code: func (sorter sorter) Less(i, j int) bool {
  	return sorter.vertices[i].less(sorter.config, sorter.vertices[j])
  }
docs: // the following methods are required for sort.Interface.  We
  // use the standard libraries sort here as it uses an adaptive
  // sort and we really don't expect there to be a ton of dimensions
  // here so mulithreaded sort in this repo really isn't
  // necessary.