Source code for concurrent.framework.samples.mandlebrot.mandle

import numpy as np
from pylab import imshow, show
from timeit import default_timer as timer

import time
start_time = []

[docs]def time_start():
        global start_time
        start_time.append(time.time())

[docs]def time_end(tag):
        global start_time
        start = start_time.pop()
        if start >= 0:
                print("{tag}: {ellapsed} s".format(tag=tag, ellapsed=time.time() - start))

[docs]def mandel(x, y, max_iters):
    """
        Given the real and imaginary parts of a complex number,
        determine if it is a candidate for membership in the Mandelbrot
        set given a fixed number of iterations.
    """
    c = complex(x, y)
    z = 0.0j
    for i in range(max_iters):
        z = z*z + c
        if (z.real*z.real + z.imag*z.imag) >= 4:
            return i

    return max_iters

[docs]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
    
    time_start()

    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

    time_end("mandle")

if __name__ == '__main__':
    image = np.zeros((1024, 1536), dtype = np.uint8)
    start = timer()
    create_fractal(-2.0, 1.0, -1.0, 1.0, image, 20) 
    dt = timer() - start
    
    print "Mandelbrot created in %f s" % dt
    imshow(image)
    show()