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This is a link post For anyone who has found themselves using C for bit-fiddling
here's a neat explanation of a fast approximation to an inverse square root function found in the Quake 3 engine.

For everyone else it's a good insight into some of the mathematical methods used in Comp Sci.
(I helped save b3ta! wheresthefish Partly filled with wrong, Fri 5 Mar 2021, 19:31, , Reply)
This is a normal post just read that as 'a good night in with mathematical methods used in compsci'

(Mehitabel_Itrang, Fri 5 Mar 2021, 20:01, , Reply)
This is a normal post That too

(I helped save b3ta! wheresthefish Partly filled with wrong, Fri 5 Mar 2021, 20:25, , Reply)
This is a normal post Bitophiles

(I helped save b3ta! FeralCatMan Unusual disease collector., Fri 5 Mar 2021, 21:47, , Reply)
This is a normal post And Creative decided to sue him.
Oh, how we laughed.
 (I helped save b3ta! jonbob loves you, Fri 5 Mar 2021, 23:13, , Reply)
This is a normal post this explains why I always just miss in quake. Goddamn approximated vectors...

(I helped save b3ta! cumquat may will not be commenting further on the allegations, Sat 6 Mar 2021, 0:02, , Reply)
This is a normal post i liked that
but if i've ever seen a bit of code that actually needs an insightful comment, it's that.
 (horrid, Sat 6 Mar 2021, 11:20, , Reply)
This is a normal post I've not had time to watch that yet
But I'm confused about the meaning of a function called an "inverse square root".
 (Papagato RackSpanner, Sat 6 Mar 2021, 13:35, , Reply)
This is a normal post They mean x -> 1 / sqrt(x)

(Pie of Meat ___°¬¯O¯____\o/_____/\_,____Y¯¯Y, Sat 6 Mar 2021, 15:24, , Reply)
This is a normal post squirt

(I helped save b3ta! FeralCatMan Unusual disease collector., Sat 6 Mar 2021, 21:42, , Reply)
This is a normal post Yeah it's really reciprocal-square-root.

(eViLegion Chief Commissioner of the Scottish Lunacy Board, Sun 7 Mar 2021, 12:56, , Reply)
This is a normal post in the cubic forest, by the roundabout, I didst find a square root, but couldn't work it out
that's an inverse square root
 (I helped save b3ta! cumquat may will not be commenting further on the allegations, Mon 8 Mar 2021, 5:47, , Reply)
This is a normal post badum
tish
 (ozof, Mon 8 Mar 2021, 10:41, , Reply)
This is a normal post Mostly, this just put me in my place
Though everybody thought I was a brilliant programmer in my day
 (strongp, Sat 6 Mar 2021, 19:37, , Reply)
This is a normal post esoteric stuff like this is rarely needed though
Even possibly detrimental in some contexts.

When it is needed though, like here, it's brilliant.
 (horrid, Sun 7 Mar 2021, 0:00, , Reply)
This is a normal post This method is fun!
The MD software GROMACS has a similar method but uses a look-up tables to provide the initial guess. This allows computation of 1/sqrt(r) to 32 bit accuracy with a single Newton iteration.
 (emptyspace, Mon 8 Mar 2021, 10:06, , Reply)