src/work/jacint/preflow.cc
changeset 451 6b36be4cffa4
child 470 b64956c701c9
equal deleted inserted replaced
-1:000000000000 7:bfc2962b9a13
       
     1 #include <iostream>
       
     2 
       
     3 #include <smart_graph.h>
       
     4 #include <dimacs.h>
       
     5 #include <preflow.h>
       
     6 #include <time_measure.h>
       
     7 
       
     8 using namespace hugo;
       
     9 
       
    10 int main(int, char **) {
       
    11  
       
    12   typedef SmartGraph Graph;
       
    13   
       
    14   typedef Graph::Node Node;
       
    15   typedef Graph::EdgeIt EdgeIt;
       
    16 
       
    17   Graph G;
       
    18   Node s, t;
       
    19   Graph::EdgeMap<int> cap(G);
       
    20   readDimacsMaxFlow(std::cin, G, s, t, cap);
       
    21   Timer ts;
       
    22   
       
    23   std::cout <<
       
    24     "\n  Testing preflow.h on a graph with " << 
       
    25     G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
       
    26 	   << std::endl;
       
    27 
       
    28 
       
    29   Graph::EdgeMap<int> flow(G,0);
       
    30   Preflow<Graph, int> preflow_test(G, s, t, cap, flow);
       
    31   std::cout << "\nCalling run() (flow must be constant zero)..."<<std::endl;
       
    32   ts.reset();
       
    33   preflow_test.run();
       
    34   std::cout << "Elapsed time: " << ts << std::endl;
       
    35 
       
    36   Graph::NodeMap<bool> mincut(G);
       
    37   preflow_test.minMinCut(mincut); 
       
    38   int min_min_cut_value=0;
       
    39   Graph::NodeMap<bool> cut(G);
       
    40   preflow_test.minCut(cut); 
       
    41   int min_cut_value=0;
       
    42   Graph::NodeMap<bool> maxcut(G);
       
    43   preflow_test.maxMinCut(maxcut); 
       
    44   int max_min_cut_value=0;
       
    45   EdgeIt e;
       
    46   for(G.first(e); G.valid(e); G.next(e)) {
       
    47     int c=cap[e];
       
    48     if (mincut[G.tail(e)] && !mincut[G.head(e)]) min_min_cut_value+=c;
       
    49     if (cut[G.tail(e)] && !cut[G.head(e)]) min_cut_value+=c; 
       
    50     if (maxcut[G.tail(e)] && !maxcut[G.head(e)]) max_min_cut_value+=c;
       
    51   }
       
    52 
       
    53   std::cout << "\nChecking the result: " <<std::endl;  
       
    54   std::cout << "Flow value: "<< preflow_test.flowValue() << std::endl;
       
    55   std::cout << "Min cut value: "<< min_cut_value << std::endl;
       
    56   std::cout << "Min min cut value: "<< min_min_cut_value << std::endl;
       
    57   std::cout << "Max min cut value: "<< max_min_cut_value << 
       
    58     std::endl;
       
    59 
       
    60   if ( preflow_test.flowValue() == min_cut_value &&
       
    61        min_cut_value == min_min_cut_value &&
       
    62        min_min_cut_value == max_min_cut_value )
       
    63     std::cout << "They are equal. " <<std::endl;  
       
    64 
       
    65 
       
    66 
       
    67 
       
    68 
       
    69   Preflow<Graph, int> preflow_test2(G, s, t, cap, flow);
       
    70   std::cout << "\n\nCalling preflow(GEN_FLOW) with the given maximum flow..."<<std::endl;
       
    71   ts.reset();
       
    72   preflow_test2.preflow(preflow_test2.GEN_FLOW);
       
    73   std::cout << "Elapsed time: " << ts << std::endl;
       
    74 
       
    75   Graph::NodeMap<bool> mincut2(G);
       
    76   preflow_test.minMinCut(mincut2); 
       
    77   int min_min_cut2_value=0;
       
    78   Graph::NodeMap<bool> cut2(G);
       
    79   preflow_test.minCut(cut2); 
       
    80   int min_cut2_value=0;
       
    81   Graph::NodeMap<bool> maxcut2(G);
       
    82   preflow_test.maxMinCut(maxcut2); 
       
    83   int max_min_cut2_value=0;
       
