Date: 2022-11-02T11:46:51+00:00

Actual source code: trlan.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:    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: {
     25:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;

     27:   EPSCheckHermitian(eps);
     28:   EPSCheckStandard(eps);
     29:   PetscBLASIntCast(PetscMax(7,eps->nev+PetscMin(eps->nev,6)),&tr->maxlan);
     30:   if (eps->ncv!=PETSC_DEFAULT) {
     32:   } else eps->ncv = tr->maxlan;
     33:   if (eps->mpd!=PETSC_DEFAULT) PetscInfo(eps,"Warning: parameter mpd ignored\n");
     34:   if (eps->max_it==PETSC_DEFAULT) eps->max_it = PetscMax(1000,eps->n);

     36:   if (!eps->which) eps->which = EPS_LARGEST_REAL;
     38:   EPSCheckUnsupported(eps,EPS_FEATURE_ARBITRARY | EPS_FEATURE_REGION | EPS_FEATURE_CONVERGENCE | EPS_FEATURE_STOPPING);
     39:   EPSCheckIgnored(eps,EPS_FEATURE_BALANCE | EPS_FEATURE_EXTRACTION);

     41:   tr->restart = 0;
     42:   if (tr->maxlan+1-eps->ncv<=0) PetscBLASIntCast(tr->maxlan*(tr->maxlan+10),&tr->lwork);
     43:   else PetscBLASIntCast(eps->nloc*(tr->maxlan+1-eps->ncv) + tr->maxlan*(tr->maxlan+10),&tr->lwork);
     44:   if (tr->work) PetscFree(tr->work);
     45:   PetscMalloc1(tr->lwork,&tr->work);

     47:   EPSAllocateSolution(eps,0);
     48:   return 0;
     49: }

     51: static PetscBLASInt MatMult_TRLAN(PetscBLASInt *n,PetscBLASInt *m,PetscReal *xin,PetscBLASInt *ldx,PetscReal *yout,PetscBLASInt *ldy)
     52: {
     53:   Vec            x=globaldata.x,y=globaldata.y;
     54:   EPS            eps=globaldata.eps;
     55:   PetscBLASInt   i;

     57:   for (i=0;i<*m;i++) {
     58:     VecPlaceArray(x,(PetscScalar*)xin+i*(*ldx));
     59:     VecPlaceArray(y,(PetscScalar*)yout+i*(*ldy));
     60:     STApply(eps->st,x,y);
     61:     BVOrthogonalizeVec(eps->V,y,NULL,NULL,NULL);
     62:     VecResetArray(x);
     63:     VecResetArray(y);
     64:   }
     65:   return 0;
     66: }

     68: PetscErrorCode EPSSolve_TRLAN(EPS eps)
     69: {
     70:   PetscInt       i;
     71:   PetscBLASInt   ipar[32],n,lohi,stat,ncv;
     72:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;
     73:   PetscScalar    *pV;
     74:   Vec            v0;
     75:   Mat            A;
     76: #if !defined(PETSC_HAVE_MPIUNI)
     77:   MPI_Fint       fcomm;
     78: #endif

     80:   PetscBLASIntCast(eps->ncv,&ncv);
     81:   PetscBLASIntCast(eps->nloc,&n);

     84:   lohi = (eps->which==EPS_SMALLEST_REAL)? -1: 1;

     86:   globaldata.eps = eps;
     87:   STGetMatrix(eps->st,0,&A);
     88:   MatCreateVecsEmpty(A,&globaldata.x,&globaldata.y);

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

    109:   for (i=0;i<eps->ncv;i++) eps->eigr[i]=0.0;
    110:   EPSGetStartVector(eps,0,NULL);
    111:   BVSetActiveColumns(eps->V,0,0);  /* just for deflation space */
    112:   BVGetColumn(eps->V,0,&v0);
    113:   VecGetArray(v0,&pV);

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

    117:   VecRestoreArray(v0,&pV);
    118:   BVRestoreColumn(eps->V,0,&v0);

    120:   stat        = ipar[0];
    121:   eps->nconv  = ipar[3];
    122:   eps->its    = ipar[25];
    123:   eps->reason = EPS_CONVERGED_TOL;

    125:   VecDestroy(&globaldata.x);
    126:   VecDestroy(&globaldata.y);
    128:   return 0;
    129: }

    131: PetscErrorCode EPSReset_TRLAN(EPS eps)
    132: {
    133:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;

    135:   PetscFree(tr->work);
    136:   return 0;
    137: }

    139: PetscErrorCode EPSDestroy_TRLAN(EPS eps)
    140: {
    141:   PetscFree(eps->data);
    142:   return 0;
    143: }

    145: SLEPC_EXTERN PetscErrorCode EPSCreate_TRLAN(EPS eps)
    146: {
    147:   EPS_TRLAN      *ctx;

    149:   PetscNew(&ctx);
    150:   eps->data = (void*)ctx;

    152:   eps->ops->solve          = EPSSolve_TRLAN;
    153:   eps->ops->setup          = EPSSetUp_TRLAN;
    154:   eps->ops->setupsort      = EPSSetUpSort_Basic;
    155:   eps->ops->destroy        = EPSDestroy_TRLAN;
    156:   eps->ops->reset          = EPSReset_TRLAN;
    157:   eps->ops->backtransform  = EPSBackTransform_Default;
    158:   return 0;
    159: }