:orphan:

mandel
------


Calculate Mandelbrot set

.. raw:: html

  <video width="558" height="558" controls autoplay>
    <source src="../_static/examples/mandel.mov" type="video/mp4">
    <source src="../_static/examples/mandel.ogg" type="video/ogg">
  </video>

----

.. code-block:: python
    
    
    
    from timeit import default_timer as timer
    
    import numpy as np
    import gr
    
    
    def mandel(x, y, iters):
        c = complex(x, y)
        z = 0.0j
        ci = 0
        inc = 1
    
        for i in range(iters):
            z = z * z + c
            if (z.real * z.real + z.imag * z.imag) >= 4:
                return ci
            ci += inc
            if ci == 0 or ci == 255:
                inc = -inc
    
        return 255
    
    
    def create_fractal(min_x, max_x, min_y, max_y, image, iters):
        height = image.shape[0]
        width = image.shape[1]
    
        pixel_size_x = (max_x - min_x) / width
        pixel_size_y = (max_y - min_y) / height
        for x in range(width):
            real = min_x + x * pixel_size_x
            for y in range(height):
                imag = min_y + y * pixel_size_y
                color = mandel(real, imag, iters)
                image[y, x] = color
    
        return image
    
    
    x = -0.9223327810370947027656057193752719757635
    y = 0.3102598350874576432708737495917724836010
    
    f = 0.5
    for i in range(200):
        start = timer()
        image = np.zeros((500, 500), dtype=np.uint8)
        pixels = create_fractal(x-f, x+f, y-f, y+f, image, 400)
        dt = timer() - start
    
        print("Mandelbrot created in %f s" % dt)
        ca = 1000.0 + pixels.ravel()
    
        gr.clearws()
        gr.setviewport(0, 1, 0, 1)
        gr.setcolormap(13)
        gr.cellarray(0, 1, 0, 1, 500, 500, ca)
        gr.updatews()
    
        f *= 0.9