void Solve(int limit)
{
// Declares the optimization model.
LSModel model = localsolver.GetModel();
trucksUsed = new LSExpression[nbTrucks];
customersSequences = new LSExpression[nbTrucks];
routeDistances = new LSExpression[nbTrucks];
// Sequence of customers visited by each truck.
for (int k = 0; k < nbTrucks; k++)
{
customersSequences[k] = model.List(nbCustomers);
}
// All customers must be visited by the trucks
model.Constraint(model.Partition(customersSequences));
// Create demands and distances as arrays to be able to access it with an "at" operator
LSExpression demandsArray = model.Array(demands);
LSExpression distanceWarehouseArray = model.Array(distanceWarehouses);
LSExpression distanceArray = model.Array(distanceMatrix);
for (int k = 0; k < nbTrucks; k++)
{
LSExpression sequence = customersSequences[k];
LSExpression c = model.Count(sequence);
// A truck is used if it visits at least one customer
trucksUsed[k] = c > 0;
// The quantity needed in each route must not exceed the truck capacity
LSExpression demandSelector = model.Function(i => demandsArray[sequence[i]]);
LSExpression routeQuantity = model.Sum(model.Range(0, c), demandSelector);
model.Constraint(routeQuantity <= truckCapacity);
// Distance travelled by truck k
LSExpression distSelector = model.Function(i => distanceArray[sequence[i - 1], sequence[i]]);
routeDistances[k] = model.Sum(model.Range(1, c), distSelector)
+ model.If(c > 0, distanceWarehouseArray[sequence[0]] + distanceWarehouseArray[sequence[c - 1]], 0);
}
nbTrucksUsed = model.Sum(trucksUsed);
totalDistance = model.Sum(routeDistances);
// Objective: minimize the number of trucks used, then minimize the distance traveled
model.Minimize(nbTrucksUsed);
model.Minimize(totalDistance);
model.Close();
// Parameterizes the solver.
LSPhase phase = localsolver.CreatePhase();
phase.SetTimeLimit(limit);
localsolver.Solve();
}
/// <summary>
/// Sets the SantaVisitStartingTimes variable
/// </summary>
/// <param name="day"></param>
/// <param name="santa"></param>
public void SetVisitStartingTimes(int day, int santa)
{
var s = GetSantaId(day, santa);
var sequence = solverVariables.VisitSequences[s];
var c = model.Count(sequence);
var visitStartingTimeSelector = model.Function((i, prev) =>
model.If(i == 0,
solverVariables.OptimizationInput.Days[day].from + solverVariables.SantaWaitBeforeStart[s] + solverVariables.DistanceFromHomeArray[sequence[i]],
prev + solverVariables.VisitDurationArray[sequence[i - 1]] + solverVariables.DistanceArray[sequence[i - 1], sequence[i]] + solverVariables.SantaWaitBetweenVisitArray[s][sequence[i]]
)
);
var visitStartingTime = model.Array(model.Range(0, c), visitStartingTimeSelector);
solverVariables.SantaVisitStartingTimes[s] = visitStartingTime;
}
public SolverVariables(LSModel model, int numberOfRoutes, List <Visit> visits, int[,] routeCosts, OptimizationInput optimizationInput, int numberOfFakeSantas)
{
Model = model;
Visits = visits;
NumberOfRoutes = numberOfRoutes;
OptimizationInput = optimizationInput;
NumberOfFakeSantas = numberOfFakeSantas;
NumberOfSantas = optimizationInput.Santas.Length;
SantaUsed = new LSExpression[numberOfRoutes];
VisitSequences = new LSExpression[numberOfRoutes + 1];
SantaWalkingTime = new LSExpression[numberOfRoutes];
SantaRouteTime = new LSExpression[numberOfRoutes];
SantaVisitDurations = new LSExpression[numberOfRoutes];
SantaDesiredDuration = new LSExpression[numberOfRoutes];
SantaUnavailableDuration = new LSExpression[numberOfRoutes];
SantaVisitStartingTimes = new LSExpression[numberOfRoutes];
SantaOvertime = new LSExpression[numberOfRoutes];
SantaWaitBeforeStart = new LSExpression[numberOfRoutes];
SantaWaitBetweenVisit = new LSExpression[numberOfRoutes][];
SantaWaitBetweenVisitArray = new LSExpression[numberOfRoutes];
int numberOfVisits = Visits.Count;
var longestDay = OptimizationInput.Days.Max(d => d.to - d.from);
for (var k = 0; k < numberOfRoutes; k++)
{
VisitSequences[k] = Model.List(numberOfVisits);
SantaOvertime[k] = Model.Int(0, int.MaxValue);
SantaWaitBeforeStart[k] = Model.Int(0, longestDay);
SantaWaitBetweenVisit[k] = new LSExpression[numberOfVisits];
for (var i = 0; i < SantaWaitBetweenVisit[k].Length; i++)
{
SantaWaitBetweenVisit[k][i] = Model.Int(0, longestDay);
}
SantaWaitBetweenVisitArray[k] = Model.Array(SantaWaitBetweenVisit[k]);
}
// overflow for unused santa breaks
VisitSequences[numberOfRoutes] = model.List(numberOfVisits);
DistanceArray = model.Array(RouteCostJagged(Visits, routeCosts));
DistanceFromHomeArray = model.Array(Visits.Select(v => v.WayCostFromHome).ToArray());
DistanceToHomeArray = model.Array(Visits.Select(v => v.WayCostToHome).ToArray());
VisitDurationArray = model.Array(Visits.Select(v => v.Duration).ToArray());
// desired
var visitsOnlyDesired = visits
.Select(v =>
// fake arr
v.Desired.Length == 0
? new[] { new[] { -1, -1 } }
: v.Desired.Select(d => new[] { d.from, d.to }).ToArray()
)
.ToArray();
VisitDesiredArray = model.Array(visitsOnlyDesired);
VisitDesiredCountArray = model.Array(visits.Select(v => v.Desired.Length).ToArray());
// unavailable
var visitsOnlyUnavailable = visits
.Select(v =>
// fake arr
v.Unavailable.Length == 0
? new[] { new[] { -1, -1 } }
: v.Unavailable.Select(d => new[] { d.from, d.to }).ToArray()
)
.ToArray();
VisitUnavailableArray = model.Array(visitsOnlyUnavailable);
VisitUnavailableCountArray = model.Array(visits.Select(v => v.Unavailable.Length).ToArray());
}
