# MPI interface for the Julia language

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This provides [Julia](http://julialang.org/) interface to the Message Passing Interface ([MPI](http://www.mpi-forum.org/)), roughly inspired by [mpi4py](https://github.com/mpi4py/mpi4py/).

Please see the [documentation](https://juliaparallel.github.io/MPI.jl/stable/) for instructions on [configuration](https://juliaparallel.github.io/MPI.jl/stable/configuration/) and [usage](https://juliaparallel.github.io/MPI.jl/stable/usage/).

**Breaking changes with v0.20:** The way how MPI.jl is configured to use
different MPI implementations has changed from v0.19 to v0.20 in a
*non-backward-compatible* manner.
Specifically, most `JULIA_MPI_XXX` variables do not have an effect anymore.
Please refer to the
[docs](https://juliaparallel.org/MPI.jl/stable/configuration/#Migration-from-MPI.jl-v0.19-or-earlier)
for information on how to migrate your existing configuration.

# Help and discussion

For help and discussion, we suggest asking on the following venues:
 - ["Julia at Scale" topic on the Julia Discourse](https://discourse.julialang.org/c/domain/parallel/34)
 - #distributed channel on the [Julia Slack](https://julialang.slack.com/) (visit [https://julialang.org/slack/](https://julialang.org/slack/) to join).

# Contributing

Contributions are encouraged. In particular, MPI provides several hundred functions, only a small number of which are currently exposed. If there are additional functions you would like to use, please open an [issue](https://github.com/JuliaParallel/MPI.jl/issues) or [pull request](https://github.com/JuliaParallel/MPI.jl/pulls).

Additional examples and documentation improvements are also very welcome.

# Citation

If you use MPI.jl in your work, please cite the following paper:

> Simon Byrne, Lucas C. Wilcox, and Valentin Churavy (2021) "MPI.jl: Julia bindings for the Message Passing Interface". _JuliaCon Proceedings_, 1(1), 68, doi: [10.21105/jcon.00068](https://doi.org/10.21105/jcon.00068)