Function to conveniently add an arc to an existing DAG.
Usage
add.arc(dag, arc, type = 0)
Arguments
dag
The DAG to which an arc should be added.
arc
A vector of length 2, indicating from which node (first element) to
which node (second element) the arc is to go.
Note: the node numbering follows the numbering of the existing
DAG (as shown in dag.draw with option numbering=T
type
0 (=default) for a directed arc, 1 for an undirected association.
Value
A DAG with the arc (and corresponding arc.type) added, and with the
path-related variables (paths, pathsN, path.status, searchType, searchRes) removed.