comp.lang.idl-pvwave archive: archive » Re: how do you zero-pad FFTs in IDL?

Home » Public Forums » archive » Re: how do you zero-pad FFTs in IDL?

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: how do you zero-pad FFTs in IDL? [message #9302]

Wed, 25 June 1997 00:00

Amara Graps
Messages: 24
Registered: June 1996

Junior Member

Paul Woodford wrote:
>
> Is there a quick method to zero-pad an FFT in IDL? For example,
> in matlab you can write fft(x,256) to zero-pad the FFT to 256
> elements.

I don't know of a quick way, but this will work to pad an array to
the next 2^n length: (I would be interested in even shorter
ways.. anybody?)

x = findgen(1000) ;want to zero-pad this to 1024 length
n_work=2L^(fix(alog(n_elements(x))/alog(2))+1)
pad=fltarr(n_work-n_elements(x))
x = [x,pad]

Then FFT the x array.

Amara

--

************************************************************ **
Amara Graps amara@quake.stanford.edu
Solar Oscillation Investigations Stanford University
http://quake.stanford.edu/~amara/
************************************************************ **
"Never fight an inanimate object." - P. J. O'Rourke

Report message to a moderator

[Message index]

Re: how do you zero-pad FFTs in IDL?

By: Amara Graps on Wed, 25 June 1997 00:00

Previous Topic:	How to read MJPEG files into IDL
Next Topic:	displaying true color tiff

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 29 15:50:16 PDT 2025

Total time taken to generate the page: 2.59733 seconds