[Haskell-cafe] Re: fftw bindings

[Bayley, Alistair]

> On Thu, Apr 19, 2007 at 05:46:49PM -0400, Al Falloon wrote:
> > >For us less knowledgable, what's fftw?
> > 
> > "Fastest Fourier Transform in the West." http://www.fftw.org/
> > 
> > Its cool, they use generative programming: an OCaml program 
> generates 
> > "codlets" in C that can be composed and tuned to the 
> specifics of your 
> > machine, then compiled into a blazingly fast FFT/DFT library.
> 
> But that's only the beginning of the coolness! fftw uses 
> runtime timings to
> optimize each fourier transform based on the behavior of the 
> computer on
> which it is being run--its cache, memory speed, CPU, etc.  
> The result being
> that fftw using portable C can beat out most hand-optimized 
> fftw libraries
> written in assembly! Steven (one of fftw's two authors) has done some
> incredible work on optimizations.  The most unbelievable (to 
> me) was that
> by eliminating negative constants from the generated code (using
> subtraction instead) they sped up the library on a particular 
> architecture
> by some some significant margin (I think I recall 20%).
> -- 
> David Roundy


Oleg has some related work
http://okmij.org/ftp/Computation/Generative.html#framework

"... The papers discuss in detail the generation of a straight-line C,
Fortran, etc. code for the power-of-two FFT. The papers show that with
the help of Abstract Interpretation we can exactly match the quality of
code generated by the well-known system FFTW. The second paper
demonstrates that our generated power-of-two FFT code has exactly the
same number of floating-point operations as that in codelets of FFTW.
The significant difference from FFTW is that we do not do any
intensional code analysis ... "

I don't know how useful this is.

Alistair
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