Actual source code: gmres.c

  1: /*$Id: gmres.c,v 1.176 2001/08/07 03:03:51 balay Exp $*/

  3: /*
  4:     This file implements GMRES (a Generalized Minimal Residual) method.  
  5:     Reference:  Saad and Schultz, 1986.


  8:     Some comments on left vs. right preconditioning, and restarts.
  9:     Left and right preconditioning.
 10:     If right preconditioning is chosen, then the problem being solved
 11:     by gmres is actually
 12:        My =  AB^-1 y = f
 13:     so the initial residual is 
 14:           r = f - Mx
 15:     Note that B^-1 y = x or y = B x, and if x is non-zero, the initial
 16:     residual is
 17:           r = f - A x
 18:     The final solution is then
 19:           x = B^-1 y 

 21:     If left preconditioning is chosen, then the problem being solved is
 22:        My = B^-1 A x = B^-1 f,
 23:     and the initial residual is
 24:        r  = B^-1(f - Ax)

 26:     Restarts:  Restarts are basically solves with x0 not equal to zero.
 27:     Note that we can eliminate an extra application of B^-1 between
 28:     restarts as long as we don't require that the solution at the end
 29:     of an unsuccessful gmres iteration always be the solution x.
 30:  */

 32:  #include src/sles/ksp/impls/gmres/gmresp.h
 33: #define GMRES_DELTA_DIRECTIONS 10
 34: #define GMRES_DEFAULT_MAXK     30
 35: static int    GMRESGetNewVectors(KSP,int);
 36: static int    GMRESUpdateHessenberg(KSP,int,PetscTruth,PetscReal*);
 37: static int    BuildGmresSoln(PetscScalar*,Vec,Vec,KSP,int);

 41: int    KSPSetUp_GMRES(KSP ksp)
 42: {
 43:   unsigned  int size,hh,hes,rs,cc;
 44:   int       ierr,max_k,k;
 45:   KSP_GMRES *gmres = (KSP_GMRES *)ksp->data;

 48:   if (ksp->pc_side == PC_SYMMETRIC) {
 49:     SETERRQ(2,"no symmetric preconditioning for KSPGMRES");
 50:   }

 52:   max_k         = gmres->max_k;
 53:   hh            = (max_k + 2) * (max_k + 1);
 54:   hes           = (max_k + 1) * (max_k + 1);
 55:   rs            = (max_k + 2);
 56:   cc            = (max_k + 1);
 57:   size          = (hh + hes + rs + 2*cc) * sizeof(PetscScalar);

 59:   PetscMalloc(size,&gmres->hh_origin);
 60:   PetscMemzero(gmres->hh_origin,size);
 61:   PetscLogObjectMemory(ksp,size);
 62:   gmres->hes_origin = gmres->hh_origin + hh;
 63:   gmres->rs_origin  = gmres->hes_origin + hes;
 64:   gmres->cc_origin  = gmres->rs_origin + rs;
 65:   gmres->ss_origin  = gmres->cc_origin + cc;

 67:   if (ksp->calc_sings) {
 68:     /* Allocate workspace to hold Hessenberg matrix needed by Eispack */
 69:     size = (max_k + 3)*(max_k + 9)*sizeof(PetscScalar);
 70:     PetscMalloc(size,&gmres->Rsvd);
 71:     PetscMalloc(5*(max_k+2)*sizeof(PetscReal),&gmres->Dsvd);
 72:     PetscLogObjectMemory(ksp,size+5*(max_k+2)*sizeof(PetscReal));
 73:   }

 75:   /* Allocate array to hold pointers to user vectors.  Note that we need
 76:    4 + max_k + 1 (since we need it+1 vectors, and it <= max_k) */
 77:   PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&gmres->vecs);
 78:   gmres->vecs_allocated = VEC_OFFSET + 2 + max_k;
 79:   PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(void *),&gmres->user_work);
 80:   PetscMalloc((VEC_OFFSET+2+max_k)*sizeof(int),&gmres->mwork_alloc);
 81:   PetscLogObjectMemory(ksp,(VEC_OFFSET+2+max_k)*(2*sizeof(void *)+sizeof(int)));

