Run this code tree<-graph_from_literal(1-+2:3,3-+5,1-+4); graph.bfs(tree,root=1, neimode="out",father=TRUE,order=TRUE,unreachable FALSE) I do not understand why the father values will give NA 1 1 3 1 rather than NA 1 1 1 3 The reason I am doing this is to obtain the values(by vertex names) or some index of each individual branch in tree. Does anyone have any ideas on how to do this? Yours sincerely, Justin *I check my email at 9AM and 4PM everyday* *If you have an EMERGENCY, contact me at +447938674419 <07938%20674419>(UK) or +60125056192 <+60%2012-505%206192>(Malaysia)* [[alternative HTML version deleted]]