Matt Giwer wrote:

> "Greg M. Johnson" wrote:
> > what is x^a?
>     x to the power a or exp( a * log(x) )
>     If a = 2 then it would be x*x

Nope.  You cannot take the ln(x) of a negative x! Therefore, that's NOT what povray
is doing!  My guess is

x^a= sign(x)^int(a)* abs(x)^a .

My re-writing of the function is "defined" for all values of x and a, whereas x^a is
NOT.

Again, I hound this point not to attack the giants whose shoulder we stand on--pov
developers--but to have fun at solving a mathematical mystery : what IS pov doing?

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