Module io.jenetics.base
Package io.jenetics.stat

Class IntMomentStatistics

java.lang.Object
io.jenetics.stat.IntMomentStatistics
All Implemented Interfaces:
IntConsumer
public class IntMomentStatistics extends Object implements IntConsumer
A state object for collecting statistics such as count, min, max, sum, mean, variance, skewness and kurtosis. The design of this class is similar to the design of the IntSummaryStatistics class.

This class is designed to work with (though does not require) streams. For example, you can compute moments-statistics on a stream of ints with: 

final IntStream stream = ...;
final IntMomentStatistics statistics = stream.collect(
        IntMomentStatistics::new,
        IntMomentStatistics::accept,
        IntMomentStatistics::combine
    );
For a non-int stream, you can use a collector: 
final Stream<SomeObject> stream = ...;
final IntMomentStatistics statistics = stream
    .collect(toIntMomentStatistics(v -> v.intValue()));
Since:
3.0
Version:
6.0
See Also:
Implementation Note:
This implementation is not thread safe. However, it is safe to use toIntMomentStatistics(ToIntFunction) on a parallel stream, because the parallel implementation of Stream.collect() provides the necessary partitioning, isolation, and merging of results for safe and efficient parallel execution.

  • Constructor Summary

    Constructors
    Constructor
    Description
    IntMomentStatistics()
    Create an empty moments object.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    accept(int value)
    Records a new value into the moment information
    IntMomentStatistics
    combine(IntMomentStatistics other)
    Combine two IntMoments statistic objects.
    long
    count()
    Returns the count of values recorded.
    double
    kurtosis()
    Return the kurtosis of values recorded, or Double.NaN if less than four values have been recorded.
    int
    max()
    Return the maximum value recorded, or Integer.MIN_VALUE if no values have been recorded.
    double
    mean()
    Return the arithmetic mean of values recorded, or Double.NaN if no values have been recorded.
    int
    min()
    Return the minimum value recorded, or Integer.MAX_VALUE if no values have been recorded.
    boolean
    sameState(IntMomentStatistics other)
    Compares the state of two IntMomentStatistics objects.
    double
    skewness()
    Return the skewness of values recorded, or Double.NaN if less than two values have been recorded.
    long
    sum()
    Return the sum of values recorded, or zero if no values have been recorded.
    IntMoments
    toIntMoments()
    Return an IntMoments object from the current statistics,
    static <T> Collector<T,?,IntMomentStatistics>
    toIntMomentStatistics(ToIntFunction<? super T> mapper)
    Return a Collector which applies an int-producing mapping function to each input element, and returns moments-statistics for the resulting values.
    String
    toString()
     
    double
    variance()
    Return the variance of values recorded, or Double.NaN if no values have been recorded.

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface java.util.function.IntConsumer

    andThen

  • Constructor Details

  • Method Details

    • accept

      public void accept(int value)
      Records a new value into the moment information
      Specified by:
      accept in interface IntConsumer
      Parameters:
      value - the input value

    • combine

      public IntMomentStatistics combine(IntMomentStatistics other)
      Combine two IntMoments statistic objects.
      Parameters:
      other - the other IntMoments statistics to combine with this one.
      Returns:
      this statistics object
      Throws:
      NullPointerException - if the other statistical summary is null.

    • min

      public int min()
      Return the minimum value recorded, or Integer.MAX_VALUE if no values have been recorded.
      Returns:
      the minimum value, or Integer.MAX_VALUE if none

    • max

      public int max()
      Return the maximum value recorded, or Integer.MIN_VALUE if no values have been recorded.
      Returns:
      the maximum value, or Integer.MIN_VALUE if none

    • sum

      public long sum()
      Return the sum of values recorded, or zero if no values have been recorded.
      Returns:
      the sum of values, or zero if none

    • sameState

      public boolean sameState(IntMomentStatistics other)
      Compares the state of two IntMomentStatistics objects. This is a replacement for the Object.equals(Object) which is not advisable to implement for this mutable object. If two objects have the same state, it has still the same state when updated with the same value. 
      final IntMomentStatistics ims1 = ...;
final IntMomentStatistics ims2 = ...;

if (ims1.sameState(ims2)) {
    final int value = random.nextInt(1_000_000);
    ims1.accept(value);
    ims2.accept(value);

    assert ims1.sameState(ims2);
    assert ims2.sameState(ims1);
    assert ims1.sameState(ims1);
}
      Parameters:
      other - the other object for the test
      Returns:
      true the this and the other objects have the same state, false otherwise
      Since:
      3.7

    • toIntMoments

      public IntMoments toIntMoments()
      Return an IntMoments object from the current statistics,
      Returns:
      an IntMoments object from the current statistics
      Since:
      3.9

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • toIntMomentStatistics

      public static <T> Collector<T,?,IntMomentStatistics> toIntMomentStatistics(ToIntFunction<? super T> mapper)
      Return a Collector which applies an int-producing mapping function to each input element, and returns moments-statistics for the resulting values. 
      final Stream<SomeObject> stream = ...;
final IntMomentStatistics statistics = stream
    .collect(toIntMomentStatistics(v -> v.intValue()));
      Type Parameters:
      T - the type of the input elements
      Parameters:
      mapper - a mapping function to apply to each element
      Returns:
      a Collector implementing the moments-statistics reduction
      Throws:
      NullPointerException - if the given mapper is null

    • count

      public long count()
      Returns the count of values recorded.
      Returns:
      the count of recorded values

    • mean

      public double mean()
      Return the arithmetic mean of values recorded, or Double.NaN if no values have been recorded.
      Returns:
      the arithmetic mean of values, or zero if none

    • variance

      public double variance()
      Return the variance of values recorded, or Double.NaN if no values have been recorded.
      Returns:
      the variance of values, or NaN if none

    • skewness

      public double skewness()
      Return the skewness of values recorded, or Double.NaN if less than two values have been recorded.
      Returns:
      the skewness of values, or NaN if less than two values have been recorded
      See Also:

    • kurtosis

      public double kurtosis()
      Return the kurtosis of values recorded, or Double.NaN if less than four values have been recorded.
      Returns:
      the kurtosis of values, or NaN if less than four values have been recorded
      See Also: