On Sat, Aug 9, 2014 at 1:40 PM, Marc Glisse <marc.gli...@inria.fr> wrote: > __x = result_type(2.0) * __aurng() - 1.0;
You're right, we of course need the negatives as well. > Assuming the 2 coordinates are obtained through a rescaling x->2*x-1, if > __sq is not exactly 0, it must be between 2^-103 and 1 (for ieee > double), so I am not sure hypot gains that much (at least in my mind > hypot was mostly a gain close to 0 or infinity, but maybe it has more > advantages). It can only hurt speed though, so not a big issue. Depending on how similar in size the two values are, not using hypot() can drop quite a few bits. Especially with the scaling through division this error can be noticeable. Better be sure. Maybe at some point I have time to investigate the worst case scenario for the numbers in question but until this shows hypot isn't needed it's best to leave it in. I've committed the patch.