  We present a new numerical scheme to treat the non-linear evolution of
cosmological power spectra. Governing equations for matter power spectra have
been previously derived by a non-perturbative technique with closure
approximation. Solutions of the resultant closure equations just correspond to
the resummation of an infinite class of perturbation corrections, and they
consistently reproduce the one-loop results of standard perturbation theory. We
develop a numerical algorithm to solve closure evolutions in both perturbative
and non-perturbative regimes. The present numerical scheme is particularly
suited for examining non-linear matter power spectrum in general cosmological
models, including modified theory of gravity. As a demonstration, we study
weakly non-linear evolution of power spectrum in a class of modified gravity
models, as well as various dark energy models.
