Actual source code: fcg.c

petsc-master 2019-06-22
Report Typos and Errors
  1: /*
  2:     This file implements the FCG (Flexible Conjugate Gradient) method

  4: */

  6:  #include <../src/ksp/ksp/impls/fcg/fcgimpl.h>
  7: extern PetscErrorCode KSPComputeExtremeSingularValues_CG(KSP,PetscReal*,PetscReal*);
  8: extern PetscErrorCode KSPComputeEigenvalues_CG(KSP,PetscInt,PetscReal*,PetscReal*,PetscInt*);

 10: #define KSPFCG_DEFAULT_MMAX 30          /* maximum number of search directions to keep */
 11: #define KSPFCG_DEFAULT_NPREALLOC 10     /* number of search directions to preallocate */
 12: #define KSPFCG_DEFAULT_VECB 5           /* number of search directions to allocate each time new direction vectors are needed */
 13: #define KSPFCG_DEFAULT_TRUNCSTRAT KSP_FCD_TRUNC_TYPE_NOTAY

 15: static PetscErrorCode KSPAllocateVectors_FCG(KSP ksp, PetscInt nvecsneeded, PetscInt chunksize)
 16: {
 17:   PetscErrorCode  ierr;
 18:   PetscInt        i;
 19:   KSP_FCG         *fcg = (KSP_FCG*)ksp->data;
 20:   PetscInt        nnewvecs, nvecsprev;

 23:   /* Allocate enough new vectors to add chunksize new vectors, reach nvecsneedtotal, or to reach mmax+1, whichever is smallest */
 24:   if (fcg->nvecs < PetscMin(fcg->mmax+1,nvecsneeded)){
 25:     nvecsprev = fcg->nvecs;
 26:     nnewvecs = PetscMin(PetscMax(nvecsneeded-fcg->nvecs,chunksize),fcg->mmax+1-fcg->nvecs);
 27:     KSPCreateVecs(ksp,nnewvecs,&fcg->pCvecs[fcg->nchunks],0,NULL);
 28:     PetscLogObjectParents((PetscObject)ksp,nnewvecs,fcg->pCvecs[fcg->nchunks]);
 29:     KSPCreateVecs(ksp,nnewvecs,&fcg->pPvecs[fcg->nchunks],0,NULL);
 30:     PetscLogObjectParents((PetscObject)ksp,nnewvecs,fcg->pPvecs[fcg->nchunks]);
 31:     fcg->nvecs += nnewvecs;
 32:     for (i=0;i<nnewvecs;++i){
 33:       fcg->Cvecs[nvecsprev + i] = fcg->pCvecs[fcg->nchunks][i];
 34:       fcg->Pvecs[nvecsprev + i] = fcg->pPvecs[fcg->nchunks][i];
 35:     }
 36:     fcg->chunksizes[fcg->nchunks] = nnewvecs;
 37:     ++fcg->nchunks;
 38:   }
 39:   return(0);
 40: }

 42: static PetscErrorCode    KSPSetUp_FCG(KSP ksp)
 43: {
 45:   KSP_FCG        *fcg = (KSP_FCG*)ksp->data;
 46:   PetscInt       maxit = ksp->max_it;
 47:   const PetscInt nworkstd = 2;


 51:   /* Allocate "standard" work vectors (not including the basis and transformed basis vectors) */
 52:   KSPSetWorkVecs(ksp,nworkstd);

 54:   /* Allocated space for pointers to additional work vectors
 55:    note that mmax is the number of previous directions, so we add 1 for the current direction,
 56:    and an extra 1 for the prealloc (which might be empty) */
 57:   PetscMalloc5(fcg->mmax+1,&fcg->Pvecs,fcg->mmax+1,&fcg->Cvecs,fcg->mmax+1,&fcg->pPvecs,fcg->mmax+1,&fcg->pCvecs,fcg->mmax+2,&fcg->chunksizes);
 58:   PetscLogObjectMemory((PetscObject)ksp,2*(fcg->mmax+1)*sizeof(Vec*) + 2*(fcg->mmax + 1)*sizeof(Vec**) + (fcg->mmax + 2)*sizeof(PetscInt));

