Re: [boost] [BGL] Multithread problem inserting edges and exploring the same graph

Subject: Re: [boost] [BGL] Multithread problem inserting edges and exploring the same graph
From: Christoph Heindl (christoph.heindl_at_[hidden])
Date: 2009-09-19 02:23:18

Cosimo,

you might also consider using a snapshot of the graph (i.e copy) in
each explorer thread. This might well outperform a mutexed solution
when the number of concurrent accesses to edges is high. The only
thing to be synchronized then is generating a copy of the graph.

Best regards,
Christoph

On Fri, Sep 18, 2009 at 2:47 PM, Cosimo Calabrese
<cosimo.calabrese_at_[hidden]> wrote:
>
>> Now I'm trying to implement the EdgeMutableGraph concept, in order to
>> obtain the add_edge() support, but I've a problem.
>>
>> template <typename G>
>> std::pair<typename sync_adjacency_list<G>::edge_descriptor, bool>
>> add_edge(const typename sync_adjacency_list<G>::vertex_descriptor u,
>>         const typename sync_adjacency_list<G>::vertex_descriptor v,
>>         const sync_adjacency_list<G>& g)
>> {
>>  interprocess::scoped_lock<interprocess::interprocess_mutex>
>>  lock( sync_adjacency_list_mutex );
>>  return add_edge(u, v, g.m_g);
>> }
>>
>> When I try to use it with G = adjacency_list< listS, vecS, directedS,
>> vertexs_properties, edges_properties >, I'm obtaining the follow compile
>> error message:
>>
>> "error C2665: 'boost::add_edge' : none of the 2 overloads could convert
>> all the argument types"
>>
>> It seems that the compiler can't find the right implementation of
>> add_edge(). It's strange, because I'm sure that the add_edge() exists for
>> adjacency_list<...>. The add_edge() version I've implementated is only a
>> wrapper of it.
>>
>> Where I'm wrong? Is it a MSVC 2005 function resolution bug?
>>
>
>
> I've found the add_edge() problem: I've defined 'const' the internal graph
> reference of sync_adjacency_list... without const, it works. This is the
> adaptor (the 'const' is now commented):
>
>
> template <typename Graph>
> class sync_adjacency_list {
>  typedef graph_traits<Graph> Traits;
>  typedef sync_adjacency_list<Graph> self;
> public:
>  typedef Graph graph_type;
>  sync_adjacency_list( /*const*/ Graph& g) : m_g(g) { }
>
>  // .....
>
>  /*const*/ Graph& m_g;
> }
>
>
> Now, I'll test it...
>
> Cosimo Calabrese.
>
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