This implements the random ray method for solving neutral particle transport problems. In particular, it solves a 2D problem using a multiple polar angle quadrature. Currently, only a single geometric input is supported, but adaptation to general Cartesian mesh problems is trivial.
Tramm, John R., Kord S. Smith, Benoit Forget, and Andrew R. Siegel. “The Random Ray Method for Neutral Particle Transport.” J. Comput. Phys. 342, no. C (August 2017): 229–252. https://doi.org/10.1016/j.jcp.2017.04.038.