Hi all,
I have a basic question about BGL, but I'm a bit too new with templating
to understand some of the terms used in the documentation... :-(
I'd like to build a graph using an adjacency matrix and the
edge_iterator_constructor of the graph (or anything faster than repeated
add_edge's). In the docs, I found this for adjacency_list:
template <class EdgeIterator>
adjacency_list(EdgeIterator first, EdgeIterator last,
vertices_size_type n,
edges_size_type m = 0,
const GraphProperty& p = GraphProperty())
but the closest I found for adjacency_matrix is:
template <typename EdgeIterator>
adjacency_matrix(EdgeIterator first,
EdgeIterator last,
vertices_size_type n,
const GraphProperty& p = GraphProperty())
It's not the same because of "typename"? As a toy example, I've taken
the MST example and have modified it a lot to get this:
-----
#include
#include
#include
#include <iostream>
int main () {
using namespace boost;
typedef adjacency_matrix < undirectedS, no_property, property <
edge_weight_t, int > > Graph;
typedef graph_traits < Graph >::edge_descriptor Edge;
typedef graph_traits < Graph >::vertex_descriptor Vertex;
typedef std::pair E;
const int num_nodes = 5;
E edges[] = { E(0, 2), E(1, 3), E(1, 4), E(2, 1), E(2, 3),
E(3, 4), E(4, 0)
};
int weights[] = { 1, 1, 2, 7, 3, 1, 1 };
std::size_t num_edges = sizeof(edges) / sizeof(E);
Graph g1 (num_nodes);
for (unsigned int i = 0; i < num_edges; i++) {
add_edge (edges[i].first, edges[i].second, g1);
}
print_graph (g1);
Graph g2 (num_nodes);
// Graph g2 (edges, edges + num_edges, weights, num_nodes);
print_graph (g2);
return EXIT_SUCCESS;
}
-----
The 5th line from the end is what is causing me problems. It seemed to
work with an adjacency_list. (I'd also would like to add weights, but I
guess add_edge could support that...I just think that this way is faster
based on the "Quick Tour of the BGL" page in the docs.)
I looked in my examples directory [1.39] and simply grepped for
"adjacency_matrix" and came up with only one file: adjacency_matrix.cpp
. Other than the pros/cons of adjacency matrices and lists, is there
something wrong with adjacency matrices; any reason for its absence in
the examples directory?
One final question -- in the documentation, it lists various graph
concepts
(http://www.boost.org/doc/libs/1_40_0/libs/graph/doc/graph_concepts.html)
such as BidirectionalGraph, VertexAndEdgeListGraph, AdjacencyMatrix,
etc. Are these concepts relevant to BGL or only in a general sense?
What I mean is what is their relationship with adjacency_list and
adjacency_matrix? Any pointers would be appreciated...
Thank you!
Ray
