| Re: [eigen] Re: SSE square root |
[ Thread Index |
Date Index
| More lists.tuxfamily.org/eigen Archives
]
- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] Re: SSE square root
- From: Rohit Garg <rpg.314@xxxxxxxxx>
- Date: Fri, 27 Mar 2009 14:55:00 +0530
- Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=Up6r9tKgnAhNe/zMiyZT8cnsad/Mu1319l9NoFAjTnw=; b=rlLk6oCk/dD/t+lK76N68p1ntG4nOqXCBSYiw2K8XfTU2glRUB+ciHsPTPyQvPMifM PUUg7sHoei8KZFY4JHaYHSAvQ8jfKYtKOlbjICJxbTNYaaxTeVbd6C5/HwQakqG2R2K0 asPocuocl6mQL+W4V1DxR4HXURiXG1DOlVYug=
- Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=TE/pkXRSJvuTKrnsOPFeZj7qpxyYhTVDsOiqPBYVGvHyt87its5tQoBFfVQ9v8KObe dN2iex0rd+MZJj3VK/Yr2vayxwPih1b7mmflR/pli56eTTYkxn+oFt46jrVwnV+Z/TEV dmyARhOzjiIw4Tk2sePWM5klHb5Rc/armZdhg=
It could be, but I wrote the scaffolding to test the errors. I was
under the impression that only the ei_psqrt will make into the
trnscendental functions.h file
On Fri, Mar 27, 2009 at 2:50 PM, Christian Mayer <mail@xxxxxxxxxxxxxxxxx> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> This looks lika candidate for a templated version that takes the number
> of iterations as the template parameter...
>
> Rohit Garg schrieb:
>> I compared the absolute accuracy in the [0,1] interval and I found
>> that only one iteration is enough for accuracy purposes, which seems
>> about right.
>>
>> On Fri, Mar 27, 2009 at 1:02 PM, Rohit Garg <rpg.314@xxxxxxxxx> wrote:
>>> This file has my sse float implementation for square root. The SSE
>>> square root instruction has only 12 bits of precision so extra
>>> iterations of Newton Raphson may be neccessary. How many of the are
>>> neccessary, I don't know. the max error I was getting was O(1e-8) in
>>> [0,1]. The cephes implementation has square root only for limited
>>> range. They do some other hacks to take care of range. I'll look into
>>> implementing those later. For now, this should be an acceptable for
>>> the fast implementations of square root atleast.
>>>
>>> Regards,
>>>
>>> --
>>> Rohit Garg
>>>
>>> http://rpg-314.blogspot.com/
>>>
>>> Senior Undergraduate
>>> Department of Physics
>>> Indian Institute of Technology
>>> Bombay
>>>
>>
>>
>>
>
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.9 (GNU/Linux)
>
> iEYEAREIAAYFAknMml8ACgkQoWM1JLkHou368gCfb8zF8tx8rTExdofW24Z6Xe/m
> S/YAnj71fu2J7LWyaqB7tOOglY15E4Ng
> =kTgD
> -----END PGP SIGNATURE-----
>
>
>
--
Rohit Garg
http://rpg-314.blogspot.com/
Senior Undergraduate
Department of Physics
Indian Institute of Technology
Bombay