Re: [Boost-users] [BGL] creating a single vertex for the loop in a graph

Subject: Re: [Boost-users] [BGL] creating a single vertex for the loop in a graph
From: Jeremiah Willcock (jewillco_at_[hidden])
Date: 2012-01-12 14:01:08

On Thu, 12 Jan 2012, srinivas boppu wrote:

> Hello All,
> 
> I am looking for the following in boost graph.
> 
> I have a graph in which I am able to find out the loops.
> Now, I wanted to  replace the  whole loop with  a  single vertex in the same Graph.
> 
> Is that possible ? if it is, can you suggest me how do it.

Is this a directed graph?  Are you trying to replace each strongly 
connected component with a single vertex?  In that case, look at 
boost/graph/create_condensation_graph.hpp (undocumented AFAIK) and see if 
it does what you want.  If you just need a topological sort of the 
components, use the normal strong_components() function.

> Alternate way could be, I copy the loop and make another graph and  add this  whole graph
> as  a "vertex" in initial  graph.
> 
> Can I add a  "graph" as  a vertex to existing graph?   

No; you could have a graph with a vertex property that is another graph, 
but that will not allow the graphs stored in properties to link to each 
other.

-- Jeremiah Willcock