class BRKGA::Population

Overview

Encapsulates a population of chromosomes. More…

#include <brkga_mp_ipr.hpp>

class Population {
public:
    // fields

    std::vector<Chromosome> chromosomes;
    std::vector<std::pair<fitness_t, unsigned>> fitness;

    // construction

    Population(
        const unsigned chr_size,
        const unsigned pop_size
    );

    Population(const Population& other);

    // methods

    Population& operator = (const Population&);
    unsigned getChromosomeSize() const;
    unsigned getPopulationSize() const;

    double operator () (
        const unsigned chromosome,
        const unsigned allele
    ) const;

    double& operator () (
        const unsigned chromosome,
        const unsigned allele
    );

    Chromosome& operator () (unsigned chromosome);
    fitness_t getBestFitness() const;
    fitness_t getFitness(const unsigned i) const;
    Chromosome& getChromosome(unsigned i);
    const Chromosome& getChromosome(const unsigned i) const;
    void sortFitness(const Sense sense);

    void setFitness(
        const unsigned chromosome,
        const fitness_t value
    );
};

Detailed Documentation

Encapsulates a population of chromosomes.

Encapsulates a population of chromosomes providing supporting methods for making the implementation easier.

J All methods and attributes are public and can be manipulated directly from BRKGA algorithms. Note that this class is not meant to be used externally of this unit.

Fields

std::vector<Chromosome> chromosomes

Chromosomes as vectors of probabilities.

std::vector<std::pair<fitness_t, unsigned>> fitness

Fitness of each chromosome.

Construction

Population(
    const unsigned chr_size,
    const unsigned pop_size
)

Default constructor.

Parameters:

chr_size	size of chromosome.
pop_size	size of population.
std::range_error	if population size or chromosome size is zero.

Population(const Population& other)

Copy constructor.

Methods

Population& operator = (const Population&)

Assignment operator.

unsigned getChromosomeSize() const

Returns the size of each chromosome.

unsigned getPopulationSize() const

Returns the size of the population.

double operator () (
    const unsigned chromosome,
    const unsigned allele
) const

Returns a copy of an allele for a given chromosome.

Parameters:

chromosome	index of desired chromosome.
allele	index of desired allele.

Returns:

a copy of the allele value.

double& operator () (
    const unsigned chromosome,
    const unsigned allele
)

Returns a reference for an allele for a given chromosome.

Usually used to set the allele value.

Parameters:

chromosome	index of desired chromosome.
allele	index of desired allele.

Returns:

a reference of the allele value.

Chromosome& operator () (unsigned chromosome)

Returns a reference to a chromosome.

Parameters:

chromosome

index of desired chromosome.

Returns:

a reference to chromosome.

fitness_t getBestFitness() const

Returns the best fitness in this population.

fitness_t getFitness(const unsigned i) const

Returns the fitness of chromosome i.

Chromosome& getChromosome(unsigned i)

Returns a reference to the i-th best chromosome.

const Chromosome& getChromosome(const unsigned i) const

Returns a const reference to the i-th best chromosome.

void sortFitness(const Sense sense)

Sorts fitness by its first parameter according to the sense.

Parameters:

sense

Optimization sense.

void setFitness(
    const unsigned chromosome,
    const fitness_t value
)

Sets the fitness of chromosome.

Parameters:

chromosome	index of chromosome.
value	allele value.