R/as.bipartite.R

In SEELab/enaR: Tools for Ecological Network Analysis

#' Converts a network object (unipartite) to a two-mode (bipartite) network
#' representation.
#' 
#' Bipartite network approaches are often used for analyzing the
#' structure of interactions among species in communities.  Although
#' typically ecosystem networks are handled using a unipartite
#' representation, anlayzing them from a bipartite perspective may be
#' informative. This function provides an easy means for converting to
#' a bipartite representation as long as there is a natural division
#' to categorize species into distinct modes.
#' 
#' @param x A network object.
#' @param y A vector of membership values.
#' @return Returns a matrix with the species of one mode arrayed in rows and
#' the other in columns.
#' @author Matthew K. Lau
#' @examples
#' 
#' data(oyster)
#' as.bipartite(oyster, gl(2, 3))
#' 
#' @export as.bipartite
as.bipartite <- function(x = 'network object',y = 'membership vector'){
    y <- factor(y)
    unpack(x)$F[y == levels(y)[1],y == levels(y)[2]]
}