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

Class Product

java.lang.Object
org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic
org.apache.commons.math3.stat.descriptive.AbstractStorelessUnivariateStatistic
org.apache.commons.math3.stat.descriptive.summary.Product
All Implemented Interfaces:
Serializable, StorelessUnivariateStatistic, UnivariateStatistic, WeightedEvaluation, MathArrays.Function
public class Product extends AbstractStorelessUnivariateStatistic implements Serializable, WeightedEvaluation
Returns the product of the available values.

If there are no values in the dataset, then 1 is returned. If any of the values are NaN, then NaN is returned.

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:

  • Constructor Summary

    Constructors
    Constructor
    Description
    Product()
    Create a Product instance
    Product(Product original)
    Copy constructor, creates a new Product identical to the original

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    clear()
    Clears the internal state of the Statistic
    Product
    copy()
    Returns a copy of the statistic with the same internal state.
    static void
    copy(Product source, Product dest)
    Copies source to dest.
    double
    evaluate(double[] values, double[] weights)
    Returns the weighted product of the entries in the input array.
    double
    evaluate(double[] values, double[] weights, int begin, int length)
    Returns the weighted product of the entries in the specified portion of the input array, or Double.NaN if the designated subarray is empty.
    double
    evaluate(double[] values, int begin, int length)
    Returns the product 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.

    Methods inherited from class org.apache.commons.math3.stat.descriptive.AbstractStorelessUnivariateStatistic

    equals, evaluate, hashCode, incrementAll, incrementAll

    Methods inherited from class org.apache.commons.math3.stat.descriptive.AbstractUnivariateStatistic

    evaluate, getData, getDataRef, setData, setData, test, test, test, test

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Product

      public Product()
      Create a Product instance

    • Product

      public Product(Product original) throws NullArgumentException
      Copy constructor, creates a new Product identical to the original
      Parameters:
      original - the Product instance to copy
      Throws:
      NullArgumentException - if original is null

  • Method Details

    • increment

      public void increment(double d)
      Updates the internal state of the statistic to reflect the addition of the new value.
      Specified by:
      increment in interface StorelessUnivariateStatistic
      Specified by:
      increment in class AbstractStorelessUnivariateStatistic
      Parameters:
      d - the new value.

    • getResult

      public double getResult()
      Returns the current value of the Statistic.
      Specified by:
      getResult in interface StorelessUnivariateStatistic
      Specified by:
      getResult in class AbstractStorelessUnivariateStatistic
      Returns:
      value of the statistic, Double.NaN if it has been cleared or just instantiated.

    • getN

      public long getN()
      Returns the number of values that have been added.
      Specified by:
      getN in interface StorelessUnivariateStatistic
      Returns:
      the number of values.

    • clear

      public void clear()
      Clears the internal state of the Statistic
      Specified by:
      clear in interface StorelessUnivariateStatistic
      Specified by:
      clear in class AbstractStorelessUnivariateStatistic

    • evaluate

      public double evaluate(double[] values, int begin, int length) throws MathIllegalArgumentException
      Returns the product of the entries in the specified portion of the input array, or Double.NaN if the designated subarray is empty.

      Throws MathIllegalArgumentException if the array is null.

      Specified by:
      evaluate in interface MathArrays.Function
      Specified by:
      evaluate in interface UnivariateStatistic
      Overrides:
      evaluate in class AbstractStorelessUnivariateStatistic
      Parameters:
      values - the input array
      begin - index of the first array element to include
      length - the number of elements to include
      Returns:
      the product of the values or 1 if length = 0
      Throws:
      MathIllegalArgumentException - if the array is null or the array index parameters are not valid
      See Also:

    • evaluate

      public double evaluate(double[] values, double[] weights, int begin, int length) throws MathIllegalArgumentException

      Returns the weighted product of the entries in the specified portion of the input array, or Double.NaN if the designated subarray is empty.

      Throws MathIllegalArgumentException if any of the following are true:

      • the values array is null
      • the weights array is null
      • the weights array does not have the same length as the values array
      • the weights array contains one or more infinite values
      • the weights array contains one or more NaN values
      • the weights array contains negative values
      • the start and length arguments do not determine a valid array

      Uses the formula, 

          weighted product = ∏values[i]weights[i]
      that is, the weights are applied as exponents when computing the weighted product.

      Specified by:
      evaluate in interface WeightedEvaluation
      Parameters:
      values - the input array
      weights - the weights array
      begin - index of the first array element to include
      length - the number of elements to include
      Returns:
      the product of the values or 1 if length = 0
      Throws:
      MathIllegalArgumentException - if the parameters are not valid
      Since:
      2.1

    • evaluate

      public double evaluate(double[] values, double[] weights) throws MathIllegalArgumentException

      Returns the weighted product of the entries in the input array.

      Throws MathIllegalArgumentException if any of the following are true:

      • the values array is null
      • the weights array is null
      • the weights array does not have the same length as the values array
      • the weights array contains one or more infinite values
      • the weights array contains one or more NaN values
      • the weights array contains negative values

      Uses the formula, 

          weighted product = ∏values[i]weights[i]
      that is, the weights are applied as exponents when computing the weighted product.

      Specified by:
      evaluate in interface WeightedEvaluation
      Parameters:
      values - the input array
      weights - the weights array
      Returns:
      the product of the values or Double.NaN if length = 0
      Throws:
      MathIllegalArgumentException - if the parameters are not valid
      Since:
      2.1

    • copy

      public Product copy()
      Returns a copy of the statistic with the same internal state.
      Specified by:
      copy in interface StorelessUnivariateStatistic
      Specified by:
      copy in interface UnivariateStatistic
      Specified by:
      copy in class AbstractStorelessUnivariateStatistic
      Returns:
      a copy of the statistic

    • copy

      public static void copy(Product source, Product dest) throws NullArgumentException
      Copies source to dest.

      Neither source nor dest can be null.

      Parameters:
      source - Product to copy
      dest - Product to copy to
      Throws:
      NullArgumentException - if either source or dest is null