Dear list,
the documentation of adjacency_list states, that a call to add_vertex()
does not invalidate any iterators nor descriptors. However, following
code segfaults, because retrieving vertex descriptors from an
edge_iterator via source() and target() does not work (example should
compile as is):
#include <iostream>
#include
using namespace boost;
typedef adjacency_list Graph;
int main() {
Graph g(3);
add_edge( 0, 1, g );
add_edge( 1, 2, g );
add_edge( 2, 0, g );
Graph::edge_iterator ei, ei_end;
for( tie( ei, ei_end ) = edges( g ); ei != ei_end; ++ei )
{
std::cout << source( *ei, g ) << " " << target( *ei, g ) << "\n";
add_vertex( g ); // <- in my real application, vertex gets some
// properties that depend on source(...) and
// target(...) above
}
}
Is it the case that an edge_iterator does not store vertex_descriptors
(that should survive reallocation of the vertex storage), but iterators
to the vertex storage?
What is the proper way to accomplish something like this? My present
workaround is to postpone all add_vertex() calls after the loop, but
this costs some storage, and with my graph scaling bigger and bigger,
that begins to hurt.
Any help and explanation is really appreciated!
Regards,
Julius
