src/work/marci/lp/max_flow_by_lp.cc
author alpar
Sat, 13 Nov 2004 12:53:28 +0000
changeset 986 e997802b855c
parent 921 818510fa3d99
child 1014 aae850a2394d
permissions -rw-r--r--
Naming changes:
- head -> target
- tail -> source
     1 // -*- c++ -*-
     2 #include <iostream>
     3 #include <fstream>
     4 
     5 #include <sage_graph.h>
     6 #include <lemon/smart_graph.h>
     7 #include <lemon/dimacs.h>
     8 #include <lemon/time_measure.h>
     9 //#include <graph_wrapper.h>
    10 #include <lemon/max_flow.h>
    11 #include <augmenting_flow.h>
    12 //#include <preflow_res.h>
    13 #include <for_each_macros.h>
    14 #include <lp_solver_wrapper.h>
    15 
    16 using namespace lemon;
    17 
    18 // Use a DIMACS max flow file as stdin.
    19 // max_flow_demo < dimacs_max_flow_file
    20 
    21 template<typename Edge, typename EdgeIndexMap> 
    22 class PrimalMap {
    23 protected:
    24   LPSolverWrapper* lp;
    25   EdgeIndexMap* edge_index_map;
    26 public:
    27   PrimalMap(LPSolverWrapper& _lp, EdgeIndexMap& _edge_index_map) : 
    28     lp(&_lp), edge_index_map(&_edge_index_map) { }
    29   double operator[](Edge e) const { 
    30     return lp->getPrimal((*edge_index_map)[e]);
    31   }
    32 };
    33 
    34 int main(int, char **) {
    35 
    36   typedef SageGraph MutableGraph;
    37   //typedef SmartGraph Graph;
    38   typedef SageGraph Graph;
    39   typedef Graph::Node Node;
    40   typedef Graph::EdgeIt EdgeIt;
    41 
    42   Graph g;
    43 
    44   Node s, t;
    45   Graph::EdgeMap<int> cap(g);
    46   //readDimacsMaxFlow(std::cin, g, s, t, cap);
    47   readDimacs(std::cin, g, cap, s, t);
    48   Timer ts;
    49   Graph::EdgeMap<int> flow(g); //0 flow
    50   MaxFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    51     max_flow_test(g, s, t, cap, flow);
    52   AugmentingFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
    53     augmenting_flow_test(g, s, t, cap, flow);
    54   
    55   Graph::NodeMap<bool> cut(g);
    56 
    57   {
    58     std::cout << "preflow ..." << std::endl;
    59     ts.reset();
    60     max_flow_test.run();
    61     std::cout << "elapsed time: " << ts << std::endl;
    62     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    63     max_flow_test.actMinCut(cut);
    64 
    65     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
    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 << "preflow ..." << std::endl;
    75 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    76 //     ts.reset();
    77 //     max_flow_test.preflow(MaxFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> >::GEN_FLOW);
    78 //     std::cout << "elapsed time: " << ts << std::endl;
    79 //     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
    80 
    81 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
    82 //       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
    83 // 	std::cout << "Slackness does not hold!" << std::endl;
    84 //       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
    85 // 	std::cout << "Slackness does not hold!" << std::endl;
    86 //     }
    87 //   }
    88 
    89 //   {
    90 //     std::cout << "wrapped preflow ..." << std::endl;
    91 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
    92 //     ts.reset();
    93 //     pre_flow_res.run();
    94 //     std::cout << "elapsed time: " << ts << std::endl;
    95 //     std::cout << "flow value: "<< pre_flow_test.flowValue() << std::endl;
    96 //   }
    97 
    98   {
    99     std::cout << "physical blocking flow augmentation ..." << std::endl;
   100     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   101     ts.reset();
   102     int i=0;
   103     while (augmenting_flow_test.augmentOnBlockingFlow<MutableGraph>()) { ++i; }
   104     std::cout << "elapsed time: " << ts << std::endl;
   105     std::cout << "number of augmentation phases: " << i << std::endl; 
   106     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   107 
   108     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   109       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   110 	std::cout << "Slackness does not hold!" << std::endl;
   111       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   112 	std::cout << "Slackness does not hold!" << std::endl;
   113     }
   114   }
   115 
   116 //   {
   117 //     std::cout << "faster physical blocking flow augmentation ..." << std::endl;
   118 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   119 //     ts.reset();
   120 //     int i=0;
   121 //     while (max_flow_test.augmentOnBlockingFlow1<MutableGraph>()) { ++i; }
