← Search

Gauthier Gidel

63 accepted papers

2026

A Coin Flip for Safety: LLM Judges Fail to Reliably Measure Adversarial Robustness

ICML 2026poster

Automated \enquote{LLM-as-a-Judge} frameworks have become the de facto standard for scalable evaluation across natural language processing. For instance, in safety evaluation, these judges are relied upon to evaluate harmfulness in order to benchmark the robustness of safety against adversarial atta…

Cited by 0SourceScholar
2026

Accelerated and Stable Convergence with Anchored Generalized Optimistic Method

ICML 2026poster

We study first-order methods for solving monotone variational inequalities arising in min-max optimization. Classical approaches such as the extragradient method rely on two gradient queries per iteration, which limits their analysis and applicability in the online and stochastic settings. We propos…

Cited by 0SourceScholar
2026

Discrete Compositional Generation via General Soft Operators and Robust Reinforcement Learning

ICLR 2026poster

A major bottleneck in scientific discovery consists of narrowing an exponentially large set of objects, such as proteins or molecules, to a small set of promising candidates with desirable properties. While this process can rely on expert knowledge, recent methods leverage reinforcement learning (RL…

Cited by 0SourceScholar
2026

Position: LLM-Safety Evaluations Lack Robustness

ICML 2026poster

In this position paper, we argue that current safety alignment research efforts for large language models are hindered by many intertwined sources of noise, such as small datasets, methodological inconsistencies, and unreliable evaluation setups. This can, at times, make it impossible to evaluate an…

Cited by 0SourceScholar
2025

Advantage Alignment Algorithms

ICLR 2025oral

Artificially intelligent agents are increasingly being integrated into human decision-making: from large language model (LLM) assistants to autonomous vehicles. These systems often optimize their individual objective, leading to conflicts, particularly in general-sum games where naive reinforcement…

Cited by 0SourcePDFScholar
2025

Dimension-adapted Momentum Outscales SGD

NeurIPS 2025spotlight

We investigate scaling laws for stochastic momentum algorithms on the power law random features model, parameterized by data complexity, target complexity, and model size. When trained with a stochastic momentum algorithm, our analysis reveals four distinct loss curve shapes determined by varying da…

Cited by 0SourceScholar
2025

Learning Diverse Attacks on Large Language Models for Robust Red-Teaming and Safety Tuning

ICLR 2025poster

Red-teaming, or identifying prompts that elicit harmful responses, is a critical step in ensuring the safe and responsible deployment of large language models (LLMs). Developing effective protection against many modes of attack prompts requires discovering diverse attacks. Automated red-teaming typi…

2025

Performative Prediction on Games and Mechanism Design

AISTATS 2025poster

Agents often have individual goals which depend on a group's actions. If agents trust a forecast of collective action and adapt strategically, such prediction can influence outcomes non-trivially, resulting in a form of performative prediction. This effect is ubiquitous in scenarios ranging from pan…

Cited by 0SourcecodeScholar
2025

Self-Play $Q$-Learners Can Provably Collude in the Iterated Prisoner's Dilemma

ICML 2025poster

A growing body of computational studies shows that simple machine learning agents converge to cooperative behaviors in social dilemmas, such as collusive price-setting in oligopoly markets, raising questions about what drives this outcome. In this work, we provide theoretical foundations for this ph…

Cited by 0SourcePDFScholar
2025

Solving hidden monotone variational inequalities with surrogate losses

ICLR 2025poster

Deep learning has proven to be effective in a wide variety of loss minimization problems. However, many applications of interest, like minimizing projected Bellman error and min-max optimization, cannot be modelled as minimizing a scalar loss function but instead correspond to solving a variational…

Cited by 1SourcePDFScholar
2025

Tight Lower Bounds and Improved Convergence in Performative Prediction

NeurIPS 2025poster

Performative prediction is a framework accounting for the shift in the data distribution induced by the prediction of a model deployed in the real world. Ensuring convergence to a stable solution—one at which the post‑deployment data distribution no longer changes—is crucial in settings where model…

Cited by 0SourcecodeScholar
2024

A Persuasive Approach to Combating Misinformation

ICML 2024poster

Bayesian Persuasion is proposed as a tool for social media platforms to combat the spread of misinformation. Since platforms can use machine learning to predict the popularity and misinformation features of to-be-shared posts, and users are largely motivated to share popular content, platforms can s…

