How To Set Up Your Linux Account to Use Mpi
===========================================

Carefully follow the steps below. A ">" indicates your prompt, which
doesn't need to be typed.

0)

Generate a public/private key pair for logging into other machines in the 
cluster without using a password.

>ssh-keygen

Accept the default key file of ~/.ssh/id_rsa by pressing return.
Use an empty passphrase, so press enter in response to the next question.
Enter the empty passphrase a second time.

1)

Copy your public key into ~/.ssh/authorized_keys.

>cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys


2) 

Logon to another machine and verify that a password isn't necessary.

>ssh boole

You will be asked if you want to continue connecting. Enter "yes".

If you are prompted for a password then you incorrectly entered one of 
the previous commands. Either try again or contact me.

Logout from the remote machine.

>exit

3)

Copy the "GenHostFile.sh" script to your directory. Run it to create a
"Hosts.txt" file that lists all of the available machines (ideally all
are online, but typically some are not).

Copy the hosts file to a directory you will use for MPI development
(e.g., ~/476). Later you can create subdirectories for different
programs, but use this directory for the host file.

4)

Compile and launch programs as follows. Modify your Makefile so that
CXX = mpicxx.

>mpicxx -Wall Hello.cc -o Hello

>mpirun -n <number of processes> -hostfile ./Hosts.txt ./Hello