NArray demo: Mandelbrot

Result image

Code

require 'narray'
require 'nimage'

def mandel(w,h)
  zoom=3.5

  z = ( NArray.scomplex(w,1).indgen!/w-0.65 )*zoom + 
      ( NArray.scomplex(1,h).indgen!/h-0.5 )*(zoom*1.im)
  c = z.dup
  a = NArray.sint(h,w)
  idx = NArray.int(h,w).indgen!

  for i in 1..30
    z = z**2+c
    idx_t,idx_f = (z.abs>2).where2
    a[idx[idx_t]] = i
    break if idx_f.size==0
    idx = idx[idx_f]
    z = z[idx_f]
    c = c[idx_f]
  end
  a
end

NImage.show mandel(400,400)

print "Hit return key..."
STDIN.getc

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