抽象已被广泛研究，以提高增强学习算法的效率和概括。在本文中，我们研究了连续控制环境中的抽象。我们将MDP同态的定义扩展到连续状态空间中的连续作用。我们在抽象MDP上得出了策略梯度定理，这使我们能够利用环境的近似对称性进行策略优化。基于该定理，我们提出了一种能够使用Lax Bisimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation Mimulation。我们证明了我们方法对DeepMind Control Suite中基准任务的有效性。我们的方法利用MDP同态来表示学习的能力会导致从像素观测中学习时的性能。

我们在马尔可夫决策过程的状态空间上提出了一种新的行为距离，并展示使用该距离作为塑造深度加强学习代理的学习言论的有效手段。虽然由于高计算成本和基于样本的算法缺乏缺乏样本的距离，但是，虽然现有的国家相似性通常难以在规模上学习，但我们的新距离解决了这两个问题。除了提供详细的理论分析外，我们还提供了学习该距离的经验证据，与价值函数产生的结构化和信息化表示，包括对街机学习环境基准的强劲结果。

政策梯度定理（Sutton等，2000）规定了目标政策下的累积折扣国家分配以近似梯度。实际上，基于该定理的大多数算法都打破了这一假设，引入了分布转移，该分配转移可能导致逆转溶液的收敛性。在本文中，我们提出了一种新的方法，可以从开始状态重建政策梯度，而无需采取特定的采样策略。可以根据梯度评论家来简化此形式的策略梯度计算，由于梯度的新钟声方程式，可以递归估算。通过使用来自差异数据流的梯度评论家的时间差异更新，我们开发了第一个以无模型方式避开分布变化问题的估计器。我们证明，在某些可实现的条件下，无论采样策略如何，我们的估计器都是公正的。我们从经验上表明，我们的技术在存在非政策样品的情况下实现了卓越的偏见变化权衡和性能。

In value-based reinforcement learning methods such as deep Q-learning, function approximation errors are known to lead to overestimated value estimates and suboptimal policies. We show that this problem persists in an actor-critic setting and propose novel mechanisms to minimize its effects on both the actor and the critic. Our algorithm builds on Double Q-learning, by taking the minimum value between a pair of critics to limit overestimation. We draw the connection between target networks and overestimation bias, and suggest delaying policy updates to reduce per-update error and further improve performance. We evaluate our method on the suite of OpenAI gym tasks, outperforming the state of the art in every environment tested.

Model-free deep reinforcement learning (RL) algorithms have been demonstrated on a range of challenging decision making and control tasks. However, these methods typically suffer from two major challenges: very high sample complexity and brittle convergence properties, which necessitate meticulous hyperparameter tuning. Both of these challenges severely limit the applicability of such methods to complex, real-world domains. In this paper, we propose soft actor-critic, an offpolicy actor-critic deep RL algorithm based on the maximum entropy reinforcement learning framework. In this framework, the actor aims to maximize expected reward while also maximizing entropy. That is, to succeed at the task while acting as randomly as possible. Prior deep RL methods based on this framework have been formulated as Q-learning methods. By combining off-policy updates with a stable stochastic actor-critic formulation, our method achieves state-of-the-art performance on a range of continuous control benchmark tasks, outperforming prior on-policy and off-policy methods. Furthermore, we demonstrate that, in contrast to other off-policy algorithms, our approach is very stable, achieving very similar performance across different random seeds.

In this paper, hypernetworks are trained to generate behaviors across a range of unseen task conditions, via a novel TD-based training objective and data from a set of near-optimal RL solutions for training tasks. This work relates to meta RL, contextual RL, and transfer learning, with a particular focus on zero-shot performance at test time, enabled by knowledge of the task parameters (also known as context). Our technical approach is based upon viewing each RL algorithm as a mapping from the MDP specifics to the near-optimal value function and policy and seek to approximate it with a hypernetwork that can generate near-optimal value functions and policies, given the parameters of the MDP. We show that, under certain conditions, this mapping can be considered as a supervised learning problem. We empirically evaluate the effectiveness of our method for zero-shot transfer to new reward and transition dynamics on a series of continuous control tasks from DeepMind Control Suite. Our method demonstrates significant improvements over baselines from multitask and meta RL approaches.

