Re: [boost] performance of a linear algebra/matrix library

Subject: Re: [boost] performance of a linear algebra/matrix library
From: joel falcou (joel.falcou_at_[hidden])
Date: 2010-05-11 12:20:31

DE wrote:
> here a question arises:
> since a compiler is able to generate very fast code involving simd
> instructions is one supposed to provide simd-enabled implementation of
> a generic library? personally i think now that it is worthless
>   
Yeah sure, let's look how icc is able to vectorize arbitrary large 
arithmetic function
(like cos, sqrt etc that don't have a 1-1 SIMD intrinsic mapping). Other 
think. If you
work on dynamic memory, the compiler won't be doing any vectorization as 
the memory
may not be aligned properly.

Add to that loop with dependencies that human know how to rewirte (but 
not compiler),
arbitrary function support, SoA support for thing like complex or other 
ADS ...

Oh and, if your code as right, then both would have been inlined. That's 
what happen in our library
(which lead us to rmeove the unroll settings)

-- 
___________________________________________
Joel Falcou - Assistant Professor
PARALL Team - LRI - Universite Paris Sud XI
Tel : [phone]