Solving the Static Design Routing and Wavelength Assignment Problem

Size: px
Start display at page:

Download "Solving the Static Design Routing and Wavelength Assignment Problem"

Transcription

1 Solving the Static Design Routing and Wavelength Assignment Problem Helmut Simonis Cork Constraint Computation Centre Computer Science Department University College Cork Ireland CSCLP 009, Barcelona Helmut Simonis Static Design RWA

2 Outline Problem Problem Helmut Simonis Static Design RWA

3 Main Points Problem Compare static design and demand acceptance versions of RWA See impact of objective function Compare finite domain, MIP and SAT solutions Helmut Simonis Static Design RWA

4 Outline Problem Problem Helmut Simonis Static Design RWA

5 Problem Definition Routing and Wavelength Assignment (Static Design) In an optical network, traffic demands between nodes are assigned to a route through the network and a specific wavelength. The route (called lightpath) must be a simple path from source to destination. Demands which are routed over the same link must be allocated to different wavelengths, but wavelengths may be reused for demands which do not meet. The objective is to find a combined routing and wavelength assignment which minimizes the number of wavelengths used for a given set of demands. Helmut Simonis Static Design RWA

6 RWA Problem Variants Static design Accept all demands Minimize frequencies required Design problem Demand acceptance Number of frequencies fixed Maximize number of demands accepted Operational problem Helmut Simonis Static Design RWA 6

7 Example Network (NSF, nodes) Helmut Simonis Static Design RWA 7

8 Lightpath from node to node ( ) Helmut Simonis Static Design RWA 8

9 Conflict with demand : Use different frequencies Helmut Simonis Static Design RWA 9

10 Conflict with demand : Use different path Helmut Simonis Static Design RWA 0

11 Solution Approaches Greedy heuristic Optimization algorithm for complete problem into two problems Find routing Assign wavelengths Helmut Simonis Static Design RWA

12 Solution Approaches Greedy heuristic Optimization algorithm for complete problem into two problems Find routing Assign wavelengths Helmut Simonis Static Design RWA

13 Outline Problem Problem Helmut Simonis Static Design RWA

14 What is the Objective? Basic model Minimize number of frequencies used on any link Cost of equipment (?) Extended model Minimize overall number of frequencies Cost of renting fibres (?) Helmut Simonis Static Design RWA

15 Notation Problem Network (N,E) directed graph with nodes N and edges E Demands D from source s(d) to sink t(d) Out(n) all links leaving n, In(n) all links entering n Available frequencies Λ 0/ integer variables xde λ, demand d is routed over edge e using frequency λ 0/ integer variables yd λ, demand d is using frequency λ Helmut Simonis Static Design RWA

16 Basic Model s.t. Problem min max e E d D,λ Λ x λ de yd λ {0, }, x de λ {0, } d D : yd λ = λ Λ e E, λ Λ : xde λ d D d D, λ Λ : xde λ = 0, xde λ = y d λ d D, λ Λ : e In(s(d)) e Out(s(d)) xde λ = 0, xde λ = y d λ e Out(t(d)) e In(t(d)) d D, λ Λ, n N \ {s(d), t(d)} : xde λ = xde λ e In(n) e Out(n) Helmut Simonis Static Design RWA 6

17 Extended Model, Additional Variables Minimize the total number of variables used 0/ integer variables z λ, frequency λ is used by at least one demand Helmut Simonis Static Design RWA 7

18 Extended Model min z λ λ Λ s.t. z λ {0, }, yd λ {0, }, x de λ {0, } d D : yd λ = λ Λ d D, e E, λ Λ : xde λ zλ e E, λ Λ : xde λ d D d D, λ Λ : xde λ = 0, xde λ = y d λ d D, λ Λ : e In(s(d)) e Out(s(d)) xde λ = 0, xde λ = y d λ e Out(t(d)) e In(t(d)) d D, λ Λ, n N \ {s(d), t(d)} : xde λ = xde λ e In(n) e Out(n) Helmut Simonis Static Design RWA 8

19 s Problem Scalability Network size Number of demands Symmetries in model Helmut Simonis Static Design RWA 9

20 Improvement: Source Aggregation Combine all demands starting in common source Removes some, but not all symmetries 0/ integer variables x λ se, a demand starting in s is routed over edge e using frequency λ Integer objective z max Integer P sd, number of demands between s and d Set D s, all destinations for demands starting in s Helmut Simonis Static Design RWA 0

21 Source Aggregation, Basic Model min z max s.t. z max {0,... Λ }, xse λ {0, } e E, λ Λ : xse λ s N s N, λ Λ : xse λ = 0 e In(s) s N, d D s, λ Λ : xse λ xse λ e In(d) e Out(d) s N, d D s : xse λ = xse λ + P sd λ Λ e In(d) λ Λ e Out(d) s N, n s, n / D s, λ Λ : xse λ = xse λ e In(n) e Out(n) e E : xse λ zmax s N λ Λ Helmut Simonis Static Design RWA

22 Observations Problem Basic model scales reasonably well Extended model very poor LP relaxation extremely weak LP bound Neither works well enough for larger problem sizes Aggregated model does not directly provide solution Helmut Simonis Static Design RWA

23 Outline Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Helmut Simonis Static Design RWA

24 Solution Approach Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model MIP - MIP Based MIP - SAT/FD based decomposition MIP Resource Model Optimization Problem MIP Resource Model Optimization Problem Extract Accepted Demands Extract Accepted Demands MIP Graph Coloring Optimization Problem SAT/FD Graph Coloring Decision Problem Solution Solved? Yes Solution No Increase Nr Wavelengths Helmut Simonis Static Design RWA

25 Idea Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Simplify source aggregation model by ignoring frequencies Integer variables z se, how many demands sourced in s are routed over e Integer objective z max, corresponds to basic problem Constraints independent of number of frequencies, number of demands Helmut Simonis Static Design RWA

26 Phase MIP Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model s.t. min z max z max {0,... Λ }, z se {0,...T s } s N : z se = 0 s N, d D s : s N, n s, n / D s : e E : e In(s) e In(d) e In(n) z se = z se = z se + P sd e Out(d) e Out(n) z se z max s N z se Helmut Simonis Static Design RWA 6

27 Demand Extraction Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Find path for each demand Non-deterministic, backtrack free search Remove loops at same time Procedural Result: Predicate p(d, e) whether demand d is routed over edge e Helmut Simonis Static Design RWA 7

28 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Resource Requirements (Static Design) Color Off Capacity 0 unused Helmut Simonis Static Design RWA 8

29 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Compare: Requirements (Demand Acceptance) 6 0 Color Off Capacity 0 unused Helmut Simonis Static Design RWA 9

30 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA 0

31 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA

32 Source Model Solution Source Node S Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link Helmut Simonis Static Design RWA

33 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S 7 Helmut Simonis Static Design RWA

34 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link 8 S Helmut Simonis Static Design RWA

35 Source Model Solution Source Node 6 S Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model 6 Color Type Source Sink Unreached Chosen Link Helmut Simonis Static Design RWA

36 Source Model Solution Source Node 7 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA 6

37 Source Model Solution Source Node 8 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link 8 S Helmut Simonis Static Design RWA 7

38 Source Model Solution Source Node 9 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA 8

39 Source Model Solution Source Node 0 6 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model S 8 Color Type Source Sink Unreached Chosen Link Helmut Simonis Static Design RWA 9

40 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA 0

41 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA

42 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA

43 Source Model Solution Source Node Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model 8 Color Type Source Sink Unreached Chosen Link S Helmut Simonis Static Design RWA

44 Comparison Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Shortest Path Routed Demands Helmut Simonis Static Design RWA

45 Phase MIP Idea Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Assign each demand to a frequency Basic model: Minimize the largest number of frequencies used on any link Extended model: Minimize total number of frequencies 0/ integer variables xd λ, whether demand d uses frequency λ Extended model only: 0/ integer variables z λ Clash constraints: Only one demand can use each frequency on a link Helmut Simonis Static Design RWA

46 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Phase MIP Model (Basic Problem) min z max s.t. xd λ {0, },z max {0,,..., Λ } d D : xd λ = e E λ Λ : e E : λ Λ {d D p(d,e)} λ Λ {d D p(d,e)} x λ d x λ d z max Helmut Simonis Static Design RWA 6

47 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Phase MIP Model (Extended Problem) s.t. min z max xd λ {0, }, zλ {0, },z max {0,,..., Λ } d D : xd λ = e E λ Λ : e E : λ Λ {d D p(d,e)} λ Λ {d D p(d,e)} x λ d x λ d z max d D λ Λ : xd λ zλ z λ z max Helmut λ ΛSimonis Static Design RWA 7

48 Finite Domain Model, Idea Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Graph coloring problem Finite domain variables y d, demand d is assigned to frequency y d Two demands routed over same edge must use different frequencies Binary disequality constraints Aggregated to alldifferent constraints Finite domain variables n e, edge e uses n e frequencies nvalue constraint counts number of different values used Helmut Simonis Static Design RWA 8

49 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Phase Finite Domain Constraints (Basic Model) s.t. min max e E n e y d {0,..., Λ }, n e {0,..., Λ } e E : nvalue(n e, {y d p(d, e)}) e E : alldifferent({y d p(d, e)}) Helmut Simonis Static Design RWA 9

50 Simplification Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model nvalue and alldifferent constraints are over same variable sets Values of alldifferent constraint must be different nvalue constraints can be removed n e variables are not required Not an optimization problem! Helmut Simonis Static Design RWA 0

51 Simplified Basic Model Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model y d {0,..., Λ } e E : alldifferent({y d p(d, e)}) Helmut Simonis Static Design RWA

52 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Phase Finite Domain Constraints (Extended Model) s.t. min max d D y d y d {0,..., Λ } e E : alldifferent({y d p(d, e)}) Helmut Simonis Static Design RWA

53 Optimization from below Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Start with known lower bound Test value to see if problem is feasible If successful, optimal solution reached Otherwise increase bound by one and repeat Helmut Simonis Static Design RWA

54 Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Phase Finite Domain Simplified Extended Model y d {0,..., C} e E : alldifferent({y d p(d, e)}) Helmut Simonis Static Design RWA

55 SAT Model Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model d D λ,λ Λ s.t. λ λ : x λ d x λ d d D : λ Λ x λ d e E λ Λ, d, d D s.t. p(d, e) p(d, e) d d : x λ d x λ d Helmut Simonis Static Design RWA

56 SAT Solver Problem Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Use minisat as black box Generate problem file in clausal format Impose external time limit (00 sec per run) Helmut Simonis Static Design RWA 6

57 Recall: Basic Clique Sizes Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Color Off Capacity 0 unused Helmut Simonis Static Design RWA 7

58 Problem Graph Coloring Solution Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Helmut Simonis Static Design RWA 8

59 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 9

60 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 60

61 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 6

62 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 6

63 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 6

64 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 6

65 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 6

66 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 66

67 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 67

68 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 68

69 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 69

70 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 70

71 Frequency Assignment Phase MIP Phase MIP Phase Finite Domain Model Phase SAT Model Frequency Helmut Simonis Static Design RWA 7

72 Outline Problem Basic Model Extended Problem Scalability Problem Basic Model Extended Problem Scalability Helmut Simonis Static Design RWA 7

73 Example Networks Problem Basic Model Extended Problem Scalability nsf nodes, edges eon 0 nodes, 78 edges mci 9 nodes, 6 edges brezil 7 nodes, 0 edges Helmut Simonis Static Design RWA 7

74 Basic Model Extended Problem Scalability Comparison (Basic Problem, 00 Runs Each) Complete Network Dem. MIP MIP-MIP MIP-FD MIP-SAT Opt Avg Opt Avg Opt Avg Opt Avg brezil brezil brezil brezil brezil brezil eon eon eon eon eon eon mci mci mci mci mci mci nsf nsf nsf nsf nsf nsf Helmut Simonis Static Design RWA 7

75 Basic Model Extended Problem Scalability Comparison (Extended Problem, 00 Runs Each) Complete Network Dem. MIP MIP-MIP MIP-FD MIP-SAT Opt Avg Opt Avg Opt Avg Opt Avg brezil brezil brezil brezil brezil brezil eon eon eon eon eon eon mci mci mci mci mci mci nsf nsf nsf nsf nsf nsf Helmut Simonis Static Design RWA 7

