/*BHEADER**********************************************************************
 * Copyright (c) 2008,  Lawrence Livermore National Security, LLC.
 * Produced at the Lawrence Livermore National Laboratory.
 * This file is part of HYPRE.  See file COPYRIGHT for details.
 *
 * HYPRE is free software; you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License (as published by the Free
 * Software Foundation) version 2.1 dated February 1999.
 *
 * $Revision$
 ***********************************************************************EHEADER*/




/******************************************************************************
 *
 * Routine for building a DistributedMatrix from a ParCSRMatrix
 *
 *****************************************************************************/

#ifdef HYPRE_DEBUG
#include <gmalloc.h>
#endif

#include <HYPRE_config.h>

#include "general.h"

#include "HYPRE.h"
#include "HYPRE_utilities.h"

/* Prototypes for DistributedMatrix */
#include "HYPRE_distributed_matrix_types.h"
#include "HYPRE_distributed_matrix_protos.h"

/* Matrix prototypes for IJMatrix */
#include "IJ_mv/HYPRE_IJ_mv.h"

/* Local routine prototypes */
HYPRE_Int HYPRE_IJMatrixSetLocalStorageType(HYPRE_IJMatrix ij_matrix, 
                                      HYPRE_Int local_storage_type );

HYPRE_Int HYPRE_IJMatrixSetLocalSize(HYPRE_IJMatrix ij_matrix, 
                               HYPRE_Int row, HYPRE_Int col );

HYPRE_Int HYPRE_IJMatrixInsertRow( HYPRE_IJMatrix ij_matrix, 
                             HYPRE_Int size, HYPRE_Int i, HYPRE_Int *col_ind,
                             HYPRE_Real *values );

/*--------------------------------------------------------------------------
 * HYPRE_BuildIJMatrixFromDistributedMatrix
 *--------------------------------------------------------------------------*/
/**
Builds an IJMatrix from a distributed matrix by pulling rows out of the
distributed_matrix and putting them into the IJMatrix. This routine does not
effect the distributed matrix. In essence, it makes a copy of the input matrix
in another format. NOTE: because this routine makes a copy and is not just
a simple conversion, it is memory-expensive and should only be used in
low-memory requirement situations (such as unit-testing code). 
*/
HYPRE_Int 
HYPRE_BuildIJMatrixFromDistributedMatrix(
                 HYPRE_DistributedMatrix DistributedMatrix,
                 HYPRE_IJMatrix *ij_matrix,
                 HYPRE_Int local_storage_type )
{
   HYPRE_Int ierr;
   MPI_Comm comm;
   HYPRE_Int M, N;
   HYPRE_Int first_local_row, last_local_row;
   HYPRE_Int first_local_col, last_local_col;
   HYPRE_Int i;
   HYPRE_Int size, *col_ind;
   HYPRE_Real *values;



   if (!DistributedMatrix) return(-1);

   comm = HYPRE_DistributedMatrixGetContext( DistributedMatrix );
   ierr = HYPRE_DistributedMatrixGetDims( DistributedMatrix, &M, &N );

   ierr = HYPRE_DistributedMatrixGetLocalRange( DistributedMatrix, 
             &first_local_row, &last_local_row ,
             &first_local_col, &last_local_col );

   ierr = HYPRE_IJMatrixCreate( comm, first_local_row, last_local_row,
                                first_local_col, last_local_col,
                                ij_matrix );

   ierr = HYPRE_IJMatrixSetLocalStorageType( 
                 *ij_matrix, local_storage_type );
   /* if(ierr) return(ierr); */

   ierr = HYPRE_IJMatrixSetLocalSize( *ij_matrix, 
                last_local_row-first_local_row+1,
                last_local_col-first_local_col+1 );

   ierr = HYPRE_IJMatrixInitialize( *ij_matrix );
   /* if(ierr) return(ierr);*/

   /* Loop through all locally stored rows and insert them into ij_matrix */
   for (i=first_local_row; i<= last_local_row; i++)
   {
      ierr = HYPRE_DistributedMatrixGetRow( DistributedMatrix, i, &size, &col_ind, &values );
      /* if( ierr ) return(ierr);*/

      ierr = HYPRE_IJMatrixInsertRow( *ij_matrix, size, i, col_ind, values );
      /* if( ierr ) return(ierr);*/

      ierr = HYPRE_DistributedMatrixRestoreRow( DistributedMatrix, i, &size, &col_ind, &values );
      /* if( ierr ) return(ierr); */

   }

   ierr = HYPRE_IJMatrixAssemble( *ij_matrix );
   /* if(ierr) return(ierr); */

   return(ierr);
}