trp.asv

tsp问题用神经网络方法解决

%d=[0 10 15 6 2;10 0 8 13 9;15 8 0 20 15;6 13 20 0 5;2 9 15 5 0];
%t0=10;
% tf=0.7;
% [f,T]=trp(d,t0,tf)
function[f,T]=trp(d,t0,tf)0
[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;
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-1));
    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;