This example covers:
- defining and creating different 'depots', vehicles and their types
- defining a problem with finite fleet-size
- reading and creating an algorithm
- plotting the solution
It is based on the problem instance P01 defined by
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.
Please visit for example this site to get more information on Multiple Depot VRP.
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 (even this obfuscates the code-example a bit):
File dir = new File("output");
// if the directory does not exist, create it
if (!dir.exists()){
System.out.println("creating directory ./output");
boolean result = dir.mkdir();
if(result) System.out.println("./output created");
}
All services of P01 are stored in an xml-file called vrp_cordeau_01.xml (you can find it [here](https://github.com/jsprit/jsprit/tree/master/jsprit-examples/input)). To read them into your problemBuilder, code the following lines:
VehicleRoutingProblem.Builder vrpBuilder = VehicleRoutingProblem.Builder.newInstance();
/*
* Read cordeau-instance p01, BUT only its services without any vehicles
*/
new VrpXMLReader(vrpBuilder).read("input/vrp_cordeau_01.xml");
Define and add depots, vehicles and their types as follows:
/*
* add vehicles with its depots
* 4 depots with the following coordinates:
* (20,20), (30,40), (50,30), (60,50)
*
* each with 4 vehicles each with a capacity of 80
*/
int nuOfVehicles = 4;
int capacity = 80;
Coordinate firstDepotCoord = Coordinate.newInstance(20, 20);
Coordinate second = Coordinate.newInstance(30, 40);
Coordinate third = Coordinate.newInstance(50, 30);
Coordinate fourth = Coordinate.newInstance(60, 50);
int depotCounter = 1;
for(Coordinate depotCoord : Arrays.asList(firstDepotCoord,second,third,fourth)){
for(int i=0;i<nuOfVehicles;i++){
String typeId = depotCounter + "_type";
VehicleType vehicleType = VehicleTypeImpl.Builder.newInstance(typeId).addCapacityDimension(0,capacity).setCostPerDistance(1.0).build();
String vehicleId = depotCounter + "_" + (i+1) + "_vehicle";
VehicleImpl.Builder vehicleBuilder = VehicleImpl.Builder.newInstance(vehicleId);
vehicleBuilder.setStartLocation(Location.newInstance(depotCoord.getX(),depotCoord.getY())); //defines the location of the vehicle and thus the depot
vehicleBuilder.setType(vehicleType)
VehicleImpl vehicle = vehicleBuilder.build();
vrpBuilder.addVehicle(vehicle);
}
depotCounter++;
}
Note that there is no explicit depot definition. Depots are defined by the location of vehicles.
Set finite fleet-size and build the problem.
/*
* define problem with finite fleet
*/
vrpBuilder.setFleetSize(FleetSize.FINITE);
/*
* build the problem
*/
VehicleRoutingProblem vrp = vrpBuilder.build();
Plot it, to see how it looks like.
Plotter plotter = new Plotter(vrp).plot("output/problem01.png", "p01");
It looks like this:
Define and run an algorithm to solve the problem.
/*
* solve the problem
*/
VehicleRoutingAlgorithm vra = Jsprit.createAlgorithm(vrp);
Collection solutions = vra.searchSolutions();
You can plot it by:
Plotter plotter = new Plotter(vrp,Solutions.bestOf(solutions));
plotter.plot("output/p01_solution.png", "p01");
and print the results to your console by:
SolutionPrinter.print(vrp,Solutions.bestOf(solutions),Print.VERBOSE);
+--------------------------+
| problem |
+---------------+----------+
| indicator | value |
+---------------+----------+
| nJobs | 50 |
| nServices | 50 |
| nShipments | 0 |
| fleetsize | FINITE |
+--------------------------+
+----------------------------------------------------------+
| solution |
+---------------+------------------------------------------+
| indicator | value |
+---------------+------------------------------------------+
| costs | 582.9805315622696 |
| nVehicles | 11 |
+----------------------------------------------------------+
+--------------------------------------------------------------------------------------------------------------------------------+
| detailed solution |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| route | vehicle | activity | job | arrTime | endTime | costs |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 1 | 3_1_vehicle | start | - | undef | 0 | 0 |
| 1 | 3_1_vehicle | service | 9 | 4 | 4 | 4 |
