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