public static void main(String[] args) {
final Engine<DoubleGene, Double> engine =
Engine
// Create a new builder with the given fitness
// function and chromosome.
.builder(RealFunction::eval, DoubleChromosome.of(0.0, 2.0 * PI))
.populationSize(500)
.optimize(Optimize.MINIMUM)
.alterers(new Mutator<>(0.03), new MeanAlterer<>(0.6))
// Build an evolution engine with the
// defined parameters.
.build();
// Create evolution statistics consumer.
final EvolutionStatistics<Double, ?> statistics = EvolutionStatistics.ofNumber();
final Phenotype<DoubleGene, Double> best =
engine
.stream()
// Truncate the evolution stream after 7 "steady"
// generations.
.limit(bySteadyFitness(7))
// The evolution will stop after maximal 100
// generations.
.limit(100)
// Update the evaluation statistics after
// each generation
.peek(statistics)
// Collect (reduce) the evolution stream to
// its best phenotype.
.collect(toBestPhenotype());
System.out.println(statistics);
System.out.println(best);
}
private static Phenotype<DoubleGene, Double> phenotype(final double value) {
return Phenotype.of(
Genotype.of(DoubleChromosome.of(DoubleGene.of(value, 0.0, 1000.0))),
1,
a -> a.getGene().getAllele());
}