Figure 1: Clustering results of the Wu-Huberman algorithm for the two-moon pattern with different pole point selections. (a) The distribution of the voltage values when 22nd and 86th points have been chosen as the poles. (b) The clustering results corresponding with (a). (c) The distribution of voltage values when the 45th and 86th points have been chosen as the poles under the same dataset, algorithm, and parameters with (a). (d) The clustering results corresponding to (c). (e) The graph of determining the pole points. The -axis is the data point number, and the -axis is the value of sparse rate .