public void AttachDistanceRecorderVisitor()
{
AdjacencyGraph g = new AdjacencyGraph(true);
EdgeDoubleDictionary weights = DijkstraShortestPathAlgorithm.UnaryWeightsFromEdgeList(g);
DijkstraShortestPathAlgorithm dij = new DijkstraShortestPathAlgorithm(g,weights);
DistanceRecorderVisitor vis = new DistanceRecorderVisitor();
dij.RegisterDistanceRecorderHandlers(vis);
}
private bool IsOptimal(MaximumFlowAlgorithm maxFlow)
{
// check if mincut is saturated...
FilteredVertexListGraph residualGraph = new FilteredVertexListGraph(
maxFlow.VisitedGraph,
new ReversedResidualEdgePredicate(maxFlow.ResidualCapacities, maxFlow.ReversedEdges)
);
BreadthFirstSearchAlgorithm bfs = new BreadthFirstSearchAlgorithm(residualGraph);
VertexIntDictionary distances = new VertexIntDictionary();
DistanceRecorderVisitor vis = new DistanceRecorderVisitor(distances);
bfs.RegisterDistanceRecorderHandlers(vis);
bfs.Compute(sink);
return distances[source] >= maxFlow.VisitedGraph.VerticesCount;
}
//=======================================================================
// This is a breadth-first search over the residual graph
// (well, actually the reverse of the residual graph).
// Would be cool to have a graph view adaptor for hiding certain
// edges, like the saturated (non-residual) edges in this case.
// Goldberg's implementation abused "distance" for the coloring.
private void GlobalDistanceUpdate()
{
foreach (IVertex u in VisitedGraph.Vertices)
{
Colors[u] = GraphColor.White;
Distances[u] = n;
}
Distances[sink] = 0;
for (int l = 0; l <= maxDistance; ++l)
{
layers[l].ActiveVertices.Clear();
layers[l].InactiveVertices.Clear();
}
maxDistance = maxActive = 0;
minActive = n;
BreadthFirstSearchAlgorithm bfs = new BreadthFirstSearchAlgorithm(
ResidualGraph,
new VertexBuffer(),
Colors
);
DistanceRecorderVisitor vis = new DistanceRecorderVisitor(Distances);
bfs.TreeEdge += new EdgeEventHandler(vis.TreeEdge);
bfs.DiscoverVertex += new VertexEventHandler(GlobalDistanceUpdateHelper);
bfs.Compute(sink);
}
private void GlobalDistanceUpdate()
{
IVertexEnumerator enumerator = this.VisitedGraph.get_Vertices().GetEnumerator();
while (enumerator.MoveNext())
{
IVertex vertex = enumerator.get_Current();
base.Colors.set_Item(vertex, 0);
this.Distances.set_Item(vertex, this.n);
}
this.Distances.set_Item(this.sink, 0);
for (int i = 0; i <= this.maxDistance; i++)
{
this.layers[i].ActiveVertices.Clear();
this.layers[i].InactiveVertices.Clear();
}
this.maxDistance = this.maxActive = 0;
this.minActive = this.n;
BreadthFirstSearchAlgorithm algorithm = new BreadthFirstSearchAlgorithm(this.ResidualGraph, new VertexBuffer(), base.Colors);
DistanceRecorderVisitor visitor = new DistanceRecorderVisitor(this.Distances);
algorithm.TreeEdge += new EdgeEventHandler(visitor, (IntPtr) this.TreeEdge);
algorithm.DiscoverVertex += new VertexEventHandler(this, (IntPtr) this.GlobalDistanceUpdateHelper);
algorithm.Compute(this.sink);
}
