@Override
public Graph<String, String> createGraph() {
	DirectedOrderedSparseMultigraph<String, String> treeGraph = new DirectedOrderedSparseMultigraph<String, String>();

	Tree root = this.model.getRoot();
	treeGraph.addVertex("Root");
	vertexMap.put("Root", root);
	addTree(treeGraph, root, "Root", new ArrayList<>());

	return new DelegateForest<String, String>(treeGraph);
}
 

private void addTree(DirectedOrderedSparseMultigraph<String, String> treeGraph, Tree node, String parentName,
		List<String> currentParentList) {
	Iterator<Edge> e = node.childIterator();
	double edgeWeightSum = model.getRoot().getSubtreeFrequencySum();

	e = node.childIterator();
	while (e.hasNext()) {
		Edge edge = e.next();
		Tree child = edge.getChild();
		SplitCondition condition = edge.getCondition();
		String childName = vertexFactory.create();
		String edgeName = edgeFactory.create();
		currentParentList.add(parentName);
		currentParentList.add(edgeName);
		pathToRootMap.put(edgeName, currentParentList);
		pathToRootMap.put(childName, currentParentList);

		vertexMap.put(childName, child);
		edgeMap.put(edgeName, condition);
		edgeStrengthMap.put(edgeName, child.getSubtreeFrequencySum() / edgeWeightSum);
		treeGraph.addEdge(edgeName, parentName, childName);
		addTree(treeGraph, child, childName, new ArrayList<>(currentParentList));

		// siblings would use the same list with wrong edges if we did not copy
		currentParentList = new ArrayList<String>(currentParentList);
		currentParentList.remove(edgeName);
	}
}