Neural algorithmic reasoning studies the problem of learning algorithms with neural networks, especially with graph architectures. A recent proposal, XLVIN, reaps the benefits of using a graph neural network that simulates the value iteration algorithm in deep reinforcement learning agents. It allows model-free planning without access to privileged information about the environment, which is usually unavailable. However, XLVIN only supports discrete action spaces, and is hence nontrivially applicable to most tasks of real-world interest. We expand XLVIN to continuous action spaces by discretization, and evaluate several selective expansion policies to deal with the large planning graphs. Our proposal, CNAP, demonstrates how neural algorithmic reasoning can make a measurable impact in higher-dimensional continuous control settings, such as MuJoCo, bringing gains in low-data settings and outperforming model-free baselines.
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近年来近年来,加固学习方法已经发展了一系列政策梯度方法,主要用于建模随机政策的高斯分布。然而,高斯分布具有无限的支持,而现实世界应用通常具有有限的动作空间。如果它提供有限支持,则该解剖会导致可以消除的估计偏差,因为它提出了有限的支持。在这项工作中,我们调查如何在Openai健身房的两个连续控制任务中训练该测试策略在训练时执行该测试策略。对于这两个任务来说,测试政策在代理人的最终预期奖励方面优于高斯政策,也显示出更多的稳定性和更快的培训过程融合。对于具有高维图像输入的卡路里环境,在高斯政策中,代理的成功率提高了63%。
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最近的研究表明,图形神经网络(GNNS)可以学习适用于典型的多层Perceptron(MLP)的运动控制的政策,具有卓越的转移和多任务性能(Wang等,2018; Huang Et al。,2020)。到目前为止,由于传感器和致动器的数量增长,GNN的性能随着传感器和执行器的数量而迅速变化,结果已经限于对小剂量的训练。在监督学习环境中使用GNN的关键动机是它们对大图的适用性,但尚未实现这种益处用于运动控制。我们将宽松的GNN架构中的弱点识别出导致这种较差的缩放:在网络中的MLP中过度拟合,用于编码,解码和传播消息。为了打击这一点,我们引入了雪花,一种用于高维连续控制的GNN训练方法,可以冻结受影响的网络部分中的参数。雪花显着提高了GNN在大型代理上的运动控制的性能,现在与MLP的性能相匹配,以及具有卓越的转移性能。
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组合优化是运营研究和计算机科学领域的一个公认领域。直到最近,它的方法一直集中在孤立地解决问题实例,而忽略了它们通常源于实践中的相关数据分布。但是,近年来,人们对使用机器学习,尤其是图形神经网络(GNN)的兴趣激增,作为组合任务的关键构件,直接作为求解器或通过增强确切的求解器。GNN的电感偏差有效地编码了组合和关系输入,因为它们对排列和对输入稀疏性的意识的不变性。本文介绍了对这个新兴领域的最新主要进步的概念回顾,旨在优化和机器学习研究人员。
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机器人的形态和行为的互相适应变得与快速的3D-制造方法和高效的深强化学习算法的出现越来越重要。对于互相适应的方法应用到真实世界的一个主要挑战是由于模型和仿真不准确的模拟到现实的差距。然而,以前的工作主要集中在形态开发的分析模型,并用大量的用户群(微)模拟器的进化适应的研究,忽视的模拟到现实差距的存在和在现实世界中制造周期的成本。本文提出了一种新的办法,结合经典的高频率计算昂贵的图形神经网络的代理数据高效互相适应深层神经网络具有不同度的自由度数。在仿真结果表明,新方法可以通过有效的设计优化与离线强化学习相结合共同适应的生产周期这样一个有限的数量中的代理程序,它允许在今后的工作中直接应用到真实世界的互相适应任务评估
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Deep reinforcement learning is poised to revolutionise the field of AI and represents a step towards building autonomous systems with a higher level understanding of the visual world. Currently, deep learning is enabling reinforcement learning to scale to problems that were previously intractable, such as learning to play video games directly from pixels. Deep reinforcement learning algorithms are also applied to robotics, allowing control policies for robots to be learned directly from camera inputs in the real world. In this survey, we begin with an introduction to the general field of reinforcement learning, then progress to the main streams of value-based and policybased methods. Our survey will cover central algorithms in deep reinforcement learning, including the deep Q-network, trust region policy optimisation, and asynchronous advantage actor-critic. In parallel, we highlight the unique advantages of deep neural networks, focusing on visual understanding via reinforcement learning. To conclude, we describe several current areas of research within the field.
