Re: [Boost-users] [BGL] Problem with color maps for undirected_dfs_visit

On Thu, 2003-11-13 at 17:09, Jeremy Siek wrote:

Hi Tarjei,

You need to initialize the edge index property map (only the vertex index map is automatically initialized, and then only for VertexList=vecS).

Hmm, ok, but I still don't quite understand. I thought that initializing the std::vector holding the colors was sufficient...? To my understanding an iterator_property_map is just a property map which iterates through some other container (that can provide a RandomAccessIterator) actually holding the properties? Obviously there's some connection I don't quite get here... I also don't quite understand the EColorValue uv_color = get(edge_color, *ei); call in undir_dfv_impl. It asks for the edge_color at the edge_descriptor *ei, but from where? Anyway, I don't really even need an edge_index property here (or do I?), it was more or less to try to get this working. Could you please provide a bit more detailed description of how I should initialize the edge colormap properly? Thanks a lot, Tarjei

On Thu, 13 Nov 2003, Tarjei Knapstad wrote:

tarjei> I'm trying to implement a DFS visitor and using it with tarjei> undirected_dfs_visit, but I'm getting a segfault which relates to the tarjei> edge color map. I've made the following test app for illustration: tarjei> tarjei> **************** START CODE **************** tarjei> tarjei> #include <vector> tarjei> #include tarjei> #include tarjei> tarjei> using namespace boost; tarjei> tarjei> struct Types tarjei> { tarjei> typedef adjacency_list property, tarjei> property property > > GraphType; tarjei> tarjei> typedef std::vector ColorVec; tarjei> typedef color_traits Color; tarjei> }; tarjei> tarjei> int main() tarjei> { tarjei> Types::GraphType g(6); tarjei> tarjei> add_edge(0,1,g); tarjei> add_edge(1,2,g); tarjei> add_edge(2,3,g); tarjei> add_edge(2,4,g); tarjei> add_edge(4,5,g); tarjei> tarjei> Types::ColorVec v_colors(num_vertices(g), Types::Color::white()); tarjei> Types::ColorVec e_colors(num_edges(g), Types::Color::white()); tarjei> tarjei> default_dfs_visitor visitor; tarjei> undirected_depth_first_visit(g, 0, visitor, tarjei> make_iterator_property_map(&v_colors[0], tarjei> get(vertex_index, g)), tarjei> make_iterator_property_map(&e_colors[0], tarjei> get(edge_index, g))); tarjei> }; tarjei> tarjei> **************** END CODE **************** tarjei> tarjei> The code crashes in undirected_dfs.hpp line 73 the first time it's tarjei> trying to access a color from the edge color map: tarjei> tarjei> EColorValue uv_color = get(edge_color, *ei); tarjei> tarjei> Valgrind turns up a lot of illegal reads/writes to the edge_color_map as tarjei> well, so I'm guessing that I've screwed up on the colormap creation. tarjei> Could anyone point out my error? Also, is this an error that could be tarjei> caught compile time by adding some sort of concept check? tarjei> tarjei> Thanks in advance for any help! tarjei> tarjei> Regards, tarjei> -- tarjei> Tarjei tarjei> tarjei> tarjei> _______________________________________________ tarjei> Boost-users mailing list tarjei> Boost-users@lists.boost.org tarjei> http://lists.boost.org/mailman/listinfo.cgi/boost-users tarjei>