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.

Version:

$Id: $Id

Author:

josephramsey

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
CptInvariantUpdater(BayesIm bayesIm)	Constructor for CptInvariantUpdater.
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)	Calculates the prior marginal probabilities of the given node.
double[]	calculateUpdatedMarginals(int nodeIndex)	Calculates the updated marginal probabilities of the given node, given the evidence.
BayesIm	getBayesIm()	Getter for the field bayesIm.
Evidence	getEvidence()	Getter for the field evidence.
double	getJointMarginal(int[] variables, int[] values)	getJointMarginal.
BayesIm	getManipulatedBayesIm()	Getter for the field manipulatedBayesIm.
Graph	getManipulatedGraph()	getManipulatedGraph.
double	getMarginal(int variable, int value)	Returns the marginal probability of the given variable taking the given value, given the evidence.
BayesIm	getUpdatedBayesIm()	Getter for the field updatedBayesIm.
boolean	isJointMarginalSupported()	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

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

CptInvariantUpdater

public CptInvariantUpdater(BayesIm bayesIm)

Constructor for CptInvariantUpdater.

Parameters:

bayesIm - a BayesIm object

CptInvariantUpdater

public CptInvariantUpdater(BayesIm bayesIm,
 Evidence evidence)

Constructs a new updater for the given Bayes net.

Parameters:

bayesIm - a BayesIm object

evidence - a Evidence object

Method Details

serializableInstance

public static CptInvariantUpdater serializableInstance()

Generates a simple exemplar of this class to test serialization.

Returns:

a CptInvariantUpdater object

getBayesIm

public BayesIm getBayesIm()

Getter for the field bayesIm.

Specified by:

getBayesIm in interface BayesUpdater

Returns:

a BayesIm object

getManipulatedBayesIm

public BayesIm getManipulatedBayesIm()

Getter for the field manipulatedBayesIm.

Specified by:

getManipulatedBayesIm in interface ManipulatingBayesUpdater

Returns:

a BayesIm object

getManipulatedGraph

public Graph getManipulatedGraph()

getManipulatedGraph.

Specified by:

getManipulatedGraph in interface ManipulatingBayesUpdater

Returns:

a Graph object

getUpdatedBayesIm

public BayesIm getUpdatedBayesIm()

Getter for the field updatedBayesIm.

Specified by:

getUpdatedBayesIm in interface ManipulatingBayesUpdater

Returns:

a BayesIm object

getEvidence

public Evidence getEvidence()

Getter for the field evidence.

Specified by:

getEvidence in interface ManipulatingBayesUpdater

Returns:

a Evidence object

setEvidence

public void setEvidence(Evidence evidence)

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

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

Parameters:

evidence - evidence

getMarginal

public double getMarginal(int variable,
 int value)

Returns the marginal probability of the given variable taking the given value, given the evidence.

Returns the updated graph. This is the graph in which all probabilities of variables conditional on their parents have been updated.

Specified by:

getMarginal in interface BayesUpdater

Specified by:

getMarginal in interface ManipulatingBayesUpdater

Parameters:

variable - variable index

value - category index

Returns:

P(variable = value | evidence), where evidence is getEvidence().

isJointMarginalSupported

public boolean isJointMarginalSupported()

isJointMarginalSupported.

Specified by:

isJointMarginalSupported in interface BayesUpdater

Returns:

a boolean

getJointMarginal

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

getJointMarginal.

Specified by:

getJointMarginal in interface BayesUpdater

Parameters:

variables - an array of objects

values - an array of objects

Returns:

a double

calculatePriorMarginals

public double[] calculatePriorMarginals(int nodeIndex)

Calculates the prior marginal probabilities of the given node.

Specified by:

calculatePriorMarginals in interface BayesUpdater

Parameters:

nodeIndex - node index

Returns:

P(node = value), where value is the value of the node in the Bayes net.

calculateUpdatedMarginals

public double[] calculateUpdatedMarginals(int nodeIndex)

Calculates the updated marginal probabilities of the given node, given the evidence.

Specified by:

calculateUpdatedMarginals in interface BayesUpdater

Parameters:

nodeIndex - node index

Returns:

P(node = value | evidence), where value is the value of the node in the Bayes net.

toString

public String toString()

Prints out the most recent marginal.

Overrides:

toString in class Object

Returns:

a String object