Makes a new communicator to which topology information has been attached


#include "mpi.h"
int MPI_Cart_create ( MPI_Comm comm_old, int ndims, int *dims, int *periods, 
                     int reorder, MPI_Comm *comm_cart )

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 Parameter

communicator with new cartesian topology (handle)


We ignore reorder info currently.

Notes for Fortran

All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK) have an additional argument ierr at the end of the argument list. ierr is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked with the call statement.

All MPI objects (e.g., MPI_Datatype, MPI_Comm) are of type INTEGER in Fortran.


All MPI routines (except MPI_Wtime and MPI_Wtick) return an error value; C routines as the value of the function and Fortran routines in the last argument. Before the value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job. The error handler may be changed with MPI_Errhandler_set; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error.

No error; MPI routine completed successfully.
Invalid topology. Either there is no topology associated with this communicator, or it is not the correct type (e.g., MPI_CART when expecting MPI_GRAPH).
Illegal dimension argument. A dimension argument is null or its length is less than or equal to zero.
Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., MPI_ERR_RANK).