Module io.jenetics.base
Package io.jenetics.engine

Class EvolutionResult<G extends Gene<?,G>,C extends Comparable<? super C>>

java.lang.Object
io.jenetics.engine.EvolutionResult<G,C>
Type Parameters:
G - the gene type
C - the fitness type
All Implemented Interfaces:
Serializable, Comparable<EvolutionResult<G,C>>
public final class EvolutionResult<G extends Gene<?,G>,C extends Comparable<? super C>> extends Object implements Comparable<EvolutionResult<G,C>>, Serializable
Represents a state of the GA after an evolution step. It also represents the final state of an evolution process and can be created with an appropriate collector: 
final Problem<ISeq<Point>, EnumGene<Point>, Double> tsm = ...;
final EvolutionResult<EnumGene<Point>, Double> result = Engine.builder(tsm)
    .optimize(Optimize.MINIMUM)
    .build()
    .stream()
    .limit(100)
    .collect(EvolutionResult.toBestEvolutionResult());
Since:
3.0
Version:
6.0
See Also:
Implementation Requirements:
This class implements the Comparable interface, which compares two EvolutionResult objects according its optimal fitness value. This means that the better evolution result is always greater, no matter if the fitness function is minimized or maximized. 
final EvolutionResult<DoubleGene, Double> result1 = ...;
final EvolutionResult<DoubleGene, Double> result2 = ...;

if (result1.compareTo(result2) > 0) {
     // Holds for maximizing evolution results.
    assert result1.bestFitness() > result2.bestFitness();

    // Holds for minimizing evolution results.
   assert result1.bestFitness() < result2.bestFitness();
}
Implementation Note:
This class is immutable and thread-safe.

  • Method Details

    • optimize

      public Optimize optimize()
      Return the optimization strategy used.
      Returns:
      the optimization strategy used

    • population

      public ISeq<Phenotype<G,C>> population()
      Return the population after the evolution step.
      Returns:
      the population after the evolution step

    • genotypes

      public ISeq<Genotype<G>> genotypes()
      Return the current list of genotypes of this evolution result.
      Returns:
      the list of genotypes of this evolution result.
      Since:
      5.2

    • generation

      public long generation()
      The current generation.
      Returns:
      the current generation

    • totalGenerations

      public long totalGenerations()
      Return the generation count evaluated so far.
      Returns:
      the total number of generations evaluated so far

    • durations

      public EvolutionDurations durations()
      Return the timing (meta) information of the evolution step.
      Returns:
      the timing (meta) information of the evolution step

    • killCount

      public int killCount()
      Return the number of killed individuals.
      Returns:
      the number of killed individuals

    • invalidCount

      public int invalidCount()
      Return the number of invalid individuals.
      Returns:
      the number of invalid individuals

    • alterCount

      public int alterCount()
      The number of altered individuals.
      Returns:
      the number of altered individuals

    • bestPhenotype

      public Phenotype<G,C> bestPhenotype()
      Return the best Phenotype of the result population.
      Returns:
      the best Phenotype of the result population

    • worstPhenotype

      public Phenotype<G,C> worstPhenotype()
      Return the worst Phenotype of the result population.
      Returns:
      the worst Phenotype of the result population

    • bestFitness

      public C bestFitness()
      Return the best population fitness.
      Returns:
      The best population fitness.

    • worstFitness

      public C worstFitness()
      Return the worst population fitness.
      Returns:
      The worst population fitness.

    • next

      public EvolutionStart<G,C> next()
      Return the next evolution start object with the current population and the incremented generation.
      Returns:
      the next evolution start object
      Since:
      4.1

    • toEvolutionStart

      public EvolutionStart<G,C> toEvolutionStart()
      Return the current evolution result object as an EvolutionStart object with the current population and current total generation.
      Returns:
      the current result as evolution start
      Since:
      4.1

    • compareTo

      public int compareTo(EvolutionResult<G,C> other)
      Compare this evolution result with another one, according the population's best individual.
      Specified by:
      compareTo in interface Comparable<G extends Gene<?,G>>
      Parameters:
      other - the other evolution result to compare
      Returns:
      a negative integer, zero, or a positive integer as this result is less than, equal to, or greater than the specified result.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • equals

      public boolean equals(Object obj)
      Overrides:
      equals in class Object

    • toBestEvolutionResult

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> Collector<EvolutionResult<G,C>,?,EvolutionResult<G,C>> toBestEvolutionResult()
      Return a collector which collects the best result of an evolution stream. 
      final Problem<ISeq<Point>, EnumGene<Point>, Double> tsm = ...;
final EvolutionResult<EnumGene<Point>, Double> result = Engine.builder(tsm)
    .optimize(Optimize.MINIMUM).build()
    .stream()
    .limit(100)
    .collect(EvolutionResult.toBestEvolutionResult());
      If the collected EvolutionStream is empty, the collector returns null.
      Type Parameters:
      G - the gene type
      C - the fitness type
      Returns:
      a collector which collects the best result of an evolution stream

