[mpich-discuss] What is the difference between MPI_THREAD_SINGLE and MPI_THREAD_FUNNELED

[Boisvert, Sebastien]

Hi MPICH community:

With MPICH, if my MPI process has 10 threads (including the main thread) and only the main thread
calls MPI functions, do I need to use MPI_THREAD_SINGLE or MPI_THREAD_FUNNELED 
when I invoke MPI_Init_thread ?

Thanks a ton !