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//=============================================================================
// Copyright 2006-2010 Daniel W. Dyer
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//=============================================================================
package org.uncommons.watchmaker.framework;
import java.util.List;
import java.util.Random;
/**
* Strategy interface for "natural" selection.
* @param The type of evolved entity that we are selecting.
* @author Daniel Dyer
*/
public interface SelectionStrategy
{
/**
* Select the specified number of candidates from the population.
* Implementations may assume that the population is sorted in descending
* order according to fitness (so the fittest individual is the first item
* in the list).
* It is an error to call this method with an empty or null population.
* @param The type of evolved entity that we are selecting, a sub-type of T.
* @param population The population from which to select.
* @param naturalFitnessScores Whether higher fitness values represent fitter
* individuals or not.
* @param selectionSize The number of individual selections to make (not necessarily
* the number of distinct candidates to select, since the same individual may
* potentially be selected more than once).
* @param rng Source of randomness for stochastic selection strategies.
* @return A list containing the selected candidates. Some individual canidates may
* potentially have been selected multiple times.
*/
List select(List> population,
boolean naturalFitnessScores,
int selectionSize,
Random rng);
}