COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/test/preflow_test.cc @ 985:741f3108a90f

Last change on this file since 985:741f3108a90f was 959:c80ef5912903, checked in by Mihaly Barasz, 15 years ago

skeleton(s) -> concept renaming

  • 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) 2004 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.setSource(n);
53  preflow_test.setFlow(flow);
54
55  preflow_test.phase1(PType::NO_FLOW);
56  preflow_test.minCut(cut);
57
58  preflow_test.phase2();
59  preflow_test.setTarget(n);
60  preflow_test.setCap(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.tail(e)] && !cut[g.head(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")) + "/preflow_graph.dim";
91  }
92  else {
93    f_name = "preflow_graph.dim";
94  }
95 
96  std::ifstream file(f_name.c_str());
97 
98  check(file, "Input file '" << f_name << "' not found.");
99 
100  Graph g;
101  Node s, t;
102  CapMap cap(g);
103  readDimacs(file, g, cap, s, t);
104
105  FlowMap flow(g,0);
106
107 
108
109  PType preflow_test(g, s, t, cap, flow);
110  preflow_test.run(PType::ZERO_FLOW);
111   
112  CutMap min_cut(g,false);
113  preflow_test.minCut(min_cut);
114  int min_cut_value=cut_value(g,min_cut,cap);
115   
116  CutMap min_min_cut(g,false);
117  preflow_test.minMinCut(min_min_cut);
118  int min_min_cut_value=cut_value(g,min_min_cut,cap);
119   
120  CutMap max_min_cut(g,false);
121  preflow_test.maxMinCut(max_min_cut);
122  int max_min_cut_value=cut_value(g,max_min_cut,cap);
123
124  check(preflow_test.flowValue() == min_cut_value &&
125        min_cut_value == min_min_cut_value &&
126        min_min_cut_value == max_min_cut_value,
127        "The max flow value is not equal to the three min cut values.");
128
129  int flow_value=preflow_test.flowValue();
130
131
132
133  for(EdgeIt e(g); e!=INVALID; ++e) cap[e]=2*cap[e];
134  preflow_test.setCap(cap); 
135
136  preflow_test.phase1(PType::PRE_FLOW);
137
138  CutMap min_cut1(g,false);
139  preflow_test.minCut(min_cut1);
140  min_cut_value=cut_value(g,min_cut1,cap);
141   
142  check(preflow_test.flowValue() == min_cut_value &&
143        min_cut_value == 2*flow_value,
144        "The max flow value or the min cut value is wrong.");
145
146  preflow_test.phase2();
147
148  CutMap min_cut2(g,false);
149  preflow_test.minCut(min_cut2);
150  min_cut_value=cut_value(g,min_cut2,cap);
151   
152  CutMap min_min_cut2(g,false);
153  preflow_test.minMinCut(min_min_cut2);
154  min_min_cut_value=cut_value(g,min_min_cut2,cap);
155 
156  preflow_test.maxMinCut(max_min_cut);
157  max_min_cut_value=cut_value(g,max_min_cut,cap);
158
159  check(preflow_test.flowValue() == min_cut_value &&
160        min_cut_value == min_min_cut_value &&
161        min_min_cut_value == max_min_cut_value &&
162        min_cut_value == 2*flow_value,
163        "The max flow value or the three min cut values were not doubled");
164
165
166
167  EdgeIt e(g);
168  for( int i=1; i==10; ++i ) {
169    flow.set(e,0);
170    ++e;
171  }
172
173  preflow_test.setFlow(flow);
174
175  NodeIt tmp1(g,s);
176  ++tmp1;
177  if ( tmp1 != INVALID ) s=tmp1;
178
179  NodeIt tmp2(g,t);
180  ++tmp2;
181  if ( tmp2 != INVALID ) t=tmp2;
182
183  preflow_test.setSource(s);
184  preflow_test.setTarget(t);
185 
186  preflow_test.run();
187
188  CutMap min_cut3(g,false);
189  preflow_test.minCut(min_cut3);
190  min_cut_value=cut_value(g,min_cut3,cap);
191   
192  CutMap min_min_cut3(g,false);
193  preflow_test.minMinCut(min_min_cut3);
194  min_min_cut_value=cut_value(g,min_min_cut3,cap);
195   
196  preflow_test.maxMinCut(max_min_cut);
197  max_min_cut_value=cut_value(g,max_min_cut,cap);
198
199  check(preflow_test.flowValue() == min_cut_value &&
200        min_cut_value == min_min_cut_value &&
201        min_min_cut_value == max_min_cut_value,
202        "The max flow value or the three min cut values are incorrect.");
203}
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