 83:   if (gmres->q_preallocate) {
 84:     gmres->vv_allocated   = VEC_OFFSET + 2 + max_k;
 85:     VecDuplicateVecs(VEC_RHS,gmres->vv_allocated,&gmres->user_work[0]);
 86:     PetscLogObjectParents(ksp,gmres->vv_allocated,gmres->user_work[0]);
 87:     gmres->mwork_alloc[0] = gmres->vv_allocated;
 88:     gmres->nwork_alloc    = 1;
 89:     for (k=0; k<gmres->vv_allocated; k++) {
 90:       gmres->vecs[k] = gmres->user_work[0][k];
 91:     }
 92:   } else {
 93:     gmres->vv_allocated    = 5;
 94:     VecDuplicateVecs(ksp->vec_rhs,5,&gmres->user_work[0]);
 95:     PetscLogObjectParents(ksp,5,gmres->user_work[0]);
 96:     gmres->mwork_alloc[0]  = 5;
 97:     gmres->nwork_alloc     = 1;
 98:     for (k=0; k<gmres->vv_allocated; k++) {
 99:       gmres->vecs[k] = gmres->user_work[0][k];
100:     }
101:   }
102:   return(0);
103: }

105: /*
106:     Run gmres, possibly with restart.  Return residual history if requested.
107:     input parameters:

109: .        gmres  - structure containing parameters and work areas

111:     output parameters:
112: .        nres    - residuals (from preconditioned system) at each step.
113:                   If restarting, consider passing nres+it.  If null, 
114:                   ignored
115: .        itcount - number of iterations used.  nres[0] to nres[itcount]
116:                   are defined.  If null, ignored.
117:                   
118:     Notes:
119:     On entry, the value in vector VEC_VV(0) should be the initial residual
120:     (this allows shortcuts where the initial preconditioned residual is 0).
121:  */
124: int GMREScycle(int *itcount,KSP ksp)
125: {
126:   KSP_GMRES    *gmres = (KSP_GMRES *)(ksp->data);
127:   PetscReal    res_norm,res,hapbnd,tt;
128:   int          ierr,it = 0, max_k = gmres->max_k,max_it = ksp->max_it;
129:   PetscTruth   hapend = PETSC_FALSE;

132:   VecNormalize(VEC_VV(0),&res_norm);
133:   res     = res_norm;
134:   *GRS(0) = res_norm;

136:   /* check for the convergence */
137:   if (!res) {
138:     if (itcount) *itcount = 0;
139:     ksp->reason = KSP_CONVERGED_ATOL;
140:     PetscLogInfo(ksp,"GMRESCycle: Converged due to zero residual norm on entry\n");
141:     return(0);
142:   }

144:   PetscObjectTakeAccess(ksp);
145:   ksp->rnorm = res;
146:   PetscObjectGrantAccess(ksp);
147:   gmres->it = (it - 1);
148:   (*ksp->converged)(ksp,ksp->its,res,&ksp->reason,ksp->cnvP);
149:   while (!ksp->reason && it < max_k && ksp->its < max_it) {
150:     KSPLogResidualHistory(ksp,res);
151:     gmres->it = (it - 1);
152:     KSPMonitor(ksp,ksp->its,res);
153:     if (gmres->vv_allocated <= it + VEC_OFFSET + 1) {
154:       GMRESGetNewVectors(ksp,it+1);
155:     }
156:     KSP_PCApplyBAorAB(ksp,ksp->B,ksp->pc_side,VEC_VV(it),VEC_VV(1+it),VEC_TEMP_MATOP);

158:     /* update hessenberg matrix and do Gram-Schmidt */
159:     (*gmres->orthog)(ksp,it);

161:     /* vv(i+1) . vv(i+1) */
162:     VecNormalize(VEC_VV(it+1),&tt);
163:     /* save the magnitude */
164:     *HH(it+1,it)    = tt;
165:     *HES(it+1,it)   = tt;

167:     /* check for the happy breakdown */
168:     hapbnd  = PetscAbsScalar(tt / *GRS(it));
169:     if (hapbnd > gmres->haptol) hapbnd = gmres->haptol;
170:     if (tt < hapbnd) {
171:       PetscLogInfo(ksp,"Detected happy breakdown, current hapbnd = %g tt = %g\n",hapbnd,tt);
172:       hapend = PETSC_TRUE;
173:     }
174:     GMRESUpdateHessenberg(ksp,it,hapend,&res);
175:     it++;
176:     gmres->it  = (it-1);  /* For converged */
177:     PetscObjectTakeAccess(ksp);
178:     ksp->its++;
179:     ksp->rnorm = res;
180:     PetscObjectGrantAccess(ksp);

