data.frame which contains the graph
description, must have two columns n1 and
n2 filled with node IDs, each row denoting there
is an edge from n1 to n2.
file
file where the graph description is written
keepOnlyReciprocal
if TRUE dataGraph is
restricted to reciprocal edges, else all edges are kept
(default).
Value
This function returns the argument 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.