I don't understand why you need so many tags. Is the communication pattern actually MPI_Alltoallv, but you implemented it in MPI_Send/Recv?
--Junchao Zhang On Mon, Nov 21, 2022 at 2:37 PM Matthew Knepley <knep...@gmail.com> wrote: > In data_ex.c, Swarm uses a distinct tag for each pair of processes. If the > number of processes exceeds 1024, there are > 1024^2 tags which exceeds > MPI_TAG_UB on Intel MPI. > > My solution is going to be to use that process pair number modulo > MPI_TAG_UB. Does anyone have a slicker suggestion? > > Thanks, > > Matt > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > > https://www.cse.buffalo.edu/~knepley/ > <http://www.cse.buffalo.edu/~knepley/> >