将 adjacency_list 复制到不同的 VertexList 和 EdgeList 模板

Question

我在将boost::adjacency_list<setS, setS, undirectedS, int, float> 转换或复制为boost::adjacency_list<vecS, vecS, undirectedS, int, float> 时遇到问题，因此我可以将其用于boost::connected_components。我无法从外部 API 控制 VertexList 和 EdgeList 模板参数为 boost::setS，所以我正在尝试解决这个问题。

小例子

#include <vector>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/connected_components.hpp>
#include <boost/graph/copy.hpp>

typedef boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, uint32_t, float> AdjacencyList;
typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, uint32_t, float> AdjacencyListWithVec;


typedef AdjacencyList::vertex_descriptor VertexID;


int main(int argc, char** argv)
{
    AdjacencyList adj;
    VertexID id_0 = boost::add_vertex(adj);
    VertexID id_1 = boost::add_vertex(adj);
    VertexID id_2 = boost::add_vertex(adj);
    VertexID id_3 = boost::add_vertex(adj);
    boost::add_edge(id_0, id_1, 1.0f, adj);
    boost::add_edge(id_2, id_3, 2.0f, adj);

    AdjacencyListWithVec adj_vec;
  
    boost::copy_graph(adj, adj_vec); // won't compile
  
    std::vector<uint32_t> component(4);
    size_t num_components = boost::connected_components (adj_vec, &component[0]);
  
}

g++ 错误被截断

/usr/include/boost/graph/detail/adjacency_list.hpp: In instantiation of 'struct boost::adj_list_any_vertex_pa::bind_<boost::vertex_index_t, boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>, int>':
/usr/include/boost/graph/detail/adjacency_list.hpp:2613:12:   required from 'struct boost::detail::adj_list_choose_vertex_pa<boost::vertex_index_t, boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>, int>'
/usr/include/boost/graph/detail/adjacency_list.hpp:2750:12:   required from 'struct boost::adj_list_vertex_property_selector::bind_<boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>, int, boost::vertex_index_t>'
/usr/include/boost/graph/properties.hpp:201:12:   required from 'struct boost::detail::vertex_property_map<boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>, boost::vertex_index_t>'
/usr/include/boost/graph/properties.hpp:212:10:   required from 'struct boost::property_map<boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>, boost::vertex_index_t, void>'
/usr/include/boost/graph/detail/adjacency_list.hpp:1733:5:   required by substitution of 'template<class Config, class Base, class Property> typename boost::property_map<typename Config::graph_type, Property>::const_type boost::get(Property, const boost::adj_list_helper<Config, Base>&) [with Config = boost::detail::adj_list_gen<boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>, boost::setS, boost::setS, boost::undirectedS, int, float, boost::no_property, boost::listS>::config; Base = boost::undirected_graph_helper<boost::detail::adj_list_gen<boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>, boost::setS, boost::setS, boost::undirectedS, int, float, boost::no_property, boost::listS>::config>; Property = boost::vertex_index_t]'
/usr/include/boost/graph/copy.hpp:353:38:   required from 'void boost::copy_graph(const VertexListGraph&, MutableGraph&) [with VertexListGraph = boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>; MutableGraph = boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, int, float>]'
/my/file/and/line/num:   required from here
/usr/include/boost/graph/detail/adjacency_list.hpp:2543:29: error: forming reference to void
         typedef value_type& reference;
                             ^~~~~~~~~
/usr/include/boost/graph/detail/adjacency_list.hpp:2544:35: error: forming reference to void
         typedef const value_type& const_reference;
                                   ^~~~~~~~~~~~~~~
/usr/include/boost/graph/detail/adjacency_list.hpp:2547:47: error: forming reference to void
           <Graph, value_type, reference, Tag> type;
                                               ^~~~
/usr/include/boost/graph/detail/adjacency_list.hpp:2549:53: error: forming reference to void
           <Graph, value_type, const_reference, Tag> const_type;
                                                     ^~~~~~~~~~
...

In file included from/my/file:5:0:
/usr/include/boost/graph/copy.hpp: In instantiation of 'void boost::copy_graph(const VertexListGraph&, MutableGraph&) [with VertexListGraph = boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>; MutableGraph = boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, int, float>]':
/my/file/and/line/num:   required from here
/usr/include/boost/graph/copy.hpp:353:38: error: no matching function for call to 'get(boost::vertex_index_t, const boost::adjacency_list<boost::setS, boost::setS, boost::undirectedS, int, float>&)'
                                   get(vertex_index, g_in), orig2copy[0]),
                                   ~~~^~~~~~~~~~~~~~~~~~~~

Answer 1

未指定顶点映射。创建一个很容易：

std::map<AdjacencyList::vertex_descriptor, int> index;
for (auto v : boost::make_iterator_range(boost::vertices(adj))) {
    index.insert(std::make_pair(v, index.size()));
}

AdjacencyListWithVec adj_vec;
boost::copy_graph(adj, adj_vec, boost::vertex_index_map(boost::make_assoc_property_map(index)));

Answer 2

来自documentation to boost::copy_graph：

命名参数

[…]

输入：vertex_index_map(VertexIndexMap i_map)

顶点索引映射类型必须是Readable Property Map的模型，并且必须将G的顶点描述符映射到半开范围[0,num_vertices(G))内的整数。

默认值：get(vertex_index, G)。
注意：如果使用此默认值，请确保您的图表具有内部 vertex_index 属性。例如，adjacency_list 和 VertexList=listS 没有内部 vertex_index 属性。

查看documentation for adjacency_list，我们看到：

如果图的VertexList 是vecS，则图具有通过vertex_index_t 属性的属性映射访问的内置顶点索引。

换句话说，您的限制因素是替代顶点列表表示不能很好地与默认顶点索引图配合使用。边缘列表表示不受影响。实际上，仅将setS 用于OutEdgeList 工作得很好，即以下工作：

typedef boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS, uint32_t, float> AdjacencyListWithVec;

如果你的VertexList必须是setS，那么你必须提供你自己的顶点索引图来处理它。很遗憾，我无法帮助您，但以下相关的 SO 问题可能会对您有所帮助：

• Dijkstra Shortest Path with VertexList = ListS in boost graph
• BGL dijkstra_shortest_path algorithm method does not accept my color map exterior property