCode  SNESCreate(MPI_Comm comm,SNES *outsnes)
1437: {
1439:   SNES           snes;
1440:   SNESKSPEW      *kctx;

1444:   *outsnes = NULL;
1445:   SNESInitializePackage();

1447:   PetscHeaderCreate(snes,SNES_CLASSID,"SNES","Nonlinear solver","SNES",comm,SNESDestroy,SNESView);

1449:   snes->ops->converged    = SNESConvergedDefault;
1450:   snes->usesksp           = PETSC_TRUE;
1451:   snes->tolerancesset     = PETSC_FALSE;
1452:   snes->max_its           = 50;
1453:   snes->max_funcs         = 10000;
1454:   snes->norm              = 0.0;
1455:   snes->normschedule      = SNES_NORM_ALWAYS;
1456:   snes->functype          = SNES_FUNCTION_DEFAULT;
1457: #if defined(PETSC_USE_REAL_SINGLE)
1458:   snes->rtol              = 1.e-5;
1459: #else
1460:   snes->rtol              = 1.e-8;
1461: #endif
1462:   snes->ttol              = 0.0;
1463: #if defined(PETSC_USE_REAL_SINGLE)
1464:   snes->abstol            = 1.e-25;
1465: #else
1466:   snes->abstol            = 1.e-50;
1467: #endif
1468:   snes->stol              = 1.e-8;
1469: #if defined(PETSC_USE_REAL_SINGLE)
1470:   snes->deltatol          = 1.e-6;
1471: #else
1472:   snes->deltatol          = 1.e-12;
1473: #endif
1474:   snes->nfuncs            = 0;
1475:   snes->numFailures       = 0;
1476:   snes->maxFailures       = 1;
1477:   snes->linear_its        = 0;
1478:   snes->lagjacobian       = 1;
1479:   snes->jac_iter          = 0;
1480:   snes->lagjac_persist    = PETSC_FALSE;
1481:   snes->lagpreconditioner = 1;
1482:   snes->pre_iter          = 0;
1483:   snes->lagpre_persist    = PETSC_FALSE;
1484:   snes->numbermonitors    = 0;
1485:   snes->data              = 0;
1486:   snes->setupcalled       = PETSC_FALSE;
1487:   snes->ksp_ewconv        = PETSC_FALSE;
1488:   snes->nwork             = 0;
1489:   snes->work              = 0;
1490:   snes->nvwork            = 0;
1491:   snes->vwork             = 0;
1492:   snes->conv_hist_len     = 0;
1493:   snes->conv_hist_max     = 0;
1494:   snes->conv_hist         = NULL;
1495:   snes->conv_hist_its     = NULL;
1496:   snes->conv_hist_reset   = PETSC_TRUE;
1497:   snes->counters_reset    = PETSC_TRUE;
1498:   snes->vec_func_init_set = PETSC_FALSE;
1499:   snes->reason            = SNES_CONVERGED_ITERATING;
1500:   snes->pcside            = PC_RIGHT;

1502:   snes->mf          = PETSC_FALSE;
1503:   snes->mf_operator = PETSC_FALSE;
1504:   snes->mf_version  = 1;

1506:   snes->numLinearSolveFailures = 0;
1507:   snes->maxLinearSolveFailures = 1;

1509:   snes->vizerotolerance = 1.e-8;

1511:   /* Create context to compute Eisenstat-Walker relative tolerance for KSP */
1512:   PetscNewLog(snes,&kctx);

1514:   snes->kspconvctx  = (void*)kctx;
1515:   kctx->version     = 2;
1516:   kctx->rtol_0      = .3; /* Eisenstat and Walker suggest rtol_0=.5, but
1517:                              this was too large for some test cases */
1518:   kctx->rtol_last   = 0.0;
1519:   kctx->rtol_max    = .9;
1520:   kctx->gamma       = 1.0;
1521:   kctx->alpha       = .5*(1.0 + PetscSqrtReal(5.0));
1522:   kctx->alpha2      = kctx->alpha;
1523:   kctx->threshold   = .1;
1524:   kctx->lresid_last = 0.0;
1525:   kctx->norm_last   = 0.0;

1527:   *outsnes = snes;
1528:   return(0);
1529: }

1531: /*MC
1532:     SNESFunction - Functional form used to convey the nonlinear function to be solved by SNES

1534:      Synopsis:
1535:      #include "petscsnes.h"
1536:      PetscErrorCode SNESFunction(SNES snes,Vec x,Vec f,void *ctx);

1538:      Input Parameters:
1539: +     snes - the SNES context
1540: .     x    - state at which to evaluate residual
1541: -     ctx     - optional user-defined function context, passed in with SNESSetFunction()

1543:      Output Parameter:
1544: .     f  - vector to put residual (function value)

1546:    Level: intermediate

1548: .seealso:   SNESSetFunction(), SNESGetFunction()
1549: M*/

1553: /*@C
1554:    SNESSetFunction - Sets the function evaluation routine and function
1555:    vector for use by the SNES routines in solving systems of nonlinear
1556:    equations.

1558:    Logically Collective on SNES

1560:    Input Parameters:
1561: +  snes - the SNES context
1562: .  r - vector to store function value
1563: .  f - function evaluation routine; see SNESFunction for calling sequence details
1564: -  ctx - [optional] user-defined context for private data for the
1565:          function evaluation routine (may be NULL)

1567:    Notes:
1568:    The Newton-like methods typically solve linear systems of the form
1569: $      f'(x) x = -f(x),
1570:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

1572:    Level: beginner

1574: .keywords: SNES, nonlinear, set, function

1576: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetPicard(), SNESFunction
1577: @*/
1578: PetscErrorCode  SNESSetFunction(SNES snes,Vec r,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1579: {
1581:   DM             dm;

1585:   if (r) {
1588:     PetscObjectReference((PetscObject)r);
1589:     VecDestroy(&snes->vec_func);

1591:     snes->vec_func = r;
1592:   }
1593:   SNESGetDM(snes,&dm);
1594:   DMSNESSetFunction(dm,f,ctx);
1595:   return(0);
1596: }


1601: /*@C
1602:    SNESSetInitialFunction - Sets the function vector to be used as the
1603:    function norm at the initialization of the method.  In some
1604:    instances, the user has precomputed the function before calling
1605:    SNESSolve.  This function allows one to avoid a redundant call
1606:    to SNESComputeFunction in that case.

1608:    Logically Collective on SNES

1610:    Input Parameters:
1611: +  snes - the SNES context
1612: -  f - vector to store function value

1614:    Notes:
1615:    This should not be modified during the solution procedure.

1617:    This is used extensively in the SNESFAS hierarchy and in nonlinear preconditioning.

1619:    Level: developer

1621: .keywords: SNES, nonlinear, set, function

1623: .seealso: SNESSetFunction(), SNESComputeFunction(), SNESSetInitialFunctionNorm()
1624: @*/
1625: PetscErrorCode  SNESSetInitialFunction(SNES snes, Vec f)
1626: {
1628:   Vec            vec_func;

1634:   if (snes->pcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
1635:     snes->vec_func_init_set = PETSC_FALSE;
1636:     return(0);
1637:   }
1638:   SNESGetFunction(snes,&vec_func,NULL,NULL);
1639:   VecCopy(f, vec_func);

1641:   snes->vec_func_init_set = PETSC_TRUE;
1642:   return(0);
1643: }

1647: /*@
1648:    SNESSetNormSchedule - Sets the SNESNormSchedule used in covergence and monitoring
1649:    of the SNES method.

1651:    Logically Collective on SNES

1653:    Input Parameters:
1654: +  snes - the SNES context
1655: -  normschedule - the frequency of norm computation

1657:    Options Database Key:
1658: .  -snes_norm_schedule <none, always, initialonly, finalonly, initalfinalonly>

1660:    Notes:
1661:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1662:    of the nonlinear function and the taking of its norm at every iteration to
1663:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1664:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1665:    may either be monitored for convergence or not.  As these are often used as nonlinear
1666:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1667:    their solution.

1669:    Level: developer

1671: .keywords: SNES, nonlinear, set, function, norm, type

1673: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1674: @*/
1675: PetscErrorCode  SNESSetNormSchedule(SNES snes, SNESNormSchedule normschedule)
1676: {
1679:   snes->normschedule = normschedule;
1680:   return(0);
1681: }


1686: /*@
1687:    SNESGetNormSchedule - Gets the SNESNormSchedule used in covergence and monitoring
1688:    of the SNES method.

1690:    Logically Collective on SNES

1692:    Input Parameters:
1693: +  snes - the SNES context
1694: -  normschedule - the type of the norm used

1696:    Level: advanced

1698: .keywords: SNES, nonlinear, set, function, norm, type

1700: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1701: @*/
1702: PetscErrorCode  SNESGetNormSchedule(SNES snes, SNESNormSchedule *normschedule)
1703: {
1706:   *normschedule = snes->normschedule;
1707:   return(0);
1708: }


1713: /*@C
1714:    SNESSetFunctionType - Sets the SNESNormSchedule used in covergence and monitoring
1715:    of the SNES method.

1717:    Logically Collective on SNES

1719:    Input Parameters:
1720: +  snes - the SNES context
1721: -  normschedule - the frequency of norm computation

1723:    Notes:
1724:    Only certain SNES methods support certain SNESNormSchedules.  Most require evaluation
1725:    of the nonlinear function and the taking of its norm at every iteration to
1726:    even ensure convergence at all.  However, methods such as custom Gauss-Seidel methods
1727:    (SNESNGS) and the like do not require the norm of the function to be computed, and therfore
1728:    may either be monitored for convergence or not.  As these are often used as nonlinear
1729:    preconditioners, monitoring the norm of their error is not a useful enterprise within
1730:    their solution.

1732:    Level: developer

1734: .keywords: SNES, nonlinear, set, function, norm, type

1736: .seealso: SNESGetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1737: @*/
1738: PetscErrorCode  SNESSetFunctionType(SNES snes, SNESFunctionType type)
1739: {
1742:   snes->functype = type;
1743:   return(0);
1744: }


1749: /*@C
1750:    SNESGetFunctionType - Gets the SNESNormSchedule used in covergence and monitoring
1751:    of the SNES method.

1753:    Logically Collective on SNES

1755:    Input Parameters:
1756: +  snes - the SNES context
1757: -  normschedule - the type of the norm used

1759:    Level: advanced

1761: .keywords: SNES, nonlinear, set, function, norm, type

1763: .seealso: SNESSetNormSchedule(), SNESComputeFunction(), VecNorm(), SNESSetFunction(), SNESSetInitialFunction(), SNESNormSchedule
1764: @*/
1765: PetscErrorCode  SNESGetFunctionType(SNES snes, SNESFunctionType *type)
1766: {
1769:   *type = snes->functype;
1770:   return(0);
1771: }

1773: /*MC
1774:     SNESNGSFunction - function used to convey a Gauss-Seidel sweep on the nonlinear function

1776:      Synopsis:
1777:      #include <petscsnes.h>
1778: $    SNESNGSFunction(SNES snes,Vec x,Vec b,void *ctx);

1780: +  X   - solution vector
1781: .  B   - RHS vector
1782: -  ctx - optional user-defined Gauss-Seidel context

1784:    Level: intermediate

1786: .seealso:   SNESSetNGS(), SNESGetNGS()
1787: M*/

1791: /*@C
1792:    SNESSetNGS - Sets the user nonlinear Gauss-Seidel routine for
1793:    use with composed nonlinear solvers.

1795:    Input Parameters:
1796: +  snes   - the SNES context
1797: .  f - function evaluation routine to apply Gauss-Seidel see SNESNGSFunction
1798: -  ctx    - [optional] user-defined context for private data for the
1799:             smoother evaluation routine (may be NULL)

1801:    Notes:
1802:    The NGS routines are used by the composed nonlinear solver to generate
1803:     a problem appropriate update to the solution, particularly FAS.

1805:    Level: intermediate

1807: .keywords: SNES, nonlinear, set, Gauss-Seidel

1809: .seealso: SNESGetFunction(), SNESComputeNGS()
1810: @*/
1811: PetscErrorCode SNESSetNGS(SNES snes,PetscErrorCode (*f)(SNES,Vec,Vec,void*),void *ctx)
1812: {
1814:   DM             dm;

1818:   SNESGetDM(snes,&dm);
1819:   DMSNESSetNGS(dm,f,ctx);
1820:   return(0);
1821: }

1825: PETSC_EXTERN PetscErrorCode SNESPicardComputeFunction(SNES snes,Vec x,Vec f,void *ctx)
1826: {
1828:   DM             dm;
1829:   DMSNES         sdm;

1832:   SNESGetDM(snes,&dm);
1833:   DMGetDMSNES(dm,&sdm);
1834:   /*  A(x)*x - b(x) */
1835:   if (sdm->ops->computepfunction) {
1836:     (*sdm->ops->computepfunction)(snes,x,f,sdm->pctx);
1837:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard function.");

1839:   if (sdm->ops->computepjacobian) {
1840:     (*sdm->ops->computepjacobian)(snes,x,snes->jacobian,snes->jacobian_pre,sdm->pctx);
1841:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetPicard() to provide Picard matrix.");
1842:   VecScale(f,-1.0);
1843:   MatMultAdd(snes->jacobian,x,f,f);
1844:   return(0);
1845: }

1849: PETSC_EXTERN PetscErrorCode SNESPicardComputeJacobian(SNES snes,Vec x1,Mat J,Mat B,void *ctx)
1850: {
1852:   /* the jacobian matrix should be pre-filled in SNESPicardComputeFunction */
1853:   return(0);
1854: }

1858: /*@C
1859:    SNESSetPicard - Use SNES to solve the semilinear-system A(x) x = b(x) via a Picard type iteration (Picard linearization)

1861:    Logically Collective on SNES

1863:    Input Parameters:
1864: +  snes - the SNES context
1865: .  r - vector to store function value
1866: .  b - function evaluation routine
1867: .  Amat - matrix with which A(x) x - b(x) is to be computed
1868: .  Pmat - matrix from which preconditioner is computed (usually the same as Amat)
1869: .  J  - function to compute matrix value, see SNESJacobianFunction for details on its calling sequence
1870: -  ctx - [optional] user-defined context for private data for the
1871:          function evaluation routine (may be NULL)

1873:    Notes:
1874:     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
1875:     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.

1877:     One can call SNESSetPicard() or SNESSetFunction() (and possibly SNESSetJacobian()) but cannot call both

1879: $     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}
1880: $     Note that when an exact solver is used this corresponds to the "classic" Picard A(x^{n}) x^{n+1} = b(x^{n}) iteration.

1882:      Run with -snes_mf_operator to solve the system with Newton's method using A(x^{n}) to construct the preconditioner.

1884:    We implement the defect correction form of the Picard iteration because it converges much more generally when inexact linear solvers are used then
1885:    the direct Picard iteration A(x^n) x^{n+1} = b(x^n)

1887:    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
1888:    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
1889:    different please contact us at petsc-dev@mcs.anl.gov and we'll have an entirely new argument :-).

1891:    Level: intermediate

1893: .keywords: SNES, nonlinear, set, function

1895: .seealso: SNESGetFunction(), SNESSetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESGetPicard(), SNESLineSearchPreCheckPicard(), SNESJacobianFunction
1896: @*/
1897: 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)
1898: {
1900:   DM             dm;

1904:   SNESGetDM(snes, &dm);
1905:   DMSNESSetPicard(dm,b,J,ctx);
1906:   SNESSetFunction(snes,r,SNESPicardComputeFunction,ctx);
1907:   SNESSetJacobian(snes,Amat,Pmat,SNESPicardComputeJacobian,ctx);
1908:   return(0);
1909: }

1913: /*@C
1914:    SNESGetPicard - Returns the context for the Picard iteration

1916:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

1918:    Input Parameter:
1919: .  snes - the SNES context

1921:    Output Parameter:
1922: +  r - the function (or NULL)
1923: .  f - the function (or NULL); see SNESFunction for calling sequence details
1924: .  Amat - the matrix used to defined the operation A(x) x - b(x) (or NULL)
1925: .  Pmat  - the matrix from which the preconditioner will be constructed (or NULL)
1926: .  J - the function for matrix evaluation (or NULL); see SNESJacobianFunction for calling sequence details
1927: -  ctx - the function context (or NULL)

1929:    Level: advanced

1931: .keywords: SNES, nonlinear, get, function

1933: .seealso: SNESSetPicard(), SNESGetFunction(), SNESGetJacobian(), SNESGetDM(), SNESFunction, SNESJacobianFunction
1934: @*/
1935: 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)
1936: {
1938:   DM             dm;

1942:   SNESGetFunction(snes,r,NULL,NULL);
1943:   SNESGetJacobian(snes,Amat,Pmat,NULL,NULL);
1944:   SNESGetDM(snes,&dm);
1945:   DMSNESGetPicard(dm,f,J,ctx);
1946:   return(0);
1947: }

1951: /*@C
1952:    SNESSetComputeInitialGuess - Sets a routine used to compute an initial guess for the problem

1954:    Logically Collective on SNES

1956:    Input Parameters:
1957: +  snes - the SNES context
1958: .  func - function evaluation routine
1959: -  ctx - [optional] user-defined context for private data for the
1960:          function evaluation routine (may be NULL)

1962:    Calling sequence of func:
1963: $    func (SNES snes,Vec x,void *ctx);

1965: .  f - function vector
1966: -  ctx - optional user-defined function context

1968:    Level: intermediate

1970: .keywords: SNES, nonlinear, set, function

1972: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian()
1973: @*/
1974: PetscErrorCode  SNESSetComputeInitialGuess(SNES snes,PetscErrorCode (*func)(SNES,Vec,void*),void *ctx)
1975: {
1978:   if (func) snes->ops->computeinitialguess = func;
1979:   if (ctx)  snes->initialguessP            = ctx;
1980:   return(0);
1981: }

1983: /* --------------------------------------------------------------- */
1986: /*@C
1987:    SNESGetRhs - Gets the vector for solving F(x) = rhs. If rhs is not set
1988:    it assumes a zero right hand side.

