Welcome to Defeng Sun's Home Page

Defeng SUN (孫德鋒)

Chair Professor

Department of Applied Mathematics

The Hong Kong Polytechnic University

Hong Kong

 

Fellow:

SIAM, CSIAM, ORSC

Education
Research Interests
Teaching
Recruitments
Professional Activities

Recognitions
Codes

Some Recent Talks
Some Old Talks
Publications

 

SUN Defeng

Department of Applied Mathematics
The Hong Kong Polytechnic University 
Hung Hom, Kowloon, Hong Kong

 

Office: TU 728, Yip Kit Chuen Building

Phone: +852 2766 6935

Fax: +852 2362 9045

Email: defeng.sun@polyu.edu.hk

Web: https://www.polyu.edu.hk/ama/profile/dfsun

Education

BSc (1989), MSc (1992) both from Department of Mathematics,  Nanjing University, Nanjing

PhD (1995) from Institute of Applied Mathematics, Chinese Academy of Sciences, Beijing [Supervisor: Professor Jiye Han (韩继业)]

Recent Research Interests

Teaching

Recruitments

Professional Activities

·       President, The Hong Kong Mathematical Society (May 2020—May 2024).

·       Organizing Committee Co-Chair and Local Organizing Committee Co-Chair, “SIAM Conference on Optimization (OP20), 

The Hong Kong Polytechnic University, Hong Kong,  May 26-29, 2020. Rescheduled and Relocated https://www.siam.org/conferences/cm/conference/op21.

·       Program Committee Member, “The Sixth International Conference on Continuous Optimization (ICCOPT 2019)”, Berlin, August 5-8, 2019.

·       Program Committee Member, “The Fifth International Conference on Continuous Optimization (ICCOPT 2016)”, Tokyo, August 6-11, 2016.

·       Associate Editor, Mathematical Programming (Series A, August 2007 --; Series B, January 2014--December 2017). 

·       Associate Editor, SIAM Journal on Optimization (January 2012--). 

·       Associate Editor, Journal of the Operations Research Society of China (2012)

·       Associate Editor, Journal of Computational Mathematics (2017--).

·       Associate Editor, Science China Mathematics (January 2018 --).

·       Associate Editor, Journal of Optimization Theory and Applications (2021 --).

·       Advisory Committee Member, Asia-Pacific Journal of Operational Research (January 2014--); editor-in-chief (October 2010 –December 2013).

·       Society Membership: INFORMS, SIAM, MOS, AMS, CSIAM, HKMS and etc.

Recognitions

Codes in Matlab and others

Codes for nearest (covariance) correlation matrix problems

Codes under the Matrix Optimization (MatOpt) Project

 

[Xudong Li, Defeng Sun, and Kim Chuan Toh,  QSDPNAL: A two-phase augmented Lagrangian method for convex quadratic semidefinite programming”, Mathematical Programming Computation, 10 (2018) 703--743.]

[Xudong Li, Defeng Sun, and Kim Chuan Toh, “A block symmetric Gauss-Seidel decomposition theorem for convex composite quadratic programming and its applications”, Mathematical Programming 175 (2019) 395--418. arXiv:1703.06629]

 

[Defeng Sun, Kim Chuan Toh, Y.C. Yuan, Xinyuan Zhao, SDPNAL+: A Matlab software for semidefinite programming with bound constraints (version 1.0), to appear in Optimization Methods and Software (2019).]

[Liuqin Yang, Defeng Sun, and Kim Chuan Toh, SDPNAL+: a majorized semismooth Newton-CG augmented Lagrangian method for semidefinite programming with nonnegative constraints, Mathematical Programming Computation, 7 (2015), pp. 331-366.]

[Defeng Sun, Kim Chuan Toh, and Liuqin Yang, “A convergent 3-block semi-proximal alternating direction method of multipliers for conic programming with 4-type constraints”, SIAM Journal on Optimization Vol. 25, No. 2 (2015) 882–915. Detailed computational results for over 400 problems tested in the paper. You may also find a supplementary note here on more detailed comparisons between the performance of our proposed algorithm and various variants of ADMMs.]

[Xinyuan Zhao, D.F. Sun, and Kim Chuan Toh, A Newton-CG augmented Lagrangian method for semidefinite programming, SIAM Journal on Optimization, 20 (2010), pp. 1737--1765.]

