Question

我有两个对象向量，我需要从它们制作树形结构。我们假设我们有vector <obj> parents和vector <obj> leaves。因此，vector <obj> parents的每个元素都有几个位于树末端的叶子。我正在做的是定义Vertex properties和Edges properties，如下所示，然后定义bidirectional graph：

struct VertexData
{
    std::string obj_name; // concatenation of labels
    std::string obj_class_num;
    int num;
    vector <int> segments_list;
    bool is_leaf=false;
};

struct EdgeData
{
    std::string edge_name;
    double confidence;
};

typedef boost::adjacency_list<boost::vecS, boost::vecS,
        boost::bidirectionalS,
        VertexData,
        boost::property<boost::edge_weight_t, double, EdgeData> > Graph;

Graph graph;

第一种方法：循环遍历vector <obj> leaves，对于每个成员，我找到了父级并创造了优势。然后为边和顶点指定属性。但是对于下一个叶子，我应该检查它是否已经在树中有一个父项，或者我应该为它的父项添加一个新的顶点。
第二种方法：我尝试过的另一件事是循环遍历vector <obj> parents，并为每个元素尝试制作它的叶子。但我不确定这样做的正确方法是什么。这是一个链接： adding custom vertices to a boost graph我尝试做同样但迭代。

为第一种方法添加的代码：

vector <class1> parents; // this has some objects of type class1
vector <class2> leaves; // this has some objects of type class2

/// declare the graph
typedef boost::adjacency_list<boost::vecS, boost::vecS,
        boost::bidirectionalS,
        VertexData,
        boost::property<boost::edge_weight_t, double, EdgeData> > Graph;

/// instantiate the graph
Graph graph;

typedef boost::graph_traits<Graph>::vertex_descriptor vertex_t;
typedef boost::graph_traits<Graph>::edge_descriptor edge_t;
vector<vertex_t> obj_vertices;
vector<string>   parents_labels_v;
bool parent_exist=false;


/// loop through leaves and make edges with associated parent
for (auto leaf: leaves) {

    int leaf_nr = leaf.Number;

    vertex_t v = boost::add_vertex(graph); // this is the leaf vertex
    graph[v].num     = leaf_nr;         // leaf number
    graph[v].is_leaf = true;
    /// access the parent label by leaf number
    string label1 = parents[leaf_nr].label;

    /// check if the parent already exist, using its label
    if(std::find(parents_labels_v.begin(), parents_labels_v.end(), label1)
       != parents_labels_v.end()){
        parent_exist = true;
    }else{
        parents_labels_v.push_back(label1);
    }

    if(parent_exist) {
        // find already_exist parent vertex to make the edge
        vertex_t u = ???  here i have problem
        // Create an edge connecting those two vertices
        edge_t e; bool b;
        boost::tie(e,b) = boost::add_edge(u,v,graph);
    } else{
        // if parent-vertex there is not, add it to the graph
        vertex_t u = boost::add_vertex(graph); // this is the parent vertex
        graph[u].obj_name = label1;
        graph[u].segments_list.push_back(leaf_nr);
        obj_vertices.push_back(u);

        // Create an edge connecting those two vertices
        edge_t e; bool b;
        boost::tie(e,b) = boost::add_edge(u,v,graph);
    }

}

使用BGL从矢量填充树

0 个答案: