src/work/marci/lp/max_flow_by_lp.cc
author marci
Wed, 16 Feb 2005 21:40:16 +0000
changeset 1152 1765ff9fefa1
parent 1025 3b1ad8bc21da
permissions -rw-r--r--
small changes
     1 // -*- c++ -*-
     2 #include <iostream>
     3 #include <fstream>
     4 
     5 #include <lemon/smart_graph.h>
     6 #include <lemon/list_graph.h>
     7 #include <lemon/dimacs.h>
     8 #include <lemon/time_measure.h>
     9 //#include <graph_wrapper.h>
    10 #include <lemon/preflow.h>
    11 #include <augmenting_flow.h>
    12 //#include <preflow_res.h>
    13 //#include <lp_solver_wrapper_2.h>
    14 #include <min_cost_gen_flow.h>
    15 
    16 // Use a DIMACS max flow file as stdin.
    17 // max_flow_demo < dimacs_max_flow_file
    18 
    19 using namespace lemon;
    20 
    21 int main(int, char **) {
    22 
    23   typedef ListGraph MutableGraph;
    24   typedef ListGraph Graph;
    25   typedef Graph::Node Node;
    26   typedef Graph::Edge Edge;
    27   typedef Graph::EdgeIt EdgeIt;
    28 
    29   Graph g;
    30 
    31   Node s, t;
    32   Graph::EdgeMap<int> cap(g);
    33   //readDimacsMaxFlow(std::cin, g, s, t, cap);
    34   readDimacs(std::cin, g, cap, s, t);
    35   Timer ts;
    36   Graph::EdgeMap<int> flow(g); //0 flow
    37   Preflow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    38     max_flow_test(g, s, t, cap, flow);
    39   AugmentingFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    40     augmenting_flow_test(g, s, t, cap, flow);
    41   
    42   Graph::NodeMap<bool> cut(g);
    43 
    44   {
    45     std::cout << "preflow ..." << std::endl;
    46     ts.reset();
    47     max_flow_test.run();
    48     std::cout << "elapsed time: " << ts << std::endl;
    49     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    50     max_flow_test.minCut(cut);
    51 
    52     for (EdgeIt e(g); e!=INVALID; ++e) {
    53       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
    54 	std::cout << "Slackness does not hold!" << std::endl;
    55       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
    56 	std::cout << "Slackness does not hold!" << std::endl;
    57     }
    58   }
    59 
    60 //   {
    61 //     std::cout << "preflow ..." << std::endl;
    62 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    63 //     ts.reset();
    64 //     max_flow_test.preflow(Preflow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> >::GEN_FLOW);
    65 //     std::cout << "elapsed time: " << ts << std::endl;
    66 //     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    67 
    68 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
    69 //       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
    70 // 	std::cout << "Slackness does not hold!" << std::endl;
    71 //       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
    72 // 	std::cout << "Slackness does not hold!" << std::endl;
    73 //     }
    74 //   }
    75 
    76 //   {
    77 //     std::cout << "wrapped preflow ..." << std::endl;
    78 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    79 //     ts.reset();
    80 //     pre_flow_res.run();
    81 //     std::cout << "elapsed time: " << ts << std::endl;
    82 //     std::cout << "flow value: "<< pre_flow_test.flowValue() << std::endl;
    83 //   }
    84 
    85   {
    86     std::cout << "physical blocking flow augmentation ..." << std::endl;
    87     for (EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
    88     ts.reset();
    89     int i=0;
    90     while (augmenting_flow_test.augmentOnBlockingFlow<MutableGraph>()) { ++i; }
    91     std::cout << "elapsed time: " << ts << std::endl;
    92     std::cout << "number of augmentation phases: " << i << std::endl; 
    93     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
    94 
    95     for (EdgeIt e(g); e!=INVALID; ++e) {
    96       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
    97 	std::cout << "Slackness does not hold!" << std::endl;
    98       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
    99 	std::cout << "Slackness does not hold!" << std::endl;
   100     }
   101   }
   102 
   103 //   {
   104 //     std::cout << "faster physical blocking flow augmentation ..." << std::endl;
   105 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   106 //     ts.reset();
   107 //     int i=0;
   108 //     while (max_flow_test.augmentOnBlockingFlow1<MutableGraph>()) { ++i; }
   109 //     std::cout << "elapsed time: " << ts << std::endl;
   110 //     std::cout << "number of augmentation phases: " << i << std::endl; 
   111 //     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
   112 //   }
   113 
   114   {
   115     std::cout << "on-the-fly blocking flow augmentation ..." << std::endl;
   116     for (EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
   117     ts.reset();
   118     int i=0;
   119     while (augmenting_flow_test.augmentOnBlockingFlow2()) { ++i; }
   120     std::cout << "elapsed time: " << ts << std::endl;
   121     std::cout << "number of augmentation phases: " << i << std::endl; 
   122     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   123 
   124     for (EdgeIt e(g); e!=INVALID; ++e) {
   125       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   126 	std::cout << "Slackness does not hold!" << std::endl;
   127       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   128 	std::cout << "Slackness does not hold!" << std::endl;
   129     }
   130   }
   131 
   132 //   {
   133 //     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   134 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   135 //     ts.reset();
   136 //     int i=0;
   137 //     while (augmenting_flow_test.augmentOnShortestPath()) { ++i; }
   138 //     std::cout << "elapsed time: " << ts << std::endl;
   139 //     std::cout << "number of augmentation phases: " << i << std::endl; 
   140 //     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   141 
   142 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   143 //       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   144 // 	std::cout << "Slackness does not hold!" << std::endl;
   145 //       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   146 // 	std::cout << "Slackness does not hold!" << std::endl;
   147 //     }
   148 //   }
   149 
   150 //   {
   151 //     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   152 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   153 //     ts.reset();
   154 //     int i=0;
   155 //     while (augmenting_flow_test.augmentOnShortestPath2()) { ++i; }
   156 //     std::cout << "elapsed time: " << ts << std::endl;
   157 //     std::cout << "number of augmentation phases: " << i << std::endl; 
   158 //     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   159 
   160 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   161 //       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   162 // 	std::cout << "Slackness does not hold!" << std::endl;
   163 //       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   164 // 	std::cout << "Slackness does not hold!" << std::endl;
   165 //     }
   166 //   }
   167 
   168   ts.reset();
   169 
   170   Edge e=g.addEdge(t, s);
   171   Graph::EdgeMap<int> cost(g, 0);
   172   cost.set(e, -1);
   173   cap.set(e, 10000);
   174   typedef ConstMap<Node, int> Excess;
   175   Excess excess(0);
   176   typedef ConstMap<Edge, int> LCap;
   177   LCap lcap(0);
   178 
   179   MinCostGenFlow<Graph, int, Excess, LCap> 
   180     min_cost(g, excess, lcap, cap, flow, cost); 
   181   min_cost.feasible();
   182   min_cost.runByLP();
   183 
   184   std::cout << "elapsed time: " << ts << std::endl;
   185   std::cout << "flow value: "<< flow[e] << std::endl;
   186 }