Date: 2024-10-28T09:13:10+00:00

Actual source code: lobpcg.c
slepc-3.22.1 2024-10-28
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */
     10: /*
     11:    SLEPc eigensolver: "lobpcg"

     13:    Method: Locally Optimal Block Preconditioned Conjugate Gradient

     15:    Algorithm:

     17:        LOBPCG with soft and hard locking. Follows the implementation
     18:        in BLOPEX [2].

     20:    References:

     22:        [1] A. V. Knyazev, "Toward the optimal preconditioned eigensolver:
     23:            locally optimal block preconditioned conjugate gradient method",
     24:            SIAM J. Sci. Comput. 23(2):517-541, 2001.

     26:        [2] A. V. Knyazev et al., "Block Locally Optimal Preconditioned
     27:            Eigenvalue Xolvers (BLOPEX) in Hypre and PETSc", SIAM J. Sci.
     28:            Comput. 29(5):2224-2239, 2007.
     29: */

     31: #include <slepc/private/epsimpl.h>

     33: typedef struct {
     34:   PetscInt  bs;        /* block size */
     35:   PetscBool lock;      /* soft locking active/inactive */
     36:   PetscReal restart;   /* restart parameter */
     37:   PetscInt  guard;     /* number of guard vectors */
     38: } EPS_LOBPCG;

     40: static PetscErrorCode EPSSetDimensions_LOBPCG(EPS eps,PetscInt nev,PetscInt *ncv,PetscInt *mpd)
     41: {
     42:   EPS_LOBPCG *ctx = (EPS_LOBPCG*)eps->data;
     43:   PetscInt   k;

     45:   PetscFunctionBegin;
     46:   k = PetscMax(3*ctx->bs,((eps->nev-1)/ctx->bs+3)*ctx->bs);
     47:   if (*ncv!=PETSC_DETERMINE) { /* ncv set */
     48:     PetscCheck(*ncv>=k,PetscObjectComm((PetscObject)eps),PETSC_ERR_USER_INPUT,"The value of ncv is not sufficiently large");
     49:   } else *ncv = k;
     50:   if (*mpd==PETSC_DETERMINE) *mpd = 3*ctx->bs;
     51:   else PetscCheck(*mpd==3*ctx->bs,PetscObjectComm((PetscObject)eps),PETSC_ERR_USER_INPUT,"This solver does not allow a value of mpd different from 3*blocksize");
     52:   PetscFunctionReturn(PETSC_SUCCESS);
     53: }

     55: static PetscErrorCode EPSSetUp_LOBPCG(EPS eps)
     56: {
     57:   EPS_LOBPCG     *ctx = (EPS_LOBPCG*)eps->data;

     59:   PetscFunctionBegin;
     60:   EPSCheckHermitianDefinite(eps);
     61:   EPSCheckNotStructured(eps);
     62:   if (!ctx->bs) ctx->bs = PetscMin(16,eps->nev);
     63:   PetscCheck(eps->n-eps->nds>=5*ctx->bs,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"The problem size is too small relative to the block size");
     64:   PetscCall(EPSSetDimensions_LOBPCG(eps,eps->nev,&eps->ncv,&eps->mpd));
     65:   if (eps->max_it==PETSC_DETERMINE) eps->max_it = PetscMax(100,2*eps->n/eps->ncv);
     66:   if (!eps->which) eps->which = EPS_SMALLEST_REAL;
     67:   PetscCheck(eps->which==EPS_SMALLEST_REAL || eps->which==EPS_LARGEST_REAL,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"This solver supports only smallest real or largest real eigenvalues");
     68:   EPSCheckUnsupported(eps,EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION | EPS_FEATURE_EXTRACTION);
     69:   EPSCheckIgnored(eps,EPS_FEATURE_BALANCE);

     71:   if (!ctx->restart) ctx->restart = 0.9;

     73:   /* number of guard vectors */
     74:   if (ctx->bs==1) ctx->guard = 0;
     75:   else ctx->guard = PetscMin((PetscInt)((1.0-ctx->restart)*ctx->bs+0.45),ctx->bs-1);

     77:   PetscCall(EPSAllocateSolution(eps,0));
     78:   PetscCall(EPS_SetInnerProduct(eps));
     79:   PetscCall(DSSetType(eps->ds,DSGHEP));
     80:   PetscCall(DSAllocate(eps->ds,eps->mpd));
     81:   PetscCall(EPSSetWorkVecs(eps,1));
     82:   PetscFunctionReturn(PETSC_SUCCESS);
     83: }

