from numpy.random import choice, seed def get_first_random_solution(n, m): seed(42) solution = zeros(shape=n, dtype=bool) random_indices = choice(n, size=m, replace=False) put(solution, ind=random_indices, v=True) return solution def element_in_dataframe(solution, element): duplicates = solution.query( f"(source == {element.source} and destination == {element.destination}) or (source == {element.destination} and destination == {element.source})" ) return not duplicates.empty def replace_worst_element(previous, data): solution = previous.copy() worst_index = solution["distance"].astype(float).idxmin() random_element = data.sample().squeeze() while element_in_dataframe(solution=solution, element=random_element): random_element = data.sample().squeeze() solution.loc[worst_index] = random_element return solution, worst_index def get_random_solution(previous, data): solution, worst_index = replace_worst_element(previous, data) previous_worst_distance = previous["distance"].loc[worst_index] while solution.distance.loc[worst_index] <= previous_worst_distance: solution, _ = replace_worst_element(previous=solution, data=data) return solution def explore_neighbourhood(element, data, max_iterations=100000): neighbourhood = [] neighbourhood.append(element) for _ in range(max_iterations): previous_solution = neighbourhood[-1] neighbour = get_random_solution(previous=previous_solution, data=data) neighbourhood.append(neighbour) return neighbour def genetic_algorithm(n, m, data): first_solution = get_first_random_solution(n=n, m=m) best_solution = explore_neighbourhood( element=first_solution, data=data, max_iterations=100 ) return best_solution