1 | /* |
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2 | * Shooting* Shortest path algorithm for PostgreSQL |
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3 | * |
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4 | * Copyright (c) 2007 Anton A. Patrushev, Orkney, Inc. |
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5 | * |
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6 | * This program is free software; you can redistribute it and/or modify |
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7 | * it under the terms of the GNU General Public License as published by |
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8 | * the Free Software Foundation; either version 2 of the License, or |
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9 | * (at your option) any later version. |
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10 | * |
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11 | * This program is distributed in the hope that it will be useful, |
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12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | * GNU General Public License for more details. |
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15 | * |
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16 | * You should have received a copy of the GNU General Public License |
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17 | * along with this program; if not, write to the Free Software |
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18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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19 | * |
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20 | */ |
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21 | |
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22 | #include <boost/config.hpp> |
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23 | |
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24 | #include <boost/graph/graph_traits.hpp> |
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25 | #include <boost/graph/adjacency_list.hpp> |
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26 | #include <boost/vector_property_map.hpp> |
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27 | #include <shooting_star_search.hpp> |
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28 | |
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29 | #include "shooting_star.h" |
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30 | |
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31 | #include <cmath> // for sqrt |
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32 | |
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33 | using namespace std; |
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34 | using namespace boost; |
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35 | |
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36 | struct Edge |
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37 | { |
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38 | int id; |
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39 | int source; |
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40 | int target; |
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41 | float8 cost; |
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42 | float distance; |
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43 | float rank; |
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44 | std::map< int, vector< std::pair<float, std::vector<int> > >, std::less<int> > adjacent_edges; |
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45 | default_color_type color; |
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46 | |
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47 | std::size_t index; |
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48 | }; |
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49 | |
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50 | struct Vertex |
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51 | { |
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52 | int id; |
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53 | float8 x; |
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54 | float8 y; |
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55 | }; |
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56 | |
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57 | // exception for termination |
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58 | template <class Edge> |
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59 | class found_goal |
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60 | { |
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61 | public: |
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62 | found_goal() {} |
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63 | found_goal(Edge target) : target_edge(target) {} |
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64 | found_goal(const found_goal &fg) {} |
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65 | ~found_goal() {} |
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66 | Edge get_target() |
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67 | { |
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68 | return target_edge; |
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69 | } |
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70 | private: |
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71 | Edge target_edge; |
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72 | }; |
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73 | |
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74 | |
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75 | // visitor that terminates when we find the goal |
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76 | template <class Edge> |
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77 | class shooting_star_goal_visitor : public boost::default_shooting_star_visitor |
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78 | { |
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79 | public: |
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80 | shooting_star_goal_visitor(Edge goal, int max_id) : m_goal(goal){} |
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81 | shooting_star_goal_visitor(const shooting_star_goal_visitor &gv) : m_goal(gv.m_goal){} |
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82 | ~shooting_star_goal_visitor(){} |
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83 | |
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84 | template <class Graph> |
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85 | void examine_edge(Edge e, Graph& g, int e_max_id) |
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86 | { |
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87 | if( g[e].id == g[m_goal].id || g[e].id == g[m_goal].id + e_max_id ) |
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88 | { |
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89 | throw found_goal<Edge>(e); |
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90 | } |
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91 | } |
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92 | template <class Graph> |
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93 | void finish_edge(Edge e, Graph& g) {} |
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94 | private: |
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95 | Edge m_goal; |
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96 | int e_max_id; |
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97 | }; |
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98 | |
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99 | // Heuristic function |
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100 | template <class Graph, class CostType> |
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101 | class distance_heuristic |
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102 | { |
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103 | public: |
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104 | typedef typename graph_traits<Graph>::edge_descriptor Edge; |
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105 | distance_heuristic(Graph& g, Edge goal):m_g(g), m_goal(goal){} |
