Martin D Kealey wrote: > On Thu, 26 Feb 2009, Jon Lang wrote: >> asin is not the inverse function of sin, although it's probably as close >> as you can get. And even there, some sort of compiler optimization could >> potentially be done, replacing the composition of asin and sin (both of >> which have the potential to intensify error) with a normalization of the >> value into the -pi ..^ pi range (which might also introduce error). > > Hmmm ... the normal mathematical range of arc-sine is (-π,+π], rather than > [-π,+π), especially where complex numbers are concerned: arg(-1) == +π. > (Well, so much for consistently using lower half-open ranges.)
...you're right. Sorry; my error. -- Jonathan "Dataweaver" Lang