Portrait de Emmanuel Bengio

Emmanuel Bengio

Membre industriel associé
Scientifique en apprentissage automatique, Recursion
Sujets de recherche
Apprentissage par renforcement
Apprentissage profond
GFlowNets
Modèles génératifs
Modélisation moléculaire

Biographie

Emmanuel Bengio est chercheur en ML à Valence Labs/Recursion, où il travaille sur l'intersection des GFlowNets et de la découverte de médicaments. Il a fait son doctorat sous la direction de Joelle Pineau et Doina Precup à McGill/Mila - Institut québécois d'intelligence artificielle, en se concentrant sur la compréhension de la généralisation dans la RL profonde.

Publications

QGFN: Controllable Greediness with Action Values
Generative Flow Networks (GFlowNets; GFNs) are a family of energy-based generative methods for combinatorial objects, capable of generating … (voir plus)diverse and high-utility samples. However, consistently biasing GFNs towards producing high-utility samples is non-trivial. In this work, we leverage connections between GFNs and reinforcement learning (RL) and propose to combine the GFN policy with an action-value estimate,
Amortizing intractable inference in diffusion models for vision, language, and control
Diffusion models have emerged as effective distribution estimators in vision, language, and reinforcement learning, but their use as priors … (voir plus)in downstream tasks poses an intractable posterior inference problem. This paper studies amortized sampling of the posterior over data,
Efficient Biological Data Acquisition through Inference Set Design
Ihor Neporozhnii
Jason Hartford
In drug discovery, highly automated high-throughput laboratories are used to screen a large number of compounds in search of effective drugs… (voir plus). These experiments are expensive, so one might hope to reduce their cost by only experimenting on a subset of the compounds, and predicting the outcomes of the remaining experiments. In this work, we model this scenario as a sequential subset selection problem: we aim to select the smallest set of candidates in order to achieve some desired level of accuracy for the system as a whole. Our key observation is that, if there is heterogeneity in the difficulty of the prediction problem across the input space, selectively obtaining the labels for the hardest examples in the acquisition pool will leave only the relatively easy examples to remain in the inference set, leading to better overall system performance. We call this mechanism inference set design, and propose the use of a confidence-based active learning solution to prune out these challenging examples. Our algorithm includes an explicit stopping criterion that interrupts the acquisition loop when it is sufficiently confident that the system has reached the target performance. Our empirical studies on image and molecular datasets, as well as a real-world large-scale biological assay, show that active learning for inference set design leads to significant reduction in experimental cost while retaining high system performance.
GFlowNet Pretraining with Inexpensive Rewards
Generative Flow Networks (GFlowNets), a class of generative models have recently emerged as a suitable framework for generating diverse and … (voir plus)high-quality molecular structures by learning from unnormalized reward distributions. Previous works in this direction often restrict exploration by using predefined molecular fragments as building blocks, limiting the chemical space that can be accessed. In this work, we introduce Atomic GFlowNets (A-GFNs), a foundational generative model leveraging individual atoms as building blocks to explore drug-like chemical space more comprehensively. We propose an unsupervised pre-training approach using offline drug-like molecule datasets, which conditions A-GFNs on inexpensive yet informative molecular descriptors such as drug-likeliness, topological polar surface area, and synthetic accessibility scores. These properties serve as proxy rewards, guiding A-GFNs towards regions of chemical space that exhibit desirable pharmacological properties. We further our method by implementing a goal-conditioned fine-tuning process, which adapts A-GFNs to optimize for specific target properties. In this work, we pretrain A-GFN on the ZINC15 offline dataset and employ robust evaluation metrics to show the effectiveness of our approach when compared to other relevant baseline methods in drug design.
Learning to Scale Logits for Temperature-Conditional GFlowNets
