This paper presents results of first-principles density functional calculations of the equation of state (EOS) of PETN-I and P-HMX. The isotropic EOS for hydrostatic compression has been extended to include uniaxial compressions in the [100], [010], [001], [110], [101], [Oil], and [111] directions up to compression ratio VAAQ = 0.70. Equilibrium properties, including lattice parameters and elas...