[Scip] Problem with Conflict Analysis

[Marc Pfetsch]

Dear Alexander,

the function SCIPvarGetLbAtIndex() contains a parameter in which you can 
specify whether the bound change in questions has already been applied. 
To which value have you set this value? In principle, you should be able 
to reconstruct the bound change at that time (using infervar and the 
above function).

Please also check whether the bound change via SCIPinferVarLbCons() 
actually changed the bound (check return values infeasible and tightened).

You can look at other examples of conflict resolution, e.g., 
cons_linearordering.c in examples/LOP. Please note that implementing 
conflict resolution always is a tricky thing.

If this does not explain the problem, we would need more details from 
you in order to be able to reconstruct the problem. Possibly off this 
list ...

Best

Marc


On 10.10.2013 15:32, Alexander Schnell wrote:
> Dear SCIP team,
>
> I implemented a Constraint Handler for a special
> project scheduling problem.
>
> In the CONS_RESPROP function, I try to explain the bound
> changes processed through the propagation algorithm implemented in
> the CONS_PROP function.
>
> In the function for the explanation generation, I observed a problem
> with the function SCIPvarGetLbAtIndex(...):
>
> In the propagation algorithm, the lower bound is propagated with
> the function SCIPinferVarLbCons(). I integrate the integer lower bound
> of the variable responsible for the processed bound change as an
> inferinfo in this function.
>
> In the CONS_RESPROP function, I compare the latter value with the actual
> lower bound of the responsible variable given by
> SCIPvarGetLbAtIndex(...) at the given bound change index.
>
> My problem is that these values are not the same, which should not be
> the case in my understanding.
>
> Thank you in advance for your help.
>
> Best regards,
> Alexander Schnell
>
>
>
>
>
>
>
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