[Scip] Non-binding inequalities

[Gerald Gamrath]

Hi Stefan,

what do you mean with "non-binding" and what do you mean with "allow to
ignore"?

SCIP does a presolving phase before the actual solving process and will
remove some redundant constraints there. However, already doing a
pairwise comparison of constraints is quite expensive, so SCIP will not
detect if a constraint is implicitly fullfilled due to two or more other
constraints. However, all constraints lead to tightening of variable
bounds and those are of course also taken into account when computing
activity bounds while looking for redundant constraints. Moreover,
constraints which are parallel to the objective function are removed
from the problem and added as a cutoff or lower bound.

There is a lot more, if you tell us what exactly you mean are looking
for, we can tell you whether this is automatically done or if you can
turn it on with a parameter.

Best,
Gerald

On 05.02.2014 13:43, Stefan Lörwald wrote:
> Hi,
>
> I'd like to know if there is an option to ignore non-binding
> inequalities provided with "SCIPcreateConsLinear" /
> "SCIPincludeConshdlrLinear(scip)". That is, does SCIP allow to ignore
> inequalities that are provably non-binding because of the objective
> function? Is it perhaps enabled by default?
>
> yours,
> Stefan
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