Actual source code: snesngmres.c
petsc-3.7.5 2017-01-01
1: #include <../src/snes/impls/ngmres/snesngmres.h> /*I "petscsnes.h" I*/
2: #include <petscblaslapack.h>
3: #include <petscdm.h>
5: const char *const SNESNGMRESRestartTypes[] = {"NONE","PERIODIC","DIFFERENCE","SNESNGMRESRestartType","SNES_NGMRES_RESTART_",0};
6: const char *const SNESNGMRESSelectTypes[] = {"NONE","DIFFERENCE","LINESEARCH","SNESNGMRESSelectType","SNES_NGMRES_SELECT_",0};
10: PetscErrorCode SNESReset_NGMRES(SNES snes)
11: {
12: SNES_NGMRES *ngmres = (SNES_NGMRES*) snes->data;
16: VecDestroyVecs(ngmres->msize,&ngmres->Fdot);
17: VecDestroyVecs(ngmres->msize,&ngmres->Xdot);
18: SNESLineSearchDestroy(&ngmres->additive_linesearch);
19: return(0);
20: }
24: PetscErrorCode SNESDestroy_NGMRES(SNES snes)
25: {
27: SNES_NGMRES *ngmres = (SNES_NGMRES*)snes->data;
30: SNESReset_NGMRES(snes);
31: PetscFree5(ngmres->h,ngmres->beta,ngmres->xi,ngmres->fnorms,ngmres->q);
32: PetscFree(ngmres->s);
33: PetscFree(ngmres->xnorms);
34: #if PETSC_USE_COMPLEX
35: PetscFree(ngmres->rwork);
36: #endif
37: PetscFree(ngmres->work);
38: PetscFree(snes->data);
39: return(0);
40: }
44: PetscErrorCode SNESSetUp_NGMRES(SNES snes)
45: {
46: SNES_NGMRES *ngmres = (SNES_NGMRES*) snes->data;
47: const char *optionsprefix;
48: PetscInt msize,hsize;
50: DM dm;
53: if (snes->pc && snes->pcside == PC_LEFT && snes->functype == SNES_FUNCTION_UNPRECONDITIONED) {
54: SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE,"SNESNGMRES does not support left preconditioning with unpreconditioned function");
55: }
56: if (snes->pcside == PC_LEFT && snes->functype == SNES_FUNCTION_DEFAULT) snes->functype = SNES_FUNCTION_PRECONDITIONED;
57: SNESSetWorkVecs(snes,5);
59: if (!snes->vec_sol) {
60: SNESGetDM(snes,&dm);
61: DMCreateGlobalVector(dm,&snes->vec_sol);
62: }
64: if (!ngmres->Xdot) {VecDuplicateVecs(snes->vec_sol,ngmres->msize,&ngmres->Xdot);}
65: if (!ngmres->Fdot) {VecDuplicateVecs(snes->vec_sol,ngmres->msize,&ngmres->Fdot);}
66: if (!ngmres->setup_called) {
67: msize = ngmres->msize; /* restart size */
68: hsize = msize * msize;
70: /* explicit least squares minimization solve */
71: PetscMalloc5(hsize,&ngmres->h, msize,&ngmres->beta, msize,&ngmres->xi, msize,&ngmres->fnorms, hsize,&ngmres->q);
72: PetscMalloc1(msize,&ngmres->xnorms);
73: ngmres->nrhs = 1;
74: ngmres->lda = msize;
75: ngmres->ldb = msize;
76: PetscMalloc1(msize,&ngmres->s);
77: PetscMemzero(ngmres->h, hsize*sizeof(PetscScalar));
78: PetscMemzero(ngmres->q, hsize*sizeof(PetscScalar));
79: PetscMemzero(ngmres->xi, msize*sizeof(PetscScalar));
80: PetscMemzero(ngmres->beta,msize*sizeof(PetscScalar));
81: ngmres->lwork = 12*msize;
82: #if PETSC_USE_COMPLEX
83: PetscMalloc1(ngmres->lwork,&ngmres->rwork);
84: #endif
85: PetscMalloc1(ngmres->lwork,&ngmres->work);
86: }
88: /* linesearch setup */
89: SNESGetOptionsPrefix(snes,&optionsprefix);
91: if (ngmres->select_type == SNES_NGMRES_SELECT_LINESEARCH) {
92: SNESLineSearchCreate(PetscObjectComm((PetscObject)snes),&ngmres->additive_linesearch);
93: SNESLineSearchSetSNES(ngmres->additive_linesearch,snes);