 60:   /* If the requested number of preallocated vectors is greater than mmax reduce nprealloc */
 61:   if(fcg->nprealloc > fcg->mmax+1){
 62:     PetscInfo2(NULL,"Requested nprealloc=%d is greater than m_max+1=%d. Resetting nprealloc = m_max+1.\n",fcg->nprealloc, fcg->mmax+1);
 63:   }

 65:   /* Preallocate additional work vectors */
 66:   KSPAllocateVectors_FCG(ksp,fcg->nprealloc,fcg->nprealloc);
 67:   /*
 68:   If user requested computations of eigenvalues then allocate work
 69:   work space needed
 70:   */
 71:   if (ksp->calc_sings) {
 72:     /* get space to store tridiagonal matrix for Lanczos */
 73:     PetscMalloc4(maxit,&fcg->e,maxit,&fcg->d,maxit,&fcg->ee,maxit,&fcg->dd);
 74:     PetscLogObjectMemory((PetscObject)ksp,2*(maxit+1)*(sizeof(PetscScalar)+sizeof(PetscReal)));

 76:     ksp->ops->computeextremesingularvalues = KSPComputeExtremeSingularValues_CG;
 77:     ksp->ops->computeeigenvalues           = KSPComputeEigenvalues_CG;
 78:   }
 79:   return(0);
 80: }

 82: static PetscErrorCode KSPSolve_FCG(KSP ksp)
 83: {
 85:   PetscInt       i,k,idx,mi;
 86:   KSP_FCG        *fcg = (KSP_FCG*)ksp->data;
 87:   PetscScalar    alpha=0.0,beta = 0.0,dpi,s;
 88:   PetscReal      dp=0.0;
 89:   Vec            B,R,Z,X,Pcurr,Ccurr;
 90:   Mat            Amat,Pmat;
 91:   PetscInt       eigs = ksp->calc_sings; /* Variables for eigen estimation - START*/
 92:   PetscInt       stored_max_it = ksp->max_it;
 93:   PetscScalar    alphaold = 0,betaold = 1.0,*e = 0,*d = 0;/* Variables for eigen estimation  - FINISH */


 97: #define VecXDot(x,y,a) (((fcg->type) == (KSP_CG_HERMITIAN)) ? VecDot(x,y,a) : VecTDot(x,y,a))
 98: #define VecXMDot(a,b,c,d) (((fcg->type) == (KSP_CG_HERMITIAN)) ? VecMDot(a,b,c,d) : VecMTDot(a,b,c,d))

100:   X             = ksp->vec_sol;
101:   B             = ksp->vec_rhs;
102:   R             = ksp->work[0];
103:   Z             = ksp->work[1];

105:   PCGetOperators(ksp->pc,&Amat,&Pmat);
106:   if (eigs) {e = fcg->e; d = fcg->d; e[0] = 0.0; }
107:   /* Compute initial residual needed for convergence check*/
108:   ksp->its = 0;
109:   if (!ksp->guess_zero) {
110:     KSP_MatMult(ksp,Amat,X,R);
111:     VecAYPX(R,-1.0,B);                    /*   r <- b - Ax     */
112:   } else {
113:     VecCopy(B,R);                         /*   r <- b (x is 0) */
114:   }
115:   switch (ksp->normtype) {
116:     case KSP_NORM_PRECONDITIONED:
117:       KSP_PCApply(ksp,R,Z);               /*   z <- Br         */
118:       VecNorm(Z,NORM_2,&dp);              /*   dp <- dqrt(z'*z) = sqrt(e'*A'*B'*B*A*e)     */
119:       KSPCheckNorm(ksp,dp);
120:       break;
121:     case KSP_NORM_UNPRECONDITIONED:
122:       VecNorm(R,NORM_2,&dp);              /*   dp <- sqrt(r'*r) = sqrt(e'*A'*A*e)     */
123:       KSPCheckNorm(ksp,dp);
124:       break;
125:     case KSP_NORM_NATURAL:
126:       KSP_PCApply(ksp,R,Z);               /*   z <- Br         */
127:       VecXDot(R,Z,&s);
128:       KSPCheckDot(ksp,s);
129:       dp = PetscSqrtReal(PetscAbsScalar(s));                   /*   dp <- sqrt(r'*z) = sqrt(e'*A'*B*A*e)  */
130:       break;
131:     case KSP_NORM_NONE:
132:       dp = 0.0;
133:       break;
134:     default: SETERRQ1(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"%s",KSPNormTypes[ksp->normtype]);
135:   }

