Actual source code: svdprimme.c

      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:    This file implements a wrapper to the PRIMME SVD solver
     12: */

     14: #include <slepc/private/svdimpl.h>

     16: #include <primme.h>

     18: #if defined(PETSC_USE_COMPLEX)
     19: #if defined(PETSC_USE_REAL_SINGLE)
     20: #define PRIMME_DRIVER cprimme_svds
     21: #else
     22: #define PRIMME_DRIVER zprimme_svds
     23: #endif
     24: #else
     25: #if defined(PETSC_USE_REAL_SINGLE)
     26: #define PRIMME_DRIVER sprimme_svds
     27: #else
     28: #define PRIMME_DRIVER dprimme_svds
     29: #endif
     30: #endif

     32: #if defined(PRIMME_VERSION_MAJOR) && PRIMME_VERSION_MAJOR*100+PRIMME_VERSION_MINOR >= 202
     33: #define SLEPC_HAVE_PRIMME2p2
     34: #endif

     36: typedef struct {
     37:   primme_svds_params        primme;   /* param struct */
     38:   PetscInt                  bs;       /* block size */
     39:   primme_svds_preset_method method;   /* primme method */
     40:   SVD                       svd;      /* reference to the solver */
     41:   Vec                       x,y;      /* auxiliary vectors */
     42: } SVD_PRIMME;

     44: static void multMatvec_PRIMME(void*,PRIMME_INT*,void*,PRIMME_INT*,int*,int*,struct primme_svds_params*,int*);

     46: static void par_GlobalSumReal(void *sendBuf,void *recvBuf,int *count,primme_svds_params *primme,int *ierr)
     47: {
     48:   if (sendBuf == recvBuf) {
     49:     *ierr = MPI_Allreduce(MPI_IN_PLACE,recvBuf,*count,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)primme->commInfo));
     50:   } else {
     51:     *ierr = MPI_Allreduce(sendBuf,recvBuf,*count,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)primme->commInfo));
     52:   }
     53: }

     55: #if defined(SLEPC_HAVE_PRIMME3)
     56: static void par_broadcastReal(void *buf,int *count,primme_svds_params *primme,int *ierr)
     57: {
     58:   *ierr = MPI_Bcast(buf,*count,MPIU_REAL,0/*root*/,PetscObjectComm((PetscObject)primme->commInfo));
     59: }
     60: #endif

     62: #if defined(SLEPC_HAVE_PRIMME2p2)
     63: static void convTestFun(double *sval,void *leftsvec,void *rightsvec,double *resNorm,
     64: #if defined(SLEPC_HAVE_PRIMME3)
     65:                         int *method,
     66: #endif
     67:                         int *isconv,struct primme_svds_params *primme,int *err)
     68: {
     69:   PetscErrorCode ierr;
     70:   SVD            svd = (SVD)primme->commInfo;
     71:   PetscReal      sigma = sval?*sval:0.0;
     72:   PetscReal      r = resNorm?*resNorm:HUGE_VAL,errest;

     74:   ierr = (*svd->converged)(svd,sigma,r,&errest,svd->convergedctx);
     75:   if (ierr) *err = 1;
     76:   else {
     77:     *isconv = (errest<=svd->tol?1:0);
     78:     *err = 0;
     79:   }
     80: }

     82: static void monitorFun(void *basisSvals,int *basisSize,int *basisFlags,int *iblock,int *blockSize,void *basisNorms,int *numConverged,void *lockedSvals,int *numLocked,int *lockedFlags,void *lockedNorms,int *inner_its,void *LSRes,
     83: #if defined(SLEPC_HAVE_PRIMME3)
     84:                        const char *msg,double *time,
     85: #endif
     86:                        primme_event *event,int *stage,struct primme_svds_params *primme,int *err)
     87: {

     89:   PetscErrorCode ierr = PETSC_SUCCESS;
     90:   SVD            svd = (SVD)primme->commInfo;
     91:   PetscInt       i,k,nerrest;

