I'm trying to do some statistics with graphs (comparing 2 graphs). But have a problem when I compare the edges.
So, I create two graphs with some edges and then some templates for the vertices and edges operations. For the vertices it's working apperently well, but for the edges it's not working properly.
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/reverse_graph.hpp>
#include <boost/graph/iteration_macros.hpp>
#include <boost/graph/graph_utility.hpp>
typedef boost::adjacency_list < boost::vecS, boost::vecS,
boost::undirectedS > Graph;
template <typename T> std::set<T> operator-(const std::set<T>& a,
const std::set<T>& b)
{
std::set<T> r;
std::set_difference(
a.begin(), a.end(),
b.begin(), b.end(),
std::inserter(r, r.end()));
return r;
}
template <typename T> std::set<T> operator/(const std::set<T>& a,
const std::set<T>& b)
{
std::set<T> r;
std::set_intersection(
a.begin(), a.end(),
b.begin(), b.end(),
std::inserter(r, r.end()));
return r;
}
void compare(const Graph& a, const Graph& b)
{
std::set<Graph::vertex_descriptor > av, bv, samev, extrav, missingv;
std::set<Graph::edge_descriptor> ae, be, re, samee, extrae, missinge;
BGL_FORALL_VERTICES_T(v, a, Graph) av.insert(v);
BGL_FORALL_VERTICES_T(v, b, Graph) bv.insert(v);
samev = (av / bv);
extrav = (bv - av);
missingv = (av - bv);
BGL_FORALL_EDGES_T(e, a, Graph) ae.insert(e);
BGL_FORALL_EDGES_T(e, b, Graph) be.insert(e);
samee = (ae / be);
extrae = (be - ae);
missinge = (ae - be);
// TODO(silgon): reverse_graph
// boost::reverse_graph<Graph> r(b);
// BGL_FORALL_EDGES_T(e, r, Graph) re.insert(e);
std::cout << "---- Vertices ----\n"
<< "same: " << samev.size() << std::endl
<< "extra: " << extrav.size() << std::endl
<< "missing: " << missingv.size() << std::endl;
std::cout << "---- Edges ----\n"
<< "same: " << samee.size() << std::endl
<< "extra: " << extrae.size() << std::endl
<< "missing: " << missinge.size() << std::endl;
}
int main()
{
Graph a;
{
boost::graph_traits<Graph>::vertex_descriptor v, u, y;
u = boost::vertex(1, a);
v = boost::vertex(2, a);
y = boost::vertex(3, a);
boost::add_edge(u, v, a);
}
Graph b;
{
boost::graph_traits<Graph>::vertex_descriptor v, u, y;
u = vertex(1, b);
v = vertex(2, b);
y = vertex(3, b);
boost::add_edge(u, v, b);
boost::add_edge(y, v, b);
}
const char* name = "123456";
std::cout << "---Graph1---" << "\n";
boost::print_graph(a);
std::cout << "Edges: ";
boost::print_edges(a,name);
std::cout << "---Graph2---" << "\n";
boost::print_graph(b);
std::cout << "Edges: ";
boost::print_edges(b,name);
compare(a,b);
}
As for the result of the program it's the following:
---Graph1---
0 <-->
1 <--> 2
2 <--> 1
Edges: (2,3)
---Graph2---
0 <-->
1 <--> 2
2 <--> 1 3
3 <--> 2
Edges: (2,3) (4,3)
---- Vertices ----
same: 3
extra: 1
missing: 0
---- Edges ----
same: 0
extra: 2
missing: 1
You can see that one of the edges is the same (2,3), but when doing the operations it's not taking it into account so in the results it say same:0, and either extra or missing results are not working.
As a temporary solution to my problem, instead of:
std::set<Graph::edge_descriptor> ae
BGL_FORALL_EDGES_T(e, a, Graph) ae.insert(e)
I did the following code for edges.
std::set<std::pair<unsigned long, unsigned long> > ae;
BGL_FORALL_EDGES_T(e, ga, Graph) gae.insert(std::make_pair(e.m_source,
e.m_target));
The problem is that the edges of boost graph have the "m_eproperty" which I don't really know why is there, and it contains values like 0x125d0c0. Then I created a pair based on the source and the target of an edge and then I evaluated the same way as above (with the templates).