Once a parallel program computes a solution, it it often necessary to write the solution out to disk or display it on the user's terminal. This often means collecting the data onto a single processor that handles performing the output (since there are few parallel file systems around). This exercise shows one way in which this may be performed. Take your Jacobi iteration example and modify it so that the computed solution is collected onto process 0, which then writes the solution out (to standard output). You might want to write the results out in a form that can be used for display with tools like gnuplot or matlab, but this is not required. You may assume that process zero can store the entire solution. Also, assume that each process contributes exactly the same amount of data (see the related problems for the general case).

You may want to use these MPI routines in your solution:
MPI_Gather