1// Ceres Solver - A fast non-linear least squares minimizer
2// Copyright 2013 Google Inc. All rights reserved.
3// http://code.google.com/p/ceres-solver/
4//
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6// modification, are permitted provided that the following conditions are met:
7//
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9//   this list of conditions and the following disclaimer.
10// * Redistributions in binary form must reproduce the above copyright notice,
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12//   and/or other materials provided with the distribution.
13// * Neither the name of Google Inc. nor the names of its contributors may be
14//   used to endorse or promote products derived from this software without
15//   specific prior written permission.
16//
17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
18// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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28//
29// Author: Sameer Agarwal (sameeragarwal@google.com)
30
31// This include must come before any #ifndef check on Ceres compile options.
32#include "ceres/internal/port.h"
33
34#ifndef CERES_NO_SUITESPARSE
35
36#include "ceres/single_linkage_clustering.h"
37
38#include "ceres/collections_port.h"
39#include "ceres/graph.h"
40#include "gtest/gtest.h"
41
42namespace ceres {
43namespace internal {
44
45TEST(SingleLinkageClustering, GraphHasTwoComponents) {
46  Graph<int> graph;
47  const int kNumVertices = 6;
48  for (int i = 0; i < kNumVertices; ++i) {
49    graph.AddVertex(i);
50  }
51  // Graph structure:
52  //
53  //  0-1-2-3 4-5
54  graph.AddEdge(0, 1, 1.0);
55  graph.AddEdge(1, 2, 1.0);
56  graph.AddEdge(2, 3, 1.0);
57  graph.AddEdge(4, 5, 1.0);
58
59  SingleLinkageClusteringOptions options;
60  HashMap<int, int> membership;
61  ComputeSingleLinkageClustering(options, graph, &membership);
62  EXPECT_EQ(membership.size(), kNumVertices);
63
64  EXPECT_EQ(membership[1], membership[0]);
65  EXPECT_EQ(membership[2], membership[0]);
66  EXPECT_EQ(membership[3], membership[0]);
67  EXPECT_NE(membership[4], membership[0]);
68  EXPECT_NE(membership[5], membership[0]);
69  EXPECT_EQ(membership[4], membership[5]);
70}
71
72TEST(SingleLinkageClustering, ComponentWithWeakLink) {
73  Graph<int> graph;
74  const int kNumVertices = 6;
75  for (int i = 0; i < kNumVertices; ++i) {
76    graph.AddVertex(i);
77  }
78  // Graph structure:
79  //
80  //  0-1-2-3 4-5
81  graph.AddEdge(0, 1, 1.0);
82  graph.AddEdge(1, 2, 1.0);
83  graph.AddEdge(2, 3, 1.0);
84
85  // This component should break up into two.
86  graph.AddEdge(4, 5, 0.5);
87
88  SingleLinkageClusteringOptions options;
89  HashMap<int, int> membership;
90  ComputeSingleLinkageClustering(options, graph, &membership);
91  EXPECT_EQ(membership.size(), kNumVertices);
92
93  EXPECT_EQ(membership[1], membership[0]);
94  EXPECT_EQ(membership[2], membership[0]);
95  EXPECT_EQ(membership[3], membership[0]);
96  EXPECT_NE(membership[4], membership[0]);
97  EXPECT_NE(membership[5], membership[0]);
98  EXPECT_NE(membership[4], membership[5]);
99}
100
101TEST(SingleLinkageClustering, ComponentWithWeakLinkAndStrongLink) {
102  Graph<int> graph;
103  const int kNumVertices = 6;
104  for (int i = 0; i < kNumVertices; ++i) {
105    graph.AddVertex(i);
106  }
107  // Graph structure:
108  //
109  //  0-1-2-3 4-5
110  graph.AddEdge(0, 1, 1.0);
111  graph.AddEdge(1, 2, 1.0);
112  graph.AddEdge(2, 3, 0.5); // Weak link
113  graph.AddEdge(0, 3, 1.0);
114
115  // This component should break up into two.
116  graph.AddEdge(4, 5, 1.0);
117
118  SingleLinkageClusteringOptions options;
119  HashMap<int, int> membership;
120  ComputeSingleLinkageClustering(options, graph, &membership);
121  EXPECT_EQ(membership.size(), kNumVertices);
122
123  EXPECT_EQ(membership[1], membership[0]);
124  EXPECT_EQ(membership[2], membership[0]);
125  EXPECT_EQ(membership[3], membership[0]);
126  EXPECT_EQ(membership[4], membership[5]);
127}
128
129}  // namespace internal
130}  // namespace ceres
131
132#endif  // CERES_NO_SUITESPARSE
133