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Faster Fourier transform among world’s most important emerging technology

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21–30 of 49 posts

Re: Faster Fourier transform among world’s most important emerging technology

#21
post #5

Paper at: http://arxiv.org/abs/1201.2501v1 O(k log n log(n/k)) complexity for the general case.

I thought normally k=n, and the ordinary complexity is O(n log(n)). So this sounds worse for the normal case.

I guess if you use a smaller k it is useful.

Re: Faster Fourier transform among world’s most important emerging technology

#22
Disagree. I think that natural scrolling gestures in Mac OS Lion is more revolutionary and more intuitive to use than this "faster Fourier transform". That technology sounds like it only used by nerds, and I'm sure it has a TERRIBLE user experience.

Re: Faster Fourier transform among world’s most important emerging technology

#23
post #17

they make this seem like a huge deal, anyone know why? is this going to like put HD content on an iPhone? I don't expect that the signal processing hardware is the bottleneck here.

> I don't expect that the signal processing hardware is the bottleneck here. Computational resources is always the bottleneck in bioinformatics, quantum chemistry, or any sort of high data volume analysis or simulation, and the FFT is a fundamental and commonly used transform in all fields. At least for people who still use computers to, well, compute things, a faster FFT is a huge deal.

>At least for people who still use computers to, well, compute things, a faster FFT is a huge deal.

This is a useless post except that I wanted to highlight that wonderful little bon mot. Well done.

Re: Faster Fourier transform among world’s most important emerging technology

#24
post #15
post #8

Awesome. It'll sure be nifty when 2029 rolls around and the patent expires, so applications can actually use the algorithm. (No, I don't have any information that an sFFT patent has been filed, but this would be standard practice at MIT). Tornado/fountain codes are a similar case. Pardon my bitterness, but it's an interesting question to wonder whether, by funding researchers to invent algorithms of this type and loc…

Algorithms and mathematical methods are not supposed to be patentable in the US.

No problem, just find a way to implement the algorithm which doesn't violate at least one of at least 121 "fast fourier transform" pattents and you're all set (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sec...). Just repeat that process for every algorithm you might want to implement and you'll have no problem writing software.

Re: Faster Fourier transform among world’s most important emerging technology

#25

Disagree. I think that natural scrolling gestures in Mac OS Lion is more revolutionary and more intuitive to use than this "faster Fourier transform". That technology sounds like it only used by nerds, and I'm sure it has a TERRIBLE user experience.

I'd recommended giving the article another read.

Re: Faster Fourier transform among world’s most important emerging technology

#26
post #21
post #5

Paper at: http://arxiv.org/abs/1201.2501v1 O(k log n log(n/k)) complexity for the general case.

I thought normally k=n, and the ordinary complexity is O(n log(n)). So this sounds worse for the normal case. I guess if you use a smaller k it is useful.

Most signals you get by sampling real world objects will be fairly sparse. You can expect anywhere between 50% and 95% of the coefficients in a wavelet or fourier domain to be near zero depending on the class of signal.

However, be wary of algorithms that expect K as input, as they are asking you to classify your signal before analysis.

Re: Faster Fourier transform among world’s most important emerging technology

#27
post #15
post #8

Awesome. It'll sure be nifty when 2029 rolls around and the patent expires, so applications can actually use the algorithm. (No, I don't have any information that an sFFT patent has been filed, but this would be standard practice at MIT). Tornado/fountain codes are a similar case. Pardon my bitterness, but it's an interesting question to wonder whether, by funding researchers to invent algorithms of this type and loc…

Algorithms and mathematical methods are not supposed to be patentable in the US.

And yet, we've had plenty of software patents which have held up in court and caused significant damage to companies which were found to be infringing, and many more which have backed off due to fear of the same.

Mathematical facts aren't patentable. That much has been established. Perhaps a "pure" algorithm isn't patentable; but all software patents start out with something like "a general purpose computer which...", tying it to hardware and making it patentable. Good luck implementing that algorithm without a general purpose computer.

For instance, the i4i patent is a patent purely on an algorithm, and Microsoft lost that case and had to remove the feature from its software: http://en.swpat.org/wiki/I4i_v._Microsoft . I'm not sure how you can square that with algorithms not being patentable.

Re: Faster Fourier transform among world’s most important emerging technology

#28
post #15
post #8

Awesome. It'll sure be nifty when 2029 rolls around and the patent expires, so applications can actually use the algorithm. (No, I don't have any information that an sFFT patent has been filed, but this would be standard practice at MIT). Tornado/fountain codes are a similar case. Pardon my bitterness, but it's an interesting question to wonder whether, by funding researchers to invent algorithms of this type and loc…

Algorithms and mathematical methods are not supposed to be patentable in the US.

As a famous American statesman once put it: "Justice Marshall has made his decision - now let him enforce it."

It's commonly supposed that the Supreme Court could void these illegal patents - could dissolve this entire illegal industry - with a swish of their shiny polyester robes. Actually they already tried that, in Flook. Jedi mind tricks, which in the end is all the Court really has, worked about as well on Andrew Jackson.

I think this explains the disappointing result of Bilski. If you are supposed to have a magic power which in reality doesn't exist, make every excuse to avoid using it. You may still be suspected of impotence, but at least the suspicion is not confirmed.

Unfortunately there isn't really a solution to the patent problem that's compatible with the rule of law, mostly because the rule of law was so long ago abandoned for the rule of lawyers. Perhaps Andrew Jackson could round them all up and march them to Oklahoma - or at least, Marshall, Texas.

Re: Faster Fourier transform among world’s most important emerging technology

#29
post #3

Does this mean real-time Dirac video encoding might be possible?

No, Dirac is based on wavelet transforms, which have different math behind them, not using Fourier transforms. This Sparse Fourier Transform (which the authors are now calling the sFFT) would be more useful for traditional FFT/DCT compression algorithms. Though for the most part, the hardware for even very complicated real-time Fourier-based compression (H.264, HD) already exists.

The other observation I make is that apart from their computational complexity, FFTs work well in hardware because they have reasonably efficient implementations.

Implementation of an FFT on a chip has two components: the logic/computing elements ( governed by O(n.log(n)) ) and the routing of signals between those elements. It turns out the size and speed of the FFT is mainly determined by the routing, not by the logic, and there is a tractable routing solution to a reasonable number of points [1]. The computation complexity becomes secondary if the complexity of the implementation is determined by the non-computational aspects.

[1] Based on experience in 1995.

Re: Faster Fourier transform among world’s most important emerging technology

#30
post #8

Awesome. It'll sure be nifty when 2029 rolls around and the patent expires, so applications can actually use the algorithm. (No, I don't have any information that an sFFT patent has been filed, but this would be standard practice at MIT). Tornado/fountain codes are a similar case. Pardon my bitterness, but it's an interesting question to wonder whether, by funding researchers to invent algorithms of this type and loc…

That's only true for the US. In the majority of other countries algorithms aren't patentable.
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