Edit: /usr/include/boost/graph/core_numbers.hpp (13663B)
//
//=======================================================================
// Copyright 2007 Stanford University
// Authors: David Gleich
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
//
#ifndef BOOST_GRAPH_CORE_NUMBERS_HPP
#define BOOST_GRAPH_CORE_NUMBERS_HPP
#include
#include
#include
#include
/*
* core_numbers
*
* Requirement: IncidenceGraph
*/
// History
//
// 30 July 2007
// Added visitors to the implementation
//
// 8 February 2008
// Fixed headers and missing typename
namespace boost
{
// A linear time O(m) algorithm to compute the indegree core number
// of a graph for unweighted graphs.
//
// and a O((n+m) log n) algorithm to compute the in-edge-weight core
// numbers of a weighted graph.
//
// The linear algorithm comes from:
// Vladimir Batagelj and Matjaz Zaversnik, "An O(m) Algorithm for Cores
// Decomposition of Networks." Sept. 1 2002.
template < typename Visitor, typename Graph > struct CoreNumbersVisitorConcept
{
void constraints()
{
BOOST_CONCEPT_ASSERT((CopyConstructibleConcept< Visitor >));
vis.examine_vertex(u, g);
vis.finish_vertex(u, g);
vis.examine_edge(e, g);
}
Visitor vis;
Graph g;
typename graph_traits< Graph >::vertex_descriptor u;
typename graph_traits< Graph >::edge_descriptor e;
};
template < class Visitors = null_visitor >
class core_numbers_visitor : public bfs_visitor< Visitors >
{
public:
core_numbers_visitor() {}
core_numbers_visitor(Visitors vis) : bfs_visitor< Visitors >(vis) {}
private:
template < class Vertex, class Graph >
void initialize_vertex(Vertex, Graph&)
{
}
template < class Vertex, class Graph > void discover_vertex(Vertex, Graph&)
{
}
template < class Vertex, class Graph > void gray_target(Vertex, Graph&) {}
template < class Vertex, class Graph > void black_target(Vertex, Graph&) {}
template < class Edge, class Graph > void tree_edge(Edge, Graph&) {}
template < class Edge, class Graph > void non_tree_edge(Edge, Graph&) {}
};
template < class Visitors >
core_numbers_visitor< Visitors > make_core_numbers_visitor(Visitors vis)
{
return core_numbers_visitor< Visitors >(vis);
}
typedef core_numbers_visitor<> default_core_numbers_visitor;
namespace detail
{
// implement a constant_property_map to simplify compute_in_degree
// for the weighted and unweighted case
// this is based on dummy property map
template < typename ValueType >
class constant_value_property_map
: public boost::put_get_helper< ValueType,
constant_value_property_map< ValueType > >
{
public:
typedef void key_type;
typedef ValueType value_type;
typedef const ValueType& reference;
typedef boost::readable_property_map_tag category;
inline constant_value_property_map(ValueType cc) : c(cc) {}
inline constant_value_property_map(
const constant_value_property_map< ValueType >& x)
: c(x.c)
{
}
template < class Vertex > inline reference operator[](Vertex) const
{
return c;
}
protected:
ValueType c;
};
// the core numbers start as the indegree or inweight. This function
// will initialize these values
template < typename Graph, typename CoreMap, typename EdgeWeightMap >
void compute_in_degree_map(Graph& g, CoreMap d, EdgeWeightMap wm)
{
typename graph_traits< Graph >::vertex_iterator vi, vi_end;
typename graph_traits< Graph >::out_edge_iterator ei, ei_end;
for (boost::tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
{
put(d, *vi, 0);
}
for (boost::tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
{
for (boost::tie(ei, ei_end) = out_edges(*vi, g); ei != ei_end; ++ei)
{
put(d, target(*ei, g), get(d, target(*ei, g)) + get(wm, *ei));
}
}
}
// the version for weighted graphs is a little different
