net.imglib2.util

Class RealSum

java.lang.Object

net.imglib2.util.RealSum

public class RealSum
extends Object

RealSum implements a method to reduce numerical instabilities when summing up a very large number of double precision numbers. Numerical problems occur when a small number is added to an already very large sum. In such case, the reduced accuracy of the very large number may lead to the small number being entirely ignored. The method here is Neumaier's improvement of the Kahan summation algorithm. See this Wikipedia article for details.

Author:

Michael Innerberger, Stephan Saalfeld

Constructor Summary

Constructors

Constructor and Description
RealSum() Create a new RealSum initialized to zero.
RealSum(int capacity) Deprecated.

Method Summary

Modifier and Type	Method and Description
void	add(double value) Add an element to the sum.
double	getSum() Get the current sum.

Methods inherited from class java.lang.Object

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

Constructor Detail

RealSum

public RealSum()

Create a new RealSum initialized to zero.

RealSum

@Deprecated
public RealSum(int capacity)

Deprecated.

Create a new RealSum initialized to zero. This constructor was used in a previous version of RealSum and is kept for backwards compatibility.

Parameters:

capacity - unused

Method Detail

getSum

public double getSum()

Get the current sum.

add

public void add(double value)

Add an element to the sum.

Parameters:

value - the summand to be added