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106 | CostType operator()(Edge e) |
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107 | { |
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108 | CostType dx = m_g[source(m_goal, m_g)].x - m_g[source(e, m_g)].x; |
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109 | CostType dxt = m_g[target(m_goal, m_g)].x - m_g[target(e, m_g)].x; |
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110 | CostType dy = m_g[source(m_goal, m_g)].y - m_g[source(e, m_g)].y; |
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111 | CostType dyt = m_g[target(m_goal, m_g)].y - m_g[target(e, m_g)].y; |
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112 | //You can choose any heuristical function from below |
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113 | //return ::max(dx, dy); |
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114 | //return ::sqrt(dx * dx + dy * dy)/2; |
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115 | //return 0; |
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116 | //return (min(::fabs(dx),::fabs(dxt))+min(::fabs(dy),::fabs(dyt)))/2; |
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117 | return sqrt(pow(min(::fabs(dx),::fabs(dxt)),2)+pow(min(::fabs(dy),::fabs(dyt)),2))/2; |
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118 | } |
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119 | private: |
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120 | Graph& m_g; |
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121 | Edge m_goal; |
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122 | }; |
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123 | |
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124 | |
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125 | // Adds an edge to the graph |
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126 | // Also copies all attributes and adjacent edges |
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127 | template <class G, class E> |
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128 | static void |
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129 | graph_add_edge(G &graph, int index, |
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130 | int id, int source, int target, |
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131 | float8 cost, float8 s_x, float8 s_y, float8 t_x, float8 t_y, |
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132 | std::map< int, vector< std::pair<float, vector<int> > >, std::less<int> > adjacent_edges) |
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133 | { |
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134 | |
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135 | E e; |
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136 | bool inserted; |
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137 | |
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138 | if (cost < 0) // edges are inserted as unpassable if cost is negative |
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139 | cost = MAX_COST; |
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140 | |
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141 | tie(e, inserted) = add_edge(source, target, graph); |
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142 | |
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143 | graph[e].cost = cost; |
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144 | graph[e].id = id; |
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145 | |
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146 | graph[e].source = source; |
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147 | graph[e].target = target; |
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148 | |
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149 | graph[e].adjacent_edges = adjacent_edges; |
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150 | |
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151 | graph[e].rank = 0; |
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152 | graph[e].distance = 0; |
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153 | |
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154 | graph[e].index = index; |
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155 | |
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156 | |
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157 | typedef typename graph_traits<G>::vertex_descriptor Vertex; |
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158 | Vertex s = vertex(source, graph); |
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159 | Vertex t = vertex(target, graph); |
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160 | |
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161 | graph[s].id=source; |
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162 | graph[t].id=target; |
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163 | |
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164 | graph[s].x=s_x; |
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165 | graph[s].y=s_y; |
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166 | graph[t].x=t_x; |
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167 | graph[t].y=t_y; |
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168 | |
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169 | } |
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170 | |
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171 | // Main Shooting* function. |
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172 | // It renumbers vertices, fills the graph with edges, |
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173 | // calculates a route and return a result. |
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174 | int |
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175 | boost_shooting_star(edge_shooting_star_t *edges_array, unsigned int count, |
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176 | int source_edge_id, int target_edge_id, |
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177 | bool directed, bool has_reverse_cost, |
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178 | path_element_t **path, int *path_count, char **err_msg, int e_max_id) |
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179 | { |
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180 | |
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181 | typedef adjacency_list<vecS, vecS, directedS, Vertex, Edge> graph_t; |
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182 | |
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183 | typedef graph_traits < graph_t >::vertex_descriptor vertex_descriptor; |
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184 | typedef graph_traits < graph_t >::edge_descriptor edge_descriptor; |
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185 | |
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186 | const unsigned int num_nodes = count*2; |
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187 | |
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188 | int z; |
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189 | int src, trg, offset, rule_num; |
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190 | |
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191 | graph_t graph(num_nodes); |
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192 | |
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193 | std::map< int, vector< std::pair<float, vector<int> > >, std::less<int> > adjacent_edges; |
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194 | |
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195 | std::map< int, int, std::less<int> > vertices; |
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196 | |
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197 | vector<int> rule; |
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198 | |
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199 | offset = 1; |
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200 | rule_num = 0; |
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201 | |
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202 | for (std::size_t j = 0; j < count; ++j) |
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203 | { |
