Actual source code: lapack.c

slepc-3.21.1 2024-04-26
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:   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: }