private int ComputeCosts(List <AlignedSubstring> path, AlignedSubstring candidate)
{
if (candidate == null)
{
throw new ArgumentNullException("candidate");
}
// currently we simply compute the distance of the candidate to the nearest path element.
// We may later compute "contributions" to existing token ranges (i.e. how well a token is covered)
int minDist = -1;
foreach (AlignedSubstring alg in path)
{
int srcDist = 0;
int trgDist = 0;
if (alg.Source.Start < candidate.Source.Start)
{
srcDist = candidate.Source.Start - alg.Source.Start - alg.Source.Length;
}
else
{
srcDist = alg.Source.Start - candidate.Source.Start - candidate.Source.Length;
}
if (alg.Target.Start < candidate.Target.Start)
{
trgDist = candidate.Target.Start - alg.Target.Start - alg.Target.Length;
}
else
{
trgDist = alg.Target.Start - candidate.Target.Start - candidate.Target.Length;
}
System.Diagnostics.Debug.Assert(srcDist >= 0);
System.Diagnostics.Debug.Assert(trgDist >= 0);
int dist = Math.Max(srcDist, trgDist);
if (minDist < 0 || dist < minDist)
{
minDist = dist;
}
}
System.Diagnostics.Debug.Assert(minDist >= 0);
return(minDist);
}
public AlignedSubstring PickExtension(List <AlignedSubstring> path,
List <AlignedSubstring> candidates)
{
if (path == null)
{
throw new ArgumentNullException("path");
}
if (candidates == null)
{
throw new ArgumentNullException("candidates");
}
if (candidates.Count == 0)
{
return(null);
}
if (candidates.Count == 1)
{
return(candidates[0]);
}
// if we don't yet have a path, pick any candidate (can't attach)
if (path.Count == 0)
{
return(candidates[0]);
}
AlignedSubstring result = null;
int minCost = 0;
foreach (AlignedSubstring cand in candidates)
{
int cost = ComputeCosts(path, cand);
if (result == null || cost < minCost)
{
minCost = cost;
result = cand;
}
}
return(result);
}
private static TermFinderResult FindTermsCharBased(Core.Segment searchSegment,
Core.Segment textSegment, bool expectContinuousMatch)
{
// This should only be used for far-east languages
// these ranges capture the mapping from a character position in the plain text arrays
// to a segment position (run/position pairs)
List <Core.SegmentPosition> searchSegmentPositions;
List <Core.SegmentPosition> textSegmentPositions;
string searchPlain = searchSegment.ToPlain(true, true, out searchSegmentPositions);
string textPlain = textSegment.ToPlain(true, true, out textSegmentPositions);
if (searchPlain.Length == 0)
{
// TODO may need to look into what may cause such an issue:
System.Diagnostics.Debug.Assert(false, "Let Oli know and provide test data");
return(null);
}
char[] searchPlainArray = searchPlain.ToCharArray();
char[] textPlainArray = textPlain.ToCharArray();
int searchPlainLength = searchPlain.Length;
int textPlainLength = textPlain.Length;
System.Diagnostics.Debug.Assert(searchPlainLength == searchPlainArray.Length);
System.Diagnostics.Debug.Assert(textPlainLength == textPlainArray.Length);
List <AlignedSubstring> lcs = null;
SubstringAlignmentDisambiguator picker
= new SubstringAlignmentDisambiguator();
lcs = SequenceAlignmentComputer <char> .ComputeCoverage(searchPlainArray,
textPlainArray, new CharSubstringScoreProvider(), picker);
if (lcs == null || lcs.Count == 0)
{
return(null);
}
TermFinderResult result = new TermFinderResult();
result.MatchingRanges = new List <Sdl.LanguagePlatform.Core.SegmentRange>();
List <Core.SegmentPosition> textPositions = new List <Core.SegmentPosition>();
for (int subIdx = 0; subIdx < lcs.Count; ++subIdx)
{
AlignedSubstring sub = lcs[subIdx];
if (sub.Source.Length != sub.Target.Length)
{
// NOTE LCSubseq instead of Substring? Check scorer if this fires
System.Diagnostics.Debug.Assert(false, "Not supported - let Oli know and provide test data");
return(null);
}
for (int p = 0; p < sub.Source.Length; ++p)
{
textPositions.Add(textSegmentPositions[sub.Target.Start + p]);
}
}
if (textPositions.Count == 0)
{
return(null);
}
// covered ranges in the text segment:
result.MatchingRanges = SortAndMelt(textPositions);
// TODO this does not capture adjacency
float baseScore = (float)textPositions.Count / (float)searchPlainLength;
#if DEBUG
bool ok = VerifyRanges(result.MatchingRanges,
textSegment);
if (!ok)
{
System.Diagnostics.Debug.Assert(false, "Range verification failed");
}
#endif
result.Score = (int)(100.0f * baseScore);
if (result.Score < 0)
{
result.Score = 0;
}
else if (result.Score > 100)
{
result.Score = 100;
}
return(result);
}
/// <summary>
/// Computes the longest local alignment coverage of the two sequences used to
/// initialize this instance. Unlike <see cref="M:Compute()"/>, you can specify
/// positions in the sequences up to which to compute the alignment.