94: SNESLineSearchSetType(ngmres->additive_linesearch,SNESLINESEARCHL2);
95: SNESLineSearchAppendOptionsPrefix(ngmres->additive_linesearch,"additive_");
96: SNESLineSearchAppendOptionsPrefix(ngmres->additive_linesearch,optionsprefix);
97: SNESLineSearchSetFromOptions(ngmres->additive_linesearch);
98: }
100: ngmres->setup_called = PETSC_TRUE;
101: return(0);
102: }
106: PetscErrorCode SNESSetFromOptions_NGMRES(PetscOptionItems *PetscOptionsObject,SNES snes)
107: {
108: SNES_NGMRES *ngmres = (SNES_NGMRES*) snes->data;
110: PetscBool debug = PETSC_FALSE;
111: SNESLineSearch linesearch;
114: PetscOptionsHead(PetscOptionsObject,"SNES NGMRES options");
115: PetscOptionsEnum("-snes_ngmres_select_type","Select type","SNESNGMRESSetSelectType",SNESNGMRESSelectTypes,
116: (PetscEnum)ngmres->select_type,(PetscEnum*)&ngmres->select_type,NULL);
117: PetscOptionsEnum("-snes_ngmres_restart_type","Restart type","SNESNGMRESSetRestartType",SNESNGMRESRestartTypes,
118: (PetscEnum)ngmres->restart_type,(PetscEnum*)&ngmres->restart_type,NULL);
119: PetscOptionsBool("-snes_ngmres_candidate", "Use candidate storage", "SNES",ngmres->candidate,&ngmres->candidate,NULL);
120: PetscOptionsBool("-snes_ngmres_approxfunc","Linearly approximate the function", "SNES",ngmres->approxfunc,&ngmres->approxfunc,NULL);
121: PetscOptionsInt("-snes_ngmres_m", "Number of directions", "SNES",ngmres->msize,&ngmres->msize,NULL);
122: PetscOptionsInt("-snes_ngmres_restart", "Iterations before forced restart", "SNES",ngmres->restart_periodic,&ngmres->restart_periodic,NULL);
123: PetscOptionsInt("-snes_ngmres_restart_it", "Tolerance iterations before restart","SNES",ngmres->restart_it,&ngmres->restart_it,NULL);
124: PetscOptionsBool("-snes_ngmres_monitor", "Monitor actions of NGMRES", "SNES",ngmres->monitor ? PETSC_TRUE : PETSC_FALSE,&debug,NULL);
125: if (debug) {
126: ngmres->monitor = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));
127: }
128: PetscOptionsReal("-snes_ngmres_gammaA", "Residual selection constant", "SNES",ngmres->gammaA,&ngmres->gammaA,NULL);
129: PetscOptionsReal("-snes_ngmres_gammaC", "Residual restart constant", "SNES",ngmres->gammaC,&ngmres->gammaC,NULL);
130: PetscOptionsReal("-snes_ngmres_epsilonB", "Difference selection constant", "SNES",ngmres->epsilonB,&ngmres->epsilonB,NULL);
131: PetscOptionsReal("-snes_ngmres_deltaB", "Difference residual selection constant", "SNES",ngmres->deltaB,&ngmres->deltaB,NULL);
132: PetscOptionsBool("-snes_ngmres_single_reduction", "Aggregate reductions", "SNES",ngmres->singlereduction,&ngmres->singlereduction,NULL);
133: PetscOptionsBool("-snes_ngmres_restart_fm_rise", "Restart on F_M residual rise", "SNESNGMRESSetRestartFmRise",ngmres->restart_fm_rise,&ngmres->restart_fm_rise,NULL);
134: PetscOptionsTail();
135: if ((ngmres->gammaA > ngmres->gammaC) && (ngmres->gammaC > 2.)) ngmres->gammaC = ngmres->gammaA;
137: /* set the default type of the line search if the user hasn't already. */
138: if (!snes->linesearch) {
139: SNESGetLineSearch(snes,&linesearch);
