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simplepopulation.h

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#include <population.h>

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// (              --  |  ___  |   )       --        |  ___   |           _   //
//  ---  | |/|/| |  ) | /   ) |---   __  |  ) |   | |  ___| -+- |  __  |/ \  //
//     ) | | | | |--  | |---  |     /  \ |--  |   | | (   |  |  | /  \ |   | //
// ___/  | | | | |    |  \__  |     \__/ |     \__! |  \__|   \ | \__/ |   | //
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class SimplePopulation : public Population {
    // The current set of individuals in the population
    Array<Individual>*      population;

    // Some statistics of the current population
    FitnessStats            mFitnessStats;

    // Number of elites, individuals who will survive intact to the
    // next generation
    int                     mElites;
    bool                    mUseGlobalElites;

    SelectionPrms           mSelectionParams;
    
    // Global micro portion The number of potential parents. The
    // semantics are dependent on the evolutionary strategy used
    bool                    mUseGlobalMicro;

    // Global q parameter for tournament selection
    bool                    mUseGlobalQ;

    // Global etaPlus parameter for linear ranking selection
    bool                    mUseGlobalEtaPlus;
    
    // Global mutation rate in the population. This is coefficient for
    // the mutation rate of each individual gene and defaults to 1.0
    MutationRate            mGlobalMutationRate;

    // Should the global mutation rate be adjusted automatically?
    bool                    autoadj_gmr;

  public:

    // Minimum allowed similarity between genomes
    double                  minsimilarity;
    
    // Constructs a binary population of the given size
                            SimplePopulation        (EAEnvironment& envr,
                                             const StringMap& params);

                            ~SimplePopulation       ();
    
    double                  evolve          (int generations, const char* savefile=NULL,
                                         double trg_fitn=-1);

    // Returns an individual in the population by it's index number
    const Individual&       operator[]		(int i) const {return (*population)[i];}

    // Same non-const
    Individual&             operator[]		(int i) {return (*population)[i];}
    
    // Returns the number of individuals in the population
    int                     size            () const {return population->size;}

    // Dumps the population to given output
    void                    print           (DataOStream& out) const;

    // Writes an one-line generation report to the given stream
    void                    report          (OStream& log) const;

    // Returns the current strategy
    const EAStrategy&       getstrategy     () const {return *strategy;}

    // Returns the number of times the population has been evaluated
    // (i.e., the generation)
    int                     getAge          () const {return mAge;}

    // Set the global mutation rate
    MutationRate&           mutRate         () {return mGlobalMutationRate;}

    SelectionPrms&          selParams       () {return mSelectionParams;}
    const SelectionPrms&    selParams       () const {return mSelectionParams;}

    // Resets the fitness averaging of individuals. Useful when
    // changing the objective function (old fitness values would be
    // invalid).
    void                    resetFitnesses  ();

    void                    check           () const;
    
  private:

    // Evaluates the population in an environment
    void                    evaluate        (EAEnvironment& envr, OStream& out);

    // Add population-dependent features to a genome. I suppose there
    // might be some use for this. Maybe.
    void                    addFeaturesTo   (Genome& genome) const;

    friend EAStrategy;
    /*
    friend CommonStrategy;
    friend CommaStrategy;
    friend PlusStrategy;
    */
    friend SelectionMatrix;
};

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