Re: "Discrete Hartley transform" vs " Discrete Fouuier transform"

On Oct 10, 1:15=A0pm, Eric Jacobsen <eric.jacob...@[EMAIL PROTECTED]
> wrote:
> Since processing power and memory are cheap these days everybody just
> plugs in FFTs. =A0 When computing or memory resources are hard to come
> by, though, the FHT can have some real advantages.

That's an old myth, but it's not true.

From a theoretical perspective, the best known FFT algorithms
specialized for real inputs have slightly fewer operations than the
best known FHT algorithms.  (Claims that FHTs save a factor of two
over FFTs for real data are bogus, and have been widely debunked in
the literature.)

From a practical perspective, the structure of FHT algorithms is
roughly similar to that of real-data FFT algorithms, so there don't
seem to be any significant implementation advantages one way or the
other. So, it comes down to who has optimized their code more, and
there are far more heavily optimized FFT libraries readily available
than FHT libraries.

Regards,
Steven G. Johnson