Package org.apache.commons.math.stat.descriptive

Interface StorelessUnivariateStatistic

All Superinterfaces:

UnivariateStatistic

All Known Implementing Classes:

AbstractStorelessUnivariateStatistic, FirstMoment, FourthMoment, GeometricMean, Kurtosis, Max, Mean, Min, Product, SecondMoment, Skewness, StandardDeviation, Sum, SumOfLogs, SumOfSquares, ThirdMoment, Variance

public interface StorelessUnivariateStatistic
extends UnivariateStatistic

Extends the definition of UnivariateStatistic with increment(double) and incrementAll(double[]) methods for adding values and updating internal state.

This interface is designed to be used for calculating statistics that can be computed in one pass through the data without storing the full array of sample values.

Version:

$Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $

Method Summary

Modifier and Type	Method	Description
void	clear()	Clears the internal state of the Statistic
StorelessUnivariateStatistic	copy()	Returns a copy of the statistic with the same internal state.
long	getN()	Returns the number of values that have been added.
double	getResult()	Returns the current value of the Statistic.
void	increment(double d)	Updates the internal state of the statistic to reflect the addition of the new value.
void	incrementAll(double[] values)	Updates the internal state of the statistic to reflect addition of all values in the values array.
void	incrementAll(double[] values, int start, int length)	Updates the internal state of the statistic to reflect addition of the values in the designated portion of the values array.

Methods inherited from interface org.apache.commons.math.stat.descriptive.UnivariateStatistic

evaluate, evaluate

Method Detail

increment

void increment(double d)

Updates the internal state of the statistic to reflect the addition of the new value.

Parameters:

d - the new value.

incrementAll

void incrementAll(double[] values)

Updates the internal state of the statistic to reflect addition of all values in the values array. Does not clear the statistic first -- i.e., the values are added incrementally to the dataset.

Parameters:

values - array holding the new values to add

Throws:

java.lang.IllegalArgumentException - if the array is null

incrementAll

void incrementAll(double[] values,
                  int start,
                  int length)

Updates the internal state of the statistic to reflect addition of the values in the designated portion of the values array. Does not clear the statistic first -- i.e., the values are added incrementally to the dataset.

Parameters:

values - array holding the new values to add

start - the array index of the first value to add

length - the number of elements to add

Throws:

java.lang.IllegalArgumentException - if the array is null or the index

getResult

double getResult()

Returns the current value of the Statistic.

Returns:

value of the statistic, Double.NaN if it has been cleared or just instantiated.

getN

long getN()

Returns the number of values that have been added.

Returns:

the number of values.

clear

void clear()

Clears the internal state of the Statistic

copy

StorelessUnivariateStatistic copy()

Returns a copy of the statistic with the same internal state.

Specified by:

copy in interface UnivariateStatistic

Returns:

a copy of the statistic