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Shangzhi Zeng

10 accepted papers

2025

A Single-Loop Gradient Algorithm for Pessimistic Bilevel Optimization via Smooth Approximation

NeurIPS 2025poster

Bilevel optimization has garnered significant attention in the machine learning community recently, particularly regarding the development of efficient numerical methods. While substantial progress has been made in developing efficient algorithms for optimistic bilevel optimization, the study of me…

Cited by 0SourceScholar
2025

Overcoming Lower-Level Constraints in Bilevel Optimization: A Novel Approach with Regularized Gap Functions

ICLR 2025poster

Constrained bilevel optimization tackles nested structures present in constrained learning tasks like constrained meta-learning, adversarial learning, and distributed bilevel optimization. However, existing bilevel optimization methods mostly are typically restricted to specific constraint settings…

2024

Constrained Bi-Level Optimization: Proximal Lagrangian Value Function Approach and Hessian-free Algorithm

ICLR 2024spotlight

This paper presents a new approach and algorithm for solving a class of constrained Bi-Level Optimization (BLO) problems in which the lower-level problem involves constraints coupling both upper-level and lower-level variables. Such problems have recently gained significant attention due to their br…

Cited by 17SourcePDFScholar
2024

Moreau Envelope for Nonconvex Bi-Level Optimization: A Single-Loop and Hessian-Free Solution Strategy

ICML 2024poster

This work focuses on addressing two major challenges in the context of large-scale nonconvex Bi-Level Optimization (BLO) problems, which are increasingly applied in machine learning due to their ability to model nested structures. These challenges involve ensuring computational efficiency and provid…

Cited by 9SourcePDFScholar
2023

Averaged Method of Multipliers for Bi-Level Optimization without Lower-Level Strong Convexity

ICML 2023poster

Gradient methods have become mainstream techniques for Bi-Level Optimization (BLO) in learning fields. The validity of existing works heavily rely on either a restrictive Lower- Level Strong Convexity (LLSC) condition or on solving a series of approximation subproblems with high accuracy or both. In…

2022

Optimization-Derived Learning with Essential Convergence Analysis of Training and Hyper-training

ICML 2022spotlight

Recently, Optimization-Derived Learning (ODL) has attracted attention from learning and vision areas, which designs learning models from the perspective of optimization. However, previous ODL approaches regard the training and hyper-training procedures as two separated stages, meaning that the hyper…

Cited by 6SourcePDFScholar
2022

Value Function based Difference-of-Convex Algorithm for Bilevel Hyperparameter Selection Problems

ICML 2022spotlight

Existing gradient-based optimization methods for hyperparameter tuning can only guarantee theoretical convergence to stationary solutions when the bilevel program satisfies the condition that for fixed upper-level variables, the lower-level is strongly convex (LLSC) and smooth (LLS). This condition…

2021

A Value-Function-based Interior-point Method for Non-convex Bi-level Optimization

ICML 2021spotlight

Bi-level optimization model is able to capture a wide range of complex learning tasks with practical interest. Due to the witnessed efficiency in solving bi-level programs, gradient-based methods have gained popularity in the machine learning community. In this work, we propose a new gradient-based…

Cited by 89SourcePDFScholar
2021

Towards Gradient-based Bilevel Optimization with Non-convex Followers and Beyond

NeurIPS 2021spotlight

In recent years, Bi-Level Optimization (BLO) techniques have received extensive attentions from both learning and vision communities. A variety of BLO models in complex and practical tasks are of non-convex follower structure in nature (a.k.a., without Lower-Level Convexity, LLC for short). However,…

2020

A Generic First-Order Algorithmic Framework for Bi-Level Programming Beyond Lower-Level Singleton

ICML 2020poster

In recent years, a variety of gradient-based bi-level optimization methods have been developed for learning tasks. However, theoretical guarantees of these existing approaches often heavily rely on the simplification that for each fixed upper-level variable, the lower-level solution must be a single…

Cited by 146SourcePDFScholar