Actual source code: lapack.c

slepc-3.17.2 2022-08-09
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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;
 22:   PetscScalar    shift,*Ap,*Bp;
 23:   PetscInt       i,ld,nmat;
 24:   KSP            ksp;
 25:   PC             pc;
 26:   Vec            v;

 28:   eps->ncv = eps->n;
 29:   if (eps->mpd!=PETSC_DEFAULT) PetscInfo(eps,"Warning: parameter mpd ignored\n");
 30:   if (eps->max_it==PETSC_DEFAULT) eps->max_it = 1;
 31:   if (!eps->which) EPSSetWhichEigenpairs_Default(eps);
 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:   EPSAllocateSolution(eps,0);

 37:   /* attempt to get dense representations of A and B separately */
 38:   PetscObjectTypeCompare((PetscObject)eps->st,STSHIFT,&isshift);
 39:   if (isshift) {
 40:     STGetNumMatrices(eps->st,&nmat);
 41:     STGetMatrix(eps->st,0,&A);
 42:     MatHasOperation(A,MATOP_CREATE_SUBMATRICES,&flg);
 43:     if (flg) {
 44:       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:       PetscPopErrorHandler();
 49:     } else ierra = 1;
 50:     if (nmat>1) {
 51:       STGetMatrix(eps->st,1,&B);
 52:       MatHasOperation(B,MATOP_CREATE_SUBMATRICES,&flg);
 53:       if (flg) {
 54:         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:         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) DSSetType(eps->ds,DSGHEP);
 69:         else DSSetType(eps->ds,DSGNHEP); /* TODO: should be DSGHIEP */
 70:       } else DSSetType(eps->ds,DSGNHEP);
 71:     } else {
 72:       if (eps->ishermitian) DSSetType(eps->ds,DSHEP);
 73:       else DSSetType(eps->ds,DSNHEP);
 74:     }
 75:   } else DSSetType(eps->ds,DSNHEP);
 76:   DSAllocate(eps->ds,eps->ncv);
 77:   DSGetLeadingDimension(eps->ds,&ld);
 78:   DSSetDimensions(eps->ds,eps->ncv,0,0);

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

101:   /* fill DS matrices */
102:   VecCreateSeqWithArray(PETSC_COMM_SELF,1,ld,NULL,&v);
103:   DSGetArray(eps->ds,DS_MAT_A,&Ap);
104:   for (i=0;i<ld;i++) {
105:     VecPlaceArray(v,Ap+i*ld);
106:     MatGetColumnVector(Adense,v,i);
107:     VecResetArray(v);
108:   }
109:   DSRestoreArray(eps->ds,DS_MAT_A,&Ap);
110:   if (denseok && eps->isgeneralized) {
111:     DSGetArray(eps->ds,DS_MAT_B,&Bp);
112:     for (i=0;i<ld;i++) {
113:       VecPlaceArray(v,Bp+i*ld);
114:       MatGetColumnVector(Bdense,v,i);
115:       VecResetArray(v);
116:     }
117:     DSRestoreArray(eps->ds,DS_MAT_B,&Bp);
118:   }
119:   VecDestroy(&v);
120:   DSSetState(eps->ds,DS_STATE_RAW);
121:   MatDestroy(&Adense);
122:   MatDestroy(&Bdense);
123:   PetscFunctionReturn(0);
124: }

126: PetscErrorCode EPSSolve_LAPACK(EPS eps)
127: {
128:   PetscInt       n=eps->n,i,low,high;
129:   PetscScalar    *array,*pX,*pY;
130:   Vec            v,w;

132:   DSSolve(eps->ds,eps->eigr,eps->eigi);
133:   DSSort(eps->ds,eps->eigr,eps->eigi,NULL,NULL,NULL);
134:   DSSynchronize(eps->ds,eps->eigr,eps->eigi);

136:   /* right eigenvectors */
137:   DSVectors(eps->ds,DS_MAT_X,NULL,NULL);
138:   DSGetArray(eps->ds,DS_MAT_X,&pX);
139:   for (i=0;i<eps->ncv;i++) {
140:     BVGetColumn(eps->V,i,&v);
141:     VecGetOwnershipRange(v,&low,&high);
142:     VecGetArray(v,&array);
143:     PetscArraycpy(array,pX+i*n+low,high-low);
144:     VecRestoreArray(v,&array);
145:     BVRestoreColumn(eps->V,i,&v);
146:   }
147:   DSRestoreArray(eps->ds,DS_MAT_X,&pX);

149:   /* left eigenvectors */
150:   if (eps->twosided) {
151:     DSVectors(eps->ds,DS_MAT_Y,NULL,NULL);
152:     DSGetArray(eps->ds,DS_MAT_Y,&pY);
153:     for (i=0;i<eps->ncv;i++) {
154:       BVGetColumn(eps->W,i,&w);
155:       VecGetOwnershipRange(w,&low,&high);
156:       VecGetArray(w,&array);
157:       PetscArraycpy(array,pY+i*n+low,high-low);
158:       VecRestoreArray(w,&array);
159:       BVRestoreColumn(eps->W,i,&w);
160:     }
161:     DSRestoreArray(eps->ds,DS_MAT_Y,&pY);
162:   }

164:   eps->nconv  = eps->ncv;
165:   eps->its    = 1;
166:   eps->reason = EPS_CONVERGED_TOL;
167:   PetscFunctionReturn(0);
168: }

170: SLEPC_EXTERN PetscErrorCode EPSCreate_LAPACK(EPS eps)
171: {
172:   eps->useds = PETSC_TRUE;
173:   eps->categ = EPS_CATEGORY_OTHER;

175:   eps->ops->solve          = EPSSolve_LAPACK;
176:   eps->ops->setup          = EPSSetUp_LAPACK;
177:   eps->ops->setupsort      = EPSSetUpSort_Default;
178:   eps->ops->backtransform  = EPSBackTransform_Default;
179:   PetscFunctionReturn(0);
180: }