COIN-OR::LEMON - Graph Library

source: lemon/test/bellman_ford_test.cc @ 1260:a337a0dd3f75

Last change on this file since 1260:a337a0dd3f75 was 1260:a337a0dd3f75, checked in by Alpar Juttner <alpar@…>, 6 years ago

Further ignore_unused_variable_warning() explicit namespaces (#294)

File size: 7.3 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) 2003-2010
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 <lemon/concepts/digraph.h>
20#include <lemon/smart_graph.h>
21#include <lemon/list_graph.h>
22#include <lemon/lgf_reader.h>
23#include <lemon/bellman_ford.h>
24#include <lemon/path.h>
25
26#include "graph_test.h"
27#include "test_tools.h"
28
29using namespace lemon;
30
31char test_lgf[] =
32  "@nodes\n"
33  "label\n"
34  "0\n"
35  "1\n"
36  "2\n"
37  "3\n"
38  "4\n"
39  "@arcs\n"
40  "    length\n"
41  "0 1 3\n"
42  "1 2 -3\n"
43  "1 2 -5\n"
44  "1 3 -2\n"
45  "0 2 -1\n"
46  "1 2 -4\n"
47  "0 3 2\n"
48  "4 2 -5\n"
49  "2 3 1\n"
50  "@attributes\n"
51  "source 0\n"
52  "target 3\n";
53
54
55void checkBellmanFordCompile()
56{
57  typedef int Value;
58  typedef concepts::Digraph Digraph;
59  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
60  typedef BellmanFord<Digraph, LengthMap> BF;
61  typedef Digraph::Node Node;
62  typedef Digraph::Arc Arc;
63
64  Digraph gr;
65  Node s, t, n;
66  Arc e;
67  Value l;
68  ::lemon::ignore_unused_variable_warning(l);
69  int k=3;
70  bool b;
71  ::lemon::ignore_unused_variable_warning(b);
72  BF::DistMap d(gr);
73  BF::PredMap p(gr);
74  LengthMap length;
75  concepts::Path<Digraph> pp;
76
77  {
78    BF bf_test(gr,length);
79    const BF& const_bf_test = bf_test;
80
81    bf_test.run(s);
82    bf_test.run(s,k);
83
84    bf_test.init();
85    bf_test.addSource(s);
86    bf_test.addSource(s, 1);
87    b = bf_test.processNextRound();
88    b = bf_test.processNextWeakRound();
89
90    bf_test.start();
91    bf_test.checkedStart();
92    bf_test.limitedStart(k);
93
94    l  = const_bf_test.dist(t);
95    e  = const_bf_test.predArc(t);
96    s  = const_bf_test.predNode(t);
97    b  = const_bf_test.reached(t);
98    d  = const_bf_test.distMap();
99    p  = const_bf_test.predMap();
100    pp = const_bf_test.path(t);
101    pp = const_bf_test.negativeCycle();
102
103    for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {}
104  }
105  {
106    BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
107      ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
108      ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
109      ::Create bf_test(gr,length);
110
111    LengthMap length_map;
112    concepts::ReadWriteMap<Node,Arc> pred_map;
113    concepts::ReadWriteMap<Node,Value> dist_map;
114
115    bf_test
116      .lengthMap(length_map)
117      .predMap(pred_map)
118      .distMap(dist_map);
119
120    bf_test.run(s);
121    bf_test.run(s,k);
122
123    bf_test.init();
124    bf_test.addSource(s);
125    bf_test.addSource(s, 1);
126    b = bf_test.processNextRound();
127    b = bf_test.processNextWeakRound();
128
129    bf_test.start();
130    bf_test.checkedStart();
131    bf_test.limitedStart(k);
132
133    l  = bf_test.dist(t);
134    e  = bf_test.predArc(t);
135    s  = bf_test.predNode(t);
136    b  = bf_test.reached(t);
137    pp = bf_test.path(t);
138    pp = bf_test.negativeCycle();
139  }
140}
141
142void checkBellmanFordFunctionCompile()
143{
144  typedef int Value;
145  typedef concepts::Digraph Digraph;
146  typedef Digraph::Arc Arc;
147  typedef Digraph::Node Node;
148  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
149
150  Digraph g;
151  bool b;
152  ::lemon::ignore_unused_variable_warning(b);
153
154  bellmanFord(g,LengthMap()).run(Node());
155  b = bellmanFord(g,LengthMap()).run(Node(),Node());
156  bellmanFord(g,LengthMap())
157    .predMap(concepts::ReadWriteMap<Node,Arc>())
158    .distMap(concepts::ReadWriteMap<Node,Value>())
159    .run(Node());
160  b=bellmanFord(g,LengthMap())
161    .predMap(concepts::ReadWriteMap<Node,Arc>())
