Article View: comp.sys.amiga.tech
Article #7112Re: Integer sine calculations?
From: wuethri
Date: Wed, 28 Nov 1990 16:14
Date: Wed, 28 Nov 1990 16:14
20 lines
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1537 bytes
In article <1990Nov23.175553.15606@msuinfo.cl.msu.edu> jap@convex.cl.msu.edu (Joe Porkka) writes:
>hebrais@olivier.IRO.UMontreal.CA (Philippe Hebrais) writes:
>
>So, 0.0 - 359.9 sounds like about 3600 32bit constants
>times two for each SIN and COS - right? Nope - I think
>I only used one 1800 32bit entry table and used that
>fact that SIN and COS look a lot alike, and things
>like sinx = -sin(360-x)
Not to forget that the symmetries are many more, in fact you need
to store only sine values from 0 to 90 degrees (1/4 of the sinus
periodic range, which is from 0 t0 360), as sin(x)=-sin(360-x),
and sin(90-x)=sin(90+x) and sin(270-x)=sin(270+x).
Greetings
Charles
--
Charles Wuethrich, Dept. of Computer Science | wuethri@ifi.unizh.ch
Univ. of Zurich, 8057 Zurich-Irchel, Switzerland | k114910@czhrzu1a.bitnet
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<1990Nov28.161429.17641@gorgo.ifi.unizh.ch>Path:
arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!yale!mintaka!bloom-beacon!eru!hagbard!sunic!mcsun!cernvax!chx400!unizh!gorgo!wuethriReferences:
<7336@hub.ucsb.edu> <1990Nov21.221825.10898@mdivax1.uucp> <HEBRAIS.90Nov23024202@olivier.IRO.UMontreal.CA> <1990Nov23.175553.15606@msuinfo.cl.msu.edu>Show Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!yale!mintaka!bloom-beacon!eru!hagbard!sunic!mcsun!cernvax!chx400!unizh!gorgo!wuethri From: wuethri@ifi.unizh.ch Newsgroups: comp.sys.amiga.tech Subject: Re: Integer sine calculations? Message-ID: <1990Nov28.161429.17641@gorgo.ifi.unizh.ch> Date: 28 Nov 90 16:14:29 GMT References: <7336@hub.ucsb.edu> <1990Nov21.221825.10898@mdivax1.uucp> <HEBRAIS.90Nov23024202@olivier.IRO.UMontreal.CA> <1990Nov23.175553.15606@msuinfo.cl.msu.edu> Sender: wuethri@gorgo.ifi.unizh.ch (Charles Wuethrich) Distribution: comp Organization: University of Zurich, Department of Computer Science Lines: 20