Actual source code: lapack.c

slepc-3.18.0 2022-10-01
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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,Ads,Bds;
 22:   PetscScalar    shift;
 23:   PetscInt       nmat;
 24:   KSP            ksp;
 25:   PC             pc;

 27:   eps->ncv = eps->n;
 28:   if (eps->mpd!=PETSC_DEFAULT) PetscInfo(eps,"Warning: parameter mpd ignored\n");
 29:   if (eps->max_it==PETSC_DEFAULT) eps->max_it = 1;
 30:   if (!eps->which) EPSSetWhichEigenpairs_Default(eps);
 32:   EPSCheckUnsupported(eps,EPS_FEATURE_BALANCE | EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION | EPS_FEATURE_STOPPING);
 33:   EPSCheckIgnored(eps,EPS_FEATURE_EXTRACTION | EPS_FEATURE_CONVERGENCE);
 34:   EPSAllocateSolution(eps,0);

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

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

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

 99:   /* fill DS matrices */
100:   DSGetMat(eps->ds,DS_MAT_A,&Ads);
101:   MatCopy(Adense,Ads,SAME_NONZERO_PATTERN);
102:   DSRestoreMat(eps->ds,DS_MAT_A,&Ads);
103:   if (denseok && eps->isgeneralized) {
104:     DSGetMat(eps->ds,DS_MAT_B,&Bds);
105:     MatCopy(Bdense,Bds,SAME_NONZERO_PATTERN);
106:     DSRestoreMat(eps->ds,DS_MAT_B,&Bds);
107:   }
108:   DSSetState(eps->ds,DS_STATE_RAW);
109:   MatDestroy(&Adense);
110:   MatDestroy(&Bdense);
111:   return 0;
112: }

114: PetscErrorCode EPSSolve_LAPACK(EPS eps)
115: {
116:   PetscInt       n=eps->n,i,low,high;
117:   PetscScalar    *array,*pX,*pY;
118:   Vec            v,w;

120:   DSSolve(eps->ds,eps->eigr,eps->eigi);
121:   DSSort(eps->ds,eps->eigr,eps->eigi,NULL,NULL,NULL);
122:   DSSynchronize(eps->ds,eps->eigr,eps->eigi);

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

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

152:   eps->nconv  = eps->ncv;
153:   eps->its    = 1;
154:   eps->reason = EPS_CONVERGED_TOL;
155:   return 0;
156: }

158: SLEPC_EXTERN PetscErrorCode EPSCreate_LAPACK(EPS eps)
159: {
160:   eps->useds = PETSC_TRUE;
161:   eps->categ = EPS_CATEGORY_OTHER;

163:   eps->ops->solve          = EPSSolve_LAPACK;
164:   eps->ops->setup          = EPSSetUp_LAPACK;
165:   eps->ops->setupsort      = EPSSetUpSort_Default;
166:   eps->ops->backtransform  = EPSBackTransform_Default;
167:   return 0;
168: }