Actual source code: trlan.c
slepc-3.21.1 2024-04-26
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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: static PetscErrorCode EPSSetUp_TRLAN(EPS eps)
     24: {
     25:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;

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

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

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

     48:   PetscCall(EPSAllocateSolution(eps,0));
     49:   PetscFunctionReturn(PETSC_SUCCESS);
     50: }

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

     58:   PetscFunctionBegin;
     59:   for (i=0;i<*m;i++) {
     60:     PetscCall(VecPlaceArray(x,(PetscScalar*)xin+i*(*ldx)));
     61:     PetscCall(VecPlaceArray(y,(PetscScalar*)yout+i*(*ldy)));
     62:     PetscCall(STApply(eps->st,x,y));
     63:     PetscCall(BVOrthogonalizeVec(eps->V,y,NULL,NULL,NULL));
     64:     PetscCall(VecResetArray(x));
     65:     PetscCall(VecResetArray(y));
     66:   }
     67:   PetscFunctionReturn(PETSC_SUCCESS);
     68: }

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

     82:   PetscFunctionBegin;
     83:   PetscCall(PetscBLASIntCast(eps->ncv,&ncv));
     84:   PetscCall(PetscBLASIntCast(eps->nloc,&n));

     86:   PetscCheck(eps->which==EPS_LARGEST_REAL || eps->which==EPS_TARGET_REAL || eps->which==EPS_SMALLEST_REAL,PetscObjectComm((PetscObject)eps),PETSC_ERR_USER_INPUT,"Wrong value of eps->which");
     87:   lohi = (eps->which==EPS_SMALLEST_REAL)? -1: 1;

     89:   globaldata.eps = eps;
     90:   PetscCall(STGetMatrix(eps->st,0,&A));
     91:   PetscCall(MatCreateVecsEmpty(A,&globaldata.x,&globaldata.y));

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

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

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

    120:   PetscCall(VecRestoreArray(v0,&pV));
    121:   PetscCall(BVRestoreColumn(eps->V,0,&v0));

    123:   stat        = ipar[0];
    124:   eps->nconv  = ipar[3];
    125:   eps->its    = ipar[25];
    126:   eps->reason = EPS_CONVERGED_TOL;

    128:   PetscCall(VecDestroy(&globaldata.x));
    129:   PetscCall(VecDestroy(&globaldata.y));
    130:   PetscCheck(stat==0,PetscObjectComm((PetscObject)eps),PETSC_ERR_LIB,"Error in TRLAN (code=%" PetscBLASInt_FMT ")",stat);
    131:   PetscFunctionReturn(PETSC_SUCCESS);
    132: }

    134: static PetscErrorCode EPSReset_TRLAN(EPS eps)
    135: {
    136:   EPS_TRLAN      *tr = (EPS_TRLAN*)eps->data;

    138:   PetscFunctionBegin;
    139:   PetscCall(PetscFree(tr->work));
    140:   PetscFunctionReturn(PETSC_SUCCESS);
    141: }

    143: static PetscErrorCode EPSDestroy_TRLAN(EPS eps)
    144: {
    145:   PetscFunctionBegin;
    146:   PetscCall(PetscFree(eps->data));
    147:   PetscFunctionReturn(PETSC_SUCCESS);
    148: }

    150: SLEPC_EXTERN PetscErrorCode EPSCreate_TRLAN(EPS eps)
    151: {
    152:   EPS_TRLAN      *ctx;

    154:   PetscFunctionBegin;
    155:   PetscCall(PetscNew(&ctx));
    156:   eps->data = (void*)ctx;

    158:   eps->ops->solve          = EPSSolve_TRLAN;
    159:   eps->ops->setup          = EPSSetUp_TRLAN;
    160:   eps->ops->setupsort      = EPSSetUpSort_Basic;
    161:   eps->ops->destroy        = EPSDestroy_TRLAN;
    162:   eps->ops->reset          = EPSReset_TRLAN;
    163:   eps->ops->backtransform  = EPSBackTransform_Default;
    164:   PetscFunctionReturn(PETSC_SUCCESS);
    165: }