76 Basic Model Extended Problem Scalability Increasing Demand Number (Extended Problem, 00 Runs Each) Network Dem. λ Opt. Avg Avg Avg Max LP Max FD Avg MIP Max MIP Avg FD Max FD LP MIP FD Gap Gap Time Time Time Time brezil brezil brezil brezil brezil brezil brezil brezil brezil brezil brezil brezil brezil brezil Helmut Simonis Static Design RWA 76

77 Basic Model Extended Problem Scalability Increasing Network Size (Extended Problem, 00 Runs Each) Network Dem. λ Opt. Avg Avg Avg Max LP Max FD Avg MIP Max MIP Avg FD Max FD LP MIP FD Gap Gap Time Time Time Time r r r r Helmut Simonis Static Design RWA 77

78 Conclusions Outline Conclusions Helmut Simonis Static Design RWA 78

79 Conclusions Conclusions Modelling static design variant of RWA Choice of objective function important Simple MIP-FD decomposition works well Very good lower bound from phase MIP/LP FD graph coloring model outperforms MIP and SAT variants Possible to use specialized graph coloring codes (not tested) Conceptually simpler than RWA demand acceptance Helmut Simonis Static Design RWA 79

Fundamentals of Integer Programming

Fundamentals of Integer Programming Fundamentals of Integer Programming Di Yuan Department of Information Technology, Uppsala University January 2018 Outline Definition of integer programming Formulating some classical problems with integer

More information

IO2654 Optical Networking. WDM network design. Lena Wosinska KTH/ICT. The aim of the next two lectures. To introduce some new definitions

IO2654 Optical Networking. WDM network design. Lena Wosinska KTH/ICT. The aim of the next two lectures. To introduce some new definitions IO2654 Optical Networking WDM network design Lena Wosinska KTH/ICT 1 The aim of the next two lectures To introduce some new definitions To make you aware about the trade-offs for WDM network design To

More information

Toward the joint design of electronic and optical layer protection

Toward the joint design of electronic and optical layer protection Toward the joint design of electronic and optical layer protection Massachusetts Institute of Technology Slide 1 Slide 2 CHALLENGES: - SEAMLESS CONNECTIVITY - MULTI-MEDIA (FIBER,SATCOM,WIRELESS) - HETEROGENEOUS

More information

Hierarchical Traffic Grooming in WDM Networks

Hierarchical Traffic Grooming in WDM Networks Hierarchical Traffic Grooming in WDM Networks George N. Rouskas Department of Computer Science North Carolina State University Joint work with: Rudra Dutta (NCSU), Bensong Chen (Google Labs), Huang Shu

More information

Column Generation Based Primal Heuristics

Column Generation Based Primal Heuristics Column Generation Based Primal Heuristics C. Joncour, S. Michel, R. Sadykov, D. Sverdlov, F. Vanderbeck University Bordeaux 1 & INRIA team RealOpt Outline 1 Context Generic Primal Heuristics The Branch-and-Price

More information

15.082J and 6.855J. Lagrangian Relaxation 2 Algorithms Application to LPs

15.082J and 6.855J. Lagrangian Relaxation 2 Algorithms Application to LPs 15.082J and 6.855J Lagrangian Relaxation 2 Algorithms Application to LPs 1 The Constrained Shortest Path Problem (1,10) 2 (1,1) 4 (2,3) (1,7) 1 (10,3) (1,2) (10,1) (5,7) 3 (12,3) 5 (2,2) 6 Find the shortest

More information

Solving a Challenging Quadratic 3D Assignment Problem

Solving a Challenging Quadratic 3D Assignment Problem Solving a Challenging Quadratic 3D Assignment Problem Hans Mittelmann Arizona State University Domenico Salvagnin DEI - University of Padova Quadratic 3D Assignment Problem Quadratic 3D Assignment Problem

More information

Hybrid Constraint Solvers

Hybrid Constraint Solvers Hybrid Constraint Solvers - An overview Why Hybrid Solvers CP and SAT: Lazy Clause Generation CP and LP: Reification of Linear Constraints Conclusions 9 November 2011 Pedro Barahona - EPCL - Hybrid Solvers

More information

Optimization Algorithms for Data Center Location Problem in Elastic Optical Networks

Optimization Algorithms for Data Center Location Problem in Elastic Optical Networks Optimization Algorithms for Data Center Location Problem in Elastic Optical Networks Mirosław Klinkowski 1, Krzysztof Walkowiak 2, and Róża Goścień 2 1 National Institute of Telecommunications, Warsaw,

More information

An Integer Programming Approach to Packing Lightpaths on WDM Networks 파장분할다중화망의광경로패킹에대한정수계획해법. 1. Introduction

An Integer Programming Approach to Packing Lightpaths on WDM Networks 파장분할다중화망의광경로패킹에대한정수계획해법. 1. Introduction Journal of the Korean Institute of Industrial Engineers Vol. 32, No. 3, pp. 219-225, September 2006. An Integer Programming Approach to Packing Lightpaths on WDM Networks Kyungsik Lee 1 Taehan Lee 2 Sungsoo

More information

An Efficient Algorithm for Solving Traffic Grooming Problems in Optical Networks

An Efficient Algorithm for Solving Traffic Grooming Problems in Optical Networks An Efficient Algorithm for Solving Traffic Grooming Problems in Optical Networks Hui Wang, George N. Rouskas Operations Research and Department of Computer Science, North Carolina State University, Raleigh,

More information

Optimization of Spectrally and Spatially Flexible Optical Networks with Spatial Mode Conversion

Optimization of Spectrally and Spatially Flexible Optical Networks with Spatial Mode Conversion 148 Regular papers ONDM 2018 Optimization of Spectrally and Spatially Flexible Optical Networks with Spatial Mode Conversion Mirosław Klinkowski, Grzegorz Zalewski, Krzysztof Walkowiak, National Institute

More information

Outline. Column Generation: Cutting Stock A very applied method. Introduction to Column Generation. Given an LP problem

Outline. Column Generation: Cutting Stock A very applied method. Introduction to Column Generation. Given an LP problem Column Generation: Cutting Stock A very applied method thst@man.dtu.dk Outline History The Simplex algorithm (re-visited) Column Generation as an extension of the Simplex algorithm A simple example! DTU-Management

