Package org.hipparchus.stat.descriptive.summary

Class Product

java.lang.Object
org.hipparchus.stat.descriptive.AbstractStorelessUnivariateStatistic
org.hipparchus.stat.descriptive.summary.Product
All Implemented Interfaces:
Serializable, DoubleConsumer, AggregatableStatistic<Product>, StorelessUnivariateStatistic, UnivariateStatistic, WeightedEvaluation, MathArrays.Function
public class Product extends AbstractStorelessUnivariateStatistic implements AggregatableStatistic<Product>, WeightedEvaluation, Serializable
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
    aggregate(Product other)
    Aggregates the provided instance into this instance.
    void
    clear()
    Clears the internal state of the Statistic
    Product
    copy()
    Returns a copy of the statistic with the same internal state.
    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.hipparchus.stat.descriptive.AbstractStorelessUnivariateStatistic

    equals, hashCode, toString

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface org.hipparchus.stat.descriptive.AggregatableStatistic

    aggregate, aggregate

    Methods inherited from interface java.util.function.DoubleConsumer

    andThen

    Methods inherited from interface org.hipparchus.stat.descriptive.StorelessUnivariateStatistic

    accept, incrementAll, incrementAll

    Methods inherited from interface org.hipparchus.stat.descriptive.UnivariateStatistic

    evaluate

    Methods inherited from interface org.hipparchus.stat.descriptive.WeightedEvaluation

    evaluate

  • 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

    • aggregate

      public void aggregate(Product other)
      Aggregates the provided instance into this instance.

      This method can be used to combine statistics computed over partitions or subsamples - i.e., the value of this instance after this operation should be the same as if a single statistic would have been applied over the combined dataset.

      Specified by:
      aggregate in interface AggregatableStatistic<Product>
      Parameters:
      other - the instance to aggregate into this instance

    • 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.
      Specified by:
      evaluate in interface MathArrays.Function
      Specified by:
      evaluate in interface StorelessUnivariateStatistic
      Specified by:
      evaluate in interface UnivariateStatistic
      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 \(\mathrm{weighted product} = \prod \mathrm{values}_i^{\mathrm{weights}_i}\)

      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

    • 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