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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Ada noob here! Is Ada widely used?
Newsgroups: comp.lang.ada
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Date: Sun, 6 Jun 2010 09:39:19 +0200
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Date: 2010-06-06T09:39:18+02:00
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On Sat, 5 Jun 2010 14:16:42 -0700 (PDT), Maciej Sobczak wrote:

> On 5 Cze, 14:59, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
> wrote:
> 
>> As for different types of the real and imaginary parts, it would make
>> little or no sense because you can "rotate" numbers by multiplying them to
>> exp(j*angle).
> 
> Nobody said that such a "rotation" must make sense in every single
> application domain. If it does not make sense in a given domain, then
> it does not have to be supported.

No, in this case the domain is set, it the complex field.

> I can perfectly imagine a domain where only the addition/substraction
> operation for complex and multiplying/dividing complex by scalar are
> necessary.

Yes, that would be a different model of complex numbers. But the same
argument applies to any numerical type. There may be cases where
floating-point is unsuitable.

>> So the complex space must be isotropic
> 
> So it does not have to be and Ada, as a language that promotes careful
> selection of types for the given purpose, would be more consistent by
> allowing separate base types for both components.

Polar representations were far more useful, or complex intervals
(rectangular, elliptic), to name some.

> Otherwise the model is simplified. Not necessarily bad, but certainly
> simplified.

You cannot have a model for each case. This is why I keep on arguing for a
better type system, where you could define your own models implementing
abstract classes like, in this case, complex field.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de