/**
* Finds the set of clusters which have the strongest "community structure". The more edges
* removed the smaller and more cohesive the clusters.
*
* @param graph the graph
*/
public Set<Set<V>> transform(Graph<V, E> graph) {
if (mNumEdgesToRemove < 0 || mNumEdgesToRemove > graph.getEdgeCount()) {
throw new IllegalArgumentException("Invalid number of edges passed in.");
}
edges_removed.clear();
for (int k = 0; k < mNumEdgesToRemove; k++) {
BetweennessCentrality<V, E> bc = new BetweennessCentrality<V, E>(graph);
E to_remove = null;
double score = 0;
for (E e : graph.getEdges()) {
Integer weight = mWeight.get(e);
if (bc.getEdgeScore(e) / weight > score) {
to_remove = e;
score = bc.getEdgeScore(e) / weight;
}
}
edges_removed.put(to_remove, graph.getEndpoints(to_remove));
graph.removeEdge(to_remove);
}
WeakComponentClusterer<V, E> wcSearch = new WeakComponentClusterer<V, E>();
Set<Set<V>> clusterSet = wcSearch.transform(graph);
for (Map.Entry<E, Pair<V>> entry : edges_removed.entrySet()) {
Pair<V> endpoints = entry.getValue();
graph.addEdge(entry.getKey(), endpoints.getFirst(), endpoints.getSecond());
}
return clusterSet;
}
private void addEdges() {
// remove old edges if available
Iterator<String> e = edgeLabelMap.keySet().iterator();
while (e.hasNext()) {
graph.removeEdge(e.next());
}
edgeLabelMap.clear();
boolean isDistance = measure.isDistance();
Attribute id = exampleSet.getAttributes().getId();
List<SortableEdge> sortableEdges = new LinkedList<SortableEdge>();
for (int i = 0; i < exampleSet.size(); i++) {
Example example = exampleSet.getExample(i);
for (int j = i + 1; j < exampleSet.size(); j++) {
Example comExample = exampleSet.getExample(j);
if (isDistance)
sortableEdges.add(
new SortableEdge(
example.getValueAsString(id),
comExample.getValueAsString(id),
null,
measure.calculateDistance(example, comExample),
SortableEdge.DIRECTION_INCREASE));
else
sortableEdges.add(
new SortableEdge(
example.getValueAsString(id),
comExample.getValueAsString(id),
null,
measure.calculateSimilarity(example, comExample),
SortableEdge.DIRECTION_DECREASE));
}
}
Collections.sort(sortableEdges);
int numberOfEdges = distanceSlider.getValue();
int counter = 0;
double minStrength = Double.POSITIVE_INFINITY;
double maxStrength = Double.NEGATIVE_INFINITY;
Map<String, Double> strengthMap = new HashMap<String, Double>();
for (SortableEdge sortableEdge : sortableEdges) {
if (counter > numberOfEdges) break;
String idString = edgeFactory.create();
graph.addEdge(
idString,
sortableEdge.getFirstVertex(),
sortableEdge.getSecondVertex(),
EdgeType.UNDIRECTED);
edgeLabelMap.put(idString, Tools.formatIntegerIfPossible(sortableEdge.getEdgeValue()));
double strength = sortableEdge.getEdgeValue();
minStrength = Math.min(minStrength, strength);
maxStrength = Math.max(maxStrength, strength);
strengthMap.put(idString, strength);
counter++;
}
for (Entry<String, Double> entry : strengthMap.entrySet()) {
edgeStrengthMap.put(
entry.getKey(), (entry.getValue() - minStrength) / (maxStrength - minStrength));
}
}