graphisspantree - Determine if tree is spanning tree

Syntax

Arguments

G	N-by-N sparse matrix whose lower triangle represents an undirected graph. Nonzero entries in matrix G indicate the presence of an edge.

Description

Tip   For introductory information on graph theory functions, see Graph Theory Functions in the Bioinformatics Toolbox User's Guide.

TF = graphisspantree(G) returns logical 1 (true) if G is a spanning tree, and logical 0 (false) otherwise. A spanning tree must touch all the nodes and must be acyclic. G is an N-by-N sparse matrix whose lower triangle represents an undirected graph. Nonzero entries in matrix G indicate the presence of an edge.

Examples

1. Create a phytree object from a phylogenetic tree file.

   tr = phytreeread('pf00002.tree')
   
   Phylogenetic tree object with 33 leaves (32 branches)

2. Create a connection matrix from the phytree object.

   [CM,labels,dist] = getmatrix(tr);

3. Determine if the connection matrix is a spanning tree.

   graphisspantree(CM)
   
   ans =
   
        1

4. Add an edge between the root and the first leaf in the connection matrix.

   CM(end,1) = 1;

5. Determine if the modified connection matrix is a spanning tree.

   graphisspantree(CM)
   
   ans =
   
        0

References

[1] Siek, J.G., Lee, L-Q, and Lumsdaine, A. (2002). The Boost Graph Library User Guide and Reference Manual, (Upper Saddle River, NJ:Pearson Education).

See Also

graphallshortestpaths | graphconncomp | graphisdag | graphisomorphism | graphmaxflow | graphminspantree | graphpred2path | graphshortestpath | graphtopoorder | graphtraverse | isspantree

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