We study the possibility of using multilevel algorithms for the computation
of correlation functions of gradient flow observables. For each point in the
correlation function an approximate flow is defined which depends only on links
in a subset of the lattice. Together with a local action this allows for
independent updates and consequently a convergence of the Monte Carlo process
faster than the inverse square root of the number of measurements. We
demonstrate the feasibility of this idea in the correlation functions of the
topological charge and the energy density.Comment: Minor modifications to the text. Version accepted to be published in
PRD. 18 pages, 5 figure