Re: [Boost-users] [BGL]Why the output of algorithms are vertex sequence(PredecessorMap)? How about parallel edges??

Subject: Re: [Boost-users] [BGL]Why the output of algorithms are vertex sequence(PredecessorMap)? How about parallel edges??
From: Li Ning (Ning.c.Li_at_[hidden])
Date: 2009-05-11 01:41:06

Andrew Sutton-2 wrote:
> 
>>
>>    "Remove" also invalidates vertex descriptors!
>>>
>>>
>>> For VertexList == vecS, yes. My advice regarding this would be: If
>>> you're
>>> using vecS for vectors, don't remove vertices. If you have to remove
>>> vertices, use listS and never call num_vertices,
>>>
>>> For anything other than vecS, remove_vertex shouldn't invalidate
>>> descriptors other than the one removed. I hope.
>>>
>>
>> Yes, and as I understand it, ditto iterators.
>> So the question still stands!
> 
> 
> I can rephrase my previous answer. Descriptors provide improved stability
> over iterators. With vectors, iterators are invalidated on insert and
> erase,
> but descriptors are only invalidated on erase/remove. With linked memory
> structures (e.g,. lists and trees) neither set of operations (should)
> invalidate other iterators or descriptors.
> 
> Andrew Sutton
> andrew.n.sutton_at_[hidden]
> 
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
> 

I understand. The descriptor exists because of 'add_edge' like functions.
And the inter-reference between vertex & edge is operated on descriptor will
eliminate affect of 'add' operation. However, remove still has invalidate
problem.
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