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Jenetics library (#1601)

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maibin 2017-04-10 05:19:49 +02:00 committed by KevinGilmore
parent cc276589ec
commit a826e70c23
10 changed files with 388 additions and 0 deletions
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1
algorithms/.gitignore vendored Normal file
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/target/

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algorithms/pom.xml
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<version>${lombok.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>io.jenetics</groupId>
<artifactId>jenetics</artifactId>
<version>3.7.0</version>
</dependency>
</dependencies>
<build>

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/Knapsack.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import static org.jenetics.engine.EvolutionResult.toBestPhenotype;
import static org.jenetics.engine.limit.bySteadyFitness;
import java.util.stream.Stream;
import org.jenetics.BitChromosome;
import org.jenetics.BitGene;
import org.jenetics.Mutator;
import org.jenetics.Phenotype;
import org.jenetics.RouletteWheelSelector;
import org.jenetics.SinglePointCrossover;
import org.jenetics.TournamentSelector;
import org.jenetics.engine.Engine;
import org.jenetics.engine.EvolutionStatistics;
//The main class.
public class Knapsack {
public static void main(String[] args) {
int nItems = 15;
double ksSize = nItems * 100.0 / 3.0;
KnapsackFF ff = new KnapsackFF(Stream.generate(KnapsackItem::random)
.limit(nItems)
.toArray(KnapsackItem[]::new), ksSize);
Engine<BitGene, Double> engine = Engine.builder(ff, BitChromosome.of(nItems, 0.5))
.populationSize(500)
.survivorsSelector(new TournamentSelector<>(5))
.offspringSelector(new RouletteWheelSelector<>())
.alterers(new Mutator<>(0.115), new SinglePointCrossover<>(0.16))
.build();
EvolutionStatistics<Double, ?> statistics = EvolutionStatistics.ofNumber();
Phenotype<BitGene, Double> best = engine.stream()
.limit(bySteadyFitness(7))
.limit(100)
.peek(statistics)
.collect(toBestPhenotype());
System.out.println(statistics);
System.out.println(best);
}
}

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/KnapsackFF.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import java.util.function.Function;
import org.jenetics.BitChromosome;
import org.jenetics.BitGene;
import org.jenetics.Genotype;
public class KnapsackFF implements Function<Genotype<BitGene>, Double> {
private KnapsackItem[] items;
private double size;
public KnapsackFF(KnapsackItem[] items, double size) {
this.items = items;
this.size = size;
}
@Override
public Double apply(Genotype<BitGene> gt) {
KnapsackItem sum = ((BitChromosome) gt.getChromosome()).ones()
.mapToObj(i -> items[i])
.collect(KnapsackItem.toSum());
return sum.size <= this.size ? sum.value : 0;
}
}

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/KnapsackItem.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import java.util.Random;
import java.util.stream.Collector;
import org.jenetics.util.RandomRegistry;
public class KnapsackItem {
public double size;
public double value;
public KnapsackItem(double size, double value) {
this.size = size;
this.value = value;
}
protected static KnapsackItem random() {
Random r = RandomRegistry.getRandom();
return new KnapsackItem(r.nextDouble() * 100, r.nextDouble() * 100);
}
protected static Collector<KnapsackItem, ?, KnapsackItem> toSum() {
return Collector.of(() -> new double[2], (a, b) -> {
a[0] += b.size;
a[1] += b.value;
} , (a, b) -> {
a[0] += b[0];
a[1] += b[1];
return a;
} , r -> new KnapsackItem(r[0], r[1]));
}
}

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/SimpleGeneticAlgorithm.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import org.jenetics.BitChromosome;
import org.jenetics.BitGene;
import org.jenetics.Genotype;
import org.jenetics.engine.Engine;
import org.jenetics.engine.EvolutionResult;
import org.jenetics.util.Factory;
public class SimpleGeneticAlgorithm {
private static Integer eval(Genotype<BitGene> gt) {
return gt.getChromosome()
.as(BitChromosome.class)
.bitCount();
}
public static void main(String[] args) {
Factory<Genotype<BitGene>> gtf = Genotype.of(BitChromosome.of(10, 0.5));
System.out.println("Before the evolution:\n" + gtf);
Engine<BitGene, Integer> engine = Engine.builder(SimpleGeneticAlgorithm::eval, gtf)
.build();
Genotype<BitGene> result = engine.stream()
.limit(500)
.collect(EvolutionResult.toBestGenotype());
System.out.println("After the evolution:\n" + result);
}
}

