demo/lgf_demo.cc
author Balazs Dezso <deba@inf.elte.hu>
Thu, 24 Jun 2010 09:27:53 +0200
changeset 891 bb70ad62c95f
parent 294 cbe3ec2d59d2
permissions -rw-r--r--
Fix critical bug in preflow (#372)

The wrong transition between the bound decrease and highest active
heuristics caused the bug. The last node chosen in bound decrease mode
is used in the first iteration in highest active mode.
     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
     2  *
     3  * This file is a part of LEMON, a generic C++ optimization library.
     4  *
     5  * Copyright (C) 2003-2009
     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 graph input and output
    22 ///
    23 /// This program gives an example of how to read and write a digraph
    24 /// and additional maps from/to a stream or a file using the
    25 /// \ref lgf-format "LGF" format.
    26 ///
    27 /// The \c "digraph.lgf" file:
    28 /// \include digraph.lgf
    29 ///
    30 /// And the program which reads it and prints the digraph to the
    31 /// standard output:
    32 /// \include lgf_demo.cc
    33 
    34 #include <iostream>
    35 #include <lemon/smart_graph.h>
    36 #include <lemon/lgf_reader.h>
    37 #include <lemon/lgf_writer.h>
    38 
    39 using namespace lemon;
    40 
    41 int main() {
    42   SmartDigraph g;
    43   SmartDigraph::ArcMap<int> cap(g);
    44   SmartDigraph::Node s, t;
    45 
    46   try {
    47     digraphReader(g, "digraph.lgf"). // read the directed graph into g
    48       arcMap("capacity", cap).       // read the 'capacity' arc map into cap
    49       node("source", s).             // read 'source' node to s
    50       node("target", t).             // read 'target' node to t
    51       run();
    52   } catch (Exception& error) { // check if there was any error
    53     std::cerr << "Error: " << error.what() << std::endl;
    54     return -1;
    55   }
    56 
    57   std::cout << "A digraph is read from 'digraph.lgf'." << std::endl;
    58   std::cout << "Number of nodes: " << countNodes(g) << std::endl;
    59   std::cout << "Number of arcs: " << countArcs(g) << std::endl;
    60 
    61   std::cout << "We can write it to the standard output:" << std::endl;
    62 
    63   digraphWriter(g).                // write g to the standard output
    64     arcMap("capacity", cap).       // write cap into 'capacity'
    65     node("source", s).             // write s to 'source'
    66     node("target", t).             // write t to 'target'
    67     run();
    68 
    69   return 0;
    70 }