Rational numbers

[Larry Bates]

Martin Manns wrote:
> Hi,
> 
> I am starting to use rationals and since I found no batteries included,
> I tried out the mxNumber package.
> 
> However, I get strange warnings on comparison operations
> (which however seem to yield correct results):
> 
> ---
> $ python
> Python 2.4.3 (#1, Jan 15 2007, 15:46:19) 
> [GCC 4.1.1 (Gentoo 4.1.1-r3)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> from mx.Number import *
>>>> a=Rational(0,1)
>>>> a
> 0/1
>>>> str(a)
> '0.0'
>>>> b=-5000000000000000000000000000000000000000000000000000000000
>>>> b
> -5000000000000000000000000000000000000000000000000000000000L
>>>> a==b
> __main__:1: RuntimeWarning: tp_compare didn't return -1, 0 or 1
> False
> ---
> 
> How do I get rid of these warnings?
> 
> Is there any rational number library around that
> 1) is comparably fast for large denominators
> 2) allows deriving types from Rationals without wrapping?
> 
> Regards
> 
> Martin
> 
> P.S. The respective mailing list does not like me, so that I try my
> luck here.

I quick search of Google turned up:

http://books.google.com/books?id=1Shx_VXS6ioC&pg=PA625&lpg=PA625&dq=python+rational+number+library&source=web&ots=BA8_4EXdQ4&sig=aDEnYA99ssKe7PSweVNyi8cS2eg
http://calcrpnpy.sourceforge.net/clnum.html
http://gmpy.sourceforge.net/

-Larry