Re: [Boost-users] 1.33.1 read_graphviz possible parser issue

From: Brian Stadler (bdotstadler_at_[hidden])
Date: 2007-09-19 10:41:04

Ron,

Code for writing is very simple.  I dont use this code unless I am doing
testing.

ofstream fo(filename.c_str());
write_graphviz(fo, [graph here]);
fo.close();

The function you speak of is listed on
http://boost.org/libs/graph/doc/write-graphviz.html.  It is included with
1.33.1.

To be honest, I wish read_graphviz() did not require a dynamic properties
object.  If one wants to read a very simple dot file without any extra stuff
then they basically have to create a fake dp object just to do this.

Quick note,  I changed the dot files I was reading in from the original post
to the following, which is the way the boost library outputs them.

graph G {
"0";
"1";
"2";
"0" -- "1";
"0" -- "2";
"1" -- "2";
}

Vertices are quoted but boost is able to handle it correctly.

--Brian

On 9/18/07, Ronald Garcia <garcia_at_[hidden]> wrote:
>
> Hi Brian,
> I can see from your code snippet how your are reading the graph in.  Could
> you show the code for how  you are writing the graph out?
> I'm not sure if the interface has changed since 1.33.1, but with the
> version in CVS, you can pass along the dynamic_properties object and the
> name of the property to use for vertex names in order to get the same graph
> out:
>
> // Graph structure with dynamic property output
> template<typename Graph>
> void
> write_graphviz(std::ostream& out, const Graph& g,
>                const dynamic_properties& dp,
>                const std::string& node_id = "node_id");
>
>
>
> HTH,
> ron
>
> On Sep 17, 2007, at 1:45 PM, Brian Stadler wrote:
>
> Good observation.  I see exactly what it's doing now.
>
> However, this is still a bug.  If one is using dot language files across
> different programs then the parser needs to interpret it the same.  Though
> the graph may retain its overall structure, the structure for that
> individual vertex has now changed.  This will adversely affect the way
> algorithms make entree into the graph.  For example, if vertex 0 once had a
> degree of two and now has a degree of 3 than the choices to move from 0 have
> changed from two choices to three.
>
> thanks again for the response!
>
> On 9/17/07, Krishna Roskin <krish_at_[hidden]> wrote:
> >
> > On 9/14/07, Brian Stadler <bdotstadler_at_[hidden]> wrote:
> > > My read_graphviz code:
> > >
> > > bool file;
> > > ifstream in(openfile.c_str(), ios::in);
> > > dynamic_properties dp;
> > > dp.property ("node_id", get(&ed_node::vertex_name, ug));  <--simple
> > > adjacency list with bundled properties being used
> > > file = read_graphviz(in, ug, dp, "node_id");
> > >
> > > Source graphviz file:
> > >
> > > strict graph  {
> > >     0 -- 3;
> > >     0 -- 4;
> > >     1 -- 3;
> > >     1 -- 4;
> > >     2 -- 3;
> > >     2 -- 4;
> > >     3 -- 4;
> > > }
> > >
> > > Output graphviz file:
> > >
> > > graph G {
> > > 0;
> > > 1;
> > > 2;
> > > 3;
> > > 4;
> > > 0--1 ;
> > > 0--2 ;
> > > 3--1 ;
> > > 3--2 ;
> > > 4--1 ;
> > > 4--2 ;
> > > 1--2 ;
> > > }
> >
> >
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>