I made a simple Latin square and tried your definition. z=:3 3$1 2 3 2 3 1 3 1 2 z 1 2 3 2 3 1 3 1 2 hr=:-.@(0&e.)@:(C.!.2)@(,|:)@:<:"2 hr z 1 hr >:z 0
I think that incrementing all numbers in z should still produce a Latin square. On Mon, Oct 4, 2010 at 7:13 PM, Henry Rich <[email protected]> wrote: > I got to > > -.@(0&e.)@:(C.!.2)@(,|:)@:<:"2 > > as the test for whether the item is a Latin square. I have been trying > to find some cool test, without success. > > Henry Rich > > On 10/4/2010 7:37 PM, Roger Hui wrote: > > Great minds think alike, eh? (But I think you > > need to test your expressions ;-) Go to > > http://www.jsoftware.com/jwiki/Essays/KenKen > > and look about a third of the way down, > > > > q #~ (8$15) -:"1 (+/"1 ,. +/"2) q{0,2^i.4 > > > > The initial effort in your previous msg is also > > similar to my initial effort. > > > > > > > > ----- Original Message ----- > > From: Marshall Lochbaum<[email protected]> > > Date: Monday, October 4, 2010 16:28 > > Subject: Re: [Jprogramming] Distinct Numbers in Rows and Columns > > To: 'Programming forum'<[email protected]> > > > >> Here's a funny--and much faster--one: > >> p=.p:i.n > >> *./"1 (*/p) = (*/"2 ,. */"1) q{p > >> > >> Actually, I suppose it is better to do it with addition, so > >> p=.2^i.n > >> *./"1 (+/p) = (+/"2 ,. +/"1) q{p > >> > >> Marshall > >> > >> -----Original Message----- > >> From: [email protected] > >> [mailto:[email protected]] On Behalf Of Roger Hui > >> Sent: Monday, October 04, 2010 6:41 PM > >> To: Programming forum > >> Subject: [Jprogramming] Distinct Numbers in Rows and Columns > >> > >> An interesting puzzle arising from the KenKen solver: > >> q is an array with shape (m,n,n) and (,q) e. 1+i.n . > >> Which items of q have 1+i.n in each row and in each column? > > ---------------------------------------------------------------------- > > 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
