distances

This module provides functions to compute distances between orders.

distance_matrix(instance, distance_function)

Returns a matrix of the pairwise distance between all orders of the instance.

Parameters:

• instance (OrdinalInstance) – The instance to take the orders from.

• distance_function (function) – The distance function to use. It should take two orders as input.

Returns:

A Numpy array of the pairwise distances, coordinates being the index of the orders in the order list of the instance.

Return type:

numpy array

kendall_tau_distance(order1, order2, normalise=False)

Returns the Kendall’s tau distance between two orders.

Parameters:

• order1 (tuple) – The first order.

• order2 (tuple) – The second order.

• normalise (bool) – if True the result is normalised by the number of comparison done

Returns:

The Kendall’s tau distance between the two orders.

Return type:

int

sertel_distance(order1, order2)

Returns the Sertel’s distance between two orders.

Parameters:

• order1 (tuple) – The first order.

• order2 (tuple) – The second order.

Returns:

The Sertel’s distance between the two orders.

Return type:

float

spearman_footrule_distance(order1, order2)

Returns the Spearman’s footrule distance between two orders.

Parameters:

• order1 (tuple) – The first order.

• order2 (tuple) – The second order.

Returns:

The Spearman’s footrule distance between the two orders.

Return type:

float