edu.cmu.sphinx.linguist.language.ngram

Class SimpleNGramModel

java.lang.Object

edu.cmu.sphinx.linguist.language.ngram.SimpleNGramModel

All Implemented Interfaces:

LanguageModel, Configurable

public class SimpleNGramModel
extends java.lang.Object
implements LanguageModel

An ASCII ARPA language model loader. This loader makes no attempt to optimize storage, so it can only load very small language models

Note that all probabilities in the grammar are stored in LogMath log base format. Language Probabilities in the language model file are stored in log 10 base.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String	fileName
protected int	lineNumber
protected java.io.BufferedReader	reader

Fields inherited from interface edu.cmu.sphinx.linguist.language.ngram.LanguageModel

PROP_DICTIONARY, PROP_LOCATION, PROP_MAX_DEPTH, PROP_UNIGRAM_WEIGHT

Constructor Summary

Constructors

Constructor and Description
SimpleNGramModel()
SimpleNGramModel(java.lang.String location, Dictionary dictionary, float unigramWeight, int desiredMaxDepth)
SimpleNGramModel(java.net.URL urlLocation, Dictionary dictionary, float unigramWeight, int desiredMaxDepth)

Method Summary

Modifier and Type	Method and Description
void	allocate() Create the language model
void	deallocate() Deallocate resources allocated to this language model
void	dump() Dumps the language model
float	getBackoff(WordSequence wordSequence) Returns the backoff probability for the give sequence of words
int	getMaxDepth() Returns the maximum depth of the language model
java.lang.String	getName()
java.util.LinkedList<WordSequence>	getNGrams() Returns a list of all the word sequences in the language model This method is used to create Finite State Transducers of the language model.
float	getProbability(WordSequence wordSequence) Gets the ngram probability of the word sequence represented by the word list
float	getSmear(WordSequence wordSequence) Gets the smear term for the given wordSequence
java.util.Set<java.lang.String>	getVocabulary() Returns the set of words in the language model.
void	newProperties(PropertySheet ps) This method is called when this configurable component needs to be reconfigured.
void	onUtteranceEnd() Called on utterance end to clear cache if needed

Methods inherited from class java.lang.Object

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

Field Detail

lineNumber

protected int lineNumber

reader

protected java.io.BufferedReader reader

fileName

protected java.lang.String fileName

Constructor Detail

SimpleNGramModel

public SimpleNGramModel(java.lang.String location,
                        Dictionary dictionary,
                        float unigramWeight,
                        int desiredMaxDepth)
                 throws java.net.MalformedURLException,
                        java.lang.ClassNotFoundException

Throws:

java.net.MalformedURLException

java.lang.ClassNotFoundException

SimpleNGramModel

public SimpleNGramModel(java.net.URL urlLocation,
                        Dictionary dictionary,
                        float unigramWeight,
                        int desiredMaxDepth)

SimpleNGramModel

public SimpleNGramModel()

Method Detail

newProperties

public void newProperties(PropertySheet ps)
                   throws PropertyException

Description copied from interface: Configurable

This method is called when this configurable component needs to be reconfigured.

Specified by:

newProperties in interface Configurable

Parameters:

ps - a property sheet holding the new data

Throws:

PropertyException - if there is a problem with the properties.

allocate

public void allocate()
              throws java.io.IOException

Description copied from interface: LanguageModel

Create the language model

Specified by:

allocate in interface LanguageModel

Throws:

java.io.IOException - if error occurrs

deallocate

public void deallocate()

Description copied from interface: LanguageModel

Deallocate resources allocated to this language model

Specified by:

deallocate in interface LanguageModel

getName

public java.lang.String getName()

getProbability

public float getProbability(WordSequence wordSequence)

Gets the ngram probability of the word sequence represented by the word list

Specified by:

getProbability in interface LanguageModel

Parameters:

wordSequence - the word sequence

Returns:

the probability of the word sequence. Probability is in logMath log base

getSmear

public float getSmear(WordSequence wordSequence)

Gets the smear term for the given wordSequence

Specified by:

getSmear in interface LanguageModel

Parameters:

wordSequence - the word sequence

Returns:

the smear term associated with this word sequence

getBackoff

public float getBackoff(WordSequence wordSequence)

Returns the backoff probability for the give sequence of words

Parameters:

wordSequence - the sequence of words

Returns:

the backoff probability in LogMath log base

getMaxDepth

public int getMaxDepth()

Returns the maximum depth of the language model

Specified by:

getMaxDepth in interface LanguageModel

Returns:

the maximum depth of the language model

getVocabulary

public java.util.Set<java.lang.String> getVocabulary()

Returns the set of words in the language model. The set is unmodifiable.

Specified by:

getVocabulary in interface LanguageModel

Returns:

the unmodifiable set of words

onUtteranceEnd

public void onUtteranceEnd()

Description copied from interface: LanguageModel

Called on utterance end to clear cache if needed

Specified by:

onUtteranceEnd in interface LanguageModel

dump

public void dump()

Dumps the language model

getNGrams

public java.util.LinkedList<WordSequence> getNGrams()

Returns a list of all the word sequences in the language model This method is used to create Finite State Transducers of the language model.

Returns:

List containing all the word sequences