Actual source code: lapack.c

slepc-3.23.1 2025-05-01
Report Typos and Errors
  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:   if (eps->nev==0) eps->nev = 1;
 29:   eps->ncv = eps->n;
 30:   if (eps->mpd!=PETSC_DETERMINE) PetscCall(PetscInfo(eps,"Warning: parameter mpd ignored\n"));
 31:   if (eps->max_it==PETSC_DETERMINE) eps->max_it = 1;
 32:   if (!eps->which) PetscCall(EPSSetWhichEigenpairs_Default(eps));
 33:   PetscCheck(eps->which!=EPS_ALL || eps->inta==eps->intb,PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"This solver does not support interval computation");
 34:   EPSCheckUnsupported(eps,EPS_FEATURE_BALANCE | EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION);
 35:   EPSCheckIgnored(eps,EPS_FEATURE_EXTRACTION | EPS_FEATURE_CONVERGENCE | EPS_FEATURE_STOPPING);
 36:   PetscCall(EPSAllocateSolution(eps,0));

 38:   /* attempt to get dense representations of A and B separately */
 39:   PetscCall(PetscObjectTypeCompare((PetscObject)eps->st,STSHIFT,&isshift));
 40:   if (isshift) {
 41:     PetscCall(STGetNumMatrices(eps->st,&nmat));
 42:     PetscCall(STGetMatrix(eps->st,0,&A));
 43:     PetscCall(MatHasOperation(A,MATOP_CREATE_SUBMATRICES,&flg));
 44:     if (flg) {
 45:       PetscCall(PetscPushErrorHandler(PetscReturnErrorHandler,NULL));
 46:       ierra  = MatCreateRedundantMatrix(A,0,PETSC_COMM_SELF,MAT_INITIAL_MATRIX,&Ar);
 47:       if (!ierra) ierra |= MatConvert(Ar,MATSEQDENSE,MAT_INITIAL_MATRIX,&Adense);
 48:       ierra |= MatDestroy(&Ar);
 49:       PetscCall(PetscPopErrorHandler());
 50:     } else ierra = 1;
 51:     if (nmat>1) {
 52:       PetscCall(STGetMatrix(eps->st,1,&B));
 53:       PetscCall(MatHasOperation(B,MATOP_CREATE_SUBMATRICES,&flg));
 54:       if (flg) {
 55:         PetscCall(PetscPushErrorHandler(PetscReturnErrorHandler,NULL));
 56:         ierrb  = MatCreateRedundantMatrix(B,0,PETSC_COMM_SELF,MAT_INITIAL_MATRIX,&Br);
 57:         if (!ierrb) ierrb |= MatConvert(Br,MATSEQDENSE,MAT_INITIAL_MATRIX,&Bdense);
 58:         ierrb |= MatDestroy(&Br);
 59:         PetscCall(PetscPopErrorHandler());
 60:       } else ierrb = 1;
 61:     } else ierrb = 0;
 62:     denseok = PetscNot(ierra || ierrb);
 63:   }

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

 80:   if (denseok) {
 81:     PetscCall(STGetShift(eps->st,&shift));
 82:     if (shift != 0.0) {
 83:       if (nmat>1) PetscCall(MatAXPY(Adense,-shift,Bdense,SAME_NONZERO_PATTERN));
 84:       else PetscCall(MatShift(Adense,-shift));
 85:     }
 86:     /* use dummy pc and ksp to avoid problems when B is not positive definite */
 87:     PetscCall(STGetKSP(eps->st,&ksp));
 88:     PetscCall(KSPSetType(ksp,KSPPREONLY));
 89:     PetscCall(KSPGetPC(ksp,&pc));
 90:     PetscCall(PCSetType(pc,PCNONE));
 91:   } else {
 92:     PetscCall(PetscInfo(eps,"Using slow explicit operator\n"));
 93:     PetscCall(STGetOperator(eps->st,&shell));
 94:     PetscCall(MatComputeOperator(shell,MATDENSE,&OP));
 95:     PetscCall(STRestoreOperator(eps->st,&shell));
 96:     PetscCall(MatDestroy(&Adense));
 97:     PetscCall(MatCreateRedundantMatrix(OP,0,PETSC_COMM_SELF,MAT_INITIAL_MATRIX,&Adense));
 98:     PetscCall(MatDestroy(&OP));
 99:   }

101:   /* fill DS matrices */
102:   PetscCall(DSGetMat(eps->ds,DS_MAT_A,&Ads));
103:   PetscCall(MatCopy(Adense,Ads,SAME_NONZERO_PATTERN));
104:   PetscCall(DSRestoreMat(eps->ds,DS_MAT_A,&Ads));
105:   if (denseok && eps->isgeneralized) {
106:     PetscCall(DSGetMat(eps->ds,DS_MAT_B,&Bds));
107:     PetscCall(MatCopy(Bdense,Bds,SAME_NONZERO_PATTERN));
108:     PetscCall(DSRestoreMat(eps->ds,DS_MAT_B,&Bds));
109:   }
110:   PetscCall(DSSetState(eps->ds,DS_STATE_RAW));
111:   PetscCall(MatDestroy(&Adense));
112:   PetscCall(MatDestroy(&Bdense));
113:   PetscFunctionReturn(PETSC_SUCCESS);
114: }

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

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

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

140:   /* left eigenvectors */
141:   if (eps->twosided) {
142:     PetscCall(DSVectors(eps->ds,DS_MAT_Y,NULL,NULL));
143:     PetscCall(DSGetArray(eps->ds,DS_MAT_Y,&pY));
144:     for (i=0;i<eps->ncv;i++) {
145:       PetscCall(BVGetColumn(eps->W,i,&w));
146:       PetscCall(VecGetOwnershipRange(w,&low,&high));
147:       PetscCall(VecGetArray(w,&array));
148:       PetscCall(PetscArraycpy(array,pY+i*n+low,high-low));
149:       PetscCall(VecRestoreArray(w,&array));
150:       PetscCall(BVRestoreColumn(eps->W,i,&w));
151:     }
152:     PetscCall(DSRestoreArray(eps->ds,DS_MAT_Y,&pY));
153:   }

155:   eps->nconv  = eps->ncv;
156:   eps->its    = 1;
157:   eps->reason = EPS_CONVERGED_TOL;
158:   PetscFunctionReturn(PETSC_SUCCESS);
159: }

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

167:   eps->ops->solve          = EPSSolve_LAPACK;
168:   eps->ops->setup          = EPSSetUp_LAPACK;
169:   eps->ops->setupsort      = EPSSetUpSort_Default;
170:   eps->ops->backtransform  = EPSBackTransform_Default;
171:   PetscFunctionReturn(PETSC_SUCCESS);
172: }