In-Medium Similarity Renormalization Group software for nuclear structure calculations. Written in C++, with Python bindings. It is capapble of performing Hartree-Fock, single-reference IM-SRG, and valence-space IM-SRG calculations. If you don't know what these things are, you should check out http://link.aps.org/doi/10.1103/PhysRevLett.106.222502 http://www.sciencedirect.com/science/article/pii/S0370157315005414
The IMSRG code in the src directory is copyrighted under the GNU Public License (http://www.gnu.org/licenses/gpl.html). This code also uses the Armadillo library, which is covered under the Mozilla Public License (https://www.mozilla.org/en-US/MPL/2.0/), and the BOOST library, which is covered under the BOOST Software License (http://www.boost.org/users/license.html)