static void Solve(int size, int forbidden, int seed)
{
RoutingModel routing = new RoutingModel(size, 1);
// Setting the cost function.
// Put a permanent callback to the distance accessor here. The callback
// has the following signature: ResultCallback2<int64, int64, int64>.
// The two arguments are the from and to node inidices.
RandomManhattan distances = new RandomManhattan(size, seed);
routing.SetCost(distances);
// Forbid node connections (randomly).
Random randomizer = new Random();
long forbidden_connections = 0;
while (forbidden_connections < forbidden) {
long from = randomizer.Next(size - 1);
long to = randomizer.Next(size - 1) + 1;
if (routing.NextVar(from).Contains(to)) {
Console.WriteLine("Forbidding connection {0} -> {1}", from, to);
routing.NextVar(from).RemoveValue(to);
++forbidden_connections;
}
}
// Add dummy dimension to test API.
routing.AddDimension(new ConstantCallback(),
size + 1,
size + 1,
true,
"dummy");
// Solve, returns a solution if any (owned by RoutingModel).
RoutingSearchParameters search_parameters =
RoutingModel.DefaultSearchParameters();
// Setting first solution heuristic (cheapest addition).
search_parameters.FirstSolutionStrategy =
FirstSolutionStrategy.Types.Value.PathCheapestArc;
Assignment solution = routing.SolveWithParameters(search_parameters);
if (solution != null) {
// Solution cost.
Console.WriteLine("Cost = {0}", solution.ObjectiveValue());
// Inspect solution.
// Only one route here; otherwise iterate from 0 to routing.vehicles() - 1
int route_number = 0;
for (long node = routing.Start(route_number);
!routing.IsEnd(node);
node = solution.Value(routing.NextVar(node))) {
Console.Write("{0} -> ", node);
}
Console.WriteLine("0");
}
}
/// <summary>
/// Solves the current routing problem.
/// </summary>
private void Solve(int number_of_orders, int number_of_vehicles) {
Console.WriteLine("Creating model with " + number_of_orders +
" orders and " + number_of_vehicles + " vehicles.");
// Finalizing model
int number_of_locations = locations_.Length;
RoutingModel model =
new RoutingModel(number_of_locations, number_of_vehicles,
vehicle_starts_, vehicle_ends_);
// Setting up dimensions
const int big_number = 100000;
NodeEvaluator2 manhattan_callback = new Manhattan(locations_, 1);
model.AddDimension(
manhattan_callback, big_number, big_number, false, "time");
NodeEvaluator2 demand_callback = new Demand(order_demands_);
model.AddDimension(demand_callback, 0, vehicle_capacity_, true, "capacity");
// Setting up vehicles
for (int vehicle = 0; vehicle < number_of_vehicles; ++vehicle) {
int cost_coefficient = vehicle_cost_coefficients_[vehicle];
NodeEvaluator2 manhattan_cost_callback =
new Manhattan(locations_, cost_coefficient);
model.SetVehicleCost(vehicle, manhattan_cost_callback);
model.CumulVar(model.End(vehicle), "time").SetMax(
vehicle_end_time_[vehicle]);
}
// Setting up orders
for (int order = 0; order < number_of_orders; ++order) {
model.CumulVar(order, "time").SetRange(order_time_windows_[order].start_,
order_time_windows_[order].end_);
int[] orders = {order};
model.AddDisjunction(orders, order_penalties_[order]);
}
// Solving
RoutingSearchParameters search_parameters =
RoutingModel.DefaultSearchParameters();
search_parameters.FirstSolutionStrategy =
FirstSolutionStrategy.Types.Value.ALL_UNPERFORMED;
Console.WriteLine("Search");
Assignment solution = model.SolveWithParameters(search_parameters);
if (solution != null) {
String output = "Total cost: " + solution.ObjectiveValue() + "\n";
// Dropped orders
String dropped = "";
for (int order = 0; order < number_of_orders; ++order) {
if (solution.Value(model.NextVar(order)) == order) {
dropped += " " + order;
}
}
if (dropped.Length > 0) {
output += "Dropped orders:" + dropped + "\n";
}
// Routes
for (int vehicle = 0; vehicle < number_of_vehicles; ++vehicle) {
String route = "Vehicle " + vehicle + ": ";
long order = model.Start(vehicle);
if (model.IsEnd(solution.Value(model.NextVar(order)))) {
route += "Empty";
} else {
for (;
!model.IsEnd(order);
order = solution.Value(model.NextVar(order))) {
IntVar local_load = model.CumulVar(order, "capacity");
IntVar local_time = model.CumulVar(order, "time");
route += order + " Load(" + solution.Value(local_load) + ") " +
"Time(" + solution.Min(local_time) + ", " +
solution.Max(local_time) + ") -> ";
}
IntVar load = model.CumulVar(order, "capacity");
IntVar time = model.CumulVar(order, "time");
route += order + " Load(" + solution.Value(load) + ") " +
"Time(" + solution.Min(time) + ", " + solution.Max(time) + ")";
}
output += route + "\n";
}
Console.WriteLine(output);
}
}