internal History(PairsHolder pairs, Extractors extractors)
{
// this is the index of the first word of the sentence
//this is the index of the last word in the sentence - the dot
// this is the index of the current word
this.pairs = pairs;
this.extractors = extractors;
}
// This precomputes scores of local features (localScores).
protected internal virtual double[] GetHistories(string[] tags, History h)
{
bool rare = maxentTagger.IsRare(ExtractorFrames.cWord.Extract(h));
Extractors ex = maxentTagger.extractors;
Extractors exR = maxentTagger.extractorsRare;
string w = pairs.GetWord(h.current);
double[] lS;
double[] lcS;
lS = localScores[w];
if (lS == null)
{
lS = GetHistories(tags, h, ex.local, rare ? exR.local : null);
localScores[w] = lS;
}
else
{
if (lS.Length != tags.Length)
{
// This case can occur when a word was given a specific forced
// tag, and then later it shows up without the forced tag.
// TODO: if a word is given a forced tag, we should always get
// its features rather than use the cache, just in case the tag
// given is not the same tag as before
lS = GetHistories(tags, h, ex.local, rare ? exR.local : null);
if (tags.Length > 1)
{
localScores[w] = lS;
}
}
}
if ((lcS = localContextScores[h.current]) == null)
{
lcS = GetHistories(tags, h, ex.localContext, rare ? exR.localContext : null);
localContextScores[h.current] = lcS;
ArrayMath.PairwiseAddInPlace(lcS, lS);
}
double[] totalS = GetHistories(tags, h, ex.dynamic, rare ? exR.dynamic : null);
ArrayMath.PairwiseAddInPlace(totalS, lcS);
return(totalS);
}
internal History(int start, int end, int current, PairsHolder pairs, Extractors extractors)
{
this.pairs = pairs;
this.extractors = extractors;
Init(start, end, current);
}
