Stupid Pi tricks for Pi Day

By Iddo on March 14th, 2010

π approximation script, from Stephen Chappell.

import sys
def pi():
    a, b, c, d, e, f = 1, 0, 1, 1, 3, 3
    while True:
        if a * 4 + b - c < c * e:
            yield e
            a, b, c, d, e, f = a * 10, (b - c * e) * 10, c, d, ((a * 3 + b) * 10) // c - e * 10, f
        else:
            a, b, c, d, e, f = a * d, (a * 2 + b) * f, c * f, d + 1, ((d * 7 + 2) * a + b * f) // (c * f), f + 2

digit = pi()
sys.stdout.write("%d.%d" % (digit.next(), digit.next()))
if len(sys.argv) < 2:
    prec = 5
else:
    prec = int(sys.argv[1]+1)
for i in range(prec):
    sys.stdout.write("%d" % digit.next())
print

To get Pi with a precision of 10 digits: