MPI_Cart_get(3)

NAME
MPI_Cart_get - Returns the dimension, period and coordinate information in the cartesian communicator

SYNOPSIS
#include <mpi.h>
int MPI_Cart_get(MPI_Comm comm, int maxdims, int *dims, int *periods, int *coords);

#include <pmpi.h>
int PMPI_Cart_get(MPI_Comm comm, int maxdims, int *dims, int *periods, int *coords);

#include <mpi.h>
void MPI::Cartcomm::Get_topo(int maxdims, int *dims, bool *periods, int *coords) const;

INCLUDE 'mpif.h'
MPI_CART_GET(comm, maxdims, dims, periods, coords, ierr)
INTEGER comm, maxdims, dims(*), periods(*), coords(*), ierr

INPUT PARAMETERS
comm
    - cartesian communicator (handle)
maxdims
    - size of the output arrays (integer)

OUTPUT PARAMETERS
dims
    - size of the dimensions (array).
periods
    - periodicity information for each dimension (array).
coords
    - this rank's coordinates for each dimension (array).

DESCRIPTION
The MPI_Cart_get() function is used to obtain the dimensions, periodicity and current coordinate information from a cartesian communicator. The output arrays are maxdims in size, and if more dimensions than this exist, this function will return MPI_ERR_DIMS. Otherwise, the dims, periods and coords arrays are filled with the required information. The communicator must be a valid one (not MPI_COMM_NULL). PMPI_Cart_get() is the profiling version of this function.

ERRORS
All MPI routines except for MPI_Wtime and MPI_Wtick return an error code. The the current MPI error handler is invoked if the return value is not MPI_SUCCESS. The default error handler aborts, but this may be changed with by using the MPI_Errhandler_set() function. The predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned instead. Note that MPI does not guarentee that an MPI program can continue past an error. In this implementation, all errors except MPI_ERR_INTERN or MPI_ERR_OTHER should always be recoverable. In C, the error code is passed as the return value. In FORTRAN, all functions have an parameter ierr which returns the error code. MPI C++ functions do not directly return an error code. However, C++ users may want to use the MPI::ERRORS_THROW_EXCEPTIONS handler. This will throw an MPI::Exception with the corresponding error code. To prevent exceptions from being raised from within C and Fortran code, they will see all error return values as MPI_ERR_PENDING when this handler is chosen. In this implementation, call MPI::throw_exception() to throw the correct exception if this occurs.
MPI_SUCCESS
    - No error;
MPI_ERR_PENDING
    - Pending exception;
MPI_ERR_COMM
    - Invalid communicator;
MPI_ERR_TOPOLOGY
    - Not a cartesian communicator;
MPI_ERR_DIMS
    - Invalid output dimension array pointer;
MPI_ERR_ARG
    - Invalid output pointer.

SEE ALSO
MPI_Cart_create(3), MPI_Cartdim_get(3), MPI_Dims_create(3), MPI_Cart_map(3), MPI_Graph_create(3), MPI_Graphdims_get(3), MPI_Comm_free(3)