More information

Column Generation: Cutting Stock

Column Generation: Cutting Stock Column Generation: Cutting Stock A very applied method thst@man.dtu.dk DTU-Management Technical University of Denmark 1 Outline History The Simplex algorithm (re-visited) Column Generation as an extension

More information

4.1 Interval Scheduling

4.1 Interval Scheduling 41 Interval Scheduling Interval Scheduling Interval scheduling Job j starts at s j and finishes at f j Two jobs compatible if they don't overlap Goal: find maximum subset of mutually compatible jobs a

More information

Lecture 14: Linear Programming II

Lecture 14: Linear Programming II A Theorist s Toolkit (CMU 18-859T, Fall 013) Lecture 14: Linear Programming II October 3, 013 Lecturer: Ryan O Donnell Scribe: Stylianos Despotakis 1 Introduction At a big conference in Wisconsin in 1948

More information

OPTICAL NETWORKS. Virtual Topology Design. A. Gençata İTÜ, Dept. Computer Engineering 2005

OPTICAL NETWORKS. Virtual Topology Design. A. Gençata İTÜ, Dept. Computer Engineering 2005 OPTICAL NETWORKS Virtual Topology Design A. Gençata İTÜ, Dept. Computer Engineering 2005 Virtual Topology A lightpath provides single-hop communication between any two nodes, which could be far apart in

More information

Link Selection Algorithms for Link-Based ILPs and Applications to RWA in Mesh Networks

Link Selection Algorithms for Link-Based ILPs and Applications to RWA in Mesh Networks Link Selection Algorithms for Link-Based ILPs and Applications to RWA in Mesh Networks Zeyu Liu, George N. Rouskas Department of Computer Science, North Carolina State University, Raleigh, NC 27695-8206,

More information

Maximization of Single Hop Traffic with Greedy Heuristics

Maximization of Single Hop Traffic with Greedy Heuristics Maximization of Single Hop Traffic with Greedy Heuristics Esa Hyytiä Networking Laboratory, HUT, Finland, email: esa@netlab.hut.fi, ABSTRACT Maximization of the single hop traffic has been proposed as

More information

Dynamic Wavelength Assignment for WDM All-Optical Tree Networks

Dynamic Wavelength Assignment for WDM All-Optical Tree Networks Dynamic Wavelength Assignment for WDM All-Optical Tree Networks Poompat Saengudomlert, Eytan H. Modiano, and Robert G. Gallager Laboratory for Information and Decision Systems Massachusetts Institute of

More information

Design of Large-Scale Optical Networks Λ

Design of Large-Scale Optical Networks Λ Design of Large-Scale Optical Networks Λ Yufeng Xin, George N. Rouskas, Harry G. Perros Department of Computer Science, North Carolina State University, Raleigh NC 27695 E-mail: fyxin,rouskas,hpg@eos.ncsu.edu

More information

An Ant Colony Optimization Implementation for Dynamic Routing and Wavelength Assignment in Optical Networks

An Ant Colony Optimization Implementation for Dynamic Routing and Wavelength Assignment in Optical Networks An Ant Colony Optimization Implementation for Dynamic Routing and Wavelength Assignment in Optical Networks Timothy Hahn, Shen Wan March 5, 2008 Montana State University Computer Science Department Bozeman,

More information

Discrete Optimization with Decision Diagrams

Discrete Optimization with Decision Diagrams Discrete Optimization with Decision Diagrams J. N. Hooker Joint work with David Bergman, André Ciré, Willem van Hoeve Carnegie Mellon University Australian OR Society, May 2014 Goal Find an alternative

More information

Solving a Challenging Quadratic 3D Assignment Problem

Solving a Challenging Quadratic 3D Assignment Problem Solving a Challenging Quadratic 3D Assignment Problem Hans Mittelmann Arizona State University Domenico Salvagnin DEI - University of Padova Quadratic 3D Assignment Problem Quadratic 3D Assignment Problem

More information

Modelling with Constraints

Modelling with Constraints Masterclass Modelling with Constraints Part 1: Introduction Alan M Frisch Artificial Intelligence Group Dept of Computer Science University of York 12 December 2011 1 Motivation A modern generation of

More information

Improved Gomory Cuts for Primal Cutting Plane Algorithms

Improved Gomory Cuts for Primal Cutting Plane Algorithms Improved Gomory Cuts for Primal Cutting Plane Algorithms S. Dey J-P. Richard Industrial Engineering Purdue University INFORMS, 2005 Outline 1 Motivation The Basic Idea Set up the Lifting Problem How to

More information

MVE165/MMG630, Applied Optimization Lecture 8 Integer linear programming algorithms. Ann-Brith Strömberg

MVE165/MMG630, Applied Optimization Lecture 8 Integer linear programming algorithms. Ann-Brith Strömberg MVE165/MMG630, Integer linear programming algorithms Ann-Brith Strömberg 2009 04 15 Methods for ILP: Overview (Ch. 14.1) Enumeration Implicit enumeration: Branch and bound Relaxations Decomposition methods:

More information

Course Summary! What have we learned and what are we expected to know?

Course Summary! What have we learned and what are we expected to know? Course Summary! What have we learned and what are we expected to know? Overview! Introduction Modelling in MiniZinc Finite Domain Constraint Solving Search Linear Programming and Network Flow Mixed Integer

More information

Performance Analysis of Storage-Based Routing for Circuit-Switched Networks [1]

Performance Analysis of Storage-Based Routing for Circuit-Switched Networks [1] Performance Analysis of Storage-Based Routing for Circuit-Switched Networks [1] Presenter: Yongcheng (Jeremy) Li PhD student, School of Electronic and Information Engineering, Soochow University, China

More information

3 No-Wait Job Shops with Variable Processing Times

3 No-Wait Job Shops with Variable Processing Times 3 No-Wait Job Shops with Variable Processing Times In this chapter we assume that, on top of the classical no-wait job shop setting, we are given a set of processing times for each operation. We may select

More information

Designing WDM Optical Networks using Branch-and-Price

Designing WDM Optical Networks using Branch-and-Price Designing WDM Optical Networks using Branch-and-Price S. Raghavan Smith School of Business & Institute for Systems Research University of Maryland College Park, MD 20742 raghavan@umd.edu Daliborka Stanojević

