sl@0: 
sl@0: 
sl@0: //
sl@0: //=======================================================================
sl@0: // Copyright (c) 2004 Kristopher Beevers
sl@0: //
sl@0: // Distributed under the Boost Software License, Version 1.0. (See
sl@0: // accompanying file LICENSE_1_0.txt or copy at
sl@0: // http://www.boost.org/LICENSE_1_0.txt)
sl@0: //=======================================================================
sl@0: //
sl@0: 
sl@0: #ifndef BOOST_GRAPH_ASTAR_SEARCH_HPP
sl@0: #define BOOST_GRAPH_ASTAR_SEARCH_HPP
sl@0: 
sl@0: 
sl@0: #include <functional>
sl@0: #include <boost/limits.hpp>
sl@0: #include <boost/graph/named_function_params.hpp>
sl@0: #include <boost/pending/mutable_queue.hpp>
sl@0: #include <boost/graph/relax.hpp>
sl@0: #include <boost/pending/indirect_cmp.hpp>
sl@0: #include <boost/graph/exception.hpp>
sl@0: #include <boost/graph/breadth_first_search.hpp>
sl@0: 
sl@0: 
sl@0: namespace boost {
sl@0: 
sl@0:   
sl@0:   template <class Heuristic, class Graph>
sl@0:   struct AStarHeuristicConcept {
sl@0:     void constraints()
sl@0:     {
sl@0:       function_requires< CopyConstructibleConcept<Heuristic> >();
sl@0:       h(u);
sl@0:     }
sl@0:     Heuristic h;
sl@0:     typename graph_traits<Graph>::vertex_descriptor u;
sl@0:   };
sl@0:   
sl@0:   
sl@0:   template <class Graph, class CostType>
sl@0:   class astar_heuristic : public std::unary_function<
sl@0:     typename graph_traits<Graph>::vertex_descriptor, CostType>
sl@0:   {
sl@0:   public:
sl@0:     typedef typename graph_traits<Graph>::vertex_descriptor Vertex;
sl@0:     astar_heuristic() {}
sl@0:     CostType operator()(Vertex u) { return static_cast<CostType>(0); }
sl@0:   };
sl@0:   
sl@0: 
sl@0:   
sl@0:   template <class Visitor, class Graph>
sl@0:   struct AStarVisitorConcept {
sl@0:     void constraints()
sl@0:     {
sl@0:       function_requires< CopyConstructibleConcept<Visitor> >();
sl@0:       vis.initialize_vertex(u, g);
sl@0:       vis.discover_vertex(u, g);
sl@0:       vis.examine_vertex(u, g);
sl@0:       vis.examine_edge(e, g);
sl@0:       vis.edge_relaxed(e, g);
sl@0:       vis.edge_not_relaxed(e, g);
sl@0:       vis.black_target(e, g);
sl@0:       vis.finish_vertex(u, g);
sl@0:     }
sl@0:     Visitor vis;
sl@0:     Graph g;
sl@0:     typename graph_traits<Graph>::vertex_descriptor u;
sl@0:     typename graph_traits<Graph>::edge_descriptor e;
sl@0:   };
sl@0:   
sl@0:   
sl@0:   template <class Visitors = null_visitor>
sl@0:   class astar_visitor : public bfs_visitor<Visitors> {
sl@0:   public:
sl@0:     astar_visitor() {}
sl@0:     astar_visitor(Visitors vis)
sl@0:       : bfs_visitor<Visitors>(vis) {}
sl@0:   
sl@0:     template <class Edge, class Graph>
sl@0:     void edge_relaxed(Edge e, Graph& g) {
sl@0:       invoke_visitors(this->m_vis, e, g, on_edge_relaxed());
sl@0:     }
sl@0:     template <class Edge, class Graph>
sl@0:     void edge_not_relaxed(Edge e, Graph& g) {
sl@0:       invoke_visitors(this->m_vis, e, g, on_edge_not_relaxed());      
sl@0:     }
sl@0:   private:
sl@0:     template <class Edge, class Graph>
sl@0:     void tree_edge(Edge e, Graph& g) {}
sl@0:     template <class Edge, class Graph>
sl@0:     void non_tree_edge(Edge e, Graph& g) {}
sl@0:   };
sl@0:   template <class Visitors>
sl@0:   astar_visitor<Visitors>