     85: static PetscErrorCode EPSSolve_LOBPCG(EPS eps)
     86: {
     87:   EPS_LOBPCG     *ctx = (EPS_LOBPCG*)eps->data;
     88:   PetscInt       i,j,k,nv,ini,nmat,nc,nconv,locked,its,prev=0;
     89:   PetscReal      norm;
     90:   PetscScalar    *eigr,dot;
     91:   PetscBool      breakdown,countc,flip=PETSC_FALSE,checkprecond=PETSC_FALSE;
     92:   Mat            A,B,M,V=NULL,W=NULL;
     93:   Vec            v,z,w=eps->work[0];
     94:   BV             X,Y=NULL,Z,R,P,AX,BX;
     95:   SlepcSC        sc;

     97:   PetscFunctionBegin;
     98:   PetscCall(STGetNumMatrices(eps->st,&nmat));
     99:   PetscCall(STGetMatrix(eps->st,0,&A));
    100:   if (nmat>1) PetscCall(STGetMatrix(eps->st,1,&B));
    101:   else B = NULL;

    103:   if (eps->which==EPS_LARGEST_REAL) {  /* flip spectrum */
    104:     flip = PETSC_TRUE;
    105:     PetscCall(DSGetSlepcSC(eps->ds,&sc));
    106:     sc->comparison = SlepcCompareSmallestReal;
    107:   }

    109:   /* undocumented option to check for a positive-definite preconditioner (turn-off by default) */
    110:   PetscCall(PetscOptionsGetBool(NULL,NULL,"-eps_lobpcg_checkprecond",&checkprecond,NULL));

    112:   /* 1. Allocate memory */
    113:   PetscCall(PetscCalloc1(3*ctx->bs,&eigr));
    114:   PetscCall(BVDuplicateResize(eps->V,3*ctx->bs,&Z));
    115:   PetscCall(BVDuplicateResize(eps->V,ctx->bs,&X));
    116:   PetscCall(BVDuplicateResize(eps->V,ctx->bs,&R));
    117:   PetscCall(BVDuplicateResize(eps->V,ctx->bs,&P));
    118:   PetscCall(BVDuplicateResize(eps->V,ctx->bs,&AX));
    119:   if (B) PetscCall(BVDuplicateResize(eps->V,ctx->bs,&BX));
    120:   nc = eps->nds;
    121:   if (nc>0 || eps->nev>ctx->bs-ctx->guard) PetscCall(BVDuplicateResize(eps->V,nc+eps->nev,&Y));
    122:   if (nc>0) {
    123:     for (j=0;j<nc;j++) {
    124:       PetscCall(BVGetColumn(eps->V,-nc+j,&v));
    125:       PetscCall(BVInsertVec(Y,j,v));
    126:       PetscCall(BVRestoreColumn(eps->V,-nc+j,&v));
    127:     }
    128:     PetscCall(BVSetActiveColumns(Y,0,nc));
    129:   }

    131:   /* 2. Apply the constraints to the initial vectors */
    132:   /* 3. B-orthogonalize initial vectors */
    133:   for (k=eps->nini;k<eps->ncv-ctx->bs;k++) { /* Generate more initial vectors if necessary */
    134:     PetscCall(BVSetRandomColumn(eps->V,k));
    135:     PetscCall(BVOrthonormalizeColumn(eps->V,k,PETSC_TRUE,NULL,NULL));
    136:   }
    137:   nv = ctx->bs;
    138:   PetscCall(BVSetActiveColumns(eps->V,0,nv));
    139:   PetscCall(BVSetActiveColumns(Z,0,nv));
    140:   PetscCall(BVCopy(eps->V,Z));
    141:   PetscCall(BVCopy(Z,X));

    143:   /* 4. Compute initial Ritz vectors */
    144:   PetscCall(BVMatMult(X,A,AX));
    145:   PetscCall(DSSetDimensions(eps->ds,nv,0,0));
    146:   PetscCall(DSGetMat(eps->ds,DS_MAT_A,&M));
    147:   PetscCall(BVMatProject(AX,NULL,X,M));
    148:   if (flip) PetscCall(MatScale(M,-1.0));
    149:   PetscCall(DSRestoreMat(eps->ds,DS_MAT_A,&M));
    150:   PetscCall(DSSetIdentity(eps->ds,DS_MAT_B));
    151:   PetscCall(DSSetState(eps->ds,DS_STATE_RAW));
    152:   PetscCall(DSSolve(eps->ds,eigr,NULL));
    153:   PetscCall(DSSort(eps->ds,eigr,NULL,NULL,NULL,NULL));
    154:   PetscCall(DSSynchronize(eps->ds,eigr,NULL));
    155:   for (j=0;j<nv;j++) eps->eigr[j] = flip? -eigr[j]: eigr[j];
    156:   PetscCall(DSVectors(eps->ds,DS_MAT_X,NULL,NULL));
    157:   PetscCall(DSGetMat(eps->ds,DS_MAT_X,&M));
    158:   PetscCall(BVMultInPlace(X,M,0,nv));
    159:   PetscCall(BVMultInPlace(AX,M,0,nv));
    160:   PetscCall(DSRestoreMat(eps->ds,DS_MAT_X,&M));

