def create_population(self,
population_size: int,
individual_size: int,
gene_factory: GeneFactory,
mutation_rate=0.01):
"""
Creates a new population for the engine.
The new population is then sorted according to the individual's fitness
Args:
mutation_rate:
population_size:
The number of individuals of the population.
individual_size:
The number of genes of each member.
gene_factory:
The factory to create the genes of each individual
"""
self.__population = Individual.create(population_size, individual_size,
gene_factory, mutation_rate,
*self.__factory_generator_args)
for member in self.__population:
member.compute_fitness_using(self.__fitness_function,
*self.__fitness_function_args)
self.__population.sort()
self.__fittest = self.__population[-1]
def test_creation_with_characters(str_gene_factory: GeneFactory[str]):
individuals = Individual.create(number_of_individuals=100, number_of_genes=10,
gene_factory=str_gene_factory)
assert len(individuals) == 100
for individual in individuals:
assert len(individual.genes) == 10
for gene in individual.genes:
assert gene in string.ascii_lowercase
def test_mutation():
gene_factory = GeneFactory[str]()
gene_factory.generator = lambda: Random(8000).choice(string.ascii_lowercase)
individual = Individual()
individual.random_generator = Random(8000)
individual.genes = "abcd"
individual.gene_factory = gene_factory
individual.mutation_rate = 0.5
mutated_i = individual.mutate()
assert mutated_i.genes == list("sbsd")
def test_word_guess(str_gene_factory: GeneFactory[str]):
individuals = Individual.create(number_of_individuals=100000, number_of_genes=3,
gene_factory=str_gene_factory)
def fitness_function(word: List[str]) -> float:
return sum([1 if word[i] == "cat"[i] else 0 for i in range(0, 3)])
fittest_individual = individuals[0]
for individual in individuals:
individual.compute_fitness_using(fitness_function)
if individual.fitness > fittest_individual.fitness:
fittest_individual = individual
assert fittest_individual.fitness == 3
def couple() -> Tuple[Individual, Individual]:
c = (Individual(), Individual())
c[0].genes = "abcd"
c[1].genes = "defg"
return c
def mutate(self, individual: Individual, *args) -> Individual:
"""Mutates an individual and returns the result of the mutation."""
individual.random_generator = self.random_generator
return individual.mutate(*args)
def crossover(self, partner_a: Individual, partner_b: Individual,
*args) -> Individual:
"""Performs a crossover between two individuals and returns the offspring."""
partner_a.random_generator = self._random_generator
return partner_a.crossover(partner_b, *args)