We present a non-homogeneous Hastings-Metropolis algorithm for which the pr
oposal density approximates the target density, as the number of iterations
increases. The proposal at the n-th step is a non-parametric estimate of t
he density of the algorithm, and uses an increasing number of i.i.d. copies
of the Markov chain. The resulting algorithm converges (in n) geometricall
y faster than a Hastings-Metropolis algorithm with an arbitrary proposal. (
C) Academie des Sciences/Elsevier, Paris.