Package edu.cmu.tetrad.bayes

Class RowSummingExactUpdater

java.lang.Object

edu.cmu.tetrad.bayes.RowSummingExactUpdater

All Implemented Interfaces:

BayesUpdater, ManipulatingBayesUpdater, TetradSerializable, Serializable

public final class RowSummingExactUpdater
extends Object
implements ManipulatingBayesUpdater

Performs updating operations on a BayesIm by summing over cells in the joint probability table for the BayesIm. Quite flexible and fast if almost all of the variables in the Bayes net are in evidence. Can be excruciatingly slow if numVars - numVarsInEvidence is more than 15.

Author:

Joseph Ramsey

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
RowSummingExactUpdater(BayesIm bayesIm)	Constructs a new updater for the given Bayes net.
RowSummingExactUpdater(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()	The BayesIm that this updater bases its update on.
Evidence	getEvidence()
double	getJointMarginal(int[] variables, int[] values)
BayesIm	getManipulatedBayesIm()
Graph	getManipulatedGraph()
double	getMarginal(int variable, int value)
BayesIm	getUpdatedBayesIm()	The updated BayesIm.
boolean	isJointMarginalSupported()
static RowSummingExactUpdater	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

RowSummingExactUpdater

public RowSummingExactUpdater(BayesIm bayesIm)

Constructs a new updater for the given Bayes net.

RowSummingExactUpdater

public RowSummingExactUpdater(BayesIm bayesIm,
 Evidence evidence)

Constructs a new updater for the given Bayes net.

Method Details

serializableInstance

public static RowSummingExactUpdater serializableInstance()

Generates a simple exemplar of this class to test serialization.

getBayesIm

public BayesIm getBayesIm()

The BayesIm that this updater bases its update on. This BayesIm is not modified; rather, a new BayesIm is created and updated.

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 updated BayesIm.

getManipulatedGraph

public Graph getManipulatedGraph()

Specified by:

getManipulatedGraph in interface ManipulatingBayesUpdater

Returns:

the graph for the manipulated BayesIm.

getUpdatedBayesIm

public BayesIm getUpdatedBayesIm()

The updated BayesIm. This is a different object from the source BayesIm.

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.

See Also:

• getBayesIm()

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

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().

getMarginal

public double getMarginal(int variable,
 int value)

Specified by:

getMarginal in interface BayesUpdater

Specified by:

getMarginal in interface ManipulatingBayesUpdater

Returns:

P(variable=value | 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