Package org.apache.commons.math4.stat.descriptive.moment

Class GeometricMean

java.lang.Object
org.apache.commons.math4.stat.descriptive.AbstractStorelessUnivariateStatistic
org.apache.commons.math4.stat.descriptive.moment.GeometricMean
All Implemented Interfaces:
java.io.Serializable, StorelessUnivariateStatistic, UnivariateStatistic, MathArrays.Function
public class GeometricMean
extends AbstractStorelessUnivariateStatistic
implements java.io.Serializable
Returns the geometric mean of the available values.

Uses a SumOfLogs instance to compute sum of logs and returns exp( 1/n (sum of 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 0.
  • 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.

See Also:
Serialized Form

  • Constructor Summary

    Constructors 
    Constructor Description
    GeometricMean()
    Create a GeometricMean instance.
    GeometricMean​(GeometricMean original)
    Copy constructor, creates a new GeometricMean identical to the original.
    GeometricMean​(SumOfLogs sumOfLogs)
    Create a GeometricMean instance using the given SumOfLogs instance

  • Method Summary

    Modifier and Type Method Description
    void clear()
    Clears the internal state of the Statistic
    GeometricMean copy()
    Returns a copy of the statistic with the same internal state.
    static void copy​(GeometricMean source, GeometricMean dest)
    Copies source to dest.
    double evaluate​(double[] values, int begin, int length)
    Returns the geometric mean of the entries in the specified portion of the input array.
    long getN()
    Returns the number of values that have been added.
    double getResult()
    Returns the current value of the Statistic.
    StorelessUnivariateStatistic getSumLogImpl()
    Returns the currently configured sum of logs implementation.
    void increment​(double d)
    Updates the internal state of the statistic to reflect the addition of the new value.
    void setSumLogImpl​(StorelessUnivariateStatistic sumLogImpl)
    Sets the implementation for the sum of logs.

    Methods inherited from class org.apache.commons.math4.stat.descriptive.AbstractStorelessUnivariateStatistic

    equals, evaluate, hashCode, incrementAll, incrementAll

    Methods inherited from class java.lang.Object

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