我试图从图形中复制边缘并将其添加到另一个图形（包含所有顶点和属性），我做了类似的事情：
if (!dataG.empty())
{
auto const& gr = dataG.front(); // firslt graph in G_list
auto ep = edges(gr).first; //first edge in gr
vertex_t from = source(*ep, gr);
vertex_t to = target(*ep, gr);
boost::property_map<Graph, int VertexProperties::*>::type idmap = boost::get(&VertexProperties::id, testg);
boost::property_map<Graph, int VertexProperties::*>::type labelmap = boost::get(&VertexProperties::label, testg);
idmap[from] = gr[from].id;
labelmap[from] = gr[from].label;
boost::add_vertex(VertexProperties(idmap[from], labelmap[from]), testg);
idmap[to] = gr[to].id;
labelmap[to] = gr[to].label;
boost::add_vertex(VertexProperties(idmap[to], labelmap[to]), testg);
boost::add_edge(from, to, gr[*ep], testg);
}
我收到了这个错误：
segmentation error core dumped
答案 0 :(得分：2)
您想要插入边缘，以便自动调整顶点数量以适应边缘的源和目标。
然后，只需按其包复制顶点属性，无需插入特定于成员的地图（当您想要将特定属性传递给例如算法时，这些属性很有用。）
这是简化版：
auto const& gr = dataG.front(); // firslt graph in G_list
auto ep = edges(gr).first; // first edge in gr
vertex_t from = source(*ep, gr);
vertex_t to = target(*ep, gr);
Graph::edge_descriptor copied_edge = boost::add_edge(from, to, gr[*ep], testg).first;
testg[source(copied_edge, testg)] = gr[from];
testg[target(copied_edge, testg)] = gr[to];
实时样本：
<强> Live On Coliru
#include <boost/graph/adjacency_list.hpp>
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
#include <ctime>
/*********************************************/
// vertex
struct VertexProperties {
int id;
int label;
VertexProperties(unsigned i = 0, unsigned l = 0) : id(i), label(l) {}
};
// edge
struct EdgeProperties {
unsigned id;
unsigned label;
EdgeProperties(unsigned i = 0, unsigned l = 0) : id(i), label(l) {}
};
// Graph
struct GraphProperties {
unsigned id;
unsigned label;
GraphProperties(unsigned i = 0, unsigned l = 0) : id(i), label(l) {}
};
// adjency list
typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::directedS, VertexProperties, EdgeProperties, GraphProperties>
Graph;
// descriptors
typedef boost::graph_traits<Graph>::vertex_descriptor vertex_t;
typedef std::pair<boost::graph_traits<Graph>::edge_descriptor, bool> edge_t;
// iterators
typedef boost::graph_traits<Graph>::vertex_iterator vertex_iter;
typedef boost::graph_traits<Graph>::edge_iterator edge_iter;
int main()
{
clock_t start = std::clock();
std::vector<Graph> dataG;
std::ifstream file_reader("5.txt"); // flux d'entrée pour opérer sur les fichiers.
// ifstream * file_reader= new ifstream("60.txt" ); //flux d'entrée pour opérer sur les fichiers.
std::string line;
while (std::getline(file_reader, line)) { // getline reads characters from an input stream and places them into a string
char lineType;
std::stringstream ss(line); // use a string buffer that contains a sequence of characters.
if (ss >> lineType)
switch (lineType) {
case 't': {
char diez;
unsigned gid;
if (ss >> diez >> gid) {
dataG.emplace_back(GraphProperties(gid, gid));
} else
throw std::runtime_error("Error parsing '" + line + "'");
} break;
case 'v': {
assert(!dataG.empty());
int vId, vLabel;
if (ss >> vId >> vLabel) {
boost::add_vertex(VertexProperties(vId, vLabel), dataG.back());
} else
throw std::runtime_error("Error parsing '" + line + "'");
} break;
case 'e': {
assert(!dataG.empty());
int fromId, toId, vLabel;
if (ss >> fromId >> toId >> vLabel) {
// Note that the EdgeProperty.id doesn't make sense with your input data
// as it only contains [vertexFrom vertexTo edgeData]
boost::add_edge(fromId, toId, EdgeProperties(vLabel, vLabel), dataG.back());
} else
throw std::runtime_error("Error parsing '" + line + "'");
} break;
}
else {
// ignoring empty line
}
}
Graph testg;
if (!dataG.empty()) {
auto const& gr = dataG.front(); // firslt graph in G_list
auto ep = edges(gr).first; // first edge in gr
vertex_t from = source(*ep, gr);
vertex_t to = target(*ep, gr);
Graph::edge_descriptor copied_edge = boost::add_edge(from, to, gr[*ep], testg).first;
testg[source(copied_edge, testg)] = gr[from];
testg[target(copied_edge, testg)] = gr[to];
}
typedef std::pair<edge_iter, edge_iter> edge_pair;
// int c = 0; //compteur de dataG
//++c;
std::cout << "Graph contains " << num_vertices(testg) << " vertices, and " << num_edges(testg) << " edges" << std::endl;
// Vertex list
std::cout << " Vertex list: " << std::endl;
for (size_t i = 0; i < num_vertices(testg); ++i) // size_t vertice number in the graph
{
std::cout << " v[" << i << "] ID: " << testg[i].id << ", Label: " << testg[i].label << std::endl;
}
// Edge list
std::cout << " Edge list: " << std::endl;
edge_pair ep;
for (ep = edges(testg); ep.first != ep.second; ++ep.first) // ep edge number
{
vertex_t from = source(*ep.first, testg);
vertex_t to = target(*ep.first, testg);
edge_t edg = edge(from, to, testg);
std::cout << " e[" << testg[from].id << "," << testg[to].id << "] ID: " << testg[edg.first].id
<< " , Label: " << testg[edg.first].label << std::endl;
}
std::cout << std::endl;
std::cout << "TIME: " << (std::clock() - start) / (double)CLOCKS_PER_SEC << "s" << std::endl; // fin du programme.
}
打印
INPUT
Graph contains 2 vertices, and 1 edges
Vertex list:
v[0] ID: 0, Label: 0
v[1] ID: 1, Label: 3
Edge list:
e[0,1] ID: 10 , Label: 10
TIME: 0s