Hello
Thanks for your help.
MPI_UNDEFINED lead me to a better understanding and control on all my
communicators. I used now only MPI_Comm_Split (before i was trying with
MPI_Group_incl which complicated things )
Others errors were caused by a non-mpi-related mistake.
It works well now, than
Mathieu,
All communicator creation function in the MPI 2.2 standard are collective over
the original communicator. For your specific case this means all processes in
the worker communicator must call the communicator creation functions.
As this is true in all cases, and as a communicator creati
