目标（The objective）最少费用：
3
4
Min z 5x
i 1
j 124
cijxi
31
j
6x 8x
11
2x
12
6x
13
7x
14
4x
21
9x
22
32
23
3x 8x
x33 5x
34
约束条件：
供应限制（The supply constrains） 指标约束（The damand constrains）
x11 x12
x21 x22 x x
32 31
LINGO模型： model: sets: origin/1..3/:a; sale/1..4/:b;
x11
x13 x14 30
x12
x23 x24 25
x12
x33 x34 21
x 14
x21 x31 15 x22 x32 17 x23 x33 22 x24 x34 12
routes(origin,sale):c,x; endsets data: a=30,25,21; b=15,17,22,12; c=6,2,6,7,4,9,5,3,8,8,1,5; enddata
[OBJ]min=@sum(routes:c*x); @for(origin(i):[SUP]