mpi_cart_get(3openmpi) [osx man page]

MPI_Cart_get(3OpenMPI)													    MPI_Cart_get(3OpenMPI)

NAME

       MPI_Cart_get -  Retrieves Cartesian topology information associated with a communicator.

SYNTAX

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

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_CART_GET(COMM, MAXDIMS, DIMS, PERIODS, COORDS, IERROR)
	    INTEGER   COMM, MAXDIMS, DIMS(*), COORDS(*), IERROR
	    LOGICAL   PERIODS(*)

C++ Syntax
       #include <mpi.h>
       void Cartcomm::Get_topo(int maxdims, int dims[],
	    bool periods[], int coords[]) const

INPUT PARAMETERS

       comm	 Communicator with Cartesian structure (handle).

       maxdims	 Length of vectors dims, periods, and coords in the calling program (integer).

OUTPUT PARAMETERS

       dims	 Number of processes for each Cartesian dimension (array of integers).

       periods	 Periodicity (true/false) for each Cartesian dimension (array of logicals).

       coords	 Coordinates of calling process in Cartesian structure (array of integers).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       The  functions  MPI_Cartdim_get	and  MPI_Cart_get  return  the	Cartesian  topology information that was associated with a communicator by
       MPI_Cart_create.

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++ func-
       tions  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_Cartdim_get
       MPI_Cart_create

Open MPI 1.2							  September 2006					    MPI_Cart_get(3OpenMPI)

MPI_Cart_create(3OpenMPI)												 MPI_Cart_create(3OpenMPI)

NAME

       MPI_Cart_create - Makes a new communicator to which Cartesian topology information has been attached.

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Cart_create(MPI_Comm comm_old, int ndims, int *dims,
	    int *periods, int reorder, MPI_Comm *comm_cart)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_CART_CREATE(COMM_OLD, NDIMS, DIMS, PERIODS, REORDER,
		 COMM_CART, IERROR)
	    INTEGER   COMM_OLD, NDIMS, DIMS(*), COMM_CART, IERROR
	    LOGICAL   PERIODS(*), REORDER

C++ Syntax
       #include <mpi.h>
       Cartcomm Intracomm::Create_cart(int ndims, const int dims[],
	    const bool periods[], bool reorder) const

INPUT PARAMETERS

       comm_old  Input communicator (handle).

       ndims	 Number of dimensions of Cartesian grid (integer).

       dims	 Integer array of size ndims specifying the number of processes in each dimension.

       periods	 Logical array of size ndims specifying whether the grid is periodic (true) or not (false) in each dimension.

       reorder	 Ranking may be reordered (true) or not (false) (logical).

OUTPUT PARAMETERS

       comm_cart Communicator with new Cartesian topology (handle).

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Cart_create returns a handle to a new communicator to which the Cartesian topology information is attached. If reorder = false then the
       rank of each process in the new group is identical to its rank in the old group. Otherwise, the function may reorder the processes  (possi-
       bly so as to choose a good embedding of the virtual topology onto the physical machine). If the total size of the Cartesian grid is smaller
       than the size of the group of comm, then some processes are returned MPI_COMM_NULL, in analogy to MPI_Comm_split. The call is erroneous	if
       it specifies a grid that is larger than the group size.

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++ func-
       tions 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.

Open MPI 1.2							  September 2006					 MPI_Cart_create(3OpenMPI)