Computes a smooth approximation to the Hausdorff distance between the vertices of a mapper. Implements the equation in Section 5 of the original Mapper paper. $$ d_h(X_i, X_j) = \max{( \frac{\sum_y \min_x(d(x, y)) }{n_j}, \frac{\sum_x \min_y(d(x, y)) }{n_i})} $$ where \(x, y\) are elements of the clusters \(C_i, C_j\) respectively, and \(X_i, X_j\) are the clusters corresponding vertices in the mapper. See the reference below for more details.

WARNING: This function may be very computationally expensive.

hausdorff_distance(m)

Arguments

m

A MapperRef object.

Value

A dist object with Size equal to the number of vertices.

Details

Currently, this requires the RANN to be installed, and only considers euclidean distance.

References

Singh, Gurjeet, Facundo Memoli, and Gunnar E. Carlsson. "Topological methods for the analysis of high dimensional data sets and 3d object recognition." SPBG. 2007.