Daniel@0: function U = mk_undirected(G)
Daniel@0: 
Daniel@0: [nr nc] = size(G);
Daniel@0: U = G;
Daniel@0: for i=1:nr
Daniel@0:   for j=1:nc
Daniel@0:     if U(i,j)==1
Daniel@0:       U(j,i) = 1;
Daniel@0:     end
Daniel@0:   end
Daniel@0: end