Matryoshka Policy Gradient for Entropy-Regularized RL: Convergence and Global Optimality

Fuente: arXiv
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Main Authors: Ged, François, Veiga, Maria Han
Format: Preprint
Published: 2023
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author Ged, François
Veiga, Maria Han
author_facet Ged, François
Veiga, Maria Han
contents A novel Policy Gradient (PG) algorithm, called $\textit{Matryoshka Policy Gradient}$ (MPG), is introduced and studied, in the context of fixed-horizon max-entropy reinforcement learning, where an agent aims at maximizing entropy bonuses additional to its cumulative rewards. In the linear function approximation setting with softmax policies, we prove uniqueness and characterize the optimal policy of the entropy regularized objective, together with global convergence of MPG. These results are proved in the case of continuous state and action space. MPG is intuitive, theoretically sound and we furthermore show that the optimal policy of the infinite horizon max-entropy objective can be approximated arbitrarily well by the optimal policy of the MPG framework. Finally, we provide a criterion for global optimality when the policy is parametrized by a neural network in terms of the neural tangent kernel at convergence. As a proof of concept, we evaluate numerically MPG on standard test benchmarks.
format Preprint
id arxiv_https___arxiv_org_abs_2303_12785
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Matryoshka Policy Gradient for Entropy-Regularized RL: Convergence and Global Optimality
Ged, François
Veiga, Maria Han
Machine Learning
Artificial Intelligence
68T07
I.2.0; I.2.6
A novel Policy Gradient (PG) algorithm, called $\textit{Matryoshka Policy Gradient}$ (MPG), is introduced and studied, in the context of fixed-horizon max-entropy reinforcement learning, where an agent aims at maximizing entropy bonuses additional to its cumulative rewards. In the linear function approximation setting with softmax policies, we prove uniqueness and characterize the optimal policy of the entropy regularized objective, together with global convergence of MPG. These results are proved in the case of continuous state and action space. MPG is intuitive, theoretically sound and we furthermore show that the optimal policy of the infinite horizon max-entropy objective can be approximated arbitrarily well by the optimal policy of the MPG framework. Finally, we provide a criterion for global optimality when the policy is parametrized by a neural network in terms of the neural tangent kernel at convergence. As a proof of concept, we evaluate numerically MPG on standard test benchmarks.
title Matryoshka Policy Gradient for Entropy-Regularized RL: Convergence and Global Optimality
topic Machine Learning
Artificial Intelligence
68T07
I.2.0; I.2.6
url https://arxiv.org/abs/2303.12785