Date: 2026-03-09T09:12:30+00:00

Actual source code: scalapack.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 eigensolvers in ScaLAPACK.
     12: */

     14: #include <slepc/private/epsimpl.h>
     15: #include <slepc/private/slepcscalapack.h>

     17: typedef struct {
     18:   Mat As,Bs;        /* converted matrices */
     19: } EPS_ScaLAPACK;

     21: static PetscErrorCode EPSSetUp_ScaLAPACK(EPS eps)
     22: {
     23:   EPS_ScaLAPACK  *ctx = (EPS_ScaLAPACK*)eps->data;
     24:   Mat            A,B;
     25:   PetscInt       nmat;
     26:   PetscBool      isshift;
     27:   PetscScalar    shift;

     29:   PetscFunctionBegin;
     30:   EPSCheckHermitianDefinite(eps);
     31:   EPSCheckNotStructured(eps);
     32:   PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STSHIFT,&isshift));
     33:   PetscCheck(isshift,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"This solver does not support spectral transformations");
     34:   if (eps->nev==0) eps->nev = 1;
     35:   eps->ncv = eps->n;
     36:   if (eps->mpd!=PETSC_DETERMINE) PetscCall(PetscInfo(eps,"Warning: parameter mpd ignored\n"));
     37:   if (eps->max_it==PETSC_DETERMINE) eps->max_it = 1;
     38:   if (!eps->which) PetscCall(EPSSetWhichEigenpairs_Default(eps));
     39:   PetscCheck(eps->which!=EPS_ALL || eps->inta==eps->intb,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"This solver does not support interval computation");
     40:   EPSCheckUnsupported(eps,EPS_FEATURE_BALANCE | EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION);
     41:   EPSCheckIgnored(eps,EPS_FEATURE_EXTRACTION | EPS_FEATURE_CONVERGENCE | EPS_FEATURE_STOPPING);
     42:   PetscCall(EPSAllocateSolution(eps,0));

     44:   /* convert matrices */
     45:   PetscCall(MatDestroy(&ctx->As));
     46:   PetscCall(MatDestroy(&ctx->Bs));
     47:   PetscCall(STGetNumMatrices(eps->st,&nmat));
     48:   PetscCall(STGetMatrix(eps->st,0,&A));
     49:   PetscCall(MatConvert(A,MATSCALAPACK,MAT_INITIAL_MATRIX,&ctx->As));
     50:   if (nmat>1) {
     51:     PetscCall(STGetMatrix(eps->st,1,&B));
     52:     PetscCall(MatConvert(B,MATSCALAPACK,MAT_INITIAL_MATRIX,&ctx->Bs));
     53:   }
     54:   PetscCall(STGetShift(eps->st,&shift));
     55:   if (shift != 0.0) {
     56:     if (nmat>1) PetscCall(MatAXPY(ctx->As,-shift,ctx->Bs,SAME_NONZERO_PATTERN));
     57:     else PetscCall(MatShift(ctx->As,-shift));
     58:   }
     59:   PetscFunctionReturn(PETSC_SUCCESS);
     60: }

     62: static PetscErrorCode EPSSolve_ScaLAPACK(EPS eps)
     63: {
     64:   EPS_ScaLAPACK  *ctx = (EPS_ScaLAPACK*)eps->data;
     65:   Mat            A = ctx->As,B = ctx->Bs,Q,V;
     66:   Mat_ScaLAPACK  *a = (Mat_ScaLAPACK*)A->data,*b,*q;
     67:   PetscReal      rdummy=0.0,abstol=0.0,*gap=NULL,orfac=-1.0,*w = eps->errest;  /* used to store real eigenvalues */
     68:   PetscScalar    *work,minlwork[3];
     69:   PetscBLASInt   i,m,info,idummy=0,lwork=-1,liwork=-1,minliwork,*iwork,*ifail=NULL,*iclustr=NULL,one=1;
     70: #if defined(PETSC_USE_COMPLEX)
     71:   PetscReal      *rwork,minlrwork[3];
     72:   PetscBLASInt   lrwork=-1;
     73: #endif

     75:   PetscFunctionBegin;
     76:   PetscCall(MatDuplicate(A,MAT_DO_NOT_COPY_VALUES,&Q));
     77:   PetscCall(PetscFPTrapPush(PETSC_FP_TRAP_OFF));
     78:   q = (Mat_ScaLAPACK*)Q->data;