    162:   /* 5. Initialize range of active iterates */
    163:   locked = 0;  /* hard-locked vectors, the leading locked columns of V are eigenvectors */
    164:   nconv  = 0;  /* number of converged eigenvalues in the current block */
    165:   its    = 0;  /* iterations for the current block */

    167:   /* 6. Main loop */
    168:   while (eps->reason == EPS_CONVERGED_ITERATING) {

    170:     if (ctx->lock) {
    171:       PetscCall(BVSetActiveColumns(R,nconv,ctx->bs));
    172:       PetscCall(BVSetActiveColumns(AX,nconv,ctx->bs));
    173:       if (B) PetscCall(BVSetActiveColumns(BX,nconv,ctx->bs));
    174:     }

    176:     /* 7. Compute residuals */
    177:     ini = (ctx->lock)? nconv: 0;
    178:     PetscCall(BVCopy(AX,R));
    179:     if (B) PetscCall(BVMatMult(X,B,BX));
    180:     for (j=ini;j<ctx->bs;j++) {
    181:       PetscCall(BVGetColumn(R,j,&v));
    182:       PetscCall(BVGetColumn(B?BX:X,j,&z));
    183:       PetscCall(VecAXPY(v,-eps->eigr[locked+j],z));
    184:       PetscCall(BVRestoreColumn(R,j,&v));
    185:       PetscCall(BVRestoreColumn(B?BX:X,j,&z));
    186:     }

    188:     /* 8. Compute residual norms and update index set of active iterates */
    189:     k = ini;
    190:     countc = PETSC_TRUE;
    191:     for (j=ini;j<ctx->bs;j++) {
    192:       i = locked+j;
    193:       PetscCall(BVGetColumn(R,j,&v));
    194:       PetscCall(VecNorm(v,NORM_2,&norm));
    195:       PetscCall(BVRestoreColumn(R,j,&v));
    196:       PetscCall((*eps->converged)(eps,eps->eigr[i],eps->eigi[i],norm,&eps->errest[i],eps->convergedctx));
    197:       if (countc) {
    198:         if (eps->errest[i] < eps->tol) k++;
    199:         else countc = PETSC_FALSE;
    200:       }
    201:       if (!countc && !eps->trackall) break;
    202:     }
    203:     nconv = k;
    204:     eps->nconv = locked + nconv;
    205:     if (its) PetscCall(EPSMonitor(eps,eps->its+its,eps->nconv,eps->eigr,eps->eigi,eps->errest,locked+ctx->bs));
    206:     PetscCall((*eps->stopping)(eps,eps->its+its,eps->max_it,eps->nconv,eps->nev,&eps->reason,eps->stoppingctx));
    207:     if (eps->reason != EPS_CONVERGED_ITERATING || nconv >= ctx->bs-ctx->guard) {
    208:       PetscCall(BVSetActiveColumns(eps->V,locked,eps->nconv));
    209:       PetscCall(BVSetActiveColumns(X,0,nconv));
    210:       PetscCall(BVCopy(X,eps->V));
    211:     }
    212:     if (eps->reason != EPS_CONVERGED_ITERATING) {
    213:       break;
    214:     } else if (nconv >= ctx->bs-ctx->guard) {
    215:       eps->its += its-1;
    216:       its = 0;
    217:     } else its++;

    219:     if (nconv >= ctx->bs-ctx->guard) {  /* force hard locking of vectors and compute new R */

    221:       /* extend constraints */
    222:       PetscCall(BVSetActiveColumns(Y,nc+locked,nc+locked+nconv));
    223:       PetscCall(BVCopy(X,Y));
    224:       PetscCall(BVSetActiveColumns(Y,0,nc+locked+nconv));

    226:       /* shift work BV's */
    227:       for (j=nconv;j<ctx->bs;j++) {
    228:         PetscCall(BVCopyColumn(X,j,j-nconv));
    229:         PetscCall(BVCopyColumn(R,j,j-nconv));
    230:         PetscCall(BVCopyColumn(P,j,j-nconv));
    231:         PetscCall(BVCopyColumn(AX,j,j-nconv));
    232:         if (B) PetscCall(BVCopyColumn(BX,j,j-nconv));
    233:       }

