Running and Debugging

Run your code ``poisson.c'' and verify that you recover the analytic solution with the expected scaling in the error.

Note: You may wish to add another entry to your makefile:

poisson: poisson.c p480.o nrutil.o p480.h nrutil.h
        cc -o poisson poisson.c p480.o nrutil.o -lm

Then, be sure to compile and run your code with the commands ``make poisson'' and ``poisson''.