[SciPy-dev] fft code for testing

[Chuck Harris]

Thanks Eric,
 
>                  Fast Fourier Transform
> ====================================================
>            |    real input     |   complex input
> ----------------------------------------------------
>  size      |  scipy  | testing |  scipy  | testing
> ----------------------------------------------------
>        256 |    2.68 |    1.97 |    3.52 |    2.40  (10000 calls)
>        512 |    1.82 |    1.25 |    2.76 |    1.69  (5000 calls)
>       1024 |    1.48 |    0.92 |    2.47 |    1.48  (2000 calls)
>       2048 |    1.22 |    0.77 |    2.24 |    1.22  (1000 calls)
>       4096 |    1.17 |    0.76 |    2.29 |    1.29  (500 calls)
>       8192 |    1.29 |    1.08 |    3.18 |    2.17  (200 calls)
>      16384 |    1.57 |    1.20 |    4.34 |    2.14  (100 calls)
>      32768 |    2.94 |    1.29 |    6.40 |    3.70  (50 calls)
>      65536 |    4.54 |    2.20 |    6.54 |    7.09  (20 calls)
>     131072 |    5.02 |    3.30 |    7.15 |    7.61  (20 calls)
>     262144 |    5.01 |    3.55 |    7.34 |    7.37  (10 calls)
> .
> ----------------------------------------------------------------------
> 

That big jump (in)efficiency at 65536 is sure curious, especially as
it doesn't show up in the real transforms. Hmmm .... I need to do
some experiments with blocking.

Chuck