If you want to write a propagator for this, the non-reified divmod propagator that is included in the just released 2.2.0 might be a good starting point.
Christian -- Christian Schulte, www.ict.kth.se/~cschulte/ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mauricio Toro Sent: Monday, August 25, 2008 3:40 PM To: gecode list Subject: Re: [gecode-users] Modulo operator Hello, I am trying to write this reified constraint. (a mod c = d) <-> b where a,c,d are IntVars and b is BoolVar. In the past, you recommend to represent A = (B - C) mod n as A = (B-C) + n * X. But, now I am wondering how can I write a reified propagator for (a mod c = d) <-> b. Thanks, Mauricio 2008/5/14 Guido Tack <[EMAIL PROTECTED]> Malcolm Ryan wrote: > I'd like to express the constraint: > > A = (B - C) mod n > 0 <= A < n > > for variables A,B,C and constant n. > > How would you advise doing this? The obvious answer is to add an extra > variable X: > > A = (B-C) + n * X > 0 <= A < n > > but I'm not sure if this is best. Can you advise? As there's no built-in propagator for the modulo constraint, you have to decompose into other constraints, so your solution should be ok. After all, it's just a linear equation with constant coefficients 1*A-1*B+1*C-n*X=0, right? And X will be determined as soon as A,B,C are, you don't even have to include X in the branching. Guido _______________________________________________ Gecode users mailing list [EMAIL PROTECTED] https://www.gecode.org/mailman/listinfo/gecode-users -- Mauricio Toro Bermudez Estudiante de Ingeniería de Sistemas Pontificia Universidad Javeriana, Colombia Stagiare à l'Ircam 1, place Igor-Stravinsky 75004 Paris, France de 2008 à 2009
_______________________________________________ Gecode users mailing list [EMAIL PROTECTED] https://www.gecode.org/mailman/listinfo/gecode-users
