When creating a Cartesian topology, one question is ``What is a good choice for the decomposition of the processors?''
This question can be answered with MPI_Dims_create:
integer dims(2) dims(1) = 0 dims(2) = 0 call MPI_COMM_SIZE( MPI_COMM_WORLD, size, ierr ) call MPI_DIMS_CREATE( size, 2, dims, ierr )