Spectral Gap of Metropolis Algorithms for Non-smooth Distributions under Isoperimetry

Fuente: arXiv
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Main Authors: Liu, Shuigen, Tong, Xin T.
Format: Preprint
Published: 2026
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_version_ 1866917397535916032
author Liu, Shuigen
Tong, Xin T.
author_facet Liu, Shuigen
Tong, Xin T.
contents Metropolis algorithms are classical tools for sampling from target distributions, with broad applications in statistics and scientific computing. Their convergence speed is governed by the spectral gap of the associated Markov operator. Recently, Andrieu et al. (2024) derived the first explicit bounds for the spectral gap of Random--Walk Metropolis when the target distribution is smooth and strongly log-concave. However, existing literature rarely discusses non-smooth targets. In this work, we derive explicit spectral gap bounds for the random-walk Metropolis and Metropolis--adjusted Langevin algorithms over a broad class of non-smooth distributions. Moreover, combining our analysis with a recent result in Goyal et al. (2025), we extend these bounds to targets satisfying a Poincare or log-Sobolev inequality, beyond the strongly log-concave setting. Our theoretical results are further supported by numerical experiments.
format Preprint
id arxiv_https___arxiv_org_abs_2601_21763
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Spectral Gap of Metropolis Algorithms for Non-smooth Distributions under Isoperimetry
Liu, Shuigen
Tong, Xin T.
Probability
Computation
65C05, 65C40, 60J22
Metropolis algorithms are classical tools for sampling from target distributions, with broad applications in statistics and scientific computing. Their convergence speed is governed by the spectral gap of the associated Markov operator. Recently, Andrieu et al. (2024) derived the first explicit bounds for the spectral gap of Random--Walk Metropolis when the target distribution is smooth and strongly log-concave. However, existing literature rarely discusses non-smooth targets. In this work, we derive explicit spectral gap bounds for the random-walk Metropolis and Metropolis--adjusted Langevin algorithms over a broad class of non-smooth distributions. Moreover, combining our analysis with a recent result in Goyal et al. (2025), we extend these bounds to targets satisfying a Poincare or log-Sobolev inequality, beyond the strongly log-concave setting. Our theoretical results are further supported by numerical experiments.
title Spectral Gap of Metropolis Algorithms for Non-smooth Distributions under Isoperimetry
topic Probability
Computation
65C05, 65C40, 60J22
url https://arxiv.org/abs/2601.21763