| Re: [eigen] Re: SSE square root |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] Re: SSE square root
- From: Christian Mayer <mail@xxxxxxxxxxxxxxxxx>
- Date: Fri, 27 Mar 2009 10:20:31 +0100
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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
>>
>
>
>
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