logkda {untb} | R Documentation |
Calculates Etienne's K(D,A)
logkda(a) logkda.a11(a)
a |
Count object |
Function logkda()
calculates K(D,A) using the method
appearing in Etienne (2005), supplementary online material. Function
logkda.a11
is a direct implementation of formula A11 in Etienne
(2005).
The formula is
ommitted...see PDF
where overline{s}(n_i,a_i) are Stirling numbers of
the first kind (see logS1
).
There are two functions here because logkda()
, although
faster, is based on a non-obvious method. Function logkda.a11()
is much slower (especially for large datasets) but the computational
method is a direct transcription of formula A11.
The two functions should produce numerically near-identical output.
Robin K. S. Hankin; logkda()
is an R transliteration of
pari/gp
code appearing in Etienne 2005 (supplementary online
material) due to Chave.
R. S. Etienne 2005. “A New Sampling Formula for Neutral
Biodiversity”. Ecology Letters, volume {8}, pp253–260.
doi: 10.111/j.1461-0248.2004.00717.x
a <- count(c(dogs=7,pigs=3,crabs=1,hogs=1,slugs=1)) logkda(a) logkda.a11(a)