Javier Romero wrote:
> Thanks for the fast answer. I tried decomposing the last constraint into mul,
> sqr and linear rules, but i got the same result. I attached the code. I
> compiled it by doing
> g++ parallelepiped.cpp -lgecodeminimodel -lgecodeint -lgecodesearch
> -lgecodegist -lgecodedriver -o parallelepiped
Ok, now it's easier to see what's going wrong. The problem is that the
equation may hold, but it cannot be expressed using IntVars because of the
limited domains. In your decomposition, the first constraint that exposes the
problem is
sqr(*this,k,kk);
At this point, k is already at least 2000000, but kk was initialized as an
IntVar with domain Int::Limits::min..Int::Limits::max. Therefore, the problem
has no solution, as 2000000*2000000 > Int::Limits::max. This is expected and
correct behavior.
Unfortunately, the minimodel layer lets you express constraints that are
(semantically) satisfiable, but the introduction of intermediate IntVars makes
them unsatisfiable.
For your actual problem, there's no way around this limitation except
implementing IntVars with arbitrary precision (using e.g. the gmp library).
This would be possible, but it's not something we're planning to do anytime
soon.
Cheers,
Guido
--
Guido Tack, http://people.cs.kuleuven.be/~guido.tack/
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