182:     (*ksp->converged)(ksp,ksp->its,res,&ksp->reason,ksp->cnvP);

184:     /* Catch error in happy breakdown and signal convergence and break from loop */
185:     if (hapend) {
186:       if (!ksp->reason) {
187:         SETERRQ1(0,"You reached the happy break down, but convergence was not indicated. Residual norm = %g",res);
188:       }
189:       break;
190:     }
191:   }

193:   /* Monitor if we know that we will not return for a restart */
194:   if (ksp->reason || ksp->its >= max_it) {
195:     KSPLogResidualHistory(ksp,res);
196:     KSPMonitor(ksp,ksp->its,res);
197:   }

199:   if (itcount) *itcount    = it;


202:   /*
203:     Down here we have to solve for the "best" coefficients of the Krylov
204:     columns, add the solution values together, and possibly unwind the
205:     preconditioning from the solution
206:    */
207:   /* Form the solution (or the solution so far) */
208:   BuildGmresSoln(GRS(0),VEC_SOLN,VEC_SOLN,ksp,it-1);

210:   return(0);
211: }

215: int KSPSolve_GMRES(KSP ksp,int *outits)
216: {
217:   int        ierr,its,itcount;
218:   KSP_GMRES  *gmres = (KSP_GMRES *)ksp->data;
219:   PetscTruth guess_zero = ksp->guess_zero;

222:   if (ksp->calc_sings && !gmres->Rsvd) {
223:     SETERRQ(1,"Must call KSPSetComputeSingularValues() before KSPSetUp() is called");
224:   }

226:   PetscObjectTakeAccess(ksp);
227:   ksp->its = 0;
228:   PetscObjectGrantAccess(ksp);

230:   itcount     = 0;
231:   ksp->reason = KSP_CONVERGED_ITERATING;
232:   while (!ksp->reason) {
233:     KSPInitialResidual(ksp,VEC_SOLN,VEC_TEMP,VEC_TEMP_MATOP,VEC_VV(0),VEC_RHS);
234:     GMREScycle(&its,ksp);
235:     itcount += its;
236:     if (itcount >= ksp->max_it) {
237:       ksp->reason = KSP_DIVERGED_ITS;
238:       break;
239:     }
240:     ksp->guess_zero = PETSC_FALSE; /* every future call to KSPInitialResidual() will have nonzero guess */
241:   }
242:   ksp->guess_zero = guess_zero; /* restore if user provided nonzero initial guess */
243:   if (outits) *outits = itcount;
244:   return(0);
245: }

249: int KSPDestroy_GMRES_Internal(KSP ksp)
250: {
251:   KSP_GMRES *gmres = (KSP_GMRES*)ksp->data;
252:   int       i,ierr;

255:   /* Free the Hessenberg matrix */
256:   if (gmres->hh_origin) {PetscFree(gmres->hh_origin);}

258:   /* Free the pointer to user variables */
259:   if (gmres->vecs) {PetscFree(gmres->vecs);}

261:   /* free work vectors */
262:   for (i=0; i<gmres->nwork_alloc; i++) {
263:     VecDestroyVecs(gmres->user_work[i],gmres->mwork_alloc[i]);
264:   }
265:   if (gmres->user_work)  {PetscFree(gmres->user_work);}
266:   if (gmres->mwork_alloc) {PetscFree(gmres->mwork_alloc);}
267:   if (gmres->nrs) {PetscFree(gmres->nrs);}
268:   if (gmres->sol_temp) {VecDestroy(gmres->sol_temp);}
269:   if (gmres->Rsvd) {PetscFree(gmres->Rsvd);}
270:   if (gmres->Dsvd) {PetscFree(gmres->Dsvd);}

272:   return(0);
273: }

277: int KSPDestroy_GMRES(KSP ksp)
278: {
279:   KSP_GMRES *gmres = (KSP_GMRES*)ksp->data;
280:   int       ierr;

283:   KSPDestroy_GMRES_Internal(ksp);
284:   PetscFree(gmres);
285:   return(0);
286: }
287: /*
288:     BuildGmresSoln - create the solution from the starting vector and the
289:     current iterates.

