Offline Reinforcement Learning with Closed-Form Policy Improvement Operators
Offline Reinforcement Learning with Closed-Form Policy Improvement Operators
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DOI:
10.48550/arxiv.2211.15956
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发表时间:
2022-11
期刊:
影响因子:
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通讯作者:
Jiachen Li;Edwin Zhang;Ming Yin;Qinxun Bai;Yu-Xiang Wang;William Yang Wang
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文献类型:
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作者:
Jiachen Li;Edwin Zhang;Ming Yin;Qinxun Bai;Yu-Xiang Wang;William Yang Wang
Behavior constrained policy optimization has been demonstrated to be a successful paradigm for tackling Offline Reinforcement Learning. By exploiting historical transitions, a policy is trained to maximize a learned value function while constrained by the behavior policy to avoid a significant distributional shift. In this paper, we propose our closed-form policy improvement operators. We make a novel observation that the behavior constraint naturally motivates the use of first-order Taylor approximation, leading to a linear approximation of the policy objective. Additionally, as practical datasets are usually collected by heterogeneous policies, we model the behavior policies as a Gaussian Mixture and overcome the induced optimization difficulties by leveraging the LogSumExp's lower bound and Jensen's Inequality, giving rise to a closed-form policy improvement operator. We instantiate offline RL algorithms with our novel policy improvement operators and empirically demonstrate their effectiveness over state-of-the-art algorithms on the standard D4RL benchmark. Our code is available at https://cfpi-icml23.github.io/.