[Cbc] Cbc returns infeasible, Gurobi works

[Alexander Timmermeister]

Hi,

thank you all for your help. I completely missed the “< or <=” issue. Having changed that I still get infeasible with 2.8 and feasible with the standalone 2.9 just like John said. I will go on and update to 2.9 in my tool then as well.

Best regards,
Alexander

Von: Babak Moazzez [mailto:bmoazzez at ucdavis.edu]
Gesendet: Montag, 23. März 2015 05:15
An: Alexander Timmermeister
Betreff: Re: [Cbc] Cbc returns infeasible, Gurobi works

I solved with gurobi, I got optimal solution with z = 1487170.887452
Cbc 2.9.2 gives error because of the > and < constraints. When I changed them to >= and <= respectively, Cbc gives optimal solution with  z = 1487170.88745200
Babak

On Thu, Mar 19, 2015 at 7:11 AM, Alexander Timmermeister <Alexander.Timmermeister at locom.de<mailto:Alexander.Timmermeister at locom.de>> wrote:
Hi all,

I have a MIP for which cbc returns infeasible for no obvious reason (I am quite certain that there is a feasible solution). I used cbc 2.8.13.

I tried to solve it using Gurobi 6.0.2 and it returned a solution of value 1487126.75.

Can anyone help me with this?

I attached a file which should be in standard *.lp-file format.

Thanks in Advance,
Alexander Timmermeister


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--
Babak Moazzez
Post Doctoral Scholar
University of California Davis

Email: bmoazzez at ucdavis.edu<mailto:bmoazzez at ucdavis.edu>
Tel: (530) 752 5076
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