    235:       /* set new initial vectors */
    236:       PetscCall(BVSetActiveColumns(eps->V,locked+ctx->bs,locked+ctx->bs+nconv));
    237:       PetscCall(BVSetActiveColumns(X,ctx->bs-nconv,ctx->bs));
    238:       PetscCall(BVCopy(eps->V,X));
    239:       for (j=ctx->bs-nconv;j<ctx->bs;j++) {
    240:         PetscCall(BVGetColumn(X,j,&v));
    241:         PetscCall(BVOrthogonalizeVec(Y,v,NULL,&norm,&breakdown));
    242:         if (norm>0.0 && !breakdown) PetscCall(VecScale(v,1.0/norm));
    243:         else {
    244:           PetscCall(PetscInfo(eps,"Orthogonalization of initial vector failed\n"));
    245:           eps->reason = EPS_DIVERGED_BREAKDOWN;
    246:           goto diverged;
    247:         }
    248:         PetscCall(BVRestoreColumn(X,j,&v));
    249:       }
    250:       locked += nconv;
    251:       nconv = 0;
    252:       PetscCall(BVSetActiveColumns(X,nconv,ctx->bs));

    254:       /* B-orthogonalize initial vectors */
    255:       PetscCall(BVOrthogonalize(X,NULL));
    256:       PetscCall(BVSetActiveColumns(Z,nconv,ctx->bs));
    257:       PetscCall(BVSetActiveColumns(AX,nconv,ctx->bs));
    258:       PetscCall(BVCopy(X,Z));

    260:       /* compute initial Ritz vectors */
    261:       nv = ctx->bs;
    262:       PetscCall(BVMatMult(X,A,AX));
    263:       PetscCall(DSSetDimensions(eps->ds,nv,0,0));
    264:       PetscCall(DSGetMat(eps->ds,DS_MAT_A,&M));
    265:       PetscCall(BVMatProject(AX,NULL,X,M));
    266:       if (flip) PetscCall(MatScale(M,-1.0));
    267:       PetscCall(DSRestoreMat(eps->ds,DS_MAT_A,&M));
    268:       PetscCall(DSSetIdentity(eps->ds,DS_MAT_B));
    269:       PetscCall(DSSetState(eps->ds,DS_STATE_RAW));
    270:       PetscCall(DSSolve(eps->ds,eigr,NULL));
    271:       PetscCall(DSSort(eps->ds,eigr,NULL,NULL,NULL,NULL));
    272:       PetscCall(DSSynchronize(eps->ds,eigr,NULL));
    273:       for (j=0;j<nv;j++) if (locked+j<eps->ncv) eps->eigr[locked+j] = flip? -eigr[j]: eigr[j];
    274:       PetscCall(DSVectors(eps->ds,DS_MAT_X,NULL,NULL));
    275:       PetscCall(DSGetMat(eps->ds,DS_MAT_X,&M));
    276:       PetscCall(BVMultInPlace(X,M,0,nv));
    277:       PetscCall(BVMultInPlace(AX,M,0,nv));
    278:       PetscCall(DSRestoreMat(eps->ds,DS_MAT_X,&M));

    280:       continue;   /* skip the rest of the iteration */
    281:     }

    283:     ini = (ctx->lock)? nconv: 0;
    284:     if (ctx->lock) {
    285:       PetscCall(BVSetActiveColumns(R,nconv,ctx->bs));
    286:       PetscCall(BVSetActiveColumns(P,nconv,ctx->bs));
    287:       PetscCall(BVSetActiveColumns(AX,nconv,ctx->bs));
    288:       if (B) PetscCall(BVSetActiveColumns(BX,nconv,ctx->bs));
    289:     }

    291:     /* 9. Apply preconditioner to the residuals */
    292:     PetscCall(BVGetMat(R,&V));
    293:     if (prev != ctx->bs-ini) {
    294:       prev = ctx->bs-ini;
    295:       PetscCall(MatDestroy(&W));
    296:       PetscCall(MatDuplicate(V,MAT_SHARE_NONZERO_PATTERN,&W));
    297:     }
    298:     PetscCall(STApplyMat(eps->st,V,W));
    299:     if (checkprecond) {
    300:       for (j=ini;j<ctx->bs;j++) {
    301:         PetscCall(MatDenseGetColumnVecRead(V,j-ini,&v));
    302:         PetscCall(MatDenseGetColumnVecRead(W,j-ini,&w));
    303:         PetscCall(VecDot(v,w,&dot));
    304:         PetscCall(MatDenseRestoreColumnVecRead(W,j-ini,&w));
    305:         PetscCall(MatDenseRestoreColumnVecRead(V,j-ini,&v));
    306:         if (PetscRealPart(dot)<0.0) {
    307:           PetscCall(PetscInfo(eps,"The preconditioner is not positive-definite\n"));
    308:           eps->reason = EPS_DIVERGED_BREAKDOWN;
    309:           goto diverged;
    310:         }
    311:       }
    312:     }
    313:     if (nc+locked>0) {
    314:       for (j=ini;j<ctx->bs;j++) {
    315:         PetscCall(MatDenseGetColumnVecWrite(W,j-ini,&w));
    316:         PetscCall(BVOrthogonalizeVec(Y,w,NULL,&norm,&breakdown));
    317:         if (norm>0.0 && !breakdown) PetscCall(VecScale(w,1.0/norm));
    318:         PetscCall(MatDenseRestoreColumnVecWrite(W,j-ini,&w));
    319:         if (norm<=0.0 || breakdown) {
    320:           PetscCall(PetscInfo(eps,"Orthogonalization of preconditioned residual failed\n"));
    321:           eps->reason = EPS_DIVERGED_BREAKDOWN;
    322:           goto diverged;
    323:         }
    324:       }
    325:     }
    326:     PetscCall(MatCopy(W,V,SAME_NONZERO_PATTERN));
    327:     PetscCall(BVRestoreMat(R,&V));

