[Scip] One small question

Stefan Vigerske stefan at math.hu-berlin.de
Sun Jul 14 13:53:09 MEST 2013


Hi,

On 07/14/2013 11:25 AM, Rostislav Stanek wrote:
> Dear SCIP community,
> I have a small question: If I get the following output:
>
> [linear] <subtour#0>: 0 <= <x#6#1>[B] +<x#41#1>[B] +<x#41#6>[B] <= 2;
> violation: right hand side is violated by 1
> [linear] <subtour#0>: 0 <= <x#6#1>[B] +<x#41#1>[B] +<x#41#6>[B] <= 2;
> violation: right hand side is violated by 1,
>
> what does it mean “violation: right hand side is violated by 1”? Does it
> mean that something in the solving process went wrong? Or is it a
> correct output?

It means that in the solution that is checked at this place, all 3 
binary variables are at one, even though the constraint forbids this. 
That is, the solution is not feasible.

To say whether something is wrong depends on whether it was expected 
that the solution is feasible or if it could also be infeasible.
If you get this message after the solving process when the best solution 
is checked, then it indicates that something went wrong.

Stefan

>
> Thank you very much in advance.
>
> Yours faithfully,
> Rostislav Stanek
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