matthiasm@8: function [edge_id, nedges] = assignEdgeNums(adj_mat)
matthiasm@8: % give each edge a unique number
matthiasm@8: % we number (i,j) for j>i first, in row, column order.
matthiasm@8: % Then we number the reverse links
matthiasm@8: 
matthiasm@8: nnodes = length(adj_mat);
matthiasm@8: edge_id = zeros(nnodes);
matthiasm@8: e = 1;
matthiasm@8: for i=1:nnodes
matthiasm@8:   for j=i+1:nnodes
matthiasm@8:     if adj_mat(i,j)
matthiasm@8:       edge_id(i,j) = e;
matthiasm@8:       e = e+1;
matthiasm@8:     end
matthiasm@8:   end
matthiasm@8: end
matthiasm@8: 
matthiasm@8: nedges = e-1;
matthiasm@8: tmp = edge_id;
matthiasm@8: ndx = find(tmp);
matthiasm@8: tmp(ndx) = tmp(ndx)+nedges;
matthiasm@8: edge_id = edge_id + triu(tmp)';
matthiasm@8: 
matthiasm@8: 
matthiasm@8: if 0
matthiasm@8: ndx = find(adj_mat);
matthiasm@8: nedges = length(ndx);
matthiasm@8: nnodes = length(adj_mat);
matthiasm@8: edge_id = zeros(1, nnodes*nnodes);
matthiasm@8: edge_id(ndx) = 1:nedges; 
matthiasm@8: edge_id = reshape(edge_id, nnodes, nnodes);
matthiasm@8: end