edu.berkeley.nlp.lm

Class AbstractArrayEncodedNgramLanguageModel<W>

java.lang.Object

edu.berkeley.nlp.lm.AbstractNgramLanguageModel<W>

edu.berkeley.nlp.lm.AbstractArrayEncodedNgramLanguageModel<W>

Type Parameters:

W -

All Implemented Interfaces:

ArrayEncodedNgramLanguageModel<W>, NgramLanguageModel<W>, java.io.Serializable

Direct Known Subclasses:

ArrayEncodedCachingLmWrapper, ArrayEncodedProbBackoffLm, StupidBackoffLm

public abstract class AbstractArrayEncodedNgramLanguageModel<W>
extends AbstractNgramLanguageModel<W>
implements ArrayEncodedNgramLanguageModel<W>, java.io.Serializable

Default implementation of all NGramLanguageModel functionality except getLogProb(int[], int, int).

Author:

adampauls

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface edu.berkeley.nlp.lm.ArrayEncodedNgramLanguageModel

ArrayEncodedNgramLanguageModel.DefaultImplementations

Nested classes/interfaces inherited from interface edu.berkeley.nlp.lm.NgramLanguageModel

NgramLanguageModel.StaticMethods

Field Summary

Fields inherited from class edu.berkeley.nlp.lm.AbstractNgramLanguageModel

lmOrder, oovWordLogProb

Constructor Summary

Constructors

Constructor and Description
AbstractArrayEncodedNgramLanguageModel(int lmOrder, WordIndexer<W> wordIndexer, float oovWordLogProb)

Method Summary

Modifier and Type	Method and Description
float	getLogProb(int[] ngram) Equivalent to getLogProb(ngram, 0, ngram.length)
abstract float	getLogProb(int[] ngram, int startPos, int endPos) Calculate language model score of an n-gram.
float	getLogProb(java.util.List<W> phrase) Scores an n-gram.
float	scoreSentence(java.util.List<W> sentence) Scores a complete sentence, taking appropriate care with the start- and end-of-sentence symbols.

Methods inherited from class edu.berkeley.nlp.lm.AbstractNgramLanguageModel

getLmOrder, getWordIndexer, setOovWordLogProb

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.berkeley.nlp.lm.NgramLanguageModel

getLmOrder, getWordIndexer, setOovWordLogProb

Constructor Detail

AbstractArrayEncodedNgramLanguageModel

public AbstractArrayEncodedNgramLanguageModel(int lmOrder,
                                              WordIndexer<W> wordIndexer,
                                              float oovWordLogProb)

Method Detail

scoreSentence

public float scoreSentence(java.util.List<W> sentence)

Description copied from interface: NgramLanguageModel

Scores a complete sentence, taking appropriate care with the start- and end-of-sentence symbols. This is a convenience method and will generally be inefficient.

Specified by:

scoreSentence in interface NgramLanguageModel<W>

Returns:

getLogProb

public float getLogProb(java.util.List<W> phrase)

Description copied from interface: NgramLanguageModel

Scores an n-gram. This is a convenience method and will generally be relatively inefficient. More efficient versions are available in ArrayEncodedNgramLanguageModel.getLogProb(int[], int, int) and ContextEncodedNgramLanguageModel.getLogProb(long, int, int, edu.berkeley.nlp.lm.ContextEncodedNgramLanguageModel.LmContextInfo) .

Specified by:

getLogProb in interface NgramLanguageModel<W>

getLogProb

public float getLogProb(int[] ngram)

Description copied from interface: ArrayEncodedNgramLanguageModel

Equivalent to getLogProb(ngram, 0, ngram.length)

Specified by:

getLogProb in interface ArrayEncodedNgramLanguageModel<W>

See Also:

ArrayEncodedNgramLanguageModel.getLogProb(int[], int, int)

getLogProb

public abstract float getLogProb(int[] ngram,
                                 int startPos,
                                 int endPos)

Description copied from interface: ArrayEncodedNgramLanguageModel

Calculate language model score of an n-gram. Warning: if you pass in an n-gram of length greater than getLmOrder(), this call will silently ignore the extra words of context. In other words, if you pass in a 5-gram (endPos-startPos == 5) to a 3-gram model, it will only score the words from startPos + 2 to endPos.

Specified by:

getLogProb in interface ArrayEncodedNgramLanguageModel<W>

Parameters:

ngram - array of words in integer representation

startPos - start of the portion of the array to be read

endPos - end of the portion of the array to be read.

Returns: