[Chicago] Pi generator again

[kirby urner]

I just noticed the formatting of the Pi generator in the Chipy
archives came out like total crap:

http://mail.python.org/pipermail/chicago/2013-April/010969.html

Sorry about that.

Here's a link to where the formatting worked:

http://mail.python.org/pipermail/edu-sig/2012-December/010729.html

I'm gonna blame my slowness to find the Plaintext option in the newest
Gmail interface.

Trying again here with the Python:

def pi_digits():
    k, a, b, a1, b1 = 2, 4, 1, 12, 4
    while True:
        p, q, k = k*k, 2*k+1, k+1
        a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1
        d, d1 = a/b, a1/b1
        while d == d1:
            yield int(d)
            a, a1 = 10*(a%b), 10*(a1%b1)
            d, d1 = a/b, a1/b1

(if that didn't come through in Plaintext, with indentation, I'm
sorry, I selected it many times)

Kirby

(in Portland (alien lurker))

PS:   I have since showed off generator versions of:

Gregory coefficients:
http://mail.python.org/pipermail/edu-sig/2013-April/010829.html

Bernoulli Numbers:
http://mail.python.org/pipermail/edu-sig/2013-April/010831.html

I was inspired by Raymond Hettinger's talk on how cool generators are,
among other Python features (Pycon keynote). I agree.