test/bellman_ford_test.cc
author Peter Kovacs <kpeter@inf.elte.hu>
Thu, 12 Nov 2009 23:45:15 +0100
changeset 811 fe80a8145653
parent 781 6f10c6ec5a21
parent 790 1870cfd14fb6
child 844 a6eb9698c321
permissions -rw-r--r--
Small implementation improvements in MCF algorithms (#180)

- Handle max() as infinite value (not only infinity()).
- Better GEQ handling in CapacityScaling.
- Skip the unnecessary saturating operations in the first phase in
CapacityScaling.
- Use vector<char> instead of vector<bool> and vector<int> if it is
possible and it proved to be usually faster.
kpeter@698
     1
/* -*- mode: C++; indent-tabs-mode: nil; -*-
kpeter@698
     2
 *
kpeter@698
     3
 * This file is a part of LEMON, a generic C++ optimization library.
kpeter@698
     4
 *
kpeter@698
     5
 * Copyright (C) 2003-2009
kpeter@698
     6
 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
kpeter@698
     7
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
kpeter@698
     8
 *
kpeter@698
     9
 * Permission to use, modify and distribute this software is granted
kpeter@698
    10
 * provided that this copyright notice appears in all copies. For
kpeter@698
    11
 * precise terms see the accompanying LICENSE file.
kpeter@698
    12
 *
kpeter@698
    13
 * This software is provided "AS IS" with no warranty of any kind,
kpeter@698
    14
 * express or implied, and with no claim as to its suitability for any
kpeter@698
    15
 * purpose.
kpeter@698
    16
 *
kpeter@698
    17
 */
kpeter@698
    18
kpeter@698
    19
#include <lemon/concepts/digraph.h>
kpeter@698
    20
#include <lemon/smart_graph.h>
kpeter@698
    21
#include <lemon/list_graph.h>
kpeter@698
    22
#include <lemon/lgf_reader.h>
kpeter@698
    23
#include <lemon/bellman_ford.h>
kpeter@698
    24
#include <lemon/path.h>
kpeter@698
    25
kpeter@698
    26
#include "graph_test.h"
kpeter@698
    27
#include "test_tools.h"
kpeter@698
    28
kpeter@698
    29
using namespace lemon;
kpeter@698
    30
kpeter@698
    31
char test_lgf[] =
kpeter@698
    32
  "@nodes\n"
kpeter@698
    33
  "label\n"
kpeter@698
    34
  "0\n"
kpeter@698
    35
  "1\n"
kpeter@698
    36
  "2\n"
kpeter@698
    37
  "3\n"
kpeter@698
    38
  "4\n"
kpeter@698
    39
  "@arcs\n"
kpeter@698
    40
  "    length\n"
kpeter@698
    41
  "0 1 3\n"
kpeter@698
    42
  "1 2 -3\n"
kpeter@698
    43
  "1 2 -5\n"
kpeter@698
    44
  "1 3 -2\n"
kpeter@698
    45
  "0 2 -1\n"
kpeter@698
    46
  "1 2 -4\n"
kpeter@698
    47
  "0 3 2\n"
kpeter@698
    48
  "4 2 -5\n"
kpeter@698
    49
  "2 3 1\n"
kpeter@698
    50
  "@attributes\n"
kpeter@698
    51
  "source 0\n"
kpeter@698
    52
  "target 3\n";
kpeter@698
    53
kpeter@698
    54
kpeter@698
    55
void checkBellmanFordCompile()
kpeter@698
    56
{
kpeter@698
    57
  typedef int Value;
kpeter@698
    58
  typedef concepts::Digraph Digraph;
kpeter@698
    59
  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
kpeter@698
    60
  typedef BellmanFord<Digraph, LengthMap> BF;
kpeter@698
    61
  typedef Digraph::Node Node;
kpeter@698
    62
  typedef Digraph::Arc Arc;
kpeter@698
    63
kpeter@698
    64
  Digraph gr;
kpeter@698
    65
  Node s, t, n;
kpeter@698
    66
  Arc e;
kpeter@698
    67
  Value l;
alpar@790
    68
  int k=3;
kpeter@698
    69
  bool b;
kpeter@698
    70
  BF::DistMap d(gr);
kpeter@698
    71
  BF::PredMap p(gr);
kpeter@698
    72
  LengthMap length;
kpeter@698
    73
  concepts::Path<Digraph> pp;
kpeter@698
    74
kpeter@698
    75
  {
kpeter@698
    76
    BF bf_test(gr,length);
kpeter@698
    77
    const BF& const_bf_test = bf_test;
kpeter@698
    78
kpeter@698
    79
    bf_test.run(s);
kpeter@698
    80
    bf_test.run(s,k);
kpeter@698
    81
kpeter@698
    82
    bf_test.init();
kpeter@698
    83
    bf_test.addSource(s);
kpeter@698
    84
    bf_test.addSource(s, 1);
kpeter@698
    85
    b = bf_test.processNextRound();
kpeter@698
    86
    b = bf_test.processNextWeakRound();
kpeter@698
    87
kpeter@698
    88
    bf_test.start();
kpeter@698
    89
    bf_test.checkedStart();
kpeter@698
    90
    bf_test.limitedStart(k);
kpeter@698
    91
kpeter@698
    92
    l  = const_bf_test.dist(t);
kpeter@698
    93
    e  = const_bf_test.predArc(t);
kpeter@698
    94
    s  = const_bf_test.predNode(t);
kpeter@698
    95
    b  = const_bf_test.reached(t);
kpeter@698
    96
    d  = const_bf_test.distMap();
kpeter@698
    97
    p  = const_bf_test.predMap();
kpeter@698
    98
    pp = const_bf_test.path(t);
kpeter@781
    99
    pp = const_bf_test.negativeCycle();
kpeter@698
   100
    