 

Codes under the Statistical Optimization (StaOpt) Project

[Peipei Tang, Chengjing Wang, Defeng Sun, and Kim Chuan Toh,  “A sparse semismooth Newton based proximal majorization-minimization algorithm for nonconvex square-root-loss regression problems”, Journal of Machine Learning Research 21(226):1--38, 2020.]

 

 

 

Codes for rank constrained problems

Codes for other problems

Some recent talks

Some old talks

Selected Publications

Click here for my google scholar page.

Click here for my ORCID page.

Technical Reports

 Click here for the arXived

 

 

2025 –-

 

·       Liang Chen, Ruoning Chen, Defeng Sun, and Liping Zhang, “Equivalent characterizations of the Aubin property for nonlinear semidefinite programming”, Mathematical Programming (2025), in print. arXiv:2408.08232 (August 2024).  A Road Map on the Proof.

·       Guojun Zhang, Zhexuan Gu, Yancheng Yuan, and Defeng Sun,HOT: An Efficient Halpern Accelerating Algorithm for Optimal Transport Problems”, IEEE Transactions on Pattern Analysis and Machine Intelligence (2025), in print. arXiv:2408.00598  (August  2024).

·       Yancheng Yuan, Meixia Lin, Defeng Sun, and Kim-Chuan Toh, “Adaptive sieving: A dimension reduction technique for sparse optimization problems”,  Mathematical Programming Computation (2025), in print. arXiv:2306.17369 (2023; Revised September 2024).

·       Zhenzhi Qin, Zhenyu Ming, Defeng Sun, and Liping Zhang, “Low-rank quaternion tensor completion for color video inpainting via a novel factorization strategy”, Mathematics of Computation (2025), in print. arXiv:2403.16480.

·       Defeng Sun, Yancheng Yuan, Guojun Zhang, and Xinyuan Zhao, “Accelerating preconditioned ADMM via degenerate proximal point mappings”, SIAM Journal on Optimization 35 (2025), in print.  arXiv:2403.18618 (March 2024; Revised December 2024).

·       Liang Chen, Ruoning Chen, Defeng Sun, and Junyuan Zhu, “Aubin property and strong regularity are equivalent for nonlinear second-order cone programming”, SIAM Journal on Optimization 35:2 (2025) 712--738. See the Flowchart of the Proof.

·       Ling Liang, D.F. Sun, and Kim-Chuan Toh, “A squared smoothing Newton method for semidefinite programming”, Mathematics of Operations Research (2025), in print. arXiv:2303.05825.

·       Shenglong Hu, D.F. Sun, and Kim-Chuan Toh, “Quantifying low rank approximations of third order symmetric tensors”, Mathematical Programming (2025), in print. arXiv:2307.10855 (2023).

·       Jiawang Nie, Defeng Sun, Xindong Tang, and Min Zhang, “Solving polynomial variational inequality problems via Lagrange multiplier expressions and Moment-SOS relaxations”, Computation al Optimization and Applications 90 (2025) 361--394.

·       Bo  Yang, Xinyuan Zhao, Xudong Li, and D.F. Sun,An accelerated proximal alternating direction method of multipliers for optimal decentralized control of uncertain systems”, Journal of Optimization Theory and Applications 204.1 (2025):9.

·       Shulan Zhu, Chenglong Bao, Defeng Sun, and Yancheng Yuan, “A tight convergence analysis of inexact stochastic proximal point algorithm for stochastic composite optimization problems”, ICLR 2025.

 

2024

 

·       Xixi Jia, Fangchen Feng, Deyu Meng, and Defeng Sun,Globally Q-linear Gauss-Newton method for overparameterized non-convex matrix sensing”, Advances in Neural Information Processing Systems 37  (NeurIPS 2024), 20428-20459.

·       Meixia Lin, D.F. Sun, Kim-Chuan Toh, and C.J. Wang, “Estimation of sparse Gaussian graphical models with hidden clustering structure”, Journal of Machine Learning Research 25(256): 1--36, 2024.

·       Qian Li, D.F. Sun, and Y.C. Yuan, “An efficient sieving based secant method for sparse optimization problems with least-squares constraints”, SIAM Journal on Optimization 34:2 (2024)  2038–-2066.

