Boost Graph Getting Adjacent Vertices

Question

I am working with a graphing using Boost library. The graph is defined as follows.

 typedef boost::adjacency_list<boost::setS,boost::setS,boost::undirectedS, uint32_t, float> AdjacencyList;

After creating the graph using appropriate data, in a separate function I want to print the adjacent_vertices of each vertex with their appropriate edge weight as computed in the beginning.

The creating part works well but when I want to extract adjacent vertices I dont get the values.

typedef boost::graph_traits<AdjacencyList>::adjacency_iterator AdjacencyIterator;
AdjacencyList::vertex_iterator i, end;
for (boost::tie(i, end) = boost::vertices(adjacency_list); i != end; i++) {
AdjacencyIterator ai, a_end; 
boost::tie(ai, a_end) = boost::adjacent_vertices( *i, adjacency_list);
  for (; ai != a_end; ai++) { 
      std::cout << *ai << "\t";
  }
 }

The Output I get are memory address in Hexademial number. How can I get vertex indices and the edge weight?

You're actually using two separate graphs there... You can't look for adjacent vertices for a vertex in another graph; What is your actual code? (That's ignoring the glaring syntax errors and missing declarations) — sehe
adjacency_list is of type AdjacencyList. It is the same graph but I just skipped all the other code. — kcc__
Sooo. What is supervoxel_adjacency_list? You know, it's not worth wasting time on ill-posed questions. — sehe
My apologies, that is the name given in my program but I deleted the supervoxel_ from the name to adjacency_list while writing the question — kcc__

sehe sehe · Accepted Answer · 2015-07-21T13:30:43

You should access the property bundles, either using the graph's operator[] with the vertex/edge descriptor, or using the property map:

Using the `operator[]`

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

typedef boost::adjacency_list<boost::setS,boost::setS,boost::undirectedS, uint32_t, float> AdjacencyList;
typedef boost::graph_traits<AdjacencyList>::adjacency_iterator AdjacencyIterator;

int main() {
    AdjacencyList adjacency_list;;

    boost::add_edge(
            boost::add_vertex(10, adjacency_list),
            boost::add_vertex(20, adjacency_list),
            1.5f,
            adjacency_list
        );

    boost::add_edge(
            boost::add_vertex(30, adjacency_list),
            boost::add_vertex(40, adjacency_list),
            2.5f,
            adjacency_list
        );

    AdjacencyList::vertex_iterator i, end;

    for (boost::tie(i, end) = boost::vertices(adjacency_list); i != end; i++) {
        AdjacencyIterator ai, a_end; 

        boost::tie(ai, a_end) = boost::adjacent_vertices(*i, adjacency_list);
        for (; ai != a_end; ai++) { 
            std::cout << adjacency_list[*ai] << "\t";
        }
    }
}

Output:

10  20  30  40

Using the property map:

boost::property_map<AdjacencyList, boost::vertex_bundle_t>::type pmap = boost::get(boost::vertex_bundle, adjacency_list);

Now you can use boost::get(pmap, vertex_descriptor1) to access the vertex property bundle

Boost Graph Getting Adjacent Vertices

1 Answers

Using the operator[]

Using the property map:

Using the `operator[]`