    • toBestPhenotype

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> Collector<EvolutionResult<G,C>,?,Phenotype<G,C>> toBestPhenotype()
      Return a collector which collects the best phenotype of an evolution stream. 
      final Problem<ISeq<Point>, EnumGene<Point>, Double> tsm = ...;
final Phenotype<EnumGene<Point>, Double> result = Engine.builder(tsm)
    .optimize(Optimize.MINIMUM).build()
    .stream()
    .limit(100)
    .collect(EvolutionResult.toBestPhenotype());
      If the collected EvolutionStream is empty, the collector returns null.
      Type Parameters:
      G - the gene type
      C - the fitness type
      Returns:
      a collector which collects the best phenotype of an evolution stream

    • toBestGenotype

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> Collector<EvolutionResult<G,C>,?,Genotype<G>> toBestGenotype()
      Return a collector which collects the best genotype of an evolution stream. 
      final Problem<ISeq<Point>, EnumGene<Point>, Double> tsm = ...;
final Genotype<EnumGene<Point>> result = Engine.builder(tsm)
    .optimize(Optimize.MINIMUM).build()
    .stream()
    .limit(100)
    .collect(EvolutionResult.toBestGenotype());
      If the collected EvolutionStream is empty, the collector returns null.
      Type Parameters:
      G - the gene type
      C - the fitness type
      Returns:
      a collector which collects the best genotype of an evolution stream

    • toBestResult

      public static <G extends Gene<?, G>, C extends Comparable<? super C>, T> Collector<EvolutionResult<G,C>,?,T> toBestResult(Function<Genotype<G>,T> decoder)
      Return a collector which collects the best result (in the native problem space). 
      final Problem<ISeq<Point>, EnumGene<Point>, Double> tsm = ...;
final ISeq<Point> route = Engine.builder(tsm)
    .optimize(Optimize.MINIMUM).build()
    .stream()
    .limit(100)
    .collect(EvolutionResult.toBestResult(tsm.codec().decoder()));
      If the collected EvolutionStream is empty, the collector returns null.
      Type Parameters:
      G - the gene type
      C - the fitness result type
      T - the native problem result type
      Parameters:
      decoder - the decoder which converts the Genotype into the result of the problem space.
      Returns:
      a collector which collects the best result of an evolution stream
      Throws:
      NullPointerException - if the given decoder is null
      Since:
      3.6

    • toBestResult

      public static <G extends Gene<?, G>, C extends Comparable<? super C>, T> Collector<EvolutionResult<G,C>,?,T> toBestResult(Codec<T,G> codec)
      Return a collector which collects the best result (in the native problem space). 
      final Problem<ISeq<Point>, EnumGene<Point>, Double> tsm = ...;
final ISeq<Point> route = Engine.builder(tsm)
    .optimize(Optimize.MINIMUM).build()
    .stream()
    .limit(100)
    .collect(EvolutionResult.toBestResult(tsm.codec()));
      If the collected EvolutionStream is empty, the collector returns null.
      Type Parameters:
      G - the gene type
      C - the fitness result type
      T - the native problem result type
      Parameters:
      codec - the problem decoder
      Returns:
      a collector which collects the best result of an evolution stream
      Throws:
      NullPointerException - if the given codec is null
      Since:
      3.6

    • toUniquePopulation

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> EvolutionInterceptor<G,C> toUniquePopulation(Factory<Genotype<G>> factory, int maxRetries)
      Return a mapping function, which removes duplicate individuals from the population and replaces it with newly created one by the given genotype factory. 
      final Problem<Double, DoubleGene, Integer> problem = ...;
final Engine<DoubleGene, Integer> engine = Engine.builder(problem)
    .interceptor(toUniquePopulation(problem.codec().encoding(), 100))
    .build();
final Genotype<DoubleGene> best = engine.stream()
    .limit(100)
    .collect(EvolutionResult.toBestGenotype());
      Type Parameters:
      G - the gene type
      C - the fitness function result type
      Parameters:
      factory - the genotype factory which creates new individuals
      maxRetries - the maximal number of genotype creations tries
      Returns:
      a mapping function, which removes duplicate individuals from the population
      Throws:
      NullPointerException - if the given genotype factory is null
      Since:
      6.0
      See Also:

