Package edu.berkeley.nlp.lm

Class AbstractContextEncodedNgramLanguageModel<W>

java.lang.Object

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

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

All Implemented Interfaces:

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

Direct Known Subclasses:

ContextEncodedCachingLmWrapper, ContextEncodedProbBackoffLm

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

Default implementation of all ContextEncodedNgramLanguageModel functionality except getLogProb(long, int, int, LmContextInfo), {@link #getOffsetForNgram(int[], int, int), and {

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	Description
AbstractContextEncodedNgramLanguageModel(int lmOrder, WordIndexer<W> wordIndexer, float oovWordLogProb)

Method Summary

Modifier and Type	Method	Description
abstract 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.
float	getLogProb(java.util.List<W> phrase)	Scores an n-gram.
abstract int[]	getNgramForOffset(long contextOffset, int contextOrder, int word)	Gets the n-gram referred to by a context-encoding.
abstract ContextEncodedNgramLanguageModel.LmContextInfo	getOffsetForNgram(int[] ngram, int startPos, int endPos)	Gets the offset which refers to 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

AbstractContextEncodedNgramLanguageModel

public AbstractContextEncodedNgramLanguageModel(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 abstract 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>

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 abstract 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>

getNgramForOffset

public abstract 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>