Actual source code: trlan.c

slepc-3.14.0 2020-09-30
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2020, 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 TRLAN package
 12: */

 14: #include <slepc/private/epsimpl.h>
 15: #include "trlan.h"

 17: /* Nasty global variable to access EPS data from TRLan_ */
 18: static struct {
 19:   EPS eps;
 20:   Vec x,y;
 21: } globaldata;

 23: PetscErrorCode EPSSetUp_TRLAN(EPS eps)
 24: {
 26:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;

 29:   EPSCheckHermitian(eps);
 30:   EPSCheckStandard(eps);
 31:   PetscBLASIntCast(PetscMax(7,eps->nev+PetscMin(eps->nev,6)),&tr->maxlan);
 32:   if (eps->ncv!=PETSC_DEFAULT) {
 33:     if (eps->ncv<eps->nev) SETERRQ(PetscObjectComm((PetscObject)eps),1,"The value of ncv must be at least nev");
 34:   } else eps->ncv = tr->maxlan;
 35:   if (eps->mpd!=PETSC_DEFAULT) { PetscInfo(eps,"Warning: parameter mpd ignored\n"); }
 36:   if (eps->max_it==PETSC_DEFAULT) eps->max_it = PetscMax(1000,eps->n);

 38:   if (!eps->which) eps->which = EPS_LARGEST_REAL;
 39:   if (eps->which!=EPS_SMALLEST_REAL && eps->which!=EPS_LARGEST_REAL && eps->which!=EPS_TARGET_REAL) SETERRQ(PetscObjectComm((PetscObject)eps),PETSC_ERR_SUP,"This solver supports only smallest, largest or target real eigenvalues");
 40:   EPSCheckUnsupported(eps,EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION | EPS_FEATURE_CONVERGENCE | EPS_FEATURE_STOPPING);
 41:   EPSCheckIgnored(eps,EPS_FEATURE_BALANCE | EPS_FEATURE_EXTRACTION);

 43:   tr->restart = 0;
 44:   if (tr->maxlan+1-eps->ncv<=0) {
 45:     PetscBLASIntCast(tr->maxlan*(tr->maxlan+10),&tr->lwork);
 46:   } else {
 47:     PetscBLASIntCast(eps->nloc*(tr->maxlan+1-eps->ncv) + tr->maxlan*(tr->maxlan+10),&tr->lwork);
 48:   }
 49:   if (tr->work) { PetscFree(tr->work); }
 50:   PetscMalloc1(tr->lwork,&tr->work);
 51:   PetscLogObjectMemory((PetscObject)eps,tr->lwork*sizeof(PetscReal));

 53:   EPSAllocateSolution(eps,0);
 54:   return(0);
 55: }

 57: static PetscBLASInt MatMult_TRLAN(PetscBLASInt *n,PetscBLASInt *m,PetscReal *xin,PetscBLASInt *ldx,PetscReal *yout,PetscBLASInt *ldy)
 58: {
 60:   Vec            x=globaldata.x,y=globaldata.y;
 61:   EPS            eps=globaldata.eps;
 62:   PetscBLASInt   i;

 65:   for (i=0;i<*m;i++) {
 66:     VecPlaceArray(x,(PetscScalar*)xin+i*(*ldx));
 67:     VecPlaceArray(y,(PetscScalar*)yout+i*(*ldy));
 68:     STApply(eps->st,x,y);
 69:     BVOrthogonalizeVec(eps->V,y,NULL,NULL,NULL);
 70:     VecResetArray(x);
 71:     VecResetArray(y);
 72:   }
 73:   return(0);
 74: }

 76: PetscErrorCode EPSSolve_TRLAN(EPS eps)
 77: {
 79:   PetscInt       i;
 80:   PetscBLASInt   ipar[32],n,lohi,stat,ncv;
 81:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;
 82:   PetscScalar    *pV;
 83:   Vec            v0;
 84:   Mat            A;
 85: #if !defined(PETSC_HAVE_MPIUNI)
 86:   MPI_Fint       fcomm;
 87: #endif

 90:   PetscBLASIntCast(eps->ncv,&ncv);
 91:   PetscBLASIntCast(eps->nloc,&n);