   122 //     std::cout << "elapsed time: " << ts << std::endl;
   123 //     std::cout << "number of augmentation phases: " << i << std::endl; 
   124 //     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
   125 //   }
   126 
   127   {
   128     std::cout << "on-the-fly blocking flow augmentation ..." << std::endl;
   129     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   130     ts.reset();
   131     int i=0;
   132     while (augmenting_flow_test.augmentOnBlockingFlow2()) { ++i; }
   133     std::cout << "elapsed time: " << ts << std::endl;
   134     std::cout << "number of augmentation phases: " << i << std::endl; 
   135     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   136 
   137     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   138       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   139 	std::cout << "Slackness does not hold!" << std::endl;
   140       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   141 	std::cout << "Slackness does not hold!" << std::endl;
   142     }
   143   }
   144 
   145 //   {
   146 //     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   147 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   148 //     ts.reset();
   149 //     int i=0;
   150 //     while (augmenting_flow_test.augmentOnShortestPath()) { ++i; }
   151 //     std::cout << "elapsed time: " << ts << std::endl;
   152 //     std::cout << "number of augmentation phases: " << i << std::endl; 
   153 //     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   154 
   155 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   156 //       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   157 // 	std::cout << "Slackness does not hold!" << std::endl;
   158 //       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   159 // 	std::cout << "Slackness does not hold!" << std::endl;
   160 //     }
   161 //   }
   162 
   163 //   {
   164 //     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
   165 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
   166 //     ts.reset();
   167 //     int i=0;
   168 //     while (augmenting_flow_test.augmentOnShortestPath2()) { ++i; }
   169 //     std::cout << "elapsed time: " << ts << std::endl;
   170 //     std::cout << "number of augmentation phases: " << i << std::endl; 
   171 //     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
   172 
   173 //     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
   174 //       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
   175 // 	std::cout << "Slackness does not hold!" << std::endl;
   176 //       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
   177 // 	std::cout << "Slackness does not hold!" << std::endl;
   178 //     }
   179 //   }
   180 
   181   ts.reset();
   182   LPSolverWrapper lp;
   183   lp.setMaximize();
   184   typedef LPSolverWrapper::ColIt ColIt;
   185   typedef LPSolverWrapper::RowIt RowIt;
   186   typedef Graph::EdgeMap<ColIt> EdgeIndexMap;
   187   EdgeIndexMap edge_index_map(g);
   188   PrimalMap<Graph::Edge, EdgeIndexMap> lp_flow(lp, edge_index_map);
   189   Graph::EdgeIt e;
   190   for (g.first(e); g.valid(e); g.next(e)) {
   191     ColIt col_it=lp.addCol();
   192     edge_index_map.set(e, col_it);
   193     lp.setColBounds(col_it, LPX_DB, 0.0, cap[e]);
   194   }
   195   Graph::NodeIt n;
   196   for (g.first(n); g.valid(n); g.next(n)) {
   197     if (n!=s) {
   198       //hurokelek miatt
   199       Graph::EdgeMap<int> coeffs(g, 0);
   200       {
   201 	Graph::InEdgeIt e;
   202 	for (g.first(e, n); g.valid(e); g.next(e)) coeffs.set(e, coeffs[e]+1);
   203       }
   204       {
   205 	Graph::OutEdgeIt e;
   206 	for (g.first(e, n); g.valid(e); g.next(e)) coeffs.set(e, coeffs[e]-1);
   207       }
   208       if (n==t) {
   209 	Graph::EdgeIt e;
   210 	//std::vector< std::pair<ColIt, double> > row;
   211 	for (g.first(e); g.valid(e); g.next(e)) {
   212 	  if (coeffs[e]!=0) 
   213 	    lp.setObjCoef(edge_index_map[e], coeffs[e]);
   214 	}
   215       } else  {
   216 	RowIt row_it=lp.addRow();
   217 	Graph::EdgeIt e;
   218 	std::vector< std::pair<ColIt, double> > row;
   219 	for (g.first(e); g.valid(e); g.next(e)) {
   220 	  if (coeffs[e]!=0) 
   221 	    row.push_back(std::make_pair(edge_index_map[e], coeffs[e]));
   222 	}	
   223 	lp.setRowCoeffs(row_it, row.begin(), row.end());
   224 	lp.setRowBounds(row_it, LPX_FX, 0.0, 0.0);
   225       }
   226     }
   227   }
   228   lp.solveSimplex();
   229   std::cout << "flow value: "<< lp.getObjVal() << std::endl;
   230   std::cout << "elapsed time: " << ts << std::endl;
   231 
   232   return 0;
   233 }