# 4.2. Downloading Open MPI

Open MPI is generally available two ways:

1. As source code.

   - The best place to get an official Open MPI source code distribution is from the main Open MPI web site.

   - Downstream Open MPI packagers (e.g., Linux distributions) sometimes also provide source code distributions. They may include additional patches or modifications.

     Consult your favorite downstream packager for more details.

   Caution

   Do not download an Open MPI source code tarball from GitHub.com. The tarballs automatically generated by GitHub.com are incomplete and will not build properly.

   GitHub.com-generated tarballs are not official Open MPI releases.

2. As binary packages.

   - The Open MPI community does not provide binary packages on the main Open MPI web site.

   - Various downstream packagers (e.g., Linux distributions, Homebrew, MacPorts, etc.) do provide pre-built, binary packages for Open MPI.

     Consult your favorite downstream packager for more details.

The majority of the rest of this section deals with installing Open MPI from source.