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U.S. Postal Service, Office of Inspector General, Arlington, Virginia 22209
We consider the problem of sampling a point from an arbitrary distribution
Department of Industrial and Systems Engineering, University of Washington, Seattle, Washington 98195
Department of Statistics, Chulalongkorn University, Bangkok 10330, Thailand
Clearsight Systems, Inc., Seattle, Washington 98104
Department of Industrial and Operations Engineering, University of Michigan, Ann Arbor, Michigan 48109
Department of Industrial and Systems Engineering, University of Washington, Seattle, Washington 98195
sbaumert{at}ameritech.net
archis{at}u.washington.edu
skiatsupaibul{at}hotmail.com
yanfang.shen{at}clearsightsystems.com
rlsmith{at}umich.edu
zelda{at}u.washington.edu
over an arbitrary subset S of an integer hyperrectangle. Neither the distribution
nor the support set S are assumed to be available as explicit mathematical equations, but may only be defined through oracles and, in particular, computer programs. This problem commonly occurs in black-box discrete optimization as well as counting and estimation problems. The generality of this setting and high dimensionality of S precludes the application of conventional random variable generation methods. As a result, we turn to Markov chain Monte Carlo (MCMC) sampling, where we execute an ergodic Markov chain that converges to
so that the distribution of the point delivered after sufficiently many steps can be made arbitrarily close to
. Unfortunately, classical Markov chains, such as the nearest-neighbor random walk or the coordinate direction random walk, fail to converge to
because they can get trapped in isolated regions of the support set. To surmount this difficulty, we propose discrete hit-and-run (DHR), a Markov chain motivated by the hit-and-run algorithm known to be the most efficient method for sampling from log-concave distributions over convex bodies in Rn. We prove that the limiting distribution of DHR is
as desired, thus enabling us to sample approximately from
by delivering the last iterate of a sufficiently large number of iterations of DHR. In addition to this asymptotic analysis, we investigate finite-time behavior of DHR and present a variety of examples where DHR exhibits polynomial performance.
Subject classifications: simulation; Markov chain Monte Carlo; probability; random walk.
History: Received December 2006;
revision received January 2008;
accepted January 2008.
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