sci@gentoo.org Gentoo Science Project O2scl is a C++ class library for object-oriented numerical programming. It includes classes based on numerical routines from GSL and CERNLIB and two sub-libraries: thermodynamics of ideal and nearly-ideal particles with quantum statistics and e quations of state for finite density relevant for neutron stars. Build matrix manipulation with sci-libs/armadillo Build matrix manipulation with dev-cpp/eigen awsteiner/o2scl