sqrttest.py

#!/usr/bin/env python
#
# Author Dario Clavijo 2015
# GPLv3

# implementation acording to whikipedia: https://es.wikipedia.org/wiki/C%C3%A1lculo_de_la_ra%C3%ADz_cuadrada


def sqrt(x):
    r = x
    t = 0
    while t != r:
        t = r
        r = 0.5 * (x / r + r)
    return r


def sqrt(n):
    x = n
    y = 1
    e = 0.00000001
    while (x - y) > e:
        x = (x + y) / 2
        y = n / x
    return x


# given the x**2-2=0 condition we bruteforce an aproximation to sqrt(2)


def sqrttest():
    target = 2.0
    x = 2.0
    error = 1
    step = 0.5
    lower_error = 1
    i = 0
    c = 0
    last_aprox = None
    while error != 0:
        i = i + 1
        error = (x**target) - target
        x = x - (error * step)

        if error < lower_error:
            lower_error = abs(error)

        print(
            (
                "Count: %d, Aprox: %s, Error: %s, LowerError: %s"
                % (
                    i,
                    x,
                    error,
                    lower_error,
                )
            )
        )


sqrttest()