weka.estimators
Class NormalEstimator

java.lang.Object
  weka.estimators.NormalEstimator

All Implemented Interfaces:

Estimator, java.io.Serializable

public class NormalEstimator

extends java.lang.Object

implements Estimator

Simple probability estimator that places a single normal distribution over the observed values.

Version:

$Revision: 1.5 $

Author:

Len Trigg (trigg@cs.waikato.ac.nz)

See Also:

Serialized Form

Field Summary

private double	m_Mean The current mean
private double	m_Precision The precision of numeric values ( = minimum std dev permitted)
private double	m_StandardDev The current standard deviation
private double	m_SumOfValues The sum of the values seen
private double	m_SumOfValuesSq The sum of the values squared
private double	m_SumOfWeights The sum of the weights

Constructor Summary

NormalEstimator(double precision)
Constructor that takes a precision argument.

Method Summary

void	addValue(double data, double weight) Add a new data value to the current estimator.
double	getProbability(double data) Get a probability estimate for a value
static void	main(java.lang.String[] argv) Main method for testing this class.
private double	round(double data) Round a data value using the defined precision for this estimator
java.lang.String	toString() Display a representation of this estimator

Methods inherited from class java.lang.Object

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

Field Detail

m_SumOfWeights

private double m_SumOfWeights

The sum of the weights

m_SumOfValues

private double m_SumOfValues

The sum of the values seen

m_SumOfValuesSq

private double m_SumOfValuesSq

The sum of the values squared

m_Mean

private double m_Mean

The current mean

m_StandardDev

private double m_StandardDev

The current standard deviation

m_Precision

private double m_Precision

The precision of numeric values ( = minimum std dev permitted)

Constructor Detail

NormalEstimator

public NormalEstimator(double precision)

Constructor that takes a precision argument.

Parameters:

precision - the precision to which numeric values are given. For example, if the precision is stated to be 0.1, the values in the interval (0.25,0.35] are all treated as 0.3.

Method Detail

round

private double round(double data)

Round a data value using the defined precision for this estimator

Parameters:

data - the value to round

Returns:

the rounded data value

addValue

public void addValue(double data,
                     double weight)

Add a new data value to the current estimator.

Specified by:

addValue in interface Estimator

Parameters:

data - the new data value

weight - the weight assigned to the data value

getProbability

public double getProbability(double data)

Get a probability estimate for a value

Specified by:

getProbability in interface Estimator

Parameters:

data - the value to estimate the probability of

Returns:

the estimated probability of the supplied value

toString

public java.lang.String toString()

Display a representation of this estimator

main

public static void main(java.lang.String[] argv)

Main method for testing this class.

Parameters:

argv - should contain a sequence of numeric values