GAMS World Forum

Hi Setha, You need to use set-indices in your equationnames too. For example: c1(i).. <equation> And in your objective funtion the left-handside doesn't have index i, but the righhand-side does. Perhaps you want to sum over i in your righthand-side? See also: https://www.gams.com/35/docs/UG_Equation...

Hi RZoro95, In your GDXXRW-call you are refering to a parameter "x": execute "gdxxrw PortfolioComp.gdx o=PorioComp.xls par =x rng=foglio1!a1 cdim=1 rdim=1 " However, in your model "x" is declared a a variable, hence the error. To solve this, change par to var: execute &...

Hi Rzoro95, Two options I can think of: 1) make a new sheet and add the data of all the sheets into one two-dimensional table. Then you only need to read-in one table. 2) read in data per sheet into seperate parameters (e.g. parameters foglio1(i) ... foglio8(i)) and add them together in GAMS in a tw...

Hi Lucky,

Try: Output: Regards,
GFA

Hi lcarreon,

How do you know your problem could be solved with LP? I see a square in your objective function meaning it is not a linear function.
And I think we are missing some information about the problem. What is subscript t and b?

Cheers,
GFA

Dear Rodrigue, That is because not all "af"-"Ag" combinations have data. For example: "AV" and "Resext" (elements of "af") only have data with the element "Bcen2" in SAM-parameter, but "Bcen2" is not in "Ag" subset so it...

Hi hein,

Have a look here and especially at example 4: https://www.gams.com/latest/docs/UG_GDX.html
You might want to use something like: "$load setNo1<Parameter2.dim1" etc. to load the setelements from GDX.

Regards,
GFA

Hi,

One way would be to write it like this: Cheers,
GFA

Hi sandrina,

Try using starting values for your variables, this usually helps the solve. See: https://www.gams.com/latest/docs/UG_Variables.html
Hope this helps.

GFA

Hi Sandrina,

It is hard to give any advice since the information you provided is quite limited.
One thing you could try is to make your model as small as possible, or make a simple toy example. This usually makes it easier to analyse the model's behaviour.

Regards,
GFA