Hi, I have two problems class Weights: ... g = Graph(directed=True) weights = g.new_edge_property('object') vertex_one = g.add_vertex() vertex_two = g.add_vertex() edge = g.add_edge(vertex_one, vertex_two) weights[edge] = Weights(1) g.shortest_path(vertex_one, vertex_two, weights) This raises ValueError: property map 'dist_map' is not of scalar type. Is there a function I can implement in Weights for it to return a scalar value to be used during calculation of shortest path. Secondly, consider a directed graph where the edge weight is a function of cost at edge's origin vertex, i.e. the weight class is defined as: class Weights: .... def get_weight(current_cost): return self.cost * current_cost Hence during calculation of shortest_path/distance, is it possible to pass the weight at the traversed/visited edge to get the cost of the edge. -- View this message in context: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/... Sent from the Main discussion list for the graph-tool project mailing list archive at Nabble.com.