SkyNet is a general-purpose nuclear reaction network that was specifically designed for r-process nucleosynthesis calculations, but SkyNet is also applicable to other astrophysical scenarios.
SkyNet is written in C++ and highly modular. Besides a nuclear reaction network, SkyNet also includes a nuclear statistical equilibrium (NSE) solver, a Helmholtz equation of state (EOS), and the ability to make movies of abundance evolutions (see below). SkyNet is a self-heating network, which means it evolves the temperature by keeping track of entropy changes due to nuclear reactions and decays. SkyNet also has Python bindings, which make SkyNet very convenient to use from a Python script or interactive shell.
SkyNet is freely available as open source software at https://bitbucket.org/jlippuner/skynet.
This movie shows an r-process nucleosynthesis calculation with SkyNet, Ye (electron fraction) = 0.01, s (entropy) = 10 kB / baryon, tau (exponential density decay time scale) = 7.1 ms.
This movie shows the r-process in a neutron star-black hole merger.