MH-P2/src/memetic_algorithm.py
2021-06-22 00:21:14 +02:00

60 lines
2.4 KiB
Python

from genetic_algorithm import *
from local_search import local_search
from copy import deepcopy
def get_best_indices(n, population):
select_population = deepcopy(population)
best_elements = []
for _ in range(n):
best_index, _ = get_best_elements(select_population)
best_elements.append(best_index)
select_population.pop(best_index)
return best_elements
def replace_elements(current_population, new_population, indices):
for item in indices:
current_population[item] = new_population[item]
return current_population
def run_local_search(n, data, population, mode, probability=0.1):
neighbourhood = []
if mode == "all":
for individual in population:
neighbourhood.append(local_search(individual, n, data))
new_population = neighbourhood
elif mode == "random":
expected_individuals = len(population) * probability
indices = []
for _ in range(expected_individuals):
random_index = randint(len(population))
random_individual = population[random_index]
neighbourhood.append(local_search(random_individual, n, data))
indices.append(random_index)
new_population = replace_elements(population, neighbourhood, indices)
else:
expected_individuals = len(population) * probability
best_indices = get_best_indices(n=expected_individuals, population=population)
for element in best_indices:
neighbourhood.append(local_search(population[element], n, data))
new_population = replace_elements(population, neighbourhood, best_indices)
return new_population
def memetic_algorithm(n, m, data, hybridation, max_iterations=100000):
population = [generate_individual(n, m, data) for _ in range(n)]
population = evaluate_population(population, data)
for i in range(max_iterations):
if i % 10 == 0:
population = run_local_search(n, data, population, mode=hybridation)
i += 5
parents = select_parents(population, n, mode="stationary")
offspring = crossover(mode="position", parents=parents, m=m)
offspring = mutate(offspring, n, data)
population = replace_population(population, offspring, mode="stationary")
population = evaluate_population(population, data)
best_index, _ = get_best_elements(population)
return population[best_index]