1990:    Logically Collective on SNES

1992:    Input Parameter:
1993: .  snes - the SNES context

1995:    Output Parameter:
1996: .  rhs - the right hand side vector or NULL if the right hand side vector is null

1998:    Level: intermediate

2000: .keywords: SNES, nonlinear, get, function, right hand side

2002: .seealso: SNESGetSolution(), SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
2003: @*/
2004: PetscErrorCode  SNESGetRhs(SNES snes,Vec *rhs)
2005: {
2009:   *rhs = snes->vec_rhs;
2010:   return(0);
2011: }

2015: /*@
2016:    SNESComputeFunction - Calls the function that has been set with SNESSetFunction().

2018:    Collective on SNES

2020:    Input Parameters:
2021: +  snes - the SNES context
2022: -  x - input vector

2024:    Output Parameter:
2025: .  y - function vector, as set by SNESSetFunction()

2027:    Notes:
2028:    SNESComputeFunction() is typically used within nonlinear solvers
2029:    implementations, so most users would not generally call this routine
2030:    themselves.

2032:    Level: developer

2034: .keywords: SNES, nonlinear, compute, function

2036: .seealso: SNESSetFunction(), SNESGetFunction()
2037: @*/
2038: PetscErrorCode  SNESComputeFunction(SNES snes,Vec x,Vec y)
2039: {
2041:   DM             dm;
2042:   DMSNES         sdm;

2050:   VecValidValues(x,2,PETSC_TRUE);

2052:   SNESGetDM(snes,&dm);
2053:   DMGetDMSNES(dm,&sdm);
2054:   if (sdm->ops->computefunction) {
2055:     PetscLogEventBegin(SNES_FunctionEval,snes,x,y,0);
2056:     VecLockPush(x);
2057:     PetscStackPush("SNES user function");
2058:     (*sdm->ops->computefunction)(snes,x,y,sdm->functionctx);
2059:     PetscStackPop;
2060:     VecLockPop(x);
2061:     PetscLogEventEnd(SNES_FunctionEval,snes,x,y,0);
2062:   } else if (snes->vec_rhs) {
2063:     MatMult(snes->jacobian, x, y);
2064:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetFunction() or SNESSetDM() before SNESComputeFunction(), likely called from SNESSolve().");
2065:   if (snes->vec_rhs) {
2066:     VecAXPY(y,-1.0,snes->vec_rhs);
2067:   }
2068:   snes->nfuncs++;
2069:   /*
2070:      domainerror might not be set on all processes; so we tag vector locally with Inf and the next inner product or norm will
2071:      propagate the value to all processes
2072:   */
2073:   if (snes->domainerror) {
2074:     VecSetInf(y);
2075:   }
2076:   return(0);
2077: }

2081: /*@
2082:    SNESComputeNGS - Calls the Gauss-Seidel function that has been set with  SNESSetNGS().

2084:    Collective on SNES

2086:    Input Parameters:
2087: +  snes - the SNES context
2088: .  x - input vector
2089: -  b - rhs vector

2091:    Output Parameter:
2092: .  x - new solution vector

2094:    Notes:
2095:    SNESComputeNGS() is typically used within composed nonlinear solver
2096:    implementations, so most users would not generally call this routine
2097:    themselves.

2099:    Level: developer

2101: .keywords: SNES, nonlinear, compute, function

2103: .seealso: SNESSetNGS(), SNESComputeFunction()
2104: @*/
2105: PetscErrorCode  SNESComputeNGS(SNES snes,Vec b,Vec x)
2106: {
2108:   DM             dm;
2109:   DMSNES         sdm;

2117:   if (b) {VecValidValues(b,2,PETSC_TRUE);}
2118:   PetscLogEventBegin(SNES_NGSEval,snes,x,b,0);
2119:   SNESGetDM(snes,&dm);
2120:   DMGetDMSNES(dm,&sdm);
2121:   if (sdm->ops->computegs) {
2122:     if (b) {VecLockPush(b);}
2123:     PetscStackPush("SNES user NGS");
2124:     (*sdm->ops->computegs)(snes,x,b,sdm->gsctx);
2125:     PetscStackPop;
2126:     if (b) {VecLockPop(b);}
2127:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetNGS() before SNESComputeNGS(), likely called from SNESSolve().");
2128:   PetscLogEventEnd(SNES_NGSEval,snes,x,b,0);
2129:   return(0);
2130: }

2134: /*@
2135:    SNESComputeJacobian - Computes the Jacobian matrix that has been set with SNESSetJacobian().

2137:    Collective on SNES and Mat

2139:    Input Parameters:
2140: +  snes - the SNES context
2141: -  x - input vector

2143:    Output Parameters:
2144: +  A - Jacobian matrix
2145: -  B - optional preconditioning matrix

2147:   Options Database Keys:
2148: +    -snes_lag_preconditioner <lag>
2149: .    -snes_lag_jacobian <lag>
2150: .    -snes_compare_explicit - Compare the computed Jacobian to the finite difference Jacobian and output the differences
2151: .    -snes_compare_explicit_draw  - Compare the computed Jacobian to the finite difference Jacobian and draw the result
2152: .    -snes_compare_explicit_contour  - Compare the computed Jacobian to the finite difference Jacobian and draw a contour plot with the result
2153: .    -snes_compare_operator  - Make the comparison options above use the operator instead of the preconditioning matrix
2154: .    -snes_compare_coloring - Compute the finite differece Jacobian using coloring and display norms of difference
2155: .    -snes_compare_coloring_display - Compute the finite differece Jacobian using coloring and display verbose differences
2156: .    -snes_compare_coloring_threshold - Display only those matrix entries that differ by more than a given threshold
2157: .    -snes_compare_coloring_threshold_atol - Absolute tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2158: .    -snes_compare_coloring_threshold_rtol - Relative tolerance for difference in matrix entries to be displayed by -snes_compare_coloring_threshold
2159: .    -snes_compare_coloring_draw - Compute the finite differece Jacobian using coloring and draw differences
2160: -    -snes_compare_coloring_draw_contour - Compute the finite differece Jacobian using coloring and show contours of matrices and differences


2163:    Notes:
2164:    Most users should not need to explicitly call this routine, as it
2165:    is used internally within the nonlinear solvers.

2167:    Level: developer

2169: .keywords: SNES, compute, Jacobian, matrix

2171: .seealso:  SNESSetJacobian(), KSPSetOperators(), MatStructure, SNESSetLagPreconditioner(), SNESSetLagJacobian()
2172: @*/
2173: PetscErrorCode  SNESComputeJacobian(SNES snes,Vec X,Mat A,Mat B)
2174: {
2176:   PetscBool      flag;
2177:   DM             dm;
2178:   DMSNES         sdm;
2179:   KSP            ksp;

2185:   VecValidValues(X,2,PETSC_TRUE);
2186:   SNESGetDM(snes,&dm);
2187:   DMGetDMSNES(dm,&sdm);

2189:   if (!sdm->ops->computejacobian) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_USER,"Must call SNESSetJacobian(), DMSNESSetJacobian(), DMDASNESSetJacobianLocal(), etc");

2191:   /* make sure that MatAssemblyBegin/End() is called on A matrix if it is matrix free */

2193:   if (snes->lagjacobian == -2) {
2194:     snes->lagjacobian = -1;

2196:     PetscInfo(snes,"Recomputing Jacobian/preconditioner because lag is -2 (means compute Jacobian, but then never again) \n");
2197:   } else if (snes->lagjacobian == -1) {
2198:     PetscInfo(snes,"Reusing Jacobian/preconditioner because lag is -1\n");
2199:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2200:     if (flag) {
2201:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2202:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2203:     }
2204:     return(0);
2205:   } else if (snes->lagjacobian > 1 && (snes->iter + snes->jac_iter) % snes->lagjacobian) {
2206:     PetscInfo2(snes,"Reusing Jacobian/preconditioner because lag is %D and SNES iteration is %D\n",snes->lagjacobian,snes->iter);
2207:     PetscObjectTypeCompare((PetscObject)A,MATMFFD,&flag);
2208:     if (flag) {
2209:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2210:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2211:     }
2212:     return(0);
2213:   }
2214:   if (snes->pc && snes->pcside == PC_LEFT) {
2215:       MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
2216:       MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
2217:       return(0);
2218:   }

2220:   PetscLogEventBegin(SNES_JacobianEval,snes,X,A,B);
2221:   VecLockPush(X);
2222:   PetscStackPush("SNES user Jacobian function");
2223:   (*sdm->ops->computejacobian)(snes,X,A,B,sdm->jacobianctx);
2224:   PetscStackPop;
2225:   VecLockPop(X);
2226:   PetscLogEventEnd(SNES_JacobianEval,snes,X,A,B);

2228:   /* the next line ensures that snes->ksp exists */
2229:   SNESGetKSP(snes,&ksp);
2230:   if (snes->lagpreconditioner == -2) {
2231:     PetscInfo(snes,"Rebuilding preconditioner exactly once since lag is -2\n");
2232:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2233:     snes->lagpreconditioner = -1;
2234:   } else if (snes->lagpreconditioner == -1) {
2235:     PetscInfo(snes,"Reusing preconditioner because lag is -1\n");
2236:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2237:   } else if (snes->lagpreconditioner > 1 && (snes->iter + snes->pre_iter) % snes->lagpreconditioner) {
2238:     PetscInfo2(snes,"Reusing preconditioner because lag is %D and SNES iteration is %D\n",snes->lagpreconditioner,snes->iter);
2239:     KSPSetReusePreconditioner(snes->ksp,PETSC_TRUE);
2240:   } else {
2241:     PetscInfo(snes,"Rebuilding preconditioner\n");
2242:     KSPSetReusePreconditioner(snes->ksp,PETSC_FALSE);
2243:   }

2245:   /* make sure user returned a correct Jacobian and preconditioner */
2248:   {
2249:     PetscBool flag = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_operator = PETSC_FALSE;
2250:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_explicit",&flag,NULL);
2251:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_explicit_draw",&flag_draw,NULL);
2252:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_explicit_draw_contour",&flag_contour,NULL);
2253:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_operator",&flag_operator,NULL);
2254:     if (flag || flag_draw || flag_contour) {
2255:       Mat          Bexp_mine = NULL,Bexp,FDexp;
2256:       PetscViewer  vdraw,vstdout;
2257:       PetscBool    flg;
2258:       if (flag_operator) {
2259:         MatComputeExplicitOperator(A,&Bexp_mine);
2260:         Bexp = Bexp_mine;
2261:       } else {
2262:         /* See if the preconditioning matrix can be viewed and added directly */
2263:         PetscObjectTypeCompareAny((PetscObject)B,&flg,MATSEQAIJ,MATMPIAIJ,MATSEQDENSE,MATMPIDENSE,MATSEQBAIJ,MATMPIBAIJ,MATSEQSBAIJ,MATMPIBAIJ,"");
2264:         if (flg) Bexp = B;
2265:         else {
2266:           /* If the "preconditioning" matrix is itself MATSHELL or some other type without direct support */
2267:           MatComputeExplicitOperator(B,&Bexp_mine);
2268:           Bexp = Bexp_mine;
2269:         }
2270:       }
2271:       MatConvert(Bexp,MATSAME,MAT_INITIAL_MATRIX,&FDexp);
2272:       SNESComputeJacobianDefault(snes,X,FDexp,FDexp,NULL);
2273:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2274:       if (flag_draw || flag_contour) {
2275:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Explicit Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2276:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2277:       } else vdraw = NULL;
2278:       PetscViewerASCIIPrintf(vstdout,"Explicit %s\n",flag_operator ? "Jacobian" : "preconditioning Jacobian");
2279:       if (flag) {MatView(Bexp,vstdout);}
2280:       if (vdraw) {MatView(Bexp,vdraw);}
2281:       PetscViewerASCIIPrintf(vstdout,"Finite difference Jacobian\n");
2282:       if (flag) {MatView(FDexp,vstdout);}
2283:       if (vdraw) {MatView(FDexp,vdraw);}
2284:       MatAYPX(FDexp,-1.0,Bexp,SAME_NONZERO_PATTERN);
2285:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian\n");
2286:       if (flag) {MatView(FDexp,vstdout);}
2287:       if (vdraw) {              /* Always use contour for the difference */
2288:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2289:         MatView(FDexp,vdraw);
2290:         PetscViewerPopFormat(vdraw);
2291:       }
2292:       if (flag_contour) {PetscViewerPopFormat(vdraw);}
2293:       PetscViewerDestroy(&vdraw);
2294:       MatDestroy(&Bexp_mine);
2295:       MatDestroy(&FDexp);
2296:     }
2297:   }
2298:   {
2299:     PetscBool flag = PETSC_FALSE,flag_display = PETSC_FALSE,flag_draw = PETSC_FALSE,flag_contour = PETSC_FALSE,flag_threshold = PETSC_FALSE;
2300:     PetscReal threshold_atol = PETSC_SQRT_MACHINE_EPSILON,threshold_rtol = 10*PETSC_SQRT_MACHINE_EPSILON;
2301:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring",&flag,NULL);
2302:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_display",&flag_display,NULL);
2303:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_draw",&flag_draw,NULL);
2304:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_draw_contour",&flag_contour,NULL);
2305:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold",&flag_threshold,NULL);
2306:     PetscOptionsGetReal(((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_rtol",&threshold_rtol,NULL);
2307:     PetscOptionsGetReal(((PetscObject)snes)->prefix,"-snes_compare_coloring_threshold_atol",&threshold_atol,NULL);
2308:     if (flag || flag_display || flag_draw || flag_contour || flag_threshold) {
2309:       Mat            Bfd;
2310:       PetscViewer    vdraw,vstdout;
2311:       MatColoring    coloring;
2312:       ISColoring     iscoloring;
2313:       MatFDColoring  matfdcoloring;
2314:       PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2315:       void           *funcctx;
2316:       PetscReal      norm1,norm2,normmax;

2318:       MatDuplicate(B,MAT_DO_NOT_COPY_VALUES,&Bfd);
2319:       MatColoringCreate(Bfd,&coloring);
2320:       MatColoringSetType(coloring,MATCOLORINGSL);
2321:       MatColoringSetFromOptions(coloring);
2322:       MatColoringApply(coloring,&iscoloring);
2323:       MatColoringDestroy(&coloring);
2324:       MatFDColoringCreate(Bfd,iscoloring,&matfdcoloring);
2325:       MatFDColoringSetFromOptions(matfdcoloring);
2326:       MatFDColoringSetUp(Bfd,iscoloring,matfdcoloring);
2327:       ISColoringDestroy(&iscoloring);

2329:       /* This method of getting the function is currently unreliable since it doesn't work for DM local functions. */
2330:       SNESGetFunction(snes,NULL,&func,&funcctx);
2331:       MatFDColoringSetFunction(matfdcoloring,(PetscErrorCode (*)(void))func,funcctx);
2332:       PetscObjectSetOptionsPrefix((PetscObject)matfdcoloring,((PetscObject)snes)->prefix);
2333:       PetscObjectAppendOptionsPrefix((PetscObject)matfdcoloring,"coloring_");
2334:       MatFDColoringSetFromOptions(matfdcoloring);
2335:       MatFDColoringApply(Bfd,matfdcoloring,X,snes);
2336:       MatFDColoringDestroy(&matfdcoloring);

