src/work/jacint/preflow_res_comp.cc
author jacint
Tue, 27 Apr 2004 10:27:34 +0000
changeset 437 9853b743d830
permissions -rw-r--r--
Testing preprocess.
     1 /*
     2 The only difference between preflow.h and preflow_res.h is that the latter
     3 uses the ResGraphWrapper, while the first does not. (Bfs is implemented by
     4 hand in both.) This test program runs Preflow and PreflowRes on the same
     5 graph, tests the result of these implementations and writes the running time
     6 of them.  */
     7 #include <iostream>
     8 
     9 #include <smart_graph.h>
    10 #include <dimacs.h>
    11 #include <preflow.h>
    12 #include <preflow_res.h>
    13 #include <time_measure.h>
    14 
    15 using namespace hugo;
    16 
    17 int main(int, char **) {
    18  
    19   typedef SmartGraph Graph;
    20   
    21   typedef Graph::Node Node;
    22   typedef Graph::EdgeIt EdgeIt;
    23 
    24   Graph G;
    25   Node s, t;
    26   Graph::EdgeMap<int> cap(G);
    27   readDimacsMaxFlow(std::cin, G, s, t, cap);
    28   Timer ts;
    29   
    30   std::cout <<
    31     "\n  In which way are we faster: using ResGraphWrapper or not?"
    32 	    <<std::endl;
    33   std::cout <<
    34     "\n  Running preflow.h on a graph with " << 
    35     G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
    36 	   << std::endl<<std::endl;
    37 
    38 
    39   
    40   Graph::EdgeMap<int> flow(G,0);
    41   Preflow<Graph, int> max_flow_test(G, s, t, cap, flow, 1);
    42   ts.reset();
    43   max_flow_test.run();
    44   std::cout << "Elapsed time NOT using the ResGraphWrapper: " << std::endl 
    45 	    <<ts << std::endl;
    46   
    47   Graph::NodeMap<bool> mincut(G);
    48   max_flow_test.minMinCut(mincut); 
    49   int min_min_cut_value=0;
    50   EdgeIt e;
    51   for(G.first(e); G.valid(e); G.next(e)) {
    52     if (mincut[G.tail(e)] && !mincut[G.head(e)]) min_min_cut_value+=cap[e];
    53   }
    54 
    55   Graph::NodeMap<bool> cut(G);
    56   max_flow_test.minCut(cut); 
    57   int min_cut_value=0;
    58   for(G.first(e); G.valid(e); G.next(e)) {
    59     if (cut[G.tail(e)] && !cut[G.head(e)]) 
    60       min_cut_value+=cap[e];
    61   }
    62 
    63   Graph::NodeMap<bool> maxcut(G);
    64   max_flow_test.maxMinCut(maxcut); 
    65   int max_min_cut_value=0;
    66   for(G.first(e); G.valid(e); G.next(e)) {
    67     if (maxcut[G.tail(e)] && !maxcut[G.head(e)]) 
    68       max_min_cut_value+=cap[e];
    69       }
    70 
    71   std::cout << "\n Checking the result: " <<std::endl;  
    72   std::cout << "Flow value: "<< max_flow_test.flowValue() << std::endl;
    73   std::cout << "Min cut value: "<< min_cut_value << std::endl;
    74   std::cout << "Min min cut value: "<< min_min_cut_value << std::endl;
    75   std::cout << "Max min cut value: "<< max_min_cut_value << 
    76     std::endl;
    77 
    78   if ( max_flow_test.flowValue() == min_cut_value &&
    79        min_cut_value == min_min_cut_value &&
    80        min_min_cut_value == max_min_cut_value )
    81     std::cout << "They are equal! " <<std::endl<< std::endl<<"\n";  
    82   
    83   Graph::EdgeMap<int> flow2(G,0);
    84   PreflowRes<Graph, int> max_flow_test2(G, s, t, cap, flow2, 1);
    85   ts.reset();
    86   max_flow_test2.run();
    87   std::cout << "Elapsed time using the ResGraphWrapper: " << std::endl 
    88 	    << ts << std::endl;
    89   
    90   Graph::NodeMap<bool> mincut2(G);
    91   max_flow_test2.minMinCut(mincut2); 
    92   int min_min_cut_value2=0;
    93     for(G.first(e); G.valid(e); G.next(e)) {
    94     if (mincut2[G.tail(e)] && !mincut2[G.head(e)]) min_min_cut_value2+=cap[e];
    95   }
    96 
    97   Graph::NodeMap<bool> cut2(G);
    98   max_flow_test2.minCut(cut2); 
    99   int min_cut_value2=0;
   100   for(G.first(e); G.valid(e); G.next(e)) {
   101     if (cut2[G.tail(e)] && !cut2[G.head(e)]) 
   102       min_cut_value2+=cap[e];
   103   }
   104 
   105   Graph::NodeMap<bool> maxcut2(G);
   106   max_flow_test2.maxMinCut(maxcut2); 
   107   int max_min_cut_value2=0;
   108   for(G.first(e); G.valid(e); G.next(e)) {
   109     if (maxcut2[G.tail(e)] && !maxcut2[G.head(e)]) 
   110       max_min_cut_value2+=cap[e];
   111       }
   112   
   113   std::cout << "\n Checking the result: " <<std::endl;  
   114   std::cout << "Flow value: "<< max_flow_test2.flowValue() << std::endl;
   115   std::cout << "Min cut value: "<< min_cut_value2 << std::endl;
   116   std::cout << "Min min cut value: "<< min_min_cut_value2 << std::endl;
   117   std::cout << "Max min cut value: "<< max_min_cut_value2 << 
   118     std::endl;  
   119   if ( max_flow_test.flowValue() == min_cut_value &&
   120        min_cut_value == min_min_cut_value &&
   121        min_min_cut_value == max_min_cut_value )
   122     std::cout << "They are equal! " <<std::endl<<"/n";  
   123   
   124   return 0;
   125 }