Cited by 2SourcePDFScholar
2024

Efficient Adversarial Training in LLMs with Continuous Attacks

NeurIPS 2024spotlight

Large language models (LLMs) are vulnerable to adversarial attacks that can bypass their safety guardrails. In many domains, adversarial training has proven to be one of the most promising methods to reliably improve robustness against such attacks. Yet, in the context of LLMs, current methods for a…

2024

Expected flow networks in stochastic environments and two-player zero-sum games

ICLR 2024poster

Generative flow networks (GFlowNets) are sequential sampling models trained to match a given distribution. GFlowNets have been successfully applied to various structured object generation tasks, sampling a diverse set of high-reward objects quickly. We propose expected flow networks (EFlowNets), whi…

2024

High-Probability Convergence for Composite and Distributed Stochastic Minimization and Variational Inequalities with Heavy-Tailed Noise

ICML 2024oral

High-probability analysis of stochastic first-order optimization methods under mild assumptions on the noise has been gaining a lot of attention in recent years. Typically, gradient clipping is one of the key algorithmic ingredients to derive good high-probability guarantees when the noise is heavy-…

Cited by 18SourcePDFScholar
2024

Iterated Denoising Energy Matching for Sampling from Boltzmann Densities

ICML 2024poster

Efficiently generating statistically independent samples from an unnormalized probability distribution, such as equilibrium samples of many-body systems, is a foundational problem in science. In this paper, we propose Iterated Denoising Energy Matching (iDEM), an iterative algorithm that uses a nove…

2024

Local Linearity is All You Need (in Data-Driven Teleoperation)

IROS 2024poster

One of the critical aspects of assistive robotics is to provide a control system of a high-dimensional robot from a low-dimensional user input (i.e. a 2D joystick). Data-driven teleoperation seeks to provide an intuitive user interface called an action map to map the low dimensional input to robot v…

Cited by 0SourceScholar
2024

On the Scalability of Certified Adversarial Robustness with Generated Data

NeurIPS 2024poster

Certified defenses against adversarial attacks offer formal guarantees on the robustness of a model, making them more reliable than empirical methods such as adversarial training, whose effectiveness is often later reduced by unseen attacks. Still, the limited certified robustness that is currently…

Cited by 0SourcePDFScholar
2024

On the Stability of Iterative Retraining of Generative Models on their own Data

ICLR 2024spotlight

Deep generative models have made tremendous progress in modeling complex data, often exhibiting generation quality that surpasses a typical human's ability to discern the authenticity of samples. Undeniably, a key driver of this success is enabled by the massive amounts of web-scale data consumed by…

2024

Proving Linear Mode Connectivity of Neural Networks via Optimal Transport

AISTATS 2024poster

The energy landscape of high-dimensional non-convex optimization problems is crucial to understanding the effectiveness of modern deep neural network architectures. Recent works have experimentally shown that two different solutions found after two runs of a stochastic training are often connected b…

2024

Sarah Frank-Wolfe: Methods for Constrained Optimization with Best Rates and Practical Features

ICML 2024poster

The Frank-Wolfe (FW) method is a popular approach for solving optimization problems with structured constraints that arise in machine learning applications. In recent years, stochastic versions of FW have gained popularity, motivated by large datasets for which the computation of the full gradient i…

Cited by 8SourcePDFScholar
2024

Self-Consuming Generative Models with Curated Data Provably Optimize Human Preferences

NeurIPS 2024spotlight

The rapid progress in generative models has resulted in impressive leaps in generation quality, blurring the lines between synthetic and real data. Web-scale datasets are now prone to the inevitable contamination by synthetic data, directly impacting the training of future generated models. Alre…

Cited by 9SourcePDFScholar
2024

Soft Prompt Threats: Attacking Safety Alignment and Unlearning in Open-Source LLMs through the Embedding Space

NeurIPS 2024poster

Current research in adversarial robustness of LLMs focuses on \textit{discrete} input manipulations in the natural language space, which can be directly transferred to \textit{closed-source} models. However, this approach neglects the steady progression of \textit{open-source} models. As open-source…

2024

Stochastic Frank-Wolfe: Unified Analysis and Zoo of Special Cases

AISTATS 2024poster

The Conditional Gradient (or Frank-Wolfe) method is one of the most well-known methods for solving constrained optimization problems appearing in various machine learning tasks. The simplicity of iteration and applicability to many practical problems helped the method to gain popularity in the commu…

