def invasive_weed(self, iteration, iter_max, e, sigma_init, sigma_fin,
N_min, N_max, member, **kwargs):
"""Add new individuals to the population via methods of invasive weed algorithm."""
seeds = []
sigma = ((iter_max - iteration) / iter_max)
sigma = pow(sigma, e)
sigma = sigma * (sigma_init - sigma_fin) + sigma_fin
fitness_max = self.current_population[-1].fitness
fitness_min = self.current_population[0].fitness
ratio = (fitness_max - member.fitness) / (fitness_max - fitness_min)
N = int(N_min + (N_max - N_min) * ratio)
for _ in range(N):
seed = Chromosome(self.chromosome_size, self.fitness_function)
for i in range(self.chromosome_size):
random_value = random.uniform(member.genes[i] - sigma,
member.genes[i] + sigma)
seed.genes[i] = random_value
seed.resize_invalid_genes()
seed.calculate_fitness(**kwargs)
seeds.append(seed)
return seeds
def add_new_individual(self, *args, **kwargs):
"""Add new individual with fitness value to the current population."""
individual = Chromosome(self.chromosome_size, self.fitness_function)
individual.calculate_fitness(**kwargs)
return individual
def create_initial_population(self):
"""Create members of the first population randomly."""
for _ in range(self.pop_size):
individual = Chromosome(self.chromosome_size,
self.fitness_function)
if not self.pool:
individual.calculate_fitness()
self.add_individual_to_pop(individual)
if self.pool:
p = Pool(self.pool_size)
manager = Manager()
lock = manager.Lock()
counter = manager.Value('i', 0)
def pool_function(inside_lock, inside_counter, inside_member):
inside_lock.acquire()
inside_counter.value += 1
inside_lock.release()
fitness_value = inside_member.calculate_fitness(
gpu=inside_counter.value % 4)
return fitness_value
func = partial(pool_function, lock, counter)
fitness_values = p.map(func, self.current_population[:])
for value, member in zip(fitness_values,
self.current_population[:]):
member.fitness = value
p.terminate()
def crossover(self, selection_function, *args, **kwargs):
"""Add new individuals to the population with crossover."""
child_1 = Chromosome(self.chromosome_size, self.fitness_function)
child_2 = Chromosome(self.chromosome_size, self.fitness_function)
parent_1 = selection_function(self)
parent_2 = selection_function(self)
crossover_index = random.randrange(1, self.chromosome_size - 1)
child_1.genes = np.concatenate((parent_1.genes[:crossover_index],
parent_2.genes[crossover_index:]),
axis=None)
child_2.genes = np.concatenate((parent_2.genes[:crossover_index],
parent_1.genes[crossover_index:]),
axis=None)
child_1.calculate_fitness(**kwargs)
child_2.calculate_fitness(**kwargs)
return [child_1, child_2]