sl@0:   make_astar_visitor(Visitors vis) {
sl@0:     return astar_visitor<Visitors>(vis);
sl@0:   }
sl@0:   typedef astar_visitor<> default_astar_visitor;
sl@0:   
sl@0: 
sl@0:   namespace detail {
sl@0:     
sl@0:     template <class AStarHeuristic, class UniformCostVisitor,
sl@0:               class UpdatableQueue, class PredecessorMap,
sl@0:               class CostMap, class DistanceMap, class WeightMap,
sl@0:               class ColorMap, class BinaryFunction,
sl@0:               class BinaryPredicate>
sl@0:     struct astar_bfs_visitor
sl@0:     {
sl@0:       
sl@0:       typedef typename property_traits<CostMap>::value_type C;
sl@0:       typedef typename property_traits<ColorMap>::value_type ColorValue;
sl@0:       typedef color_traits<ColorValue> Color;
sl@0:       typedef typename property_traits<DistanceMap>::value_type distance_type;
sl@0:       
sl@0:       astar_bfs_visitor(AStarHeuristic h, UniformCostVisitor vis,
sl@0:                         UpdatableQueue& Q, PredecessorMap p,
sl@0:                         CostMap c, DistanceMap d, WeightMap w,
sl@0:                         ColorMap col, BinaryFunction combine,
sl@0:                         BinaryPredicate compare, C zero)
sl@0:         : m_h(h), m_vis(vis), m_Q(Q), m_predecessor(p), m_cost(c),
sl@0:           m_distance(d), m_weight(w), m_color(col),
sl@0:           m_combine(combine), m_compare(compare), m_zero(zero) {}
sl@0:       
sl@0:       
sl@0:       template <class Vertex, class Graph>
sl@0:       void initialize_vertex(Vertex u, Graph& g) {
sl@0:         m_vis.initialize_vertex(u, g);
sl@0:       }
sl@0:       template <class Vertex, class Graph>
sl@0:       void discover_vertex(Vertex u, Graph& g) {
sl@0:         m_vis.discover_vertex(u, g);
sl@0:       }
sl@0:       template <class Vertex, class Graph>
sl@0:       void examine_vertex(Vertex u, Graph& g) {
sl@0:         m_vis.examine_vertex(u, g);
sl@0:       }
sl@0:       template <class Vertex, class Graph>
sl@0:       void finish_vertex(Vertex u, Graph& g) {
sl@0:         m_vis.finish_vertex(u, g);
sl@0:       }
sl@0:       template <class Edge, class Graph>
sl@0:       void examine_edge(Edge e, Graph& g) { 
sl@0:         if (m_compare(get(m_weight, e), m_zero))
sl@0:           throw negative_edge();
sl@0:         m_vis.examine_edge(e, g);
sl@0:       }
sl@0:       template <class Edge, class Graph>
sl@0:       void non_tree_edge(Edge, Graph&) {}
sl@0:       
sl@0:       
sl@0:       
sl@0:       template <class Edge, class Graph>
sl@0:       void tree_edge(Edge e, Graph& g) {
sl@0:         m_decreased = relax(e, g, m_weight, m_predecessor, m_distance,
sl@0:                             m_combine, m_compare);
sl@0: 
sl@0:         if(m_decreased) {
sl@0:           m_vis.edge_relaxed(e, g);
sl@0:           put(m_cost, target(e, g),
sl@0:               m_combine(get(m_distance, target(e, g)),
sl@0:                         m_h(target(e, g))));
sl@0:         } else
sl@0:           m_vis.edge_not_relaxed(e, g);
sl@0:       }
sl@0:       
sl@0:       
sl@0:       template <class Edge, class Graph>
sl@0:       void gray_target(Edge e, Graph& g) {
sl@0:         distance_type old_distance = get(m_distance, target(e, g));
sl@0: 
sl@0:         m_decreased = relax(e, g, m_weight, m_predecessor, m_distance,
