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List:       boost
Subject:    Re: [boost] [math] Summer of Code
From:       "John Maddock" <john () johnmaddock ! co ! uk>
Date:       2008-04-24 9:05:14
Message-ID: 017301c8a5eb$53321d70$bcea0352 () fuji
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Paul Baxter wrote:
>> I'm very interested in the SIMD part. What functions of the math
>> toolkit would be targeted? Also, will this project create facilities
>> that I can use SIMD hardware with my own calculations? For example, I
>> would very much like to do ray/box intersection tests by using SSE.
>> Would that be possible after the SOC?
>>
>> This project might be of interest to you, in case you didn't know
>> about it:
>>
>> http://www.pixelglow.com/macstl/
>
> Glen Low at PixelGlow was very positive and proactive with macstl
> (smart cookie!) but sadly didn't get as much interest and commercial
> support as he needed to put bread on the table.

This is tricky isn't it: these things are good academic projects, but are 
very much "niche" applications :-(

The other issue is portability: although several platforms support 
vectorised float operations (including NVidia graphics cards if you want to 
gain some extra cores!), only Intel supports vectorised double operations as 
far as I know, and it's these latter that I'm interested in :-(

> I found MacSTL reasonably good but not that well supported on x86
> (much better on Altivec). Glen was a little prone to hyperbole in
> some of his speedup claims. I also found that the Intel compiler was
> reasonably good at optimising C (gulp) code to achieve the same sorts
> of speeds (particularly relevant for complex numbers which are
> hopelessly SIMD optimised in C++ by Intel).
>
> Perhaps also take a look at www.codesourcery.com and their VSIPL++
> option.
> It uses expression templates to coalesce sequences of ops and makes
> use of SIMD operations and also utilises underlying vector libs if
> available but as with macstl, has a more restrictive license.

Unfortunately BLAS/FFT style operations, aren't the ones we really need in 
this project (think vectorised Horner evaluations and the like) :-(

Cheers, John.



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