[Numpy-discussion] ANN: Numexpr 1.1, an efficient array evaluator

Olivier Grisel olivier.grisel@ensta....
Sat Jan 17 00:37:55 CST 2009


2009/1/16 Gregor Thalhammer <gregor.thalhammer@gmail.com>:
> Francesc Alted schrieb:
>>
>> Wow, pretty nice speed-ups indeed!  In fact I was thinking in including
>> support for threading in Numexpr (I don't think it would be too
>> difficult, but let's see).  BTW, do you know how VML is able to achieve
>> a speedup of 6x for a sin() function?  I suppose this is because they
>> are using SSE instructions, but, are these also available for 64-bit
>> double precision items?
>>
> I am not an expert on SSE instructions, but to my knowledge there exist
> (in the Core 2 architecture) no SSE instruction to calculate the sin.
> But it seems to be possible to (approximately) calculate a sin with a
> couple of multiplication/ addition instructions (and they exist in SSE
> for 64-bit float). Intel (and AMD) seems to use a more clever algorithm,

Here is the lib I use for the  transcendental functions SSE implementations:
http://gruntthepeon.free.fr/ssemath/

(only simple precision float though).

-- 
Olivier


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