template < typename Graph, typename CoreMap, typename EdgeWeightMap,
typename MutableQueue, typename Visitor >
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);
}
template < typename Graph, typename CoreMap, typename EdgeWeightMap,
typename IndexMap, typename CoreNumVisitor >
typename property_traits< CoreMap >::value_type core_numbers_dispatch(
Graph& g, CoreMap c, EdgeWeightMap wm, IndexMap im, CoreNumVisitor vis)
{
typedef typename property_traits< CoreMap >::value_type D;
typedef std::less< D > Cmp;
// build the mutable queue
typedef typename graph_traits< Graph >::vertex_descriptor vertex;
std::vector< std::size_t > index_in_heap_data(num_vertices(g));
typedef iterator_property_map< std::vector< std::size_t >::iterator,
IndexMap >
index_in_heap_map_type;
index_in_heap_map_type index_in_heap_map(
index_in_heap_data.begin(), im);
typedef d_ary_heap_indirect< vertex, 4, index_in_heap_map_type, CoreMap,
Cmp >
MutableQueue;
MutableQueue Q(c, index_in_heap_map, Cmp());
typename graph_traits< Graph >::vertex_iterator vi, vi_end;
for (boost::tie(vi, vi_end) = vertices(g); vi != vi_end; ++vi)
{
Q.push(*vi);
}
return core_numbers_impl(g, c, wm, Q, vis);
}
// the version for the unweighted case
// for this functions CoreMap must be initialized
// with the in degree of each vertex
template < typename Graph, typename CoreMap, typename PositionMap,
typename Visitor >
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;
}
} // namespace detail
// non-named parameter version for the unweighted case
template < typename Graph, typename CoreMap, typename CoreNumVisitor >
typename property_traits< CoreMap >::value_type core_numbers(
Graph& g, CoreMap c, CoreNumVisitor vis)
{
typedef typename graph_traits< Graph >::vertices_size_type size_type;
detail::compute_in_degree_map(g, c,
detail::constant_value_property_map<
typename property_traits< CoreMap >::value_type >(1));
return detail::core_numbers_impl(g, c,
make_iterator_property_map(
std::vector< size_type >(num_vertices(g)).begin(),
get(vertex_index, g)),
vis);
}
// non-named paramter version for the unweighted case
template < typename Graph, typename CoreMap >
typename property_traits< CoreMap >::value_type core_numbers(
Graph& g, CoreMap c)
{
return core_numbers(g, c, make_core_numbers_visitor(null_visitor()));
}
// non-named parameter version for the weighted case
template < typename Graph, typename CoreMap, typename EdgeWeightMap,
typename VertexIndexMap, typename CoreNumVisitor >
typename property_traits< CoreMap >::value_type core_numbers(Graph& g,
CoreMap c, EdgeWeightMap wm, VertexIndexMap vim, CoreNumVisitor vis)
{
detail::compute_in_degree_map(g, c, wm);
return detail::core_numbers_dispatch(g, c, wm, vim, vis);
}
// non-named parameter version for the weighted case
// template
// typename property_traits::value_type
// core_numbers(Graph& g, CoreMap c, EdgeWeightMap wm)
// {
// typedef typename graph_traits::vertices_size_type size_type;
// detail::compute_in_degree_map(g,c,wm);
// return detail::core_numbers_dispatch(g,c,wm,get(vertex_index,g),
// make_core_numbers_visitor(null_visitor()));
// }
template < typename Graph, typename CoreMap >
typename property_traits< CoreMap >::value_type weighted_core_numbers(
Graph& g, CoreMap c)
{
return weighted_core_numbers(
g, c, make_core_numbers_visitor(null_visitor()));
}
template < typename Graph, typename CoreMap, typename CoreNumVisitor >
typename property_traits< CoreMap >::value_type weighted_core_numbers(
Graph& g, CoreMap c, CoreNumVisitor vis)
{
return core_numbers(g, c, get(edge_weight, g), get(vertex_index, g), vis);
}
} // namespace boost
#endif // BOOST_GRAPH_CORE_NUMBERS_HPP