edu.cmu.sphinx.linguist.language.ngram.trie

Class NgramTrie

java.lang.Object

edu.cmu.sphinx.linguist.language.ngram.trie.NgramTrie

public class NgramTrie
extends java.lang.Object

Trie structure that contains ngrams of order 2+ in reversed order. Ngrams are stored in bit array for space efficiency.

Constructor Summary

Constructors

Constructor and Description
NgramTrie(int[] counts, int quantProbBoLen, int quantProbLen)

Method Summary

Modifier and Type	Method and Description
byte[]	getMem() Getter for allocated byte array to which trie is mapped
float	readNgramBackoff(int wordId, int orderMinusTwo, NgramTrieModel.TrieRange range, NgramTrieQuant quant) Finds ngram of cerain order in specified range and reads it's backoff.
float	readNgramProb(int wordId, int orderMinusTwo, NgramTrieModel.TrieRange range, NgramTrieQuant quant) Finds ngram of cerain order in specified range and reads it's probability.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NgramTrie

public NgramTrie(int[] counts,
                 int quantProbBoLen,
                 int quantProbLen)

Method Detail

getMem

public byte[] getMem()

Getter for allocated byte array to which trie is mapped

Returns:

byte[] with ngram trie

readNgramBackoff

public float readNgramBackoff(int wordId,
                              int orderMinusTwo,
                              NgramTrieModel.TrieRange range,
                              NgramTrieQuant quant)

Finds ngram of cerain order in specified range and reads it's backoff. Range contains ngram successors after function execution. If ngram is not found, range will be invalid.

Parameters:

wordId - - word id to look for

orderMinusTwo - - order of ngram minus two

range - - range to look in, contains ngram successors after function execution

quant - - quantation object to decode compressed backoff stored in trie

Returns:

backoff of ngram

readNgramProb

public float readNgramProb(int wordId,
                           int orderMinusTwo,
                           NgramTrieModel.TrieRange range,
                           NgramTrieQuant quant)

Finds ngram of cerain order in specified range and reads it's probability. Range contains ngram successors after function execution. If ngram is not found, range will be invalid.

Parameters:

wordId - - word id to look for

orderMinusTwo - - order of ngram minus two

range - - range to look in, contains ngram successors after function execution

quant - - quantation object to decode compressed probability stored in trie

Returns:

probability of ngram