private ClusterList beginBottomUp() {
		Cluster newCluster;
		ClusterList firstClusterList = new ClusterList();
		for (int i = 0; i < this.instances.numInstances(); i++) {
			newCluster = new Cluster(this.instances.instance(i));
			firstClusterList.add(newCluster);
		}
		return firstClusterList;
	}