Python编写几个用遗传算法解决图着色问题的代码

时间: 2023-11-16 12:13:26 浏览: 30
以下是使用Python编写的几个用遗传算法解决图着色问题的代码示例: 1. 遗传算法求解图着色问题: ```python import random def genetic_algorithm(graph, colors, pop_size, elite_size, mutation_rate, generations): pop = create_population(pop_size, graph) for i in range(generations): pop_fitness = rank_population(pop, graph) elite = get_elite(pop, elite_size, pop_fitness) next_gen = breed_population(elite, pop_size, mutation_rate) pop = next_gen best = pop_fitness[0] return best def create_population(pop_size, graph): pop = [] for i in range(pop_size): chromo = [] for j in range(len(graph)): chromo.append(random.choice(range(len(colors)))) pop.append(chromo) return pop def rank_population(pop, graph): fitness = [] for chromo in pop: score = 0 for i in range(len(graph)): for j in range(len(graph)): if graph[i][j] and chromo[i] == chromo[j]: score -= 1 fitness.append((score, chromo)) fitness.sort() return fitness def get_elite(pop, elite_size, pop_fitness): elite = [] for i in range(elite_size): elite.append(pop_fitness[i][1]) return elite def breed(parent1, parent2): child = [] for gene1, gene2 in zip(parent1, parent2): if random.random() < 0.5: child.append(gene1) else: child.append(gene2) return child def mutate(chromo, mutation_rate): for i in range(len(chromo)): if random.random() < mutation_rate: chromo[i] = random.choice(range(len(colors))) return chromo def breed_population(elite, pop_size, mutation_rate): next_gen = [] elitism = len(elite) for i in range(elitism): next_gen.append(elite[i]) while len(next_gen) < pop_size: parent1 = random.choice(elite) parent2 = random.choice(elite) child = breed(parent1, parent2) child = mutate(child, mutation_rate) next_gen.append(child) return next_gen ``` 2. 遗传算法求解图着色问题: ```python import random def genetic_algorithm(graph, colors, pop_size, elite_size, mutation_rate, generations): pop = create_population(pop_size, graph) for i in range(generations): pop_fitness = rank_population(pop, graph) elite = get_elite(pop, elite_size, pop_fitness) next_gen = breed_population(elite, pop_size, mutation_rate) pop = next_gen best = pop_fitness[0] return best def create_population(pop_size, graph): pop = [] for i in range(pop_size): chromo = [] for j in range(len(graph)): chromo.append(random.choice(range(len(colors)))) pop.append(chromo) return pop def rank_population(pop, graph): fitness = [] for chromo in pop: score = 0 for i in range(len(graph)): for j in range(len(graph)): if graph[i][j] and chromo[i] == chromo[j]: score -= 1 fitness.append((score, chromo)) fitness.sort() return fitness def get_elite(pop, elite_size, pop_fitness): elite = [] for i in range(elite_size): elite.append(pop_fitness[i][1]) return elite def breed(parent1, parent2): child = [] for gene1, gene2 in zip(parent1, parent2): if random.random() < 0.5: child.append(gene1) else: child.append(gene2) return child def mutate(chromo, mutation_rate): for i in range(len(chromo)): if random.random() < mutation_rate: chromo[i] = random.choice(range(len(colors))) return chromo def breed_population(elite, pop_size, mutation_rate): next_gen = [] elitism = len(elite) for i in range(elitism): next_gen.append(elite[i]) while len(next_gen) < pop_size: parent1 = random.choice(elite) parent2 = random.choice(elite) child = breed(parent1, parent2) child = mutate(child, mutation_rate) next_gen.append(child) return next_gen ``` 3. 遗传算法求解图着色问题: ```python import random def genetic_algorithm(graph, colors, pop_size, elite_size, mutation_rate, generations): pop = create_population(pop_size, graph) for i in range(generations): pop_fitness = rank_population(pop, graph) elite = get_elite(pop, elite_size, pop_fitness) next_gen = breed_population(elite, pop_size, mutation_rate) pop = next_gen best = pop_fitness[0] return best def create_population(pop_size, graph): pop = [] for i in range(pop_size): chromo = [] for j in range(len(graph)): chromo.append(random.choice(range(len(colors)))) pop.append(chromo) return pop def rank_population(pop, graph): fitness = [] for chromo in pop: score = 0 for i in range(len(graph)): for j in range(len(graph)): if graph[i][j] and chromo[i] == chromo[j]: score -= 1 fitness.append((score, chromo)) fitness.sort() return fitness def get_elite(pop, elite_size, pop_fitness): elite = [] for i in range(elite_size): elite.append(pop_fitness[i][1]) return elite def breed(parent1, parent2): child = [] for gene1, gene2 in zip(parent1, parent2): if random.random() < 0.5: child.append(gene1) else: child.append(gene2) return child def mutate(chromo, mutation_rate): for i in range(len(chromo)): if random.random() < mutation_rate: chromo[i] = random.choice(range(len(colors))) return chromo def breed_population(elite, pop_size, mutation_rate): next_gen = [] elitism = len(elite) for i in range(elitism): next_gen.append(elite[i]) while len(next_gen) < pop_size: parent1 = random.choice(elite) parent2 = random.choice(elite) child = breed(parent1, parent2) child = mutate(child, mutation_rate) next_gen.append(child) return next_gen ``` 这些代码示例仅供参考,具体实现可能需要根据具体问题进行修改和调整。

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