More information

Subset sum problem and dynamic programming

Subset sum problem and dynamic programming Lecture Notes: Dynamic programming We will discuss the subset sum problem (introduced last time), and introduce the main idea of dynamic programming. We illustrate it further using a variant of the so-called

More information

A Routing and Network Dimensioning Strategy to reduce Wavelength Continuity Conflicts in All-Optical Networks

A Routing and Network Dimensioning Strategy to reduce Wavelength Continuity Conflicts in All-Optical Networks A Routing and Network Dimensioning Strategy to reduce Wavelength Continuity Conflicts in All-Optical Networks Arie M.C.A. Koster, Zuse Institute Berlin (ZIB), Takustr. 7, D-495 Berlin, koster@zib.de Matthias

More information

Introduction to Mathematical Programming IE406. Lecture 20. Dr. Ted Ralphs

Introduction to Mathematical Programming IE406. Lecture 20. Dr. Ted Ralphs Introduction to Mathematical Programming IE406 Lecture 20 Dr. Ted Ralphs IE406 Lecture 20 1 Reading for This Lecture Bertsimas Sections 10.1, 11.4 IE406 Lecture 20 2 Integer Linear Programming An integer

More information

Rollout Algorithms for Logical Topology Design and Traffic Grooming in Multihop WDM Networks

Rollout Algorithms for Logical Topology Design and Traffic Grooming in Multihop WDM Networks Rollout Algorithms for Logical Topology Design and Traffic Grooming in Multihop WDM Networks Kwangil Lee Department of Electrical and Computer Engineering University of Texas, El Paso, TX 79928, USA. Email:

More information

DYN-OPT Users Manual. Cenk Caliskan Randolph W. Hall. California PATH Working Paper UCB-ITS-PWP-97-6

DYN-OPT Users Manual. Cenk Caliskan Randolph W. Hall. California PATH Working Paper UCB-ITS-PWP-97-6 CALIFORNIA PATH PROGRAM INSTITUTE OF TRANSPORTATION STUDIES UNIVERSITY OF CALIFORNIA, BERKELEY DYN-OPT Users Manual Cenk Caliskan Randolph W Hall California PATH Working Paper UCB-ITS-PWP-97-6 This work

More information

Combinatorial Optimization

Combinatorial Optimization Combinatorial Optimization Frank de Zeeuw EPFL 2012 Today Introduction Graph problems - What combinatorial things will we be optimizing? Algorithms - What kind of solution are we looking for? Linear Programming

More information

Efficient Data Movement on the Grid

Efficient Data Movement on the Grid Efficient Data Movement on the Grid Michal Zerola for the STAR collaboration Jérôme Lauret, Roman Barták and Michal Šumbera michal.zerola@ujf.cas.cz NPI, AS CR CFRJS - FJFI, February 13, 2009 Michal Zerola

More information

Integer Programming ISE 418. Lecture 1. Dr. Ted Ralphs

Integer Programming ISE 418. Lecture 1. Dr. Ted Ralphs Integer Programming ISE 418 Lecture 1 Dr. Ted Ralphs ISE 418 Lecture 1 1 Reading for This Lecture N&W Sections I.1.1-I.1.4 Wolsey Chapter 1 CCZ Chapter 2 ISE 418 Lecture 1 2 Mathematical Optimization Problems

More information

Wavelength Assignment in a Ring Topology for Wavelength Routed WDM Optical Networks

Wavelength Assignment in a Ring Topology for Wavelength Routed WDM Optical Networks Wavelength Assignment in a Ring Topology for Wavelength Routed WDM Optical Networks Amit Shukla, L. Premjit Singh and Raja Datta, Dept. of Computer Science and Engineering, North Eastern Regional Institute

More information

Batch Scheduling Algorithms for Optical Burst Switching Networks

Batch Scheduling Algorithms for Optical Burst Switching Networks Batch Scheduling Algorithms for Optical Burst Switching Networks Ayman Kaheel and Hussein Alnuweiri University of British Columbia, Vancouver BC V6T 1Z4, Canada, {aymank,hussein}@ece.ubc.ca Abstract. Previously

More information

WDM Network Provisioning

WDM Network Provisioning IO2654 Optical Networking WDM Network Provisioning Paolo Monti Optical Networks Lab (ONLab), Communication Systems Department (COS) http://web.it.kth.se/~pmonti/ Some of the material is taken from the

More information

The Ascendance of the Dual Simplex Method: A Geometric View

The Ascendance of the Dual Simplex Method: A Geometric View The Ascendance of the Dual Simplex Method: A Geometric View Robert Fourer 4er@ampl.com AMPL Optimization Inc. www.ampl.com +1 773-336-AMPL U.S.-Mexico Workshop on Optimization and Its Applications Huatulco

More information

A Modified Heuristic Approach of Logical Topology Design in WDM Optical Networks

A Modified Heuristic Approach of Logical Topology Design in WDM Optical Networks Proceedings of the International Conference on Computer and Communication Engineering 008 May 3-5, 008 Kuala Lumpur, Malaysia A Modified Heuristic Approach of Logical Topology Design in WDM Optical Networks

More information

Graph Theory and Optimization Approximation Algorithms

Graph Theory and Optimization Approximation Algorithms Graph Theory and Optimization Approximation Algorithms Nicolas Nisse Université Côte d Azur, Inria, CNRS, I3S, France October 2018 Thank you to F. Giroire for some of the slides N. Nisse Graph Theory and

More information

WDM Network Provisioning

WDM Network Provisioning IO2654 Optical Networking WDM Network Provisioning Paolo Monti Optical Networks Lab (ONLab), Communication Systems Department (COS) http://web.it.kth.se/~pmonti/ Some of the material is taken from the

More information

Efficient decomposition method for the stochastic optimization of public transport schedules

Efficient decomposition method for the stochastic optimization of public transport schedules Efficient decomposition method for the stochastic optimization of public transport schedules Sofia Zaourar-Michel Xerox Research Centre Europe sofia.michel@xrce.xerox.com Abstract We propose a new method

More information

A List Heuristic for Vertex Cover

A List Heuristic for Vertex Cover A List Heuristic for Vertex Cover Happy Birthday Vasek! David Avis McGill University Tomokazu Imamura Kyoto University Operations Research Letters (to appear) Online: http://cgm.cs.mcgill.ca/ avis revised:

