antcity

蚁群优化算法matlab实现

主函数：

clear

clc

m=5;%种群规模

[pop,pheromone]=initialization(m)%分别求出初始矩阵与信息素

antfirstcity=firstcity(m)%每只蚂蚁随机选择出发的城市

antcity=lectcity(pop,m,pheromone,antfirstcity)%每只蚂蚁每⼀步选择的城市

newpheromone=newpheromones(m,antcity,pop,pheromone)%更新信息素

函数initialization：

function[pop,pheromone]=initialization(m)

pop=[inf,3,1,2;3,inf,5,4;1,5,inf,2;2,4,2,inf];

newpop=pop;

f=ones(1,5);

c=0;

n=2;

i=1;

whilen<5

[min_newpop,index]=min(newpop,[],2);

j=index(i);

c=c+min_newpop(i);

f(n)=j;

newpop(i,:)=inf;

newpop(:,i)=inf;

i=j;

n=n+1;

end

c=c+pop(i,1);

pheromone=m/c;

pheromone=ones(4,4)*pheromone;

函数firstcity：

functionantfirstcity=firstcity(m)

city=['A','B','C','D'];

antfirstcity=char(zeros(1,m));

fori=1:m

ran=rand();

ifran<0.25

antfirstcity(i)=city(1);

elifran<0.5

antfirstcity(i)=city(2);

elifran<0.75

antfirstcity(i)=city(3);

el

antfirstcity(i)=city(4);

end

end

函数lectcity：

functionantcity=lectcity(pop,m,pheromone,antfirstcity)

antcity=char(zeros(m,5));

antcity(:,1)=antfirstcity;

antcity(:,5)=antfirstcity;

fori=1:m

city=['A','B','C','D'];

newcity=city;

forj=2:4

forn=1:6-j

ifnewcity(n)==antfirstcity(i)

newcity(n)=[];

break

end

end

x=antfirstcity(i)-'A'+1;

y(1:5-j)=newcity(1:5-j)-'A'+1;

p1=zeros(1,5-j);

forv=1:5-j

p1(v)=pheromone(x,y(v))*(1/pop(x,y(v)))^2;

end

p=p1/sum(p1);

q=rand();

ifj==2

ifq

antcity(i,2)=newcity(1);

antfirstcity(i)=newcity(1);

elifq

antcity(i,2)=newcity(2);

antfirstcity(i)=newcity(2);

el

antcity(i,2)=newcity(3);

antfirstcity(i)=newcity(3);

end

elifj==3

ifq

antcity(i,3)=newcity(1);

antfirstcity(i)=newcity(1);

el

antcity(i,3)=newcity(2);

antfirstcity(i)=newcity(2);

end

el

antcity(i,4)=newcity(1);

antfirstcity(i)=newcity(1);

end

end

end

函数newpheromones：

functionnewpheromone=newpheromones(m,antcity,pop,pheromone)

num=zeros(m,5);

num(:)=antcity(:)-'A'+1;

c=zeros(m,1);

forr=1:m

fort=1:4

c(r)=c(r)+pop(num(r,t),num(r,t+1));

end

end

formm=1:4

fornn=1:4

sumnum=0;

fori=1:m

forj=1:4

ifnum(i,j)==mm

ifnum(i,j+1)-num(i,j)==nn-mm;

sumnum=sumnum+1/c(i);

end

end

end

end

newpheromone(mm,nn)=0.5*pheromone(mm,nn)+sumnum;

end

end