2338:       PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)snes),&vstdout);
2339:       if (flag_draw || flag_contour) {
2340:         PetscViewerDrawOpen(PetscObjectComm((PetscObject)snes),0,"Colored Jacobians",PETSC_DECIDE,PETSC_DECIDE,300,300,&vdraw);
2341:         if (flag_contour) {PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);}
2342:       } else vdraw = NULL;
2343:       PetscViewerASCIIPrintf(vstdout,"Explicit preconditioning Jacobian\n");
2344:       if (flag_display) {MatView(B,vstdout);}
2345:       if (vdraw) {MatView(B,vdraw);}
2346:       PetscViewerASCIIPrintf(vstdout,"Colored Finite difference Jacobian\n");
2347:       if (flag_display) {MatView(Bfd,vstdout);}
2348:       if (vdraw) {MatView(Bfd,vdraw);}
2349:       MatAYPX(Bfd,-1.0,B,SAME_NONZERO_PATTERN);
2350:       MatNorm(Bfd,NORM_1,&norm1);
2351:       MatNorm(Bfd,NORM_FROBENIUS,&norm2);
2352:       MatNorm(Bfd,NORM_MAX,&normmax);
2353:       PetscViewerASCIIPrintf(vstdout,"User-provided matrix minus finite difference Jacobian, norm1=%g normFrob=%g normmax=%g\n",(double)norm1,(double)norm2,(double)normmax);
2354:       if (flag_display) {MatView(Bfd,vstdout);}
2355:       if (vdraw) {              /* Always use contour for the difference */
2356:         PetscViewerPushFormat(vdraw,PETSC_VIEWER_DRAW_CONTOUR);
2357:         MatView(Bfd,vdraw);
2358:         PetscViewerPopFormat(vdraw);
2359:       }
2360:       if (flag_contour) {PetscViewerPopFormat(vdraw);}

2362:       if (flag_threshold) {
2363:         PetscInt bs,rstart,rend,i;
2364:         MatGetBlockSize(B,&bs);
2365:         MatGetOwnershipRange(B,&rstart,&rend);
2366:         for (i=rstart; i<rend; i++) {
2367:           const PetscScalar *ba,*ca;
2368:           const PetscInt    *bj,*cj;
2369:           PetscInt          bn,cn,j,maxentrycol = -1,maxdiffcol = -1,maxrdiffcol = -1;
2370:           PetscReal         maxentry = 0,maxdiff = 0,maxrdiff = 0;
2371:           MatGetRow(B,i,&bn,&bj,&ba);
2372:           MatGetRow(Bfd,i,&cn,&cj,&ca);
2373:           if (bn != cn) SETERRQ(((PetscObject)A)->comm,PETSC_ERR_PLIB,"Unexpected different nonzero pattern in -snes_compare_coloring_threshold");
2374:           for (j=0; j<bn; j++) {
2375:             PetscReal rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2376:             if (PetscAbsScalar(ba[j]) > PetscAbs(maxentry)) {
2377:               maxentrycol = bj[j];
2378:               maxentry    = PetscRealPart(ba[j]);
2379:             }
2380:             if (PetscAbsScalar(ca[j]) > PetscAbs(maxdiff)) {
2381:               maxdiffcol = bj[j];
2382:               maxdiff    = PetscRealPart(ca[j]);
2383:             }
2384:             if (rdiff > maxrdiff) {
2385:               maxrdiffcol = bj[j];
2386:               maxrdiff    = rdiff;
2387:             }
2388:           }
2389:           if (maxrdiff > 1) {
2390:             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);
2391:             for (j=0; j<bn; j++) {
2392:               PetscReal rdiff;
2393:               rdiff = PetscAbsScalar(ca[j]) / (threshold_atol + threshold_rtol*PetscAbsScalar(ba[j]));
2394:               if (rdiff > 1) {
2395:                 PetscViewerASCIIPrintf(vstdout," (%D,%g:%g)",bj[j],(double)PetscRealPart(ba[j]),(double)PetscRealPart(ca[j]));
2396:               }
2397:             }
2398:             PetscViewerASCIIPrintf(vstdout,"\n",i,maxentry,maxdiff,maxrdiff);
2399:           }
2400:           MatRestoreRow(B,i,&bn,&bj,&ba);
2401:           MatRestoreRow(Bfd,i,&cn,&cj,&ca);
2402:         }
2403:       }
2404:       PetscViewerDestroy(&vdraw);
2405:       MatDestroy(&Bfd);
2406:     }
2407:   }
2408:   return(0);
2409: }

2411: /*MC
2412:     SNESJacobianFunction - Function used to convey the nonlinear Jacobian of the function to be solved by SNES

2414:      Synopsis:
2415:      #include "petscsnes.h"
2416:      PetscErrorCode SNESJacobianFunction(SNES snes,Vec x,Mat Amat,Mat Pmat,void *ctx);

2418: +  x - input vector
2419: .  Amat - the matrix that defines the (approximate) Jacobian
2420: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2421: -  ctx - [optional] user-defined Jacobian context

2423:    Level: intermediate

2425: .seealso:   SNESSetFunction(), SNESGetFunction(), SNESSetJacobian(), SNESGetJacobian()
2426: M*/

2430: /*@C
2431:    SNESSetJacobian - Sets the function to compute Jacobian as well as the
2432:    location to store the matrix.

2434:    Logically Collective on SNES and Mat

2436:    Input Parameters:
2437: +  snes - the SNES context
2438: .  Amat - the matrix that defines the (approximate) Jacobian
2439: .  Pmat - the matrix to be used in constructing the preconditioner, usually the same as Amat.
2440: .  J - Jacobian evaluation routine (if NULL then SNES retains any previously set value), see SNESJacobianFunction for details
2441: -  ctx - [optional] user-defined context for private data for the
2442:          Jacobian evaluation routine (may be NULL) (if NULL then SNES retains any previously set value)

2444:    Notes:
2445:    If the Amat matrix and Pmat matrix are different you must call MatAssemblyBegin/End() on
2446:    each matrix.

2448:    If using SNESComputeJacobianDefaultColor() to assemble a Jacobian, the ctx argument
2449:    must be a MatFDColoring.

2451:    Other defect-correction schemes can be used by computing a different matrix in place of the Jacobian.  One common
2452:    example is to use the "Picard linearization" which only differentiates through the highest order parts of each term.

2454:    Level: beginner

2456: .keywords: SNES, nonlinear, set, Jacobian, matrix

2458: .seealso: KSPSetOperators(), SNESSetFunction(), MatMFFDComputeJacobian(), SNESComputeJacobianDefaultColor(), MatStructure, J, 
2459:           SNESSetPicard(), SNESJacobianFunction
2460: @*/
2461: PetscErrorCode  SNESSetJacobian(SNES snes,Mat Amat,Mat Pmat,PetscErrorCode (*J)(SNES,Vec,Mat,Mat,void*),void *ctx)
2462: {
2464:   DM             dm;

2472:   SNESGetDM(snes,&dm);
2473:   DMSNESSetJacobian(dm,J,ctx);
2474:   if (Amat) {
2475:     PetscObjectReference((PetscObject)Amat);
2476:     MatDestroy(&snes->jacobian);

2478:     snes->jacobian = Amat;
2479:   }
2480:   if (Pmat) {
2481:     PetscObjectReference((PetscObject)Pmat);
2482:     MatDestroy(&snes->jacobian_pre);

2484:     snes->jacobian_pre = Pmat;
2485:   }
2486:   return(0);
2487: }

2491: /*@C
2492:    SNESGetJacobian - Returns the Jacobian matrix and optionally the user
2493:    provided context for evaluating the Jacobian.

2495:    Not Collective, but Mat object will be parallel if SNES object is

2497:    Input Parameter:
2498: .  snes - the nonlinear solver context

2500:    Output Parameters:
2501: +  Amat - location to stash (approximate) Jacobian matrix (or NULL)
2502: .  Pmat - location to stash matrix used to compute the preconditioner (or NULL)
2503: .  J - location to put Jacobian function (or NULL), see SNESJacobianFunction for details on its calling sequence
2504: -  ctx - location to stash Jacobian ctx (or NULL)

2506:    Level: advanced

2508: .seealso: SNESSetJacobian(), SNESComputeJacobian(), SNESJacobianFunction, SNESGetFunction()
2509: @*/
2510: PetscErrorCode SNESGetJacobian(SNES snes,Mat *Amat,Mat *Pmat,PetscErrorCode (**J)(SNES,Vec,Mat,Mat,void*),void **ctx)
2511: {
2513:   DM             dm;
2514:   DMSNES         sdm;

2518:   if (Amat) *Amat = snes->jacobian;
2519:   if (Pmat) *Pmat = snes->jacobian_pre;
2520:   SNESGetDM(snes,&dm);
2521:   DMGetDMSNES(dm,&sdm);
2522:   if (J) *J = sdm->ops->computejacobian;
2523:   if (ctx) *ctx = sdm->jacobianctx;
2524:   return(0);
2525: }

2529: /*@
2530:    SNESSetUp - Sets up the internal data structures for the later use
2531:    of a nonlinear solver.

2533:    Collective on SNES

2535:    Input Parameters:
2536: .  snes - the SNES context

2538:    Notes:
2539:    For basic use of the SNES solvers the user need not explicitly call
2540:    SNESSetUp(), since these actions will automatically occur during
2541:    the call to SNESSolve().  However, if one wishes to control this
2542:    phase separately, SNESSetUp() should be called after SNESCreate()
2543:    and optional routines of the form SNESSetXXX(), but before SNESSolve().

2545:    Level: advanced

2547: .keywords: SNES, nonlinear, setup

2549: .seealso: SNESCreate(), SNESSolve(), SNESDestroy()
2550: @*/
2551: PetscErrorCode  SNESSetUp(SNES snes)
2552: {
2554:   DM             dm;
2555:   DMSNES         sdm;
2556:   SNESLineSearch linesearch, pclinesearch;
2557:   void           *lsprectx,*lspostctx;
2558:   PetscErrorCode (*precheck)(SNESLineSearch,Vec,Vec,PetscBool*,void*);
2559:   PetscErrorCode (*postcheck)(SNESLineSearch,Vec,Vec,Vec,PetscBool*,PetscBool*,void*);
2560:   PetscErrorCode (*func)(SNES,Vec,Vec,void*);
2561:   Vec            f,fpc;
2562:   void           *funcctx;
2563:   PetscErrorCode (*jac)(SNES,Vec,Mat,Mat,void*);
2564:   void           *jacctx,*appctx;
2565:   Mat            j,jpre;

2569:   if (snes->setupcalled) return(0);

2571:   if (!((PetscObject)snes)->type_name) {
2572:     SNESSetType(snes,SNESNEWTONLS);
2573:   }

2575:   SNESGetFunction(snes,&snes->vec_func,NULL,NULL);

2577:   SNESGetDM(snes,&dm);
2578:   DMGetDMSNES(dm,&sdm);
2579:   if (!sdm->ops->computefunction) SETERRQ(PetscObjectComm((PetscObject)dm),PETSC_ERR_ARG_WRONGSTATE,"Function never provided to SNES object");
2580:   if (!sdm->ops->computejacobian) {
2581:     DMSNESSetJacobian(dm,SNESComputeJacobianDefaultColor,NULL);
2582:   }
2583:   if (!snes->vec_func) {
2584:     DMCreateGlobalVector(dm,&snes->vec_func);
2585:   }

2587:   if (!snes->ksp) {
2588:     SNESGetKSP(snes, &snes->ksp);
2589:   }

2591:   if (!snes->linesearch) {
2592:     SNESGetLineSearch(snes, &snes->linesearch);
2593:   }
2594:   SNESLineSearchSetFunction(snes->linesearch,SNESComputeFunction);

2596:   if (snes->pc && (snes->pcside == PC_LEFT)) {
2597:     snes->mf          = PETSC_TRUE;
2598:     snes->mf_operator = PETSC_FALSE;
2599:   }

2601:   if (snes->pc) {
2602:     /* copy the DM over */
2603:     SNESGetDM(snes,&dm);
2604:     SNESSetDM(snes->pc,dm);

2606:     SNESGetFunction(snes,&f,&func,&funcctx);
2607:     VecDuplicate(f,&fpc);
2608:     SNESSetFunction(snes->pc,fpc,func,funcctx);
2609:     SNESGetJacobian(snes,&j,&jpre,&jac,&jacctx);
2610:     SNESSetJacobian(snes->pc,j,jpre,jac,jacctx);
2611:     SNESGetApplicationContext(snes,&appctx);
2612:     SNESSetApplicationContext(snes->pc,appctx);
2613:     VecDestroy(&fpc);

2615:     /* copy the function pointers over */
2616:     PetscObjectCopyFortranFunctionPointers((PetscObject)snes,(PetscObject)snes->pc);

2618:     /* default to 1 iteration */
2619:     SNESSetTolerances(snes->pc,0.0,0.0,0.0,1,snes->pc->max_funcs);
2620:     if (snes->pcside==PC_RIGHT) {
2621:       SNESSetNormSchedule(snes->pc,SNES_NORM_FINAL_ONLY);
2622:     } else {
2623:       SNESSetNormSchedule(snes->pc,SNES_NORM_NONE);
2624:     }
2625:     SNESSetFromOptions(snes->pc);

2627:     /* copy the line search context over */
2628:     SNESGetLineSearch(snes,&linesearch);
2629:     SNESGetLineSearch(snes->pc,&pclinesearch);
2630:     SNESLineSearchGetPreCheck(linesearch,&precheck,&lsprectx);
2631:     SNESLineSearchGetPostCheck(linesearch,&postcheck,&lspostctx);
2632:     SNESLineSearchSetPreCheck(pclinesearch,precheck,lsprectx);
2633:     SNESLineSearchSetPostCheck(pclinesearch,postcheck,lspostctx);
2634:     PetscObjectCopyFortranFunctionPointers((PetscObject)linesearch, (PetscObject)pclinesearch);
2635:   }
2636:   if (snes->mf) {
2637:     SNESSetUpMatrixFree_Private(snes, snes->mf_operator, snes->mf_version);
2638:   }
2639:   if (snes->ops->usercompute && !snes->user) {
2640:     (*snes->ops->usercompute)(snes,(void**)&snes->user);
2641:   }

2643:   snes->jac_iter = 0;
2644:   snes->pre_iter = 0;

2646:   if (snes->ops->setup) {
2647:     (*snes->ops->setup)(snes);
2648:   }

2650:   if (snes->pc && (snes->pcside == PC_LEFT)) {
2651:     if (snes->functype == SNES_FUNCTION_PRECONDITIONED) {
2652:       SNESGetLineSearch(snes,&linesearch);
2653:       SNESLineSearchSetFunction(linesearch,SNESComputeFunctionDefaultNPC);
2654:     }
2655:   }

2657:   snes->setupcalled = PETSC_TRUE;
2658:   return(0);
2659: }

2663: /*@
2664:    SNESReset - Resets a SNES context to the snessetupcalled = 0 state and removes any allocated Vecs and Mats

2666:    Collective on SNES

2668:    Input Parameter:
2669: .  snes - iterative context obtained from SNESCreate()

2671:    Level: intermediate

2673:    Notes: Also calls the application context destroy routine set with SNESSetComputeApplicationContext()

2675: .keywords: SNES, destroy

2677: .seealso: SNESCreate(), SNESSetUp(), SNESSolve()
2678: @*/
2679: PetscErrorCode  SNESReset(SNES snes)
2680: {

2685:   if (snes->ops->userdestroy && snes->user) {
2686:     (*snes->ops->userdestroy)((void**)&snes->user);
2687:     snes->user = NULL;
2688:   }
2689:   if (snes->pc) {
2690:     SNESReset(snes->pc);
2691:   }

2693:   if (snes->ops->reset) {
2694:     (*snes->ops->reset)(snes);
2695:   }
2696:   if (snes->ksp) {
2697:     KSPReset(snes->ksp);
2698:   }

2700:   if (snes->linesearch) {
2701:     SNESLineSearchReset(snes->linesearch);
2702:   }

2704:   VecDestroy(&snes->vec_rhs);
2705:   VecDestroy(&snes->vec_sol);
2706:   VecDestroy(&snes->vec_sol_update);
2707:   VecDestroy(&snes->vec_func);
2708:   MatDestroy(&snes->jacobian);
2709:   MatDestroy(&snes->jacobian_pre);
2710:   VecDestroyVecs(snes->nwork,&snes->work);
2711:   VecDestroyVecs(snes->nvwork,&snes->vwork);

2713:   snes->nwork       = snes->nvwork = 0;
2714:   snes->setupcalled = PETSC_FALSE;
2715:   return(0);
2716: }

2720: /*@
2721:    SNESDestroy - Destroys the nonlinear solver context that was created
2722:    with SNESCreate().

