Hi Renger,

Thank you for the heads-up. I will rephrase my question here.

Basically, I have a set i, which has 48 elements. And I would like to define 48 equality constraints for each elements in my set i.

What I want to achieve is, for each i = 1:48, i have x(i)+y(i) =e= a(i) - b(i).

I expressed this as equ(i)… x(i)+y(i) =e= a(i) - b(i) ;

In this equation, x and y are decision variables (both have 48 numbers of variables); a and b are defined parameter.

Since GAMS does not recognize “i” as the index number, how can I represent those equation? I hope there will be other solutions, other than simply putting 48 equations there.

Thanks very much.

Regards,

Tian

On Tuesday, March 31, 2015 at 4:04:12 PM UTC+8, Renger van Nieuwkoop wrote:

Hi Tian

You have an error â€œuncontrolled set entered as constantâ€, but it is hard to see where this error originates, as you do not provide enough information (read the Guidelines to this forum).

Cheers

Renger

From: gams...@googlegroups.com [mailto:gams...@googlegroups.com] On Behalf Of Tian Zhang

Sent: Dienstag, 31. MÃ¤rz 2015 05:17

To: gams...@googlegroups.com

Subject: How to define equality constraints? “Uncontrolled set entered as constant”

Dear all,

Very honored to join this helpful group.

May I ask how to define equality constraints on a certain set?

I wrote:

equ(i)… x(i)+y(i) =e= a(i) - b(i) ;

In this equation, I want express that for the set i, I have i equality constraints. x and y are decision variables; a and b are parameter, whose values are known.

But I got this error:“Uncontrolled set entered as constant”. I learnt that i cannot be used as the index number, yet still cannot figure out how to fix this.

Hope to hear from you soon. Thank you very much.

Cheers.

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