一种被称为优先体验重播（PER）的广泛研究的深钢筋学习（RL）技术使代理可以从与其时间差异（TD）误差成正比的过渡中学习。尽管已经表明，PER是离散作用域中深度RL方法总体性能的最关键组成部分之一，但许多经验研究表明，在连续控制中，它的表现非常低于参与者 - 批评算法。从理论上讲，我们表明，无法有效地通过具有较大TD错误的过渡对演员网络进行训练。结果，在Q网络下计算的近似策略梯度与在最佳Q功能下计算的实际梯度不同。在此激励的基础上，我们引入了一种新颖的经验重播抽样框架，用于演员批评方法，该框架还认为稳定性和最新发现的问题是Per的经验表现不佳。引入的算法提出了对演员和评论家网络的有效和高效培训的改进的新分支。一系列广泛的实验验证了我们的理论主张，并证明了引入的方法显着优于竞争方法，并获得了与标准的非政策参与者 - 批评算法相比，获得最先进的结果。

强化学习的主要方法是根据预期的回报将信贷分配给行动。但是，我们表明回报可能取决于政策，这可能会导致价值估计的过度差异和减慢学习的速度。取而代之的是，我们证明了优势函数可以解释为因果效应，并与因果关系共享相似的属性。基于此洞察力，我们提出了直接优势估计（DAE），这是一种可以对优势函数进行建模并直接从政策数据进行估算的新方法，同时同时最大程度地减少了返回的方差而无需（操作 - ）值函数。我们还通过显示如何无缝整合到DAE中来将我们的方法与时间差异方法联系起来。所提出的方法易于实施，并且可以通过现代参与者批评的方法很容易适应。我们对三个离散控制域进行经验评估DAE，并表明它可以超过广义优势估计（GAE），这是优势估计的强大基线，当将大多数环境应用于策略优化时。

Effectively leveraging large, previously collected datasets in reinforcement learning (RL) is a key challenge for large-scale real-world applications. Offline RL algorithms promise to learn effective policies from previously-collected, static datasets without further interaction. However, in practice, offline RL presents a major challenge, and standard off-policy RL methods can fail due to overestimation of values induced by the distributional shift between the dataset and the learned policy, especially when training on complex and multi-modal data distributions. In this paper, we propose conservative Q-learning (CQL), which aims to address these limitations by learning a conservative Q-function such that the expected value of a policy under this Q-function lower-bounds its true value. We theoretically show that CQL produces a lower bound on the value of the current policy and that it can be incorporated into a policy learning procedure with theoretical improvement guarantees. In practice, CQL augments the standard Bellman error objective with a simple Q-value regularizer which is straightforward to implement on top of existing deep Q-learning and actor-critic implementations. On both discrete and continuous control domains, we show that CQL substantially outperforms existing offline RL methods, often learning policies that attain 2-5 times higher final return, especially when learning from complex and multi-modal data distributions.Preprint. Under review.

由于策略梯度定理导致的策略设置存在各种理论上 - 声音策略梯度算法，其为梯度提供了简化的形式。然而，由于存在多重目标和缺乏明确的脱助政策政策梯度定理，截止策略设置不太明确。在这项工作中，我们将这些目标统一到一个违规目标，并为此统一目标提供了政策梯度定理。推导涉及强调的权重和利息职能。我们显示多种策略来近似梯度，以识别权重（ACE）称为Actor评论家的算法。我们证明了以前（半梯度）脱离政策演员 - 评论家 - 特别是offpac和DPG - 收敛到错误的解决方案，而Ace找到最佳解决方案。我们还强调为什么这些半梯度方法仍然可以在实践中表现良好，表明ace中的方差策略。我们经验研究了两个经典控制环境的若干ACE变体和基于图像的环境，旨在说明每个梯度近似的权衡。我们发现，通过直接逼近强调权重，ACE在所有测试的所有设置中执行或优于offpac。

