Clus-UCB: A Near-Optimal Algorithm for Clustered Bandits

Fuente: arXiv
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Auteurs principaux: Gore, Aakash, Chaporkar, Prasanna
Format: Preprint
Publié: 2025
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author Gore, Aakash
Chaporkar, Prasanna
author_facet Gore, Aakash
Chaporkar, Prasanna
contents We study a stochastic multi-armed bandit setting where arms are partitioned into known clusters, such that the mean rewards of arms within a cluster differ by at most a known threshold. While the clustering structure is known a priori, the arm means are unknown. We derive an asymptotic lower bound on the regret that improves upon the classical bound of Lai & Robbins (1985). We then propose Clus-UCB, an efficient algorithm that closely matches this lower bound asymptotically. Clus-UCB is designed to exploit the clustering structure and introduces a new index to evaluate an arm, which depends on other arms within the cluster. In this way, arms share information among each other. We present simulation results of our algorithm and compare its performance against KL-UCB and other wellknown algorithms for bandits with dependent arms. Finally, we address some limitations of this work and conclude by mentioning some possible future research.
format Preprint
id arxiv_https___arxiv_org_abs_2508_02909
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Clus-UCB: A Near-Optimal Algorithm for Clustered Bandits
Gore, Aakash
Chaporkar, Prasanna
Machine Learning
We study a stochastic multi-armed bandit setting where arms are partitioned into known clusters, such that the mean rewards of arms within a cluster differ by at most a known threshold. While the clustering structure is known a priori, the arm means are unknown. We derive an asymptotic lower bound on the regret that improves upon the classical bound of Lai & Robbins (1985). We then propose Clus-UCB, an efficient algorithm that closely matches this lower bound asymptotically. Clus-UCB is designed to exploit the clustering structure and introduces a new index to evaluate an arm, which depends on other arms within the cluster. In this way, arms share information among each other. We present simulation results of our algorithm and compare its performance against KL-UCB and other wellknown algorithms for bandits with dependent arms. Finally, we address some limitations of this work and conclude by mentioning some possible future research.
title Clus-UCB: A Near-Optimal Algorithm for Clustered Bandits
topic Machine Learning
url https://arxiv.org/abs/2508.02909