All Implemented Interfaces:
Serializable, StorelessUnivariateStatistic, UnivariateStatistic

public class GeometricMean extends AbstractStorelessUnivariateStatistic implements 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 invalid input: '<' 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.

Version:
$Revision: 1006299 $ $Date: 2010-10-10 16:47:17 +0200 (dim. 10 oct. 2010) $
See Also:
  • Constructor Details

    • GeometricMean

      public GeometricMean()
      Create a GeometricMean instance
    • GeometricMean

      public GeometricMean(GeometricMean original)
      Copy constructor, creates a new GeometricMean identical to the original
      Parameters:
      original - the GeometricMean instance to copy
    • GeometricMean

      public GeometricMean(SumOfLogs sumOfLogs)
      Create a GeometricMean instance using the given SumOfLogs instance
      Parameters:
      sumOfLogs - sum of logs instance to use for computation
  • Method Details