     93:   *err = 1;
     94:   switch (*event) {
     95:     case primme_event_outer_iteration:
     96:       /* Update SVD */
     97:       PetscCallVoid(PetscIntCast(primme->stats.numOuterIterations,&svd->its));
     98:       if (numConverged) svd->nconv = *numConverged;
     99:       k = 0;
    100:       if (lockedSvals && numLocked) for (i=0; i<*numLocked && k<svd->ncv; i++) svd->sigma[k++] = ((PetscReal*)lockedSvals)[i];
    101:       nerrest = k;
    102:       if (iblock && blockSize) {
    103:         for (i=0; i<*blockSize && k+iblock[i]<svd->ncv; i++) svd->errest[k+iblock[i]] = ((PetscReal*)basisNorms)[i];
    104:         nerrest = k+(*blockSize>0?1+iblock[*blockSize-1]:0);
    105:       }
    106:       if (basisSvals && basisSize) for (i=0; i<*basisSize && k<svd->ncv; i++) svd->sigma[k++] = ((PetscReal*)basisSvals)[i];
    107:       /* Show progress */
    108:       ierr = SVDMonitor(svd,svd->its,numConverged?*numConverged:0,svd->sigma,svd->errest,nerrest);
    109:       break;
    110: #if defined(SLEPC_HAVE_PRIMME3)
    111:     case primme_event_message:
    112:       /* Print PRIMME information messages */
    113:       ierr = PetscInfo(svd,"%s\n",msg);
    114:       break;
    115: #endif
    116:     default:
    117:       break;
    118:   }
    119:   *err = (ierr!=0)? 1: 0;
    120: }
    121: #endif /* SLEPC_HAVE_PRIMME2p2 */

    123: static void multMatvec_PRIMME(void *xa,PRIMME_INT *ldx,void *ya,PRIMME_INT *ldy,int *blockSize,int *transpose,struct primme_svds_params *primme,int *ierr)
    124: {
    125:   PetscInt   i;
    126:   SVD_PRIMME *ops = (SVD_PRIMME*)primme->matrix;
    127:   Vec        x = ops->x,y = ops->y;
    128:   SVD        svd = ops->svd;

    130:   PetscFunctionBegin;
    131:   for (i=0;i<*blockSize;i++) {
    132:     if (*transpose) {
    133:       PetscCallAbort(PetscObjectComm((PetscObject)svd),VecPlaceArray(y,(PetscScalar*)xa+(*ldx)*i));
    134:       PetscCallAbort(PetscObjectComm((PetscObject)svd),VecPlaceArray(x,(PetscScalar*)ya+(*ldy)*i));
    135:       PetscCallAbort(PetscObjectComm((PetscObject)svd),MatMult(svd->AT,y,x));
    136:     } else {
    137:       PetscCallAbort(PetscObjectComm((PetscObject)svd),VecPlaceArray(x,(PetscScalar*)xa+(*ldx)*i));
    138:       PetscCallAbort(PetscObjectComm((PetscObject)svd),VecPlaceArray(y,(PetscScalar*)ya+(*ldy)*i));
    139:       PetscCallAbort(PetscObjectComm((PetscObject)svd),MatMult(svd->A,x,y));
    140:     }
    141:     PetscCallAbort(PetscObjectComm((PetscObject)svd),VecResetArray(x));
    142:     PetscCallAbort(PetscObjectComm((PetscObject)svd),VecResetArray(y));
    143:   }
    144:   PetscFunctionReturnVoid();
    145: }

    147: static PetscErrorCode SVDSetUp_PRIMME(SVD svd)
    148: {
    149:   PetscMPIInt        numProcs,procID;
    150:   PetscInt           n,m,nloc,mloc;
    151:   SVD_PRIMME         *ops = (SVD_PRIMME*)svd->data;
    152:   primme_svds_params *primme = &ops->primme;