291:     Input parameters:
292:         nrs - work area of size it + 1.
293:         vs  - index of initial guess
294:         vdest - index of result.  Note that vs may == vdest (replace
295:                 guess with the solution).

297:      This is an internal routine that knows about the GMRES internals.
298:  */
301: static int BuildGmresSoln(PetscScalar* nrs,Vec vs,Vec vdest,KSP ksp,int it)
302: {
303:   PetscScalar tt,zero = 0.0,one = 1.0;
304:   int         ierr,ii,k,j;
305:   KSP_GMRES   *gmres = (KSP_GMRES *)(ksp->data);

308:   /* Solve for solution vector that minimizes the residual */

310:   /* If it is < 0, no gmres steps have been performed */
311:   if (it < 0) {
312:     if (vdest != vs) {
313:       VecCopy(vs,vdest);
314:     }
315:     return(0);
316:   }
317:   if (*HH(it,it) == 0.0) SETERRQ2(1,"HH(it,it) is identically zero; it = %d GRS(it) = %g",it,PetscAbsScalar(*GRS(it)));
318:   if (*HH(it,it) != 0.0) {
319:     nrs[it] = *GRS(it) / *HH(it,it);
320:   } else {
321:     nrs[it] = 0.0;
322:   }
323:   for (ii=1; ii<=it; ii++) {
324:     k   = it - ii;
325:     tt  = *GRS(k);
326:     for (j=k+1; j<=it; j++) tt  = tt - *HH(k,j) * nrs[j];
327:     nrs[k]   = tt / *HH(k,k);
328:   }

330:   /* Accumulate the correction to the solution of the preconditioned problem in TEMP */
331:   VecSet(&zero,VEC_TEMP);
332:   VecMAXPY(it+1,nrs,VEC_TEMP,&VEC_VV(0));

334:   KSPUnwindPreconditioner(ksp,VEC_TEMP,VEC_TEMP_MATOP);
335:   /* add solution to previous solution */
336:   if (vdest != vs) {
337:     VecCopy(vs,vdest);
338:   }
339:   VecAXPY(&one,VEC_TEMP,vdest);
340:   return(0);
341: }
342: /*
343:    Do the scalar work for the orthogonalization.  Return new residual.
344:  */
347: static int GMRESUpdateHessenberg(KSP ksp,int it,PetscTruth hapend,PetscReal *res)
348: {
349:   PetscScalar *hh,*cc,*ss,tt;
350:   int         j;
351:   KSP_GMRES   *gmres = (KSP_GMRES *)(ksp->data);

354:   hh  = HH(0,it);
355:   cc  = CC(0);
356:   ss  = SS(0);

358:   /* Apply all the previously computed plane rotations to the new column
359:      of the Hessenberg matrix */
360:   for (j=1; j<=it; j++) {
361:     tt  = *hh;
362: #if defined(PETSC_USE_COMPLEX)
363:     *hh = PetscConj(*cc) * tt + *ss * *(hh+1);
364: #else
365:     *hh = *cc * tt + *ss * *(hh+1);
366: #endif
367:     hh++;
368:     *hh = *cc++ * *hh - (*ss++ * tt);
369:   }

371:   /*
372:     compute the new plane rotation, and apply it to:
373:      1) the right-hand-side of the Hessenberg system
374:      2) the new column of the Hessenberg matrix
375:     thus obtaining the updated value of the residual
376:   */
377:   if (!hapend) {
378: #if defined(PETSC_USE_COMPLEX)
379:     tt        = PetscSqrtScalar(PetscConj(*hh) * *hh + PetscConj(*(hh+1)) * *(hh+1));
380: #else
381:     tt        = PetscSqrtScalar(*hh * *hh + *(hh+1) * *(hh+1));
382: #endif
383:     if (tt == 0.0) {SETERRQ(PETSC_ERR_KSP_BRKDWN,"Your matrix or preconditioner is the null operator");}
384:     *cc       = *hh / tt;
385:     *ss       = *(hh+1) / tt;
386:     *GRS(it+1) = - (*ss * *GRS(it));
387: #if defined(PETSC_USE_COMPLEX)
388:     *GRS(it)   = PetscConj(*cc) * *GRS(it);
389:     *hh       = PetscConj(*cc) * *hh + *ss * *(hh+1);
390: #else
391:     *GRS(it)   = *cc * *GRS(it);
392:     *hh       = *cc * *hh + *ss * *(hh+1);
393: #endif
394:     *res      = PetscAbsScalar(*GRS(it+1));
395:   } else {
396:     /* happy breakdown: HH(it+1, it) = 0, therfore we don't need to apply 
397:             another rotation matrix (so RH doesn't change).  The new residual is 
398:             always the new sine term times the residual from last time (GRS(it)), 
399:             but now the new sine rotation would be zero...so the residual should
400:             be zero...so we will multiply "zero" by the last residual.  This might
401:             not be exactly what we want to do here -could just return "zero". */
402: 
403:     *res = 0.0;
404:   }
405:   return(0);
406: }
407: /*
408:    This routine allocates more work vectors, starting from VEC_VV(it).
409:  */
412: static int GMRESGetNewVectors(KSP ksp,int it)
413: {
414:   KSP_GMRES *gmres = (KSP_GMRES *)ksp->data;
415:   int       nwork = gmres->nwork_alloc,k,nalloc,ierr;

