/// <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
NodeEvaluator2[] cost_callbacks = new NodeEvaluator2[number_of_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);
cost_callbacks[vehicle] = manhattan_cost_callback;
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.AllUnperformed;
Console.WriteLine("Search");
Assignment solution = model.SolveWithParameters(search_parameters);
//protect callbacks from the GC
GC.KeepAlive(manhattan_callback);
GC.KeepAlive(demand_callback);
for (int cost_callback_index = 0; cost_callback_index < cost_callbacks.Length; cost_callback_index++)
{
GC.KeepAlive(cost_callbacks[cost_callback_index]);
}
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);
}
}
/// <summary>
/// requires data.SantaIds
/// requires data.Visits
/// requires data.HomeIndex
/// requires data.Unavailable
/// requires data.Start
/// requires data.End
/// </summary>
public static OptimizationResult Solve(RoutingData data, long timeLimitMilliseconds, ITimeWindowStrategy strategy)
{
if (false ||
data.SantaIds == null ||
data.Visits == null ||
data.Unavailable == null ||
data.SantaStartIndex == null ||
data.SantaEndIndex == null
)
{
throw new ArgumentNullException();
}
var model = new RoutingModel(data.Visits.Length, data.SantaIds.Length, data.SantaStartIndex, data.SantaEndIndex);
// setting up dimensions
var maxTime = GetMaxTime(data);
var timeCallback = new TimeEvaluator(data);
model.AddDimension(timeCallback, 0, maxTime, false, DimensionTime);
var lengthCallback = new TimeEvaluator(data);
model.AddDimension(lengthCallback, 0, maxTime, true, DimensionLength);
// set additional cost of longest day
{
var dim = model.GetDimensionOrDie(DimensionLength);
dim.SetGlobalSpanCostCoefficient(data.Cost.CostLongestDayPerHour);
}
// dimensions for breaks
var breakCallbacks = new List <BreakEvaluator>();
var breakDimensions = new List <string>();
for (int santa = 0; santa < data.NumberOfSantas; santa++)
{
var maxBreaks = GetNumberOfBreaks(data, santa);
if (maxBreaks == 0)
{
// no breaks
continue;
}
var evaluator = new BreakEvaluator(data, santa);
var dimension = GetSantaBreakDimension(santa);
model.AddDimension(evaluator, 0, maxBreaks, true, dimension);
breakCallbacks.Add(evaluator);
breakDimensions.Add(dimension);
}
// setting up santas (=vehicles)
var costCallbacks = new NodeEvaluator2[data.NumberOfSantas];
for (int santa = 0; santa < data.NumberOfSantas; santa++)
{
// must be a new instance per santa
NodeEvaluator2 costCallback = data.Input.IsAdditionalSanta(data.SantaIds[santa])
? new CostEvaluator(data, data.Cost.CostWorkPerHour + data.Cost.CostAdditionalSantaPerHour, data.Cost.CostAdditionalSanta)
: new CostEvaluator(data, data.Cost.CostWorkPerHour, 0);
costCallbacks[santa] = costCallback;
model.SetVehicleCost(santa, costCallback);
// limit time per santa
var day = data.GetDayFromSanta(santa);
var start = GetDayStart(data, day);
var end = GetDayEnd(data, day);
model.CumulVar(model.End(santa), DimensionTime).SetRange(start, end);
model.CumulVar(model.Start(santa), DimensionTime).SetRange(start, end);
// avoid visiting breaks of other santas
var breakDimension = GetSantaBreakDimension(santa);
foreach (var dimension in breakDimensions.Except(new[] { breakDimension }))
{
model.CumulVar(model.End(santa), dimension).SetMax(0);
}
}
// setting up visits (=orders)
for (int visit = 0; visit < data.NumberOfVisits; ++visit)
{
var cumulTimeVar = model.CumulVar(visit, DimensionTime);
cumulTimeVar.SetRange(data.OverallStart, data.OverallEnd);
model.AddDisjunction(new[] { visit }, data.Cost.CostNotVisitedVisit);
// add desired / unavailable according to strategy
var timeDimension = model.GetDimensionOrDie(DimensionTime);
strategy.AddConstraints(data, model, cumulTimeVar, timeDimension, visit);
}
// Solving
var searchParameters = RoutingModel.DefaultSearchParameters();
searchParameters.FirstSolutionStrategy = FirstSolutionStrategy.Types.Value.Automatic; // maybe try AllUnperformed or PathCheapestArc
searchParameters.LocalSearchMetaheuristic = LocalSearchMetaheuristic.Types.Value.GuidedLocalSearch;
searchParameters.TimeLimitMs = timeLimitMilliseconds;
var solution = model.SolveWithParameters(searchParameters);
// protect callbacks from the GC
GC.KeepAlive(timeCallback);
GC.KeepAlive(lengthCallback);
foreach (var costCallback in costCallbacks)
{
GC.KeepAlive(costCallback);
}
foreach (var breakCallback in breakCallbacks)
{
GC.KeepAlive(breakCallback);
}
Debug.WriteLine($"obj={solution?.ObjectiveValue()}");
return(CreateResult(data, model, solution));
}