sl@0:                             m_combine, m_compare);
sl@0: 
sl@0:         /* On x86 Linux with optimization, we sometimes get into a
sl@0:            horrible case where m_decreased is true but the distance hasn't
sl@0:            actually changed. This occurs when the comparison inside
sl@0:            relax() occurs with the 80-bit precision of the x87 floating
sl@0:            point unit, but the difference is lost when the resulting
sl@0:            values are written back to lower-precision memory (e.g., a
sl@0:            double). With the eager Dijkstra's implementation, this results
sl@0:            in looping. */
sl@0:         if(m_decreased && old_distance != get(m_distance, target(e, g))) {
sl@0:           put(m_cost, target(e, g),
sl@0:               m_combine(get(m_distance, target(e, g)),
sl@0:                         m_h(target(e, g))));
sl@0:           m_Q.update(target(e, g));
sl@0:           m_vis.edge_relaxed(e, g);
sl@0:         } else
sl@0:           m_vis.edge_not_relaxed(e, g);
sl@0:       }
sl@0:       
sl@0:       
sl@0:       template <class Edge, class Graph>
sl@0:       void black_target(Edge e, Graph& g) {
sl@0:         distance_type old_distance = get(m_distance, target(e, g));
sl@0: 
sl@0:         m_decreased = relax(e, g, m_weight, m_predecessor, m_distance,
sl@0:                             m_combine, m_compare);
sl@0: 
sl@0:         /* See comment in gray_target */
sl@0:         if(m_decreased && old_distance != get(m_distance, target(e, g))) {
sl@0:           m_vis.edge_relaxed(e, g);
sl@0:           put(m_cost, target(e, g),
sl@0:               m_combine(get(m_distance, target(e, g)),
sl@0:                         m_h(target(e, g))));
sl@0:           m_Q.push(target(e, g));
sl@0:           put(m_color, target(e, g), Color::gray());
sl@0:           m_vis.black_target(e, g);
sl@0:         } else
sl@0:           m_vis.edge_not_relaxed(e, g);
sl@0:       }
sl@0:       
sl@0:       
sl@0:       
sl@0:       AStarHeuristic m_h;
sl@0:       UniformCostVisitor m_vis;
sl@0:       UpdatableQueue& m_Q;
sl@0:       PredecessorMap m_predecessor;
sl@0:       CostMap m_cost;
sl@0:       DistanceMap m_distance;
sl@0:       WeightMap m_weight;
sl@0:       ColorMap m_color;
sl@0:       BinaryFunction m_combine;
sl@0:       BinaryPredicate m_compare;
sl@0:       bool m_decreased;
sl@0:       C m_zero;
sl@0:       
sl@0:     };
sl@0:     
sl@0:   } // namespace detail
sl@0: 
sl@0:   
sl@0:   
sl@0:   template <typename VertexListGraph, typename AStarHeuristic,
sl@0:             typename AStarVisitor, typename PredecessorMap,
sl@0:             typename CostMap, typename DistanceMap,
sl@0:             typename WeightMap, typename ColorMap,
sl@0:             typename VertexIndexMap,
sl@0:             typename CompareFunction, typename CombineFunction,
sl@0:             typename CostInf, typename CostZero>
sl@0:   inline void
sl@0:   astar_search_no_init
sl@0:     (VertexListGraph &g,
sl@0:      typename graph_traits<VertexListGraph>::vertex_descriptor s,
sl@0:      AStarHeuristic h, AStarVisitor vis,
sl@0:      PredecessorMap predecessor, CostMap cost,
sl@0:      DistanceMap distance, WeightMap weight,
sl@0:      ColorMap color, VertexIndexMap index_map,
sl@0:      CompareFunction compare, CombineFunction combine,
