Tight Sampling Complexity with stochastic gradient oracles in Fixed Dimensions
- URL: http://arxiv.org/abs/2609.12590v1
- Date: Fri, 11 Sep 2026 08:44:06 GMT
- Title: Tight Sampling Complexity with stochastic gradient oracles in Fixed Dimensions
- Abstract summary: The potential is $$-strongly convex and $L$-smooth, with an unknown mode in the ball of radius $-1/2$ about the origin.<n>We prove that the tight complexity of sampling a distribution within $$-TV distance from the target distribution is [ Nstar_textTV=!left(log(1+)+ frac2right), ] where $:=frac L$ is the condition number.
- Score: 5.603202398374589
- License: http://creativecommons.org/licenses/by/4.0/
- 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 $σ^2$. For every $σ^2\ge0$ and total variation (TV) accuracy $0<\varepsilon\le1/10$, we prove that the tight complexity of sampling a distribution within $ε$-TV distance from the target distribution is \[ N^\star_{\text{TV}}=Θ\!\left(\log(1+κ)+ \frac{σ^2}{με}\right), \] where $κ:=\frac Lμ$ 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^\star_{\text{TV}}=Θ\!\left(\log(1+κ)\right)$.
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