137:   /* Initial Convergence Check */
138:   KSPLogResidualHistory(ksp,dp);
139:   KSPMonitor(ksp,0,dp);
140:   ksp->rnorm = dp;
141:   if (ksp->normtype == KSP_NORM_NONE) {
142:     KSPConvergedSkip(ksp,0,dp,&ksp->reason,ksp->cnvP);
143:   } else {
144:     (*ksp->converged)(ksp,0,dp,&ksp->reason,ksp->cnvP);
145:   }
146:   if (ksp->reason) return(0);

148:   /* Apply PC if not already done for convergence check */
149:   if(ksp->normtype == KSP_NORM_UNPRECONDITIONED || ksp->normtype == KSP_NORM_NONE){
150:     KSP_PCApply(ksp,R,Z);               /*   z <- Br         */
151:   }

153:   i = 0;
154:   do {
155:     ksp->its = i+1;

157:     /*  If needbe, allocate a new chunk of vectors in P and C */
158:     KSPAllocateVectors_FCG(ksp,i+1,fcg->vecb);

160:     /* Note that we wrap around and start clobbering old vectors */
161:     idx = i % (fcg->mmax+1);
162:     Pcurr = fcg->Pvecs[idx];
163:     Ccurr = fcg->Cvecs[idx];

165:     /* number of old directions to orthogonalize against */
166:     switch(fcg->truncstrat){
167:       case KSP_FCD_TRUNC_TYPE_STANDARD:
168:         mi = fcg->mmax;
169:         break;
170:       case KSP_FCD_TRUNC_TYPE_NOTAY:
171:         mi = ((i-1) % fcg->mmax)+1;
172:         break;
173:       default:
174:         SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Unrecognized Truncation Strategy");
175:     }

177:     /* Compute a new column of P (Currently does not support modified G-S or iterative refinement)*/
178:     VecCopy(Z,Pcurr);

180:     {
181:       PetscInt l,ndots;

183:       l = PetscMax(0,i-mi);
184:       ndots = i-l;
185:       if (ndots){
186:         PetscInt    j;
187:         Vec         *Pold,  *Cold;
188:         PetscScalar *dots;

190:         PetscMalloc3(ndots,&dots,ndots,&Cold,ndots,&Pold);
191:         for(k=l,j=0;j<ndots;++k,++j){
192:           idx = k % (fcg->mmax+1);
193:           Cold[j] = fcg->Cvecs[idx];
194:           Pold[j] = fcg->Pvecs[idx];
195:         }
196:         VecXMDot(Z,ndots,Cold,dots);
197:         for(k=0;k<ndots;++k){
198:           dots[k] = -dots[k];
199:         }
200:         VecMAXPY(Pcurr,ndots,dots,Pold);
201:         PetscFree3(dots,Cold,Pold);
202:       }
203:     }