·       Meixia Lin, Yancheng Yuan, Defeng Sun,  and  Kim-Chuan Toh,  A highly efficient algorithm for solving exclusive Lasso problems”,  Optimization Methods and Software 39: 3 (2024) 489--518.

·       Yangjing Zhang, Kim-Chuan Toh, and D.F. Sun,Learning graph Laplacian with MCP”, Optimization Methods and Software 39:3 (2024) 569--600.

 

2023

 

·       D. Zhang, Shaohua Pan, S. Bi, and D.F. Sun,Zero-norm regularized problems: equivalent surrogates, proximal MM method and statistical error bound”, Computational Optimization and Applications 86:2 (2023)  627–-667.

·       S. Wang, Y. Xu, Z. Wang, T.-H. Chang, T. QS Quek, and D.F. Sun,Beyond ADMM: A unified client-variance-reduced adaptive federated learning framework”. In Proceedings of the AAAI Conference on Artificial Intelligence, vol. 37, no. 8, pp. 10175-10183. 2023.

·       Can Wu, Ying Cui, D.H. Li, and D.F. Sun,Convex and nonconvex risk-based linear regression at scale”, INFORMS Journal on Computing 35 (4): 797-816, 2023.

·       Qian Li, Binyan Jiang, and D.F. Sun,MARS: a second-order reduction algorithm for high-dimensional sparse precision matrices estimation”, Journal of Machine Learning Research 24 (134):1−44, 2023.

·       L.P. Zhang, D.F. Sun, and Z.T. Luan, “Solvability of monotone tensor complementarity problems”, SCIENCE CHINA Mathematics 66 (2023)  647–-664.

 

2022

 

·       Y.C. Yuan, T.-H. Chang, D.F. Sun, and Kim-Chuan Toh, “A dimension reduction technique for structured sparse optimization problems with application to convex clustering”, SIAM Journal on Optimization 32 (2022) 2294--2318.

·       Ling Liang, X.D. Li, D.F. Sun, and Kim-Chuan Toh, “QPPAL: A two-phase proximal augmented Lagrangian method for high dimensional convex quadratic programming problems”, ACM Transactions on Mathematical Software 48 (2022), no. 3, Art. 33, 27 pp.

·       Xueying Zhao, Minru Bai, Defeng Sun, and Libin Zheng   Robust tensor completion: Equivalent surrogates, error bounds and algorithms”, SIAM Journal on Imaging Sciences 15 (2022) 625–-669.

·       Ying Cui, Ling Liang, Defeng Sun, and Kim Chuan Toh, “On degenerate doubly nonnegative projection problems”, Mathematics of Operations Research 47 (2022)  2219—2239.

·       Meixia Lin,  Defeng Sun, and  Kim Chuan Toh, “An augmented Lagrangian method with constraint generations for shape-constrained convex regression problems”, Mathematical Programming Computation 14 (2022)  223–-270.

 

2021

 

·       Ling Liang, Defeng Sun, and Kim Chuan Toh, “An inexact augmented Lagrangian method for second-order cone programming with applications”, SIAM Journal on Optimization 31:3 (2021) 1748--1773. 

·       Xin Yee Lam, Defeng Sun, and Kim Chuan Toh,  “A semi-proximal augmented Lagrangian based decomposition method for primal block angular convex composite quadratic conic programming problems”, INFORMS Journal on Optimization 3:3 (2021) 254--277.  arXiv:1812.04941

·       Ran Yan, Shuaian Wang, Jiannong Cao, and Defeng Sun, “ Shipping Domain Knowledge Informed  Prediction and Optimziation in Port State Control”, Transportation Research Part B 149 (2021) 52--78.  

·       Lei Yang, Jia Li, Defeng Sun, and Kim Chuan Toh,  A fast globally linearly convergent algorithm for the computation of Wasserstein barycenters”, Journal of Machine Learning Research 22(21):1−37, 2021. 

·       Defeng Sun,  Kim Chuan Toh, and Yancheng Yuan,  “Convex clustering: Model, theoretical guarantee and efficient algorithm”, Journal of Machine Learning Research 22(9):1−32, 2021. 

·       Ning Zhang, Yangjing Zhang,  Defeng Sun, and Kim Chuan Toh, An efficient linearly convergent regularized proximal point algorithm for fused multiple graphical Lasso problems”, SIAM Journal on Mathematics of Data Science 3:2 (2021) 524--543. 

