| // Ceres Solver - A fast non-linear least squares minimizer |
| // Copyright 2021 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: sameeragarwal@google.com (Sameer Agarwal) |
| |
| #include "ceres/ceres.h" |
| #include "glog/logging.h" |
| |
| // f(x,y) = (1-x)^2 + 100(y - x^2)^2; |
| class Rosenbrock final : public ceres::FirstOrderFunction { |
| public: |
| |
| bool Evaluate(const double* parameters, |
| double* cost, |
| double* gradient) const override { |
| 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) { |
| gradient[0] = -2.0 * (1.0 - x) - 200.0 * (y - x * x) * 2.0 * x; |
| gradient[1] = 200.0 * (y - x * x); |
| } |
| |
| return true; |
| } |
| |
| int NumParameters() const override { return 2; } |
| }; |
| |
| int main(int argc, char** argv) { |
| google::InitGoogleLogging(argv[0]); |
| |
| double parameters[2] = {-1.2, 1.0}; |
| |
| ceres::GradientProblemSolver::Options options; |
| options.minimizer_progress_to_stdout = true; |
| |
| ceres::GradientProblemSolver::Summary summary; |
| ceres::GradientProblem problem(new Rosenbrock()); |
| ceres::Solve(options, problem, parameters, &summary); |
| |
| std::cout << summary.FullReport() << "\n"; |
| std::cout << "Initial x: " << -1.2 << " y: " << 1.0 << "\n"; |
| std::cout << "Final x: " << parameters[0] << " y: " << parameters[1] |
| << "\n"; |
| return 0; |
| } |