/// <summary>
/// Tests enumeration all edges.
/// </summary>
protected void DoTestEnumeratePairs()
{
// create a new empty route.
IRoute route = this.BuildRoute(0, true);
// do the enumerable.
List <Edge> edges = new List <Edge>(route.Edges());
Assert.AreEqual(0, edges.Count);
if (route != null)
{ // this part needs testing!
Assert.AreEqual(1, route.Count);
Assert.AreEqual(false, route.IsEmpty);
Assert.AreEqual(true, route.IsRound);
for (int customer = 1; customer < 100; customer++)
{
route.InsertAfter(customer - 1, customer);
//route.InsertAfterAndRemove(customer - 1, customer, -1);
edges = new List <Edge>(route.Edges());
Assert.AreEqual(customer + 1, edges.Count);
for (int edge_from = 0; edge_from < customer; edge_from++)
{
Assert.AreEqual(edges[edge_from].From, edge_from);
Assert.AreEqual(edges[edge_from].To, edge_from + 1);
}
Assert.AreEqual(edges[edges.Count - 1].From, edges.Count - 1);
Assert.AreEqual(edges[edges.Count - 1].To, 0);
}
}
}
/// <summary>
/// Calculates the shortest route along all given points starting and ending at the given points.
/// </summary>
/// <param name="vehicle">The vehicle type.</param>
/// <param name="points">The points to travel along.</param>
/// <param name="first">The index of the point to start from.</param>
/// <param name="isRound">Return back to the first point or not.</param>
/// <returns></returns>
public Route CalculateTSP(Vehicle vehicle, RouterPoint[] points, int first, bool isRound)
{
// calculate the weights.
double[][] weights = this.CalculateManyToManyWeight(vehicle, points);
// build the points array.
var locations = new GeoCoordinate[points.Length];
for (int idx = 0; idx < points.Length; idx++)
{
locations[idx] = points[idx].Location;
}
// calculates the TSP solution.
IRoute tspSolution = _routerTSP.CalculateTSP(weights, locations, first, isRound);
// calculate weight
double weight = 0;
foreach (Edge edge in tspSolution.Edges())
{
weight = weight + weights[edge.From][edge.To];
}
// concatenate the route(s).
return(this.BuildRoute(vehicle, points, tspSolution, weight));
}
/// <summary>
/// Calculates the time of one route.
/// </summary>
/// <param name="route"></param>
/// <returns></returns>
public double Time(IRoute route)
{
double time = 0;
foreach (Edge edge in route.Edges())
{
time = time + this.WeightMatrix[edge.From][edge.To];
}
return(this.Time(time, route.Count));
}
/// <summary>
/// Calculates the time of one route.
/// </summary>
/// <param name="route"></param>
/// <returns></returns>
public double Time(IRoute route)
{
double time = 0;
//Edge? first = null;
//Edge? last = null;
foreach (Edge edge in route.Edges())
{
//if (!first.HasValue)
//{
// first = edge;
// time = time + this.WeightMatrix[0][edge.From];
//}
time = time + this.WeightMatrix[edge.From][edge.To];
//last = edge;
}
//if (last.HasValue)
//{
// time = time + this.WeightMatrix[last.Value.To][0];
//}
return(this.Time(time, route.Count));
}
/// <summary>
/// Executes a solver procedure.
/// </summary>
/// <param name="problem"></param>
/// <returns></returns>
internal override MaxTimeSolution Solve(MaxTimeProblem problem)
{
float lambda = _lambda;
var vrpRouter =
new CheapestInsertionSolverWithImprovements(problem.Max.Value, problem.DeliveryTime.Value, 10, 0.10f, true, _thresholdPercentage, true, 0.75f);
MaxTimeSolution originalSolution = vrpRouter.Solve(
problem);
for (int roundX = 0; roundX < originalSolution.Count; roundX++)
{ // keep looping on rounds.
for (int roundY = 0; roundY < roundX; roundY++)
{ // keep looping on rounds with a smaller index not equal to the current round.
if (roundX != roundY)
{ // routes are different.
if (this.Overlaps(problem, originalSolution.Route(roundX), originalSolution.Route(roundY)))
{ // only check routes that overlap.
double tau = double.MinValue;
var penalizations = new Dictionary <Edge, int>();
//bool improvement = true;
//while (improvement)
//{ // keep looping until no more improvement is found.
