This includes two changes. 1) Update trestles to use OpenMPI instead of MVAPICH. 2) FIX a huge bug where ghost zone reading conditionals were backwards. This would cause stripes, NaNs, etc etc, and should result in a crash. This fixes that issue. Note that existing data is not corrupt.
Thanks for catching this, Matt. I'm partially at fault, too, because I didn't catch this when I accepted the original pull request.