Re: [Boost-users] deciding directed and undirected parameter of adjancency list at runtime .

From: abhishek.v_at_[hidden]
Date: 2007-09-12 01:05:06

Hi,,,
In my case i have a input file which holds the graph information . In the 
format
A,B,C,D,E
A,0,1,0,1,0
B,0,0,0,0,1
C,0,1,0,0,1
D,1,0,0,0,1
E,0,0,0,0,0

Now i m able to extract information from the file and create graph using 
adjancency list now what i require is that if the matrix of (0 &1)
is symmetric graph of type undirected should be created and if it is 
unsymmetric it should be BidirectionalS . Will the solution provided
by you to create adaptor help in this senario what could be the best way 
to approach this problem..

Abhishek Vyas
Tata Consultancy Services
Mailto: abhishek.v_at_[hidden]
Website: http://www.tcs.com
____________________________________________
Experience certainty.   IT Services
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boost-users-bounces_at_[hidden] wrote on 09/11/2007 07:09:20 PM:

> abhishek.v_at_[hidden] wrote:
> > I have a function which take an input from the user  whether the graph 

> > is directed or undirected.
> > I'm declaring graph as follows :-
> >
> > typedef adjacency_list < vecS, vecS,* undirectedS*, property < 
> > vertex_name_t,std::string >, property < edge_name_t, std::string > > 
> > Graph;
> > Graph g;
> >
> > Now here the parameter in Bold need to be varied as the user input 
> > changes. One method could be i could have two different function 
> > say,CreateDirected()
> > and CreateUndirected(). But this is not working in my case as i want 
> > the declaration should be global so that i can use it throughout my 
> > application.  Please help.
> That's actually a bit tricky in the BGL, as you've noted. My suggestion 
> would be to use bidirectionalS as the directedness tag, which gives you 
> a directed graph with access to both the incoming and the outgoing 
> edges. Then, it is relatively easy to write a graph adaptor that views 
> an existing bidirectional graph as an undirected graph. I that someone 
> posted on to the Boost mailing list recently, but I can't find it now :(
> 
>     - Doug
> _______________________________________________
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> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users

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