[CLN-list] Types in cl_R
Richard B. Kreckel
kreckel at thep.physik.uni-mainz.de
Wed Nov 17 22:32:03 CET 2004
On Tue, 16 Nov 2004, Isidro [iso-8859-15] Cachadiña Gutiérrez wrote:
> I am using cln with real numbers. I have a problem in the expt function...
[...]
> I also can define this function as:
>
> cln::cl_R expt(cln::cl_R x, cln::cl_R y)
> {
> return exp(x*ln(y));
> }
>
> And It works fine, but I think that It have to be defined somewhere in the
> library.
Well, only if `x' is positive, right? Or if `y' is integer. But that
signature is there, as you've already seen. Otherwise, the range of the
exponentiation function isn't R anyway, so you could equally well use
expt(cl_N,cl_N), returning an cl_N object.
Maybe it would be worthwhile though, considering the fact that we also
have sqrt(cl_R) defined only for arguments >= 0 without type checks for
that. But given the other signatures, I see only very limited use.
Saludos
-richy.
--
Richard B. Kreckel
<http://www.ginac.de/~kreckel/>
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