Find common factor to convert list of floats to list of integers

Question

I have a list of floats which comes from some other function. What I know is that in ideal world there exist a common factor which can be used to multiply each term to obtain list of integers. There could be some small numerical noise (~1e-14).

So for example

[2.3333333333333335, 4.666666666666667, 1.0, 1.6666666666666667]

here each term can by multiplied by 3 to obtain

[7.0, 14.0, 3.0, 5.0]

How can I find this term? We can assume integer solution exists.

Any helpful comments will be appreciated

Answer 1

Python's Fraction type can convert floating points to rationals with denominators under 1000000, and then you can find the lowest common denominator.

>>> from fractions import Fraction
>>> a = [2.3333333333333335, 4.666666666666667, 1.0, 1.6666666666666667]
>>> [Fraction(x).limit_denominator() for x in a]
[Fraction(7, 3), Fraction(14, 3), Fraction(1, 1), Fraction(5, 3)]

A straightforward way to find the least common multiple using the math.gcd function:

>>> denoms = [3,3,1,2]
>>> functools.reduce(lambda a,b: a*b//math.gcd(a,b), denoms)
6