92 lines
3.0 KiB
C++
92 lines
3.0 KiB
C++
//=======================================================================
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// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
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// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//=======================================================================
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//
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#ifndef BOOST_GRAPH_MST_PRIM_HPP
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#define BOOST_GRAPH_MST_PRIM_HPP
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#include <functional>
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#include <boost/graph/graph_traits.hpp>
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#include <boost/graph/dijkstra_shortest_paths.hpp>
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namespace boost {
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namespace detail {
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// this should be somewhere else in boost...
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template <class U, class V> struct _project2nd {
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V operator()(U, V v) const { return v; }
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};
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}
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namespace detail {
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// This is Prim's algorithm to calculate the Minimum Spanning Tree
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// for an undirected graph with weighted edges.
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template <class Graph, class P, class T, class R, class Weight>
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inline void
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prim_mst_impl(const Graph& G,
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typename graph_traits<Graph>::vertex_descriptor s,
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const bgl_named_params<P,T,R>& params,
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Weight)
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{
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typedef typename property_traits<Weight>::value_type W;
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std::less<W> compare;
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detail::_project2nd<W,W> combine;
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dijkstra_shortest_paths(G, s, params.distance_compare(compare).
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distance_combine(combine));
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}
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} // namespace detail
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template <class VertexListGraph, class DijkstraVisitor,
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class PredecessorMap, class DistanceMap,
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class WeightMap, class IndexMap>
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inline void
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prim_minimum_spanning_tree
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(const VertexListGraph& g,
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typename graph_traits<VertexListGraph>::vertex_descriptor s,
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PredecessorMap predecessor, DistanceMap distance, WeightMap weight,
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IndexMap index_map,
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DijkstraVisitor vis)
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{
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typedef typename property_traits<WeightMap>::value_type W;
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std::less<W> compare;
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detail::_project2nd<W,W> combine;
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dijkstra_shortest_paths(g, s, predecessor, distance, weight, index_map,
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compare, combine, (std::numeric_limits<W>::max)(), 0,
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vis);
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}
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template <class VertexListGraph, class PredecessorMap,
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class P, class T, class R>
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inline void prim_minimum_spanning_tree
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(const VertexListGraph& g,
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PredecessorMap p_map,
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const bgl_named_params<P,T,R>& params)
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{
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detail::prim_mst_impl
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(g,
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choose_param(get_param(params, root_vertex_t()), *vertices(g).first),
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params.predecessor_map(p_map),
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choose_const_pmap(get_param(params, edge_weight), g, edge_weight));
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}
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template <class VertexListGraph, class PredecessorMap>
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inline void prim_minimum_spanning_tree
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(const VertexListGraph& g, PredecessorMap p_map)
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{
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detail::prim_mst_impl
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(g, *vertices(g).first, predecessor_map(p_map).
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weight_map(get(edge_weight, g)),
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get(edge_weight, g));
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}
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} // namespace boost
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#endif // BOOST_GRAPH_MST_PRIM_HPP
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