COIN-OR::LEMON - Graph Library

source: lemon-0.x/demo/sub_graph_adaptor_demo.cc @ 1636:260ac104190f

Last change on this file since 1636:260ac104190f was 1636:260ac104190f, checked in by Akos Ladanyi, 14 years ago

Added missing copyright headers, and corrected the file names in some of them.

File size: 3.6 KB
Line 
1/* -*- C++ -*-
2 * demo/sub_graph_adaptor_demo.cc - Part of LEMON, a generic C++ optimization
3 * library
4 *
5 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
6 * (Egervary Research Group on Combinatorial Optimization, EGRES).
7 *
8 * Permission to use, modify and distribute this software is granted
9 * provided that this copyright notice appears in all copies. For
10 * precise terms see the accompanying LICENSE file.
11 *
12 * This software is provided "AS IS" with no warranty of any kind,
13 * express or implied, and with no claim as to its suitability for any
14 * purpose.
15 *
16 */
17
18///\ingroup demos
19///\file
20///\brief Computing maximum number of edge-disjoint shortest paths
21///
22/// This program computes a maximum number of edge-disjoint shortest paths
23/// between nodes \c s and \c t.
24
25
26// Use a DIMACS max flow file as input.
27// sub_graph_adaptor_demo < dimacs_max_flow_file
28// Modified to eat lemon graph format!
29
30
31#include <iostream>
32#include <fstream>
33
34#include <lemon/smart_graph.h>
35#include <lemon/dijkstra.h>
36#include <lemon/maps.h>
37#include <lemon/graph_adaptor.h>
38#include <lemon/dimacs.h>
39#include <lemon/preflow.h>
40#include <tight_edge_filter_map.h>
41
42#include <lemon/graph_reader.h>
43
44
45using namespace lemon;
46
47using std::cout;
48using std::endl;
49
50int main(int argc, char *argv[])
51{
52  if(argc<2)
53  {
54      std::cerr << "USAGE: sub_graph_adaptor_demo input_file.lgf" << std::endl;
55      std::cerr << "The file 'input_file.lgf' has to contain a max flow "
56                << "instance in \n LEMON format "
57                << "(e.g. sub_gad_input.lgf is such a file)."
58                << std::endl;
59      return 0;
60  }
61
62
63  //input stream to read the graph from
64  std::ifstream is(argv[1]);
65
66  typedef SmartGraph Graph;
67
68  typedef Graph::Edge Edge;
69  typedef Graph::Node Node;
70  typedef Graph::EdgeIt EdgeIt;
71  typedef Graph::NodeIt NodeIt;
72  typedef Graph::EdgeMap<int> LengthMap;
73
74  Graph g;
75  Node s, t;
76  LengthMap length(g);
77
78  //readDimacs(is, g, length, s, t);
79
80
81  GraphReader<SmartGraph> reader(is,g);
82  reader.readNode("source",s).readNode("target",t)
83    .readEdgeMap("length",length).run();
84
85  cout << "edges with lengths (of form id, source--length->target): " << endl;
86  for(EdgeIt e(g); e!=INVALID; ++e)
87    cout << " " << g.id(e) << ", " << g.id(g.source(e)) << "--"
88         << length[e] << "->" << g.id(g.target(e)) << endl;
89
90  cout << "s: " << g.id(s) << " t: " << g.id(t) << endl;
91
92  typedef Dijkstra<Graph, LengthMap> Dijkstra;
93  Dijkstra dijkstra(g, length);
94  dijkstra.run(s);
95
96  // This map returns true exactly for those edges which are
97  // tight w.r.t the length funcion and the potential
98  // given by the dijkstra algorithm.
99  typedef TightEdgeFilterMap<Graph, const Dijkstra::DistMap, LengthMap>
100    TightEdgeFilter;
101  TightEdgeFilter tight_edge_filter(g, dijkstra.distMap(), length);
102
103//  ConstMap<Node, bool> const_true_map(true);
104  // This graph contains exaclty the tight edges.
105// typedef SubGraphAdaptor<Graph, ConstMap<Node, bool>, TightEdgeFilter> SubGW;
106  typedef EdgeSubGraphAdaptor<Graph, TightEdgeFilter> SubGW;
107  SubGW gw(g, tight_edge_filter);
108
109  ConstMap<Edge, int> const_1_map(1);
110  Graph::EdgeMap<int> flow(g, 0);
111  // Max flow between s and t in the graph of tight edges.
112  Preflow<SubGW, int, ConstMap<Edge, int>, Graph::EdgeMap<int> >
113    preflow(gw, s, t, const_1_map, flow);
114  preflow.run();
115
116  cout << "maximum number of edge-disjoint shortest paths: "
117       << preflow.flowValue() << endl;
118  cout << "edges of the maximum number of edge-disjoint shortest s-t paths: "
119       << endl;
120  for(EdgeIt e(g); e!=INVALID; ++e)
121    if (flow[e])
122      cout << " " << g.id(e) << ", "
123           << g.id(g.source(e)) << "--"
124           << length[e] << "->" << g.id(g.target(e)) << endl;
125}
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