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/gradient_problem_solver_test.cc b/internal/ceres/gradient_problem_solver_test.cc
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+// 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: strandmark@google.com (Petter Strandmark)
+
+#include "ceres/gradient_problem.h"
+#include "ceres/gradient_problem_solver.h"
+
+#include "gtest/gtest.h"
+
+namespace ceres {
+namespace internal {
+
+// Rosenbrock function; see http://en.wikipedia.org/wiki/Rosenbrock_function .
+class Rosenbrock : public ceres::FirstOrderFunction {
+ public:
+  virtual ~Rosenbrock() {}
+
+  virtual bool Evaluate(const double* parameters,
+                        double* cost,
+                        double* gradient) const {
+    const double x = parameters[0];
+    const double y = parameters[1];
+
+    cost[0] = (1.0 - x) * (1.0 - x) + 100.0 * (y - x * x) * (y - x * x);
+    if (gradient != NULL) {
+      gradient[0] = -2.0 * (1.0 - x) - 200.0 * (y - x * x) * 2.0 * x;
+      gradient[1] = 200.0 * (y - x * x);
+    }
+    return true;
+  }
+
+  virtual int NumParameters() const { return 2; }
+};
+
+TEST(GradientProblemSolver, SolvesRosenbrockWithDefaultOptions) {
+  const double expected_tolerance = 1e-9;
+  double parameters[2] = {-1.2, 0.0};
+
+  ceres::GradientProblemSolver::Options options;
+  ceres::GradientProblemSolver::Summary summary;
+  ceres::GradientProblem problem(new Rosenbrock());
+  ceres::Solve(options, problem, parameters, &summary);
+
+  EXPECT_EQ(CONVERGENCE, summary.termination_type);
+  EXPECT_NEAR(1.0, parameters[0], expected_tolerance);
+  EXPECT_NEAR(1.0, parameters[1], expected_tolerance);
+}
+
+class QuadraticFunction : public ceres::FirstOrderFunction {
+  virtual ~QuadraticFunction() {}
+  virtual bool Evaluate(const double* parameters,
+                        double* cost,
+                        double* gradient) const {
+    const double x = parameters[0];
+    *cost = 0.5 * (5.0 - x) * (5.0 - x);
+    if (gradient != NULL) {
+      gradient[0] = x - 5.0;
+    }
+
+    return true;
+  }
+  virtual int NumParameters() const { return 1; }
+};
+
+struct RememberingCallback : public IterationCallback {
+  explicit RememberingCallback(double *x) : calls(0), x(x) {}
+  virtual ~RememberingCallback() {}
+  virtual CallbackReturnType operator()(const IterationSummary& summary) {
+    x_values.push_back(*x);
+    return SOLVER_CONTINUE;
+  }
+  int calls;
+  double *x;
+  std::vector<double> x_values;
+};
+
+
+TEST(Solver, UpdateStateEveryIterationOption) {
+  double x = 50.0;
+  const double original_x = x;
+
+  ceres::GradientProblem problem(new QuadraticFunction);
+  ceres::GradientProblemSolver::Options options;
+  RememberingCallback callback(&x);
+  options.callbacks.push_back(&callback);
+  ceres::GradientProblemSolver::Summary summary;
+
+  int num_iterations;
+
+  // First try: no updating.
+  ceres::Solve(options, problem, &x, &summary);
+  num_iterations = summary.iterations.size() - 1;
+  EXPECT_GT(num_iterations, 1);
+  for (int i = 0; i < callback.x_values.size(); ++i) {
+    EXPECT_EQ(50.0, callback.x_values[i]);
+  }
+
+  // Second try: with updating
+  x = 50.0;
+  options.update_state_every_iteration = true;
+  callback.x_values.clear();
+  ceres::Solve(options, problem, &x, &summary);
+  num_iterations = summary.iterations.size() - 1;
+  EXPECT_GT(num_iterations, 1);
+  EXPECT_EQ(original_x, callback.x_values[0]);
+  EXPECT_NE(original_x, callback.x_values[1]);
+}
+
+}  // namespace internal
+}  // namespace ceres