public G generate(int N, int k, double p) {
G graph = ringLatticeGenerator.generate(N, k);
Set<Edge> edges = new HashSet<Edge>();
for (Edge edge : graph.getEdges()) {
if (random.nextDouble() < p) {
edges.add(edge);
}
}
List<V> vertices = new ArrayList<V>(graph.getVertices().size());
vertices.addAll((Collection<? extends V>) graph.getVertices());
int doubleEdges = 0;
for (Edge edge : edges) {
V source;
if (random.nextBoolean()) {
source = (V) edge.getVertices().getFirst();
} else {
source = (V) edge.getVertices().getSecond();
}
builder.removeEdge(graph, (E) edge);
V target = null;
while (target == null) {
target = vertices.get(random.nextInt(vertices.size()));
if (source == target) target = null;
}
if (builder.addEdge(graph, source, target) == null) doubleEdges++;
}
logger.debug(String.format("Rejected %1$s double edges.", doubleEdges));
return graph;
}
/**
* Returns a list of edge attributes stored in String-String-tuples. The returned list contains
* two entries:
*
* <ul>
* <li>{@link GraphML#SOURCE_ATTR} - <tt>vertexIdx</tt>
* <li>{@link GraphML#TARGET_ATTR} - <tt>vertexIdx</tt>
* </ul>
*
* @param e the edge the attributes are to be returned.
* @return a list of edge attributes.
*/
protected List<Tuple<String, String>> getEdgeAttributes(Edge e) {
List<Tuple<String, String>> attrs = new LinkedList<Tuple<String, String>>();
Vertex v1 = e.getVertices().getFirst();
Vertex v2 = e.getVertices().getSecond();
int idx1 = vertexTmpIds.get(v1);
int idx2 = vertexTmpIds.get(v2);
if (idx1 > 0 && idx2 > 0) {
attrs.add(createTuple(GraphML.SOURCE_ATTR, idx1));
attrs.add(createTuple(GraphML.TARGET_ATTR, idx2));
} else {
throw new IllegalArgumentException("Orphaned edges are not allowed!");
}
return attrs;
}