Package edu.cmu.tetrad.sem

Class SemOptimizerEm

java.lang.Object

edu.cmu.tetrad.sem.SemOptimizerEm

All Implemented Interfaces:

SemOptimizer, TetradSerializable, Serializable

public class SemOptimizerEm
extends Object
implements SemOptimizer

Optimizes a DAG SEM with hidden variables using expectation-maximization. IT SHOULD NOT BE USED WITH SEMs THAT ARE NOT DAGS. For DAGs without hidden variables, SemOptimizerRegression should be more efficient.

Version:

$Id: $Id

Author:

Ricardo Silva, josephramsey Cleanup, modernization.

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
SemOptimizerEm()	Constructor for SemOptimizerEm.

Method Summary

Modifier and Type	Method	Description
int	getNumRestarts()	Returns the number of restarts for the optimization process.
void	optimize(SemIm semIm)	Optimizes an unoptimized Sem object by minimizing the chi-square statistic.
static SemOptimizerEm	serializableInstance()	Generates a simple exemplar of this class to test serialization.
void	setNumRestarts(int numRestarts)	setNumRestarts.
String	toString()	toString.

Methods inherited from class java.lang.Object

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

Constructor Details

SemOptimizerEm

public SemOptimizerEm()

Constructor for SemOptimizerEm.

Method Details

serializableInstance

public static SemOptimizerEm serializableInstance()

Generates a simple exemplar of this class to test serialization.

Returns:

a SemOptimizerEm object

optimize

public void optimize(SemIm semIm)

Optimizes an unoptimized Sem object by minimizing the chi-square statistic.

Specified by:

optimize in interface SemOptimizer

Parameters:

semIm - The unoptimized Sem object to be optimized.

Throws:

NullPointerException - If the sample covariance matrix has not been set.

IllegalArgumentException - If the sample covariance matrix contains missing values.

RuntimeException - If an error occurs during optimization.

getNumRestarts

public int getNumRestarts()

Returns the number of restarts for the optimization process.

Specified by:

getNumRestarts in interface SemOptimizer

Returns:

The number of restarts for the optimization process.

setNumRestarts

public void setNumRestarts(int numRestarts)

setNumRestarts.

Specified by:

setNumRestarts in interface SemOptimizer

Parameters:

numRestarts - a int

toString

public String toString()

toString.

Overrides:

toString in class Object

Returns:

a String object