duomubiao.m

出自一本书中的解决多目标优化问题的MATLAB代码

function f1=f(x)
f1=x(:,1).*x(:,1)/4+x(:,2).*x(:,2)/4;
function f2=f(x)
f2=x(:,1).*(1-x(:,2))+10;
NIND=100;
MAXGEN=50;
NVAR=2;
PRECI=20;
GGAP=0.9;
trace1=[];trace2=[];trace3=[];
fieldD=[rep([PRECI],[1,NVAR]);[1,1;4,2];rep([1;0;1;1],[1,NVAR])];
Chrom=crtbp(NIND,NVAR*PRECI);
v=bs2rv(Chrom,fieldD);
gen=1;
while gen<MAXGEN,
    [NIND,N]=size(Chrom);
    M=fix(NIND/2);
    ObjV1=f1(v(1:M,:));
    FitnV1=ranking(ObjV1);
    Selch1=select('sus',Chrom(1:M,:),FitnV1,GGAP);
    ObjV2=f2(v(M+1:NIND,:));
    FitV2=ranking(ObjV2);
    Selch2=select('sus',Chrom((M+1):NIND,:),FitnV2,GGAP);
    Selch=[Selch1;Selch2];
    Selch=recombin('xovsp',Selch,0.7);
    Chrom=mut(Selch);
    v=bs2rv(Chrom,fieldD);
    trace1(gen,1)=min(fi(v));
    trace1(gen,2)=sum(f1(v))/length(f1(v));
    trace2(gen,1)=min(f2(v));
    trace2(gen,2)=sum(f2(v))/length(f2(v));
    trace3(gen,1)=min(f1(v)+f2(v));
    trace3(gen,2)=sum(f1(v)/length(f1(v))+sum(f2(v))/length(f2(v)));
    gen=gen+1;
end
figure(1);clf;
plot(trace1(:,1));hold on;plot(trace1(:,2),'-.');
plot(trace1(:,1),'.');plot(trace1(:,2),'.');grid;
legend('解的变化','种群均值的变化')
xlabel('迭代次数');ylabel('目标函数值');
figure(2);clf;
plot(trace2(:,1));hold on;
plot(trace2(:,2),'-.');
plot(trace2(:,1),'.');
plot(trace2(:,2),'.');grid;
legend('解的变化','种群均值的变化')
xlabel('迭代次数');ylabel('目标函数值');
figure(3);clf;
plot(trace3(:,1));hold on;
plot(trace3(:,2),'-.');
plot(trace3(:,1),'.');
plot(trace3(:,2),'.');grid;
legend('解的变化','种群均值的变化')
xlabel('迭代次数');ylabel('目标函数值');
figure(4);clf;plot(f1(v));hold on;
plot(f2(v),'r-.');grid;