[size=14.399999618530273px]以四种货币作为投资对象，命令写为：（0.970877，0.970911，0.970811的来源见下图，就是直接标价法相除）

[size=14.399999618530273px]sets:

[size=14.399999618530273px]currency/1..4/:r,x;

[size=14.399999618530273px]stst(currency,currency):cov;

[size=14.399999618530273px]

[size=14.399999618530273px]endsets

[size=14.399999618530273px]

[size=14.399999618530273px]data:

[size=14.399999618530273px]r=0.0377090.003560 0.034163 0.050586;

[size=14.399999618530273px]cov=3.3555600.056175 0.743041 1.197362  

[size=14.399999618530273px]        0.056175 0.115442 0.156123 0.035431

[size=14.399999618530273px]        0.743041 0.156123 0.787501 0.380643

[size=14.399999618530273px]        1.197362 0.035431 0.380643 0.703761;

[size=14.399999618530273px] rp=?;

enddata

[obj]min=@sum(stst(i,j):x(i)*x(j)*cov(i,j));

[one]@sum(currency:x)=1;

[two]rp>=@sum(currency:x1*(1*(1+r1)-1)+x2*(0.970877*(1+r2)-1)+x3*(0.970911*(1+r3)-1)+x4*(0.970811*(1+r4)-1));

end

为什么每次输入不同的RP，结果却是一样的？？