Convert between directed and undirected graphs

Description

as.directed converts an undirected graph to directed, as.undirected is the opposite, it converts a directed graph to undirected.

Usage

as.directed(graph, mode = c("mutual", "arbitrary")) 
as.undirected(graph, mode = c("collapse", "each")) 

Arguments

Details

Conversion algorithms for as.directed:

arbitrary
The number of edges in the graph stays the same, an arbitrarily directed edge is created for each undirected edge.
mutual
Two directed edges are created for each undirected edge, one in each direction.

Conversion algorithms for as.undirected:

each
The number of edges remains constant, an undirected edge is created for each directed one, this version might create graphs with multiple edges.
collapse
One undirected edge will be created for each pair of vertices which are connected with at least one directed edge, no multiple edges will be created.

Value

A new graph object.

Author(s)

Gabor Csardi csardi@rmki.kfki.hu

See Also

simplify for removing multiple and/or loop edges from a graph.

Examples

g <- graph.ring(10)
as.directed(g, "mutual")
g2 <- graph.star(10)
as.undirected(g)