2724:    Collective on SNES

2726:    Input Parameter:
2727: .  snes - the SNES context

2729:    Level: beginner

2731: .keywords: SNES, nonlinear, destroy

2733: .seealso: SNESCreate(), SNESSolve()
2734: @*/
2735: PetscErrorCode  SNESDestroy(SNES *snes)
2736: {

2740:   if (!*snes) return(0);
2742:   if (--((PetscObject)(*snes))->refct > 0) {*snes = 0; return(0);}

2744:   SNESReset((*snes));
2745:   SNESDestroy(&(*snes)->pc);

2747:   /* if memory was published with SAWs then destroy it */
2748:   PetscObjectSAWsViewOff((PetscObject)*snes);
2749:   if ((*snes)->ops->destroy) {(*((*snes))->ops->destroy)((*snes));}

2751:   DMDestroy(&(*snes)->dm);
2752:   KSPDestroy(&(*snes)->ksp);
2753:   SNESLineSearchDestroy(&(*snes)->linesearch);

2755:   PetscFree((*snes)->kspconvctx);
2756:   if ((*snes)->ops->convergeddestroy) {
2757:     (*(*snes)->ops->convergeddestroy)((*snes)->cnvP);
2758:   }
2759:   if ((*snes)->conv_malloc) {
2760:     PetscFree((*snes)->conv_hist);
2761:     PetscFree((*snes)->conv_hist_its);
2762:   }
2763:   SNESMonitorCancel((*snes));
2764:   PetscHeaderDestroy(snes);
2765:   return(0);
2766: }

2768: /* ----------- Routines to set solver parameters ---------- */

2772: /*@
2773:    SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

2775:    Logically Collective on SNES

2777:    Input Parameters:
2778: +  snes - the SNES context
2779: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2780:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

2782:    Options Database Keys:
2783: .    -snes_lag_preconditioner <lag>

2785:    Notes:
2786:    The default is 1
2787:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
2788:    If  -1 is used before the very first nonlinear solve the preconditioner is still built because there is no previous preconditioner to use

2790:    Level: intermediate

2792: .keywords: SNES, nonlinear, set, convergence, tolerances

2794: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian()

2796: @*/
2797: PetscErrorCode  SNESSetLagPreconditioner(SNES snes,PetscInt lag)
2798: {
2801:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
2802:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
2804:   snes->lagpreconditioner = lag;
2805:   return(0);
2806: }

2810: /*@
2811:    SNESSetGridSequence - sets the number of steps of grid sequencing that SNES does

2813:    Logically Collective on SNES

2815:    Input Parameters:
2816: +  snes - the SNES context
2817: -  steps - the number of refinements to do, defaults to 0

2819:    Options Database Keys:
2820: .    -snes_grid_sequence <steps>

2822:    Level: intermediate

2824:    Notes:
2825:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

2827: .keywords: SNES, nonlinear, set, convergence, tolerances

2829: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetGridSequence()

2831: @*/
2832: PetscErrorCode  SNESSetGridSequence(SNES snes,PetscInt steps)
2833: {
2837:   snes->gridsequence = steps;
2838:   return(0);
2839: }

2843: /*@
2844:    SNESGetGridSequence - gets the number of steps of grid sequencing that SNES does

2846:    Logically Collective on SNES

2848:    Input Parameter:
2849: .  snes - the SNES context

2851:    Output Parameter:
2852: .  steps - the number of refinements to do, defaults to 0

2854:    Options Database Keys:
2855: .    -snes_grid_sequence <steps>

2857:    Level: intermediate

2859:    Notes:
2860:    Use SNESGetSolution() to extract the fine grid solution after grid sequencing.

2862: .keywords: SNES, nonlinear, set, convergence, tolerances

2864: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESSetGridSequence()

2866: @*/
2867: PetscErrorCode  SNESGetGridSequence(SNES snes,PetscInt *steps)
2868: {
2871:   *steps = snes->gridsequence;
2872:   return(0);
2873: }

2877: /*@
2878:    SNESGetLagPreconditioner - Indicates how often the preconditioner is rebuilt

2880:    Not Collective

2882:    Input Parameter:
2883: .  snes - the SNES context

2885:    Output Parameter:
2886: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2887:          the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that

2889:    Options Database Keys:
2890: .    -snes_lag_preconditioner <lag>

2892:    Notes:
2893:    The default is 1
2894:    The preconditioner is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

2896:    Level: intermediate

2898: .keywords: SNES, nonlinear, set, convergence, tolerances

2900: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagPreconditioner()

2902: @*/
2903: PetscErrorCode  SNESGetLagPreconditioner(SNES snes,PetscInt *lag)
2904: {
2907:   *lag = snes->lagpreconditioner;
2908:   return(0);
2909: }

2913: /*@
2914:    SNESSetLagJacobian - Determines when the Jacobian is rebuilt in the nonlinear solve. See SNESSetLagPreconditioner() for determining how
2915:      often the preconditioner is rebuilt.

2917:    Logically Collective on SNES

2919:    Input Parameters:
2920: +  snes - the SNES context
2921: -  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2922:          the Jacobian is built etc. -2 means rebuild at next chance but then never again

2924:    Options Database Keys:
2925: .    -snes_lag_jacobian <lag>

2927:    Notes:
2928:    The default is 1
2929:    The Jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1
2930:    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
2931:    at the next Newton step but never again (unless it is reset to another value)

2933:    Level: intermediate

2935: .keywords: SNES, nonlinear, set, convergence, tolerances

2937: .seealso: SNESSetTrustRegionTolerance(), SNESGetLagPreconditioner(), SNESSetLagPreconditioner(), SNESGetLagJacobian()

2939: @*/
2940: PetscErrorCode  SNESSetLagJacobian(SNES snes,PetscInt lag)
2941: {
2944:   if (lag < -2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag must be -2, -1, 1 or greater");
2945:   if (!lag) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Lag cannot be 0");
2947:   snes->lagjacobian = lag;
2948:   return(0);
2949: }

2953: /*@
2954:    SNESGetLagJacobian - Indicates how often the Jacobian is rebuilt. See SNESGetLagPreconditioner() to determine when the preconditioner is rebuilt

2956:    Not Collective

2958:    Input Parameter:
2959: .  snes - the SNES context

2961:    Output Parameter:
2962: .   lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
2963:          the Jacobian is built etc.

2965:    Options Database Keys:
2966: .    -snes_lag_jacobian <lag>

2968:    Notes:
2969:    The default is 1
2970:    The jacobian is ALWAYS built in the first iteration of a nonlinear solve unless lag is -1

2972:    Level: intermediate

2974: .keywords: SNES, nonlinear, set, convergence, tolerances

2976: .seealso: SNESSetTrustRegionTolerance(), SNESSetLagJacobian(), SNESSetLagPreconditioner(), SNESGetLagPreconditioner()

2978: @*/
2979: PetscErrorCode  SNESGetLagJacobian(SNES snes,PetscInt *lag)
2980: {
2983:   *lag = snes->lagjacobian;
2984:   return(0);
2985: }

2989: /*@
2990:    SNESSetLagJacobianPersists - Set whether or not the Jacobian lagging persists through multiple solves

2992:    Logically collective on SNES

2994:    Input Parameter:
2995: +  snes - the SNES context
2996: -   flg - jacobian lagging persists if true

2998:    Options Database Keys:
2999: .    -snes_lag_jacobian_persists <flg>

3001:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the Jacobian be stale by
3002:    several solves, and for implicit time-stepping, where Jacobian lagging in the inner nonlinear solve over several
3003:    timesteps may present huge efficiency gains.

3005:    Level: developer

3007: .keywords: SNES, nonlinear, lag

3009: .seealso: SNESSetLagPreconditionerPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3011: @*/
3012: PetscErrorCode  SNESSetLagJacobianPersists(SNES snes,PetscBool flg)
3013: {
3017:   snes->lagjac_persist = flg;
3018:   return(0);
3019: }

3023: /*@
3024:    SNESSetLagPreconditionerPersists - Set whether or not the preconditioner lagging persists through multiple solves

3026:    Logically Collective on SNES

3028:    Input Parameter:
3029: +  snes - the SNES context
3030: -   flg - preconditioner lagging persists if true

3032:    Options Database Keys:
3033: .    -snes_lag_jacobian_persists <flg>

3035:    Notes: This is useful both for nonlinear preconditioning, where it's appropriate to have the preconditioner be stale
3036:    by several solves, and for implicit time-stepping, where preconditioner lagging in the inner nonlinear solve over
3037:    several timesteps may present huge efficiency gains.

3039:    Level: developer

3041: .keywords: SNES, nonlinear, lag

3043: .seealso: SNESSetLagJacobianPersists(), SNESSetLagJacobian(), SNESGetLagJacobian(), SNESGetNPC()

3045: @*/
3046: PetscErrorCode  SNESSetLagPreconditionerPersists(SNES snes,PetscBool flg)
3047: {
3051:   snes->lagpre_persist = flg;
3052:   return(0);
3053: }

3057: /*@
3058:    SNESSetTolerances - Sets various parameters used in convergence tests.

3060:    Logically Collective on SNES

3062:    Input Parameters:
3063: +  snes - the SNES context
3064: .  abstol - absolute convergence tolerance
3065: .  rtol - relative convergence tolerance
3066: .  stol -  convergence tolerance in terms of the norm of the change in the solution between steps,  || delta x || < stol*|| x ||
3067: .  maxit - maximum number of iterations
3068: -  maxf - maximum number of function evaluations

3070:    Options Database Keys:
3071: +    -snes_atol <abstol> - Sets abstol
3072: .    -snes_rtol <rtol> - Sets rtol
3073: .    -snes_stol <stol> - Sets stol
3074: .    -snes_max_it <maxit> - Sets maxit
3075: -    -snes_max_funcs <maxf> - Sets maxf

3077:    Notes:
3078:    The default maximum number of iterations is 50.
3079:    The default maximum number of function evaluations is 1000.

3081:    Level: intermediate

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

3085: .seealso: SNESSetTrustRegionTolerance()
3086: @*/
3087: PetscErrorCode  SNESSetTolerances(SNES snes,PetscReal abstol,PetscReal rtol,PetscReal stol,PetscInt maxit,PetscInt maxf)
3088: {

3097:   if (abstol != PETSC_DEFAULT) {
3098:     if (abstol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Absolute tolerance %g must be non-negative",(double)abstol);
3099:     snes->abstol = abstol;
3100:   }
3101:   if (rtol != PETSC_DEFAULT) {
3102:     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);
3103:     snes->rtol = rtol;
3104:   }
3105:   if (stol != PETSC_DEFAULT) {
3106:     if (stol < 0.0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Step tolerance %g must be non-negative",(double)stol);
3107:     snes->stol = stol;
3108:   }
3109:   if (maxit != PETSC_DEFAULT) {
3110:     if (maxit < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of iterations %D must be non-negative",maxit);
3111:     snes->max_its = maxit;
3112:   }
3113:   if (maxf != PETSC_DEFAULT) {
3114:     if (maxf < 0) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_OUTOFRANGE,"Maximum number of function evaluations %D must be non-negative",maxf);
3115:     snes->max_funcs = maxf;
3116:   }
3117:   snes->tolerancesset = PETSC_TRUE;
3118:   return(0);
3119: }

3123: /*@
3124:    SNESGetTolerances - Gets various parameters used in convergence tests.

3126:    Not Collective

3128:    Input Parameters:
3129: +  snes - the SNES context
3130: .  atol - absolute convergence tolerance
3131: .  rtol - relative convergence tolerance
3132: .  stol -  convergence tolerance in terms of the norm
3133:            of the change in the solution between steps
3134: .  maxit - maximum number of iterations
3135: -  maxf - maximum number of function evaluations

3137:    Notes:
3138:    The user can specify NULL for any parameter that is not needed.

3140:    Level: intermediate

3142: .keywords: SNES, nonlinear, get, convergence, tolerances

3144: .seealso: SNESSetTolerances()
3145: @*/
3146: PetscErrorCode  SNESGetTolerances(SNES snes,PetscReal *atol,PetscReal *rtol,PetscReal *stol,PetscInt *maxit,PetscInt *maxf)
3147: {
3150:   if (atol)  *atol  = snes->abstol;
3151:   if (rtol)  *rtol  = snes->rtol;
3152:   if (stol)  *stol  = snes->stol;
3153:   if (maxit) *maxit = snes->max_its;
3154:   if (maxf)  *maxf  = snes->max_funcs;
3155:   return(0);
3156: }

3160: /*@
3161:    SNESSetTrustRegionTolerance - Sets the trust region parameter tolerance.

3163:    Logically Collective on SNES

3165:    Input Parameters:
3166: +  snes - the SNES context
3167: -  tol - tolerance

3169:    Options Database Key:
3170: .  -snes_trtol <tol> - Sets tol

3172:    Level: intermediate

3174: .keywords: SNES, nonlinear, set, trust region, tolerance

3176: .seealso: SNESSetTolerances()
3177: @*/
3178: PetscErrorCode  SNESSetTrustRegionTolerance(SNES snes,PetscReal tol)
3179: {
3183:   snes->deltatol = tol;
3184:   return(0);
3185: }

3187: /*
3188:    Duplicate the lg monitors for SNES from KSP; for some reason with
3189:    dynamic libraries things don't work under Sun4 if we just use
3190:    macros instead of functions
3191: */
3194: PetscErrorCode  SNESMonitorLGResidualNorm(SNES snes,PetscInt it,PetscReal norm,PetscObject *objs)
3195: {

3200:   KSPMonitorLGResidualNorm((KSP)snes,it,norm,objs);
3201:   return(0);
3202: }

3206: PetscErrorCode  SNESMonitorLGCreate(const char host[],const char label[],int x,int y,int m,int n,PetscObject **draw)
3207: {

3211:   KSPMonitorLGResidualNormCreate(host,label,x,y,m,n,draw);
3212:   return(0);
3213: }

3217: PetscErrorCode  SNESMonitorLGDestroy(PetscObject **objs)
3218: {

3222:   KSPMonitorLGResidualNormDestroy(objs);
3223:   return(0);
3224: }

3226: extern PetscErrorCode  SNESMonitorRange_Private(SNES,PetscInt,PetscReal*);
3229: PetscErrorCode  SNESMonitorLGRange(SNES snes,PetscInt n,PetscReal rnorm,void *monctx)
3230: {
3231:   PetscDrawLG      lg;
3232:   PetscErrorCode   ierr;
3233:   PetscReal        x,y,per;
3234:   PetscViewer      v = (PetscViewer)monctx;
3235:   static PetscReal prev; /* should be in the context */
3236:   PetscDraw        draw;

3239:   PetscViewerDrawGetDrawLG(v,0,&lg);
3240:   if (!n) {PetscDrawLGReset(lg);}
3241:   PetscDrawLGGetDraw(lg,&draw);
3242:   PetscDrawSetTitle(draw,"Residual norm");
3243:   x    = (PetscReal)n;
3244:   if (rnorm > 0.0) y = PetscLog10Real(rnorm);
3245:   else y = -15.0;
3246:   PetscDrawLGAddPoint(lg,&x,&y);
3247:   if (n < 20 || !(n % 5)) {
3248:     PetscDrawLGDraw(lg);
3249:   }

3251:   PetscViewerDrawGetDrawLG(v,1,&lg);
3252:   if (!n) {PetscDrawLGReset(lg);}
3253:   PetscDrawLGGetDraw(lg,&draw);
3254:   PetscDrawSetTitle(draw,"% elemts > .2*max elemt");
3255:    SNESMonitorRange_Private(snes,n,&per);
3256:   x    = (PetscReal)n;
3257:   y    = 100.0*per;
3258:   PetscDrawLGAddPoint(lg,&x,&y);
3259:   if (n < 20 || !(n % 5)) {
3260:     PetscDrawLGDraw(lg);
3261:   }

3263:   PetscViewerDrawGetDrawLG(v,2,&lg);
3264:   if (!n) {prev = rnorm;PetscDrawLGReset(lg);}
3265:   PetscDrawLGGetDraw(lg,&draw);
3266:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm");
3267:   x    = (PetscReal)n;
3268:   y    = (prev - rnorm)/prev;
3269:   PetscDrawLGAddPoint(lg,&x,&y);
3270:   if (n < 20 || !(n % 5)) {
3271:     PetscDrawLGDraw(lg);
3272:   }

3274:   PetscViewerDrawGetDrawLG(v,3,&lg);
3275:   if (!n) {PetscDrawLGReset(lg);}
3276:   PetscDrawLGGetDraw(lg,&draw);
3277:   PetscDrawSetTitle(draw,"(norm -oldnorm)/oldnorm*(% > .2 max)");
3278:   x    = (PetscReal)n;
3279:   y    = (prev - rnorm)/(prev*per);
3280:   if (n > 2) { /*skip initial crazy value */
3281:     PetscDrawLGAddPoint(lg,&x,&y);
3282:   }
3283:   if (n < 20 || !(n % 5)) {
3284:     PetscDrawLGDraw(lg);
3285:   }
3286:   prev = rnorm;
3287:   return(0);
3288: }

3292: /*@
3293:    SNESMonitor - runs the user provided monitor routines, if they exist

3295:    Collective on SNES

3297:    Input Parameters:
3298: +  snes - nonlinear solver context obtained from SNESCreate()
3299: .  iter - iteration number
3300: -  rnorm - relative norm of the residual

3302:    Notes:
3303:    This routine is called by the SNES implementations.
3304:    It does not typically need to be called by the user.

