infog1l.f

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      SUBROUTINE infog1l( GINDX, NB, NPROCS, MYROC, ISRCPROC, LINDX,
     $                    ROCSRC )
*
*  -- ScaLAPACK tools routine (version 1.7) --
*     University of Tennessee, Knoxville, Oak Ridge National Laboratory,
*     and University of California, Berkeley.
*     May 1, 1997
*
*     .. Scalar Arguments ..
      INTEGER            GINDX, ISRCPROC, LINDX, MYROC, NB, NPROCS,
     $                   rocsrc
*     ..
*
*  Purpose
*  =======
*
*  INFOG1L computes the starting local indexes LINDX corresponding to
*  the distributed submatrix starting globally at the entry pointed by
*  GINDX.  This routine returns the coordinates of the process in the
*  grid owning the submatrix entry of global index GINDX: ROCSRC.
*  INFOG1L is a 1-dimensional version of INFOG2L.
*
*  Arguments
*  =========
*
*  GINDX     (global input) INTEGER
*            The global starting index of the submatrix.
*
*  NB        (global input) INTEGER
*            The block size.
*
*  NPROCS    (global input) INTEGER
*            The total number of processes over which the distributed
*            submatrix is distributed.
*
*  MYROC     (local input) INTEGER
*            The coordinate of the process calling this routine.
*
*  ISRCPROC  (global input) INTEGER
*            The coordinate of the process having the first entry of
*            the distributed submatrix.
*
*  LINDX     (local output) INTEGER
*            The local starting indexes of the distributed submatrix.
*
*  ROCSRC    (global output) INTEGER
*            The coordinate of the process that possesses the first
*            row and column of the submatrix.
*
*  =====================================================================
*
*     .. Local Scalars ..
      INTEGER            GCPY, IBLK
*     ..
*     .. Intrinsic Functions ..
      INTRINSIC          mod
*     ..
*     .. Executable Statements ..
*
      gcpy = gindx-1
      iblk = gcpy / nb
      rocsrc = mod( iblk + isrcproc, nprocs )
*
      lindx = ( iblk / nprocs + 1 ) * nb + 1
*
      IF( mod(myroc+nprocs-isrcproc,nprocs).GE.mod(iblk, nprocs) ) THEN
         IF( myroc.EQ.rocsrc )
     $      lindx = lindx + mod( gcpy, nb )
         lindx = lindx - nb
      END IF
*
      RETURN
*
*     End of INFOG1L
*
      SUBROUTINE infog1l( GINDX, NB, NPROCS, MYROC, ISRCPROC, LINDX, …
      END