MPIRUN fails to launch multiple processus
I'm currently having an issue with my MPI runtime. At installation my MPI installation behaved normally and as expected, ie :
$mpirun -np 4 my_program
was indeed launching 4 instances/nodes of "my_program", on a single core, multicore or multi-system cloud.
Now it's only capable of launching a single instance no matter what argument I give to the -np option. I haven't changed any parameters in my installation (Ubuntu 10.04)... at least not consciously. Anybody has an idea what might be behind this issue ?
My teacher and fellow students are all puzzled and can't get a grip on it too.