KthSelector (nosqlbench)

java.lang.Object

org.apache.commons.math4.util.KthSelector

All Implemented Interfaces:: java.io.Serializable

public class KthSelector
extends java.lang.Object
implements java.io.Serializable

A Simple K^th selector implementation to pick up the K^th ordered element from a work array containing the input numbers.

Since:: 3.4
See Also:: Serialized Form

Constructor Summary

Constructors
Constructor	Description
`KthSelector()`	Constructor with default `median of 3` pivoting strategy
`KthSelector(PivotingStrategyInterface pivotingStrategy)`	Constructor with specified pivoting strategy

Method Summary

Modifier and Type	Method	Description
`PivotingStrategyInterface`	`getPivotingStrategy()`	Get the pivotin strategy.
`double`	`select(double[] work, int[] pivotsHeap, int k)`	Select K^th value in the array.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details
- KthSelector
  
  public KthSelector()
  
  Constructor with default median of 3 pivoting strategy
- KthSelector
  
  public KthSelector(PivotingStrategyInterface pivotingStrategy) throws NullArgumentException
  
  Constructor with specified pivoting strategy
  
  Parameters:
  
  pivotingStrategy - pivoting strategy to use
  
  Throws:
  
  NullArgumentException - when pivotingStrategy is null
  
  See Also:
  
  MedianOf3PivotingStrategy, RandomPivotingStrategy, CentralPivotingStrategy
Method Details
- getPivotingStrategy
  
  public PivotingStrategyInterface getPivotingStrategy()
  
  Get the pivotin strategy.
  
  Returns:
  
  pivoting strategy
- select
  
  public double select(double[] work, int[] pivotsHeap, int k)
  
  Select K^th value in the array.
  
  Parameters:
  
  work - work array to use to find out the K^th value
  
  pivotsHeap - cached pivots heap that can be used for efficient estimation
  
  k - the index whose value in the array is of interest
  
  Returns:
  
  K^th value