Setup and Hello World example

1. The support for OpenMP has improved greatly in recent Gnu C compilers, so use a recent version, at least gcc 4.4 (you get a suitable version on the Beowulf nodes).

2. Copy omp_hello.c from section 3 of https://computing.llnl.gov/tutorials/openMP/exercise.html.

3. Review the source code and note how OpenMP directives and library routines are being used.

4. Log on to a multicore machine, e.g.
   bwlf12

5. Compile omp_hello.c for parallel execution:
   gcc -fopenmp omp_hello.c -o hello

6. Run with the default number of cores:
   ./hello

7. Set the number of cores to 4 and rerun:

   export OMP_NUM_THREADS=4
   ./hello
   

8. Log into jove and run hello again.