The Performance Of The Unadjusted Langevin Algorithm Without Smoothness Assumptions

Fuente: arXiv
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Autori principali: Johnston, Tim, Lytras, Iosif, Makras, Nikolaos, Sabanis, Sotirios
Natura: Preprint
Pubblicazione: 2025
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author Johnston, Tim
Lytras, Iosif
Makras, Nikolaos
Sabanis, Sotirios
author_facet Johnston, Tim
Lytras, Iosif
Makras, Nikolaos
Sabanis, Sotirios
contents In this article, we study the problem of sampling from distributions whose densities are not necessarily smooth nor logconcave. We propose a simple Langevin-based algorithm that does not rely on popular but computationally challenging techniques, such as the Moreau-Yosida envelope or Gaussian smoothing, and show consequently that the performance of samplers like ULA does not necessarily degenerate arbitrarily with low regularity. In particular, we show that the Lipschitz or Hölder continuity assumption can be replaced by a geometric one-sided Lipschitz condition that allows even for discontinuous log-gradients. We derive non-asymptotic guarantees for the convergence of the algorithm to the target distribution in Wasserstein distances. Non-asymptotic bounds are also provided for the performance of the algorithm as an optimizer, specifically for the solution of associated excess risk optimization problems.
format Preprint
id arxiv_https___arxiv_org_abs_2502_03458
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Performance Of The Unadjusted Langevin Algorithm Without Smoothness Assumptions
Johnston, Tim
Lytras, Iosif
Makras, Nikolaos
Sabanis, Sotirios
Machine Learning
Optimization and Control
Probability
Computation
In this article, we study the problem of sampling from distributions whose densities are not necessarily smooth nor logconcave. We propose a simple Langevin-based algorithm that does not rely on popular but computationally challenging techniques, such as the Moreau-Yosida envelope or Gaussian smoothing, and show consequently that the performance of samplers like ULA does not necessarily degenerate arbitrarily with low regularity. In particular, we show that the Lipschitz or Hölder continuity assumption can be replaced by a geometric one-sided Lipschitz condition that allows even for discontinuous log-gradients. We derive non-asymptotic guarantees for the convergence of the algorithm to the target distribution in Wasserstein distances. Non-asymptotic bounds are also provided for the performance of the algorithm as an optimizer, specifically for the solution of associated excess risk optimization problems.
title The Performance Of The Unadjusted Langevin Algorithm Without Smoothness Assumptions
topic Machine Learning
Optimization and Control
Probability
Computation
url https://arxiv.org/abs/2502.03458