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90 lines
4.1 KiB
Markdown
90 lines
4.1 KiB
Markdown
This example covers:
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- defining and creating different 'depots', vehicles and their types
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- defining a problem with finite fleet-size
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- reading and creating an algorithm
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- plotting the solution
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It is based on the problem instance P08 defined by
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<em>Cordeau, J.-F., Gendreau, M. and Laporte, G. (1997), A tabu search heuristic for periodic and multi-depot vehicle routing problems. Networks, 30: 105–119.</em>
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Please visit for example <a href="http://neo.lcc.uma.es/vrp/vrp-flavors/multiple-depot-vrp/" target="_blank">this site</a> to get more information on Multiple Depot VRP.
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Before you start, [add the latest release to your pom](Add-latest-release-to-your-pom.md). Additionally, create an output folder in your project directory. Either do it manually or add the following lines to your code:
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<pre><code>File dir = new File("output");
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// if the directory does not exist, create it
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if (!dir.exists()){
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System.out.println("creating directory ./output");
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boolean result = dir.mkdir();
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if(result) System.out.println("./output created");
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}
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</code></pre>
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All services of P08 are stored in an xml-file called vrp_cordeau_08.xml (you can find it [here](https://github.com/jsprit/jsprit/tree/master/jsprit-examples/input)). You read them into your problemBuilder as follows
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<pre><code>VehicleRoutingProblem.Builder vrpBuilder = VehicleRoutingProblem.Builder.newInstance();
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/*
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* Read cordeau-instance p08, BUT only its services without any vehicles
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*/
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new VrpXMLReader(vrpBuilder).read("input/vrp_cordeau_08.xml");
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</code></pre>
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Define depots and vehicles:
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<pre><code>/*
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* add vehicles with its depots
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* 2 depots with the following coordinates:
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* (-33,33), (33,-33)
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*
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* each with 14 vehicles each with a capacity of 500 and a maximum duration of 310
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*/
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int nuOfVehicles = 14;
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int capacity = 500;
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double maxDuration = 310;
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Coordinate firstDepotCoord = Coordinate.newInstance(-33, 33);
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Coordinate second = Coordinate.newInstance(33, -33);
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int depotCounter = 1;
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for(Coordinate depotCoord : Arrays.asList(firstDepotCoord,second)){
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for(int i=0;i<nuOfVehicles;i++){
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String typeId = depotCounter + "_type";
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VehicleType vehicleType = VehicleTypeImpl.Builder.newInstance(typeId).addCapacityDimension(0,capacity).setCostPerDistance(1.0).build();
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String vehicleId = depotCounter + "_" + (i+1) + "_vehicle";
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VehicleImpl.VehicleBuilder vehicleBuilder = VehicleImpl.Builder.newInstance(vehicleId);
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vehicleBuilder.setStartLocation(depotCoord); //defines the location of the vehicle and thus the depot
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vehicleBuilder.setType(vehicleType)
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vehicleBuilder.setLatestArrival(maxDuration);
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Vehicle vehicle = vehicleBuilder.build();
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vrpBuilder.addVehicle(vehicle);
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}
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depotCounter++;
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}
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</code></pre>
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Build the problem, and define and run an algorithm like this:
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<pre><code>
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/*
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* define problem with finite fleet
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*/
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vrpBuilder.setFleetSize(FleetSize.FINITE);
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/*
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* build the problem
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*/
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VehicleRoutingProblem vrp = vrpBuilder.build();
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/*
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* solve the problem
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*/
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VehicleRoutingAlgorithm vra = VehicleRoutingAlgorithms.readAndCreateAlgorithm(vrp,"input/algorithmConfig.xml");
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Collection<VehicleRoutingProblemSolution> solutions = vra.searchSolutions();
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</code></pre>
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The problem will be looking like this:
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Running <a href="https://github.com/jsprit/jsprit/blob/master/jsprit-examples/input/algorithmConfig.xml" target="_blank">this algorithm</a> yields to the following solution:
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You can find the entire code <a href="https://github.com/jsprit/jsprit/blob/v1.4/jsprit-examples/src/main/java/jsprit/examples/MultipleDepotExampleWithPenaltyVehicles.java" target="_blank">here</a>.
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