src/work/marci/max_flow_demo.cc
author alpar
Tue, 07 Sep 2004 10:56:37 +0000
changeset 814 d2d747fe1db3
parent 775 e46a1f0623a0
child 849 cc3867a7d380
permissions -rw-r--r--
Improve docs.
     1 // -*- c++ -*-
     2 
     3 // Use a DIMACS max flow file as stdin.
     4 // max_flow_demo < dimacs_max_flow_file
     5 
     6 
     7 #include <iostream>
     8 #include <fstream>
     9 
    10 #include <sage_graph.h>
    11 #include <hugo/smart_graph.h>
    12 #include <hugo/dimacs.h>
    13 #include <hugo/time_measure.h>
    14 //#include <graph_wrapper.h>
    15 #include <hugo/max_flow.h>
    16 #include <augmenting_flow.h>
    17 //#include <preflow_res.h>
    18 #include <for_each_macros.h>
    19 #include <graph_concept.h>
    20 
    21 using namespace hugo;
    22 
    23 int main(int, char **) {
    24 
    25   typedef SageGraph MutableGraph;
    26 
    27   //typedef FullFeatureGraphConcept Graph;
    28   //typedef SmartGraph Graph;
    29   typedef SageGraph Graph;
    30   typedef Graph::Node Node;
    31   typedef Graph::EdgeIt EdgeIt;
    32 
    33   Graph g;
    34 
    35   Node s, t;
    36   Graph::EdgeMap<int> cap(g);
    37   //readDimacsMaxFlow(std::cin, g, s, t, cap);
    38   readDimacs(std::cin, g, cap, s, t);
    39   Timer ts;
    40   Graph::EdgeMap<int> flow(g); //0 flow
    41   MaxFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    42     max_flow_test(g, s, t, cap, flow);
    43   AugmentingFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    44     augmenting_flow_test(g, s, t, cap, flow);
    45   
    46   Graph::NodeMap<bool> cut(g);
    47 
    48   {
    49     std::cout << "preflow ..." << std::endl;
    50     ts.reset();
    51     max_flow_test.run();
    52     std::cout << "elapsed time: " << ts << std::endl;
    53     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    54     max_flow_test.actMinCut(cut);
    55 
    56     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
    57       if (cut[g.tail(e)] && !cut[g.head(e)] && !flow[e]==cap[e]) 
    58 	std::cout << "Slackness does not hold!" << std::endl;
    59       if (!cut[g.tail(e)] && cut[g.head(e)] && flow[e]>0) 
    60 	std::cout << "Slackness does not hold!" << std::endl;
    61     }
    62   }
    63 
    64   {
    65     std::cout << "preflow ..." << std::endl;
    66     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    67     ts.reset();
    68     max_flow_test.preflow(MaxFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> >::GEN_FLOW);
    69     std::cout << "elapsed time: " << ts << std::endl;
    70     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    71 
    72     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
    73       if (cut[g.tail(e)] && !cut[g.head(e)] && !flow[e]==cap[e]) 
    74 	std::cout << "Slackness does not hold!" << std::endl;
    75       if (!cut[g.tail(e)] && cut[g.head(e)] && flow[e]>0) 
    76 	std::cout << "Slackness does not hold!" << std::endl;
    77     }
    78   }
    79 
    80 //   {
    81 //     std::cout << "wrapped preflow ..." << std::endl;
    82 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    83 //     ts.reset();
    84 //     pre_flow_res.run();
    85 //     std::cout << "elapsed time: " << ts << std::endl;
    86 //     std::cout << "flow value: "<< pre_flow_test.flowValue() << std::endl;
    87 //   }
    88 
    89   {
    90     std::cout << "physical blocking flow augmentation ..." << std::endl;
    91     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    92     ts.reset();
    93     int i=0;
    94     while (augmenting_flow_test.augmentOnBlockingFlow<MutableGraph>()) { ++i; }
    95     std::cout << "elapsed time: " << ts << std::endl;
    96     std::cout << "number of augmentation phases: " << i << std::endl; 
    97     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
    98 
    99     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   100       if (cut[g.tail(e)] && !cut[g.head(e)] && !flow[e]==cap[e]) 
   101 	std::cout << "Slackness does not hold!" << std::endl;
   102       if (!cut[g.tail(e)] && cut[g.head(e)] && flow[e]>0) 
   103 	std::cout << "Slackness does not hold!" << std::endl;
   104     }
   105   }
   106 
   107   {
   108     std::cout << "on-the-fly blocking flow augmentation ..." << std::endl;
   109     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   110     ts.reset();
   111     int i=0;
   112     while (augmenting_flow_test.augmentOnBlockingFlow2()) { ++i; }
   113     std::cout << "elapsed time: " << ts << std::endl;
   114     std::cout << "number of augmentation phases: " << i << std::endl; 
   115     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   116 
   117     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   118       if (cut[g.tail(e)] && !cut[g.head(e)] && !flow[e]==cap[e]) 
   119 	std::cout << "Slackness does not hold!" << std::endl;
   120       if (!cut[g.tail(e)] && cut[g.head(e)] && flow[e]>0) 
   121 	std::cout << "Slackness does not hold!" << std::endl;
   122     }
   123   }
   124 
   125   {
   126     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   127     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   128     ts.reset();
   129     int i=0;
   130     while (augmenting_flow_test.augmentOnShortestPath()) { ++i; }
   131     std::cout << "elapsed time: " << ts << std::endl;
   132     std::cout << "number of augmentation phases: " << i << std::endl; 
   133     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   134 
   135     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   136       if (cut[g.tail(e)] && !cut[g.head(e)] && !flow[e]==cap[e]) 
   137 	std::cout << "Slackness does not hold!" << std::endl;
   138       if (!cut[g.tail(e)] && cut[g.head(e)] && flow[e]>0) 
   139 	std::cout << "Slackness does not hold!" << std::endl;
   140     }
   141   }
   142 
   143   {
   144     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   145     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   146     ts.reset();
   147     int i=0;
   148     while (augmenting_flow_test.augmentOnShortestPath2()) { ++i; }
   149     std::cout << "elapsed time: " << ts << std::endl;
   150     std::cout << "number of augmentation phases: " << i << std::endl; 
   151     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   152 
   153     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   154       if (cut[g.tail(e)] && !cut[g.head(e)] && !flow[e]==cap[e]) 
   155 	std::cout << "Slackness does not hold!" << std::endl;
   156       if (!cut[g.tail(e)] && cut[g.head(e)] && flow[e]>0) 
   157 	std::cout << "Slackness does not hold!" << std::endl;
   158     }
   159   }
   160 
   161   return 0;
   162 }