I’ve got my first custom minimal example with 3-4 nodes running, it’s based on the “CostMatrixExample”. I have put normal paths at a cost of 5, a few “unpreferred” paths at a cost of 400 and a path with a cost of 2*1 that is supposed to be a “highway” and much faster than the 400 one.
My problem is that for some reason jsprit thinks the path with 400 (resulting in a cost of 410) is better than taking the same path back and it’s entirely ignoring the fastest node which would give a cost of just 22.
I’m sure I’m doing something wrong here but I cannot pin down the issue at all. I’ve changed almost nothing except for adding coordinates and cost. If you removed the fourth “quick” node it also prefers the 400 route instead of just driving the same path back. The Matrix is symmetrical so I’m unable to comprehend why this is happening.
Please don’t mind the tt function, it’s just because I quickly wanted to map the example strings to coordinates.
Thank you for your support.
public class CartMinimal {
static boolean HIGHWAY_EXISTS = false; //true adds node 3 that has the quickest link between 0 and 2
static double NA = 400.0; //arbitrary number to prevent usage of this road, has no effect :(
public static void main(String[] args) {
Examples.createOutputFolder();
Location l0 = Location.Builder.newInstance().setIndex(0).setCoordinate(Coordinate.newInstance(0.0, 0.0)).build();
Location l1 = Location.Builder.newInstance().setIndex(0).setCoordinate(Coordinate.newInstance(10, 0.0)).build();
Location l2 = Location.Builder.newInstance().setIndex(0).setCoordinate(Coordinate.newInstance(10, -3.0)).build();
VehicleType type = VehicleTypeImpl.Builder.newInstance("type").addCapacityDimension(0, 5).setCostPerDistance(1).build();
VehicleImpl vehicle = VehicleImpl.Builder.newInstance("vehicle")
.setStartLocation(l0).setType(type).build();
Service s1 = Service.Builder.newInstance("1").addSizeDimension(0, 1).setLocation(l1).build();
Service s2 = Service.Builder.newInstance("2").addSizeDimension(0, 1).setLocation(l2).build();
VehicleRoutingTransportCostsMatrix.Builder costMatrixBuilder = VehicleRoutingTransportCostsMatrix.Builder.newInstance(true);
costMatrixBuilder.addTransportDistance(tt("0"), tt("1"), 5.0);
costMatrixBuilder.addTransportDistance(tt("0"), tt("2"), NA);
costMatrixBuilder.addTransportDistance(tt("1"), tt("2"), 5.0);
if(HIGHWAY_EXISTS) { //fastest between 0 and 2
costMatrixBuilder.addTransportDistance(tt("0"), tt("3"), 1.0);
costMatrixBuilder.addTransportDistance(tt("1"), tt("3"), NA);
costMatrixBuilder.addTransportDistance(tt("2"), tt("3"), 1.0);
}
costMatrixBuilder.addTransportTime(tt("0"), tt("1"), 5.0);
costMatrixBuilder.addTransportTime(tt("0"), tt("2"), NA);
costMatrixBuilder.addTransportTime(tt("1"), tt("2"), 5.0);
if(HIGHWAY_EXISTS) {
costMatrixBuilder.addTransportTime(tt("0"), tt("3"), 1.0);
costMatrixBuilder.addTransportTime(tt("1"), tt("3"), NA);
costMatrixBuilder.addTransportTime(tt("2"), tt("3"), 1.0);
}
VehicleRoutingTransportCosts costMatrix = costMatrixBuilder.build();
VehicleRoutingProblem vrp = VehicleRoutingProblem.Builder.newInstance().setFleetSize(FleetSize.FINITE).setRoutingCost(costMatrix)
.addVehicle(vehicle).addJob(s1).addJob(s2).build();
VehicleRoutingAlgorithm vra = Jsprit.createAlgorithm(vrp);
Collection<VehicleRoutingProblemSolution> solutions = vra.searchSolutions();
SolutionPrinter.print(Solutions.bestOf(solutions));
new Plotter(vrp, Solutions.bestOf(solutions)).plot("output/yo.png", "po");
System.out.println(solutions);
new GraphStreamViewer(vrp, Solutions.bestOf(solutions)).setRenderDelay(300).display();
}
public static String tt(String id) {
String newString = "[x=0.9][y=0.9]"; //default value
switch(id) {
case "0":
newString = "[x=0.0][y=0.0]";
break;
case "1":
newString = "[x=10.0][y=0.0]";
break;
case "2":
newString = "[x=10.0][y=-3.0]";
break;
case "3": //fastest edge between 0 and 2
newString = "[x=5.0][y=-8.0]";
break;
default:
System.out.println("WARNING, FALLING TO DEFAULT");
System.out.println(id);
}
return newString;
}
}