Re: [Boost-users] Function pointer to in/out_degree in BGL

Subject: Re: [Boost-users] Function pointer to in/out_degree in BGL
From: Jeremiah Willcock (jewillco_at_[hidden])
Date: 2010-10-26 16:27:11

On Tue, 26 Oct 2010, langermatze wrote:

>
> Hi,
>
> I have a question regarding the boost graph library. I'd like to write a set
> of depth first search visitors to determine the maximum in/out-degree of a
> graph. The code should look pretty similar for both cases except for the
> function call to get the property of the visited node.
> boost:in_degree(node_id, graph) vs. boost:out_degree(vertexId, graph)
>
> At first glance the function signature pretty much the same, maybe:
>
> template<class Graph>
> graph_traits<Graph>::degree_size_type
> function(graph_traits<Graph>::vertex_descriptor u, const Graph &g)
>
> When looking at the BGL headers however, things seem to be a bit more
> complex, though.
> I tried to implement a generic dfs_visitor taking a general function pointer
> to get the in/out degree property of the visited node but I couldn't work
> out the type of the function pointer to be passed. All my attemtps failed
> badly. Hopefully, there is anybody on this list who has a better
> understanding of this business and could provide some help. Any
> hints/comments are appreciated!

Although using a function pointer would not perform well, you could 
probably make it work.  What errors are you getting?  Most likely, you 
might need an explicit cast from &in_degree to the correct function 
pointer type for your graph; otherwise, you might get an error like 
"improper use of overloaded function" or such.

-- Jeremiah Willcock