Talk:Rader's FFT algorithm: Difference between revisions

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Latest revision as of 10:35, 23 May 2024

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{{WikiProject Computing |importance=Low |science=y |science-importance=Low |software=y |software-importance=Low}}

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Hey, does anyone have a ___location for where this conference took place. The citation reads:

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but I don't see a ___location.

:''Proceedings of the IEEE'' is a journal, not a conference. See [http://www.ieee.org/portal/pages/pubs/proceedings/index.html;jsessionid=GR7JknHqhZcnKKysvQJyqJsDJMyGfJvLw6dDgJSrH6pbTDXdzPQ2!770082833 here]. [[User:Stevenj|—Steven G. Johnson]] 21:54, 2 April 2007 (UTC)

== Finding the generator (g) ==

The algorithm explained in the article uses a generator - g - of the modulo N multiplication group, known to exist from number theory. However, no algorithmic way is mentioned to find such a generator. Is there an efficient way to do this? [[Special:Contributions/2A02:8109:9340:112C:FD62:EAA0:5CCE:62F8|2A02:8109:9340:112C:FD62:EAA0:5CCE:62F8]] ([[User talk:2A02:8109:9340:112C:FD62:EAA0:5CCE:62F8|talk]]) 01:01, 9 February 2015 (UTC)

:Since the generators are extremely common, just exhaustive testing will turn one up pretty quickly, although there are slightly faster algorithms than this. (See e.g. Donald E. Knuth, ''The Art of Computer Programming, vol. 2: Seminumerical Algorithms'', 3rd edition, section 4.5.4, p. 391 (Addison–Wesley, 1998).) I'll add a link. (It's also discussed in [[Primitive root modulo n#Finding primitive roots]].) [[User:Stevenj|— Steven G. Johnson]] ([[User talk:Stevenj|talk]]) 18:03, 24 October 2017 (UTC)

== So who is "Rader"? ==

This article isn't very clear who the "Rader" in question is. If it's Rader's FFT algorithm, then it should say who it was named after.--[[User:Varkman|Varkman]] ([[User talk:Varkman|talk]]) 05:16, 20 November 2015 (UTC)

:Note that this has been fixed (it is Charles M. Rader, a well-known figure in the signal-processing community). [[User:Stevenj|— Steven G. Johnson]] ([[User talk:Stevenj|talk]]) 17:52, 24 October 2017 (UTC)

== Time complexity without zero-padding ==

Without zero-padding, the article states that the worst case requires O(N²) time. But each step of the recursion halves N, therefore isn't it still O(N log N) time? <!-- Template:Unsigned --><span class="autosigned" style="font-size:85%;">—&nbsp;Preceding [[Wikipedia:Signatures|unsigned]] comment added by [[User:Raysphere24|Raysphere24]] ([[User talk:Raysphere24#top|talk]] • [[Special:Contributions/Raysphere24|contribs]]) 08:18, 3 January 2021 (UTC)</span> <!--Autosigned by SineBot-->

:Agree. [[Special:Contributions/128.54.13.249|128.54.13.249]] ([[User talk:128.54.13.249|talk]]) 22:14, 9 November 2023 (UTC)

:Agree as well. I see no O(n²⁾ runtime. [[Special:Contributions/2A02:1210:2657:D600:63B7:3ED2:BBA4:60D3|2A02:1210:2657:D600:63B7:3ED2:BBA4:60D3]] ([[User talk:2A02:1210:2657:D600:63B7:3ED2:BBA4:60D3|talk]]) 10:35, 23 May 2024 (UTC)