fisher

From untb v1.7-2 by Robin K S Hankin

Various functionality to implement Fisher's logseries

Various functions connected to Fisher's logseries including creation of synthetic datasets and estimation of Fisher's alpha

Keywords: math

Usage

fishers.alpha(N, S, give=FALSE)
fisher.ecosystem(N, S, nmax, alpha=NULL, c=0)

Arguments

N: Size of the ecosystem. In the case of fisher.ecosystem(), the expected size of the ecosystem
S: Number of species in ecosystem
alpha: In function fisher.ecosystem(), Fisher's $alpha$. If not supplied, it will be calculated from N and S.
give: In function fishers.alpha(), Boolean variable with default FALSE meaning to return alpha, and TRUE meaning to return a list containing x and alpha.
nmax: In function fisher.ecosystem(), the maximum number of species abundance classes to consider
c: In function fisher.ecosystem(), the rare species advantage term

Details

Function fishers.alpha() solves for $alpha$ given $N$ and $S$, as per Fisher's table 9, p55.

Given $N$ and $S$ (or $alpha$), function fisher.ecosystem() generates a Fisherian ecosystem with expected size $N$ and expected species count $S$.

References

R. A. Fisher and A. S. Corbet and C. B. Williams 1943. “The relation between the number of species and the number of individuals in a random sample of an animal population”, Journal of Animal Ecology, volume 12, pp 42--58

Examples

 fishers.alpha(N=100000,S=100)
#compare the Table value:
  100000/10^3.95991

Documentation reproduced from package untb, version 1.7-2, License: GPL

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