Usage of boost::graph isomorphism

Question

How do I specify boost::isomorphism_map when using adjacency_list<vecS, vecS, undirectedS>?

What I'm trying to complete is marked ?????????:

typedef adjacency_list<vecS, vecS, undirectedS> graph_t;
      graph_t g1(n), g2(n);

      add_edge(0, 1, g1); add_edge(1, 2, g1); 

      add_edge(9, 10, g2);  add_edge(10, 11, g2);  

      std::vector<graph_traits<graph_t>::vertex_descriptor> f(n);

      bool ret = isomorphism
        (g1, g2, isomorphism_map
         (make_iterator_property_map(f.begin(), ?????????, f[0])));

Answer 1

To make an iterator property-map, you need two arguments:

make_iterator_property_map( RAIter iter, ID id )

Drop your third argument.

The first you have: f.begin() is the random access iterator to the first element.

ID needs to be the vertex index map. In your case you can query it from the graph (because vecS results in a implicit vertex index):

Live On Coliru

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/isomorphism.hpp>
typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS> graph_t;

int main() {
    int n = 12;
    graph_t g1(n), g2(n);

    add_edge(0, 1, g1);
    add_edge(1, 2, g1);

    add_edge(9, 10, g2);
    add_edge(10, 11, g2);

    std::vector<graph_t::vertex_descriptor> f(n);

    bool ret = isomorphism(
            g1, g2,
            isomorphism_map(boost::make_iterator_property_map(f.begin(), boost::get(boost::vertex_index, g1)))
        );
}

Notes

Consider making a safe iterator map:

boost::make_safe_iterator_property_map(f.begin(), n, boost::get(boost::vertex_index, g1))

If you're not interested in safety (?!??) you can do a lot shorter:

bool ret = isomorphism(g1, g2, boost::isomorphism_map(f.data()));

This uses the vertex_index automatically.