COIN-OR::LEMON - Graph Library

source: lemon/test/suurballe_test.cc @ 927:9a7e4e606f83

Last change on this file since 927:9a7e4e606f83 was 927:9a7e4e606f83, checked in by Peter Kovacs <kpeter@…>, 10 years ago

Add a fullInit() function to Suurballe (#181, #323)
to provide faster handling of multiple targets.
A start() function is also added, just for the sake of
convenience.

File size: 6.4 KB
Line 
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#include <iostream>
20
21#include <lemon/list_graph.h>
22#include <lemon/lgf_reader.h>
23#include <lemon/path.h>
24#include <lemon/suurballe.h>
25#include <lemon/concepts/digraph.h>
26
27#include "test_tools.h"
28
29using namespace lemon;
30
31char test_lgf[] =
32  "@nodes\n"
33  "label\n"
34  "1\n"
35  "2\n"
36  "3\n"
37  "4\n"
38  "5\n"
39  "6\n"
40  "7\n"
41  "8\n"
42  "9\n"
43  "10\n"
44  "11\n"
45  "12\n"
46  "@arcs\n"
47  "      length\n"
48  " 1  2  70\n"
49  " 1  3 150\n"
50  " 1  4  80\n"
51  " 2  8  80\n"
52  " 3  5 140\n"
53  " 4  6  60\n"
54  " 4  7  80\n"
55  " 4  8 110\n"
56  " 5  7  60\n"
57  " 5 11 120\n"
58  " 6  3   0\n"
59  " 6  9 140\n"
60  " 6 10  90\n"
61  " 7  1  30\n"
62  " 8 12  60\n"
63  " 9 12  50\n"
64  "10 12  70\n"
65  "10  2 100\n"
66  "10  7  60\n"
67  "11 10  20\n"
68  "12 11  30\n"
69  "@attributes\n"
70  "source  1\n"
71  "target 12\n"
72  "@end\n";
73
74// Check the interface of Suurballe
75void checkSuurballeCompile()
76{
77  typedef int VType;
78  typedef concepts::Digraph Digraph;
79
80  typedef Digraph::Node Node;
81  typedef Digraph::Arc Arc;
82  typedef concepts::ReadMap<Arc, VType> LengthMap;
83 
84  typedef Suurballe<Digraph, LengthMap> SuurballeType;
85
86  Digraph g;
87  Node n;
88  Arc e;
89  LengthMap len;
90  SuurballeType::FlowMap flow(g);
91  SuurballeType::PotentialMap pi(g);
92
93  SuurballeType suurb_test(g, len);
94  const SuurballeType& const_suurb_test = suurb_test;
95
96  suurb_test
97    .flowMap(flow)
98    .potentialMap(pi);
99
100  int k;
101  k = suurb_test.run(n, n);
102  k = suurb_test.run(n, n, k);
103  suurb_test.init(n);
104  suurb_test.fullInit(n);
105  suurb_test.start(n);
106  suurb_test.start(n, k);
107  k = suurb_test.findFlow(n);
108  k = suurb_test.findFlow(n, k);
109  suurb_test.findPaths();
110 
111  int f;
112  VType c;
113  c = const_suurb_test.totalLength();
114  f = const_suurb_test.flow(e);
115  const SuurballeType::FlowMap& fm =
116    const_suurb_test.flowMap();
117  c = const_suurb_test.potential(n);
118  const SuurballeType::PotentialMap& pm =
119    const_suurb_test.potentialMap();
120  k = const_suurb_test.pathNum();
121  Path<Digraph> p = const_suurb_test.path(k);
122 
123  ignore_unused_variable_warning(fm);
124  ignore_unused_variable_warning(pm);
125}
126
127// Check the feasibility of the flow
128template <typename Digraph, typename FlowMap>
129bool checkFlow( const Digraph& gr, const FlowMap& flow,
130                typename Digraph::Node s, typename Digraph::Node t,
131                int value )
132{
133  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
134  for (ArcIt e(gr); e != INVALID; ++e)
135    if (!(flow[e] == 0 || flow[e] == 1)) return false;
136
137  for (NodeIt n(gr); n != INVALID; ++n) {
138    int sum = 0;
139    for (OutArcIt e(gr, n); e != INVALID; ++e)
140      sum += flow[e];
141    for (InArcIt e(gr, n); e != INVALID; ++e)
142      sum -= flow[e];
143    if (n == s && sum != value) return false;
144    if (n == t && sum != -value) return false;
145    if (n != s && n != t && sum != 0) return false;
146  }
147
