org.apache.commons.math3.stat.descriptive.summary

## Class SumOfLogs

• All Implemented Interfaces:
Serializable, StorelessUnivariateStatistic, UnivariateStatistic, MathArrays.Function

public class SumOfLogs
extends AbstractStorelessUnivariateStatistic
implements Serializable
Returns the sum of the natural logs for this collection of values.

Uses FastMath.log(double) to compute the logs. Therefore,

• If any of values are < 0, the result is NaN.
• If all values are non-negative and less than Double.POSITIVE_INFINITY, but at least one value is 0, the result is Double.NEGATIVE_INFINITY.
• If both Double.POSITIVE_INFINITY and Double.NEGATIVE_INFINITY are among the values, the result is NaN.

Note that this implementation is not synchronized. If multiple threads access an instance of this class concurrently, and at least one of the threads invokes the increment() or clear() method, it must be synchronized externally.

Version:
$Id: SumOfLogs.java 1416643 2012-12-03 19:37:14Z tn$
Serialized Form
• ### Constructor Summary

Constructors
Constructor and Description
SumOfLogs()
Create a SumOfLogs instance
SumOfLogs(SumOfLogs original)
Copy constructor, creates a new SumOfLogs identical to the original
• ### Method Summary

Methods
Modifier and Type Method and Description
void clear()
Clears the internal state of the Statistic
SumOfLogs copy()
Returns a copy of the statistic with the same internal state.
static void copy(SumOfLogs source, SumOfLogs dest)
Copies source to dest.
double evaluate(double[] values, int begin, int length)
Returns the sum of the natural logs of the entries in the specified portion of the input array, or Double.NaN if the designated subarray is empty.
long getN()
Returns the number of values that have been added.
double getResult()
Returns the current value of the Statistic.
void increment(double d)
Updates the internal state of the statistic to reflect the addition of the new value.