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

Instructions to load the modules for the various versions of MPI are below. 
Note that you need to be careful to have the right version loaded (the one you compiled the
NPmpi with) when you are running the tests. You should also ensure that no other version is
loaded.   

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

-----------
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 NPmpi by doing
make mpi


To run NPmpi do

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 node1 it should contain
node1
node2



-------------
If you are running MPI over infiniband do
module load  mpi2/ib/openmpi-gcc
module initadd  mpi2/ib/openmpi-gcc


You can then compile NPmpi by doing
make mpi 

To run NPmpi do
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 node1 it should contain
inode1
inode2


---------------
The other available versions of MPI  (for gcc and the Portland compiler are pgi7.1 ) are

MPICH over Gigabit ethernet
mpi1/enet/mpich-gcc     
mpi1/enet/mpich-pgi7.1

MPICH2 over Gigabit ethernet
mpi2/enet/mpich2-gcc    
mpi2/enet/mpich2-pgi7.1 

OpemMPI over Infiniband
mpi2/ib/openmpi-gcc
mpi2/ib/openmpi-pgi7.1 

MVAPICH over Infiniband
mpi1/ib/mvapich-pgi7.1   
mpi1/ib/mvapich-gcc 

MVAPICH2 over Infiniband
mpi2/ib/mvapich2-gcc      
mpi2/ib/mvapich2-pgi7.1