Actual source code: lapack.c

  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) 2002-2013, 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>     /*I "slepceps.h" I*/
 26: #include <slepcblaslapack.h>

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

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

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

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

 92:   if (denseok) {
 93:     STGetShift(eps->st,&shift);
 94:     if (shift != 0.0) {
 95:       MatShift(Adense,shift);
 96:     }
 97:     /* use dummy pc and ksp to avoid problems when B is not positive definite */
 98:     STGetKSP(eps->st,&ksp);
 99:     KSPSetType(ksp,KSPPREONLY);
100:     KSPGetPC(ksp,&pc);
101:     PCSetType(pc,PCNONE);
102:   } else {
103:     PetscInfo(eps,"Using slow explicit operator\n");
104:     STComputeExplicitOperator(eps->st,&OP);
105:     MatDestroy(&Adense);
106:     SlepcMatConvertSeqDense(OP,&Adense);
107:   }

109:   /* fill DS matrices */
110:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,ld,NULL,&v);
111:   DSGetArray(eps->ds,DS_MAT_A,&Ap);
112:   for (i=0;i<ld;i++) {
113:     VecPlaceArray(v,Ap+i*ld);
114:     MatGetColumnVector(Adense,v,i);
115:     VecResetArray(v);
116:   }
117:   DSRestoreArray(eps->ds,DS_MAT_A,&Ap);
118:   if (denseok && eps->isgeneralized) {
119:     DSGetArray(eps->ds,DS_MAT_B,&Bp);
120:     for (i=0;i<ld;i++) {
121:       VecPlaceArray(v,Bp+i*ld);
122:       MatGetColumnVector(Bdense,v,i);
123:       VecResetArray(v);
124:     }
125:     DSRestoreArray(eps->ds,DS_MAT_B,&Bp);
126:   }
127:   VecDestroy(&v);
128:   MatDestroy(&Adense);
129:   if (!denseok) { MatDestroy(&OP); }
130:   if (denseok && eps->isgeneralized) { MatDestroy(&Bdense); }
131:   return(0);
132: }

136: PetscErrorCode EPSSolve_LAPACK(EPS eps)
137: {
139:   PetscInt       n=eps->n,i,low,high;
140:   PetscScalar    *array,*pX,*pY;

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:     VecGetOwnershipRange(eps->V[i],&low,&high);
151:     VecGetArray(eps->V[i],&array);
152:     PetscMemcpy(array,pX+i*n+low,(high-low)*sizeof(PetscScalar));
153:     VecRestoreArray(eps->V[i],&array);
154:   }
155:   DSRestoreArray(eps->ds,DS_MAT_X,&pX);

157:   /* left eigenvectors */
158:   if (eps->leftvecs) {
159:     DSVectors(eps->ds,DS_MAT_Y,NULL,NULL);
160:     DSGetArray(eps->ds,DS_MAT_Y,&pY);
161:     for (i=0;i<eps->ncv;i++) {
162:       VecGetOwnershipRange(eps->W[i],&low,&high);
163:       VecGetArray(eps->W[i],&array);
164:       PetscMemcpy(array,pY+i*n+low,(high-low)*sizeof(PetscScalar));
165:       VecRestoreArray(eps->W[i],&array);
166:     }
167:     DSRestoreArray(eps->ds,DS_MAT_Y,&pY);
168:   }
169:   eps->nconv  = eps->ncv;
170:   eps->its    = 1;
171:   eps->reason = EPS_CONVERGED_TOL;
172:   return(0);
173: }

177: PetscErrorCode EPSReset_LAPACK(EPS eps)
178: {

182:   EPSFreeSolution(eps);
183:   return(0);
184: }

188: PETSC_EXTERN PetscErrorCode EPSCreate_LAPACK(EPS eps)
189: {
191:   eps->ops->solve                = EPSSolve_LAPACK;
192:   eps->ops->setup                = EPSSetUp_LAPACK;
193:   eps->ops->reset                = EPSReset_LAPACK;
194:   eps->ops->backtransform        = EPSBackTransform_Default;
195:   eps->ops->computevectors       = EPSComputeVectors_Default;
196:   return(0);
197: }