要求解该问题，利用如下程序求解，但只有一个0-1变量能满足要求得到0或者1，其余0-1变量始终是0，麻烦各位大神看一下是什么问题。程序如下：
Sets
i state /1,2/;
Parameters
u(i) price in state i in cases
/ 1 28
2 40/
d(i) demand at time i in cases
/ 1 80
2 90/;
Variables
p1(i) procurement quantities in cases
p2(i) procurement quantities in cases
p3(i) procurement quantities in cases
s1(i) 0or1
s2(i) 0or1
s3(i) 0or1
z total cost
q(i) procurement from maket;
Positive Variable p1(i);
Positive Variable p2(i);
Positive Variable p3(i);
Positive Variable q(i);
binary Variable s1(i);
binary Variable s2(i);
binary Variable s3(i);
s1.l(i)=1;
s2.l(i)=3;
s3.l(i)=3;
Equations
cost define objective function
demand(i) satisfy demand at time i
constraint1(i) satisfy 0 or 1
constraint2(i) satisfy 0 or 1
constraint3(i) satisfy 0 or 1
constraint4(i) satisfy 0 or 1
constraint5(i) satisfy 0 or 1
constraint6(i) satisfy 0 or 1;
cost .. z=e=sum(i,32*s1(i)*p1(i)+37*s2(i)*p2(i)+45*s3(i)*p3(i)+u(i)*q(i));
demand(i).. s1(i)*p1(i)+s2(i)*p2(i)+s3(i)*p3(i)+q(i)=e=d(i);
constraint1(i).. 15*s1(i)=l=p1(i);
constraint2(i).. 35*s1(i)=g=p1(i);
constraint3(i).. 10*s2(i)=l=p2(i);
constraint4(i).. 25*s2(i)=g=p2(i);
constraint5(i).. 15*s3(i)=l=p3(i);
constraint6(i).. 30*s3(i)=g=p3(i);
option minlp=**b;
Model tr /all/;
Solve tr using minlp minimizing z;
Display s1.l,s2.l,s3.l,p1.l,p2.l,p3.l,q.l;
结果如下：