java.lang.Object
- org.apache.commons.math4.legacy.stat.descriptive.AbstractStorelessUnivariateStatistic
- - org.apache.commons.math4.legacy.stat.descriptive.summary.SumOfSquares

All Implemented Interfaces:

MathArrays.Function, StorelessUnivariateStatistic, UnivariateStatistic
```
public class SumOfSquares
extends AbstractStorelessUnivariateStatistic
```
Returns the sum of the squares of the available values.
If there are no values in the dataset, then 0 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.

Constructor Summary

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

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`clear()`	Clears the internal state of the Statistic.
`SumOfSquares`	`copy()`	Returns a copy of the statistic with the same internal state.
`static void`	`copy(SumOfSquares source, SumOfSquares dest)`	Copies source to dest.
`double`	`evaluate(double[] values, int begin, int length)`	Returns the sum of the squares 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.math4.legacy.stat.descriptive.AbstractStorelessUnivariateStatistic
equals, evaluate, hashCode, incrementAll, incrementAll

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

- Constructor Detail
  - SumOfSquares
```
public SumOfSquares()
```
    Create a SumOfSquares instance.
  - SumOfSquares
```
public SumOfSquares(SumOfSquares original)
             throws NullArgumentException
```
    Copy constructor, creates a new SumOfSquares identical to the original.
    
    Parameters:
    
    original - the SumOfSquares 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.
    
    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 sum of the squares 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 sum of the squares of the values or 0 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)
  - copy
```
public SumOfSquares 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(SumOfSquares source,
                        SumOfSquares dest)
                 throws NullArgumentException
```
    Copies source to dest.
    Neither source nor dest can be null.
    
    Parameters:
    
    source - SumOfSquares to copy
    
    dest - SumOfSquares to copy to
    
    Throws:
    
    NullArgumentException - if either source or dest is null

Class SumOfSquares

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.math4.legacy.stat.descriptive.AbstractStorelessUnivariateStatistic

Methods inherited from class java.lang.Object

Constructor Detail

SumOfSquares

SumOfSquares

Method Detail

increment

getResult

getN

clear

evaluate

copy

copy