Package edu.berkeley.nlp.lm.cache

Class ArrayEncodedCachingLmWrapper<W>

java.lang.Object

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

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

edu.berkeley.nlp.lm.cache.ArrayEncodedCachingLmWrapper<W>

Type Parameters:

W -

All Implemented Interfaces:

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

public class ArrayEncodedCachingLmWrapper<W>
extends AbstractArrayEncodedNgramLanguageModel<W>

This class wraps ArrayEncodedNgramLanguageModel with a cache.

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

Method Summary

Modifier and Type	Method	Description
float	getLogProb(int[] ngram, int startPos, int endPos)	Calculate language model score of an n-gram.
static <W> ArrayEncodedCachingLmWrapper<W>	wrapWithCacheNotThreadSafe(ArrayEncodedNgramLanguageModel<W> lm)	To use this wrapper in a multithreaded environment, you should create one wrapper per thread.
static <W> ArrayEncodedCachingLmWrapper<W>	wrapWithCacheNotThreadSafe(ArrayEncodedNgramLanguageModel<W> lm, int cacheBits)
static <W> ArrayEncodedCachingLmWrapper<W>	wrapWithCacheThreadSafe(ArrayEncodedNgramLanguageModel<W> lm)	This type of caching is threadsafe and (internally) maintains a separate cache for each thread that calls it.
static <W> ArrayEncodedCachingLmWrapper<W>	wrapWithCacheThreadSafe(ArrayEncodedNgramLanguageModel<W> lm, int cacheBits)

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

getLogProb, 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, getWordIndexer, setOovWordLogProb

Method Detail

wrapWithCacheNotThreadSafe

public static <W> ArrayEncodedCachingLmWrapper<W> wrapWithCacheNotThreadSafe(ArrayEncodedNgramLanguageModel<W> lm)

To use this wrapper in a multithreaded environment, you should create one wrapper per thread.

Type Parameters:

T -

Parameters:

lm -

Returns:

wrapWithCacheNotThreadSafe

public static <W> ArrayEncodedCachingLmWrapper<W> wrapWithCacheNotThreadSafe(ArrayEncodedNgramLanguageModel<W> lm,
                                                                             int cacheBits)

wrapWithCacheThreadSafe

public static <W> ArrayEncodedCachingLmWrapper<W> wrapWithCacheThreadSafe(ArrayEncodedNgramLanguageModel<W> lm)

This type of caching is threadsafe and (internally) maintains a separate cache for each thread that calls it. Note each thread has its own cache, so if you have lots of threads, memory usage could be substantial.

Type Parameters:

W -

Parameters:

lm -

Returns:

wrapWithCacheThreadSafe

public static <W> ArrayEncodedCachingLmWrapper<W> wrapWithCacheThreadSafe(ArrayEncodedNgramLanguageModel<W> lm,
                                                                          int cacheBits)

getLogProb

public 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>

Specified by:

getLogProb in class AbstractArrayEncodedNgramLanguageModel<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: