Squashed 'third_party/ceres/' content from commit e51e9b4
Change-Id: I763587619d57e594d3fa158dc3a7fe0b89a1743b
git-subtree-dir: third_party/ceres
git-subtree-split: e51e9b46f6ca88ab8b2266d0e362771db6d98067
diff --git a/internal/ceres/single_linkage_clustering_test.cc b/internal/ceres/single_linkage_clustering_test.cc
new file mode 100644
index 0000000..281c281
--- /dev/null
+++ b/internal/ceres/single_linkage_clustering_test.cc
@@ -0,0 +1,125 @@
+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2015 Google Inc. All rights reserved.
+// http://ceres-solver.org/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+// used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: Sameer Agarwal (sameeragarwal@google.com)
+
+#include "ceres/single_linkage_clustering.h"
+
+#include <unordered_map>
+#include "ceres/graph.h"
+#include "gtest/gtest.h"
+
+namespace ceres {
+namespace internal {
+
+TEST(SingleLinkageClustering, GraphHasTwoComponents) {
+ WeightedGraph<int> graph;
+ const int kNumVertices = 6;
+ for (int i = 0; i < kNumVertices; ++i) {
+ graph.AddVertex(i);
+ }
+ // Graph structure:
+ //
+ // 0-1-2-3 4-5
+ graph.AddEdge(0, 1, 1.0);
+ graph.AddEdge(1, 2, 1.0);
+ graph.AddEdge(2, 3, 1.0);
+ graph.AddEdge(4, 5, 1.0);
+
+ SingleLinkageClusteringOptions options;
+ std::unordered_map<int, int> membership;
+ ComputeSingleLinkageClustering(options, graph, &membership);
+ EXPECT_EQ(membership.size(), kNumVertices);
+
+ EXPECT_EQ(membership[1], membership[0]);
+ EXPECT_EQ(membership[2], membership[0]);
+ EXPECT_EQ(membership[3], membership[0]);
+ EXPECT_NE(membership[4], membership[0]);
+ EXPECT_NE(membership[5], membership[0]);
+ EXPECT_EQ(membership[4], membership[5]);
+}
+
+TEST(SingleLinkageClustering, ComponentWithWeakLink) {
+ WeightedGraph<int> graph;
+ const int kNumVertices = 6;
+ for (int i = 0; i < kNumVertices; ++i) {
+ graph.AddVertex(i);
+ }
+ // Graph structure:
+ //
+ // 0-1-2-3 4-5
+ graph.AddEdge(0, 1, 1.0);
+ graph.AddEdge(1, 2, 1.0);
+ graph.AddEdge(2, 3, 1.0);
+
+ // This component should break up into two.
+ graph.AddEdge(4, 5, 0.5);
+
+ SingleLinkageClusteringOptions options;
+ std::unordered_map<int, int> membership;
+ ComputeSingleLinkageClustering(options, graph, &membership);
+ EXPECT_EQ(membership.size(), kNumVertices);
+
+ EXPECT_EQ(membership[1], membership[0]);
+ EXPECT_EQ(membership[2], membership[0]);
+ EXPECT_EQ(membership[3], membership[0]);
+ EXPECT_NE(membership[4], membership[0]);
+ EXPECT_NE(membership[5], membership[0]);
+ EXPECT_NE(membership[4], membership[5]);
+}
+
+TEST(SingleLinkageClustering, ComponentWithWeakLinkAndStrongLink) {
+ WeightedGraph<int> graph;
+ const int kNumVertices = 6;
+ for (int i = 0; i < kNumVertices; ++i) {
+ graph.AddVertex(i);
+ }
+ // Graph structure:
+ //
+ // 0-1-2-3 4-5
+ graph.AddEdge(0, 1, 1.0);
+ graph.AddEdge(1, 2, 1.0);
+ graph.AddEdge(2, 3, 0.5); // Weak link
+ graph.AddEdge(0, 3, 1.0);
+
+ // This component should break up into two.
+ graph.AddEdge(4, 5, 1.0);
+
+ SingleLinkageClusteringOptions options;
+ std::unordered_map<int, int> membership;
+ ComputeSingleLinkageClustering(options, graph, &membership);
+ EXPECT_EQ(membership.size(), kNumVertices);
+
+ EXPECT_EQ(membership[1], membership[0]);
+ EXPECT_EQ(membership[2], membership[0]);
+ EXPECT_EQ(membership[3], membership[0]);
+ EXPECT_EQ(membership[4], membership[5]);
+}
+
+} // namespace internal
+} // namespace ceres