MPI sometimes doesn't exit when exceptions are thrown in Python

[bburke38]

Just experienced this issue when running an aeroelastic optimization case, which after manually killing the job showed that it hung on the following code in fun3d_interface.py:

# throw a runtime error if adjoint didn't converge sufficiently
if abs(resid) > self.forward_tolerance:
    raise RuntimeError(
        f"Funtofem/Fun3dInterface: fun3d forward flow residual = {resid} > {self.forward_tolerance:.2e}, is too large..."
    )

This is a known issue in mpi4py (here). A simple fix seems to be to modify the execution call with the addition of -m mpi4py:

mpiexec -n ${nprocs} python -m mpi4py script.py 2>&1> output.txt