生成 遗传算法优化粒子群算法代码
时间: 2023-09-08 22:09:30 浏览: 104
以下是一个简单的遗传算法优化粒子群算法的代码示例(仅供参考):
```python
import random
# 粒子群算法类
class PSO:
def __init__(self, particle_count, dimensions, fitness_func, max_iterations=100, c1=2.0, c2=2.0, w=1.0):
self.particle_count = particle_count
self.dimensions = dimensions
self.fitness_func = fitness_func
self.max_iterations = max_iterations
self.c1 = c1
self.c2 = c2
self.w = w
self.global_best_position = [0.0] * dimensions
self.global_best_fitness = float("inf")
self.particles = []
# 初始化粒子群
for i in range(particle_count):
particle = Particle(dimensions)
self.particles.append(particle)
# 运行粒子群算法
def run(self):
for i in range(self.max_iterations):
for particle in self.particles:
fitness = self.fitness_func(particle.position)
if fitness < particle.best_fitness:
particle.best_fitness = fitness
particle.best_position = particle.position
if fitness < self.global_best_fitness:
self.global_best_fitness = fitness
self.global_best_position = particle.position
for particle in self.particles:
particle.update_velocity(self.global_best_position, self.c1, self.c2, self.w)
particle.update_position()
# 粒子类
class Particle:
def __init__(self, dimensions):
self.position = [random.uniform(-5.0, 5.0) for i in range(dimensions)]
self.velocity = [0.0] * dimensions
self.best_position = self.position
self.best_fitness = float("inf")
# 更新速度
def update_velocity(self, global_best_position, c1, c2, w):
for i in range(len(self.position)):
r1 = random.random()
r2 = random.random()
cognitive_velocity = c1 * r1 * (self.best_position[i] - self.position[i])
social_velocity = c2 * r2 * (global_best_position[i] - self.position[i])
self.velocity[i] = w * self.velocity[i] + cognitive_velocity + social_velocity
# 更新位置
def update_position(self):
for i in range(len(self.position)):
self.position[i] += self.velocity[i]
# 适应度函数
def fitness_func(position):
# TODO: 计算适应度值
return fitness_value
# 遗传算法类
class GA:
def __init__(self, population_size, dimensions, fitness_func, max_generations=100, crossover_rate=0.8, mutation_rate=0.1):
self.population_size = population_size
self.dimensions = dimensions
self.fitness_func = fitness_func
self.max_generations = max_generations
self.crossover_rate = crossover_rate
self.mutation_rate = mutation_rate
self.population = []
self.best_individual = None
self.best_fitness = float("inf")
# 初始化种群
for i in range(population_size):
individual = Individual(dimensions)
self.population.append(individual)
# 运行遗传算法
def run(self):
for generation in range(self.max_generations):
# 计算适应度值
for individual in self.population:
fitness = self.fitness_func(individual.genes)
individual.fitness = fitness
if fitness < self.best_fitness:
self.best_fitness = fitness
self.best_individual = individual
# 选择
new_population = []
total_fitness = sum([individual.fitness for individual in self.population])
for i in range(self.population_size):
roulette_wheel_position = random.uniform(0, total_fitness)
spin_wheel = 0
for individual in self.population:
spin_wheel += individual.fitness
if spin_wheel >= roulette_wheel_position:
new_population.append(individual)
break
# 交叉
for i in range(0, self.population_size - 1, 2):
if random.random() < self.crossover_rate:
crossover_point = random.randint(1, self.dimensions - 2)
new_population[i].genes[crossover_point:], new_population[i+1].genes[crossover_point:] = \
new_population[i+1].genes[crossover_point:], new_population[i].genes[crossover_point:]
# 变异
for individual in new_population:
for i in range(self.dimensions):
if random.random() < self.mutation_rate:
individual.genes[i] = random.uniform(-5.0, 5.0)
self.population = new_population
# 个体类
class Individual:
def __init__(self, dimensions):
self.genes = [random.uniform(-5.0, 5.0) for i in range(dimensions)]
self.fitness = 0
# 运行示例
def main():
pso = PSO(particle_count=50, dimensions=10, fitness_func=fitness_func)
pso.run()
ga = GA(population_size=50, dimensions=10, fitness_func=fitness_func)
ga.run()
if __name__ == "__main__":
main()
```
在上述代码中,PSO 和 GA 分别实现了粒子群算法和遗传算法,并且均包含了相应的粒子/个体类。在主函数中,我们可以分别实例化 PSO 和 GA,并通过调用其 run() 方法来运行算法。请注意,上述代码仅为示例,实际应用中需要根据具体问题进行适当修改。
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