/*
* File: WeightedRingAverager.java
* Authors: Kevin R. Dixon
* Company: Sandia National Laboratories
* Project: Cognitive Foundry
*
* Copyright Feb 4, 2010, Sandia Corporation.
* Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
* license for use of this work by or on behalf of the U.S. Government.
* Export of this program may require a license from the United States
* Government. See CopyrightHistory.txt for complete details.
*
*/
package gov.sandia.cognition.math;
import gov.sandia.cognition.util.AbstractCloneableSerializable;
import gov.sandia.cognition.util.Summarizer;
import gov.sandia.cognition.util.WeightedValue;
import java.util.Collection;
/**
* A type of Summarizer for Rings (Matrices, Vectors, ComplexNumbers). Returns
* the arithmetic weighted mean of a Collection of Rings.
* @param <RingType> Type of Ring to average.
* @author Kevin R. Dixon
* @since 3.0
*/
public class WeightedRingAverager<RingType extends Ring<RingType>>
extends AbstractCloneableSerializable
implements Summarizer<WeightedValue<RingType>, RingType>
{
/**
* Creates a new instance of WeightedRingAverager
*/
public WeightedRingAverager()
{
}
public RingType summarize(
Collection<? extends WeightedValue<RingType>> data)
{
double weightSum = 0.0;
RingAccumulator<RingType> weightedSum =
new RingAccumulator<RingType>();
for( WeightedValue<RingType> value : data )
{
final double w = value.getWeight();
weightSum += w;
weightedSum.accumulate( value.getValue().scale( w ) );
}
return weightedSum.getSum().scale( 1.0/weightSum );
}
}