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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_Cspan( int N, int I, int INB, int NB, int SRCPROC, int NPROCS )
#else
int PB_Cspan( N, I, INB, NB, SRCPROC, NPROCS )
/*
* .. Scalar Arguments ..
*/
int I, INB, N, NB, NPROCS, SRCPROC;
#endif
{
/*
* Purpose
* =======
*
* PB_Cspan returns 1 if the rows (resp. columns) I:I+N-1 spans more
* than one process row (resp. column) and 0 otherwise.
*
* Arguments
* =========
*
* N (global input) INTEGER
* On entry, N specifies the number of rows/columns being dealt
* out. N must be at least zero.
*
* I (global input) INTEGER
* On entry, I specifies the global index of the matrix entry.
* I must be at least zero.
*
* INB (global input) INTEGER
* On entry, INB specifies the size of the first block of the
* global matrix distribution. 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.
*
* SRCPROC (global input) INTEGER
* On entry, if SRCPROC = -1, the data is not distributed but
* replicated, in which case this routine return 0.
*
* 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 the data is replicated or if there is only one process in this dimension
* of the process grid, the data does not span multiple processes. Finally, the
* case where I belongs to the first block is handled separately.
*/
return( ( SRCPROC >= 0 ) &&
( ( NPROCS > 1 ) &&
( ( I < INB ) ? ( I + N > INB ) :
( I + N > INB + ( ( I - INB ) / NB + 1 ) * NB ) ) ) );
/*
* End of PB_Cspan
*/
}
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