hello

I have this situation in GAMS:

1 sets

2

3 i A B C quarries /1*3/*

4 j number of factory /14/ ;

5

6 parameters

7

8 amount(j) the amount of iron that can be processed in a day in factory

9 /

10 1 40

11 2 60

12 3 20

13 4 80

14 /

15

16 w(i) daily amount of iron obtained from the quarries

17 /

18 1 100

19 2 40

20 3 60

21 / ;

22

23 table c(i,j) cost of transportation

24

25 1 2 3 4

26 1 7 8 7 12

27 2 8 7 9 13

28 3 10 6 7 12

29 ;

30

31 variable

32 z

33 x(i,j);

34

35 Positive variable

36 x;

37

38 Equations

39 Obj

40 Cons1(j)

41 Cons2(i);

42

43 Obj… z=e=sum((i,j), c(i,j)*x(i,j));

44 Cons1(j)… sum(i, x(i,j)) =e= w(i);

**** $149

**** 149 Uncontrolled set entered as constant

45 Cons2(i)… sum(j, x(i,j)) =e= amount(j);

**** $149

**** 149 Uncontrolled set entered as constant

I searched,but I did not find solution. How can I fix it? and Can you fix it?

Looking at the constraint where you get the error.

Cons1(j)… sum(i, x(i,j)) =e= w(i);

The constraint is defined over j so j is known. The summation is defined over i so i is known **(only on the left hand side)**. On the right hand side, GAMS does not know what is i and therefore, you get the error.

You have to check your constraint again. Both of the following are correct in terms of syntax

- cons1(j)… sum(i, x(i,j)) =e=
**w(j)**;
- cons1(
**i**)… sum(**j**, x(i,j)) =e= w(i);

Hope it is clear now.

But w(j) is not defineted

This is precisely why I told you to rethink your constraint. The way you have written the constraint does not make sense. What is w(i) in connection with that constraint? The constraint does not know i.

This is why I gave you two examples of what is acceptable.

Cons1(j)… sum(i, x(i,j)) =e= w(i);

Think about this in general terms. Do you want to write this constraint for each i or for each j?

To me, it looks like you want summation of certain things to be equal to w(i) in this case you should write your constraint for i by doing cons1(i).

But if you do just that, you will get an error for x(i, j) saying j is not under control.

Please understand your constraint first and then write it in GAMS.