Description of check_matrix

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check_matrix

PURPOSE

check_matrix(A) --- check if A is a valid adjacency matrix for a graph

SYNOPSIS

function ok = check_matrix(A)

DESCRIPTION

 check_matrix(A) --- check if A is a valid adjacency matrix for a graph

CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

SOURCE CODE

0001 function ok = check_matrix(A)
0002 % check_matrix(A) --- check if A is a valid adjacency matrix for a graph
0003 
0004 ok = 0;
0005 
0006 % make sure matrix is equare
0007 [nr,nc] = size(A);
0008 if (nr ~= nc) 
0009     return
0010 end
0011 
0012 % see if the matrix is zero-one
0013 B = (A>0); % convert to logical (so 0,1).
0014 if (nnz(A-B)>0)
0015     return
0016 end
0017 
0018 % check if symmetric
0019 if (nnz(A-A')>0)
0020     return
0021 end
0022 
0023 % check the diagonal
0024 if (any(diag(A)>0)) 
0025     return
0026 end
0027 
0028 % all tests passed
0029 ok = 1;

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