Hi,
I was trying to use an iterator_property_map with bundled properties and ran
into difficulties. For those having thought about that, I want to post my
solution and also address a question.
Let's start with the solution:
Imagine, one uses bundled properties and has defined the following
EdgeProperty:
struct EdgeProperty{
int edge_index;
}
and
typedef adjacency_list<...> Graph;
Whether this makes sense or not may also be discussed but is not important for
the demonstration purposes.
So if you now want to define an iterator_property_map that is based on the
edge_index, it get's IMHO a bit more complicated than using internal
properties:
typedef property_map::type EdgeIndexMap;
EdgeIndexMap e_index = get(&EdgeProperty::edge_index,g);
std::vector< int > flag_vec(num_edges(g), 0);
// Create the external property map
iterator_property_map< std::vector< int >::iterator, EdgeIndexMap >
flags(flag_vec.begin(), e_index);
versus an example using vertex_index that is automatically created when using
vecS for the vertices:
typedef property_map::type VertexIndexMap;
VertexIndexMap v_index = get(vertex_index, g);
std::vector< int > flag_vec(num_vertices(g), 0);
// Create the external property map
iterator_property_map< std::vector< int >::iterator, VertexIndexMap >
flags(flag_vec.begin(), v_index);
So far for the solution.
I have also a question in this place:
What does the "EdgeProperty::*" exactly do? The EdgeProperty is of course the
bundle, but what about the "::*" is this some sort of RegEx for "all
attributes of this bundle"?
I looked at the code in properties.hpp and was able to generally understand
the idea, but it did not become clear to me why the "::*" is needed.
Thank you.
Best,
Cedric
