net.sf.jagg
Class AbstractCovarianceAggregator

java.lang.Object
  net.sf.jagg.Aggregator
      net.sf.jagg.TwoPropAggregator
          net.sf.jagg.AbstractCovarianceAggregator

Direct Known Subclasses:

CovarianceAggregator, CovariancePopAggregator

public abstract class AbstractCovarianceAggregator
extends TwoPropAggregator

This abstract class represents covariance-like aggregator calculations over numeric values.

Since:

0.3.0

Author:

Randy Gettman

Field Summary

protected long	myCount A running count of items processed so far where BOTH properties yield non-null values.
protected DoubleDouble	mySum1 A running sum of items processed so far for the FIRST property.
protected DoubleDouble	mySum2 A running sum of items processed so far for the SECOND property.
protected DoubleDouble	myVarNumerator A running total of the variance, before it is divided by the denominator in the variance calculation.

Fields inherited from class net.sf.jagg.Aggregator

PROP_SELF

Constructor Summary

AbstractCovarianceAggregator(java.lang.String properties)
Constructs a CovarianceAggregator on the specified properties, in the format: property, property2.

AbstractCovarianceAggregator(java.lang.String property, java.lang.String property2)
Constructs a CovarianceAggregator that operates on the specified properties.

Method Summary

void	init() Initialize the sums, count, and variance numerator to zero.
void	iterate(java.lang.Object value) Count only if both properties are non-null.
void	merge(Aggregator agg) Merge the given Aggregator into this one.

Methods inherited from class net.sf.jagg.TwoPropAggregator

getProperty2, setProperty, toString

Methods inherited from class net.sf.jagg.Aggregator

equals, getAggregator, getAggregator, getProperty, getValueFromProperty, hashCode, isInUse, replicate, setInUse, terminate, terminateDoubleDouble

Methods inherited from class java.lang.Object

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

Field Detail

myCount

protected long myCount

A running count of items processed so far where BOTH properties yield non-null values.

mySum1

protected DoubleDouble mySum1

A running sum of items processed so far for the FIRST property.

mySum2

protected DoubleDouble mySum2

A running sum of items processed so far for the SECOND property.

myVarNumerator

protected DoubleDouble myVarNumerator

A running total of the variance, before it is divided by the denominator in the variance calculation.

Constructor Detail

AbstractCovarianceAggregator

public AbstractCovarianceAggregator(java.lang.String properties)

Constructs a CovarianceAggregator on the specified properties, in the format: property, property2.

Parameters:

properties - A specification string in the format: property, property2.

AbstractCovarianceAggregator

public AbstractCovarianceAggregator(java.lang.String property,
                                    java.lang.String property2)

Constructs a CovarianceAggregator that operates on the specified properties.

Parameters:

property - Determine the covariance of this property with the other.

property2 - Determine the covariance of this property with the other.

Method Detail

init

public void init()

Initialize the sums, count, and variance numerator to zero.

Specified by:

init in class Aggregator

iterate

public void iterate(java.lang.Object value)

Count only if both properties are non-null. Sum both properties. Update the variance numerator.

Specified by:

iterate in class Aggregator

Parameters:

value - The value to aggregate.

See Also:

Aggregator.getValueFromProperty(java.lang.Object, java.lang.String)

merge

public void merge(Aggregator agg)

Merge the given Aggregator into this one. Add the sums together. Add in the count. Update the variance numerator.

Specified by:

merge in class Aggregator

Parameters:

agg - The Aggregator to merge into this one.