public String toGraphviz() {
StringBuilder builder = new StringBuilder();
builder.append("digraph QuantileDigest {\n").append("\tgraph [ordering=\"out\"];");
final List<Node> nodes = new ArrayList<>();
postOrderTraversal(
root,
new Callback() {
@Override
public boolean process(Node node) {
nodes.add(node);
return true;
}
});
Multimap<Integer, Node> nodesByLevel =
Multimaps.index(
nodes,
new Function<Node, Integer>() {
@Override
public Integer apply(Node input) {
return input.level;
}
});
for (Map.Entry<Integer, Collection<Node>> entry : nodesByLevel.asMap().entrySet()) {
builder.append("\tsubgraph level_" + entry.getKey() + " {\n").append("\t\trank = same;\n");
for (Node node : entry.getValue()) {
builder.append(
String.format(
"\t\t%s [label=\"[%s..%s]@%s\\n%s\", shape=rect, style=filled,color=%s];\n",
idFor(node),
node.getLowerBound(),
node.getUpperBound(),
node.level,
node.weightedCount,
node.weightedCount > 0 ? "salmon2" : "white"));
}
builder.append("\t}\n");
}
for (Node node : nodes) {
if (node.left != null) {
builder.append(format("\t%s -> %s;\n", idFor(node), idFor(node.left)));
}
if (node.right != null) {
builder.append(format("\t%s -> %s;\n", idFor(node), idFor(node.right)));
}
}
builder.append("}\n");
return builder.toString();
}
