protected static void cross(_Cartesian t, ref _Cartesian u, ref _Cartesian v){ t.xs = u.ys * v.zs - u.zs * v.ys; t.ys = u.zs * v.xs - u.xs * v.zs; t.zs = u.xs * v.ys - u.ys * v.xs; }
static protected void set(_Cartesian v, double x, double y, double z) { v.xs = x; v.ys = y; v.zs = z; }