demo/min_route.cc
author deba
Wed, 23 Nov 2005 16:08:02 +0000
changeset 1830 ffd6d50fb155
parent 1636 260ac104190f
child 1875 98698b69a902
permissions -rw-r--r--
Document improvments
     1 /* -*- C++ -*-
     2  * demo/min_route.cc - Part of LEMON, a generic C++ optimization library
     3  *
     4  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     5  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     6  *
     7  * Permission to use, modify and distribute this software is granted
     8  * provided that this copyright notice appears in all copies. For
     9  * precise terms see the accompanying LICENSE file.
    10  *
    11  * This software is provided "AS IS" with no warranty of any kind,
    12  * express or implied, and with no claim as to its suitability for any
    13  * purpose.
    14  *
    15  */
    16 
    17 #include <iostream>
    18 #include <fstream>
    19 
    20 #include <lemon/smart_graph.h>
    21 #include <lemon/dijkstra.h>
    22 #include <lemon/maps.h>
    23 #include <lemon/xy.h>
    24 #include <lemon/graph_reader.h>
    25 
    26 #include <lemon/time_measure.h>
    27 
    28 #include <cmath>
    29 
    30 /// \ingroup demos
    31 /// \file
    32 /// \brief Minimal route on a plan graph with eucledian distances.
    33 ///
    34 /// Minimal route on a plan graph with eucledian distances.
    35 ///
    36 /// \include min_route.cc
    37 
    38 
    39 using namespace lemon;
    40 
    41 template <typename CoordMap>
    42 class PotentialMap {
    43 public:
    44   typedef double Value;
    45   typedef typename CoordMap::Key Key;
    46 
    47   PotentialMap(const CoordMap& _coord, const xy<double>& _target)
    48     : coord(_coord), target(_target) {}
    49 
    50   double operator[](const Key& node) const {
    51     return std::sqrt((coord[node].x - target.x) * (coord[node].x - target.x) + 
    52 		     (coord[node].y - target.y) * (coord[node].y - target.y));
    53   }
    54 private:
    55   const CoordMap& coord;
    56   xy<double> target;
    57 };
    58 
    59 template <typename Graph, typename LengthMap, typename PotentialMap>
    60 class ReducedLengthMap {
    61 public:
    62   typedef double Value;
    63   typedef typename LengthMap::Key Key;
    64 
    65   ReducedLengthMap(const Graph& _graph, const LengthMap& _length, 
    66 		   const PotentialMap& _pot) 
    67     : graph(_graph), length(_length), pot(_pot) {}
    68 
    69   Value operator[](const Key& edge) const {
    70     return length[edge] - (pot[graph.source(edge)] - pot[graph.target(edge)]);
    71   }
    72 
    73 private:
    74   const Graph& graph;
    75   const LengthMap& length;
    76   const PotentialMap& pot;
    77 };
    78 
    79 int main() {
    80   typedef SmartGraph Graph;
    81 
    82   typedef Graph::Edge Edge;
    83   typedef Graph::Node Node;
    84   typedef Graph::EdgeIt EdgeIt;
    85   typedef Graph::NodeIt NodeIt;
    86   typedef Graph::EdgeMap<double> LengthMap;
    87   typedef Graph::NodeMap<xy<double> > CoordMap;
    88 
    89   SmartGraph graph;
    90 
    91   std::ifstream is("route.lgf");
    92   GraphReader<Graph> reader(is, graph);
    93   
    94   CoordMap coord(graph);
    95   XMap<CoordMap> xcoord = xMap(coord);
    96   reader.readNodeMap("coordinates_x", xcoord);
    97   YMap<CoordMap> ycoord = yMap(coord);
    98   reader.readNodeMap("coordinates_y", ycoord);
    99 
   100   LengthMap length(graph);
   101   reader.readEdgeMap("length", length);
   102 
   103   Node source, target;
   104   reader.readNode("source", source);
   105   reader.readNode("target", target);
   106 
   107   reader.run();
   108 
   109   {
   110     Timer timer;
   111     Dijkstra<Graph, LengthMap> dijkstra(graph, length);
   112     dijkstra.init();
   113     dijkstra.addSource(source);
   114     dijkstra.start(target);
   115 
   116     std::cout << dijkstra.dist(target) << std::endl;
   117     std::cout << timer << std::endl;
   118   }
   119   {
   120     Timer timer;
   121     typedef PotentialMap<CoordMap> Potential;
   122     Potential potential(coord, coord[target]);
   123 
   124     typedef ReducedLengthMap<Graph, LengthMap, Potential> ReducedLength;
   125     ReducedLength reduced(graph, length, potential);
   126 
   127     Dijkstra<Graph, ReducedLength> dijkstra(graph, reduced);
   128 
   129     dijkstra.init();
   130     dijkstra.addSource(source);
   131     dijkstra.start(target);
   132   
   133     std::cout << dijkstra.dist(target) + potential[source] << std::endl;
   134     std::cout << timer << std::endl;
   135   }
   136 
   137   return 0;
   138 }