这样改后可以运行，但是无可行解，模型需改进？sets:
gol/1..4/:gdp,k,l,e,so,cod,gdg,soo,cdd,z,theta;
endsets
data:
gdp=2 3 4 5;
l=5 6 8 9;
k=55 56 57 58;
e=12 13 14 15;
so=7 8 9 10;
cod=11 12 13 14;
enddata
min=@sum(gol:theta);
@for(gol(i):
theta(i)=0.5*gdp(i)/(gdp(i)+gdg(i))+0.25*so(i)/(so(i)+soo(i))+0.25*cod(i)/(cod(i)+cdd(i));
@sum(gol(j):z(j)*l(j))<=l(i);
@sum(gol(j):z(j)*k(j))<=k(i);
@sum(gol(j):z(j)*e(j))<=e(i);
@sum(gol(j):z(j)*gdp(j))-gdg(i)=gdp(i);
@sum(gol(j):z(j)*so(j))-soo(i)=so(i);
@sum(gol(j):z(j)*cod(j))-cdd(i)=cod(i););


总感觉楼主程序编写得不太直观，规范。愚见，笑纳！