/// <summary>
/// Switches the given directed id to the best turn given the before and after directed id's.
/// </summary>
public static bool SwitchToBestTurn(int directedId, int beforeDirectedId, int afterDirectedId, float[][] weights, float[] turnPenalties,
out int betterDirectedId, out bool departureIdSwitched, out bool arrivalIdSwitched, out float delta)
{
int arrivalId, departureId, turn, id, beforeDepartureOffset, afterArrivalOffset, temp;
DirectedHelper.ExtractOffset(DirectedHelper.ExtractTurn(beforeDirectedId), out temp, out beforeDepartureOffset);
DirectedHelper.ExtractOffset(DirectedHelper.ExtractTurn(afterDirectedId), out afterArrivalOffset, out temp);
DirectedHelper.ExtractAll(directedId, out arrivalId, out departureId, out id, out turn);
var bestWeight = float.MaxValue;
var bestDirectedId = -1;
var previousWeight = float.MaxValue;
departureIdSwitched = false;
arrivalIdSwitched = false;
for (var newBeforeDepartureOffset = 0; newBeforeDepartureOffset < 2; newBeforeDepartureOffset++)
{
for (var newAfterArrivalOffset = 0; newAfterArrivalOffset < 2; newAfterArrivalOffset++)
{
for (var i = 0; i < 4; i++)
{
var newDirectedId = DirectedHelper.BuildDirectedId(id, i);
int localTurn;
DirectedHelper.ExtractAll(newDirectedId, out arrivalId, out departureId, out id, out localTurn);
var newBeforeDirectedId = DirectedHelper.UpdateDepartureOffset(beforeDirectedId, newBeforeDepartureOffset);
var newAfterDirectedId = DirectedHelper.UpdateArrivalOffset(afterDirectedId, newAfterArrivalOffset);
var newBeforeDepartureId = DirectedHelper.ExtractDepartureId(newBeforeDirectedId);
var newAfterArrivalId = DirectedHelper.ExtractArrivalId(newAfterDirectedId);
var newBeforeTurn = DirectedHelper.ExtractTurn(newBeforeDirectedId);
var newAfterTurn = DirectedHelper.ExtractTurn(newAfterDirectedId);
var newWeight = turnPenalties[localTurn];
newWeight += weights[newBeforeDepartureId][arrivalId];
newWeight += weights[departureId][newAfterArrivalId];
newWeight += turnPenalties[newBeforeTurn];
newWeight += turnPenalties[newAfterTurn];
if (i == turn && newBeforeDepartureOffset == beforeDepartureOffset &&
newAfterArrivalOffset == afterArrivalOffset)
{
previousWeight = newWeight;
}
if (bestWeight > newWeight)
{
bestWeight = newWeight;
bestDirectedId = newDirectedId;
departureIdSwitched = newBeforeDepartureOffset != beforeDepartureOffset;
arrivalIdSwitched = newAfterArrivalOffset != afterArrivalOffset;
}
}
}
}
delta = previousWeight - bestWeight;
betterDirectedId = bestDirectedId;
return(betterDirectedId != directedId);
}
/// <summary>
/// Calculates the weights between the two directed id's without the turn weights.
/// </summary>
public static float WeightWithoutTurns(this float[][] weights, int directed1, int directed2)
{
int arrivalId1, departureId1, id1, turn1, arrivalId2, departureId2, id2, turn2;
DirectedHelper.ExtractAll(directed1, out arrivalId1, out departureId1, out id1, out turn1);
DirectedHelper.ExtractAll(directed2, out arrivalId2, out departureId2, out id2, out turn2);
return(weights[departureId1][arrivalId2]);
}
/// <summary>
/// Switches the arrival offset.
/// </summary>
public static int SwitchArrivalOffset(int directedId)
{
int turn;
var id = DirectedHelper.ExtractId(directedId, out turn);
int arrivalOffset, oldDepartureOffset;
DirectedHelper.ExtractOffset(turn, out arrivalOffset, out oldDepartureOffset);
return(DirectedHelper.BuildDirectedId(id, DirectedHelper.BuildTurn(1 - arrivalOffset, oldDepartureOffset)));
}
/// <summary>
/// Calculates the weight of the given tour.
/// </summary>
public static float Weight(this Tour tour, float[][] weights, float[] turnPenalties)
{
var weight = 0f;
var previousFrom = int.MaxValue;
var firstTo = int.MaxValue;
var lastTurn = int.MaxValue;
foreach (var directedId in tour)
{
// extract turns and stuff from directed id.
int arrivalId, departureId, id, turn;
DirectedHelper.ExtractAll(directedId, out arrivalId, out departureId, out id, out turn);
// add the weight from the previous customer to the current one.
if (previousFrom != int.MaxValue)
{
weight = weight + weights[previousFrom][arrivalId];
}
else
{
firstTo = arrivalId;
}
// add turn penalty.
if ((tour.First != directedId &&
tour.Last != directedId) ||
tour.Last == tour.First)
{ // never count turn @ first customer.
// don't count turn @ last customer if it's different from first.
weight += turnPenalties[turn];
}
previousFrom = departureId;
lastTurn = turn;
}
// remove the last turn penalty if it's an open non-fixed tour.
if (tour.Last == null)
{
weight -= turnPenalties[lastTurn];
}
// add the weight between last and first.
if (previousFrom != int.MaxValue &&
tour.First == tour.Last)
{
weight = weight + weights[previousFrom][firstTo];
}
return(weight);
}
/// <summary>
/// Shifts the directed customer aft er the given directed before with the best possible turns.
/// </summary>
public static float ShiftAfterBestTurns(this Tour tour, float[][] weights, float[] penalties, int directedCustomer, int directedBefore)
{
var customer = DirectedHelper.ExtractId(directedCustomer);
var directedAfter = tour.GetNeigbour(directedCustomer);
if (directedAfter == Constants.NOT_SET)
{ // TODO: figure out if this happens and if so how to calculate turns.
return(0);
}
// insert directed customer.
tour.ShiftAfter(directedCustomer, directedBefore);
// calculate best shift-after.
int departureOffset1, arrivalOffset3, turn2;
var cost = CheapestInsertion.CheapestInsertionDirectedHelper.CalculateCheapestInsert(weights, penalties, directedBefore, customer, directedAfter,
!tour.IsFirst(directedBefore), !tour.IsLast(directedAfter), out departureOffset1, out arrivalOffset3, out turn2);
var newDirectedBefore = DirectedHelper.UpdateDepartureOffset(directedBefore, departureOffset1);
var newDirectedAfter = DirectedHelper.UpdateArrivalOffset(directedAfter, arrivalOffset3);
var newDirectedCustomer = DirectedHelper.BuildDirectedId(customer, turn2);
if (directedBefore != newDirectedBefore)
{
tour.Replace(directedBefore, newDirectedBefore);
}
if (directedCustomer != newDirectedCustomer)
{
tour.Replace(directedCustomer, newDirectedCustomer);
}
if (directedAfter != newDirectedAfter)
{
tour.Replace(directedAfter, newDirectedAfter);
}
return(cost);
}
