org.apache.commons.math3.stat.descriptive

## Interface StorelessUnivariateStatistic

- All Superinterfaces:
    MathArrays.Function, UnivariateStatistic
  All Known Implementing Classes:
    AbstractStorelessUnivariateStatistic, FirstMoment, FourthMoment, GeometricMean, Kurtosis, Max, Mean, Min, Product, SecondMoment, Skewness, StandardDeviation, Sum, SumOfLogs, SumOfSquares, ThirdMoment, Variance

      public interface StorelessUnivariateStatistic
      extends UnivariateStatistic

  Extends the definition of `UnivariateStatistic` with `increment(double)` and `incrementAll(double[])` methods for adding values and updating internal state.

  This interface is designed to be used for calculating statistics that can be computed in one pass through the data without storing the full array of sample values.

  Version:
    $Id: StorelessUnivariateStatistic.java 1416643 2012-12-03 19:37:14Z tn $

- - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `clear()` Clears the internal state of the Statistic
    `StorelessUnivariateStatistic` | `copy()` Returns a copy of the statistic with the same internal state.
    `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.
    `void` | `incrementAll(double[] values)` Updates the internal state of the statistic to reflect addition of all values in the values array.
    `void` | `incrementAll(double[] values, int start, int length)` Updates the internal state of the statistic to reflect addition of the values in the designated portion of the values array.

    - ### Methods inherited from interface org.apache.commons.math3.stat.descriptive.UnivariateStatistic

      `evaluate, evaluate`

- - ### Method Detail

    - #### increment

          void increment(double d)

      Updates the internal state of the statistic to reflect the addition of the new value.
      Parameters:
        `d` - the new value.

    - #### incrementAll

          void incrementAll(double[] values)
                            throws MathIllegalArgumentException

      Updates the internal state of the statistic to reflect addition of all values in the values array. Does not clear the statistic first -- i.e., the values are added incrementally to the dataset.
      Parameters:
        `values` - array holding the new values to add
      Throws:
        `MathIllegalArgumentException` - if the array is null

    - #### incrementAll

          void incrementAll(double[] values,
                          int start,
                          int length)
                            throws MathIllegalArgumentException

      Updates the internal state of the statistic to reflect addition of the values in the designated portion of the values array. Does not clear the statistic first -- i.e., the values are added incrementally to the dataset.
      Parameters:
        `values` - array holding the new values to add
        `start` - the array index of the first value to add
        `length` - the number of elements to add
      Throws:
        `MathIllegalArgumentException` - if the array is null or the index

    - #### getResult

          double getResult()

      Returns the current value of the Statistic.
      Returns:
        value of the statistic, `Double.NaN` if it has been cleared or just instantiated.

    - #### getN

          long getN()

      Returns the number of values that have been added.
      Returns:
        the number of values.

    - #### clear

          void clear()

      Clears the internal state of the Statistic

    - #### copy

          StorelessUnivariateStatistic copy()

      Returns a copy of the statistic with the same internal state.
      Specified by:
        `copy` in interface `UnivariateStatistic`
      Returns:
        a copy of the statistic

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