Cited by 4SourcePDFScholar
2024

Synaptic Weight Distributions Depend on the Geometry of Plasticity

ICLR 2024spotlight

A growing literature in computational neuroscience leverages gradient descent and learning algorithms that approximate it to study synaptic plasticity in the brain. However, the vast majority of this work ignores a critical underlying assumption: the choice of distance for synaptic changes - i.e. th…

2023

A General Framework For Proving The Equivariant Strong Lottery Ticket Hypothesis

ICLR 2023poster

The Strong Lottery Ticket Hypothesis (SLTH) stipulates the existence of a subnetwork within a sufficiently overparameterized (dense) neural network that---when initialized randomly and without any training---achieves the accuracy of a fully trained target network. Recent works by Da Cunha et. al 202…

Cited by 18SourcePDFScholar
2023

Convergence of Proximal Point and Extragradient-Based Methods Beyond Monotonicity: the Case of Negative Comonotonicity

ICML 2023poster

Algorithms for min-max optimization and variational inequalities are often studied under monotonicity assumptions. Motivated by non-monotone machine learning applications, we follow the line of works (Diakonikolas et al., 2021; Lee & Kim, 2021; Pethick et al., 2022; Bohm,2022) aiming at going beyond…

2023

Feature Likelihood Divergence: Evaluating the Generalization of Generative Models Using Samples

NeurIPS 2023poster

The past few years have seen impressive progress in the development of deep generative models capable of producing high-dimensional, complex, and photo-realistic data. However, current methods for evaluating such models remain incomplete: standard likelihood-based metrics do not always apply and rar…

2023

High-Probability Bounds for Stochastic Optimization and Variational Inequalities: the Case of Unbounded Variance

ICML 2023poster

During the recent years the interest of optimization and machine learning communities in high-probability convergence of stochastic optimization methods has been growing. One of the main reasons for this is that high-probability complexity bounds are more accurate and less studied than in-expectatio…

Cited by 58SourcePDFScholar
2023

Nesterov Meets Optimism: Rate-Optimal Separable Minimax Optimization

ICML 2023poster

We propose a new first-order optimization algorithm --- AcceleratedGradient-OptimisticGradient (AG-OG) Descent Ascent---for separable convex-concave minimax optimization. The main idea of our algorithm is to carefully leverage the structure of the minimax problem, performing Nesterov acceleration on…

Cited by 9SourcePDFScholar
2023

On the Limitations of the Elo, Real-World Games are Transitive, not Additive

AISTATS 2023poster

The Elo score has been extensively used to rank players by their skill or strength in competitive games such as chess, go, or StarCraft II. The Elo score implicitly assumes games have a strong additive—hence transitive—component. In this paper, we investigate the challenge of identifying transitive…

Cited by 28SourcePDFScholar
2023

Optimal Extragradient-Based Algorithms for Stochastic Variational Inequalities with Separable Structure

NeurIPS 2023poster

We consider the problem of solving stochastic monotone variational inequalities with a separable structure using a stochastic first-order oracle. Building on standard extragradient for variational inequalities we propose a novel algorithm---stochastic \emph{accelerated gradient-extragradient} (AG-EG…

Cited by 1SourcePDFScholar
2023

Variance Reduction is an Antidote to Byzantines: Better Rates, Weaker Assumptions and Communication Compression as a Cherry on the Top

ICLR 2023poster

Byzantine-robustness has been gaining a lot of attention due to the growth of the interest in collaborative and federated learning. However, many fruitful directions, such as the usage of variance reduction for achieving robustness and communication compression for reducing communication costs, rema…

2022

Beyond L1: Faster and Better Sparse Models with skglm

NeurIPS 2022accept

We propose a new fast algorithm to estimate any sparse generalized linear model with convex or non-convex separable penalties. Our algorithm is able to solve problems with millions of samples and features in seconds, by relying on coordinate descent, working sets and Anderson acceleration. It handl…

Cited by 20SourcePDFScholar
2022

Clipped Stochastic Methods for Variational Inequalities with Heavy-Tailed Noise

NeurIPS 2022accept

Stochastic first-order methods such as Stochastic Extragradient (SEG) or Stochastic Gradient Descent-Ascent (SGDA) for solving smooth minimax problems and, more generally, variational inequality problems (VIP) have been gaining a lot of attention in recent years due to the growing popularity of adve…