140: SNESLineSearchSetType(linesearch,SNESLINESEARCHBASIC);
141: }
142: return(0);
143: }
147: PetscErrorCode SNESView_NGMRES(SNES snes,PetscViewer viewer)
148: {
149: SNES_NGMRES *ngmres = (SNES_NGMRES*) snes->data;
150: PetscBool iascii;
154: PetscObjectTypeCompare((PetscObject) viewer,PETSCVIEWERASCII,&iascii);
155: if (iascii) {
156: PetscViewerASCIIPrintf(viewer," Number of stored past updates: %d\n", ngmres->msize);
157: PetscViewerASCIIPrintf(viewer," Residual selection: gammaA=%1.0e, gammaC=%1.0e\n",ngmres->gammaA,ngmres->gammaC);
158: PetscViewerASCIIPrintf(viewer," Difference restart: epsilonB=%1.0e, deltaB=%1.0e\n",ngmres->epsilonB,ngmres->deltaB);
159: PetscViewerASCIIPrintf(viewer," Restart on F_M residual increase: %s\n",ngmres->restart_fm_rise?"TRUE":"FALSE");
160: }
161: return(0);
162: }
166: PetscErrorCode SNESSolve_NGMRES(SNES snes)
167: {
168: SNES_NGMRES *ngmres = (SNES_NGMRES*) snes->data;
169: /* present solution, residual, and preconditioned residual */
170: Vec X,F,B,D,Y;
172: /* candidate linear combination answers */
173: Vec XA,FA,XM,FM;
175: /* coefficients and RHS to the minimization problem */
176: PetscReal fnorm,fMnorm,fAnorm;
177: PetscReal xnorm,xMnorm,xAnorm;
178: PetscReal ynorm,yMnorm,yAnorm;
179: PetscInt k,k_restart,l,ivec,restart_count = 0;
181: /* solution selection data */
182: PetscBool selectRestart;
183: /*
184: These two variables are initialized to prevent compilers/analyzers from producing false warnings about these variables being passed
185: to SNESNGMRESSelect_Private() without being set when SNES_NGMRES_RESTART_DIFFERENCE, the values are not used in the subroutines in that case
186: so the code is correct as written.
187: */
188: PetscReal dnorm = 0.0,dminnorm = 0.0;
189: PetscReal fminnorm;
191: SNESConvergedReason reason;
192: SNESLineSearchReason lssucceed;
193: PetscErrorCode ierr;
196: if (snes->xl || snes->xu || snes->ops->computevariablebounds) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE, "SNES solver %s does not support bounds", ((PetscObject)snes)->type_name);
198: PetscCitationsRegister(SNESCitation,&SNEScite);
199: /* variable initialization */
200: snes->reason = SNES_CONVERGED_ITERATING;
201: X = snes->vec_sol;
202: F = snes->vec_func;
203: B = snes->vec_rhs;
204: XA = snes->vec_sol_update;
205: FA = snes->work[0];
206: D = snes->work[1];
208: /* work for the line search */
209: Y = snes->work[2];
210: XM = snes->work[3];
211: FM = snes->work[4];
213: PetscObjectSAWsTakeAccess((PetscObject)snes);
214: snes->iter = 0;
215: snes->norm = 0.;
216: PetscObjectSAWsGrantAccess((PetscObject)snes);
218: /* initialization */
220: if (snes->pc && snes->pcside == PC_LEFT) {
221: SNESApplyNPC(snes,X,NULL,F);
222: SNESGetConvergedReason(snes->pc,&reason);
223: if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
224: snes->reason = SNES_DIVERGED_INNER;
225: return(0);
226: }
227: VecNorm(F,NORM_2,&fnorm);
228: } else {
229: if (!snes->vec_func_init_set) {
230: SNESComputeFunction(snes,X,F);
231: } else snes->vec_func_init_set = PETSC_FALSE;
233: VecNorm(F,NORM_2,&fnorm);
