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Date: Wed, 01 Jun 2011 11:10:33 -0700
From: Ethan Furman <ethan@stoneleaf.us>
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Subject: Re: float("nan") in set or as key
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.python:6812

Carl Banks wrote:
> For instance, say you are using an implementation that uses
 > floating point, and you define a function that uses Newton's
 > method to find a square root:
> 
> def square_root(N,x=None):
>     if x is None:
>         x = N/2
>     for i in range(100):
>         x = (x + N/x)/2
>     return x
> 
> It works pretty well on your floating-point implementation.
 > Now try running it on an implementation that uses fractions
 > by default....
> 
> (Seriously, try running this function with N as a Fraction.)

Okay, will this thing ever stop?  It's been running for 90 minutes now. 
  Is it just incredibly slow?

Any enlightenment appreciated!

~Ethan~