Switching to default JLL-provided binary

[sloede]

As far as I can tell, MPIPreferences.use_jll_binary requires to manually specify the desired JLL binary to use. IIRC, setting JULIA_MPI_BINARY="" (to the empty string) automatically selected the default JLL binary. This was convenient if you just wanted to restore MPI.jl to "factory defaults". Would it be possible to bring this back, i.e., a MPIPreferences.use_jll_binary method without the binary argument that then selects the default depending on the OS?

[giordano]

MPI.jl/lib/MPIPreferences/src/MPIPreferences.jl

Line 65 in 8d36c1f

function use_jll_binary(binary = Sys.iswindows() ? "MicrosoftMPI_jll" : "MPICH_jll"; export_prefs=false, force=true)

It's already the case? Also, the docstring says

• "MicrosoftMPI_jll" (Only option and default on Winddows)
• "MPICH_jll" (Default on all other platform)

[sloede]

Ah, then I got confused by the docstring. Can we maybe change

MPI.jl/lib/MPIPreferences/src/MPIPreferences.jl

Line 53 in 8d36c1f

MPIPreferences.use_jll_binary(binary; export_prefs=false, force=true)

to something like

"""
    MPIPreferences.use_jll_binary([binary]; export_prefs=false, force=true)
...
"""

?

[giordano]

Sounds good with me