234: SNESCheckFunctionNorm(snes,fnorm);
235: }
236: fminnorm = fnorm;
238: PetscObjectSAWsTakeAccess((PetscObject)snes);
239: snes->norm = fnorm;
240: PetscObjectSAWsGrantAccess((PetscObject)snes);
241: SNESLogConvergenceHistory(snes,fnorm,0);
242: SNESMonitor(snes,0,fnorm);
243: (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);
244: if (snes->reason) return(0);
245: SNESNGMRESUpdateSubspace_Private(snes,0,0,F,fnorm,X);
247: k_restart = 1;
248: l = 1;
249: ivec = 0;
250: for (k=1; k < snes->max_its+1; k++) {
251: /* Computation of x^M */
252: if (snes->pc && snes->pcside == PC_RIGHT) {
253: VecCopy(X,XM);
254: SNESSetInitialFunction(snes->pc,F);
256: PetscLogEventBegin(SNES_NPCSolve,snes->pc,XM,B,0);
257: SNESSolve(snes->pc,B,XM);
258: PetscLogEventEnd(SNES_NPCSolve,snes->pc,XM,B,0);
260: SNESGetConvergedReason(snes->pc,&reason);
261: if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
262: snes->reason = SNES_DIVERGED_INNER;
263: return(0);
264: }
265: SNESGetNPCFunction(snes,FM,&fMnorm);
266: } else {
267: /* no preconditioner -- just take gradient descent with line search */
268: VecCopy(F,Y);
269: VecCopy(F,FM);
270: VecCopy(X,XM);
272: fMnorm = fnorm;
274: SNESLineSearchApply(snes->linesearch,XM,FM,&fMnorm,Y);
275: SNESLineSearchGetReason(snes->linesearch,&lssucceed);
276: if (lssucceed) {
277: if (++snes->numFailures >= snes->maxFailures) {
278: snes->reason = SNES_DIVERGED_LINE_SEARCH;
279: return(0);
280: }
281: }
282: }
284: SNESNGMRESFormCombinedSolution_Private(snes,ivec,l,XM,FM,fMnorm,X,XA,FA);
285: /* r = F(x) */
286: if (fminnorm > fMnorm) fminnorm = fMnorm; /* the minimum norm is now of F^M */
288: /* differences for selection and restart */
289: if (ngmres->restart_type == SNES_NGMRES_RESTART_DIFFERENCE || ngmres->select_type == SNES_NGMRES_SELECT_DIFFERENCE) {
290: SNESNGMRESNorms_Private(snes,l,X,F,XM,FM,XA,FA,D,&dnorm,&dminnorm,&xMnorm,NULL,&yMnorm,&xAnorm,&fAnorm,&yAnorm);
291: } else {
292: SNESNGMRESNorms_Private(snes,l,X,F,XM,FM,XA,FA,D,NULL,NULL,&xMnorm,NULL,&yMnorm,&xAnorm,&fAnorm,&yAnorm);
293: }
294: SNESCheckFunctionNorm(snes,fnorm);
296: /* combination (additive) or selection (multiplicative) of the N-GMRES solution */
297: SNESNGMRESSelect_Private(snes,k_restart,XM,FM,xMnorm,fMnorm,yMnorm,XA,FA,xAnorm,fAnorm,yAnorm,dnorm,fminnorm,dminnorm,X,F,Y,&xnorm,&fnorm,&ynorm);
298: selectRestart = PETSC_FALSE;
300: if (ngmres->restart_type == SNES_NGMRES_RESTART_DIFFERENCE) {
301: SNESNGMRESSelectRestart_Private(snes,l,fMnorm,fAnorm,dnorm,fminnorm,dminnorm,&selectRestart);
303: /* if the restart conditions persist for more than restart_it iterations, restart. */
304: if (selectRestart) restart_count++;
305: else restart_count = 0;
306: } else if (ngmres->restart_type == SNES_NGMRES_RESTART_PERIODIC) {
307: if (k_restart > ngmres->restart_periodic) {
308: if (ngmres->monitor) PetscViewerASCIIPrintf(ngmres->monitor,"periodic restart after %D iterations\n",k_restart);
309: restart_count = ngmres->restart_it;
310: }
311: }
313: ivec = k_restart % ngmres->msize; /* replace the last used part of the subspace */