kpeter@698
   101
    for (BF::ActiveIt it(const_bf_test); it != INVALID; ++it) {}
kpeter@698
   102
  }
kpeter@698
   103
  {
kpeter@698
   104
    BF::SetPredMap<concepts::ReadWriteMap<Node,Arc> >
kpeter@698
   105
      ::SetDistMap<concepts::ReadWriteMap<Node,Value> >
kpeter@698
   106
      ::SetOperationTraits<BellmanFordDefaultOperationTraits<Value> >
kpeter@698
   107
      ::Create bf_test(gr,length);
kpeter@698
   108
kpeter@698
   109
    LengthMap length_map;
kpeter@698
   110
    concepts::ReadWriteMap<Node,Arc> pred_map;
kpeter@698
   111
    concepts::ReadWriteMap<Node,Value> dist_map;
kpeter@698
   112
    
kpeter@698
   113
    bf_test
kpeter@698
   114
      .lengthMap(length_map)
kpeter@698
   115
      .predMap(pred_map)
kpeter@698
   116
      .distMap(dist_map);
kpeter@698
   117
kpeter@698
   118
    bf_test.run(s);
kpeter@698
   119
    bf_test.run(s,k);
kpeter@698
   120
kpeter@698
   121
    bf_test.init();
kpeter@698
   122
    bf_test.addSource(s);
kpeter@698
   123
    bf_test.addSource(s, 1);
kpeter@698
   124
    b = bf_test.processNextRound();
kpeter@698
   125
    b = bf_test.processNextWeakRound();
kpeter@698
   126
kpeter@698
   127
    bf_test.start();
kpeter@698
   128
    bf_test.checkedStart();
kpeter@698
   129
    bf_test.limitedStart(k);
kpeter@698
   130
kpeter@698
   131
    l  = bf_test.dist(t);
kpeter@698
   132
    e  = bf_test.predArc(t);
kpeter@698
   133
    s  = bf_test.predNode(t);
kpeter@698
   134
    b  = bf_test.reached(t);
kpeter@698
   135
    pp = bf_test.path(t);
kpeter@781
   136
    pp = bf_test.negativeCycle();
kpeter@698
   137
  }
kpeter@698
   138
}
kpeter@698
   139
kpeter@698
   140
void checkBellmanFordFunctionCompile()
kpeter@698
   141
{
kpeter@698
   142
  typedef int Value;
kpeter@698
   143
  typedef concepts::Digraph Digraph;
kpeter@698
   144
  typedef Digraph::Arc Arc;
kpeter@698
   145
  typedef Digraph::Node Node;
kpeter@698
   146
  typedef concepts::ReadMap<Digraph::Arc,Value> LengthMap;
kpeter@698
   147
kpeter@698
   148
  Digraph g;
kpeter@698
   149
  bool b;
kpeter@698
   150
  bellmanFord(g,LengthMap()).run(Node());
kpeter@698
   151
  b = bellmanFord(g,LengthMap()).run(Node(),Node());
kpeter@698
   152
  bellmanFord(g,LengthMap())
kpeter@698
   153
    .predMap(concepts::ReadWriteMap<Node,Arc>())
kpeter@698
   154
    .distMap(concepts::ReadWriteMap<Node,Value>())
kpeter@698
   155
    .run(Node());
kpeter@698
   156
  b=bellmanFord(g,LengthMap())
kpeter@698
   157
    .predMap(concepts::ReadWriteMap<Node,Arc>())
kpeter@698
   158
    .distMap(concepts::ReadWriteMap<Node,Value>())
kpeter@698
   159
    .path(concepts::Path<Digraph>())
kpeter@698
   160
    .dist(Value())
kpeter@698
   161
    .run(Node(),Node());
kpeter@698
   162
}
kpeter@698
   163
kpeter@698
   164
kpeter@698
   165
template <typename Digraph, typename Value>
kpeter@698
   166
void checkBellmanFord() {
kpeter@698
   167
  TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
kpeter@698
   168
  typedef typename Digraph::template ArcMap<Value> LengthMap;
