[Cbc] Restricting computation time for infeasible problems

[John Forrest]

Christopher,

The maximum time can easily be set - setMaximumSeconds.

Infeasible problems often take much longer.  If you want to send me some 
data, I can have a quick look to see if there is something simple that 
can be done.

John Forrest
On 06/10/15 15:44, Christopher Gross wrote:
> Hi,
>
> I am using CMPL with CBC as a backend in a software that is used without me
> being present. The users are able to enter data into the software which will
> then generate a data file and solve the model I created. Currently, the
> software is in the testing stage so users expect timely feedback. I have
> therefore limited the solution time to 120 seconds which gives quite good
> solutions so far.
>
> Sometimes, users enter data that leads to infeasibilities in the model.
> Often, this results in a quick failure (within a few seconds) with an error
> message. Sometimes, however, it might take very long for CBC to fail. In the
> most recent instance of this problem it took the solver more than 20 minutes
> of processing at which point the users called me and asked me to kill the
> process so they could try again with different data.
>
> Obviously, it is undesirable to have CBC processing for such a long time.
> Ideally, I would like to always terminate after 120 seconds and then give
> the user the intermediate result, whether a solution has been found or not.
>
> Why is CBC sometimes taking so long when presented with an infeasible
> problem? And what can I do to limit this time?
>
> Thanks and best regards,
>
> Christopher
> --
> Christopher Gross, M.Sc.
>
> Lehrstuhl für Health Care Operations/Health Information Management
>
> Universitäres Zentrum für Gesundheitswissenschaften am Klinikum Augsburg -
> UNIKA-T, Neusässer Straße 47, 86156 Augsburg
>
> Wirtschaftswissenschaftliche Fakultät, Universität Augsburg,
> Universitätsstraße 16, 86159 Augsburg
>
> Tel.: +49 821 598-6454
> E-Mail: christopher.gross at unikat.uni-augsburg.de
> Web: http://www.wiwi.uni-augsburg.de/bwl/brunner/
>
>
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