Leveraging Continuous Time to Understand Momentum When Training Diagonal Linear Networks

Fuente: arXiv
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Autores principales: Papazov, Hristo, Pesme, Scott, Flammarion, Nicolas
Formato: Preprint
Publicado: 2024
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author Papazov, Hristo
Pesme, Scott
Flammarion, Nicolas
author_facet Papazov, Hristo
Pesme, Scott
Flammarion, Nicolas
contents In this work, we investigate the effect of momentum on the optimisation trajectory of gradient descent. We leverage a continuous-time approach in the analysis of momentum gradient descent with step size $γ$ and momentum parameter $β$ that allows us to identify an intrinsic quantity $λ= \frac{ γ}{ (1 - β)^2 }$ which uniquely defines the optimisation path and provides a simple acceleration rule. When training a $2$-layer diagonal linear network in an overparametrised regression setting, we characterise the recovered solution through an implicit regularisation problem. We then prove that small values of $λ$ help to recover sparse solutions. Finally, we give similar but weaker results for stochastic momentum gradient descent. We provide numerical experiments which support our claims.
format Preprint
id arxiv_https___arxiv_org_abs_2403_05293
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Leveraging Continuous Time to Understand Momentum When Training Diagonal Linear Networks
Papazov, Hristo
Pesme, Scott
Flammarion, Nicolas
Machine Learning
Optimization and Control
In this work, we investigate the effect of momentum on the optimisation trajectory of gradient descent. We leverage a continuous-time approach in the analysis of momentum gradient descent with step size $γ$ and momentum parameter $β$ that allows us to identify an intrinsic quantity $λ= \frac{ γ}{ (1 - β)^2 }$ which uniquely defines the optimisation path and provides a simple acceleration rule. When training a $2$-layer diagonal linear network in an overparametrised regression setting, we characterise the recovered solution through an implicit regularisation problem. We then prove that small values of $λ$ help to recover sparse solutions. Finally, we give similar but weaker results for stochastic momentum gradient descent. We provide numerical experiments which support our claims.
title Leveraging Continuous Time to Understand Momentum When Training Diagonal Linear Networks
topic Machine Learning
Optimization and Control
url https://arxiv.org/abs/2403.05293