2022

Extragradient Method: O(1/K) Last-Iterate Convergence for Monotone Variational Inequalities and Connections With Cocoercivity

AISTATS 2022poster

Extragradient method (EG) (Korpelevich, 1976) is one of the most popular methods for solving saddle point and variational inequalities problems (VIP). Despite its long history and significant attention in the optimization community, there remain important open questions about convergence of EG. In t…

2022

Generalized Natural Gradient Flows in Hidden Convex-Concave Games and GANs

ICLR 2022poster

Game-theoretic formulations in machine learning have recently risen in prominence, whereby entire modeling paradigms are best captured as zero-sum games. Despite their popularity, however, their dynamics are still poorly understood. This lack of theory is often substantiated with painful empirical o…

Cited by 9SourcePDFScholar
2022

Last-Iterate Convergence of Optimistic Gradient Method for Monotone Variational Inequalities

NeurIPS 2022accept

The Past Extragradient (PEG) [Popov, 1980] method, also known as the Optimistic Gradient method, has known a recent gain in interest in the optimization community with the emergence of variational inequality formulations for machine learning. Recently, in the unconstrained case, Golowich et al. [202…

2022

On the Convergence of Stochastic Extragradient for Bilinear Games using Restarted Iteration Averaging

AISTATS 2022poster

We study the stochastic bilinear minimax optimization problem, presenting an analysis of the same-sample Stochastic ExtraGradient (SEG) method with constant step size, and presenting variations of the method that yield favorable convergence. In sharp contrasts with the basic SEG method whose last it…

Cited by 21SourcePDFScholar
2022

Online Adversarial Attacks

ICLR 2022poster

Adversarial attacks expose important vulnerabilities of deep learning models, yet little attention has been paid to settings where data arrives as a stream. In this paper, we formalize the online adversarial attack problem, emphasizing two key elements found in real-world use-cases: attackers must o…

2022

Only tails matter: Average-Case Universality and Robustness in the Convex Regime

ICML 2022spotlight

The recently developed average-case analysis of optimization methods allows a more fine-grained and representative convergence analysis than usual worst-case results. In exchange, this analysis requires a more precise hypothesis over the data generating process, namely assuming knowledge of the expe…

Cited by 11SourcePDFScholar
2022

Stochastic Extragradient: General Analysis and Improved Rates

AISTATS 2022poster

The Stochastic Extragradient (SEG) method is one of the most popular algorithms for solving min-max optimization and variational inequalities problems (VIP) appearing in various machine learning tasks. However, several important questions regarding the convergence properties of SEG are still open, i…

2022

The Curse of Unrolling: Rate of Differentiating Through Optimization

NeurIPS 2022accept

Computing the Jacobian of the solution of an optimization problem is a central problem in machine learning, with applications in hyperparameter optimization, meta-learning, optimization as a layer, and dataset distillation, to name a few. Unrolled differentiation is a popular heuristic that approxim…

Cited by 17SourcePDFScholar
2021

A Limited-Capacity Minimax Theorem for Non-Convex Games or: How I Learned to Stop Worrying about Mixed-Nash and Love Neural Nets

AISTATS 2021poster

Adversarial training, a special case of multi-objective optimization, is an increasingly prevalent machine learning technique: some of its most notable applications include GAN-based generative modeling and self-play techniques in reinforcement learning which have been applied to complex games such…

Cited by 8SourcePDFScholar
2021

A single gradient step finds adversarial examples on random two-layers neural networks

NeurIPS 2021spotlight

Daniely and Schacham recently showed that gradient descent finds adversarial examples on random undercomplete two-layers ReLU neural networks. The term “undercomplete” refers to the fact that their proof only holds when the number of neurons is a vanishing fraction of the ambient dimension. We exten…

Cited by 33SourcePDFScholar
2021

Stochastic Gradient Descent-Ascent and Consensus Optimization for Smooth Games: Convergence Analysis under Expected Co-coercivity

NeurIPS 2021poster

Two of the most prominent algorithms for solving unconstrained smooth games are the classical stochastic gradient descent-ascent (SGDA) and the recently introduced stochastic consensus optimization (SCO) [Mescheder et al., 2017]. SGDA is known to converge to a stationary point for specific classes o…

2020

A Closer Look at the Optimization Landscapes of Generative Adversarial Networks

ICLR 2020poster

Generative adversarial networks have been very successful in generative modeling, however they remain relatively challenging to train compared to standard deep neural networks. In this paper, we propose new visualization techniques for the optimization landscapes of GANs that enable us to study the…

