[SciPy-user] FFT speed ?

[Nils Wagner]

Samuel GARCIA wrote:
> Hello list,
>
> I have a problem with fft speed.
> could someone try this :
>
> from scipy import *
> import time
>
> a = rand((186888));t1=time.time();fft(a);t2=time.time();t2-t1
>
> # for me about 0.67791390419006348 s. on centrino 1.6GHz
>
> a = rand((186890));t1=time.time();fft(a);t2=time.time();t2-t1
>
> # for me about 1.622053861618042 s. on centrino 1.6GHz
>
> a = rand((186889));t1=time.time();fft(a);t2=time.time();t2-t1
>
> # the computation is infinit !!!! (no time to wait)
>
>
> Question : why is there a problem specialy for that size (186889) of fft ?
> It is not the only size with that problem.
>
>
> Thank
>
> Sam
>
>
>   
What you can find with help (fft) is ...

"This is most efficient for n a power of two"

Nils