/// </summary>
/// <param name="uptoSource">The maximum index to cover in the source sequence (exclusive)</param>
/// <param name="uptoTarget">The maximum index to cover in the target sequence (exclusive)</param>
public List <AlignedSubstring> Compute(int uptoSource, int uptoTarget)
{
if (uptoSource <= 0 || uptoSource > _Source.Count)
{
throw new ArgumentOutOfRangeException("uptoSource");
}
if (uptoTarget <= 0 || uptoTarget > _Target.Count)
{
throw new ArgumentOutOfRangeException("uptoTarget");
}
List <AlignedSubstring> result = new List <AlignedSubstring>();
int globalMax = 0;
List <Pair <int> > maxima = new List <Pair <int> >();
if (_AlignmentScores == null)
{
_AlignmentScores = ComputeScores(_Source, _Target, _Scorer);
}
bool maySkip = _Scorer.MaySkip;
if (maySkip)
{
if (_SourceSkipScores == null || _TargetSkipScores == null)
{
ComputeSkipScoreCaches();
}
}
bool computeCoverage = (_MaxItems != 1);
if (_Table == null)
{
_Table = new Cell[_Source.Count + 1, _Target.Count + 1];
if (!computeCoverage)
{
ComputeFullTable(maySkip);
}
}
bool[,] blocked = null;
if (computeCoverage)
{
blocked = new bool[_Source.Count + 1, _Target.Count + 1];
}
do
{
if (computeCoverage)
{
ComputeMaximaForCoverage(maxima, ref globalMax, uptoSource, uptoTarget, maySkip, blocked);
}
else
{
ComputeMaximaForLCS(maxima, ref globalMax, uptoSource, uptoTarget);
}
if (maxima.Count > 0)
{
List <AlignedSubstring> extensionCandiates = new List <AlignedSubstring>();
foreach (Pair <int> max in maxima)
{
// read out the transition
int iStart = max.Left;
int jStart = max.Right;
int len = 0;
while (_Table[iStart, jStart].Score > 0)
{
Cell c = _Table[iStart, jStart];
if (c.Op == Operation.Align)
{
// not a skip
len++;
}
iStart = c.BackI;
jStart = c.BackJ;
}
// aligned sequence is s1[iStart, globalMaxI[, s2[jStart, globalMaxJ[
AlignedSubstring lsa
= new AlignedSubstring(iStart, max.Left - iStart, jStart, max.Right - jStart, globalMax, len);
if (len >= _MinLength)
{
extensionCandiates.Add(lsa);
}
}
if (extensionCandiates.Count == 0)
{
// if we have maxima, but no extension candidates, they got dropped by the minLength
// requirement. To avoid infinite loops, we must stop further iteration and set the
// break criterion.
maxima.Clear();
}
else
{
AlignedSubstring winner = null;
if (_Picker == null)
{
// if we have no disambiguator, pick the first candidate
// TODO other defaults may be better (longest, etc.)
winner = extensionCandiates[0];
}
else
{
winner = _Picker.PickExtension(result, extensionCandiates);
}
if (winner == null)
{
break;
}
else
{
if (blocked != null)
{
// mark the covered ranges as "taken" so that we don't get overlaps
for (int iStart = 1; iStart <= uptoSource; ++iStart)
{
for (int jStart = 1; jStart <= uptoTarget; ++jStart)
{
if ((iStart > winner.Source.Start && iStart <= winner.Source.Start + winner.Source.Length) ||
(jStart > winner.Target.Start && jStart <= winner.Target.Start + winner.Target.Length))
{
blocked[iStart, jStart] = true;
}
}
}
}
result.Add(winner);
}
}
}
} while (maxima.Count > 0 && (_MaxItems == 0 || result.Count < _MaxItems));
return(result);
}