Renkonen similarity index

The Renkonen similarity index (P), is a measure of dissimilarity between two communities (sites), based on relative (proportional) abundances formula_1 of individuals of composite species. It was developed by the botanist Olavi Renkonen and published in 1938.
formula_2,
formula_3 - percentage struture of one set,
formula_3 - percentage struture of second set.
The codomain of this distance function ranges from 1 (identical proportional abundances) to 0 (no taxa shared).