Fast Frank--Wolfe Algorithms with Adaptive Bregman Step-Size for Weakly Convex Functions

Fuente: arXiv
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Autori principali: Takahashi, Shota, Pokutta, Sebastian, Takeda, Akiko
Natura: Preprint
Pubblicazione: 2025
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author Takahashi, Shota
Pokutta, Sebastian
Takeda, Akiko
author_facet Takahashi, Shota
Pokutta, Sebastian
Takeda, Akiko
contents We propose Frank--Wolfe (FW) algorithms with an adaptive Bregman step-size strategy for smooth adaptable (also called: relatively smooth) (weakly-) convex functions. This means that the gradient of the objective function is not necessarily Lipschitz continuous, and we only require the smooth adaptable property. Compared with existing FW algorithms, our assumptions are less restrictive. We establish convergence guarantees in various settings, including convergence rates ranging from sublinear to linear, depending on the assumptions for convex and nonconvex objective functions. Assuming that the objective function is weakly convex and satisfies the local quadratic growth condition, we provide both local sublinear and local linear convergence with respect to the primal gap. We also propose a variant of the away-step FW algorithm using Bregman distances over polytopes. We establish faster global convergence (up to a linear rate) for convex optimization under the Hölder error bound condition and local linear convergence for nonconvex optimization under the local quadratic growth condition. Numerical experiments demonstrate that our proposed FW algorithms outperform existing methods.
format Preprint
id arxiv_https___arxiv_org_abs_2504_04330
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fast Frank--Wolfe Algorithms with Adaptive Bregman Step-Size for Weakly Convex Functions
Takahashi, Shota
Pokutta, Sebastian
Takeda, Akiko
Optimization and Control
65K05, 90C06, 90C25, 90C26, 90C30
We propose Frank--Wolfe (FW) algorithms with an adaptive Bregman step-size strategy for smooth adaptable (also called: relatively smooth) (weakly-) convex functions. This means that the gradient of the objective function is not necessarily Lipschitz continuous, and we only require the smooth adaptable property. Compared with existing FW algorithms, our assumptions are less restrictive. We establish convergence guarantees in various settings, including convergence rates ranging from sublinear to linear, depending on the assumptions for convex and nonconvex objective functions. Assuming that the objective function is weakly convex and satisfies the local quadratic growth condition, we provide both local sublinear and local linear convergence with respect to the primal gap. We also propose a variant of the away-step FW algorithm using Bregman distances over polytopes. We establish faster global convergence (up to a linear rate) for convex optimization under the Hölder error bound condition and local linear convergence for nonconvex optimization under the local quadratic growth condition. Numerical experiments demonstrate that our proposed FW algorithms outperform existing methods.
title Fast Frank--Wolfe Algorithms with Adaptive Bregman Step-Size for Weakly Convex Functions
topic Optimization and Control
65K05, 90C06, 90C25, 90C26, 90C30
url https://arxiv.org/abs/2504.04330