peersim.util
Class IncrementalStats

java.lang.Object
  peersim.util.IncrementalStats

Direct Known Subclasses:

MedianStats, MomentStats

public class IncrementalStats
extends java.lang.Object

A class that can keep track of some statistics like variance, average, min, max incrementally. That is, when adding a new data item, it updates the statistics.

Constructor Summary

IncrementalStats()
Calls reset().

Method Summary

void	add(double item) Updates the statistics according to this element.
void	add(double item, int k) Updates the statistics assuming element item is added k times.
double	getAverage() The average of the data items
double	getMax() The maximum of the data items
int	getMaxCount() Returns the number of data items whose value equals the maximum.
double	getMin() The minimum of the data items
int	getMinCount() Returns the number of data items whose value equals the minimum.
int	getN() The number of data items processed so far
double	getSqrSum() The sum of the squares of the data items
double	getStD() the empirical standard deviation of the data items
double	getSum() The sum of the data items
double	getVar() The empirical variance of the data items.
void	reset() Resets the statistics to reflect the zero elements set.
java.lang.String	toString() Prints the following quantities separated by spaces in a single line in this order.

Methods inherited from class java.lang.Object

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

Constructor Detail

IncrementalStats

public IncrementalStats()

Calls reset().

Method Detail

reset

public void reset()

Resets the statistics to reflect the zero elements set. Min and max are set to positive and negative infinity, respectively.

add

public final void add(double item)

Updates the statistics according to this element. It calls add(item,1).

See Also:

add(double,int)

add

public void add(double item,
                int k)

Updates the statistics assuming element item is added k times.

getN

public int getN()

The number of data items processed so far

getMax

public double getMax()

The maximum of the data items

getMin

public double getMin()

The minimum of the data items

getMaxCount

public int getMaxCount()

Returns the number of data items whose value equals the maximum.

getMinCount

public int getMinCount()

Returns the number of data items whose value equals the minimum.

getSum

public double getSum()

The sum of the data items

getSqrSum

public double getSqrSum()

The sum of the squares of the data items

getAverage

public double getAverage()

The average of the data items

getVar

public double getVar()

The empirical variance of the data items. Guaranteed to be larger or equal to 0.0. If due to rounding errors the value becomes negative, it returns 0.0.

getStD

public double getStD()

the empirical standard deviation of the data items

toString

public java.lang.String toString()

Prints the following quantities separated by spaces in a single line in this order. Minimum, maximum, number of items, average, variance, number of minimal items, number of maximal items.

Overrides:

toString in class java.lang.Object