Re: [Boost-users] [BGL] johnson_all_pairs_shortest problem compiling

Hi Val, Thanks for your email! On Apr 4, 2004, at 10:39 AM, Val Samko wrote:

Hi,

Why doesn't the following code compile (VC++ 7.1, g++ 3.3.3, boost 1.31.0) ? ====================================================================== #include #include int main() { using namespace boost; typedef adjacency_list

boost::property

boost::property >

...

Graph; Graph g; int distance_matrix[100][100]; johnson_all_pairs_shortest_paths(g, distance_matrix); } ======================================================================

You've specified edge_weight_t as a vertex property. Instead you should have adjacency_list, property > also, note that since you've got VertexList=vecS, there is a built-in vertex index, so you should instead just have adjacency_list >

but it compiles, if we pass the edge weight map (composed from std::map) as a named parameter to johnson_all_pairs_shortest_paths ?

Also, why do johnson_all_pairs_shortest_paths(g, distance_matrix); and johnson_all_pairs_shortest_paths(g, distance_matrix, weight_map(get(vertex_index, g))); produce completely different compile time errors?

Because they are different errors. The second error is that get(vertex_index, g) does not return an edge weight map, which is what weight_map() is expecting.

Finally, is it possible to use johnson_all_pairs_shortest_paths with adjacency_list ? According to the documentation, this should be possible, but this just does not compile.

It is suppose to work... There were some bugs in johnson's with respect to this. I've checked in fixes. Also, with mapS you will need to specify vertex_index_t as an internal vertex property map of the adjacency_list. Cheers, Jeremy _______________________________________________ Jeremy Siek http://www.osl.iu.edu/~jsiek Ph.D. Student, Indiana University Bloomington Graduating in August 2004 and looking for work C++ Booster (http://www.boost.org) _______________________________________________