monte carlo approximation of pi

mc_pi.py

import random

def compute_pi():
    sm = 0.
    n = 10**7
    for i in range(n):
        x1, x2 = 2 * (random.uniform(0, 1) - 0.5), 2 * (random.uniform(0, 1) - 0.5)
        r = x1**2 + x2**2
        if r <= 1.0:
            sm += 1.
    return 4 * sm / n

print(compute_pi())