#avr Logs

Apr 16 2022

12:33 AM nonlinear is now known as zero-xray
05:37 PM rue_mohr: WormFood, in 1967, the kooley-tukey fft alg (the one we all use now) was written in fourth
05:37 PM rue_mohr: WTF were they running it on, and WTF data were they feeding into it!?
05:37 PM rue_mohr: http://ruemohr.org/~ircjunk/programming/FOUR1.txt
05:38 PM rue_mohr: and no, you CANT get the IEEE document because IEEE broke it up into pages and sells each page individually
05:39 PM rue_mohr: "PROGRAMS FOUR2 AND FOURT ARE AVAILABLE THAT RUN
05:39 PM rue_mohr: C TWICE AS FAST AND OPERATE ON MULTIDIMENSIONAL ARRAYS WHOSE
05:39 PM rue_mohr: C DIMENSIONS ARE NOT RESTRICTED TO POWERS OR TWO."
05:39 PM rue_mohr: BUT, THIS code was easy to port because its was small,
05:39 PM rue_mohr: so, to this day, we use it
05:39 PM rue_mohr: it was ported from fourth to BASIC, then to C, then to C++ and everything else
05:40 PM rue_mohr: nobody ever actually understood it, so they didn't fix anything
05:40 PM rue_mohr: you see, fourth has no bitwise operateors
05:40 PM rue_mohr: so alot of the acrobatics in that code, are just doing bitwise operations in regular math
05:41 PM rue_mohr: its absolutely amazing when you tear it apart
05:41 PM rue_mohr: I got the code from a bad scan of a document off a military ftp site
05:42 PM rue_mohr: what I love, and find halarious, is that this code has been ported and hacked a million times since it was written
05:42 PM rue_mohr: BUT, from the comments, it, itself, is a hack
05:43 PM rue_mohr: its a mash up of cooley and tukeys code
05:43 PM rue_mohr: :)
05:43 PM rue_mohr: its a hack
05:43 PM rue_mohr: from 1967
06:12 PM josuah: FAST ROURIER TRANSFORM, this seems ubiquitous
06:12 PM josuah: rue_mohr: can I publish this story in a tiny online newspaper?
06:14 PM josuah: regardless, that is quite terryfing to imagine an as efficient as possible workaround around a lack of bitwis operations... is be used as a bible and preciously preserved since that long!
06:16 PM josuah: I am also much surprised by the behavior of most standardisation organisation making standards paid for $$$$
06:19 PM josuah: is that classified by any chance? :P
06:42 PM qu1j0t3: rue_mohr: You mean Fortran :)
06:42 PM qu1j0t3: josuah: Not in the least, Cooley-Tukey was published in the literature
06:42 PM * qu1j0t3 used it in the 80s
06:42 PM * qu1j0t3 briefly. for generation of 2d fractal noise
06:42 PM qu1j0t3: at that time I used a C version)
07:37 PM WormFood: rue_mohr, what is "fourth"? I never heard of that before.
07:42 PM qu1j0t3: it's Fortran........
07:42 PM qu1j0t3: rue might have been thinking of Forth
07:42 PM WormFood: I think so ;)
07:43 PM WormFood: "forth" does not need "u" ;)
08:33 PM specing_ is now known as specing
09:13 PM nonlinear is now known as zero-xrayt
09:13 PM zero-xrayt is now known as zero-xray