Hi Aaron your guess is correct, my code tis rying to add int values to the graph. is it a bad idea to use typedef std::pair <int, int> TEdge; for add_edge(...) to a graph, below is my relevant source code snippet. Best Bernhard -------------------------------------------------------------------------- iter = this->Elements.begin(); while(iter != this->Elements.end()) { aAtomicElement = (*iter).second; for (str_iter=aAtomicElement.AE_PinList.begin(); str_iter!= aAtomicElement.AE_PinList.end(); ++str_iter) for (str_iter2=str_iter+1; str_iter2!= aAtomicElement.AE_PinList.end(); ++str_iter2) { cout << "\n Params before call Add_edge(...) function \n "; cout << "edge as [<std::string>]: "<< *str_iter << " ::" << *str_iter2 << " \n "; cout << "edge as [<int> <int>] : "<< index_of_element( this->VertexNamesList, *str_iter) << " :: " << index_of_element( this->VertexNamesList, *str_iter2) << " \n "; OneEdge.first = index_of_element( this->VertexNamesList, *str_iter); OneEdge.second = index_of_element( this->VertexNamesList, *str_iter2); tie(e, inserted) = add_edge(OneEdge.first, OneEdge.second, g); if (inserted) { v = source(e, g); VertexNamesMap[v] = *str_iter; v = target(e, g); VertexNamesMap[v] = *str_iter2; EdgeNamesMap[e] = aAtomicElement.AE_Name; // EdgeIndexMap[e] = StrToInt(aAtomicElement.AE_ID); cout << " using Edge -->" << EdgeNamesMap[e] ; WeightMap[e] = 1 ; } } iter ++; } // while ... break; -- Psst! Geheimtipp: Online Games kostenlos spielen bei den GMX Free Games! http://games.entertainment.gmx.net/de/entertainment/games/free