Ruzicka or weighted Jaccard distance
ruzicka(x, y)Numeric vectors.
The Ruzicka distance between x and y. The distance is
not defined if all elements in x and y are zero, and we
return NaN in this case.
For vectors x and y, the Ruzicka distance is defined as
$$d(x, y) = 1 - \frac{\sum_i \min(x, y)}{\sum_i \max(x, y)}.$$ Relation
to other definitions:
Equivalent to vegdist() with method = "jaccard".
Related to the Bray-Curtis distance, \(d_r = 2 d_{bc} / (1 + d_{bc})\).