On the HPC cluster, by default all Message Passing Interface libraries are configured to use the infiniband network to pass data. No special user knowledge or action is required to use the infiniband network.

In the next few sections we will show how to run parallel jobs using the three different MPI implementations that are installed on the cluster. The files for these examples can be found in the directory /panfs/storage.local/system/tutorial/example2. The code that we use in these examples, trap.c, is a simple trapezoid integration program.

The user is free to choose which MPI library and compiler best suits his or her needs. However, when one compiles a program with a certain library and compiler, it is best to run the program with these tools. In the following examples you can switch compilers by substituting intel for gnu and vice versa.