COIN-OR::LEMON - Graph Library

source: lemon/test/gomory_hu_test.cc @ 636:630c4898c548

Last change on this file since 636:630c4898c548 was 593:d6b40ebb2617, checked in by Peter Kovacs <kpeter@…>, 11 years ago

Doc improvements in GomoryHu? (#66)
And make init() and start() private + bug fix in the test file.

File size: 2.0 KB
Line 
1#include <iostream>
2
3#include "test_tools.h"
4#include <lemon/smart_graph.h>
5#include <lemon/lgf_reader.h>
6#include <lemon/gomory_hu.h>
7#include <cstdlib>
8
9using namespace std;
10using namespace lemon;
11
12typedef SmartGraph Graph;
13
14char test_lgf[] =
15  "@nodes\n"
16  "label\n"
17  "0\n"
18  "1\n"
19  "2\n"
20  "3\n"
21  "4\n"
22  "@arcs\n"
23  "     label capacity\n"
24  "0 1  0     1\n"
25  "1 2  1     1\n"
26  "2 3  2     1\n"
27  "0 3  4     5\n"
28  "0 3  5     10\n"
29  "0 3  6     7\n"
30  "4 2  7     1\n"
31  "@attributes\n"
32  "source 0\n"
33  "target 3\n";
34 
35GRAPH_TYPEDEFS(Graph);
36typedef Graph::EdgeMap<int> IntEdgeMap;
37typedef Graph::NodeMap<bool> BoolNodeMap;
38
39int cutValue(const Graph& graph, const BoolNodeMap& cut,
40             const IntEdgeMap& capacity) {
41
42  int sum = 0;
43  for (EdgeIt e(graph); e != INVALID; ++e) {
44    Node s = graph.u(e);
45    Node t = graph.v(e);
46
47    if (cut[s] != cut[t]) {
48      sum += capacity[e];
49    }
50  }
51  return sum;
52}
53
54
55int main() {
56  Graph graph;
57  IntEdgeMap capacity(graph);
58
59  std::istringstream input(test_lgf);
60  GraphReader<Graph>(graph, input).
61    edgeMap("capacity", capacity).run();
62
63  GomoryHu<Graph> ght(graph, capacity);
64  ght.run();
65
66  for (NodeIt u(graph); u != INVALID; ++u) {
67    for (NodeIt v(graph); v != u; ++v) {
68      Preflow<Graph, IntEdgeMap> pf(graph, capacity, u, v);
69      pf.runMinCut();
70      BoolNodeMap cm(graph);
71      ght.minCutMap(u, v, cm);
72      check(pf.flowValue() == ght.minCutValue(u, v), "Wrong cut 1");
73      check(cm[u] != cm[v], "Wrong cut 3");
74      check(pf.flowValue() == cutValue(graph, cm, capacity), "Wrong cut 2");
75
76      int sum=0;
77      for(GomoryHu<Graph>::MinCutEdgeIt a(ght, u, v);a!=INVALID;++a)
78        sum+=capacity[a];
79      check(sum == ght.minCutValue(u, v), "Problem with MinCutEdgeIt");
80
81      sum=0;
82      for(GomoryHu<Graph>::MinCutNodeIt n(ght, u, v,true);n!=INVALID;++n)
83        sum++;
84      for(GomoryHu<Graph>::MinCutNodeIt n(ght, u, v,false);n!=INVALID;++n)
85        sum++;
86      check(sum == countNodes(graph), "Problem with MinCutNodeIt");
87     
88    }
89  }
90 
91  return 0;
92}
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