[graph] problem with weight_map ? (brandes_betweenness_centrality)
Hi all, I think I've got a problem with the way I use the weight property map in my betweenness_centrality (and maybe other locations too). I've got a graph like that: typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph; And I add edges with weights like that (simplified): EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f std::pair<unGraph::edge_descriptor, bool> e = boost::add_edge(a, b, weight, m_ugraph); Than I try to do the brandes_centrality_betweenness: std::vector< double > v_centrality_vec(boost::num_vertices(m_ugraph), 0.0); boost::brandes_betweenness_centrality(m_ugraph , boost::centrality_map(boost::make_iterator_property_map(v_centrality_vec.begin(),boost::get(boost::vertex_index, m_ugraph),double())).vertex_index_map(get(boost::vertex_index, m_ugraph)).weight_map(get(boost::edge_weight, m_ugraph)) ); But I get crazy results... 1) I have checked by hand that my "getWeight" (my weights) are OK. 2) I have set _ALL_ weights to 1.0 (almost as if brandes was using BFS internally), Again I get the _SAME_ crazy results! So there is something wrong with the way Im using the weight_map. What am I missing?? Best, Tasos
My newline character got crazy.. Sorry. I separate some line below for easier reading. typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty;
### typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph;
###
EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f
###
std::pair<unGraph::edge_descriptor, bool> e = boost::add_edge(a, b, weight, m_ugraph);
###
std::vector< double > v_centrality_vec(boost::num_vertices(m_ugraph), 0.0); ###
boost::brandes_betweenness_centrality(m_ugraph , boost::centrality_map(boost::make_iterator_property_map(v_centrality_vec.begin(),boost::get(boost::vertex_index, m_ugraph),double())).vertex_index_map(get(boost::vertex_index, m_ugraph)).weight_map(get(boost::edge_weight, m_ugraph)) );
On Tue, Mar 19, 2013 at 12:52 PM, The Maschine < justthemaschine@googlemail.com> wrote:
Hi all,
I think I've got a problem with the way I use the weight property map in my betweenness_centrality (and maybe other locations too).
I've got a graph like that:
typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty;
typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph;
And I add edges with weights like that (simplified):
EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f
std::pair<unGraph::edge_descriptor, bool> e = boost::add_edge(a, b, weight, m_ugraph);
Than I try to do the brandes_centrality_betweenness:
std::vector< double > v_centrality_vec(boost::num_vertices(m_ugraph), 0.0);
boost::brandes_betweenness_centrality(m_ugraph , boost::centrality_map(boost::make_iterator_property_map(v_centrality_vec.begin(),boost::get(boost::vertex_index, m_ugraph),double())).vertex_index_map(get(boost::vertex_index, m_ugraph)).weight_map(get(boost::edge_weight, m_ugraph)) );
But I get crazy results...
1) I have checked by hand that my "getWeight" (my weights) are OK.
2) I have set _ALL_ weights to 1.0 (almost as if brandes was using BFS internally), Again I get the _SAME_ crazy results!
So there is something wrong with the way Im using the weight_map.
What am I missing??
Best,
Tasos
On Tue, 19 Mar 2013, The Maschine wrote:
Hi all, I think I've got a problem with the way I use the weight property map in my betweenness_centrality (and maybe other locations too).
I've got a graph like that:
typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty;
typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph;
And I add edges with weights like that (simplified):
EdgeWeightProperty weight = getWeight(a, b); // 0f ... 2.0f
Can you just assign a double to a boost::property<...> object? That should probably not be allowed.
std::pair<unGraph::edge_descriptor, bool> e = boost::add_edge(a, b, weight, m_ugraph);
Than I try to do the brandes_centrality_betweenness: std::vector< double > v_centrality_vec(boost::num_vertices(m_ugraph), 0.0);
boost::brandes_betweenness_centrality(m_ugraph , boost::centrality_map(boost::make_iterator_property_map(v_centrality_vec.begin(),boost::get(boost::vertex_index, m_ug raph),double())).vertex_index_map(get(boost::vertex_index, m_ugraph)).weight_map(get(boost::edge_weight, m_ugraph)) );
But I get crazy results... 1) I have checked by hand that my "getWeight" (my weights) are OK. 2) I have set _ALL_ weights to 1.0 (almost as if brandes was using BFS internally), Again I get the _SAME_ crazy results!
What happens if you write an explicit loop over all of the edges and use put(edge_weight, g, e) directly? Does that change any of the results? -- Jeremiah Willcock
participants (2)
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Jeremiah Willcock -
The Maschine