A Homogenization Approach for Gradient-Dominated Stochastic Optimization

Fuente: arXiv
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Autores principales: Tan, Jiyuan, Xue, Chenyu, Zhang, Chuwen, Deng, Qi, Ge, Dongdong, Ye, Yinyu
Formato: Preprint
Publicado: 2023
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author Tan, Jiyuan
Xue, Chenyu
Zhang, Chuwen
Deng, Qi
Ge, Dongdong
Ye, Yinyu
author_facet Tan, Jiyuan
Xue, Chenyu
Zhang, Chuwen
Deng, Qi
Ge, Dongdong
Ye, Yinyu
contents Gradient dominance property is a condition weaker than strong convexity, yet sufficiently ensures global convergence even in non-convex optimization. This property finds wide applications in machine learning, reinforcement learning (RL), and operations management. In this paper, we propose the stochastic homogeneous second-order descent method (SHSODM) for stochastic functions enjoying gradient dominance property based on a recently proposed homogenization approach. Theoretically, we provide its sample complexity analysis, and further present an enhanced result by incorporating variance reduction techniques. Our findings show that SHSODM matches the best-known sample complexity achieved by other second-order methods for gradient-dominated stochastic optimization but without cubic regularization. Empirically, since the homogenization approach only relies on solving extremal eigenvector problem at each iteration instead of Newton-type system, our methods gain the advantage of cheaper computational cost and robustness in ill-conditioned problems. Numerical experiments on several RL tasks demonstrate the better performance of SHSODM compared to other off-the-shelf methods.
format Preprint
id arxiv_https___arxiv_org_abs_2308_10630
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Homogenization Approach for Gradient-Dominated Stochastic Optimization
Tan, Jiyuan
Xue, Chenyu
Zhang, Chuwen
Deng, Qi
Ge, Dongdong
Ye, Yinyu
Optimization and Control
Machine Learning
Gradient dominance property is a condition weaker than strong convexity, yet sufficiently ensures global convergence even in non-convex optimization. This property finds wide applications in machine learning, reinforcement learning (RL), and operations management. In this paper, we propose the stochastic homogeneous second-order descent method (SHSODM) for stochastic functions enjoying gradient dominance property based on a recently proposed homogenization approach. Theoretically, we provide its sample complexity analysis, and further present an enhanced result by incorporating variance reduction techniques. Our findings show that SHSODM matches the best-known sample complexity achieved by other second-order methods for gradient-dominated stochastic optimization but without cubic regularization. Empirically, since the homogenization approach only relies on solving extremal eigenvector problem at each iteration instead of Newton-type system, our methods gain the advantage of cheaper computational cost and robustness in ill-conditioned problems. Numerical experiments on several RL tasks demonstrate the better performance of SHSODM compared to other off-the-shelf methods.
title A Homogenization Approach for Gradient-Dominated Stochastic Optimization
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2308.10630