'Ant' object has no attribute 'id'
时间: 2023-06-22 08:38:55 浏览: 65
非常抱歉,我之前的代码里有一个错误。在 `Ant` 类中没有定义 `id` 属性,所以调用 `ant.id` 时会出现 `'Ant' object has no attribute 'id'` 的错误。下面是修改后的代码,已经添加了 `id` 属性:
```python
import random
import numpy as np
# 非对称TSP问题的距离矩阵
distances = np.array([[0, 3, 4, 2],
[2, 0, 5, 6],
[4, 5, 0, 7],
[3, 2, 6, 0]])
# 蚂蚁数量
num_ants = 5
# 信息素初始值
pheromone = np.ones(distances.shape) / len(distances)
# 信息素挥发率
evaporation_rate = 0.5
# 信息素增强强度
alpha = 1
# 启发式信息强度
beta = 1
# 最大迭代次数
max_iterations = 100
# 记录每只蚂蚁走过的路径长度
ant_distances = np.zeros(num_ants)
# 记录最短路径长度和路径
best_distance = float('inf')
best_path = []
# 蚂蚁类
class Ant:
def __init__(self, start_city, id):
self.path = [start_city]
self.visited = set([start_city])
self.id = id
def choose_next_city(self):
current_city = self.path[-1]
unvisited_cities = set(range(len(distances))) - self.visited
if not unvisited_cities:
return None
probabilities = [pheromone[current_city][next_city]**alpha *
(1.0/distances[current_city][next_city])**beta
for next_city in unvisited_cities]
probabilities = np.array(probabilities) / sum(probabilities)
next_city = np.random.choice(list(unvisited_cities), p=probabilities)
self.path.append(next_city)
self.visited.add(next_city)
return next_city
def update_pheromone(self):
for i in range(len(self.path)-1):
current_city, next_city = self.path[i], self.path[i+1]
pheromone[current_city][next_city] += 1.0 / ant_distances[self.id]
# 初始化蚂蚁
ants = [Ant(random.randint(0, len(distances)-1), i) for i in range(num_ants)]
# 迭代
for iteration in range(max_iterations):
# 蚂蚁走路
for ant in ants:
while ant.choose_next_city() is not None:
pass
ant_distances[ant.id] = sum(distances[ant.path[i]][ant.path[i+1]] for i in range(len(ant.path)-1))
if ant_distances[ant.id] < best_distance:
best_distance = ant_distances[ant.id]
best_path = ant.path
# 更新信息素
pheromone *= evaporation_rate
for ant in ants:
ant.update_pheromone()
# 重置蚂蚁
ants = [Ant(random.randint(0, len(distances)-1), i) for i in range(num_ants)]
print('最短路径长度:', best_distance)
print('最短路径:', best_path)
```
在修改后的代码中,我添加了一个 `id` 参数,用于给每个蚂蚁分配一个唯一的标识符。这样,在更新信息素时,就可以根据每只蚂蚁的 `id` 属性来找到对应的路径长度,从而避免了之前的错误。
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