Actually, this is a bug in the original code. Thanks Linda! It should be:
(d%2) > (?]) n$d The idea being that each row (domain) has half of it's possible values set. Which is different from what you suggest because you may get a row of all zeros which is already inconsistent and so there is no point in running arc consistency on it. Cheers, Mike On Mon, Nov 5, 2012 at 2:11 AM, Linda Alvord <lindaalv...@verizon.net>wrote: > I just began to ponder this thread. Do you think E is the same as D? > > D=. (n%2) > (?]) n$d > E=. ?(n,d)$2 > > Linda > > -----Original Message----- > From: programming-boun...@forums.jsoftware.com > [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Michal D. > Sent: Sunday, November 04, 2012 11:26 PM > To: programm...@jsoftware.com > Subject: Re: [Jprogramming] Arc consistency in J > > > >> variables. In other words, if we specify the constraint x < y it > > >> looks like either x1 < x2 or x2 < x1 is sufficient to satisfy arc > > >> consistency. In other words, i think we should always use the > > >> symmetric closure of the constraint. > > > > > >> Does this sound valid to you? > > > > > > Unfortunately not. There are no values that can satisfy x1<x2 and > x2<x1. > > > If this was the case all csps would have no solutions > > > > I meant x1<x2 OR x2<x1 > > > > So symmetric closure was the wrong term for me to use. > > > > But I think we want to be using intersection of the relationship with > > its inverse. > > > > Does that sound right to you? > > > > Sorry I missed the or. Unfortunately not, I mean you can have a constraint > like that if you want but you don't have to have to in general. I think > we're dwelling on an implementation detail. They (wikipedia) must just > have > the < constraint propagating both ways. > > My brain is fried but I did hack together an ugly search procedure. You > can > try it out on a sudoku puzzle if you want. For some reason I couldn't > generate it using the code you gave me. http://pastebin.com/2zPB4DBA > > Maybe we can update the printf docs to say: > load 'format/printf' > http://www.jsoftware.com/help/jforc/input_and_output.htm > > Cheers, > > Mike > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