GFlowNets are probabilistic models that sequentially generate compositional structures through a stochastic policy. Among GFlowNets, tempera… (voir plus)ture-conditional GFlowNets can introduce temperature-based controllability for exploration and exploitation. We propose \textit{Logit-scaling GFlowNets} (Logit-GFN), a novel architectural design that greatly accelerates the training of temperature-conditional GFlowNets. It is based on the idea that previously proposed approaches introduced numerical challenges in the deep network training, since different temperatures may give rise to very different gradient profiles as well as magnitudes of the policy's logits. We find that the challenge is greatly reduced if a learned function of the temperature is used to scale the policy's logits directly. Also, using Logit-GFN, GFlowNets can be improved by having better generalization capabilities in offline learning and mode discovery capabilities in online learning, which is empirically verified in various biological and chemical tasks. Our code is available at https://github.com/dbsxodud-11/logit-gfn
Local Search GFlowNets
Generative Flow Networks (GFlowNets) are amortized sampling methods that learn a distribution over discrete objects proportional to their re… (voir plus)wards. GFlowNets exhibit a remarkable ability to generate diverse samples, yet occasionally struggle to consistently produce samples with high rewards due to over-exploration on wide sample space. This paper proposes to train GFlowNets with local search, which focuses on exploiting high-rewarded sample space to resolve this issue. Our main idea is to explore the local neighborhood via backtracking and reconstruction guided by backward and forward policies, respectively. This allows biasing the samples toward high-reward solutions, which is not possible for a typical GFlowNet solution generation scheme, which uses the forward policy to generate the solution from scratch. Extensive experiments demonstrate a remarkable performance improvement in several biochemical tasks. Source code is available: https://github.com/dbsxodud-11/ls_gfn.
Maximum entropy GFlowNets with soft Q-learning
Generative Flow Networks (GFNs) have emerged as a powerful tool for sampling discrete objects from unnormalized distributions, offering a sc… (voir plus)alable alternative to Markov Chain Monte Carlo (MCMC) methods. While GFNs draw inspiration from maximum entropy reinforcement learning (RL), the connection between the two has largely been unclear and seemingly applicable only in specific cases. This paper addresses the connection by constructing an appropriate reward function, thereby establishing an exact relationship between GFNs and maximum entropy RL. This construction allows us to introduce maximum entropy GFNs, which, in contrast to GFNs with uniform backward policy, achieve the maximum entropy attainable by GFNs without constraints on the state space.
Generative Active Learning for the Search of Small-Molecule Protein Binders
Cheng-Hao Liu
Éric Jolicoeur
Edward Ruediger
Andrei Nica
Daniel St-Cyr
Doris Alexandra Schuetz
Victor Ion Butoi
Saikrishna Gottipati
Prateek Gupta
Sasikanth Avancha
William Hamilton
Brooks Paige
Sanchit Misra
Bharat Kaul
José Miguel Hernández-Lobato
Marwin Segler
Michael Bronstein
Anne Marinier
Mike Tyers
Despite substantial progress in machine learning for scientific discovery in recent years, truly de novo design of small molecules which exh… (voir plus)ibit a property of interest remains a significant challenge. We introduce LambdaZero, a generative active learning approach to search for synthesizable molecules. Powered by deep reinforcement learning, LambdaZero learns to search over the vast space of molecules to discover candidates with a desired property. We apply LambdaZero with molecular docking to design novel small molecules that inhibit the enzyme soluble Epoxide Hydrolase 2 (sEH), while enforcing constraints on synthesizability and drug-likeliness. LambdaZero provides an exponential speedup in terms of the number of calls to the expensive molecular docking oracle, and LambdaZero de novo designed molecules reach docking scores that would otherwise require the virtual screening of a hundred billion molecules. Importantly, LambdaZero discovers novel scaffolds of synthesizable, drug-like inhibitors for sEH. In in vitro experimental validation, a series of ligands from a generated quinazoline-based scaffold were synthesized, and the lead inhibitor N-(4,6-di(pyrrolidin-1-yl)quinazolin-2-yl)-N-methylbenzamide (UM0152893) displayed sub-micromolar enzyme inhibition of sEH.
A community effort in SARS-CoV-2 drug discovery.
Johannes Schimunek
Philipp Seidl
Katarina Elez
Tim Hempel
Tuan Le
Frank Noé
Simon Olsson
Lluís Raich
Robin Winter
Hatice Gokcan
Filipp Gusev
Evgeny M. Gutkin
Olexandr Isayev
Maria G. Kurnikova
Chamali H. Narangoda
Roman Zubatyuk
Ivan P. Bosko
Konstantin V. Furs
Anna D. Karpenko
Yury V. Kornoushenko … (voir 133 de plus)
Mikita Shuldau
Artsemi Yushkevich
Mohammed B. Benabderrahmane
Patrick Bousquet‐Melou
Ronan Bureau
Beatrice Charton
Bertrand C. Cirou
Gérard Gil
William J. Allen
Suman Sirimulla
Stanley Watowich
Nick Antonopoulos
Nikolaos Epitropakis
Agamemnon Krasoulis
Vassilis Pitsikalis
Stavros Theodorakis
