\name{annotReciprocal}
 \alias{annotReciprocal}
 \title{annotReciprocal}
 \usage{
   annotReciprocal(dataGraph, file,
     keepOnlyReciprocal = FALSE)
 }
 \arguments{
   \item{dataGraph}{data.frame which contains the graph
   description, must have two columns \code{n1} and
   \code{n2} filled with node IDs, each row denoting there
   is an edge from \code{n1} to \code{n2}.}
 
   \item{file}{file where the graph description is written}
 
   \item{keepOnlyReciprocal}{if TRUE \code{dataGraph} is
   restricted to reciprocal edges, else all edges are kept
   (default).}
 }
 \value{
   This function returns the argument \code{dataGraph} with
   an additional column named 'reciprocal' which contains
   TRUE if the edge described by the row is reciprocal, and
   FALSE if it is not reciprocal.
 }
 \description{
   This function notes edges of a graph as reciprocal or
   not.
 }
 \examples{
 dg <- data.frame(n1=c("A","B","B","C","C","D","E","F"),n2=c("B","G","A","B","D","C","F","E"))
 annotReciprocal(dataGraph=dg)
 }
 \author{
   Anne Biton
 }