·       Liang Chen, Xudong Li, Defeng Sun, and Kim Chuan Toh, On the equivalence of inexact proximal ALM and ADMM for a class of convex composite programming”, Mathematical Programming 185 (2021) 111—161 [Correction to the Proof of Lemma 3.3].

 

2020

 

·       Peipei Tang, Chengjing Wang, Defeng Sun, and Kim Chuan Toh,  “A sparse semismooth Newton based proximal majorization-minimization algorithm for nonconvex square-root-loss regression problems”, Journal of Machine Learning Research 21(226):1--38, 2020. [See the software package square_root_PMM]

·       Shujun Bi, Shaohua Pan, and Defeng Sun,  “A multi-stage convex relaxation approach to   noisy structured low-rank matrix recovery”, Mathematical Programming Computation 12 (2020) 569--602.

·       Xudong Li, Defeng Sun, and Kim Chuan Toh, An asymptotically superlinearly convergent semismooth Newton augmented Lagrangian method for linear programming, SIAM Journal on Optimization 30 (2020) 2410--2440. 

·       Yangjing Zhang, Ning Zhang, Defeng Sun, and Kim Chuan Toh, “A proximal point dual Newton algorithm for solving group graphical Lasso problems”, SIAM Journal on Optimization 30 (2020) 2197--2220. 

·       Chao Ding, Defeng Sun, Jie Sun, and Kim Chuan Toh, “Spectral operators of matrices: semismoothness and characterizations of the generalized Jacobian”, SIAM Journal on Optimization 30 (2020) 630--659. [Revised from the second part of https://arxiv.org/abs/1401.2269, January 2014.]

·       Xudong Li, Defeng Sun, and Kim Chuan Toh, On the efficient computation of a generalized Jacobian of the projector over the Birkhoff polytope, Mathematical Programming 179 (2020) 419—446.

·       Yangjing Zhang, Ning Zhang, Defeng Sun, and Kim Chuan Toh, An efficient Hessian based algorithm for solving large-scale sparse group Lasso problems”,   Mathematical Programming 179 (2020) 223--263 [DOI:10.1007/s10107-018-1329-6] https://arxiv.org/pdf/1712.05910.pdf

·       Defeng Sun, Kim Chuan Toh, Yancheng Yuan, Xin-Yuan Zhao, “SDPNAL+: A Matlab software for semidefinite programming with bound constraints (version 1.0)”, Optimization Methods and Software 35 (2020) 87--115.

2019

·       Ziyan Luo, Defeng Sun, Kim Chuan Toh,  Naihua Xiu, “Solving the OSCAR and SLOPE models using a semismooth Newton-based augmented Lagrangian method”,  Journal of Machine Learning Research 20(106):1--25, 2019.

·       Liang Chen, Defeng Sun, Kim Chuan Toh,  Ning Zhang,  A unified algorithmic framework of symmetric Gauss-Seidel decomposition based proximal ADMMs for convex composite programming”, Journal of Computational Mathematics 37 (2019) 739--757.

·       Shenglong Hu, Defeng Sun, Kim Chuan Toh, “Best nonnegative rank-one approximations of tensors”, SIAM Journal on Matrix Analysis and Applications 40 (2019) 1527--1554. 

·       Ying Cui, Defeng Sun, Kim Chuan Toh, “Computing the best approximation over the intersection of a polyhedral set and the doubly nonnegative cone”, SIAM Journal on Optimization 29 (2019) 2785--2813. 

·       Meixia Lin, Yong-Jin Liu, Defeng Sun, Kim Chuan Toh,  “Efficient sparse semismooth Newton methods for the clustered lasso problem”, SIAM Journal on Optimization 29 (2019) 2026--2052. 

·       Liang Chen, Defeng Sun, Kim Chuan Toh,   Some problems on the Gauss-Seidel iteration method in degenerate cases”, Journal on Numerical Methods and Computer Applications, 40 (2019) 98--110 (in Chinese)

·       Ying Cui, Defeng Sun, and Kim Chuan Toh,  On the R-superlinear convergence of  the KKT residuals generated by the augmented Lagrangian method for  convex  composite conic programming”, Mathematical Programming 178 (2019) 381—415.

