Rate-optimal Design for Anytime Best Arm Identification

Fuente: arXiv
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Main Authors: Komiyama, Junpei, Jang, Kyoungseok, Honda, Junya
Format: Preprint
Published: 2025
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author Komiyama, Junpei
Jang, Kyoungseok
Honda, Junya
author_facet Komiyama, Junpei
Jang, Kyoungseok
Honda, Junya
contents We consider the best arm identification problem, where the goal is to identify the arm with the highest mean reward from a set of $K$ arms under a limited sampling budget. This problem models many practical scenarios such as A/B testing. We consider a class of algorithms for this problem, which is provably minimax optimal up to a constant factor. This idea is a generalization of existing works in fixed-budget best arm identification, which are limited to a particular choice of risk measures. Based on the framework, we propose Almost Tracking, a closed-form algorithm that has a provable guarantee on the popular risk measure $H_1$. Unlike existing algorithms, Almost Tracking does not require the total budget in advance nor does it need to discard a significant part of samples, which gives a practical advantage. Through experiments on synthetic and real-world datasets, we show that our algorithm outperforms existing anytime algorithms as well as fixed-budget algorithms.
format Preprint
id arxiv_https___arxiv_org_abs_2510_23199
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Rate-optimal Design for Anytime Best Arm Identification
Komiyama, Junpei
Jang, Kyoungseok
Honda, Junya
Machine Learning
We consider the best arm identification problem, where the goal is to identify the arm with the highest mean reward from a set of $K$ arms under a limited sampling budget. This problem models many practical scenarios such as A/B testing. We consider a class of algorithms for this problem, which is provably minimax optimal up to a constant factor. This idea is a generalization of existing works in fixed-budget best arm identification, which are limited to a particular choice of risk measures. Based on the framework, we propose Almost Tracking, a closed-form algorithm that has a provable guarantee on the popular risk measure $H_1$. Unlike existing algorithms, Almost Tracking does not require the total budget in advance nor does it need to discard a significant part of samples, which gives a practical advantage. Through experiments on synthetic and real-world datasets, we show that our algorithm outperforms existing anytime algorithms as well as fixed-budget algorithms.
title Rate-optimal Design for Anytime Best Arm Identification
topic Machine Learning
url https://arxiv.org/abs/2510.23199