315: /* restart after restart conditions have persisted for a fixed number of iterations */
316: if (restart_count >= ngmres->restart_it) {
317: if (ngmres->monitor) {
318: PetscViewerASCIIPrintf(ngmres->monitor,"Restarted at iteration %d\n",k_restart);
319: }
320: restart_count = 0;
321: k_restart = 1;
322: l = 1;
323: ivec = 0;
324: /* q_{00} = nu */
325: SNESNGMRESUpdateSubspace_Private(snes,0,0,FM,fMnorm,XM);
326: } else {
327: /* select the current size of the subspace */
328: if (l < ngmres->msize) l++;
329: k_restart++;
330: /* place the current entry in the list of previous entries */
331: if (ngmres->candidate) {
332: if (fminnorm > fMnorm) fminnorm = fMnorm;
333: SNESNGMRESUpdateSubspace_Private(snes,ivec,l,FM,fMnorm,XM);
334: } else {
335: if (fminnorm > fnorm) fminnorm = fnorm;
336: SNESNGMRESUpdateSubspace_Private(snes,ivec,l,F,fnorm,X);
337: }
338: }
340: PetscObjectSAWsTakeAccess((PetscObject)snes);
341: snes->iter = k;
342: snes->norm = fnorm;
343: PetscObjectSAWsGrantAccess((PetscObject)snes);
344: SNESLogConvergenceHistory(snes,snes->norm,snes->iter);
345: SNESMonitor(snes,snes->iter,snes->norm);
346: (*snes->ops->converged)(snes,snes->iter,0,0,fnorm,&snes->reason,snes->cnvP);
347: if (snes->reason) return(0);
348: }
349: snes->reason = SNES_DIVERGED_MAX_IT;
350: return(0);
351: }
355: /*@
356: SNESNGMRESSetRestartFmRise - Increase the restart count if the step x_M increases the residual F_M
358: Input Parameters:
359: + snes - the SNES context.
360: - flg - boolean value deciding whether to use the option or not
362: Options Database:
363: + -snes_ngmres_restart_fm_rise - Increase the restart count if the step x_M increases the residual F_M
365: Level: intermediate
367: Notes:
368: If the proposed step x_M increases the residual F_M, it might be trying to get out of a stagnation area.
369: To help the solver do that, reset the Krylov subspace whenever F_M increases.
371: This option must be used with SNES_NGMRES_RESTART_DIFFERENCE
373: The default is FALSE.
374: .seealso: SNES_NGMRES_RESTART_DIFFERENCE
375: @*/
376: PetscErrorCode SNESNGMRESSetRestartFmRise(SNES snes,PetscBool flg)
377: {
378: PetscErrorCode (*f)(SNES,PetscBool);
382: PetscObjectQueryFunction((PetscObject)snes,"SNESNGMRESSetRestartFmRise_C",&f);
383: if (f) {(f)(snes,flg);}
384: return(0);
385: }
389: PetscErrorCode SNESNGMRESSetRestartFmRise_NGMRES(SNES snes,PetscBool flg)
390: {
391: SNES_NGMRES *ngmres = (SNES_NGMRES*)snes->data;
394: ngmres->restart_fm_rise = flg;
395: return(0);
396: }
400: PetscErrorCode SNESNGMRESGetRestartFmRise(SNES snes,PetscBool *flg)
401: {
402: PetscErrorCode (*f)(SNES,PetscBool*);
406: PetscObjectQueryFunction((PetscObject)snes,"SNESNGMRESGetRestartFmRise_C",&f);
407: if (f) {(f)(snes,flg);}
408: return(0);
409: }
413: PetscErrorCode SNESNGMRESGetRestartFmRise_NGMRES(SNES snes,PetscBool *flg)
414: {
415: SNES_NGMRES *ngmres = (SNES_NGMRES*)snes->data;
418: *flg = ngmres->restart_fm_rise;
419: return(0);
420: }
425: /*@
426: SNESNGMRESSetRestartType - Sets the restart type for SNESNGMRES.
