Proximal Dogleg Opportunistic Majorization for Nonconvex and Nonsmooth Optimization

Fuente: arXiv
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Autores principales: Zhou, Yiming, Dai, Wei
Formato: Preprint
Publicado: 2024
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author Zhou, Yiming
Dai, Wei
author_facet Zhou, Yiming
Dai, Wei
contents We consider minimizing a function consisting of a quadratic term and a proximable term which is possibly nonconvex and nonsmooth. This problem is also known as scaled proximal operator. Despite its simple form, existing methods suffer from slow convergence or high implementation complexity or both. To overcome these limitations, we develop a fast and user-friendly second-order proximal algorithm. Key innovation involves building and solving a series of opportunistically majorized problems along a hybrid Newton direction. The approach directly uses the precise Hessian of the quadratic term, and calculates the inverse only once, eliminating the iterative numerical approximation of the Hessian, a common practice in quasi-Newton methods. The algorithm's convergence to a critical point is established, and local convergence rate is derived based on the Kurdyka-Lojasiewicz property of the objective function. Numerical comparisons are conducted on well-known optimization problems. The results demonstrate that the proposed algorithm not only achieves a faster convergence but also tends to converge to a better local optimum compare to benchmark algorithms.
format Preprint
id arxiv_https___arxiv_org_abs_2402_19176
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Proximal Dogleg Opportunistic Majorization for Nonconvex and Nonsmooth Optimization
Zhou, Yiming
Dai, Wei
Optimization and Control
Signal Processing
We consider minimizing a function consisting of a quadratic term and a proximable term which is possibly nonconvex and nonsmooth. This problem is also known as scaled proximal operator. Despite its simple form, existing methods suffer from slow convergence or high implementation complexity or both. To overcome these limitations, we develop a fast and user-friendly second-order proximal algorithm. Key innovation involves building and solving a series of opportunistically majorized problems along a hybrid Newton direction. The approach directly uses the precise Hessian of the quadratic term, and calculates the inverse only once, eliminating the iterative numerical approximation of the Hessian, a common practice in quasi-Newton methods. The algorithm's convergence to a critical point is established, and local convergence rate is derived based on the Kurdyka-Lojasiewicz property of the objective function. Numerical comparisons are conducted on well-known optimization problems. The results demonstrate that the proposed algorithm not only achieves a faster convergence but also tends to converge to a better local optimum compare to benchmark algorithms.
title Proximal Dogleg Opportunistic Majorization for Nonconvex and Nonsmooth Optimization
topic Optimization and Control
Signal Processing
url https://arxiv.org/abs/2402.19176