Opening a HDF5File using a single process

Question

Hi,

I am using the Hierarchical Data Format to store meshes and solutions and it works great. I am wondering if it is possible to open/read the files using a single process, in an environment where there are multiple processes. I.e.

from dolfin import MPI, HDF5File

if MPI.process_number() == 0:
    f = HDF5File("u.h5","r")

"mpirun -n 2 python mpitest.py" will hang, presumably because it is waiting for the other processes to get involved even though they have been excluded.

My question: Is there a clean way to give a mesh or function defined on multiple processes to a single process?

Answer 1

There isn't yet a clean way to move meshes, etc between processes. We have recently added the MPI communicator as an argument to many classes, which will make varying the number processes, moving a distributed mesh to one process, etc, possible in the near future.

Comments

Is there an 'unclean' workaround in the meantime?