Monte Carlo method for finding pi

pi-monte-carlo.py

from __future__ import division
import random
import sys
import math


def main():
    # The first command line argument defines the number of iterations
    # of the algorithm. The default value is 400.
    if len(sys.argv) > 1:
        num_iters = int(sys.argv[1])
    else:
        num_iters = 400

    # How many of the randomly generated points are inside the circle.
    points_in_circle = 0

    # Generate num_iters points (between (0,0) and (1,1)) and check if 
    # they are inside the circle.
    for i in xrange(num_iters):
        x, y = random.random(), random.random()

        if math.pow(x, 2) + math.pow(y, 2) <= 1:
            points_in_circle += 1

    # Use the formula for the area of a circle to find pi.
    pi = (points_in_circle / num_iters) * 4

    print 'Pi is', pi


if __name__ == '__main__':
    main()