418:   nalloc = gmres->delta_allocate;
419:   /* Adjust the number to allocate to make sure that we don't exceed the
420:     number of available slots */
421:   if (it + VEC_OFFSET + nalloc >= gmres->vecs_allocated){
422:     nalloc = gmres->vecs_allocated - it - VEC_OFFSET;
423:   }
424:   if (!nalloc) return(0);

426:   gmres->vv_allocated += nalloc;
427:   VecDuplicateVecs(ksp->vec_rhs,nalloc,&gmres->user_work[nwork]);
428:   PetscLogObjectParents(ksp,nalloc,gmres->user_work[nwork]);
429:   gmres->mwork_alloc[nwork] = nalloc;
430:   for (k=0; k<nalloc; k++) {
431:     gmres->vecs[it+VEC_OFFSET+k] = gmres->user_work[nwork][k];
432:   }
433:   gmres->nwork_alloc++;
434:   return(0);
435: }

439: int KSPBuildSolution_GMRES(KSP ksp,Vec  ptr,Vec *result)
440: {
441:   KSP_GMRES *gmres = (KSP_GMRES *)ksp->data;
442:   int       ierr;

445:   if (!ptr) {
446:     if (!gmres->sol_temp) {
447:       VecDuplicate(ksp->vec_sol,&gmres->sol_temp);
448:       PetscLogObjectParent(ksp,gmres->sol_temp);
449:     }
450:     ptr = gmres->sol_temp;
451:   }
452:   if (!gmres->nrs) {
453:     /* allocate the work area */
454:     PetscMalloc(gmres->max_k*sizeof(PetscScalar),&gmres->nrs);
455:     PetscLogObjectMemory(ksp,gmres->max_k*sizeof(PetscScalar));
456:   }

458:   BuildGmresSoln(gmres->nrs,VEC_SOLN,ptr,ksp,gmres->it);
459:   *result = ptr;
460:   return(0);
461: }

465: int KSPView_GMRES(KSP ksp,PetscViewer viewer)
466: {
467:   KSP_GMRES  *gmres = (KSP_GMRES *)ksp->data;
468:   char       *cstr;
469:   int        ierr;
470:   PetscTruth isascii,isstring;

473:   PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&isascii);
474:   PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_STRING,&isstring);
475:   if (gmres->orthog == KSPGMRESUnmodifiedGramSchmidtOrthogonalization) {
476:     cstr = "Unmodified Gram-Schmidt Orthogonalization";
477:   } else if (gmres->orthog == KSPGMRESModifiedGramSchmidtOrthogonalization) {
478:     cstr = "Modified Gram-Schmidt Orthogonalization";
479:   } else if (gmres->orthog == KSPGMRESIROrthogonalization) {
480:     cstr = "Unmodified Gram-Schmidt + 1 step Iterative Refinement Orthogonalization";
481:   } else {
482:     cstr = "unknown orthogonalization";
483:   }
484:   if (isascii) {
485:     PetscViewerASCIIPrintf(viewer,"  GMRES: restart=%d, using %s\n",gmres->max_k,cstr);
486:     PetscViewerASCIIPrintf(viewer,"  GMRES: happy breakdown tolerance %g\n",gmres->haptol);
487:   } else if (isstring) {
488:     PetscViewerStringSPrintf(viewer,"%s restart %d",cstr,gmres->max_k);
489:   } else {
490:     SETERRQ1(1,"Viewer type %s not supported for KSP GMRES",((PetscObject)viewer)->type_name);
491:   }
492:   return(0);
493: }

497: /*@C
498:    KSPGMRESKrylovMonitor - Calls VecView() for each direction in the 
499:    GMRES accumulated Krylov space.

