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Related papers: SARC: Soft Actor Retrospective Critic

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Although Reinforcement Learning (RL) is effective for sequential decision-making problems under uncertainty, it still fails to thrive in real-world systems where risk or safety is a binding constraint. In this paper, we formulate the RL…

Machine Learning · Computer Science 2022-07-07 Yannis Flet-Berliac , Debabrota Basu

Actor-critic methods solve reinforcement learning problems by updating a parameterized policy known as an actor in a direction that increases an estimate of the expected return known as a critic. However, existing actor-critic methods only…

Machine Learning · Statistics 2018-02-23 Voot Tangkaratt , Abbas Abdolmaleki , Masashi Sugiyama

Reinforcement learning, mathematically described by Markov Decision Problems, may be approached either through dynamic programming or policy search. Actor-critic algorithms combine the merits of both approaches by alternating between steps…

Machine Learning · Computer Science 2023-01-31 Harshat Kumar , Alec Koppel , Alejandro Ribeiro

Despite definite success in deep reinforcement learning problems, actor-critic algorithms are still confronted with sample inefficiency in complex environments, particularly in tasks where efficient exploration is a bottleneck. These…

Machine Learning · Computer Science 2021-02-09 Yannis Flet-Berliac , Johan Ferret , Olivier Pietquin , Philippe Preux , Matthieu Geist

The performance of deep reinforcement learning methods prone to degenerate when applied to environments with non-stationary dynamics. In this paper, we utilize the latent context recurrent encoders motivated by recent Meta-RL materials, and…

Machine Learning · Computer Science 2021-05-11 Yuan Pu , Shaochen Wang , Xin Yao , Bin Li

Actor-Critic based approaches were among the first to address reinforcement learning in a general setting. Recently, these algorithms have gained renewed interest due to their generality, good convergence properties, and possible biological…

Machine Learning · Computer Science 2009-09-17 D. Di Castro , R. Meir

This work extends an established critic match loss landscape visualization method from online to off-policy reinforcement learning (RL), aiming to reveal the optimization geometry behind critic learning. Off-policy RL differs from stepwise…

Machine Learning · Computer Science 2026-03-17 Jingyi Liu , Jian Guo , Eberhard Gill

Soft Actor-Critic (SAC) is an off-policy actor-critic deep reinforcement learning (DRL) algorithm based on maximum entropy reinforcement learning. By combining off-policy updates with an actor-critic formulation, SAC achieves…

Machine Learning · Computer Science 2019-06-11 Che Wang , Keith Ross

We revisit the standard formulation of tabular actor-critic algorithm as a two time-scale stochastic approximation with value function computed on a faster time-scale and policy computed on a slower time-scale. This emulates policy…

Machine Learning · Computer Science 2024-06-21 Shalabh Bhatnagar , Vivek S. Borkar , Soumyajit Guin

As an important type of reinforcement learning algorithms, actor-critic (AC) and natural actor-critic (NAC) algorithms are often executed in two ways for finding optimal policies. In the first nested-loop design, actor's one update of…

Machine Learning · Computer Science 2020-05-11 Tengyu Xu , Zhe Wang , Yingbin Liang

The actor-critic (AC) algorithm is a popular method to find an optimal policy in reinforcement learning. In the infinite horizon scenario, the finite-sample convergence rate for the AC and natural actor-critic (NAC) algorithms has been…

Machine Learning · Computer Science 2021-02-15 Tengyu Xu , Zhe Wang , Yingbin Liang

While Soft Actor-Critic (SAC) is highly effective in continuous control, its discrete counterpart (DSAC) performs poorly on challenging discrete-action domains such as Atari. Consequently, starting from DSAC, we revisit the design of…

Machine Learning · Computer Science 2026-05-13 Reza Asad , Reza Babanezhad , Sharan Vaswani

We investigate the neural Actor Critic algorithm using shallow neural networks for both the Actor and Critic models. The focus of this work is twofold: first, to compare the convergence properties of the network outputs under various…

Machine Learning · Computer Science 2026-01-27 Nikos Georgoudios , Konstantinos Spiliopoulos , Justin Sirignano

We propose WSAC (Weighted Safe Actor-Critic), a novel algorithm for Safe Offline Reinforcement Learning (RL) under functional approximation, which can robustly optimize policies to improve upon an arbitrary reference policy with limited…

Machine Learning · Computer Science 2024-11-01 Honghao Wei , Xiyue Peng , Arnob Ghosh , Xin Liu

Policy gradient methods in actor-critic reinforcement learning (RL) have become perhaps the most promising approaches to solving continuous optimal control problems. However, the trial-and-error nature of RL and the inherent randomness…

Machine Learning · Computer Science 2024-04-19 Ruofan Wu , Junmin Zhong , Jennie Si

Safety is essential for reinforcement learning (RL) applied in real-world situations. Chance constraints are suitable to represent the safety requirements in stochastic systems. Previous chance-constrained RL methods usually have a low…

Machine Learning · Computer Science 2021-03-17 Baiyu Peng , Yao Mu , Yang Guan , Shengbo Eben Li , Yuming Yin , Jianyu Chen

Existing actor-critic algorithms, which are popular for continuous control reinforcement learning (RL) tasks, suffer from poor sample efficiency due to lack of principled exploration mechanism within them. Motivated by the success of…

Machine Learning · Computer Science 2025-01-30 Haque Ishfaq , Guangyuan Wang , Sami Nur Islam , Doina Precup

Deep reinforcement learning (RL) algorithms can use high-capacity deep networks to learn directly from image observations. However, these high-dimensional observation spaces present a number of challenges in practice, since the policy must…

Machine Learning · Computer Science 2020-10-27 Alex X. Lee , Anusha Nagabandi , Pieter Abbeel , Sergey Levine

This work presents a comprehensive analysis to regularize the Soft Actor-Critic (SAC) algorithm with automatic temperature adjustment. The the policy evaluation, the policy improvement and the temperature adjustment are reformulated,…

Machine Learning · Computer Science 2023-05-24 Ben You

Actor-critic methods, a type of model-free Reinforcement Learning, have been successfully applied to challenging tasks in continuous control, often achieving state-of-the art performance. However, wide-scale adoption of these methods in…

Machine Learning · Statistics 2019-10-29 Kamil Ciosek , Quan Vuong , Robert Loftin , Katja Hofmann