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/SpringsteenProblem.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import static java.util.Objects.requireNonNull;
import java.util.function.Function;
import java.util.stream.Collectors;
import org.jenetics.BitGene;
import org.jenetics.engine.Codec;
import org.jenetics.engine.Engine;
import org.jenetics.engine.EvolutionResult;
import org.jenetics.engine.Problem;
import org.jenetics.engine.codecs;
import org.jenetics.util.ISeq;
public class SpringsteenProblem implements Problem<ISeq<SpringsteenRecord>, BitGene, Double> {
private ISeq<SpringsteenRecord> records;
private double maxPricePerUniqueSong;
public SpringsteenProblem(ISeq<SpringsteenRecord> records, double maxPricePerUniqueSong) {
this.records = requireNonNull(records);
this.maxPricePerUniqueSong = maxPricePerUniqueSong;
}
@Override
public Function<ISeq<SpringsteenRecord>, Double> fitness() {
return SpringsteenRecords -> {
double cost = SpringsteenRecords.stream()
.mapToDouble(r -> r.price)
.sum();
int uniqueSongCount = SpringsteenRecords.stream()
.flatMap(r -> r.songs.stream())
.collect(Collectors.toSet())
.size();
double pricePerUniqueSong = cost / uniqueSongCount;
return pricePerUniqueSong <= maxPricePerUniqueSong ? uniqueSongCount : 0.0;
};
}
@Override
public Codec<ISeq<SpringsteenRecord>, BitGene> codec() {
return codecs.ofSubSet(records);
}
public static void main(String[] args) {
double maxPricePerUniqueSong = 2.5;
SpringsteenProblem springsteen = new SpringsteenProblem(
ISeq.of(new SpringsteenRecord("SpringsteenRecord1", 25, ISeq.of("Song1", "Song2", "Song3", "Song4", "Song5", "Song6")), new SpringsteenRecord("SpringsteenRecord2", 15, ISeq.of("Song2", "Song3", "Song4", "Song5", "Song6", "Song7")),
new SpringsteenRecord("SpringsteenRecord3", 35, ISeq.of("Song5", "Song6", "Song7", "Song8", "Song9", "Song10")), new SpringsteenRecord("SpringsteenRecord4", 17, ISeq.of("Song9", "Song10", "Song12", "Song4", "Song13", "Song14")),
new SpringsteenRecord("SpringsteenRecord5", 29, ISeq.of("Song1", "Song2", "Song13", "Song14", "Song15", "Song16")), new SpringsteenRecord("SpringsteenRecord6", 5, ISeq.of("Song18", "Song20", "Song30", "Song40"))),
maxPricePerUniqueSong);
Engine<BitGene, Double> engine = Engine.builder(springsteen)
.build();
ISeq<SpringsteenRecord> result = springsteen.codec()
.decoder()
.apply(engine.stream()
.limit(10)
.collect(EvolutionResult.toBestGenotype()));
double cost = result.stream()
.mapToDouble(r -> r.price)
.sum();
int uniqueSongCount = result.stream()
.flatMap(r -> r.songs.stream())
.collect(Collectors.toSet())
.size();
double pricePerUniqueSong = cost / uniqueSongCount;
System.out.println("Overall cost: " + cost);
System.out.println("Unique songs: " + uniqueSongCount);
System.out.println("Cost per song: " + pricePerUniqueSong);
System.out.println("Records: " + result.map(r -> r.name)
.toString(", "));
}
}

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/SpringsteenRecord.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import static java.util.Objects.requireNonNull;
import org.jenetics.util.ISeq;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@NoArgsConstructor
public class SpringsteenRecord {
String name;
double price;
ISeq<String> songs;
public SpringsteenRecord(String name, double price, ISeq<String> songs) {
this.name = requireNonNull(name);
this.price = price;
this.songs = requireNonNull(songs);
}
}

