Date: 2021-02-01T14:41:59+00:00

Actual source code: trlan.c
slepc-3.14.2 2021-02-01
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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: }