Package ec.vector

Class FloatVectorSpecies

All Implemented Interfaces:
Prototype, Setup, Serializable, Cloneable
Direct Known Subclasses:
AMALGAMSpecies, CMAESSpecies

public class FloatVectorSpecies extends VectorSpecies
FloatVectorSpecies is a subclass of VectorSpecies with special constraints for floating-point vectors, namely FloatVectorIndividual and DoubleVectorIndividual.

FloatVectorSpecies can specify a number of parameters globally, per-segment, and per-gene. See VectorSpecies for information on how to this works.

FloatVectorSpecies defines a minimum and maximum gene value. These values are used during initialization and, depending on whether mutation-bounded is true, also during various mutation algorithms to guarantee that the gene value will not exceed these minimum and maximum bounds.

FloatVectorSpecies provides support for five ways of mutating a gene.

  • reset Replacing the gene's value with a value uniformly drawn from the gene's range (the default behavior).
  • gaussPerturbing the gene's value with gaussian noise; if the gene-by-gene range is used, than the standard deviation is scaled to reflect each gene's range. If the gaussian mutation's standard deviation is too large for the range, than there's a large probability the mutated value will land outside range. We will try again a number of times (100) before giving up and using the previous mutation method.
  • polynomial Perturbing the gene's value with noise chosen from a polynomial distribution, similar to the gaussian distribution. The polynomial distribution was popularized by Kalyanmoy Deb and is found in many of his publications (see http://www.iitk.ac.in/kangal/deb.shtml). The polynomial distribution has two options. First, there is the index. This variable defines the shape of the distribution and is in some sense the equivalent of the standard deviation in the gaussian distribution. The index is an integer. If it is zero, the polynomial distribution is simply the uniform distribution from [1,-1]. If it is 1, the polynomial distribution is basically a triangular distribution from [1,-1] peaking at 0. If it is 2, the polynomial distribution follows a squared function, again peaking at 0. Larger values result in even more peaking and narrowness. The default values used in nearly all of the NSGA-II and Deb work is 20. Second, there is whether or not the value is intended for bounded genes. The default polynomial distribution is used when we assume the gene can take on literally any value, even beyond the min and max values. For genes which are restricted to be between min and max, there is an alternative version of the polynomial distribution, used by Deb's team but not discussed much in the literature, desiged for that situation. We assume boundedness by default, and have found it to be somewhat better for NSGA-II and SPEA2 problems. For a description of this alternative version, see "A Niched-Penalty Approach for Constraint Handling in Genetic Algorithms" by Kalyanmoy Deb and Samir Agrawal. Deb's default implementation bounds the result to min or max; instead ECJ's implementation of the polynomial distribution retries until it finds a legal value. This will be just fine for ranges like [0,1], but for smaller ranges you may be waiting a long time.
  • integer-reset Replacing the gene's value with a value uniformly drawn from the gene's range but restricted to only integers.
  • integer-random-walk Replacing the gene's value by performing a random walk starting at the gene value. The random walk either adds 1 or subtracts 1 (chosen at random), then does a coin-flip to see whether to continue the random walk. When the coin-flip finally comes up false, the gene value is set to the current random walk position.

FloatVectorSpecies provides support for two ways of initializing a gene. The initialization procedure is determined by the choice of mutation procedure as described above. If the mutation is floating-point (reset, gauss, polynomial), then initialization will be done by resetting the gene to uniformly chosen floating-point value between the minimum and maximum legal gene values, inclusive. If the mutation is integer (integer-reset, integer-random-walk), then initialization will be done by performing the same kind of reset, but restricting values to integers only.

Parameters

double (default=0.0)double >= base.min-gene
base.min-gene   or
base.segment.segment-number.min-gene   or
base.min-gene.gene-number
0.0 <= double <= 1.0
(probability that a gene will get mutated over default mutation)
(the minimum gene value)
 
base.max-gene   or
base.segment.segment-number.max-gene   or
base.max-gene.gene-number
0.0 <= double <= 1.0
(probability that a gene will get mutated over default mutation)
(the maximum gene value)
 
base.mutation-type   or
base.segment.segment-number.mutation-type   or
base.mutation-prob.gene-number
reset, gauss, polynomial, integer-reset, or integer-random-walk (default=reset)
(the mutation type)
 
base.mutation-stdev   or
base.segment.segment-number.mutation-stdev   or
base.mutation-stdev.gene-number
double ≥ 0
(the standard deviation or the gauss perturbation)
base.distribution-index   or
base.segment.segment-number.distribution-index   or
base.distribution-index.gene-number
int ≥ 0
(the mutation distribution index for the polynomial mutation distribution)
 
base.alternative-polynomial-version   or
base.segment.segment-number.alternative-polynomial-version   or
base.alternative-polynomial-version.gene-number
boolean (default=true)
(whether to use the "bounded" variation of the polynomial mutation or the standard ("unbounded") version)
 
base.random-walk-probability   or
base.segment.segment-number.random-walk-probability   or
base.random-walk-probability.gene-number
0.0 <= double <= 1.0
(the probability that a random walk will continue. Random walks go up or down by 1.0 until the coin flip comes up false.)
base.mutation-bounded   or
base.segment.segment-number.mutation-bounded   or
base.mutation-bounded.gene-number
boolean (default=true)
(whether mutation is restricted to only being within the min/max gene values. Does not apply to SimulatedBinaryCrossover (which is always bounded))
  base.out-of-bounds-retries
int ≥ 0 (default=100)
(number of times the gaussian mutation got the gene out of range before we give up and reset the gene's value; 0 means "never give up")
See Also:
  • Field Details

