docs: protected boolean dimensionIsRelevant(int dimension, Relation<V> relation, DBIDs points) {
      double min = Double.POSITIVE_INFINITY, max = Double.NEGATIVE_INFINITY;
      for(DBIDIter iter = points.iter(); iter.valid(); iter.advance()) {
        double xV = relation.get(iter).doubleValue(dimension);
        min = (xV < min) ? xV : min;
        max = (xV > max) ? xV : max;
        if(max - min > w) {
          return false;
        }
      }
      return true;
    }