Poster
Efficient Informed Proposals for Discrete Distributions via Newton’s Series Approximation
Yue Xiang · Dongyao Zhu · Bowen Lei · Dongkuan Xu · Ruqi Zhang
Auditorium 1 Foyer 143
Gradients have been exploited in recent studies in proposal distributions to accelerate the convergence of Markov chain Monte Carlo algorithms on discrete distributions. However, these methods require a natural differentiable extension of the target discrete distribution, which often does not exist or does not provide an effective guidance of the gradient. In this paper, we develop a gradient-like proposal for any discrete distribution without the requirement of a natural differentiable extension. Built upon a locally-balanced proposal, our method efficiently approximates the discrete likelihood ratio via a Newton's series expansion, as a discrete analog of the continuous Taylor series expansion, to enable a large and efficient exploration in discrete spaces. We show that our method can also be viewed as a multilinear extension, thus inheriting the desired properties. We prove that our method has a guaranteed convergence rate with or without the Metropolis-Hastings step. Furthermore, our method outperforms a number of popular alternatives in several different experiments, including the Ising model, the facility location problem, text summarization, and image retrieval.
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