what's the precision of fractions.Fraction?

[Peter Pearson]

On Fri, 19 Nov 2010 07:29:59 -0800 (PST), RJB <rbotting at csusb.edu> wrote:
> Does Fractions remove common factors the way it should?
>
> If it does and you want to find the closest fraction with a smaller
> denominator i think tou'll need some number theory and continued
> fractions.

No heroics required, finding the greatest common divisor is fast.
And if this simple test is indicative, the fractions module reduces:

>>> x = fractions.Fraction( 2**100, 3 )
>>> y = fractions.Fraction( 7, 2**101 )
>>> z = x * y
>>> print x._numerator, x._denominator
1267650600228229401496703205376 3
>>> print y._numerator, y._denominator
7 2535301200456458802993406410752
>>> print z._numerator, z._denominator
7 6


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