Creating a 3D topology

Creating a 3D Topology

• A 3D virtual topology may be created as follows:

int dims[3]={0,0,0}, periods[3]={0,1,1};
int reorder=0, nprocs, ierr;
MPI_Comm comm, comm3d;

ierr = MPI_Comm_size (comm, &nprocs);
ierr = MPI_Dims_create (nprocs, ndims, dims);
ierr = MPI_Cart_create (comm, ndims, dims,
                        periods, reorder, comm3d);