GAMS World Forum

Hi, I'm working on a Closed Loop Supply Chain Network model, and it worked with me. But I have a small issue, when I'm making a specific parameter (Vp) with values. The model says no optimal solution, but when I make the same parameter with zero value. The model is solved and gives me an optimal sol...

Hi All, I'm working on a replication of a mathematical model, and I have a question related to the below constraints. I don't how to write it on GAMS. Especially for the number 2 over the PROD sign. Would someone help me? And forgive me if the question is too naive as I'm still new to GAMS. Screensh...

Dear All, Kindly I need your urgent support to find what's wrong in my model. I wrote the below model, but it's still infeasible. When I'm changing some numbers in the model, the number of equations in conflict reduce as shown in the below photos. image.png image.png But it still infeasible, and I d...

Dear All,

I created a GAMS model, and it worked with me but with the feasopt CPLEX option and gave me the below result. Currently, I'm working on reducing the GAP. How should I do that?
Thanks in advance for your support

I added it in the first post, but kindly find it attached

Thanks for your support

Dear All,

I'll appreciate any guidance on the above topic.

Best Regards
Omar

Dear All, I wrote the attached model below, but I got an infeasible integer solution and am working on debugging the model. Thesis Model Replication.gms In the pre-solve stage, I got the below error. image.png So, I thought I was missing indicating in the constraint that (j, i)∈A_j^- and j ∈ S. My q...

Dear Atharv, Thanks a lot for your suggestion I used the big M method as you told me, would you please confirm to me if I'm writing it correctly? < Scaler bigM /1000/; Binary Variable y(i,j) v(i); Equations VBinC1 "1, if node i is used" VBinC2 "0, Otherwise" ; VBinC1(i,j).. x(i,j...

Dear All,

Kindly I would like to know how to write the below conditional statement in GAMS Is just make yij and vi binary variables?

Thanks in advance

Dear Atharv,

Thanks a lot for your explanation

But my question was how to write the expression Sum h ϵ H(l,p). For example, am I writing it correctly in the below code?
<C1(l,p,t).. sum(h$HLP(l,p),ALPHA(h,l,p,t)*MAKE(h,p,t)) =l= U(l,p,t) ;>
Thanks in advance