Re: [boost] Re: [Ann] Proposed Math library additions (complexnumberinverse trig functions).

From: John Maddock (john_at_[hidden])
Date: 2005-04-08 05:21:03

>         Arrgh! I only coded the complex versions of sinc and sinhc!

:-)  It happens.

>         I will look at your implementation tomorrow, but I feel it
> would perhaps be simpler to replace my files with yours or merge the
> implementations (specialization for scalars and specialization for
> complexes), and update the library documentation. I'd also like to add
> valarray support, at least for the scalars (pending the language
> decisions concerning layout guaranties), at some point, though rereading
> the discussion of two years ago this may prove contentious.

>         At any rate, I believe this is an enrichment of an existing,
> accepted, library, and as such does not warrant a separate review.
> Adding valarray support might warrant one, though, since there has been
> controversy (and thus the opportunity for improvement thru review).

OK, since my implementations are strictly complex number only, yours would 
still be needed for reals.

BTW, I haven't implemented asinh/acosh as such: these are trivial variations 
of asin/acos (which are implemented).  Just to be different, atan is a 
trivial variation of atanh: C99 expressed the relationship this way around, 
so I just followed.

>      I do not have institutional free access from my "beloved
>workplace" (grumble...).

No nor do I, but I've used this authors work before, and the current 
exchange rate makes ACM access not too painful...

>> Any others? You've got my curiosity roused...
>
>      In the stopgap series of implementations that my "special
>functions library" is, I would have simply used a succession of
>truncated series expansion, at least near zero (like I did for the
>various other functions), and then rely on whatever exponential function
>was coded in the user's platform's standard library.

Yep, that's easy enough: take a look at my log1p: the series evaluation is 
all boilerplate, so doing the same for expm1 is just a case of writing a 
short function object that calculates successive terms each time it's 
called.

John.