sl@0:      CostInf inf, CostZero zero)
sl@0:   {
sl@0:     typedef indirect_cmp<CostMap, CompareFunction> IndirectCmp;
sl@0:     IndirectCmp icmp(cost, compare);
sl@0:   
sl@0:     typedef typename graph_traits<VertexListGraph>::vertex_descriptor
sl@0:       Vertex;
sl@0:     typedef mutable_queue<Vertex, std::vector<Vertex>,
sl@0:         IndirectCmp, VertexIndexMap>
sl@0:       MutableQueue;
sl@0:     MutableQueue Q(num_vertices(g), icmp, index_map);
sl@0:   
sl@0:     detail::astar_bfs_visitor<AStarHeuristic, AStarVisitor,
sl@0:         MutableQueue, PredecessorMap, CostMap, DistanceMap,
sl@0:         WeightMap, ColorMap, CombineFunction, CompareFunction>
sl@0:       bfs_vis(h, vis, Q, predecessor, cost, distance, weight,
sl@0:               color, combine, compare, zero);
sl@0:   
sl@0:     breadth_first_visit(g, s, Q, bfs_vis, color);
sl@0:   }
sl@0:   
sl@0:   
sl@0:   // Non-named parameter interface
sl@0:   template <typename VertexListGraph, typename AStarHeuristic,
sl@0:             typename AStarVisitor, typename PredecessorMap,
sl@0:             typename CostMap, typename DistanceMap,
sl@0:             typename WeightMap, typename VertexIndexMap,
sl@0:             typename ColorMap,
sl@0:             typename CompareFunction, typename CombineFunction,
sl@0:             typename CostInf, typename CostZero>
sl@0:   inline void
sl@0:   astar_search
sl@0:     (VertexListGraph &g,
sl@0:      typename graph_traits<VertexListGraph>::vertex_descriptor s,
sl@0:      AStarHeuristic h, AStarVisitor vis,
sl@0:      PredecessorMap predecessor, CostMap cost,
sl@0:      DistanceMap distance, WeightMap weight,
sl@0:      VertexIndexMap index_map, ColorMap color,
sl@0:      CompareFunction compare, CombineFunction combine,
sl@0:      CostInf inf, CostZero zero)
sl@0:   {
sl@0:     
sl@0:     typedef typename property_traits<ColorMap>::value_type ColorValue;
sl@0:     typedef color_traits<ColorValue> Color;
sl@0:     typename graph_traits<VertexListGraph>::vertex_iterator ui, ui_end;
sl@0:     for (tie(ui, ui_end) = vertices(g); ui != ui_end; ++ui) {
sl@0:       put(color, *ui, Color::white());
sl@0:       put(distance, *ui, inf);
sl@0:       put(cost, *ui, inf);
sl@0:       put(predecessor, *ui, *ui);
sl@0:       vis.initialize_vertex(*ui, g);
sl@0:     }
sl@0:     put(distance, s, zero);
sl@0:     put(cost, s, h(s));
sl@0:     
sl@0:     astar_search_no_init
sl@0:       (g, s, h, vis, predecessor, cost, distance, weight,
sl@0:        color, index_map, compare, combine, inf, zero);
sl@0:     
sl@0:   }
sl@0:   
sl@0:   
sl@0:   
sl@0:   namespace detail {
sl@0:     template <class VertexListGraph, class AStarHeuristic,
sl@0:               class CostMap, class DistanceMap, class WeightMap,
sl@0:               class IndexMap, class ColorMap, class Params>
sl@0:     inline void
sl@0:     astar_dispatch2
sl@0:       (VertexListGraph& g,
sl@0:        typename graph_traits<VertexListGraph>::vertex_descriptor s,
sl@0:        AStarHeuristic h, CostMap cost, DistanceMap distance,
sl@0:        WeightMap weight, IndexMap index_map, ColorMap color,
sl@0:        const Params& params)
sl@0:     {
sl@0:       dummy_property_map p_map;
sl@0:       typedef typename property_traits<CostMap>::value_type C;
sl@0:       astar_search
sl@0:         (g, s, h,
