Documentation of 'ec.BreedingSource' Java class
BreedingSource
Skip navigation links
ec

Class BreedingSource

  • All Implemented Interfaces:
    Prototype, Setup, RandomChoiceChooserD, java.io.Serializable, java.lang.Cloneable
    Direct Known Subclasses:
    BreedingPipeline, SelectionMethod

    public abstract class BreedingSource
extends java.lang.Object
implements Prototype, RandomChoiceChooserD
    A BreedingSource is a Prototype which provides Individuals to populate new populations based on old ones. The BreedingSource/BreedingPipeline/SelectionMethod mechanism is inherently designed to work within single subpopulations, which is by far the most common case. If for some reason you need to breed among different subpopulations to produce new ones in a manner that can't be handled with exchanges, you will probably have to write your own custom Breeder; you'd have to write your own custom breeding pipelines anyway of course, though you can probably get away with reusing the SelectionMethods.

    A BreedingSource may have parent sources which feed it as well. Some BreedingSources, SelectionMethods, are meant solely to plug into other BreedingSources, BreedingPipelines. BreedingPipelines can plug into other BreedingPipelines, and can also be used to provide the final Individual meant to populate a new generation.

    Think of BreedingSources as Streams of Individuals; at one end of the stream is the provider, a SelectionMethod, which picks individuals from the old population. At the other end of the stream is a BreedingPipeline which hands you the finished product, a small set of new Individuals for you to use in populating your new population.

    Parameters

    base.prob
    0.0 <= double <= 1.0, or undefined    		 (probability this BreedingSource gets chosen. Undefined is only valid if the caller of this BreedingSource doesn't need a probability)
    See Also:
    Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field and Description
      static double NO_PROBABILITY 
      static java.lang.String P_PROB 
      double probability
      The probability that this BreedingSource will be chosen to breed over other BreedingSources.

    • Constructor Summary

      Constructors 
      Constructor and Description
      BreedingSource() 

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method and Description
      java.lang.Object clone()
      Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.
      abstract void finishProducing(EvolutionState s, int subpopulation, int thread)
      Called after produce(...), usually once a generation, or maybe only once if you're doing steady-state evolution (at the end of the run).
      double getProbability(java.lang.Object obj)
      Returns obj's probability
      static int pickRandom(BreedingSource[] sources, double prob)
      Picks a random source from an array of sources, with their probabilities normalized and summed as follows: For example, if four breeding source probabilities are {0.3, 0.2, 0.1, 0.4}, then they should get normalized and summed by the outside owners as: {0.3, 0.5, 0.6, 1.0}.
      void preparePipeline(java.lang.Object hook)
      A hook which should be passed to all your subsidiary breeding sources.
      abstract void prepareToProduce(EvolutionState state, int subpopulation, int thread)
      Called before produce(...), usually once a generation, or maybe only once if you're doing steady-state evolution, to let the breeding source "warm up" prior to producing.
      abstract int produce(int min, int max, int start, int subpopulation, Individual[] inds, EvolutionState state, int thread)
      Produces n individuals from the given subpopulation and puts them into inds[start...start+n-1], where n = Min(Max(q,min),max), where q is the "typical" number of individuals the BreedingSource produces in one shot, and returns n.
      abstract boolean produces(EvolutionState state, Population newpop, int subpopulation, int thread)
      Returns true if this BreedingSource, when attached to the given subpopulation, will produce individuals of the subpopulation's species.
      void setProbability(java.lang.Object obj, double prob)
      Sets obj's probability
      void setup(EvolutionState state, Parameter base)
      Sets up the BreedingPipeline.
      static void setupProbabilities(BreedingSource[] sources)
      Normalizes and arranges the probabilities in sources so that they are usable by pickRandom(...).
      abstract int typicalIndsProduced()
      Returns the "typical" number of individuals generated with one call of produce(...).

      • Methods inherited from class java.lang.Object

        equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • probability

        public double probability
        The probability that this BreedingSource will be chosen to breed over other BreedingSources. This may or may not be used, depending on what the caller to this BreedingSource is. It also might be modified by external sources owning this object, for their own purposes. A BreedingSource should not use it for any purpose of its own, nor modify it except when setting it up.

        The most common modification is to normalize it with some other set of probabilities, then set all of them up in increasing summation; this allows the use of the fast static BreedingSource-picking utility method, BreedingSource.pickRandom(...). In order to use this method, for example, if four breeding source probabilities are {0.3, 0.2, 0.1, 0.4}, then they should get normalized and summed by the outside owners as: {0.3, 0.5, 0.6, 1.0}.

    • Constructor Detail

      • BreedingSource

        public BreedingSource()

    • Method Detail

      • setup

        public void setup(EvolutionState state,
                  Parameter base)
        Sets up the BreedingPipeline. You can use state.output.error here because the top-level caller promises to call exitIfErrors() after calling setup. Note that probability might get modified again by an external source if it doesn't normalize right.

        The most common modification is to normalize it with some other set of probabilities, then set all of them up in increasing summation; this allows the use of the fast static BreedingSource-picking utility method, BreedingSource.pickRandom(...). In order to use this method, for example, if four breeding source probabilities are {0.3, 0.2, 0.1, 0.4}, then they should get normalized and summed by the outside owners as: {0.3, 0.5, 0.6, 1.0}.