3306:    Level: developer

3308: .seealso: SNESMonitorSet()
3309: @*/
3310: PetscErrorCode  SNESMonitor(SNES snes,PetscInt iter,PetscReal rnorm)
3311: {
3313:   PetscInt       i,n = snes->numbermonitors;

3316:   VecLockPush(snes->vec_sol);
3317:   for (i=0; i<n; i++) {
3318:     (*snes->monitor[i])(snes,iter,rnorm,snes->monitorcontext[i]);
3319:   }
3320:   VecLockPop(snes->vec_sol);
3321:   return(0);
3322: }

3324: /* ------------ Routines to set performance monitoring options ----------- */

3326: /*MC
3327:     SNESMonitorFunction - functional form passed to SNESMonitorSet() to monitor convergence of nonlinear solver

3329:      Synopsis:
3330:      #include <petscsnes.h>
3331: $    PetscErrorCode SNESMonitorFunction(SNES snes,PetscInt its, PetscReal norm,void *mctx)

3333: +    snes - the SNES context
3334: .    its - iteration number
3335: .    norm - 2-norm function value (may be estimated)
3336: -    mctx - [optional] monitoring context

3338:    Level: advanced

3340: .seealso:   SNESMonitorSet(), SNESMonitorGet()
3341: M*/

3345: /*@C
3346:    SNESMonitorSet - Sets an ADDITIONAL function that is to be used at every
3347:    iteration of the nonlinear solver to display the iteration's
3348:    progress.

3350:    Logically Collective on SNES

3352:    Input Parameters:
3353: +  snes - the SNES context
3354: .  f - the monitor function, see SNESMonitorFunction for the calling sequence
3355: .  mctx - [optional] user-defined context for private data for the
3356:           monitor routine (use NULL if no context is desired)
3357: -  monitordestroy - [optional] routine that frees monitor context
3358:           (may be NULL)

3360:    Options Database Keys:
3361: +    -snes_monitor        - sets SNESMonitorDefault()
3362: .    -snes_monitor_lg_residualnorm    - sets line graph monitor,
3363:                             uses SNESMonitorLGCreate()
3364: -    -snes_monitor_cancel - cancels all monitors that have
3365:                             been hardwired into a code by
3366:                             calls to SNESMonitorSet(), but
3367:                             does not cancel those set via
3368:                             the options database.

3370:    Notes:
3371:    Several different monitoring routines may be set by calling
3372:    SNESMonitorSet() multiple times; all will be called in the
3373:    order in which they were set.

3375:    Fortran notes: Only a single monitor function can be set for each SNES object

3377:    Level: intermediate

3379: .keywords: SNES, nonlinear, set, monitor

3381: .seealso: SNESMonitorDefault(), SNESMonitorCancel(), SNESMonitorFunction
3382: @*/
3383: PetscErrorCode  SNESMonitorSet(SNES snes,PetscErrorCode (*f)(SNES,PetscInt,PetscReal,void*),void *mctx,PetscErrorCode (*monitordestroy)(void**))
3384: {
3385:   PetscInt       i;

3390:   if (snes->numbermonitors >= MAXSNESMONITORS) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Too many monitors set");
3391:   for (i=0; i<snes->numbermonitors;i++) {
3392:     if (f == snes->monitor[i] && monitordestroy == snes->monitordestroy[i] && mctx == snes->monitorcontext[i]) {
3393:       if (monitordestroy) {
3394:         (*monitordestroy)(&mctx);
3395:       }
3396:       return(0);
3397:     }
3398:   }
3399:   snes->monitor[snes->numbermonitors]          = f;
3400:   snes->monitordestroy[snes->numbermonitors]   = monitordestroy;
3401:   snes->monitorcontext[snes->numbermonitors++] = (void*)mctx;
3402:   return(0);
3403: }

3407: /*@
3408:    SNESMonitorCancel - Clears all the monitor functions for a SNES object.

3410:    Logically Collective on SNES

3412:    Input Parameters:
3413: .  snes - the SNES context

3415:    Options Database Key:
3416: .  -snes_monitor_cancel - cancels all monitors that have been hardwired
3417:     into a code by calls to SNESMonitorSet(), but does not cancel those
3418:     set via the options database

3420:    Notes:
3421:    There is no way to clear one specific monitor from a SNES object.

3423:    Level: intermediate

3425: .keywords: SNES, nonlinear, set, monitor

3427: .seealso: SNESMonitorDefault(), SNESMonitorSet()
3428: @*/
3429: PetscErrorCode  SNESMonitorCancel(SNES snes)
3430: {
3432:   PetscInt       i;

3436:   for (i=0; i<snes->numbermonitors; i++) {
3437:     if (snes->monitordestroy[i]) {
3438:       (*snes->monitordestroy[i])(&snes->monitorcontext[i]);
3439:     }
3440:   }
3441:   snes->numbermonitors = 0;
3442:   return(0);
3443: }

3445: /*MC
3446:     SNESConvergenceTestFunction - functional form used for testing of convergence of nonlinear solver

3448:      Synopsis:
3449:      #include <petscsnes.h>
3450: $     PetscErrorCode SNESConvergenceTest(SNES snes,PetscInt it,PetscReal xnorm,PetscReal gnorm,PetscReal f,SNESConvergedReason *reason,void *cctx)

3452: +    snes - the SNES context
3453: .    it - current iteration (0 is the first and is before any Newton step)
3454: .    cctx - [optional] convergence context
3455: .    reason - reason for convergence/divergence
3456: .    xnorm - 2-norm of current iterate
3457: .    gnorm - 2-norm of current step
3458: -    f - 2-norm of function

3460:    Level: intermediate

3462: .seealso:   SNESSetConvergenceTest(), SNESGetConvergenceTest()
3463: M*/

3467: /*@C
3468:    SNESSetConvergenceTest - Sets the function that is to be used
3469:    to test for convergence of the nonlinear iterative solution.

3471:    Logically Collective on SNES

3473:    Input Parameters:
3474: +  snes - the SNES context
3475: .  SNESConvergenceTestFunction - routine to test for convergence
3476: .  cctx - [optional] context for private data for the convergence routine  (may be NULL)
3477: -  destroy - [optional] destructor for the context (may be NULL; NULL_FUNCTION in Fortran)

3479:    Level: advanced

3481: .keywords: SNES, nonlinear, set, convergence, test

3483: .seealso: SNESConvergedDefault(), SNESConvergedSkip(), SNESConvergenceTestFunction
3484: @*/
3485: PetscErrorCode  SNESSetConvergenceTest(SNES snes,PetscErrorCode (*SNESConvergenceTestFunction)(SNES,PetscInt,PetscReal,PetscReal,PetscReal,SNESConvergedReason*,void*),void *cctx,PetscErrorCode (*destroy)(void*))
3486: {

3491:   if (!SNESConvergenceTestFunction) SNESConvergenceTestFunction = SNESConvergedSkip;
3492:   if (snes->ops->convergeddestroy) {
3493:     (*snes->ops->convergeddestroy)(snes->cnvP);
3494:   }
3495:   snes->ops->converged        = SNESConvergenceTestFunction;
3496:   snes->ops->convergeddestroy = destroy;
3497:   snes->cnvP                  = cctx;
3498:   return(0);
3499: }

3503: /*@
3504:    SNESGetConvergedReason - Gets the reason the SNES iteration was stopped.

3506:    Not Collective

3508:    Input Parameter:
3509: .  snes - the SNES context

3511:    Output Parameter:
3512: .  reason - negative value indicates diverged, positive value converged, see SNESConvergedReason or the
3513:             manual pages for the individual convergence tests for complete lists

3515:    Level: intermediate

3517:    Notes: Can only be called after the call the SNESSolve() is complete.

3519: .keywords: SNES, nonlinear, set, convergence, test

3521: .seealso: SNESSetConvergenceTest(), SNESConvergedReason
3522: @*/
3523: PetscErrorCode  SNESGetConvergedReason(SNES snes,SNESConvergedReason *reason)
3524: {
3528:   *reason = snes->reason;
3529:   return(0);
3530: }

3534: /*@
3535:    SNESSetConvergenceHistory - Sets the array used to hold the convergence history.

3537:    Logically Collective on SNES

3539:    Input Parameters:
3540: +  snes - iterative context obtained from SNESCreate()
3541: .  a   - array to hold history, this array will contain the function norms computed at each step
3542: .  its - integer array holds the number of linear iterations for each solve.
3543: .  na  - size of a and its
3544: -  reset - PETSC_TRUE indicates each new nonlinear solve resets the history counter to zero,
3545:            else it continues storing new values for new nonlinear solves after the old ones

3547:    Notes:
3548:    If 'a' and 'its' are NULL then space is allocated for the history. If 'na' PETSC_DECIDE or PETSC_DEFAULT then a
3549:    default array of length 10000 is allocated.

3551:    This routine is useful, e.g., when running a code for purposes
3552:    of accurate performance monitoring, when no I/O should be done
3553:    during the section of code that is being timed.

3555:    Level: intermediate

3557: .keywords: SNES, set, convergence, history

3559: .seealso: SNESGetConvergenceHistory()

3561: @*/
3562: PetscErrorCode  SNESSetConvergenceHistory(SNES snes,PetscReal a[],PetscInt its[],PetscInt na,PetscBool reset)
3563: {

3570:   if (!a) {
3571:     if (na == PETSC_DECIDE || na == PETSC_DEFAULT) na = 1000;
3572:     PetscCalloc1(na,&a);
3573:     PetscCalloc1(na,&its);

3575:     snes->conv_malloc = PETSC_TRUE;
3576:   }
3577:   snes->conv_hist       = a;
3578:   snes->conv_hist_its   = its;
3579:   snes->conv_hist_max   = na;
3580:   snes->conv_hist_len   = 0;
3581:   snes->conv_hist_reset = reset;
3582:   return(0);
3583: }

3585: #if defined(PETSC_HAVE_MATLAB_ENGINE)
3586: #include <engine.h>   /* MATLAB include file */
3587: #include <mex.h>      /* MATLAB include file */

3591: PETSC_EXTERN mxArray *SNESGetConvergenceHistoryMatlab(SNES snes)
3592: {
3593:   mxArray   *mat;
3594:   PetscInt  i;
3595:   PetscReal *ar;

3598:   mat = mxCreateDoubleMatrix(snes->conv_hist_len,1,mxREAL);
3599:   ar  = (PetscReal*) mxGetData(mat);
3600:   for (i=0; i<snes->conv_hist_len; i++) ar[i] = snes->conv_hist[i];
3601:   PetscFunctionReturn(mat);
3602: }
3603: #endif

3607: /*@C
3608:    SNESGetConvergenceHistory - Gets the array used to hold the convergence history.

3610:    Not Collective

3612:    Input Parameter:
3613: .  snes - iterative context obtained from SNESCreate()

3615:    Output Parameters:
3616: .  a   - array to hold history
3617: .  its - integer array holds the number of linear iterations (or
3618:          negative if not converged) for each solve.
3619: -  na  - size of a and its

3621:    Notes:
3622:     The calling sequence for this routine in Fortran is
3623: $   call SNESGetConvergenceHistory(SNES snes, integer na, integer ierr)

3625:    This routine is useful, e.g., when running a code for purposes
3626:    of accurate performance monitoring, when no I/O should be done
3627:    during the section of code that is being timed.

3629:    Level: intermediate

3631: .keywords: SNES, get, convergence, history

3633: .seealso: SNESSetConvergencHistory()

3635: @*/
3636: PetscErrorCode  SNESGetConvergenceHistory(SNES snes,PetscReal *a[],PetscInt *its[],PetscInt *na)
3637: {
3640:   if (a)   *a   = snes->conv_hist;
3641:   if (its) *its = snes->conv_hist_its;
3642:   if (na)  *na  = snes->conv_hist_len;
3643:   return(0);
3644: }

3648: /*@C
3649:   SNESSetUpdate - Sets the general-purpose update function called
3650:   at the beginning of every iteration of the nonlinear solve. Specifically
3651:   it is called just before the Jacobian is "evaluated".

3653:   Logically Collective on SNES

3655:   Input Parameters:
3656: . snes - The nonlinear solver context
3657: . func - The function

3659:   Calling sequence of func:
3660: . func (SNES snes, PetscInt step);

3662: . step - The current step of the iteration

3664:   Level: advanced

3666:   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()
3667:         This is not used by most users.

3669: .keywords: SNES, update

3671: .seealso SNESSetJacobian(), SNESSolve()
3672: @*/
3673: PetscErrorCode  SNESSetUpdate(SNES snes, PetscErrorCode (*func)(SNES, PetscInt))
3674: {
3677:   snes->ops->update = func;
3678:   return(0);
3679: }

3683: /*
3684:    SNESScaleStep_Private - Scales a step so that its length is less than the
3685:    positive parameter delta.

3687:     Input Parameters:
3688: +   snes - the SNES context
3689: .   y - approximate solution of linear system
3690: .   fnorm - 2-norm of current function
3691: -   delta - trust region size

3693:     Output Parameters:
3694: +   gpnorm - predicted function norm at the new point, assuming local
3695:     linearization.  The value is zero if the step lies within the trust
3696:     region, and exceeds zero otherwise.
3697: -   ynorm - 2-norm of the step

3699:     Note:
3700:     For non-trust region methods such as SNESNEWTONLS, the parameter delta
3701:     is set to be the maximum allowable step size.

3703: .keywords: SNES, nonlinear, scale, step
3704: */
3705: PetscErrorCode SNESScaleStep_Private(SNES snes,Vec y,PetscReal *fnorm,PetscReal *delta,PetscReal *gpnorm,PetscReal *ynorm)
3706: {
3707:   PetscReal      nrm;
3708:   PetscScalar    cnorm;


3716:   VecNorm(y,NORM_2,&nrm);
3717:   if (nrm > *delta) {
3718:     nrm     = *delta/nrm;
3719:     *gpnorm = (1.0 - nrm)*(*fnorm);
3720:     cnorm   = nrm;
3721:     VecScale(y,cnorm);
3722:     *ynorm  = *delta;
3723:   } else {
3724:     *gpnorm = 0.0;
3725:     *ynorm  = nrm;
3726:   }
3727:   return(0);
3728: }

3732: /*@
3733:    SNESReasonView - Displays the reason a SNES solve converged or diverged to a viewer

3735:    Collective on SNES

3737:    Parameter:
3738: +  snes - iterative context obtained from SNESCreate()
3739: -  viewer - the viewer to display the reason


3742:    Options Database Keys:
3743: .  -snes_converged_reason - print reason for converged or diverged, also prints number of iterations

3745:    Level: beginner

3747: .keywords: SNES, solve, linear system

3749: .seealso: SNESCreate(), SNESSetUp(), SNESDestroy(), SNESSetTolerances(), SNESConvergedDefault()

3751: @*/
3752: PetscErrorCode  SNESReasonView(SNES snes,PetscViewer viewer)
3753: {
3755:   PetscBool      isAscii;

3758:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isAscii);
3759:   if (isAscii) {
3760:     PetscViewerASCIIAddTab(viewer,((PetscObject)snes)->tablevel);
3761:     if (snes->reason > 0) {
3762:       if (((PetscObject) snes)->prefix) {
3763:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve converged due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
3764:       } else {
3765:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve converged due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
3766:       }
3767:     } else {
3768:       if (((PetscObject) snes)->prefix) {
3769:         PetscViewerASCIIPrintf(viewer,"Nonlinear %s solve did not converge due to %s iterations %D\n",((PetscObject) snes)->prefix,SNESConvergedReasons[snes->reason],snes->iter);
3770:       } else {
3771:         PetscViewerASCIIPrintf(viewer,"Nonlinear solve did not converge due to %s iterations %D\n",SNESConvergedReasons[snes->reason],snes->iter);
3772:       }
3773:     }
3774:     PetscViewerASCIISubtractTab(viewer,((PetscObject)snes)->tablevel);
3775:   }
3776:   return(0);
3777: }

3781: /*@C
3782:   SNESReasonViewFromOptions - Processes command line options to determine if/how a SNESReason is to be viewed. 

3784:   Collective on SNES

3786:   Input Parameters:
3787: . snes   - the SNES object

3789:   Level: intermediate

3791: @*/
3792: PetscErrorCode SNESReasonViewFromOptions(SNES snes)
3793: {
3794:   PetscErrorCode    ierr;
3795:   PetscViewer       viewer;
3796:   PetscBool         flg;
3797:   static PetscBool  incall = PETSC_FALSE;
3798:   PetscViewerFormat format;

3801:   if (incall) return(0);
3802:   incall = PETSC_TRUE;
3803:   PetscOptionsGetViewer(PetscObjectComm((PetscObject)snes),((PetscObject)snes)->prefix,"-snes_converged_reason",&viewer,&format,&flg);
3804:   if (flg) {
3805:     PetscViewerPushFormat(viewer,format);
3806:     SNESReasonView(snes,viewer);
3807:     PetscViewerPopFormat(viewer);
3808:     PetscViewerDestroy(&viewer);
3809:   }
3810:   incall = PETSC_FALSE;
3811:   return(0);
3812: }

3816: /*@C
3817:    SNESSolve - Solves a nonlinear system F(x) = b.
3818:    Call SNESSolve() after calling SNESCreate() and optional routines of the form SNESSetXXX().

3820:    Collective on SNES

3822:    Input Parameters:
3823: +  snes - the SNES context
3824: .  b - the constant part of the equation F(x) = b, or NULL to use zero.
3825: -  x - the solution vector.