428: Logically Collective on SNES
430: Input Parameters:
431: + snes - the iterative context
432: - rtype - restart type
434: Options Database:
435: + -snes_ngmres_restart_type<difference,periodic,none> - set the restart type
436: - -snes_ngmres_restart[30] - sets the number of iterations before restart for periodic
438: Level: intermediate
440: SNESNGMRESRestartTypes:
441: + SNES_NGMRES_RESTART_NONE - never restart
442: . SNES_NGMRES_RESTART_DIFFERENCE - restart based upon difference criteria
443: - SNES_NGMRES_RESTART_PERIODIC - restart after a fixed number of iterations
445: Notes:
446: The default line search used is the L2 line search and it requires two additional function evaluations.
448: .keywords: SNES, SNESNGMRES, restart, type, set SNESLineSearch
449: @*/
450: PetscErrorCode SNESNGMRESSetRestartType(SNES snes,SNESNGMRESRestartType rtype)
451: {
456: PetscTryMethod(snes,"SNESNGMRESSetRestartType_C",(SNES,SNESNGMRESRestartType),(snes,rtype));
457: return(0);
458: }
462: /*@
463: SNESNGMRESSetSelectType - Sets the selection type for SNESNGMRES. This determines how the candidate solution and
464: combined solution are used to create the next iterate.
466: Logically Collective on SNES
468: Input Parameters:
469: + snes - the iterative context
470: - stype - selection type
472: Options Database:
473: . -snes_ngmres_select_type<difference,none,linesearch>
475: Level: intermediate
477: SNESNGMRESSelectTypes:
478: + SNES_NGMRES_SELECT_NONE - choose the combined solution all the time
479: . SNES_NGMRES_SELECT_DIFFERENCE - choose based upon the selection criteria
480: - SNES_NGMRES_SELECT_LINESEARCH - choose based upon line search combination
482: Notes:
483: The default line search used is the L2 line search and it requires two additional function evaluations.
485: .keywords: SNES, SNESNGMRES, selection, type, set SNESLineSearch
486: @*/
487: PetscErrorCode SNESNGMRESSetSelectType(SNES snes,SNESNGMRESSelectType stype)
488: {
493: PetscTryMethod(snes,"SNESNGMRESSetSelectType_C",(SNES,SNESNGMRESSelectType),(snes,stype));
494: return(0);
495: }
499: PetscErrorCode SNESNGMRESSetSelectType_NGMRES(SNES snes,SNESNGMRESSelectType stype)
500: {
501: SNES_NGMRES *ngmres = (SNES_NGMRES*)snes->data;
504: ngmres->select_type = stype;
505: return(0);
506: }
510: PetscErrorCode SNESNGMRESSetRestartType_NGMRES(SNES snes,SNESNGMRESRestartType rtype)
511: {
512: SNES_NGMRES *ngmres = (SNES_NGMRES*)snes->data;
515: ngmres->restart_type = rtype;
516: return(0);
517: }
519: /*MC
520: SNESNGMRES - The Nonlinear Generalized Minimum Residual method.
