matlab解决TSP问题（货郎担问题，旅行商问题）的模拟退火算法

Posted 2022-08-24 之墨_

TSP问题（货郎担问题，旅行商问题）的模拟退火算法

function [f,T]=TSPSA(d,t0,tf)
%TSP问题（货郎担问题，旅行商问题）的模拟退火算法通用malab源程序
% f目标最优值,T最优路线,d距离矩阵,t0初始温度,tf结束温度
[m,n]=size(d);
L=100*n;
t=t0;
pi0=1:n;
min_f=0;
for k=1：n-1
min_f=min_f+d(pi0(k),pi0(k+1));
end
min_f=min_f+d(pi0(n),pi0(1));
p_min=pi0;
while t>tf
for k=1:L;
kk=rand;
[d_f,pi_1]=exchange_2(pi0,d);
r_r=rand; 
if d_f<0
pi0=pi_1;
elseif exp(d_f/t)>r_r
pi0=pi_1;
else
pi0=pi0;
end
end
f_temp=0;
for k=1：n-1
f_temp=f_temp+d(pi0(k),pi0(k+1));
end
f_temp=f_temp+d(pi0(n),pi0(1));
if min_f>f_temp
min_f=f_temp;
p_min=pi0;
end
t=0.87*t;
end
f=min_f;
T=p_min;
%aiwa要调用的子程序,用于产生新解
function [d_f,pi_r]=exchange_2(pi0,d)
[m,n]=size(d);
clear m;
u=rand;
u=u*(n-2);
u=round(u);
if u<2
u=2;
end
if u>n-2
u=n-2;
end
v=rand;
v=v*(n-u+1);
v=round(v);
if v<1
v=1;
end
v=u+v;
if v>n
v=n;
end
pi_1(u)=pi0(v);
pi_1(v)=pi0(u);
if u>1
for k=1：u-1
pi_1(k)=pi0(k);
end
end
if v>(u+1)
for k=1：v-u-1
pi_1(u+k)=pi0(v-k);
end
end
if v<n
for k=(v+1):n
pi_1(k)=pi0(k);
end
end
d_f=0;
if v<n
d_f=d(pi0(u-1),pi0(v))+d(pi0(u),pi0(v+1));
for k=(u+1):n
d_f=d_f+d(pi0(k),pi0(k-1));
end
d_f=d_f-d(pi0(u-1),pi0(u))-d(pi0(v),pi0(v+1));
for k=(u+1):n
d_f=d_f-d(pi0(k-1),pi0(k));
end
else
d_f=d(pi0(u-1),pi0(v))+d(pi0(u),pi0(1))-d(pi0(u-1),pi0(u))-d(pi0(v),pi0(1));
for k=(u+1):n
d_f=d_f+d(pi0(k),pi0(k-1));
end
for k=(u+1):n
d_f=d_f-d(pi0(k-1),pi0(k));
end
end
pi_r=pi_1;