Re: [Boost-users] Usage of Transitive_closure().

From: nruan (nruan_at_[hidden])
Date: 2007-10-08 10:44:57

Thank you very much. I forget to initialize the indexmap, it works now.
Ning

Aaron Windsor wrote:
> On 10/7/07, Ning Ruan <nruan_at_[hidden]> wrote:
>   
>> my code to use transitive_closure():
>>         Graph tc;
>>         VertexIndexMap index_map = get(&VertexProp::id, g);
>>         vector<Vertex> to_tc_vec(num_vertices(g));
>>         iterator_property_map<Vertex*, VertexIndexMap, Vertex, Vertex&>
>>                 g_to_tc_map(&to_tc_vec[0], index_map);
>>         transitive_closure(graph, tc, g_to_tc_map, (index_map));
>>
>> I use print_graph(tc, get(&VertexProp::id, tc) to print the transitive
>> graph, then it shows:
>> 0 --> 0 0 0 0 0 0 0 0
>> 0 --> 0 0
>> 0 -->
>> 0 --> 0 0 0 0 0 0 0 0
>> 0 -->
>> 0 -->
>> 0 --> 0 0 0
>> 0 --> 0 0 0 0 0 0 0 0
>>
>> the result miss the id of vertex, what 's the problem. my original graph
>> g is correcet:
>>
>> 0 --> 1 2 3
>> 1 --> 4 5
>> 2 -->
>> 3 --> 6 7
>> 4 -->
>> 5 -->
>> 6 --> 1
>> 7 --> 0
>>     
>
> Hi Ning,
>
> Do you ever initialize the VertexProp::id property? For example:
>
> VertexIndexMap index_map = get(&VertexProp::id, g);
> graph_traits<Graph>::vertices_size_type count = 0;
> graph_traits<Graph>::vertex_iterator vi, vi_end;
> for(tie(vi, vi_end) = vertices(tc); vi != vi_end; ++vi)
>     index_map[*vi] = count++;
>
> If you aren't initializing it, that's the problem. If you are
> initializing it, please show a little more of your code - in
> particular the typedef you're using for Graph.
>
> Regards,
> Aaron
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