Mean-Field Langevin Dynamics for Signed Measures via a Bilevel Approach

Fuente: arXiv
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Main Authors: Wang, Guillaume, Mousavi-Hosseini, Alireza, Chizat, Lénaïc
Format: Preprint
Published: 2024
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author Wang, Guillaume
Mousavi-Hosseini, Alireza
Chizat, Lénaïc
author_facet Wang, Guillaume
Mousavi-Hosseini, Alireza
Chizat, Lénaïc
contents Mean-field Langevin dynamics (MLFD) is a class of interacting particle methods that tackle convex optimization over probability measures on a manifold, which are scalable, versatile, and enjoy computational guarantees. However, some important problems -- such as risk minimization for infinite width two-layer neural networks, or sparse deconvolution -- are originally defined over the set of signed, rather than probability, measures. In this paper, we investigate how to extend the MFLD framework to convex optimization problems over signed measures. Among two known reductions from signed to probability measures -- the lifting and the bilevel approaches -- we show that the bilevel reduction leads to stronger guarantees and faster rates (at the price of a higher per-iteration complexity). In particular, we investigate the convergence rate of MFLD applied to the bilevel reduction in the low-noise regime and obtain two results. First, this dynamics is amenable to an annealing schedule, adapted from Suzuki et al. (2023), that results in improved convergence rates to a fixed multiplicative accuracy. Second, we investigate the problem of learning a single neuron with the bilevel approach and obtain local exponential convergence rates that depend polynomially on the dimension and noise level (to compare with the exponential dependence that would result from prior analyses).
format Preprint
id arxiv_https___arxiv_org_abs_2406_17054
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mean-Field Langevin Dynamics for Signed Measures via a Bilevel Approach
Wang, Guillaume
Mousavi-Hosseini, Alireza
Chizat, Lénaïc
Optimization and Control
Machine Learning
Mean-field Langevin dynamics (MLFD) is a class of interacting particle methods that tackle convex optimization over probability measures on a manifold, which are scalable, versatile, and enjoy computational guarantees. However, some important problems -- such as risk minimization for infinite width two-layer neural networks, or sparse deconvolution -- are originally defined over the set of signed, rather than probability, measures. In this paper, we investigate how to extend the MFLD framework to convex optimization problems over signed measures. Among two known reductions from signed to probability measures -- the lifting and the bilevel approaches -- we show that the bilevel reduction leads to stronger guarantees and faster rates (at the price of a higher per-iteration complexity). In particular, we investigate the convergence rate of MFLD applied to the bilevel reduction in the low-noise regime and obtain two results. First, this dynamics is amenable to an annealing schedule, adapted from Suzuki et al. (2023), that results in improved convergence rates to a fixed multiplicative accuracy. Second, we investigate the problem of learning a single neuron with the bilevel approach and obtain local exponential convergence rates that depend polynomially on the dimension and noise level (to compare with the exponential dependence that would result from prior analyses).
title Mean-Field Langevin Dynamics for Signed Measures via a Bilevel Approach
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2406.17054