Mandelbrot Microscope

Jeff Epler jepler at unpythonic.net
Fri Jul 9 02:41:03 CEST 2004


Here's a program which calculates a similar result to yours using
numarray.  It calculates a 50x50 grid to 500 iterations in 3 seconds on
a 750MHz machine.  I didn't run yours so I don't know how this compares.

Hm, timeit.py says that your function runs in 2 ms per point with DEPTH=500
given the point 0+0j, and of course runs faster on points that escape.
Your program may run faster than the numarray implementation, or it
might be a wash. (2ms * 50 * 50 == 5 seconds)

This isn't a natural application for numarray.


from numarray import *

DEPTH = 500

def coords(x0, y0, x1, y1, w, h):
    rx = arange(w).astype(Float32) * (x1-x0) / (w-1) + x0
    ry = arange(w).astype(Float32) * (y1-y0) / (h-1) + y0
    return add.outer(rx * 1j, ry)

def f(z):
    C = z.copy()
    d = zeros(z.shape)

    for c in range(DEPTH):
        z = z*z - C
        zz = abs(z) > 3
        #print zz; print
        d += where(zz, 1, 0)
        if not (c % 8):  # keep contents of z from overflowing
            z = where(zz, 10, z)
    return d 

# 20x20 prints nicely on the screen in numbers
c = coords(-1.5, -1.5, 1.5, 1.5, 20, 20)
print f(c)/10
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