提出新框架BARBAT,让带对抗干扰的随机博弈更高效且接近最优。
A Near-optimal, Scalable and Parallelizable Framework for Stochastic Bandits Robust to Adversarial Corruptions and Beyond
- 设计新算法框架BARBAT,消除原方法中与臂数量相关的冗余开销
- 实现近似最优的后悔值,达到Ω(C)下界,比之前方法提升显著
- 适合多智能体、批量处理等场景,计算更轻量,易于并行
本文研究存在对抗性干扰的各类随机博弈问题。经典算法BARBAR虽具鲁棒性与效率,但其后悔值为O(KC),未达Ω(C)的理论下界,其中K为臂的数量,C为干扰水平。本文提出新框架BARBAT,通过消除K因子,实现近乎最优的后悔界(仅差对数因子)。该框架可扩展至多智能体、图结构、组合半-博弈及批量博弈等场景。相比基于正则化追随领袖(FTRL)的方法,本方法更易并行,尤其在半-博弈中计算成本更低。数值实验验证了其高效性。
原文摘要 · Abstract (English)
We investigate various stochastic bandit problems in the presence of adversarial corruptions. A seminal work for this problem is the BARBAR~\cite{gupta2019better} algorithm, which achieves both robustness and efficiency. However, it suffers from a regret of $O(KC)$, which does not match the lower bound of $Ω(C)$, where $K$ denotes the number of arms and $C$ denotes the corruption level. In this paper, we first improve the BARBAR algorithm by proposing a novel framework called BARBAT, which eliminates the factor of $K$ to achieve an optimal regret bound up to a logarithmic factor. We also extend BARBAT to various settings, including multi-agent bandits, graph bandits, combinatorial semi-bandits and batched bandits. Compared with the Follow-the-Regularized-Leader framework, our methods are more amenable to parallelization, making them suitable for multi-agent and batched bandit settings, and they incur lower computational costs, particularly in semi-bandit problems. Numerical experiments verify the efficiency of the proposed methods.
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