Is there any logical reason why C.!.2 gives parity? I had to look this up and as a result am skeptical... Also, <: seems unnecessary.
Marshall -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Henry Rich Sent: Monday, October 04, 2010 8:14 PM To: Programming forum Subject: Re: [Jprogramming] Distinct Numbers in Rows and Columns 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
