private static void MergeIdenticalTransitions(List <Arc> identicalWords)
{
Collection <Arc> collection = null;
Arc arc = null;
foreach (Arc identicalWord in identicalWords)
{
if (arc != null && Arc.CompareIdenticalTransitions(arc, identicalWord) == 0)
{
identicalWord.Weight += arc.Weight;
arc.ClearTags();
if (collection == null)
{
collection = new Collection <Arc>();
}
collection.Add(arc);
}
arc = identicalWord;
}
if (collection != null)
{
foreach (Arc item in collection)
{
DeleteTransition(item);
}
}
}
/// <summary>
/// Description:
/// Merge identical transitions with identical content, StartState, and EndState.
///
/// Algorithm:
/// - LastArc = Arcs[0]
/// - For each Arc in Arcs[1-],
/// - If Arc is identical to LastArc,
/// - LastArc.Weight += Arc.Weight
/// - Delete Arc
/// - Else LastArc = Arc
///
/// Moving SemanticTag:
/// - Identical transitions have identical semantic tags. Currently impossible to have identical
/// non-null tags.
/// - MoveSemanticTagReferences(DuplicateArc, CommonArc)
/// </summary>
private static void MergeIdenticalTransitions(List <Arc> identicalWords)
{
Collection <Arc> arcsToDelete = null;
Arc refArc = null;
foreach (Arc arc in identicalWords)
{
if (refArc != null && Arc.CompareIdenticalTransitions(refArc, arc) == 0)
{
// Identical transition
arc.Weight += refArc.Weight;
refArc.ClearTags();
if (arcsToDelete == null)
{
// delay the creation of the collection as this operation in infrequent.
arcsToDelete = new Collection <Arc>();
}
arcsToDelete.Add(refArc);
}
refArc = arc;
}
if (arcsToDelete != null)
{
foreach (Arc arc in arcsToDelete)
{
// arc will become an orphan
DeleteTransition(arc);
}
}
}
