Creating a simple continued fraction from a square root

a_cfrac.py

import math


def from_root(n):
    '''
    Construct a continued fraction from a square root. The argument
    `n` should be an integer representing the radicand of the root:

        >>> from_root(2)
        (1, [2])
        >>> from_root(4)
        (2,)
        >>> from_root(97)
        (9, [1, 5, 1, 1, 1, 1, 1, 1, 5, 1, 18])
    '''

    a0 = int(math.floor(math.sqrt(n)))
    r = (a0, [])
    a, b, c = 1, 2 * a0, a0 ** 2 - n
    delta = math.sqrt(4*n)

    while True:
        try:
            d = int((b + delta) / (2 * c))
        except ZeroDivisionError: # a perfect square
            return (r[0],)
        a, b, c = c, -b + 2*c*d, a - b*d + c*d ** 2
        r[1].append(abs(d))
        if abs(a) == 1:
            break
    return r

cfrac.py

import math
import fractions

def from_root(n):
    '''
    Construct a continued fraction from a square root. The argument
    `n` should be an integer representing the radicand of the root:

        >>> from_root(2)
        (1, [2])
        >>> from_root(4)
        (2,)
        >>> from_root(97)
        (9, [1, 5, 1, 1, 1, 1, 1, 1, 5, 1, 18])
    '''

    coeff = 1
    floor_part = floor_ = math.floor(math.sqrt(n))
    denom = n - floor_part ** 2
    exp = (int(floor_), [])

    while True:
        try:
            floor_ = math.floor((math.sqrt(n) + floor_part) / float(denom))
        except ZeroDivisionError: # perfect square
            return (exp[0],)

        if denom != 1:
            exp[1].append(int(floor_))
        floor_part = denom * floor_ - floor_part
        coeff = denom
        denom = n - floor_part ** 2
        common_div = fractions.gcd(coeff, denom)
        coeff /= common_div
        denom /= common_div

        if denom == 1:
            exp[1].append(int(floor_part + exp[0]))
            break

    return exp