c++ - Boost图在子图中找到边

Question

有一个图 G0 和子图 G1...G7，我想在子图 G1...G7 的集合中找到 G7 的出现，在这种特殊情况下，输出应该是 G7 在 5 中， G7 在 7 但它不起作用，输出是 G7 在 4 中， G7在6， G7 在 7 中。 我真的不明白错误可能在哪里。(也许是循环)

 #include < boost/config.hpp >

 #include < iostream >

 #include < boost/graph/subgraph.hpp >

 #include < boost/graph/adjacency_list.hpp >

 #include < boost/graph/graph_utility.hpp >

 #include < boost/graph/lookup_edge.hpp >


using namespace boost;

typedef subgraph< adjacency_list < vecS, vecS, directedS,

property < vertex_color_t, int > , property<edge_index_t, int> > > Graph;


int threshold = 3;
int size_of_database = 7;


int main(int,char*[])

{

    const int N = 6;
    Graph G0(N);
    enum { A, B, C, D, E, F};     // for conveniently refering to vertices in G0

    Graph& G1 = G0.create_subgraph();
    Graph& G2 = G0.create_subgraph();
    Graph& G3 = G0.create_subgraph();
    Graph& G4 = G0.create_subgraph();
    Graph& G5 = G0.create_subgraph();
    Graph& G6 = G0.create_subgraph();
    Graph& G7 = G0.create_subgraph();


    enum { A1, B1, C1 };   // for conveniently refering to vertices in G1
    enum { A2, B2 };    // for conveniently refering to vertices in G2
    enum { A3, B3 };
    enum { A4, B4, C4 };
    enum { A5, B5 };
    enum { A6, B6, C6 };
    enum { A7, B7 };

    add_vertex(C, G1); // global vertex C becomes local A1 for G1
    add_vertex(E, G1); // global vertex E becomes local B1 for G1
    add_vertex(F, G1); // global vertex F becomes local C1 for G1

    add_vertex(A, G2); // global vertex A becomes local A1 for G2
    add_vertex(B, G2); // global vertex B becomes local B1 for G2

    add_vertex(B, G3); // ...-||-...
    add_vertex(C, G3);

    add_vertex(A, G4);
    add_vertex(B, G4);
    add_vertex(E, G4);

    add_vertex(F, G5);
    add_vertex(D, G5);

    add_vertex(B, G6);
    add_vertex(D, G6);
    add_vertex(E, G6);

    add_vertex(F, G7);
    add_vertex(D, G7);

    add_edge(A, B, G0);
    add_edge(B, C, G0);
    add_edge(B, D, G0);
    add_edge(E, B, G0);
    add_edge(E, F, G0);
    add_edge(F, D, G0);

    add_edge(F, C, G1); // (A1,C1) is subgraph G1 local indices for (C,F).

    Graph::children_iterator ci, ci_end;
    Graph::edge_iterator ei, ei_end;

    int nj = 0;
    int g_n= 1;

    for (tie(ci, ci_end) = G0.children(); ci != ci_end; ++ci){

        for (tie(ei, ei_end) = edges(G7); ei != ei_end; ++ei){

            if( edge(G7.local_to_global(source(*ei,G7)), G7.local_to_global(target(*ei, G7)), *ci).second ) nj++;
        };
        if(nj == num_edges(G7)) std::cout<<"G7 is in"<<g_n<<std::endl;
        nj = 0;
        g_n++;
    };

    std::cout << "G0:" << std::endl;
    print_graph(G0, get(vertex_index, G0));
    print_edges2(G0, get(vertex_index, G0), get(edge_index, G0));
    std::cout << std::endl;

    int num = 1;
    for (boost::tie(ci, ci_end) = G0.children(); ci != ci_end; ++ci) {
        std::cout << "G" << num++ << ":" << std::endl;
        print_graph(*ci, get(vertex_index, *ci));
        print_edges2(*ci, get(vertex_index, *ci),get(edge_index, *ci));
        std::cout << std::endl;
    }



    return 0;
}

Answer 1

我想你想统计 G7 中包含边的子图的数量。

线

if (edge(G7.local_to_global(source(*ei, G7)), G7.local_to_global(target(*ei, G7)), *ci).second)

似乎是错误的，因为它使用全局顶点 ID 在 *ci 中查找边，这是它的任何子图。

doc

Each subgraph has its own vertex and edge descriptors, which we call local descriptors. We refer to root graph's vertex and edge descriptors as the global descriptors

这会更接近您的意图:

auto gs = G7.local_to_global(source(*ei, G7));
auto gt = G7.local_to_global(target(*ei, G7));

auto ls = ci->global_to_local(gs);
auto lt = ci->global_to_local(gt);

std::cout << "global (" << gs << "," << gt << ") local (" << ls << "," << gt << ")\n";

if (edge(ls, lt, *ci).second)
    nj++;

