Efficient and Interpretable Bandit Algorithms

Fuente: arXiv
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Autores principales: Mukherjee, Subhojyoti, Zhu, Ruihao, Kveton, Branislav
Formato: Preprint
Publicado: 2023
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author Mukherjee, Subhojyoti
Zhu, Ruihao
Kveton, Branislav
author_facet Mukherjee, Subhojyoti
Zhu, Ruihao
Kveton, Branislav
contents Motivated by the importance of explainability in modern machine learning, we design bandit algorithms that are efficient and interpretable. A bandit algorithm is interpretable if it explores with the objective of reducing uncertainty in the unknown model parameter. To quantify the interpretability, we introduce a novel metric of model error, which compares the rate reduction of the mean reward estimates to their actual means among all the plausible actions. We propose CODE, a bandit algorithm based on a Constrained Optimal DEsign, that is interpretable and maximally reduces the uncertainty. The key idea in CODE is to explore among all plausible actions, determined by a statistical constraint, to achieve interpretability. We implement CODE efficiently in both multi-armed and linear bandits and derive near-optimal regret bounds by leveraging the optimality criteria of the approximate optimal design. CODE can be also viewed as removing phases in conventional phased elimination, which makes it more practical and general. We demonstrate the advantage of CODE by numerical experiments on both synthetic and real-world problems. CODE outperforms other state-of-the-art interpretable designs while matching the performance of popular but uninterpretable designs, such as upper confidence bound algorithms.
format Preprint
id arxiv_https___arxiv_org_abs_2310_14751
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Efficient and Interpretable Bandit Algorithms
Mukherjee, Subhojyoti
Zhu, Ruihao
Kveton, Branislav
Machine Learning
Motivated by the importance of explainability in modern machine learning, we design bandit algorithms that are efficient and interpretable. A bandit algorithm is interpretable if it explores with the objective of reducing uncertainty in the unknown model parameter. To quantify the interpretability, we introduce a novel metric of model error, which compares the rate reduction of the mean reward estimates to their actual means among all the plausible actions. We propose CODE, a bandit algorithm based on a Constrained Optimal DEsign, that is interpretable and maximally reduces the uncertainty. The key idea in CODE is to explore among all plausible actions, determined by a statistical constraint, to achieve interpretability. We implement CODE efficiently in both multi-armed and linear bandits and derive near-optimal regret bounds by leveraging the optimality criteria of the approximate optimal design. CODE can be also viewed as removing phases in conventional phased elimination, which makes it more practical and general. We demonstrate the advantage of CODE by numerical experiments on both synthetic and real-world problems. CODE outperforms other state-of-the-art interpretable designs while matching the performance of popular but uninterpretable designs, such as upper confidence bound algorithms.
title Efficient and Interpretable Bandit Algorithms
topic Machine Learning
url https://arxiv.org/abs/2310.14751