/**
* Finds or loads the NGram probability of the given NGram.
*
* @param wordSequence the NGram to load
* @return a NGramProbability of the given NGram
*/
private NGramProbability FindNGram(WordSequence wordSequence)
{
var numberWords = wordSequence.Size;
NGramProbability nGram = null;
var oldest = wordSequence.GetOldest();
var nGramBuffer = _loadedNGramBuffers[numberWords - 1].Get(oldest);
if (nGramBuffer == null)
{
nGramBuffer = GetNGramBuffer(oldest);
if (nGramBuffer != null)
{
_loadedNGramBuffers[numberWords - 1].Add(oldest, nGramBuffer);
}
}
if (nGramBuffer != null)
{
var nthWordID = GetWordID(wordSequence.GetWord(numberWords - 1));
nGram = nGramBuffer.FindNGram(nthWordID);
}
return(nGram);
}
/**
* /// Finds the NGram probabilities for the given nth word in a NGram.
*
* /// @param nthWordID the ID of the nth word
* /// @return the NGramProbability of the given nth word
*/
public override NGramProbability FindNGram(int nthWordID)
{
int mid, start = 0, end = NumberNGrams;
NGramProbability ngram = null;
while ((end - start) > 0)
{
mid = (start + end) / 2;
var midWordID = GetWordID(mid);
if (midWordID < nthWordID)
{
start = mid + 1;
}
else if (midWordID > nthWordID)
{
end = mid;
}
else
{
ngram = GetNGramProbability(mid);
break;
}
}
return(ngram);
}
/**
* Returns the index of the first NGram entry of the given N-1Gram
*
* @param nMinus1Gram the N-1Gram which first NGram entry we're looking for
* @param firstNMinus1GramEntry the index of the first N-1Gram entry of the
* N-1Gram in question
* @param n the order of the NGram
* @return the index of the first NGram entry of the given N-1Gram
*/
private int GetFirstNGramEntry(NGramProbability nMinus1Gram, int firstNMinus1GramEntry, int n)
{
var firstNGramEntry =
_ngramSegmentTable[n - 1][(firstNMinus1GramEntry + nMinus1Gram.WhichFollower) >> _loader.GetLogNGramSegmentSize()]
+ nMinus1Gram.FirstNPlus1GramEntry;
return(firstNGramEntry);
}
