Actual source code: trlan.c

  2: /*                       
  3:        This file implements a wrapper to the TRLAN package
  4: */
 5:  #include src/eps/impls/trlan/trlanp.h

  7: /* Nasty global variable to access EPS data from TRLan_ */
  8: static EPS globaleps;

 12: static int EPSSetUp_TRLAN(EPS eps)
 13: {
 14:   int        ierr, n;
 15:   EPS_TRLAN *tr = (EPS_TRLAN *)eps->data;

 18: #if defined(PETSC_USE_COMPLEX)
 19:   SETERRQ(PETSC_ERR_SUP,"Requested method is not available for complex problems");
 20: #endif
 21:   if (!eps->ishermitian)
 22:     SETERRQ(PETSC_ERR_SUP,"Requested method is only available for Hermitian problems");

 24:   if (eps->isgeneralized)
 25:     SETERRQ(PETSC_ERR_SUP,"Requested method is not available for generalized problems");

 27:   tr->restart = 0;
 28:   VecGetLocalSize(eps->vec_initial,&n);
 29:   tr->maxlan = eps->nev+PetscMin(eps->nev,6);
 30:   if (tr->maxlan+1-eps->ncv<=0) tr->lwork = tr->maxlan*(tr->maxlan+10);
 31:   else tr->lwork = n*(tr->maxlan+1-eps->ncv) + tr->maxlan*(tr->maxlan+10);
 32:   PetscMalloc(tr->lwork*sizeof(PetscReal),&tr->work);

 34:   return(0);
 35: }

 39: static int EPSSetDefaults_TRLAN(EPS eps)
 40: {
 41:   int         ierr, N;

 44:   VecGetSize(eps->vec_initial,&N);
 45:   if (eps->ncv) {
 46:     if (eps->ncv<eps->nev) SETERRQ(1,"The value of ncv must be at least nev");
 47:   }
 48:   else eps->ncv = eps->nev;
 49:   if (!eps->max_it) eps->max_it = PetscMax(100,N);
 50:   if (!eps->tol) eps->tol = 1.e-7;
 51:   return(0);
 52: }

 56: static int MatMult_TRLAN(int *n,int *m,PetscReal *xin,int *ldx,PetscReal *yout,int *ldy)
 57: {
 58:   Vec    x,y;
 59:   int    i,ierr;

 62:   VecCreateMPIWithArray(globaleps->comm,*n,PETSC_DECIDE,PETSC_NULL,&x);
 63:   VecCreateMPIWithArray(globaleps->comm,*n,PETSC_DECIDE,PETSC_NULL,&y);
 64:   for (i=0;i<*m;i++) {
 65:     VecPlaceArray(x,(PetscScalar*)xin+i*(*ldx));
 66:     VecPlaceArray(y,(PetscScalar*)yout+i*(*ldy));
 67:     STApply(globaleps->OP,x,y);
 68:   }
 69:   return(0);
 70: }

 74: static int  EPSSolve_TRLAN(EPS eps)
 75: {
 76:   int         ipar[32], i, n, lohi, stat, ierr;
 77:   EPS_TRLAN   *tr = (EPS_TRLAN *)eps->data;
 78:   PetscScalar *pV;
 79: 

 82:   VecGetLocalSize(eps->vec_initial,&n);
 83: 
 84:   if (eps->which==EPS_LARGEST_REAL) lohi = 1;
 85:   else if (eps->which==EPS_SMALLEST_REAL) lohi = -1;
 86:   else SETERRQ(1,"Wrong value of eps->which");

 88:   globaleps = eps;

 90:   ipar[0]  = 0;            /* stat: error flag */
 91:   ipar[1]  = lohi;         /* smallest (lohi<0) or largest eigenvalues (lohi>0) */
 92:   ipar[2]  = eps->nev;     /* 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:   ipar[6]  = eps->max_it;  /* maximum number of MATVECs */
 97:   ipar[7]  = MPI_Comm_c2f(eps->comm);    /* communicator */
 98:   ipar[8]  = 0;            /* verboseness */
 99:   ipar[9]  = 99;           /* Fortran IO unit number used to write log messages */
100:   ipar[10] = 1;            /* use supplied starting vector */
101:   ipar[11] = 0;            /* checkpointing flag */
102:   ipar[12] = 98;           /* Fortran IO unit number used to write checkpoint files */
103:   ipar[13] = 0;            /* number of flops per matvec per PE (not used) */
104:   tr->work[0] = eps->tol;  /* relative tolerance on residual norms */

106:   for (i=0;i<eps->ncv;i++) eps->eigr[i]=0.0;
107:   VecCopy(eps->vec_initial,eps->V[0]);
108:   VecGetArray(eps->V[0],&pV);

110:   TRLan_ ( MatMult_TRLAN, ipar, &n, &eps->ncv, eps->eigr, pV, &n, tr->work, &tr->lwork );

112:   VecRestoreArray( eps->V[0], &pV );

114:   stat        = ipar[0];
115:   eps->nconv  = ipar[3];
116:   eps->its    = ipar[25];
117:   eps->reason = EPS_CONVERGED_TOL;
118:   for (i=0;i<eps->nconv;i++) eps->eigi[i]=0.0;
119: 
120:   if (stat!=0) { SETERRQ1(PETSC_ERR_LIB,"Error in TRLAN (code=%d)",stat);}

122:   return(0);
123: }

127: int EPSDestroy_TRLAN(EPS eps)
128: {
129:   EPS_TRLAN *tr = (EPS_TRLAN *)eps->data;
130:   int         ierr;

134:   if (tr->work)  { PetscFree(tr->work); }
135:   if (eps->data) { PetscFree(eps->data); }
136:   return(0);
137: }

139: EXTERN_C_BEGIN
142: int EPSCreate_TRLAN(EPS eps)
143: {
144:   EPS_TRLAN *trlan;
145:   int        ierr;

148:   PetscNew(EPS_TRLAN,&trlan);
149:   PetscMemzero(trlan,sizeof(EPS_TRLAN));
150:   PetscLogObjectMemory(eps,sizeof(EPS_TRLAN));
151:   eps->data                      = (void *) trlan;
152:   eps->ops->setup                = EPSSetUp_TRLAN;
153:   eps->ops->setdefaults          = EPSSetDefaults_TRLAN;
154:   eps->ops->solve                = EPSSolve_TRLAN;
155:   eps->ops->destroy              = EPSDestroy_TRLAN;
156:   eps->ops->view                 = 0;
157:   eps->ops->backtransform        = EPSBackTransform_Default;
158:   eps->which = EPS_LARGEST_REAL;
159:   return(0);
160: }
161: EXTERN_C_END