MPI parallelization not possible with depletion in OpenMC #122
Description
When trying to run a memory intensive job such as depletion with WATTS, it's helpful to run jobs that use both OpenMP threads and MPI processes. I've recreated an example using two mpi processes.
CWD after depletion function is passed into plugin is called: /tmp/tmpr7dpntnx
CWD after depletion function is passed into plugin is called: /tmp/tmpftqlix2t
It seems this is an issue with mpi optimization not being made in mind, specifically with cd_tmpdir and move_files in fileutils.py and results.py, respectively. If I try to launch a script with mpi processes, WATTS will create two separate tmp directories, which creates reading issues for statepoint files. I believe solution would be mpi implementation into cd_tmpdir and move_files, at least for openmc.