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Re: 2D FFT Slow. Any ideas? [message #37250 is a reply to message #37249]

Fri, 05 December 2003 10:04

R.G. Stockwell
Messages: 363
Registered: July 1999

Senior Member

"Brian" <brian.huether@NOdlrSPAM.de> wrote in message
news:a298a85e9af4e70d51199dcae50c4c81@news.teranews.com...
> I did a little benchmark between IDL and MATLAB. In each case I created a
> random double precision complex array of size 2048 by 2048 and timed how
> long the 2D FFT took. In MATLAB 6.5 it took about 3.5 sec, and in IDL, it
> took about 10 sec. Is there a way to have IDL use MATLAB for the FFT,
> perhaps using activex? Or would the overhead in using activex defeat the
> purpose?
>
> thanks,
>
> brian
>
>

You could try calling an external routine, some of the best being available
at (fastest ft in the west)

http://fftw.org/

Cheers,
bob

PS I can't believe active x calls would improve speed, but hey, you never
know.
And, I'm surprised that the canned IDL is not very fast. Any chance you
don't really
have a 2048^2 array in idl (did you make a 2049^2 array for instance?)

If you post a blip of example code, I can run them here (matlab and idl) and
verify the time difference,
which would be very interesting.

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[Message index]

		Re: 2D FFT Slow. Any ideas? By: Brian on Mon, 08 December 2003 00:02
		Re: 2D FFT Slow. Any ideas? By: R.G. Stockwell on Fri, 05 December 2003 13:05
		Re: 2D FFT Slow. Any ideas? By: K. Bowman on Fri, 05 December 2003 10:32
		Re: 2D FFT Slow. Any ideas? By: R.G. Stockwell on Fri, 05 December 2003 10:04
		Re: 2D FFT Slow. Any ideas? By: Richard French on Mon, 08 December 2003 12:17

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