Actual source code: lapack.c
slepc-3.21.1 2024-04-26
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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:    This file implements a wrapper to the LAPACK eigenvalue subroutines.
     12:    Generalized problems are transformed to standard ones only if necessary.
     13: */

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

     17: static PetscErrorCode EPSSetUp_LAPACK(EPS eps)
     18: {
     19:   int            ierra,ierrb;
     20:   PetscBool      isshift,flg,denseok=PETSC_FALSE;
     21:   Mat            A,B,OP,shell,Ar,Br,Adense=NULL,Bdense=NULL,Ads,Bds;
     22:   PetscScalar    shift;
     23:   PetscInt       nmat;
     24:   KSP            ksp;
     25:   PC             pc;

     27:   PetscFunctionBegin;
     28:   eps->ncv = eps->n;
     29:   if (eps->mpd!=PETSC_DEFAULT) PetscCall(PetscInfo(eps,"Warning: parameter mpd ignored\n"));
     30:   if (eps->max_it==PETSC_DEFAULT) eps->max_it = 1;
     31:   if (!eps->which) PetscCall(EPSSetWhichEigenpairs_Default(eps));
     32:   PetscCheck(eps->which!=EPS_ALL || eps->inta==eps->intb,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"This solver does not support interval computation");
     33:   EPSCheckUnsupported(eps,EPS_FEATURE_BALANCE | EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION | EPS_FEATURE_STOPPING);
     34:   EPSCheckIgnored(eps,EPS_FEATURE_EXTRACTION | EPS_FEATURE_CONVERGENCE);
     35:   PetscCall(EPSAllocateSolution(eps,0));

     37:   /* attempt to get dense representations of A and B separately */
     38:   PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STSHIFT,&isshift));
     39:   if (isshift) {
     40:     PetscCall(STGetNumMatrices(eps->st,&nmat));
     41:     PetscCall(STGetMatrix(eps->st,0,&A));
     42:     PetscCall(MatHasOperation(A,MATOP_CREATE_SUBMATRICES,&flg));
     43:     if (flg) {
     44:       PetscCall(PetscPushErrorHandler(PetscReturnErrorHandler,NULL));
     45:       ierra  = MatCreateRedundantMatrix(A,0,PETSC_COMM_SELF,MAT_INITIAL_MATRIX,&Ar);
     46:       if (!ierra) ierra |= MatConvert(Ar,MATSEQDENSE,MAT_INITIAL_MATRIX,&Adense);
     47:       ierra |= MatDestroy(&Ar);
     48:       PetscCall(PetscPopErrorHandler());
     49:     } else ierra = 1;
     50:     if (nmat>1) {
     51:       PetscCall(STGetMatrix(eps->st,1,&B));
     52:       PetscCall(MatHasOperation(B,MATOP_CREATE_SUBMATRICES,&flg));
     53:       if (flg) {
     54:         PetscCall(PetscPushErrorHandler(PetscReturnErrorHandler,NULL));
     55:         ierrb  = MatCreateRedundantMatrix(B,0,PETSC_COMM_SELF,MAT_INITIAL_MATRIX,&Br);
     56:         if (!ierrb) ierrb |= MatConvert(Br,MATSEQDENSE,MAT_INITIAL_MATRIX,&Bdense);
     57:         ierrb |= MatDestroy(&Br);
     58:         PetscCall(PetscPopErrorHandler());
     59:       } else ierrb = 1;
     60:     } else ierrb = 0;
     61:     denseok = PetscNot(ierra || ierrb);
     62:   }

     64:   /* setup DS */
     65:   if (denseok) {
     66:     if (eps->isgeneralized) {
     67:       if (eps->ishermitian) {
     68:         if (eps->ispositive) PetscCall(DSSetType(eps->ds,DSGHEP));
     69:         else PetscCall(DSSetType(eps->ds,DSGNHEP)); /* TODO: should be DSGHIEP */
     70:       } else PetscCall(DSSetType(eps->ds,DSGNHEP));
     71:     } else {
     72:       if (eps->ishermitian) PetscCall(DSSetType(eps->ds,DSHEP));
     73:       else PetscCall(DSSetType(eps->ds,DSNHEP));
     74:     }
     75:   } else PetscCall(DSSetType(eps->ds,DSNHEP));
     76:   PetscCall(DSAllocate(eps->ds,eps->ncv));
     77:   PetscCall(DSSetDimensions(eps->ds,eps->ncv,0,0));

