Eugene McDonnell wrote about this in *Life: Nasty, Brutish, and Short*, 1988. The shortest expression came at the end, and in modern J can be written as:
Life=: 3 3 e.&O;._3 ] Don't like the use of the tesselation operator here? I quote from http://www.jsoftware.com/pipermail/programming/2010-September/020457.html People often accused Ken of including primitives in the language designed specifically to solve this or that problem. Over time, as the accusation occurs for problem after problem, he learned to take the accusation as a compliment. p.s. On the plane ride back from presenting the Life paper, Eugene and Ken invented fork. On Sat, Apr 5, 2014 at 8:32 AM, arthur whitney <[email protected]>wrote: > >john's game of life video: > > https://www.youtube.com/watch?v=a9xAKttWgP4&hl=en-GB&gl=GB&fmt=18 > > /apl > f←{↑1 ⍵∨.∧3 4=+/,¯1 0 1∘.⊖¯1 0 1∘.⌽⊂⍵} > > > nice! thanks. here is a k version > > > f:{3=s-x&4=s:2(+-1+/':)/x} > > > > > > -1+/': is window sum > > > 2(+f)/x > > says do f in 2 dimensions > > > > > > > On Sat, Apr 5, 2014 at 7:40 AM, Stevan Apter <[email protected]> wrote: > >> yes, i guess that tradeoff is to be expected. >> >> 2 3~ (!2)!2 3, >> 1 4 7~(!3)!1 4 7 >> >> so >> >> 2 3,1 4 7~(!5)!2 3 1 4 7 >> >> that makes sense to me. >> >> thanks for thinking about it. >> >> john's game of life video: >> >> https://www.youtube.com/watch?v=a9xAKttWgP4&hl=en-GB&gl=GB&fmt=18 >> >> >> On 4/5/14 10:23 AM, arthur whitney wrote: >> >> that dict idea is interesting. >> >> unfortunately for my ascii-k it shines light on some more overloads. >> i.e. leads to more primitives. >> (which makes sense. trade prims for types) >> >> >> atom funcs are fine.(+-*%..) >> >> but list funcs change, e.g. >> >> |`a`b!2 3 is `b`a!3 2 >> but would be `a`b!3 2 >> >> x,y (e.g. 2 3,1 4 7) is weird >> >> 2 3# (and 2 3_) would have to be new prims >> >> >> >> >> >> >> > Archives <https://www.listbox.com/member/archive/107499/=now> > <https://www.listbox.com/member/archive/rss/107499/22148033-f9df85d7> | > Unsubscribe > Now<https://www.listbox.com/unsubscribe/?member_id=22148033&id_secret=22148033-fa4bd084&post_id=20140405113258:8E1D3A28-BCD7-11E3-817D-94CF42143F95> > <http://www.listbox.com> > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
