src/work/jacint/preflow.cc
changeset 1365 c280de819a73
parent 921 818510fa3d99
equal deleted inserted replaced
10:89a484ec3acf -1:000000000000
     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 lemon;
       
     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   bool error=false;
       
    23   
       
    24   std::cout <<
       
    25     "\n  Testing preflow.h on a graph with " << 
       
    26     G.nodeNum() << " nodes and " << G.edgeNum() << " edges..."
       
    27 	   << std::endl;
       
    28 
       
    29 
       
    30   Graph::EdgeMap<int> flow(G,0);
       
    31   Preflow<Graph, int> preflow_test(G, s, t, cap, flow);
       
    32   std::cout << "\nCalling run() (flow must be constant zero)..."<<std::endl;
       
    33   ts.reset();
       
    34   preflow_test.run();
       
    35   std::cout << "Elapsed time: " << ts << std::endl;
       
    36 
       
    37   Graph::NodeMap<bool> mincut(G);
       
    38   preflow_test.minMinCut(mincut); 
       
    39   int min_min_cut_value=0;
       
    40   Graph::NodeMap<bool> cut(G);
       
    41   preflow_test.minCut(cut); 
       
    42   int min_cut_value=0;
       
    43   Graph::NodeMap<bool> maxcut(G);
       
    44   preflow_test.maxMinCut(maxcut); 
       
    45   int max_min_cut_value=0;
       
    46   EdgeIt e;
       
    47   for(G.first(e); G.valid(e); G.next(e)) {
       
    48     int c=cap[e];
       
    49     if (mincut[G.source(e)] && !mincut[G.target(e)]) min_min_cut_value+=c;
       
    50     if (cut[G.source(e)] && !cut[G.target(e)]) min_cut_value+=c; 
       
    51     if (maxcut[G.source(e)] && !maxcut[G.target(e)]) max_min_cut_value+=c;
       
    52   }
       
    53 
       
    54   std::cout << "\nChecking the result: " <<std::endl;  
       
    55   std::cout << "Flow value: "<< preflow_test.flowValue() << std::endl;
       
    56   std::cout << "Min cut value: "<< min_cut_value << std::endl;
       
    57   std::cout << "Min min cut value: "<< min_min_cut_value << std::endl;
       
    58   std::cout << "Max min cut value: "<< max_min_cut_value << 
       
    59     std::endl;
       
    60 
       
    61   if ( preflow_test.flowValue() == min_cut_value &&
       
    62        min_cut_value == min_min_cut_value &&
       
    63        min_min_cut_value == max_min_cut_value )
       
    64     std::cout << "They are equal. " <<std::endl;  
       
    65   else {
       
    66     std::cout << "ERROR! They are not equal! " <<std::endl;  
       
    67     error=true;
       
    68   }
       
    69 
       
    70 
       
    71 
       
    72   Preflow<Graph, int> preflow_test2(G, s, t, cap, flow);
       
    73   std::cout << "\n\nCalling preflow(GEN_FLOW) with the given maximum flow..."<<std::endl;
       
    74   ts.reset();
       
    75   preflow_test2.preflow(preflow_test2.GEN_FLOW);
       
    76   std::cout << "Elapsed time: " << ts << std::endl;
       
    77 
       
    78   Graph::NodeMap<bool> mincut2(G);
       
    79   preflow_test.minMinCut(mincut2); 
       
    80   int min_min_cut2_value=0;
       
    81   Graph::NodeMap<bool> cut2(G);
       
    82   preflow_test.minCut(cut2); 
       
    83   int min_cut2_value=0;
       
    84   Graph::NodeMap<bool> maxcut2(G);
       
    85   preflow_test.maxMinCut(maxcut2); 
       
    86   int max_min_cut2_value=0;
       
    87   for(G.first(e); G.valid(e); G.next(e)) {
       
    88     int c=cap[e];
       
    89     if (mincut2[G.source(e)] && !mincut2[G.target(e)]) min_min_cut2_value+=c;
       
    90     if (cut2[G.source(e)] && !cut2[G.target(e)]) min_cut2_value+=c; 
       
    91     if (maxcut2[G.source(e)] && !maxcut2[G.target(e)]) max_min_cut2_value+=c;
       
    92   }
       
    93 
       
    94   std::cout << "\nThe given flow value is "
       
    95 	    << preflow_test2.flowValue();
       
    96 
       
    97   if ( preflow_test2.flowValue() == min_cut2_value &&
       
    98        min_cut2_value == min_min_cut2_value &&
       
    99        min_min_cut2_value == max_min_cut2_value )
       
   100     std::cout <<", which is equal to all three min cut values." 
       
   101 	      <<std::endl;  
       
   102   else {
       
   103     std::cout << "ERROR! It is not equal to all three min cut values! " 
       
   104 	      <<std::endl;  
       
   105     error=true;
       
   106   }
       
   107   
       
   108 
       
   109 
       
   110 
       
   111   Graph::EdgeMap<int> flow3(G,0);
       
   112   Preflow<Graph, int> preflow_test3(G, s, t, cap, flow3);
       
   113   std::cout << "\n\nCalling preflowPhase0(PREFLOW) on the constant zero flow..."<<std::endl;
       
   114   ts.reset();
       
   115   preflow_test3.preflowPhase0(preflow_test3.PREFLOW);
       
   116   std::cout << "Elapsed time: " << ts << std::endl;
       
   117   Graph::NodeMap<bool> actcut3(G);
       
   118   std::cout << "\nCalling actMinCut()..."<<std::endl;
       
   119   preflow_test3.actMinCut(actcut3); 
       
   120   std::cout << "Calling preflowPhase1() on the given flow..."<<std::endl;
       
   121   ts.reset();
       
   122   preflow_test3.preflowPhase1();
       
   123   std::cout << "Elapsed time: " << ts << std::endl;
       
   124   
       
   125   int act_min_cut3_value=0;
       
   126   
       
   127   Graph::NodeMap<bool> mincut3(G);
       
   128   preflow_test.minMinCut(mincut3); 
       
   129   int min_min_cut3_value=0;
       
   130   
       
   131   Graph::NodeMap<bool> cut3(G);
       
   132   preflow_test.minCut(cut3); 
       
   133   int min_cut3_value=0;
       
   134   
       
   135   Graph::NodeMap<bool> maxcut3(G);
       
   136   preflow_test.maxMinCut(maxcut3); 
       
   137   int max_min_cut3_value=0;
       
   138   
       
   139   for(G.first(e); G.valid(e); G.next(e)) {
       
   140     int c=cap[e];
       
   141     if (mincut3[G.source(e)] && !mincut3[G.target(e)]) min_min_cut3_value+=c;
       
   142     if (cut3[G.source(e)] && !cut3[G.target(e)]) min_cut3_value+=c; 
       
   143     if (maxcut3[G.source(e)] && !maxcut3[G.target(e)]) max_min_cut3_value+=c;
       
   144     if (actcut3[G.source(e)] && !actcut3[G.target(e)]) act_min_cut3_value+=c;
       
   145   }
       
   146 
       
   147  std::cout << "\nThe min cut value given by actMinCut() after phase 0 is "<<
       
   148    act_min_cut3_value;
       
   149 
       
   150   if ( preflow_test3.flowValue() == min_cut3_value &&
       
   151        min_cut3_value == min_min_cut3_value &&
       
   152        min_min_cut3_value == max_min_cut3_value &&
       
   153        max_min_cut3_value == act_min_cut3_value ) {
       
   154     std::cout << 
       
   155       ", which is equal to the given flow value and to all three min cut values after phase 1." 
       
   156 	      <<std::endl;  
       
   157   }
       
   158   else {
       
   159     std::cout << 
       
   160       "ERROR! It is not equal to the given flow value and to all three min cut values after phase 1! " 
       
   161 	      <<std::endl;  
       
   162     error=true;
       
   163   }
       
   164   
       
   165 
       
   166 
       
   167 
       
   168 
       
   169   Graph::EdgeMap<int> flow4(G,0);
       
   170   Preflow<Graph, int> preflow_test4(G, s, t, cap, flow4);
       
   171   std::cout << 
       
   172     "\n\nCalling preflow(PREFLOW) with the constant 0 flow, the result is f..."
       
   173 	    <<std::endl;
       
   174   preflow_test4.preflow(preflow_test4.PREFLOW);
       
   175 
       
   176   std::cout << "Swapping the source and the target, "<<std::endl;
       
   177   std::cout << "by calling resetSource(t) and resetTarget(s)..."
       
   178 	    <<std::endl;
       
   179   preflow_test4.resetSource(t);
       
   180   preflow_test4.resetTarget(s);
       
   181 
       
   182   std::cout << 
       
   183     "Calling preflow(PREFLOW) to find a maximum t-s flow starting with flow f..."
       