·       Xudong Li, Defeng Sun, and Kim Chuan Toh, “A block symmetric Gauss-Seidel decomposition theorem for convex composite quadratic programming and its applications”, Mathematical Programming 175 (2019) 395--418. arXiv:1703.06629

 

Theses of Students:

2018

·       Yancheng Yuan, Defeng Sun and Kim Chuan Toh,  An efficient semismooth Newton based algorithm for convex clustering”, Proceedings of the 35-th International Conference on Machine Learning (ICML), Stockholm, Sweden, PMLR 80, 2018.

·       Xin Yee Lam, J.S. Marron, Defeng Sun, and Kim Chuan Toh,  Fast algorithms for large scale generalized distance weighted discrimination”, Journal of Computational and Graphical Statistics 27 (2018) 368--379.  arXiv:1604.05473.

·       Xudong Li, Defeng Sun, and Kim Chuan Toh,  QSDPNAL: A two-phase augmented Lagrangian method for convex quadratic semidefinite programming”, Mathematical Programming Computation, 10 (2018) 703--743. https://arxiv.org/pdf/1512.08872.pdf

·       Xudong Li, Defeng Sun, and Kim Chuan Toh,  On efficiently solving the subproblems of a level-set method for fused lasso problems”, SIAM Journal on Optimization 28 (2018) 1842--1862. https://arxiv.org/abs/1512.08872

·       Deren Han, Defeng Sun, and Liwei Zhang, “Linear rate convergence of the alternating direction method of multipliers for convex composite programming’’, Mathematics of Operations Research 43 (2018) 622--637. [Revised from the first part of arXiv:1508.02134, August 2015.]

·       Chao Ding, Defeng Sun, Jie Sun, and Kim Chuan Toh, Spectral operators of matrices”, Mathematical Programming 168 (2018) 509--531. [Revised from the first part of https://arxiv.org/abs/1401.2269, January 2014.]

·       Ying Cui and Defeng Sun, “A complete characterization on the robust isolated calmness of the nuclear norm regularized convex optimization problems”,   Journal of Computational Mathematics 36(3) (2018) 441--458.

·       Xudong Li, Defeng Sun, and Kim Chuan Toh, “A highly efficient semismooth Newton augmented Lagrangian method for solving Lasso problems’’, SIAM Journal on Optimization 28 (2018) 433--458.

 [ This paper brought Xudong Li the Best Paper Prize for Young Researchers in Continuous Optimization announced in the ICCOPT 2019 held in Berlin, August 3-8, 2019. This is the only prize given in the flagship international conference on continuous optimization held every three years].

 

Theses of Students:

2017

·       Chao Ding, Defeng Sun, and Liwei Zhang, “Characterization of the robust isolated calmness for a class of conic programming problems”, arXiv:1601.07418. SIAM Journal on Optimization 27 (2017) 67--90.

·       Liang Chen, Defeng Sun, and Kim Chuan Toh,  A note on the convergence of ADMM for linearly constrained convex optimization problems”, arXiv:1507.02051. Computational Optimization and Applications 66 (2017) 327--343.  [In this note a comprehensive proof is supplied to clarify many ambiguities/incorrect proofs in the literature].

·       Liang Chen, Defeng Sun, and Kim Chuan Toh, An efficient inexact symmetric Gauss-Seidel based majorized ADMM for high-dimensional convex composite conic programming”, arXiv:1506.00741. Mathematical Programming 161 (2017) 237--270.

 

Theses of Students:

 

2016

 

             Theses of Students:

2015

 

 

           Theses of Students:

2014

 

Theses of Students:

2013

 

Theses of Students:

        2012

 

Theses of Students:  

2011

2010

 

Theses of Students:

2009

 

Theses of Students:

2008

2007

2006

2005

 

Theses of Students:

2004

 

Theses of Students:

2003

2002

2001

2000

1999

1998

1997

1996

1995 

 

 

1994

1993

D.F. Sun,Projected extragradient method for finding saddle points of general convex programming”, Qufu Shifan Daxue Xuebao Ziran Kexue Ban 19:4 (1993) 10--17.

Return to: Department of Applied Mathematics,  Faculty of Computer and Mathematical Sciences, The Hong Kong Polytechnic University


Last Modified: April 8, 2025
Defeng Sun, Department of Applied Mathematics, Faculty of Computer and Mathematical Sciences, The Hong Kong Polytechnic University