Date: 2016-03-29T14:58:16+00:00

Actual source code: lapack.c
slepc-3.6.3 2016-03-29
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      1: /*
      2:    This file implements a wrapper to the LAPACK eigenvalue subroutines.
      3:    Generalized problems are transformed to standard ones only if necessary.

      5:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      6:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      7:    Copyright (c) 2002-2015, Universitat Politecnica de Valencia, Spain

      9:    This file is part of SLEPc.

     11:    SLEPc is free software: you can redistribute it and/or modify it under  the
     12:    terms of version 3 of the GNU Lesser General Public License as published by
     13:    the Free Software Foundation.

     15:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
     16:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
     17:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
     18:    more details.

     20:    You  should have received a copy of the GNU Lesser General  Public  License
     21:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
     22:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     23: */

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

     29: PetscErrorCode EPSSetUp_LAPACK(EPS eps)
     30: {
     31:   PetscErrorCode ierr,ierra,ierrb;
     32:   PetscBool      isshift,denseok=PETSC_FALSE;
     33:   Mat            A,B,OP,Adense=NULL,Bdense=NULL;
     34:   PetscScalar    shift,*Ap,*Bp;
     35:   PetscInt       i,ld,nmat;
     36:   KSP            ksp;
     37:   PC             pc;
     38:   Vec            v;

     41:   eps->ncv = eps->n;
     42:   if (eps->mpd) { PetscInfo(eps,"Warning: parameter mpd ignored\n"); }
     43:   if (!eps->which) { EPSSetWhichEigenpairs_Default(eps); }
     44:   if (eps->balance!=EPS_BALANCE_NONE) { PetscInfo(eps,"Warning: balancing ignored\n"); }
     45:   if (eps->extraction) { PetscInfo(eps,"Warning: extraction type ignored\n"); }
     46:   EPSAllocateSolution(eps,0);

     48:   /* attempt to get dense representations of A and B separately */
     49:   PetscObjectTypeCompare((PetscObject)eps->st,STSHIFT,&isshift);
     50:   if (isshift) {
     51:     STGetNumMatrices(eps->st,&nmat);
     52:     STGetOperators(eps->st,0,&A);
     53:     if (nmat>1) { STGetOperators(eps->st,1,&B); }
     54:     PetscPushErrorHandler(PetscIgnoreErrorHandler,NULL);
     55:     ierra = SlepcMatConvertSeqDense(A,&Adense);
     56:     if (eps->isgeneralized) {
     57:       ierrb = SlepcMatConvertSeqDense(B,&Bdense);
     58:     } else {
     59:       ierrb = 0;
     60:     }
     61:     PetscPopErrorHandler();
     62:     denseok = (ierra == 0 && ierrb == 0)? PETSC_TRUE: PETSC_FALSE;
     63:   }

     65:   /* setup DS */
     66:   if (denseok) {
     67:     if (eps->isgeneralized) {
     68:       if (eps->ishermitian) {
     69:         if (eps->ispositive) {
     70:           DSSetType(eps->ds,DSGHEP);
     71:         } else {
     72:           DSSetType(eps->ds,DSGNHEP); /* TODO: should be DSGHIEP */
     73:         }
     74:       } else {
     75:         DSSetType(eps->ds,DSGNHEP);
     76:       }
     77:     } else {
     78:       if (eps->ishermitian) {
     79:         DSSetType(eps->ds,DSHEP);
     80:       } else {
     81:         DSSetType(eps->ds,DSNHEP);
     82:       }
     83:     }
     84:   } else {
     85:     DSSetType(eps->ds,DSNHEP);
     86:   }
     87:   DSAllocate(eps->ds,eps->ncv);
     88:   DSGetLeadingDimension(eps->ds,&ld);
     89:   DSSetDimensions(eps->ds,eps->ncv,0,0,0);

     91:   if (denseok) {
     92:     STGetShift(eps->st,&shift);
     93:     if (shift != 0.0) {
     94:       MatShift(Adense,shift);
     95:     }
     96:     /* use dummy pc and ksp to avoid problems when B is not positive definite */
     97:     STGetKSP(eps->st,&ksp);
     98:     KSPSetType(ksp,KSPPREONLY);
     99:     KSPGetPC(ksp,&pc);
    100:     PCSetType(pc,PCNONE);
    101:   } else {
    102:     PetscInfo(eps,"Using slow explicit operator\n");
    103:     STComputeExplicitOperator(eps->st,&OP);
    104:     MatDestroy(&Adense);
    105:     SlepcMatConvertSeqDense(OP,&Adense);
    106:   }

    108:   /* fill DS matrices */
    109:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,ld,NULL,&v);
    110:   DSGetArray(eps->ds,DS_MAT_A,&Ap);
    111:   for (i=0;i<ld;i++) {
    112:     VecPlaceArray(v,Ap+i*ld);
    113:     MatGetColumnVector(Adense,v,i);
    114:     VecResetArray(v);
    115:   }
    116:   DSRestoreArray(eps->ds,DS_MAT_A,&Ap);
    117:   if (denseok && eps->isgeneralized) {
    118:     DSGetArray(eps->ds,DS_MAT_B,&Bp);
    119:     for (i=0;i<ld;i++) {
    120:       VecPlaceArray(v,Bp+i*ld);
    121:       MatGetColumnVector(Bdense,v,i);
    122:       VecResetArray(v);
    123:     }
    124:     DSRestoreArray(eps->ds,DS_MAT_B,&Bp);
    125:   }
    126:   VecDestroy(&v);
    127:   MatDestroy(&Adense);
    128:   if (!denseok) { MatDestroy(&OP); }
    129:   if (denseok && eps->isgeneralized) { MatDestroy(&Bdense); }
    130:   return(0);
    131: }

    135: PetscErrorCode EPSSolve_LAPACK(EPS eps)
    136: {
    138:   PetscInt       n=eps->n,i,low,high;
    139:   PetscScalar    *array,*pX;
    140:   Vec            v;

    143:   DSSolve(eps->ds,eps->eigr,eps->eigi);
    144:   DSSort(eps->ds,eps->eigr,eps->eigi,NULL,NULL,NULL);

    146:   /* right eigenvectors */
    147:   DSVectors(eps->ds,DS_MAT_X,NULL,NULL);
    148:   DSGetArray(eps->ds,DS_MAT_X,&pX);
    149:   for (i=0;i<eps->ncv;i++) {
    150:     BVGetColumn(eps->V,i,&v);
    151:     VecGetOwnershipRange(v,&low,&high);
    152:     VecGetArray(v,&array);
    153:     PetscMemcpy(array,pX+i*n+low,(high-low)*sizeof(PetscScalar));
    154:     VecRestoreArray(v,&array);
    155:     BVRestoreColumn(eps->V,i,&v);
    156:   }
    157:   DSRestoreArray(eps->ds,DS_MAT_X,&pX);

    159:   eps->nconv  = eps->ncv;
    160:   eps->its    = 1;
    161:   eps->reason = EPS_CONVERGED_TOL;
    162:   return(0);
    163: }

    167: PETSC_EXTERN PetscErrorCode EPSCreate_LAPACK(EPS eps)
    168: {
    170:   eps->ops->solve                = EPSSolve_LAPACK;
    171:   eps->ops->setup                = EPSSetUp_LAPACK;
    172:   eps->ops->backtransform        = EPSBackTransform_Default;
    173:   return(0);
    174: }