Re: [boost] copying multigraphs

From: Alex Breuer (abreuer_at_[hidden])
Date: 2006-10-06 14:28:03

It would be useful to know exactly where in copy_graph things are  
segfaulting.  It is not unlikely that memory management problems  
upstream of your call to copy_graph are causing things to go bad  
later.  Try using valgrind.

On Oct 5, 2006, at 3:58 PM, Mohamed Anouar Rachdi wrote:

>
>
> Alex Breuer wrote:
>
>> On Oct 5, 2006, at 2:33 PM, Mohamed Anouar Rachdi wrote:
>>
>>
>>
>>> #################################################################### 
>>> ##
>>> ###
>>>  typename graph_traits<Graph>::edge_descriptor    ed;
>>>  bool                                exist;
>>>
>>>  typename graph_traits<Graph>::edge_iterator     ei,  ei_end;
>>>
>>>  Graph copyGraph;
>>>
>>>
>>>  typename boost::property_map<Graph, edge_weight_t>::type weight =
>>> get(edge_weight, graph);
>>>  typename boost::property_map<Graph, edge_index_t>::type edge_id =
>>> get(edge_index, graph);
>>>
>>>
>>>  typename boost::property_map<Graph, edge_weight_t>::type weightc =
>>> get(edge_weight, copyGraph);
>>>  typename boost::property_map<Graph, edge_index_t>::type edge_idc =
>>> get(edge_index, copyGraph);
>>>
>>>
>>>  for ( tie(ei, ei_end)=edges(graph); ei != ei_end; ei++ )
>>>    {
>>>      tie(ed, exist)= add_edge( source(*ei,graph), target(*ei,graph),
>>> copyGraph);
>>>
>>>
>>
>> At this point, you've got a new edge, ed, in your copyGraph, but
>> you're trying to use the edge descriptor from your old graph, ei, to
>> access copyGraph's property maps, which may cause bad things to  
>> happen.
>>
>>
>>
>>>      put(edge_idc, ed, edge_id[*ei]);
>>>      put(weightc, ed, weight[*ei]);
>>>    }
>>>
>>>
>>>
> here i'm just trying to copy the property map from graph to copyGraph
> i think it's the same than doing
> edge_idc[*ed] = edge_id[*ei];
>
> I'm i wrong??
>
> it' doesn't tell me why when i used copy_graph wich is a boost  
> function
> it also behave the same way since i got a segfault at the second  
> call!!!
>
>>> #################################################################### 
>>> ##
>>> ########
>>>
>>>
>>> hello everyone,
>>>
>>> i have a problem with this code that is used inside a fonction  
>>> wich a
>>> call in a loop
>>>
>>> after 2 or 3 calls i have a segfault at the line with add_edge
>>>
>>> i'm using multigraphs
>>>
>>> Ps : i got the same probleme whiel using  copy_graph 
>>> (graph,copyGraph)
>>>
>>>
>>> is there any suggestions.....
>>>
>>> thanx
>>>
>>>
>>>
>>>
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