MuGen (moo-ghen, for Multivariate Genetics) is a C++ library that implements multivariate Bayesian hierarchical models, created and maintained by Tony Greenberg. While it was created with genetic applications in mind, it can be used in other fields as well. The latest version of the library can be found on this GitHub page. The library files to download are named MuGen.h and MuGen.cpp, as well as the GSLRIO.cpp which provides an R interface to save and read the binary data files generated with MuGen.