但是，global_to_local 断言顶点必须在子图中。所以真正的解决办法是

auto gs = G7.local_to_global(source(*ei, G7));
auto gt = G7.local_to_global(target(*ei, G7));
std::cout << "global (" << gs << "," << gt << ")\n";

auto ls = ci->find_vertex(gs);
auto lt = ci->find_vertex(gt);

if (ls.second && lt.second) {
    std::cout << "global (" << gs << "," << gt << ") local (" << ls.first << "," << lt.first << ")\n";

    if (edge(ls.first, lt.first, *ci).second)
        nj++;
}

---

演示

稍微重构样式:

Live On Coliru

#include <boost/config.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graph_utility.hpp>
#include <boost/graph/lookup_edge.hpp>
#include <boost/graph/subgraph.hpp>
#include <iostream>

using namespace boost;

typedef subgraph<adjacency_list<vecS, vecS, directedS, property<vertex_color_t, int>, property<edge_index_t, int>>>
    Graph;

int constexpr threshold = 3;
int constexpr size_of_database = 7;

template <typename G>
bool is_subgraph_present(G const& g, G const& other) {
    Graph::edge_iterator ei, ei_end;
    unsigned nj = 0;
    for (tie(ei, ei_end) = edges(g); ei != ei_end; ++ei) {

        auto gs = g.local_to_global(source(*ei, g));
        auto gt = g.local_to_global(target(*ei, g));
        //std::cout << "global (" << gs << "," << gt << ")\n";

        auto ls = other.find_vertex(gs);
        auto lt = other.find_vertex(gt);

        if (ls.second && lt.second) {
            //std::cout << "global (" << gs << "," << gt << ") local (" << ls.first << "," << lt.first << ")\n";

            if (edge(ls.first, lt.first, other).second)
                nj++;
        }
    }
    return nj == num_edges(g);
}


int main() {
    const int N = 6;
    enum { A, B, C, D, E, F }; // for conveniently refering to vertices in G0

    Graph G0(N);
    Graph& G1 = G0.create_subgraph();
    Graph& G2 = G0.create_subgraph();
    Graph& G3 = G0.create_subgraph();
    Graph& G4 = G0.create_subgraph();
    Graph& G5 = G0.create_subgraph();
    Graph& G6 = G0.create_subgraph();
    Graph& G7 = G0.create_subgraph();

    enum { A1, B1, C1 }; // for conveniently refering to vertices in G1
    enum { A2, B2 };     // for conveniently refering to vertices in G2
    enum { A3, B3 };
    enum { A4, B4, C4 };
    enum { A5, B5 };
    enum { A6, B6, C6 };
    enum { A7, B7 };

    add_vertex(C, G1); // global vertex C becomes local A1 for G1
    add_vertex(E, G1); // global vertex E becomes local B1 for G1
    add_vertex(F, G1); // global vertex F becomes local C1 for G1

    add_vertex(A, G2); // global vertex A becomes local A1 for G2
    add_vertex(B, G2); // global vertex B becomes local B1 for G2

    add_vertex(B, G3); // ...-||-...
    add_vertex(C, G3);

    add_vertex(A, G4);
    add_vertex(B, G4);
    add_vertex(E, G4);

    add_vertex(F, G5);
    add_vertex(D, G5);

    add_vertex(B, G6);
    add_vertex(D, G6);
    add_vertex(E, G6);

    add_vertex(F, G7);
    add_vertex(D, G7);

    add_edge(A, B, G0);
    add_edge(B, C, G0);
    add_edge(B, D, G0);
    add_edge(E, B, G0);
    add_edge(E, F, G0);
    add_edge(F, D, G0);

    //add_edge(F, C, G1); // (A1,C1) is subgraph G1 local indices for (C,F).

    Graph::children_iterator ci, ci_end;

    int g_n = 1;

    for (tie(ci, ci_end) = G0.children(); ci != ci_end; ++ci) {
        if (is_subgraph_present(G7, *ci)) {
            std::cout << "G7 is in G" << g_n << std::endl;
        }
        g_n++;
    }

    std::cout << "G0:" << std::endl;
    print_graph(G0, get(vertex_index, G0));
    print_edges2(G0, get(vertex_index, G0), get(edge_index, G0));
    std::cout << std::endl;

    int num = 1;
    for (boost::tie(ci, ci_end) = G0.children(); ci != ci_end; ++ci) {
        std::cout << "G" << num++ << ":" << std::endl;
        print_graph(*ci, get(vertex_index, *ci));
        print_edges2(*ci, get(vertex_index, *ci), get(edge_index, *ci));
        std::cout << std::endl;
    }
}

哪个打印

7 is in G5
G7 is in G7
G0:
0 --> 1 
1 --> 2 3 
2 --> 
3 --> 
4 --> 1 5 
5 --> 3 
0(0,1) 1(1,2) 2(1,3) 3(4,1) 4(4,5) 5(5,3) 

G1:
0 --> 
1 --> 2 
2 --> 
4(1,2) 

G2:
0 --> 1 
1 --> 
0(0,1) 

G3:
0 --> 1 
1 --> 
1(0,1) 

G4:
0 --> 1 
1 --> 
2 --> 1 
0(0,1) 3(2,1) 

G5:
0 --> 1 
1 --> 
5(0,1) 

G6:
0 --> 1 
1 --> 
2 --> 0 
2(0,1) 3(2,0) 

G7:
0 --> 1 
1 --> 
5(0,1)