Use sincos optimization in merc_e_forward. Revised timing data...

Times per call in ns = nanoseconds.

                Fedora 31    Ubuntu 18
                g++-9.3.1    g++-7.5.0
                fwd   inv    fwd   inv
    old merc    207   461    217   522
    new merc    159   457    137   410
      etmerc    212   196    174   147

The new forward method is now 25% faster (resp 35% faster) on Fedora
31 (resp Ubuntu 18).  The new inverse method is the same speed (resp 20%
faster) on Fedora 31 (resp Ubuntu 18).

The accuracy is hardly affected: rms error increases from 0.30 nm to
0.33 nm, max error increases from 1.83 nm to 1.84 nm (a barely
noticeable degradation).

0 files changed, 0 insertions, 0 deletions