private WeightedMultigraph<Vertex, LabeledWeightedEdge> step1() {
logger.debug("<enter");
WeightedMultigraph<Vertex, LabeledWeightedEdge> g =
new WeightedMultigraph<Vertex, LabeledWeightedEdge>(LabeledWeightedEdge.class);
for (int i = 0; i < steinerNodes.size(); i++) {
g.addVertex(steinerNodes.get(i));
}
BellmanFordShortestPath<Vertex, LabeledWeightedEdge> path;
for (int i = 0; i < steinerNodes.size(); i++) {
path =
new BellmanFordShortestPath<Vertex, LabeledWeightedEdge>(this.graph, steinerNodes.get(i));
for (int j = 0; j < steinerNodes.size(); j++) {
if (i == j) continue;
if (g.containsEdge(steinerNodes.get(i), steinerNodes.get(j))) continue;
String id = "e" + String.valueOf(i) + String.valueOf(j);
LabeledWeightedEdge e = new LabeledWeightedEdge(id, new URI(id, null, null), null);
g.addEdge(steinerNodes.get(i), steinerNodes.get(j), e);
g.setEdgeWeight(e, path.getCost(steinerNodes.get(j)));
}
}
logger.debug("exit>");
return g;
}
private WeightedMultigraph<Vertex, LabeledWeightedEdge> step2(
WeightedMultigraph<Vertex, LabeledWeightedEdge> g1) {
logger.debug("<enter");
KruskalMinimumSpanningTree<Vertex, LabeledWeightedEdge> mst =
new KruskalMinimumSpanningTree<Vertex, LabeledWeightedEdge>(g1);
// System.out.println("Total MST Cost: " + mst.getSpanningTreeCost());
Set<LabeledWeightedEdge> edges = mst.getEdgeSet();
WeightedMultigraph<Vertex, LabeledWeightedEdge> g2 =
new WeightedMultigraph<Vertex, LabeledWeightedEdge>(LabeledWeightedEdge.class);
List<LabeledWeightedEdge> edgesSortedByLabel = new ArrayList<LabeledWeightedEdge>();
for (LabeledWeightedEdge e : edges) edgesSortedByLabel.add(e);
Collections.sort(edgesSortedByLabel, new EdgeComparatorByLabel());
for (LabeledWeightedEdge edge : edgesSortedByLabel) {
// //just for test, forcing to select another equal minimal spanning tree
// if (g1.getEdgeSource(edge).getLabel().equalsIgnoreCase("v1") &&
// g1.getEdgeTarget(edge).getLabel().equalsIgnoreCase("v3") ) {
// Vertex v2 = steinerNodes.get(1);
// g2.addVertex(g1.getEdgeTarget(edge));
// g2.addVertex(v2);
// LabeledWeightedEdge e = new LabeledWeightedEdge("e");
// g2.setEdgeWeight(e, g1.getEdgeWeight(edge));
// g2.addEdge(g1.getEdgeTarget(edge), v2, e);
// } else
{
g2.addVertex(edge.getSource());
g2.addVertex(edge.getTarget());
g2.addEdge(edge.getSource(), edge.getTarget(), edge);
}
}
logger.debug("exit>");
return g2;
}
private WeightedMultigraph<Vertex, LabeledWeightedEdge> step3(
WeightedMultigraph<Vertex, LabeledWeightedEdge> g2) {
logger.debug("<enter");
WeightedMultigraph<Vertex, LabeledWeightedEdge> g3 =
new WeightedMultigraph<Vertex, LabeledWeightedEdge>(LabeledWeightedEdge.class);
Set<LabeledWeightedEdge> edges = g2.edgeSet();
DijkstraShortestPath<Vertex, LabeledWeightedEdge> path;
Vertex source, target;
for (LabeledWeightedEdge edge : edges) {
source = edge.getSource();
target = edge.getTarget();
path = new DijkstraShortestPath<Vertex, LabeledWeightedEdge>(this.graph, source, target);
List<LabeledWeightedEdge> pathEdges = path.getPathEdgeList();
if (pathEdges == null) continue;
for (int i = 0; i < pathEdges.size(); i++) {
if (g3.edgeSet().contains(pathEdges.get(i))) continue;
source = pathEdges.get(i).getSource();
target = pathEdges.get(i).getTarget();
if (!g3.vertexSet().contains(source)) g3.addVertex(source);
