How do I use Plots with MPIClusterManagers in "only workers" mode?

Specific Domains Julia at Scale
1

I find that @mpi_do from MPIClusterManagers.jl is great with Jupiter notebooks. However, I’m not able to plot anything from within @mpi_do:

using MPIClusterManagers
using Distributed
manager = MPIManager(np = 4)
addprocs(manager)

@mpi_do manager begin
    using MPI
    using Plots

    comm = MPI.COMM_WORLD
    rank = MPI.Comm_rank(comm)

    data = 1
    G = MPI.Gather(data, 0, comm)
    if rank == 0
        plot(G)
    end
end

I suspect this is related to this issue, but I’m not sure. Any workaround?

2

At the moment, your best option for now is to do the plotting on the main process (pid 1). Something like this should work:

G = remotecall_fetch(eval, 2, :G) # pid 2 == MPI rank 0
plot(G)

I’m trying to build some tools that will make this sort of thing easier: https://github.com/simonbyrne/SPMD.jl

3

Thanks, Simon. And that package is great!

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