Doina Precup

busra-tugce.gurbuz@mila.quebec

Jesse Farebrother

Doctorat - McGill

Superviseur⋅e principal⋅e :

Marc Gendron-Bellemare

Doctorat - McGill

Superviseur⋅e principal⋅e :

Eilif B. Muller

Mohammad Sami Nur Islam Islam

Jonathan Hu

Maîtrise recherche - McGill

jonathan.hu@mila.quebec

Howard Huang

Doctorat - McGill

huanghow@mila.quebec

Maîtrise recherche - McGill

mohammad-sami-nur.islam@mila.quebec

Hangzhan Jin

Doctorat - Polytechnique

jinhangzhan@gmail.com

flemming.kondrup@mila.quebec

Flemming Kondrup

Postdoctorat - McGill

Jonathan Lebensold

Collaborateur·rice alumni - McGill

Collaborateur·rice alumni - McGill

jeremy.lucas@mila.quebec

Ray Luo

Doctorat - McGill

Superviseur⋅e principal⋅e :

Xujie Si

luo.ziyan@mila.quebec

Sicheng Lyu

Maîtrise recherche - McGill

sicheng.lyu@mila.quebec

G McCracken

Doctorat - McGill

mccrackg@mila.quebec

shahrad.mohammadzadeh@mila.quebec

Shahrad Mohammadzadeh

Maîtrise recherche - McGill

Superviseur⋅e principal⋅e :

Reihaneh Rabbany

padideh.nouri@mila.quebec

Gabriela Moisescu-Pareja

Collaborateur·rice de recherche - McGill

Co-superviseur⋅e :

Irina Rish

moisescg@mila.quebec

Padideh Nouri

Doctorat - UdeM

Doctorat - McGill

Co-superviseur⋅e :

Stagiaire de recherche - McGill

william.potter@mila.quebec

manoosh.samiei@mila.quebec

Nate Rahn

Doctorat - McGill

Superviseur⋅e principal⋅e :

Marc Gendron-Bellemare

nathan.rahn@mila.quebec

Mandana Samiei

Doctorat - McGill

Co-superviseur⋅e :

Blake Richards

samiemandana@gmail.com

Doctorat - McGill

Co-superviseur⋅e :

Paul Masset

Doctorat - McGill

Nishanth Anand Vemgal

Doctorat - McGill

Doctorat - McGill

Co-superviseur⋅e :

Samira Ebrahimi Kahou

Zihan Wang

Doctorat - McGill

zihan.wang@mila.quebec

guangyuan.wang@mila.quebec

Guangyuan Wang

Stagiaire de recherche - McGill

Steve Wen

Maîtrise recherche - McGill

Co-superviseur⋅e :

Gregory Dudek

steve.wen@mila.quebec

Zijing Wu

Doctorat - McGill

Superviseur⋅e principal⋅e :

Paul Masset

zijing.wu@mila.quebec

Doctorat - McGill

shuyuan.zhang@mila.quebec

Harry Zhao

Collaborateur·rice alumni - McGill

Co-superviseur⋅e :

Billets de blogue

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22 février 2024

Skipper : combiner l’abstraction spatiale et temporelle afin d’améliorer la généralisation

par

Mingde Harry Zhao

Safa Alver

Harm van Seijen

Romain Laroche

Doina Precup

Yoshua Bengio

Lire l'article

Publications

Towards Painless Policy Optimization for Constrained MDPs

Arushi Jain

Sharan Vaswani

Reza Babanezhad Harikandeh

Csaba Szepesvari

We study policy optimization in an infinite horizon, …

2022-08-16

Proceedings of the Thirty-Eighth Conference on Uncertainty in Artificial Intelligence (publié)

Automated prediction of extubation success in extremely preterm infants: the APEX multicenter study

Lara J. Kanbar

Wissam Shalish

Charles C. Onu

Samantha Latremouille

Lajos Kovacs

Martin Keszler

Sanjay Chawla

Karen A. Brown

Robert E. Kearney

Guilherme M. Sant’Anna

2022-07-28

Pediatric Research (publié)

On the Expressivity of Markov Reward (Extended Abstract)

David Abel

Will Dabney

Anna Harutyunyan

Mark K. Ho

Michael L. Littman

Satinder Singh

2022-07-22

Proceedings of the Thirty-First International Joint Conference on Artificial Intelligence (publié)

