Journal of the Operations Research Society of China ›› 2019, Vol. 7 ›› Issue (2): 365-383.doi: 10.1007/s40305-019-00247-y

Special Issue: Continuous Optimization

Previous Articles     Next Articles

An LQP-Based Symmetric Alternating Direction Method of Multipliers with Larger Step Sizes

Zhong-Ming Wu1, Min Li2   

  1. 1 School of Economics and Management, Southeast University, Nanjing 210096, China;
    2 School of Management and Engineering, Nanjing University, Nanjing 210093, China
  • Received:2018-08-08 Revised:2018-12-16 Online:2019-06-30 Published:2019-06-30
  • Contact: Zhong-Ming Wu, Min Li E-mail:wuzm@seu.edu.cn;limin@nju.edu.cn
  • Supported by:
    This research was supported by National Natural Science Foundation of China Grant 11771078, Natural Science Foundation of Jiangsu Province Grant BK20181258, Project of 333 of Jiangsu Province Grant BRA2018351 and Postgraduate Research & Practice Innovation Program of Jiangsu Province Grant KYCX18_0200.

Abstract: Symmetric alternating direction method of multipliers (ADMM) is an efficient method for solving a class of separable convex optimization problems. Thismethod updates the Lagrange multiplier twice with appropriate step sizes at each iteration. However, such step sizes were conservatively shrunk to guarantee the convergence in recent studies. In this paper, we are devoted to seeking larger step sizes whenever possible. The logarithmic-quadratic proximal (LQP) terms are applied to regularize the symmetric ADMM subproblems, allowing the constrained subproblems to then be converted to easier unconstrained ones. Theoretically, we prove the global convergence of such LQP-based symmetric ADMM by specifying a larger step size domain. Moreover, the numerical results on a traffic equilibrium problem are reported to demonstrate the advantage of the method with larger step sizes.

Key words: Convex optimization, Symmetric alternating direction method of multipliers, Logarithmic-quadratic proximal regularization, Larger step sizes, Global convergence

CLC Number: