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/*

  SLEPc eigensolver: "gd"

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

   SLEPc - Scalable Library for Eigenvalue Problem Computations

   Copyright (c) 2002-2011, Universitat 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/epsimpl.h"                /*I "slepceps.h" I*/

#include <../src/eps/impls/davidson/common/davidson.h>

PetscErrorCode EPSSetUp_GD(EPS eps);

PetscErrorCode EPSDestroy_GD(EPS eps);

EXTERN_C_BEGIN

#undef __FUNCT__  

#define __FUNCT__ "EPSSetFromOptions_GD"

PetscErrorCode EPSSetFromOptions_GD(EPS eps)

{

  PetscErrorCode ierr;

  PetscBool      flg,op;

  PetscInt       opi,opi0;

  KSP            ksp;

  PetscFunctionBegin;

  ierr = PetscOptionsHead("EPS Generalized Davidson (GD) Options");CHKERRQ(ierr);

  ierr = EPSGDGetKrylovStart(eps,&op);CHKERRQ(ierr);

  ierr = PetscOptionsBool("-eps_gd_krylov_start","Start the searching subspace with a krylov basis","EPSGDSetKrylovStart",op,&op,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetKrylovStart(eps,op);CHKERRQ(ierr); }

  ierr = EPSGDGetBOrth(eps,&op);CHKERRQ(ierr);

  ierr = PetscOptionsBool("-eps_gd_borth","B-orthogonalize the searching subspace basis","EPSGDSetBOrth",op,&op,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetBOrth(eps,op);CHKERRQ(ierr); }

  ierr = EPSGDGetBlockSize(eps,&opi);CHKERRQ(ierr);

  ierr = PetscOptionsInt("-eps_gd_blocksize","Number vectors add to the searching subspace","EPSGDSetBlockSize",opi,&opi,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetBlockSize(eps,opi);CHKERRQ(ierr); }

  ierr = EPSGDGetRestart(eps,&opi,&opi0);CHKERRQ(ierr);

  ierr = PetscOptionsInt("-eps_gd_minv","Set the size of the searching subspace after restarting","EPSGDSetRestart",opi,&opi,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetRestart(eps,opi,opi0);CHKERRQ(ierr); }

  ierr = PetscOptionsInt("-eps_gd_plusk","Set the number of saved eigenvectors from the previous iteration when restarting","EPSGDSetRestart",opi0,&opi0,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetRestart(eps,opi,opi0);CHKERRQ(ierr); }

  ierr = EPSGDGetInitialSize(eps,&opi);CHKERRQ(ierr);

  ierr = PetscOptionsInt("-eps_gd_initial_size","Set the initial size of the searching subspace","EPSGDSetInitialSize",opi,&opi,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetInitialSize(eps,opi);CHKERRQ(ierr); }

  ierr = EPSGDGetWindowSizes(eps,&opi,&opi0);CHKERRQ(ierr);

  ierr = PetscOptionsInt("-eps_gd_pwindow","(Experimental!) Set the number of converged vectors in the projector","EPSGDSetWindowSizes",opi,&opi,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetWindowSizes(eps,opi,opi0);CHKERRQ(ierr); }

  ierr = PetscOptionsInt("-eps_gd_qwindow","(Experimental!) Set the number of converged vectors in the projected problem","EPSGDSetWindowSizes",opi0,&opi0,&flg);CHKERRQ(ierr);

  if(flg) { ierr = EPSGDSetWindowSizes(eps,opi,opi0);CHKERRQ(ierr); }

  ierr = PetscOptionsTail();CHKERRQ(ierr);

  /* Set STPrecond as the default ST */

  if (!((PetscObject)eps->OP)->type_name) {

    ierr = STSetType(eps->OP,STPRECOND);CHKERRQ(ierr);

  }

  ierr = STPrecondSetKSPHasMat(eps->OP,PETSC_FALSE);CHKERRQ(ierr);

  /* Set the default options of the KSP */

  ierr = STGetKSP(eps->OP,&ksp);CHKERRQ(ierr);

  if (!((PetscObject)ksp)->type_name) {

    ierr = KSPSetType(ksp,KSPPREONLY);CHKERRQ(ierr);

  }

  PetscFunctionReturn(0);

}  

EXTERN_C_END

#undef __FUNCT__  

#define __FUNCT__ "EPSSetUp_GD"

PetscErrorCode EPSSetUp_GD(EPS eps)

{

  PetscErrorCode ierr;

  PetscBool      t;

  KSP            ksp;

  PetscFunctionBegin;

  /* Setup common for all davidson solvers */

  ierr = EPSSetUp_Davidson(eps);CHKERRQ(ierr);