sl@0:          choose_param(get_param(params, graph_visitor),
sl@0:                       make_astar_visitor(null_visitor())),
sl@0:          choose_param(get_param(params, vertex_predecessor), p_map),
sl@0:          cost, distance, weight, index_map, color,
sl@0:          choose_param(get_param(params, distance_compare_t()),
sl@0:                       std::less<C>()),
sl@0:          choose_param(get_param(params, distance_combine_t()),
sl@0:                       closed_plus<C>()),
sl@0:          choose_param(get_param(params, distance_inf_t()),
sl@0:                       std::numeric_limits<C>::max BOOST_PREVENT_MACRO_SUBSTITUTION ()),
sl@0:          choose_param(get_param(params, distance_zero_t()),
sl@0:                       C()));
sl@0:     }
sl@0:   
sl@0:     template <class VertexListGraph, class AStarHeuristic,
sl@0:               class CostMap, class DistanceMap, class WeightMap,
sl@0:               class IndexMap, class ColorMap, class Params>
sl@0:     inline void
sl@0:     astar_dispatch1
sl@0:       (VertexListGraph& g,
sl@0:        typename graph_traits<VertexListGraph>::vertex_descriptor s,
sl@0:        AStarHeuristic h, CostMap cost, DistanceMap distance,
sl@0:        WeightMap weight, IndexMap index_map, ColorMap color,
sl@0:        const Params& params)
sl@0:     {
sl@0:       typedef typename property_traits<WeightMap>::value_type D;
sl@0:       typename std::vector<D>::size_type
sl@0:         n = is_default_param(distance) ? num_vertices(g) : 1;
sl@0:       std::vector<D> distance_map(n);
sl@0:       n = is_default_param(cost) ? num_vertices(g) : 1;
sl@0:       std::vector<D> cost_map(n);
sl@0:       std::vector<default_color_type> color_map(num_vertices(g));
sl@0:       default_color_type c = white_color;
sl@0:   
sl@0:       detail::astar_dispatch2
sl@0:         (g, s, h,
sl@0:          choose_param(cost, make_iterator_property_map
sl@0:                       (cost_map.begin(), index_map,
sl@0:                        cost_map[0])),
sl@0:          choose_param(distance, make_iterator_property_map
sl@0:                       (distance_map.begin(), index_map, 
sl@0:                        distance_map[0])),
sl@0:          weight, index_map,
sl@0:          choose_param(color, make_iterator_property_map
sl@0:                       (color_map.begin(), index_map, c)),
sl@0:          params);
sl@0:     }
sl@0:   } // namespace detail
sl@0:   
sl@0:   
sl@0:   // Named parameter interface
sl@0:   template <typename VertexListGraph,
sl@0:             typename AStarHeuristic,
sl@0:             typename P, typename T, typename R>
sl@0:   void
sl@0:   astar_search
sl@0:     (VertexListGraph &g,
sl@0:      typename graph_traits<VertexListGraph>::vertex_descriptor s,
sl@0:      AStarHeuristic h, const bgl_named_params<P, T, R>& params)
sl@0:   {
sl@0:     
sl@0:     detail::astar_dispatch1
sl@0:       (g, s, h,
sl@0:        get_param(params, vertex_rank),
sl@0:        get_param(params, vertex_distance),
sl@0:        choose_const_pmap(get_param(params, edge_weight), g, edge_weight),
sl@0:        choose_const_pmap(get_param(params, vertex_index), g, vertex_index),
sl@0:        get_param(params, vertex_color),
sl@0:        params);
sl@0:     
sl@0:   }
sl@0:   
sl@0: } // namespace boost
sl@0: 
sl@0: #endif // BOOST_GRAPH_ASTAR_SEARCH_HPP