1 Introduction
Clustering, an essential data analysis tool in pattern analysis and machine learning, is a data-driven task that attempts to explore knowledge from unlabeled data purely. In a multitude of science and engineering fields where the label information is unobservable or costly to obtain, many applications can be considered as typical instances of clustering, such as the astronomical data analysis [1], the medical analysis [2], the gene sequencing [3], and the information retrieval [4], [5], [6], [7].