Mirror Descent-Ascent for mean-field min-max problems

Fuente: arXiv
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Auteurs principaux: Lascu, Razvan-Andrei, Majka, Mateusz B., Szpruch, Łukasz
Format: Preprint
Publié: 2024
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author Lascu, Razvan-Andrei
Majka, Mateusz B.
Szpruch, Łukasz
author_facet Lascu, Razvan-Andrei
Majka, Mateusz B.
Szpruch, Łukasz
contents We study two variants of the mirror descent-ascent (MDA) algorithm for solving min-max problems on the space of measures: simultaneous and alternating. We work under assumptions of convexity-concavity and relative smoothness of the payoff function with respect to a suitable Bregman divergence, defined on the space of measures via flat derivatives. We establish non-asymptotic convergence rates to mixed Nash equilibria, measured in the Nikaidô-Isoda error, proving an $\mathcal{O}(N^{-1/2})$ rate for simultaneous MDA and an improved $\mathcal{O}(N^{-2/3})$ rate for alternating MDA. The main technical contribution is an infinite-dimensional dual space analysis that relates Bregman divergences on measures to dual Bregman divergences on spaces of bounded continuous functions, allowing us to control asymmetric commutator terms created by alternating updates. The results substantially generalize prior analyses restricted to bilinear objectives and also apply to nonlinear convex-concave problems on measure spaces, thereby providing a unified theoretical foundation for MDA in mean-field min-max optimization.
format Preprint
id arxiv_https___arxiv_org_abs_2402_08106
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mirror Descent-Ascent for mean-field min-max problems
Lascu, Razvan-Andrei
Majka, Mateusz B.
Szpruch, Łukasz
Optimization and Control
Machine Learning
Probability
We study two variants of the mirror descent-ascent (MDA) algorithm for solving min-max problems on the space of measures: simultaneous and alternating. We work under assumptions of convexity-concavity and relative smoothness of the payoff function with respect to a suitable Bregman divergence, defined on the space of measures via flat derivatives. We establish non-asymptotic convergence rates to mixed Nash equilibria, measured in the Nikaidô-Isoda error, proving an $\mathcal{O}(N^{-1/2})$ rate for simultaneous MDA and an improved $\mathcal{O}(N^{-2/3})$ rate for alternating MDA. The main technical contribution is an infinite-dimensional dual space analysis that relates Bregman divergences on measures to dual Bregman divergences on spaces of bounded continuous functions, allowing us to control asymmetric commutator terms created by alternating updates. The results substantially generalize prior analyses restricted to bilinear objectives and also apply to nonlinear convex-concave problems on measure spaces, thereby providing a unified theoretical foundation for MDA in mean-field min-max optimization.
title Mirror Descent-Ascent for mean-field min-max problems
topic Optimization and Control
Machine Learning
Probability
url https://arxiv.org/abs/2402.08106