用Matlab写基于遗传算法的TSP问题的代码
时间: 2024-02-22 11:55:12 浏览: 22
以下是基于遗传算法的TSP问题的Matlab代码,代码中采用了简单的交叉和变异操作:
```matlab
%% 遗传算法解决TSP问题
% 城市坐标
x = [0.4000 0.2439 0.1707 0.2293 0.5171 0.8732 0.6878 0.8488 0.6683 0.6195];
y = [0.4439 0.1463 0.2293 0.7610 0.9414 0.6536 0.5219 0.3609 0.2536 0.2634];
% 参数设置
popSize = 50; % 种群大小
maxGen = 200; % 最大迭代次数
pc = 0.8; % 交叉概率
pm = 0.1; % 变异概率
numCity = length(x); % 城市数量
% 初始化种群
pop = zeros(popSize,numCity);
for i = 1:popSize
pop(i,:) = randperm(numCity);
end
% 迭代寻优
for g = 1:maxGen
% 计算适应度
dist = zeros(popSize,1);
for i = 1:popSize
for j = 1:numCity-1
dist(i) = dist(i) + sqrt((x(pop(i,j))-x(pop(i,j+1)))^2+(y(pop(i,j))-y(pop(i,j+1)))^2);
end
dist(i) = dist(i) + sqrt((x(pop(i,numCity))-x(pop(i,1)))^2+(y(pop(i,numCity))-y(pop(i,1)))^2);
end
fitness = 1./dist;
[bestFit,idx] = max(fitness);
bestRoute = pop(idx,:);
% 选择
p = fitness/sum(fitness);
cumP = cumsum(p);
newPop = zeros(popSize,numCity);
for i = 1:popSize
r = rand;
for j = 1:popSize
if r < cumP(j)
newPop(i,:) = pop(j,:);
break;
end
end
end
% 交叉
for i = 1:2:popSize
if rand < pc
idx1 = randi(numCity);
idx2 = randi(numCity);
while idx2 == idx1
idx2 = randi(numCity);
end
if idx1 > idx2
temp = idx1;
idx1 = idx2;
idx2 = temp;
end
child1 = newPop(i,:);
child2 = newPop(i+1,:);
for j = idx1:idx2
temp = child1(j);
child1(j) = child2(j);
child2(j) = temp;
end
newPop(i,:) = child1;
newPop(i+1,:) = child2;
end
end
% 变异
for i = 1:popSize
if rand < pm
idx1 = randi(numCity);
idx2 = randi(numCity);
while idx2 == idx1
idx2 = randi(numCity);
end
temp = newPop(i,idx1);
newPop(i,idx1) = newPop(i,idx2);
newPop(i,idx2) = temp;
end
end
% 更新种群
pop = newPop;
end
% 输出结果
disp(['最短路线:',num2str(bestRoute)]);
disp(['最短距离:',num2str(1/bestFit)]);
```
在运行代码之前,需要先定义城市坐标和一些参数,例如种群大小、最大迭代次数、交叉概率和变异概率等。然后,初始化种群并进行迭代,每次迭代计算种群的适应度,选择适应度高的个体进行交叉和变异操作,最后更新种群。最终输出最优解,即最短路线和最短距离。