db/dfb/_p_b___cindxg2p_8c_source.html

00001 /* ---------------------------------------------------------------------
00002 *
00003 *  -- PBLAS auxiliary routine (version 2.0) --
00004 *     University of Tennessee, Knoxville, Oak Ridge National Laboratory,
00005 *     and University of California, Berkeley.
00006 *     April 1, 1998
00007 *
00008 *  ---------------------------------------------------------------------
00009 */
00010 /*
00011 *  Include files
00012 */
00013 #include "../pblas.h"
00014 #include "../PBpblas.h"
00015 #include "../PBtools.h"
00016 #include "../PBblacs.h"
00017 #include "../PBblas.h"
00018
00019 #ifdef __STDC__
00020 int PB_Cindxg2p( int IG, int INB, int NB, int PROC, int SRCPROC, int NPROCS )
00021 #else
00022 int PB_Cindxg2p( IG, INB, NB, PROC, SRCPROC, NPROCS )
00023 /*
00024 *  .. Scalar Arguments ..
00025 */
00026    int            IG, INB, NB, NPROCS, PROC, SRCPROC;
00027 #endif
00028 {
00029 /*
00030 *  Purpose
00031 *  =======
00032 *
00033 *  PB_Cindxg2p computes the process coordinate  which posseses the entry
00034 *  of a matrix specified by a global index IG.
00035 *
00036 *  Arguments
00037 *  =========
00038 *
00039 *  IG      (global input) INTEGER
00040 *          On entry, IG specifies the global index of the matrix  entry.
00041 *          IG must be at least zero.
00042 *
00043 *  INB     (global input) INTEGER
00044 *          On entry,  INB  specifies  the size of the first block of the
00045 *          global matrix. INB must be at least one.
00046 *
00047 *  NB      (global input) INTEGER
00048 *          On entry, NB specifies the size of the blocks used to  parti-
00049 *          tion the matrix. NB must be at least one.
00050 *
00051 *  PROC    (local dummy) INTEGER
00052 *          On entry, PROC is a dummy argument in this case in  order  to
00053 *          unify the calling sequence of the tool-routines.
00054 *
00055 *  SRCPROC (global input) INTEGER
00056 *          On entry,  SRCPROC  specifies  the coordinate of the  process
00057 *          that possesses the  first row or column  of the matrix.  When
00058 *          SRCPROC = -1, the data  is not  distributed  but  replicated,
00059 *          otherwise  SRCPROC  must be at least zero and  strictly  less
00060 *          than NPROCS.
00061 *
00062 *  NPROCS  (global input) INTEGER
00063 *          On entry,  NPROCS  specifies the total number of process rows
00064 *          or columns over which the matrix is distributed.  NPROCS must
00065 *          be at least one.
00066 *
00067 *  -- Written on April 1, 1998 by
00068 *     Antoine Petitet, University of Tennessee, Knoxville 37996, USA.
00069 *
00070 *  ---------------------------------------------------------------------
00071 */
00072 /* ..
00073 *  .. Executable Statements ..
00074 *
00075 */
00076    if( ( IG < INB ) || ( SRCPROC == -1 ) || ( NPROCS == 1 ) )
00077 /*
00078 *  IG belongs to the first block, or the data is not distributed, or there is
00079 *  just one process in this dimension of the grid.
00080 */
00081       return( SRCPROC );
00082 /*
00083 *  Otherwise, IG is in block 1 + ( IG - INB ) / NB. Add this to SRCPROC and
00084 *  take the NPROCS modulo (definition of the block-cyclic data distribution).
00085 */
00086    PROC = SRCPROC + 1 + ( IG - INB ) / NB;
00087    return( MPosMod( PROC, NPROCS ) );
00088 /*
00089 *  End of PB_Cindxg2p
00090 */
00091 }