Comparison of External Indices.

D indicates the dataset containing N data objects, and its a priori partition with l categories is . The result obtained from clustering is , where k is the number of clusters. SS indicates that both objects belong to the same cluster of C and to the same group of partitions P; SD indicates points that belong to the same cluster of C and to different groups of P; DS indicates points that belong to different clusters of C and to the same group of P; and DD indicates points that belong to different clusters of C and to different groups of P.设数据集D包含N个数据对象，其基于l个类别的先验划分结果为[原文此处存在内容缺失]。聚类所得结果为，其中k为簇的数量。SS表示一对数据对象同时属于聚类结果C中的同一个簇，且同属于先验划分P的同一分组；SD表示同属于聚类结果C的同一个簇，但分属于先验划分P的不同分组的数据对象对；DS表示分属于聚类结果C的不同簇，但同属于先验划分P的同一分组的数据对象对；DD表示既分属于聚类结果C的不同簇，又分属于先验划分P的不同分组的数据对象对。