bfsearch function

Breadth first search

Breadth-first search of a connected undirected graph.

bfsearch(amat, v = 1)

Arguments

• amat: a symmetric matrix with dimnames specifying the adjacency matrix of the undirected graph
• v: an integer, indicating the starting node of the search. Defaults to the first node.

Details

Breadth-first search is a systematic method for exploring a graph. The algorithm is taken from Aho, Hopcroft & Ullman (1983).

Returns

• tree: the edge matrix of the resulting spanning tree

• branches: a matrix with two columns, giving the indices of the branches of the spanning tree

• chords: a matrix with two columns, giving the indices of the chords of the spanning tree

References

Aho, A.V., Hopcrtoft, J.E. & Ullman, J.D. (1983). Data structures and algorithms. Reading: Addison-Wesley.

Thulasiraman, K. & Swamy, M.N.S. (1992). Graphs: theory and algorithms. New York: Wiley.

Author(s)

Giovanni M. Marchetti

See Also

UG, findPath, cycleMatrix

Examples

## Finding a spanning tree of the butterfly graph
bfsearch(UG(~ a*b*o + o*u*j))
## Starting from another node
bfsearch(UG(~ a*b*o + o*u*j), v=3)