Error for constraint of sets

GAMS
1

Dear All,

I have a problem to write syntax of this simple formula “n not equal m” in equation section. This n, m are sets with n = {1,2,3} and m = {1,2,3,4}. I try to solve this problem by using this syntax to represent that n is not equal to m

notequalm(m) … m - n =g= abs(1);

However, I get these error warnings :

108 notequalm(m) … m - n =g= abs(1);
**** $148 $148,653

148 Dimension different - The symbol is referenced with more/less
indices as declared
257 Solve statement not checked because of previous errors
653 The left side of an equation cannot be a set expression

How to solve this problem? Thank you for the asnwers.

2

Hi Urise

This is not correct for several reasons and it is not clear to me what you want to achieve.
Even if you would model it like this:

set m /14/,
n(m) /13/;

notequalm(m,n) … ord(m) - ord(n) =g= 1;

nothing happens in the rest of your model.

If you would have another equation

eq1(m)…
a(m) + b(m) =G= 10;

this equation would still be there for every m and not for every m > n.

Cheers
Renger

3

Hi Renger,

Actually I want to limit my objective function in which the index “m” and “p” should not be equal to “n”.

How to do this in GAMS syntax? I try it in equation section but those errors happened.

4

Show your objektive function…