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By default, MPI.jl will download and link against an own MPICH implementation. On the HLRN-IV systems, we advise using the Intel MPI implementation, as we have found some serious problems with the Open MPI implementation in conjunction with multithreading.
Therefore the julia Julia module set already some environment variables under the assumption that the impi/2018.5 module is used (both for MPI versions 0.19 or earlier and for the newer versions using the MPIPreferences system).
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$ module load impi/2018.5
$ module load julia
$ julia -e 'using Pkg; Pkg.add("MPIPreferences")'
$; juliausing -e 'using PkgMPIPreferences; MPIPreferences.use_system_binary(); Pkg.add("MPI")'
You can test the the correct version is used via
$ julia -e 'using MPI; println(MPI.MPI_LIBRARY_VERSION_STRING)'
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There is no direct dependency to impi/2018.5 in juliaJulia's module file, so if needed it is still possible to adjust the environment to a different configuration before building and loading the MPI module.jl package. Please check to the MPI.jl documentation for details.
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