# -----------------------------------------------------------------------------
# From Numpy to Python
# Copyright (2017) Nicolas P. Rougier - BSD license
# More information at https://github.com/rougier/numpy-book
# -----------------------------------------------------------------------------
import numpy as np


def mandelbrot(xmin, xmax, ymin, ymax, xn, yn, maxiter, horizon=2.0):
    def mandelbrot(z, maxiter):
        c = z
        for n in range(maxiter):
            if abs(z) > horizon:
                return n
            z = z*z + c
        return maxiter
    r1 = [xmin+i*(xmax-xmin)/xn for i in range(xn)]
    r2 = [ymin+i*(ymax-ymin)/yn for i in range(yn)]
    return [mandelbrot(complex(r, i), maxiter) for r in r1 for i in r2]