Complex arg-trig functions

[Bruce Evans]

On Sat, 22 Sep 2012, Stephen Montgomery-Smith wrote:

> 1. Your recent optimizations seem to have given an overall 3% time saving in 
> my timing tests.  That's pretty good in my opinion.

Hopefully more for large and small args :-).

> 2.  In my accuracy tests for casin(h), I have never seen the double or long 
> double have an error greater than 4 ULP.  But for the float case I have seen 
> 4.15 ULP.

I haven't seen any larger than 3.4.  What is the worst case you found?
Errors found for float precision tend to be because the density of bad
cases is higher so it is easier to test more of them accidentally.  I
did do some non-random testing for all float cases in narrow strips
about x or y = 0 or 1, but not for all combinations of this with all
functions.

Bruce