    154:   PetscFunctionBegin;
    155:   SVDCheckStandard(svd);
    156:   SVDCheckDefinite(svd);
    157:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)svd),&numProcs));
    158:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)svd),&procID));

    160:   /* Check some constraints and set some default values */
    161:   PetscCall(MatGetSize(svd->A,&m,&n));
    162:   PetscCall(MatGetLocalSize(svd->A,&mloc,&nloc));
    163:   PetscCall(SVDSetDimensions_Default(svd));
    164:   if (svd->max_it==PETSC_DETERMINE) svd->max_it = PETSC_INT_MAX;
    165:   svd->leftbasis = PETSC_TRUE;
    166:   SVDCheckUnsupported(svd,SVD_FEATURE_STOPPING);
    167: #if !defined(SLEPC_HAVE_PRIMME2p2)
    168:   if (svd->converged != SVDConvergedAbsolute) PetscCall(PetscInfo(svd,"Warning: using absolute convergence test\n"));
    169: #endif

    171:   /* Transfer SLEPc options to PRIMME options */
    172:   primme_svds_free(primme);
    173:   primme_svds_initialize(primme);
    174:   primme->m             = (PRIMME_INT)m;
    175:   primme->n             = (PRIMME_INT)n;
    176:   primme->mLocal        = (PRIMME_INT)mloc;
    177:   primme->nLocal        = (PRIMME_INT)nloc;
    178:   primme->numSvals      = (int)svd->nsv;
    179:   primme->matrix        = ops;
    180:   primme->commInfo      = svd;
    181:   primme->maxMatvecs    = (PRIMME_INT)svd->max_it;
    182: #if !defined(SLEPC_HAVE_PRIMME2p2)
    183:   primme->eps           = SlepcDefaultTol(svd->tol);
    184: #endif
    185:   primme->numProcs      = numProcs;
    186:   primme->procID        = procID;
    187:   primme->printLevel    = 1;
    188:   primme->matrixMatvec  = multMatvec_PRIMME;
    189:   primme->globalSumReal = par_GlobalSumReal;
    190: #if defined(SLEPC_HAVE_PRIMME3)
    191:   primme->broadcastReal = par_broadcastReal;
    192: #endif
    193: #if defined(SLEPC_HAVE_PRIMME2p2)
    194:   primme->convTestFun   = convTestFun;
    195:   primme->monitorFun    = monitorFun;
    196: #endif
    197:   if (ops->bs > 0) primme->maxBlockSize = (int)ops->bs;

    199:   switch (svd->which) {
    200:     case SVD_LARGEST:
    201:       primme->target = primme_svds_largest;
    202:       break;
    203:     case SVD_SMALLEST:
    204:       primme->target = primme_svds_smallest;
    205:       break;
    206:   }

    208:   /* If user sets mpd or ncv, maxBasisSize is modified */
    209:   if (svd->mpd!=PETSC_DETERMINE) {
    210:     primme->maxBasisSize = (int)svd->mpd;
    211:     if (svd->ncv!=PETSC_DETERMINE) PetscCall(PetscInfo(svd,"Warning: 'ncv' is ignored by PRIMME\n"));
    212:   } else if (svd->ncv!=PETSC_DETERMINE) primme->maxBasisSize = (int)svd->ncv;

    214:   PetscCheck(primme_svds_set_method(ops->method,(primme_preset_method)EPS_PRIMME_DEFAULT_MIN_TIME,PRIMME_DEFAULT_METHOD,primme)>=0,PetscObjectComm((PetscObject)svd),PETSC_ERR_SUP,"PRIMME method not valid");

    216:   svd->mpd = (PetscInt)primme->maxBasisSize;
    217:   svd->ncv = (PetscInt)(primme->locking?svd->nsv:0)+primme->maxBasisSize;
    218:   ops->bs  = (PetscInt)primme->maxBlockSize;

    220:   /* Set workspace */
    221:   PetscCall(SVDAllocateSolution(svd,0));

