Hmmm. Implementing (a naïve one) is easy enough but I fear for us it would be not enough of general interest.
We are currently working on techniques where reification of everything is possible. Maybe that could be a solution. Christian -- Christian Schulte, www.it.kth.se/~cschulte/ -----Original Message----- From: Max [mailto:[email protected]] Sent: Tuesday, February 17, 2009 10:49 AM To: Christian Schulte Cc: 'gecode list' Subject: Re: [gecode-users] Reified Distinct Constraint I'm building a SMT like appraoch for integrating CSP into ASP. Each constraint is represented by a boolean atom that can be true or false, so ... i would be great to support a non n^2 allDistinct for the variables. With a reified version i could use the distinct constraint in the body of a rule as condition. So for SMT like systems reified versions of all constraints are welcome. Max Christian Schulte wrote: > No, not really. I do not know what this distinct would be good for. A more > useful one would be a soft distinct where the number of violations is > counted (there, one actually also could get some propagation). Check for > example: > http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.3.7071 > > What do you need a reified distinct for? > > Christian > > -- > Christian Schulte, www.it.kth.se/~cschulte/ > > > -----Original Message----- > From: Max [mailto:[email protected]] > Sent: Tuesday, February 17, 2009 10:32 AM > To: Christian Schulte > Cc: 'gecode list' > Subject: Re: [gecode-users] Reified Distinct Constraint > > Thank you for the quick answer. > Is this feature planned for the release of GeCode3.0? > I just found a mail in the archive of somebody requesting the same feature. > Currently i do use O(n^2) constraints for this, but i wanted to show > that i can transform it into a constant number of rules. > Thats why i would need the reified version. > > Max > > Christian Schulte wrote: > >> No, there is no reified version. The best you can do at emulating is use >> excessive reification: Create O(n^2) reified disequality constraints for >> > all > >> variable-variable pairs, and then the reified control variable is the >> conjunction of all the control variables from the disequalities. As said, >> not very good. >> >> Christian >> >> -- >> Christian Schulte, www.it.kth.se/~cschulte/ >> >> -----Original Message----- >> From: [email protected] [mailto:[email protected]] On Behalf >> Of Max Ostrowski >> Sent: Monday, February 16, 2009 2:21 PM >> To: gecode list >> Subject: [gecode-users] Reified Distinct Constraint >> >> I just found the distinct constraint, that hopefully makes all variables >> distinct. This could greatly reduce the number of constraints, as i am >> translating from a logic program. >> But i would need a reified version of the distinct constraint. >> I there any or can i at least emulate thie behaviour? >> >> Thank you in advance, >> Max >> >> > > > > _______________________________________________ > Gecode users mailing list > [email protected] > https://www.gecode.org/mailman/listinfo/gecode-users > > _______________________________________________ Gecode users mailing list [email protected] https://www.gecode.org/mailman/listinfo/gecode-users
