code: void clear() {
  		count = 0;
  		m0 = 0.0;
  		clusters.space.setToOrigin(m1);
  		clusters.space.setToOrigin(m2);
  		var = 0.0;
  		key = null;
  	}
docs: Completely clears this cluster. All points and their associated mass is
  removed along with any key that was assigned to the cluster,