edu.northwestern.at.utils.math.statistics

Class Accumulator

java.lang.Object

edu.northwestern.at.utils.math.statistics.Accumulator

public class Accumulator
extends java.lang.Object

Accumulate basic statistical information for a set of doubles.

Accumulates the following quantities.

• Count
• Maximum
• Minimum
• Mean
• Sum of squares

Returns these values as well as the variance and standard deviation.

Field Summary

Fields

Modifier and Type	Field and Description
protected long	count Count of elements.
protected double	maximum Maximum of elements.
protected double	mean Mean of elements.
protected double	minimum Minimum of elements.
protected double	sumOfSquares Sum of squares of elements.

Constructor Summary

Constructors

Constructor and Description
Accumulator() Create an empty accumulator.

Method Summary

Methods

Modifier and Type	Method and Description
void	addValue(double value) Add a value to the accumulation.
void	addValues(java.util.Collection<java.lang.Double> values) Add collection of values to the accumulation.
void	addValues(double[] values) Add array of values to the accumulation.
long	getCount() Return count.
double	getMaximum() Return maximum.
double	getMean() Return mean.
double	getMinimum() Return minimum.
double	getStandardDeviation() Return standard deviation.
double	getSumOfSquares() Return sum of squares.
double	getVariance() Return variance.

Methods inherited from class java.lang.Object

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

Field Detail

count

protected long count

Count of elements.

mean

protected double mean

Mean of elements.

sumOfSquares

protected double sumOfSquares

Sum of squares of elements.

minimum

protected double minimum

Minimum of elements.

maximum

protected double maximum

Maximum of elements.

Constructor Detail

Accumulator

public Accumulator()

Create an empty accumulator.

Method Detail

addValue

public void addValue(double value)

Add a value to the accumulation.

Parameters:

value - The value to add.

addValues

public void addValues(java.util.Collection<java.lang.Double> values)

Add collection of values to the accumulation.

Parameters:

values - The collection of values to add.

addValues

public void addValues(double[] values)

Add array of values to the accumulation.

Parameters:

values - The collection of values to add.

getCount

public long getCount()

Return count.

Returns:

Count of elements as a long.

getMaximum

public double getMaximum()

Return maximum.

Returns:

Maximum of elements.

getMinimum

public double getMinimum()

Return minimum.

Returns:

Minimum of elements.

getMean

public double getMean()

Return mean.

Returns:

Mean of elements.

getVariance

public double getVariance()

Return variance.

Returns:

Variance of elements.

The variance is the sum of squares divided by the number of values.

getStandardDeviation

public double getStandardDeviation()

Return standard deviation.

Returns:

Standard deviation of elements.

The standard deviation is the square root of the variance.

getSumOfSquares

public double getSumOfSquares()

Return sum of squares.

Returns:

Sum of squares of elements.