Complex arg-trig functions

[Stephen Montgomery-Smith]

I will be posting my updates on this web page:

http://people.freebsd.org/~stephen/

The file catrig.c contains implementations of cacos(h), casin(h), 
catan(h).  I have been working on it everyday - I seem unable to put it 
down.

I have now tested the following values for x and y:
1. Random values normally distributed N(0,1)
2. Random values e^X where X is uniformly distributed on [-300,300]
3. Random values 1+e^x or -1+e^x where X is uniformly distributed on 
[-20,0].
4. Combinations from (2) and (3).

The worst case errors seem to be below 4 ULP.

It passes Peter Jeremy's program http://www.rulingia.com/~peter/ctest.c 
for checking edge cases like inf, nan, -0 etc.

I am looking for suggestions:

1.  For the implementations - improvements to the program to make it 
more accurate.
2.  Other ranges of values to test for.
3.  And yes, I am now ready at accept changes to the writing style.

Thanks, Stephen