[SCIP] SCIP with signed and unsigned interger

[Jakob Witzig]

Hi Alessandro,

no, SCIP does not consider such scenarios.

By the way, I'm not sure whether your model does what it is supposed to 
do, e.g., you defined 'a' (and all other variables as well) as a 
continuous variable. Thus, there cannot be an overflow for 'a' at 2^{31}.

Cheers,
Jakob

Am 31.01.2017 um 16:08 schrieb Alessandro Danese:
> Good morning,
> I’m using SCIP to count the number of feasible solutions of a set of constraints.
> My constraints involve bitvector variables.
>
> Example:
> C1: x_1 + 256x_2 + 65536x_3 + 16777216x_4 -a = 0
> C2: 300 + a < 44
>
> Bounds
> 0 <=  x_1 <= 255
> 0 <=  x_2  <= 255
> 0 <=  x_3 <= 255
> 0 <=  x_4 <= 255
> 0 <=    a   <= 2^32
>
> The above introduced problem does not have any feasible solution.
> However, when the variable ‘a' is greater / equals to 2^31, then it has negative value because of overflow.
>
> Can SCIP consider also overflow scenarios to compute a feasible solution?
>
> Thank you for your help
> Kind regards,
>
> Alessandro Danese
>
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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