Fig. 2

The clustering of the data. (a) is a histogram of the optimal $\tilde{h}$ values for the test data in 0.1 bins. (b) is a histogram of the ratio between the average intra-cluster and inter-cluster distances. Using the optimal τ for each cell, the average distance between responses to the same cell is calculated and divided by the average distance between responses to different cells. This ratio is less than one for all cells. It is plotted here in bins of width 0.05 showing that this ratio is near one for many cells; the average value is 0.87