3827:    Notes:
3828:    The user should initialize the vector,x, with the initial guess
3829:    for the nonlinear solve prior to calling SNESSolve.  In particular,
3830:    to employ an initial guess of zero, the user should explicitly set
3831:    this vector to zero by calling VecSet().

3833:    Level: beginner

3835: .keywords: SNES, nonlinear, solve

3837: .seealso: SNESCreate(), SNESDestroy(), SNESSetFunction(), SNESSetJacobian(), SNESSetGridSequence(), SNESGetSolution()
3838: @*/
3839: PetscErrorCode  SNESSolve(SNES snes,Vec b,Vec x)
3840: {
3841:   PetscErrorCode    ierr;
3842:   PetscBool         flg;
3843:   PetscInt          grid;
3844:   Vec               xcreated = NULL;
3845:   DM                dm;


3854:   if (!x) {
3855:     SNESGetDM(snes,&dm);
3856:     DMCreateGlobalVector(dm,&xcreated);
3857:     x    = xcreated;
3858:   }
3859:   SNESViewFromOptions(snes,NULL,"-snes_view_pre");

3861:   for (grid=0; grid<snes->gridsequence; grid++) {PetscViewerASCIIPushTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));}
3862:   for (grid=0; grid<snes->gridsequence+1; grid++) {

3864:     /* set solution vector */
3865:     if (!grid) {PetscObjectReference((PetscObject)x);}
3866:     VecDestroy(&snes->vec_sol);
3867:     snes->vec_sol = x;
3868:     SNESGetDM(snes,&dm);

3870:     /* set affine vector if provided */
3871:     if (b) { PetscObjectReference((PetscObject)b); }
3872:     VecDestroy(&snes->vec_rhs);
3873:     snes->vec_rhs = b;

3875:     if (snes->vec_func == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be function vector");
3876:     if (snes->vec_rhs  == snes->vec_sol) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_IDN,"Solution vector cannot be right hand side vector");
3877:     if (!snes->vec_sol_update /* && snes->vec_sol */) {
3878:       VecDuplicate(snes->vec_sol,&snes->vec_sol_update);
3879:       PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->vec_sol_update);
3880:     }
3881:     DMShellSetGlobalVector(dm,snes->vec_sol);
3882:     SNESSetUp(snes);

3884:     if (!grid) {
3885:       if (snes->ops->computeinitialguess) {
3886:         (*snes->ops->computeinitialguess)(snes,snes->vec_sol,snes->initialguessP);
3887:       }
3888:     }

3890:     if (snes->conv_hist_reset) snes->conv_hist_len = 0;
3891:     if (snes->counters_reset) {snes->nfuncs = 0; snes->linear_its = 0; snes->numFailures = 0;}

3893:     PetscLogEventBegin(SNES_Solve,snes,0,0,0);
3894:     (*snes->ops->solve)(snes);
3895:     PetscLogEventEnd(SNES_Solve,snes,0,0,0);
3896:     if (!snes->reason) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal error, solver returned without setting converged reason");
3897:     snes->domainerror = PETSC_FALSE; /* clear the flag if it has been set */

3899:     if (snes->lagjac_persist) snes->jac_iter += snes->iter;
3900:     if (snes->lagpre_persist) snes->pre_iter += snes->iter;

3902:     flg  = PETSC_FALSE;
3903:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-snes_test_local_min",&flg,NULL);
3904:     if (flg && !PetscPreLoadingOn) { SNESTestLocalMin(snes); }
3905:     SNESReasonViewFromOptions(snes);

3907:     if (snes->errorifnotconverged && snes->reason < 0) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_NOT_CONVERGED,"SNESSolve has not converged");
3908:     if (grid <  snes->gridsequence) {
3909:       DM  fine;
3910:       Vec xnew;
3911:       Mat interp;

3913:       DMRefine(snes->dm,PetscObjectComm((PetscObject)snes),&fine);
3914:       if (!fine) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_INCOMP,"DMRefine() did not perform any refinement, cannot continue grid sequencing");
3915:       DMCreateInterpolation(snes->dm,fine,&interp,NULL);
3916:       DMCreateGlobalVector(fine,&xnew);
3917:       MatInterpolate(interp,x,xnew);
3918:       DMInterpolate(snes->dm,interp,fine);
3919:       MatDestroy(&interp);
3920:       x    = xnew;

3922:       SNESReset(snes);
3923:       SNESSetDM(snes,fine);
3924:       DMDestroy(&fine);
3925:       PetscViewerASCIIPopTab(PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes)));
3926:     }
3927:   }
3928:   SNESViewFromOptions(snes,NULL,"-snes_view");
3929:   VecViewFromOptions(snes->vec_sol,(PetscObject)snes,"-snes_view_solution");

3931:   VecDestroy(&xcreated);
3932:   PetscObjectSAWsBlock((PetscObject)snes);
3933:   return(0);
3934: }

3936: /* --------- Internal routines for SNES Package --------- */

3940: /*@C
3941:    SNESSetType - Sets the method for the nonlinear solver.

3943:    Collective on SNES

3945:    Input Parameters:
3946: +  snes - the SNES context
3947: -  type - a known method

3949:    Options Database Key:
3950: .  -snes_type <type> - Sets the method; use -help for a list
3951:    of available methods (for instance, newtonls or newtontr)

3953:    Notes:
3954:    See "petsc/include/petscsnes.h" for available methods (for instance)
3955: +    SNESNEWTONLS - Newton's method with line search
3956:      (systems of nonlinear equations)
3957: .    SNESNEWTONTR - Newton's method with trust region
3958:      (systems of nonlinear equations)

3960:   Normally, it is best to use the SNESSetFromOptions() command and then
3961:   set the SNES solver type from the options database rather than by using
3962:   this routine.  Using the options database provides the user with
3963:   maximum flexibility in evaluating the many nonlinear solvers.
3964:   The SNESSetType() routine is provided for those situations where it
3965:   is necessary to set the nonlinear solver independently of the command
3966:   line or options database.  This might be the case, for example, when
3967:   the choice of solver changes during the execution of the program,
3968:   and the user's application is taking responsibility for choosing the
3969:   appropriate method.

3971:     Developer Notes: SNESRegister() adds a constructor for a new SNESType to SNESList, SNESSetType() locates
3972:     the constructor in that list and calls it to create the spexific object.

3974:   Level: intermediate

3976: .keywords: SNES, set, type

3978: .seealso: SNESType, SNESCreate(), SNESDestroy(), SNESGetType(), SNESSetFromOptions()

3980: @*/
3981: PetscErrorCode  SNESSetType(SNES snes,SNESType type)
3982: {
3983:   PetscErrorCode ierr,(*r)(SNES);
3984:   PetscBool      match;


3990:   PetscObjectTypeCompare((PetscObject)snes,type,&match);
3991:   if (match) return(0);

3993:    PetscFunctionListFind(SNESList,type,&r);
3994:   if (!r) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_UNKNOWN_TYPE,"Unable to find requested SNES type %s",type);
3995:   /* Destroy the previous private SNES context */
3996:   if (snes->ops->destroy) {
3997:     (*(snes)->ops->destroy)(snes);
3998:     snes->ops->destroy = NULL;
3999:   }
4000:   /* Reinitialize function pointers in SNESOps structure */
4001:   snes->ops->setup          = 0;
4002:   snes->ops->solve          = 0;
4003:   snes->ops->view           = 0;
4004:   snes->ops->setfromoptions = 0;
4005:   snes->ops->destroy        = 0;
4006:   /* Call the SNESCreate_XXX routine for this particular Nonlinear solver */
4007:   snes->setupcalled = PETSC_FALSE;

4009:   PetscObjectChangeTypeName((PetscObject)snes,type);
4010:   (*r)(snes);
4011:   return(0);
4012: }

4016: /*@C
4017:    SNESGetType - Gets the SNES method type and name (as a string).

4019:    Not Collective

4021:    Input Parameter:
4022: .  snes - nonlinear solver context

4024:    Output Parameter:
4025: .  type - SNES method (a character string)

4027:    Level: intermediate

4029: .keywords: SNES, nonlinear, get, type, name
4030: @*/
4031: PetscErrorCode  SNESGetType(SNES snes,SNESType *type)
4032: {
4036:   *type = ((PetscObject)snes)->type_name;
4037:   return(0);
4038: }

4042: /*@
4043:   SNESSetSolution - Sets the solution vector for use by the SNES routines.

4045:   Logically Collective on SNES and Vec

4047:   Input Parameters:
4048: + snes - the SNES context obtained from SNESCreate()
4049: - u    - the solution vector

4051:   Level: beginner

4053: .keywords: SNES, set, solution
4054: @*/
4055: PetscErrorCode SNESSetSolution(SNES snes, Vec u)
4056: {
4057:   DM             dm;

4063:   PetscObjectReference((PetscObject) u);
4064:   VecDestroy(&snes->vec_sol);

4066:   snes->vec_sol = u;

4068:   SNESGetDM(snes, &dm);
4069:   DMShellSetGlobalVector(dm, u);
4070:   return(0);
4071: }

4075: /*@
4076:    SNESGetSolution - Returns the vector where the approximate solution is
4077:    stored. This is the fine grid solution when using SNESSetGridSequence().

4079:    Not Collective, but Vec is parallel if SNES is parallel

4081:    Input Parameter:
4082: .  snes - the SNES context

4084:    Output Parameter:
4085: .  x - the solution

4087:    Level: intermediate

4089: .keywords: SNES, nonlinear, get, solution

4091: .seealso:  SNESGetSolutionUpdate(), SNESGetFunction()
4092: @*/
4093: PetscErrorCode  SNESGetSolution(SNES snes,Vec *x)
4094: {
4098:   *x = snes->vec_sol;
4099:   return(0);
4100: }

4104: /*@
4105:    SNESGetSolutionUpdate - Returns the vector where the solution update is
4106:    stored.

4108:    Not Collective, but Vec is parallel if SNES is parallel

4110:    Input Parameter:
4111: .  snes - the SNES context

4113:    Output Parameter:
4114: .  x - the solution update

4116:    Level: advanced

4118: .keywords: SNES, nonlinear, get, solution, update

4120: .seealso: SNESGetSolution(), SNESGetFunction()
4121: @*/
4122: PetscErrorCode  SNESGetSolutionUpdate(SNES snes,Vec *x)
4123: {
4127:   *x = snes->vec_sol_update;
4128:   return(0);
4129: }

4133: /*@C
4134:    SNESGetFunction - Returns the vector where the function is stored.

4136:    Not Collective, but Vec is parallel if SNES is parallel. Collective if Vec is requested, but has not been created yet.

4138:    Input Parameter:
4139: .  snes - the SNES context

4141:    Output Parameter:
4142: +  r - the vector that is used to store residuals (or NULL if you don't want it)
4143: .  f - the function (or NULL if you don't want it); see SNESFunction for calling sequence details
4144: -  ctx - the function context (or NULL if you don't want it)

4146:    Level: advanced

4148: .keywords: SNES, nonlinear, get, function

4150: .seealso: SNESSetFunction(), SNESGetSolution(), SNESFunction
4151: @*/
4152: PetscErrorCode  SNESGetFunction(SNES snes,Vec *r,PetscErrorCode (**f)(SNES,Vec,Vec,void*),void **ctx)
4153: {
4155:   DM             dm;

4159:   if (r) {
4160:     if (!snes->vec_func) {
4161:       if (snes->vec_rhs) {
4162:         VecDuplicate(snes->vec_rhs,&snes->vec_func);
4163:       } else if (snes->vec_sol) {
4164:         VecDuplicate(snes->vec_sol,&snes->vec_func);
4165:       } else if (snes->dm) {
4166:         DMCreateGlobalVector(snes->dm,&snes->vec_func);
4167:       }
4168:     }
4169:     *r = snes->vec_func;
4170:   }
4171:   SNESGetDM(snes,&dm);
4172:   DMSNESGetFunction(dm,f,ctx);
4173:   return(0);
4174: }

4176: /*@C
4177:    SNESGetNGS - Returns the NGS function and context.

4179:    Input Parameter:
4180: .  snes - the SNES context

4182:    Output Parameter:
4183: +  f - the function (or NULL) see SNESNGSFunction for details
4184: -  ctx    - the function context (or NULL)

4186:    Level: advanced

4188: .keywords: SNES, nonlinear, get, function

4190: .seealso: SNESSetNGS(), SNESGetFunction()
4191: @*/

4195: PetscErrorCode SNESGetNGS (SNES snes, PetscErrorCode (**f)(SNES, Vec, Vec, void*), void ** ctx)
4196: {
4198:   DM             dm;

4202:   SNESGetDM(snes,&dm);
4203:   DMSNESGetNGS(dm,f,ctx);
4204:   return(0);
4205: }

4209: /*@C
4210:    SNESSetOptionsPrefix - Sets the prefix used for searching for all
4211:    SNES options in the database.

4213:    Logically Collective on SNES

4215:    Input Parameter:
4216: +  snes - the SNES context
4217: -  prefix - the prefix to prepend to all option names

4219:    Notes:
4220:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4221:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4223:    Level: advanced

4225: .keywords: SNES, set, options, prefix, database

4227: .seealso: SNESSetFromOptions()
4228: @*/
4229: PetscErrorCode  SNESSetOptionsPrefix(SNES snes,const char prefix[])
4230: {

4235:   PetscObjectSetOptionsPrefix((PetscObject)snes,prefix);
4236:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4237:   if (snes->linesearch) {
4238:     SNESGetLineSearch(snes,&snes->linesearch);
4239:     PetscObjectSetOptionsPrefix((PetscObject)snes->linesearch,prefix);
4240:   }
4241:   KSPSetOptionsPrefix(snes->ksp,prefix);
4242:   return(0);
4243: }

4247: /*@C
4248:    SNESAppendOptionsPrefix - Appends to the prefix used for searching for all
4249:    SNES options in the database.

4251:    Logically Collective on SNES

4253:    Input Parameters:
4254: +  snes - the SNES context
4255: -  prefix - the prefix to prepend to all option names

4257:    Notes:
4258:    A hyphen (-) must NOT be given at the beginning of the prefix name.
4259:    The first character of all runtime options is AUTOMATICALLY the hyphen.

4261:    Level: advanced

4263: .keywords: SNES, append, options, prefix, database

4265: .seealso: SNESGetOptionsPrefix()
4266: @*/
4267: PetscErrorCode  SNESAppendOptionsPrefix(SNES snes,const char prefix[])
4268: {

4273:   PetscObjectAppendOptionsPrefix((PetscObject)snes,prefix);
4274:   if (!snes->ksp) {SNESGetKSP(snes,&snes->ksp);}
4275:   if (snes->linesearch) {
4276:     SNESGetLineSearch(snes,&snes->linesearch);
4277:     PetscObjectAppendOptionsPrefix((PetscObject)snes->linesearch,prefix);
4278:   }
4279:   KSPAppendOptionsPrefix(snes->ksp,prefix);
4280:   return(0);
4281: }

4285: /*@C
4286:    SNESGetOptionsPrefix - Sets the prefix used for searching for all
4287:    SNES options in the database.

4289:    Not Collective

4291:    Input Parameter:
4292: .  snes - the SNES context

4294:    Output Parameter:
4295: .  prefix - pointer to the prefix string used

4297:    Notes: On the fortran side, the user should pass in a string 'prefix' of
4298:    sufficient length to hold the prefix.

4300:    Level: advanced

4302: .keywords: SNES, get, options, prefix, database

4304: .seealso: SNESAppendOptionsPrefix()
4305: @*/
4306: PetscErrorCode  SNESGetOptionsPrefix(SNES snes,const char *prefix[])
4307: {

4312:   PetscObjectGetOptionsPrefix((PetscObject)snes,prefix);
4313:   return(0);
4314: }


4319: /*@C
4320:   SNESRegister - Adds a method to the nonlinear solver package.

4322:    Not collective

4324:    Input Parameters:
4325: +  name_solver - name of a new user-defined solver
4326: -  routine_create - routine to create method context

4328:    Notes:
4329:    SNESRegister() may be called multiple times to add several user-defined solvers.

