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/*

     This file contains some simple default routines for common QEP operations.  

   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

   SLEPc - Scalable Library for Eigenvalue Problem Computations

   Copyright (c) 2002-2009, Universidad Politecnica de Valencia, Spain

   This file is part of SLEPc.

   SLEPc is free software: you can redistribute it and/or modify it under  the

   terms of version 3 of the GNU Lesser General Public License as published by

   the Free Software Foundation.

   SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY

   WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS

   FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for

   more details.

   You  should have received a copy of the GNU Lesser General  Public  License

   along with SLEPc. If not, see <http://www.gnu.org/licenses/>.

   - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

*/

#include "private/qepimpl.h"   /*I "slepcqep.h" I*/

#include "private/slepcimpl.h"

#include "slepcblaslapack.h"

#undef __FUNCT__  

#define __FUNCT__ "QEPDestroy_Default"

PetscErrorCode QEPDestroy_Default(QEP qep)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(qep,QEP_COOKIE,1);

  ierr = PetscFree(qep->data);CHKERRQ(ierr);

  /* free work vectors */

  ierr = QEPDefaultFreeWork(qep);CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "QEPDefaultGetWork"

/*

  QEPDefaultGetWork - Gets a number of work vectors.

 */

PetscErrorCode QEPDefaultGetWork(QEP qep, PetscInt nw)

{

  PetscErrorCode ierr;

  PetscInt       i;

  PetscFunctionBegin;

  if (qep->nwork != nw) {

    if (qep->nwork > 0) {

      ierr = VecDestroyVecs(qep->work,qep->nwork); CHKERRQ(ierr);

    }

    qep->nwork = nw;

    ierr = PetscMalloc(nw*sizeof(Vec),&qep->work);CHKERRQ(ierr);

    for (i=0;i<nw;i++) {

      ierr = MatGetVecs(qep->M,PETSC_NULL,qep->work+i); CHKERRQ(ierr);

    }

    ierr = PetscLogObjectParents(qep,nw,qep->work);

  }

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "QEPDefaultFreeWork"

/*

  QEPDefaultFreeWork - Free work vectors.

 */

PetscErrorCode QEPDefaultFreeWork(QEP qep)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(qep,QEP_COOKIE,1);

  if (qep->work)  {

    ierr = VecDestroyVecs(qep->work,qep->nwork);CHKERRQ(ierr);

  }

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "QEPDefaultConverged"

/*

  QEPDefaultConverged - Checks convergence relative to the eigenvalue.

*/

PetscErrorCode QEPDefaultConverged(QEP qep,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)

{

  PetscReal w;

  PetscFunctionBegin;

  w = SlepcAbsEigenvalue(eigr,eigi);

  *errest = res;

  if (w > res) *errest = res / w;

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "QEPAbsoluteConverged"

/*

  QEPAbsoluteConverged - Checks convergence absolutely.

*/

PetscErrorCode QEPAbsoluteConverged(QEP qep,PetscScalar eigr,PetscScalar eigi,PetscReal res,PetscReal *errest,void *ctx)

{

  PetscFunctionBegin;

  *errest = res;

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "QEPComputeVectors_Schur"

PetscErrorCode QEPComputeVectors_Schur(QEP qep)

{

#if defined(SLEPC_MISSING_LAPACK_TREVC)

  SETERRQ(PETSC_ERR_SUP,"TREVC - Lapack routine is unavailable.");

#else

  PetscErrorCode ierr;

  PetscInt       i;

  PetscBLASInt   ncv,nconv,mout,info,one = 1;

  PetscScalar    *Z,*work,tmp;

#if defined(PETSC_USE_COMPLEX)

  PetscReal      *rwork;

#else 

  PetscReal      normi;

#endif

  PetscReal      norm;

  PetscFunctionBegin;

  ncv = PetscBLASIntCast(qep->ncv);

  nconv = PetscBLASIntCast(qep->nconv);

  ierr = PetscMalloc(nconv*nconv*sizeof(PetscScalar),&Z);CHKERRQ(ierr);

  ierr = PetscMalloc(3*nconv*sizeof(PetscScalar),&work);CHKERRQ(ierr);

