[SciPy-dev] Cleaning and fixing fft in scipy ?

[John Travers]

On 02/05/07, David Cournapeau <david at ar.media.kyoto-u.ac.jp> wrote:
>     - My understanding is that except for djbfft backend, all other
> backend implement fft of any size (eg different than 2^n); so for djbfft
> backend, for size different than 2^n, it uses a diffferent backend. For
> example, if FFTW (v2) is selected and djbfft detected, then the zfft
> function is effectively using 2 backend: djbfft and fftw2. Would it be a
> big problem if in djbfft case, the sizes != 2^n are always handled
> through a fixed backend (fftpack I guess) ?

Well, probably not, as people using djbfft probably know what they are
doing. But It does seem a bit drastic to drop from the fastest backend
to the slowest if say fftw or MKL is also installed. Especially as
this would provide lower performance than the current implementation.

But why is this necessary anyway? It is only decided at compile time
right? Or are you going the whole way and compiling all available back
ends and then letting people choose dynamically? That would be a nice
feature.

Cheers,
John