Towards Weaker Variance Assumptions for Stochastic Optimization

Fuente: arXiv
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Auteurs principaux: Alacaoglu, Ahmet, Malitsky, Yura, Wright, Stephen J.
Format: Preprint
Publié: 2025
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author Alacaoglu, Ahmet
Malitsky, Yura
Wright, Stephen J.
author_facet Alacaoglu, Ahmet
Malitsky, Yura
Wright, Stephen J.
contents We revisit a classical assumption for analyzing stochastic gradient algorithms where the squared norm of the stochastic subgradient (or the variance for smooth problems) is allowed to grow as fast as the squared norm of the optimization variable. We contextualize this assumption in view of its inception in the 1960s, its seemingly independent appearance in the recent literature, its relationship to weakest-known variance assumptions for analyzing stochastic gradient algorithms, and its relevance in deterministic problems for non-Lipschitz nonsmooth convex optimization. We build on and extend a connection recently made between this assumption and the Halpern iteration. For convex nonsmooth, and potentially stochastic, optimization, we analyze horizon-free, anytime algorithms with last-iterate rates. For problems beyond simple constrained optimization, such as convex problems with functional constraints or regularized convex-concave min-max problems, we obtain rates for optimality measures that do not require boundedness of the feasible set.
format Preprint
id arxiv_https___arxiv_org_abs_2504_09951
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Towards Weaker Variance Assumptions for Stochastic Optimization
Alacaoglu, Ahmet
Malitsky, Yura
Wright, Stephen J.
Optimization and Control
Machine Learning
We revisit a classical assumption for analyzing stochastic gradient algorithms where the squared norm of the stochastic subgradient (or the variance for smooth problems) is allowed to grow as fast as the squared norm of the optimization variable. We contextualize this assumption in view of its inception in the 1960s, its seemingly independent appearance in the recent literature, its relationship to weakest-known variance assumptions for analyzing stochastic gradient algorithms, and its relevance in deterministic problems for non-Lipschitz nonsmooth convex optimization. We build on and extend a connection recently made between this assumption and the Halpern iteration. For convex nonsmooth, and potentially stochastic, optimization, we analyze horizon-free, anytime algorithms with last-iterate rates. For problems beyond simple constrained optimization, such as convex problems with functional constraints or regularized convex-concave min-max problems, we obtain rates for optimality measures that do not require boundedness of the feasible set.
title Towards Weaker Variance Assumptions for Stochastic Optimization
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2504.09951