522: Level: beginner
524: Options Database:
525: + -snes_ngmres_select_type<difference,none,linesearch> - choose the select between candidate and combined solution
526: . -snes_ngmres_restart_type<difference,none,periodic> - choose the restart conditions
527: . -snes_ngmres_candidate - Use NGMRES variant which combines candidate solutions instead of actual solutions
528: . -snes_ngmres_m - Number of stored previous solutions and residuals
529: . -snes_ngmres_restart_it - Number of iterations the restart conditions hold before restart
530: . -snes_ngmres_gammaA - Residual tolerance for solution select between the candidate and combination
531: . -snes_ngmres_gammaC - Residual tolerance for restart
532: . -snes_ngmres_epsilonB - Difference tolerance between subsequent solutions triggering restart
533: . -snes_ngmres_deltaB - Difference tolerance between residuals triggering restart
534: . -snes_ngmres_restart_fm_rise - Restart on residual rise from x_M step
535: . -snes_ngmres_monitor - Prints relevant information about the ngmres iteration
536: . -snes_linesearch_type <basic,l2,cp> - Line search type used for the default smoother
537: - -additive_snes_linesearch_type - linesearch type used to select between the candidate and combined solution with additive select type
539: Notes:
541: The N-GMRES method combines m previous solutions into a minimum-residual solution by solving a small linearized
542: optimization problem at each iteration.
544: Very similar to the SNESANDERSON algorithm.
546: References:
547: + 1. - C. W. Oosterlee and T. Washio, "Krylov Subspace Acceleration of Nonlinear Multigrid with Application to Recirculating Flows",
548: SIAM Journal on Scientific Computing, 21(5), 2000.
549: - 2. - Peter R. Brune, Matthew G. Knepley, Barry F. Smith, and Xuemin Tu, "Composing Scalable Nonlinear Algebraic Solvers",
550: SIAM Review, 57(4), 2015
553: .seealso: SNESCreate(), SNES, SNESSetType(), SNESType (for list of available types)
554: M*/
558: PETSC_EXTERN PetscErrorCode SNESCreate_NGMRES(SNES snes)
559: {
560: SNES_NGMRES *ngmres;
564: snes->ops->destroy = SNESDestroy_NGMRES;
565: snes->ops->setup = SNESSetUp_NGMRES;
566: snes->ops->setfromoptions = SNESSetFromOptions_NGMRES;
567: snes->ops->view = SNESView_NGMRES;
568: snes->ops->solve = SNESSolve_NGMRES;
569: snes->ops->reset = SNESReset_NGMRES;
571: snes->usespc = PETSC_TRUE;
572: snes->usesksp = PETSC_FALSE;
573: snes->pcside = PC_RIGHT;
575: PetscNewLog(snes,&ngmres);
576: snes->data = (void*) ngmres;
577: ngmres->msize = 30;
579: if (!snes->tolerancesset) {
580: snes->max_funcs = 30000;
581: snes->max_its = 10000;
582: }
584: ngmres->candidate = PETSC_FALSE;
586: ngmres->additive_linesearch = NULL;
587: ngmres->approxfunc = PETSC_FALSE;
588: ngmres->restart_it = 2;
589: ngmres->restart_periodic = 30;
590: ngmres->gammaA = 2.0;
591: ngmres->gammaC = 2.0;
592: ngmres->deltaB = 0.9;
593: ngmres->epsilonB = 0.1;
594: ngmres->restart_fm_rise = PETSC_FALSE;
596: ngmres->restart_type = SNES_NGMRES_RESTART_DIFFERENCE;
597: ngmres->select_type = SNES_NGMRES_SELECT_DIFFERENCE;
599: PetscObjectComposeFunction((PetscObject)snes,"SNESNGMRESSetSelectType_C",SNESNGMRESSetSelectType_NGMRES);
600: PetscObjectComposeFunction((PetscObject)snes,"SNESNGMRESSetRestartType_C",SNESNGMRESSetRestartType_NGMRES);
601: PetscObjectComposeFunction((PetscObject)snes,"SNESNGMRESSetRestartFmRise_C",SNESNGMRESSetRestartFmRise_NGMRES);
602: PetscObjectComposeFunction((PetscObject)snes,"SNESNGMRESGetRestartFmRise_C",SNESNGMRESGetRestartFmRise_NGMRES);
603: return(0);
604: }