Apply algorithms considering a specific edge subset

Question

I've got a huge graph with typed edge (i.e. edge with a type property). Say

typedef adjacency_list<vecS, vecS, vertex_prop, edge_prop> Graph;  

The "type" of the edge is a member of edge_prop and has a value in {A,B,C,D},
I'd like to run the breadth first search algorithm considering only edges of type A or B.
How would you do that?

Answer 1

Because it's hard to find simple example mixing different topics of the BGL, I post below a full and working example using filtered_graph and bundled properties.:

#include <iostream>
#include <boost/graph/graph_utility.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/filtered_graph.hpp>

using namespace boost;

enum edge_type_e {
  A, B, C, D
};

class edge_property_c {
public:
  edge_property_c(void) : type_m(A) {}
  edge_property_c(edge_type_e type) : type_m(type) {}
  edge_type_e type_m;
};

typedef adjacency_list<vecS, vecS, undirectedS, no_property, edge_property_c> graph_t;
typedef graph_t::edge_descriptor edge_id_t;

class edge_predicate_c {
public:
  edge_predicate_c() : graph_m(0) {}
  edge_predicate_c(graph_t& graph) : graph_m(&graph) {}
  bool operator()(const edge_id_t& edge_id) const {
    edge_type_e type = (*graph_m)[edge_id].type_m;
    return (type == A || type == B);
  }
private:
  graph_t* graph_m;
};

int main() {
  enum { a, b, c, d, e, n };
  const char* name = "abcde";
  graph_t g(n);
  add_edge(a, b, edge_property_c(A), g);
  add_edge(a, c, edge_property_c(C), g);
  add_edge(c, d, edge_property_c(A), g);
  add_edge(c, e, edge_property_c(B), g);
  add_edge(d, b, edge_property_c(D), g);
  add_edge(e, c, edge_property_c(B), g);

  filtered_graph<graph_t, edge_predicate_c> fg(g, edge_predicate_c(g));

  std::cout << "edge set: ";
  print_edges(g, name);
  std::cout << "filtered edge set: ";
  print_edges(fg, name);

  return 0;
}

Answer 2

Finally I think the boost::graph way to do this is to use boost:filtered_graph and demo for usage

"The filtered_graph class template is an adaptor that creates a filtered view of a graph. The predicate function objects determine which edges and vertices of the original graph will show up in the filtered graph."

Thus, you can provide a edge (or vertex) filtering functor base on a property_map. In my case I'm using internal bundled properties. See Properties maps from bundled properties.