MPI_Cart_shift(3)                     MPI                    MPI_Cart_shift(3)



NAME
       MPI_Cart_shift  -   Returns  the  shifted source and destination ranks,
       given a  shift direction and amount

SYNOPSIS
       #include "mpi.h"
       int MPI_Cart_shift ( MPI_Comm comm, int direction, int displ,
                           int *source, int *dest )

INPUT PARAMETERS
       comm   - communicator with cartesian structure (handle)
       direction
              - coordinate dimension of shift (integer)
       disp   - displacement (> 0: upwards shift, < 0: downwards shift) (inte-
              ger)


OUTPUT PARAMETERS
       rank_source
              - rank of source process (integer)
       rank_dest
              - rank of destination process (integer)


NOTES
       The  direction  argument  is  in the range [0,n-1] for an n-dimensional
       Cartesian mesh.


NOTES FOR FORTRAN
       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK )  have
       an  additional  argument ierr at the end of the argument list.  ierr is
       an integer and has the same meaning as the return value of the  routine
       in  C.   In Fortran, MPI routines are subroutines, and are invoked with
       the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
       Fortran.


ERRORS
       All  MPI  routines  (except  MPI_Wtime  and MPI_Wtick ) return an error
       value; C routines as the value of the function and Fortran routines  in
       the last argument.  Before the value is returned, the current MPI error
       handler is called.  By default, this error handler aborts the MPI  job.
       The  error  handler may be changed with MPI_Errhandler_set ; the prede-
       fined error handler MPI_ERRORS_RETURN may be used to cause error values
       to  be  returned.  Note that MPI does not guarentee that an MPI program
       can continue past an error.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_TOPOLOGY
              - Invalid topology.  Either there is no topology associated with
              this communicator, or it is not the correct type (e.g., MPI_CART
              when expecting MPI_GRAPH ).
       MPI_ERR_COMM
              - Invalid communicator.  A common error is to use a null  commu-
              nicator in a call (not even allowed in MPI_Comm_rank ).
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not identi-
              fied by a specific error class (e.g., MPI_ERR_RANK ).

LOCATION
       cart_shift.c



                                  11/14/2001                 MPI_Cart_shift(3)