Source code for pyutil.numerical.gcd_iter

#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Display an iterative method for determining the greatest common denominator.

Jan 17, 2019:

    Just added in :mod:`sys` so that we accept input from the user.


"""
import logging
import sys


def gcd_iter(a, b):
    """Find the greatest common denominator with 2 arbitrary integers.

    Parameters
    ----------
    a : int
        User provided integer
    b : int
        User provided integer

    Returns
    -------
    gcd : int
        Greatest common denominator.

    """
    orig_b = b
    orig_a = a
    if a > b:
        while b > 0:
            if a % b == 0 and orig_b % b == 0:
                return b
            b -= 1
    else:
        while a > 0:
            if b % a == 0 and orig_a % a == 0:
                return a
            a -= 1


if __name__ == "__main__":
    args = sys.argv[1:]

    logging.basicConfig(level=logging.WARNING)

    if len(args) == 2:
        a = args[0]
        b = args[1]

    try:
        a = args[0]
        b = args[1]
    except (NameError, IndexError):
        logging.error("Not enough args provided.")
        sys.exit()

    try:
        a = int(a)
        b = int(b)
    except TypeError as e:
        print(e)
        sys.exit()

    gcd = gcd_iter(a, b)
    print(gcd)