// improvement = false;
while (true)
{ // keep trying to improve until the tau limit is exceeded.
// calculate the route sizes before.
double route1ActualBefore = problem.Time(originalSolution.Route(roundX));
double route2ActualBefore = problem.Time(originalSolution.Route(roundY));
// copy orignal solution.
var solution = (originalSolution.Clone() as MaxTimeSolution);
// apply penalties.
foreach (KeyValuePair <Edge, int> penalty in penalizations)
{
problem.Penalize(penalty.Key, (double)penalty.Value * lambda);
}
// apply the inter-route improvements.
int countBefore = solution.Route(roundX).Count + solution.Route(roundY).Count;
int countAfter;
if (this.ImproveInterRoute(problem, solution, roundX, roundY, problem.Max.Value))
{ // the improve inter route succeeded.
if (!solution.IsValid())
{
throw new Exception();
}
//improvement_inter = true;
countAfter = solution.Route(roundX).Count + solution.Route(roundY).Count;
if (countBefore != countAfter)
{
throw new Exception();
}
// apply the intra-route improvements.
solution[roundX] = this.ImproveIntraRoute(problem, solution.Route(roundX), solution[roundX]);
solution[roundY] = this.ImproveIntraRoute(problem, solution.Route(roundY), solution[roundY]);
// recalculate weights.
solution[roundX] = problem.Time(solution.Route(roundX));
solution[roundY] = problem.Time(solution.Route(roundY));
}
// check customer counts.
countAfter = solution.Route(roundX).Count + solution.Route(roundY).Count;
if (countBefore != countAfter)
{
throw new Exception();
}
// undo the penalizations.
problem.ResetPenalizations();
// check against the orginal objective function.
double route1ActualAfter = problem.Time(solution.Route(roundX));
double route2ActualAfter = problem.Time(solution.Route(roundY));
if (route1ActualAfter + route2ActualAfter < route1ActualBefore + route2ActualBefore - 0.001 &&
route1ActualAfter < problem.Max.Value && route2ActualAfter < problem.Max.Value)
{ // there is improvement!
originalSolution = solution;
//improvement = true;
OsmSharp.Logging.Log.TraceEvent("OsmSharp.Routing.VRP.NoDepot.MaxTime.VNS.GuidedVNS", TraceEventType.Information,
"IMPROVEMENT: {0}->{1}",
route1ActualBefore + route2ActualBefore, route1ActualAfter + route2ActualAfter);
}
// select arc to be penalized.
IRoute route1 = originalSolution.Route(roundX);
IRoute route2 = originalSolution.Route(roundY);
double u = double.MinValue;
var penalizingEdge = new Edge();
double totalP = 0;
foreach (Edge edge in route1.Edges())
{
int edgeP;
if (!penalizations.TryGetValue(edge, out edgeP))
{
edgeP = 0;
}
totalP = totalP + edgeP;
double edgeU = ((lambda * (double)edgeP) + problem.WeightMatrix[edge.From][edge.To]) /
((double)edgeP + 1.0);
if (u <= edgeU)
{
penalizingEdge = edge;
u = edgeU;
}
}
foreach (Edge edge in route2.Edges())
{
int edgeP;
if (!penalizations.TryGetValue(edge, out edgeP))
{
edgeP = 0;
}
totalP = totalP + edgeP;
double edgeU = ((lambda * (double)edgeP) + problem.WeightMatrix[edge.From][edge.To]) /
((double)edgeP + 1.0);
if (u <= edgeU)
{
penalizingEdge = edge;
u = edgeU;
}
}
// actually penalize the edge.
int p;
if (!penalizations.TryGetValue(penalizingEdge, out p))
{
p = 1;
}
else
{
p++;
}
penalizations[penalizingEdge] = p;
// evaluate or set tau.
if (tau > double.MinValue)
{ // evaluate if penalizations should end.
if (tau <= lambda * totalP)
{ // the penalization should end!
break;
}
}
else
{ // first edge being penalized.
tau = lambda * problem.WeightMatrix[penalizingEdge.From][penalizingEdge.To] / 10;
}
}
}
}
}
}
return(originalSolution);
}
/// <summary>
/// Applies inter-improvements by exchanging parts of the route(s).
