Package edu.cmu.tetrad.bayes

Class CptInvariantUpdater

java.lang.Object

edu.cmu.tetrad.bayes.CptInvariantUpdater

All Implemented Interfaces:

BayesUpdater, ManipulatingBayesUpdater, TetradSerializable, Serializable

public final class CptInvariantUpdater
extends Object
implements ManipulatingBayesUpdater

Calculates updated probabilities for variables conditional on their parents as well as single-variable updated marginals for a Bayes IM using an algorithm that restricts expensive updating summations only to conditional probabilities of variables with respect to their parents that change from non-updated to updated values.

Author:

Joseph Ramsey

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
CptInvariantUpdater(BayesIm bayesIm)
CptInvariantUpdater(BayesIm bayesIm, Evidence evidence)	Constructs a new updater for the given Bayes net.

Method Summary

Modifier and Type	Method	Description
double[]	calculatePriorMarginals(int nodeIndex)
double[]	calculateUpdatedMarginals(int nodeIndex)
BayesIm	getBayesIm()
Evidence	getEvidence()
double	getJointMarginal(int[] variables, int[] values)
BayesIm	getManipulatedBayesIm()
Graph	getManipulatedGraph()
double	getMarginal(int variable, int value)
BayesIm	getUpdatedBayesIm()
boolean	isJointMarginalSupported()
static CptInvariantUpdater	serializableInstance()	Generates a simple exemplar of this class to test serialization.
void	setEvidence(Evidence evidence)	Sets new evidence for the updater.
String	toString()	Prints out the most recent marginal.

Methods inherited from class java.lang.Object

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

Constructor Details

CptInvariantUpdater

public CptInvariantUpdater(BayesIm bayesIm)

CptInvariantUpdater

public CptInvariantUpdater(BayesIm bayesIm,
 Evidence evidence)

Constructs a new updater for the given Bayes net.

Method Details

serializableInstance

public static CptInvariantUpdater serializableInstance()

Generates a simple exemplar of this class to test serialization.

getBayesIm

public BayesIm getBayesIm()

Specified by:

getBayesIm in interface BayesUpdater

Returns:

the Bayes instantiated model that is being updated.

getManipulatedBayesIm

public BayesIm getManipulatedBayesIm()

Specified by:

getManipulatedBayesIm in interface ManipulatingBayesUpdater

Returns:

the Bayes instantiated model after manipulations have been applied.

getManipulatedGraph

public Graph getManipulatedGraph()

Specified by:

getManipulatedGraph in interface ManipulatingBayesUpdater

Returns:

the graph for the manipulated BayesIm.

getUpdatedBayesIm

public BayesIm getUpdatedBayesIm()

Specified by:

getUpdatedBayesIm in interface ManipulatingBayesUpdater

Returns:

the updated Bayes IM--that is, the Bayes IM in which all probabilities of variables conditional on their parents have been updated.

getEvidence

public Evidence getEvidence()

Specified by:

getEvidence in interface ManipulatingBayesUpdater

Returns:

a defensive copy of the evidence.

setEvidence

public void setEvidence(Evidence evidence)

Description copied from interface: ManipulatingBayesUpdater

Sets new evidence for the updater. Once this is called, old updating results should not longer be available.

Specified by:

setEvidence in interface BayesUpdater

Specified by:

setEvidence in interface ManipulatingBayesUpdater

getMarginal

public double getMarginal(int variable,
 int value)

Specified by:

getMarginal in interface BayesUpdater

Specified by:

getMarginal in interface ManipulatingBayesUpdater

Returns:

P(variable = category | evidence) where evidence is getEvidence().

isJointMarginalSupported

public boolean isJointMarginalSupported()

Specified by:

isJointMarginalSupported in interface BayesUpdater

Returns:

true if the getJointMarginal() method is supported.

getJointMarginal

public double getJointMarginal(int[] variables,
 int[] values)

Specified by:

getJointMarginal in interface BayesUpdater

Returns:

P(variables[i] = values[i] | evidence), where evidence is getEvidence().

calculatePriorMarginals

public double[] calculatePriorMarginals(int nodeIndex)

Specified by:

calculatePriorMarginals in interface BayesUpdater

calculateUpdatedMarginals

public double[] calculateUpdatedMarginals(int nodeIndex)

Specified by:

calculateUpdatedMarginals in interface BayesUpdater

toString

public String toString()

Prints out the most recent marginal.

Overrides:

toString in class Object