     80:   if (B) {

     82:     b = (Mat_ScaLAPACK*)B->data;
     83:     PetscCall(PetscMalloc3(a->grid->nprow*a->grid->npcol,&gap,a->N,&ifail,2*a->grid->nprow*a->grid->npcol,&iclustr));
     84: #if !defined(PETSC_USE_COMPLEX)
     85:     /* allocate workspace */
     86:     PetscCallBLAS("SCALAPACKsygvx",SCALAPACKsygvx_(&one,"V","A","L",&a->N,a->loc,&one,&one,a->desc,b->loc,&one,&one,b->desc,&rdummy,&rdummy,&idummy,&idummy,&abstol,&m,&idummy,w,&orfac,q->loc,&one,&one,q->desc,minlwork,&lwork,&minliwork,&liwork,ifail,iclustr,gap,&info));
     87:     PetscCheckScaLapackInfo("sygvx",info);
     88:     PetscCall(PetscBLASIntCast((PetscInt)minlwork[0],&lwork));
     89:     liwork = minliwork;
     90:     /* call computational routine */
     91:     PetscCall(PetscMalloc2(lwork,&work,liwork,&iwork));
     92:     PetscCallBLAS("SCALAPACKsygvx",SCALAPACKsygvx_(&one,"V","A","L",&a->N,a->loc,&one,&one,a->desc,b->loc,&one,&one,b->desc,&rdummy,&rdummy,&idummy,&idummy,&abstol,&m,&idummy,w,&orfac,q->loc,&one,&one,q->desc,work,&lwork,iwork,&liwork,ifail,iclustr,gap,&info));
     93:     PetscCheckScaLapackInfo("sygvx",info);
     94:     PetscCall(PetscFree2(work,iwork));
     95: #else
     96:     /* allocate workspace */
     97:     PetscCallBLAS("SCALAPACKsygvx",SCALAPACKsygvx_(&one,"V","A","L",&a->N,a->loc,&one,&one,a->desc,b->loc,&one,&one,b->desc,&rdummy,&rdummy,&idummy,&idummy,&abstol,&m,&idummy,w,&orfac,q->loc,&one,&one,q->desc,minlwork,&lwork,minlrwork,&lrwork,&minliwork,&liwork,ifail,iclustr,gap,&info));
     98:     PetscCheckScaLapackInfo("sygvx",info);
     99:     PetscCall(PetscBLASIntCast((PetscInt)PetscRealPart(minlwork[0]),&lwork));
    100:     PetscCall(PetscBLASIntCast((PetscInt)minlrwork[0],&lrwork));
    101:     lrwork += a->N*a->N;
    102:     liwork = minliwork;
    103:     /* call computational routine */
    104:     PetscCall(PetscMalloc3(lwork,&work,lrwork,&rwork,liwork,&iwork));
    105:     PetscCallBLAS("SCALAPACKsygvx",SCALAPACKsygvx_(&one,"V","A","L",&a->N,a->loc,&one,&one,a->desc,b->loc,&one,&one,b->desc,&rdummy,&rdummy,&idummy,&idummy,&abstol,&m,&idummy,w,&orfac,q->loc,&one,&one,q->desc,work,&lwork,rwork,&lrwork,iwork,&liwork,ifail,iclustr,gap,&info));
    106:     PetscCheckScaLapackInfo("sygvx",info);
    107:     PetscCall(PetscFree3(work,rwork,iwork));
    108: #endif
    109:     PetscCall(PetscFree3(gap,ifail,iclustr));

    111:   } else {

    113: #if !defined(PETSC_USE_COMPLEX)
    114:     /* allocate workspace */
    115:     PetscCallBLAS("SCALAPACKsyev",SCALAPACKsyev_("V","L",&a->N,a->loc,&one,&one,a->desc,w,q->loc,&one,&one,q->desc,minlwork,&lwork,&info));
    116:     PetscCheckScaLapackInfo("syev",info);
    117:     PetscCall(PetscBLASIntCast((PetscInt)minlwork[0],&lwork));
    118:     PetscCall(PetscMalloc1(lwork,&work));
    119:     /* call computational routine */
    120:     PetscCallBLAS("SCALAPACKsyev",SCALAPACKsyev_("V","L",&a->N,a->loc,&one,&one,a->desc,w,q->loc,&one,&one,q->desc,work,&lwork,&info));
    121:     PetscCheckScaLapackInfo("syev",info);
    122:     PetscCall(PetscFree(work));
    123: #else
    124:     /* allocate workspace */
    125:     PetscCallBLAS("SCALAPACKsyev",SCALAPACKsyev_("V","L",&a->N,a->loc,&one,&one,a->desc,w,q->loc,&one,&one,q->desc,minlwork,&lwork,minlrwork,&lrwork,&info));
    126:     PetscCheckScaLapackInfo("syev",info);
    127:     PetscCall(PetscBLASIntCast((PetscInt)PetscRealPart(minlwork[0]),&lwork));
    128:     lrwork = 4*a->N;  /* PetscCall(PetscBLASIntCast((PetscInt)minlrwork[0],&lrwork)); */
    129:     PetscCall(PetscMalloc2(lwork,&work,lrwork,&rwork));
    130:     /* call computational routine */
    131:     PetscCallBLAS("SCALAPACKsyev",SCALAPACKsyev_("V","L",&a->N,a->loc,&one,&one,a->desc,w,q->loc,&one,&one,q->desc,work,&lwork,rwork,&lrwork,&info));
    132:     PetscCheckScaLapackInfo("syev",info);
    133:     PetscCall(PetscFree2(work,rwork));
    134: #endif

