[SCIP] "meta heuristic" question

[Jakob Witzig]

Hi James,

you could set the check-flag of your symmetry breaking constraints to 
FALSE. Non-check constraints will not be checked to verify whether a 
solution (obtained by some heuristic) is feasible or not.

I don't understand how an LP solution can be integer but infeasible 
maybe I miss something. Do you mean infeasible wrt to your symmetry 
breaking constraints? This should not happen when you mark these 
constraint to be initial or separate.

Cheers,
Jakob

Am 15.08.2016 um 12:06 schrieb James Cussens:
> Dear SCIPers,
>
> I would like to write a primal heuristic which does the following. If
> any other heuristic proposes what turns out to be an infeasible
> solution, it takes that infeasible solution as input and generates a
> different (hopefully) feasible one. Ideally the same process would be
> invoked if the LP relaxation was integer (but infeasible).
>
> The rationale is as follows. I have added "symmetry breaking"
> constraints to my problem so that only one distinguished representative
> of a (possibly large) class of 'equivalent' solutions remains feasible.
> If a heuristic proposes one of these now infeasible equivalent solutions
> I want my "meta" heuristic to propose the distinguished representative.
>
> Is there a "nice" way to do this?
>
> James
>
> --
> James Cussens
> Dept of Computer Science &
> York Centre for Complex Systems Analysis
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>
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-- 
Jakob Witzig

Zuse Institute Berlin (ZIB)

Division Mathematical Optimization and Scientific Information
Research Group Mathematical Optimization Methods

Takustrasse 7
14195 Berlin

Tel. : +49 (0)30 84185-416
Fax  : +49 (0)30 84185-269
email: witzig at zib.de