Re: [Boost-users] [graph] Bug - add_edge (adjacency_list) does not report if edge already exists as stated in documentation

From: Martin Mann (mmann_at_[hidden])
Date: 2008-08-07 06:23:03

Hi Dmitry,

thanks for your reply. Yes this might fix the problem. But than the 
documentation of "add_edge" is missleading because it should hold for 
vecS too.

Unfortunately I have to stick to vecS due to some other reasons like 
automatic vertex indexing via properties etc. So I used the workaround 
with first checking for the presence of the edge via "edge(..).second".

Thanks,
Martin

Dmitry Bufistov wrote:
> Hi Martin,
> I think everything is more or less correct here. Changing your graph 
> representation to
> boost::adjacency_list<boost::setS, boost::vecS, boost::undirectedS>
> results in the behavior you expect.
> 
> Regards,
> Dmitry
> 
> Martin Mann wrote:
>>
>> Hi,
>>
>> I encountered the following problem :
>>
>> a successive call with equal parameters u, v, and g of
>>
>> ============================================================
>> std::pair<edge_descriptor, bool>
>>    add_edge(   vertex_descriptor u
>>              , vertex_descriptor v
>>              , adjacency_list&   g )
>> ============================================================
>>
>> yields both times "RESULT.second == true".
>>
>> But the documentation states, that only in case it is NOT PRESENT it 
>> should be true, which is obviously wrong for the second call.
>>
> 
>>       //! The definition of a the internal graph representation
>> typedef boost::adjacency_list< boost::vecS
>>                                , boost::vecS
>>                                , boost::undirectedS
>>                                , CoreGraph_NodeProperties
>>                                , CoreGraph_EdgeProperties
>>             >  CoreGraph;
>>
>> ============================================================
> 
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