  The most effective use of data from current and upcoming large scale
structure~(LSS) and CMB observations requires the ability to predict the
clustering of LSS with very high precision. The Effective Field Theory of Large
Scale Structure (EFTofLSS) provides an instrument for performing analytical
computations of LSS observables with the required precision in the mildly
nonlinear regime. In this paper, we develop efficient implementations of these
computations that allow for an exploration of their dependence on cosmological
parameters. They are based on two ideas. First, once an observable has been
computed with high precision for a reference cosmology, for a new cosmology the
same can be easily obtained with comparable precision just by adding the
difference in that observable, evaluated with much less precision. Second, most
cosmologies of interest are sufficiently close to the Planck best-fit cosmology
that observables can be obtained from a Taylor expansion around the reference
cosmology. These ideas are implemented for the matter power spectrum at two
loops and are released as public codes. When applied to cosmologies that are
within 3$\sigma$ of the Planck best-fit model, the first method evaluates the
power spectrum in a few minutes on a laptop, with results that have 1\% or
better precision, while with the Taylor expansion the same quantity is
instantly generated with similar precision. The ideas and codes we present may
easily be extended for other applications or higher-precision results.
