North West

In: Computers and Technology

Submitted By rachana215
Words 10780
Pages 44
A Library of Local Search Heuristics for the Vehicle
Routing Problem
Chris Gro¨r1 e Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831 cgroer@gmail.com Bruce Golden
R.H. Smith School of Business, University of Maryland, College Park, MD 20742, USA, bgolden@rhsmith.umd.edu Edward Wasil2
Kogod School of Business, American University, Washington, DC 20016, USA, ewasil@american.edu The vehicle routing problem (VRP) is a difficult and well-studied combinatorial optimization problem. Real-world instances of the VRP can contain hundreds and even thousands of customer locations and can involve many complicating constraints, necessitating the use of heuristic methods. We present a software library of local search heuristics that allow one to quickly generate solutions to VRP instances. The code has a logical, object-oriented design and uses efficient data structures to store and modify solutions. The core of the library is the implementation of seven local search operators that share a similar interface and are designed to be extended to handle additional options with minimal code change. The code is well-documented, straightforward to compile, and is freely available online. The code contains several applications that can be used to generate solutions to the capacitated VRP. Computational results indicate that these applications are able to generate solutions that are within about one percent of the best-known solution on benchmark problems.
Key words: vehicle routing; optimization; heuristics; metaheuristics;
History: Submitted December 2008, Reviews received May 2009, Revised January 2010

1.

Introduction

In the classical capacitated Vehicle Routing Problem (VRP), a minimum cost set of routes is constructed for a fleet of identical vehicles. These routes must satisfy the demands of all
1

The submitted manuscript has been authored by a contractor of the…...

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