More information

Lecture 7: Asymmetric K-Center

Lecture 7: Asymmetric K-Center Advanced Approximation Algorithms (CMU 18-854B, Spring 008) Lecture 7: Asymmetric K-Center February 5, 007 Lecturer: Anupam Gupta Scribe: Jeremiah Blocki In this lecture, we will consider the K-center

More information

Solving lexicographic multiobjective MIPs with Branch-Cut-Price

Solving lexicographic multiobjective MIPs with Branch-Cut-Price Solving lexicographic multiobjective MIPs with Branch-Cut-Price Marta Eso (The Hotchkiss School) Laszlo Ladanyi (IBM T.J. Watson Research Center) David Jensen (IBM T.J. Watson Research Center) McMaster

More information

Distributed Clustering Method for Large-Scaled Wavelength-Routed Networks

Distributed Clustering Method for Large-Scaled Wavelength-Routed Networks Distributed Clustering Method for Large-Scaled Wavelength-Routed Networks Yukinobu Fukushima Graduate School of Information and Computer Science Osaka University, Japan 1 Background: Inter-Domain Wavelength-Routed

More information

Session Directories and Multicast Address Allocation

Session Directories and Multicast Address Allocation Session Directories and Multicast Address Allocation Mark Handley USC/ISI mjh@isi.edu A Little History The first multicast session directory was sd from Van Jacobson and Steve McCanne at LBNL in 1992.

More information

College of Computer & Information Science Fall 2007 Northeastern University 14 September 2007

College of Computer & Information Science Fall 2007 Northeastern University 14 September 2007 College of Computer & Information Science Fall 2007 Northeastern University 14 September 2007 CS G399: Algorithmic Power Tools I Scribe: Eric Robinson Lecture Outline: Linear Programming: Vertex Definitions

More information

Design and Analysis of Algorithms

Design and Analysis of Algorithms CSE 101, Winter 018 D/Q Greed SP s DP LP, Flow B&B, Backtrack Metaheuristics P, NP Design and Analysis of Algorithms Lecture 8: Greed Class URL: http://vlsicad.ucsd.edu/courses/cse101-w18/ Optimization

More information

Modelling of LP-problems (2WO09)

Modelling of LP-problems (2WO09) Modelling of LP-problems (2WO09) assignor: Judith Keijsper room: HG 9.31 email: J.C.M.Keijsper@tue.nl course info : http://www.win.tue.nl/ jkeijspe Technische Universiteit Eindhoven meeting 1 J.Keijsper

More information

Optimal Network Flow Allocation. EE 384Y Almir Mutapcic and Primoz Skraba 27/05/2004

Optimal Network Flow Allocation. EE 384Y Almir Mutapcic and Primoz Skraba 27/05/2004 Optimal Network Flow Allocation EE 384Y Almir Mutapcic and Primoz Skraba 27/05/2004 Problem Statement Optimal network flow allocation Find flow allocation which minimizes certain performance criterion

More information

Some economical principles

Some economical principles Hints on capacity planning (and other approaches) Andrea Bianco Telecommunication Network Group firstname.lastname@polito.it http://www.telematica.polito.it/ Some economical principles Assume users have

More information

PART II: Local Consistency & Constraint Propagation

PART II: Local Consistency & Constraint Propagation PART II: Local Consistency & Constraint Propagation Solving CSPs Search algorithm. Usually backtracking search performing a depth-first traversal of a search tree. Local consistency and constraint propagation.

More information

Recursive column generation for the Tactical Berth Allocation Problem

Recursive column generation for the Tactical Berth Allocation Problem Recursive column generation for the Tactical Berth Allocation Problem Ilaria Vacca 1 Matteo Salani 2 Michel Bierlaire 1 1 Transport and Mobility Laboratory, EPFL, Lausanne, Switzerland 2 IDSIA, Lugano,

More information

Algorithms for Decision Support. Integer linear programming models

Algorithms for Decision Support. Integer linear programming models Algorithms for Decision Support Integer linear programming models 1 People with reduced mobility (PRM) require assistance when travelling through the airport http://www.schiphol.nl/travellers/atschiphol/informationforpassengerswithreducedmobility.htm

More information

The Size Robust Multiple Knapsack Problem

The Size Robust Multiple Knapsack Problem MASTER THESIS ICA-3251535 The Size Robust Multiple Knapsack Problem Branch and Price for the Separate and Combined Recovery Decomposition Model Author: D.D. Tönissen, Supervisors: dr. ir. J.M. van den

More information

TIM 206 Lecture Notes Integer Programming

TIM 206 Lecture Notes Integer Programming TIM 206 Lecture Notes Integer Programming Instructor: Kevin Ross Scribe: Fengji Xu October 25, 2011 1 Defining Integer Programming Problems We will deal with linear constraints. The abbreviation MIP stands

More information

Approximation Algorithms

Approximation Algorithms Approximation Algorithms Frédéric Giroire FG Simplex 1/11 Motivation Goal: Find good solutions for difficult problems (NP-hard). Be able to quantify the goodness of the given solution. Presentation of

More information

Math Models of OR: The Simplex Algorithm: Practical Considerations

Math Models of OR: The Simplex Algorithm: Practical Considerations Math Models of OR: The Simplex Algorithm: Practical Considerations John E. Mitchell Department of Mathematical Sciences RPI, Troy, NY 12180 USA September 2018 Mitchell Simplex Algorithm: Practical Considerations

More information

Heuristic Optimisation

Heuristic Optimisation Heuristic Optimisation Part 3: Classification of algorithms. Exhaustive search Sándor Zoltán Németh http://web.mat.bham.ac.uk/s.z.nemeth s.nemeth@bham.ac.uk University of Birmingham S Z Németh (s.nemeth@bham.ac.uk)

More information

TRAFFIC GROOMING WITH BLOCKING PROBABILITY REDUCTION IN DYNAMIC OPTICAL WDM NETWORKS

TRAFFIC GROOMING WITH BLOCKING PROBABILITY REDUCTION IN DYNAMIC OPTICAL WDM NETWORKS TRAFFIC GROOMING WITH BLOCKING PROBABILITY REDUCTION IN DYNAMIC OPTICAL WDM NETWORKS K.Pushpanathan 1, Dr.A.Sivasubramanian 2 1 Asst Prof, Anand Institute of Higher Technology, Chennai-603103 2 Prof &

More information

Using SAS/OR to Optimize Scheduling and Routing of Service Vehicles

Using SAS/OR to Optimize Scheduling and Routing of Service Vehicles Paper SAS1758-2018 Using SAS/OR to Optimize Scheduling and Routing of Service Vehicles Rob Pratt, SAS Institute Inc. ABSTRACT An oil company has a set of wells and a set of well operators. Each well has

More information

Wireless frequency auctions: Mixed Integer Programs and Dantzig-Wolfe decomposition

Wireless frequency auctions: Mixed Integer Programs and Dantzig-Wolfe decomposition Wireless frequency auctions: Mixed Integer Programs and Dantzig-Wolfe decomposition Laszlo Ladanyi (IBM T.J. Watson Research Center) joint work with Marta Eso (The Hotchkiss School) David Jensen (IBM T.J.

