numpy-discussion

[Numpy-discussion] fftshift

[Cliff M. <cam...@sn...>]

All,

First I'd like to thank Paul Dubois, Todd Miller and Perry Greenfield 
for the help you gave me on setting defined values based on index values 
in an array.  Your fixes worked and let me get done what was needed.

This leads me to my second problem.  In Matlab there is a function 
called fftshift that lets one shift the fft values for more easy 
visualization.  Numeric doesn't seem to have a function like that 
explicitly although I suppose one could use the flip function in the 
MatPy module.  Has anyone implemented something like the fftshift 
function or could you suggest the best way to do this?  Thanks for your 
help.  Oh I'm doing this on a 2D array.

Cliff Martin

Re: [Numpy-discussion] fftshift

[Pearu P. <pe...@ce...>]

On Thu, 29 May 2003, Cliff Martin wrote:

> This leads me to my second problem.  In Matlab there is a function 
> called fftshift that lets one shift the fft values for more easy 
> visualization.  Numeric doesn't seem to have a function like that 
> explicitly although I suppose one could use the flip function in the 
> MatPy module.  Has anyone implemented something like the fftshift 
> function or could you suggest the best way to do this?  Thanks for your 
> help.  Oh I'm doing this on a 2D array.

scipy.fftpack has fftshift. If you don't care building scipy
yourself then the implementation of fftshift can be viewed via
CVSview at www.scipy.org, look at the file
  scipy/Lib/fftpack/helper.py

HTH,
	Pearu