Re: [BGL] bad edge iterator range returned by boost::out_edges(v,g)?

From: Chris Russell (cdr_at_[hidden])
Date: 2003-06-03 16:43:05

When in doubt: stare at the code, post a dumb question, take the huskies for
a walk, come back with a theory...

I think this is my own idiocy. Inside the loop I'm making a method call that
removes edges. This invalidates the iterators right?

"Chris Russell" <cdr_at_[hidden]> wrote in message
news:bbj0fu$miu$1_at_main.gmane.org...
> This is weird...
>
> I'm still using BGL from Boost 1_29_0 (which may be an issue?). Anyway,
I've
> got a graph as so:
>
> typedef boost::property<vertex_forest_property_t,
> CProteinCircuitForestVertexProperty,
boost::property<boost::vertex_index_t,
> long, boost::property<boost::vertex_color_t, boost::default_color_type> >
>
> forest_vertex_property_maps_declaration_t;
>
> typedef boost::adjacency_list<boost::listS /*edges*/, boost::listS
> /*vertices*/,  boost::bidirectionalS,
> forest_vertex_property_maps_declaration_t>  forest_graph_t;
>
> I've done a lot with this class, including all kinds of edge traversal.
Now
> suddenly I have a case where boost::out_edges seems to be returning an
> invalid iterator range. I'm absolutely certain the vertex descriptor is
> correct, boost::out_degree returns the expected number of out edges,
however
> I fault inside my access loop because the iterator has gone out of
range....
>
> typedef boost::graph_traits<forest_graph_t>::vertex_descriptor
> forest_vertex_descriptor_t;
> typedef boost::graph_traits<forest_graph_t>::vertex_descriptor
> forest_vertex_descriptor_t;
> typedef boost::graph_traits<forest_graph_t>::edges_size_type
> forest_edges_size_t;
> typedef boost::graph_traits<forest_graph_t>::out_edge_iterator
> forest_edge_out_iterator_t;
>
> forest_edge_out_iterator_t edgeoutiterBegin, edgeoutiterEnd,
> edgeoutiterCurrent;
> boost::tie(edgeoutiterBegin, edgeoutiterEnd) =
> boost::out_edges(v/*forest_vertex_descriptor_t*/,g/*forest_graph_t);
> for (edgeoutiterCurrent = edgeoutiterBegin;
> edgeoutiterCurrent != edgeoutiterEnd ;
> ++edgeoutiterCurrent)
> {
> // works fine through the expected out edges - faults because the loop
fails
> to terminate
> forest_vertex_descriptor_t vertexTarget =
boost::target(*edgeoutiterCurrent,
> g);
> } // end for
>
> Any suggestions would be greatly appreciated. I'm really scratching my
head
> because I've done this exact operation in several other places in the
> algorithm and it works just fine....
>
> TIA - Chris
>
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