Package org.hipparchus.util

Enum PivotingStrategy

java.lang.Object

java.lang.Enum<PivotingStrategy>

org.hipparchus.util.PivotingStrategy

All Implemented Interfaces:

Serializable, Comparable<PivotingStrategy>

public enum PivotingStrategy
extends Enum<PivotingStrategy>

A strategy to pick a pivoting index of an array for doing partitioning.

Enum Constant Summary

Enum Constants

Enum Constant	Description
CENTRAL	A mid point strategy based on the average of begin and end indices.
MEDIAN_OF_3	Classic median of 3 strategy given begin and end indices.

Method Summary

Modifier and Type	Method	Description
abstract int	pivotIndex(double[] work, int begin, int end)	Find pivot index of the array so that partition and Kth element selection can be made
static PivotingStrategy	valueOf(String name)	Returns the enum constant of this type with the specified name.
static PivotingStrategy[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

CENTRAL

public static final PivotingStrategy CENTRAL

A mid point strategy based on the average of begin and end indices.

MEDIAN_OF_3

public static final PivotingStrategy MEDIAN_OF_3

Classic median of 3 strategy given begin and end indices.

Method Detail

values

public static PivotingStrategy[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (PivotingStrategy c : PivotingStrategy.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static PivotingStrategy valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

pivotIndex

public abstract 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

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 of the pivot element chosen between the first and the last element of the array slice

Throws:

MathIllegalArgumentException - when indices exceeds range