public void ToDotFile(string filename = "tmp.dot", TspTour tour = null)
{
using (var writer = new StreamWriter(filename))
{
writer.WriteLine($"digraph G {{{Environment.NewLine}penwidth=2;");
if (tour?.Length > 1)
{
for (int i = 0; i < tour.Length; i++)
{
var n = tour[i];
var m = tour[(i + 1) % tour.Length];
writer.WriteLine($"{n} -> {m} [label=\"{_dists[n, m]}\",color=red,penwidth=3];");
}
}
for (int n = 0; n < NumNodes; n++)
{
for (int m = n + 1; m < NumNodes; m++)
{
if (_dists[n, m] == NoEdge)
{
continue;
}
if (tour == null || !tour.VisitsEdge(n, m))
{
writer.WriteLine($"{n} -> {m} [dir=none,label=\"{_dists[n, m]}\"];");
}
}
}
writer.WriteLine("}");
}
}
private static void Plot(Graph g, string file, TspTour t = null)
{
g.ToDotFile($"{file}.dot", t);
var p = Process.Start("dot", $"-Tpng -o {file}.png {file}.dot");
p.WaitForExit();
// only on OS X
if (p.ExitCode == 0)
{
Process.Start("open", $"{file}.png");
}
}
private void Exhaustive_internal(TspTour t)
{
if (t.AllVisiteed && _graph.HasEdge(t.LastNode, 0))
{
_tours.Add(t.VisitNext(0));
return;
}
foreach (var next in t.UnvisitedNodes.Where(x => _graph.HasEdge(t.LastNode, x)))
{
// Assuming symmetric distances, we only want one
// directed traversal of a TspTour-Slope
if (_graph.NumNodes > 3 && next == 2 && !t.IsVisited(1))
{
continue;
}
Exhaustive_internal(t.VisitNext(next));
}
}