− | '''层次凝聚聚类 Hierarchical agglomerative clustering(HAC)'''标准算法的[[时间复杂度]]为<math>\mathcal{O}(n^3)</math> ,并且需要 <math>\mathcal{O}(n^2)</math> 占用内存,这使得它对于中等数据集来说效率太低了。然而,对于某些特殊情况,已知的最有效凝聚方法(复杂度 <math>\mathcal{O}(n^2)</math>)是: SLINK 用于[[单连接聚类 Single-linkage clustering]]<ref name="SLINK">{{cite journal | author=R. Sibson | title=SLINK: an optimally efficient algorithm for the single-link cluster method | journal=The Computer Journal | volume=16 | issue=1 | pages=30–34 | year=1973 | publisher=British Computer Society | url=http://www.cs.gsu.edu/~wkim/index_files/papers/sibson.pdf | doi=10.1093/comjnl/16.1.30}}</ref>, CLINK用于[[完全连接 complete-linkage clustering]]<ref name="CLINK">{{cite journal | author=D. Defays | title=An efficient algorithm for a complete-link method | journal=The Computer Journal | volume=20 | issue=4 | pages=364–366 | year=1977 | publisher=British Computer Society | url=http://comjnl.oxfordjournals.org/content/20/4/364.abstract | doi=10.1093/comjnl/20.4.364| doi-access=free }}</ref>。一般情况下的运行时可以缩减为<math>\mathcal{O}(n^2 \log n)</math> ,代价是进一步增加内存需求。在多数情况下,这种方法的内存消耗太大,并不实用。 | + | '''层次凝聚聚类 Hierarchical agglomerative clustering(HAC)'''标准算法的[[时间复杂度]]为<math>\mathcal{O}(n^3)</math> ,并且需要 <math>\mathcal{O}(n^2)</math> 占用内存,这使得它对于中等数据集来说效率太低了。然而,对于某些特殊情况,已知的最有效凝聚方法(复杂度 <math>\mathcal{O}(n^2)</math>)是: SLINK 用于[[单连接聚类 Single-linkage clustering]]<ref name="SLINK">{{cite journal | author=R. Sibson | title=SLINK: an optimally efficient algorithm for the single-link cluster method | journal=The Computer Journal | volume=16 | issue=1 | pages=30–34 | year=1973 | publisher=British Computer Society | url=http://www.cs.gsu.edu/~wkim/index_files/papers/sibson.pdf | doi=10.1093/comjnl/16.1.30}}</ref>, CLINK用于[[完全连接聚类 complete-linkage clustering]]<ref name="CLINK">{{cite journal | author=D. Defays | title=An efficient algorithm for a complete-link method | journal=The Computer Journal | volume=20 | issue=4 | pages=364–366 | year=1977 | publisher=British Computer Society | url=http://comjnl.oxfordjournals.org/content/20/4/364.abstract | doi=10.1093/comjnl/20.4.364| doi-access=free }}</ref>。一般情况下的运行时可以缩减为<math>\mathcal{O}(n^2 \log n)</math> ,代价是进一步增加内存需求。在多数情况下,这种方法的内存消耗太大,并不实用。 |