CGAL users discussion list

[Andreas Fabri <>]

Hi Jasmine,

A bug in the example, not in CGAL or the BGL.


When calling
boost::kruskal_minimum_spanning_tree(ft,
                                        std::back_inserter(mst),
                                        vertex_index_map(vertex_index_pmap));


the first argument must be ft, that is the filtered
graph where the infinite vertex is ignored (In the
example it was t instead of ft).

I fixed it in the code base for the next release.

Best,

Andreas


On 23/10/2014 07:23, jasmine2210 wrote:
> Hello,
>
> I'm trying to run CGAL with Boost Graph Library - Kruskal Minimum Spanning
> Tree with my input. The code is exactly in this url:
> https://doc.cgal.org/4.2/CGAL.CGAL.CGAL-and-the-Boost-Graph-Library/html/BGL_triangulation_2_2emst_8cpp-example.html
>
> My input is
>
> 0. 0.
> 1. 1.
> 0. 2.
> 1. 0.
>
> But when I run it, the output is not nice. This is the output of edges in
> minimum spanning tree (EMST). Each line is an edge which is a pair of
> points.
>
> (0 6.95331e-310) - (0 0)
> (1 1) - (1 0)
> (1 1) - (0 2)
>
> However, when I print the Delaunay Triangulation, the output is as expected.
>
> (0 0) - (0 2)
> (0 0) - (1 1)
> (1 1) - (0 2)
> (1 1) - (1 0)
> (0 0) - (1 0)
>
> I think it should be (0,0) in the first line in output of EMST. Moreover, I
> don't think it's correct that the edge (0 0) - (0 0) is in the EMST. Could
> you please let me know where is the root cause of my issue.
>
>
>
> --
> View this message in context: 
> http://cgal-discuss.949826.n4.nabble.com/Boost-Kruskal-Minimum-Spanning-Tree-tp4659990.html
> Sent from the cgal-discuss mailing list archive at Nabble.com.

--
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: +33.492.954.912    skype: andreas.fabri