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RE: ocaml, simd, & fftwgel RE: [Caml-list] Caml productivity.
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Date: -- (:)
From: Noel Welsh <noelwelsh@y...>
Subject: RE: ocaml, simd, & fftwgel RE: [Caml-list] Caml productivity.
--- "Gurr, David (MED, self)" <David.Gurr@med.ge.com>
wrote:
> 
> But do they do a better job than fftwgel or Spiral
> or Atlas?

I have no idea :)
 
> Is SAC available for public inspection?

Yeah: http://www.informatik.uni-kiel.de/~sacbase/

I couldn't find a paper that describes how ATLAS is
implemented. I'm guessing the most important
optimisations are blocking (dependant on the cache
size) and condensing consequetive array transversals.
SAC does both these optimisations.

> Once you do this, it is much less
> clear what
> the value added of the C compiler is.  In
> particular, the amount of 
> refinement that would be needed to get ocamlopt to
> match C compilers
> at this task might be relatively small ... since C
> is notoriously
> difficult to optimize even without SIMD.

Yeah, it is kinda ironic that C is famous for
generating such fast C.  The functional model (pure
functional code is essentially an SSA register
machine) is much closer to current hardware than the C
every-has-an-address/stack model.  So it should be
possible to get fast code out of a functional language
with less effort than C.  It is also a bit amusing,
and a bit sad, that Java and .Net both use a stack
model (it's like they want slow code!)

Noel

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