comp.lang.idl-pvwave archive: archive » Re: Doing a DFT in IDL

Home » Public Forums » archive » Re: Doing a DFT in IDL

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

Re: Doing a DFT in IDL [message #79776 is a reply to message #79773]

Mon, 02 April 2012 14:24

Kenneth P. Bowman
Messages: 585
Registered: May 2000

Senior Member

In article < 22647522.376.1333369882343.JavaMail.geo-discussion-forums@yn gr3 >,
Helder <helder@marchetto.de> wrote:

> Dear all,
> I've been looking for this around, but couldn't yet find anything.
> I would like to made a (discrete) Fourier transform by directly typing in the
> code. The target is not performance, but eventually modifying the source
> (integrated) function from [f(x)exp(-j2piux/N)] to something different.
> Has anybody written such a code in IDL that can be modified? Or can anybody
> give me a working link to such a code?
>
> Many thanks and sorry for wasting your time.
> Cheers, Helder

A DFT is just a set of dot products. (And an FFT is an efficient way to
carry out the DFT calculations.)

Compute the basis functions that you want at the tabulated points,
then multiply by the function you are transforming and sum.
You can write it as a matrix-vector multiplication.

Ken Bowman

Report message to a moderator

[Message index]

		Re: Doing a DFT in IDL By: Helder Marchetto on Tue, 03 April 2012 02:23
		Re: Doing a DFT in IDL By: Helder Marchetto on Tue, 03 April 2012 02:21
		Re: Doing a DFT in IDL By: Kenneth P. Bowman on Mon, 02 April 2012 14:24
		Re: Doing a DFT in IDL By: Russell[1] on Mon, 02 April 2012 07:19

Previous Topic:	modify colors in contour plots
Next Topic:	Coyote Graphics Raster File Output

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 14:56:40 PDT 2025

Total time taken to generate the page: 0.80032 seconds