org.apache.mahout.vectorizer.encoders

Class WordValueEncoder

java.lang.Object

org.apache.mahout.vectorizer.encoders.FeatureVectorEncoder

org.apache.mahout.vectorizer.encoders.WordValueEncoder

Direct Known Subclasses:

AdaptiveWordValueEncoder, StaticWordValueEncoder

public abstract class WordValueEncoder
extends FeatureVectorEncoder

Encodes words as sparse vector updates to a Vector. Weighting is defined by a sub-class.

Field Summary

Fields inherited from class org.apache.mahout.vectorizer.encoders.FeatureVectorEncoder

CONTINUOUS_VALUE_HASH_SEED, WORD_LIKE_VALUE_HASH_SEED

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	WordValueEncoder(String name)

Method Summary

Modifier and Type	Method and Description
void	addToVector(byte[] originalForm, double w, Vector data) Adds a value to a vector.
String	asString(String originalForm) Converts a value into a form that would help a human understand the internals of how the value is being interpreted.
protected double	getWeight(byte[] originalForm, double w)
protected int	hashForProbe(byte[] originalForm, int dataSize, String name, int probe) Provides the unique hash for a particular probe.
protected abstract double	weight(byte[] originalForm)

Methods inherited from class org.apache.mahout.vectorizer.encoders.FeatureVectorEncoder

addToVector, addToVector, addToVector, bytesForString, getName, getProbes, hash, hash, hash, hash, hash, hashesForProbe, isTraceEnabled, setProbes, setTraceDictionary, trace, trace

Methods inherited from class java.lang.Object

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

Constructor Detail

WordValueEncoder

protected WordValueEncoder(String name)

Method Detail

addToVector

public void addToVector(byte[] originalForm,
                        double w,
                        Vector data)

Adds a value to a vector.

Specified by:

addToVector in class FeatureVectorEncoder

Parameters:

originalForm - The original form of the value as a string.

data - The vector to which the value should be added.

getWeight

protected double getWeight(byte[] originalForm,
                           double w)

Overrides:

getWeight in class FeatureVectorEncoder

hashForProbe

protected int hashForProbe(byte[] originalForm,
                           int dataSize,
                           String name,
                           int probe)

Description copied from class: FeatureVectorEncoder

Provides the unique hash for a particular probe. For all encoders except text, this is all that is needed and the default implementation of hashesForProbe will do the right thing. For text and similar values, hashesForProbe should be over-ridden and this method should not be used.

Specified by:

hashForProbe in class FeatureVectorEncoder

Parameters:

originalForm - The original byte array value

dataSize - The length of the vector being encoded

name - The name of the variable being encoded

probe - The probe number

Returns:

The hash of the current probe

asString

public String asString(String originalForm)

Converts a value into a form that would help a human understand the internals of how the value is being interpreted. For text-like things, this is likely to be a list of the terms found with associated weights (if any).

Specified by:

asString in class FeatureVectorEncoder

Parameters:

originalForm - The original form of the value as a string.

Returns:

A string that a human can read.

weight

protected abstract double weight(byte[] originalForm)