Re: [Boost-users] BGL - color map assertion failed

On Sun, 27 Feb 2011, Krisztian Sinka wrote:

Hi,

I have the following code using Boost Graph Library to use the breadth-first-search:

-------- code start --------

template<typename T> class MyVisitor : public boost::default_bfs_visitor{ public: MyVisitor(T& d): boost::default_bfs_visitor(),d_(d) {}; template void tree_edge(E e,const G& g) const { typedef typename boost::graph_traits<G>::vertex_descriptor VD;

VD u = boost::source(e,g); VD v = boost::target(e,g);

d_[u].parent_ = v; }; private: T& d_; }; ... typedef boost::adjacency_listboost::vertex_name_t,IndexT , boost::propertyboost::edge_name_t,IndexT > GraphT; ... typedef boost::graph_traits<GraphT>::vertex_descriptor VD; ... struct DataMap { DataMap(VD p):parent_(p),distance_(0){}; DataMap():parent_(0),distance_(0){}; VD parent_; int distance_; }; ... typedef std::vector<DataMap> VisitedT; typedef VisitedT::iterator VisitedIterT;

// Graph g properly initialized here

VisitedT visited(boost::num_vertices(g));

for(VI i=vertices(g).first,iend=vertices(g).second;i!=iend;++i){ visited[*i].parent_=*i; };

MyVisitor<VisitedT> vis(visited);

boost::breadth_first_search(g,boost::vertex(0,g),boost::visitor(vis));

-------- code end --------

The compiles OK, but when I run it I got:

Assertion failed: (std::size_t)i < pm.n, file C:/boost_1_46_0/boost/graph/two_bit_color_map.hpp, line 86

which is strange as I do not tweak with the color map. From the trials it seems that the "VisitedT" works if it holds "simple" types like vertex decriptor etc and not aggregates.

That's odd. One thing is that your own visited map is not being used by the breadth-first search, since you did not pass it in as the color map. Is that what you want -- to keep it separately?

My intention with the DataMap to register the vertex parents and the vertex distance at the same time, when the edge is visited. Is there any limit on the library side or did I something wrong?

I don't know yet; there isn't anything in BGL that should prevent what you're doing. Would it be possible to get a stack trace of the assertion failure, and what i and pm.n are where it fails? -- Jeremiah Willcock