162    .distMap(concepts::ReadWriteMap<Node,Value>())
163    .path(concepts::Path<Digraph>())
164    .dist(Value())
165    .run(Node(),Node());
166}
167
168
169template <typename Digraph, typename Value>
170void checkBellmanFord() {
171  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
172  typedef typename Digraph::template ArcMap<Value> LengthMap;
173
174  Digraph gr;
175  Node s, t;
176  LengthMap length(gr);
177
178  std::istringstream input(test_lgf);
179  digraphReader(gr, input).
180    arcMap("length", length).
181    node("source", s).
182    node("target", t).
183    run();
184
185  BellmanFord<Digraph, LengthMap>
186    bf(gr, length);
187  bf.run(s);
188  Path<Digraph> p = bf.path(t);
189
190  check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");
191  check(p.length() == 3, "path() found a wrong path.");
192  check(checkPath(gr, p), "path() found a wrong path.");
193  check(pathSource(gr, p) == s, "path() found a wrong path.");
194  check(pathTarget(gr, p) == t, "path() found a wrong path.");
195
196  ListPath<Digraph> path;
197  Value dist = 0;
198  bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);
199
200  check(reached && dist == -1, "Bellman-Ford found a wrong path.");
201  check(path.length() == 3, "path() found a wrong path.");
202  check(checkPath(gr, path), "path() found a wrong path.");
203  check(pathSource(gr, path) == s, "path() found a wrong path.");
204  check(pathTarget(gr, path) == t, "path() found a wrong path.");
205
206  for(ArcIt e(gr); e!=INVALID; ++e) {
207    Node u=gr.source(e);
208    Node v=gr.target(e);
209    check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),
210          "Wrong output. dist(target)-dist(source)-arc_length=" <<
211          bf.dist(v) - bf.dist(u) - length[e]);
212  }
213
214  for(NodeIt v(gr); v!=INVALID; ++v) {
215    if (bf.reached(v)) {
216      check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");
217      if (bf.predArc(v)!=INVALID ) {
218        Arc e=bf.predArc(v);
219        Node u=gr.source(e);
220        check(u==bf.predNode(v),"Wrong tree.");
221        check(bf.dist(v) - bf.dist(u) == length[e],
222              "Wrong distance! Difference: " <<
223              bf.dist(v) - bf.dist(u) - length[e]);
224      }
225    }
226  }
227}
228
229void checkBellmanFordNegativeCycle() {
230  DIGRAPH_TYPEDEFS(SmartDigraph);
231
232  SmartDigraph gr;
233  IntArcMap length(gr);
234
235  Node n1 = gr.addNode();
236  Node n2 = gr.addNode();
237  Node n3 = gr.addNode();
238  Node n4 = gr.addNode();
239
240  Arc a1 = gr.addArc(n1, n2);
241  Arc a2 = gr.addArc(n2, n2);
242
243  length[a1] = 2;
244  length[a2] = -1;
245
246  {
247    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
248    bf.run(n1);
249    StaticPath<SmartDigraph> p = bf.negativeCycle();
250    check(p.length() == 1 && p.front() == p.back() && p.front() == a2,
251          "Wrong negative cycle.");
252  }
253
254  length[a2] = 0;
255
256  {
257    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
258    bf.run(n1);
259    check(bf.negativeCycle().empty(),
260          "Negative cycle should not be found.");
261  }
262
263  length[gr.addArc(n1, n3)] = 5;
264  length[gr.addArc(n4, n3)] = 1;
265  length[gr.addArc(n2, n4)] = 2;
266  length[gr.addArc(n3, n2)] = -4;
267
268  {
269    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
270    bf.init();
271    bf.addSource(n1);
272    for (int i = 0; i < 4; ++i) {
273      check(bf.negativeCycle().empty(),
274            "Negative cycle should not be found.");
275      bf.processNextRound();
276    }
277    StaticPath<SmartDigraph> p = bf.negativeCycle();
278    check(p.length() == 3, "Wrong negative cycle.");
279    check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,
280          "Wrong negative cycle.");
281  }
282}
283
284int main() {
285  checkBellmanFord<ListDigraph, int>();
286  checkBellmanFord<SmartDigraph, double>();
287  checkBellmanFordNegativeCycle();
288  return 0;
289}
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