1 | /* -*- C++ -*- |
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2 | * |
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3 | * This file is a part of LEMON, a generic C++ optimization library |
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4 | * |
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5 | * Copyright (C) 2003-2006 |
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6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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8 | * |
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9 | * Permission to use, modify and distribute this software is granted |
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10 | * provided that this copyright notice appears in all copies. For |
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11 | * precise terms see the accompanying LICENSE file. |
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12 | * |
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13 | * This software is provided "AS IS" with no warranty of any kind, |
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14 | * express or implied, and with no claim as to its suitability for any |
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15 | * purpose. |
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16 | * |
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17 | */ |
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18 | |
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19 | ///\ingroup demos |
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20 | ///\file |
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21 | ///\brief Demonstrating the usage of LEMON's Dijkstra algorithm |
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22 | /// |
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23 | /// Dijkstra's algorithm computes shortest paths between two nodes in |
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24 | /// a graph with edge lengths. Here we only show some of the |
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25 | /// facilities supplied by our implementation: for the detailed |
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26 | /// documentation of the LEMON Dijkstra class read \ref lemon::Dijkstra "this". |
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27 | /// |
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28 | /// \include dijkstra_demo.cc |
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29 | |
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30 | #include <iostream> |
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31 | #include <lemon/list_graph.h> |
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32 | #include <lemon/csp.h> |
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33 | #include <lemon/random.h> |
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34 | |
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35 | |
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36 | using namespace lemon; |
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37 | |
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38 | |
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39 | int main (int, char*[]) |
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40 | { |
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41 | |
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42 | typedef ListGraph Graph; |
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43 | typedef Graph::Node Node; |
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44 | typedef Graph::Edge Edge; |
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45 | typedef Graph::EdgeIt EdgeIt; |
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46 | typedef Graph::EdgeMap<double> LengthMap; |
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47 | |
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48 | Graph g; |
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49 | |
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50 | const int N=100; |
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51 | const int M=20000; |
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52 | std::vector<Node> nodes; |
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53 | std::vector<Edge> edges; |
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54 | |
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55 | for(int i=0;i<N;i++) nodes.push_back(g.addNode()); |
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56 | |
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57 | for(int i=0;i<M;i++) |
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58 | edges.push_back(g.addEdge(nodes[rnd[N]],nodes[rnd[N]])); |
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59 | |
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60 | LengthMap cost(g); |
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61 | LengthMap delay(g); |
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62 | for(EdgeIt e(g);e!=INVALID;++e) |
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63 | { |
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64 | cost[e]=0.01+rnd(.99); |
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65 | delay[e]=0.01+rnd(.99); |
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66 | } |
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67 | |
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68 | ConstrainedShortestPath<Graph,LengthMap,LengthMap> csp(g,cost,delay); |
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69 | for(double d=0;d<2;d+=.01) |
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70 | { |
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71 | double lo_bo; |
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72 | std::cout << d << ": "; |
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73 | SimplePath<Graph> r = csp.larac(nodes[0],nodes[1],d,lo_bo); |
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74 | if(r.empty()) std::cout << "INFEASIBLE\n"; |
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75 | else std::cout << "delay: " << csp.delay(r) |
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76 | << " cost: " << csp.cost(r) |
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77 | << " (lb: " << lo_bo |
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78 | << " gap: " << csp.cost(r)-lo_bo |
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79 | << " , " << (csp.cost(r)-lo_bo)/csp.cost(r)*100 |
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80 | << "%)" << std::endl; |
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81 | } |
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82 | |
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83 | return 0; |
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84 | } |
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