#if defined(PETSC_USE_COMPLEX)

  ierr = PetscMalloc(nconv*sizeof(PetscReal),&rwork);CHKERRQ(ierr);

#endif

  /* right eigenvectors */

#if !defined(PETSC_USE_COMPLEX)

  LAPACKtrevc_("R","A",PETSC_NULL,&nconv,qep->T,&ncv,PETSC_NULL,&nconv,Z,&nconv,&nconv,&mout,work,&info);

#else

  LAPACKtrevc_("R","A",PETSC_NULL,&nconv,qep->T,&ncv,PETSC_NULL,&nconv,Z,&nconv,&nconv,&mout,work,rwork,&info);

#endif

  if (info) SETERRQ1(PETSC_ERR_LIB,"Error in Lapack xTREVC %i",info);

  /* normalize eigenvectors */

  for (i=0;i<qep->nconv;i++) {

#if !defined(PETSC_USE_COMPLEX)

    if (qep->eigi[i] != 0.0) {

      norm = BLASnrm2_(&nconv,Z+i*nconv,&one);

      normi = BLASnrm2_(&nconv,Z+(i+1)*nconv,&one);

      tmp = 1.0 / SlepcAbsEigenvalue(norm,normi);

      BLASscal_(&nconv,&tmp,Z+i*nconv,&one);

      BLASscal_(&nconv,&tmp,Z+(i+1)*nconv,&one);

      i++;    

    } else

#endif

    {

      norm = BLASnrm2_(&nconv,Z+i*nconv,&one);

      tmp = 1.0 / norm;

      BLASscal_(&nconv,&tmp,Z+i*nconv,&one);

    }

  }

  /* AV = V * Z */

  ierr = SlepcUpdateVectors(qep->nconv,qep->V,0,qep->nconv,Z,qep->nconv,PETSC_FALSE);CHKERRQ(ierr);

  ierr = PetscFree(Z);CHKERRQ(ierr);

  ierr = PetscFree(work);CHKERRQ(ierr);

#if defined(PETSC_USE_COMPLEX)

  ierr = PetscFree(rwork);CHKERRQ(ierr);

#endif

   PetscFunctionReturn(0);

#endif 

}

#undef __FUNCT__  

#define __FUNCT__ "QEPKrylovConvergence"

/*

   QEPKrylovConvergence - This is the analogue to EPSKrylovConvergence, but

   for quadratic Krylov methods.

   Differences:

   - Always non-symmetric

   - Does not check for STSHIFT

   - No correction factor

   - No support for true residual

*/

PetscErrorCode QEPKrylovConvergence(QEP qep,PetscInt kini,PetscInt nits,PetscScalar *S,PetscInt lds,PetscScalar *Q,PetscInt nv,PetscReal beta,PetscInt *kout,PetscScalar *work)

{

  PetscErrorCode ierr;

  PetscInt       k,marker;

  PetscScalar    re,im,*Z,*work2;

  PetscReal      resnorm;

  PetscTruth     iscomplex;

  PetscFunctionBegin;

  Z = work; work2 = work+2*nv;

  marker = -1;

  for (k=kini;k<kini+nits;k++) {

    /* eigenvalue */

    re = qep->eigr[k];

    im = qep->eigi[k];

    iscomplex = PETSC_FALSE;

    if (k<nv-1 && S[k+1+k*lds] != 0.0) iscomplex = PETSC_TRUE;

    /* residual norm */

    ierr = DenseSelectedEvec(S,lds,Q,Z,k,iscomplex,nv,work2);CHKERRQ(ierr);

    if (iscomplex) resnorm = beta*SlepcAbsEigenvalue(Z[nv-1],Z[2*nv-1]);

    else resnorm = beta*PetscAbsScalar(Z[nv-1]);

    /* error estimate */

    ierr = (*qep->conv_func)(qep,re,im,resnorm,&qep->errest[k],qep->conv_ctx);CHKERRQ(ierr);

    if (marker==-1 && qep->errest[k] >= qep->tol) marker = k;

    if (iscomplex) { qep->errest[k+1] = qep->errest[k]; k++; }

    if (marker!=-1 && !qep->trackall) break;

  }

  if (marker!=-1) k = marker;

  *kout = k;

  PetscFunctionReturn(0);

}