/// </summary>
/// <param name="problem"></param>
/// <param name="solution"></param>
/// <param name="route1_idx"></param>
/// <param name="route2_idx"></param>
/// <param name="max"></param>
/// <returns></returns>
public bool Improve(MaxTimeProblem problem, MaxTimeSolution solution,
int route1_idx, int route2_idx, double max)
{
int max_window = 40;
IRoute route1 = solution.Route(route1_idx);
IRoute route2 = solution.Route(route2_idx);
int route1_customers = route1.Count;
int route2_customers = route2.Count;
double[] route1_cumul = problem.TimeCumul(route1);
double[] route2_cumul = problem.TimeCumul(route2);
// build all edge weights.
List <Edge> route1_edges = new List <Edge>(route1.Edges());
List <Edge> route2_edges = new List <Edge>(route2.Edges());
double[] route1_weights = new double[route1_edges.Count];
for (int idx = 0; idx < route1_edges.Count; idx++)
{
Edge edge = route1_edges[idx];
route1_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
}
double[] route2_weights = new double[route2_edges.Count];
for (int idx = 0; idx < route2_edges.Count; idx++)
{
Edge edge = route2_edges[idx];
route2_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
}
List <EdgePair> route2_pairs = new List <EdgePair>();
for (int i_idx = 0; i_idx < route2_edges.Count - 2; i_idx++)
{
Edge i = route2_edges[i_idx];
double i_weight = route2_weights[i_idx];
double weight_before_i = route2_cumul[i_idx];
int k_idx_max = route2_edges.Count;
if (k_idx_max > i_idx + 2 + max_window)
{
k_idx_max = i_idx + 2 + max_window;
}
for (int k_idx = i_idx + 2; k_idx < k_idx_max; k_idx++)
{
Edge k = route2_edges[k_idx];
double k_weight = route2_weights[k_idx];
double weight_after_k = route2_cumul[route2_cumul.Length - 1] - route2_cumul[k_idx + 1];
double weight_between_route = route2_cumul[k_idx] - route2_cumul[i_idx + 1];
route2_pairs.Add(new EdgePair()
{
First = i,
FirstWeight = i_weight,
Second = k,
SecondWeight = k_weight,
Between = new List <int>(route2.Between(i.To, k.From)),
WeightTotal = i_weight + k_weight,
WeightAfter = weight_after_k,
WeightBefore = weight_before_i,
WeightBetween = weight_between_route,
CustomersBetween = k_idx - i_idx
});
}
}
// build all edge pairs.
for (int i_idx = 0; i_idx < route1_edges.Count - 2; i_idx++)
{
Edge i = route1_edges[i_idx];
double i_weight = route1_weights[i_idx];
double weight_before_i = route1_cumul[i_idx];
int k_idx_max = route1_edges.Count;
if (k_idx_max > i_idx + 2 + max_window)
{
k_idx_max = i_idx + 2 + max_window;
}
for (int k_idx = i_idx + 2; k_idx < k_idx_max; k_idx++)
{
Edge k = route1_edges[k_idx];
double k_weight = route1_weights[k_idx];
double weight_after_k = route1_cumul[route1_cumul.Length - 1] - route1_cumul[k_idx + 1];
double weight_between_route = route1_cumul[k_idx] - route1_cumul[i_idx + 1];
EdgePair pair1 = new EdgePair()
{
First = i,
FirstWeight = i_weight,
Second = k,
SecondWeight = k_weight,
Between = new List <int>(route1.Between(i.To, k.From)),
WeightTotal = i_weight + k_weight,
WeightAfter = weight_after_k,
WeightBefore = weight_before_i,
WeightBetween = weight_between_route,
CustomersBetween = k_idx - i_idx
};
foreach (EdgePair pair2 in route2_pairs)
{
double existing_weight = pair1.WeightTotal + pair2.WeightTotal;
//double new_weight = 0;
// get first route new.