205:     /* Update X and R */
206:     betaold = beta;
207:     VecXDot(Pcurr,R,&beta);                 /*  beta <- pi'*r       */
208:     KSPCheckDot(ksp,beta);
209:     KSP_MatMult(ksp,Amat,Pcurr,Ccurr);      /*  w <- A*pi (stored in ci)   */
210:     VecXDot(Pcurr,Ccurr,&dpi);              /*  dpi <- pi'*w        */
211:     alphaold = alpha;
212:     alpha = beta / dpi;                                          /*  alpha <- beta/dpi    */
213:     VecAXPY(X,alpha,Pcurr);                 /*  x <- x + alpha * pi  */
214:     VecAXPY(R,-alpha,Ccurr);                /*  r <- r - alpha * wi  */

216:     /* Compute norm for convergence check */
217:     switch (ksp->normtype) {
218:       case KSP_NORM_PRECONDITIONED:
219:         KSP_PCApply(ksp,R,Z);               /*   z <- Br             */
220:         VecNorm(Z,NORM_2,&dp);              /*   dp <- sqrt(z'*z) = sqrt(e'*A'*B'*B*A*e)  */
221:         KSPCheckNorm(ksp,dp);
222:       break;
223:       case KSP_NORM_UNPRECONDITIONED:
224:         VecNorm(R,NORM_2,&dp);              /*   dp <- sqrt(r'*r) = sqrt(e'*A'*A*e)   */
225:         KSPCheckNorm(ksp,dp);
226:         break;
227:       case KSP_NORM_NATURAL:
228:         KSP_PCApply(ksp,R,Z);               /*   z <- Br             */
229:         VecXDot(R,Z,&s);
230:         KSPCheckDot(ksp,s);
231:         dp = PetscSqrtReal(PetscAbsScalar(s));                   /*   dp <- sqrt(r'*z) = sqrt(e'*A'*B*A*e)  */
232:         break;
233:       case KSP_NORM_NONE:
234:         dp = 0.0;
235:         break;
236:       default: SETERRQ1(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"%s",KSPNormTypes[ksp->normtype]);
237:     }

239:     /* Check for convergence */
240:     ksp->rnorm = dp;
241:     KSPLogResidualHistory(ksp,dp);
242:     KSPMonitor(ksp,i+1,dp);
243:     (*ksp->converged)(ksp,i+1,dp,&ksp->reason,ksp->cnvP);
244:     if (ksp->reason) break;

246:     /* Apply PC if not already done for convergence check */
247:     if(ksp->normtype == KSP_NORM_UNPRECONDITIONED || ksp->normtype == KSP_NORM_NONE){
248:       KSP_PCApply(ksp,R,Z);               /*   z <- Br         */
249:     }

251:     /* Compute current C (which is W/dpi) */
252:     VecScale(Ccurr,1.0/dpi);              /*   w <- ci/dpi   */

254:     if (eigs) {
255:       if (i > 0) {
256:         if (ksp->max_it != stored_max_it) SETERRQ(PetscObjectComm((PetscObject)ksp),PETSC_ERR_SUP,"Can not change maxit AND calculate eigenvalues");
257:         e[i] = PetscSqrtReal(PetscAbsScalar(beta/betaold))/alphaold;
258:         d[i] = PetscSqrtReal(PetscAbsScalar(beta/betaold))*e[i] + 1.0/alpha;
259:       } else {
260:         d[i] = PetscSqrtReal(PetscAbsScalar(beta))*e[i] + 1.0/alpha;
261:       }
262:       fcg->ned = ksp->its-1;
263:     }
264:     ++i;
265:   } while (i<ksp->max_it);
266:   if (i >= ksp->max_it) ksp->reason = KSP_DIVERGED_ITS;
267:   return(0);
268: }

270: static PetscErrorCode KSPDestroy_FCG(KSP ksp)
271: {
273:   PetscInt       i;
274:   KSP_FCG        *fcg = (KSP_FCG*)ksp->data;


278:   /* Destroy "standard" work vecs */
279:   VecDestroyVecs(ksp->nwork,&ksp->work);

