cc.mallet.grmm.inference
Class VariableElimination

java.lang.Object
  cc.mallet.grmm.inference.AbstractInferencer
      cc.mallet.grmm.inference.VariableElimination

All Implemented Interfaces:

Inferencer, java.io.Serializable, java.lang.Cloneable

public class VariableElimination
extends AbstractInferencer

The variable elimination algorithm for inference in graphical models. Created: Mon Sep 22 17:34:00 2003

Version:

$Id: VariableElimination.java,v 1.1 2007/10/22 21:37:49 mccallum Exp $

Author:

Charles Sutton

See Also:

Serialized Form

Constructor Summary

VariableElimination()

Method Summary

void	computeMarginals(FactorGraph m) Computes marginal distributions for a factor graph.
double	computeNormalizationFactor(FactorGraph m) Computes the normalization constant for a model.
Factor	lookupMarginal(Variable var) Returns the computed marginal of a given variable.
Factor	unnormalizedMarginal(FactorGraph model, Variable query) The bulk of the variable-elimination algorithm.

Methods inherited from class cc.mallet.grmm.inference.AbstractInferencer

dump, duplicate, lookupJoint, lookupLogJoint, lookupMarginal, query, reportTime

Methods inherited from class java.lang.Object

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

Constructor Detail

VariableElimination

public VariableElimination()

Method Detail

unnormalizedMarginal

public Factor unnormalizedMarginal(FactorGraph model,
                                   Variable query)

The bulk of the variable-elimination algorithm. Returns the marginal density of the variable QUERY in the undirected model MODEL, except that the density is un-normalized. The normalization is done in a separate function to make computeNormalizationFactor easier.

computeNormalizationFactor

public double computeNormalizationFactor(FactorGraph m)

Computes the normalization constant for a model.

computeMarginals

public void computeMarginals(FactorGraph m)

Description copied from interface: Inferencer

Computes marginal distributions for a factor graph.

Specified by:

computeMarginals in interface Inferencer

Specified by:

computeMarginals in class AbstractInferencer

lookupMarginal

public Factor lookupMarginal(Variable var)

Description copied from interface: Inferencer

Returns the computed marginal of a given variable. Before using this method, computeMarginals must have been previously called on the graphical model that contains v.

Specified by:

lookupMarginal in interface Inferencer

Specified by:

lookupMarginal in class AbstractInferencer

See Also:

Inferencer.computeMarginals(FactorGraph)