demo/circulation_demo.cc
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     1 /* -*- C++ -*-
       
     2  *
       
     3  * This file is a part of LEMON, a generic C++ optimization library
       
     4  *
       
     5  * Copyright (C) 2003-2006
       
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
       
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
       
     8  *
       
     9  * Permission to use, modify and distribute this software is granted
       
    10  * provided that this copyright notice appears in all copies. For
       
    11  * precise terms see the accompanying LICENSE file.
       
    12  *
       
    13  * This software is provided "AS IS" with no warranty of any kind,
       
    14  * express or implied, and with no claim as to its suitability for any
       
    15  * purpose.
       
    16  *
       
    17  */
       
    18 
       
    19 ///\ingroup demos
       
    20 ///\file
       
    21 ///\brief Demonstrating the usage of LEMON's General Flow algorithm
       
    22 ///
       
    23 /// This demo program reads a general network circulation problem from the
       
    24 /// file 'circulation-input.lgf', runs the preflow based algorithm for
       
    25 /// finding a feasible solution and writes the output
       
    26 /// to 'circulation-input.lgf'
       
    27 ///
       
    28 /// \include circulation_demo.cc
       
    29 
       
    30 #include <iostream>
       
    31 
       
    32 #include <lemon/list_graph.h>
       
    33 #include <lemon/circulation.h>
       
    34 #include <lemon/graph_reader.h>
       
    35 #include <lemon/graph_writer.h>
       
    36 
       
    37 using namespace lemon;
       
    38 
       
    39 
       
    40 int main (int, char*[])
       
    41 {
       
    42 
       
    43     typedef ListGraph Graph;
       
    44     typedef Graph::Node Node;
       
    45     typedef Graph::NodeIt NodeIt;
       
    46     typedef Graph::Edge Edge;
       
    47     typedef Graph::EdgeIt EdgeIt;
       
    48     typedef Graph::EdgeMap<int> EdgeMap;
       
    49     typedef Graph::NodeMap<int> NodeMap;
       
    50     typedef Graph::NodeMap<double> DNodeMap;
       
    51 
       
    52     Graph g;
       
    53     EdgeMap lo(g);
       
    54     EdgeMap up(g);
       
    55     EdgeMap x(g);
       
    56     NodeMap delta(g);
       
    57     NodeMap nid(g);
       
    58     EdgeMap eid(g);
       
    59     DNodeMap cx(g);
       
    60     DNodeMap cy(g);
       
    61     
       
    62     GraphReader<Graph>("circulation-input.lgf", g).
       
    63       readEdgeMap("lo_cap", lo).
       
    64       readEdgeMap("up_cap", up).
       
    65       readNodeMap("delta", delta).
       
    66       readEdgeMap("label", eid).
       
    67       readNodeMap("label", nid).
       
    68       readNodeMap("coordinates_x", cx).
       
    69       readNodeMap("coordinates_y", cy).
       
    70       run();
       
    71 
       
    72     Circulation<Graph,int> gen(g,lo,up,delta,x);
       
    73     int ret=gen.run();
       
    74     if(ret==-1)
       
    75       {
       
    76 	std::cout << "\nA feasible flow has been found.\n";
       
    77 	if(!gen.checkX(x)) std::cerr << "Oops!!!\n";
       
    78 	GraphWriter<Graph>("circulation-output.lgf", g).
       
    79 	  writeEdgeMap("lo_cap", lo).
       
    80 	  writeEdgeMap("up_cap", up).
       
    81 	  writeEdgeMap("flow", x).
       
    82 	  writeNodeMap("delta", delta).
       
    83 	  writeEdgeMap("label", eid).
       
    84 	  writeNodeMap("label", nid).
       
    85 	  writeNodeMap("coordinates_x", cx).
       
    86 	  writeNodeMap("coordinates_y", cy).
       
    87 	  run();
       
    88       }
       
    89     else {
       
    90       std::cout << "\nThere is no such a flow\n";
       
    91       Graph::NodeMap<int> bar(g);
       
    92       gen.barrier(bar,ret);
       
    93       if(!gen.checkBarrier(bar)) std::cerr << "Dual Oops!!!\n";
       
    94 
       
    95       GraphWriter<Graph>("circulation-output.lgf", g).
       
    96 	writeEdgeMap("lo_cap", lo).
       
    97 	writeEdgeMap("up_cap", up).
       
    98 	writeNodeMap("barrier", bar).
       
    99 	writeNodeMap("delta", delta).
       
   100 	writeEdgeMap("label", eid).
       
   101 	writeNodeMap("label", nid).
       
   102 	writeNodeMap("coordinates_x", cx).
       
   103 	writeNodeMap("coordinates_y", cy).
       
   104 	run();
       
   105     }
       
   106   std::cout << "The output is written to file 'circulation-output.lgf'\n\n";
       
   107     
       
   108 }