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How about adding rational fraction to Python?

Lie Lie.1296 at gmail.com
Sat Feb 16 17:10:28 EST 2008 
On Feb 17, 4:25 am, Carl Banks <pavlovevide... at gmail.com> wrote:
> On Feb 16, 3:03 pm, Lie <Lie.1... at gmail.com> wrote:
>
> > Although rationals have its limitations too, it is a much
> > better choice compared to floats/Decimals for most cases.
>
> Maybe that's true for your use cases, but it's not true for most cases
> in general.

OK, that might have been an overstatement, but as I see it, it is
safer to handle something in a Fraction compared to floats (which is
why I uses fractions whenever possible in non-computer maths).

> Rationals are pretty useless for almost any extended calculations,
> since the denominator tends to grow in size till it's practically
> unusbale, which means you have to periodically do non-exact reductions
> to keep things running, and if you do that you might as well be using
> floating point.

Rationals aren't that good if the same piece of variable is to be
calculated again and again because of its growth, but there are a lot
of cases where the data would only require five or six or so
operations done on it (and there are thousands or millions of such
datas), rationals is the perfect choice for those situations because
it is easier to use thanks to the comparison safety. Or in the
situations where speed isn't as important and accuracy is required,
Fraction may be faster than decimal and more accurate at the same time
(someone need to test that though).

> Rationals have their occasional special purpose uses, but for most
> cases they're at best marginally better then floats and more often
> incomparably worse.
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