  The recent introduction of machine learning techniques, especially
normalizing flows, for the sampling of lattice gauge theories has shed some
hope on improving the sampling efficiency of the traditional HMC algorithm.
Naive use of normalizing flows has been shown to lead to bad scaling with the
volume. In this talk we propose using local normalizing flows at a scale given
by the correlation length. Even if naively these transformations have a small
acceptance, when combined with the HMC algorithm lead to algorithms with high
acceptance, and also with reduced autocorrelation times compared with HMC.
Several scaling tests are performed in the $\phi^{4}$ theory in 2D.