501:    Collective on KSP

503:    Input Parameters:
504: +  ksp - the KSP context
505: .  its - iteration number
506: .  fgnorm - 2-norm of residual (or gradient)
507: -  a viewers object created with PetscViewersCreate()

509:    Level: intermediate

511: .keywords: KSP, nonlinear, vector, monitor, view, Krylov space

513: .seealso: KSPSetMonitor(), KSPDefaultMonitor(), VecView(), PetscViewersCreate(), PetscViewersDestroy()
514: @*/
515: int KSPGMRESKrylovMonitor(KSP ksp,int its,PetscReal fgnorm,void *dummy)
516: {
517:   PetscViewers viewers = (PetscViewers)dummy;
518:   KSP_GMRES    *gmres = (KSP_GMRES*)ksp->data;
519:   int          ierr;
520:   Vec          x;
521:   PetscViewer  viewer;

524:   PetscViewersGetViewer(viewers,gmres->it+1,&viewer);
525:   PetscViewerSetType(viewer,PETSC_VIEWER_DRAW);

527:   x      = VEC_VV(gmres->it+1);
528:   VecView(x,viewer);

530:   return(0);
531: }

535: int KSPSetFromOptions_GMRES(KSP ksp)
536: {
537:   int        ierr,restart;
538:   PetscReal  haptol;
539:   KSP_GMRES  *gmres = (KSP_GMRES*)ksp->data;
540:   PetscTruth flg;

543:   PetscOptionsHead("KSP GMRES Options");
544:     PetscOptionsInt("-ksp_gmres_restart","Number of Krylov search directions","KSPGMRESSetRestart",gmres->max_k,&restart,&flg);
545:     if (flg) { KSPGMRESSetRestart(ksp,restart); }
546:     PetscOptionsReal("-ksp_gmres_haptol","Tolerance for exact convergence (happy ending)","KSPGMRESSetHapTol",gmres->haptol,&haptol,&flg);
547:     if (flg) { KSPGMRESSetHapTol(ksp,haptol); }
548:     PetscOptionsName("-ksp_gmres_preallocate","Preallocate Krylov vectors","KSPGMRESSetPreAllocateVectors",&flg);
549:     if (flg) {KSPGMRESSetPreAllocateVectors(ksp);}
550:     PetscOptionsLogicalGroupBegin("-ksp_gmres_unmodifiedgramschmidt","Classical (unmodified) Gram-Schmidt (fast)","KSPGMRESSetOrthogonalization",&flg);
551:     if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESUnmodifiedGramSchmidtOrthogonalization);}
552:     PetscOptionsLogicalGroup("-ksp_gmres_modifiedgramschmidt","Modified Gram-Schmidt (slow,more stable)","KSPGMRESSetOrthogonalization",&flg);
553:     if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESModifiedGramSchmidtOrthogonalization);}
554:     PetscOptionsLogicalGroupEnd("-ksp_gmres_irorthog","Classical Gram-Schmidt + iterative refinement","KSPGMRESSetOrthogonalization",&flg);
555:     if (flg) {KSPGMRESSetOrthogonalization(ksp,KSPGMRESIROrthogonalization);}
556:     PetscOptionsName("-ksp_gmres_krylov_monitor","Plot the Krylov directions","KSPSetMonitor",&flg);
557:     if (flg) {
558:       PetscViewers viewers;
559:       PetscViewersCreate(ksp->comm,&viewers);
560:       KSPSetMonitor(ksp,KSPGMRESKrylovMonitor,viewers,(int (*)(void*))PetscViewersDestroy);
561:     }
562:   PetscOptionsTail();
563:   return(0);
564: }

566: EXTERN int KSPComputeExtremeSingularValues_GMRES(KSP,PetscReal *,PetscReal *);
567: EXTERN int KSPComputeEigenvalues_GMRES(KSP,int,PetscReal *,PetscReal *,int *);


