Why Do All My Open MPI Processes Have Rank 0?

Question

I\'m writing a parallel program using Open MPI. I\'m running Snow Leopard 10.6.4, and I installed Open MPI through the homebrew package ma

Answer 1

Check which mpirun you are invoking. The mpirun that is being executed is launching 8 independent instances of the binary. So each instance is an MPI application with a universe size of 1 and rank 0.

Also, unless you are planning to run the final code on a cluster of OS X boxes, I highly recommend installing a Linux version in a VM, like virtualbox, to test & develop these codes.