Running MPICH

From Bootable Cluster CD

MPICH is usually the default...

Good news! At the time of this writing, the BCCD is already set up with MPICH as the default environment. On other systems, or to double check, to find out if MPICH is your default environment, issue the command:

which mpirun

If it comes back saying:

/mpich/bin/mpirun

then that means you are good to go and can skip to the next part! But if you received any other result, you must read on.

If not...

Edit the User's Path Variable

We need to set the bccd user's PATH setting to point to the MPICH binaries. To do this, we need to modify the PATH seting in the bccd user's .bashrc file:

vi ~/.bashrc

Look for the line that starts with:

export PATH=(something...)

and change it to read:

export PATH=$PATH:/mpich/bin

Allow the Changes to Take Effect

Log out of every shell, or source your .bashrc. Changes in your .bashrc settings do not take effect immediately. These changes will "stick" the next time you log in, or if you do what is referred to as "sourcing your .bashrc file". So you will have to do one of the following actions:

• Shutdown X and/or log out of every shell. Then log back in.
• Or issue

. ~/.bashrc

Once Again...

Once again, issue:

which mpirun

and if everything went a-ok you should get:

/mpich/bin/mpirun

Now go on!

Compiling and Running an MPI Program

Now that your environment is set, click on Compiling and Running to learn how to run a sample MPI program. Or, take a look at some MPICH debuggers, such as Debugging with MPE or Debugging with Upshot. Remember, all the example MPICH programs are in the directory ~/mpich/examples/, and are ready to be run after a simple make command!