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尽管深度强化学习(RL)最近取得了许多成功,但其方法仍然效率低下,这使得在数据方面解决了昂贵的许多问题。我们的目标是通过利用未标记的数据中的丰富监督信号来进行学习状态表示,以解决这一问题。本文介绍了三种不同的表示算法,可以访问传统RL算法使用的数据源的不同子集使用:(i)GRICA受到独立组件分析(ICA)的启发,并训练深层神经网络以输出统计独立的独立特征。输入。 Grica通过最大程度地减少每个功能与其他功能之间的相互信息来做到这一点。此外,格里卡仅需要未分类的环境状态。 (ii)潜在表示预测(LARP)还需要更多的上下文:除了要求状态作为输入外,它还需要先前的状态和连接它们的动作。该方法通过预测当前状态和行动的环境的下一个状态来学习状态表示。预测器与图形搜索算法一起使用。 (iii)重新培训通过训练深层神经网络来学习国家表示,以学习奖励功能的平滑版本。该表示形式用于预处理输入到深度RL,而奖励预测指标用于奖励成型。此方法仅需要环境中的状态奖励对学习表示表示。我们发现,每种方法都有其优势和缺点,并从我们的实验中得出结论,包括无监督的代表性学习在RL解决问题的管道中可以加快学习的速度。
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深度强化学习(DRL)赋予了各种人工智能领域,包括模式识别,机器人技术,推荐系统和游戏。同样,图神经网络(GNN)也证明了它们在图形结构数据的监督学习方面的出色表现。最近,GNN与DRL用于图形结构环境的融合引起了很多关注。本文对这些混合动力作品进行了全面评论。这些作品可以分为两类:(1)算法增强,其中DRL和GNN相互补充以获得更好的实用性; (2)特定于应用程序的增强,其中DRL和GNN相互支持。这种融合有效地解决了工程和生命科学方面的各种复杂问题。基于审查,我们进一步分析了融合这两个领域的适用性和好处,尤其是在提高通用性和降低计算复杂性方面。最后,集成DRL和GNN的关键挑战以及潜在的未来研究方向被突出显示,这将引起更广泛的机器学习社区的关注。
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The policy gradient method enjoys the simplicity of the objective where the agent optimizes the cumulative reward directly. Moreover, in the continuous action domain, parameterized distribution of action distribution allows easy control of exploration, resulting from the variance of the representing distribution. Entropy can play an essential role in policy optimization by selecting the stochastic policy, which eventually helps better explore the environment in reinforcement learning (RL). However, the stochasticity often reduces as the training progresses; thus, the policy becomes less exploratory. Additionally, certain parametric distributions might only work for some environments and require extensive hyperparameter tuning. This paper aims to mitigate these issues. In particular, we propose an algorithm called Robust Policy Optimization (RPO), which leverages a perturbed distribution. We hypothesize that our method encourages high-entropy actions and provides a way to represent the action space better. We further provide empirical evidence to verify our hypothesis. We evaluated our methods on various continuous control tasks from DeepMind Control, OpenAI Gym, Pybullet, and IsaacGym. We observed that in many settings, RPO increases the policy entropy early in training and then maintains a certain level of entropy throughout the training period. Eventually, our agent RPO shows consistently improved performance compared to PPO and other techniques: entropy regularization, different distributions, and data augmentation. Furthermore, in several settings, our method stays robust in performance, while other baseline mechanisms fail to improve and even worsen the performance.