double new_weight = problem.WeightMatrix[pair1.First.From][pair2.First.To];
//new_weight = first_route1_new;
if (new_weight > existing_weight - 0.001)
{
continue;
}
double first_route2_new = problem.WeightMatrix[pair2.First.From][pair1.First.To];
new_weight = new_weight + first_route2_new;
if (new_weight > existing_weight - 0.001)
{
continue;
}
double second_route1_new = problem.WeightMatrix[pair1.Second.From][pair2.Second.To];
new_weight = new_weight + second_route1_new;
if (new_weight > existing_weight - 0.001)
{
continue;
}
double second_route2_new = problem.WeightMatrix[pair2.Second.From][pair1.Second.To];
new_weight = new_weight + second_route2_new;
if (new_weight < existing_weight - 0.001)
{ // there is a decrease in total weight; check bounds.
double route1_weight = pair1.WeightBefore + pair2.WeightBetween + pair1.WeightAfter;
double route2_weight = pair2.WeightBefore + pair1.WeightBetween + pair2.WeightAfter;
// calculate the maximum.
int route1_customers_between = pair1.CustomersBetween;
int route2_customers_between = pair1.CustomersBetween;
route1_weight = problem.Time(route1_weight,
route1_customers - route1_customers_between + route2_customers_between);
route2_weight = problem.Time(route2_weight,
route2_customers - route2_customers_between + route1_customers_between);
if (route1_weight < max && route2_weight < max)
{
MaxTimeSolution solution_copy = solution.Clone() as MaxTimeSolution;
List <int> route1_between = pair1.Between;
List <int> route2_between = pair2.Between;
route1.ReplaceEdgeFrom(pair1.First.From, pair1.Second.To);
route2.ReplaceEdgeFrom(pair2.First.From, pair2.Second.To);
int previous = pair1.First.From;
for (int idx = 0; idx < route2_between.Count; idx++)
{
route1.ReplaceEdgeFrom(previous, route2_between[idx]);
previous = route2_between[idx];
}
route1.ReplaceEdgeFrom(previous, pair1.Second.To);
previous = pair2.First.From;
for (int idx = 0; idx < route1_between.Count; idx++)
{
route2.ReplaceEdgeFrom(previous, route1_between[idx]);
previous = route1_between[idx];
}
route2.ReplaceEdgeFrom(previous, pair2.Second.To);
if (!solution.IsValid())
{
throw new Exception();
}
return(true);
}
}
}
}
}
return(false);
}
/// <summary>
/// Tries to relocate customers using the source the same as the CrossExchange but places customers using cheapest insertion.
/// </summary>
/// <param name="problem"></param>
/// <param name="solution"></param>
/// <param name="route1_idx"></param>
/// <param name="route2_idx"></param>
/// <param name="max"></param>
/// <returns></returns>
public bool Improve(MaxTimeProblem problem, MaxTimeSolution solution,
int route1_idx, int route2_idx, double max)
{
int max_window = 10;
IRoute route1 = solution.Route(route1_idx);
IRoute route2 = solution.Route(route2_idx);
double total_before = problem.Time(solution.Route(route1_idx)) +
problem.Time(solution.Route(route2_idx));
int route1_customers = route1.Count;
int route2_customers = route2.Count;
double[] route1_cumul = problem.TimeCumul(route1);
double[] route2_cumul = problem.TimeCumul(route2);
// build all edge weights.
