Resolving GAMS Error for the Display Command

GAMS
,
1

Hello
I wrote the following code in GAMS but encountered an error. In the code,
I want to subtract several specific values of Y from X. E is a table with 5 columns and 24 rows. H is a parameter that includes 33 values, each with its own specific value (for example: Parameters H /1 20, 2 30, ..., 33 40/). The error I am facing is displayed for the display command, and its text is as follows:

Error 141: Symbol declared but no values have been assigned. Check for missing data definition, assignment, data loading or implicit assignment via a solve statement. A wild shot: You may have spurious commas in the explanatory text of a declaration. Check symbol reference list.

This error is displayed even though each of the parameters E and H have numerical values. I would appreciate your guidance.

Code:

Parameters X(i, j), Y(k);
Equation es1, es2, es3, es4, es5, es6;
X(i, j) = E(i, j);
es1(k)..    Y(k) =e= H(k);
es2(i, j, k)..  Y('6') =e= X(i, 'j1')-Y('6');
es3(i, j, k)..  Y('18') =e= X(i, 'j2')-Y('18');
es4(i, j, k)..  Y('21') =e= X(i, 'j3')-Y('21');
es5(i, j, k)..  Y('24') =e= X(i, 'j4')-Y('24');
es6(i, j, k)..  Y('30') =e= X(i, 'j5')-Y('30');

display Y;
2

Hi @halfa ,

Equations should be used to define constraints that go into a model.

If an equation does not contain any variables (as in this case), it should not be an equation but just an assignment statement.

Apart from that, I do not see how those equations e2 to e6 should make sense as the only way to fulfill them would be that all occurring X and Y are zero.

I hope this helps!

3

Thank you @Fred_Fiand for your response. I am not very proficient in GAMS. Do you mean that I should edit the code as follows?

Y(k) = H(k);
Y('6') = X(i, 'j1')-Y('6');
Y('18') = X(i, 'j2')-Y('18');
Y('21') = X(i, 'j3')-Y('21');
Y('24') = X(i, 'j4')-Y('24');
Y('30') = X(i, 'j5')-Y('30');