Faster FFT...off topic but relevant

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Faster FFT...off topic but relevant

John Ragle
Does anyone know any details about the "new" ultra-fast Katabi FFT, its
coding, etc. as reported in the most recent New Scientist?

John Ragle -- W1ZI

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Re: Faster FFT...off topic but relevant

Mike WA8BXN
Is this what you are looking for?
http://arxiv.org/pdf/1201.2501v1.pdf 
 
73 - Mike WA8BXN
 
 
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Re: Faster FFT...off topic but relevant

Jessie Oberreuter-2
In reply to this post by John Ragle

      I only glanced at the academic paper when it went by a few weeks ago,
but IIRC, it offers improved performance for low [dominant] information
content samples.  It's been 15+ years since I did the math, but I thought
the original function series did this well.  The FFT optimizations,
however, don't -- rather like the way it's often faster to compute
multiple results and throw away the ones you don't need, than it is to
make constant culling decisions along the way.  Thus, I looked at the
paper, said to myself, "this may be a good tool when I'm trying to save
battery power or when I know that I only need to identify a small number
strong signals, but it isn't going to change the world" and moved on :).
-kb7psg



On Tue, 31 Jan 2012, John Ragle wrote:

> Does anyone know any details about the "new" ultra-fast Katabi FFT, its
> coding, etc. as reported in the most recent New Scientist?
>
> John Ragle -- W1ZI
>
> --
> Sent from my lovely old Dell XPS 420
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
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Re: Faster FFT...off topic but relevant

Jessie Oberreuter-2

      I should note that it didn't catch my interest because the domains
/I/ generally throw FFTs against contain large numbers of signals with a
lot of dynamic range between them, and I really do need most of the data.
OTOH, there are almost certainly a HUGE number of domains for which
faster/cheaper isolation of the top k signals would be a big win.
      The most common "break throughs" I see in industry occur when a fresh
pair of eyes looks at a problem and says, "wait, you're using the wrong
approach -- there's a much better tool for this case".  Nine out of ten,
it's also either been around for 50+ years and has just been forgotten, or
it's just far enough out of the domain that most of the folks on the job
were never exposed to it.  Thus, /knowing/ that something like this exists
and the kinds of probglems it is good for is far more important than
trying to brute force apply it to every problem.  -kb7psg


On Tue, 31 Jan 2012, Jessie Oberreuter wrote:

>
>      I only glanced at the academic paper when it went by a few weeks ago,
> but IIRC, it offers improved performance for low [dominant] information
> content samples.  It's been 15+ years since I did the math, but I thought
> the original function series did this well.  The FFT optimizations,
> however, don't -- rather like the way it's often faster to compute
> multiple results and throw away the ones you don't need, than it is to
> make constant culling decisions along the way.  Thus, I looked at the
> paper, said to myself, "this may be a good tool when I'm trying to save
> battery power or when I know that I only need to identify a small number
> strong signals, but it isn't going to change the world" and moved on :).
> -kb7psg
>
>
>
> On Tue, 31 Jan 2012, John Ragle wrote:
>
>> Does anyone know any details about the "new" ultra-fast Katabi FFT, its
>> coding, etc. as reported in the most recent New Scientist?
>>
>> John Ragle -- W1ZI
>>
>> --
>> Sent from my lovely old Dell XPS 420
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Re: Faster FFT...off topic but relevant

Tony Estep
On Tue, Jan 31, 2012 at 2:32 PM, Jessie Oberreuter
<[hidden email]> wrote:
>... it isn't going to change the world...
============
I remember about 30 years ago when the Karmarkar algorithm for linear
optimization appeared. On certain problems, it appeared that it would
be about 10x as fast as conventional schemes. At the place I was
working we were doing lots of big linear problems involving bond
portfolios, and we got all excited. One of the guys laboriously wrote
code to implement it, only to discover that on our kind of problems,
the plain-vanilla simplex approach we had been using was about 10x
faster than the new fancy one.

Tony KT0NY



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Re: Faster FFT...off topic but relevant

Charles Buse
In reply to this post by John Ragle
You can download the original MIT paper from
http://arxiv.org/abs/1201.2501v1.

On 31 Jan 2012 20:18, John Ragle wrote:
> Does anyone know any details about the "new" ultra-fast Katabi FFT, its
> coding, etc. as reported in the most recent New Scientist?
>
> John Ragle -- W1ZI
>

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