Models of stellar events usually require the relationship between various thermodynamic properties over a large span of
temperatures, densities, and compositions. Stellar equation of state (henceforth EOS) routines are used for the thermodynamic
conditions found in models of stellar evolution, supernovae, novae, and X-ray bursts, so the EOS must be accurate in
regions where the electrons and positrons have a speed arbitrarily close to the causal limits and an arbitrary degree of
degeneracy. With over 109 calls to the EOS being common in two- and three-dimensional hydrodynamic models of stellar
phenomena, it is very desirable to have an electron-positron EOS that is as efficient as possible and yet accurately represents
the relevant physics.