Tight Sampling Complexity with Stochastic Gradient Oracles in Fixed Dimensions

arXiv:2609.12590 · math.ST, cs.LG, math.PR, stat.TH · Submitted 2026-09-11 · Read on arXiv

math.ST, cs.LG, math.PR, stat.TH

Submitted: 2026-09-11

Updated: 2026-09-26

Comments: 55 pages

License: http://creativecommons.org/licenses/by/4.0/

The gist: We investigate the stochastic-gradient query complexity of sampling smooth strongly log-concave distributions in any fixed Euclidean dimension.

Terminology

Abstract

We investigate the stochastic-gradient query complexity of sampling smooth strongly log-concave distributions in any fixed Euclidean dimension. The potential is μ-strongly convex and L-smooth, with an unknown mode in the ball of radius μ-1/2 about the origin. We have access to unbiased stochastic oracles with the variance at most σ squared. For every σ 2 0 and total variation (TV) accuracy 0< epsilon 1/10, we prove that the tight complexity of sampling a distribution within ε-TV distance from the target distribution is [ N TV=Θ! ((1+κ)+ σ squared over με),] where κ:= Lμ is the condition number. Note that this complexity bound is simultaneously tight for the condition number κ and accuracy ε. Besides, our tight complexity bound is adaptive to noiseless setting σ=0, which is N TV=Θ! ((1+κ)).

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