Improving Convergence Guarantees of Random Subspace Second-order Algorithm for Nonconvex Optimization

Fuente: arXiv
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Main Authors: Higuchi, Rei, Poirion, Pierre-Louis, Takeda, Akiko
Format: Preprint
Published: 2024
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author Higuchi, Rei
Poirion, Pierre-Louis
Takeda, Akiko
author_facet Higuchi, Rei
Poirion, Pierre-Louis
Takeda, Akiko
contents In recent years, random subspace methods have been actively studied for large-dimensional nonconvex problems. Recent subspace methods have improved theoretical guarantees such as iteration complexity and local convergence rate while reducing computational costs by deriving descent directions in randomly selected low-dimensional subspaces. This paper proposes the Random Subspace Homogenized Trust Region (RSHTR) method with the best theoretical guarantees among random subspace algorithms for nonconvex optimization. RSHTR achieves an $\varepsilon$-approximate first-order stationary point in $O(\varepsilon^{-3/2})$ iterations, converging locally at a linear rate. Furthermore, under rank-deficient conditions, RSHTR satisfies $\varepsilon$-approximate second-order necessary conditions in $O(\varepsilon^{-3/2})$ iterations and exhibits a local quadratic convergence. Experiments on real-world datasets verify the benefits of RSHTR.
format Preprint
id arxiv_https___arxiv_org_abs_2406_14337
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Improving Convergence Guarantees of Random Subspace Second-order Algorithm for Nonconvex Optimization
Higuchi, Rei
Poirion, Pierre-Louis
Takeda, Akiko
Optimization and Control
90C06, 90C26, 90C30
In recent years, random subspace methods have been actively studied for large-dimensional nonconvex problems. Recent subspace methods have improved theoretical guarantees such as iteration complexity and local convergence rate while reducing computational costs by deriving descent directions in randomly selected low-dimensional subspaces. This paper proposes the Random Subspace Homogenized Trust Region (RSHTR) method with the best theoretical guarantees among random subspace algorithms for nonconvex optimization. RSHTR achieves an $\varepsilon$-approximate first-order stationary point in $O(\varepsilon^{-3/2})$ iterations, converging locally at a linear rate. Furthermore, under rank-deficient conditions, RSHTR satisfies $\varepsilon$-approximate second-order necessary conditions in $O(\varepsilon^{-3/2})$ iterations and exhibits a local quadratic convergence. Experiments on real-world datasets verify the benefits of RSHTR.
title Improving Convergence Guarantees of Random Subspace Second-order Algorithm for Nonconvex Optimization
topic Optimization and Control
90C06, 90C26, 90C30
url https://arxiv.org/abs/2406.14337