if (!g3.vertexSet().contains(target)) g3.addVertex(target);
g3.addEdge(source, target, pathEdges.get(i));
}
}
logger.debug("exit>");
return g3;
}
public EdgeBetweennessGraph(WeightedMultigraph<String, DefaultWeightedEdge> originalGraph) {
super(DefaultWeightedEdge.class); // Constructor inherented from parent class
// 1. Initialize the edge betweenness digraph
// 1.1. Add vertices
for (String thisVertex : originalGraph.vertexSet()) this.addVertex(thisVertex);
// 1.2. Add edges
for (DefaultWeightedEdge thisEdge : originalGraph.edgeSet()) {
DefaultWeightedEdge newEdge = new DefaultWeightedEdge();
String sendingName = originalGraph.getEdgeSource(thisEdge);
String receivingName = originalGraph.getEdgeTarget(thisEdge);
this.addEdge(sendingName, receivingName, newEdge);
this.setEdgeWeight(newEdge, 0.0);
}
// 1.3. Create corresponding unweighted graph
// 1.3.1. Add vertices
WeightedMultigraph<String, DefaultWeightedEdge> originalUnweightedGraph =
new WeightedMultigraph<String, DefaultWeightedEdge>(DefaultWeightedEdge.class);
for (String thisVertex : originalGraph.vertexSet())
originalUnweightedGraph.addVertex(thisVertex);
// 1.3.2. Add edges
for (DefaultWeightedEdge thisEdge : originalGraph.edgeSet()) {
DefaultWeightedEdge newEdge = new DefaultWeightedEdge();
String sendingName = originalGraph.getEdgeSource(thisEdge);
String receivingName = originalGraph.getEdgeTarget(thisEdge);
originalUnweightedGraph.addEdge(sendingName, receivingName, newEdge);
originalUnweightedGraph.setEdgeWeight(newEdge, 1.0);
}
for (String thisVertex : this.vertexSet()) {
// 2. Create shortest-path graph for every vertex by Dijkstra algorithm
Multigraph<String, DefaultEdge> shortestPathDigraph =
DijkstraAlgorithm(originalUnweightedGraph, thisVertex);
// 3. Calculate the contribution of current vertex's shortest-path graph to final edge
// betweenness (Newman algorithm)
SimpleWeightedGraph<String, DefaultWeightedEdge> edgeBetweennessDigraph =
NewmanAlgorithm(shortestPathDigraph, thisVertex);
// 4. Update final edge betweenness digraph with current vertex's shortest-path graph
if (edgeBetweennessDigraph != null)
for (DefaultWeightedEdge thisEdge : edgeBetweennessDigraph.edgeSet()) {
String sourceVertex = edgeBetweennessDigraph.getEdgeSource(thisEdge);
String targetVertex = edgeBetweennessDigraph.getEdgeTarget(thisEdge);
double betweennessWeight = edgeBetweennessDigraph.getEdgeWeight(thisEdge);
DefaultWeightedEdge edgeInWholeGraph = this.getEdge(sourceVertex, targetVertex);
double newWeight = this.getEdgeWeight(edgeInWholeGraph) + betweennessWeight;
this.setEdgeWeight(edgeInWholeGraph, newWeight);
}
}
// 5. Revise the edge betweenness digraph with the original active power digraph
for (DefaultWeightedEdge thisEdge : this.edgeSet()) {
String sourceVertex = this.getEdgeSource(thisEdge);
String targetVertex = this.getEdgeTarget(thisEdge);
double betweennessWeight = this.getEdgeWeight(thisEdge);
DefaultWeightedEdge edgeInWholeGraph = originalGraph.getEdge(sourceVertex, targetVertex);
double newWeight = betweennessWeight / originalGraph.getEdgeWeight(edgeInWholeGraph);
this.setEdgeWeight(thisEdge, newWeight);
// System.out.println("Final edge betweenness between " + sourceVertex + " and " +
// targetVertex + ": " + newWeight);
}
}