281:   /* Destroy P and C vectors and the arrays that manage pointers to them */
282:   if (fcg->nvecs){
283:     for (i=0;i<fcg->nchunks;++i){
284:       VecDestroyVecs(fcg->chunksizes[i],&fcg->pPvecs[i]);
285:       VecDestroyVecs(fcg->chunksizes[i],&fcg->pCvecs[i]);
286:     }
287:   }
288:   PetscFree5(fcg->Pvecs,fcg->Cvecs,fcg->pPvecs,fcg->pCvecs,fcg->chunksizes);
289:   /* free space used for singular value calculations */
290:   if (ksp->calc_sings) {
291:     PetscFree4(fcg->e,fcg->d,fcg->ee,fcg->dd);
292:   }
293:   KSPDestroyDefault(ksp);
294:   return(0);
295: }

297: static PetscErrorCode KSPView_FCG(KSP ksp,PetscViewer viewer)
298: {
299:   KSP_FCG        *fcg = (KSP_FCG*)ksp->data;
301:   PetscBool      iascii,isstring;
302:   const char     *truncstr;

305:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
306:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSTRING,&isstring);

308:   if (fcg->truncstrat == KSP_FCD_TRUNC_TYPE_STANDARD) truncstr = "Using standard truncation strategy";
309:   else if (fcg->truncstrat == KSP_FCD_TRUNC_TYPE_NOTAY) truncstr = "Using Notay's truncation strategy";
310:   else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Undefined FCG truncation strategy");

312:   if (iascii) {
313:     PetscViewerASCIIPrintf(viewer,"  m_max=%D\n",fcg->mmax);
314:     PetscViewerASCIIPrintf(viewer,"  preallocated %D directions\n",PetscMin(fcg->nprealloc,fcg->mmax+1));
315:     PetscViewerASCIIPrintf(viewer,"  %s\n",truncstr);
316:   } else if (isstring) {
317:     PetscViewerStringSPrintf(viewer,"m_max %D nprealloc %D %s",fcg->mmax,fcg->nprealloc,truncstr);
318:   }
319:   return(0);
320: }

322: /*@
323:   KSPFCGSetMmax - set the maximum number of previous directions FCG will store for orthogonalization

325:   Note: mmax + 1 directions are stored (mmax previous ones along with a current one)
326:   and whether all are used in each iteration also depends on the truncation strategy
327:   (see KSPFCGSetTruncationType())

329:   Logically Collective on ksp

331:   Input Parameters:
332: +  ksp - the Krylov space context
333: -  mmax - the maximum number of previous directions to orthogonalize againt

335:   Level: intermediate

337:   Options Database:
338: . -ksp_fcg_mmax <N>

340: .seealso: KSPFCG, KSPFCGGetTruncationType(), KSPFCGGetNprealloc()
341: @*/
342: PetscErrorCode KSPFCGSetMmax(KSP ksp,PetscInt mmax)
343: {
344:   KSP_FCG *fcg = (KSP_FCG*)ksp->data;

349:   fcg->mmax = mmax;
350:   return(0);
351: }

353: /*@
354:   KSPFCGGetMmax - get the maximum number of previous directions FCG will store

356:   Note: FCG stores mmax+1 directions at most (mmax previous ones, and one current one)

358:    Not Collective

360:    Input Parameter:
361: .  ksp - the Krylov space context

363:    Output Parameter:
364: .  mmax - the maximum number of previous directons allowed for orthogonalization

366:   Options Database:
367: . -ksp_fcg_mmax <N>

369:    Level: intermediate

371: .seealso: KSPFCG, KSPFCGGetTruncationType(), KSPFCGGetNprealloc(), KSPFCGSetMmax()
372: @*/

374: PetscErrorCode KSPFCGGetMmax(KSP ksp,PetscInt *mmax)
375: {
376:   KSP_FCG *fcg=(KSP_FCG*)ksp->data;