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/SubsetSum.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import static java.util.Objects.requireNonNull;
import java.util.Random;
import java.util.function.Function;
import org.jenetics.EnumGene;
import org.jenetics.Mutator;
import org.jenetics.PartiallyMatchedCrossover;
import org.jenetics.Phenotype;
import org.jenetics.engine.Codec;
import org.jenetics.engine.Engine;
import org.jenetics.engine.EvolutionResult;
import org.jenetics.engine.Problem;
import org.jenetics.engine.codecs;
import org.jenetics.engine.limit;
import org.jenetics.util.ISeq;
import org.jenetics.util.LCG64ShiftRandom;
public class SubsetSum implements Problem<ISeq<Integer>, EnumGene<Integer>, Integer> {
private ISeq<Integer> basicSet;
private int size;
public SubsetSum(ISeq<Integer> basicSet, int size) {
this.basicSet = requireNonNull(basicSet);
this.size = size;
}
@Override
public Function<ISeq<Integer>, Integer> fitness() {
return subset -> Math.abs(subset.stream()
.mapToInt(Integer::intValue)
.sum());
}
@Override
public Codec<ISeq<Integer>, EnumGene<Integer>> codec() {
return codecs.ofSubSet(basicSet, size);
}
public static SubsetSum of(int n, int k, Random random) {
return new SubsetSum(random.doubles()
.limit(n)
.mapToObj(d -> (int) ((d - 0.5) * n))
.collect(ISeq.toISeq()), k);
}
public static void main(String[] args) {
SubsetSum problem = of(500, 15, new LCG64ShiftRandom(101010));
Engine<EnumGene<Integer>, Integer> engine = Engine.builder(problem)
.minimizing()
.maximalPhenotypeAge(5)
.alterers(new PartiallyMatchedCrossover<>(0.4), new Mutator<>(0.3))
.build();
Phenotype<EnumGene<Integer>, Integer> result = engine.stream()
.limit(limit.bySteadyFitness(55))
.collect(EvolutionResult.toBestPhenotype());
System.out.print(result);
}
}

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algorithms/src/main/java/com/baeldung/algorithms/ga/jenetics/TravelingSalesman.java Normal file
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package com.baeldung.algorithms.ga.jenetics;
import static java.lang.Math.PI;
import static java.lang.Math.abs;
import static java.lang.Math.sin;
import static org.jenetics.engine.EvolutionResult.toBestPhenotype;
import static org.jenetics.engine.limit.bySteadyFitness;
import java.util.stream.IntStream;
import org.jenetics.EnumGene;
import org.jenetics.Optimize;
import org.jenetics.PartiallyMatchedCrossover;
import org.jenetics.Phenotype;
import org.jenetics.SwapMutator;
import org.jenetics.engine.Engine;
import org.jenetics.engine.EvolutionStatistics;
import org.jenetics.engine.codecs;
public class TravelingSalesman {
private static final int STOPS = 50;
private static final double[][] ADJACENCE = matrix(STOPS);
private static double[][] matrix(int stops) {
final double radius = 100.0;
double[][] matrix = new double[stops][stops];
for (int i = 0; i < stops; ++i) {
for (int j = 0; j < stops; ++j) {
matrix[i][j] = chord(stops, abs(i - j), radius);
}
}
return matrix;
}
private static double chord(int stops, int i, double r) {
return 2.0 * r * abs(sin(PI * i / stops));
}
private static double dist(final int[] path) {
return IntStream.range(0, STOPS)
.mapToDouble(i -> ADJACENCE[path[i]][path[(i + 1) % STOPS]])
.sum();
}
public static void main(String[] args) {
final Engine<EnumGene<Integer>, Double> engine = Engine.builder(TravelingSalesman::dist, codecs.ofPermutation(STOPS))
.optimize(Optimize.MINIMUM)
.maximalPhenotypeAge(11)
.populationSize(500)
.alterers(new SwapMutator<>(0.2), new PartiallyMatchedCrossover<>(0.35))
.build();
final EvolutionStatistics<Double, ?> statistics = EvolutionStatistics.ofNumber();
final Phenotype<EnumGene<Integer>, Double> best = engine.stream()
.limit(bySteadyFitness(15))
.limit(250)
.peek(statistics)
.collect(toBestPhenotype());
System.out.println(statistics);
System.out.println(best);
}
}