public void Tag(Sentence sentence, TagOptions options)
{
// need training to generate model
if(_contextMapping == null)
{
var corpus = new CoNLLReader().Read(new ReaderOptions
{
DataDir = Path.Combine(options.CorpusDir, "CoNLL"),
FileName = "conll2000_chunking_train.txt"
});
Train(corpus, options);
}
Fill(sentence, options);
for (int pos = options.NGram - 1; pos < sentence.Words.Count; pos++)
{
sentence.Words[pos].Pos = _contextMapping.FirstOrDefault(x => x.Context == GetContext(pos, sentence.Words, options))?.Tag;
// set default tag
if(sentence.Words[pos].Pos == null)
{
sentence.Words[pos].Pos = options.Tag;
}
}
for(int pos = 0; pos < options.NGram - 1; pos++)
{
sentence.Words.RemoveAt(0);
}
}
public void Train(List<Sentence> sentences, TagOptions options)
{
var cache = new List<NGramFreq>();
for (int idx = 0; idx < sentences.Count; idx++)
{
var sent = sentences[idx];
Fill(sent, options);
for (int pos = options.NGram - 1; pos < sent.Words.Count; pos++)
{
var freq = new NGramFreq
{
Context = GetContext(pos, sent.Words, options),
Tag = sent.Words[pos].Pos,
Count = 1
};
cache.Add(freq);
}
}
_contextMapping = (from c in cache
group c by new { c.Context, c.Tag } into g
select new NGramFreq
{
Context = g.Key.Context,
Tag = g.Key.Tag,
Count = g.Count()
}).OrderByDescending(x => x.Count)
.ToList();
}
private void Fill(Sentence sent, TagOptions options)
{
for (int ngram = 1; ngram < options.NGram; ngram++)
{
sent.Words.Insert(0, new Token { Text = "NIL", Pos = options.Tag, Start = (ngram - 1) * 3 });
}
}
public void Tag(Sentence sentence, TagOptions options)
{
// need training to generate model
if (_contextMapping == null)
{
Train(options.Corpus, options);
}
Fill(sentence, options);
for (int pos = options.NGram - 1; pos < sentence.Words.Count; pos++)
{
sentence.Words[pos].Pos = _contextMapping.FirstOrDefault(x => x.Context == GetContext(pos, sentence.Words, options))?.Tag;
// set default tag
if (sentence.Words[pos].Pos == null)
{
sentence.Words[pos].Pos = options.Tag;
}
}
for (int pos = 0; pos < options.NGram - 1; pos++)
{
sentence.Words.RemoveAt(0);
}
}
private string GetContext(int pos, List<Token> words, TagOptions options)
{
string context = words[pos].Text;
for (int ngram = options.NGram - 1; ngram > 0; ngram--)
{
context = words[pos - ngram].Pos + " " + context;
}
return context;
}
public TaggerFactory(TagOptions options, SupportedLanguage lang)
{
_lang = lang;
_options = options;
_tagger = new ITag();
}
public void Train(List <Sentence> sentences, TagOptions options)
{
}
public void Tag(Sentence sentence, TagOptions options)
{
}