DoubleMomentStatistics (Jenetics 3.8.0)

java.lang.Object
- org.jenetics.stat.DoubleMomentStatistics

All Implemented Interfaces:

DoubleConsumer
```
public class DoubleMomentStatistics
extends Object
implements DoubleConsumer
```
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 DoubleSummaryStatistics class.
This class is designed to work with (though does not require) streams. For example, you can compute moments-statistics on a stream of doubles with:
final DoubleStream stream = ... final DoubleMomentStatistics statistics = stream.collect( DoubleMomentStatistics::new, DoubleMomentStatistics::accept, DoubleMomentStatistics::combine );
For a non double stream, you can use a collector:
final Stream<SomeObject> stream = ... final DoubleMomentStatistics statistics = stream .collect(toDoubleMomentStatistics(v -> v.doubleValue()));

Implementation note: This implementation is not thread safe. However, it is safe to use toDoubleMomentStatistics(ToDoubleFunction) 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.

Since:

3.0

Version:

3.7

Author:

Franz Wilhelmstötter

See Also:

DoubleSummaryStatistics, DoubleMoments, Computing Higher-Order Moments Online

Constructor Summary

Constructors
Constructor and Description

DoubleMomentStatistics()
Create an empty moments object.

Constructors
Constructor and Description
`DoubleMomentStatistics()` Create an empty moments object.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`accept(double value)` Records a new value into the moments information
`DoubleMomentStatistics`	`combine(DoubleMomentStatistics other)` Combine two `DoubleMoments` statistic objects.
`long`	`getCount()` Returns the count of values recorded.
`double`	`getKurtosis()` Return the kurtosis of values recorded, or `Double.NaN` if less than four values have been recorded.
`double`	`getMax()` Return the maximum value recorded, or `Double.NEGATIVE_INFINITY` if no values have been recorded.
`double`	`getMean()` Return the arithmetic mean of values recorded, or `Double.NaN` if no values have been recorded.
`double`	`getMin()` Return the minimum value recorded, or `Double.POSITIVE_INFINITY` if no values have been recorded.
`double`	`getSkewness()` Return the skewness of values recorded, or `Double.NaN` if less than two values have been recorded.
`double`	`getSum()` Return the sum of values recorded, or zero if no values have been recorded.
`double`	`getVariance()` Return the variance of values recorded, or `Double.NaN` if no values have been recorded.
`boolean`	`sameState(DoubleMomentStatistics other)` Compares the state of two `DoubleMomentStatistics` objects.
`static <T> Collector<T,?,DoubleMomentStatistics>`	`toDoubleMomentStatistics(ToDoubleFunction<? super T> mapper)` Return a `Collector` which applies an double-producing mapping function to each input element, and returns moments-statistics for the resulting values.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.function.DoubleConsumer
andThen

- Constructor Detail
  - DoubleMomentStatistics
```
public DoubleMomentStatistics()
```
    Create an empty moments object.
- Method Detail
  - accept
```
public void accept(double value)
```
    Records a new value into the moments information
    
    Specified by:
    
    accept in interface DoubleConsumer
    
    Parameters:
    
    value - the input value
  - combine
```
public DoubleMomentStatistics combine(DoubleMomentStatistics other)
```
    Combine two DoubleMoments statistic objects.
    
    Parameters:
    
    other - the other DoubleMoments statistics to combine with this one.
    
    Returns:
    
    this statistics object
    
    Throws:
    
    NullPointerException - if the other statistical summary is null.
  - getMin
```
public double getMin()
```
    Return the minimum value recorded, or Double.POSITIVE_INFINITY if no values have been recorded.
    
    Returns:
    
    the minimum value, or Double.POSITIVE_INFINITY if none
  - getMax
```
public double getMax()
```
    Return the maximum value recorded, or Double.NEGATIVE_INFINITY if no values have been recorded.
    
    Returns:
    
    the maximum value, or Double.NEGATIVE_INFINITY if none
  - getSum
```
public double getSum()
```
    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(DoubleMomentStatistics other)
```
    Compares the state of two DoubleMomentStatistics objects. This is a replacement for the Object.equals(Object) which is not advisable to implement for this mutable object. If two object have the same state, it has still the same state when updated with the same value.
    final DoubleMomentStatistics ds1 = ...; final DoubleMomentStatistics ds2 = ...; if (ds1.sameState(ds2)) { final double value = random.nextDouble(); ds1.accept(value); ds2.accept(value); assert ds1.sameState(ds2); assert ds2.sameState(ds1); assert ds1.sameState(ds1); }
    
    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
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - toDoubleMomentStatistics
```
public static <T> Collector<T,?,DoubleMomentStatistics> toDoubleMomentStatistics(ToDoubleFunction<? super T> mapper)
```
    Return a Collector which applies an double-producing mapping function to each input element, and returns moments-statistics for the resulting values.
    final Stream<SomeObject> stream = ... final DoubleMomentStatistics statistics = stream .collect(toDoubleMomentStatistics(v -> v.doubleValue()));
    
    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
  - getCount
```
public long getCount()
```
    Returns the count of values recorded.
    
    Returns:
    
    the count of recorded values
  - getMean
```
public double getMean()
```
    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
  - getVariance
```
public double getVariance()
```
    Return the variance of values recorded, or Double.NaN if no values have been recorded.
    
    Returns:
    
    the variance of values, or NaN if none
  - getSkewness
```
public double getSkewness()
```
    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:
    
    Skewness
  - getKurtosis
```
public double getKurtosis()
```
    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:
    
    Kurtosis

Class DoubleMomentStatistics

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.function.DoubleConsumer

Constructor Detail

DoubleMomentStatistics

Method Detail

accept

combine

getMin

getMax

getSum

sameState

toString

toDoubleMomentStatistics

getCount

getMean

getVariance

getSkewness

getKurtosis