TournamentSelection (Apache Commons Math 4.0-beta1)

java.lang.Object
- org.apache.commons.math4.legacy.genetics.TournamentSelection

All Implemented Interfaces:

SelectionPolicy
```
public class TournamentSelection
extends Object
implements SelectionPolicy
```
Tournament selection scheme. Each of the two selected chromosomes is selected based on n-ary tournament -- this is done by drawing arity random chromosomes without replacement from the population, and then selecting the fittest chromosome among them.

Since:

2.0

Constructor Summary

Constructors
Constructor Description

TournamentSelection(int arity)
Creates a new TournamentSelection instance.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`getArity()`	Gets the arity (number of chromosomes drawn to the tournament).
`ChromosomePair`	`select(Population population)`	Select two chromosomes from the population.
`void`	`setArity(int arity)`	Sets the arity (number of chromosomes drawn to the tournament).

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

- Constructor Detail
  - TournamentSelection
```
public TournamentSelection(int arity)
```
    Creates a new TournamentSelection instance.
    
    Parameters:
    
    arity - how many chromosomes will be drawn to the tournament
- Method Detail
  - select
```
public ChromosomePair select(Population population)
                      throws MathIllegalArgumentException
```
    Select two chromosomes from the population. Each of the two selected chromosomes is selected based on n-ary tournament -- this is done by drawing arity random chromosomes without replacement from the population, and then selecting the fittest chromosome among them.
    
    Specified by:
    
    select in interface SelectionPolicy
    
    Parameters:
    
    population - the population from which the chromosomes are chosen.
    
    Returns:
    
    the selected chromosomes.
    
    Throws:
    
    MathIllegalArgumentException - if the tournament arity is bigger than the population size
  - getArity
```
public int getArity()
```
    Gets the arity (number of chromosomes drawn to the tournament).
    
    Returns:
    
    arity of the tournament
  - setArity
```
public void setArity(int arity)
```
    Sets the arity (number of chromosomes drawn to the tournament).
    
    Parameters:
    
    arity - arity of the tournament