  /* Set KSPPREONLY as default */

  ierr = STGetKSP(eps->OP,&ksp);CHKERRQ(ierr);

  if (!((PetscObject)ksp)->type_name) {

    ierr = KSPSetType(ksp,KSPPREONLY);CHKERRQ(ierr);

  }

  /* Check some constraints */

  ierr = PetscTypeCompare((PetscObject)ksp,KSPPREONLY,&t);CHKERRQ(ierr);

  if (!t) SETERRQ(((PetscObject)eps)->comm,PETSC_ERR_SUP,"EPSGD only works with KSPPREONLY");

  PetscFunctionReturn(0);

}

EXTERN_C_BEGIN

#undef __FUNCT__  

#define __FUNCT__ "EPSCreate_GD"

PetscErrorCode EPSCreate_GD(EPS eps)

{

  PetscErrorCode  ierr;

  PetscFunctionBegin;

  /* Load the Davidson solver */

  ierr = EPSCreate_Davidson(eps);CHKERRQ(ierr);

  /* Overload the GD properties */

  eps->ops->setfromoptions       = EPSSetFromOptions_GD;

  eps->ops->setup                = EPSSetUp_GD;

  eps->ops->destroy              = EPSDestroy_GD;

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetKrylovStart_C","EPSDavidsonSetKrylovStart_Davidson",EPSDavidsonSetKrylovStart_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetKrylovStart_C","EPSDavidsonGetKrylovStart_Davidson",EPSDavidsonGetKrylovStart_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetBOrth_C","EPSDavidsonSetBOrth_Davidson",EPSDavidsonSetBOrth_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetBOrth_C","EPSDavidsonGetBOrth_Davidson",EPSDavidsonGetBOrth_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetBlockSize_C","EPSDavidsonSetBlockSize_Davidson",EPSDavidsonSetBlockSize_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetBlockSize_C","EPSDavidsonGetBlockSize_Davidson",EPSDavidsonGetBlockSize_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetRestart_C","EPSDavidsonSetRestart_Davidson",EPSDavidsonSetRestart_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetRestart_C","EPSDavidsonGetRestart_Davidson",EPSDavidsonGetRestart_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetInitialSize_C","EPSDavidsonSetInitialSize_Davidson",EPSDavidsonSetInitialSize_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetInitialSize_C","EPSDavidsonGetInitialSize_Davidson",EPSDavidsonGetInitialSize_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetWindowSizes_C","EPSDavidsonSetWindowSizes_Davidson",EPSDavidsonSetWindowSizes_Davidson);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetWindowSizes_C","EPSDavidsonGetWindowSizes_Davidson",EPSDavidsonGetWindowSizes_Davidson);CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

EXTERN_C_END

#undef __FUNCT__  

#define __FUNCT__ "EPSDestroy_GD"

PetscErrorCode EPSDestroy_GD(EPS eps)

{

  PetscErrorCode  ierr;

  PetscFunctionBegin;

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

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetKrylovStart_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetKrylovStart_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetBOrth_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetBOrth_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetBlockSize_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetBlockSize_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetRestart_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetRestart_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetInitialSize_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetInitialSize_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDSetWindowSizes_C","",PETSC_NULL);CHKERRQ(ierr);

  ierr = PetscObjectComposeFunctionDynamic((PetscObject)eps,"EPSGDGetWindowSizes_C","",PETSC_NULL);CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDSetKrylovStart"

/*@

   EPSGDSetKrylovStart - Activates or deactivates starting the searching

   subspace with a Krylov basis.

   Logically Collective on EPS

   Input Parameters:

+  eps - the eigenproblem solver context

-  krylovstart - boolean flag

   Options Database Key:

.  -eps_gd_krylov_start - Activates starting the searching subspace with a

    Krylov basis

   Level: advanced

.seealso: EPSGDGetKrylovStart()

@*/

PetscErrorCode EPSGDSetKrylovStart(EPS eps,PetscBool krylovstart)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidLogicalCollectiveBool(eps,krylovstart,2);

  ierr = PetscTryMethod(eps,"EPSGDSetKrylovStart_C",(EPS,PetscBool),(eps,krylovstart));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDGetKrylovStart"

/*@

   EPSGDGetKrylovStart - Returns a flag indicating if the search subspace is started with a

   Krylov basis.

   Not Collective

   Input Parameter:

.  eps - the eigenproblem solver context

   Output Parameters:

.  krylovstart - boolean flag indicating if the search subspace is started

   with a Krylov basis

   Level: advanced

.seealso: EPSGDGetKrylovStart()

@*/

PetscErrorCode EPSGDGetKrylovStart(EPS eps,PetscBool *krylovstart)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidPointer(krylovstart,2);

  ierr = PetscTryMethod(eps,"EPSGDGetKrylovStart_C",(EPS,PetscBool*),(eps,krylovstart));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDSetBlockSize"

/*@

   EPSGDSetBlockSize - Sets the number of vectors to be added to the searching space

   in every iteration.

