  The evolution of scalar perturbations is studied for 2-component
(non-relativistic matter and dark energy) cosmological models at the linear and
non-linear stages. The dark energy is assumed to be the scalar field with
either classical or tachyonic Lagrangian and constant equation-of-state
parameter w. The fields and potentials were reconstructed for the set of
cosmological parameters derived from observations. The comparison of the
calculated within these models and experimental large-scale structure
characteristics is made. It is shown that for w=const such analysis can't
remove the existing degeneracy of the dark energy models.
