Designed and built with care, filled with creative elements

Top

ENS-Data Science colloquium – Rebecca Willett : How do simple rotations affect the implicit bias of Adam?

Amphi Jean Jaurès 29 rue d'Ulm, PARIS, France

Adaptive gradient methods such as Adam and Adagrad are widely used in = machine learning, yet their effect on the generalization of learned = models =E2=80=93 relative to methods like gradient descent =E2=80=93 = remains poorly understood. Prior work on binary classification suggests = that Adam exhibits a =E2=80=9Crichness bias,=E2=80=9D which can help it = learn nonlinear decision boundaries closer to the Bayes-optimal decision = boundary relative to gradient descent. However, the coordinate-wise = preconditioning scheme employed by Adam renders the overall method = sensitive to orthogonal transformations of feature […]

Learning Monge Maps with Constrained Drifting Models

Salle W

The estimation of optimal transport maps (a.k.a. Monge maps) is a central problem in optimal transport literature. Recent observations reveal that the flow map of the Wasserstein gradient flow of the relative entropy closely approximates—though does not exactly equal—the Monge map between a given source distribution and a Gaussian target. In this work, we demonstrate how the evolution equation governing this flow map can be corrected to form a constrained gradient flow that provably converges to the true Monge map.When the maps are parametrized as gradients of convex models (e.g. […]

Hélène Mathis – Modélisation d’écoulements diphasiques compressibles

Salle W - ENS PSL 45 rue d'Ulm, Paris, France

Première partie : La modélisation et la simulation d’écoulements diphasiques constituent un sujet de recherche important, notamment pour leurs applications en sûreté nucléaire.Dans certains scenarii d’accidents interviennent des écoulements très hétérogènes, constitués d’eau liquide et de bulles d’air et/ou de vapeur.Afin de modéliser de tels écoulements, on privilégie des modèles moyennés, donnant une description macroscopique des écoulements, la description à l’échelle des interfaces eau-gaz étant hors portée.Cependant connaître les propriétés de l’interface, en particulier l’évolution de l’aire interfaciale et de la tension de surface, demeure important.Dans cette première partie, nous […]

Constant Bourdrez et Hanna Benarroch

Salle W

Constant Bourdrez : "Learning To Sample From Diffusion Models Via Inverse Reinforcement Learning" Hanna Benarroch : "Certified Per-instance Unlearning using Individual Sensitivity Bounds"

Convexity in Whitney Problems

Salle W (ENS)

Suppose E is a compact subset of R^n, and we are given a function f, mapping E to the real numbers. How can we tell if the function lies on a smooth convex function? Can we construct an almost optimal, smooth, convex interpolant of the function? These are examples of Whitney-type extension and trace problems; while theoretical, they are driven by practical questions of interpolation of data, where convexity is a natural constraint. I will begin with an answer to these questions by presenting work of mine proving there is a […]