circulation_demo.cc File Reference

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Detailed Description

This demo program reads a general network circulation problem from the file 'circulation-input.lgf', runs the preflow based algorithm for finding a feasible solution and writes the output to 'circulation-input.lgf'

/* -*- C++ -*-
 *
 * This file is a part of LEMON, a generic C++ optimization library
 *
 * Copyright (C) 2003-2008
 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
 *
 * Permission to use, modify and distribute this software is granted
 * provided that this copyright notice appears in all copies. For
 * precise terms see the accompanying LICENSE file.
 *
 * This software is provided "AS IS" with no warranty of any kind,
 * express or implied, and with no claim as to its suitability for any
 * purpose.
 *
 */


#include <iostream>

#include <lemon/list_graph.h>
#include <lemon/circulation.h>
#include <lemon/graph_reader.h>
#include <lemon/graph_writer.h>

using namespace lemon;


int main (int, char*[])
{

    typedef ListGraph Graph;
    typedef Graph::Node Node;
    typedef Graph::NodeIt NodeIt;
    typedef Graph::Edge Edge;
    typedef Graph::EdgeIt EdgeIt;
    typedef Graph::EdgeMap<int> EdgeMap;
    typedef Graph::NodeMap<int> NodeMap;
    typedef Graph::NodeMap<double> DNodeMap;

    Graph g;
    EdgeMap lo(g);
    EdgeMap up(g);
    NodeMap delta(g);
    NodeMap nid(g);
    EdgeMap eid(g);
    DNodeMap cx(g);
    DNodeMap cy(g);
    
    GraphReader<Graph>("circulation-input.lgf", g).
      readEdgeMap("lo_cap", lo).
      readEdgeMap("up_cap", up).
      readNodeMap("delta", delta).
      readEdgeMap("label", eid).
      readNodeMap("label", nid).
      readNodeMap("coordinates_x", cx).
      readNodeMap("coordinates_y", cy).
      run();

    Circulation<Graph> gen(g,lo,up,delta);
    bool ret=gen.run();
    if(ret)
      {
        std::cout << "\nA feasible flow has been found.\n";
        if(!gen.checkFlow()) std::cerr << "Oops!!!\n";
        GraphWriter<Graph>("circulation-output.lgf", g).
          writeEdgeMap("lo_cap", lo).
          writeEdgeMap("up_cap", up).
          writeEdgeMap("flow", gen.flowMap()).
          writeNodeMap("delta", delta).
          writeEdgeMap("label", eid).
          writeNodeMap("label", nid).
          writeNodeMap("coordinates_x", cx).
          writeNodeMap("coordinates_y", cy).
          run();
      }
    else {
      std::cout << "\nThere is no such a flow\n";
      Graph::NodeMap<int> bar(g);
      gen.barrierMap(bar);
      if(!gen.checkBarrier()) std::cerr << "Dual Oops!!!\n";

      GraphWriter<Graph>("circulation-output.lgf", g).
        writeEdgeMap("lo_cap", lo).
        writeEdgeMap("up_cap", up).
        writeNodeMap("barrier", bar).
        writeNodeMap("delta", delta).
        writeEdgeMap("label", eid).
        writeNodeMap("label", nid).
        writeNodeMap("coordinates_x", cx).
        writeNodeMap("coordinates_y", cy).
        run();
    }
  std::cout << "The output is written to file 'circulation-output.lgf'\n\n";
    
}

#include <iostream>
#include <lemon/list_graph.h>
#include <lemon/circulation.h>
#include <lemon/graph_reader.h>
#include <lemon/graph_writer.h>