Load distribution

jsprit
1

Hello,

We are currently using jsprit for route planning and optimisation, time and skill constraint checks are applied, but we are unable to figure out solution for following problem -

Consider we have 2 vehicles with capacity as below -
vehicle 1 -> total capacity - 5, weight capacity - 1000
vehicle 2 -> total capacity - 5, weight capacity - 800

And 4 services as below
service 1 -> weight - 900
service 2 -> weight - 400
service 3 -> weight - 200
service 4 -> weight - 200

With time window of 6 hours where in all services can be served if service 1 is allocated to vehicle 1 and remaining 3 services(service 2,3,4) are allocated to vehicle 2. But in this case, algo assigns service 2,3,4 to vehicle 1 leaving service 1 unassigned as vehicle 2 doesn’t have the load capacity.

I tried adding load contraints as below, but it didn’t work
StateManager stateManager = new StateManager(problem); stateManager.updateSkillStates(); stateManager.updateTimeWindowStates(); stateManager.updateLoadStates(); ConstraintManager constraintManager = new ConstraintManager(problem, stateManager); constraintManager.addSkillsConstraint(); constraintManager.addTimeWindowConstraint(); constraintManager.addLoadConstraint();

Please suggest.

2

I cannot reproduce this with Jsprit.createAlgorithm.... Would you mind to write a unit/integration test illustrating this and send a pull request?

3

Hi Stefan,

Please find the test illustrating this example, i have hardcoded the values for easy understanding.

Thanks

4

Hi @koradeprashant,

Try Jsprit algorithm:

Jsprit.Builder algoBuilder = Jsprit.Builder.newInstance(problem);

and

VehicleRoutingAlgorithm algorithm = algoBuilder.buildAlgorithm();

It will return expected result for your illustrative example.

Best regards,
He

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5

Thanks @jie31best, your solution was working fine. However, we were also able to solve this by increasing the cost multiplier in objective function as below:

return new SolutionCostCalculator() { @Override public double getCosts(VehicleRoutingProblemSolution solution) { double c = 0.0; for (VehicleRoute r : solution.getRoutes()) { c += stateManager.getRouteState(r, InternalStates.COSTS, Double.class); c += getFixedCosts(r.getVehicle()); } c += solution.getUnassignedJobs().size() * c * 1000; return c; } private double getFixedCosts(Vehicle vehicle) { if (vehicle == null) return 0.0; if (vehicle.getType() == null) return 0.0; return vehicle.getType().getVehicleCostParams().fix; } };

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