Re: [Bug-libmatheval] derivatives vs new functions

[Giulio Bottazzi]

Hello,
I find the derivative functionality quite useful, to say the truth. I
used it extensively in the recent code I wrote. Can I suggest, instead
of removing this feature, to implement a sort of "NAN" function that
plays the role of the derivative of any non differentiable function? In
this way, any function without derivative can be implemented, and
everything is fine until you do not try to derive it. On the other hand,
if you try to derive, you obtain meaningless result (NAN) (and maybe
some error is generated!).

> have functions such as
> - rounding/truncating
> - mod/fmod, remainder
> - or even conditional expressions like a?b:c

BTW these things would be very useful to me too!


Best,
        G.

-- 
Giulio Bottazzi                 PGP Key ID:BAB0A33F 

CAFiM  Center for the Analysis of Financial Markets
LEM          Laboratory of Economics and Management
Sant'Anna School for Advanced Studies, Pisa, Italy
Phone: (+39)-050-883365       Fax: (+39)-050-883344
email: address@hidden    www.sssup.it/~bottazzi/

pgpndt34Y4CQj.pgp
Description: PGP signature