COIN-OR::LEMON - Graph Library

source: lemon/test/bellman_ford_test.cc @ 1337:4add05447ca0

Last change on this file since 1337:4add05447ca0 was 1337:4add05447ca0, checked in by Alpar Juttner <alpar@…>, 5 years ago

Tests and bugfixes for the STL style iterators (#325)

File size: 7.5 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) 2003-2013
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    for (auto n: const_bf_test.activeNodes()) { ::lemon::ignore_unused_variable_warning(n); }
105    for (Digraph::Node n: const_bf_test.activeNodes()) {
106      ::lemon::ignore_unused_variable_warning(n);
107    }
108  }
109  {
110    BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
111      ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
112      ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
113      ::Create bf_test(gr,length);
114
115    LengthMap length_map;
116    concepts::ReadWriteMap<Node,Arc> pred_map;
117    concepts::ReadWriteMap<Node,Value> dist_map;
118
119    bf_test
120      .lengthMap(length_map)
121      .predMap(pred_map)
122      .distMap(dist_map);
123
124    bf_test.run(s);
125    bf_test.run(s,k);
126
127    bf_test.init();
128    bf_test.addSource(s);
129    bf_test.addSource(s, 1);
130    b = bf_test.processNextRound();
131    b = bf_test.processNextWeakRound();
132
133    bf_test.start();
134    bf_test.checkedStart();
135    bf_test.limitedStart(k);
136
137    l  = bf_test.dist(t);
138    e  = bf_test.predArc(t);
139    s  = bf_test.predNode(t);
140    b  = bf_test.reached(t);
141    pp = bf_test.path(t);
142    pp = bf_test.negativeCycle();
143  }
144}
145
146void checkBellmanFordFunctionCompile()
147{
148  typedef int Value;
149  typedef concepts::Digraph Digraph;
150  typedef Digraph::Arc Arc;
151  typedef Digraph::Node Node;
152  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
153
154  Digraph g;
155  bool b;
156  ::lemon::ignore_unused_variable_warning(b);
157
158  bellmanFord(g,LengthMap()).run(Node());
159  b = bellmanFord(g,LengthMap()).run(Node(),Node());
160  bellmanFord(g,LengthMap())
161    .predMap(concepts::ReadWriteMap<Node,Arc>())
162    .distMap(concepts::ReadWriteMap<Node,Value>())
163    .run(Node());
164  b=bellmanFord(g,LengthMap())
165    .predMap(concepts::ReadWriteMap<Node,Arc>())
166    .distMap(concepts::ReadWriteMap<Node,Value>())
167    .path(concepts::Path<Digraph>())
168    .dist(Value())
169    .run(Node(),Node());
170}
171
172
173template <typename Digraph, typename Value>
174void checkBellmanFord() {
175  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
176  typedef typename Digraph::template ArcMap<Value> LengthMap;
177
178  Digraph gr;
179  Node s, t;
180  LengthMap length(gr);
181
182  std::istringstream input(test_lgf);
183  digraphReader(gr, input).
184    arcMap("length", length).
185    node("source", s).
186    node("target", t).
187    run();
188
189  BellmanFord<Digraph, LengthMap>
190    bf(gr, length);
191  bf.run(s);
192  Path<Digraph> p = bf.path(t);
193
194  check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");
195  check(p.length() == 3, "path() found a wrong path.");
196  check(checkPath(gr, p), "path() found a wrong path.");
197  check(pathSource(gr, p) == s, "path() found a wrong path.");
198  check(pathTarget(gr, p) == t, "path() found a wrong path.");
199
200  ListPath<Digraph> path;
201  Value dist = 0;
202  bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);
203
204  check(reached && dist == -1, "Bellman-Ford found a wrong path.");
205  check(path.length() == 3, "path() found a wrong path.");
206  check(checkPath(gr, path), "path() found a wrong path.");
207  check(pathSource(gr, path) == s, "path() found a wrong path.");
208  check(pathTarget(gr, path) == t, "path() found a wrong path.");
209
210  for(ArcIt e(gr); e!=INVALID; ++e) {
211    Node u=gr.source(e);
212    Node v=gr.target(e);
213    check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),
214          "Wrong output. dist(target)-dist(source)-arc_length=" <<
215          bf.dist(v) - bf.dist(u) - length[e]);
216  }
217
218  for(NodeIt v(gr); v!=INVALID; ++v) {
219    if (bf.reached(v)) {
220      check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");
221      if (bf.predArc(v)!=INVALID ) {
222        Arc e=bf.predArc(v);
223        Node u=gr.source(e);
224        check(u==bf.predNode(v),"Wrong tree.");
225        check(bf.dist(v) - bf.dist(u) == length[e],
226              "Wrong distance! Difference: " <<
227              bf.dist(v) - bf.dist(u) - length[e]);
228      }
229    }
230  }
231}
232
233void checkBellmanFordNegativeCycle() {
234  DIGRAPH_TYPEDEFS(SmartDigraph);
235
236  SmartDigraph gr;
237  IntArcMap length(gr);
238
239  Node n1 = gr.addNode();
240  Node n2 = gr.addNode();
241  Node n3 = gr.addNode();
242  Node n4 = gr.addNode();
243
244  Arc a1 = gr.addArc(n1, n2);
245  Arc a2 = gr.addArc(n2, n2);
246
247  length[a1] = 2;
248  length[a2] = -1;
249
250  {
251    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
252    bf.run(n1);
253    StaticPath<SmartDigraph> p = bf.negativeCycle();
254    check(p.length() == 1 && p.front() == p.back() && p.front() == a2,
255          "Wrong negative cycle.");
256  }
257
258  length[a2] = 0;
259
260  {
261    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
262    bf.run(n1);
263    check(bf.negativeCycle().empty(),
264          "Negative cycle should not be found.");
265  }
266
267  length[gr.addArc(n1, n3)] = 5;
268  length[gr.addArc(n4, n3)] = 1;
269  length[gr.addArc(n2, n4)] = 2;
270  length[gr.addArc(n3, n2)] = -4;
271
272  {
273    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
274    bf.init();
275    bf.addSource(n1);
276    for (int i = 0; i < 4; ++i) {
277      check(bf.negativeCycle().empty(),
278            "Negative cycle should not be found.");
279      bf.processNextRound();
280    }
281    StaticPath<SmartDigraph> p = bf.negativeCycle();
282    check(p.length() == 3, "Wrong negative cycle.");
283    check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,
284          "Wrong negative cycle.");
285  }
286}
287
288int main() {
289  checkBellmanFord<ListDigraph, int>();
290  checkBellmanFord<SmartDigraph, double>();
291  checkBellmanFordNegativeCycle();
292  return 0;
293}
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