Add memetic algorithm prototype
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from numpy.random import choice, seed
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from genetic_algorithm import *
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from local_search import local_search
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def get_first_random_solution(m, data):
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seed(42)
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random_indexes = choice(len(data.index), size=m, replace=False)
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return data.loc[random_indexes]
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def run_local_search(n, m, data, individual):
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pass
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def element_in_dataframe(solution, element):
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duplicates = solution.query(
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f"(source == {element.source} and destination == {element.destination}) or (source == {element.destination} and destination == {element.source})"
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)
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return not duplicates.empty
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def replace_worst_element(previous, data):
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solution = previous.copy()
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worst_index = solution["distance"].astype(float).idxmin()
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random_element = data.sample().squeeze()
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while element_in_dataframe(solution=solution, element=random_element):
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random_element = data.sample().squeeze()
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solution.loc[worst_index] = random_element
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return solution, worst_index
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def get_random_solution(previous, data):
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solution, worst_index = replace_worst_element(previous, data)
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previous_worst_distance = previous["distance"].loc[worst_index]
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while solution.distance.loc[worst_index] <= previous_worst_distance:
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solution, _ = replace_worst_element(previous=solution, data=data)
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return solution
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def explore_neighbourhood(element, data, max_iterations=100000):
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neighbourhood = []
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neighbourhood.append(element)
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for _ in range(max_iterations):
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previous_solution = neighbourhood[-1]
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neighbour = get_random_solution(previous=previous_solution, data=data)
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neighbourhood.append(neighbour)
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return neighbour
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def memetic_algorithm(m, data):
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first_solution = get_first_random_solution(m=m, data=data)
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best_solution = explore_neighbourhood(
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element=first_solution, data=data, max_iterations=100
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)
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return best_solution
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def memetic_algorithm(n, m, data, hybridation, max_iterations=100000):
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population = [generate_individual(n, m, data) for _ in range(n)]
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population = evaluate_population(population, data)
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for i in range(max_iterations):
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if i % 10 == 0:
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best_index, _ = get_best_elements(population)
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run_local_search(n, m, data, individual=population[best_index])
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parents = select_parents(population, n, mode="stationary")
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offspring = crossover(mode="uniform", parents=parents, m=m)
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offspring = mutate(offspring, n, data)
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population = replace_population(population, offspring, mode="stationary")
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population = evaluate_population(population, data)
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best_index, _ = get_best_elements(population)
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return population[best_index]
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