GAMS World Forum

Hi Steve Many thanks for your reply, it was very useful. I used the suggestion to implement MPEC. I'm not sure if it would work as bilevel, as the model is quite large... I tried the Harker model and it wouldn't work. But the MPEC does work! Here is the code. April8.gms For 2019, the solution does n...

Hi peeps So i want to programme a Stackelberg model with the following complementary conditions: image.png It is a non-linear maximisation problem so I thought I should use 'nlp' to solve the model. Whilst the nlp programme runs without an error, it does not seem to have taken into account the compl...

Hi achristensen thanks so much for your reply, it was very helpful. I initially tried mu("Russia") since this seemed like the most straightforward approach and it got rid of the error messages. But it didn't work with the model statement i think because my dimensions were still a bit messe...

i am having trouble writing out the following KKT condition Screenshot 2022-04-06 at 15.48.03.png If i type the following code in it works (provisionally) fine: Screenshot 2022-04-06 at 15.54.03.png but ideally, i would not like to have a separate variable mu_Russia. I would like to define mu over t...

Every player has a set of mines and one dual variable for supply. Therefore i don't think i can simply write
Rus_KKT_2(Rus_mines, players1)

since this would create equilbirum conditions that relate russia mines to US and Australian dual variables which wouldn't make much sense.

Hi i am struggling with writing out the KKT conditions for my model This is what i want I'm trying to write Screenshot 2022-04-04 at 01.21.17.png my best attempt is the following: Rus_KKT_2(Rus_mines).. s_coefs(Rus_mines,"alpha")+ lambda(Rus_mines)-xi(Russia) =g= 0; Which gives these error...

Thank you so much. That is very helpful. I would never have thought of doing it that way.

Hi I am modelling international coal markets. I want to see how my model changes when i change demand a bit. I currently have the slope and intercept data fro my demand curves (South Asia, Americas, Europe and China all get their own demand curves). Then i want to re run the programme with slightly ...

yes that works very well- thanks

Hi!
yes that works a treat. ill know to check the .lst next time. thanks a lot