edu.berkeley.nlp.lm

Class ContextEncodedProbBackoffLm<W>

java.lang.Object

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

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

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

Type Parameters:

W -

All Implemented Interfaces:

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

public class ContextEncodedProbBackoffLm<W>
extends AbstractContextEncodedNgramLanguageModel<W>
implements ContextEncodedNgramLanguageModel<W>, java.io.Serializable

Language model implementation which uses Kneser-Ney style backoff computation.

Author:

adampauls

See Also:

Serialized Form

Nested Class Summary

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

ContextEncodedNgramLanguageModel.DefaultImplementations, ContextEncodedNgramLanguageModel.LmContextInfo

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
ContextEncodedProbBackoffLm(int lmOrder, WordIndexer<W> wordIndexer, ContextEncodedNgramMap<ProbBackoffPair> map, ConfigOptions opts)

Method Summary

Modifier and Type	Method and Description
float	getLogProb(long contextOffset, int contextOrder, int word, ContextEncodedNgramLanguageModel.LmContextInfo outputContext) Get the score for an n-gram, and also get the context offset of the n-gram's suffix.
int[]	getNgramForOffset(long contextOffset, int contextOrder, int word) Gets the n-gram referred to by a context-encoding.
NgramMap<ProbBackoffPair>	getNgramMap()
ContextEncodedNgramLanguageModel.LmContextInfo	getOffsetForNgram(int[] ngram, int startPos, int endPos) Gets the offset which refers to an n-gram.

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

getLogProb, scoreSentence

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, getLogProb, getWordIndexer, scoreSentence, setOovWordLogProb

Constructor Detail

ContextEncodedProbBackoffLm

public ContextEncodedProbBackoffLm(int lmOrder,
                                   WordIndexer<W> wordIndexer,
                                   ContextEncodedNgramMap<ProbBackoffPair> map,
                                   ConfigOptions opts)

Method Detail

getLogProb

public float getLogProb(long contextOffset,
                        int contextOrder,
                        int word,
                        ContextEncodedNgramLanguageModel.LmContextInfo outputContext)

Description copied from interface: ContextEncodedNgramLanguageModel

Get the score for an n-gram, and also get the context offset of the n-gram's suffix.

Specified by:

getLogProb in interface ContextEncodedNgramLanguageModel<W>

Specified by:

getLogProb in class AbstractContextEncodedNgramLanguageModel<W>

Parameters:

contextOffset - Offset of context (prefix) of an n-gram

contextOrder - The (0-based) length of context (i.e. order == 0 iff context refers to a unigram).

word - Last word of the n-gram

outputContext - Offset of the suffix of the input n-gram. If the parameter is null it will be ignored. This can be passed to future queries for efficient access.

Returns:

getOffsetForNgram

public ContextEncodedNgramLanguageModel.LmContextInfo getOffsetForNgram(int[] ngram,
                                                                        int startPos,
                                                                        int endPos)

Description copied from interface: ContextEncodedNgramLanguageModel

Gets the offset which refers to an n-gram. If the n-gram is not in the model, then it returns the shortest suffix of the n-gram which is. This operation is not necessarily fast.

Specified by:

getOffsetForNgram in interface ContextEncodedNgramLanguageModel<W>

Specified by:

getOffsetForNgram in class AbstractContextEncodedNgramLanguageModel<W>

getNgramForOffset

public int[] getNgramForOffset(long contextOffset,
                               int contextOrder,
                               int word)

Description copied from interface: ContextEncodedNgramLanguageModel

Gets the n-gram referred to by a context-encoding. This operation is not necessarily fast.

Specified by:

getNgramForOffset in interface ContextEncodedNgramLanguageModel<W>

Specified by:

getNgramForOffset in class AbstractContextEncodedNgramLanguageModel<W>

getNgramMap

public NgramMap<ProbBackoffPair> getNgramMap()