   184 	    <<std::endl;
       
   185   preflow_test4.preflow(preflow_test4.PREFLOW);
       
   186 
       
   187   Graph::NodeMap<bool> mincut4(G);
       
   188   preflow_test4.minMinCut(mincut4); 
       
   189   int min_min_cut4_value=0;
       
   190   Graph::NodeMap<bool> cut4(G);
       
   191   preflow_test4.minCut(cut4); 
       
   192   int min_cut4_value=0;
       
   193   Graph::NodeMap<bool> maxcut4(G);
       
   194   preflow_test4.maxMinCut(maxcut4); 
       
   195   int max_min_cut4_value=0;
       
   196   for(G.first(e); G.valid(e); G.next(e)) {
       
   197     int c=cap[e];
       
   198     if (mincut4[G.source(e)] && !mincut4[G.target(e)]) min_min_cut4_value+=c;
       
   199     if (cut4[G.source(e)] && !cut4[G.target(e)]) min_cut4_value+=c; 
       
   200     if (maxcut4[G.source(e)] && !maxcut4[G.target(e)]) max_min_cut4_value+=c;
       
   201   }
       
   202 
       
   203   std::cout << "\nThe given flow value is "
       
   204 	    << preflow_test4.flowValue();
       
   205   
       
   206   if ( preflow_test4.flowValue() == min_cut4_value &&
       
   207        min_cut4_value == min_min_cut4_value &&
       
   208        min_min_cut4_value == max_min_cut4_value )
       
   209     std::cout <<", which is equal to all three min cut values." 
       
   210 	      <<std::endl;  
       
   211   else {
       
   212     std::cout << "ERROR! It is not equal to all three min cut values! " 
       
   213 	      <<std::endl;  
       
   214     error=true;
       
   215   }
       
   216 
       
   217 
       
   218 
       
   219 
       
   220   Graph::EdgeMap<int> flow5(G,0);
       
   221   std::cout << "Resetting the stored flow to constant zero, by calling resetFlow..."
       
   222 	    <<std::endl;
       
   223   preflow_test4.resetFlow(flow5);
       
   224   std::cout << 
       
   225     "Calling preflow(GEN_FLOW) to find a maximum t-s flow "<<std::endl;
       
   226   std::cout << 
       
   227     "starting with this constant zero flow..." <<std::endl;
       
   228   preflow_test4.preflow(preflow_test4.GEN_FLOW);
       
   229 
       
   230   Graph::NodeMap<bool> mincut5(G);
       
   231   preflow_test4.minMinCut(mincut5); 
       
   232   int min_min_cut5_value=0;
       
   233   Graph::NodeMap<bool> cut5(G);
       
   234   preflow_test4.minCut(cut5); 
       
   235   int min_cut5_value=0;
       
   236   Graph::NodeMap<bool> maxcut5(G);
       
   237   preflow_test4.maxMinCut(maxcut5); 
       
   238   int max_min_cut5_value=0;
       
   239   for(G.first(e); G.valid(e); G.next(e)) {
       
   240     int c=cap[e];
       
   241     if (mincut5[G.source(e)] && !mincut5[G.target(e)]) min_min_cut5_value+=c;
       
   242     if (cut5[G.source(e)] && !cut5[G.target(e)]) min_cut5_value+=c; 
       
   243     if (maxcut5[G.source(e)] && !maxcut5[G.target(e)]) max_min_cut5_value+=c;
       
   244   }
       
   245 
       
   246   std::cout << "\nThe given flow value is "
       
   247 	    << preflow_test4.flowValue();
       
   248   
       
   249   if ( preflow_test4.flowValue() == min_cut5_value &&
       
   250        min_cut5_value == min_min_cut5_value &&
       
   251        min_min_cut5_value == max_min_cut5_value )
       
   252     std::cout <<", which is equal to all three min cut values." 
       
   253 	      <<std::endl<<std::endl;  
       
   254   else {
       
   255     std::cout << "ERROR! It is not equal to all three min cut values! " 
       
   256 	      <<std::endl;  
       
   257     error=true;
       
   258   }
       
   259   
       
   260   if (error) std::cout <<"\nThere was some error in the results!\n"<<std::endl; 
       
   261   else std::cout <<"\nThere was no error in the results.\n"<<std::endl; 
       
   262 
       
   263   return 0;
       
   264 }