    329:     /* 11. B-orthonormalize preconditioned residuals */
    330:     PetscCall(BVOrthogonalize(R,NULL));

    332:     /* 13-16. B-orthonormalize conjugate directions */
    333:     if (its>1) PetscCall(BVOrthogonalize(P,NULL));

    335:     /* 17-23. Compute symmetric Gram matrices */
    336:     PetscCall(BVSetActiveColumns(Z,0,ctx->bs));
    337:     PetscCall(BVSetActiveColumns(X,0,ctx->bs));
    338:     PetscCall(BVCopy(X,Z));
    339:     PetscCall(BVSetActiveColumns(Z,ctx->bs,2*ctx->bs-ini));
    340:     PetscCall(BVCopy(R,Z));
    341:     if (its>1) {
    342:       PetscCall(BVSetActiveColumns(Z,2*ctx->bs-ini,3*ctx->bs-2*ini));
    343:       PetscCall(BVCopy(P,Z));
    344:     }

    346:     if (its>1) nv = 3*ctx->bs-2*ini;
    347:     else nv = 2*ctx->bs-ini;

    349:     PetscCall(BVSetActiveColumns(Z,0,nv));
    350:     PetscCall(DSSetDimensions(eps->ds,nv,0,0));
    351:     PetscCall(DSGetMat(eps->ds,DS_MAT_A,&M));
    352:     PetscCall(BVMatProject(Z,A,Z,M));
    353:     if (flip) PetscCall(MatScale(M,-1.0));
    354:     PetscCall(DSRestoreMat(eps->ds,DS_MAT_A,&M));
    355:     PetscCall(DSGetMat(eps->ds,DS_MAT_B,&M));
    356:     PetscCall(BVMatProject(Z,B,Z,M)); /* covers also the case B=NULL */
    357:     PetscCall(DSRestoreMat(eps->ds,DS_MAT_B,&M));

    359:     /* 24. Solve the generalized eigenvalue problem */
    360:     PetscCall(DSSetState(eps->ds,DS_STATE_RAW));
    361:     PetscCall(DSSolve(eps->ds,eigr,NULL));
    362:     PetscCall(DSSort(eps->ds,eigr,NULL,NULL,NULL,NULL));
    363:     PetscCall(DSSynchronize(eps->ds,eigr,NULL));
    364:     for (j=0;j<nv;j++) if (locked+j<eps->ncv) eps->eigr[locked+j] = flip? -eigr[j]: eigr[j];
    365:     PetscCall(DSVectors(eps->ds,DS_MAT_X,NULL,NULL));

    367:     /* 25-33. Compute Ritz vectors */
    368:     PetscCall(DSGetMat(eps->ds,DS_MAT_X,&M));
    369:     PetscCall(BVSetActiveColumns(Z,ctx->bs,nv));
    370:     if (ctx->lock) PetscCall(BVSetActiveColumns(P,0,ctx->bs));
    371:     PetscCall(BVMult(P,1.0,0.0,Z,M));
    372:     PetscCall(BVCopy(P,X));
    373:     if (ctx->lock) PetscCall(BVSetActiveColumns(P,nconv,ctx->bs));
    374:     PetscCall(BVSetActiveColumns(Z,0,ctx->bs));
    375:     PetscCall(BVMult(X,1.0,1.0,Z,M));
    376:     if (ctx->lock) PetscCall(BVSetActiveColumns(X,nconv,ctx->bs));
    377:     PetscCall(BVMatMult(X,A,AX));
    378:     PetscCall(DSRestoreMat(eps->ds,DS_MAT_X,&M));
    379:   }

    381: diverged:
    382:   eps->its += its;

