mcintosh_d {abdiv} | R Documentation |
McIntosh dominance index D
mcintosh_d(x)
x |
A numeric vector of species counts. |
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
.
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
.
McIntosh RP. An index of diversity and the relation of certain concepts to diversity. Ecology. 1967;48:1115-1126.
x <- c(15, 6, 4, 0, 3, 0)
mcintosh_d(x)