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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


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