mpi.cart.create returns 1 if success and 0 otherwise.
Arguments
commold
Input communicator
dims
Integery array of size ndims specifying the number of processes in
each dimension
periods
Logical array of size ndims specifying whether the grid is periodic
or not in each dimension
reorder
ranks may be reordered or not
commcart
The new communicator to which the Cartesian topology information is attached
Author
Alek Hunchak and Hao Yu
Details
If reorder = false, then the rank of each process in the new group is the same
as its rank in the old group. If the total size of the Cartesian grid is smaller
than the size of the group of commold, then some processes are returned
mpi.comm.null. The call is erroneous if it specifies a grid that is larger than
the group size.