    84   for(G.first(e); G.valid(e); G.next(e)) {
       
    85     int c=cap[e];
       
    86     if (mincut2[G.tail(e)] && !mincut2[G.head(e)]) min_min_cut2_value+=c;
       
    87     if (cut2[G.tail(e)] && !cut2[G.head(e)]) min_cut2_value+=c; 
       
    88     if (maxcut2[G.tail(e)] && !maxcut2[G.head(e)]) max_min_cut2_value+=c;
       
    89   }
       
    90 
       
    91   std::cout << "\nThe given flow value is "
       
    92 	    << preflow_test2.flowValue();
       
    93 
       
    94   if ( preflow_test2.flowValue() == min_cut2_value &&
       
    95        min_cut2_value == min_min_cut2_value &&
       
    96        min_min_cut2_value == max_min_cut2_value )
       
    97     std::cout <<", which is equal to all three min cut values." 
       
    98 	      <<std::endl;  
       
    99 
       
   100 
       
   101 
       
   102 
       
   103 
       
   104   Graph::EdgeMap<int> flow3(G,0);
       
   105   Preflow<Graph, int> preflow_test3(G, s, t, cap, flow3);
       
   106   std::cout << "\n\nCalling preflowPhase0(PREFLOW) on the constant zero flow..."<<std::endl;
       
   107   ts.reset();
       
   108   preflow_test3.preflowPhase0(preflow_test3.PREFLOW);
       
   109   std::cout << "Elapsed time: " << ts << std::endl;
       
   110   Graph::NodeMap<bool> actcut3(G);
       
   111   std::cout << "\nCalling actMinCut()..."<<std::endl;
       
   112   preflow_test3.actMinCut(actcut3); 
       
   113   std::cout << "Calling preflowPhase1() on the given flow..."<<std::endl;
       
   114   ts.reset();
       
   115   preflow_test3.preflowPhase1();
       
   116   std::cout << "Elapsed time: " << ts << std::endl;
       
   117   
       
   118   int act_min_cut3_value=0;
       
   119   
       
   120   Graph::NodeMap<bool> mincut3(G);
       
   121   preflow_test.minMinCut(mincut3); 
       
   122   int min_min_cut3_value=0;
       
   123   
       
   124   Graph::NodeMap<bool> cut3(G);
       
   125   preflow_test.minCut(cut3); 
       
   126   int min_cut3_value=0;
       
   127   
       
   128   Graph::NodeMap<bool> maxcut3(G);
       
   129   preflow_test.maxMinCut(maxcut3); 
       
   130   int max_min_cut3_value=0;
       
   131   
       
   132   for(G.first(e); G.valid(e); G.next(e)) {
       
   133     int c=cap[e];
       
   134     if (mincut3[G.tail(e)] && !mincut3[G.head(e)]) min_min_cut3_value+=c;
       
   135     if (cut3[G.tail(e)] && !cut3[G.head(e)]) min_cut3_value+=c; 
       
   136     if (maxcut3[G.tail(e)] && !maxcut3[G.head(e)]) max_min_cut3_value+=c;
       
   137     if (actcut3[G.tail(e)] && !actcut3[G.head(e)]) act_min_cut3_value+=c;
       
   138   }
       
   139 
       
   140  std::cout << "\nThe min cut value given by actMinCut() after phase 0 is "<<
       
   141    act_min_cut3_value;
       
   142 
       
   143   if ( preflow_test3.flowValue() == min_cut3_value &&
       
   144        min_cut3_value == min_min_cut3_value &&
       
   145        min_min_cut3_value == max_min_cut3_value &&
       
   146        max_min_cut3_value == act_min_cut3_value ) {
       
   147     std::cout << 
       
   148       ", which is equal to the given flow value and to all three min cut values after phase 1." 
       
   149 	      <<std::endl;  
       
   150   }
       
   151 
       
   152 
       
   153 
       
   154 
       
   155 
       
   156   Graph::EdgeMap<int> flow4(G,0);
       
   157   Preflow<Graph, int> preflow_test4(G, s, t, cap, flow4);
       
   158   std::cout << 
       
   159     "\n\nCalling preflow(PREFLOW) with the constant 0 flow, the result is f..."
       
