Characterizing Dynamical Stability of Stochastic Gradient Descent in Overparameterized Learning

Fuente: arXiv
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Main Authors: Chemnitz, Dennis, Engel, Maximilian
Format: Preprint
Published: 2024
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author Chemnitz, Dennis
Engel, Maximilian
author_facet Chemnitz, Dennis
Engel, Maximilian
contents For overparameterized optimization tasks, such as those found in modern machine learning, global minima are generally not unique. In order to understand generalization in these settings, it is vital to study to which minimum an optimization algorithm converges. The possibility of having minima that are unstable under the dynamics imposed by the optimization algorithm limits the potential minima that the algorithm can find. In this paper, we characterize the global minima that are dynamically stable/unstable for both deterministic and stochastic gradient descent (SGD). In particular, we introduce a characteristic Lyapunov exponent that depends on the local dynamics around a global minimum and rigorously prove that the sign of this Lyapunov exponent determines whether SGD can accumulate at the respective global minimum.
format Preprint
id arxiv_https___arxiv_org_abs_2407_20209
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Characterizing Dynamical Stability of Stochastic Gradient Descent in Overparameterized Learning
Chemnitz, Dennis
Engel, Maximilian
Machine Learning
Dynamical Systems
Probability
For overparameterized optimization tasks, such as those found in modern machine learning, global minima are generally not unique. In order to understand generalization in these settings, it is vital to study to which minimum an optimization algorithm converges. The possibility of having minima that are unstable under the dynamics imposed by the optimization algorithm limits the potential minima that the algorithm can find. In this paper, we characterize the global minima that are dynamically stable/unstable for both deterministic and stochastic gradient descent (SGD). In particular, we introduce a characteristic Lyapunov exponent that depends on the local dynamics around a global minimum and rigorously prove that the sign of this Lyapunov exponent determines whether SGD can accumulate at the respective global minimum.
title Characterizing Dynamical Stability of Stochastic Gradient Descent in Overparameterized Learning
topic Machine Learning
Dynamical Systems
Probability
url https://arxiv.org/abs/2407.20209