work in progres ...

= How to … implement a new VRP ProblemInstance =

== Goals ==

One way to implement a new VRP variant is by implementing a new {{{VRPProblemInstance}}}. This is a suitable possibility if the VRP variant requires additional model data. A {{{VRPProblemInstance}}} is responsible for storing all information about a VRP instance like coordinates, distances, demands, etc. By extending a {{{VRPProblemInstance}}} it is possible to add additional data as additional constraints or flexibility to a VRP variant. It is also necessary to implement a new {{{VRPEvaluator}}} (see [wiki:UsersHowtosImplementANewVRPEvaluator How to ... implement a new VRP Evaluator]) to interpret the new data.

In addition to the new {{{VRPProblemInstance}}} a new ''parser'' for reading the additional data from a file is required. In order to integrate the new parser into HeuristicLab a {{{VRPInstanceProvider}}} and other components are also required.

After this tutorial you will be able to implement you own VRP variants that require additional model data. You will also have a basic understanding of the concepts and architecture concerning the {{{VRPProblemInstance}}}, the {{{VRPInstanceProvider}}} and related components.