/// <summary>
/// Returns the trees (and scores) corresponding to the
/// k-best derivations of the sentence.
/// </summary>
/// <remarks>
/// Returns the trees (and scores) corresponding to the
/// k-best derivations of the sentence. This cannot be
/// a Counter because frequently there will be multiple
/// derivations which lead to the same parse tree.
/// </remarks>
/// <param name="k">The number of best parses to return</param>
/// <returns>The list of trees with their scores (log prob).</returns>
public virtual IList <ScoredObject <Tree> > GetKBestPCFGParses(int k)
{
if (pparser == null)
{
return(null);
}
IList <ScoredObject <Tree> > binaryTrees = pparser.GetKBestParses(k);
if (binaryTrees == null)
{
return(null);
}
IList <ScoredObject <Tree> > trees = new List <ScoredObject <Tree> >(k);
foreach (ScoredObject <Tree> p in binaryTrees)
{
Tree t = debinarizer.TransformTree(p.Object());
t = subcategoryStripper.TransformTree(t);
RestoreOriginalWords(t);
trees.Add(new ScoredObject <Tree>(t, p.Score()));
}
return(trees);
}
/// <summary>Parse a Sentence.</summary>
/// <remarks>
/// Parse a Sentence. It is assumed that when this is called, the pparser
/// has already been called to parse the sentence.
/// </remarks>
/// <param name="words">The list of words to parse.</param>
/// <returns>true iff it could be parsed</returns>
public virtual bool Parse <_T0>(IList <_T0> words)
where _T0 : IHasWord
{
nGoodTrees.Clear();
int numParsesToConsider = numToFind * op.testOptions.fastFactoredCandidateMultiplier + op.testOptions.fastFactoredCandidateAddend;
if (pparser.HasParse())
{
IList <ScoredObject <Tree> > pcfgBest = pparser.GetKBestParses(numParsesToConsider);
Beam <ScoredObject <Tree> > goodParses = new Beam <ScoredObject <Tree> >(numToFind);
foreach (ScoredObject <Tree> candidate in pcfgBest)
{
if (Thread.Interrupted())
{
throw new RuntimeInterruptedException();
}
double depScore = DepScoreTree(candidate.Object());
ScoredObject <Tree> x = new ScoredObject <Tree>(candidate.Object(), candidate.Score() + depScore);
goodParses.Add(x);
}
nGoodTrees = goodParses.AsSortedList();
}
return(!nGoodTrees.IsEmpty());
}