A primal-dual splitting algorithm with convex combination and larger step sizes for composite monotone inclusion problems

Fuente: arXiv
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Main Authors: Chang, Xiaokai, Yang, Junfeng, Bai, Jianchao, Cao, Jianxiong
Format: Preprint
Published: 2025
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author Chang, Xiaokai
Yang, Junfeng
Bai, Jianchao
Cao, Jianxiong
author_facet Chang, Xiaokai
Yang, Junfeng
Bai, Jianchao
Cao, Jianxiong
contents The primal-dual splitting algorithm (PDSA) by Chambolle and Pock is efficient for solving structured convex optimization problems. It adopts an extrapolation step and achieves convergence under certain step size condition. Chang and Yang recently proposed a modified PDSA for bilinear saddle point problems, integrating a convex combination step to enable convergence with extended step sizes. In this paper, we focus on composite monotone inclusion problems (CMIPs), a generalization of convex optimization problems. While Vu extended PDSA to CMIPs, whether the modified PDSA can be directly adapted to CMIPs remains an open question. This paper introduces a new PDSA for CMIPs, featuring the inclusion of both an extrapolation step and a convex combination step. The proposed algorithm is reformulated as a fixed-point iteration by leveraging an extended firmly nonexpansive operator. Under a significantly relaxed step size condition, both its convergence and sublinear convergence rate results are rigorously established. For structured convex optimization problem, we establish its sublinear convergence rate results measured by function value gap and constraint violations. Moreover, we show through a concrete example that our condition on the involved parameters cannot be relaxed. Numerical experiments on image denoising, inpainting, matrix games, and LASSO problems are conducted to compare the proposed algorithm with state-of-the-art counterparts, demonstrating the efficiency of the proposed algorithm.
format Preprint
id arxiv_https___arxiv_org_abs_2510_00437
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A primal-dual splitting algorithm with convex combination and larger step sizes for composite monotone inclusion problems
Chang, Xiaokai
Yang, Junfeng
Bai, Jianchao
Cao, Jianxiong
Optimization and Control
The primal-dual splitting algorithm (PDSA) by Chambolle and Pock is efficient for solving structured convex optimization problems. It adopts an extrapolation step and achieves convergence under certain step size condition. Chang and Yang recently proposed a modified PDSA for bilinear saddle point problems, integrating a convex combination step to enable convergence with extended step sizes. In this paper, we focus on composite monotone inclusion problems (CMIPs), a generalization of convex optimization problems. While Vu extended PDSA to CMIPs, whether the modified PDSA can be directly adapted to CMIPs remains an open question. This paper introduces a new PDSA for CMIPs, featuring the inclusion of both an extrapolation step and a convex combination step. The proposed algorithm is reformulated as a fixed-point iteration by leveraging an extended firmly nonexpansive operator. Under a significantly relaxed step size condition, both its convergence and sublinear convergence rate results are rigorously established. For structured convex optimization problem, we establish its sublinear convergence rate results measured by function value gap and constraint violations. Moreover, we show through a concrete example that our condition on the involved parameters cannot be relaxed. Numerical experiments on image denoising, inpainting, matrix games, and LASSO problems are conducted to compare the proposed algorithm with state-of-the-art counterparts, demonstrating the efficiency of the proposed algorithm.
title A primal-dual splitting algorithm with convex combination and larger step sizes for composite monotone inclusion problems
topic Optimization and Control
url https://arxiv.org/abs/2510.00437