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Introduction to Nonlinear Combinatorial Optimization. Ding-Zhu Du University of Texas at Dallas. What is Nonlinear Combinatorial Optimization?. Ding-Zhu Du University of Texas at Dallas. Nonlinear & Discrete.
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Introduction to Nonlinear Combinatorial Optimization Ding-Zhu Du University of Texas at Dallas
What is Nonlinear Combinatorial Optimization? Ding-Zhu Du University of Texas at Dallas
Nonlinear & Discrete • A combinatorial optimization problem with nonlinear objective function and/or constraints. • A nonlinear optimization problem with discrete (combinatorial) structure.
1st Example Topological Control in Wireless Networks
Given a wireless network, find a power assignment to every nodes to minimize the total energy consumption such that the connectivity of the network is preserved. Symmetric Topological Control
Symmetric xxx Asymmetric xxx
Min Spanning Tree Minimum Spanning Tree Problem is polynomial-time solvable.
Symmetric Topological Control Symmetric Topological Control Problem is NP-hard!
Asymmetric Topological Control Asymmetric Topological Control Problem is NP-hard!
2nd Example Job Scheduling in Cloud Computing
Scheduling with energy consideration 2 • In cloud computing, jobs’ processing time is determined nonlinearly by energy assignment. • Suppose total energy is given. How to assign energy to jobs in order to minimize the makespan.
Alternating Direction Method • Fixed energy assignment, find optimal or good approximate solution for classic scheduling problem. • Fixed job scheduling, find a good energy assignment.
Work of Bingsheng He • Convergent with two group of variables • Not convergent with 3 or more.
3rd Example Influence Maximization in Social Networks
Subareas • 0-1 program: set function optimization • Integer program: lattice point optimization (including discrete DC programming) • Mixed integer program
5 Discrete Convex Analysis Kazuo Murota
Discrete Newton Method 6 • Inverse optimization problem • Survey by Zhao Zhang
Relaxation 7/8 • LP-relaxation (Linear Program) • SD-relaxation (Semi-definite Program) • Convex-relaxation (Convex Program); primal-dual method with convex program (STOC,SODA) • Continuous-relation (Discrete DC Program); a prima-dual method with discrete DC program is possible.
What is discrete DC program? 8 • DC: Difference of Convex • Convex-extensible
What is discrete DC program? • Discrete DC function • Lin-vex extension
Convex closure &extension Convex closure Convex extension
Toland-Singer duality Why a primal-dual method exists?
First try on discrete DC program Dachuan Xu
9 Why NCO may develop well now? Final Remark
What more important? • In development of applied math, what is more important? • Deeper mathematics? • Solid application?
Previously • One proposed some NCO problems from theoretical point of view. • But, NCO didn’t get strong support from applications.
Today • NCO gets a lot of applications. • Its theoretical foundation starts to grow.