[Scip] How good are SCIP solutions?

[Stefan Vigerske]

Hi,

as long as solutions are feasible, the one with the smaller objective 
value are better.

The points provided in MINLPLib should all be feasible. For easy and 
medium difficult instances, they correspond to an optimal solution. For 
difficult ones, they should correspond at least to a good feasible one.

Solutions you get from SCIP are usually feasible w.r.t. tolerances. In 
the case of MINLP, we sometimes observed violations of nonlinear 
constraints that are slightly above SCIP's feasiblity tolerance. We are 
working on fixing this problem.

Since we have run SCIP also on MINLPLib instances and submitted 
improving solutions to this library, it should be hard to find solutions 
for MINLPLib instances with SCIP that have a smaller objective value 
than the one given at the library.

Best,
Stefan

On 11/24/2012 02:39 PM, Liffey1986 at gmx.de wrote:
> Dear All,
>
> I'm using SCIP to solve MINLPs. I tried to solve some instances from libraries such as the MINLPLib.
> In these libraries the best solutions are usually given. But how do I know which solution is the better one, the given solution or the solution I got from solving the instance with SCIP? Suppose I have a minimization problem, can I then always assume that the smaller objective value is the better one?
>
> Regards,
> Ina
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