写一个粒子群算法解决TSP问题的PYTHON代码
时间: 2024-06-09 13:07:33 浏览: 145
好的,下面是一个简单的粒子群算法解决TSP问题的Python代码:
```python
import random
import math
# 定义TSP问题的数据
tsp_data = [
(200, 800),
(3600, 2300),
(3100, 3300),
(4700, 5750),
(5400, 5750),
(5608, 7103),
(4493, 7102),
(3600, 6950),
(3100, 7250),
(4700, 8450),
(5400, 8450),
(5610, 10053),
(4492, 10052),
(3600, 10800),
(3100, 11100),
(4700, 12300),
(5400, 12300),
(6650, 10803),
(6908, 9653),
(7510, 11200),
(7600, 7050),
(6650, 6050),
(6900, 4650),
(7510, 5000),
(7600, 2000),
(6650, 1500),
(6900, 1000),
(7510, 200),
(3600, 200),
(3100, 1000),
(4700, 1750),
(5400, 1750),
(5608, 3103),
(4493, 3102),
(3600, 2500),
(3100, 2700),
(4700, 3850),
(5400, 3850),
(5610, 5053),
(4492, 5052),
(3600, 4500),
(3100, 4700),
(4700, 6050),
(5400, 6050),
(6650, 5053),
(6908, 3703),
(7510, 4500),
(7600, 2500),
]
# 定义粒子群算法的参数
num_particles = 50
max_iterations = 1000
c1 = 1.5
c2 = 1.5
w = 0.7
# 计算两个点之间的距离
def distance(p1, p2):
return math.sqrt((p1[0] - p2[0]) ** 2 + (p1[1] - p2[1]) ** 2)
# 计算一个路线的总距离
def total_distance(route):
return sum(distance(route[i], route[i+1]) for i in range(len(route)-1)) + distance(route[0], route[-1])
# 初始化粒子群
particles = []
best_particle = None
best_particle_fitness = float('inf')
for i in range(num_particles):
particle = random.sample(tsp_data, len(tsp_data))
fitness = total_distance(particle)
particles.append({'route': particle, 'fitness': fitness, 'velocity': [0] * len(tsp_data)})
if fitness < best_particle_fitness:
best_particle = particle
best_particle_fitness = fitness
# 开始迭代
for i in range(max_iterations):
for j in range(num_particles):
particle = particles[j]
velocity = particle['velocity']
route = particle['route']
fitness = particle['fitness']
personal_best = route.copy()
# 更新粒子的速度和位置
for k in range(len(route)):
velocity[k] = w * velocity[k] + c1 * random.random() * (personal_best[k][0] - route[k][0]) \
+ c2 * random.random() * (best_particle[k][0] - route[k][0])
route[k] = (route[k][0] + velocity[k], route[k][1])
# 计算新的路线的总距离
new_fitness = total_distance(route)
# 更新粒子的个人最优解和全局最优解
if new_fitness < fitness:
particle['fitness'] = new_fitness
particle['route'] = route
personal_best = route.copy()
if new_fitness < best_particle_fitness:
best_particle_fitness = new_fitness
best_particle = route.copy()
print("最优解路线:", best_particle)
print("最优解总距离:", best_particle_fitness)
```
在这个代码中,我们定义了一个TSP问题的数据,即每个城市的坐标。然后我们定义了粒子群算法的参数,包括粒子数量、最大迭代次数以及加速度系数等。
在初始化粒子群的时候,我们随机生成了每个粒子的初始路线,并计算了其总距离。然后在每次迭代中,我们更新每个粒子的速度和位置,并计算新的路线的总距离。如果新的路线比个人最优解或全局最优解更优,则更新个人最优解和全局最优解。
最后,我们输出了最优解的路线和总距离。
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