    223:   /* Prepare auxiliary vectors */
    224:   if (!ops->x) PetscCall(MatCreateVecsEmpty(svd->A,&ops->x,&ops->y));
    225:   PetscFunctionReturn(PETSC_SUCCESS);
    226: }

    228: static PetscErrorCode SVDSolve_PRIMME(SVD svd)
    229: {
    230:   SVD_PRIMME     *ops = (SVD_PRIMME*)svd->data;
    231:   PetscScalar    *svecs, *a;
    232:   PetscInt       i,ierrprimme,ld;
    233:   PetscReal      *svals,*rnorms;

    235:   PetscFunctionBegin;
    236:   /* Reset some parameters left from previous runs */
    237:   ops->primme.aNorm    = 0.0;
    238:   ops->primme.initSize = (int)svd->nini;
    239:   ops->primme.iseed[0] = -1;
    240:   ops->primme.iseed[1] = -1;
    241:   ops->primme.iseed[2] = -1;
    242:   ops->primme.iseed[3] = -1;

    244:   /* Allocating left and right singular vectors contiguously */
    245:   PetscCall(PetscCalloc1(ops->primme.numSvals*(ops->primme.mLocal+ops->primme.nLocal),&svecs));

    247:   /* Call PRIMME solver */
    248:   PetscCall(PetscMalloc2(svd->ncv,&svals,svd->ncv,&rnorms));
    249:   ierrprimme = PRIMME_DRIVER(svals,svecs,rnorms,&ops->primme);
    250:   for (i=0;i<svd->ncv;i++) svd->sigma[i] = svals[i];
    251:   for (i=0;i<svd->ncv;i++) svd->errest[i] = rnorms[i];
    252:   PetscCall(PetscFree2(svals,rnorms));

    254:   /* Copy left and right singular vectors into svd */
    255:   PetscCall(BVGetLeadingDimension(svd->U,&ld));
    256:   PetscCall(BVGetArray(svd->U,&a));
    257:   for (i=0;i<ops->primme.initSize;i++) PetscCall(PetscArraycpy(a+i*ld,svecs+i*ops->primme.mLocal,ops->primme.mLocal));
    258:   PetscCall(BVRestoreArray(svd->U,&a));

    260:   PetscCall(BVGetLeadingDimension(svd->V,&ld));
    261:   PetscCall(BVGetArray(svd->V,&a));
    262:   for (i=0;i<ops->primme.initSize;i++) PetscCall(PetscArraycpy(a+i*ld,svecs+ops->primme.mLocal*ops->primme.initSize+i*ops->primme.nLocal,ops->primme.nLocal));
    263:   PetscCall(BVRestoreArray(svd->V,&a));

    265:   PetscCall(PetscFree(svecs));

    267:   svd->nconv  = ops->primme.initSize >= 0 ? (PetscInt)ops->primme.initSize : 0;
    268:   svd->reason = svd->nconv >= svd->nsv ? SVD_CONVERGED_TOL: SVD_DIVERGED_ITS;
    269:   PetscCall(PetscIntCast(ops->primme.stats.numOuterIterations,&svd->its));

    271:   /* Process PRIMME error code */
    272:   if (ierrprimme != 0) {
    273:     switch (ierrprimme%100) {
    274:       case -1:
    275:         SETERRQ(PetscObjectComm((PetscObject)svd),PETSC_ERR_LIB,"PRIMME library failed with error code=%" PetscInt_FMT ": unexpected error",ierrprimme);
    276:       case -2:
    277:         SETERRQ(PetscObjectComm((PetscObject)svd),PETSC_ERR_LIB,"PRIMME library failed with error code=%" PetscInt_FMT ": allocation error",ierrprimme);
    278:       case -3: /* stop due to maximum number of iterations or matvecs */
    279:         break;
    280:       default:
    281:         PetscCheck(ierrprimme<-39,PetscObjectComm((PetscObject)svd),PETSC_ERR_LIB,"PRIMME library failed with error code=%" PetscInt_FMT ": configuration error; check PRIMME's manual",ierrprimme);
    282:         PetscCheck(ierrprimme>=-39,PetscObjectComm((PetscObject)svd),PETSC_ERR_LIB,"PRIMME library failed with error code=%" PetscInt_FMT ": runtime error; check PRIMME's manual",ierrprimme);
    283:     }
    284:   }
    285:   PetscFunctionReturn(PETSC_SUCCESS);
    286: }

