/*
* Java Genetic Algorithm Library (@__identifier__@).
* Copyright (c) @__year__@ Franz Wilhelmstötter
*
* 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.
*
* Author:
* Franz Wilhelmstötter (franz.wilhelmstoetter@gmx.at)
*/
package org.jenetics.example;
import static org.jenetics.engine.EvolutionResult.toBestPhenotype;
import java.util.stream.IntStream;
import org.jenetics.CharacterChromosome;
import org.jenetics.CharacterGene;
import org.jenetics.Genotype;
import org.jenetics.Mutator;
import org.jenetics.Phenotype;
import org.jenetics.SinglePointCrossover;
import org.jenetics.StochasticUniversalSelector;
import org.jenetics.TournamentSelector;
import org.jenetics.engine.Engine;
import org.jenetics.util.CharSeq;
import org.jenetics.util.Factory;
/**
* @author <a href="mailto:franz.wilhelmstoetter@gmx.at">Franz Wilhelmstötter</a>
* @since 1.0
* @version 3.5
*/
public class StringGenerator {
private static final String TARGET_STRING = "jenetics";
private static Integer evaluate(final Genotype<CharacterGene> gt) {
final CharSequence source = (CharSequence)gt.getChromosome();
return IntStream.range(0, TARGET_STRING.length())
.map(i -> source.charAt(i) == TARGET_STRING.charAt(i) ? 1 : 0)
.sum();
}
public static void main(String[] args) throws Exception {
final CharSeq chars = CharSeq.of("a-z");
final Factory<Genotype<CharacterGene>> gtf = Genotype.of(
new CharacterChromosome(chars, TARGET_STRING.length())
);
final Engine<CharacterGene, Integer> engine = Engine
.builder(StringGenerator::evaluate, gtf)
.populationSize(500)
.survivorsSelector(new StochasticUniversalSelector<>())
.offspringSelector(new TournamentSelector<>(5))
.alterers(
new Mutator<>(0.1),
new SinglePointCrossover<>(0.5))
.build();
final Phenotype<CharacterGene, Integer> result = engine.stream()
.limit(100)
.collect(toBestPhenotype());
System.out.println(result);
}
}