[857] | 1 | //=======================================================================
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| 2 | // Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
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| 3 | // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
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| 4 | //
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| 5 | // Distributed under the Boost Software License, Version 1.0. (See
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| 6 | // accompanying file LICENSE_1_0.txt or copy at
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| 7 | // http://www.boost.org/LICENSE_1_0.txt)
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| 8 | //=======================================================================
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| 9 | //
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| 10 | #ifndef BOOST_GRAPH_MST_PRIM_HPP
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| 11 | #define BOOST_GRAPH_MST_PRIM_HPP
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| 12 |
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| 13 | #include <functional>
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| 14 | #include <boost/graph/graph_traits.hpp>
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| 15 | #include <boost/graph/dijkstra_shortest_paths.hpp>
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| 16 |
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| 17 | namespace boost {
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| 18 |
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| 19 | namespace detail {
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| 20 | // this should be somewhere else in boost...
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| 21 | template <class U, class V> struct _project2nd {
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| 22 | V operator()(U, V v) const { return v; }
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| 23 | };
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| 24 | }
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| 25 |
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| 26 | namespace detail {
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| 27 |
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| 28 | // This is Prim's algorithm to calculate the Minimum Spanning Tree
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| 29 | // for an undirected graph with weighted edges.
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| 30 |
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| 31 | template <class Graph, class P, class T, class R, class Weight>
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| 32 | inline void
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| 33 | prim_mst_impl(const Graph& G,
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| 34 | typename graph_traits<Graph>::vertex_descriptor s,
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| 35 | const bgl_named_params<P,T,R>& params,
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| 36 | Weight)
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| 37 | {
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| 38 | typedef typename property_traits<Weight>::value_type W;
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| 39 | std::less<W> compare;
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| 40 | detail::_project2nd<W,W> combine;
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| 41 | dijkstra_shortest_paths(G, s, params.distance_compare(compare).
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| 42 | distance_combine(combine));
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| 43 | }
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| 44 | } // namespace detail
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| 45 |
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| 46 | template <class VertexListGraph, class DijkstraVisitor,
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| 47 | class PredecessorMap, class DistanceMap,
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| 48 | class WeightMap, class IndexMap>
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| 49 | inline void
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| 50 | prim_minimum_spanning_tree
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| 51 | (const VertexListGraph& g,
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| 52 | typename graph_traits<VertexListGraph>::vertex_descriptor s,
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| 53 | PredecessorMap predecessor, DistanceMap distance, WeightMap weight,
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| 54 | IndexMap index_map,
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| 55 | DijkstraVisitor vis)
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| 56 | {
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| 57 | typedef typename property_traits<WeightMap>::value_type W;
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| 58 | std::less<W> compare;
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| 59 | detail::_project2nd<W,W> combine;
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| 60 | dijkstra_shortest_paths(g, s, predecessor, distance, weight, index_map,
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| 61 | compare, combine, (std::numeric_limits<W>::max)(), 0,
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| 62 | vis);
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| 63 | }
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| 64 |
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| 65 | template <class VertexListGraph, class PredecessorMap,
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| 66 | class P, class T, class R>
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| 67 | inline void prim_minimum_spanning_tree
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| 68 | (const VertexListGraph& g,
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| 69 | PredecessorMap p_map,
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| 70 | const bgl_named_params<P,T,R>& params)
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| 71 | {
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| 72 | detail::prim_mst_impl
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| 73 | (g,
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| 74 | choose_param(get_param(params, root_vertex_t()), *vertices(g).first),
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| 75 | params.predecessor_map(p_map),
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| 76 | choose_const_pmap(get_param(params, edge_weight), g, edge_weight));
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| 77 | }
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| 78 |
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| 79 | template <class VertexListGraph, class PredecessorMap>
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| 80 | inline void prim_minimum_spanning_tree
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| 81 | (const VertexListGraph& g, PredecessorMap p_map)
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| 82 | {
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| 83 | detail::prim_mst_impl
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| 84 | (g, *vertices(g).first, predecessor_map(p_map).
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| 85 | weight_map(get(edge_weight, g)),
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| 86 | get(edge_weight, g));
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| 87 | }
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| 88 |
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| 89 | } // namespace boost
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| 90 |
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| 91 | #endif // BOOST_GRAPH_MST_PRIM_HPP
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