Computing FFT with Python NumPy 1.0

Robert Kern robert.kern at gmail.com
Thu Nov 2 01:18:31 CET 2006


mcdurr at gmail.com wrote:
> I recently installed Python 2.5 on Windows and also installed numpy
> 1.0. 

You will want to ask numpy questions on the numpy mailing list.

   http://www.scipy.org/Mailing_Lists

> I'd like to compute an FFT on an array of numbers but I can't
> seem to access the FFT function.  I'm fairly new to Python (obviously)
> and I can't seem to find documentation to match my distribution of
> numpy and I can't figure out how to access the FFT function.
> 
> Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit
> (Intel)] on win32
> Type "copyright", "credits" or "license()" for more information.
> 
> IDLE 1.2
>>>> from numpy import *
>>>> a=array((1,2,3,2,1,2,3,2,1))
>>>> fft(a)
> 
> Traceback (most recent call last):
>   File "<pyshell#2>", line 1, in <module>
>     fft(a)
> TypeError: 'module' object is not callable

All of the fft functions are in the numpy.fft module.

 >>> from numpy import *
 >>> a=array((1,2,3,2,1,2,3,2,1))
 >>> fft.fft(a)
array([  1.70000000e+01+0.j        ,  -1.15270364e+00-0.41954982j,
         -3.37938524e+00-2.83564091j,   5.00000000e-01+0.8660254j ,
          3.20888862e-02+0.18198512j,   3.20888862e-02-0.18198512j,
          5.00000000e-01-0.8660254j ,  -3.37938524e+00+2.83564091j,
         -1.15270364e+00+0.41954982j])

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco




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