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Structured State Space Models for In-Context Reinforcement Learning
Christopher Lu · Yannick Schroecker · Albert Gu · Emilio Parisotto · Jakob Foerster · Satinder Singh · Feryal Behbahani
Event URL: https://openreview.net/forum?id=CKPTz21e6k »

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 modification to a variant of S4 that enables us to initialise and reset the hidden state in parallel, allowing us to tackle reinforcement learning tasks. We show that our modified architecture runs asymptotically faster than Transformers and performs better than LSTM models on a simple memory-based task. Then, by leveraging the model’s ability to handle long-range sequences, we achieve strong performance on a challenging meta-learning task in which the agent is given a randomly-sampled continuous control environment, combined with a randomly-sampled linear projection of the environment's observations and actions. Furthermore, we show the resulting model can adapt to out-of-distribution held-out tasks. Overall, the results presented in this paper suggest that the S4 models are a strong contender for the default architecture used for in-context reinforcement learning.

Author Information

Christopher Lu (University of Oxford)
Yannick Schroecker (DeepMind)
Albert Gu (Carnegie Mellon University, DeepMind)
Emilio Parisotto (Carnegie Mellon University)
Jakob Foerster (Oxford university)
Jakob Foerster

Jakob Foerster started as an Associate Professor at the department of engineering science at the University of Oxford in the fall of 2021. During his PhD at Oxford he helped bring deep multi-agent reinforcement learning to the forefront of AI research and interned at Google Brain, OpenAI, and DeepMind. After his PhD he worked as a research scientist at Facebook AI Research in California, where he continued doing foundational work. He was the lead organizer of the first Emergent Communication workshop at NeurIPS in 2017, which he has helped organize ever since and was awarded a prestigious CIFAR AI chair in 2019. His past work addresses how AI agents can learn to cooperate and communicate with other agents, most recently he has been developing and addressing the zero-shot coordination problem setting, a crucial step towards human-AI coordination.

Satinder Singh (DeepMind)
Feryal Behbahani (Google DeepMind)

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