mcintosh_e {abdiv}

McIntosh's evenness measure E

Description

McIntosh's evenness measure E

Usage

mcintosh_e(x)

Arguments

x

A numeric vector of species counts.

Details

For a vector x of raw species counts, the McIntosh evenness measure is

E = \frac{\sqrt{\sum_i x_i^2}}{\sqrt{(N - S + 1)^2 + S - 1},}

where N is the total number of counts and S is the total number of species observed.

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

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

Value

McIntosh's evenness measure, 0 < E \leq 1. The index is undefined when the total number of counts is 0, in which case we return NaN.

References

Heip C, Engels P. Comparing Species Diversity and Evenness Indices. J. Mar. Bioi. Ass. U.K. 1974;54:559-563.

Examples

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