You might find http://www.jsoftware.com/pipermail/general/2003-March/015990.html useful, or at least interesting. A J6 version follows:
NB. -----Original Message----- NB. From: O^DAIRA, To^ru [mailto:[EMAIL PROTECTED] NB. Sent: Friday, February 28, 2003 10:02 PM NB. To: [EMAIL PROTECTED] NB. Subject: Re: [Jforum] Frractals - Mandelbrot Set P NB. NB. (1) Viewing Mandelbrot neighbours as the SecretSign(Thanks for inspiring) NB. Subject: RE: Jforum: Say-what-you-see series NB. Sent: Mon, 3 Feb 2003 01:34:15 -0000 NB. From: Mohammad Reza Jahanbin <[EMAIL PROTECTED]> NB. To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]> {"0 _&' SecretSign '@e@((o;e+(2:<|)@o)@((e=.>@{:);~C&+@:*:@o=.>@{.)^:11)C;0$~$C=:(12%~i:_20)j.~ /18%~_50+i.80 NB. (2) Viewing Mandelbrot set using viewmat load 'viewmat' require 'numeric bmp' Pos=: j./&steps/ _0.9 2.1 300,: _1.2 0 120 Lim=: -&Pos@:*:^:20 (0) viewmat | (}: , |.) (4: <: |)`(,:&4 )} |: Lim viewmat | (}: , |.) (4: <: |)`(,:&70)} |: Lim NB. rplc such t (4<:|t) with 70 NB. (3) Viewing Mandelbrot set using plot require 'plot' 'dot'plot <"1 |: +. (, +) (, 4> | Lim)# , Pos 'point'plot <"1 |: +. (, +) (, 4> | Lim)# , Pos NB. (4) FYI: Viewing Julia set using viewmat require 'numeric bmp' decmpx=: i.~ ~.@, NB. necessary because viewmat rejects complex arg. NB. " =: <"0 NB. neat but creates numerous small memory cells clattice=: j./&steps NB. dyad: substitution for region in the complex plane clattice=: (j.~/~ |.)&steps NB. transpose for math. graph. coord. NB. aNewtonRaphson1step4derivable=: 1 :'- x. % x.d.1' NB. aNewtonRaphson1step4underivable=: 1 :'- x. % 1e_3&(x."0 D:1)' NB. "underivable" here means "that d. can not transform as symbols" aNR1s4all=: f.1 :'- x % x(1 :''try. x d.1 catch. 1e_3&(x"0 D:1) end.'')' enlargeMat_x3 =: 3&#"1 @: (3&#) NB. for optinal use before laplacian laplacianoid_bw=: (>1 1;2 2)&(-:&[EMAIL PROTECTED]@~.@,;._3) nabloid_color =: (>1 1;2 2)&( [EMAIL PROTECTED]:@,;._3) foo =: _1 0 0 1&p. NB. 0 = _1 + x^3 ReRange=: _1 1 100 ImRange=: _0.5 1.5 100 Lim=: foo(aNR1s4all)^:_ ReRange(clattice) ImRange viewmat decmpx Lim viewmat laplacianoid_bw Lim NB. viewmat laplacianoid_bw enlargeMat_x3 Lim viewmat nabloid_color Lim > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:programming- > [EMAIL PROTECTED] On Behalf Of Ahmad Issa > Sent: Saturday, August 19, 2006 4:07 AM > To: Programming forum > Subject: Re: [Jprogramming] Mandelbrot > > I don't quite have the money to get the book (i'm still in highschool), > i'd > really appreciate it if you could write some code that i can study. > > regards, Ahmad > > On 8/19/06, Miller, Raul D <[EMAIL PROTECTED]> wrote: > > > > Ahmad Issa wrote: > > > I'm trying to plot some of the mandelbrot set. My > > > implementation is discouragingly slow, are there > > > any faster implementations in J? > > > > Presumably, yes: > > http://www.jsoftware.com/jwiki/Books#head-8ca3f3769d7a001e890dcbfef60fb0 > > 8276bce3d6 > > > > Inspecting your code, it looks like you've broken the > > problem into a bunch of more or less unrelated little > > pieces. To get better performance, you should > > eliminate unnecessary steps. For example, I would > > start by eliminating all your ext_* verbs and replacing > > them with something which treats the data in an > > array fashion (perhaps using inner product or something > > of that nature). > > > > Except where this introduces big-O problems, eliminating > > extra evaluation steps is one of the more obvious ways to > > improve J performance. > > > > -- > > Raul > > > > ---------------------------------------------------------------------- > > 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
