On Sep 23, 2010, at 6:28 AM, Gabriele Fatigati wrote: > i'm studing the interfaces of new collective routines in next MPI-3, and i've > read that new collectives haven't any tag.
Correct. > So all collective operations must follow the ordering rules for collective > calls. Also correct. > From what i understand, this means that i can't use: > > MPI_IBcast(MPI_COMM_WORLD, request_1) // first Bcast > MPI_IBcast(MPI_COMM_WORLD, request_2) // second Bcast No, not quite right. You can have multiple outstanding ibcast's -- they'll just be satisfied in the same order in all participating MPI processes. > but is it possible to do this: > > MPI_IBcast(MPI_COMM_WORLD, request_1) // first Bcast > MPI_IReducet(MPI_COMM_WORLD, request_2) // othwer collective Correct -- this is also possible. More generally, you can have multiple outstanding non-blocking collectives on a single communicator -- it doesn't matter if they are the same or different collective operations. They will each be unique instances and will be satisfied in order. -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