   Logically Collective on EPS

   Input Parameters:

+  eps - the eigenproblem solver context

-  blocksize - number of vectors added to the search space in every iteration

   Options Database Key:

.  -eps_gd_blocksize - number of vectors added to the search space in every iteration

   Level: advanced

.seealso: EPSGDSetKrylovStart()

@*/

PetscErrorCode EPSGDSetBlockSize(EPS eps,PetscInt blocksize)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidLogicalCollectiveInt(eps,blocksize,2);

  ierr = PetscTryMethod(eps,"EPSGDSetBlockSize_C",(EPS,PetscInt),(eps,blocksize));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDGetBlockSize"

/*@

   EPSGDGetBlockSize - Returns the number of vectors to be added to the searching space

   in every iteration.

   Not Collective

   Input Parameter:

.  eps - the eigenproblem solver context

   Output Parameter:

.  blocksize - number of vectors added to the search space in every iteration

   Level: advanced

.seealso: EPSGDSetBlockSize()

@*/

PetscErrorCode EPSGDGetBlockSize(EPS eps,PetscInt *blocksize)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidIntPointer(blocksize,2);

  ierr = PetscTryMethod(eps,"EPSGDGetBlockSize_C",(EPS,PetscInt*),(eps,blocksize));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDGetRestart"

/*@

   EPSGDGetRestart - Gets the number of vectors of the searching space after

   restarting and the number of vectors saved from the previous iteration.

   Not Collective

   Input Parameter:

.  eps - the eigenproblem solver context

   Output Parameter:

+  minv - number of vectors of the searching subspace after restarting

-  plusk - number of vectors saved from the previous iteration  

   Level: advanced

.seealso: EPSGDSetRestart()

@*/

PetscErrorCode EPSGDGetRestart(EPS eps,PetscInt *minv,PetscInt *plusk)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidIntPointer(minv,2);

  PetscValidIntPointer(plusk,3);

  ierr = PetscTryMethod(eps,"EPSGDGetRestart_C",(EPS,PetscInt*,PetscInt*),(eps,minv,plusk));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDSetRestart"

/*@

   EPSGDSetRestart - Sets the number of vectors of the searching space after

   restarting and the number of vectors saved from the previous iteration.

   Logically Collective on EPS

   Input Parameters:

+  eps - the eigenproblem solver context

.  minv - number of vectors of the searching subspace after restarting

-  plusk - number of vectors saved from the previous iteration  

   Options Database Keys:

+  -eps_gd_minv - number of vectors of the searching subspace after restarting

-  -eps_gd_plusk - number of vectors saved from the previous iteration  

   Level: advanced

.seealso: EPSGDSetRestart()

@*/

PetscErrorCode EPSGDSetRestart(EPS eps,PetscInt minv,PetscInt plusk)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidLogicalCollectiveInt(eps,minv,2);

  PetscValidLogicalCollectiveInt(eps,plusk,2);

  ierr = PetscTryMethod(eps,"EPSGDSetRestart_C",(EPS,PetscInt,PetscInt),(eps,minv,plusk));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDGetInitialSize"

/*@

   EPSGDGetInitialSize - Returns the initial size of the searching space.

   Not Collective

   Input Parameter:

.  eps - the eigenproblem solver context

   Output Parameter:

.  initialsize - number of vectors of the initial searching subspace

   Notes:

   If EPSGDGetKrylovStart() is PETSC_FALSE and the user provides vectors with

   EPSSetInitialSpace(), up to initialsize vectors will be used; and if the

   provided vectors are not enough, the solver completes the subspace with

   random vectors. In the case of EPSGDGetKrylovStart() being PETSC_TRUE, the solver

   gets the first vector provided by the user or, if not available, a random vector,

   and expands the Krylov basis up to initialsize vectors.

   Level: advanced

.seealso: EPSGDSetInitialSize(), EPSGDGetKrylovStart()

@*/

PetscErrorCode EPSGDGetInitialSize(EPS eps,PetscInt *initialsize)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidIntPointer(initialsize,2);

  ierr = PetscTryMethod(eps,"EPSGDGetInitialSize_C",(EPS,PetscInt*),(eps,initialsize));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDSetInitialSize"

/*@

   EPSGDSetInitialSize - Sets the initial size of the searching space.

