Marc Gendron-Bellemare

Pierluca D'Oro

Doctorat - UdeM

Superviseur⋅e principal⋅e :

Doctorat - McGill

Co-superviseur⋅e :

Nate Rahn

Doctorat - McGill

Co-superviseur⋅e :

Doina Precup

Max Schwarzer

Doctorat - UdeM

Superviseur⋅e principal⋅e :

Harley Wiltzer

Doctorat - McGill

Superviseur⋅e principal⋅e :

Publications

Bootstrapped Representations in Reinforcement Learning

Charline Le Lan

Stephen Tu

Mark Rowland

Anna Harutyunyan

Rishabh Agarwal

Will Dabney

In reinforcement learning (RL), state representations are key to dealing with large or continuous state spaces. While one of the promises of… (voir plus) deep learning algorithms is to automatically construct features well-tuned for the task they try to solve, such a representation might not emerge from end-to-end training of deep RL agents. To mitigate this issue, auxiliary objectives are often incorporated into the learning process and help shape the learnt state representation. Bootstrapping methods are today's method of choice to make these additional predictions. Yet, it is unclear which features these algorithms capture and how they relate to those from other auxiliary-task-based approaches. In this paper, we address this gap and provide a theoretical characterization of the state representation learnt by temporal difference learning (Sutton, 1988). Surprisingly, we find that this representation differs from the features learned by Monte Carlo and residual gradient algorithms for most transition structures of the environment in the policy evaluation setting. We describe the efficacy of these representations for policy evaluation, and use our theoretical analysis to design new auxiliary learning rules. We complement our theoretical results with an empirical comparison of these learning rules for different cumulant functions on classic domains such as the four-room domain (Sutton et al, 1999) and Mountain Car (Moore, 1990).

2023-07-03

Proceedings of the 40th International Conference on Machine Learning (publié)

A Novel Stochastic Gradient Descent Algorithm for LearningPrincipal Subspaces

Charline Le Lan

Joshua Greaves

Jesse Farebrother

Mark Rowland

Fabian Pedregosa

Rishabh Agarwal

In this paper, we derive an algorithm that learns a principal subspace from sample entries, can be applied when the approximate subspace i… (voir plus)s represented by a neural network, and hence can bescaled to datasets with an effectively infinite number of rows and columns. Our method consistsin defining a loss function whose minimizer is the desired principal subspace, and constructing agradient estimate of this loss whose bias can be controlled.

2023-04-11

Proceedings of The 26th International Conference on Artificial Intelligence and Statistics (publié)

Investigating Multi-task Pretraining and Generalization in Reinforcement Learning

Adrien Ali Taiga

Rishabh Agarwal

Jesse Farebrother

Google Brain

2023-02-01

ICLR.cc/2023/Conference (poster)

Proto-Value Networks: Scaling Representation Learning with Auxiliary Tasks

Jesse Farebrother

Joshua Greaves

Rishabh Agarwal

Charline Le Lan

Ross Goroshin

Auxiliary tasks improve the representations learned by deep reinforcement learning agents. Analytically, their effect is reasonably well-und… (voir plus)erstood; in practice, how-ever, their primary use remains in support of a main learning objective, rather than as a method for learning representations. This is perhaps surprising given that many auxiliary tasks are defined procedurally, and hence can be treated as an essentially infinite source of information about the environment. Based on this observation, we study the effectiveness of auxiliary tasks for learning rich representations, focusing on the setting where the number of tasks and the size of the agent’s network are simultaneously increased. For this purpose, we derive a new family of auxiliary tasks based on the successor measure. These tasks are easy to implement and have appealing theoretical properties. Combined with a suitable off-policy learning rule, the result is a representation learning algorithm that can be understood as extending Mahadevan & Maggioni (2007)’s proto-value functions to deep reinforcement learning – accordingly, we call the resulting object proto-value networks. Through a series of experiments on the Arcade Learning Environment, we demonstrate that proto-value networks produce rich features that may be used to obtain performance comparable to established algorithms, using only linear approximation and a small number (~4M) of interactions with the environment’s reward function.

2023-02-01

ICLR.cc/2023/Conference (poster)

Sample-Efficient Reinforcement Learning by Breaking the Replay Ratio Barrier

Pierluca D'Oro

Max Schwarzer

Evgenii Nikishin

Pierre-Luc Bacon

Increasing the replay ratio, the number of updates of an agent's parameters per environment interaction, is an appealing strategy for improv… (voir plus)ing the sample efficiency of deep reinforcement learning algorithms. In this work, we show that fully or partially resetting the parameters of deep reinforcement learning agents causes better replay ratio scaling capabilities to emerge. We push the limits of the sample efficiency of carefully-modified algorithms by training them using an order of magnitude more updates than usual, significantly improving their performance in the Atari 100k and DeepMind Control Suite benchmarks. We then provide an analysis of the design choices required for favorable replay ratio scaling to be possible and discuss inherent limits and tradeoffs.

2023-02-01

ICLR.cc/2023/Conference (notable)

Bigger, Better, Faster: Human-level Atari with human-level efficiency

Max Schwarzer

Johan Samir Obando Ceron

Rishabh Agarwal

We introduce a value-based RL agent, which we call BBF, that achieves super-human performance in the Atari 100K benchmark. BBF relies on sca… (voir plus)ling the neural networks used for value estimation, as well as a number of other design choices that enable this scaling in a sample-efficient manner. We conduct extensive analyses of these design choices and provide insights for future work. We end with a discussion about updating the goalposts for sample-efficient RL research on the ALE. We make our code and data publicly available at https://github.com/google-research/google-research/tree/master/bigger_better_faster.

2023-01-01

ICML (publié)

The Small Batch Size Anomaly in Multistep Deep Reinforcement Learning

Johan Samir Obando Ceron

2023-01-01

Tiny Papers @ ICLR (published)

The Statistical Benefits of Quantile Temporal-Difference Learning for Value Estimation

Mark Rowland

Yunhao Tang

Clare Lyle

Remi Munos

Will Dabney

We study the problem of temporal-difference-based policy evaluation in reinforcement learning. In particular, we analyse the use of a distri… (voir plus)butional reinforcement learning algorithm, quantile temporal-difference learning (QTD), for this task. We reach the surprising conclusion that even if a practitioner has no interest in the return distribution beyond the mean, QTD (which learns predictions about the full distribution of returns) may offer performance superior to approaches such as classical TD learning, which predict only the mean return, even in the tabular setting.

2023-01-01

ICML (publié)

The Statistical Benefits of Quantile Temporal-Difference Learning for Value Estimation

Mark Rowland

Yunhao Tang

Clare Lyle

Remi Munos

Will Dabney

2023-01-01

ICML (publié)

Variance Double-Down: The Small Batch Size Anomaly in Multistep Deep Reinforcement Learning

Johan Samir Obando Ceron

In deep reinforcement learning, multi-step learning is almost unavoidable to achieve state-of-the-art performance. However, the increased va… (voir plus)riance that multistep learning brings makes it difficult to increase the update horizon beyond relatively small numbers. In this paper, we report the counterintuitive finding that decreasing the batch size parameter improves the performance of many standard deep RL agents that use multi-step learning. It is well-known that gradient variance decreases with increasing batch sizes, so obtaining improved performance by increasing variance on two fronts is a rather surprising finding. We conduct a broad set of experiments to better understand what we call the variance doubledown phenomenon.

2022-12-09

NeurIPS.cc/2022/Workshop/DeepRL (inconnu)