public T Compute <T>(IDPAlgorithm <T> algorithm, TDNode parent)
{
VertexSubset.ClearLookup();
// Note: through preprocessing, certain subtrees might have become empty. Do not consider.
IEnumerable <TDNode> children = Adj.Where((n) => n != parent && n.Subtree.Any());
if (children.Count() == 0)
{
return(algorithm.IntroduceEdges(algorithm.Introduce(this, Bag, algorithm.Leaf(ParentDecomposition.Width)), introduceEdges));
}
if (children.Count() == 1)
{
TDNode child = children.First();
Vertex[] toForget = child.Bag.Where((v) => !this.BagContains(v)).OrderBy((v) => v.Adj.Where((w) => BagContains(w.To)).Count()).Reverse().ToArray();
Vertex[] toIntroduce = this.Bag.Where((v) => !child.BagContains(v)).ToArray();
if (toIntroduce.Length > 0)
{
return(algorithm.IntroduceEdges(algorithm.Introduce(this, toIntroduce, child.Compute(algorithm, this)), introduceEdges));
}
if (toForget.Length > 0)
{
return(algorithm.IntroduceEdges(algorithm.Forget(this, toForget, child.Compute(algorithm, this)), introduceEdges));
}
// No change?
return(algorithm.IntroduceEdges(child.Compute(algorithm, this), introduceEdges));
}
if (children.Count() > 2)
{
throw new Exception("TD not preprocessed!");
}
TDNode left = children.ElementAt(0), right = children.ElementAt(1);
return(algorithm.IntroduceEdges(algorithm.Join(this, IntroduceIfNecessary(algorithm, left, left.Compute(algorithm, this)), IntroduceIfNecessary(algorithm, right, right.Compute(algorithm, this))), introduceEdges));
}
public T Compute <T>(IDPAlgorithm <T> algorithm)
{
return(Root.Compute(algorithm, null));
}
