Re: [Boost-users] How to find edge between two vertices of undirected graph?

Subject: Re: [Boost-users] How to find edge between two vertices of undirected graph?
From: Eric Fowler (eric.fowler_at_[hidden])
Date: 2010-06-13 23:05:13

On Fri, Jun 11, 2010 at 12:29 PM, Jeremiah Willcock <jewillco_at_[hidden]>wrote:

> On Thu, 10 Jun 2010, Eric Fowler wrote:
>
>  It seems I do not have a mutable graph. This sort of raises another issue:
>> how do I declare an object that is described by a concept?
>>
>
> The best you can do is apply a concept checking class.  That doesn't filter
> the members so you can only use the MutableGraph-required functions, but it
> at least makes sure that the graph you have is a MutableGraph.
>
>
>  For example, in this case I know I need a MutableGraph, and I see from the
>> doc (
>> http://www.boost.org/doc/libs/1_43_0/libs/graph/doc/MutableGraph.html)
>> that MutableGraphs
>> have certain properties, such as DefaultConstructible, etc.
>>
>> Now, how do I declare a MutableGraph, and know I have one? I know that:
>>
>>  typedef adjacency_list<vecS, vecS, undirectedS,
>> POS<position_type> LEN<position_type> > DG;
>>
>
> What methods are missing?  Could you please try applying the MutableGraph
> concept checking class to the DG type and see what breaks?

Again I must ask: How? I have mined the examples and come up with:
BOOST_CONCEPT_ASSERT((MutableGraph<DG>));
and
BOOST_CONCEPT_ASSERT((MutableGraph<DG<int>));
BOOST_CONCEPT_ASSERT((BidirectionalGraph<DG<int>));

and put them the head of a .cpp file that uses DG. These have generated
obscure and unhelpful error messages.

Copying this line from the examples and using it in the same place produces
no errors:

BOOST_CONCEPT_ASSERT((BidirectionalIterator<std::list<int>::iterator>));

>>
> What do you mean?  You want to add methods/functions to the graph type to
> make it model a specific concept?
>

No. I mean, yes. I want to know how to define my graph type so it models a
specific concept.

Eric

>
> -- Jeremiah Willcock
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