public void convertTree() {
int L = labelVocab.size();
this.treeRoot = new TreeNode<TreeNode, Integer>(0, 0, L, null);
TreeNode<TreeNode, Integer>[] treeNodes = new TreeNode[L + 1];
Queue<GraphNode<Integer>> queue = new LinkedList<GraphNode<Integer>>();
queue.add(this.root);
treeNodes[L] = this.treeRoot;
while (!queue.isEmpty()) {
GraphNode<Integer> mstNode = queue.poll();
TreeNode<TreeNode, Integer> node = treeNodes[mstNode.getId()];
if (tree.hasOutEdges(mstNode)) {
for (GraphEdge edge : tree.getOutEdges(mstNode)) {
GraphNode<Integer> mstChild = edge.getTarget();
int labelIdx = mstChild.getId();
TreeNode<TreeNode, Integer> childNode =
new TreeNode<TreeNode, Integer>(
node.getNextChildIndex(), node.getLevel() + 1, labelIdx, node);
node.addChild(childNode.getIndex(), childNode);
treeNodes[labelIdx] = childNode;
queue.add(mstChild);
}
}
}
}
@Override
public void buildTree() {
int L = getNumLabels();
// create raw label graph
DirectedGraph<Integer> labelGraph = new DirectedGraph<Integer>();
// create label nodes
GraphNode<Integer>[] graphNodes = new GraphNode[L + 1];
for (int ll = 0; ll < L + 1; ll++) {
graphNodes[ll] = new GraphNode<Integer>(ll);
}
root = graphNodes[L];
SparseVector[] outWeights = new SparseVector[L];
for (int ll = 0; ll < L; ll++) {
outWeights[ll] = new SparseVector();
}
// pair frequencies
for (int dd = 0; dd < labels.length; dd++) {
int[] docLabels = labels[dd];
for (int ii = 0; ii < docLabels.length; ii++) {
for (int jj = 0; jj < docLabels.length; jj++) {
if (ii == jj) {
continue;
}
Double weight = outWeights[docLabels[jj]].get(docLabels[ii]);
if (weight == null) {
outWeights[docLabels[jj]].set(docLabels[ii], 1.0);
} else {
outWeights[docLabels[jj]].set(docLabels[ii], weight + 1.0);
}
}
}
}
// edges
for (int l = 0; l < L; l++) {
for (int ii : outWeights[l].getIndices()) {
double weight = outWeights[l].get(ii) / labelFreqs[ii];
GraphNode<Integer> source = graphNodes[l];
GraphNode<Integer> target = graphNodes[ii];
labelGraph.addEdge(source, target, -weight);
}
}
// root's edges
int maxLabelFreq = StatUtils.max(labelFreqs);
for (int l = 0; l < L; l++) {
double weight = (double) labelFreqs[l] / maxLabelFreq;
labelGraph.addEdge(root, graphNodes[l], -weight);
}
EdmondsMST<Integer> dmst = new EdmondsMST<Integer>(root, labelGraph);
this.tree = dmst.getMinimumSpanningTree();
convertTree();
this.labelVocab.add("root");
}