[Mpi3-hybridpm] MPI + threads / MPI +OpenMP

[Rajeev Thakur]

Some questions just for clarification:

* What does MPI_Comm_size of MPI_COMM_TWORLD return -- the total number
of end points on all processes?

* For collective operations on MPI_COMM_TWORLD, how many
processes/threads must call them -- exactly one for each end point? If
each process has 11 threads and 5 end points say, the user has to ensure
that exactly 5 threads on each process call the collective, one for each
end point?

Rajeev