Create mpi_omp_hello.cpp

This routine parallelizes using both MPI and OpenMP. OpenMP allows multiple processes using the same memory (typically one thread per core on a single machine). MPI allows parallel threads to run each with their own memory, typically each on their own machine (so there is physically no memory that could be shared). To compile and run:
module load impi/intel
mpixx mpi_omp_hello.cpp -fopenmp
export OMP_NUM_THREADS=4
mpirun -np 4 ./a.out