基于模型的强化学习（RL）的主要挑战之一是决定应建模环境的哪些方面。值等价（VE）原则提出了一个简单的答案，对此问题：模型应该捕获与基于价值的规划相关的环境的方面。从技术上讲，VE基于一组策略和一组功能区分模型：如果贝尔曼运营商诱导策略，则据说模型是对环境的VE，在应用于功能时产生正确的结果。随着策略数量的增加，VE模型集缩小，最终折叠到对应于完美模型的单点。因此，VE原理的基本问题是如何选择足以规划的最小策略和功能。在本文中，我们对回答这个问题进行了重要一步。我们首先通过朝鲜钟人机运营商的$ k $申请概括为达到秩序的概念。这导致了一个VE类的家庭，尺寸随着$ k \ lightarow \ idty $而增加。在极限中，所有功能都成为价值函数，我们有一个特殊的实例化，我们称之为适当的VE或简单的PVE。与VE不同，PVE类可能包含多种型号，即使在使用所有值函数时也可以包含多个模型。至关重要的是，所有这些模型都足以规划，这意味着他们将产生最佳政策尽管他们可能忽略了环境的许多方面。我们构建用于学习PVE模型的损失函数，并认为诸如Muzero的流行算法可以被理解为最小化这种损失的上限。我们利用这一联系提出了对Muzero的修改，并表明它可以在实践中提高性能。

在许多增强学习（RL）应用中，观察空间由人类开发人员指定并受到物理实现的限制，因此可能会随时间的巨大变化（例如，观察特征的数量增加）。然而，当观察空间发生变化时，前一项策略可能由于输入特征不匹配而失败，并且另一个策略必须从头开始培训，这在计算和采样复杂性方面效率低。在理论上见解之后，我们提出了一种新颖的算法，该算法提取源任务中的潜在空间动态，并将动态模型传送到目标任务用作基于模型的常规程序。我们的算法适用于观察空间的彻底变化（例如，从向量的基于矢量的观察到图像的观察），没有任何任务映射或目标任务的任何先前知识。实证结果表明，我们的算法显着提高了目标任务中学习的效率和稳定性。

这项工作探讨了如何从具有深度加强学习方法的基于图像的观测中学习鲁棒和最广泛的状态表示。解决了在现有的Bisimulation度量工作中的计算复杂性，严格假设和表示崩溃挑战，我们设计了简单的状态表示（SIMSR）运算符，该操作员实现了等效功能，同时通过与Bisimulation度量进行比较来降低顺序的复杂性。SIMSR使我们能够设计一种基于随机逼近的方法，该方法几乎可以从观察到潜在表示空间的观察中学习映射函数（编码器）。除了理论分析外，我们在Visual Mujoco任务中尝试并与最近的最先进解决方案进行了实验。结果表明，我们的模型通常达到更好的性能，具有更好的鲁棒性和良好的概率。

与政策策略梯度技术相比，使用先前收集的数据的无模型的无模型深钢筋学习（RL）方法可以提高采样效率。但是，当利益政策的分布与收集数据的政策之间的差异时，非政策学习变得具有挑战性。尽管提出了良好的重要性抽样和范围的政策梯度技术来补偿这种差异，但它们通常需要一系列长轨迹，以增加计算复杂性并引起其他问题，例如消失或爆炸梯度。此外，由于需要行动概率，它们对连续动作领域的概括严格受到限制，这不适合确定性政策。为了克服这些局限性，我们引入了一种替代的非上政策校正算法，用于连续作用空间，参与者 - 批判性非政策校正（AC-OFF-POC），以减轻先前收集的数据引入的潜在缺陷。通过由代理商对随机采样批次过渡的状态的最新动作决策计算出的新颖差异度量，该方法不需要任何策略的实际或估计的行动概率，并提供足够的一步重要性抽样。理论结果表明，引入的方法可以使用固定的独特点获得收缩映射，从而可以进行“安全”的非政策学习。我们的经验结果表明，AC-Off-POC始终通过有效地安排学习率和Q学习和政策优化的学习率，以比竞争方法更少的步骤改善最新的回报。

表示学习通常通过管理维度的诅咒在加强学习中起关键作用。代表性的算法类别利用了随机过渡动力学的光谱分解，以构建在理想化环境中具有强大理论特性的表示。但是，当前的光谱方法的适用性有限，因为它们是用于仅国家的聚合并源自策略依赖性过渡内核的，而无需考虑勘探问题。为了解决这些问题，我们提出了一种替代光谱方法，光谱分解表示（SPEDER），该方法从动力学中提取了国家行动抽象而不诱导虚假依赖数据收集策略，同时还可以平衡探索访问权分析交易 - 在学习过程中关闭。理论分析确定了在线和离线设置中所提出的算法的样本效率。此外，一项实验研究表明，在几个基准测试中，比当前的最新算法表现出色。

