[SCIP] Looking for example how to express symmetry groups

[Johann-Tobias Schäg]

Thank you for butting in. I did not know about this format. I reply to the mailing list because others might find it useful too.

> João Dionísio <joao.goncalves.dionisio at gmail.com> hat am 13.06.2025 10:02 CEST geschrieben:
>  
>  
> Dear Johann-Tobias,
>  
> Just butting in to say that if what you want is something similar to the dec file format https://gcg.or.rwth-aachen.de/doc-3.5.0/own-dec-file.html, which informs SCIP/GCG about available decompositions, then such a format does not exist for symmetries. As far as I'm aware, that is the case in SCIP and everywhere else. I'm not a symmetry person, so I'm not sure how difficult it would be to implement it, or if it would be useful.
>  
> Hopefully, this answers the originalhttp://OR.SE question.
>  
> Best,
> João Dionísio
> 
> On Thu, Jun 12, 2025 at 11:12 AM Johann-Tobias Schäg <johann-tobias at schäg.de mailto:johann-tobias at sch%C3%A4g.de> wrote:
> 
> > I am aware that there are mutliple ways to handle symmetries in SCIP
> >  
> > https://www.scipopt.org/doc/html/cons__orbisack_8h.php
> > https://www.scipopt.org/doc/html/cons__orbitope_8h.php
> > https://www.scipopt.org/doc/html/cons__symresack_8h.php
> >  
> > All those are for binary variables.
> >  
> > I occasionally encounter 0-1 ILP which have symmetries so large that SCIP fails to (fully) detect them. I asked on the OR stack exchange whether there is a standardized format for symmetry groups: https://or.stackexchange.com/questions/13187/are-there-existing-formats-to-express-symmetries-between-variables-in-milp?noredirect=1#comment28418_13187 and was pointed towards SCIP being potentially interesting for that.
> >  
> > Is there some examples which use those constraints handlers?
> > The documentation i linked above is to dense for me to make sense of.
> >  
> > Sincerely,
> > Johann-Tobias Schäg
> >  
> >  
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