   160 	    <<std::endl;
       
   161   preflow_test4.preflow(preflow_test4.PREFLOW);
       
   162 
       
   163   std::cout << "Swapping the source and the target, "<<std::endl;
       
   164   std::cout << "by calling resetSource(t) and resetTarget(s)..."
       
   165 	    <<std::endl;
       
   166   preflow_test4.resetSource(t);
       
   167   preflow_test4.resetTarget(s);
       
   168 
       
   169   std::cout << 
       
   170     "Calling preflow(PREFLOW) to find a maximum t-s flow starting with flow f..."
       
   171 	    <<std::endl;
       
   172   preflow_test4.preflow(preflow_test4.PREFLOW);
       
   173 
       
   174   Graph::NodeMap<bool> mincut4(G);
       
   175   preflow_test4.minMinCut(mincut4); 
       
   176   int min_min_cut4_value=0;
       
   177   Graph::NodeMap<bool> cut4(G);
       
   178   preflow_test4.minCut(cut4); 
       
   179   int min_cut4_value=0;
       
   180   Graph::NodeMap<bool> maxcut4(G);
       
   181   preflow_test4.maxMinCut(maxcut4); 
       
   182   int max_min_cut4_value=0;
       
   183   for(G.first(e); G.valid(e); G.next(e)) {
       
   184     int c=cap[e];
       
   185     if (mincut4[G.tail(e)] && !mincut4[G.head(e)]) min_min_cut4_value+=c;
       
   186     if (cut4[G.tail(e)] && !cut4[G.head(e)]) min_cut4_value+=c; 
       
   187     if (maxcut4[G.tail(e)] && !maxcut4[G.head(e)]) max_min_cut4_value+=c;
       
   188   }
       
   189 
       
   190   std::cout << "\nThe given flow value is "
       
   191 	    << preflow_test4.flowValue();
       
   192   
       
   193   if ( preflow_test4.flowValue() == min_cut4_value &&
       
   194        min_cut4_value == min_min_cut4_value &&
       
   195        min_min_cut4_value == max_min_cut4_value )
       
   196     std::cout <<", which is equal to all three min cut values." 
       
   197 	      <<std::endl;  
       
   198 
       
   199 
       
   200 
       
   201 
       
   202   Graph::EdgeMap<int> flow5(G,0);
       
   203   std::cout << "Resetting the stored flow to constant zero, by calling resetFlow..."
       
   204 	    <<std::endl;
       
   205   preflow_test4.resetFlow(flow5);
       
   206   std::cout << 
       
   207     "Calling preflow(GEN_FLOW) to find a maximum t-s flow "<<std::endl;
       
   208   std::cout << 
       
   209     "starting with this constant zero flow..." <<std::endl;
       
   210   preflow_test4.preflow(preflow_test4.GEN_FLOW);
       
   211 
       
   212   Graph::NodeMap<bool> mincut5(G);
       
   213   preflow_test4.minMinCut(mincut5); 
       
   214   int min_min_cut5_value=0;
       
   215   Graph::NodeMap<bool> cut5(G);
       
   216   preflow_test4.minCut(cut5); 
       
   217   int min_cut5_value=0;
       
   218   Graph::NodeMap<bool> maxcut5(G);
       
   219   preflow_test4.maxMinCut(maxcut5); 
       
   220   int max_min_cut5_value=0;
       
   221   for(G.first(e); G.valid(e); G.next(e)) {
       
   222     int c=cap[e];
       
   223     if (mincut5[G.tail(e)] && !mincut5[G.head(e)]) min_min_cut5_value+=c;
       
   224     if (cut5[G.tail(e)] && !cut5[G.head(e)]) min_cut5_value+=c; 
       
   225     if (maxcut5[G.tail(e)] && !maxcut5[G.head(e)]) max_min_cut5_value+=c;
       
   226   }
       
   227 
       
   228   std::cout << "\nThe given flow value is "
       
   229 	    << preflow_test4.flowValue();
       
   230   
       
   231   if ( preflow_test4.flowValue() == min_cut5_value &&
       
   232        min_cut5_value == min_min_cut5_value &&
       
   233        min_min_cut5_value == max_min_cut5_value )
       
   234     std::cout <<", which is equal to all three min cut values." 
       
   235 	      <<std::endl<<std::endl;  
       
   236 
       
   237 
       
   238   return 0;
       
   239 }