Date: 2023-01-26T12:18:39+00:00

Actual source code: lapack.c
slepc-3.18.2 2023-01-26
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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: PetscErrorCode EPSSetUp_LAPACK(EPS eps)
     18: {
     19:   PetscErrorCode 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:   eps->ncv = eps->n;
     28:   if (eps->mpd!=PETSC_DEFAULT) PetscInfo(eps,"Warning: parameter mpd ignored\n");
     29:   if (eps->max_it==PETSC_DEFAULT) eps->max_it = 1;
     30:   if (!eps->which) EPSSetWhichEigenpairs_Default(eps);
     32:   EPSCheckUnsupported(eps,EPS_FEATURE_BALANCE | EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION | EPS_FEATURE_STOPPING);
     33:   EPSCheckIgnored(eps,EPS_FEATURE_EXTRACTION | EPS_FEATURE_CONVERGENCE);
     34:   EPSAllocateSolution(eps,0);

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

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

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

     99:   /* fill DS matrices */
    100:   DSGetMat(eps->ds,DS_MAT_A,&Ads);
    101:   MatCopy(Adense,Ads,SAME_NONZERO_PATTERN);
    102:   DSRestoreMat(eps->ds,DS_MAT_A,&Ads);
    103:   if (denseok && eps->isgeneralized) {
    104:     DSGetMat(eps->ds,DS_MAT_B,&Bds);
    105:     MatCopy(Bdense,Bds,SAME_NONZERO_PATTERN);
    106:     DSRestoreMat(eps->ds,DS_MAT_B,&Bds);
    107:   }
    108:   DSSetState(eps->ds,DS_STATE_RAW);
    109:   MatDestroy(&Adense);
    110:   MatDestroy(&Bdense);
    111:   return 0;
    112: }

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

    120:   DSSolve(eps->ds,eps->eigr,eps->eigi);
    121:   DSSort(eps->ds,eps->eigr,eps->eigi,NULL,NULL,NULL);
    122:   DSSynchronize(eps->ds,eps->eigr,eps->eigi);

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

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

    152:   eps->nconv  = eps->ncv;
    153:   eps->its    = 1;
    154:   eps->reason = EPS_CONVERGED_TOL;
    155:   return 0;
    156: }

    158: SLEPC_EXTERN PetscErrorCode EPSCreate_LAPACK(EPS eps)
    159: {
    160:   eps->useds = PETSC_TRUE;
    161:   eps->categ = EPS_CATEGORY_OTHER;

    163:   eps->ops->solve          = EPSSolve_LAPACK;
    164:   eps->ops->setup          = EPSSetUp_LAPACK;
    165:   eps->ops->setupsort      = EPSSetUpSort_Default;
    166:   eps->ops->backtransform  = EPSBackTransform_Default;
    167:   return 0;
    168: }