ldexp and frexp benchmark between Mir, C and Phobos

[Guillaume Piolat]

On Monday, 31 December 2018 at 13:24:29 UTC, kinke wrote:
> On Sunday, 30 December 2018 at 13:39:44 UTC, Guillaume Piolat 
> wrote:
>> Been waiting for an exp() rewrite. And Boost-licensed! I'm 
>> using expf() from whatever libc is shipped and the variability 
>> of results and lack of control is annoying.
>
> exp != {ld,fr}exp. Phobos includes a proper single/double 
> precision exp implementation since v2.082 and is Boost 
> licensed...

llvm_exp (defers to C runtime) gives considerable speed 
improvement over `std.math.exp`.

I've tested `expf` form the VS runtime exhaustively for 32-bit 
`float` and it showed the relative accuracy was within < 0.0002% 
of std.math.exp,

It's not concerning at all, what is more is the variability of C 
runtime though vs a D function. Looking for speed AND control :)