List <Edge> route1_edges = new List <Edge>(route1.Edges());
List <Edge> route2_edges = new List <Edge>(route2.Edges());
double[] route1_weights = new double[route1_edges.Count];
for (int idx = 0; idx < route1_edges.Count; idx++)
{
Edge edge = route1_edges[idx];
route1_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
}
double[] route2_weights = new double[route2_edges.Count];
for (int idx = 0; idx < route2_edges.Count; idx++)
{
Edge edge = route2_edges[idx];
route2_weights[idx] = problem.WeightMatrix[edge.From][edge.To];
}
List <EdgePair> route2_pairs = new List <EdgePair>();
for (int i_idx = 0; i_idx < route2_edges.Count - 2; i_idx++)
{
Edge i = route2_edges[i_idx];
double i_weight = route2_weights[i_idx];
double weight_before_i = route2_cumul[i_idx];
int k_idx_max = route2_edges.Count;
if (k_idx_max > i_idx + 2 + max_window)
{
k_idx_max = i_idx + 2 + max_window;
}
for (int k_idx = i_idx + 2; k_idx < k_idx_max; k_idx++)
{
Edge k = route2_edges[k_idx];
double k_weight = route2_weights[k_idx];
double weight_after_k = route2_cumul[route2_cumul.Length - 1] - route2_cumul[k_idx + 1];
double weight_between_route = route2_cumul[k_idx] - route2_cumul[i_idx + 1];
route2_pairs.Add(new EdgePair()
{
First = i,
FirstWeight = i_weight,
Second = k,
SecondWeight = k_weight,
Between = new List <int>(route2.Between(i.To, k.From)),
WeightTotal = i_weight + k_weight,
WeightAfter = weight_after_k,
WeightBefore = weight_before_i,
WeightBetween = weight_between_route,
CustomersBetween = k_idx - i_idx
});
}
}
// try to relocate all and find best pair.
double route1_weight = route1_cumul[route1_cumul.Length - 1];
EdgePair best = null;
CheapestInsertionResult best_result = new CheapestInsertionResult();
double best_extra = double.MaxValue;
foreach (EdgePair pair2 in route2_pairs)
{
// calculate cheapest insertion.
CheapestInsertionResult result =
CheapestInsertionHelper.CalculateBestPlacement(problem, route1,
pair2.First.To, pair2.Second.From);
double extra_route2 = problem.WeightMatrix[pair2.First.From][pair2.Second.To];
// check if the result has a net-decrease.
if (result.Increase + extra_route2 < pair2.WeightTotal - 0.01)
{ // there is a net decrease.
// calculate the real increase.
double new_weight = problem.Time(route1_weight + result.Increase + pair2.WeightBetween, route1_customers +
pair2.CustomersBetween);
// check the max.
if (new_weight < max && new_weight < best_extra)
{ // the route is smaller than max.
best_extra = new_weight;
best_result = result;
best = pair2;
}
}
}
if (best != null)
{
if (route2.Last == best.Second.To)
{
//throw new Exception();
}
route2.ReplaceEdgeFrom(best.First.From, best.Second.To);
int previous = best_result.CustomerBefore;
foreach (int customer in best.Between)
{
route1.ReplaceEdgeFrom(previous, customer);
previous = customer;
}
route1.ReplaceEdgeFrom(previous, best_result.CustomerAfter);
// check validity.
if (!route2.IsValid())
{
throw new Exception();
}
if (!route1.IsValid())
{
throw new Exception();
}
if (route1.Count + route2.Count != route1_customers + route2_customers)
{
throw new Exception();
}
double total_after = problem.Time(solution.Route(route1_idx)) +
problem.Time(solution.Route(route2_idx));
if (total_after >= total_before)
{
throw new Exception("this is not an improvement!");
}
return(true);
}
return(false);
}
/// <summary>
/// Calculates the time of one route.
/// </summary>
/// <param name="route"></param>
/// <returns></returns>
public double Time(IRoute route)
{
double time = 0;
foreach(Edge edge in route.Edges())
{
time = time + this.WeightMatrix[edge.From][edge.To];
}
return this.Time(time, route.Count);
}
/// <summary>
/// Try and merge route2 into route1.
/// </summary>
/// <param name="problem"></param>
/// <param name="solution"></param>
/// <param name="route1_idx"></param>
/// <param name="route2_idx"></param>
/// <param name="max"></param>
/// <returns></returns>
private MergeResult TryMerge(MaxTimeProblem problem, MaxTimeSolution solution,
int route1_idx, int route2_idx, double max)
{
// get the route weights.
double route1_weight = solution[route1_idx];
double route2_weight = solution[route2_idx];
// creates a result.
