The power solution is nice (concise). juliaB inspires me for a new parallel GPU implementation and shows the benefit of using J for CUDA C algorithm development. Thank you all for your help!
On Sat, Aug 13, 2011 at 10:03 AM, R.E. Boss <[email protected]> wrote: > julia1=:4 : 0 > scale=.1.5 > jx=.scale*((-:DIM)-x)%-:DIM > jy=.scale*((-:DIM)-y)%-:DIM > c=._0.8j0.156 > a=.jx j. jy > <:{:((c + *:)@{. ,>:@{: )^:(1000 > |@{.)^:256 a,0 > ) > > But I would prefer a rank _ approach > > juliaB=: 3 : 0 NB. rank _ on a square of side y > scale=.1.5 > k=. scale * 1 - (i. % -:)y NB. avoid the use of j and i > c=._0.8j0.156 > a=. j./~ k > b=. 0 $~ y,y > for_r. i.256 do. > a=. c+ a * a > b=. b + r * 1000 < | a > a=. a * -.*b > end. > b=. b + 255 * 0 = b > ) > > (julia"0 0/~ -: julia1"0 0/~)i.DIM=:100 > 1 > (juliaB DIM) -: (julia1"0 0/~)i.DIM=:100 > 1 > > > R.E. Boss > > >> -----Oorspronkelijk bericht----- >> Van: [email protected] [mailto:programming- >> [email protected]] Namens Jan Jacobs >> Verzonden: vrijdag 12 augustus 2011 15:02 >> Aan: [email protected] >> Onderwerp: [Jprogramming] julia fractal >> >> ls, >> I'm preparing a course on GPU programming (NVIDIA's parallel graphics >> processor) for bachelor students using J. I have a need for a more tacit > form >> of a julia fractal than the one shown below, which is too much C-like. >> Suggestions are welcomed. >> Thanks in advance, >> Jan. >> >> >> load'graph' >> DIM=:400 >> >> NB. Julia function >> julia=:4 : 0 >> scale=.1.5 >> jx=.scale*((-:DIM)-x)%-:DIM >> jy=.scale*((-:DIM)-y)%-:DIM >> c=._0.8j0.156 >> a=.jx j. jy >> i=.0 >> while. i < 256 do. >> a=.(a * a) + c >> if. 1000 < | a do. i return. end. >> i=.i + 1 >> end. >> 255 >> ) >> >> viewmat (i.DIM)julia"0 0/ (i.DIM) >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > -- Jan Jacobs Esdoornstraat 33 5995AN Kessel W: www.sommaps.com T: +31 77 462 1887 M: +31 6 23 82 55 21 E: [email protected] ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