4331:    Sample usage:
4332: .vb
4333:    SNESRegister("my_solver",MySolverCreate);
4334: .ve

4336:    Then, your solver can be chosen with the procedural interface via
4337: $     SNESSetType(snes,"my_solver")
4338:    or at runtime via the option
4339: $     -snes_type my_solver

4341:    Level: advanced

4343:     Note: If your function is not being put into a shared library then use SNESRegister() instead

4345: .keywords: SNES, nonlinear, register

4347: .seealso: SNESRegisterAll(), SNESRegisterDestroy()

4349:   Level: advanced
4350: @*/
4351: PetscErrorCode  SNESRegister(const char sname[],PetscErrorCode (*function)(SNES))
4352: {

4356:   PetscFunctionListAdd(&SNESList,sname,function);
4357:   return(0);
4358: }

4362: PetscErrorCode  SNESTestLocalMin(SNES snes)
4363: {
4365:   PetscInt       N,i,j;
4366:   Vec            u,uh,fh;
4367:   PetscScalar    value;
4368:   PetscReal      norm;

4371:   SNESGetSolution(snes,&u);
4372:   VecDuplicate(u,&uh);
4373:   VecDuplicate(u,&fh);

4375:   /* currently only works for sequential */
4376:   PetscPrintf(PETSC_COMM_WORLD,"Testing FormFunction() for local min\n");
4377:   VecGetSize(u,&N);
4378:   for (i=0; i<N; i++) {
4379:     VecCopy(u,uh);
4380:     PetscPrintf(PETSC_COMM_WORLD,"i = %D\n",i);
4381:     for (j=-10; j<11; j++) {
4382:       value = PetscSign(j)*PetscExpReal(PetscAbs(j)-10.0);
4383:       VecSetValue(uh,i,value,ADD_VALUES);
4384:       SNESComputeFunction(snes,uh,fh);
4385:       VecNorm(fh,NORM_2,&norm);
4386:       PetscPrintf(PETSC_COMM_WORLD,"       j norm %D %18.16e\n",j,norm);
4387:       value = -value;
4388:       VecSetValue(uh,i,value,ADD_VALUES);
4389:     }
4390:   }
4391:   VecDestroy(&uh);
4392:   VecDestroy(&fh);
4393:   return(0);
4394: }

4398: /*@
4399:    SNESKSPSetUseEW - Sets SNES use Eisenstat-Walker method for
4400:    computing relative tolerance for linear solvers within an inexact
4401:    Newton method.

4403:    Logically Collective on SNES

4405:    Input Parameters:
4406: +  snes - SNES context
4407: -  flag - PETSC_TRUE or PETSC_FALSE

4409:     Options Database:
4410: +  -snes_ksp_ew - use Eisenstat-Walker method for determining linear system convergence
4411: .  -snes_ksp_ew_version ver - version of  Eisenstat-Walker method
4412: .  -snes_ksp_ew_rtol0 <rtol0> - Sets rtol0
4413: .  -snes_ksp_ew_rtolmax <rtolmax> - Sets rtolmax
4414: .  -snes_ksp_ew_gamma <gamma> - Sets gamma
4415: .  -snes_ksp_ew_alpha <alpha> - Sets alpha
4416: .  -snes_ksp_ew_alpha2 <alpha2> - Sets alpha2
4417: -  -snes_ksp_ew_threshold <threshold> - Sets threshold

4419:    Notes:
4420:    Currently, the default is to use a constant relative tolerance for
4421:    the inner linear solvers.  Alternatively, one can use the
4422:    Eisenstat-Walker method, where the relative convergence tolerance
4423:    is reset at each Newton iteration according progress of the nonlinear
4424:    solver.

4426:    Level: advanced

4428:    Reference:
4429:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4430:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4432: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4434: .seealso: SNESKSPGetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4435: @*/
4436: PetscErrorCode  SNESKSPSetUseEW(SNES snes,PetscBool flag)
4437: {
4441:   snes->ksp_ewconv = flag;
4442:   return(0);
4443: }

4447: /*@
4448:    SNESKSPGetUseEW - Gets if SNES is using Eisenstat-Walker method
4449:    for computing relative tolerance for linear solvers within an
4450:    inexact Newton method.

4452:    Not Collective

4454:    Input Parameter:
4455: .  snes - SNES context

4457:    Output Parameter:
4458: .  flag - PETSC_TRUE or PETSC_FALSE

4460:    Notes:
4461:    Currently, the default is to use a constant relative tolerance for
4462:    the inner linear solvers.  Alternatively, one can use the
4463:    Eisenstat-Walker method, where the relative convergence tolerance
4464:    is reset at each Newton iteration according progress of the nonlinear
4465:    solver.

4467:    Level: advanced

4469:    Reference:
4470:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4471:    inexact Newton method", SISC 17 (1), pp.16-32, 1996.

4473: .keywords: SNES, KSP, Eisenstat, Walker, convergence, test, inexact, Newton

4475: .seealso: SNESKSPSetUseEW(), SNESKSPGetParametersEW(), SNESKSPSetParametersEW()
4476: @*/
4477: PetscErrorCode  SNESKSPGetUseEW(SNES snes, PetscBool  *flag)
4478: {
4482:   *flag = snes->ksp_ewconv;
4483:   return(0);
4484: }

4488: /*@
4489:    SNESKSPSetParametersEW - Sets parameters for Eisenstat-Walker
4490:    convergence criteria for the linear solvers within an inexact
4491:    Newton method.

4493:    Logically Collective on SNES

4495:    Input Parameters:
4496: +    snes - SNES context
4497: .    version - version 1, 2 (default is 2) or 3
4498: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4499: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4500: .    gamma - multiplicative factor for version 2 rtol computation
4501:              (0 <= gamma2 <= 1)
4502: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4503: .    alpha2 - power for safeguard
4504: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4506:    Note:
4507:    Version 3 was contributed by Luis Chacon, June 2006.

4509:    Use PETSC_DEFAULT to retain the default for any of the parameters.

4511:    Level: advanced

4513:    Reference:
4514:    S. C. Eisenstat and H. F. Walker, "Choosing the forcing terms in an
4515:    inexact Newton method", Utah State University Math. Stat. Dept. Res.
4516:    Report 6/94/75, June, 1994, to appear in SIAM J. Sci. Comput.

4518: .keywords: SNES, KSP, Eisenstat, Walker, set, parameters

4520: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPGetParametersEW()
4521: @*/
4522: PetscErrorCode  SNESKSPSetParametersEW(SNES snes,PetscInt version,PetscReal rtol_0,PetscReal rtol_max,PetscReal gamma,PetscReal alpha,PetscReal alpha2,PetscReal threshold)
4523: {
4524:   SNESKSPEW *kctx;

4528:   kctx = (SNESKSPEW*)snes->kspconvctx;
4529:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");

4538:   if (version != PETSC_DEFAULT)   kctx->version   = version;
4539:   if (rtol_0 != PETSC_DEFAULT)    kctx->rtol_0    = rtol_0;
4540:   if (rtol_max != PETSC_DEFAULT)  kctx->rtol_max  = rtol_max;
4541:   if (gamma != PETSC_DEFAULT)     kctx->gamma     = gamma;
4542:   if (alpha != PETSC_DEFAULT)     kctx->alpha     = alpha;
4543:   if (alpha2 != PETSC_DEFAULT)    kctx->alpha2    = alpha2;
4544:   if (threshold != PETSC_DEFAULT) kctx->threshold = threshold;

4546:   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);
4547:   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);
4548:   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);
4549:   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);
4550:   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);
4551:   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);
4552:   return(0);
4553: }

4557: /*@
4558:    SNESKSPGetParametersEW - Gets parameters for Eisenstat-Walker
4559:    convergence criteria for the linear solvers within an inexact
4560:    Newton method.

4562:    Not Collective

4564:    Input Parameters:
4565:      snes - SNES context

4567:    Output Parameters:
4568: +    version - version 1, 2 (default is 2) or 3
4569: .    rtol_0 - initial relative tolerance (0 <= rtol_0 < 1)
4570: .    rtol_max - maximum relative tolerance (0 <= rtol_max < 1)
4571: .    gamma - multiplicative factor for version 2 rtol computation (0 <= gamma2 <= 1)
4572: .    alpha - power for version 2 rtol computation (1 < alpha <= 2)
4573: .    alpha2 - power for safeguard
4574: -    threshold - threshold for imposing safeguard (0 < threshold < 1)

4576:    Level: advanced

4578: .keywords: SNES, KSP, Eisenstat, Walker, get, parameters

4580: .seealso: SNESKSPSetUseEW(), SNESKSPGetUseEW(), SNESKSPSetParametersEW()
4581: @*/
4582: PetscErrorCode  SNESKSPGetParametersEW(SNES snes,PetscInt *version,PetscReal *rtol_0,PetscReal *rtol_max,PetscReal *gamma,PetscReal *alpha,PetscReal *alpha2,PetscReal *threshold)
4583: {
4584:   SNESKSPEW *kctx;

4588:   kctx = (SNESKSPEW*)snes->kspconvctx;
4589:   if (!kctx) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"No Eisenstat-Walker context existing");
4590:   if (version)   *version   = kctx->version;
4591:   if (rtol_0)    *rtol_0    = kctx->rtol_0;
4592:   if (rtol_max)  *rtol_max  = kctx->rtol_max;
4593:   if (gamma)     *gamma     = kctx->gamma;
4594:   if (alpha)     *alpha     = kctx->alpha;
4595:   if (alpha2)    *alpha2    = kctx->alpha2;
4596:   if (threshold) *threshold = kctx->threshold;
4597:   return(0);
4598: }

4602:  PetscErrorCode KSPPreSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
4603: {
4605:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
4606:   PetscReal      rtol  = PETSC_DEFAULT,stol;

4609:   if (!snes->ksp_ewconv) return(0);
4610:   if (!snes->iter) {
4611:     rtol = kctx->rtol_0; /* first time in, so use the original user rtol */
4612:     VecNorm(snes->vec_func,NORM_2,&kctx->norm_first);
4613:   }
4614:   else {
4615:     if (kctx->version == 1) {
4616:       rtol = (snes->norm - kctx->lresid_last)/kctx->norm_last;
4617:       if (rtol < 0.0) rtol = -rtol;
4618:       stol = PetscPowReal(kctx->rtol_last,kctx->alpha2);
4619:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
4620:     } else if (kctx->version == 2) {
4621:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
4622:       stol = kctx->gamma * PetscPowReal(kctx->rtol_last,kctx->alpha);
4623:       if (stol > kctx->threshold) rtol = PetscMax(rtol,stol);
4624:     } else if (kctx->version == 3) { /* contributed by Luis Chacon, June 2006. */
4625:       rtol = kctx->gamma * PetscPowReal(snes->norm/kctx->norm_last,kctx->alpha);
4626:       /* safeguard: avoid sharp decrease of rtol */
4627:       stol = kctx->gamma*PetscPowReal(kctx->rtol_last,kctx->alpha);
4628:       stol = PetscMax(rtol,stol);
4629:       rtol = PetscMin(kctx->rtol_0,stol);
4630:       /* safeguard: avoid oversolving */
4631:       stol = kctx->gamma*(kctx->norm_first*snes->rtol)/snes->norm;
4632:       stol = PetscMax(rtol,stol);
4633:       rtol = PetscMin(kctx->rtol_0,stol);
4634:     } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only versions 1, 2 or 3 are supported: %D",kctx->version);
4635:   }
4636:   /* safeguard: avoid rtol greater than one */
4637:   rtol = PetscMin(rtol,kctx->rtol_max);
4638:   KSPSetTolerances(ksp,rtol,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT);
4639:   PetscInfo3(snes,"iter %D, Eisenstat-Walker (version %D) KSP rtol=%g\n",snes->iter,kctx->version,(double)rtol);
4640:   return(0);
4641: }

4645: PetscErrorCode KSPPostSolve_SNESEW(KSP ksp, Vec b, Vec x, SNES snes)
4646: {
4648:   SNESKSPEW      *kctx = (SNESKSPEW*)snes->kspconvctx;
4649:   PCSide         pcside;
4650:   Vec            lres;

4653:   if (!snes->ksp_ewconv) return(0);
4654:   KSPGetTolerances(ksp,&kctx->rtol_last,0,0,0);
4655:   kctx->norm_last = snes->norm;
4656:   if (kctx->version == 1) {
4657:     PC        pc;
4658:     PetscBool isNone;

4660:     KSPGetPC(ksp, &pc);
4661:     PetscObjectTypeCompare((PetscObject) pc, PCNONE, &isNone);
4662:     KSPGetPCSide(ksp,&pcside);
4663:      if (pcside == PC_RIGHT || isNone) { /* XXX Should we also test KSP_UNPRECONDITIONED_NORM ? */
4664:       /* KSP residual is true linear residual */
4665:       KSPGetResidualNorm(ksp,&kctx->lresid_last);
4666:     } else {
4667:       /* KSP residual is preconditioned residual */
4668:       /* compute true linear residual norm */
4669:       VecDuplicate(b,&lres);
4670:       MatMult(snes->jacobian,x,lres);
4671:       VecAYPX(lres,-1.0,b);
4672:       VecNorm(lres,NORM_2,&kctx->lresid_last);
4673:       VecDestroy(&lres);
4674:     }
4675:   }
4676:   return(0);
4677: }

4681: /*@
4682:    SNESGetKSP - Returns the KSP context for a SNES solver.

4684:    Not Collective, but if SNES object is parallel, then KSP object is parallel

4686:    Input Parameter:
4687: .  snes - the SNES context

4689:    Output Parameter:
4690: .  ksp - the KSP context

4692:    Notes:
4693:    The user can then directly manipulate the KSP context to set various
4694:    options, etc.  Likewise, the user can then extract and manipulate the
4695:    PC contexts as well.

4697:    Level: beginner

4699: .keywords: SNES, nonlinear, get, KSP, context

4701: .seealso: KSPGetPC(), SNESCreate(), KSPCreate(), SNESSetKSP()
4702: @*/
4703: PetscErrorCode  SNESGetKSP(SNES snes,KSP *ksp)
4704: {


4711:   if (!snes->ksp) {
4712:     PetscBool monitor = PETSC_FALSE;

4714:     KSPCreate(PetscObjectComm((PetscObject)snes),&snes->ksp);
4715:     PetscObjectIncrementTabLevel((PetscObject)snes->ksp,(PetscObject)snes,1);
4716:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->ksp);

4718:     KSPSetPreSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPreSolve_SNESEW,snes);
4719:     KSPSetPostSolve(snes->ksp,(PetscErrorCode (*)(KSP,Vec,Vec,void*))KSPPostSolve_SNESEW,snes);

4721:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-ksp_monitor_snes",&monitor,NULL);
4722:     if (monitor) {
4723:       KSPMonitorSet(snes->ksp,KSPMonitorSNES,snes,NULL);
4724:     }
4725:     monitor = PETSC_FALSE;
4726:     PetscOptionsGetBool(((PetscObject)snes)->prefix,"-ksp_monitor_snes_lg",&monitor,NULL);
4727:     if (monitor) {
4728:       PetscObject *objs;
4729:       KSPMonitorSNESLGResidualNormCreate(0,0,PETSC_DECIDE,PETSC_DECIDE,600,600,&objs);
4730:       objs[0] = (PetscObject) snes;
4731:       KSPMonitorSet(snes->ksp,(PetscErrorCode (*)(KSP,PetscInt,PetscReal,void*))KSPMonitorSNESLGResidualNorm,objs,(PetscErrorCode (*)(void**))KSPMonitorSNESLGResidualNormDestroy);
4732:     }
4733:   }
4734:   *ksp = snes->ksp;
4735:   return(0);
4736: }


4739: #include <petsc/private/dmimpl.h>
4742: /*@
4743:    SNESSetDM - Sets the DM that may be used by some preconditioners

4745:    Logically Collective on SNES

4747:    Input Parameters:
4748: +  snes - the preconditioner context
4749: -  dm - the dm

4751:    Level: intermediate

4753: .seealso: SNESGetDM(), KSPSetDM(), KSPGetDM()
4754: @*/
4755: PetscErrorCode  SNESSetDM(SNES snes,DM dm)
4756: {
4758:   KSP            ksp;
4759:   DMSNES         sdm;

4763:   if (dm) {PetscObjectReference((PetscObject)dm);}
4764:   if (snes->dm) {               /* Move the DMSNES context over to the new DM unless the new DM already has one */
4765:     if (snes->dm->dmsnes && snes->dmAuto && !dm->dmsnes) {
4766:       DMCopyDMSNES(snes->dm,dm);
4767:       DMGetDMSNES(snes->dm,&sdm);
4768:       if (sdm->originaldm == snes->dm) sdm->originaldm = dm; /* Grant write privileges to the replacement DM */
4769:     }
4770:     DMDestroy(&snes->dm);
4771:   }
4772:   snes->dm     = dm;
4773:   snes->dmAuto = PETSC_FALSE;

4775:   SNESGetKSP(snes,&ksp);
4776:   KSPSetDM(ksp,dm);
4777:   KSPSetDMActive(ksp,PETSC_FALSE);
4778:   if (snes->pc) {
4779:     SNESSetDM(snes->pc, snes->dm);
4780:     SNESSetNPCSide(snes,snes->pcside);
4781:   }
4782:   return(0);
4783: }

4787: /*@
4788:    SNESGetDM - Gets the DM that may be used by some preconditioners

4790:    Not Collective but DM obtained is parallel on SNES

4792:    Input Parameter:
4793: . snes - the preconditioner context

4795:    Output Parameter:
4796: .  dm - the dm

4798:    Level: intermediate

4800: .seealso: SNESSetDM(), KSPSetDM(), KSPGetDM()
4801: @*/
4802: PetscErrorCode  SNESGetDM(SNES snes,DM *dm)
4803: {

4808:   if (!snes->dm) {
4809:     DMShellCreate(PetscObjectComm((PetscObject)snes),&snes->dm);
4810:     snes->dmAuto = PETSC_TRUE;
4811:   }
4812:   *dm = snes->dm;
4813:   return(0);
4814: }

4818: /*@
4819:   SNESSetNPC - Sets the nonlinear preconditioner to be used.

