From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Ada 95 ARCTAN function
Date: Thu, 1 Mar 2007 20:43:20 +0100
Date: 2007-03-01T20:43:07+01:00 [thread overview]
Message-ID: <14xgo99a35l6$.1gbe878d71ue8$.dlg@40tude.net> (raw)
In-Reply-To: 1172775505.390886.213420@t69g2000cwt.googlegroups.com
On 1 Mar 2007 10:58:25 -0800, saag wrote:
> Does the ARCTAN(y,x) function in the ADA.NUMERICS package provide the
> same results an atan2 function call in c? I'm trying to find out if
> Ada supplies an atan2 function (that gives an appropriate answer based
> on the quadrant the original point lies in)
A.5.1 (11) states that arctan (y, x) yields the result in the quadrant of
the point (x,y). I.e. (with circle=2pi)
| y>0 | y<0
-------+-----------+----------
x>0 | 0..pi/2 | -pi/2..0
| |
x<0 | pi/2..pi | -pi..-pi/2
When x is negative and y is approaches 0 changing its sign, it gets
instable (either pi or -pi). Argument_Error is propagated when x and y are
0.
(I cannot tell how this corresponds to the semantics of atan2)
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2007-03-01 19:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-01 18:58 Ada 95 ARCTAN function saag
2007-03-01 19:38 ` Jacob Sparre Andersen
2007-03-01 20:03 ` Adam Beneschan
2007-03-04 21:16 ` Keith Thompson
2007-03-01 19:43 ` Dmitry A. Kazakov [this message]
2007-03-01 21:39 ` saag
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