[SciPy-user] slow fft time

[Perry Greenfield]

You do realize that 21001 is prime, and that FFTs are not 'fast' for 
prime numbers of elements?
Try padding the array to make it a power of 2 number of elements (or at 
least a product of many
small primes)

Perry Greenfield

On May 14, 2005, at 8:20 PM, Ryan Krauss wrote:

>  I thought maybe I had screwed something up in my install and it 
> wasn't using ATLAS or something, but I ran this same code from windows 
> where I had in stalled from 
> SciPy_complete-0.3.2.win32P4SSE2-py2.3-num23.5.exe and 
> Numeric-23.8.win32-py2.3.exe.  It takes even longer in windows - maybe 
> 20secs (I am ordinarily running FC3 linux with kde).
>
>  Ryan
>
>
>  Ryan Krauss wrote:
>  I am trying to process some experimental data and I need to do a 
> bunch of fft's.  The time domain matrices are column vectors that are 
> 21001 elements and there are 3 columns.  It is taking 7 seconds or so 
> to execute the fft command:
>
>  In [73]: shape(curtmat)
>  Out[73]: (21001, 3)
>
>  In [74]: type(curtmat)
>  Out[74]: <type 'array (scipy)'>
>
>  In [75]: fftmat=fft(curtmat,None,0)
>
>  Am I doing something wrong?  Does this seems like a normal ammount of 
> time to anyone else?  What can I do to make this better?
>
>  Ryan
>
>
>
> _______________________________________________
> SciPy-user mailing list
>  SciPy-user at scipy.net
>  http://www.scipy.net/mailman/listinfo/scipy-user
>
>
>  _______________________________________________
> SciPy-user mailing list
> SciPy-user at scipy.net
> http://www.scipy.net/mailman/listinfo/scipy-user