Description of nsptrees

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nsptrees

PURPOSE

nsptrees(g) --- number of spanning trees of g.

SYNOPSIS

function nt = nsptrees(g)

DESCRIPTION

 nsptrees(g) --- number of spanning trees of g.
 This computes the number of spanning trees of g using the matrix-tree
 theorem.

CROSS-REFERENCE INFORMATION

This function calls:

• deg deg: degree of a vertex or degree sequence
• matrix matrix(g) --- return (a copy of) the adjacency matrix of g
• nv nv(g) --- number of vertices in g

This function is called by:

SOURCE CODE

0001 function nt = nsptrees(g)
0002 % nsptrees(g) --- number of spanning trees of g.
0003 % This computes the number of spanning trees of g using the matrix-tree
0004 % theorem.
0005 
0006 A = diag(deg(g)) - matrix(g);
0007 n = nv(g)-1;
0008 nt = det(A(1:n,1:n));

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