private float GetAvailableBackoff(WordSequence wordSequence)
{
float backoff = 0.0f;
int wordsNum = wordSequence.Size;
int wordId = unigramIDMap.Get(wordSequence.GetWord(wordsNum - 2));
TrieRange range = new TrieRange(unigrams[wordId].next, unigrams[wordId + 1].next);
if (curDepth == 1)
{
backoff += unigrams[wordId].backoff;
}
int sequenceIdx, orderMinusTwo;
for (sequenceIdx = wordsNum - 3, orderMinusTwo = 0; sequenceIdx >= 0; sequenceIdx--, orderMinusTwo++)
{
int tmpWordId = unigramIDMap.Get(wordSequence.GetWord(sequenceIdx));
float tmpBackoff = trie.readNgramBackoff(tmpWordId, orderMinusTwo, range, quant);
if (!range.getFound())
{
break;
}
backoff += tmpBackoff;
if (!range.isSearchable())
{
break;
}
}
return(backoff);
}
private float GetAvailableProb(WordSequence wordSequence, TrieRange range, float prob)
{
if (!range.isSearchable())
{
return(prob);
}
for (int reverseOrderMinusTwo = wordSequence.Size - 2; reverseOrderMinusTwo >= 0; reverseOrderMinusTwo--)
{
int orderMinusTwo = wordSequence.Size - 2 - reverseOrderMinusTwo;
if (orderMinusTwo + 1 == MaxDepth)
{
break;
}
int wordId = unigramIDMap.Get(wordSequence.GetWord(reverseOrderMinusTwo));
float updatedProb = trie.readNgramProb(wordId, orderMinusTwo, range, quant);
if (!range.getFound())
{
break;
}
prob = updatedProb;
curDepth++;
if (!range.isSearchable())
{
break;
}
}
return(prob);
}
internal void readNextRange(int ngramIdx, TrieRange range)
{
int offset = ngramIdx * totalBits;
offset += wordBits;
offset += getQuantBits();
range.begin = _parent.bitArr.readInt(memPtr, offset, nextMask);
offset += totalBits;
range.end = _parent.bitArr.readInt(memPtr, offset, nextMask);
}
private float GetProbabilityRaw(WordSequence wordSequence)
{
int wordsNum = wordSequence.Size;
int wordId = unigramIDMap.Get(wordSequence.GetWord(wordsNum - 1));
TrieRange range = new TrieRange(unigrams[wordId].next, unigrams[wordId + 1].next);
float prob = unigrams[wordId].prob;
curDepth = 1;
if (wordsNum == 1)
{
return(prob);
}
//find prob of ngrams of higher order if any
prob = GetAvailableProb(wordSequence, range, prob);
if (curDepth < wordsNum)
{
//use backoff for rest of ngram
prob += GetAvailableBackoff(wordSequence);
}
return(prob);
}
