source: lemon-0.x/src/work/marci/lp/min_cost_gen_flow.h @ 1025:3b1ad8bc21da

// -*- c++ -*-
#ifndef LEMON_MIN_COST_GEN_FLOW_H
#define LEMON_MIN_COST_GEN_FLOW_H
#include <iostream>
//#include <fstream>

#include <lemon/smart_graph.h>
#include <lemon/list_graph.h>
//#include <lemon/dimacs.h>
//#include <lemon/time_measure.h>
//#include <graph_wrapper.h>
#include <lemon/preflow.h>
//#include <augmenting_flow.h>
//#include <preflow_res.h>
#include <../merge_node_graph_wrapper.h>
#include <lemon/../work/marci/lp/lp_solver_wrapper.h>

namespace lemon {

  template<typename Edge, typename EdgeIndexMap> 
  class PrimalMap {
  protected:
    LPSolverWrapper* lp;
    EdgeIndexMap* edge_index_map;
  public:
    PrimalMap(LPSolverWrapper& _lp, EdgeIndexMap& _edge_index_map) : 
      lp(&_lp), edge_index_map(&_edge_index_map) { }
    double operator[](Edge e) const { 
      return lp->getPrimal((*edge_index_map)[e]);
    }
  };

  // excess: rho-delta
  template <typename Graph, typename Num,
            typename Excess=typename Graph::template NodeMap<Num>, 
            typename LCapMap=typename Graph::template EdgeMap<Num>,
            typename CapMap=typename Graph::template EdgeMap<Num>,
            typename FlowMap=typename Graph::template EdgeMap<Num>,
            typename CostMap=typename Graph::template EdgeMap<Num> >
  class MinCostGenFlow {
  protected:
    const Graph& g;
    const Excess& excess;
    const LCapMap& lcapacity;
    const CapMap& capacity;
    FlowMap& flow;
    const CostMap& cost;
  public:
    MinCostGenFlow(const Graph& _g, const Excess& _excess, 
                   const LCapMap& _lcapacity, const CapMap& _capacity, 
                   FlowMap& _flow, 
                   const CostMap& _cost) :
      g(_g), excess(_excess), lcapacity(_lcapacity),
      capacity(_capacity), flow(_flow), cost(_cost) { }
    bool feasible() {
      //      std::cout << "making new vertices..." << std::endl; 
      typedef ListGraph Graph2;
      Graph2 g2;
      typedef MergeEdgeGraphWrapper<const Graph, Graph2> GW;
      //      std::cout << "merging..." << std::endl; 
      GW gw(g, g2);
      typename GW::Node s(INVALID, g2.addNode(), true);
      typename GW::Node t(INVALID, g2.addNode(), true);
      typedef SmartGraph Graph3;
      //      std::cout << "making extender graph..." << std::endl; 
      typedef NewEdgeSetGraphWrapper2<GW, Graph3> GWW;
//       {
//      checkConcept<StaticGraph, GWW>();   
//       }
      GWW gww(gw);
      typedef AugmentingGraphWrapper<GW, GWW> GWWW;
      GWWW gwww(gw, gww);

      //      std::cout << "making new edges..." << std::endl; 
      typename GWWW::template EdgeMap<Num> translated_cap(gwww);

      for (typename GW::EdgeIt e(gw); e!=INVALID; ++e)
      translated_cap.set(typename GWWW::Edge(e,INVALID,false), 
                         capacity[e]-lcapacity[e]);

      Num expected=0;

      //      std::cout << "making new edges 2..." << std::endl; 
      for (typename Graph::NodeIt n(g); n!=INVALID; ++n) {
        Num a=0;
        for (typename Graph::InEdgeIt e(g, n); e!=INVALID; ++e)
          a+=lcapacity[e];
        for (typename Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) 
          a-=lcapacity[e];
        if (excess[n]>a) {
          typename GWW::Edge e=
            gww.addEdge(typename GW::Node(n,INVALID,false), t);
          translated_cap.set(typename GWWW::Edge(INVALID, e, true), 
                             excess[n]-a);
        }
        if (excess[n]<a) {
          typename GWW::Edge e=
            gww.addEdge(s, typename GW::Node(n,INVALID,false));
          translated_cap.set(typename GWWW::Edge(INVALID, e, true), 
                             a-excess[n]);
          expected+=a-excess[n];
        }
      }

      //      std::cout << "preflow..." << std::endl; 
      typename GWWW::template EdgeMap<Num> translated_flow(gwww, 0);
      Preflow<GWWW, Num> preflow(gwww, s, t, 
                                 translated_cap, translated_flow);
      preflow.run();
      //      std::cout << "fv: " << preflow.flowValue() << std::endl; 
      //      std::cout << "expected: " << expected << std::endl; 

      for (typename Graph::EdgeIt e(g); e!=INVALID; ++e) {
        typename GW::Edge ew(e, INVALID, false);
        typename GWWW::Edge ewww(ew, INVALID, false);
        flow.set(e, translated_flow[ewww]+lcapacity[e]);
      }
      return (expected>=preflow.flowValue());
    }
    void run() {
      LPSolverWrapper lp;
      lp.setMinimize();
      typedef LPSolverWrapper::ColIt ColIt;
      typedef LPSolverWrapper::RowIt RowIt;
      typedef typename Graph::template EdgeMap<ColIt> EdgeIndexMap;
      EdgeIndexMap edge_index_map(g);
      PrimalMap<typename Graph::Edge, EdgeIndexMap> lp_flow(lp, edge_index_map);
      for (typename Graph::EdgeIt e(g); e!=INVALID; ++e) {
        ColIt col_it=lp.addCol();
        edge_index_map.set(e, col_it);
        if (lcapacity[e]==capacity[e])
          lp.setColBounds(col_it, LPX_FX, lcapacity[e], capacity[e]);
        else 
          lp.setColBounds(col_it, LPX_DB, lcapacity[e], capacity[e]);
        lp.setObjCoef(col_it, cost[e]);
      }
      for (typename Graph::NodeIt n(g); n!=INVALID; ++n) {
        typename Graph::template EdgeMap<Num> coeffs(g, 0);
        for (typename Graph::InEdgeIt e(g, n); e!=INVALID; ++e)
        coeffs.set(e, coeffs[e]+1);
        for (typename Graph::OutEdgeIt e(g, n); e!=INVALID; ++e) 
        coeffs.set(e, coeffs[e]-1);
        RowIt row_it=lp.addRow();
        typename std::vector< std::pair<ColIt, double> > row;
        //std::cout << "node:" <<g.id(n)<<std::endl;
        for (typename Graph::EdgeIt e(g); e!=INVALID; ++e) {
          if (coeffs[e]!=0) {
            //std::cout << " edge:" <<g.id(e)<<" "<<coeffs[e];
            row.push_back(std::make_pair(edge_index_map[e], coeffs[e]));
          }
        }
        //std::cout << std::endl;
        lp.setRowCoeffs(row_it, row.begin(), row.end());
        lp.setRowBounds(row_it, LPX_FX, 0.0, 0.0);
      }
      lp.solveSimplex();
      //std::cout << lp.colNum() << std::endl;
      //std::cout << lp.rowNum() << std::endl;
      //std::cout << "flow value: "<< lp.getObjVal() << std::endl;
      for (typename Graph::EdgeIt e(g); e!=INVALID; ++e) 
      flow.set(e, lp_flow[e]);
    }
  };

} // namespace lemon

#endif //LEMON_MIN_COST_GEN_FLOW_H