18.2.38. MPI_Cart_rank
MPI_Cart_rank - Determines process rank in communicator given Cartesian location.
18.2.38.1. Syntax
18.2.38.1.1. C Syntax
#include <mpi.h>
int MPI_Cart_rank(MPI_Comm comm, int coords[], int *rank)
18.2.38.1.2. Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_CART_RANK(COMM, COORDS, RANK, IERROR)
INTEGER COMM, COORDS(*), RANK, IERROR
18.2.38.1.3. 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
18.2.38.2. 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.
18.2.38.3. Output Parameter
rank : Rank of specified process (integer).
IERROR : Fortran only: Error status (integer).
18.2.38.4. 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.
18.2.38.5. Errors
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. 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