| // Ceres Solver - A fast non-linear least squares minimizer |
| // Copyright 2010, 2011, 2012 Google Inc. All rights reserved. |
| // http://code.google.com/p/ceres-solver/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // |
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| // 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" |
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| // |
| // Author: keir@google.com (Keir Mierle) |
| // |
| // A simple example of using the Ceres minimizer. |
| // |
| // Minimize 0.5 (10 - x)^2 using analytic jacobian matrix. |
| |
| #include <vector> |
| #include "ceres/ceres.h" |
| #include "gflags/gflags.h" |
| #include "glog/logging.h" |
| |
| using ceres::SizedCostFunction; |
| using ceres::Problem; |
| using ceres::Solver; |
| using ceres::Solve; |
| |
| class SimpleCostFunction |
| : public SizedCostFunction<1 /* number of residuals */, |
| 1 /* size of first parameter */> { |
| public: |
| virtual ~SimpleCostFunction() {} |
| virtual bool Evaluate(double const* const* parameters, |
| double* residuals, |
| double** jacobians) const { |
| double x = parameters[0][0]; |
| |
| // f(x) = 10 - x. |
| residuals[0] = 10 - x; |
| |
| // f'(x) = -1. Since there's only 1 parameter and that parameter |
| // has 1 dimension, there is only 1 element to fill in the |
| // jacobians. |
| if (jacobians != NULL && jacobians[0] != NULL) { |
| jacobians[0][0] = -1; |
| } |
| return true; |
| } |
| }; |
| |
| int main(int argc, char** argv) { |
| google::ParseCommandLineFlags(&argc, &argv, true); |
| google::InitGoogleLogging(argv[0]); |
| |
| // The variable with its initial value that we will be solving for. |
| double x = 5.0; |
| |
| // Build the problem. |
| Problem problem; |
| // Set up the only cost function (also known as residual). |
| problem.AddResidualBlock(new SimpleCostFunction, NULL, &x); |
| |
| // Run the solver! |
| Solver::Options options; |
| options.max_num_iterations = 10; |
| options.linear_solver_type = ceres::DENSE_QR; |
| options.minimizer_progress_to_stdout = true; |
| Solver::Summary summary; |
| Solve(options, &problem, &summary); |
| std::cout << summary.BriefReport() << "\n"; |
| std::cout << "x : 5.0 -> " << x << "\n"; |
| return 0; |
| } |