private void Run()
{
// create a complete graph and run Kruskal with maximum degree constraint 2
CompleteGraph graph = new CompleteGraph(Nodes.Count, Directedness.Undirected);
Func <Arc, double> arcCost = (arc => Cost(Nodes[graph.GetNodeIndex(graph.U(arc))],
Nodes[graph.GetNodeIndex(graph.V(arc))]));
Kruskal <double> kruskal = new Kruskal <double>(graph, arcCost, _ => 2);
kruskal.Run();
Dictionary <Node, Arc> firstArc = new Dictionary <Node, Arc>();
Dictionary <Node, Arc> secondArc = new Dictionary <Node, Arc>();
foreach (var arc in kruskal.Forest)
{
var u = graph.U(arc);
(firstArc.ContainsKey(u) ? secondArc : firstArc)[u] = arc;
var v = graph.V(arc);
(firstArc.ContainsKey(v) ? secondArc : firstArc)[v] = arc;
}
foreach (var startNode in graph.Nodes())
{
if (kruskal.Degree[startNode] == 1)
{
Arc prevArc = Arc.Invalid;
Node n = startNode;
while (true)
{
tour.Add(Nodes[graph.GetNodeIndex(n)]);
if (prevArc != Arc.Invalid && kruskal.Degree[n] == 1)
{
break;
}
Arc arc1 = firstArc[n];
prevArc = (arc1 != prevArc ? arc1 : secondArc[n]);
n = graph.Other(prevArc, n);
}
tour.Add(Nodes[graph.GetNodeIndex(startNode)]);
break;
}
}
TourCost = TspUtils.GetTourCost(tour, Cost);
}
private void Run()
{
CompleteGraph graph = new CompleteGraph(Nodes.Count, Directedness.Undirected);
Func <Arc, double> cost = (Arc arc) => Cost(Nodes[graph.GetNodeIndex(graph.U(arc))], Nodes[graph.GetNodeIndex(graph.V(arc))]);
Kruskal <double> kruskal = new Kruskal <double>(graph, cost, (Node _) => 2);
kruskal.Run();
Dictionary <Node, Arc> dictionary = new Dictionary <Node, Arc>();
Dictionary <Node, Arc> dictionary2 = new Dictionary <Node, Arc>();
foreach (Arc item in kruskal.Forest)
{
Node key = graph.U(item);
((!dictionary.ContainsKey(key)) ? dictionary : dictionary2)[key] = item;
Node key2 = graph.V(item);
((!dictionary.ContainsKey(key2)) ? dictionary : dictionary2)[key2] = item;
}
foreach (Node item2 in graph.Nodes())
{
if (kruskal.Degree[item2] == 1)
{
Arc arc2 = Arc.Invalid;
Node node = item2;
while (true)
{
tour.Add(Nodes[graph.GetNodeIndex(node)]);
if (arc2 != Arc.Invalid && kruskal.Degree[node] == 1)
{
break;
}
Arc arc3 = dictionary[node];
arc2 = ((!(arc3 != arc2)) ? dictionary2[node] : arc3);
node = graph.Other(arc2, node);
}
tour.Add(Nodes[graph.GetNodeIndex(item2)]);
break;
}
}
TourCost = TspUtils.GetTourCost <TNode>((IEnumerable <TNode>)tour, Cost);
}
/// Initializes the 2-OPT optimizer with the supplied tour.
/// \param cost The cost function (should be symmetrical).
/// \param tour The tour to improve with 2-OPT. The starting node must be repeated at the end.
/// \param tourCost The known cost of \c tour. Use this parameter to speed up initialization.
/// If \c null is supplied, then the tour cost is recalculated.
public Opt2Tsp(Func <TNode, TNode, double> cost, IEnumerable <TNode> tour, double?tourCost)
{
Cost = cost;
this.tour = tour.ToList();
TourCost = tourCost ?? TspUtils.GetTourCost(tour, cost);
}
public Opt2Tsp(Func <TNode, TNode, double> cost, IEnumerable <TNode> tour, double?tourCost)
{
Cost = cost;
this.tour = Enumerable.ToList <TNode>(tour);
TourCost = ((!tourCost.HasValue) ? TspUtils.GetTourCost <TNode>(tour, cost) : tourCost.Value);
}