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Re: 2D FFT Slow. Any ideas? fft2() [message #37245 is a reply to message #37233]

Fri, 05 December 2003 13:13

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

Senior Member

"R.G. Stockwell" <noemail@please.com> wrote in message
news:wq6Ab.409$v23.28199@news.uswest.net...
>
> Hi Brian,
> I found some time to take a look at this, and I see the same thing you do.
> This is on a 1.13 ghz dell inspiron 8100 laptop running win2000.
> Matlab 6.5 did the fft of 2048 by 2048 array of doubles in 0.9 seconds.
> IDL 6.0 did it in 4.6 seconds (ram 109 MBs).
>
> Wow, that is surprising. The idl version is quite slow.
>
> For a double complex array IDL takes 8.1 seconds (ram 174 MBs),
> matlab takes 1.6 sec (211 mb ram).
>
> Interesting.
>
> -bob

DOH!

Um.... after I posted this, I realized that one should use fft2() in
matlab.

The matlab time for the fft of a double 2048 by 2048 is 3.2 seconds.

So, it is in line with the IDL times, and IDL seems to handle memory a
little
more efficiently.

Cheers,
bob

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[Message index]

		Re: 2D FFT Slow. Any ideas? fft2() By: Richard French on Mon, 08 December 2003 11:33
		Re: 2D FFT Slow. Any ideas? fft2() By: mmiller3 on Mon, 08 December 2003 06:44
		Re: 2D FFT Slow. Any ideas? fft2() By: Brian on Mon, 08 December 2003 00:06
		Re: 2D FFT Slow. Any ideas? fft2() By: R.G. Stockwell on Fri, 05 December 2003 13:13
		Re: 2D FFT Slow. Any ideas? fft2() By: h_chapman on Sat, 13 December 2003 21:58

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