| 1 | 3_1_vehicle | service | 34 | 13 | 13 | 13 |
| 1 | 3_1_vehicle | service | 30 | 19 | 19 | 19 |
| 1 | 3_1_vehicle | service | 39 | 31 | 31 | 31 |
| 1 | 3_1_vehicle | service | 10 | 41 | 41 | 41 |
| 1 | 3_1_vehicle | end | - | 50 | undef | 50 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 2 | 2_2_vehicle | start | - | undef | 0 | 0 |
| 2 | 2_2_vehicle | service | 11 | 12 | 12 | 12 |
| 2 | 2_2_vehicle | service | 32 | 18 | 18 | 18 |
| 2 | 2_2_vehicle | service | 1 | 25 | 25 | 25 |
| 2 | 2_2_vehicle | service | 22 | 32 | 32 | 32 |
| 2 | 2_2_vehicle | service | 28 | 42 | 42 | 42 |
| 2 | 2_2_vehicle | service | 31 | 48 | 48 | 48 |
| 2 | 2_2_vehicle | service | 26 | 58 | 58 | 58 |
| 2 | 2_2_vehicle | end | - | 86 | undef | 86 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 3 | 2_4_vehicle | start | - | undef | 0 | 0 |
| 3 | 2_4_vehicle | service | 46 | 2 | 2 | 2 |
| 3 | 2_4_vehicle | service | 12 | 9 | 9 | 9 |
| 3 | 2_4_vehicle | service | 47 | 15 | 15 | 15 |
| 3 | 2_4_vehicle | end | - | 25 | undef | 25 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 4 | 2_1_vehicle | start | - | undef | 0 | 0 |
| 4 | 2_1_vehicle | service | 23 | 22 | 22 | 22 |
| 4 | 2_1_vehicle | service | 7 | 28 | 28 | 28 |
| 4 | 2_1_vehicle | service | 43 | 40 | 40 | 40 |
| 4 | 2_1_vehicle | service | 24 | 53 | 53 | 53 |
| 4 | 2_1_vehicle | service | 14 | 63 | 63 | 63 |
| 4 | 2_1_vehicle | end | - | 81 | undef | 81 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 5 | 4_2_vehicle | start | - | undef | 0 | 0 |
| 5 | 4_2_vehicle | service | 20 | 9 | 9 | 9 |
| 5 | 4_2_vehicle | service | 3 | 16 | 16 | 16 |
| 5 | 4_2_vehicle | service | 36 | 28 | 28 | 28 |
| 5 | 4_2_vehicle | service | 35 | 35 | 35 | 35 |
| 5 | 4_2_vehicle | end | - | 48 | undef | 48 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 6 | 1_2_vehicle | start | - | undef | 0 | 0 |
| 6 | 1_2_vehicle | service | 44 | 11 | 11 | 11 |
| 6 | 1_2_vehicle | service | 45 | 21 | 21 | 21 |
| 6 | 1_2_vehicle | service | 33 | 28 | 28 | 28 |
| 6 | 1_2_vehicle | service | 15 | 40 | 40 | 40 |
| 6 | 1_2_vehicle | service | 37 | 47 | 47 | 47 |
| 6 | 1_2_vehicle | service | 17 | 52 | 52 | 52 |
| 6 | 1_2_vehicle | end | - | 60 | undef | 60 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 7 | 3_2_vehicle | start | - | undef | 0 | 0 |
| 7 | 3_2_vehicle | service | 49 | 3 | 3 | 3 |
| 7 | 3_2_vehicle | service | 5 | 11 | 11 | 11 |
| 7 | 3_2_vehicle | service | 38 | 18 | 18 | 18 |
| 7 | 3_2_vehicle | end | - | 25 | undef | 25 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 8 | 1_3_vehicle | start | - | undef | 0 | 0 |
| 8 | 1_3_vehicle | service | 25 | 22 | 22 | 22 |
| 8 | 1_3_vehicle | service | 18 | 33 | 33 | 33 |
| 8 | 1_3_vehicle | service | 4 | 41 | 41 | 41 |
| 8 | 1_3_vehicle | end | - | 47 | undef | 47 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 9 | 2_3_vehicle | start | - | undef | 0 | 0 |
| 9 | 2_3_vehicle | service | 6 | 11 | 11 | 11 |
| 9 | 2_3_vehicle | service | 48 | 20 | 20 | 20 |
| 9 | 2_3_vehicle | service | 8 | 30 | 30 | 30 |
| 9 | 2_3_vehicle | service | 27 | 44 | 44 | 44 |
| 9 | 2_3_vehicle | end | - | 52 | undef | 52 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 10 | 4_3_vehicle | start | - | undef | 0 | 0 |
| 10 | 4_3_vehicle | service | 29 | 3 | 3 | 3 |
| 10 | 4_3_vehicle | service | 2 | 12 | 12 | 12 |
| 10 | 4_3_vehicle | service | 16 | 20 | 20 | 20 |
| 10 | 4_3_vehicle | service | 50 | 26 | 26 | 26 |
| 10 | 4_3_vehicle | service | 21 | 34 | 34 | 34 |
| 10 | 4_3_vehicle | end | - | 42 | undef | 42 |
+---------+----------------------+-----------------------+-----------------+-----------------+-----------------+-----------------+
| 11 | 1_4_vehicle | start | - | undef | 0 | 0 |
| 11 | 1_4_vehicle | service | 13 | 16 | 16 | 16 |
| 11 | 1_4_vehicle | service | 41 | 25 | 25 | 25 |
| 11 | 1_4_vehicle | service | 40 | 37 | 37 | 37 |
| 11 | 1_4_vehicle | service | 19 | 48 | 48 | 48 |
| 11 | 1_4_vehicle | service | 42 | 57 | 57 | 57 |
| 11 | 1_4_vehicle | end | - | 67 | undef | 67 |
+--------------------------------------------------------------------------------------------------------------------------------+
You can find the entire code here.