/// <summary>
/// Returns the span (number of spanned tokens) of the tag.
/// </summary>
private static int GetTagSpan(PairedTag pt)
{
int s = pt.End - pt.Start - 1;
System.Diagnostics.Debug.Assert(s >= 0);
return(s);
}
public TagAssociation(PairedTag sourceTag, PairedTag targetTag,
Core.EditDistance.EditOperation op)
{
SourceTag = sourceTag;
TargetTag = targetTag;
Operation = op;
}
/// <summary>
/// <see cref="M:System.Object.Equals(object)"/>
/// </summary>
/// <param name="obj">The object to compare with the current object.</param>
/// <returns>true if the specified object is equal to the current object;
/// otherwise, false.
/// </returns>
public override bool Equals(object obj)
{
if (obj == null)
{
return(false);
}
if (obj.GetType() != this.GetType())
{
return(false);
}
PairedTag other = obj as PairedTag;
return(other.Start == this.Start && other.End == this.End && other.Anchor == this.Anchor);
}
public void Add(PairedTag srcTag, PairedTag trgTag,
Core.EditDistance.EditOperation op)
{
System.Diagnostics.Debug.Assert(srcTag != null || trgTag != null);
if (op == Core.EditDistance.EditOperation.Undefined)
{
if (srcTag == null)
{
op = Core.EditDistance.EditOperation.Insert;
}
else if (trgTag == null)
{
op = Core.EditDistance.EditOperation.Delete;
}
else
{
op = Core.EditDistance.EditOperation.Change;
}
}
int idx = _Associations.Count;
_Associations.Add(new TagAssociation(srcTag, trgTag, op));
if (srcTag != null)
{
System.Diagnostics.Debug.Assert(srcTag.Start < srcTag.End);
_SrcPositionIdx.Add(srcTag.Start, idx);
_SrcPositionIdx.Add(srcTag.End, idx);
}
if (trgTag != null)
{
System.Diagnostics.Debug.Assert(trgTag.Start < trgTag.End);
_TrgPositionIdx.Add(trgTag.Start, idx);
_TrgPositionIdx.Add(trgTag.End, idx);
}
}
public void Add(PairedTag srcTag, PairedTag trgTag)
{
Add(srcTag, trgTag, Core.EditDistance.EditOperation.Undefined);
}
private static int[,] ComputeTagAssociationScores(SimilarityMatrix similarityMatrix,
TagPairs srcPairedTags,
TagPairs trgPairedTags,
bool useEndPositions)
{
// this should pretty much result in first-come first-serve alignment, but we hopefully
// get better associations for nested tags
// foreach src tag, compute LCS to each target tag
int[,] lcsScores = new int[srcPairedTags.Count, trgPairedTags.Count];
List <int> sourceTokenPositions = new List <int>();
List <int> targetTokenPositions = new List <int>();
TokenIndexLCSScoreProvider scorer
= new TokenIndexLCSScoreProvider(similarityMatrix, 0.75, true);
for (int p = 0; p < similarityMatrix.SourceTokens.Count; ++p)
{
sourceTokenPositions.Add(p);
}
for (int p = 0; p < similarityMatrix.TargetTokens.Count; ++p)
{
targetTokenPositions.Add(p);
}
SequenceAlignmentComputer <int> aligner
= new SequenceAlignmentComputer <int>(sourceTokenPositions,
targetTokenPositions, scorer, null, 1, 1);
int uptoSource;
int uptoTarget;
for (int srcTag = srcPairedTags.Count - 1; srcTag >= 0; --srcTag)
{
PairedTag sPt = srcPairedTags[srcTag];
uptoSource = (useEndPositions ? sPt.End : sPt.Start);
for (int trgTag = trgPairedTags.Count - 1; trgTag >= 0; --trgTag)
{
PairedTag tPt = trgPairedTags[trgTag];
uptoTarget = (useEndPositions ? tPt.End : tPt.Start);
List <AlignedSubstring> result
= aligner.Compute(uptoSource, uptoTarget);
if (result != null && result.Count > 0)
{
System.Diagnostics.Debug.Assert(result.Count == 1);
// the result is the common subsequence length minus items which were deleted or inserted
int score = result[0].Score
- (uptoSource - result[0].Score)
- (uptoTarget - result[0].Score);
// penalize large differences in the spanned width, but not if
// we include the end positions in the LCS
int malus;
if (useEndPositions)
{
malus = 0;
}
else
{
int srcSpan = GetTagSpan(sPt);
int trgSpan = GetTagSpan(tPt);
malus = Math.Abs(srcSpan - trgSpan) / 2;
}
lcsScores[srcTag, trgTag] = score - malus;
}
}
}
return(lcsScores);
}
public TagAssociation(PairedTag sourceTag, PairedTag targetTag)
: this(sourceTag, targetTag, Core.EditDistance.EditOperation.Undefined)
{
}