9 Apr
2014
9 Apr
'14
6:37 p.m.
Dear Vladimir,
You formula does not work for abs(f) and complex values. I have proposed here
http://www.ginac.de/pipermail/ginac-devel/2013-November/002053.html
another formula:
(abs(f))'=(f'*f.conjugate()+f*f'.conjugate())/2/abs(f)
It requires some revision of function class and new method of derivation going beyond the chain rule. I proposed to do this job, but do not remember my email to be answered.
Best wishes, Vladimir -- I hadn't thought of complex numbers, but then I'm not much of a mathematician anyway.
About the responsiveness of the list, I made the same experience. A while ago I volunteered to contribute some code, but nobody ever answered to my suggestions. Greetings, Jan