    384:   if (flip) sc->comparison = SlepcCompareLargestReal;
    385:   PetscCall(PetscFree(eigr));
    386:   PetscCall(MatDestroy(&W));
    387:   if (V) PetscCall(BVRestoreMat(R,&V)); /* only needed when goto diverged is reached */
    388:   PetscCall(BVDestroy(&Z));
    389:   PetscCall(BVDestroy(&X));
    390:   PetscCall(BVDestroy(&R));
    391:   PetscCall(BVDestroy(&P));
    392:   PetscCall(BVDestroy(&AX));
    393:   if (B) PetscCall(BVDestroy(&BX));
    394:   if (nc>0 || eps->nev>ctx->bs-ctx->guard) PetscCall(BVDestroy(&Y));
    395:   PetscFunctionReturn(PETSC_SUCCESS);
    396: }

    398: static PetscErrorCode EPSLOBPCGSetBlockSize_LOBPCG(EPS eps,PetscInt bs)
    399: {
    400:   EPS_LOBPCG *ctx = (EPS_LOBPCG*)eps->data;

    402:   PetscFunctionBegin;
    403:   if (bs == PETSC_DEFAULT || bs == PETSC_DECIDE) bs = 0;
    404:   else PetscCheck(bs>0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"Invalid block size %" PetscInt_FMT,bs);
    405:   if (ctx->bs != bs) {
    406:     ctx->bs = bs;
    407:     eps->state = EPS_STATE_INITIAL;
    408:   }
    409:   PetscFunctionReturn(PETSC_SUCCESS);
    410: }

    412: /*@
    413:    EPSLOBPCGSetBlockSize - Sets the block size of the LOBPCG method.

    415:    Logically Collective

    417:    Input Parameters:
    418: +  eps - the eigenproblem solver context
    419: -  bs  - the block size

    421:    Options Database Key:
    422: .  -eps_lobpcg_blocksize - Sets the block size

    424:    Level: advanced

    426: .seealso: EPSLOBPCGGetBlockSize()
    427: @*/
    428: PetscErrorCode EPSLOBPCGSetBlockSize(EPS eps,PetscInt bs)
    429: {
    430:   PetscFunctionBegin;
    433:   PetscTryMethod(eps,"EPSLOBPCGSetBlockSize_C",(EPS,PetscInt),(eps,bs));
    434:   PetscFunctionReturn(PETSC_SUCCESS);
    435: }

    437: static PetscErrorCode EPSLOBPCGGetBlockSize_LOBPCG(EPS eps,PetscInt *bs)
    438: {
    439:   EPS_LOBPCG *ctx = (EPS_LOBPCG*)eps->data;

    441:   PetscFunctionBegin;
    442:   *bs = ctx->bs;
    443:   PetscFunctionReturn(PETSC_SUCCESS);
    444: }

    446: /*@
    447:    EPSLOBPCGGetBlockSize - Gets the block size used in the LOBPCG method.

    449:    Not Collective

    451:    Input Parameter:
    452: .  eps - the eigenproblem solver context

    454:    Output Parameter:
    455: .  bs - the block size

    457:    Level: advanced

    459: .seealso: EPSLOBPCGSetBlockSize()
    460: @*/
    461: PetscErrorCode EPSLOBPCGGetBlockSize(EPS eps,PetscInt *bs)
    462: {
    463:   PetscFunctionBegin;
    465:   PetscAssertPointer(bs,2);
    466:   PetscUseMethod(eps,"EPSLOBPCGGetBlockSize_C",(EPS,PetscInt*),(eps,bs));
    467:   PetscFunctionReturn(PETSC_SUCCESS);
    468: }

    470: static PetscErrorCode EPSLOBPCGSetRestart_LOBPCG(EPS eps,PetscReal restart)
    471: {
    472:   EPS_LOBPCG *ctx = (EPS_LOBPCG*)eps->data;

    474:   PetscFunctionBegin;
    475:   if (restart==(PetscReal)PETSC_DEFAULT || restart==(PetscReal)PETSC_DECIDE) restart = 0.9;
    476:   PetscCheck(restart>=0.1 && restart<=1.0,PetscObjectComm((PetscObject)eps),PETSC_ERR_ARG_OUTOFRANGE,"The restart argument %g must be in the range [0.1,1.0]",(double)restart);
    477:   if (restart != ctx->restart) {
    478:     ctx->restart = restart;
    479:     eps->state = EPS_STATE_INITIAL;
    480:   }
    481:   PetscFunctionReturn(PETSC_SUCCESS);
    482: }

    484: /*@
    485:    EPSLOBPCGSetRestart - Sets the restart parameter for the LOBPCG method.

