model:
sets:
year/1..3/;
project/1..5/;
endsets
data:
e = 700,900,1200;
U1 = 300,400,450;
U2 = 300,350,350;
b = 700,500,800,400,680;
g = 0.05;
f = 0.055;
r = 0.2;
endsets
var x(year,project)>=0;
max=@sum(year(i):@sum(project(j):x(i,j)));
@for(year(i):@sum(project(j):x(i,j))<=e(i)+@sum(year(k)|k<=i:U1(k)*(1+g)^(i-k))+@sum(year(k)|k<=i:U2(k)*(1+f)^(i-k))-@sum(year(k)|k<i: @sum(project(j):x(k,j))*(1+r)^(i-k)));
@for(year(i):@sum(year(k)|k<=i:U1(k)*(1+g)^(i-k))<=U1(i));
@for(year(i):@sum(year(k)|k<=i:U2(k)*(1+f)^(i-k))<=U2(i));}

有没有谁帮忙看看呢˃̣̣̥᷄⌓˂̣̣̥᷅