wolffd@0: function [T, pre, post, cycle] = mk_rooted_tree(G, root)
wolffd@0: % MK_ROOTED_TREE Make a directed tree pointing away from root
wolffd@0: % [T, pre, post, cycle] = mk_rooted_tree(G, root)
wolffd@0: 
wolffd@0: n = length(G);
wolffd@0: T = sparse(n,n); % not the same as T = sparse(n) !
wolffd@0: directed = 0;
wolffd@0: [d, pre, post, cycle, f, pred] = dfs(G, root, directed);
wolffd@0: [junk, pre2] = sort(d);
wolffd@0: assert(isequal(pre, pre2))
wolffd@0: [junk, post2] = sort(f);
wolffd@0: assert(isequal(post, post2));
wolffd@0: %[d, pre, post, cycle, f, pred] = dfs(G, [], directed);
wolffd@0: for i=1:length(pred)
wolffd@0:   if pred(i)>0
wolffd@0:     T(pred(i),i)=1;
wolffd@0:   end
wolffd@0: end
wolffd@0: