BGL gurus:
I would like to use listS for vertex and edge lists because of
iterator stability.
However, if I run the following code:
------------
// use listS
typedef adjacency_list Pgraph;
// use vecS
typedef adjacency_list Pgraph2;
int num_vertices = 2;
Pgraph pg (num_vertices);
boost::graph_traits<Pgraph>::vertex_iterator vi, vi_end;
boost::tie(vi, vi_end) = vertices(pg);
Pgraph2 pg2 (num_vertices);
boost::graph_traits<Pgraph2>::vertex_iterator vi2, vi_end2;
boost::tie(vi2, vi_end2) = vertices(pg2);
for (vi, vi2; vi != vi_end && vi2 != vi_end2; vi++, vi2++)
{
std::cout << *vi << std::endl;
std::cout << *vi2 << std::endl;
}
------------
I get the following output:
------------
0x00146e60 <- this is *vi which uses listS
0 <- this is *vi2 which uses vecS
0x00146e78 <- this is *vi which uses listS
1 <- this is *vi2 which uses vecS
------------
One of the problems with this is when I try to display the graph
using write_graphviz. Vertex indices turn out be 0x0014e60 etc
instead of nice numbers like 0, 1, etc.
Tracing execution through the debugger, it appears that vi and
vi_end are of type generic_iterator(), whereas vi2 and vi2_end are
of type iterator_adaptor() defined in boost/iterator_adaptors.hpp .
Unfortunately, this is where my c++ expertise peters out.
So what is happenning here? And is there anything I can do to ensure
iterator stability while using vecS?
Any help will be much appreciated,
S
