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COCOON
2009
Springer

A Polynomial-Time Perfect Sampler for the Q-Ising with a Vertex-Independent Noise

14 years 5 months ago
A Polynomial-Time Perfect Sampler for the Q-Ising with a Vertex-Independent Noise
We present a polynomial-time perfect sampler for the Q-Ising with a vertex-independent noise. The Q-Ising, one of the generalized models of the Ising, arose in the context of Bayesian image restoration in statistical mechanics. We study the distribution of Q-Ising on a two-dimensional square lattice over n vertices, that is, we deal with a discrete state space {1, . . . , Q}n for a positive integer Q. Employing the Q-Ising (having a parameter β) as a prior distribution, and assuming a Gaussian noise (having another parameter α), a posterior is obtained from the Bayes’ formula. Furthermore, we generalize it: the distribution of noise is not necessarily a Gaussian, but any vertex-independent noise. We first present a Gibbs sampler from our posterior, and also present a perfect sampler by defining a coupling via a monotone update function. Then, we show O(n log n) mixing time of the Gibbs sampler for the generalized model under a condition that β is sufficiently small (whatever th...
Masaki Yamamoto, Shuji Kijima, Yasuko Matsui
Added 26 May 2010
Updated 26 May 2010
Type Conference
Year 2009
Where COCOON
Authors Masaki Yamamoto, Shuji Kijima, Yasuko Matsui
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