Calculate PI probabilistically

pi.py

#!/usr/bin/python

from __future__ import print_function
import math, random

acErr = 1e-5

def inCircle(x, y):
    """inCircle(x, y) iff (x, y) is in the circle of radius 1 centered at
origin"""
    return (math.sqrt(x**2 + y**2) - 1.0) <= acErr

def piGen():
    """Generates increasingly accurate values for PI"""
    S_circle, S_square = 0.0, 0.0
    while True:
        x, y = random.random(), random.random()
        S_circle += (1 if inCircle(x, y) else 0)
        S_square += 1
        yield (4*S_circle/S_square)

def run_pi():
    random.seed()
    print("Pi is 0.00000", end="")
    i = 0
    for p in piGen():
        i += 1
        if i % 25 == 0:
            print("\rPi is %1.5f" % p, end="")

if __name__ == "__main__":
    run_pi()