mandelbrot-numpy

#!/usr/bin/env python3
import numpy as np
from PIL import Image # Pillow fork of PIL
import time

w, h = 900, 720
xc, yc, scale = - 0.7, 0.005, 1.5
imax, zmax = 190, 50

t1 = time.time()
y, x = np.ogrid[(yc - scale) * h/w: (yc + scale) * h/w: 1j * h,
                 xc - scale: xc + scale: 1j * w ]
c = x + 1j*y
ones = np.ones_like(x*y)
its = np.zeros_like(ones)
z = c * 0
np.warnings.filterwarnings('ignore', '(overflow|invalid)')

for n in range(imax):
    itsmax = abs(z.imag) < zmax
    np.putmask(its, itsmax, n*ones)
    np.putmask(z, itsmax,  z * z + c)

backgnd = np.log1p(its + 0.1 - np.log2(np.log2(abs(z) + 1))) / 5.25
np.putmask(backgnd, itsmax, 0*ones)
tones = np.uint8(backgnd * 255)
blues = np.vstack(np.linspace(0.2, 1, 160)) ** (4, 2.5, 1)
sepias = np.vstack(np.linspace(1, 0, 96)) ** (1, 1.5, 3)
rgbcolors = np.uint8(np.vstack((blues, sepias)) * 255)
img = Image.fromarray(rgbcolors[tones], mode="RGB")
img.save("mand.png")
print("Elapsed time: {:7.2f} s".format(time.time() - t1))
img.show()