Package org.apache.commons.math3.util

Class RandomPivotingStrategy

java.lang.Object
org.apache.commons.math3.util.RandomPivotingStrategy
All Implemented Interfaces:
Serializable, PivotingStrategyInterface
public class RandomPivotingStrategy extends Object implements PivotingStrategyInterface, Serializable
A strategy of selecting random index between begin and end indices.
Since:
3.4
See Also:

  • Constructor Details

    • RandomPivotingStrategy

      public RandomPivotingStrategy(RandomGenerator random)
      Simple constructor.
      Parameters:
      random - random generator to use for selecting pivot

  • Method Details

    • pivotIndex

      public int pivotIndex(double[] work, int begin, int end) throws MathIllegalArgumentException
      Find pivot index of the array so that partition and Kth 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