Product (Apache Commons Math 3.6.1 API)

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:
Serialized Form

Constructor Summary

Constructors
Constructor and Description

Product()
Create a Product instance

Product(Product original)
Copy constructor, creates a new Product identical to the original

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

Method Summary

Methods
Modifier and Type	Method and 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 Detail
  - 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 Detail
  - 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 UnivariateStatistic
    
    Specified by:
    
    evaluate in interface MathArrays.Function
    
    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:
    UnivariateStatistic.evaluate(double[], int, int)
  - 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

Class Product

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

Constructor Detail

Product

Product

Method Detail

increment

getResult

getN

clear

evaluate

evaluate

evaluate

copy

copy