蚁群系统ACS算法求解TSP问题MATLAB代码
时间: 2023-12-21 08:07:42 浏览: 99
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以下是使用MATLAB实现ACS算法求解TSP问题的示例代码:
```matlab
% 设置城市坐标
city_position = [0.4000 0.4439; 0.2439 0.1463; 0.1707 0.2293; 0.2293 0.7610; 0.5171 0.9414;
0.8732 0.6536; 0.6878 0.5219; 0.8488 0.3609; 0.6683 0.2536; 0.6195 0.2634];
% 计算城市之间的距离矩阵
num_cities = size(city_position, 1);
dist_mat = zeros(num_cities);
for i = 1:num_cities
for j = 1:num_cities
dist_mat(i, j) = sqrt(sum((city_position(i, :) - city_position(j, :)).^2));
end
end
% 设置算法参数
num_ants = 10; % 蚂蚁数量
num_iter = 100; % 迭代次数
alpha = 1; % 信息素重要程度因子
beta = 5; % 启发式因子
rho = 0.5; % 信息素挥发因子
Q = 1; % 信息素增量常数
pheromone_mat = ones(num_cities, num_cities); % 初始化信息素矩阵
% 迭代过程
best_path = zeros(1, num_cities);
best_path_length = Inf;
for iter = 1:num_iter
% 初始化蚂蚁位置
ant_position = zeros(num_ants, 1);
ant_path = zeros(num_ants, num_cities);
for i = 1:num_ants
ant_position(i) = randi(num_cities);
ant_path(i, 1) = ant_position(i);
end
% 蚂蚁移动
for k = 2:num_cities
for i = 1:num_ants
% 计算概率分布
prob = zeros(num_cities, 1);
visited_cities = ant_path(i, 1:k-1);
unvisited_cities = setdiff(1:num_cities, visited_cities);
for j = unvisited_cities
prob(j) = pheromone_mat(ant_position(i), j)^alpha * (1/dist_mat(ant_position(i), j))^beta;
end
prob = prob/sum(prob);
% 选择下一个城市
next_city = randsrc(1, 1, [unvisited_cities; prob']);
ant_position(i) = next_city;
ant_path(i, k) = next_city;
end
end
% 计算路径长度
path_length = zeros(num_ants, 1);
for i = 1:num_ants
for j = 2:num_cities
path_length(i) = path_length(i) + dist_mat(ant_path(i, j-1), ant_path(i, j));
end
path_length(i) = path_length(i) + dist_mat(ant_path(i, num_cities), ant_path(i, 1));
% 更新最优路径
if path_length(i) < best_path_length
best_path = ant_path(i, :);
best_path_length = path_length(i);
end
end
% 更新信息素
delta_pheromone_mat = zeros(num_cities, num_cities);
for i = 1:num_ants
for j = 2:num_cities
delta_pheromone_mat(ant_path(i, j-1), ant_path(i, j)) = delta_pheromone_mat(ant_path(i, j-1), ant_path(i, j)) + Q/path_length(i);
end
delta_pheromone_mat(ant_path(i, num_cities), ant_path(i, 1)) = delta_pheromone_mat(ant_path(i, num_cities), ant_path(i, 1)) + Q/path_length(i);
end
pheromone_mat = (1-rho)*pheromone_mat + delta_pheromone_mat;
end
% 输出结果
disp('最优路径:');
disp(best_path);
disp(['最优路径长度:', num2str(best_path_length)]);
```
需要注意的是,该代码中的城市坐标是手动设置的,实际应用中需要根据具体情况来设置城市坐标。另外,算法中的参数值也需要根据具体情况进行调整。
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