protected override void InternalCompute()
{
var cancelManager = this.Services.CancelManager;
TVertex root;
if (!this.TryGetRootVertex(out root))
{
throw new InvalidOperationException("root vertex not set");
}
if (this.pairs == null)
{
throw new InvalidOperationException("pairs not set");
}
var gpair = GraphExtensions.ToAdjacencyGraph(this.pairs);
var disjointSet = new ForestDisjointSet <TVertex>();
var vancestors = new Dictionary <TVertex, TVertex>();
var dfs = new DepthFirstSearchAlgorithm <TVertex, TEdge>(this, this.VisitedGraph, new Dictionary <TVertex, GraphColor>(this.VisitedGraph.VertexCount));
dfs.InitializeVertex += v => disjointSet.MakeSet(v);
dfs.DiscoverVertex += v => vancestors[v] = v;
dfs.TreeEdge += edge =>
{
disjointSet.Union(edge.Source, edge.Target);
vancestors[disjointSet.FindSet(edge.Source)] = edge.Source;
};
dfs.FinishVertex += v =>
{
foreach (var e in gpair.OutEdges(v))
{
if (dfs.VertexColors[e.Target] == GraphColor.Black)
{
this.ancestors[EdgeExtensions.ToVertexPair <TVertex, SEquatableEdge <TVertex> >(e)] = vancestors[disjointSet.FindSet(e.Target)];
}
}
};
// go!
dfs.Compute(root);
}
protected override void InternalCompute()
{
var cancelManager = this.Services.CancelManager;
// matrix i,j -> path
this.data.Clear();
var vertices = this.VisitedGraph.Vertices;
var edges = this.VisitedGraph.Edges;
// prepare the matrix with initial costs
// walk each edge and add entry in cost dictionary
foreach (var edge in edges)
{
var ij = EdgeExtensions.ToVertexPair <TVertex, TEdge>(edge);
var cost = this.weights(edge);
VertexData value;
if (!data.TryGetValue(ij, out value))
{
data[ij] = new VertexData(cost, edge);
}
else if (cost < value.Distance)
{
data[ij] = new VertexData(cost, edge);
}
}
if (cancelManager.IsCancelling)
{
return;
}
// walk each vertices and make sure cost self-cost 0
foreach (var v in vertices)
{
data[new SEquatableEdge <TVertex>(v, v)] = new VertexData(0, default(TEdge));
}
if (cancelManager.IsCancelling)
{
return;
}
// iterate k, i, j
foreach (var vk in vertices)
{
if (cancelManager.IsCancelling)
{
return;
}
foreach (var vi in vertices)
{
var ik = new SEquatableEdge <TVertex>(vi, vk);
VertexData pathik;
if (data.TryGetValue(ik, out pathik))
{
foreach (var vj in vertices)
{
var kj = new SEquatableEdge <TVertex>(vk, vj);
VertexData pathkj;
if (data.TryGetValue(kj, out pathkj))
{
double combined = this.distanceRelaxer.Combine(pathik.Distance, pathkj.Distance);
var ij = new SEquatableEdge <TVertex>(vi, vj);
VertexData pathij;
if (data.TryGetValue(ij, out pathij))
{
if (this.distanceRelaxer.Compare(combined, pathij.Distance) < 0)
{
data[ij] = new VertexData(combined, vk);
}
}
else
{
data[ij] = new VertexData(combined, vk);
}
}
}
}
}
}
// check negative cycles
foreach (var vi in vertices)
{
var ii = new SEquatableEdge <TVertex>(vi, vi);
VertexData value;
if (data.TryGetValue(ii, out value) &&
value.Distance < 0)
{
throw new NegativeCycleGraphException();
}
}
}