From: hreba <f_hreba@yahoo.com.br>
Subject: Re: Trigonometric operations on x86 and x64 CPUs
Date: Sun, 18 Dec 2016 16:45:43 +0100
Date: 2016-12-18T16:45:43+01:00 [thread overview]
Message-ID: <ebnp98F2inuU1@mid.individual.net> (raw)
In-Reply-To: <295c603e-920d-4405-afb6-084d3d165112@googlegroups.com>
On 12/18/2016 03:19 PM, Robert Eachus wrote:
> On Sunday, December 18, 2016 at 5:09:55 AM UTC-5, already...@yahoo.com wrote:
>
> I am one of those other users. In paricular tangents near Pi/4 (90 degrees) have very large swings for small errors. A bad value of Pi can result in a very large negative value for the tangent instead of a very large positive value.
This seems to be a bad mathematical formulation of some problem, as it
is often the case when a very high numerical precision of a numerical
function is demanded. But tell me if I am wrong. Close to Pi/4 the
following relation holds:
tan (Pi/4 + phi) -> -1/phi, for phi -> 0,
so an approximation like this should be used for values close to Pi/4.
Is the angle really known with a precision which justifies a special
implementation of the trigonometric functions?
--
Frank Hrebabetzky +49 / 6355 / 989 5070
next prev parent reply other threads:[~2016-12-18 15:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-16 0:38 Trigonometric operations on x86 and x64 CPUs Robert Eachus
2016-12-16 14:00 ` Luke A. Guest
2016-12-16 20:16 ` Randy Brukardt
2016-12-16 23:20 ` Robert Eachus
2016-12-18 10:09 ` already5chosen
2016-12-18 14:19 ` Robert Eachus
2016-12-18 15:45 ` hreba [this message]
2016-12-18 15:47 ` already5chosen
2016-12-19 23:11 ` Randy Brukardt
2016-12-19 23:49 ` already5chosen
2016-12-20 5:27 ` Niklas Holsti
2016-12-20 8:37 ` Simon Wright
2016-12-20 9:12 ` G.B.
2016-12-20 18:01 ` already5chosen
2016-12-21 1:20 ` Randy Brukardt
2016-12-21 9:29 ` already5chosen
2016-12-16 20:50 ` Vadim Godunko
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