Re: [Algorithms] approximation to pow(n,x)?

[Danny K. <dr...@we...>]

 >  x^m = exp(m log x)
> 
> 
> So really you need a fast exp and log function.
> 
> 
> Can you newton-raphson refine a log and exp calculation?  
> I've never tried ... perhaps someone else can help there.
> 
> 
> Failing that you could probably use tables for the 
> calculations though this, obviously, limits the range of 
> powers you can perform.

I know nothing about this but one thing that pops into my head is that exp
and log both have a lot of self-similarity features so I wonder whether that
would help.

I once experimented with using a look-up table with very few entries and
catmull-rom interpolation between them. It was just playing, but I do
remember getting surprisingly fast results on sin and cos.

Danny (aware he's out of his depth...)