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

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.