Why Should I Trust You, Bellman? The Bellman Error is a Poor Replacement for Value Error

Scott Fujimoto

David Meger

Ofir Nachum

Shixiang Shane Gu

In this work, we study the use of the Bellman equation as a surrogate objective for value prediction accuracy. While the Bellman equation is… (voir plus) uniquely solved by the true value function over all state-action pairs, we find that the Bellman error (the difference between both sides of the equation) is a poor proxy for the accuracy of the value function. In particular, we show that (1) due to cancellations from both sides of the Bellman equation, the magnitude of the Bellman error is only weakly related to the distance to the true value function, even when considering all state-action pairs, and (2) in the finite data regime, the Bellman equation can be satisfied exactly by infinitely many suboptimal solutions. This means that the Bellman error can be minimized without improving the accuracy of the value function. We demonstrate these phenomena through a series of propositions, illustrative toy examples, and empirical analysis in standard benchmark domains.

2022-07-18

International Conference on Machine Learning (Accept for Short Presentation)

Improving Robustness against Real-World and Worst-Case Distribution Shifts through Decision Region Quantification

Leo Schwinn

Leon Bungert

A. Nguyen

Ren'e Raab

Falk Pulsmeyer

B. Eskofier

Dario Zanca

The reliability of neural networks is essential for their use in safety-critical applications. Existing approaches generally aim at improvin… (voir plus)g the robustness of neural networks to either real-world distribution shifts (e.g., common corruptions and perturbations, spatial transformations, and natural adversarial examples) or worst-case distribution shifts (e.g., optimized adversarial examples). In this work, we propose the Decision Region Quantification (DRQ) algorithm to improve the robustness of any differentiable pre-trained model against both real-world and worst-case distribution shifts in the data. DRQ analyzes the robustness of local decision regions in the vicinity of a given data point to make more reliable predictions. We theoretically motivate the DRQ algorithm by showing that it effectively smooths spurious local extrema in the decision surface. Furthermore, we propose an implementation using targeted and untargeted adversarial attacks. An extensive empirical evaluation shows that DRQ increases the robustness of adversarially and non-adversarially trained models against real-world and worst-case distribution shifts on several computer vision benchmark datasets.

2022-06-27

Proceedings of the 39th International Conference on Machine Learning (publié)

Proving Theorems using Incremental Learning and Hindsight Experience Replay

Maxwell Crouse

Eser Aygün

Laurent Orseau

Bassem Makni

Vernon Ralph Austel

Ankit Anand

Xavier Glorot

Cristina Cornelio

Shajith Ikbal

Stephen McAleer

Vlad Firoiu

Pavan Kapanipathi

Lei Zhang

Ndivhuwo Makondo

Shibl Mourad

Traditional automated theorem provers for first-order logic depend on speed-optimized search and many handcrafted heuristics that are design… (voir plus)ed to work best over a wide range of domains. Machine learning approaches in literature either depend on these traditional provers to bootstrap themselves or fall short on reaching comparable performance. In this paper, we propose a general incremental learning algorithm for training domain specific provers for first-order logic without equality, based only on a basic given-clause algorithm, but using a learned clause-scoring function. Clauses are represented as graphs and presented to transformer networks with spectral features. To address the sparsity and the initial lack of training data as well as the lack of a natural curriculum, we adapt hindsight experience replay to theorem proving, so as to be able to learn even when no proof can be found. We show that provers trained this way can match and sometimes surpass state-of-the-art traditional provers on the TPTP dataset in terms of both quantity and quality of the proofs.

2022-06-27

Proceedings of the 39th International Conference on Machine Learning (publié)

Deep Learning Prediction of Response to Disease Modifying Therapy in Primary Progressive Multiple Sclerosis (P1-1.Virtual)

Jean-Pierre René Falet

Joshua Durso-finley

Brennan Nichyporuk

Julien Schroeter

Francesca Bovis

Maria-Pia Sormani

Tal Arbel

Douglas Arnold

2022-05-02

Neurology (inconnu)

Don't Freeze Your Embedding: Lessons from Policy Finetuning in Environment Transfer

Victoria Dean

Daniel Toyama

A common occurrence in reinforcement learning (RL) research is making use of a pretrained vision stack that converts image observations to l… (voir plus)atent vectors. Using a visual embedding in this way leaves open questions, though: should the vision stack be updated with the policy? In this work, we evaluate the effectiveness of such decisions in RL transfer settings. We introduce policy update formulations for use after pretraining in a different environment and analyze the performance of such formulations. Through this evaluation, we also detail emergent metrics of benchmark suites and present results on Atari and AndroidEnv.

