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Subject: Re: [geda-user] Apollon
From: John Doty <jpd AT noqsi DOT com>
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Date: Sun, 13 Sep 2015 17:14:04 -0600
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On Sep 13, 2015, at 5:00 PM, DJ Delorie <dj AT delorie DOT com> wrote:

> 
>>> Also, most rational vectors do not have a rational magnitude.
>> 
>> If you have a Pythagorean triple (x, y, h), x^2+y^2==h^2, it
>> represents an angle arctan(y/x).
> 
> Except that h is typically *not* an integer.  Once you go off-integer,
> you hit the FPU precision problem, because in the FPU all numbers are
> on a "grid”.

It is if (x, y, h) is a Pythagorean triple. By definition. https://en.wikipedia.org/wiki/Pythagorean_triple

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd AT noqsi DOT com