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Subject: Re: [boost] different matrix library?
From: DE (satan66613_at_[hidden])
Date: 2009-08-11 14:15:50

on 11.08.2009 at 21:52
 joel wrote :
> Best approach is always do, show, convince.
> I was burned with my own Boost.SIMD proposal.
> It's better to work first THEN show off.

> For my own work, see :


> and the old page at sourceforge :

> I had a bit of discussion in the ML before, with comaprison w/r to Eigen

i'll run through that links

for now listen
as i can see you are familiar to simd programming
so when i researched the expression template based impementation of
vector operations i tried to use sse2 though compiler intrinsics
(since they are de facto portable)
but i did not get any benefit for doubles
i think that's because load/store operations consumed boost from
actual add_pd's etc.
so evaluating something like (pairwise for sse2)

    vec + vec*scalar - vec + element_wise_mul(vec, vec)

yields the same time for sse2 and plain implementations
however for floats i got significant boost (~2 however not 4)
so since i prefer doubles i droped such simd optimizations (but they
are still easily possible)
i'm interested about what you can say on this


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