Minibatch and Local SGD: Algorithmic Stability and Linear Speedup in Generalization

Fuente: arXiv
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Main Authors: Lei, Yunwen, Sun, Tao, Liu, Mingrui
Format: Preprint
Published: 2023
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author Lei, Yunwen
Sun, Tao
Liu, Mingrui
author_facet Lei, Yunwen
Sun, Tao
Liu, Mingrui
contents The increasing scale of data propels the popularity of leveraging parallelism to speed up the optimization. Minibatch stochastic gradient descent (minibatch SGD) and local SGD are two popular methods for parallel optimization. The existing theoretical studies show a linear speedup of these methods with respect to the number of machines, which, however, is measured by optimization errors in a multi-pass setting. As a comparison, the stability and generalization of these methods are much less studied. In this paper, we study the stability and generalization analysis of minibatch and local SGD to understand their learnability by introducing an expectation-variance decomposition. We incorporate training errors into the stability analysis, which shows how small training errors help generalization for overparameterized models. We show minibatch and local SGD achieve a linear speedup to attain the optimal risk bounds.
format Preprint
id arxiv_https___arxiv_org_abs_2310_01139
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Minibatch and Local SGD: Algorithmic Stability and Linear Speedup in Generalization
Lei, Yunwen
Sun, Tao
Liu, Mingrui
Machine Learning
Artificial Intelligence
The increasing scale of data propels the popularity of leveraging parallelism to speed up the optimization. Minibatch stochastic gradient descent (minibatch SGD) and local SGD are two popular methods for parallel optimization. The existing theoretical studies show a linear speedup of these methods with respect to the number of machines, which, however, is measured by optimization errors in a multi-pass setting. As a comparison, the stability and generalization of these methods are much less studied. In this paper, we study the stability and generalization analysis of minibatch and local SGD to understand their learnability by introducing an expectation-variance decomposition. We incorporate training errors into the stability analysis, which shows how small training errors help generalization for overparameterized models. We show minibatch and local SGD achieve a linear speedup to attain the optimal risk bounds.
title Minibatch and Local SGD: Algorithmic Stability and Linear Speedup in Generalization
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2310.01139