org.apache.openejb.math.stat.descriptive

Class AbstractStorelessUnivariateStatistic

java.lang.Object

org.apache.openejb.math.stat.descriptive.AbstractUnivariateStatistic

org.apache.openejb.math.stat.descriptive.AbstractStorelessUnivariateStatistic

All Implemented Interfaces:

StorelessUnivariateStatistic, UnivariateStatistic

Direct Known Subclasses:

FirstMoment, GeometricMean, Kurtosis, Max, Mean, Min, Skewness, Sum, SumOfLogs, SumOfSquares, Variance

public abstract class AbstractStorelessUnivariateStatistic
extends AbstractUnivariateStatistic
implements StorelessUnivariateStatistic

Abstract implementation of the StorelessUnivariateStatistic interface.

Provides default evaluate() and incrementAll(double[]) implementations.

Note that these implementations are not synchronized.

Version:

$Revision: 811833 $ $Date: 2009-09-06 09:27:50 -0700 (Sun, 06 Sep 2009) $

Constructor Summary

Constructors

Constructor and Description
AbstractStorelessUnivariateStatistic()

Method Summary

Methods

Modifier and Type	Method and Description
abstract void	clear() Clears the internal state of the Statistic
abstract StorelessUnivariateStatistic	copy() Returns a copy of the statistic with the same internal state.
boolean	equals(Object object) Returns true iff object is an AbstractStorelessUnivariateStatistic returning the same values as this for getResult() and getN()
double	evaluate(double[] values) This default implementation calls clear(), then invokes increment(double) in a loop over the the input array, and then uses getResult() to compute the return value.
double	evaluate(double[] values, int begin, int length) This default implementation calls clear(), then invokes increment(double) in a loop over the specified portion of the input array, and then uses getResult() to compute the return value.
abstract double	getResult() Returns the current value of the Statistic.
int	hashCode() Returns hash code based on getResult() and getN()
abstract void	increment(double d) Updates the internal state of the statistic to reflect the addition of the new value.
void	incrementAll(double[] values) This default implementation just calls increment(double) in a loop over the input array.
void	incrementAll(double[] values, int begin, int length) This default implementation just calls increment(double) in a loop over the specified portion of the input array.

Methods inherited from class org.apache.openejb.math.stat.descriptive.AbstractUnivariateStatistic

test, test

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.openejb.math.stat.descriptive.StorelessUnivariateStatistic

getN

Constructor Detail

AbstractStorelessUnivariateStatistic

public AbstractStorelessUnivariateStatistic()

Method Detail

evaluate

public double evaluate(double[] values)

This default implementation calls clear(), then invokes increment(double) in a loop over the the input array, and then uses getResult() to compute the return value.

Note that this implementation changes the internal state of the statistic. Its side effects are the same as invoking clear() and then incrementAll(double[]).

Implementations may override this method with a more efficient and possibly more accurate implementation that works directly with the input array.

If the array is null, an IllegalArgumentException is thrown.

Specified by:

evaluate in interface UnivariateStatistic

Overrides:

evaluate in class AbstractUnivariateStatistic

Parameters:

values - input array

Returns:

the value of the statistic applied to the input array

See Also:

UnivariateStatistic.evaluate(double[])

evaluate

public double evaluate(double[] values,
              int begin,
              int length)

This default implementation calls clear(), then invokes increment(double) in a loop over the specified portion of the input array, and then uses getResult() to compute the return value.

Note that this implementation changes the internal state of the statistic. Its side effects are the same as invoking clear() and then incrementAll(double[], int, int).

Implementations may override this method with a more efficient and possibly more accurate implementation that works directly with the input array.

If the array is null or the index parameters are not valid, an IllegalArgumentException is thrown.

Specified by:

evaluate in interface UnivariateStatistic

Specified by:

evaluate in class AbstractUnivariateStatistic

Parameters:

values - the input array

begin - the index of the first element to include

length - the number of elements to include

Returns:

the value of the statistic applied to the included array entries

See Also:

UnivariateStatistic.evaluate(double[], int, int)

copy

public abstract StorelessUnivariateStatistic copy()

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

Specified by:

copy in interface StorelessUnivariateStatistic

Specified by:

copy in interface UnivariateStatistic

Specified by:

copy in class AbstractUnivariateStatistic

Returns:

a copy of the statistic

clear

public abstract void clear()

Clears the internal state of the Statistic

Specified by:

clear in interface StorelessUnivariateStatistic

getResult

public abstract double getResult()

Returns the current value of the Statistic.

Specified by:

getResult in interface StorelessUnivariateStatistic

Returns:

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

increment

public abstract void increment(double d)

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

Specified by:

increment in interface StorelessUnivariateStatistic

Parameters:

d - the new value.

incrementAll

public void incrementAll(double[] values)

This default implementation just calls increment(double) in a loop over the input array.

Throws IllegalArgumentException if the input values array is null.

Specified by:

incrementAll in interface StorelessUnivariateStatistic

Parameters:

values - values to add

Throws:

IllegalArgumentException - if values is null

See Also:

StorelessUnivariateStatistic.incrementAll(double[])

incrementAll

public void incrementAll(double[] values,
                int begin,
                int length)

This default implementation just calls increment(double) in a loop over the specified portion of the input array.

Throws IllegalArgumentException if the input values array is null.

Specified by:

incrementAll in interface StorelessUnivariateStatistic

Parameters:

values - array holding values to add

begin - index of the first array element to add

length - number of array elements to add

Throws:

IllegalArgumentException - if values is null

See Also:

StorelessUnivariateStatistic.incrementAll(double[], int, int)

equals

public boolean equals(Object object)

Returns true iff object is an AbstractStorelessUnivariateStatistic returning the same values as this for getResult() and getN()

Overrides:

equals in class Object

Parameters:

object - object to test equality against.

Returns:

true if object returns the same value as this

hashCode

public int hashCode()

Returns hash code based on getResult() and getN()

Overrides:

hashCode in class Object

Returns:

hash code