polymake is open source software for research in polyhedral geometry. It deals
with polytopes, polyhedra, and fans as well as simplicial complexes, matroids,
graphs, tropical hypersurfaces, and other objects. Supported platforms include
various flavors of Linux, FreeBSD, and Mac OS.
The documentation is available at polymake.org.
polymake is available via package manager for
various linux distributions.
You can also
install polymake from source. The installation
instructions for Mac can be found
here.
You can download the source code here. Alternatively you can find a read-only mirror (squashed) of the source code on github.