求Lingo高手帮忙混合整数规划,设施规划问题求解!对于建立函数和用lingo建模都不太会,求教!4个生产厂a,b,c,d,每个厂可选择生产0,10或20单位 .不同规模的固定成本矩阵 a b c d10 单位 600 550 560 610 20单位 1000 920 930 10204个需方,A,B,C,D,需求分别是11,18,12,10.运费矩阵 a b c dA 11 12 13 14B 15 16 17 18C 19 20 21 22D 23 24 25 26求总费用最小.有建设固定费用就不知道该如何建模了……求高手解答!

model:
sets:
supply/1..4/;
demand/1..4/:d;
production/1..3/:a;
link1(supply,demand):cost1,x;
link2(production,supply):cost2,y;
endsets
data:
a=0 10 20;
d=11 18 12 10;
cost1=
11 12 13 14
15 16 17 18
19 20 21 22
23 24 25 26;
cost2=
0 0 0 0
600 550 560 610
1000 920 930 1020;
enddata
min=@sum(link1:cost1*x)+@sum(link2:cost2*y);
@for(demand(j):@sum(supply(i):x(i,j))=d(j));
@for(supply(i):@sum(production(k):y(k,i)*a(k))>=@sum(demand(j):x(i,j)));
@for(supply(i):@sum(production(k):y(k,i))=1);
@for(link2:@bin(y));
end