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A Discrepancy Bound for a Deterministic Acceptance-Rejection Sampler

Abstract

We consider an acceptance-rejection sampler based on a deterministic driver sequence, which is a simple case of a Markov chain quasi-Monte Carlo (MCQMC) method. The deterministic sequence is chosen such that the discrepancy between the empirical proposal distribution and the proposal distribution is small. We use quasi-Monte Carlo (QMC) point sets for this purpose. We prove that the discrepancy of samples generated by the QMC acceptance-rejection sampler converges at a rate of N1/sN^{-1/s} for a given target density defined on [0,1]s1[0,1]^{s-1}. For some special cases we prove a convergence rate of NαN^{-\alpha}, where 1/sα<11/s \le \alpha < 1 depends on the target density. For a general density, whose domain is the real state space Rs1\mathbb{R}^{s-1}, the inverse Rosenblatt transformation can be used to convert samples from the (s1)(s-1)-dimensional cube to Rs1\mathbb{R}^{s-1}. We show that this transformation is measure preserving. This way, under certain conditions, we obtain the same convergence rate for a general target density defined in Rs1\mathbb{R}^{s-1}. Our numerical experiments show convergence rates beyond the plain Monte Carlo rate of N1/2N^{-1/2}.

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