TOPIC: [continuation of session3] Domain Decomposition Technique
GOAL:  Jacobi Iteration of a 2D Poisson Problem
CODE:  jacobi/.

The second tasks is to modify the sequential version of the Jacobi
program such that each processor works only on local data. This means
that we simply need to adapt all declarations, loop counts and
subroutine arguments such as to take into account local data sizes.

In the third and final step, we implement the necessary communication
of ghost-cell data. There are many different possibilities for doing
this (blocking in different pre-defined orders, non-blocking).

We will discuss efficiency measures and perform timing of our code.