Python/maths/continued_fraction.py

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"""
Finding the continuous fraction for a rational number using python
https://en.wikipedia.org/wiki/Continued_fraction
"""
from fractions import Fraction
from math import floor
def continued_fraction(num: Fraction) -> list[int]:
"""
:param num:
Fraction of the number whose continued fractions to be found.
Use Fraction(str(number)) for more accurate results due to
float inaccuracies.
:return:
The continued fraction of rational number.
It is the all commas in the (n + 1)-tuple notation.
>>> continued_fraction(Fraction(2))
[2]
>>> continued_fraction(Fraction("3.245"))
[3, 4, 12, 4]
>>> continued_fraction(Fraction("2.25"))
[2, 4]
>>> continued_fraction(1/Fraction("2.25"))
[0, 2, 4]
>>> continued_fraction(Fraction("415/93"))
[4, 2, 6, 7]
>>> continued_fraction(Fraction(0))
[0]
>>> continued_fraction(Fraction(0.75))
[0, 1, 3]
>>> continued_fraction(Fraction("-2.25")) # -2.25 = -3 + 0.75
[-3, 1, 3]
"""
numerator, denominator = num.as_integer_ratio()
continued_fraction_list: list[int] = []
while True:
integer_part = floor(numerator / denominator)
continued_fraction_list.append(integer_part)
numerator -= integer_part * denominator
if numerator == 0:
break
numerator, denominator = denominator, numerator
return continued_fraction_list
if __name__ == "__main__":
import doctest
doctest.testmod()
print("Continued Fraction of 0.84375 is: ", continued_fraction(Fraction("0.84375")))