org.apache.mahout.vectorizer.encoders
Class ConstantValueEncoder

java.lang.Object
  extended by org.apache.mahout.vectorizer.encoders.FeatureVectorEncoder
      extended by org.apache.mahout.vectorizer.encoders.ConstantValueEncoder

public class ConstantValueEncoder
extends FeatureVectorEncoder

An encoder that does the standard thing for a virtual bias term.


Field Summary
 
Fields inherited from class org.apache.mahout.vectorizer.encoders.FeatureVectorEncoder
CONTINUOUS_VALUE_HASH_SEED, WORD_LIKE_VALUE_HASH_SEED
 
Constructor Summary
ConstantValueEncoder(java.lang.String name)
           
 
Method Summary
 void addToVector(byte[] originalForm, double weight, Vector data)
           
 java.lang.String asString(java.lang.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, java.lang.String name, int probe)
          Provides the unique hash for a particular probe.
 
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

ConstantValueEncoder

public ConstantValueEncoder(java.lang.String name)
Method Detail

addToVector

public void addToVector(byte[] originalForm,
                        double weight,
                        Vector data)
Specified by:
addToVector in class FeatureVectorEncoder

getWeight

protected double getWeight(byte[] originalForm,
                           double w)
Overrides:
getWeight in class FeatureVectorEncoder

asString

public java.lang.String asString(java.lang.String originalForm)
Description copied from class: FeatureVectorEncoder
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.

hashForProbe

protected int hashForProbe(byte[] originalForm,
                           int dataSize,
                           java.lang.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 hte vector being encoded
name - The name of the variable being encoded
probe - The probe number
Returns:
The hash of the current probe


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