Use of C99 extra long double math functions after r236148

Peter Jeremy peter at rulingia.com
Sun Jul 29 22:27:31 UTC 2012


[For anyone not previously in on this discussion, this is part of an
ongoing discussion that has been occurring off-list in the absence of
a suitable list.  It is planned to archive that discussion here,
subject to all the participants agreeing].

On 2012-Jul-28 20:16:50 -0500, Stephen Montgomery-Smith <stephen at missouri.edu> wrote:
>One thing your program doesn't check are things like:
>
>real part of casinh(-0+I*x) is -0
>imaginary part of casinh(x-I*0) is -0
>
>etc, where x is finite, non-zero.  (This follows from casinh being odd 
>and conjugate invariant.)

As it currently exists, my program solely implements the checks in
WG14/N1256 G.6.  I hadn't considered extending that to verifying that
purely real or imaginary inputs give purely real or imaginary outputs,
with the appropriately signed zero.  This might be reasonable but it's
not completely trivial to implement in general since the domains of
the real part can be different.  I'm less sure of the next logical
step, which is to check things like
  casinh(x + I*0) = asinh(x) + I*0

-- 
Peter Jeremy
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