R/mete2con.R

In mlammens/meteR: Fits and plots macroecological patterns predicted by the Maximum Entropy Theory of Ecology (METE)

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#'
#' @description
#' \code{function.name} what it does
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#' @param arg description of arg
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#' @author Andy Rominger <ajrominger@@gmail.com>
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###########  functions for calculating METE SAD under 2nd resource constraint  ###########

mete2con.lik <- function(zeta,data) {
	this.fun <- Vectorize(function(x) -sum(log(mete.phi2con(data,sum(data),x))))
	
	out <- this.fun(zeta)
	out[!is.finite(out)] <- NA
	
	return(out)
}

mete2con.mle <- function(data) {
	nlm(mete2con.lik,p=1,data=data)
}

##	normalized SAD
mete.phi2con <- function(n,N0,zeta) {
	kern <- function(x) exp(-zeta*x)/(x^2)
	Z <- sum(kern(1:N0))
	
	return(kern(n)/Z)
}

##	normalized CDF
mete.phi2con.cdf <- function(N0,zeta) {
	return(list(x = 1:N0, y = cumsum(mete.phi2con(1:N0,N0,zeta))))
}