4821:   Collective on SNES

4823:   Input Parameters:
4824: + snes - iterative context obtained from SNESCreate()
4825: - pc   - the preconditioner object

4827:   Notes:
4828:   Use SNESGetNPC() to retrieve the preconditioner context (for example,
4829:   to configure it using the API).

4831:   Level: developer

4833: .keywords: SNES, set, precondition
4834: .seealso: SNESGetNPC(), SNESHasNPC()
4835: @*/
4836: PetscErrorCode SNESSetNPC(SNES snes, SNES pc)
4837: {

4844:   PetscObjectReference((PetscObject) pc);
4845:   SNESDestroy(&snes->pc);
4846:   snes->pc = pc;
4847:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->pc);
4848:   return(0);
4849: }

4853: /*@
4854:   SNESGetNPC - Creates a nonlinear preconditioning solver (SNES) to be used to precondition the nonlinear solver.

4856:   Not Collective

4858:   Input Parameter:
4859: . snes - iterative context obtained from SNESCreate()

4861:   Output Parameter:
4862: . pc - preconditioner context

4864:   Notes: If a SNES was previously set with SNESSetNPC() then that SNES is returned.

4866:   Level: developer

4868: .keywords: SNES, get, preconditioner
4869: .seealso: SNESSetNPC(), SNESHasNPC()
4870: @*/
4871: PetscErrorCode SNESGetNPC(SNES snes, SNES *pc)
4872: {
4874:   const char     *optionsprefix;

4879:   if (!snes->pc) {
4880:     SNESCreate(PetscObjectComm((PetscObject)snes),&snes->pc);
4881:     PetscObjectIncrementTabLevel((PetscObject)snes->pc,(PetscObject)snes,1);
4882:     PetscLogObjectParent((PetscObject)snes,(PetscObject)snes->pc);
4883:     SNESGetOptionsPrefix(snes,&optionsprefix);
4884:     SNESSetOptionsPrefix(snes->pc,optionsprefix);
4885:     SNESAppendOptionsPrefix(snes->pc,"npc_");
4886:     SNESSetCountersReset(snes->pc,PETSC_FALSE);
4887:   }
4888:   *pc = snes->pc;
4889:   return(0);
4890: }

4894: /*@
4895:   SNESHasNPC - Returns whether a nonlinear preconditioner exists

4897:   Not Collective

4899:   Input Parameter:
4900: . snes - iterative context obtained from SNESCreate()

4902:   Output Parameter:
4903: . has_npc - whether the SNES has an NPC or not

4905:   Level: developer

4907: .keywords: SNES, has, preconditioner
4908: .seealso: SNESSetNPC(), SNESGetNPC()
4909: @*/
4910: PetscErrorCode SNESHasNPC(SNES snes, PetscBool *has_npc)
4911: {
4914:   *has_npc = (PetscBool) (snes->pc != NULL);
4915:   return(0);
4916: }

4920: /*@
4921:     SNESSetNPCSide - Sets the preconditioning side.

4923:     Logically Collective on SNES

4925:     Input Parameter:
4926: .   snes - iterative context obtained from SNESCreate()

4928:     Output Parameter:
4929: .   side - the preconditioning side, where side is one of
4930: .vb
4931:       PC_LEFT - left preconditioning (default)
4932:       PC_RIGHT - right preconditioning
4933: .ve

4935:     Options Database Keys:
4936: .   -snes_pc_side <right,left>

4938:     Level: intermediate

4940: .keywords: SNES, set, right, left, side, preconditioner, flag

4942: .seealso: SNESGetNPCSide(), KSPSetPCSide()
4943: @*/
4944: PetscErrorCode  SNESSetNPCSide(SNES snes,PCSide side)
4945: {
4949:   snes->pcside = side;
4950:   return(0);
4951: }

4955: /*@
4956:     SNESGetNPCSide - Gets the preconditioning side.

4958:     Not Collective

4960:     Input Parameter:
4961: .   snes - iterative context obtained from SNESCreate()

4963:     Output Parameter:
4964: .   side - the preconditioning side, where side is one of
4965: .vb
4966:       PC_LEFT - left preconditioning (default)
4967:       PC_RIGHT - right preconditioning
4968: .ve

4970:     Level: intermediate

4972: .keywords: SNES, get, right, left, side, preconditioner, flag

4974: .seealso: SNESSetNPCSide(), KSPGetPCSide()
4975: @*/
4976: PetscErrorCode  SNESGetNPCSide(SNES snes,PCSide *side)
4977: {
4981:   *side = snes->pcside;
4982:   return(0);
4983: }

4987: /*@
4988:   SNESSetLineSearch - Sets the linesearch on the SNES instance.

4990:   Collective on SNES

4992:   Input Parameters:
4993: + snes - iterative context obtained from SNESCreate()
4994: - linesearch   - the linesearch object

4996:   Notes:
4997:   Use SNESGetLineSearch() to retrieve the preconditioner context (for example,
4998:   to configure it using the API).

5000:   Level: developer

5002: .keywords: SNES, set, linesearch
5003: .seealso: SNESGetLineSearch()
5004: @*/
5005: PetscErrorCode SNESSetLineSearch(SNES snes, SNESLineSearch linesearch)
5006: {

5013:   PetscObjectReference((PetscObject) linesearch);
5014:   SNESLineSearchDestroy(&snes->linesearch);

5016:   snes->linesearch = linesearch;

5018:   PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5019:   return(0);
5020: }

5024: /*@
5025:   SNESGetLineSearch - Returns a pointer to the line search context set with SNESSetLineSearch()
5026:   or creates a default line search instance associated with the SNES and returns it.

5028:   Not Collective

5030:   Input Parameter:
5031: . snes - iterative context obtained from SNESCreate()

5033:   Output Parameter:
5034: . linesearch - linesearch context

5036:   Level: beginner

5038: .keywords: SNES, get, linesearch
5039: .seealso: SNESSetLineSearch(), SNESLineSearchCreate()
5040: @*/
5041: PetscErrorCode SNESGetLineSearch(SNES snes, SNESLineSearch *linesearch)
5042: {
5044:   const char     *optionsprefix;

5049:   if (!snes->linesearch) {
5050:     SNESGetOptionsPrefix(snes, &optionsprefix);
5051:     SNESLineSearchCreate(PetscObjectComm((PetscObject)snes), &snes->linesearch);
5052:     SNESLineSearchSetSNES(snes->linesearch, snes);
5053:     SNESLineSearchAppendOptionsPrefix(snes->linesearch, optionsprefix);
5054:     PetscObjectIncrementTabLevel((PetscObject) snes->linesearch, (PetscObject) snes, 1);
5055:     PetscLogObjectParent((PetscObject)snes, (PetscObject)snes->linesearch);
5056:   }
5057:   *linesearch = snes->linesearch;
5058:   return(0);
5059: }

5061: #if defined(PETSC_HAVE_MATLAB_ENGINE)
5062: #include <mex.h>

5064: typedef struct {char *funcname; mxArray *ctx;} SNESMatlabContext;

5068: /*
5069:    SNESComputeFunction_Matlab - Calls the function that has been set with SNESSetFunctionMatlab().

5071:    Collective on SNES

5073:    Input Parameters:
5074: +  snes - the SNES context
5075: -  x - input vector

5077:    Output Parameter:
5078: .  y - function vector, as set by SNESSetFunction()

5080:    Notes:
5081:    SNESComputeFunction() is typically used within nonlinear solvers
5082:    implementations, so most users would not generally call this routine
5083:    themselves.

5085:    Level: developer

5087: .keywords: SNES, nonlinear, compute, function

5089: .seealso: SNESSetFunction(), SNESGetFunction()
5090: */
5091: PetscErrorCode  SNESComputeFunction_Matlab(SNES snes,Vec x,Vec y, void *ctx)
5092: {
5093:   PetscErrorCode    ierr;
5094:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5095:   int               nlhs  = 1,nrhs = 5;
5096:   mxArray           *plhs[1],*prhs[5];
5097:   long long int     lx = 0,ly = 0,ls = 0;


5106:   /* call Matlab function in ctx with arguments x and y */

5108:   PetscMemcpy(&ls,&snes,sizeof(snes));
5109:   PetscMemcpy(&lx,&x,sizeof(x));
5110:   PetscMemcpy(&ly,&y,sizeof(x));
5111:   prhs[0] = mxCreateDoubleScalar((double)ls);
5112:   prhs[1] = mxCreateDoubleScalar((double)lx);
5113:   prhs[2] = mxCreateDoubleScalar((double)ly);
5114:   prhs[3] = mxCreateString(sctx->funcname);
5115:   prhs[4] = sctx->ctx;
5116:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeFunctionInternal");
5117:   mxGetScalar(plhs[0]);
5118:   mxDestroyArray(prhs[0]);
5119:   mxDestroyArray(prhs[1]);
5120:   mxDestroyArray(prhs[2]);
5121:   mxDestroyArray(prhs[3]);
5122:   mxDestroyArray(plhs[0]);
5123:   return(0);
5124: }

5128: /*
5129:    SNESSetFunctionMatlab - Sets the function evaluation routine and function
5130:    vector for use by the SNES routines in solving systems of nonlinear
5131:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

5133:    Logically Collective on SNES

5135:    Input Parameters:
5136: +  snes - the SNES context
5137: .  r - vector to store function value
5138: -  f - function evaluation routine

5140:    Notes:
5141:    The Newton-like methods typically solve linear systems of the form
5142: $      f'(x) x = -f(x),
5143:    where f'(x) denotes the Jacobian matrix and f(x) is the function.

5145:    Level: beginner

5147:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5149: .keywords: SNES, nonlinear, set, function

5151: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5152: */
5153: PetscErrorCode  SNESSetFunctionMatlab(SNES snes,Vec r,const char *f,mxArray *ctx)
5154: {
5155:   PetscErrorCode    ierr;
5156:   SNESMatlabContext *sctx;

5159:   /* currently sctx is memory bleed */
5160:   PetscNew(&sctx);
5161:   PetscStrallocpy(f,&sctx->funcname);
5162:   /*
5163:      This should work, but it doesn't
5164:   sctx->ctx = ctx;
5165:   mexMakeArrayPersistent(sctx->ctx);
5166:   */
5167:   sctx->ctx = mxDuplicateArray(ctx);
5168:   SNESSetFunction(snes,r,SNESComputeFunction_Matlab,sctx);
5169:   return(0);
5170: }

5174: /*
5175:    SNESComputeJacobian_Matlab - Calls the function that has been set with SNESSetJacobianMatlab().

5177:    Collective on SNES

5179:    Input Parameters:
5180: +  snes - the SNES context
5181: .  x - input vector
5182: .  A, B - the matrices
5183: -  ctx - user context

5185:    Level: developer

5187: .keywords: SNES, nonlinear, compute, function

5189: .seealso: SNESSetFunction(), SNESGetFunction()
5190: @*/
5191: PetscErrorCode  SNESComputeJacobian_Matlab(SNES snes,Vec x,Mat A,Mat B,void *ctx)
5192: {
5193:   PetscErrorCode    ierr;
5194:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5195:   int               nlhs  = 2,nrhs = 6;
5196:   mxArray           *plhs[2],*prhs[6];
5197:   long long int     lx = 0,lA = 0,ls = 0, lB = 0;


5203:   /* call Matlab function in ctx with arguments x and y */

5205:   PetscMemcpy(&ls,&snes,sizeof(snes));
5206:   PetscMemcpy(&lx,&x,sizeof(x));
5207:   PetscMemcpy(&lA,A,sizeof(x));
5208:   PetscMemcpy(&lB,B,sizeof(x));
5209:   prhs[0] = mxCreateDoubleScalar((double)ls);
5210:   prhs[1] = mxCreateDoubleScalar((double)lx);
5211:   prhs[2] = mxCreateDoubleScalar((double)lA);
5212:   prhs[3] = mxCreateDoubleScalar((double)lB);
5213:   prhs[4] = mxCreateString(sctx->funcname);
5214:   prhs[5] = sctx->ctx;
5215:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESComputeJacobianInternal");
5216:   mxGetScalar(plhs[0]);
5217:   mxDestroyArray(prhs[0]);
5218:   mxDestroyArray(prhs[1]);
5219:   mxDestroyArray(prhs[2]);
5220:   mxDestroyArray(prhs[3]);
5221:   mxDestroyArray(prhs[4]);
5222:   mxDestroyArray(plhs[0]);
5223:   mxDestroyArray(plhs[1]);
5224:   return(0);
5225: }

5229: /*
5230:    SNESSetJacobianMatlab - Sets the Jacobian function evaluation routine and two empty Jacobian matrices
5231:    vector for use by the SNES routines in solving systems of nonlinear
5232:    equations from MATLAB. Here the function is a string containing the name of a MATLAB function

5234:    Logically Collective on SNES

5236:    Input Parameters:
5237: +  snes - the SNES context
5238: .  A,B - Jacobian matrices
5239: .  J - function evaluation routine
5240: -  ctx - user context

5242:    Level: developer

5244:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5246: .keywords: SNES, nonlinear, set, function

5248: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction(), J
5249: */
5250: PetscErrorCode  SNESSetJacobianMatlab(SNES snes,Mat A,Mat B,const char *J,mxArray *ctx)
5251: {
5252:   PetscErrorCode    ierr;
5253:   SNESMatlabContext *sctx;

5256:   /* currently sctx is memory bleed */
5257:   PetscNew(&sctx);
5258:   PetscStrallocpy(J,&sctx->funcname);
5259:   /*
5260:      This should work, but it doesn't
5261:   sctx->ctx = ctx;
5262:   mexMakeArrayPersistent(sctx->ctx);
5263:   */
5264:   sctx->ctx = mxDuplicateArray(ctx);
5265:   SNESSetJacobian(snes,A,B,SNESComputeJacobian_Matlab,sctx);
5266:   return(0);
5267: }

5271: /*
5272:    SNESMonitor_Matlab - Calls the function that has been set with SNESMonitorSetMatlab().

5274:    Collective on SNES

5276: .seealso: SNESSetFunction(), SNESGetFunction()
5277: @*/
5278: PetscErrorCode  SNESMonitor_Matlab(SNES snes,PetscInt it, PetscReal fnorm, void *ctx)
5279: {
5280:   PetscErrorCode    ierr;
5281:   SNESMatlabContext *sctx = (SNESMatlabContext*)ctx;
5282:   int               nlhs  = 1,nrhs = 6;
5283:   mxArray           *plhs[1],*prhs[6];
5284:   long long int     lx = 0,ls = 0;
5285:   Vec               x  = snes->vec_sol;


5290:   PetscMemcpy(&ls,&snes,sizeof(snes));
5291:   PetscMemcpy(&lx,&x,sizeof(x));
5292:   prhs[0] = mxCreateDoubleScalar((double)ls);
5293:   prhs[1] = mxCreateDoubleScalar((double)it);
5294:   prhs[2] = mxCreateDoubleScalar((double)fnorm);
5295:   prhs[3] = mxCreateDoubleScalar((double)lx);
5296:   prhs[4] = mxCreateString(sctx->funcname);
5297:   prhs[5] = sctx->ctx;
5298:   mexCallMATLAB(nlhs,plhs,nrhs,prhs,"PetscSNESMonitorInternal");
5299:   mxGetScalar(plhs[0]);
5300:   mxDestroyArray(prhs[0]);
5301:   mxDestroyArray(prhs[1]);
5302:   mxDestroyArray(prhs[2]);
5303:   mxDestroyArray(prhs[3]);
5304:   mxDestroyArray(prhs[4]);
5305:   mxDestroyArray(plhs[0]);
5306:   return(0);
5307: }

5311: /*
5312:    SNESMonitorSetMatlab - Sets the monitor function from MATLAB

5314:    Level: developer

5316:    Developer Note:  This bleeds the allocated memory SNESMatlabContext *sctx;

5318: .keywords: SNES, nonlinear, set, function

5320: .seealso: SNESGetFunction(), SNESComputeFunction(), SNESSetJacobian(), SNESSetFunction()
5321: */
5322: PetscErrorCode  SNESMonitorSetMatlab(SNES snes,const char *f,mxArray *ctx)
5323: {
5324:   PetscErrorCode    ierr;
5325:   SNESMatlabContext *sctx;

5328:   /* currently sctx is memory bleed */
5329:   PetscNew(&sctx);
5330:   PetscStrallocpy(f,&sctx->funcname);
5331:   /*
5332:      This should work, but it doesn't
5333:   sctx->ctx = ctx;
5334:   mexMakeArrayPersistent(sctx->ctx);
5335:   */
5336:   sctx->ctx = mxDuplicateArray(ctx);
5337:   SNESMonitorSet(snes,SNESMonitor_Matlab,sctx,NULL);
5338:   return(0);
5339: }

5341: #endif