private void IncludeNewPoints(List<int> tour, List<int> visitablePoints,
DistanceMatrix distances, double pointVisitingCosts, double maxLength, DoubleArray scores,
ref double tourLength, ref double tourScore, ref int evaluations, ref bool solutionChanged) {
for (int tourPosition = 1; tourPosition < tour.Count; tourPosition++) {
// If an optimization has been done, start from the beginning
if (solutionChanged) break;
for (int i = 0; i < visitablePoints.Count; i++) {
// If an optimization has been done, start from the beginning
if (solutionChanged) break;
evaluations++;
double detour = distances.CalculateInsertionCosts(tour, tourPosition, visitablePoints[i], pointVisitingCosts);
// Determine if including the point does not violate any constraint
if (tourLength + detour <= maxLength) {
// Insert the new point at this position
tour.Insert(tourPosition, visitablePoints[i]);
// Update the overall tour tourLength and score
tourLength += detour;
tourScore += scores[visitablePoints[i]];
// Re-run this optimization
solutionChanged = true;
}
}
}
}
private void ReplacePoints(List<int> tour, List<int> visitablePoints,
DistanceMatrix distances, double maxLength, DoubleArray scores,
ref double tourLength, ref double tourScore, ref int evaluations, ref bool solutionChanged) {
for (int tourPosition = 1; tourPosition < tour.Count - 1; tourPosition++) {
// If an optimization has been done, start from the beginning
if (solutionChanged) break;
for (int i = 0; i < visitablePoints.Count; i++) {
// If an optimization has been done, start from the beginning
if (solutionChanged) break;
evaluations++;
double detour = distances.CalculateReplacementCosts(tour, tourPosition, visitablePoints[i]);
double oldPointScore = scores[tour[tourPosition]];
double newPointScore = scores[visitablePoints[i]];
if ((tourLength + detour <= maxLength) && (newPointScore > oldPointScore)) {
// Replace the old point by the new one
tour[tourPosition] = visitablePoints[i];
// Update the overall tour tourLength
tourLength += detour;
// Update the scores achieved by visiting this point
tourScore += newPointScore - oldPointScore;
// Re-run this optimization
solutionChanged = true;
}
}
}
}
public static OrienteeringEvaluationResult Apply(IntegerVector solution, DoubleArray scores,
DistanceMatrix distances, double maximumDistance, double pointVisitingCosts, double distancePenaltyFactor) {
double score = solution.Sum(t => scores[t]);
double distance = distances.CalculateTourLength(solution.ToList(), pointVisitingCosts);
double distanceViolation = distance - maximumDistance;
double penalty = 0.0;
penalty += distanceViolation > 0 ? distanceViolation * distancePenaltyFactor : 0;
double quality = score - penalty;
return new OrienteeringEvaluationResult {
Quality = new DoubleValue(quality),
Penalty = new DoubleValue(penalty),
Distance = new DoubleValue(distance)
};
}
private void ShortenPath(List<int> tour, DistanceMatrix distances, int maxBlockLength, bool useMaxBlockLength, ref double tourLength, ref int evaluations) {
bool solutionChanged;
int pathSize = tour.Count;
maxBlockLength = (useMaxBlockLength && (pathSize > maxBlockLength + 1)) ? maxBlockLength : (pathSize - 2);
// Perform a 2-opt
do {
solutionChanged = false;
for (int blockLength = 2; blockLength < maxBlockLength; blockLength++) {
// If an optimization has been done, start from the beginning
if (solutionChanged) break;
for (int position = 1; position < (pathSize - blockLength); position++) {
// If an optimization has been done, start from the beginning
if (solutionChanged) break;
evaluations++;
double newLength = tourLength;
// Recalculate length of whole swapped part, in case distances are not symmetric
for (int index = position - 1; index < position + blockLength; index++) newLength -= distances[tour[index], tour[index + 1]];
for (int index = position + blockLength - 1; index > position; index--) newLength += distances[tour[index], tour[index - 1]];
newLength += distances[tour[position - 1], tour[position + blockLength - 1]];
newLength += distances[tour[position], tour[position + blockLength]];
if (newLength < tourLength - 0.00001) {
// Avoid cycling caused by precision
var reversePart = tour.GetRange(position, blockLength).AsEnumerable().Reverse();
tour.RemoveRange(position, blockLength);
tour.InsertRange(position, reversePart);
tourLength = newLength;
// Re-run the optimization
solutionChanged = true;
}
}
}
} while (solutionChanged);
}
public OrienteeringEvaluationResult Evaluate(IntegerVector solution, DoubleArray scores,
DistanceMatrix distances, double maximumDistance, double pointVisitingCosts) {
return Apply(solution, scores, distances, maximumDistance, pointVisitingCosts,
((IValueParameter<DoubleValue>)DistancePenaltyFactorParameter).Value.Value);
}
private void CleanupTour(List<int> actualTour, DistanceMatrix distances, double maxDistance, double pointVisitingCosts) {
// Sort the points on the tour according to their costs savings when removed
var distanceSavings = (
from removePosition in Enumerable.Range(1, actualTour.Count - 2)
let saving = distances.CalculateRemovementSaving(actualTour, removePosition, pointVisitingCosts)
orderby saving descending
select new SavingInfo { Index = removePosition, Saving = saving }
).ToList();
double tourLength = distances.CalculateTourLength(actualTour, pointVisitingCosts);
// As long as the created path is infeasible, remove elements
while (tourLength > maxDistance) {
// Remove the point that frees the largest distance
// Note, distance savings are not updated after removal
tourLength -= distances.CalculateRemovementSaving(actualTour, distanceSavings[0].Index, pointVisitingCosts);
actualTour.RemoveAt(distanceSavings[0].Index);
// Shift indices due to removal of a point in the tour
for (int i = 1; i < distanceSavings.Count; i++) {
if (distanceSavings[i].Index > distanceSavings[0].Index) {
distanceSavings[i].Index--;
}
}
distanceSavings.RemoveAt(0);
}
}
private DistanceMatrix(DistanceMatrix original, Cloner cloner) {
throw new NotSupportedException("Distance matrices cannot be cloned.");
}
private DistanceMatrix(DistanceMatrix original, Cloner cloner)
{
throw new NotSupportedException("Distance matrices cannot be cloned.");
}
public OrienteeringEvaluationResult Evaluate(IntegerVector solution, DoubleArray scores,
DistanceMatrix distances, double maximumDistance, double pointVisitingCosts)
{
return(Apply(solution, scores, distances, maximumDistance, pointVisitingCosts,
((IValueParameter <DoubleValue>)DistancePenaltyFactorParameter).Value.Value));
}
