GAMS World Forum

Hi Manassaldi, i tried to execute the BigM-Relaxation approach of my model. However my computer was out of memory. The workspace was more than 27.000 Mb and then GAMS stopped with the message "Out of memory". I think by memory GAMS is referring to RAM and not to harddrive. Because on my ha...

Hi Manassaldi, So, if this upper bound is equal to 50 you have to insert 50 equation for x and 50 for y. I don't really have an upper bound. The only upper bound I have is the number of timeslots,which is 1440. So I have to insert 1440 *2= 2880 equations when using the first approximation? What abou...

Hi Manassaldi, Thank you for your answers I still have questions: 1) In your first formulation I think you have to insert equations for all timeslots and the number of time in which x is has to be know in advance. Is that correct? eqfirstx(t).. 1 - x(t) + sum(tp$(ord(tp) lt ord(t)),x(tp)) + xfirst(t...

Thanks Manassaldi for your answer, but I do nor understand your code: set t /1*1440/ ; alias(t,tp,tpp); binary variable x(t) y(t) ; variable z ; equation eq1,eq2,eq3,eq4,eq5,eq6,eqobj ; eq1(t,tp).. sum(tpp$(ord(tpp) le ord(t)),x(tpp)) =l= ord(tp) + (1-xpos(tp,t))*1440; eq2(t,tp).. sum(tpp$(ord(tpp) ...

Thanks Manassaldi for your answer (and your general great effort :) ), I have to admit that I do not really understand the things you said. What is meant by: I think you must to propose the maximum time in which x(t) = 1 and y(t) =1 before, but you have to modifies some restriction. As I said in the...

Thanks once again Manassaldi for your good answer, Now I understood how your concept works. You said that I'll have to do this for every occurence of x(t)=1 and y(t)=1 I have to comments/questions regarding this: 1) The number of timeslots, inwhich x(t) = 1and y(t) =1 is not known in advance and has...

Hi Manassaldi, thank you for your answer. Unfortunately I'm having a hard time understading what you posted. Even the first equation is not understandable for me (I have not tried to understand the other equations yet, because I am struggeling even with the first one): eqfirstx(t).. 1 - x(t) + sum(t...

Hi guys, the problem I am facing is going to be difficult to explain and I strongly question whether something like this is solvable with GAMS. But I'll try: Lets say we have two binary decision variables x(t) and y(t) and lets assume they have the following values: t: 0 1 2 3 4 x: 0 0 1 0 1 y: 1 0 ...

Hi Manassaldi,

it seems to work How did you derive those equations? Also with the basic steps?

Thanks a lot for your great help!

Thanks again for the answers. Where can I read more about those basic steps? I typed it into google but somehow I could not find useful information about them.