RandomPivotingStrategy (VirtualDataSet API)

java.lang.Object
- org.apache.commons.math4.util.RandomPivotingStrategy

All Implemented Interfaces:

java.io.Serializable, PivotingStrategyInterface
```
public class RandomPivotingStrategy
extends java.lang.Object
implements PivotingStrategyInterface, java.io.Serializable
```
A strategy of selecting random index between begin and end indices.

Since:

3.4

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor Description

RandomPivotingStrategy(RandomSource randomSource, long seed)
Simple constructor.

Method Summary

Modifier and Type	Method	Description
`int`	`pivotIndex(double[] work, int begin, int end)`	Find pivot index of the array so that partition and K^th element selection can be made

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

- Constructor Detail
  - RandomPivotingStrategy
```
public RandomPivotingStrategy(RandomSource randomSource,
                              long seed)
```
    Simple constructor.
    
    Parameters:
    
    randomSource - RNG to use for selecting pivot.
    
    seed - Seed for initializing the RNG.
    
    Since:
    
    4.0
- Method Detail
  - pivotIndex
```
public int pivotIndex(double[] work,
                      int begin,
                      int end)
               throws MathIllegalArgumentException
```
    Find pivot index of the array so that partition and K^th element selection can be made A uniform random pivot selection between begin and end indices.
    
    Specified by:
    
    pivotIndex in interface PivotingStrategyInterface
    
    Parameters:
    
    work - data array
    
    begin - index of the first element of the slice
    
    end - index after the last element of the slice
    
    Returns:
    
    The index corresponding to a random uniformly selected value between first and the last indices of the array slice
    
    Throws:
    
    MathIllegalArgumentException - when indices exceeds range