    487:    Logically Collective

    489:    Input Parameters:
    490: +  eps - the eigenproblem solver context
    491: -  restart - the percentage of the block of vectors to force a restart

    493:    Options Database Key:
    494: .  -eps_lobpcg_restart - Sets the restart parameter

    496:    Notes:
    497:    The meaning of this parameter is the proportion of vectors within the
    498:    current block iterate that must have converged in order to force a
    499:    restart with hard locking.
    500:    Allowed values are in the range [0.1,1.0]. The default is 0.9.

    502:    Level: advanced

    504: .seealso: EPSLOBPCGGetRestart()
    505: @*/
    506: PetscErrorCode EPSLOBPCGSetRestart(EPS eps,PetscReal restart)
    507: {
    508:   PetscFunctionBegin;
    511:   PetscTryMethod(eps,"EPSLOBPCGSetRestart_C",(EPS,PetscReal),(eps,restart));
    512:   PetscFunctionReturn(PETSC_SUCCESS);
    513: }

    515: static PetscErrorCode EPSLOBPCGGetRestart_LOBPCG(EPS eps,PetscReal *restart)
    516: {
    517:   EPS_LOBPCG *ctx = (EPS_LOBPCG*)eps->data;

    519:   PetscFunctionBegin;
    520:   *restart = ctx->restart;
    521:   PetscFunctionReturn(PETSC_SUCCESS);
    522: }

    524: /*@
    525:    EPSLOBPCGGetRestart - Gets the restart parameter used in the LOBPCG method.

    527:    Not Collective

    529:    Input Parameter:
    530: .  eps - the eigenproblem solver context

    532:    Output Parameter:
    533: .  restart - the restart parameter

    535:    Level: advanced

    537: .seealso: EPSLOBPCGSetRestart()
    538: @*/
    539: PetscErrorCode EPSLOBPCGGetRestart(EPS eps,PetscReal *restart)
    540: {
    541:   PetscFunctionBegin;
    543:   PetscAssertPointer(restart,2);
    544:   PetscUseMethod(eps,"EPSLOBPCGGetRestart_C",(EPS,PetscReal*),(eps,restart));
    545:   PetscFunctionReturn(PETSC_SUCCESS);
    546: }

    548: static PetscErrorCode EPSLOBPCGSetLocking_LOBPCG(EPS eps,PetscBool lock)
    549: {
    550:   EPS_LOBPCG *ctx = (EPS_LOBPCG*)eps->data;

    552:   PetscFunctionBegin;
    553:   ctx->lock = lock;
    554:   PetscFunctionReturn(PETSC_SUCCESS);
    555: }

    557: /*@
    558:    EPSLOBPCGSetLocking - Choose between locking and non-locking variants of
    559:    the LOBPCG method.

    561:    Logically Collective

    563:    Input Parameters:
    564: +  eps  - the eigenproblem solver context
    565: -  lock - true if the locking variant must be selected

    567:    Options Database Key:
    568: .  -eps_lobpcg_locking - Sets the locking flag

    570:    Notes:
    571:    This flag refers to soft locking (converged vectors within the current
    572:    block iterate), since hard locking is always used (when nev is larger
    573:    than the block size).

    575:    Level: advanced

    577: .seealso: EPSLOBPCGGetLocking()
    578: @*/
    579: PetscErrorCode EPSLOBPCGSetLocking(EPS eps,PetscBool lock)
    580: {
    581:   PetscFunctionBegin;
    584:   PetscTryMethod(eps,"EPSLOBPCGSetLocking_C",(EPS,PetscBool),(eps,lock));
    585:   PetscFunctionReturn(PETSC_SUCCESS);
    586: }

    588: static PetscErrorCode EPSLOBPCGGetLocking_LOBPCG(EPS eps,PetscBool *lock)
    589: {
    590:   EPS_LOBPCG *ctx = (EPS_LOBPCG*)eps->data;

    592:   PetscFunctionBegin;
    593:   *lock = ctx->lock;
    594:   PetscFunctionReturn(PETSC_SUCCESS);
    595: }

    597: /*@
    598:    EPSLOBPCGGetLocking - Gets the locking flag used in the LOBPCG method.

    600:    Not Collective

    602:    Input Parameter:
    603: .  eps - the eigenproblem solver context

    605:    Output Parameter:
    606: .  lock - the locking flag

    608:    Level: advanced

    610: .seealso: EPSLOBPCGSetLocking()
    611: @*/
    612: PetscErrorCode EPSLOBPCGGetLocking(EPS eps,PetscBool *lock)
    613: {
    614:   PetscFunctionBegin;
    616:   PetscAssertPointer(lock,2);
    617:   PetscUseMethod(eps,"EPSLOBPCGGetLocking_C",(EPS,PetscBool*),(eps,lock));
    618:   PetscFunctionReturn(PETSC_SUCCESS);
    619: }