     79:   if (denseok) {
     80:     PetscCall(STGetShift(eps->st,&shift));
     81:     if (shift != 0.0) {
     82:       if (nmat>1) PetscCall(MatAXPY(Adense,-shift,Bdense,SAME_NONZERO_PATTERN));
     83:       else PetscCall(MatShift(Adense,-shift));
     84:     }
     85:     /* use dummy pc and ksp to avoid problems when B is not positive definite */
     86:     PetscCall(STGetKSP(eps->st,&ksp));
     87:     PetscCall(KSPSetType(ksp,KSPPREONLY));
     88:     PetscCall(KSPGetPC(ksp,&pc));
     89:     PetscCall(PCSetType(pc,PCNONE));
     90:   } else {
     91:     PetscCall(PetscInfo(eps,"Using slow explicit operator\n"));
     92:     PetscCall(STGetOperator(eps->st,&shell));
     93:     PetscCall(MatComputeOperator(shell,MATDENSE,&OP));
     94:     PetscCall(STRestoreOperator(eps->st,&shell));
     95:     PetscCall(MatDestroy(&Adense));
     96:     PetscCall(MatCreateRedundantMatrix(OP,0,PETSC_COMM_SELF,MAT_INITIAL_MATRIX,&Adense));
     97:     PetscCall(MatDestroy(&OP));
     98:   }

    100:   /* fill DS matrices */
    101:   PetscCall(DSGetMat(eps->ds,DS_MAT_A,&Ads));
    102:   PetscCall(MatCopy(Adense,Ads,SAME_NONZERO_PATTERN));
    103:   PetscCall(DSRestoreMat(eps->ds,DS_MAT_A,&Ads));
    104:   if (denseok && eps->isgeneralized) {
    105:     PetscCall(DSGetMat(eps->ds,DS_MAT_B,&Bds));
    106:     PetscCall(MatCopy(Bdense,Bds,SAME_NONZERO_PATTERN));
    107:     PetscCall(DSRestoreMat(eps->ds,DS_MAT_B,&Bds));
    108:   }
    109:   PetscCall(DSSetState(eps->ds,DS_STATE_RAW));
    110:   PetscCall(MatDestroy(&Adense));
    111:   PetscCall(MatDestroy(&Bdense));
    112:   PetscFunctionReturn(PETSC_SUCCESS);
    113: }

    115: static PetscErrorCode EPSSolve_LAPACK(EPS eps)
    116: {
    117:   PetscInt       n=eps->n,i,low,high;
    118:   PetscScalar    *array,*pX,*pY;
    119:   Vec            v,w;

    121:   PetscFunctionBegin;
    122:   PetscCall(DSSolve(eps->ds,eps->eigr,eps->eigi));
    123:   PetscCall(DSSort(eps->ds,eps->eigr,eps->eigi,NULL,NULL,NULL));
    124:   PetscCall(DSSynchronize(eps->ds,eps->eigr,eps->eigi));

    126:   /* right eigenvectors */
    127:   PetscCall(DSVectors(eps->ds,DS_MAT_X,NULL,NULL));
    128:   PetscCall(DSGetArray(eps->ds,DS_MAT_X,&pX));
    129:   for (i=0;i<eps->ncv;i++) {
    130:     PetscCall(BVGetColumn(eps->V,i,&v));
    131:     PetscCall(VecGetOwnershipRange(v,&low,&high));
    132:     PetscCall(VecGetArray(v,&array));
    133:     PetscCall(PetscArraycpy(array,pX+i*n+low,high-low));
    134:     PetscCall(VecRestoreArray(v,&array));
    135:     PetscCall(BVRestoreColumn(eps->V,i,&v));
    136:   }
    137:   PetscCall(DSRestoreArray(eps->ds,DS_MAT_X,&pX));

    139:   /* left eigenvectors */
    140:   if (eps->twosided) {
    141:     PetscCall(DSVectors(eps->ds,DS_MAT_Y,NULL,NULL));
    142:     PetscCall(DSGetArray(eps->ds,DS_MAT_Y,&pY));
    143:     for (i=0;i<eps->ncv;i++) {
    144:       PetscCall(BVGetColumn(eps->W,i,&w));
    145:       PetscCall(VecGetOwnershipRange(w,&low,&high));
    146:       PetscCall(VecGetArray(w,&array));
    147:       PetscCall(PetscArraycpy(array,pY+i*n+low,high-low));
    148:       PetscCall(VecRestoreArray(w,&array));
    149:       PetscCall(BVRestoreColumn(eps->W,i,&w));
    150:     }
    151:     PetscCall(DSRestoreArray(eps->ds,DS_MAT_Y,&pY));
    152:   }

    154:   eps->nconv  = eps->ncv;
    155:   eps->its    = 1;
    156:   eps->reason = EPS_CONVERGED_TOL;
    157:   PetscFunctionReturn(PETSC_SUCCESS);
    158: }

    160: SLEPC_EXTERN PetscErrorCode EPSCreate_LAPACK(EPS eps)
    161: {
    162:   PetscFunctionBegin;
    163:   eps->useds = PETSC_TRUE;
    164:   eps->categ = EPS_CATEGORY_OTHER;

    166:   eps->ops->solve          = EPSSolve_LAPACK;
    167:   eps->ops->setup          = EPSSetUp_LAPACK;
    168:   eps->ops->setupsort      = EPSSetUpSort_Default;
    169:   eps->ops->backtransform  = EPSBackTransform_Default;
    170:   PetscFunctionReturn(PETSC_SUCCESS);
    171: }