From: Robert Klemme <shortcutter@...>
Date: 2009-12-21T00:15:05+09:00
Subject: Re: Correcting complex math

On 20.12.2009 15:51, Colin Bartlett wrote:

> I'd also like to take the opportunity of this thread
> to suggest removing (!) something from Complex,
> unless anyone can make a good case for retaining it:

> The Complex numbers are not an "ordered field",
> at least not in any normally useful sense.
> 
> At the moment if either x or y is Complex
> then  x <=> y  is calculated as  x.abs <=> y.abs;
> 
> # File complex.rb, line 312
>   def <=> (other)
>     self.abs <=> other.abs
>   end
> 
> I think that can be misleading (see the examples above),
> and I would prefer it if "<=>" and "<", etc,
> were *not* defined for Complex,
> and if one wants to compare absolute values
> then one should do so explicitly.

Done.

robert@fussel ~
$ allruby -r complex -e 'p Complex(1,-1) <=> Complex(-1,1)'
ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-cygwin]
0
ruby 1.9.1p243 (2009-07-16 revision 24175) [i386-cygwin]
-e:1:in `<main>': undefined method `<=>' for (1-1i):Complex (NoMethodError)

robert@fussel ~
$

:-)

Kind regards

	robert

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