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//======================================================================= // Copyright 1997, 1998, 1999, 2000 University of Notre Dame. // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek // // 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) //======================================================================= /* This file implements the function template <class VertexAndEdgeListGraph, class DistanceMatrix, class P, class T, class R> bool johnson_all_pairs_shortest_paths (VertexAndEdgeListGraph& g, DistanceMatrix& D, const bgl_named_params<P, T, R>& params) */ #ifndef BOOST_GRAPH_JOHNSON_HPP #define BOOST_GRAPH_JOHNSON_HPP #include <boost/graph/graph_traits.hpp> #include <boost/property_map.hpp> #include <boost/graph/bellman_ford_shortest_paths.hpp> #include <boost/graph/dijkstra_shortest_paths.hpp> #include <boost/graph/adjacency_list.hpp> #include <boost/pending/ct_if.hpp> #include <boost/type_traits/same_traits.hpp> namespace boost { template <class VertexAndEdgeListGraph, class DistanceMatrix, class VertexID, class Weight, class DistanceZero> bool johnson_all_pairs_shortest_paths(VertexAndEdgeListGraph& g1, DistanceMatrix& D, VertexID id1, Weight w1, DistanceZero zero) { typedef graph_traits<VertexAndEdgeListGraph> Traits1; typedef typename property_traits<Weight>::value_type DT; function_requires< BasicMatrixConcept<DistanceMatrix, typename Traits1::vertices_size_type, DT> >(); typedef typename Traits1::directed_category DirCat; bool is_undirected = is_same<DirCat, undirected_tag>::value; typedef adjacency_list<vecS, vecS, directedS, property< vertex_distance_t, DT>, property< edge_weight_t, DT, property< edge_weight2_t, DT > > > Graph2; typedef graph_traits<Graph2> Traits2; Graph2 g2(num_vertices(g1) + 1); typename property_map<Graph2, edge_weight_t>::type w = get(edge_weight, g2); typename property_map<Graph2, edge_weight2_t>::type w_hat = get(edge_weight2, g2); typename property_map<Graph2, vertex_distance_t>::type d = get(vertex_distance, g2); typedef typename property_map<Graph2, vertex_index_t>::type VertexID2; VertexID2 id2 = get(vertex_index, g2); // Construct g2 where V[g2] = V[g1] U {s} // and E[g2] = E[g1] U {(s,v)| v in V[g1]} std::vector<typename Traits1::vertex_descriptor> verts1(num_vertices(g1) + 1); typename Traits2::vertex_descriptor s = *vertices(g2).first; { typename Traits1::vertex_iterator v, v_end; int i = 1; for (tie(v, v_end) = vertices(g1); v != v_end; ++v, ++i) { typename Traits2::edge_descriptor e; bool z; tie(e, z) = add_edge(s, get(id1, *v) + 1, g2); put(w, e, zero); verts1[i] = *v; } typename Traits1::edge_iterator e, e_end; for (tie(e, e_end) = edges(g1); e != e_end; ++e) { typename Traits2::edge_descriptor e2; bool z; tie(e2, z) = add_edge(get(id1, source(*e, g1)) + 1, get(id1, target(*e, g1)) + 1, g2); put(w, e2, get(w1, *e)); if (is_undirected) { tie(e2, z) = add_edge(get(id1, target(*e, g1)) + 1, get(id1, source(*e, g1)) + 1, g2); put(w, e2, get(w1, *e)); } } } typename Traits2::vertex_iterator v, v_end, u, u_end; typename Traits2::edge_iterator e, e_end; std::vector<DT> h_vec(num_vertices(g2)); typedef typename std::vector<DT>::iterator iter_t; iterator_property_map<iter_t,VertexID2,DT,DT&> h(h_vec.begin(), id2); DT inf = (std::numeric_limits<DT>::max)(); for (tie(v, v_end) = vertices(g2); v != v_end; ++v) d[*v] = inf; put(d, s, zero); // Using the non-named parameter versions of bellman_ford and // dijkstra for portability reasons. dummy_property_map pred; closed_plus<DT> combine; std::less<DT> compare; bellman_visitor<> bvis; if (bellman_ford_shortest_paths (g2, num_vertices(g2), w, pred, d, combine, compare, bvis)) { for (tie(v, v_end) = vertices(g2); v != v_end; ++v) put(h, *v, get(d, *v)); // Reweight the edges to remove negatives for (tie(e, e_end) = edges(g2); e != e_end; ++e) { typename Traits2::vertex_descriptor a = source(*e, g2), b = target(*e, g2); put(w_hat, *e, get(w, *e) + get(h, a) - get(h, b)); } for (tie(u, u_end) = vertices(g2); u != u_end; ++u) { dijkstra_visitor<> dvis; dijkstra_shortest_paths (g2, *u, pred, d, w_hat, id2, compare, combine, inf, zero,dvis); for (tie(v, v_end) = vertices(g2); v != v_end; ++v) { if (*u != s && *v != s) { typename Traits1::vertex_descriptor u1, v1; u1 = verts1[id2[*u]]; v1 = verts1[id2[*v]]; D[id2[*u]-1][id2[*v]-1] = get(d, *v) + get(h, *v) - get(h, *u); } } } return true; } else return false; } namespace detail { template <class VertexAndEdgeListGraph, class DistanceMatrix, class P, class T, class R, class Weight, class VertexID> bool johnson_dispatch(VertexAndEdgeListGraph& g, DistanceMatrix& D, const bgl_named_params<P, T, R>& params, Weight w, VertexID id) { typedef typename property_traits<Weight>::value_type WT; return johnson_all_pairs_shortest_paths (g, D, id, w, choose_param(get_param(params, distance_zero_t()), WT()) ); } } // namespace detail template <class VertexAndEdgeListGraph, class DistanceMatrix, class P, class T, class R> bool johnson_all_pairs_shortest_paths (VertexAndEdgeListGraph& g, DistanceMatrix& D, const bgl_named_params<P, T, R>& params) { return detail::johnson_dispatch (g, D, params, choose_const_pmap(get_param(params, edge_weight), g, edge_weight), choose_const_pmap(get_param(params, vertex_index), g, vertex_index) ); } template <class VertexAndEdgeListGraph, class DistanceMatrix> bool johnson_all_pairs_shortest_paths (VertexAndEdgeListGraph& g, DistanceMatrix& D) { bgl_named_params<int,int> params(1); return detail::johnson_dispatch (g, D, params, get(edge_weight, g), get(vertex_index, g)); } } // namespace boost #endif // BOOST_GRAPH_JOHNSON_HPP