Re: [Boost-users] [BGL] topological_sort compile error

From: Aaron Windsor (aaron.windsor_at_[hidden])
Date: 2007-06-04 22:06:13

On 6/4/07, David A. Greene <greened_at_[hidden]> wrote:
> Hi everyone,
>
> I'm having trouble with BGL's (Boost 1.33.1) topological sort.  In my
> source code I have this simple call:
>
>          std::vector<my_vertex> rev_topo_order;
>          topological_sort(*t, std::back_inserter(rev_topo_order));
>
> Here "t" is an iterator to a list of graphs declared like this:
>
>       typedef boost::adjacency_list<
>         boost::setS,               // Out edge list type
>         boost::listS,              // Vertex list type
>         boost::bidirectionalS,     // Needed for DAG, topo sort
>         my_property_bundle // Vertex properties
>         > my_graph_type;
>

<snip>

Hi Dave,

The error you're seeing (both in your code and the example you
included) is caused because the topological sort algorithm expects a
vertex index map - if you don't provide one as a parameter, it uses
whatever interior vertex index map the graph has. Even if you declare
a vertex index map as an interior property of the graph, you still
have to initialize it by mapping each vertex to an integer in the
range 0..num_vertices(g)-1. See #5 in the BGL FAQ
(http://www.boost.org/libs/graph/doc/faq.html) for an example of how
to initialize one.

Regards,
Aaron