kpeter@698
   169
kpeter@698
   170
  Digraph gr;
kpeter@698
   171
  Node s, t;
kpeter@698
   172
  LengthMap length(gr);
kpeter@698
   173
kpeter@698
   174
  std::istringstream input(test_lgf);
kpeter@698
   175
  digraphReader(gr, input).
kpeter@698
   176
    arcMap("length", length).
kpeter@698
   177
    node("source", s).
kpeter@698
   178
    node("target", t).
kpeter@698
   179
    run();
kpeter@698
   180
kpeter@698
   181
  BellmanFord<Digraph, LengthMap>
kpeter@698
   182
    bf(gr, length);
kpeter@698
   183
  bf.run(s);
kpeter@698
   184
  Path<Digraph> p = bf.path(t);
kpeter@698
   185
kpeter@698
   186
  check(bf.reached(t) && bf.dist(t) == -1, "Bellman-Ford found a wrong path.");
kpeter@698
   187
  check(p.length() == 3, "path() found a wrong path.");
kpeter@698
   188
  check(checkPath(gr, p), "path() found a wrong path.");
kpeter@698
   189
  check(pathSource(gr, p) == s, "path() found a wrong path.");
kpeter@698
   190
  check(pathTarget(gr, p) == t, "path() found a wrong path.");
kpeter@698
   191
  
kpeter@698
   192
  ListPath<Digraph> path;
kpeter@698
   193
  Value dist;
kpeter@698
   194
  bool reached = bellmanFord(gr,length).path(path).dist(dist).run(s,t);
kpeter@698
   195
kpeter@698
   196
  check(reached && dist == -1, "Bellman-Ford found a wrong path.");
kpeter@698
   197
  check(path.length() == 3, "path() found a wrong path.");
kpeter@698
   198
  check(checkPath(gr, path), "path() found a wrong path.");
kpeter@698
   199
  check(pathSource(gr, path) == s, "path() found a wrong path.");
kpeter@698
   200
  check(pathTarget(gr, path) == t, "path() found a wrong path.");
kpeter@698
   201
kpeter@698
   202
  for(ArcIt e(gr); e!=INVALID; ++e) {
kpeter@698
   203
    Node u=gr.source(e);
kpeter@698
   204
    Node v=gr.target(e);
kpeter@698
   205
    check(!bf.reached(u) || (bf.dist(v) - bf.dist(u) <= length[e]),
kpeter@698
   206
          "Wrong output. dist(target)-dist(source)-arc_length=" <<
kpeter@698
   207
          bf.dist(v) - bf.dist(u) - length[e]);
kpeter@698
   208
  }
kpeter@698
   209
kpeter@698
   210
  for(NodeIt v(gr); v!=INVALID; ++v) {
kpeter@698
   211
    if (bf.reached(v)) {
kpeter@698
   212
      check(v==s || bf.predArc(v)!=INVALID, "Wrong tree.");
kpeter@698
   213
      if (bf.predArc(v)!=INVALID ) {
kpeter@698
   214
        Arc e=bf.predArc(v);
kpeter@698
   215
        Node u=gr.source(e);
kpeter@698
   216
        check(u==bf.predNode(v),"Wrong tree.");
kpeter@698
   217
        check(bf.dist(v) - bf.dist(u) == length[e],
kpeter@698
   218
              "Wrong distance! Difference: " <<
kpeter@698
   219
              bf.dist(v) - bf.dist(u) - length[e]);
kpeter@698
   220
      }
kpeter@698
   221
    }
kpeter@698
   222
  }
kpeter@698
   223
}
kpeter@698
   224
kpeter@699
   225
void checkBellmanFordNegativeCycle() {
kpeter@699
   226
  DIGRAPH_TYPEDEFS(SmartDigraph);
kpeter@699
   227
kpeter@699
   228
  SmartDigraph gr;
kpeter@699
   229
  IntArcMap length(gr);
kpeter@699
   230
  