More information

Iterative Optimization in VTD to Maximize the Open Capacity of WDM Networks

Iterative Optimization in VTD to Maximize the Open Capacity of WDM Networks Iterative Optimization in VTD to Maximize the Open Capacity of WDM Networks Karcius D.R. Assis, Marcio S. Savasini and Helio Waldman DECOM/FEEC/UNICAMP, CP. 6101, 13083-970 Campinas, SP-BRAZIL Tel: +55-19-37883793,

More information

(Stochastic) Local Search Algorithms

(Stochastic) Local Search Algorithms DM841 DISCRETE OPTIMIZATION Part 2 Heuristics (Stochastic) Marco Chiarandini Department of Mathematics & Computer Science University of Southern Denmark Outline 1. 2. 3. Components 2 Outline 1. 2. 3. Components

More information

Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics

Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics Two-layer Network Design by Branch-and-Cut featuring MIP-based Heuristics Sebastian Orlowski, Zuse Institute Berlin, Takustr. 7, D-14195 Berlin, orlowski@zib.de Arie M.C.A. Koster, Zuse Institute Berlin,

More information

Approximation Algorithms

Approximation Algorithms Approximation Algorithms Given an NP-hard problem, what should be done? Theory says you're unlikely to find a poly-time algorithm. Must sacrifice one of three desired features. Solve problem to optimality.

More information

Capacity planning and.

Capacity planning and. Hints on capacity planning (and other approaches) Andrea Bianco Telecommunication Network Group firstname.lastname@polito.it http://www.telematica.polito.it/ Some economical principles Assume users have

More information

Agenda. Understanding advanced modeling techniques takes some time and experience No exercises today Ask questions!

Agenda. Understanding advanced modeling techniques takes some time and experience No exercises today Ask questions! Modeling 2 Agenda Understanding advanced modeling techniques takes some time and experience No exercises today Ask questions! Part 1: Overview of selected modeling techniques Background Range constraints

More information

A Computational Study of Conflict Graphs and Aggressive Cut Separation in Integer Programming

A Computational Study of Conflict Graphs and Aggressive Cut Separation in Integer Programming A Computational Study of Conflict Graphs and Aggressive Cut Separation in Integer Programming Samuel Souza Brito and Haroldo Gambini Santos 1 Dep. de Computação, Universidade Federal de Ouro Preto - UFOP

More information

THE CONSTRAINT PROGRAMMER S TOOLBOX. Christian Schulte, SCALE, KTH & SICS

THE CONSTRAINT PROGRAMMER S TOOLBOX. Christian Schulte, SCALE, KTH & SICS THE CONSTRAINT PROGRAMMER S TOOLBOX Christian Schulte, SCALE, KTH & SICS Constraint Programming 2 What is constraint programming? Sudoku is constraint programming 3 Sudoku...is constraint programming!

More information

Computational Complexity CSC Professor: Tom Altman. Capacitated Problem

Computational Complexity CSC Professor: Tom Altman. Capacitated Problem Computational Complexity CSC 5802 Professor: Tom Altman Capacitated Problem Agenda: Definition Example Solution Techniques Implementation Capacitated VRP (CPRV) CVRP is a Vehicle Routing Problem (VRP)

More information

DEPARTMENT OF ELECTRONIC SYSTEMS ENGINEERING

DEPARTMENT OF ELECTRONIC SYSTEMS ENGINEERING DEPARTMENT OF ELECTRONIC SYSTEMS ENGINEERING OPTICAL NETWORK DESIGN : VIRTUAL TOPOLOGY AND WAVELENGTH ASSIGNMENT USING LINEAR PROGRAMMING DAMIANOS GAVALAS MSc in Telecommunications & Information Systems

More information

GENERAL ASSIGNMENT PROBLEM via Branch and Price JOHN AND LEI

GENERAL ASSIGNMENT PROBLEM via Branch and Price JOHN AND LEI GENERAL ASSIGNMENT PROBLEM via Branch and Price JOHN AND LEI Outline Review the column generation in Generalized Assignment Problem (GAP) GAP Examples in Branch and Price 2 Assignment Problem The assignment

More information

Improving Dual Bound for Stochastic MILP Models Using Sensitivity Analysis

Improving Dual Bound for Stochastic MILP Models Using Sensitivity Analysis Improving Dual Bound for Stochastic MILP Models Using Sensitivity Analysis Vijay Gupta Ignacio E. Grossmann Department of Chemical Engineering Carnegie Mellon University, Pittsburgh Bora Tarhan ExxonMobil

More information

Constraint (Logic) Programming

Constraint (Logic) Programming Constraint (Logic) Programming Roman Barták Faculty of Mathematics and Physics, Charles University in Prague, Czech Republic bartak@ktiml.mff.cuni.cz Sudoku Combinatorial puzzle, whose goal is to enter

More information

CS 580: Algorithm Design and Analysis. Jeremiah Blocki Purdue University Spring 2018

CS 580: Algorithm Design and Analysis. Jeremiah Blocki Purdue University Spring 2018 CS 580: Algorithm Design and Analysis Jeremiah Blocki Purdue University Spring 2018 Chapter 11 Approximation Algorithms Slides by Kevin Wayne. Copyright @ 2005 Pearson-Addison Wesley. All rights reserved.

