src/work/marci/lp/max_flow_by_lp.cc
author alpar
Sun, 17 Apr 2005 18:57:22 +0000
changeset 1364 ee5959aa4410
parent 1025 3b1ad8bc21da
permissions -rw-r--r--
- compile failure fixed
- newLp(), copyLp() added
- more doc.
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// -*- c++ -*-
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#include <iostream>
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#include <fstream>
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#include <lemon/smart_graph.h>
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#include <lemon/list_graph.h>
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#include <lemon/dimacs.h>
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#include <lemon/time_measure.h>
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//#include <graph_wrapper.h>
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#include <lemon/preflow.h>
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#include <augmenting_flow.h>
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//#include <preflow_res.h>
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//#include <lp_solver_wrapper_2.h>
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#include <min_cost_gen_flow.h>
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// Use a DIMACS max flow file as stdin.
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// max_flow_demo < dimacs_max_flow_file
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using namespace lemon;
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int main(int, char **) {
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  typedef ListGraph MutableGraph;
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  typedef ListGraph Graph;
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  typedef Graph::Node Node;
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  typedef Graph::Edge Edge;
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  typedef Graph::EdgeIt EdgeIt;
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  Graph g;
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  Node s, t;
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  Graph::EdgeMap<int> cap(g);
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  //readDimacsMaxFlow(std::cin, g, s, t, cap);
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  readDimacs(std::cin, g, cap, s, t);
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  Timer ts;
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  Graph::EdgeMap<int> flow(g); //0 flow
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  Preflow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
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    max_flow_test(g, s, t, cap, flow);
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  AugmentingFlow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> > 
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    augmenting_flow_test(g, s, t, cap, flow);
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  Graph::NodeMap<bool> cut(g);
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  {
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    std::cout << "preflow ..." << std::endl;
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    ts.reset();
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    max_flow_test.run();
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    std::cout << "elapsed time: " << ts << std::endl;
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    std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
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    max_flow_test.minCut(cut);
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    for (EdgeIt e(g); e!=INVALID; ++e) {
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      if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
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	std::cout << "Slackness does not hold!" << std::endl;
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      if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
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	std::cout << "Slackness does not hold!" << std::endl;
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    }
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  }
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//   {
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//     std::cout << "preflow ..." << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
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//     ts.reset();
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//     max_flow_test.preflow(Preflow<Graph, int, Graph::EdgeMap<int>, Graph::EdgeMap<int> >::GEN_FLOW);
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//     std::cout << "elapsed time: " << ts << std::endl;
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//     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
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//       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
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// 	std::cout << "Slackness does not hold!" << std::endl;
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//       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
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// 	std::cout << "Slackness does not hold!" << std::endl;
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//     }
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//   }
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//   {
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//     std::cout << "wrapped preflow ..." << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
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//     ts.reset();
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//     pre_flow_res.run();
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//     std::cout << "elapsed time: " << ts << std::endl;
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//     std::cout << "flow value: "<< pre_flow_test.flowValue() << std::endl;
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//   }
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  {
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    std::cout << "physical blocking flow augmentation ..." << std::endl;
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    for (EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
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    ts.reset();
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    int i=0;
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    while (augmenting_flow_test.augmentOnBlockingFlow<MutableGraph>()) { ++i; }
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    std::cout << "elapsed time: " << ts << std::endl;
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    std::cout << "number of augmentation phases: " << i << std::endl; 
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    std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
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    for (EdgeIt e(g); e!=INVALID; ++e) {
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      if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
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	std::cout << "Slackness does not hold!" << std::endl;
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      if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
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	std::cout << "Slackness does not hold!" << std::endl;
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    }
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  }
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//   {
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//     std::cout << "faster physical blocking flow augmentation ..." << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
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//     ts.reset();
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//     int i=0;
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//     while (max_flow_test.augmentOnBlockingFlow1<MutableGraph>()) { ++i; }
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//     std::cout << "elapsed time: " << ts << std::endl;
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//     std::cout << "number of augmentation phases: " << i << std::endl; 
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//     std::cout << "flow value: "<< max_flow_test.flowValue() << std::endl;
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//   }
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  {
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    std::cout << "on-the-fly blocking flow augmentation ..." << std::endl;
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    for (EdgeIt e(g); e!=INVALID; ++e) flow.set(e, 0);
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    ts.reset();
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    int i=0;
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    while (augmenting_flow_test.augmentOnBlockingFlow2()) { ++i; }
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    std::cout << "elapsed time: " << ts << std::endl;
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    std::cout << "number of augmentation phases: " << i << std::endl; 
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    std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
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    for (EdgeIt e(g); e!=INVALID; ++e) {
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      if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
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	std::cout << "Slackness does not hold!" << std::endl;
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      if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
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	std::cout << "Slackness does not hold!" << std::endl;
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    }
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  }
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//   {
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//     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
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//     ts.reset();
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//     int i=0;
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//     while (augmenting_flow_test.augmentOnShortestPath()) { ++i; }
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//     std::cout << "elapsed time: " << ts << std::endl;
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//     std::cout << "number of augmentation phases: " << i << std::endl; 
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//     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
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//       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
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// 	std::cout << "Slackness does not hold!" << std::endl;
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//       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
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// 	std::cout << "Slackness does not hold!" << std::endl;
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//     }
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//   }
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//   {
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//     std::cout << "on-the-fly shortest path augmentation ..." << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) flow.set(e, 0);
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//     ts.reset();
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//     int i=0;
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//     while (augmenting_flow_test.augmentOnShortestPath2()) { ++i; }
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//     std::cout << "elapsed time: " << ts << std::endl;
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//     std::cout << "number of augmentation phases: " << i << std::endl; 
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//     std::cout << "flow value: "<< augmenting_flow_test.flowValue() << std::endl;
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//     FOR_EACH_LOC(Graph::EdgeIt, e, g) {
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//       if (cut[g.source(e)] && !cut[g.target(e)] && !flow[e]==cap[e]) 
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// 	std::cout << "Slackness does not hold!" << std::endl;
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//       if (!cut[g.source(e)] && cut[g.target(e)] && flow[e]>0) 
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// 	std::cout << "Slackness does not hold!" << std::endl;
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//     }
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//   }
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  ts.reset();
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  Edge e=g.addEdge(t, s);
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  Graph::EdgeMap<int> cost(g, 0);
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  cost.set(e, -1);
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  cap.set(e, 10000);
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  typedef ConstMap<Node, int> Excess;
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  Excess excess(0);
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  typedef ConstMap<Edge, int> LCap;
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  LCap lcap(0);
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  MinCostGenFlow<Graph, int, Excess, LCap> 
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    min_cost(g, excess, lcap, cap, flow, cost); 
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  min_cost.feasible();
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  min_cost.runByLP();
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  std::cout << "elapsed time: " << ts << std::endl;
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  std::cout << "flow value: "<< flow[e] << std::endl;
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}