There are a number of different versions of MPI on gandalf.
There are also 2 compilers the GNU compilers such as gcc and the Portland (PGI) compilers
such as pgcc and pgf77.

By default the GNU compilers are the ones used.
You do not need it for this assignment, but to make the PGI compilers the default do
module load compilers/64/pgi7.1

The module command sets certain environment variables, and paths to directories for executables,
libraries, include files, and man pages.            

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If you are running MPI over the gigabit ethernet do
module load mpi1/enet/mpich-gcc  
module initadd mpi1/enet/mpich-gcc  

You can then compile mm.c  by doing
mpicc -o mm mm.c


To run mm ssh into the first node in your hosts file (node13 in our case) and there
type the mpirun command below that is 

ssh node13 


mpirun -machinefile hosts -np 2 NPmpi

where hosts is a file containing the names of the nodes you are running on. Note
the first should be the node you are logged into and running from. For example if you are
logged into node13 it should contain node13 as the first entry.

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