A fast non-reversible sampler for Bayesian finite mixture models

Fuente: arXiv
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Main Authors: Ascolani, Filippo, Zanella, Giacomo
Format: Preprint
Published: 2025
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author Ascolani, Filippo
Zanella, Giacomo
author_facet Ascolani, Filippo
Zanella, Giacomo
contents Finite mixtures are a cornerstone of Bayesian modelling, and it is well-known that sampling from the resulting posterior distribution can be a hard task. In particular, popular reversible Markov chain Monte Carlo schemes are often slow to converge when the number of observations $n$ is large. In this paper we introduce a novel and simple non-reversible sampling scheme for Bayesian finite mixture models, which is shown to drastically outperform classical samplers in many scenarios of interest, especially during convergence phase and when components in the mixture have non-negligible overlap. At the theoretical level, we show that the performance of the proposed non-reversible scheme cannot be worse than the standard one, in terms of asymptotic variance, by more than a factor of four; and we provide a scaling limit analysis suggesting that the non-reversible sampler can reduce the convergence time from O$(n^2)$ to O$(n)$. We also discuss why the statistical features of mixture models make them an ideal case for the use of non-reversible discrete samplers.
format Preprint
id arxiv_https___arxiv_org_abs_2510_03226
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A fast non-reversible sampler for Bayesian finite mixture models
Ascolani, Filippo
Zanella, Giacomo
Computation
Methodology
Machine Learning
Finite mixtures are a cornerstone of Bayesian modelling, and it is well-known that sampling from the resulting posterior distribution can be a hard task. In particular, popular reversible Markov chain Monte Carlo schemes are often slow to converge when the number of observations $n$ is large. In this paper we introduce a novel and simple non-reversible sampling scheme for Bayesian finite mixture models, which is shown to drastically outperform classical samplers in many scenarios of interest, especially during convergence phase and when components in the mixture have non-negligible overlap. At the theoretical level, we show that the performance of the proposed non-reversible scheme cannot be worse than the standard one, in terms of asymptotic variance, by more than a factor of four; and we provide a scaling limit analysis suggesting that the non-reversible sampler can reduce the convergence time from O$(n^2)$ to O$(n)$. We also discuss why the statistical features of mixture models make them an ideal case for the use of non-reversible discrete samplers.
title A fast non-reversible sampler for Bayesian finite mixture models
topic Computation
Methodology
Machine Learning
url https://arxiv.org/abs/2510.03226