Deep Relaxation of Controlled Stochastic Gradient Descent via Singular Perturbations

Fuente: arXiv
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Main Authors: Bardi, Martino, Kouhkouh, Hicham
Format: Preprint
Published: 2022
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author Bardi, Martino
Kouhkouh, Hicham
author_facet Bardi, Martino
Kouhkouh, Hicham
contents We consider a singularly perturbed system of stochastic differential equations proposed by Chaudhari et al. (Res. Math. Sci. 2018) to approximate the Entropic Gradient Descent in the optimization of deep neural networks, via homogenisation. We embed it in a much larger class of two-scale stochastic control problems and rely on convergence results for Hamilton-Jacobi-Bellman equations with unbounded data proved recently by ourselves (ESAIM Control Optim. Calc. Var. 2023). We show that the limit of the value functions is itself the value function of an effective control problem with extended controls, and that the trajectories of the perturbed system converge in a suitable sense to the trajectories of the limiting effective control system. These rigorous results improve the understanding of the convergence of the algorithms used by Chaudhari et al., as well as of their possible extensions where some tuning parameters are modelled as dynamic controls.
format Preprint
id arxiv_https___arxiv_org_abs_2209_05564
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Deep Relaxation of Controlled Stochastic Gradient Descent via Singular Perturbations
Bardi, Martino
Kouhkouh, Hicham
Optimization and Control
Probability
93C70, 68T07, 90C26, 93E20
We consider a singularly perturbed system of stochastic differential equations proposed by Chaudhari et al. (Res. Math. Sci. 2018) to approximate the Entropic Gradient Descent in the optimization of deep neural networks, via homogenisation. We embed it in a much larger class of two-scale stochastic control problems and rely on convergence results for Hamilton-Jacobi-Bellman equations with unbounded data proved recently by ourselves (ESAIM Control Optim. Calc. Var. 2023). We show that the limit of the value functions is itself the value function of an effective control problem with extended controls, and that the trajectories of the perturbed system converge in a suitable sense to the trajectories of the limiting effective control system. These rigorous results improve the understanding of the convergence of the algorithms used by Chaudhari et al., as well as of their possible extensions where some tuning parameters are modelled as dynamic controls.
title Deep Relaxation of Controlled Stochastic Gradient Descent via Singular Perturbations
topic Optimization and Control
Probability
93C70, 68T07, 90C26, 93E20
url https://arxiv.org/abs/2209.05564