src/work/marci/max_flow_demo.cc
author klao
Wed, 09 Mar 2005 14:23:36 +0000
changeset 1209 dc9fdf77007f
parent 921 818510fa3d99
permissions -rw-r--r--
Fix a bug noticed by deba.
     1 // -*- c++ -*-
     2 
     3 // Use a DIMACS max flow file as stdin.
     4 // max_flow_demo < dimacs_max_flow_file
     5 
     6 #include <iostream>
     7 #include <fstream>
     8 
     9 #include <lemon/smart_graph.h>
    10 #include <lemon/list_graph.h>
    11 #include <lemon/dimacs.h>
    12 #include <lemon/time_measure.h>
    13 #include <lemon/preflow.h>
    14 #include <augmenting_flow.h>
    15 #include <graph_concept.h>
    16 
    17 using namespace lemon;
    18 
    19 int main(int, char **) {
    20 
    21   typedef ListGraph MutableGraph;
    22   typedef SmartGraph Graph;
    23   typedef Graph::Node Node;
    24   typedef Graph::EdgeIt EdgeIt;
    25 
    26   Graph g;
    27 
    28   Node s, t;
    29   Graph::EdgeMap<int> cap(g);
    30   //readDimacsMaxFlow(std::cin, g, s, t, cap);
    31   readDimacs(std::cin, g, cap, s, t);
    32   Timer ts;
    33   Graph::EdgeMap<int> flow(g); //0 flow
    34   Preflow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    35     max_flow_test(g, s, t, cap, flow);
    36   AugmentingFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    37     augmenting_flow_test(g, s, t, cap, flow);
    38   
    39   Graph::NodeMap<bool> cut(g);
    40 
    41   {
    42     std::cout << "preflow ..." << std::endl;
    43     ts.reset();
    44     max_flow_test.run();
    45     std::cout << "elapsed time: " << ts << std::endl;
    46     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    47     max_flow_test.minCut(cut);
    48 
    49     for(Graph::EdgeIt e(g); e!=INVALID; ++e) {
    50       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
    51 	std::cout << "Slackness does not hold!" << std::endl;
    52       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
    53 	std::cout << "Slackness does not hold!" << std::endl;
    54     }
    55   }
    56 
    57   {
    58     std::cout << "preflow ..." << std::endl;
    59     for(Graph::EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
    60     ts.reset();
    61     max_flow_test.run(Preflow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> >::GEN_FLOW);
    62     std::cout << "elapsed time: " << ts << std::endl;
    63     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    64 
    65     for(Graph::EdgeIt e(g); e!=INVALID; ++e) {
    66       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
    67 	std::cout << "Slackness does not hold!" << std::endl;
    68       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
    69 	std::cout << "Slackness does not hold!" << std::endl;
    70     }
    71   }
    72 
    73 //   {
    74 //     std::cout << "wrapped preflow ..." << std::endl;
    75 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    76 //     ts.reset();
    77 //     pre_flow_res.run();
    78 //     std::cout << "elapsed time: " << ts << std::endl;
    79 //     std::cout << "flow value: "<< pre_flow_test.flowValue() << std::endl;
    80 //   }
    81 
    82   {
    83     std::cout << "physical blocking flow augmentation ..." << std::endl;
    84     for(Graph::EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
    85     ts.reset();
    86     int i=0;
    87     while (augmenting_flow_test.augmentOnBlockingFlow<MutableGraph>()) { ++i; }
    88     std::cout << "elapsed time: " << ts << std::endl;
    89     std::cout << "number of augmentation phases: " << i << std::endl; 
    90     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
    91 
    92     for(Graph::EdgeIt e(g); e!=INVALID; ++e) {
    93       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
    94 	std::cout << "Slackness does not hold!" << std::endl;
    95       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
    96 	std::cout << "Slackness does not hold!" << std::endl;
    97     }
    98   }
    99 
   100   {
   101     std::cout << "on-the-fly blocking flow augmentation ..." << std::endl;
   102     for(Graph::EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
   103     ts.reset();
   104     int i=0;
   105     while (augmenting_flow_test.augmentOnBlockingFlow2()) { ++i; }
   106     std::cout << "elapsed time: " << ts << std::endl;
   107     std::cout << "number of augmentation phases: " << i << std::endl; 
   108     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   109 
   110     for(Graph::EdgeIt e(g); e!=INVALID; ++e) {
   111       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   112 	std::cout << "Slackness does not hold!" << std::endl;
   113       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   114 	std::cout << "Slackness does not hold!" << std::endl;
   115     }
   116   }
   117 
   118   {
   119     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   120     for(Graph::EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
   121     ts.reset();
   122     int i=0;
   123     while (augmenting_flow_test.augmentOnShortestPath()) { ++i; }
   124     std::cout << "elapsed time: " << ts << std::endl;
   125     std::cout << "number of augmentation phases: " << i << std::endl; 
   126     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   127 
   128     for(Graph::EdgeIt e(g); e!=INVALID; ++e) {
   129       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   130 	std::cout << "Slackness does not hold!" << std::endl;
   131       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   132 	std::cout << "Slackness does not hold!" << std::endl;
   133     }
   134   }
   135 
   136   {
   137     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   138     for(Graph::EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
   139     ts.reset();
   140     int i=0;
   141     while (augmenting_flow_test.augmentOnShortestPath2()) { ++i; }
   142     std::cout << "elapsed time: " << ts << std::endl;
   143     std::cout << "number of augmentation phases: " << i << std::endl; 
   144     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   145 
   146     for(Graph::EdgeIt e(g); e!=INVALID; ++e) {
   147       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   148 	std::cout << "Slackness does not hold!" << std::endl;
   149       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   150 	std::cout << "Slackness does not hold!" << std::endl;
   151     }
   152   }
   153 
   154   return 0;
   155 }