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Main Authors: Li, Shuyao, Wright, Stephen J.
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2310.18841
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author Li, Shuyao
Wright, Stephen J.
author_facet Li, Shuyao
Wright, Stephen J.
contents We consider minimization of a smooth nonconvex function with inexact oracle access to gradient and Hessian (without assuming access to the function value) to achieve approximate second-order optimality. A novel feature of our method is that if an approximate direction of negative curvature is chosen as the step, we choose its sense to be positive or negative with equal probability. We allow gradients to be inexact in a relative sense and relax the coupling between inexactness thresholds for the first- and second-order optimality conditions. Our convergence analysis includes both an expectation bound based on martingale analysis and a high-probability bound based on concentration inequalities. We apply our algorithm to empirical risk minimization problems and obtain improved gradient sample complexity over existing works.
format Preprint
id arxiv_https___arxiv_org_abs_2310_18841
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A randomized algorithm for nonconvex minimization with inexact evaluations and complexity guarantees
Li, Shuyao
Wright, Stephen J.
Optimization and Control
Machine Learning
We consider minimization of a smooth nonconvex function with inexact oracle access to gradient and Hessian (without assuming access to the function value) to achieve approximate second-order optimality. A novel feature of our method is that if an approximate direction of negative curvature is chosen as the step, we choose its sense to be positive or negative with equal probability. We allow gradients to be inexact in a relative sense and relax the coupling between inexactness thresholds for the first- and second-order optimality conditions. Our convergence analysis includes both an expectation bound based on martingale analysis and a high-probability bound based on concentration inequalities. We apply our algorithm to empirical risk minimization problems and obtain improved gradient sample complexity over existing works.
title A randomized algorithm for nonconvex minimization with inexact evaluations and complexity guarantees
topic Optimization and Control
Machine Learning
url https://arxiv.org/abs/2310.18841