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204 | //Vertex ids renumbering moved here |
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205 | src = edges_array[j].source; |
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206 | trg = edges_array[j].target; |
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207 | |
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208 | if(vertices[src]==0) |
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209 | { |
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210 | vertices[src]=j+offset; |
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211 | } |
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212 | edges_array[j].source=vertices[src]; |
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213 | |
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214 | if(vertices[trg]==0) |
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215 | { |
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216 | offset++; |
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217 | vertices[trg]=j+offset; |
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218 | } |
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219 | edges_array[j].target=vertices[trg]; |
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220 | |
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221 | for(z=0; z<MAX_RULE_LENGTH;++z) |
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222 | { |
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223 | if(edges_array[j].rule[z] > 0) |
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224 | { |
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225 | rule.push_back(edges_array[j].rule[z]); |
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226 | } |
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227 | } |
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228 | |
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229 | if(edges_array[j].to_cost > 0) |
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230 | { |
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231 | adjacent_edges[edges_array[j].id].push_back(std::pair<float8, vector<int> > (edges_array[j].to_cost, rule) ); |
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232 | rule.clear(); |
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233 | } |
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234 | |
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235 | if((j < count-1 && edges_array[j].id != edges_array[j+1].id)||(j==count-1)) |
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236 | { |
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237 | graph_add_edge<graph_t, edge_descriptor>(graph, j, |
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238 | edges_array[j].id, edges_array[j].source, |
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239 | edges_array[j].target, edges_array[j].cost, |
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240 | edges_array[j].s_x, edges_array[j].s_y, |
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241 | edges_array[j].t_x, edges_array[j].t_y, adjacent_edges); |
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242 | |
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243 | // if the edge is not directed or if it is directed and has reverse cost |
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244 | if (!directed || (directed && has_reverse_cost)) |
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245 | { |
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246 | float8 cost; |
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247 | |
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248 | if (has_reverse_cost) |
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249 | { |
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250 | cost = edges_array[j].reverse_cost; |
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251 | } |
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252 | else |
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253 | { |
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254 | cost = edges_array[j].cost; |
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255 | } |
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256 | |
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257 | |
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258 | if(adjacent_edges[edges_array[j].id].size() > 0) |
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259 | { |
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260 | adjacent_edges[edges_array[j].id+e_max_id].assign( adjacent_edges[edges_array[j].id].begin(), adjacent_edges[edges_array[j].id].end() ); |
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261 | adjacent_edges.erase(edges_array[j].id); |
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262 | } |
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263 | |
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264 | |
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265 | graph_add_edge<graph_t, edge_descriptor>(graph, j, |
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266 | edges_array[j].id+e_max_id, edges_array[j].target, |
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267 | edges_array[j].source, cost, |
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268 | edges_array[j].s_x, edges_array[j].s_y, |
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269 | edges_array[j].t_x, edges_array[j].t_y, adjacent_edges); |
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270 | } |
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271 | |
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272 | adjacent_edges.clear(); |
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273 | rule_num = 0; |
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274 | } |
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275 | else |
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276 | { |
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277 | rule_num++; |
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278 | } |
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279 | } |
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280 | |
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281 | |
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282 | edge_descriptor source_edge; |
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283 | edge_descriptor target_edge; |
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284 | |
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285 | bool source_found = false, target_found = false; |
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286 | |
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287 | graph_traits<graph_t>::edge_iterator ei, ei_end; |
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288 | |
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289 | for(tie(ei, ei_end) = edges(graph); ei != ei_end; ++ei) |
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290 | { |
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291 | if(graph[*ei].id == source_edge_id) |
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292 | { |
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293 | source_edge = *ei; |
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294 | source_found = true; |
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295 | break; |
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296 | } |
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297 | |
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298 | } |
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299 | |
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300 | if (!source_found) |
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301 | { |
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302 | *err_msg = (char *) "Source edge not found"; |
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303 | return -2; |
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304 | } |
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305 | |
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306 | |
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307 | for(tie(ei, ei_end) = edges(graph); ei != ei_end; ++ei) |
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308 | { |
