Rolf let’s open a Ticket Anthony Skjellum, PhD 205-807-4968
> On Sep 27, 2019, at 6:09 PM, Rolf Rabenseifner via mpi-forum > <mpi-forum@lists.mpi-forum.org> wrote: > > Dear MPI collective WG, > > you may try to resolve the problem with a maybe wrong > MPI specification for MPI_NEIGHBOR_ALLTOALL/ALLGATHER > > Dear MPI Forum member, > > you may own/use an MPI implementation that implements > MPI_NEIGHBOR_ALLTOALL/ALLGATHER > with race conditions if #nprocs in one dimension is > only 1 or 2 and periodic==true > > The problem was reported as a bug of the OpenMPI library > by Simone Chiochetti from DICAM at the University of Trento, > but seems to be a bug in the MPI specification, > or at least an advice to implementors is missing. > > I produced a set of animated slides. > Please look at them in presentation mode with animation. > > Have fun with a problem that clearly prevents the use > of MPI_NEIGHBOR_... routines with cyclic boundary condition > if one wants to verify that mpirun -np 1 is doing > the same as the sequential code. > > Best regards > Rolf > > -- > Dr. Rolf Rabenseifner . . . . . . . . . .. email rabenseif...@hlrs.de . > High Performance Computing Center (HLRS) . phone ++49(0)711/685-65530 . > University of Stuttgart . . . . . . . . .. fax ++49(0)711 / 685-65832 . > Head of Dpmt Parallel Computing . . . www.hlrs.de/people/rabenseifner . > Nobelstr. 19, D-70550 Stuttgart, Germany . . . . (Office: Room 1.307) . > <neighbor_mpi-3_bug.pptx> > _______________________________________________ > mpi-forum mailing list > mpi-forum@lists.mpi-forum.org > https://lists.mpi-forum.org/mailman/listinfo/mpi-forum _______________________________________________ mpi-forum mailing list mpi-forum@lists.mpi-forum.org https://lists.mpi-forum.org/mailman/listinfo/mpi-forum