380:   *mmax = fcg->mmax;
381:   return(0);
382: }

384: /*@
385:   KSPFCGSetNprealloc - set the number of directions to preallocate with FCG

387:   Logically Collective on ksp

389:   Input Parameters:
390: +  ksp - the Krylov space context
391: -  nprealloc - the number of vectors to preallocate

393:   Level: advanced

395:   Options Database:
396: . -ksp_fcg_nprealloc <N> - number of directions to preallocate

398: .seealso: KSPFCG, KSPFCGGetTruncationType(), KSPFCGGetNprealloc()
399: @*/
400: PetscErrorCode KSPFCGSetNprealloc(KSP ksp,PetscInt nprealloc)
401: {
402:   KSP_FCG *fcg=(KSP_FCG*)ksp->data;

407:   if(nprealloc > fcg->mmax+1) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Cannot preallocate more than m_max+1 vectors");
408:   fcg->nprealloc = nprealloc;
409:   return(0);
410: }

412: /*@
413:   KSPFCGGetNprealloc - get the number of directions preallocate by FCG

415:    Not Collective

417:    Input Parameter:
418: .  ksp - the Krylov space context

420:    Output Parameter:
421: .  nprealloc - the number of directions preallocated

423:    Level: advanced

425: .seealso: KSPFCG, KSPFCGGetTruncationType(), KSPFCGSetNprealloc()
426: @*/
427: PetscErrorCode KSPFCGGetNprealloc(KSP ksp,PetscInt *nprealloc)
428: {
429:   KSP_FCG *fcg=(KSP_FCG*)ksp->data;

433:   *nprealloc = fcg->nprealloc;
434:   return(0);
435: }

437: /*@
438:   KSPFCGSetTruncationType - specify how many of its stored previous directions FCG uses during orthoganalization

440:   Logically Collective on ksp

442:   KSP_FCD_TRUNC_TYPE_STANDARD uses all (up to mmax) stored directions
443:   KSP_FCD_TRUNC_TYPE_NOTAY uses the last max(1,mod(i,mmax)) stored directions at iteration i=0,1,..

445:   Input Parameters:
446: +  ksp - the Krylov space context
447: -  truncstrat - the choice of strategy

449:   Level: intermediate

451:   Options Database:
452: . -ksp_fcg_truncation_type <standard, notay> - specify how many of its stored previous directions FCG uses during orthoganalization

454:   .seealso: KSPFCDTruncationType, KSPFCGGetTruncationType
455: @*/
456: PetscErrorCode KSPFCGSetTruncationType(KSP ksp,KSPFCDTruncationType truncstrat)
457: {
458:   KSP_FCG *fcg=(KSP_FCG*)ksp->data;

463:   fcg->truncstrat=truncstrat;
464:   return(0);
465: }

467: /*@
468:   KSPFCGGetTruncationType - get the truncation strategy employed by FCG

470:    Not Collective

472:    Input Parameter:
473: .  ksp - the Krylov space context

475:    Output Parameter:
476: .  truncstrat - the strategy type

478:    Level: intermediate

480: .seealso: KSPFCG, KSPFCGSetTruncationType, KSPFCDTruncationType
481: @*/
482: PetscErrorCode KSPFCGGetTruncationType(KSP ksp,KSPFCDTruncationType *truncstrat)
483: {
484:   KSP_FCG *fcg=(KSP_FCG*)ksp->data;

488:   *truncstrat=fcg->truncstrat;
489:   return(0);
490: }

492: static PetscErrorCode KSPSetFromOptions_FCG(PetscOptionItems *PetscOptionsObject,KSP ksp)
493: {
495:   KSP_FCG        *fcg=(KSP_FCG*)ksp->data;
496:   PetscInt       mmax,nprealloc;
497:   PetscBool      flg;