尽管政策梯度方法的普及日益越来越大，但它们尚未广泛用于样品稀缺应用，例如机器人。通过充分利用可用信息，可以提高样本效率。作为强化学习中的关键部件，奖励功能通常仔细设计以引导代理商。因此，奖励功能通常是已知的，允许访问不仅可以访问标量奖励信号，而且允许奖励梯度。为了从奖励梯度中受益，之前的作品需要了解环境动态，这很难获得。在这项工作中，我们开发\ Textit {奖励政策梯度}估计器，这是一种新的方法，可以在不学习模型的情况下整合奖励梯度。绕过模型动态允许我们的估算器实现更好的偏差差异，这导致更高的样本效率，如经验分析所示。我们的方法还提高了在不同的Mujoco控制任务上的近端策略优化的性能。

Advances in reinforcement learning have led to its successful application in complex tasks with continuous state and action spaces. Despite these advances in practice, most theoretical work pertains to finite state and action spaces. We propose building a theoretical understanding of continuous state and action spaces by employing a geometric lens. Central to our work is the idea that the transition dynamics induce a low dimensional manifold of reachable states embedded in the high-dimensional nominal state space. We prove that, under certain conditions, the dimensionality of this manifold is at most the dimensionality of the action space plus one. This is the first result of its kind, linking the geometry of the state space to the dimensionality of the action space. We empirically corroborate this upper bound for four MuJoCo environments. We further demonstrate the applicability of our result by learning a policy in this low dimensional representation. To do so we introduce an algorithm that learns a mapping to a low dimensional representation, as a narrow hidden layer of a deep neural network, in tandem with the policy using DDPG. Our experiments show that a policy learnt this way perform on par or better for four MuJoCo control suite tasks.

In this paper we consider deterministic policy gradient algorithms for reinforcement learning with continuous actions. The deterministic policy gradient has a particularly appealing form: it is the expected gradient of the action-value function. This simple form means that the deterministic policy gradient can be estimated much more efficiently than the usual stochastic policy gradient. To ensure adequate exploration, we introduce an off-policy actor-critic algorithm that learns a deterministic target policy from an exploratory behaviour policy. We demonstrate that deterministic policy gradient algorithms can significantly outperform their stochastic counterparts in high-dimensional action spaces.

Reinforcement learning (RL) gained considerable attention by creating decision-making agents that maximize rewards received from fully observable environments. However, many real-world problems are partially or noisily observable by nature, where agents do not receive the true and complete state of the environment. Such problems are formulated as partially observable Markov decision processes (POMDPs). Some studies applied RL to POMDPs by recalling previous decisions and observations or inferring the true state of the environment from received observations. Nevertheless, aggregating observations and decisions over time is impractical for environments with high-dimensional continuous state and action spaces. Moreover, so-called inference-based RL approaches require large number of samples to perform well since agents eschew uncertainty in the inferred state for the decision-making. Active inference is a framework that is naturally formulated in POMDPs and directs agents to select decisions by minimising expected free energy (EFE). This supplies reward-maximising (exploitative) behaviour in RL, with an information-seeking (exploratory) behaviour. Despite this exploratory behaviour of active inference, its usage is limited to discrete state and action spaces due to the computational difficulty of the EFE. We propose a unified principle for joint information-seeking and reward maximization that clarifies a theoretical connection between active inference and RL, unifies active inference and RL, and overcomes their aforementioned limitations. Our findings are supported by strong theoretical analysis. The proposed framework's superior exploration property is also validated by experimental results on partial observable tasks with high-dimensional continuous state and action spaces. Moreover, the results show that our model solves reward-free problems, making task reward design optional.

Model-based reinforcement learning (RL) methods are appealing in the offline setting because they allow an agent to reason about the consequences of actions without interacting with the environment. Prior methods learn a 1-step dynamics model, which predicts the next state given the current state and action. These models do not immediately tell the agent which actions to take, but must be integrated into a larger RL framework. Can we model the environment dynamics in a different way, such that the learned model does directly indicate the value of each action? In this paper, we propose Contrastive Value Learning (CVL), which learns an implicit, multi-step model of the environment dynamics. This model can be learned without access to reward functions, but nonetheless can be used to directly estimate the value of each action, without requiring any TD learning. Because this model represents the multi-step transitions implicitly, it avoids having to predict high-dimensional observations and thus scales to high-dimensional tasks. Our experiments demonstrate that CVL outperforms prior offline RL methods on complex continuous control benchmarks.