From: Sander Land <sander.land@...>
Date: 2007-12-28T21:27:36+09:00
Subject: Re: Thought I'd share this and get some advice

On Dec 28, 2007 12:57 PM, Hiato Xaero <hiato3@gmail.com> wrote:
> I decided to take it upon myself to write a text Mandelbrot Set Generator in
> Ruby (seeing as I couldn't find any...)
>
> Anyway, here is the code, it's procedural style, not entirely utilizing Ruby
> to its fullest, but hey
>
> p ' '
> p "NOTE: Do not run this from a console that has less than 128 columns, 130
> to be safe! If you fail to do so, then you will see rubbish inplace of the
> mandelbrot set"
> p ' '
>
> i = -24.00
> until (i>=24)
>   k = -64.00
>   s = ''
>   until (k>=63)
>     p = 0
>     x = 0
>     y = 0
>     while ((x*x)+(y*y)<4)
>     xt = x*x - y*y + (k-23)/43.5
>     yt = 2*x*y + i/22
>     x = xt
>     y = yt
>     p = p + 6
>     break unless p<260
>   end
>   case p
>     when 1..10: s << 'A'
>     when 10..20: s << 'B'
>     when 20..30: s << 'C'
>     when 30..40: s << 'D'
>     when 40..50: s << 'E'
>     when 50..60: s << 'F'
>     when 60..70: s << 'G'
>     when 70..80: s << 'H'
>     when 80..90: s << 'I'
>     when 90..100: s << 'J'
>     when 100..110: s << 'K'
>     when 110..120: s << 'L'
>     when 120..130: s << 'M'
>     when 130..140: s << 'N'
>     when 140..150: s << 'O'
>     when 150..160: s << 'P'
>     when 160..170: s << 'Q'
>     when 170..180: s << 'R'
>     when 180..190: s << 'S'
>     when 190..200: s << 'T'
>     when 200..210: s << 'U'
>     when 210..220: s << 'V'
>     when 220..230: s << 'W'
>     when 230..240: s << 'X'
>     when 240..250: s << 'Y'
>     when 250..400: s << ' '
>   end
>   k = k + 1.00
> end
> p s
> i = i + 1.00
> end
>
> p ' '
> p "NOTE: Do not run this from a console that has less than 128 columns, 130
> to be safe! If you fail to do so, then you will see rubbish inplace of the
> mandelbrot set"
> p ' '
>
> gets()
>
> Finally, any feedback is welcome, and I'm just wondering if there isn't a
> more efficient way to do this.
>
> Anyway, cheers and thanks for reading
>
Hi Hiato,

Cool little script. The Mandelbrot is always nice to see. :)
Some comments:
First of all, the case statement in Ruby is really just equivalent to
if/elsif/elsif/..., so this is not very efficient. Better to replace
this with some arithmetic.

puts s over p s to avoid printing the quotes
i = i + 1.00  can be written as i += 1, but its probably better to
replace the 'until' loop with a for loop: for i in -24...24   (or just
(-24...24).each{|i| )

You can replace the loop on k and the s with a map call, and use
parallel assignment instead of xt/yt.


for i in -24...24
 puts (-64...63).map{|k|
   p = x = y = 0
   while ((x*x)+(y*y)<4)
    x, y = x*x - y*y + (k-23)/43.5, 2*x*y + i/22.0 # parallel
assignment, and /22.0 for automatic to_f on i
    p = p + 6
    break unless p<260
   end
   if p >= 250
     ' '
   else
     (?A + (p-1)/10).chr  # ?A.ord in 1.9
   end
 }.join
end