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/* ---------------------------------------------------------------------
*
* -- PBLAS auxiliary routine (version 2.0) --
* University of Tennessee, Knoxville, Oak Ridge National Laboratory,
* and University of California, Berkeley.
* April 1, 1998
*
* ---------------------------------------------------------------------
*/
/*
* Include files
*/
#include "../pblas.h"
#include "../PBpblas.h"
#include "../PBtools.h"
#include "../PBblacs.h"
#include "../PBblas.h"
#ifdef __STDC__
int PB_Cindxg2p( int IG, int INB, int NB, int PROC, int SRCPROC, int NPROCS )
#else
int PB_Cindxg2p( IG, INB, NB, PROC, SRCPROC, NPROCS )
/*
* .. Scalar Arguments ..
*/
int IG, INB, NB, NPROCS, PROC, SRCPROC;
#endif
{
/*
* Purpose
* =======
*
* PB_Cindxg2p computes the process coordinate which posseses the entry
* of a matrix specified by a global index IG.
*
* Arguments
* =========
*
* IG (global input) INTEGER
* On entry, IG specifies the global index of the matrix entry.
* IG must be at least zero.
*
* INB (global input) INTEGER
* On entry, INB specifies the size of the first block of the
* global matrix. INB must be at least one.
*
* NB (global input) INTEGER
* On entry, NB specifies the size of the blocks used to parti-
* tion the matrix. NB must be at least one.
*
* PROC (local dummy) INTEGER
* On entry, PROC is a dummy argument in this case in order to
* unify the calling sequence of the tool-routines.
*
* SRCPROC (global input) INTEGER
* On entry, SRCPROC specifies the coordinate of the process
* that possesses the first row or column of the matrix. When
* SRCPROC = -1, the data is not distributed but replicated,
* otherwise SRCPROC must be at least zero and strictly less
* than NPROCS.
*
* NPROCS (global input) INTEGER
* On entry, NPROCS specifies the total number of process rows
* or columns over which the matrix is distributed. NPROCS must
* be at least one.
*
* -- Written on April 1, 1998 by
* Antoine Petitet, University of Tennessee, Knoxville 37996, USA.
*
* ---------------------------------------------------------------------
*/
/* ..
* .. Executable Statements ..
*
*/
if( ( IG < INB ) || ( SRCPROC == -1 ) || ( NPROCS == 1 ) )
/*
* IG belongs to the first block, or the data is not distributed, or there is
* just one process in this dimension of the grid.
*/
return( SRCPROC );
/*
* Otherwise, IG is in block 1 + ( IG - INB ) / NB. Add this to SRCPROC and
* take the NPROCS modulo (definition of the block-cyclic data distribution).
*/
PROC = SRCPROC + 1 + ( IG - INB ) / NB;
return( MPosMod( PROC, NPROCS ) );
/*
* End of PB_Cindxg2p
*/
}
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