Constrained Langevin Algorithms with L-mixing External Random Variables

Constrained Langevin Algorithms with L-mixing External Random Variables
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DOI:
10.48550/arxiv.2205.14192
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发表时间:
2022-05
期刊:
ArXiv
影响因子:
--
通讯作者:
Yu Zheng;Andrew G. Lamperski
Yu Zheng;Andrew G. Lamperski
中科院分区:
其他
文献类型:
--
作者:
Yu Zheng;Andrew G. Lamperski

文献摘要

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朗之万算法是一种增加了加性噪声的梯度下降方法,广泛用于马尔可夫链蒙特卡罗(MCMC)采样,优化和机器学习。近年来,非凸学习的Langevin算法的非渐近分析得到了广泛的研究。对于在具有IID数据变量的紧致凸域上具有非凸损失的约束问题,投影Langevin算法在$1$-Wasserstein距离中实现了$O(T^{-1/4}(\log T)^{1/2})$与其目标分布的偏差[27]。在本文中,我们得到了$O(T^{-1/2} \log T)$在$1$-Wasserstein距离的偏差为$L$-混合数据变量和多面体约束(不一定有界)的非凸损失。这改进了以前的约束问题的界限,并匹配最知名的无约束问题的界限。
Langevin algorithms are gradient descent methods augmented with additive noise, and are widely used in Markov Chain Monte Carlo (MCMC) sampling, optimization, and machine learning. In recent years, the non-asymptotic analysis of Langevin algorithms for non-convex learning has been extensively explored. For constrained problems with non-convex losses over a compact convex domain with IID data variables, the projected Langevin algorithm achieves a deviation of $O(T^{-1/4} (\log T)^{1/2})$ from its target distribution [27] in $1$-Wasserstein distance. In this paper, we obtain a deviation of $O(T^{-1/2} \log T)$ in $1$-Wasserstein distance for non-convex losses with $L$-mixing data variables and polyhedral constraints (which are not necessarily bounded). This improves on the previous bound for constrained problems and matches the best-known bound for unconstrained problems.