Adversarial Bandits against Arbitrary Strategies

Fuente: arXiv
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Autores principales: Kim, Jung-hun, Yun, Se-Young
Formato: Preprint
Publicado: 2022
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author Kim, Jung-hun
Yun, Se-Young
author_facet Kim, Jung-hun
Yun, Se-Young
contents We study the adversarial bandit problem against arbitrary strategies, where the difficulty is captured by an unknown parameter $S$, which is the number of switches in the best arm in hindsight. To handle this problem, we adopt the master-base framework using the online mirror descent method (OMD). We first provide a master-base algorithm with simple OMD, achieving $\tilde{O}(S^{1/2}K^{1/3}T^{2/3})$, in which $T^{2/3}$ comes from the variance of loss estimators. To mitigate the impact of the variance, we propose using adaptive learning rates for OMD and achieve $\tilde{O}(\min\{\sqrt{SKTρ},S\sqrt{KT}\})$, where $ρ$ is a variance term for loss estimators.
format Preprint
id arxiv_https___arxiv_org_abs_2205_14839
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Adversarial Bandits against Arbitrary Strategies
Kim, Jung-hun
Yun, Se-Young
Machine Learning
We study the adversarial bandit problem against arbitrary strategies, where the difficulty is captured by an unknown parameter $S$, which is the number of switches in the best arm in hindsight. To handle this problem, we adopt the master-base framework using the online mirror descent method (OMD). We first provide a master-base algorithm with simple OMD, achieving $\tilde{O}(S^{1/2}K^{1/3}T^{2/3})$, in which $T^{2/3}$ comes from the variance of loss estimators. To mitigate the impact of the variance, we propose using adaptive learning rates for OMD and achieve $\tilde{O}(\min\{\sqrt{SKTρ},S\sqrt{KT}\})$, where $ρ$ is a variance term for loss estimators.
title Adversarial Bandits against Arbitrary Strategies
topic Machine Learning
url https://arxiv.org/abs/2205.14839