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Bibliographic Details
Main Authors: Ahn, Kwangjun, Magakyan, Gagik, Cutkosky, Ashok
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.07061
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author Ahn, Kwangjun
Magakyan, Gagik
Cutkosky, Ashok
author_facet Ahn, Kwangjun
Magakyan, Gagik
Cutkosky, Ashok
contents This work investigates the effectiveness of schedule-free methods, developed by A. Defazio et al. (NeurIPS 2024), in nonconvex optimization settings, inspired by their remarkable empirical success in training neural networks. Specifically, we show that schedule-free SGD achieves optimal iteration complexity for nonsmooth, nonconvex optimization problems. Our proof begins with the development of a general framework for online-to-nonconvex conversion, which converts a given online learning algorithm into an optimization algorithm for nonconvex losses. Our general framework not only recovers existing conversions but also leads to two novel conversion schemes. Notably, one of these new conversions corresponds directly to schedule-free SGD, allowing us to establish its optimality. Additionally, our analysis provides valuable insights into the parameter choices for schedule-free SGD, addressing a theoretical gap that the convex theory cannot explain.
format Preprint
id arxiv_https___arxiv_org_abs_2411_07061
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle General framework for online-to-nonconvex conversion: Schedule-free SGD is also effective for nonconvex optimization
Ahn, Kwangjun
Magakyan, Gagik
Cutkosky, Ashok
Machine Learning
Optimization and Control
This work investigates the effectiveness of schedule-free methods, developed by A. Defazio et al. (NeurIPS 2024), in nonconvex optimization settings, inspired by their remarkable empirical success in training neural networks. Specifically, we show that schedule-free SGD achieves optimal iteration complexity for nonsmooth, nonconvex optimization problems. Our proof begins with the development of a general framework for online-to-nonconvex conversion, which converts a given online learning algorithm into an optimization algorithm for nonconvex losses. Our general framework not only recovers existing conversions but also leads to two novel conversion schemes. Notably, one of these new conversions corresponds directly to schedule-free SGD, allowing us to establish its optimality. Additionally, our analysis provides valuable insights into the parameter choices for schedule-free SGD, addressing a theoretical gap that the convex theory cannot explain.
title General framework for online-to-nonconvex conversion: Schedule-free SGD is also effective for nonconvex optimization
topic Machine Learning
Optimization and Control
url https://arxiv.org/abs/2411.07061