c++ - 在提升图形库中将颜色映射提供给深度优先搜索时遇到问题

Question

我正在尝试使用从特定顶点开始的深度优先搜索。为此，我需要提供一个访客和一张彩色 map 。
如果我不提供起始顶点，那么我也不需要提供颜色图，一切正常。但是，我没有找到不需要颜色贴图就可以接受起始顶点的签名。
我使用 C++ 17(Embarcadero C++ Builder)
这是代码:

    #include <stdio.h>
    #include <boost/graph/graph_traits.hpp>
    #include <boost/graph/adjacency_list.hpp>
    #include <boost/graph/breadth_first_search.hpp>
    #include <boost/graph/depth_first_search.hpp>
    #include <boost/graph/topological_sort.hpp>
    
    struct EdgeProps
    {
        int value;
    };
    
    struct VertexProps
    {
        int value;
    };
    
    struct cycle_detector : public boost::default_dfs_visitor
      {
        cycle_detector( bool& has_cycle)
          : _has_cycle(has_cycle) { }
    
        template <class Edge, class Graph>
        void back_edge(Edge, Graph&) {
          _has_cycle = true;
        }
      protected:
        bool& _has_cycle;
      };
    
    int _tmain(int argc, _TCHAR* argv[]) 
    {
        typedef boost::adjacency_list<boost::setS, boost::vecS, boost::bidirectionalS, VertexProps, EdgeProps> Graph;
        Graph g;
        auto v0 = boost::add_vertex(g);
        auto v1 = boost::add_vertex(g);
        auto v2 = boost::add_vertex(g);
        auto v3 = boost::add_vertex(g);
        auto v4 = boost::add_vertex(g);
    
        boost::add_edge(v0, v1, g);
        boost::add_edge(v0, v2, g);
        boost::add_edge(v0, v3, g);
        boost::add_edge(v2, v4, g);
        boost::add_edge(v3, v4, g);
    
        bool has_cycle = false;
    
        std::vector<boost::default_color_type> colors(boost::num_vertices(g));
        boost::iterator_property_map color_map(colors.begin(), boost::get(boost::vertex_index, g));
    
        boost::depth_first_search(g, boost::visitor(cycle_detector(has_cycle)), color_map, v0);
    
        return 0;
    }

我收到一连串提示访问者的错误消息。然而，如果我不提供 map 和起始顶点，那么一切都很好。
以下是消息:

bcc32c command line for "DFS.cpp"
  c:\program files (x86)\embarcadero\studio\21.0\bin\bcc32c.exe -cc1 -D _DEBUG -output-dir .\Win32\Debug -I D:\Study\Trees -I D:\Study\Trees -isystem 
  "c:\program files (x86)\embarcadero\studio\21.0\include" -isystem "c:\program files (x86)\embarcadero\studio\21.0\include\dinkumware64" -isystem 
  "c:\program files (x86)\embarcadero\studio\21.0\include\windows\crtl" -isystem "c:\program files (x86)\embarcadero\studio\21.0\include\windows\sdk" 
  -isystem "c:\program files (x86)\embarcadero\studio\21.0\include\windows\rtl" -isystem "c:\program files 
  (x86)\embarcadero\studio\21.0\include\windows\vcl" -isystem "c:\program files (x86)\embarcadero\studio\21.0\include\windows\fmx" -isystem 
  C:\Users\Public\Documents\Embarcadero\Studio\21.0\hpp\Win32 -isystem "c:\program files (x86)\embarcadero\studio\21.0\include\boost_1_70" -isystem 
  "D:\Icrfs\Components\TeeChart 2020.30\Compiled\Delphi27.win32\Include" -isystem "D:\ICRFS\Components\Orpheus Sydney\Win32\hpp" -isystem "c:\program 
  files (x86)\embarcadero\studio\21.0\include\boost_1_70\\BOOST" -isystem D:\ICRFS\Components\SimpleGraph\hpp -isystem 
  C:\Users\Public\Documents\Embarcadero\Studio\21.0\hpp\Win32 -debug-info-kind=standalone -fborland-extensions -nobuiltininc -nostdsysteminc -triple 
  i686-pc-windows-omf -emit-obj -mrelocation-model static -masm-verbose -ffunction-sections -fexceptions -fcxx-exceptions -fseh -mstack-alignment=16 
  -fno-spell-checking -fno-use-cxa-atexit -fno-threadsafe-statics -main-file-name DFS.cpp -x c++ -std=c++17 -O0 -fmath-errno -tC -tM -o 
  .\Win32\Debug\DFS.obj --auto-dependency-output -MT .\Win32\Debug\DFS.obj -include-pch .\Win32\Debug\TreesPCH1.pch DFS.cpp 
[bcc32c Error] depth_first_search.hpp(234): no member named 'initialize_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
  DFS.cpp(62): in instantiation of function template specialization 'boost::depth_first_search<boost::adjacency_list<boost::setS, boost::vecS, boost::bidirectionalS, VertexProps, EdgeProps, boost::no_property, boost::listS>, boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>, boost::iterator_property_map<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<boost::default_color_type> > >, boost::vec_adj_list_vertex_id_map<VertexProps, unsigned int>, boost::default_color_type, boost::default_color_type &> >' requested here
[bcc32c Error] depth_first_search.hpp(237): no member named 'start_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(245): no member named 'start_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(39): no member named 'initialize_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
  general.hpp(47): in instantiation of member function 'boost::DFSVisitorConcept<boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>, boost::adjacency_list<boost::setS, boost::vecS, boost::bidirectionalS, VertexProps, EdgeProps, boost::no_property, boost::listS> >::constraints' requested here
  depth_first_search.hpp(227): in instantiation of member function 'boost::concepts::constraint<boost::DFSVisitorConcept<boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>, boost::adjacency_list<boost::setS, boost::vecS, boost::bidirectionalS, VertexProps, EdgeProps, boost::no_property, boost::listS> > >::failed' requested here
  DFS.cpp(62): in instantiation of function template specialization 'boost::depth_first_search<boost::adjacency_list<boost::setS, boost::vecS, boost::bidirectionalS, VertexProps, EdgeProps, boost::no_property, boost::listS>, boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>, boost::iterator_property_map<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<boost::default_color_type> > >, boost::vec_adj_list_vertex_id_map<VertexProps, unsigned int>, boost::default_color_type, boost::default_color_type &> >' requested here
[bcc32c Error] depth_first_search.hpp(40): no member named 'start_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(41): no member named 'discover_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(42): no member named 'examine_edge' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(43): no member named 'tree_edge' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(44): no member named 'back_edge' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(45): no member named 'forward_or_cross_edge' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(47): no member named 'finish_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(134): no member named 'discover_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
  depth_first_search.hpp(238): in instantiation of function template specialization 'boost::detail::depth_first_visit_impl<boost::adjacency_list<boost::setS, boost::vecS, boost::bidirectionalS, VertexProps, EdgeProps, boost::no_property, boost::listS>, boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>, boost::iterator_property_map<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<boost::default_color_type> > >, boost::vec_adj_list_vertex_id_map<VertexProps, unsigned int>, boost::default_color_type, boost::default_color_type &>, boost::detail::nontruth2>' requested here
  DFS.cpp(62): in instantiation of function template specialization 'boost::depth_first_search<boost::adjacency_list<boost::setS, boost::vecS, boost::bidirectionalS, VertexProps, EdgeProps, boost::no_property, boost::listS>, boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>, boost::iterator_property_map<std::_Vector_iterator<std::_Vector_val<std::_Simple_types<boost::default_color_type> > >, boost::vec_adj_list_vertex_id_map<VertexProps, unsigned int>, boost::default_color_type, boost::default_color_type &> >' requested here
[bcc32c Error] depth_first_search.hpp(155): no member named 'examine_edge' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(158): no member named 'tree_edge' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(163): no member named 'discover_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
[bcc32c Error] depth_first_search.hpp(179): no member named 'finish_vertex' in 'boost::bgl_named_params<cycle_detector, boost::graph_visitor_t, boost::no_property>'
Failed
Elapsed time: 00:00:02.8

任何帮助将非常感激

Answer 1

将您的访客包裹在 boost::visitor 中你对 the named-parameter overload 感到困惑.只需传递访问者:

boost::depth_first_search(g, cycle_detector{has_cycle}, color_map, v0);

或 将所有参数作为命名参数传递:

boost::depth_first_search(g,
        boost::visitor(cycle_detector{has_cycle})
            .color_map(color_map)
            .root_vertex(v0));

Live On Coliru

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/breadth_first_search.hpp>
#include <boost/graph/depth_first_search.hpp>
#include <boost/graph/graph_traits.hpp>
#include <boost/graph/topological_sort.hpp>
#include <stdio.h>

#ifndef IHAVEASANECOMPILER_PLATFORM
    #define _tmain main
    #define _TCHAR char
#endif

struct EdgeProps {
    int value;
};

struct VertexProps {
    int value;
};

struct cycle_detector : boost::default_dfs_visitor {
    cycle_detector(bool& has_cycle) : _has_cycle(has_cycle) {}

    template <class Edge, class Graph> void back_edge(Edge, Graph&) {
        _has_cycle = true;
    }

    bool& _has_cycle;
};

int _tmain() {
    typedef boost::adjacency_list<boost::setS, boost::vecS,
                                  boost::bidirectionalS, VertexProps, EdgeProps>
          Graph;
    Graph g;
    auto v0 = boost::add_vertex(g);
    auto v1 = boost::add_vertex(g);
    auto v2 = boost::add_vertex(g);
    auto v3 = boost::add_vertex(g);
    auto v4 = boost::add_vertex(g);

    boost::add_edge(v0, v1, g);
    boost::add_edge(v0, v2, g);
    boost::add_edge(v0, v3, g);
    boost::add_edge(v2, v4, g);
    boost::add_edge(v3, v4, g);

    bool has_cycle = false;

    std::vector<boost::default_color_type> colors(boost::num_vertices(g));
    boost::iterator_property_map color_map(colors.begin(), boost::get(boost::vertex_index, g));

    boost::depth_first_search(g, cycle_detector{has_cycle}, color_map, v0);
}