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# Author: Simon Blanke |
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# Email: [email protected] |
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# License: MIT License |
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import random |
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import numpy as np |
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from ._evolutionary_algorithm import EvolutionaryAlgorithmOptimizer |
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from ._individual import Individual |
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class GeneticAlgorithmOptimizer(EvolutionaryAlgorithmOptimizer): |
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name = "Genetic Algorithm" |
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_name_ = "genetic_algorithm" |
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__name__ = "GeneticAlgorithmOptimizer" |
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optimizer_type = "population" |
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computationally_expensive = False |
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def __init__( |
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self, |
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*args, |
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population=10, |
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offspring=10, |
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crossover="discrete-recombination", |
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n_parents=2, |
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mutation_rate=0.5, |
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crossover_rate=0.5, |
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**kwargs |
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): |
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super().__init__(*args, **kwargs) |
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self.population = population |
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self.offspring = offspring |
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self.crossover = crossover |
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self.n_parents = n_parents |
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self.mutation_rate = mutation_rate |
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self.crossover_rate = crossover_rate |
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self.individuals = self._create_population(Individual) |
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self.optimizers = self.individuals |
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self.offspring_l = [] |
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def fittest_parents(self): |
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fittest_parents_f = 0.5 |
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self.sort_pop_best_score() |
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n_fittest = int(len(self.pop_sorted) * fittest_parents_f) |
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best_l = self.pop_sorted[:n_fittest] |
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worst_l = self.pop_sorted[n_fittest:] |
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if 0.01 >= random.random(): |
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best_l[random.randint(0, len(best_l) - 1)] = random.choice(worst_l) |
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return best_l |
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def _crossover(self): |
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fittest_parents = self.fittest_parents() |
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selected_parents = random.sample(fittest_parents, self.n_parents) |
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for _ in range(self.offspring): |
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parent_pos_l = [parent.pos_new for parent in selected_parents] |
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offspring = self.discrete_recombination(parent_pos_l) |
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offspring = self._constraint_loop(offspring) |
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self.offspring_l.append(offspring) |
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def _constraint_loop(self, position): |
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while True: |
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if self.conv.not_in_constraint(position): |
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return position |
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position = self.p_current.move_climb(position, epsilon_mod=0.3) |
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@EvolutionaryAlgorithmOptimizer.track_new_pos |
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def init_pos(self): |
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nth_pop = self.nth_trial % len(self.individuals) |
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self.p_current = self.individuals[nth_pop] |
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return self.p_current.init_pos() |
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View Code Duplication |
@EvolutionaryAlgorithmOptimizer.track_new_pos |
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def iterate(self): |
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n_ind = len(self.individuals) |
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if n_ind == 1: |
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self.p_current = self.individuals[0] |
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return self.p_current.iterate() |
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self.sort_pop_best_score() |
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rnd_int = random.randint(0, len(self.pop_sorted) - 1) |
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self.p_current = self.pop_sorted[rnd_int] |
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total_rate = self.mutation_rate + self.crossover_rate |
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rand = np.random.uniform(low=0, high=total_rate) |
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if rand <= self.mutation_rate: |
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return self.p_current.iterate() |
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else: |
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if not self.offspring_l: |
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self._crossover() |
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self.p_current.pos_new = self.offspring_l.pop(0) |
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return self.p_current.pos_new |
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@EvolutionaryAlgorithmOptimizer.track_new_score |
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def evaluate(self, score_new): |
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self.p_current.evaluate(score_new) |
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