label_parallel_edges

graph_tool.generation.label_parallel_edges(g, mark_only=False, eprop=None)

Label edges which are parallel, i.e, have the same source and target vertices. For each parallel edge set \(PE\), the labelling starts from 0 to \(|PE|-1\). If mark_only==True, all parallel edges are simply marked with the value 1. If the eprop parameter is given (a EdgePropertyMap), the labelling is stored there.