    136:   }
    137:   PetscCall(PetscFPTrapPop());

    139:   for (i=0;i<eps->ncv;i++) {
    140:     eps->eigr[i]   = eps->errest[i];
    141:     eps->errest[i] = PETSC_MACHINE_EPSILON;
    142:   }

    144:   PetscCall(BVGetMat(eps->V,&V));
    145:   PetscCall(MatConvert(Q,MATDENSE,MAT_REUSE_MATRIX,&V));
    146:   PetscCall(BVRestoreMat(eps->V,&V));
    147:   PetscCall(MatDestroy(&Q));

    149:   eps->nconv  = eps->ncv;
    150:   eps->its    = 1;
    151:   eps->reason = EPS_CONVERGED_TOL;
    152:   PetscFunctionReturn(PETSC_SUCCESS);
    153: }

    155: static PetscErrorCode EPSDestroy_ScaLAPACK(EPS eps)
    156: {
    157:   PetscFunctionBegin;
    158:   PetscCall(PetscFree(eps->data));
    159:   PetscFunctionReturn(PETSC_SUCCESS);
    160: }

    162: static PetscErrorCode EPSReset_ScaLAPACK(EPS eps)
    163: {
    164:   EPS_ScaLAPACK  *ctx = (EPS_ScaLAPACK*)eps->data;

    166:   PetscFunctionBegin;
    167:   PetscCall(MatDestroy(&ctx->As));
    168:   PetscCall(MatDestroy(&ctx->Bs));
    169:   PetscFunctionReturn(PETSC_SUCCESS);
    170: }

    172: /*MC
    173:    EPSSCALAPACK - EPSSCALAPACK = "scalapack" - A wrapper to ScaLAPACK
    174:    eigensolvers {cite:p}`Bla97`.

    176:    Notes:
    177:    Only available for Hermitian problems, using subroutines `pdsyev` and
    178:    `pdsygvx` and the analogs for other precisions.

    180:    This is a direct eigensolver, that is, the full spectrum is computed.
    181:    The computation involves redistributing the matrices from PETSc storage
    182:    to ScaLAPACK distribution, and vice versa (this is done automatically
    183:    by SLEPc). Alternatively, the user may create the problem matrices
    184:    already with type `MATSCALAPACK`.

    186:    Level: beginner

    188: .seealso: [](ch:eps), `EPS`, `EPSType`, `EPSSetType()`
    189: M*/
    190: SLEPC_EXTERN PetscErrorCode EPSCreate_ScaLAPACK(EPS eps)
    191: {
    192:   EPS_ScaLAPACK  *ctx;

    194:   PetscFunctionBegin;
    195:   PetscCall(PetscNew(&ctx));
    196:   eps->data = (void*)ctx;

    198:   eps->categ = EPS_CATEGORY_OTHER;

    200:   eps->ops->solve          = EPSSolve_ScaLAPACK;
    201:   eps->ops->setup          = EPSSetUp_ScaLAPACK;
    202:   eps->ops->setupsort      = EPSSetUpSort_Basic;
    203:   eps->ops->destroy        = EPSDestroy_ScaLAPACK;
    204:   eps->ops->reset          = EPSReset_ScaLAPACK;
    205:   eps->ops->backtransform  = EPSBackTransform_Default;
    206:   eps->ops->setdefaultst   = EPSSetDefaultST_NoFactor;
    207:   PetscFunctionReturn(PETSC_SUCCESS);
    208: }