Re: [Boost-users] Subgraph and internal properties

Hi Hugues, I think that is a bug. I'll look into fixing it. Regards, Jeremy On Feb 3, 2004, at 8:32 AM, Hugues Joly wrote:

Hi, I'm posting again a question that got confused due to mistakes from my part...

I'd like to clarify a point about internal properties accessed through a subgraph. According to the documentation of the method "get(PropertyTag, subgraph& g)":

"vertex and edge properties are shared by all subgraphs, so changes to a property through a local vertex descriptor for one subgraph will change the property for the global vertex descriptor, and therefore for all other subgraphs." (c.f. boost-1.30.2/libs/graph/doc/subgraph.html)

Here, I'm sending you a small program inspired by the boost-1.30.2/libs/graph/example/subgraph.cpp example.

...

From its behavior, it seems that:

1) A property value is not shared between the global descriptor and its corresponding local descriptors.

2) we need to initialize property values for each of the subgraphs. For example, if I set a name "A" for the global vertex descriptor A, that property is not seen through the corresponding local vertex descriptors.

Is this a case of misuse or is it a bug?

__________________________________________________________ Lèche-vitrine ou lèche-écran ? magasinage.yahoo.ca/* Sample output:

After initializing properties for G1: Global and local properties for vertex G0[C]... G0[C]= C G1[A1]= A1 Global and local properties for vertex G0[E]... G0[E]= E G1[B1]= B1 Global and local properties for vertex G0[F]... G0[F]= F G1[C1]= C1

After initializing properties for G2: Global and local properties for vertex G0[A] G0[A]= A G2[A2]= A2 Global and local properties for vertex G0[C]... G0[C]= C G1[A1]= A1 G2[B2]= B2

*/

#include #include <iostream> #include #include #include

int main(int,char*[]) { using namespace boost; //typedef adjacency_list_traits Traits;// Does nothing? typedef property< vertex_color_t, int, property< vertex_name_t, std::string > > VertexProperty;

typedef subgraph< adjacency_list< vecS, vecS, directedS, VertexProperty, property > > Graph;

const int N = 6; Graph G0(N); enum { A, B, C, D, E, F}; // for conveniently refering to vertices in G0

property_map::type name = get(vertex_name_t(), G0); name[A] = "A"; name[B] = "B"; name[C] = "C"; name[D] = "D"; name[E] = "E"; name[F] = "F";

Graph& G1 = G0.create_subgraph(); enum { A1, B1, C1 }; // for conveniently refering to vertices in G1

add_vertex(C, G1); // global vertex C becomes local A1 for G1 add_vertex(E, G1); // global vertex E becomes local B1 for G1 add_vertex(F, G1); // global vertex F becomes local C1 for G1

property_map::type name1 = get(vertex_name_t(), G1); name1[A1] = "A1";

std::cout << std::endl << "After initializing properties for G1:" << std::endl; std::cout << " Global and local properties for vertex G0[C]..." << std::endl; std::cout << " G0[C]= " << boost::get(vertex_name, G0, C) << std::endl;// prints: "G0[C]= C" std::cout << " G1[A1]= " << boost::get(vertex_name, G1, A1) << std::endl;// prints: "G1[A1]= A1"

name1[B1] = "B1";

std::cout << " Global and local properties for vertex G0[E]..." << std::endl; std::cout << " G0[E]= " << boost::get(vertex_name, G0, E) << std::endl;// prints: "G0[E]= E" std::cout << " G1[B1]= " << boost::get(vertex_name, G1, B1) << std::endl;// prints: "G1[B1]= B1"

name1[C1] = "C1";

std::cout << " Global and local properties for vertex G0[F]..." << std::endl; std::cout << " G0[F]= " << boost::get(vertex_name, G0, F) << std::endl;// prints: "G0[F]= F" std::cout << " G1[C1]= " << boost::get(vertex_name, G1, C1) << std::endl;// prints: "G1[C1]= C1"

Graph& G2 = G0.create_subgraph(); enum { A2, B2 }; // for conveniently refering to vertices in G2

add_vertex(A, G2); // global vertex A becomes local A2 for G2 add_vertex(C, G2); // global vertex C becomes local B2 for G2

property_map::type name2 = get(vertex_name_t(), G2); name2[A2] = "A2";

std::cout << std::endl << std::endl << "After initializing properties for G2:" << std::endl; std::cout << " Global and local properties for vertex G0[A]" << std::endl; std::cout << " G0[A]= " << boost::get(vertex_name, G0, A) << std::endl;// prints: "G0[A]= A" std::cout << " G2[A2]= " << boost::get(vertex_name, G2, A2) << std::endl;// prints: "G2[A2]= A2"

name2[B2] = "B2";

std::cout << " Global and local properties for vertex G0[C]..." << std::endl; std::cout << " G0[C]= " << boost::get(vertex_name, G0, C) << std::endl;// prints: "G0[C]= C" std::cout << " G1[A1]= " << boost::get(vertex_name, G1, A1) << std::endl;// prints: "G1[A1]= A1" std::cout << " G2[B2]= " << boost::get(vertex_name, G2, B2) << std::endl;// prints: "G2[B2]= B2"

return 0; } _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

_______________________________________________ Jeremy Siek http://www.osl.iu.edu.edu/~jsiek Ph.D. Student, Indiana University Bloomington C++ Booster (http://www.boost.org) Office phone: (812) 856-1820 _______________________________________________