Re: [Boost-users] [graph] Is reverse_graph<> read-only?

Subject: Re: [Boost-users] [graph] Is reverse_graph<> read-only?
From: Cedric Laczny (cedric.laczny_at_[hidden])
Date: 2011-02-18 01:41:51

Hi Jeremiah,

On Friday, 18. February 2011 00:14:08 Jeremiah Willcock wrote:
> On Fri, 18 Feb 2011, al.zatv wrote:
> > Jeremiah Willcock <jewillco_at_[hidden]> писал(а) в своём письме Fri, 18
> > Feb
> > 
> > 2011 01:49:27 +0300:
> >>> Is reverse_graph<> in Boost::Graph Library, read-only?
> >> 
> >> It appears to be read-only.  It should be possible to add mutation; it
> >> just isn't there yet.  Do you need that feature?
> > 
> > Yes. My program build two trees in the same graph. First tree is
> > "forward". Second tree is "backward": build by the same algorithm, but
> > in reverse order. So I need add_vertex and add_edge for reverse trees. I
> > wrote them this way (please look if I'm correct - because I'm a newbie
> > and can make stupid errors).
> 
> Do those versions work?  I forgot whether edge_descriptors in the original
> graph are implicitly convertible to edge_descriptors in the reverse_graph;
> your implementations require that. 

Just of pure interest, where do you see this requirement in the code? It's not 
that I doubt the fact that it actually is like this but I am interested in 
knowing how this can be seen in these short, two functions?

> Your code would be easy to fix for the
> other case, though. 

Again, I would really like to know how.

> Could you please add in the rest of the mutating
> functions so that I can add your code to BGL?
> 
> -- Jeremiah Willcock

Thank you.

Best,

Cedric