allEdges {ggm}

All edges of a graph

Description

Finds the set of edges of a graph. That is the set of undirected edges if the graph is undirected and the set of arrows if the graph is directed.

Usage

allEdges(amat)

Arguments

amat

a square Boolean matrix, with dimnames, the adjacency matrix of a graph.

Value

a matrix with two columns. Each row of the matrix is a pair of indices indicating an edge of the graph. If the graph is undirected, then only one of the pairs (i,j), (j,i) is reported.

Author(s)

Giovanni M. Marchetti

See Also

cycleMatrix

Examples

## A UG graph
allEdges(UG(~ y*v*k +v*k*d+y*d))

## A DAG
allEdges(DAG(u~h+o+p, h~o, o~p))