R/RV.R

In guiblanchet/countComm: Counting procedure to be more cost effective when sampling ecological communities

RV <-
function(X, Y) {
### F. Guillaume Blanchet - Décembre 2013
#########################################
	#CC# General checks
	if (nrow(X) != nrow(Y)) {
		stop("'X' needs to have the same number of rows as 'Y'")
	}
	if (nrow(X) == 1){
		stop("Impossible to calculate RV using 1 object")
	}
	
	Y <- scale(Y, scale = FALSE)
	X <- scale(X, scale = FALSE)
	
	XXt <- tcrossprod(X)
	YYt <- tcrossprod(Y)
	
	rv <- sum(diag(XXt %*% YYt))/(sum(diag(XXt %*% XXt)) * sum(diag(YYt %*% YYt)))^0.5
	
	return(rv)
}