docs: public Clustering<Model> run(Relation<V> relation) {
      final DBIDs ids = relation.getDBIDs();
  
      // Degenerate result:
      if(ids.size() < minpts) {
        Clustering<Model> result = new Clustering<>("DBSCAN Clustering", "dbscan-clustering");
        result.addToplevelCluster(new Cluster<Model>(ids, true, ClusterModel.CLUSTER));
        return result;
      }
  
      double gridwidth = this.gridwidth; // local copy.
      if(gridwidth < 2. * epsilon) {
        LOG.warning("Invalid grid width (less than 2*epsilon, recommended 10*epsilon). Increasing grid width automatically.");
        gridwidth = 2. * epsilon;
      }
      return new Instance<V>(getDistanceFunction(), epsilon, minpts, gridwidth).run(relation);
    }