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强化学习和最近的深度增强学习是解决如Markov决策过程建模的顺序决策问题的流行方法。问题和选择算法和超参数的RL建模需要仔细考虑,因为不同的配置可能需要完全不同的性能。这些考虑因素主要是RL专家的任务;然而,RL在研究人员和系统设计师不是RL专家的其他领域中逐渐变得流行。此外,许多建模决策,例如定义状态和动作空间,批次的大小和批量更新的频率以及时间戳的数量通常是手动进行的。由于这些原因,RL框架的自动化不同组成部分具有重要意义,近年来它引起了很多关注。自动RL提供了一个框架,其中RL的不同组件包括MDP建模,算法选择和超参数优化是自动建模和定义的。在本文中,我们探讨了可以在自动化RL中使用的文献和目前的工作。此外,我们讨论了Autorl中的挑战,打开问题和研究方向。
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我们介绍了一种改进政策改进的方法,该方法在基于价值的强化学习(RL)的贪婪方法与基于模型的RL的典型计划方法之间进行了插值。新方法建立在几何视野模型(GHM,也称为伽马模型)的概念上,该模型对给定策略的折现状态验证分布进行了建模。我们表明,我们可以通过仔细的基本策略GHM的仔细组成,而无需任何其他学习,可以评估任何非马尔科夫策略,以固定的概率在一组基本马尔可夫策略之间切换。然后,我们可以将广义政策改进(GPI)应用于此类非马尔科夫政策的收集,以获得新的马尔可夫政策,通常将其表现优于其先驱。我们对这种方法提供了彻底的理论分析,开发了转移和标准RL的应用,并在经验上证明了其对标准GPI的有效性,对充满挑战的深度RL连续控制任务。我们还提供了GHM培训方法的分析,证明了关于先前提出的方法的新型收敛结果,并显示了如何在深度RL设置中稳定训练这些模型。
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VAR-VAR控制(VVC)是通过控制电源系统中的执行器在健康状态内运行电源分配系统的问题。现有作品主要采用代表电力系统(带有树拓扑的图)作为训练深钢筋学习(RL)策略的向量的常规例程。我们提出了一个将RL与图形神经网络相结合的框架,并研究VVC设置中基于图的策略的好处和局限性。我们的结果表明,与向量表示相比,基于图的策略会渐近地收敛到相同的奖励。我们对观察和行动的影响进行进一步分析:在观察端,我们研究了基于图形的策略对功率系统中两个典型数据采集错误的鲁棒性,即传感器通信失败和测量错误。在动作端,我们表明执行器对系统有各种影响,因此使用由电源系统拓扑引起的图表表示可能不是最佳选择。最后,我们进行了一项案例研究,以证明读取功能架构和图形增强的选择可以进一步提高训练性能和鲁棒性。
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Adequately assigning credit to actions for future outcomes based on their contributions is a long-standing open challenge in Reinforcement Learning. The assumptions of the most commonly used credit assignment method are disadvantageous in tasks where the effects of decisions are not immediately evident. Furthermore, this method can only evaluate actions that have been selected by the agent, making it highly inefficient. Still, no alternative methods have been widely adopted in the field. Hindsight Credit Assignment is a promising, but still unexplored candidate, which aims to solve the problems of both long-term and counterfactual credit assignment. In this thesis, we empirically investigate Hindsight Credit Assignment to identify its main benefits, and key points to improve. Then, we apply it to factored state representations, and in particular to state representations based on the causal structure of the environment. In this setting, we propose a variant of Hindsight Credit Assignment that effectively exploits a given causal structure. We show that our modification greatly decreases the workload of Hindsight Credit Assignment, making it more efficient and enabling it to outperform the baseline credit assignment method on various tasks. This opens the way to other methods based on given or learned causal structures.
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A long-standing challenge in artificial intelligence is lifelong learning. In lifelong learning, many tasks are presented in sequence and learners must efficiently transfer knowledge between tasks while avoiding catastrophic forgetting over long lifetimes. On these problems, policy reuse and other multi-policy reinforcement learning techniques can learn many tasks. However, they can generate many temporary or permanent policies, resulting in memory issues. Consequently, there is a need for lifetime-scalable methods that continually refine a policy library of a pre-defined size. This paper presents a first approach to lifetime-scalable policy reuse. To pre-select the number of policies, a notion of task capacity, the maximal number of tasks that a policy can accurately solve, is proposed. To evaluate lifetime policy reuse using this method, two state-of-the-art single-actor base-learners are compared: 1) a value-based reinforcement learner, Deep Q-Network (DQN) or Deep Recurrent Q-Network (DRQN); and 2) an actor-critic reinforcement learner, Proximal Policy Optimisation (PPO) with or without Long Short-Term Memory layer. By selecting the number of policies based on task capacity, D(R)QN achieves near-optimal performance with 6 policies in a 27-task MDP domain and 9 policies in an 18-task POMDP domain; with fewer policies, catastrophic forgetting and negative transfer are observed. Due to slow, monotonic improvement, PPO requires fewer policies, 1 policy for the 27-task domain and 4 policies for the 18-task domain, but it learns the tasks with lower accuracy than D(R)QN. These findings validate lifetime-scalable policy reuse and suggest using D(R)QN for larger and PPO for smaller library sizes.
