COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/test/preflow_test.cc @ 1222:a3fb216a267d

Last change on this file since 1222:a3fb216a267d was 1222:a3fb216a267d, checked in by Alpar Juttner, 15 years ago

The first step toward function type interface to Preflow alg:

  • Naming changed to be closer in style to the BFD/DFS/Dijkstra triplet.
  • Property exe set to *
File size: 4.9 KB
Line 
1/* -*- C++ -*-
2 * src/test/preflow_test.cc - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#include <fstream>
18#include <string>
19
20#include "test_tools.h"
21#include <lemon/smart_graph.h>
22#include <lemon/dimacs.h>
23#include <lemon/preflow.h>
24#include <lemon/concept/graph.h>
25#include <lemon/concept/maps.h>
26
27using namespace lemon;
28
29void check_Preflow()
30{
31  typedef int VType;
32  typedef concept::StaticGraph Graph;
33
34  typedef Graph::Node Node;
35  typedef Graph::Edge Edge;
36  typedef concept::ReadMap<Edge,VType> CapMap;
37  typedef concept::ReadWriteMap<Edge,VType> FlowMap;
38  typedef concept::ReadWriteMap<Node,bool> CutMap;
39 
40  typedef Preflow<Graph, int, CapMap, FlowMap> PType;
41
42  Graph g;
43  Node n;
44  CapMap cap;
45  FlowMap flow;
46  CutMap cut;
47
48  PType preflow_test(g,n,n,cap,flow);
49
50  preflow_test.run();
51  preflow_test.flowValue();
52  preflow_test.source(n);
53  preflow_test.flowMap(flow);
54
55  preflow_test.phase1(PType::NO_FLOW);
56  preflow_test.minCut(cut);
57
58  preflow_test.phase2();
59  preflow_test.target(n);
60  preflow_test.capacityMap(cap);
61  preflow_test.minMinCut(cut);
62  preflow_test.maxMinCut(cut);
63}
64
65int cut_value ( SmartGraph& g, SmartGraph::NodeMap<bool>& cut,
66                SmartGraph::EdgeMap<int>& cap) {
67 
68  int c=0;
69  for(SmartGraph::EdgeIt e(g); e!=INVALID; ++e) {
70    if (cut[g.source(e)] && !cut[g.target(e)]) c+=cap[e];
71  }
72  return c;
73}
74
75int main() {
76
77  typedef SmartGraph Graph;
78 
79  typedef Graph::Node Node;
80  typedef Graph::NodeIt NodeIt;
81  typedef Graph::EdgeIt EdgeIt;
82  typedef Graph::EdgeMap<int> CapMap;
83  typedef Graph::EdgeMap<int> FlowMap;
84  typedef Graph::NodeMap<bool> CutMap;
85
86  typedef Preflow<Graph, int> PType;
87
88  std::string f_name;
89  if( getenv("srcdir") )
90    f_name = std::string(getenv("srcdir"));
91  else f_name = ".";
92  f_name += "/preflow_graph.dim";
93 
94  std::ifstream file(f_name.c_str());
95 
96  check(file, "Input file '" << f_name << "' not found.");
97 
98  Graph g;
99  Node s, t;
100  CapMap cap(g);
101  readDimacs(file, g, cap, s, t);
102
103  FlowMap flow(g,0);
104
105 
106
107  PType preflow_test(g, s, t, cap, flow);
108  preflow_test.run(PType::ZERO_FLOW);
109   
110  CutMap min_cut(g,false);
111  preflow_test.minCut(min_cut);
112  int min_cut_value=cut_value(g,min_cut,cap);
113   
114  CutMap min_min_cut(g,false);
115  preflow_test.minMinCut(min_min_cut);
116  int min_min_cut_value=cut_value(g,min_min_cut,cap);
117   
118  CutMap max_min_cut(g,false);
119  preflow_test.maxMinCut(max_min_cut);
120  int max_min_cut_value=cut_value(g,max_min_cut,cap);
121
122  check(preflow_test.flowValue() == min_cut_value &&
123        min_cut_value == min_min_cut_value &&
124        min_min_cut_value == max_min_cut_value,
125        "The max flow value is not equal to the three min cut values.");
126
127  int flow_value=preflow_test.flowValue();
128
129
130
131  for(EdgeIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e];
132  preflow_test.capacityMap(cap); 
133
134  preflow_test.phase1(PType::PRE_FLOW);
135
136  CutMap min_cut1(g,false);
137  preflow_test.minCut(min_cut1);
138  min_cut_value=cut_value(g,min_cut1,cap);
139   
140  check(preflow_test.flowValue() == min_cut_value &&
141        min_cut_value == 2*flow_value,
142        "The max flow value or the min cut value is wrong.");
143
144  preflow_test.phase2();
145
146  CutMap min_cut2(g,false);
147  preflow_test.minCut(min_cut2);
148  min_cut_value=cut_value(g,min_cut2,cap);
149   
150  CutMap min_min_cut2(g,false);
151  preflow_test.minMinCut(min_min_cut2);
152  min_min_cut_value=cut_value(g,min_min_cut2,cap);
153 
154  preflow_test.maxMinCut(max_min_cut);
155  max_min_cut_value=cut_value(g,max_min_cut,cap);
156
157  check(preflow_test.flowValue() == min_cut_value &&
158        min_cut_value == min_min_cut_value &&
159        min_min_cut_value == max_min_cut_value &&
160        min_cut_value == 2*flow_value,
161        "The max flow value or the three min cut values were not doubled");
162
163
164
165  EdgeIt e(g);
166  for( int i=1; i==10; ++i ) {
167    flow.set(e,0);
168    ++e;
169  }
170
171  preflow_test.flowMap(flow);
172
173  NodeIt tmp1(g,s);
174  ++tmp1;
175  if ( tmp1 != INVALID ) s=tmp1;
176
177  NodeIt tmp2(g,t);
178  ++tmp2;
179  if ( tmp2 != INVALID ) t=tmp2;
180
181  preflow_test.source(s);
182  preflow_test.target(t);
183 
184  preflow_test.run();
185
186  CutMap min_cut3(g,false);
187  preflow_test.minCut(min_cut3);
188  min_cut_value=cut_value(g,min_cut3,cap);
189   
190  CutMap min_min_cut3(g,false);
191  preflow_test.minMinCut(min_min_cut3);
192  min_min_cut_value=cut_value(g,min_min_cut3,cap);
193   
194  preflow_test.maxMinCut(max_min_cut);
195  max_min_cut_value=cut_value(g,max_min_cut,cap);
196
197  check(preflow_test.flowValue() == min_cut_value &&
198        min_cut_value == min_min_cut_value &&
199        min_min_cut_value == max_min_cut_value,
200        "The max flow value or the three min cut values are incorrect.");
201}
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