Augmented Bayesian Policy Search

Fuente: arXiv
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Main Authors: Kallel, Mahdi, Basu, Debabrota, Akrour, Riad, D'Eramo, Carlo
Format: Preprint
Published: 2024
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author Kallel, Mahdi
Basu, Debabrota
Akrour, Riad
D'Eramo, Carlo
author_facet Kallel, Mahdi
Basu, Debabrota
Akrour, Riad
D'Eramo, Carlo
contents Deterministic policies are often preferred over stochastic ones when implemented on physical systems. They can prevent erratic and harmful behaviors while being easier to implement and interpret. However, in practice, exploration is largely performed by stochastic policies. First-order Bayesian Optimization (BO) methods offer a principled way of performing exploration using deterministic policies. This is done through a learned probabilistic model of the objective function and its gradient. Nonetheless, such approaches treat policy search as a black-box problem, and thus, neglect the reinforcement learning nature of the problem. In this work, we leverage the performance difference lemma to introduce a novel mean function for the probabilistic model. This results in augmenting BO methods with the action-value function. Hence, we call our method Augmented Bayesian Search~(ABS). Interestingly, this new mean function enhances the posterior gradient with the deterministic policy gradient, effectively bridging the gap between BO and policy gradient methods. The resulting algorithm combines the convenience of the direct policy search with the scalability of reinforcement learning. We validate ABS on high-dimensional locomotion problems and demonstrate competitive performance compared to existing direct policy search schemes.
format Preprint
id arxiv_https___arxiv_org_abs_2407_04864
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Augmented Bayesian Policy Search
Kallel, Mahdi
Basu, Debabrota
Akrour, Riad
D'Eramo, Carlo
Machine Learning
Deterministic policies are often preferred over stochastic ones when implemented on physical systems. They can prevent erratic and harmful behaviors while being easier to implement and interpret. However, in practice, exploration is largely performed by stochastic policies. First-order Bayesian Optimization (BO) methods offer a principled way of performing exploration using deterministic policies. This is done through a learned probabilistic model of the objective function and its gradient. Nonetheless, such approaches treat policy search as a black-box problem, and thus, neglect the reinforcement learning nature of the problem. In this work, we leverage the performance difference lemma to introduce a novel mean function for the probabilistic model. This results in augmenting BO methods with the action-value function. Hence, we call our method Augmented Bayesian Search~(ABS). Interestingly, this new mean function enhances the posterior gradient with the deterministic policy gradient, effectively bridging the gap between BO and policy gradient methods. The resulting algorithm combines the convenience of the direct policy search with the scalability of reinforcement learning. We validate ABS on high-dimensional locomotion problems and demonstrate competitive performance compared to existing direct policy search schemes.
title Augmented Bayesian Policy Search
topic Machine Learning
url https://arxiv.org/abs/2407.04864