/// <summary>
/// Computes the PageRank over the <see cref="VisitedGraph"/>.
/// </summary>
public void Compute()
{
VertexDoubleDictionary tempRanks = new VertexDoubleDictionary();
// create filtered graph
FilteredBidirectionalGraph fg = new FilteredBidirectionalGraph(
this.VisitedGraph,
Preds.KeepAllEdges(),
new InDictionaryVertexPredicate(this.ranks)
);
int iter = 0;
double error = 0;
do
{
// compute page ranks
error = 0;
foreach (DictionaryEntry de in this.Ranks)
{
IVertex v = (IVertex)de.Key;
double rank = (double)de.Value;
// compute ARi
double r = 0;
foreach (IEdge e in fg.InEdges(v))
{
r += this.ranks[e.Source] / fg.OutDegree(e.Source);
}
// add sourceRank and store
double newRank = (1 - this.damping) + this.damping * r;
tempRanks[v] = newRank;
// compute deviation
error += Math.Abs(rank - newRank);
}
// swap ranks
VertexDoubleDictionary temp = ranks;
ranks = tempRanks;
tempRanks = temp;
iter++;
}while(error > this.tolerance && iter < this.maxIterations);
Console.WriteLine("{0}, {1}", iter, error);
}
private void BasicFiltering()
{
BidirectionalGraph graph = GraphProvider.FileDependency();
DrawGraph(graph, "filedependency");
Console.WriteLine("Source vertices:");
foreach (NamedVertex v in graph.SelectVertices(Preds.SourceVertex(graph)))
{
Console.WriteLine("\t{0}", v.Name);
}
Console.WriteLine("Sink vertices:");
FilteredVertexEnumerable filteredVertices =
new FilteredVertexEnumerable(
graph.Vertices,
Preds.SinkVertex(graph)
);
foreach (NamedVertex v in filteredVertices)
{
Console.WriteLine("\t{0}", v.Name);
}
}
private void FilterFsm()
{
AdjacencyGraph graph = GraphProvider.Fsm();
// drawing the fsm
DrawGraph(graph, "fsm");
// filtering
// putting all black besides S4
// therefore all the edges touching s4 will be filtered out.
VertexColorDictionary vertexColors = new VertexColorDictionary();
IVertexPredicate pred = new NameEqualPredicate("S4");
foreach (IVertex v in graph.Vertices)
{
if (pred.Test(v))
{
vertexColors[v] = GraphColor.Black;
}
else
{
vertexColors[v] = GraphColor.White;
}
}
IVertexPredicate vp = new NoBlackVertexPredicate(vertexColors);
IEdgePredicate ep = new EdgePredicate(
Preds.KeepAllEdges(),
vp
);
IVertexAndEdgeListGraph filteredGraph = new FilteredVertexAndEdgeListGraph(graph,
ep,
vp
);
DrawGraph(filteredGraph, "fsmfiltered");
}
