Basic HTML version of Foils prepared 6 December 96
| Actually in our MatMul program, nobody needs to call MPI_CART_COORDS |
| since they each know their i,j position, but each processor should |
| call MPI_CART_RANK to get a (possibly new) myrank. |
| One can also define subgroups that form lower-dimensional cartesian subgrids. In our case, we want to define the concept of "rows", so that we can shift along rows. |