Test RotationDeltaCostFunctor (#721)

cartographer/mapping_3d/scan_matching/rotation_delta_cost_functor.h

@@ -20,6 +20,7 @@
 #include <cmath>
 
 #include "Eigen/Core"
+#include "ceres/ceres.h"
 #include "ceres/rotation.h"
 
 namespace cartographer {

cartographer/mapping_3d/scan_matching/rotation_delta_cost_functor_test.cc

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2017 The Cartographer Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "cartographer/mapping_3d/scan_matching/rotation_delta_cost_functor.h"
+
+#include "gtest/gtest.h"
+
+namespace cartographer {
+namespace mapping_3d {
+namespace scan_matching {
+namespace {
+
+constexpr double kPrecision = 1e-8;
+
+double ComputeRotationDeltaSquaredCost(
+    const Eigen::Quaterniond& rotation, const double scaling_factor,
+    const Eigen::Quaterniond& target_rotation) {
+  std::unique_ptr<ceres::CostFunction> cost_function(
+      RotationDeltaCostFunctor::CreateAutoDiffCostFunction(scaling_factor,
+                                                           target_rotation));
+  const std::array<double, 4> parameter_quaternion = {
+      {rotation.w(), rotation.x(), rotation.y(), rotation.z()}};
+  const std::vector<const double*> parameters = {parameter_quaternion.data()};
+  std::vector<double> residuals(cost_function->num_residuals());
+  EXPECT_TRUE(cost_function->Evaluate(parameters.data(), residuals.data(),
+                                      nullptr /* jacobian */));
+  double sum_of_squares = 0;
+  for (double residual : residuals) {
+    sum_of_squares += residual * residual;
+  }
+  return sum_of_squares;
+}
+
+TEST(RotationDeltaCostFunctorTest, SameRotationGivesZeroCost) {
+  EXPECT_NEAR(
+      0.,
+      ComputeRotationDeltaSquaredCost(Eigen::Quaterniond::Identity(), 1.0,
+                                      Eigen::Quaterniond::Identity()),
+      kPrecision);
+
+  Eigen::Quaterniond rotation(
+      Eigen::AngleAxisd(0.9, Eigen::Vector3d(0.2, 0.1, 0.3).normalized()));
+  EXPECT_NEAR(0., ComputeRotationDeltaSquaredCost(rotation, 1.0, rotation),
+              kPrecision);
+}
+
+TEST(RotationDeltaCostFunctorTest, ComputesCorrectCost) {
+  double scaling_factor = 1.2;
+  double angle = 0.8;
+  Eigen::Quaterniond rotation(
+      Eigen::AngleAxisd(angle, Eigen::Vector3d(0.2, 0.1, 0.8).normalized()));
+  Eigen::Quaterniond target_rotation(
+      Eigen::AngleAxisd(0.2, Eigen::Vector3d(-0.5, 0.3, 0.4).normalized()));
+  double expected_cost = std::pow(scaling_factor * std::sin(angle / 2.0), 2);
+  EXPECT_NEAR(expected_cost,
+              ComputeRotationDeltaSquaredCost(rotation, scaling_factor,
+                                              Eigen::Quaterniond::Identity()),
+              kPrecision);
+  EXPECT_NEAR(expected_cost,
+              ComputeRotationDeltaSquaredCost(target_rotation * rotation,
+                                              scaling_factor, target_rotation),
+              kPrecision);
+  EXPECT_NEAR(expected_cost,
+              ComputeRotationDeltaSquaredCost(rotation * target_rotation,
+                                              scaling_factor, target_rotation),
+              kPrecision);
+}
+
+}  // namespace
+}  // namespace scan_matching
+}  // namespace mapping_3d
+}  // namespace cartographer