be.ac.ulg.montefiore.run.jahmm.learn
Class BaumWelchScaledLearner

java.lang.Object
  extended by be.ac.ulg.montefiore.run.jahmm.learn.BaumWelchLearner
      extended by be.ac.ulg.montefiore.run.jahmm.learn.BaumWelchScaledLearner

public class BaumWelchScaledLearner
extends BaumWelchLearner

An implementation of the Baum-Welch learning algorithm. It uses a scaling mechanism so as to avoid underflows.

For more information on the scaling procedure, read Rabiner and Juang's Fundamentals of speech recognition (Prentice Hall, 1993).


Constructor Summary
BaumWelchScaledLearner()
          Initializes a Baum-Welch algorithm implementation.
 
Method Summary
protected
<O extends Observation>
double[][][]
estimateXi(java.util.List<? extends O> sequence, ForwardBackwardCalculator fbc, Hmm<O> hmm)
           
protected
<O extends Observation>
ForwardBackwardCalculator
generateForwardBackwardCalculator(java.util.List<? extends O> sequence, Hmm<O> hmm)
           
 
Methods inherited from class be.ac.ulg.montefiore.run.jahmm.learn.BaumWelchLearner
estimateGamma, getNbIterations, iterate, learn, setNbIterations
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BaumWelchScaledLearner

public BaumWelchScaledLearner()
Initializes a Baum-Welch algorithm implementation.

Method Detail

generateForwardBackwardCalculator

protected <O extends Observation> ForwardBackwardCalculator generateForwardBackwardCalculator(java.util.List<? extends O> sequence,
                                                                                              Hmm<O> hmm)
Overrides:
generateForwardBackwardCalculator in class BaumWelchLearner

estimateXi

protected <O extends Observation> double[][][] estimateXi(java.util.List<? extends O> sequence,
                                                          ForwardBackwardCalculator fbc,
                                                          Hmm<O> hmm)
Overrides:
estimateXi in class BaumWelchLearner


Copyright © 2004,2005 Jean-Marc François.