tuckey_ninther.h

// Use Tuckey's ninther technique or median of 3 for pivot selection.
// Get the median out of 3 medians of 9 elements
// (first, first + half, last - 1)
// (first + 1, first + half - 1, last - 2)
// (first + 2, first + half + 1, last - 3)
_VSTD::__sort3<_Compare>(__first,
                         __first + __half_len,
                         __last - difference_type(1),
                         __comp);
_VSTD::__sort3<_Compare>(__first + difference_type(1),
                         __first + (__half_len - 1),
                         __last - difference_type(2),
                         __comp);
_VSTD::__sort3<_Compare>(__first + difference_type(2),
                         __first + (__half_len + 1),
                         __last - difference_type(3),
                         __comp);
_VSTD::__sort3<_Compare>(__first + (__half_len - 1),
                         __first + __half_len,
                         __first + (__half_len + 1),
                         __comp);
_VSTD::iter_swap(__first, __first + __half_len);

Mispelling: It is "Tukey's" ninther not "Tuckey's"