2022-04-26

ICLR.cc/2022/Workshop/GPL (poster)

openreview.net

Constructing a Good Behavior Basis for Transfer Using Generalized Policy Updates

Safa Alver

We study the problem of learning a good set of policies, so that when combined together, they can solve a wide variety of unseen reinforceme… (voir plus)nt learning tasks with no or very little new data. Specifically, we consider the framework of generalized policy evaluation and improvement, in which the rewards for all tasks of interest are assumed to be expressible as a linear combination of a fixed set of features. We show theoretically that, under certain assumptions, having access to a specific set of diverse policies, which we call a set of independent policies, can allow for instantaneously achieving high-level performance on all possible downstream tasks which are typically more complex than the ones on which the agent was trained. Based on this theoretical analysis, we propose a simple algorithm that iteratively constructs this set of policies. In addition to empirically validating our theoretical results, we compare our approach with recently proposed diverse policy set construction methods and show that, while others fail, our approach is able to build a behavior basis that enables instantaneous transfer to all possible downstream tasks. We also show empirically that having access to a set of independent policies can better bootstrap the learning process on downstream tasks where the new reward function cannot be described as a linear combination of the features. Finally, we demonstrate how this policy set can be useful in a lifelong reinforcement learning setting.

2022-04-24

International Conference on Learning Representations (Accept (Poster))

openreview.net

Policy Gradients Incorporating the Future

David Venuto

Elaine Lau

Ofir Nachum

Reasoning about the future -- understanding how decisions in the present time affect outcomes in the future -- is one of the central challen… (voir plus)ges for reinforcement learning (RL), especially in highly-stochastic or partially observable environments. While predicting the future directly is hard, in this work we introduce a method that allows an agent to "look into the future" without explicitly predicting it. Namely, we propose to allow an agent, during its training on past experience, to observe what \emph{actually} happened in the future at that time, while enforcing an information bottleneck to avoid the agent overly relying on this privileged information. This gives our agent the opportunity to utilize rich and useful information about the future trajectory dynamics in addition to the present. Our method, Policy Gradients Incorporating the Future (PGIF), is easy to implement and versatile, being applicable to virtually any policy gradient algorithm. We apply our proposed method to a number of off-the-shelf RL algorithms and show that PGIF is able to achieve higher reward faster in a variety of online and offline RL domains, as well as sparse-reward and partially observable environments.

2022-04-24

International Conference on Learning Representations (Accept (Poster))

openreview.net

Learning how to Interact with a Complex Interface using Hierarchical Reinforcement Learning

Gheorghe Comanici

Amelia Glaese

Anita Gergely

Daniel Toyama

Zafarali Ahmed

Tyler Jackson

Philippe Hamel

Hierarchical Reinforcement Learning (HRL) allows interactive agents to decompose complex problems into a hierarchy of sub-tasks. Higher-leve… (voir plus)l tasks can invoke the solutions of lower-level tasks as if they were primitive actions. In this work, we study the utility of hierarchical decompositions for learning an appropriate way to interact with a complex interface. Specifically, we train HRL agents that can interface with applications in a simulated Android device. We introduce a Hierarchical Distributed Deep Reinforcement Learning architecture that learns (1) subtasks corresponding to simple finger gestures, and (2) how to combine these gestures to solve several Android tasks. Our approach relies on goal conditioning and can be used more generally to convert any base RL agent into an HRL agent. We use the AndroidEnv environment to evaluate our approach. For the experiments, the HRL agent uses a distributed version of the popular DQN algorithm to train different components of the hierarchy. While the native action space is completely intractable for simple DQN agents, our architecture can be used to establish an effective way to interact with different tasks, significantly improving the performance of the same DQN agent over different levels of abstraction.

2022-04-20

ArXiv (prépublication)