    288: static PetscErrorCode SVDReset_PRIMME(SVD svd)
    289: {
    290:   SVD_PRIMME     *ops = (SVD_PRIMME*)svd->data;

    292:   PetscFunctionBegin;
    293:   primme_svds_free(&ops->primme);
    294:   PetscCall(VecDestroy(&ops->x));
    295:   PetscCall(VecDestroy(&ops->y));
    296:   PetscFunctionReturn(PETSC_SUCCESS);
    297: }

    299: static PetscErrorCode SVDDestroy_PRIMME(SVD svd)
    300: {
    301:   PetscFunctionBegin;
    302:   PetscCall(PetscFree(svd->data));
    303:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMESetBlockSize_C",NULL));
    304:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMEGetBlockSize_C",NULL));
    305:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMESetMethod_C",NULL));
    306:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMEGetMethod_C",NULL));
    307:   PetscFunctionReturn(PETSC_SUCCESS);
    308: }

    310: static PetscErrorCode SVDView_PRIMME(SVD svd,PetscViewer viewer)
    311: {
    312:   PetscBool      isascii;
    313:   SVD_PRIMME     *ctx = (SVD_PRIMME*)svd->data;
    314:   PetscMPIInt    rank;

    316:   PetscFunctionBegin;
    317:   PetscCall(PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&isascii));
    318:   if (isascii) {
    319:     PetscCall(PetscViewerASCIIPrintf(viewer,"  block size=%" PetscInt_FMT "\n",ctx->bs));
    320:     PetscCall(PetscViewerASCIIPrintf(viewer,"  solver method: %s\n",SVDPRIMMEMethods[(SVDPRIMMEMethod)ctx->method]));

    322:     /* Display PRIMME params */
    323:     PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)svd),&rank));
    324:     if (!rank) primme_svds_display_params(ctx->primme);
    325:   }
    326:   PetscFunctionReturn(PETSC_SUCCESS);
    327: }

    329: static PetscErrorCode SVDSetFromOptions_PRIMME(SVD svd,PetscOptionItems PetscOptionsObject)
    330: {
    331:   SVD_PRIMME      *ctx = (SVD_PRIMME*)svd->data;
    332:   PetscInt        bs;
    333:   SVDPRIMMEMethod meth;
    334:   PetscBool       flg;

    336:   PetscFunctionBegin;
    337:   PetscOptionsHeadBegin(PetscOptionsObject,"SVD PRIMME Options");

    339:     PetscCall(PetscOptionsInt("-svd_primme_blocksize","Maximum block size","SVDPRIMMESetBlockSize",ctx->bs,&bs,&flg));
    340:     if (flg) PetscCall(SVDPRIMMESetBlockSize(svd,bs));

    342:     PetscCall(PetscOptionsEnum("-svd_primme_method","Method for solving the singular value problem","SVDPRIMMESetMethod",SVDPRIMMEMethods,(PetscEnum)ctx->method,(PetscEnum*)&meth,&flg));
    343:     if (flg) PetscCall(SVDPRIMMESetMethod(svd,meth));

    345:   PetscOptionsHeadEnd();
    346:   PetscFunctionReturn(PETSC_SUCCESS);
    347: }

    349: static PetscErrorCode SVDPRIMMESetBlockSize_PRIMME(SVD svd,PetscInt bs)
    350: {
    351:   SVD_PRIMME *ops = (SVD_PRIMME*)svd->data;

    353:   PetscFunctionBegin;
    354:   if (bs == PETSC_DEFAULT || bs == PETSC_DECIDE) ops->bs = 0;
    355:   else {
    356:     PetscCheck(bs>0,PetscObjectComm((PetscObject)svd),PETSC_ERR_ARG_OUTOFRANGE,"PRIMME: block size must be positive");
    357:     ops->bs = bs;
    358:   }
    359:   PetscFunctionReturn(PETSC_SUCCESS);
    360: }

    362: /*@
    363:    SVDPRIMMESetBlockSize - The maximum block size that PRIMME will try to use.

    365:    Logically Collective

    367:    Input Parameters:
    368: +  svd - the singular value solver context
    369: -  bs - block size

    371:    Options Database Key:
    372: .  -svd_primme_blocksize bs - sets the maximux allowed block size

    374:    Notes:
    375:    If the block size is not set, the value established by `primme_svds_initialize`
    376:    is used.

    378:    The user should set the block size based on the architecture specifics
    379:    of the target computer, as well as any a priori knowledge of multiplicities.
    380:    The code does NOT require `bs` > 1 to find multiple eigenvalues. For some
    381:    methods, keeping `bs` = 1 yields the best overall performance.

    383:    See the documentation of PRIMME {cite:p}`Sta10` for details.

    385:    Level: advanced

    387: .seealso: [](ch:svd), `SVDPRIMME`, `SVDPRIMMEGetBlockSize()`
    388: @*/
    389: PetscErrorCode SVDPRIMMESetBlockSize(SVD svd,PetscInt bs)
    390: {
    391:   PetscFunctionBegin;
    394:   PetscTryMethod(svd,"SVDPRIMMESetBlockSize_C",(SVD,PetscInt),(svd,bs));
    395:   PetscFunctionReturn(PETSC_SUCCESS);
    396: }

    398: static PetscErrorCode SVDPRIMMEGetBlockSize_PRIMME(SVD svd,PetscInt *bs)
    399: {
    400:   SVD_PRIMME *ops = (SVD_PRIMME*)svd->data;

    402:   PetscFunctionBegin;
    403:   *bs = ops->bs;
    404:   PetscFunctionReturn(PETSC_SUCCESS);
    405: }

    407: /*@
    408:    SVDPRIMMEGetBlockSize - Get the maximum block size the code will try to use.

    410:    Not Collective

    412:    Input Parameter:
    413: .  svd - the singular value solver context

    415:    Output Parameter:
    416: .  bs - returned block size

    418:    Level: advanced

    420: .seealso: [](ch:svd), `SVDPRIMME`, `SVDPRIMMESetBlockSize()`
    421: @*/
    422: PetscErrorCode SVDPRIMMEGetBlockSize(SVD svd,PetscInt *bs)
    423: {
    424:   PetscFunctionBegin;
    426:   PetscAssertPointer(bs,2);
    427:   PetscUseMethod(svd,"SVDPRIMMEGetBlockSize_C",(SVD,PetscInt*),(svd,bs));
    428:   PetscFunctionReturn(PETSC_SUCCESS);
    429: }

    431: static PetscErrorCode SVDPRIMMESetMethod_PRIMME(SVD svd,SVDPRIMMEMethod method)
    432: {
    433:   SVD_PRIMME *ops = (SVD_PRIMME*)svd->data;

    435:   PetscFunctionBegin;
    436:   ops->method = (primme_svds_preset_method)method;
    437:   PetscFunctionReturn(PETSC_SUCCESS);
    438: }

    440: /*@
    441:    SVDPRIMMESetMethod - Sets the method for the PRIMME SVD solver.

    443:    Logically Collective

    445:    Input Parameters:
    446: +  svd - the singular value solver context
    447: -  method - method that will be used by PRIMME

    449:    Options Database Key:
    450: .  -svd_primme_method method - sets the method for the PRIMME SVD solver

    452:    Notes:
    453:    If not set, the method defaults to `SVD_PRIMME_HYBRID`.

    455:    See the documentation of PRIMME {cite:p}`Sta10` for a description of the methods.

