proof of CORE-MATH sinh

[Paul Zimmermann]

Dear FPbench community,

a proof of correctness of the CORE-MATH sinh routine is now available
from the web page:

https://core-math.gitlabpages.inria.fr/sinh.pdf

Your feedback is welcome, for example:

* find issues in the proofs of Theorems 1 and 2

* improve the value of \epsilon = 33 \cdot 2^-57 in Algorithm 1

Our aim is to publish proofs of most CORE-MATH binary64 functions.

This will require some exhaustive tests in some regions where a paper
proof is too difficult. If you have access to large clusters, your help
is most welcome.

To get an idea, checking a full binade of a function takes of the order
of 6000 hours (real time) on a Intel Xeon Gold 6130 with 64 cores.

This is quite expensive, but will benefit the whole scientific community,
since CORE-MATH binary64 functions are being integrated into GNU libc,
and might be integrated into other libraries.

Paul Zimmermann