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Old 11-27-2007, 06:35 PM
Chris Bore
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Default 2D FFT expected time?

What time would one expect for a 32x32 2D FFT (complex, double
precision), on a 'modern' PC?

Is a time of 2 seconds in any way reasonable?

(The time is for a program that seems to be written for .NET using
C#).

Thanks,

Chris
====================
Chris Bore
BORES Signal Processing
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  #2 (permalink)  
Old 11-27-2007, 06:44 PM
Tim Wescott
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Default Re: 2D FFT expected time?

On Tue, 27 Nov 2007 09:35:17 -0800, Chris Bore wrote:

> What time would one expect for a 32x32 2D FFT (complex, double
> precision), on a 'modern' PC?
>
> Is a time of 2 seconds in any way reasonable?
>
> (The time is for a program that seems to be written for .NET using
> C#).
>
> Thanks,
>
> Chris
> ====================
> Chris Bore
> BORES Signal Processing


In Scilab, a 32 x 32 FFT took less time that the computer could say "Bob's
yer Uncle" (it reported 1ms, but that's at the limit of it's range).

A 256 x 256 took 25ms, and a 1024 x 1024 (after increasing the stack size)
took 626ms.

Take it from there...

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
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  #3 (permalink)  
Old 11-27-2007, 06:49 PM
Vladimir Vassilevsky
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Default Re: 2D FFT expected time?



Chris Bore wrote:

> What time would one expect for a 32x32 2D FFT (complex, double
> precision), on a 'modern' PC?
>
> Is a time of 2 seconds in any way reasonable?


Absolutely unreasonable. It should be at the order of millisecond.

> (The time is for a program that seems to be written for .NET using
> C#).


The smart programming, especially using the interpreters, can produce
the miraculous results.

Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
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  #4 (permalink)  
Old 11-27-2007, 09:55 PM
Jerry Avins
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Default Re: 2D FFT expected time?

Chris Bore wrote:
> What time would one expect for a 32x32 2D FFT (complex, double
> precision), on a 'modern' PC?
>
> Is a time of 2 seconds in any way reasonable?
>
> (The time is for a program that seems to be written for .NET using
> C#).


No way. How much spam did the 'modern' PC spew out over the internet
while it was ostensibly working on the problem?

Jerry
--
Engineering is the art of making what you want from things you can get.
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
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