[PATCH] Add sinh(tanh(x)) and cosh(tanh(x)) rules

[Wilco Dijkstra]

Hi,

>> Maybe I am crazy, or the labels here are wrong, but that looks like the
>> error is three times as *big* after the patch.  I.e. it worsened instead
>> of improving.

This error is actually 1ULP, so just a rounding error. Can't expect any better than that!

> with input  :  = 9.99999880790710449218750000000000000000000000000000e-01
> cosh: before:  = 2.04800000000000000000000000000000000000000000000000e+03
> cosh: after :  = 2.04800024414062500000000000000000000000000000000000e+03
> cosh: mpfr  :  = 2.04800006103515897848424084406334262726138617589463e+03
> error before:  = 6.10351589784842408440633426272613861758946325324235e-05
> error after :  = 1.83105466021515759155936657372738613824105367467577e-04

It may be less confusing to print relative error or ULP error...

Wilco