NAME

       MPI_Cart_rank  -  Determines process rank in communicator given Cartesian location.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Cart_rank(MPI_Comm comm, int coords[], int *rank)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_CART_RANK(COMM, COORDS, RANK, IERROR)
            INTEGER   COMM, COORDS(*), RANK, IERROR

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Cart_rank(comm, coords, rank, ierror)
            TYPE(MPI_Comm), INTENT(IN) :: comm
            INTEGER, INTENT(IN) :: coords(*)
            INTEGER, INTENT(OUT) :: rank
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

       #include <mpi.h>
       int Cartcomm::Get_cart_rank(const int coords[]) const

INPUT PARAMETERS

       comm      Communicator with Cartesian structure (handle).

       coords    Integer  array  (of  size  ndims,  which  was  defined  by MPI_Cart_create call)
                 specifying the Cartesian coordinates of a process.

OUTPUT PARAMETER

       rank      Rank of specified process (integer).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       For a process group with Cartesian structure, the function  MPI_Cart_rank  translates  the
       logical  process  coordinates  to  process  ranks  as  they are used by the point-to-point
       routines.  For dimension i with periods(i) = true, if the coordinate, coords(i), is out of
       range, that is, coords(i) < 0 or  coords(i) >= dims(i), it is shifted back to the interval
       0 =< coords(i)  <  dims(i)  automatically.  Out-of-range  coordinates  are  erroneous  for
       nonperiodic dimensions.

ERRORS

       Almost all MPI routines return an error value; C routines as the value of the function and
       Fortran routines in the last argument. C++ functions do not return errors. If the  default
       error  handler  is  set  to  MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception
       mechanism will be used to throw an MPI::Exception object.

       Before the error value is returned, the current MPI error handler is called.  By  default,
       this  error  handler aborts the MPI job, except for I/O function errors. The error handler
       may   be   changed   with   MPI_Comm_set_errhandler;   the   predefined   error    handler
       MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not
       guarantee that an MPI program can continue past an error.

SEE ALSO

       MPI_Cart_create