Dijkstra最短路径与VertexList = ListS在boost图

Dijkstra Shortest Path with VertexList = ListS in boost graph

本文关键字：boost ListS 最短路径 VertexList Dijkstra      更新时间：2023-10-16

我对Boost图形很陌生。我试图适应一个例子，寻找Dijkstra最短路径算法使用VertexList = vecS。我将顶点容器更改为列表。我了解到，如果我们使用列表，我们必须提供自己的vertex_index才能使算法工作。

int main(int, char *[])
{
  typedef float Weight;
  typedef boost::property<boost::edge_weight_t, Weight> WeightProperty;
  typedef boost::property<boost::vertex_name_t, std::string> NameProperty;
  typedef boost::property<boost::vertex_index_t, int> IndexProperty;
  typedef boost::adjacency_list < boost::listS, boost::listS, boost::directedS,
  NameProperty, WeightProperty > Graph;
  typedef boost::graph_traits < Graph >::vertex_descriptor Vertex;
  typedef boost::graph_traits <Graph>::vertex_iterator Viter;
  typedef boost::property_map < Graph, boost::vertex_index_t >::type IndexMap;
  typedef boost::property_map < Graph, boost::vertex_name_t >::type NameMap;
  typedef boost::iterator_property_map < Vertex*, IndexMap, Vertex, Vertex& > PredecessorMap;
  typedef boost::iterator_property_map < Weight*, IndexMap, Weight, Weight& > DistanceMap;
  Graph g;

  Vertex v0 = boost::add_vertex(std::string("v0"), g);
  Vertex v1 = boost::add_vertex(std::string("v1"), g);
  Vertex v2 = boost::add_vertex(std::string("v2"), g);
  Vertex v3 = boost::add_vertex(std::string("v3"), g);
  Weight weight0 = 5;
  Weight weight1 = 3;
  Weight weight2 = 2;
  Weight weight3 = 4;
  boost::add_edge(v0, v1, weight0, g);
  boost::add_edge(v1, v3, weight1, g);
  boost::add_edge(v0, v2, weight2, g);
  boost::add_edge(v2, v3, weight3, g);

  std::vector<Vertex> predecessors(boost::num_vertices(g)); // To store parents
  std::vector<Weight> distances(boost::num_vertices(g)); // To store distances
  IndexMap indexMap; // = boost::get(boost::vertex_index, g);
  NameMap name;
  Viter i, iend;
 //Create our own vertex index. This is what I changed in the original code
    int c = 0;
  for (boost::tie(i, iend) = vertices(g); i != iend; ++i, ++c) {
       indexMap[*i] = c; // **Error points to this line**
       name[*i] = 'A' + c;
  }
PredecessorMap predecessorMap(&predecessors[0], indexMap);
DistanceMap distanceMap(&distances[0], indexMap);
boost::dijkstra_shortest_paths(g, v0,   boost::distance_map(distanceMap).predecessor_map(predecessorMap));

  // Extract a shortest path
  std::cout << std::endl;
  typedef std::vector<Graph::edge_descriptor> PathType;
  PathType path;
  Vertex v = v3; 
  for(Vertex u = predecessorMap[v]; 
  u != v; // Keep tracking the path until we get to the source
  v = u, u = predecessorMap[v]) // Set the current vertex to the current predecessor,     and the predecessor to one level up
  {
     std::pair<Graph::edge_descriptor, bool> edgePair = boost::edge(u, v, g);
    Graph::edge_descriptor edge = edgePair.first;
    path.push_back( edge );
  }
  // Write shortest path
  std::cout << "Shortest path from v0 to v3:" << std::endl;
  float totalDistance = 0;
  for(PathType::reverse_iterator pathIterator = path.rbegin(); pathIterator !=       path.rend(); ++pathIterator)
  {
    std::cout << name[boost::source(*pathIterator, g)] << " -> " <<     name[boost::target(*pathIterator, g)]
              << " = " << boost::get( boost::edge_weight, g, *pathIterator ) <<     std::endl;
  }
  std::cout << std::endl;
  std::cout << "Distance: " << distanceMap[v3] << std::endl;
  return EXIT_SUCCESS;
}

我得到以下错误:

/spvec.cpp:62:20:错误:' operator= '在' index '中没有匹配。boost::adj_list_vertex_property_map::operator[] [with Graph = boost::adjacency_list>， boost::property>， ValueType = boost::detail::error_property_not_found, Reference = boost::detail::error_property_not_found&， Tag = boost::vertex_index_t, boost::adj_list_vertex_property_map::key_type = void*](i.d d::_List_iterator<_Tp>::operator* with _Tp = void*， _Tp&= void*&) = c '

我确信我在创建自己的顶点索引时犯了一个错误。但我找不出问题到底是什么。有没有人对我做错了什么有一些建议…

BGL实际上有一个使用dijkstra_shortest_paths与listS/listS的例子，但它没有链接到HTML文档:http://www.boost.org/doc/libs/release/libs/graph/example/dijkstra-example-listS.cpp

错误信息试图告诉您(error: no match for ‘operator=’ in ‘index.boost::adj_list_vertex_property_map...ValueType = boost::detail::error_property_not_found...)的是vertex_index_t属性没有每个顶点存储，这是adj_list_vertex_property_map需要的。为了解决这个问题，你可以改变你的Graph typedef，包括vertex_index_t属性的逐顶点存储，或者使用一个"外部"属性映射，如associative_property_map。

dijkstra-example-listS.cpp的例子使用了改变图typedef的方法。要在代码中使用这种方法，您可以定义:

typedef boost::adjacency_list <boost::listS, boost::listS, boost::directedS,
  boost::property<boost::vertex_name_t, std::string, boost::property<boost::vertex_index_t, int> >,
  boost::property<boost::edge_weight_t, Weight> > Graph;

如果有人对解决方案感兴趣，按照前面的回答建议创建associative_property_map解决了这个问题:

   typedef std::map<vertex_desc, size_t>IndexMap;
   IndexMap mapIndex;
   boost::associative_property_map<IndexMap> propmapIndex(mapIndex);
   //indexing the vertices
     int i=0;
     BGL_FORALL_VERTICES(v, g, pGraph)
     {
        boost::put(propmapIndex, v, i++);
     }

然后将这个顶点索引映射作为命名参数传递给dijkstra_shortest_paths()调用。PS: BGL_FORALL_VERTICES()在

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