Actual source code: dvdinitv.c

slepc-3.18.1 2022-11-02
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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:    SLEPc eigensolver: "davidson"

 13:    Step: initialize subspace V
 14: */

 16: #include "davidson.h"

 18: typedef struct {
 19:   PetscInt k;                 /* desired initial subspace size */
 20:   PetscInt user;              /* number of user initial vectors */
 21:   void     *old_initV_data;   /* old initV data */
 22: } dvdInitV;

 24: static PetscErrorCode dvd_initV_classic_0(dvdDashboard *d)
 25: {
 26:   dvdInitV       *data = (dvdInitV*)d->initV_data;
 27:   PetscInt       i,user = PetscMin(data->user,d->eps->mpd), l,k;

 29:   BVGetActiveColumns(d->eps->V,&l,&k);
 30:   /* User vectors are added at the beginning, so no active column should be in V */
 31:   PetscAssert(data->user==0 || l==0,PETSC_COMM_SELF,PETSC_ERR_PLIB,"Consistency broken");
 32:   /* Generate a set of random initial vectors and orthonormalize them */
 33:   for (i=l+user;i<l+data->k && i<d->eps->ncv && i-l<d->eps->mpd;i++) BVSetRandomColumn(d->eps->V,i);
 34:   d->V_tra_s = 0; d->V_tra_e = 0;
 35:   d->V_new_s = 0; d->V_new_e = i-l;

 37:   /* After that the user vectors will be destroyed */
 38:   data->user = 0;
 39:   return 0;
 40: }

 42: static PetscErrorCode dvd_initV_krylov_0(dvdDashboard *d)
 43: {
 44:   dvdInitV       *data = (dvdInitV*)d->initV_data;
 45:   PetscInt       i,user = PetscMin(data->user,d->eps->mpd),l,k;
 46:   Vec            av,v1,v2;

 48:   BVGetActiveColumns(d->eps->V,&l,&k);
 49:   /* User vectors are added at the beginning, so no active column should be in V */
 50:   PetscAssert(data->user==0 || l==0,PETSC_COMM_SELF,PETSC_ERR_PLIB,"Consistency broken");

 52:   /* If needed, generate a random vector for starting the arnoldi method */
 53:   if (user == 0) {
 54:     BVSetRandomColumn(d->eps->V,l);
 55:     user = 1;
 56:   }

 58:   /* Perform k steps of Arnoldi with the operator K^{-1}*(t[1]*A-t[2]*B) */
 59:   dvd_orthV(d->eps->V,l,l+user);
 60:   for (i=l+user;i<l+data->k && i<d->eps->ncv && i-l<d->eps->mpd;i++) {
 61:     /* aux <- theta[1]A*in - theta[0]*B*in */
 62:     BVGetColumn(d->eps->V,i,&v1);
 63:     BVGetColumn(d->eps->V,i-user,&v2);
 64:     BVGetColumn(d->auxBV,0,&av);
 65:     if (d->B) {
 66:       MatMult(d->A,v2,v1);
 67:       MatMult(d->B,v2,av);
 68:       VecAXPBY(av,d->target[1],-d->target[0],v1);
 69:     } else {
 70:       MatMult(d->A,v2,av);
 71:       VecAXPBY(av,-d->target[0],d->target[1],v2);
 72:     }
 73:     d->improvex_precond(d,0,av,v1);
 74:     BVRestoreColumn(d->eps->V,i,&v1);
 75:     BVRestoreColumn(d->eps->V,i-user,&v2);
 76:     BVRestoreColumn(d->auxBV,0,&av);
 77:     dvd_orthV(d->eps->V,i,i+1);
 78:   }

 80:   d->V_tra_s = 0; d->V_tra_e = 0;
 81:   d->V_new_s = 0; d->V_new_e = i-l;

 83:   /* After that the user vectors will be destroyed */
 84:   data->user = 0;
 85:   return 0;
 86: }

 88: static PetscErrorCode dvd_initV_d(dvdDashboard *d)
 89: {
 90:   dvdInitV       *data = (dvdInitV*)d->initV_data;

 92:   /* Restore changes in dvdDashboard */
 93:   d->initV_data = data->old_initV_data;

 95:   /* Free local data */
 96:   PetscFree(data);
 97:   return 0;
 98: }

100: PetscErrorCode dvd_initV(dvdDashboard *d, dvdBlackboard *b, PetscInt k,PetscInt user, PetscBool krylov)
101: {
102:   dvdInitV       *data;

104:   /* Setting configuration constrains */
105:   b->max_size_V = PetscMax(b->max_size_V, k);

107:   /* Setup the step */
108:   if (b->state >= DVD_STATE_CONF) {
109:     PetscNew(&data);
110:     data->k = k;
111:     data->user = user;
112:     data->old_initV_data = d->initV_data;
113:     d->initV_data = data;
114:     if (krylov) d->initV = dvd_initV_krylov_0;
115:     else d->initV = dvd_initV_classic_0;
116:     EPSDavidsonFLAdd(&d->destroyList,dvd_initV_d);
117:   }
118:   return 0;
119: }

121: PetscErrorCode dvd_orthV(BV V,PetscInt V_new_s,PetscInt V_new_e)
122: {
123:   PetscInt       i;

125:   for (i=V_new_s;i<V_new_e;i++) BVOrthonormalizeColumn(V,i,PETSC_TRUE,NULL,NULL);
126:   return 0;
127: }