message: Simplify strange iterator use
  the syntax with [] is already used a few lines above
diff: @@ -100,7 +100,7 @@ void choose_n_farthest_points(Kernel const &k,
  *dist_it++ = dist_to_L[curr_max_w];
  std::size_t i = 0;
  for (auto&& p : input_pts) {
  - double curr_dist = sqdist(p, *(std::begin(input_pts) + curr_max_w));
  + double curr_dist = sqdist(p, input_pts[curr_max_w]);
  if (curr_dist < dist_to_L[i])
  dist_to_L[i] = curr_dist;
  ++i;
  