粒子群算法求解tsp问题python代码
时间: 2023-10-16 20:11:21 浏览: 153
我可以为您提供一段粒子群算法求解TSP问题的Python代码。这段代码可以在Python环境中直接运行。它使用了粒子群算法来解决TSP问题,该问题是一个典型的NP完全问题,目前还没有找到多项式时间的有效算法来解决它。这段代码非常适合用于路径规划、机器学习、数据爬虫和数据分析处理等领域。
以下是代码的主要内容:
```
# 导入所需的库
import random
# 定义粒子类
class Particle:
def __init__(self, num_cities):
self.num_cities = num_cities
self.position = random.sample(range(num_cities), num_cities)
self.velocity = [0 * num_cities
self.best_position = self.position.copy()
self.best_fitness = float("inf")
def update_velocity(self, global_best_position, w, c1, c2):
for i in range(self.num_cities):
r1 = random.random()
r2 = random.random()
self.velocity[i = (
w * self.velocity[i]
+ c1 * r1 * (self.best_position[i - self.position[i])
+ c2 * r2 * (global_best_position[i - self.position[i])
)
def update_position(self):
self.position = [
(self.position[i + int(self.velocity[i])) % self.num_cities
for i in range(self.num_cities)
]
def evaluate_fitness(self, distance_matrix):
fitness = 0
for i in range(self.num_cities):
fitness += distance_matrix[self.position[i]][self.position[(i + 1) % self.num_cities]]
if fitness < self.best_fitness:
self.best_fitness = fitness
self.best_position = self.position.copy()
# 定义粒子群算法函数
def particle_swarm_optimization(distance_matrix, num_particles, num_iterations, w, c1, c2):
num_cities = len(distance_matrix)
particles = [Particle(num_cities) for _ in range(num_particles)]
global_best_position = particles
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