数学 - Python - HITCHIN' UP YOUR PYTHON WAGON - GUESSING AND CHECKING WITH CONDITIONALS - FINDING A SQUARE ROOT

Math Adventures with Python
An Illustrated Guide to Exploring Math with Code
楽天ブックス(Kobo)
紀伊国屋書店(Kinoppy)

開発環境

• macOS Mojave - Apple (OS)
• Emacs (Text Editor)
• Windows 10 Pro (OS)
• Visual Studio Code (Text Editor)
• Python 3.7 (プログラミング言語)

Math Adventures with Python: An Illustrated Guide to Exploring Math with Code (Peter Farrell(著)、No Starch Press)のPART Ⅰ(HITCHIN' UP YOUR PYTHON WAGON)、3(GUESSING AND CHECKING WITH CONDITIONALS)、EXERCISE3-2(FINDING A SQUARE ROOT)の解答を求めてみる。

コード

Python 3

#!/usr/bin/env python3


def average(*nums) -> float:
    return sum(nums) / len(nums)


def square_root(num, low, high, epsilon=0.01):
    guess = average(low, high)
    square = guess ** 2
    while abs(square - num) >= epsilon:
        if square < num:
            low = guess
        else:
            high = guess
        guess = average(low, high)
        square = guess ** 2
    return guess


nums = [200, 1000, 50000]
for num in nums:
    print(f'{num}: 約{square_root(num, 1, num)}')

for epsilon in [0.1, 0.01, 0.001]:
    print(f'誤差: {epsilon}')
    for num in nums:
        print(f'{num}: 約{square_root(num, 1, num, epsilon)}')

入出力結果(cmd(コマンドプロンプト)、Terminal、Jupyter(IPython))

$ python3 sample1.py
200: 約14.1419677734375
1000: 約31.622823238372803
50000: 約223.60678881779313
誤差: 0.1
200: 約14.1419677734375
1000: 約31.624252319335938
50000: 約223.60697507858276
誤差: 0.01
200: 約14.1419677734375
1000: 約31.622823238372803
50000: 約223.60678881779313
誤差: 0.001
200: 約14.142157554626465
1000: 約31.622763693332672
50000: 約223.60679754876764
$