Search found 29 matches

by dunyayigezerken
3 years ago
Forum: Modeling
Topic: wrong solution
Replies: 3
Views: 2653

Re: wrong solution

Hello !!! I have modeled this problem and solved this on GAMS but solution I am getting is not correct. Can anyone check my code and tell me where I am wrong... $eolcom # $title MSW sim1 $offupper $onecho >inputsim1.txt set=i rng=sets!B3:B4 rDim=1 set=j rng=sets!D3:D6 rDim=1 par=price rng=SP!B3:D7 ...
by dunyayigezerken
3 years ago
Forum: Modeling
Topic: How to formulate that once binary variable equals 1 then other one equals zero forever?
Replies: 2
Views: 2149

Re: How to formulate that once binary variable equals 1 then other one equals zero forever?

if var1 and var2 are binary, you can do this by using the constraint var1 + var2=e= 1; However, you would be introducing nonlinearities/nonconvexities in your problem by such a formulation that uses obj1*var1. If var1 depends 'only' on data, it would be advisable to calculate it beforehand and use ...
by dunyayigezerken
3 years ago
Forum: Modeling
Topic: How to formulate that once binary variable equals 1 then other one equals zero forever?
Replies: 2
Views: 2149

How to formulate that once binary variable equals 1 then other one equals zero forever?

I need to choose objective function under some circumstances. obj_select = obj1*var1 + obj2*var2 . . . obj.. z =e= obj_select I need to decide var1 and var2 binary variable values. Conditions; When var1 = 1 for a condition then var2 =0 no matter it became 1 before, the model just select the obj1 to ...
by dunyayigezerken
3 years ago
Forum: Modeling
Topic: How to model dividing parameter by variable?
Replies: 1
Views: 2232

How to model dividing parameter by variable?

a(i) =e= b(i) + (parameter1 / parameter2 * var1) I tried to define this with a parameter that represent an interval what I need for example parameter interval(ch)/ 1...0.8 2...0.82 3...0.84 ........ 20...1 Then; I define a binary variable c(i,ch) which assigns each i to a ch in the interval paramet...
by dunyayigezerken
3 years ago
Forum: Solvers
Topic: Why is GAMS stucked at an elapsed time during searching for a solution?
Replies: 9
Views: 6644

Re: Why is GAMS stucked at an elapsed time during searching for a solution?

I would first try to see if you can reproduce this with the latest version. You could e.g. submit to NEOS and use the latest version there. -Michael Hello Michael, Thanks for your advise. However, I think that I solved the problem. I guess that the solver tries to prove all branches before cutoff a...
by dunyayigezerken
3 years ago
Forum: Solvers
Topic: Why is GAMS stucked at an elapsed time during searching for a solution?
Replies: 9
Views: 6644

Re: Why is GAMS stucked at an elapsed time during searching for a solution?

Yes, this seems odd. It could be that Cplex is stuck solving the node lp. You could turn on the detailed node log by setting option mipdisplay = 5. This will give you much more output (all the LP logs from the nodes) but might give you an idea what's wrong. If you are using the latest version of Cp...
by dunyayigezerken
3 years ago
Forum: Solvers
Topic: Why is GAMS stucked at an elapsed time during searching for a solution?
Replies: 9
Views: 6644

Re: Why is GAMS stucked at an elapsed time during searching for a solution?

To verify that it's not your computer, try solving it via the NEOS Optimization Server. There's an 8 hour time limit on jobs (if I recall correctly), and you can't write output files, but you can get the GDX output returned to you! When I changed a constraint, the model is running and also MATLAB e...
by dunyayigezerken
3 years ago
Forum: Solvers
Topic: Why is GAMS stucked at an elapsed time during searching for a solution?
Replies: 9
Views: 6644

Re: Why is GAMS stucked at an elapsed time during searching for a solution?

There are phases in Cplex that can take a very very long time (e.g. processing of node 0) without messages to the log. If you send more of your log, then perhaps we can answer better. -Michael Ekran Alıntısı.PNG I tried another model and the systems stucks like that on the image. Model is working b...
by dunyayigezerken
3 years ago
Forum: Solvers
Topic: Why is GAMS stucked at an elapsed time during searching for a solution?
Replies: 9
Views: 6644

Re: Why is GAMS stucked at an elapsed time during searching for a solution?

Ekran Alıntısı.PNG
I tried another model and the systems stucks like that on the image.
MOdel is working but process screen does not update. And when the resource limit exceeded the results give 3.11% gap where the model stucked.
by dunyayigezerken
3 years ago
Forum: Solvers
Topic: Why is GAMS stucked at an elapsed time during searching for a solution?
Replies: 9
Views: 6644

Why is GAMS stucked at an elapsed time during searching for a solution?

Hi, I have a MILP problem, when I started the GAMS, it stucked at elapsed time = 6518.72 sec. However, I defined ; option mip=cplex; option lp=cplex; option optcr=0; option iterlim=1000000000; option reslim=10800; The GAMS is still running, however the screen which shows active processes doesnt chan...