IMPLICIT DOUBLE PRECISION (A-H,O-Z)
      INCLUDE 'mpif.h'
      INTEGER RTYPE
      PARAMETER (RTYPE=MPI_DOUBLE_PRECISION)
*
***      IMPLICIT REAL (A-H,O-Z)
***      INCLUDE 'mpif.h'
***      INTEGER RTYPE
***      PARAMETER (RTYPE=MPI_REAL)
*
* NPROCS:		total number of processors
* NP, NQ:		processor grid, NP*NQ = NPROCS
* COMM:			communicator with 2D Cartesian topology
* RANK_X, RANK_Y:	Cartesian coordinates in COMM.
* MYRANK:		my rank in COMM
* NGLOB, MGLOB: 	total grid points
* NLOCA, MLOCA: 	local grid points
* IOFFSET, JOFFSET:	coordinates of lower-left corner in the global grid.
*
      INTEGER NPROCS, NP, NQ, MYRANK, NGLOB, MGLOB, NLOCA, MLOCA,
     +        COMM, RANK_X, RANK_Y, IOFFSET, JOFFSET
      COMMON /PARMS/ NPROCS, NP, NQ, MYRANK, NGLOB, MGLOB, NLOCA, MLOCA,
     +               COMM, RANK_X, RANK_Y, IOFFSET, JOFFSET