A library of local search heuristics for the vehicle routing problem

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 allows 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 optionswithminimal code change. The code iswell-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. The manuscript submitted by Chris Groër has been authored by a contractor of the U.S. Government under Contract No. DE-AC05-00OR22725. Accordingly, the U.S. Government retains a non-exclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. Edward Wasil was supported in part by a Kogod Research Professorship at American University. C. Groër (B) Oak Ridge National Laboratory, 1 Bethel Valley Rd, Oak Ridge, TN 37831, USA e-mail: [email protected] B. Golden R.H. Smith School of Business, University of Maryland, College Park, MD 20742, USA e-mail: [email protected] E. Wasil Kogod School of Business, American University, Washington, DC 20016, USA e-mail: [email protected]