OTF2: improve support for mpi communicators
This commit fix the problem that happens if the tracing tool that generates a trace did not use an MPI communicator.
Prochaines maintenances programmées: lundi 06/05, lundi 03/06, lundi 01/07
Pour plus d'informations: https://doc-si.inria.fr/display/SU/Gitlab
This commit fix the problem that happens if the tracing tool that generates a trace did not use an MPI communicator.