Igor Kozlovskii
Anton Maliutin
Alexander Medvedev
Petr Popov
Mark Zaretckii
Hamid Eghbal‐Zadeh
Christina Halmich
Sepp Hochreiter
Andreas Mayr
Peter Ruch
Michael Widrich
Francois Berenger
Ashutosh Kumar
Yoshihiro Yamanishi
Kam Y. J. Zhang
Moksh J. Jain
Cheng-Hao Liu
Gilles Marcou
M. Gilles
Enrico Glaab
Kelly Barnsley
Suhasini M. Iyengar
Mary Jo Ondrechen
V. Joachim Haupt
Florian Kaiser
Michael Schroeder
Luisa Pugliese
Simone Albani
Christina Athanasiou
Andrea Beccari
Paolo Carloni
Giulia D'Arrigo
Eleonora Gianquinto
Jonas Goßen
Anton Hanke
Benjamin P. Joseph
Daria B. Kokh
Sandra Kovachka
Candida Manelfi
Goutam Mukherjee
Abraham Muñiz‐Chicharro
Francesco Musiani
Ariane Nunes‐Alves
Giulia Paiardi
Giulia Rossetti
S. Kashif Sadiq
Francesca Spyrakis
Carmine Talarico
Alexandros Tsengenes
Rebecca C. Wade
Conner Copeland
Jeremiah Gaiser
Daniel R. Olson
Amitava Roy
Vishwesh Venkatraman
Travis J. Wheeler
Haribabu Arthanari
Klara Blaschitz
Marco Cespugli
Vedat Durmaz
Konstantin Fackeldey
Patrick D. Fischer
Christoph Gorgulla
Christian Gruber
Karl Gruber
Michael Hetmann
Jamie E. Kinney
Krishna M. Padmanabha Das
Shreya Pandita
Amit Singh
Georg Steinkellner
Guilhem Tesseyre
Gerhard Wagner
Zi‐Fu Wang
Ryan J. Yust
Dmitry S. Druzhilovskiy
Dmitry A. Filimonov
Pavel V. Pogodin
Vladimir Poroikov
Anastassia V. Rudik
Leonid A. Stolbov
Alexander V. Veselovsky
Maria De Rosa
Giada De Simone
Maria R. Gulotta
Jessica Lombino
Nedra Mekni
Ugo Perricone
Arturo Casini
Amanda Embree
D. Benjamin Gordon
David Lei
Katelin Pratt
Christopher A. Voigt
Kuang‐Yu Chen
Yves Jacob
Tim Krischuns
Pierre Lafaye
Agnès Zettor
M. Luis Rodríguez
Kris M. White
Daren Fearon
Frank Von Delft
Martin A. Walsh
Dragos Horvath
Charles L. Brooks
Babak Falsafi
Bryan Ford
Adolfo García‐Sastre
Sang Yup Lee
Nadia Naffakh
Alexandre Varnek
Günter Klambauer
Thomas M. Hermans
The COVID-19 pandemic continues to pose a substantial threat to human lives and is likely to do so for years to come. Despite the availabili… (voir plus)ty of vaccines, searching for efficient small-molecule drugs that are widely available, including in low- and middle-income countries, is an ongoing challenge. In this work, we report the results of an open science community effort, the "Billion molecules against Covid-19 challenge", to identify small-molecule inhibitors against SARS-CoV-2 or relevant human receptors. Participating teams used a wide variety of computational methods to screen a minimum of 1 billion virtual molecules against 6 protein targets. Overall, 31 teams participated, and they suggested a total of 639,024 molecules, which were subsequently ranked to find 'consensus compounds'. The organizing team coordinated with various contract research organizations (CROs) and collaborating institutions to synthesize and test 878 compounds for biological activity against proteases (Nsp5, Nsp3, TMPRSS2), nucleocapsid N, RdRP (only the Nsp12 domain), and (alpha) spike protein S. Overall, 27 compounds with weak inhibition/binding were experimentally identified by binding-, cleavage-, and/or viral suppression assays and are presented here. Open science approaches such as the one presented here contribute to the knowledge base of future drug discovery efforts in finding better SARS-CoV-2 treatments.
Baking Symmetry into GFlowNets
GFlowNets have exhibited promising performance in generating diverse candidates with high rewards. These networks generate objects increment… (voir plus)ally and aim to learn a policy that assigns probability of sampling objects in proportion to rewards. However, the current training pipelines of GFlowNets do not consider the presence of isomorphic actions, which are actions resulting in symmetric or isomorphic states. This lack of symmetry increases the amount of samples required for training GFlowNets and can result in inefficient and potentially incorrect flow functions. As a consequence, the reward and diversity of the generated objects decrease. In this study, our objective is to integrate symmetries into GFlowNets by identifying equivalent actions during the generation process. Experimental results using synthetic data demonstrate the promising performance of our proposed approaches.
DGFN: Double Generative Flow Networks
Learning GFlowNets From Partial Episodes For Improved Convergence And Stability
Generative flow networks (GFlowNets) are a family of algorithms for training a sequential sampler of discrete objects under an unnormalized … (voir plus)target density and have been successfully used for various probabilistic modeling tasks. Existing training objectives for GFlowNets are either local to states or transitions, or propagate a reward signal over an entire sampling trajectory. We argue that these alternatives represent opposite ends of a gradient bias-variance tradeoff and propose a way to exploit this tradeoff to mitigate its harmful effects. Inspired by the TD(