Hackers 
they are when it comes to math 
Would subtraction also approximate division?
Yes.
Would negation also approximate the reciprocal?
I've always hated that it's called an "inverse". It's not an inverse. The inverse of square root is square. If they had called it "reciprocal", it would have been clear to me what it does, but "inverse" confused the heck out of me when I first saw it.
It's confusing for non-mathematicians, but (and you may know that) it is not incorrect. https://en.wikipedia.org/wiki/Inverse_element "In mathematics, the concept of an inverse element generalises the concepts of opposite (βx) and reciprocal (1/x) of numbers."
Shoulda just called it fast 
mapping()
"inverse" has a very specific meaning: inverse(x) * x = 1, x^2 * x != 1 for any x other than 1. So no, x^2 is not the inverse of sqrt(x)
The inverse is about the negative power right? Square root is the 0.5
Jump in the discussion.
No email address required.
was he actually trying to say "square root is the 0.5 exponent," i.e. the inverse of x^2=y is y^(0.5)=x
Jump in the discussion.
No email address required.
The comment chain is about whether fastInverseSqrt(x) = 1/sqrt(x) = x^(-0.5) should be called fastReciprocalSqrt(x).
With his logic, fastInverseSqrt could just as well mean -x^0.5
Jump in the discussion.
No email address required.
just throw an i in there or something
Jump in the discussion.
No email address required.
More options
Context
More options
Context
More options
Context