Hierarchical topological clustering and meaningful outliers
摘要
Topological methods have the potential of exploring the shape of datasets across different scales by analyzing topological features (connected components, holes) that persist at different spatial resolutions. Given a distance defined on a dataset, we propose a hierarchical topological clustering algorithm that creates clusters from the components of an associated one parameter family of simplicial complexes. Unlike DBSCAN, this strategy is suitable to understand multiclustering phenomena in hierarchical data and does not require blind parameter choices. Cluster configurations that persist for large parameter ranges are considered dominant. While popular methods like K-means or K-medoids fail to identify non convex clusters, the proposed algorithm creates clusters of any shape. Moreover, its stability under noise is quantifiable through distances defined on persistence diagrams, a property not enjoyed by standard hierarchical clustering. Unlike linkage strategies such as centroid or median, this algorithm can be implemented with any distance choice, not just Euclidean distances. The complexity of the algorithm is bounded from above by