Séminaire Images Optimisation et Probabilités
(Proba-stats) Sample and Map from a Single Convex Potential: Generation using Conjugate Moment Measures
Nina Vesseron
( ENSAE )Salle de conférences
le 10 avril 2025 à 11:15
A common approach to generative modeling is to split model-fitting into two blocks: define first how to sample noise (e.g. Gaussian) and choose next what to do with it (e.g. using a single map or flows). We explore in this work an alternative route that ties sampling and mapping. We find inspiration in moment measures, a result that states that for any measure supported on a compact convex set of , there exists a unique convex potential such that . While this does seem to tie effectively sampling (from log-concave distribution ) and action (pushing particles through ), we observe on simple examples (e.g., Gaussians or 1D distributions) that this choice is ill-suited for practical tasks. We study an alternative factorization, where is factorized as , where is the convex conjugate of . We call this approach conjugate moment measures, and show far more intuitive results on these examples. Because is the Monge map between the log-concave distribution and , we rely on optimal transport solvers to propose an algorithm to recover from samples of , and parameterize as an input convex neural network.