R/betastatjac.R

In adiv: Analysis of Diversity

betastatjac <-
function(comm){ 
    comm <- ifelse(comm > 0, 1, 0) 
    N <- nrow(comm) 
    S <- ncol(comm[, colSums(comm)>0]) 
    sumNi <- sum(comm) 
    R <- rowSums(comm) 
    spmin <- apply(comm, 2, function(x) min((x * R)[x > 0])) 
    n0 <- spmin 
    for (i in 1:ncol(comm)) n0[i] <- sum(comm[, i] == 0 & R >= 
        spmin[i]) 
    NiT <- sum(n0) 
    betap <- (S*N-sumNi)/(S*(N-1)) 
    betam <- 1-betap 
    betaT <- NiT/(S*(N-1)) 
    betaN <- betap - betaT 
    res <- c(betap, betaT, betaN, betam) 
    names(res) <- c("beta", "betaT", "betaN", "sim") 
    return(res) 
 
}