570: EXTERN_C_BEGIN
573: int KSPGMRESSetHapTol_GMRES(KSP ksp,double tol)
574: {
575:   KSP_GMRES *gmres = (KSP_GMRES *)ksp->data;

578:   if (tol < 0.0) SETERRQ(1,"Tolerance must be non-negative");
579:   gmres->haptol = tol;
580:   return(0);
581: }
582: EXTERN_C_END

584: EXTERN_C_BEGIN
587: int KSPGMRESSetRestart_GMRES(KSP ksp,int max_k)
588: {
589:   KSP_GMRES *gmres = (KSP_GMRES *)ksp->data;
590:   int       ierr;

593:   if (max_k < 1) SETERRQ(1,"Restart must be positive");
594:   if (!ksp->setupcalled) {
595:     gmres->max_k = max_k;
596:   } else if (gmres->max_k != max_k) {
597:      gmres->max_k = max_k;
598:      ksp->setupcalled = 0;
599:      /* free the data structures, then create them again */
600:      KSPDestroy_GMRES_Internal(ksp);
601:   }

603:   return(0);
604: }
605: EXTERN_C_END

607: EXTERN_C_BEGIN
610: int KSPGMRESSetOrthogonalization_GMRES(KSP ksp,int (*fcn)(KSP,int))
611: {
614:   ((KSP_GMRES *)ksp->data)->orthog = fcn;
615:   return(0);
616: }
617: EXTERN_C_END

619: EXTERN_C_BEGIN
622: int KSPGMRESSetPreAllocateVectors_GMRES(KSP ksp)
623: {
624:   KSP_GMRES *gmres;

627:   gmres = (KSP_GMRES *)ksp->data;
628:   gmres->q_preallocate = 1;
629:   return(0);
630: }
631: EXTERN_C_END

633: EXTERN_C_BEGIN
636: int KSPCreate_GMRES(KSP ksp)
637: {
638:   KSP_GMRES *gmres;
639:   int       ierr;

642:   PetscNew(KSP_GMRES,&gmres);
643:   PetscMemzero(gmres,sizeof(KSP_GMRES));
644:   PetscLogObjectMemory(ksp,sizeof(KSP_GMRES));
645:   ksp->data                              = (void*)gmres;
646:   ksp->ops->buildsolution                = KSPBuildSolution_GMRES;

648:   ksp->ops->setup                        = KSPSetUp_GMRES;
649:   ksp->ops->solve                        = KSPSolve_GMRES;
650:   ksp->ops->destroy                      = KSPDestroy_GMRES;
651:   ksp->ops->view                         = KSPView_GMRES;
652:   ksp->ops->setfromoptions               = KSPSetFromOptions_GMRES;
653:   ksp->ops->computeextremesingularvalues = KSPComputeExtremeSingularValues_GMRES;
654:   ksp->ops->computeeigenvalues           = KSPComputeEigenvalues_GMRES;

656:   PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetPreAllocateVectors_C",
657:                                     "KSPGMRESSetPreAllocateVectors_GMRES",
658:                                      KSPGMRESSetPreAllocateVectors_GMRES);
659:   PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetOrthogonalization_C",
660:                                     "KSPGMRESSetOrthogonalization_GMRES",
661:                                      KSPGMRESSetOrthogonalization_GMRES);
662:   PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetRestart_C",
663:                                     "KSPGMRESSetRestart_GMRES",
664:                                      KSPGMRESSetRestart_GMRES);
665:   PetscObjectComposeFunctionDynamic((PetscObject)ksp,"KSPGMRESSetHapTol_C",
666:                                     "KSPGMRESSetHapTol_GMRES",
667:                                      KSPGMRESSetHapTol_GMRES);

669:   gmres->haptol              = 1.0e-30;
670:   gmres->q_preallocate       = 0;
671:   gmres->delta_allocate      = GMRES_DELTA_DIRECTIONS;
672:   gmres->orthog              = KSPGMRESUnmodifiedGramSchmidtOrthogonalization;
673:   gmres->nrs                 = 0;
674:   gmres->sol_temp            = 0;
675:   gmres->max_k               = GMRES_DEFAULT_MAXK;
676:   gmres->Rsvd                = 0;
677:   return(0);
678: }
679: EXTERN_C_END