    457:    Level: advanced

    459: .seealso: [](ch:svd), `SVDPRIMME`, `SVDPRIMMEGetMethod()`, `SVDPRIMMEMethod`
    460: @*/
    461: PetscErrorCode SVDPRIMMESetMethod(SVD svd,SVDPRIMMEMethod method)
    462: {
    463:   PetscFunctionBegin;
    466:   PetscTryMethod(svd,"SVDPRIMMESetMethod_C",(SVD,SVDPRIMMEMethod),(svd,method));
    467:   PetscFunctionReturn(PETSC_SUCCESS);
    468: }

    470: static PetscErrorCode SVDPRIMMEGetMethod_PRIMME(SVD svd,SVDPRIMMEMethod *method)
    471: {
    472:   SVD_PRIMME *ops = (SVD_PRIMME*)svd->data;

    474:   PetscFunctionBegin;
    475:   *method = (SVDPRIMMEMethod)ops->method;
    476:   PetscFunctionReturn(PETSC_SUCCESS);
    477: }

    479: /*@
    480:    SVDPRIMMEGetMethod - Gets the method for the PRIMME SVD solver.

    482:    Not Collective

    484:    Input Parameter:
    485: .  svd - the singular value solver context

    487:    Output Parameter:
    488: .  method - method that will be used by PRIMME

    490:    Level: advanced

    492: .seealso: [](ch:svd), `SVDPRIMME`, `SVDPRIMMESetMethod()`, `SVDPRIMMEMethod`
    493: @*/
    494: PetscErrorCode SVDPRIMMEGetMethod(SVD svd,SVDPRIMMEMethod *method)
    495: {
    496:   PetscFunctionBegin;
    498:   PetscAssertPointer(method,2);
    499:   PetscUseMethod(svd,"SVDPRIMMEGetMethod_C",(SVD,SVDPRIMMEMethod*),(svd,method));
    500:   PetscFunctionReturn(PETSC_SUCCESS);
    501: }

    503: /*MC
    504:    SVDPRIMME - SVDPRIMME = "primme" - A wrapper to PRIMME {cite:p}`Sta10`.

    506:    Notes:
    507:    Only available for standard SVD problems.

    509:    The PRIMME library provides several singular value solvers. The
    510:    default one is generally a good choice, but the user can select another
    511:    with `SVDPRIMMESetMethod()`.

    513:    Level: beginner

    515: .seealso: [](ch:svd), `SVD`, `SVDType`, `SVDSetType()`
    516: M*/
    517: SLEPC_EXTERN PetscErrorCode SVDCreate_PRIMME(SVD svd)
    518: {
    519:   SVD_PRIMME     *primme;

    521:   PetscFunctionBegin;
    522:   PetscCall(PetscNew(&primme));
    523:   svd->data = (void*)primme;

    525:   primme_svds_initialize(&primme->primme);
    526:   primme->bs = 0;
    527:   primme->method = (primme_svds_preset_method)SVD_PRIMME_HYBRID;
    528:   primme->svd = svd;

    530:   svd->ops->solve          = SVDSolve_PRIMME;
    531:   svd->ops->setup          = SVDSetUp_PRIMME;
    532:   svd->ops->setfromoptions = SVDSetFromOptions_PRIMME;
    533:   svd->ops->destroy        = SVDDestroy_PRIMME;
    534:   svd->ops->reset          = SVDReset_PRIMME;
    535:   svd->ops->view           = SVDView_PRIMME;

    537:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMESetBlockSize_C",SVDPRIMMESetBlockSize_PRIMME));
    538:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMEGetBlockSize_C",SVDPRIMMEGetBlockSize_PRIMME));
    539:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMESetMethod_C",SVDPRIMMESetMethod_PRIMME));
    540:   PetscCall(PetscObjectComposeFunction((PetscObject)svd,"SVDPRIMMEGetMethod_C",SVDPRIMMEGetMethod_PRIMME));
    541:   PetscFunctionReturn(PETSC_SUCCESS);
    542: }