I think the issue is with the way you define the send and receive buffer in the MPI_Alltoall. You have to keep in mind that the all-to-all pattern will overwrite the entire data in the receive buffer. Thus, starting from a relative displacement in the data (in this case matrix[wrank*wrows]), begs for troubles, as you will write outside the receive buffer.
George. On Thu, May 8, 2014 at 10:08 AM, Matthieu Brucher <matthieu.bruc...@gmail.com> wrote: > The Alltoall should only return when all data is sent and received on > the current rank, so there shouldn't be any race condition. > > Cheers, > > Matthieu > > 2014-05-08 15:53 GMT+02:00 Spenser Gilliland <spen...@gillilanding.com>: >> George & other list members, >> >> I think I may have a race condition in this example that is masked by >> the print_matrix statement. >> >> For example, lets say rank one has a large sleep before reaching the >> local transpose, will the other ranks have completed the Alltoall and >> when rank one reaches the local transpose it is altering the data that >> the other processors sent it? >> >> Thanks, >> Spenser >> >> >> -- >> Spenser Gilliland >> Computer Engineer >> Doctoral Candidate >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > > > -- > Information System Engineer, Ph.D. > Blog: http://matt.eifelle.com > LinkedIn: http://www.linkedin.com/in/matthieubrucher > Music band: http://liliejay.com/ > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