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这篇简短的评论旨在使读者熟悉与计划,调度和学习有关的最新作品。首先,我们研究最先进的计划算法。我们简要介绍神经网络。然后,我们更详细地探索图形神经网络,这是一种适合处理图形结构输入的神经网络的最新变体。我们简要描述了强化学习算法和迄今为止设计的一些方法的概念。接下来,我们研究了一些成功的方法,结合了用于路径规划的神经网络。最后,我们专注于不确定性的时间计划问题。
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连续控制的强化学习(RL)通常采用其支持涵盖整个动作空间的分布。在这项工作中,我们调查了培训的代理经常更喜欢在该空间的界限中普遍采取行动的俗称已知的现象。我们在最佳控制中汲取理论联系,以发出Bang-Bang行为的出现,并在各种最近的RL算法中提供广泛的实证评估。我们通过伯努利分布替换正常高斯,该分布仅考虑沿着每个动作维度的极端 - Bang-Bang控制器。令人惊讶的是,这在几种连续控制基准测试中实现了最先进的性能 - 与机器人硬件相比,能量和维护成本影响控制器选择。由于勘探,学习和最终解决方案纠缠在RL中,我们提供了额外的模仿学习实验,以减少探索对我们分析的影响。最后,我们表明我们的观察结果概括了旨在模拟现实世界挑战和评估因素来减轻Bang-Bang解决方案的因素的环境。我们的调查结果强调了对基准测试连续控制算法的挑战,特别是在潜在的现实世界应用中。
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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.
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资产分配(或投资组合管理)是确定如何最佳将有限预算的资金分配给一系列金融工具/资产(例如股票)的任务。这项研究调查了使用无模型的深RL代理应用于投资组合管理的增强学习(RL)的性能。我们培训了几个RL代理商的现实股票价格,以学习如何执行资产分配。我们比较了这些RL剂与某些基线剂的性能。我们还比较了RL代理,以了解哪些类别的代理表现更好。从我们的分析中,RL代理可以执行投资组合管理的任务,因为它们的表现明显优于基线代理(随机分配和均匀分配)。四个RL代理(A2C,SAC,PPO和TRPO)总体上优于最佳基线MPT。这显示了RL代理商发现更有利可图的交易策略的能力。此外,基于价值和基于策略的RL代理之间没有显着的性能差异。演员批评者的表现比其他类型的药物更好。同样,在政策代理商方面的表现要好,因为它们在政策评估方面更好,样品效率在投资组合管理中并不是一个重大问题。这项研究表明,RL代理可以大大改善资产分配,因为它们的表现优于强基础。基于我们的分析,在政策上,参与者批评的RL药物显示出最大的希望。
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We consider the problem of multi-agent navigation and collision avoidance when observations are limited to the local neighborhood of each agent. We propose InforMARL, a novel architecture for multi-agent reinforcement learning (MARL) which uses local information intelligently to compute paths for all the agents in a decentralized manner. Specifically, InforMARL aggregates information about the local neighborhood of agents for both the actor and the critic using a graph neural network and can be used in conjunction with any standard MARL algorithm. We show that (1) in training, InforMARL has better sample efficiency and performance than baseline approaches, despite using less information, and (2) in testing, it scales well to environments with arbitrary numbers of agents and obstacles.
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深度加强学习(RL)最近在机器人连续控制任务中表现出很大的承诺。尽管如此,在该静脉中心围绕集中式学习设置的研究,这在很大程度上依赖于机器人的所有组件之间的通信可用性。然而,现实世界中的代理商经常以分散的方式运作,由于潜伏期要求,有限的电力预算和安全问题。通过将机器人组件作为分​​散剂的系统配制,这项工作提出了一种用于连续控制的分散的多效增强学习框架。为此,我们首先开发一个合作的多眼PPO框架,允许在执行期间训练和分散的操作期间集中优化。但是,该系统仅接收全局奖励信号,该信号不会归因于每个代理。为了解决这一挑战,我们进一步提出了一个通用的游戏理论信用分配框架,它计算特定于代理的奖励信号。最后但并非最不重要的是,我们还将基于模型的RL模块纳入了我们的信用分配框架,这导致采样效率的显着提高。我们展示了我们对Mujoco机器人控制任务的实验结果框架的有效性。对于演示视频,请访问:https://youtu.be/gfyvpm4svey。
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