title: OpenMPI: All nodes run as node 0
body: <p>I have a c++ program that is using the openMPI library to pass messages between different processors.  It is a parallel program that uses a genetic algorithm to get a good solution for the traveling salesperson problem.  I am trying to set up the MPI environment on my two dual processor computers at my house so that I can run it.
     When I first created this program a year ago, I was able to run it fine on a cluster that was not set up by me.  The problem that I am having now is that whenever I run it, all the processes are saying that they are of rank 0.  If I have 3 nodes, instead of them being nodes 1, 2, and 3, they are all node 0.  If anyone knows what is going on, I would sure appreciate some help.  Thanks.</p>