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A comment on Revisiting the Fast Inverse Square Root – Is It Still Useful?. Parent comment

Re:Revisiting the Fast Inverse Square Root – Is It Still Use... by adgjlsfhk1 on Friday April 21, 2023 @12:56AM (#35649946)
polynomials are still king. a 6th degree polynomial is often enough and will be faster than a 2nd degree rational.
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Re:Revisiting the Fast Inverse Square Root – Is It Still Use... by pclmulqdq on Friday April 21, 2023 @07:46AM (#35652366)
A 6th degree polynomial is firmly in the "fast approximation" category. I think sin/cos are ~15th degree polynomials for 1 ULP of precision.
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Re:Revisiting the Fast Inverse Square Root – Is It Still Use... by moonchild on Friday April 21, 2023 @08:00AM (#35652459)
https://github.com/rutgers-apl/The-RLIBM-Project/blob/main/l... has a lot less and claims to be correctly rounded.
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Re:Revisiting the Fast Inverse Square Root – Is It Still Use... by pclmulqdq on Friday April 21, 2023 @08:12AM (#35652558)
For 32-bit float, yes. For double precision, not so much.
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Re:Revisiting the Fast Inverse Square Root – Is It Still Use... by adgjlsfhk1 on Friday April 21, 2023 @01:09PM (#35656858)
sin/cos commonly use 2 different 5th degree polynomials (depending on quadrant of the sin graph) https://github.com/JuliaLang/julia/blob/bb83df1d61fb649efd15...
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