    • P_MINGENE

      public static final String P_MINGENE
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    • P_MAXGENE

      public static final String P_MAXGENE
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    • P_MUTATIONTYPE

      public static final String P_MUTATIONTYPE
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    • P_STDEV

      public static final String P_STDEV
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    • P_MUTATION_DISTRIBUTION_INDEX

      public static final String P_MUTATION_DISTRIBUTION_INDEX
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    • P_POLYNOMIAL_ALTERNATIVE

      public static final String P_POLYNOMIAL_ALTERNATIVE
      See Also:
    • V_RESET_MUTATION

      public static final String V_RESET_MUTATION
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    • V_GAUSS_MUTATION

      public static final String V_GAUSS_MUTATION
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    • V_POLYNOMIAL_MUTATION

      public static final String V_POLYNOMIAL_MUTATION
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    • V_INTEGER_RANDOM_WALK_MUTATION

      public static final String V_INTEGER_RANDOM_WALK_MUTATION
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    • V_INTEGER_RESET_MUTATION

      public static final String V_INTEGER_RESET_MUTATION
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    • P_RANDOM_WALK_PROBABILITY

      public static final String P_RANDOM_WALK_PROBABILITY
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    • P_OUTOFBOUNDS_RETRIES

      public static final String P_OUTOFBOUNDS_RETRIES
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    • P_MUTATION_BOUNDED

      public static final String P_MUTATION_BOUNDED
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    • C_RESET_MUTATION

      public static final int C_RESET_MUTATION
      See Also:
    • C_GAUSS_MUTATION

      public static final int C_GAUSS_MUTATION
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    • C_POLYNOMIAL_MUTATION

      public static final int C_POLYNOMIAL_MUTATION
      See Also:
    • C_INTEGER_RESET_MUTATION

      public static final int C_INTEGER_RESET_MUTATION
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    • C_INTEGER_RANDOM_WALK_MUTATION

      public static final int C_INTEGER_RANDOM_WALK_MUTATION
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    • minGene

      protected double[] minGene
      Min-gene value, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • maxGene

      protected double[] maxGene
      Max-gene value, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • mutationType

      protected int[] mutationType
      Mutation type, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • gaussMutationStdev

      protected double[] gaussMutationStdev
      Standard deviation for Gaussian Mutation, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • mutationIsBounded

      protected boolean[] mutationIsBounded
      Whether mutation is bounded to the min- and max-gene values, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • mutationDistributionIndex

      protected int[] mutationDistributionIndex
      The distribution index for Polynomial Mutation, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • polynomialIsAlternative

      protected boolean[] polynomialIsAlternative
      Whether the Polynomial Mutation method is the "alternative" method, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • randomWalkProbability

      protected double[] randomWalkProbability
      The continuation probability for Integer Random Walk Mutation, per gene. This array is one longer than the standard genome length. The top element in the array represents the parameters for genes in genomes which have extended beyond the genome length.
    • outOfBoundsRetries

      public int outOfBoundsRetries
      The number of times Polynomial Mutation or Gaussian Mutation retry for valid numbers until they get one.
    • DEFAULT_OUT_OF_BOUNDS_RETRIES

      public static final int DEFAULT_OUT_OF_BOUNDS_RETRIES
      See Also:
  • Constructor Details

    • FloatVectorSpecies

      public FloatVectorSpecies()
  • Method Details

    • outOfRangeRetryLimitReached

      public void outOfRangeRetryLimitReached(EvolutionState state)
    • maxGene

      public double maxGene(int gene)
    • minGene

      public double minGene(int gene)
    • mutationType

      public int mutationType(int gene)
    • gaussMutationStdev

      public double gaussMutationStdev(int gene)
    • mutationIsBounded

      public boolean mutationIsBounded(int gene)
    • mutationDistributionIndex

      public int mutationDistributionIndex(int gene)
    • polynomialIsAlternative

      public boolean polynomialIsAlternative(int gene)
    • randomWalkProbability

      public double randomWalkProbability(int gene)
    • inNumericalTypeRange

      public boolean inNumericalTypeRange(double geneVal)
    • setup

      public void setup(EvolutionState state, Parameter base)
      Description copied from class: Species
      The default version of setup(...) loads requested pipelines and calls setup(...) on them and normalizes their probabilities. If your individual prototype might need to know special things about the species (like parameters stored in it), then when you override this setup method, you'll need to set those parameters BEFORE you call super.setup(...), because the setup(...) code in Species sets up the prototype.
      Specified by:
      setup in interface Prototype
      Specified by:
      setup in interface Setup
      Overrides:
      setup in class VectorSpecies
      See Also:
    • loadParametersForGene

      protected void loadParametersForGene(EvolutionState state, int index, Parameter base, Parameter def, String postfix)
      Description copied from class: VectorSpecies
      Called when VectorSpecies is setting up per-gene and per-segment parameters. The index is the current gene whose parameter is getting set up. The Parameters in question are the bases for the gene. The postfix should be appended to the end of any parameter looked up (it often contains a number indicating the gene in question), such as state.parameters.exists(base.push(P_PARAM).push(postfix), def.push(P_PARAM).push(postfix)

      If you override this method, be sure to call super(...) at some point, ideally first.

      Overrides:
      loadParametersForGene in class VectorSpecies