public int PrintStatus(RoutingModel routing)
{
switch (routing.GetStatus())
{
case 0:
Console.WriteLine("Problem is not solved yet.");
return(0);
case 1:
Console.WriteLine("Problem is solved");
return(1);
case 2:
Console.WriteLine("No solution found to the problem.");
return(2);
case 3:
Console.WriteLine("Time limit reached before finding a solution.");
return(3);
case 4:
Console.WriteLine("Model, model parameters, or flags are not valid.");
return(4);
default:
return(-1);
}
}
static void Solve(int size, int forbidden, int seed)
{
RoutingIndexManager manager = new RoutingIndexManager(size, 1, 0);
RoutingModel routing = new RoutingModel(manager);
// Setting the cost function.
// Put a permanent callback to the distance accessor here. The callback
// has the following signature: ResultCallback2<int64_t, int64_t, int64_t>.
// The two arguments are the from and to node inidices.
RandomManhattan distances = new RandomManhattan(manager, size, seed);
routing.SetArcCostEvaluatorOfAllVehicles(routing.RegisterTransitCallback(distances.Call));
// 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(routing.RegisterUnaryTransitCallback((long index) =>
{ return(1); }),
size + 1, size + 1, true, "dummy");
// Solve, returns a solution if any (owned by RoutingModel).
RoutingSearchParameters search_parameters =
operations_research_constraint_solver.DefaultRoutingSearchParameters();
// Setting first solution heuristic (cheapest addition).
search_parameters.FirstSolutionStrategy = FirstSolutionStrategy.Types.Value.PathCheapestArc;
Assignment solution = routing.SolveWithParameters(search_parameters);
Console.WriteLine("Status = {0}", routing.GetStatus());
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");
}
}
public string GetSolverStatus()
{
string status = "";
int solverStatus = RoutingModel.GetStatus();
switch (solverStatus)
{
case 0: status = "ROUTING_NOT_SOLVED"; //Problem not solved yet
break;
case 1: status = "ROUTING_SUCCESS"; //Problem solved successfully.
break;
case 2: status = "ROUTING_FAIL"; //No solution found to the problem
break;
case 3: status = "ROUTING_FAIL_TIMEOUT"; //Time limit reached before finding the solution
break;
case 4: status = "ROUTING_INVALID"; //Model, parameter or flags are not valid
break;
}
return(status);
}