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309 | if(graph[*ei].id == target_edge_id) |
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310 | { |
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311 | target_edge = *ei; |
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312 | target_found = true; |
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313 | break; |
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314 | } |
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315 | } |
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316 | |
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317 | |
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318 | if (!target_found) |
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319 | { |
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320 | *err_msg = (char *) "Target edge not found"; |
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321 | return -3; |
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322 | } |
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323 | |
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324 | property_map<graph_t, std::size_t Edge::*>::type edge_index = get(&Edge::index, graph); |
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325 | |
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326 | std::map< int, edge_descriptor, std::less<int> > predecessors; |
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327 | |
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328 | property_map<graph_t, float Edge::*>::type rank = get(&Edge::rank, graph); |
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329 | property_map<graph_t, float Edge::*>::type distance = get(&Edge::distance, graph); |
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330 | |
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331 | try |
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332 | { |
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333 | //calling Shooting* search |
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334 | shooting_star_search |
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335 | (graph, source_edge, |
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336 | distance_heuristic<graph_t, float>(graph, target_edge), |
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337 | weight_map(get(&Edge::cost, graph)). |
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338 | weight_map2(get(&Edge::adjacent_edges, graph)). |
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339 | edge_color_map(get(&Edge::color, graph)). |
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340 | visitor(shooting_star_goal_visitor<edge_descriptor>(target_edge, e_max_id)), |
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341 | edge_index, |
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342 | distance, rank, |
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343 | predecessors, e_max_id |
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344 | ); |
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345 | |
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346 | } |
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347 | catch(found_goal<edge_descriptor> &fg) |
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348 | { |
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349 | |
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350 | vector<edge_descriptor> path_vect; |
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351 | int max = MAX_NODES; |
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352 | |
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353 | target_edge = fg.get_target(); |
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354 | |
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355 | path_vect.push_back(target_edge); |
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356 | |
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357 | while (target_edge != source_edge) |
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358 | { |
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359 | |
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360 | if ((target_edge == predecessors[graph[target_edge].id]) && (predecessors[graph[target_edge].id] != source_edge)) |
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361 | { |
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362 | *err_msg = (char *) "No path found"; |
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363 | return -1; |
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364 | |
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365 | } |
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366 | |
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367 | target_edge = predecessors[graph[target_edge].id]; |
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368 | |
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369 | path_vect.push_back(target_edge); |
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370 | |
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371 | // This check was made to be sure that we can |
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372 | // restore the path from the target edge within |
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373 | // MAX_NODE iterations. |
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374 | // Sometimes it doesn't work properly and search exits here |
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375 | // even if the target edge was reached. |
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376 | |
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377 | if (!max--) |
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378 | { |
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379 | *err_msg = (char *) "No path found"; |
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380 | return -1; |
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381 | } |
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382 | } |
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383 | |
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384 | *path = (path_element_t *) malloc(sizeof(path_element_t) * |
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385 | (path_vect.size() + 1)); |
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386 | *path_count = path_vect.size(); |
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387 | |
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388 | for(int i = path_vect.size() - 1, j = 0; i >= 0; i--, j++) |
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389 | { |
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390 | graph_traits < graph_t >::edge_descriptor e; |
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391 | |
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392 | e = path_vect.at(i); |
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393 | |
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394 | if(graph[e].id > e_max_id) |
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395 | { |
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396 | graph[e].id -= e_max_id; |
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397 | } |
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398 | |
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399 | (*path)[j].edge_id = graph[e].id; |
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400 | (*path)[j].cost = graph[e].cost; |
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401 | (*path)[j].vertex_id = source(e, graph); |
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402 | } |
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403 | |
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404 | return EXIT_SUCCESS; |
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405 | } |
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406 | |
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407 | *err_msg = (char *) "Target was not reached"; |
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408 | return 0; |
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409 | |
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410 | } |
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411 | |
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