        Specified by:
        setup in interface Prototype
        Specified by:
        setup in interface Setup
        See Also:
        Prototype.setup(EvolutionState,Parameter)

      • pickRandom

        public static int pickRandom(BreedingSource[] sources,
                             double prob)
        Picks a random source from an array of sources, with their probabilities normalized and summed as follows: For example, if four breeding source probabilities are {0.3, 0.2, 0.1, 0.4}, then they should get normalized and summed by the outside owners as: {0.3, 0.5, 0.6, 1.0}.

      • setupProbabilities

        public static void setupProbabilities(BreedingSource[] sources)
        Normalizes and arranges the probabilities in sources so that they are usable by pickRandom(...). If the sources have all zero probabilities, then a uniform selection is used. Negative probabilities will generate an ArithmeticException, as will an empty source array.

      • typicalIndsProduced

        public abstract int typicalIndsProduced()
        Returns the "typical" number of individuals generated with one call of produce(...).

      • produces

        public abstract boolean produces(EvolutionState state,
                                 Population newpop,
                                 int subpopulation,
                                 int thread)
        Returns true if this BreedingSource, when attached to the given subpopulation, will produce individuals of the subpopulation's species. SelectionMethods should additionally make sure that their Fitnesses are of a valid type, if necessary. newpop *may* be the same as state.population

      • prepareToProduce

        public abstract void prepareToProduce(EvolutionState state,
                                      int subpopulation,
                                      int thread)
        Called before produce(...), usually once a generation, or maybe only once if you're doing steady-state evolution, to let the breeding source "warm up" prior to producing. Individuals should be produced from old individuals in positions [start...start+length] in the subpopulation only. May be called again to reset the BreedingSource for a whole 'nuther subpopulation.

      • finishProducing

        public abstract void finishProducing(EvolutionState s,
                                     int subpopulation,
                                     int thread)
        Called after produce(...), usually once a generation, or maybe only once if you're doing steady-state evolution (at the end of the run).

      • produce

        public abstract int produce(int min,
                            int max,
                            int start,
                            int subpopulation,
                            Individual[] inds,
                            EvolutionState state,
                            int thread)
        Produces n individuals from the given subpopulation and puts them into inds[start...start+n-1], where n = Min(Max(q,min),max), where q is the "typical" number of individuals the BreedingSource produces in one shot, and returns n. max must be >= min, and min must be >= 1. For example, crossover might typically produce two individuals, tournament selection might typically produce a single individual, etc.

      • clone

        public java.lang.Object clone()
        Description copied from interface: Prototype
        Creates a new individual cloned from a prototype, and suitable to begin use in its own evolutionary context.

        Typically this should be a full "deep" clone. However, you may share certain elements with other objects rather than clone hem, depending on the situation:

        • If you hold objects which are shared with other instances, don't clone them.
        • If you hold objects which must be unique, clone them.
        • If you hold objects which were given to you as a gesture of kindness, and aren't owned by you, you probably shouldn't clone them.
        • DON'T attempt to clone: Singletons, Cliques, or Groups.
        • Arrays are not cloned automatically; you may need to clone an array if you're not sharing it with other instances. Arrays have the nice feature of being copyable by calling clone() on them.

        Implementations.

        • If no ancestor of yours implements clone(), and you have no need to do clone deeply, and you are abstract, then you should not declare clone().
        • If no ancestor of yours implements clone(), and you have no need to do clone deeply, and you are not abstract, then you should implement it as follows: 

           public Object clone() 
     {
     try
         { 
         return super.clone();
         }
     catch ((CloneNotSupportedException e)
         { throw new InternalError(); } // never happens
     }
        • If no ancestor of yours implements clone(), but you need to deep-clone some things, then you should implement it as follows: 

           public Object clone() 
     {
     try
         { 
         MyObject myobj = (MyObject) (super.clone());

         // put your deep-cloning code here...
         }
     catch ((CloneNotSupportedException e)
         { throw new InternalError(); } // never happens
     return myobj;
     }
        • If an ancestor has implemented clone(), and you also need to deep clone some things, then you should implement it as follows: 

           public Object clone() 
     { 
     MyObject myobj = (MyObject) (super.clone());

     // put your deep-cloning code here...

     return myobj;
     }
        Specified by:
        clone in interface Prototype
        Overrides:
        clone in class java.lang.Object

      • preparePipeline

        public void preparePipeline(java.lang.Object hook)
        A hook which should be passed to all your subsidiary breeding sources. The default does this for you already, so ordinarily you don't need to change anything. If you are a BreedingPipeline and you implement your sources in a way different than using the sources[] array, be sure to override this method so that it calls preparePipeline(hook) on all of your sources.

        ECJ at present does not custom-implement or call this method: it's available for you. Becuase it has custom functionality, this method might get called more than once, and by various objects as needed. If you use it, you should determine somehow how to use it to send information under the assumption that it might be sent by nested items in the pipeline; you don't want to scribble over each other's calls! Note that this method should travel *all* breeding source paths regardless of whether or not it's redundant to do so.

Skip navigation links

DMelt 3.0 © DataMelt by jWork.ORG

You see the box below because you did not login.