On Penalty-based Bilevel Gradient Descent Method

Fuente: arXiv
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Autori principali: Shen, Han, Xiao, Quan, Chen, Tianyi
Natura: Preprint
Pubblicazione: 2023
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author Shen, Han
Xiao, Quan
Chen, Tianyi
author_facet Shen, Han
Xiao, Quan
Chen, Tianyi
contents Bilevel optimization enjoys a wide range of applications in emerging machine learning and signal processing problems such as hyper-parameter optimization, image reconstruction, meta-learning, adversarial training, and reinforcement learning. However, bilevel optimization problems are traditionally known to be difficult to solve. Recent progress on bilevel algorithms mainly focuses on bilevel optimization problems through the lens of the implicit-gradient method, where the lower-level objective is either strongly convex or unconstrained. In this work, we tackle a challenging class of bilevel problems through the lens of the penalty method. We show that under certain conditions, the penalty reformulation recovers the (local) solutions of the original bilevel problem. Further, we propose the penalty-based bilevel gradient descent (PBGD) algorithm and establish its finite-time convergence for the constrained bilevel problem with lower-level constraints yet without lower-level strong convexity. Experiments on synthetic and real datasets showcase the efficiency of the proposed PBGD algorithm.
format Preprint
id arxiv_https___arxiv_org_abs_2302_05185
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On Penalty-based Bilevel Gradient Descent Method
Shen, Han
Xiao, Quan
Chen, Tianyi
Machine Learning
Optimization and Control
Bilevel optimization enjoys a wide range of applications in emerging machine learning and signal processing problems such as hyper-parameter optimization, image reconstruction, meta-learning, adversarial training, and reinforcement learning. However, bilevel optimization problems are traditionally known to be difficult to solve. Recent progress on bilevel algorithms mainly focuses on bilevel optimization problems through the lens of the implicit-gradient method, where the lower-level objective is either strongly convex or unconstrained. In this work, we tackle a challenging class of bilevel problems through the lens of the penalty method. We show that under certain conditions, the penalty reformulation recovers the (local) solutions of the original bilevel problem. Further, we propose the penalty-based bilevel gradient descent (PBGD) algorithm and establish its finite-time convergence for the constrained bilevel problem with lower-level constraints yet without lower-level strong convexity. Experiments on synthetic and real datasets showcase the efficiency of the proposed PBGD algorithm.
title On Penalty-based Bilevel Gradient Descent Method
topic Machine Learning
Optimization and Control
url https://arxiv.org/abs/2302.05185