Mail Archives: djgpp/1998/05/13/04:51:16
On Tue, 12 May 1998, Kbwms wrote:
> Clearly, one of the problems is that no one pays any attention to
> what ELEFUNT produces.
It is more probable that the problem was noted but never got to the
top of somebody's todo list.
> I intend to run the stuff through my version of ELEFUNT because it
> is much more comprehensive. Of course, I'll report the results from
> ELEFUNT, too.
It might be a better idea to change the version of ELEFUNT in djtst201
as well. It is only for DJGPP's needs, so there's no problem to make
any changes there we see fit, if they will make the testing more
exhaustive.
> The scandalous behavior reported above for the identity
> sinh(x) = -sinh(-x) is shown again:
>
> sinh(x) vs. sinh(-x) for random values
> x = 1.7313932765, sinh(x) + sinh(-x) = 5.247538515E-17
> x = 2.5142214602, sinh(x) + sinh(-x) = -5.074066167E-17
> x = 1.8964167239, sinh(x) + sinh(-x) = 7.090682208E-17
> x = 2.5792200716, sinh(x) + sinh(-x) = 3.955169525E-16
> x = 2.1011919701, sinh(x) + sinh(-x) = 3.851086117E-16
Why is this scandalous? The relative error here is less than the
double-precision machine epsilon, so where's the scandal? (Of course,
if the accuracy can be improved even more, I'm for it.)
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