Hi there,

I’m trying to use dual variables, but it appears not to work when there are 2 variables in one constraint.

Is there an option to make this work?

I’m trying to solve the following and want a dual variable for both x and y. If I try only one dual variable for the s variable, it does work.

```
variable x(m,1) nonnegative;
variable y(m,3) nonnegative;
variable s(n,3) nonnegative;
dual variables D1{3} D2{3};
minimize (sum(c'*x) + sum(-q.*(pb(1)*(y(:,1)) + ...
pb(2)*(y(:,2)) + pb(3)*(y(:,3)))) );
subject to
for z = 1:3
y(:,z) <= x : D1{z} D2{z};
s(:,z) <= s_max';
for i = 1:n
I(i,:)*y(:,z) == ksi(i,z) - p(i) + s(i,z);
end
end
```

If someone can help me that would be great!