我对Boost图很新.我试图调整一个例子找到使用VertexList = vecS的Dijkstra最短路径算法.我将顶点容器更改为ListS.我了解到,如果我们使用listS,我们必须提供我们自己的vertex_index来使算法工作.
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*,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,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;
}
我收到以下错误：
在/ index = = 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.std :: _ List_iterator< _Tp> :: with _Tp = void *,_Tp& = void *&)= c’
我确定我在创建自己的顶点索引时犯了一个错误.但究竟究竟是什么问题.有人对我做错了什么有一些建议吗
解决方法
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
这个错误信息正在尝试告诉你(错误：在’index.boost :: adj_list_vertex_property_map …中的’operator =’不匹配… ValueType = boost :: detail :: error_property_not_found …)是没有per- vertex_index_t属性的顶点存储,这是adj_list_vertex_property_map需要的.要解决这个问题,您可以更改Graph typedef以包含vertex_index_t属性的每顶点存储,也可以使用“external”属性映射(例如,associative_property_map).
dijkstra-example-listS.cpp示例使用更改图形typedef的方法.要在代码中使用此方法,您可以定义：
typedef boost::adjacency_list <boost::listS,boost::property<boost::vertex_name_t,std::string,boost::property<boost::vertex_index_t,int> >,boost::property<boost::edge_weight_t,Weight> > Graph;