kpeter@699
   231
  Node n1 = gr.addNode();
kpeter@699
   232
  Node n2 = gr.addNode();
kpeter@699
   233
  Node n3 = gr.addNode();
kpeter@699
   234
  Node n4 = gr.addNode();
kpeter@699
   235
  
kpeter@699
   236
  Arc a1 = gr.addArc(n1, n2);
kpeter@699
   237
  Arc a2 = gr.addArc(n2, n2);
kpeter@699
   238
  
kpeter@699
   239
  length[a1] = 2;
kpeter@699
   240
  length[a2] = -1;
kpeter@699
   241
  
kpeter@699
   242
  {
kpeter@699
   243
    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
kpeter@699
   244
    bf.run(n1);
kpeter@699
   245
    StaticPath<SmartDigraph> p = bf.negativeCycle();
kpeter@699
   246
    check(p.length() == 1 && p.front() == p.back() && p.front() == a2,
kpeter@699
   247
          "Wrong negative cycle.");
kpeter@699
   248
  }
kpeter@699
   249
 
kpeter@699
   250
  length[a2] = 0;
kpeter@699
   251
  
kpeter@699
   252
  {
kpeter@699
   253
    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
kpeter@699
   254
    bf.run(n1);
kpeter@699
   255
    check(bf.negativeCycle().empty(),
kpeter@699
   256
          "Negative cycle should not be found.");
kpeter@699
   257
  }
kpeter@699
   258
  
kpeter@699
   259
  length[gr.addArc(n1, n3)] = 5;
kpeter@699
   260
  length[gr.addArc(n4, n3)] = 1;
kpeter@699
   261
  length[gr.addArc(n2, n4)] = 2;
kpeter@699
   262
  length[gr.addArc(n3, n2)] = -4;
kpeter@699
   263
  
kpeter@699
   264
  {
kpeter@699
   265
    BellmanFord<SmartDigraph, IntArcMap> bf(gr, length);
kpeter@699
   266
    bf.init();
kpeter@699
   267
    bf.addSource(n1);
kpeter@699
   268
    for (int i = 0; i < 4; ++i) {
kpeter@699
   269
      check(bf.negativeCycle().empty(),
kpeter@699
   270
            "Negative cycle should not be found.");
kpeter@699
   271
      bf.processNextRound();
kpeter@699
   272
    }
kpeter@699
   273
    StaticPath<SmartDigraph> p = bf.negativeCycle();
kpeter@699
   274
    check(p.length() == 3, "Wrong negative cycle.");
kpeter@699
   275
    check(length[p.nth(0)] + length[p.nth(1)] + length[p.nth(2)] == -1,
kpeter@699
   276
          "Wrong negative cycle.");
kpeter@699
   277
  }
kpeter@699
   278
}
kpeter@699
   279
kpeter@698
   280
int main() {
kpeter@698
   281
  checkBellmanFord<ListDigraph, int>();
kpeter@698
   282
  checkBellmanFord<SmartDigraph, double>();
kpeter@699
   283
  checkBellmanFordNegativeCycle();
kpeter@698
   284
  return 0;
kpeter@698
   285
}