Thanks.... It was a cute result. You seem to be doing good things in NYC for J . Tama says "hello", too.
Linda -----Original Message----- From: programming-boun...@jsoftware.com [mailto:programming-boun...@jsoftware.com] On Behalf Of Devon McCormick Sent: Tuesday, March 20, 2012 10:28 AM To: Programming forum Subject: Re: [Jprogramming] A Universal Domain and A Big Surprise Linda - the "<:1" is giving you zero and you're dividing by this, hence the infinities except for the first one as "0%0" is one in J. Regards, Devon On Tue, Mar 20, 2012 at 4:01 AM, Linda Alvord <lindaalv...@verizon.net> wrote: > I wrote a function d to provide a domain that is appropriate for > either rectangular or polar plots. Here's what it looks like. > > T=:2p1 > d=: 13 :'(0{x)-(-/x)*(i.>:y)%y' > (0,T) d 8 > 0 0.785398 1.5708 2.35619 3.14159 3.92699 4.71239 5.49779 6.28319 > > (0,T%2) d 8 > 0 0.392699 0.785398 1.1781 1.5708 1.9635 2.35619 2.74889 3.14159 > (0,1) d 8 > 0 0.125 0.25 0.375 0.5 0.625 0.75 0.875 1 > (_1,1) d 8 > _1 _0.75 _0.5 _0.25 0 0.25 0.5 0.75 1 > > Here's what David Ward Lambert showed me as a shortcut if i: is desired: > > i: 1j8 > _1 _0.75 _0.5 _0.25 0 0.25 0.5 0.75 1 > > My first version, which I rejected was based on the number of atoms in > the list rather than the number of intervals. I thought I would > replace y-1 by <:y . Intead I typed <:1 . The result is > confounding! Happy hunting for an explanation. > > da=: 13 :'(0{x)-(-/x)*(i.y)%y-1' > (0,1) da 9 > 0 0.125 0.25 0.375 0.5 0.625 0.75 0.875 1 > da=: 13 :'(0{x)-(-/x)*(i.y)%<:1' > (0,1) da 9 > 0 _ _ _ _ _ _ _ _ > > Just another little "wake up" exercise. > > The "good d" looks like this in tacit form: > > d > (0 { [) - ([: -/ [) * 0 %~ [: i. ] > > Linda > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm -- Devon McCormick, CFA ^me^ at acm. org is my preferred e-mail ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
