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Chris Lu

18 accepted papers

2025

Kinetix: Investigating the Training of General Agents through Open-Ended Physics-Based Control Tasks

ICLR 2025oral

While large models trained with self-supervised learning on offline datasets have shown remarkable capabilities in text and image domains, achieving the same generalisation for agents that act in sequential decision problems remains an open challenge. In this work, we take a step towards this goal b…

2025

Learning mirror maps in policy mirror descent

ICLR 2025poster

Policy Mirror Descent (PMD) is a popular framework in reinforcement learning, serving as a unifying perspective that encompasses numerous algorithms. These algorithms are derived through the selection of a mirror map and enjoy finite-time convergence guarantees. Despite its popularity, the explorati…

Cited by 0SourcePDFScholar
2025

NAVIX: Scaling MiniGrid Environments with JAX

NeurIPS 2025poster

As Deep Reinforcement Learning (Deep RL) research moves towards solving large-scale worlds, efficient environment simulations become crucial for rapid experimentation. However, most existing environments struggle to scale to high throughput, setting back meaningful progress. Interactions are typical…

Cited by 0SourcecodeScholar
2024

Artificial Generational Intelligence: Cultural Accumulation in Reinforcement Learning

NeurIPS 2024poster

Cultural accumulation drives the open-ended and diverse progress in capabilities spanning human history. It builds an expanding body of knowledge and skills by combining individual exploration with inter-generational information transmission. Despite its widespread success among humans, the capacity…

2024

Behaviour Distillation

ICLR 2024poster

Dataset distillation aims to condense large datasets into a small number of synthetic examples that can be used as drop-in replacements when training new models. It has applications to interpretability, neural architecture search, privacy, and continual learning. Despite strong successes in supervis…

2024

Can Learned Optimization Make Reinforcement Learning Less Difficult?

NeurIPS 2024spotlight

While reinforcement learning (RL) holds great potential for decision making in the real world, it suffers from a number of unique difficulties which often need specific consideration. In particular: it is highly non-stationary; suffers from high degrees of plasticity loss; and requires exploration t…

2024

Discovering Preference Optimization Algorithms with and for Large Language Models

NeurIPS 2024poster

Offline preference optimization is a key method for enhancing and controlling the quality of Large Language Model (LLM) outputs. Typically, preference optimization is approached as an offline supervised learning task using manually crafted convex loss functions. While these methods are based on theo…

Cited by 16SourcePDFScholar
2024

Discovering Temporally-Aware Reinforcement Learning Algorithms

ICLR 2024poster

Recent advancements in meta-learning have enabled the automatic discovery of novel reinforcement learning algorithms parameterized by surrogate objective functions. To improve upon manually designed algorithms, the parameterization of this learned objective function must be expressive enough to repr…

2024

EvIL: Evolution Strategies for Generalisable Imitation Learning

ICML 2024poster

Often times in imitation learning (IL), the environment we collect expert demonstrations in and the environment we want to deploy our learned policy in aren't exactly the same (e.g. demonstrations collected in simulation but deployment in the real world). Compared to policy-centric approaches to IL…

2024

JaxMARL: Multi-Agent RL Environments and Algorithms in JAX

NeurIPS 2024poster

Benchmarks are crucial in the development of machine learning algorithms, significantly influencing reinforcement learning (RL) research through the available environments. Traditionally, RL environments run on the CPU, which limits their scalability with the computational resources typically availa…

2024

ReLU to the Rescue: Improve Your On-Policy Actor-Critic with Positive Advantages

ICML 2024poster

This paper proposes a step toward approximate Bayesian inference in on-policy actor-critic deep reinforcement learning. It is implemented through three changes to the Asynchronous Advantage Actor-Critic (A3C) algorithm: (1) applying a ReLU function to advantage estimates, (2) spectral normalization…

2024

Recurrent Reinforcement Learning with Memoroids

NeurIPS 2024poster

Memory models such as Recurrent Neural Networks (RNNs) and Transformers address Partially Observable Markov Decision Processes (POMDPs) by mapping trajectories to latent Markov states. Neither model scales particularly well to long sequences, especially compared to an emerging class of memory models…

2023

Discovering Evolution Strategies via Meta-Black-Box Optimization

ICLR 2023poster

Optimizing functions without access to gradients is the remit of black-box meth- ods such as evolution strategies. While highly general, their learning dynamics are often times heuristic and inflexible — exactly the limitations that meta-learning can address. Hence, we propose to discover effective…

2023

Discovering General Reinforcement Learning Algorithms with Adversarial Environment Design

NeurIPS 2023poster

The past decade has seen vast progress in deep reinforcement learning (RL) on the back of algorithms manually designed by human researchers. Recently, it has been shown that it is possible to meta-learn update rules, with the hope of discovering algorithms that can perform well on a wide range of RL…

2023

Structured State Space Models for In-Context Reinforcement Learning

NeurIPS 2023poster

Structured state space sequence (S4) models have recently achieved state-of-the-art performance on long-range sequence modeling tasks. These models also have fast inference speeds and parallelisable training, making them potentially useful in many reinforcement learning settings. We propose a modif…

2022

Discovered Policy Optimisation

NeurIPS 2022accept

Tremendous progress has been made in reinforcement learning (RL) over the past decade. Most of these advancements came through the continual development of new algorithms, which were designed using a combination of mathematical derivations, intuitions, and experimentation. Such an approach of creati…

Cited by 93SourcePDFScholar
2022

Proximal Learning With Opponent-Learning Awareness

NeurIPS 2022accept

Learning With Opponent-Learning Awareness (LOLA) (Foerster et al. [2018a]) is a multi-agent reinforcement learning algorithm that typically learns reciprocity-based cooperation in partially competitive environments. However, LOLA often fails to learn such behaviour on more complex policy spaces para…