    621: static PetscErrorCode EPSView_LOBPCG(EPS eps,PetscViewer viewer)
    622: {
    623:   EPS_LOBPCG     *ctx = (EPS_LOBPCG*)eps->data;
    624:   PetscBool      isascii;

    626:   PetscFunctionBegin;
    627:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii));
    628:   if (isascii) {
    629:     PetscCall(PetscViewerASCIIPrintf(viewer,"  block size %" PetscInt_FMT "\n",ctx->bs));
    630:     PetscCall(PetscViewerASCIIPrintf(viewer,"  restart parameter=%g (using %" PetscInt_FMT " guard vectors)\n",(double)ctx->restart,ctx->guard));
    631:     PetscCall(PetscViewerASCIIPrintf(viewer,"  soft locking %sactivated\n",ctx->lock?"":"de"));
    632:   }
    633:   PetscFunctionReturn(PETSC_SUCCESS);
    634: }

    636: static PetscErrorCode EPSSetFromOptions_LOBPCG(EPS eps,PetscOptionItems *PetscOptionsObject)
    637: {
    638:   PetscBool      lock,flg;
    639:   PetscInt       bs;
    640:   PetscReal      restart;

    642:   PetscFunctionBegin;
    643:   PetscOptionsHeadBegin(PetscOptionsObject,"EPS LOBPCG Options");

    645:     PetscCall(PetscOptionsInt("-eps_lobpcg_blocksize","Block size","EPSLOBPCGSetBlockSize",20,&bs,&flg));
    646:     if (flg) PetscCall(EPSLOBPCGSetBlockSize(eps,bs));

    648:     PetscCall(PetscOptionsReal("-eps_lobpcg_restart","Percentage of the block of vectors to force a restart","EPSLOBPCGSetRestart",0.5,&restart,&flg));
    649:     if (flg) PetscCall(EPSLOBPCGSetRestart(eps,restart));

    651:     PetscCall(PetscOptionsBool("-eps_lobpcg_locking","Choose between locking and non-locking variants","EPSLOBPCGSetLocking",PETSC_TRUE,&lock,&flg));
    652:     if (flg) PetscCall(EPSLOBPCGSetLocking(eps,lock));

    654:   PetscOptionsHeadEnd();
    655:   PetscFunctionReturn(PETSC_SUCCESS);
    656: }

    658: static PetscErrorCode EPSDestroy_LOBPCG(EPS eps)
    659: {
    660:   PetscFunctionBegin;
    661:   PetscCall(PetscFree(eps->data));
    662:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGSetBlockSize_C",NULL));
    663:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGGetBlockSize_C",NULL));
    664:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGSetRestart_C",NULL));
    665:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGGetRestart_C",NULL));
    666:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGSetLocking_C",NULL));
    667:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGGetLocking_C",NULL));
    668:   PetscFunctionReturn(PETSC_SUCCESS);
    669: }

    671: SLEPC_EXTERN PetscErrorCode EPSCreate_LOBPCG(EPS eps)
    672: {
    673:   EPS_LOBPCG     *lobpcg;

    675:   PetscFunctionBegin;
    676:   PetscCall(PetscNew(&lobpcg));
    677:   eps->data = (void*)lobpcg;
    678:   lobpcg->lock = PETSC_TRUE;

    680:   eps->useds = PETSC_TRUE;
    681:   eps->categ = EPS_CATEGORY_PRECOND;

    683:   eps->ops->solve          = EPSSolve_LOBPCG;
    684:   eps->ops->setup          = EPSSetUp_LOBPCG;
    685:   eps->ops->setupsort      = EPSSetUpSort_Default;
    686:   eps->ops->setfromoptions = EPSSetFromOptions_LOBPCG;
    687:   eps->ops->destroy        = EPSDestroy_LOBPCG;
    688:   eps->ops->view           = EPSView_LOBPCG;
    689:   eps->ops->backtransform  = EPSBackTransform_Default;
    690:   eps->ops->setdefaultst   = EPSSetDefaultST_GMRES;

    692:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGSetBlockSize_C",EPSLOBPCGSetBlockSize_LOBPCG));
    693:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGGetBlockSize_C",EPSLOBPCGGetBlockSize_LOBPCG));
    694:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGSetRestart_C",EPSLOBPCGSetRestart_LOBPCG));
    695:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGGetRestart_C",EPSLOBPCGGetRestart_LOBPCG));
    696:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGSetLocking_C",EPSLOBPCGSetLocking_LOBPCG));
    697:   PetscCall(PetscObjectComposeFunction((PetscObject)eps,"EPSLOBPCGGetLocking_C",EPSLOBPCGGetLocking_LOBPCG));
    698:   PetscFunctionReturn(PETSC_SUCCESS);
    699: }