Complexity of Non-Log-Concave Sampling in Fisher Information

Fuente: arXiv
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Main Authors: Chewi, Sinho, Wibisono, Andre
Format: Preprint
Published: 2026
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author Chewi, Sinho
Wibisono, Andre
author_facet Chewi, Sinho
Wibisono, Andre
contents We study the query complexity of obtaining a relative Fisher information guarantee for sampling from a log-smooth non-log-concave distribution; this is a sampling analog of finding an approximate stationary point in optimization. Our algorithm is based on the proximal sampler, which is an implicit discretization of the Langevin diffusion, and requires an implementation of the backward step known as the restricted Gaussian oracle (RGO). We show that by leveraging the recent results for log-concave sampling with high-accuracy guarantees in Rényi divergence, we can obtain an approximate RGO implementation that -- when used with the proximal sampler -- yields a complexity guarantee in relative Fisher information that inherits the same dimension dependence as log-concave sampling, and improves upon prior work for non-log-concave sampling. We also show a converse reduction that any improvement in the dimension dependence in relative Fisher information for non-log-concave sampling will yield an improved dimension dependence for high-accuracy log-concave sampling.
format Preprint
id arxiv_https___arxiv_org_abs_2605_15859
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Complexity of Non-Log-Concave Sampling in Fisher Information
Chewi, Sinho
Wibisono, Andre
Data Structures and Algorithms
Machine Learning
Statistics Theory
We study the query complexity of obtaining a relative Fisher information guarantee for sampling from a log-smooth non-log-concave distribution; this is a sampling analog of finding an approximate stationary point in optimization. Our algorithm is based on the proximal sampler, which is an implicit discretization of the Langevin diffusion, and requires an implementation of the backward step known as the restricted Gaussian oracle (RGO). We show that by leveraging the recent results for log-concave sampling with high-accuracy guarantees in Rényi divergence, we can obtain an approximate RGO implementation that -- when used with the proximal sampler -- yields a complexity guarantee in relative Fisher information that inherits the same dimension dependence as log-concave sampling, and improves upon prior work for non-log-concave sampling. We also show a converse reduction that any improvement in the dimension dependence in relative Fisher information for non-log-concave sampling will yield an improved dimension dependence for high-accuracy log-concave sampling.
title Complexity of Non-Log-Concave Sampling in Fisher Information
topic Data Structures and Algorithms
Machine Learning
Statistics Theory
url https://arxiv.org/abs/2605.15859