arXiv:2510.03798cs.LGstat.ML2025-10

提出适用于重尾奖励的分批多臂老虎机算法,发现尾部越重所需批次反而越少。

Batched Bandits with Heavy-Tailed Rewards

  • 设计鲁棒算法应对重尾奖励,适配多臂与Lipschitz场景
  • 重尾情况下,实例无关设置下批次数更少即可逼近最优后悔值
  • 实例相关设置中,批次数与尾部轻重无关,适合真实场景建模

分批多臂老虎机问题在临床试验等场景中至关重要。以往研究假设奖励分布为轻尾,但现实常呈现重尾特性。本文针对重尾奖励,提出多臂与Lipschitz设置下的鲁棒分批算法。研究发现令人意外:在实例无关设置及Lipschitz设置中,尾部越重,实现近似最优后悔值所需的批次数反而越少;而在实例相关设置中,达到近似最优后悔值所需的批次数不随尾部轻重变化。

原文摘要 · Abstract (English)

The batched multi-armed bandit (MAB) problem, where rewards are collected in batches, is pivotal in applications like clinical trials. While prior work assumes light-tailed reward distributions, real-world scenarios often exhibit heavy-tailed outcomes. This paper addresses this gap by introducing robust batched bandit algorithms for heavy-tailed rewards in both multi-arm and Lipschitz settings. We uncover somewhat surprising phenomena for such problems -- heavier tails require fewer batches to achieve near-optimal regret in the instance-independent setting, as well as the Lipschitz setting. In sharp contrast, in the instance-dependent setting, the number of batches required to achieve near-optimal regret does not depend on the tail heaviness.

强化学习带尾分布分批学习多臂老虎机

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