python遗传算法代码
以下是一个简单的遗传算法的Python代码:
```python
import random
# 初始化种
def init_population(population_size, chromosome_length):
population = []
for i in range(population_size):
chromosome = [random.randint(0, 1) for _ in range(chromosome_length)]
population.append(chromosome)
return population
# 计算适应度值
def calculate_fitness(chromosome):
random python fitness = sum(chromosome)
return fitness
# 选择
def selection(population, fitness):
max_fitness = max(fitness)
max_index = fitness.index(max_fitness)
return population[max_index]
# 交叉
def crossover(parent1, parent2):
crossover_point = random.randint(1, len(parent1) - 1)
child1 = parent1[:crossover_point] + parent2[crossover_point:]
child2 = parent2[:crossover_point] + parent1[crossover_point:]
return child1, child2
# 变异
def mutation(chromosome, mutation_rate):
for i in range(len(chromosome)):
if random.random() < mutation_rate:
chromosome[i] = 1 - chromosome[i]
return chromosome
# 遗传算法主函数
def genetic_algorithm(population_size, chromosome_length, mutation_rate, generations):
population = init_population(population_size, chromosome_length)
for _ in range(generations):
fitness = [calculate_fitness(chromosome) for chromosome in population]
new_population = []
for _ in range(population_size // 2):
parent1 = selection(population, fitness)
parent2 = selection(population, fitness)
child1, child2 = crossover(parent1, parent2)
child1 = mutation(child1, mutation_rate)
child2 = mutation(child2, mutation_rate)
new_population.append(child1)
new_population.append(child2)
population = new_population
best_chromosome = selection(population, fitness)
best_fitness = calculate_fitness(best_chromosome)
return best_chromosome, best_fitness
# 测试
population_size = 50
chromosome_length = 10
mutation_rate = 0.01
generations = 100
best_chromosome, best_fitness = genetic_algorithm(population_size, chromosome_length, mutation_rate, generations)
print("Best Chromoso" best_chromosome)
print("Best Fitness:" best_fitness)
```
这段代码实现了一个简单的遗传算法,通过随机生成初始种,利用适应度函数计算每个染体的适应度值,然后进行选择、交叉和变异操作,最终得到最优解。
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