    • toUniquePopulation

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> EvolutionInterceptor<G,C> toUniquePopulation(Factory<Genotype<G>> factory)
      Return a mapping function, which removes duplicate individuals from the population and replaces it with newly created one by the given genotype factory. 
      final Problem<Double, DoubleGene, Integer> problem = ...;
final Engine<DoubleGene, Integer> engine = Engine.builder(problem)
    .interceptor(toUniquePopulation(problem.codec().encoding()))
    .build();
final Genotype<DoubleGene> best = engine.stream()
    .limit(100)
    .collect(EvolutionResult.toBestGenotype());
      Type Parameters:
      G - the gene type
      C - the fitness function result type
      Parameters:
      factory - the genotype factory which creates new individuals
      Returns:
      a mapping function, which removes duplicate individuals from the population
      Throws:
      NullPointerException - if the given genotype factory is null
      Since:
      6.0
      See Also:

    • toUniquePopulation

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> EvolutionInterceptor<G,C> toUniquePopulation(int maxRetries)
      Return a mapping function, which removes duplicate individuals from the population and replaces it with newly created one by the existing genotype factory. 
      final Problem<Double, DoubleGene, Integer> problem = ...;
final Engine<DoubleGene, Integer> engine = Engine.builder(problem)
    .interceptor(toUniquePopulation(10))
    .build();
final Genotype<DoubleGene> best = engine.stream()
    .limit(100)
    .collect(EvolutionResult.toBestGenotype(5));
      Type Parameters:
      G - the gene type
      C - the fitness function result type
      Parameters:
      maxRetries - the maximal number of genotype creations tries
      Returns:
      a mapping function, which removes duplicate individuals from the population
      Throws:
      NullPointerException - if the given genotype factory is null
      Since:
      6.0
      See Also:

    • toUniquePopulation

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> EvolutionInterceptor<G,C> toUniquePopulation()
      Return a mapping function, which removes duplicate individuals from the population and replaces it with newly created one by the existing genotype factory. 
      final Problem<Double, DoubleGene, Integer> problem = ...;
final Engine<DoubleGene, Integer> engine = Engine.builder(problem)
    .interceptor(EvolutionResult.toUniquePopulation())
    .build();
final Genotype<DoubleGene> best = engine.stream()
    .limit(100)
    .collect(EvolutionResult.toBestGenotype());
      Type Parameters:
      G - the gene type
      C - the fitness function result type
      Returns:
      a mapping function, which removes duplicate individuals from the population
      Throws:
      NullPointerException - if the given genotype factory is null
      Since:
      6.0
      See Also:

    • of

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> EvolutionResult<G,C> of(Optimize optimize, ISeq<Phenotype<G,C>> population, long generation, long totalGenerations, EvolutionDurations durations, int killCount, int invalidCount, int alterCount)
      Return a new EvolutionResult object with the given values.
      Type Parameters:
      G - the gene type
      C - the fitness type
      Parameters:
      optimize - the optimization strategy used
      population - the population after the evolution step
      generation - the current generation
      totalGenerations - the overall number of generations
      durations - the timing (meta) information
      killCount - the number of individuals which has been killed
      invalidCount - the number of individuals which has been removed as invalid
      alterCount - the number of individuals which has been altered
      Returns:
      an new evolution result object
      Throws:
      NullPointerException - if one of the parameters is null

    • of

      public static <G extends Gene<?, G>, C extends Comparable<? super C>> EvolutionResult<G,C> of(Optimize optimize, ISeq<Phenotype<G,C>> population, long generation, EvolutionDurations durations, int killCount, int invalidCount, int alterCount)
      Return a new EvolutionResult object with the given values.
      Type Parameters:
      G - the gene type
      C - the fitness type
      Parameters:
      optimize - the optimization strategy used
      population - the population after the evolution step
      generation - the current generation
      durations - the timing (meta) information
      killCount - the number of individuals which has been killed
      invalidCount - the number of individuals which has been removed as invalid
      alterCount - the number of individuals which has been altered
      Returns:
      an new evolution result object
      Throws:
      NullPointerException - if one of the parameters is null