 93:   if (eps->which==EPS_LARGEST_REAL || eps->which==EPS_TARGET_REAL) lohi = 1;
 94:   else if (eps->which==EPS_SMALLEST_REAL) lohi = -1;
 95:   else SETERRQ(PetscObjectComm((PetscObject)eps),1,"Wrong value of eps->which");

 97:   globaldata.eps = eps;
 98:   STGetMatrix(eps->st,0,&A);
 99:   MatCreateVecsEmpty(A,&globaldata.x,&globaldata.y);

101:   ipar[0]  = 0;            /* stat: error flag */
102:   ipar[1]  = lohi;         /* smallest (lohi<0) or largest eigenvalues (lohi>0) */
103:   PetscBLASIntCast(eps->nev,&ipar[2]); /* number of desired eigenpairs */
104:   ipar[3]  = 0;            /* number of eigenpairs already converged */
105:   ipar[4]  = tr->maxlan;   /* maximum Lanczos basis size */
106:   ipar[5]  = tr->restart;  /* restarting scheme */
107:   PetscBLASIntCast(eps->max_it,&ipar[6]); /* maximum number of MATVECs */
108: #if !defined(PETSC_HAVE_MPIUNI)
109:   fcomm    = MPI_Comm_c2f(PetscObjectComm((PetscObject)eps));
110:   ipar[7]  = fcomm;
111: #endif
112:   ipar[8]  = 0;            /* verboseness */
113:   ipar[9]  = 99;           /* Fortran IO unit number used to write log messages */
114:   ipar[10] = 1;            /* use supplied starting vector */
115:   ipar[11] = 0;            /* checkpointing flag */
116:   ipar[12] = 98;           /* Fortran IO unit number used to write checkpoint files */
117:   ipar[13] = 0;            /* number of flops per matvec per PE (not used) */
118:   tr->work[0] = eps->tol;  /* relative tolerance on residual norms */

120:   for (i=0;i<eps->ncv;i++) eps->eigr[i]=0.0;
121:   EPSGetStartVector(eps,0,NULL);
122:   BVSetActiveColumns(eps->V,0,0);  /* just for deflation space */
123:   BVGetColumn(eps->V,0,&v0);
124:   VecGetArray(v0,&pV);

126:   PetscStackCall("TRLan",TRLan_(MatMult_TRLAN,ipar,&n,&ncv,eps->eigr,pV,&n,tr->work,&tr->lwork));

128:   VecRestoreArray(v0,&pV);
129:   BVRestoreColumn(eps->V,0,&v0);

131:   stat        = ipar[0];
132:   eps->nconv  = ipar[3];
133:   eps->its    = ipar[25];
134:   eps->reason = EPS_CONVERGED_TOL;

136:   VecDestroy(&globaldata.x);
137:   VecDestroy(&globaldata.y);
138:   if (stat!=0) SETERRQ1(PetscObjectComm((PetscObject)eps),PETSC_ERR_LIB,"Error in TRLAN (code=%d)",stat);
139:   return(0);
140: }

142: PetscErrorCode EPSReset_TRLAN(EPS eps)
143: {
145:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;

148:   PetscFree(tr->work);
149:   return(0);
150: }

152: PetscErrorCode EPSDestroy_TRLAN(EPS eps)
153: {

157:   PetscFree(eps->data);
158:   return(0);
159: }

161: SLEPC_EXTERN PetscErrorCode EPSCreate_TRLAN(EPS eps)
162: {
163:   EPS_TRLAN      *ctx;

167:   PetscNewLog(eps,&ctx);
168:   eps->data = (void*)ctx;

170:   eps->ops->solve          = EPSSolve_TRLAN;
171:   eps->ops->setup          = EPSSetUp_TRLAN;
172:   eps->ops->setupsort      = EPSSetUpSort_Basic;
173:   eps->ops->destroy        = EPSDestroy_TRLAN;
174:   eps->ops->reset          = EPSReset_TRLAN;
175:   eps->ops->backtransform  = EPSBackTransform_Default;
176:   return(0);
177: }