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fractal [2011/04/12 23:45] – [Mandelbrot] cedricfractal [2011/04/12 23:47] cedric
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 ====== Iterated function system ====== ====== Iterated function system ======
 +
 +In mathematics, [[http://en.wikipedia.org/wiki/Iterated_function_system | iterated function systems]] or IFSs are a method of constructing fractals; the resulting constructions are always self-similar.
  
 {{:barnsley-1.png|}} {{:barnsley-1.png|}}
Line 143: Line 145:
  
 {{:mandelbrot-python.png|}} {{:mandelbrot-python.png|}}
 +
 +<code python>
 +try:
 +    import Numeric as nm
 +except:
 +    print "program requires the Numeric module"
 +    print "from --> http://numeric.scipy.org/"
 +    raise SystemExit
 +import Tkinter as tk
 +import Image # PIL
 +import ImageTk # PIL
 +# set width and height of window
 +#w ,h = 640, 600
 +#w ,h = 1280, 1200
 +w ,h = 2200, 2000
 +#w ,h = 2560, 2400
 +
 +class Mandelbrot(object):
 +    def __init__(self):
 +        """
 +        Create window
 +        """
 +        self.root = tk.Tk()
 +        self.root.title("Mandelbrot Set")
 +        self.create_image()
 +        self.create_label()
 +        # start event loop
 +        self.root.mainloop()
 +
 +    def draw(self, x1, x2, y1, y2, maxiter=30):
 +        """
 +        Draw the Mandelbrot set.
 +        """
 +        xx = nm.arange(x1, x2, (x2-x1)/w*2)
 +        yy = nm.arange(y2, y1, (y1-y2)/h*2) * 1j
 +        q = nm.ravel(xx+yy[:, nm.NewAxis])
 +        z = nm.zeros(q.shape, nm.Complex)
 +        output = nm.resize(nm.array(0,), q.shape)
 +        for iter in range(maxiter):
 +            z = z*z + q
 +            done = nm.greater(abs(z), 2.0)
 +            q = nm.where(done,0+0j, q)
 +            z = nm.where(done,0+0j, z)
 +            output = nm.where(done, iter, output)
 +        output = (output + (256*output) + (256**2)*output) * 8
 +        # convert output to a string
 +        self.mandel = output.tostring()
 +
 +    def create_image(self):
 +        """"
 +        Create the image from the draw() string
 +        """
 +        self.im = Image.new("RGB", (w/2, h/2))
 +        # you can experiment with these x and y ranges
 +        self.draw(-2.13, 0.77, -1.3, 1.3)
 +        self.im.fromstring(self.mandel, "raw", "RGBX", 0, -1)
 +
 +    def create_label(self):
 +        """
 +        Put the image on a label widget
 +        """
 +        self.image = ImageTk.PhotoImage(self.im)
 +        self.label = tk.Label(self.root, image=self.image)
 +        self.label.pack()
 +
 +
 +if __name__ == '__main__':
 +    test = Mandelbrot()
 +</code>