typename property_traits<CoreMap>::value_type
core_numbers_impl(Graph& g, CoreMap c, EdgeWeightMap wm,
MutableQueue& Q, Visitor vis)
{
typename property_traits<CoreMap>::value_type v_cn = 0;
typedef typename graph_traits<Graph>::vertex_descriptor vertex;
while (!Q.empty())
{
// remove v from the Q, and then decrease the core numbers
// of its successors
vertex v = Q.top();
vis.examine_vertex(v,g);
Q.pop();
v_cn = get(c,v);
typename graph_traits<Graph>::out_edge_iterator oi,oi_end;
for (boost::tie(oi,oi_end) = out_edges(v,g); oi!=oi_end; ++oi) {
vis.examine_edge(*oi,g);
vertex u = target(*oi,g);
// if c[u] > c[v], then u is still in the graph,
if (get(c,u) > v_cn) {
// remove the edge
put(c,u,get(c,u)-get(wm,*oi));
if (Q.contains(u))
Q.update(u);
}
}
vis.finish_vertex(v,g);
}
return (v_cn);
}
typename property_traits<CoreMap>::value_type
core_numbers_impl(Graph& g, CoreMap c, PositionMap pos, Visitor vis)
{
typedef typename graph_traits<Graph>::vertices_size_type size_type;
typedef typename graph_traits<Graph>::degree_size_type degree_type;
typedef typename graph_traits<Graph>::vertex_descriptor vertex;
typename graph_traits<Graph>::vertex_iterator vi,vi_end;
// store the vertex core numbers
typename property_traits<CoreMap>::value_type v_cn = 0;
// compute the maximum degree (degrees are in the coremap)
typename graph_traits<Graph>::degree_size_type max_deg = 0;
for (boost::tie(vi,vi_end) = vertices(g); vi!=vi_end; ++vi) {
max_deg = (std::max<typename graph_traits<Graph>::degree_size_type>)(max_deg, get(c,*vi));
}
// store the vertices in bins by their degree
// allocate two extra locations to ease boundary cases
std::vector<size_type> bin(max_deg+2);
for (boost::tie(vi,vi_end) = vertices(g); vi!=vi_end; ++vi) {
++bin[get(c,*vi)];
}
// this loop sets bin[d] to the starting position of vertices
// with degree d in the vert array for the bucket sort
size_type cur_pos = 0;
for (degree_type cur_deg = 0; cur_deg < max_deg+2; ++cur_deg) {
degree_type tmp = bin[cur_deg];
bin[cur_deg] = cur_pos;
cur_pos += tmp;
}
// perform the bucket sort with pos and vert so that
// pos[0] is the vertex of smallest degree
std::vector<vertex> vert(num_vertices(g));
for (boost::tie(vi,vi_end) = vertices(g); vi!=vi_end; ++vi) {
vertex v=*vi;
size_type p=bin[get(c,v)];
put(pos,v,p);
vert[p]=v;
++bin[get(c,v)];
}
// we ``abused'' bin while placing the vertices, now,
// we need to restore it
std::copy(boost::make_reverse_iterator(bin.end()-2),
boost::make_reverse_iterator(bin.begin()),
boost::make_reverse_iterator(bin.end()-1));
// now simulate removing the vertices
for (size_type i=0; i < num_vertices(g); ++i) {
vertex v = vert[i];
vis.examine_vertex(v,g);
v_cn = get(c,v);
typename graph_traits<Graph>::out_edge_iterator oi,oi_end;
for (boost::tie(oi,oi_end) = out_edges(v,g); oi!=oi_end; ++oi) {
vis.examine_edge(*oi,g);
vertex u = target(*oi,g);
// if c[u] > c[v], then u is still in the graph,
if (get(c,u) > v_cn) {
degree_type deg_u = get(c,u);
degree_type pos_u = get(pos,u);
// w is the first vertex with the same degree as u
// (this is the resort operation!)
degree_type pos_w = bin[deg_u];
vertex w = vert[pos_w];
if (u!=v) {
// swap u and w
put(pos,u,pos_w);
put(pos,w,pos_u);
vert[pos_w] = u;
vert[pos_u] = w;
}
// now, the vertices array is sorted assuming
// we perform the following step
// start the set of vertices with degree of u
// one into the future (this now points at vertex
// w which we swapped with u).
++bin[deg_u];
// we are removing v from the graph, so u's degree
// decreases
put(c,u,get(c,u)-1);
}
}
vis.finish_vertex(v,g);
}
return v_cn;
}
