我方有一基地,经度和纬度为(70,40).假设我方飞机的速度为1000km/h.我方排一飞机从基地出发,侦查完所有目标回到基地,在每一目标侦查时间不计,求飞机所花费的时间? 这是一个典型的TSP问题,下面给出了三种解决方案:
一、模拟退火: clc,clear
load sj.txt %加载敌方100 个目标的数据,数据按照表格中的位置保存在纯文本
文件sj.txt 中
x=sj(:,1:2:8);x=x(;
y=sj(:,2:2:8);y=y(;
sj=[x y]; d1=[70,40];
sj=[d1;sj;d1]; sj=sj*pi/180;
d=zeros(102); %距离矩阵d
for i=1:101
for j=i+1:102
temp=cos(sj(i,1)-sj(j,1))*cos(sj(i,2))*cos(sj(j,2))+sin(sj(i,2))*sin(sj(j,2));
d(i,j)=6370*acos(temp);
end
end
d=d+d';
S0=[];Sum=inf;
rand('state',sum(clock));
for j=1:1000
S=[1 1+randperm(100),102];
temp=0;
for i=1:101
temp=temp+d(S(i),S(i+1));
end
if temp<Sum
S0=S;Sum=temp;
end
end
e=0.1^30;L=20000;at=0.999;T=1;
%退火过程
for k=1
%产生新解
c=2+floor(100*rand(1,2));
c=sort(c);
c1=c(1);c2=c(2);
%计算代价函数值
df=d(S0(c1-1),S0(c2))+d(S0(c1),S0(c2+1))-d(S0(c1-1),S0(c1))-d(S0(c2),S0(c2+1));
%接受准则
if df<0
S0=[S0(1:c1-1),S0(c2:-1:c1),S0(c2+1:102)];
Sum=Sum+df;
elseif exp(-df/T)>rand(1)
S0=[S0(1:c1-1),S0(c2:-1:c1),S0(c2+1:102)];
Sum=Sum+df;
end
T=T*at;
if T<e
break;
end
end
% 输出巡航路径及路径长度
S0,Sum 二、遗传算法: clc,clear
load sj.txt %加载敌方100 个目标的数据
x=sj(:,1:2:8); x=x(;
y=sj(:,2:2:8); y=y(;
sj=[x y]; d1=[70,40];
sj0=[d1;sj;d1]; sj=sj0*pi/180;
d=zeros(102); %距离矩阵d
for i=1:101
for j=i+1:102
temp=cos(sj(i,1)-sj(j,1))*cos(sj(i,2))*cos(sj
(j,2))+sin(sj(i,2))*sin(sj(j,2));
d(i,j)=6370*acos(temp);
end
end
d=d+d';L=102;w=50;dai=100;
%通过改良圈算法选取优良父代A
for k=1:w
c=randperm(100);
c1=[1,c+1,102];
flag=1;
while flag>0
flag=0;
for m=1-3
for n=m+2-1
if d(c1(m),c1(n))+d(c1(m+1),c1(n+1))<d(c1(m),c1(m
+1))+d(c1(n),c1(n+1))
flag=1;
c1(m+1:n)=c1(n:-1:m+1);
end
end
end
end
J(k,c1)=1:102;
end
J=J/102;
J(:,1)=0;J(:,102)=1;
rand('state',sum(clock));
%遗传算法实现过程
A=J;
for k=1:dai %产生0~1 间随机数列进行编码
B=A;
c=randperm(w);
%交配产生子代B
for i=1:2:w
F=2+floor(100*rand(1));
temp=B(c(i),F:102);
B(c(i),F:102)=B(c(i+1),F:102);
B(c(i+1),F:102)=temp;
end
%变异产生子代C
by=find(rand(1,w)<0.1);
if length(by)==0
by=floor(w*rand(1))+1;
end
C=A(by,;
L3=length(by);
for j=13
bw=2+floor(100*rand(1,3));
bw=sort(bw);
C(j,=C(j,[1:bw(1)-1,bw(2)+1:bw(3),bw(1):bw(2),bw
(3)+1:102]);
end
G=[A;B;C];
TL=size(G,1);
%在父代和子代中选择优良品种作为新的父代
[dd,IX]=sort(G,2);temp(1:TL)=0;
for j=1:TL
for i=1:101
temp(j)=temp(j)+d(IX(j,i),IX(j,i+1));
end
end
[DZ,IZ]=sort(temp);
A=G(IZ(1:w),;
end
path=IX(IZ(1),
long=DZ(1)
toc
xx=sj0(path,1);yy=sj0(path,2);
plot(xx,yy,'-o') 三、改进遗传算法:
clc,clear
load sj.txt %加载敌方100 个目标的数据
x=sj(:,1:2:8);x=x(;
y=sj(:,2:2:8);y=y(;
sj=[x y];
d1=[70,40];
sj=[d1;sj;d1];
sj=sj*pi/180;
d=zeros(102); %距离矩阵d
for i=1:101
for j=i+1:102
temp=cos(sj(i,1)-sj(j,1))*cos(sj(i,2))*cos(sj
(j,2))+sin(sj(i,2))*sin(sj(j,2));
d(i,j)=6370*acos(temp);
end
end
d=d+d';L=102;w=50;dai=100;
%通过改良圈算法选取优良父代A
for k=1:w
c=randperm(100);
c1=[1,c+1,102];
flag=1;
while flag>0
flag=0;
for m=1-3
for n=m+2-1
if d(c1(m),c1(n))+d(c1(m+1),c1(n+1))<d(c1(m),c1(m
+1))+d(c1(n),c1(n+1))
flag=1;
c1(m+1:n)=c1(n:-1:m+1);
end
end
end
end
J(k,c1)=1:102;
end
J=J/102;
J(:,1)=0;J(:,102)=1;
rand('state',sum(clock));
%遗传算法实现过程
A=J;
for k=1:dai %产生0~1 间随机数列进行编码
B=A;
%交配产生子代B
for i=1:2:w
ch0=rand;ch(1)=4*ch0*(1-ch0);
for j=2:50
ch(j)=4*ch(j-1)*(1-ch(j-1));
end
ch=2+floor(100*ch);
temp=B(i,ch);
B(i,ch)=B(i+1,ch);
B(i+1,ch)=temp;
end
%变异产生子代C
by=find(rand(1,w)<0.1);
if length(by)==0
by=floor(w*rand(1))+1;
end
C=A(by,;
L3=length(by);
for j=13
bw=2+floor(100*rand(1,3));
bw=sort(bw);
C(j,=C(j,[1:bw(1)-1,bw(2)+1:bw(3),bw(1):bw(2),bw
(3)+1:102]);
end
G=[A;B;C];
TL=size(G,1);
%在父代和子代中选择优良品种作为新的父代
[dd,IX]=sort(G,2);temp(1:TL)=0;
for j=1:TL
for i=1:101
temp(j)=temp(j)+d(IX(j,i),IX(j,i+1));
end
end
[DZ,IZ]=sort(temp);
A=G(IZ(1:w),;
end
path=IX(IZ(1),
long=DZ(1) matlab源程序见附件
实验运行结果如图
——摘自《数学建模算法与应用》司守奎主编