Cited by 83SourcecodeScholar
2020

A Tight and Unified Analysis of Gradient-Based Methods for a Whole Spectrum of Differentiable Games

AISTATS 2020poster

We consider differentiable games where the goal is to find a Nash equilibrium. The machine learning community has recently started using variants of the gradient method (GD). Prime examples are extragradient (EG), the optimistic gradient method (OG) and consensus optimization (CO) which enjoy linear…

Cited by 117SourcePDFScholar
2020

Accelerating Smooth Games by Manipulating Spectral Shapes

AISTATS 2020poster

We use matrix iteration theory to characterize acceleration in smooth games. We define the spectral shape of a family of games as the set containing all eigenvalues of the Jacobians of standard gradient dynamics in the family. Shapes restricted to the real line represent well-understood classes of p…

Cited by 61SourcePDFScholar
2020

Adversarial Example Games

NeurIPS 2020poster

The existence of adversarial examples capable of fooling trained neural network classifiers calls for a much better understanding of possible attacks to guide the development of safeguards against them. This includes attack methods in the challenging {\em non-interactive blackbox} setting, where adv…

2020

Linear Lower Bounds and Conditioning of Differentiable Games

ICML 2020poster

Recent successes of game-theoretic formulations in ML have caused a resurgence of research interest in differentiable games. Overwhelmingly, that research focuses on methods and upper bounds on their speed of convergence. In this work, we approach the question of fundamental iteration complexity by…

Cited by 68SourcePDFScholar
2020

Real World Games Look Like Spinning Tops

NeurIPS 2020poster

This paper investigates the geometrical properties of real world games (e.g. Tic-Tac-Toe, Go, StarCraft II). We hypothesise that their geometrical structure resembles a spinning top, with the upright axis representing transitive strength, and the radial axis representing the non-transitive dimension…

Cited by 130SourcePDFScholar
2019

A Variational Inequality Perspective on Generative Adversarial Networks

ICLR 2019poster

Generative adversarial networks (GANs) form a generative modeling approach known for producing appealing samples, but they are notably difficult to train. One common way to tackle this issue has been to propose new formulations of the GAN objective. Yet, surprisingly few studies have looked at optim…

2019

Implicit Regularization of Discrete Gradient Dynamics in Linear Neural Networks

NeurIPS 2019poster

When optimizing over-parameterized models, such as deep neural networks, a large set of parameters can achieve zero training error. In such cases, the choice of the optimization algorithm and its respective hyper-parameters introduces biases that will lead to convergence to specific minimizers of th…

2019

Negative Momentum for Improved Game Dynamics

AISTATS 2019poster

Games generalize the single-objective optimization paradigm by introducing different objective functions for different players. Differentiable games often proceed by simultaneous or alternating gradient updates. In machine learning, games are gaining new importance through formulations like generati…

2019

Non-normal Recurrent Neural Network (nnRNN): learning long time dependencies while improving expressivity with transient dynamics

NeurIPS 2019poster

A recent strategy to circumvent the exploding and vanishing gradient problem in RNNs, and to allow the stable propagation of signals over long time scales, is to constrain recurrent connectivity matrices to be orthogonal or unitary. This ensures eigenvalues with unit norm and thus stable dynamics an…

2019

Painless Stochastic Gradient: Interpolation, Line-Search, and Convergence Rates

NeurIPS 2019poster

Recent works have shown that stochastic gradient descent (SGD) achieves the fast convergence rates of full-batch gradient descent for over-parameterized models satisfying certain interpolation conditions. However, the step-size used in these works depends on unknown quantities and SGD's practical pe…

2019

Reducing Noise in GAN Training with Variance Reduced Extragradient

NeurIPS 2019poster

We study the effect of the stochastic gradient noise on the training of generative adversarial networks (GANs) and show that it can prevent the convergence of standard game optimization methods, while the batch version converges. We address this issue with a novel stochastic variance-reduced extragr…

Cited by 178SourcePDFScholar
2018

Parametric Adversarial Divergences are Good Task Losses for Generative Modeling

ICLR 2018workshop

Generative modeling of high dimensional data like images is a notoriously difficult and ill-defined problem. In particular, how to evaluate a learned generative model is unclear. In this paper, we argue that *adversarial learning*, pioneered with generative adversarial networks (GANs), provides an i…

Cited by 4SourceScholar