mcintosh_d {abdiv}

McIntosh dominance index D

Description

McIntosh dominance index D

Usage

mcintosh_d(x)

Arguments

x

A numeric vector of species counts.

Details

For a vector x of raw species counts, the McIntosh dominance index is defined as

D = \frac{N - U}{N - \sqrt{N}},

where N is the total number of counts and U = \sqrt{\sum_i x_i^2}.

This index is appropriate only for raw counts, not transformed counts or proportions.

Equivalent to mcintosh_d() in skbio.diversity.alpha.

Value

The McIntosh dominance index, 0 \leq D < 1. The index is undefined when the total number of counts is 1 or 0, in which case we return NaN.

References

McIntosh RP. An index of diversity and the relation of certain concepts to diversity. Ecology. 1967;48:1115-1126.

Examples

x <- c(15, 6, 4, 0, 3, 0)
mcintosh_d(x)