Boost logo

Boost :

Subject: Re: [boost] Back to Boost.SIMD - Some performances ...
From: Joel Falcou (joel.falcou_at_[hidden])
Date: 2009-03-26 14:02:15

Stephan Tolksdorf a écrit :
> I'm sure that if you manage to write a platform and compiler
> independent library for vectorized basic math functions that can
> compete with Intel's MKL in terms of accuracy and speed, there'll be a
> lot of interest in your library.
Being almost on-par is already OK. But those tests are usign the MKL
array and not raw calls of functions. I bet that MKL array use blocking
and/or pipelining.

> Could you comment on what vector size you used for your timings and
> whether
We used same settings as MKL aka 100 vector of floats and 1000
iterations per functions.
> you think the library will provide competitive performance for the
> specific vector sizes of N=1,2,3,4?
Well, Boost.SIMD has a different scope. It provides pervasive acces to
SIMD facility (SIMD vector of 1 element are rather useless)
vector of 2 and 4 that can be mapped on proper native intrinsic type
will benefit from SIMD acceleration, other will benefit from agressive
inlining of boost::array.
> Also, do the functions properly handle denormals and overflows?
We try as hard as we can. That's the main activity now, providing High
Accuracy for functiosn that currently don't.
We also plan to support LA and EP mode.

> BTW, are you aware of the Eigen library:
Well, considering my PHD thesis was writing such a library I am.
I send you back the question, are you aware of NT2 : ?

cause it's the project this Boost.SIMD is actually extarcted from ;)

Joel Falcou - Assistant Professor
PARALL Team - LRI - Universite Paris Sud XI
Tel : (+33)1 69 15 66 35

Boost list run by bdawes at, gregod at, cpdaniel at, john at