   Logically Collective on EPS

   Input Parameters:

+  eps - the eigenproblem solver context

-  initialsize - number of vectors of the initial searching subspace

   Options Database Key:

.  -eps_gd_initial_size - number of vectors of the initial searching subspace

   Notes:

   If EPSGDGetKrylovStart() is PETSC_FALSE and the user provides vectors with

   EPSSetInitialSpace(), up to initialsize vectors will be used; and if the

   provided vectors are not enough, the solver completes the subspace with

   random vectors. In the case of EPSGDGetKrylovStart() being PETSC_TRUE, the solver

   gets the first vector provided by the user or, if not available, a random vector,

   and expands the Krylov basis up to initialsize vectors.

   Level: advanced

.seealso: EPSGDGetInitialSize(), EPSGDGetKrylovStart()

@*/

PetscErrorCode EPSGDSetInitialSize(EPS eps,PetscInt initialsize)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidLogicalCollectiveInt(eps,initialsize,2);

  ierr = PetscTryMethod(eps,"EPSGDSetInitialSize_C",(EPS,PetscInt),(eps,initialsize));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDSetBOrth"

/*@

   EPSGDSetBOrth - Activates or deactivates the B-orthogonalizetion of the searching

   subspace in case of generalized Hermitian problems.

   Logically Collective on EPS

   Input Parameters:

+  eps - the eigenproblem solver context

-  borth - boolean flag

   Options Database Key:

.  -eps_gd_borth - Activates the B-orthogonalization of the searching subspace

   Level: advanced

.seealso: EPSGDGetBOrth()

@*/

PetscErrorCode EPSGDSetBOrth(EPS eps,PetscBool borth)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidLogicalCollectiveBool(eps,borth,2);

  ierr = PetscTryMethod(eps,"EPSGDSetBOrth_C",(EPS,PetscBool),(eps,borth));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDGetBOrth"

/*@

   EPSGDGetBOrth - Returns a flag indicating if the search subspace basis is

   B-orthogonalized.

   Not Collective

   Input Parameter:

.  eps - the eigenproblem solver context

   Output Parameters:

.  borth - the boolean flag

   Level: advanced

.seealso: EPSGDGetKrylovStart()

@*/

PetscErrorCode EPSGDGetBOrth(EPS eps,PetscBool *borth)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidPointer(borth,2);

  ierr = PetscTryMethod(eps,"EPSGDGetBOrth_C",(EPS,PetscBool*),(eps,borth));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDGetWindowSizes"

/*@

   EPSGDGetWindowSizes - Gets the number of converged vectors in the projected

   problem (or Rayleigh quotient) and in the projector employed in the correction

   equation.

   Not Collective

   Input Parameter:

.  eps - the eigenproblem solver context

   Output Parameter:

+  pwindow - number of converged vectors in the projector

-  qwindow - number of converged vectors in the projected problem

   Level: advanced

.seealso: EPSGDSetWindowSizes()

@*/

PetscErrorCode EPSGDGetWindowSizes(EPS eps,PetscInt *pwindow,PetscInt *qwindow)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidIntPointer(pwindow,2);

  PetscValidIntPointer(qwindow,3);

  ierr = PetscTryMethod(eps,"EPSGDGetWindowSizes_C",(EPS,PetscInt*,PetscInt*),(eps,pwindow,qwindow));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}

#undef __FUNCT__  

#define __FUNCT__ "EPSGDSetWindowSizes"

/*@

   EPSGDSetWindowSizes - Sets the number of converged vectors in the projected

   problem (or Rayleigh quotient) and in the projector employed in the correction

   equation.

   Logically Collective on EPS

   Input Parameters:

+  eps - the eigenproblem solver context

.  pwindow - number of converged vectors in the projector

-  qwindow - number of converged vectors in the projected problem

   Options Database Keys:

+  -eps_gd_pwindow - set the number of converged vectors in the projector

-  -eps_gd_qwindow - set the number of converged vectors in the projected problem  

   Level: advanced

.seealso: EPSGDGetWindowSizes()

@*/

PetscErrorCode EPSGDSetWindowSizes(EPS eps,PetscInt pwindow,PetscInt qwindow)

{

  PetscErrorCode ierr;

  PetscFunctionBegin;

  PetscValidHeaderSpecific(eps,EPS_CLASSID,1);

  PetscValidLogicalCollectiveInt(eps,pwindow,2);

  PetscValidLogicalCollectiveInt(eps,qwindow,3);

  ierr = PetscTryMethod(eps,"EPSGDSetWindowSizes_C",(EPS,PetscInt,PetscInt),(eps,pwindow,qwindow));CHKERRQ(ierr);

  PetscFunctionReturn(0);

}