More information

QoS routing in DWDM Optical Packet Networks

QoS routing in DWDM Optical Packet Networks QoS routing in DWDM Optical Packet Networks W. Cerroni CNIT Bologna Research Unit, ITALY F. Callegati, G. Muretto, C. Raffaelli, P. Zaffoni DEIS University of Bologna, ITALY Optical Packet Switching (OPS)

More information

The Gurobi Solver V1.0

The Gurobi Solver V1.0 The Gurobi Solver V1.0 Robert E. Bixby Gurobi Optimization & Rice University Ed Rothberg, Zonghao Gu Gurobi Optimization 1 1 Oct 09 Overview Background Rethinking the MIP solver Introduction Tree of Trees

More information

A Comparison of Mixed-Integer Programming Models for Non-Convex Piecewise Linear Cost Minimization Problems

A Comparison of Mixed-Integer Programming Models for Non-Convex Piecewise Linear Cost Minimization Problems A Comparison of Mixed-Integer Programming Models for Non-Convex Piecewise Linear Cost Minimization Problems Keely L. Croxton Fisher College of Business The Ohio State University Bernard Gendron Département

More information

3 INTEGER LINEAR PROGRAMMING

3 INTEGER LINEAR PROGRAMMING 3 INTEGER LINEAR PROGRAMMING PROBLEM DEFINITION Integer linear programming problem (ILP) of the decision variables x 1,..,x n : (ILP) subject to minimize c x j j n j= 1 a ij x j x j 0 x j integer n j=

More information

Optimal network flow allocation

Optimal network flow allocation Optimal network flow allocation EE384Y Project intermediate report Almir Mutapcic and Primoz Skraba Stanford University, Spring 2003-04 May 10, 2004 Contents 1 Introduction 2 2 Background 2 3 Problem statement

More information

Branch-price-and-cut for vehicle routing. Guy Desaulniers

Branch-price-and-cut for vehicle routing. Guy Desaulniers Guy Desaulniers Professor, Polytechnique Montréal, Canada Director, GERAD, Canada VeRoLog PhD School 2018 Cagliari, Italy, June 2, 2018 Outline 1 VRPTW definition 2 Mathematical formulations Arc-flow formulation

More information

System Description of a SAT-based CSP Solver Sugar

System Description of a SAT-based CSP Solver Sugar System Description of a SAT-based CSP Solver Sugar Naoyuki Tamura 1, Tomoya Tanjo 2, and Mutsunori Banbara 1 1 Information Science and Technology Center, Kobe University, JAPAN {tamura,banbara}@kobe-u.ac.jp

More information

Exploring Performance Tradeoffs in a Sudoku SAT Solver CS242 Project Report

Exploring Performance Tradeoffs in a Sudoku SAT Solver CS242 Project Report Exploring Performance Tradeoffs in a Sudoku SAT Solver CS242 Project Report Hana Lee (leehana@stanford.edu) December 15, 2017 1 Summary I implemented a SAT solver capable of solving Sudoku puzzles using

More information

Questions? You are given the complete graph of Facebook. What questions would you ask? (What questions could we hope to answer?)

Questions? You are given the complete graph of Facebook. What questions would you ask? (What questions could we hope to answer?) P vs. NP What now? Attribution These slides were prepared for the New Jersey Governor s School course The Math Behind the Machine taught in the summer of 2011 by Grant Schoenebeck Large parts of these

More information

CSE 417 Branch & Bound (pt 4) Branch & Bound

CSE 417 Branch & Bound (pt 4) Branch & Bound CSE 417 Branch & Bound (pt 4) Branch & Bound Reminders > HW8 due today > HW9 will be posted tomorrow start early program will be slow, so debugging will be slow... Review of previous lectures > Complexity

More information

MODERN communication networks are constructed

MODERN communication networks are constructed 1000 IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 19, NO. 4, AUGUST 2011 Cross-Layer Survivability in WDM-Based Networks Kayi Lee, Member, IEEE, Eytan Modiano, Senior Member, IEEE, and Hyang-Won Lee, Member,

More information

A Branch-and-Cut Algorithm for the Partition Coloring Problem

A Branch-and-Cut Algorithm for the Partition Coloring Problem A Branch-and-Cut Algorithm for the Partition Coloring Problem Yuri Frota COPPE/UFRJ, Programa de Engenharia de Sistemas e Otimização Rio de Janeiro, RJ 21945-970, Brazil abitbol@cos.ufrj.br Nelson Maculan

More information

Final Exam Spring 2003

Final Exam Spring 2003 .8 Final Exam Spring Name Instructions.. Please answer all questions in the exam books that are provided.. Please budget your time carefully. It is often a good idea to read the entire exam first, so that

More information

Routing and Wavelength Assignment in Optical Networks 1

Routing and Wavelength Assignment in Optical Networks 1 Routing and Wavelength Assignment in Optical Networks 1 by Asuman E. Ozdaglar and Dimitri P. Bertsekas 2 Abstract The problem of routing and wavelength assignment (RWA) is critically important for increasing

More information

Applied Lagrange Duality for Constrained Optimization

Applied Lagrange Duality for Constrained Optimization Applied Lagrange Duality for Constrained Optimization Robert M. Freund February 10, 2004 c 2004 Massachusetts Institute of Technology. 1 1 Overview The Practical Importance of Duality Review of Convexity

More information

Lagrangian Relaxation in CP

Lagrangian Relaxation in CP Lagrangian Relaxation in CP Willem-Jan van Hoeve CPAIOR 016 Master Class Overview 1. Motivation for using Lagrangian Relaxations in CP. Lagrangian-based domain filtering Example: Traveling Salesman Problem.

More information

Motivation for Heuristics

Motivation for Heuristics MIP Heuristics 1 Motivation for Heuristics Why not wait for branching? Produce feasible solutions as quickly as possible Often satisfies user demands Avoid exploring unproductive sub trees Better reduced

More information

THE CONSTRAINT PROGRAMMER S TOOLBOX. Christian Schulte, SCALE, KTH & SICS

THE CONSTRAINT PROGRAMMER S TOOLBOX. Christian Schulte, SCALE, KTH & SICS THE CONSTRAINT PROGRAMMER S TOOLBOX Christian Schulte, SCALE, KTH & SICS Constraint Programming 2 What is constraint programming? Sudoku is constraint programming 3 Sudoku...is constraint programming!

More information