500:   PetscOptionsHead(PetscOptionsObject,"KSP FCG Options");
501:   PetscOptionsInt("-ksp_fcg_mmax","Maximum number of search directions to store","KSPFCGSetMmax",fcg->mmax,&mmax,&flg);
502:   if (flg) {
503:     KSPFCGSetMmax(ksp,mmax);
504:   }
505:   PetscOptionsInt("-ksp_fcg_nprealloc","Number of directions to preallocate","KSPFCGSetNprealloc",fcg->nprealloc,&nprealloc,&flg);
506:   if (flg) {
507:     KSPFCGSetNprealloc(ksp,nprealloc);
508:   }
509:   PetscOptionsEnum("-ksp_fcg_truncation_type","Truncation approach for directions","KSPFCGSetTruncationType",KSPFCDTruncationTypes,(PetscEnum)fcg->truncstrat,(PetscEnum*)&fcg->truncstrat,NULL);
510:   PetscOptionsTail();
511:   return(0);
512: }

514: /*MC
515:       KSPFCG - Implements the Flexible Conjugate Gradient method (FCG)

517:   Options Database Keys:
518: +   -ksp_fcg_mmax <N>  - maximum number of search directions
519: .   -ksp_fcg_nprealloc <N> - number of directions to preallocate
520: -   -ksp_fcg_truncation_type <standard,notay> - truncation approach for directions

522:     Contributed by Patrick Sanan

524:    Notes:
525:    Supports left preconditioning only.

527:    Level: beginner

529:   References:
530: +    1. - Notay, Y."Flexible Conjugate Gradients", SIAM J. Sci. Comput. 22:4, 2000
531: -    2. - Axelsson, O. and Vassilevski, P. S. "A Black Box Generalized Conjugate Gradient Solver with Inner Iterations and Variable step Preconditioning",
532:     SIAM J. Matrix Anal. Appl. 12:4, 1991

534:  .seealso : KSPGCR, KSPFGMRES, KSPCG, KSPFCGSetMmax(), KSPFCGGetMmax(), KSPFCGSetNprealloc(), KSPFCGGetNprealloc(), KSPFCGSetTruncationType(), KSPFCGGetTruncationType()

536: M*/
537: PETSC_EXTERN PetscErrorCode KSPCreate_FCG(KSP ksp)
538: {
540:   KSP_FCG        *fcg;

543:   PetscNewLog(ksp,&fcg);
544: #if !defined(PETSC_USE_COMPLEX)
545:   fcg->type       = KSP_CG_SYMMETRIC;
546: #else
547:   fcg->type       = KSP_CG_HERMITIAN;
548: #endif
549:   fcg->mmax       = KSPFCG_DEFAULT_MMAX;
550:   fcg->nprealloc  = KSPFCG_DEFAULT_NPREALLOC;
551:   fcg->nvecs      = 0;
552:   fcg->vecb       = KSPFCG_DEFAULT_VECB;
553:   fcg->nchunks    = 0;
554:   fcg->truncstrat = KSPFCG_DEFAULT_TRUNCSTRAT;

556:   ksp->data = (void*)fcg;

558:   KSPSetSupportedNorm(ksp,KSP_NORM_PRECONDITIONED,PC_LEFT,2);
559:   KSPSetSupportedNorm(ksp,KSP_NORM_UNPRECONDITIONED,PC_LEFT,1);
560:   KSPSetSupportedNorm(ksp,KSP_NORM_NATURAL,PC_LEFT,1);
561:   KSPSetSupportedNorm(ksp,KSP_NORM_NONE,PC_LEFT,1);

563:   ksp->ops->setup          = KSPSetUp_FCG;
564:   ksp->ops->solve          = KSPSolve_FCG;
565:   ksp->ops->destroy        = KSPDestroy_FCG;
566:   ksp->ops->view           = KSPView_FCG;
567:   ksp->ops->setfromoptions = KSPSetFromOptions_FCG;
568:   ksp->ops->buildsolution  = KSPBuildSolutionDefault;
569:   ksp->ops->buildresidual  = KSPBuildResidualDefault;
570:   return(0);
571: }