MergeResult result = new MergeResult();
result.Weight = double.MaxValue;
// get the two routes.
IRoute route1 = solution.Route(route1_idx);
IRoute route2 = solution.Route(route2_idx);
// just first do the case where both routes are of zero length.
if (route1.Count == 1 && route2.Count == 1)
{ // calculate the increase when joining the two points.
foreach (int customer1 in route1)
{
foreach (int customer2 in route2)
{
double difference = problem.WeightMatrix[customer1][customer2] +
problem.WeightMatrix[customer2][customer1];
double new_route_weight = route1_weight + difference + route2_weight;
if (new_route_weight < max)
{
result.Weight = difference;
result.RouteSourceId = route2_idx;
result.RouteTargetId = route1_idx;
result.CustomerSourceSource = customer2;
result.CustomerSourceTarget = customer2;
result.CustomerTargetSource = customer1;
return(result);
}
}
}
}
foreach (Edge route1_edge in route1.Edges())
{ // loop over all route1 edges.
// calculate weight of the current edge.
double route1_edge_weight = problem.WeightMatrix[route1_edge.From][route1_edge.To];
double route1_edge_without = route1_weight - route1_edge_weight;
if (route2.Count == 1)
{ // there is only one customer.
foreach (int customer2 in route2)
{
//// calculate weight of the current edge.
//double route2_edge_weight = problem.WeightMatrix[route2_edge.From][route2_edge.To];
//double route2_edge_without = route2_weight - route2_edge_weight;
double new_edges_weight = problem.WeightMatrix[route1_edge.From][customer2] +
problem.WeightMatrix[customer2][route1_edge.To];
double difference = problem.WeightDifferenceAfterMerge(solution,
new_edges_weight - (route1_edge_weight));
// check if the max bound is not violated.
double new_route_weight = route1_edge_without + difference + route2_weight; // the customer remain the same.
if (new_route_weight < max)
{
// the difference is smaller than the current result.
if (difference < result.Weight)
{
result.Weight = difference;
result.RouteSourceId = route2_idx;
result.RouteTargetId = route1_idx;
result.CustomerSourceSource = customer2;
result.CustomerSourceTarget = customer2;
result.CustomerTargetSource = route1_edge.From;
}
}
}
}
else
{ // there is at least one edge.
foreach (Edge route2_edge in route2.Edges())
{ // loop over all route2 edges.
// calculate weight of the current edge.
double route2_edge_weight = problem.WeightMatrix[route2_edge.From][route2_edge.To];
double route2_edge_without = route2_weight - route2_edge_weight;
double new_edges_weight = problem.WeightMatrix[route1_edge.From][route2_edge.To] +
problem.WeightMatrix[route2_edge.From][route1_edge.To];
double difference = problem.WeightDifferenceAfterMerge(solution,
new_edges_weight - (route1_edge_weight + route2_edge_weight));
// check if the max bound is not violated.
double new_route_weight = route1_edge_weight + route2_edge_without + new_edges_weight; // the customer remain the same.
if (new_route_weight < max)
{
// the difference is smaller than the current result.
if (difference < result.Weight)
{
result.Weight = difference;
result.RouteSourceId = route2_idx;
result.RouteTargetId = route1_idx;
result.CustomerSourceSource = route2_edge.To;
result.CustomerSourceTarget = route2_edge.From;
result.CustomerTargetSource = route1_edge.From;
}
}
}
}
}
return(result);
}
/// <summary>
/// Calculates the time of one route.
/// </summary>
/// <param name="route"></param>
/// <returns></returns>
public double Time(IRoute route)
{
double time = 0;
//Edge? first = null;
//Edge? last = null;
foreach (Edge edge in route.Edges())
{
//if (!first.HasValue)
//{
// first = edge;
// time = time + this.WeightMatrix[0][edge.From];
//}
time = time + this.WeightMatrix[edge.From][edge.To];
//last = edge;
}
//if (last.HasValue)
//{
// time = time + this.WeightMatrix[last.Value.To][0];
//}
return this.Time(time, route.Count);
}