148  return true;
149}
150
151// Check the optimalitiy of the flow
152template < typename Digraph, typename CostMap,
153           typename FlowMap, typename PotentialMap >
154bool checkOptimality( const Digraph& gr, const CostMap& cost,
155                      const FlowMap& flow, const PotentialMap& pi )
156{
157  // Check the "Complementary Slackness" optimality condition
158  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
159  bool opt = true;
160  for (ArcIt e(gr); e != INVALID; ++e) {
161    typename CostMap::Value red_cost =
162      cost[e] + pi[gr.source(e)] - pi[gr.target(e)];
163    opt = (flow[e] == 0 && red_cost >= 0) ||
164          (flow[e] == 1 && red_cost <= 0);
165    if (!opt) break;
166  }
167  return opt;
168}
169
170// Check a path
171template <typename Digraph, typename Path>
172bool checkPath( const Digraph& gr, const Path& path,
173                typename Digraph::Node s, typename Digraph::Node t)
174{
175  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
176  Node n = s;
177  for (int i = 0; i < path.length(); ++i) {
178    if (gr.source(path.nth(i)) != n) return false;
179    n = gr.target(path.nth(i));
180  }
181  return n == t;
182}
183
184
185int main()
186{
187  DIGRAPH_TYPEDEFS(ListDigraph);
188
189  // Read the test digraph
190  ListDigraph digraph;
191  ListDigraph::ArcMap<int> length(digraph);
192  Node s, t;
193
194  std::istringstream input(test_lgf);
195  DigraphReader<ListDigraph>(digraph, input).
196    arcMap("length", length).
197    node("source", s).
198    node("target", t).
199    run();
200
201  // Find 2 paths
202  {
203    Suurballe<ListDigraph> suurballe(digraph, length);
204    check(suurballe.run(s, t) == 2, "Wrong number of paths");
205    check(checkFlow(digraph, suurballe.flowMap(), s, t, 2),
206          "The flow is not feasible");
207    check(suurballe.totalLength() == 510, "The flow is not optimal");
208    check(checkOptimality(digraph, length, suurballe.flowMap(),
209                          suurballe.potentialMap()),
210          "Wrong potentials");
211    for (int i = 0; i < suurballe.pathNum(); ++i)
212      check(checkPath(digraph, suurballe.path(i), s, t), "Wrong path");
213  }
214
215  // Find 3 paths
216  {
217    Suurballe<ListDigraph> suurballe(digraph, length);
218    check(suurballe.run(s, t, 3) == 3, "Wrong number of paths");
219    check(checkFlow(digraph, suurballe.flowMap(), s, t, 3),
220          "The flow is not feasible");
221    check(suurballe.totalLength() == 1040, "The flow is not optimal");
222    check(checkOptimality(digraph, length, suurballe.flowMap(),
223                          suurballe.potentialMap()),
224          "Wrong potentials");
225    for (int i = 0; i < suurballe.pathNum(); ++i)
226      check(checkPath(digraph, suurballe.path(i), s, t), "Wrong path");
227  }
228
229  // Find 5 paths (only 3 can be found)
230  {
231    Suurballe<ListDigraph> suurballe(digraph, length);
232    check(suurballe.run(s, t, 5) == 3, "Wrong number of paths");
233    check(checkFlow(digraph, suurballe.flowMap(), s, t, 3),
234          "The flow is not feasible");
235    check(suurballe.totalLength() == 1040, "The flow is not optimal");
236    check(checkOptimality(digraph, length, suurballe.flowMap(),
237                          suurballe.potentialMap()),
238          "Wrong potentials");
239    for (int i = 0; i < suurballe.pathNum(); ++i)
240      check(checkPath(digraph, suurballe.path(i), s, t), "Wrong path");
241  }
242
243  return 0;
244}
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