创建没有图的边描述符

Question

在我的项目中，我使用一个文件来存储所有边；另一个存储边缘概率。我想将Boost 库用于图形，unordered_map 用于概率。我有以下代码。

typedef boost::adjacency_list <boost::vecS, boost::vecS, boost::bidirectionalS> DiGraph;
typedef boost::graph_traits<SubGraph>::vertex_descriptor vertex_t;
typedef boost::graph_traits<SubGraph>::edge_descriptor edge_t;

unordered_map<edge_t, double> P;

ifstream infile(prob_filename);
double p;
int u, v;
while (infile >> u >> v >> p) {
    P[make_pair(u, v)] = p;
}

但是，我不需要将一对作为键，而是将边缘描述符 edge_t。如何使用给定的两个值 u 和 v 创建边缘描述符。

Answer 1

From boost graph concepts

DirectedGraph digraph(V);
  {
    boost::graph_traits<DirectedGraph>::vertex_descriptor u, v;
    u = vertex(0, digraph); // read these instead 0,1 from from your file
    v = vertex(1, digraph);
    // populate graph
    add_edge(digraph, u, v, Weight(1.2)); // read weight (prob) instead from from your file

    boost::graph_traits<DirectedGraph>::edge_descriptor e;
    bool found;
    boost::tie(e, found) = edge(u, v, digraph);

    //use property map
    property_map<DirectedGraph, edge_weight_t>::type
      weight = get(edge_weight, digraph);

    cout << "weight[(u,v)] = " << get(weight, e) << endl;

  }