| // Ceres Solver - A fast non-linear least squares minimizer | 
 | // Copyright 2018 Google Inc. All rights reserved. | 
 | // http://ceres-solver.org/ | 
 | // | 
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 | // modification, are permitted provided that the following conditions are met: | 
 | // | 
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 | //   this list of conditions and the following disclaimer. | 
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 | //   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 | 
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 | // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | 
 | // POSSIBILITY OF SUCH DAMAGE. | 
 | // | 
 | // Authors: sameeragarwal@google.com (Sameer Agarwal) | 
 |  | 
 | #include <memory> | 
 |  | 
 | #include "benchmark/benchmark.h" | 
 | #include "ceres/ceres.h" | 
 | #include "ceres/jet.h" | 
 |  | 
 | namespace ceres { | 
 |  | 
 | // From the NIST problem collection. | 
 | struct Rat43CostFunctor { | 
 |   Rat43CostFunctor(const double x, const double y) : x_(x), y_(y) {} | 
 |  | 
 |   template <typename T> | 
 |   bool operator()(const T* parameters, T* residuals) const { | 
 |     const T& b1 = parameters[0]; | 
 |     const T& b2 = parameters[1]; | 
 |     const T& b3 = parameters[2]; | 
 |     const T& b4 = parameters[3]; | 
 |     residuals[0] = b1 * pow(1.0 + exp(b2 - b3 * x_), -1.0 / b4) - y_; | 
 |     return true; | 
 |   } | 
 |  | 
 |  private: | 
 |   const double x_; | 
 |   const double y_; | 
 | }; | 
 |  | 
 | // Simple implementation of autodiff using Jets directly instead of | 
 | // going through the machineary of AutoDiffCostFunction, which does | 
 | // the same thing, but much more generically. | 
 | class Rat43Automatic : public ceres::SizedCostFunction<1, 4> { | 
 |  public: | 
 |   Rat43Automatic(const Rat43CostFunctor* functor) : functor_(functor) {} | 
 |   virtual ~Rat43Automatic() {} | 
 |   virtual bool Evaluate(double const* const* parameters, | 
 |                         double* residuals, | 
 |                         double** jacobians) const { | 
 |     if (!jacobians) { | 
 |       return (*functor_)(parameters[0], residuals); | 
 |     } | 
 |  | 
 |     typedef ceres::Jet<double, 4> JetT; | 
 |     JetT jets[4]; | 
 |     for (int i = 0; i < 4; ++i) { | 
 |       jets[i].a = parameters[0][i]; | 
 |       jets[i].v.setZero(); | 
 |       jets[i].v[i] = 1.0; | 
 |     } | 
 |  | 
 |     JetT result; | 
 |     (*functor_)(jets, &result); | 
 |  | 
 |     residuals[0] = result.a; | 
 |     for (int i = 0; i < 4; ++i) { | 
 |       jacobians[0][i] = result.v[i]; | 
 |     } | 
 |     return true; | 
 |   } | 
 |  | 
 |  private: | 
 |   std::unique_ptr<const Rat43CostFunctor> functor_; | 
 | }; | 
 |  | 
 | static void BM_Rat43AutoDiff(benchmark::State& state) { | 
 |   double parameter_block1[] = {1., 2., 3., 4.}; | 
 |   double* parameters[] = {parameter_block1}; | 
 |  | 
 |   double jacobian1[] = {0.0, 0.0, 0.0, 0.0}; | 
 |   double residuals; | 
 |   double* jacobians[] = {jacobian1}; | 
 |   const double x = 0.2; | 
 |   const double y = 0.3; | 
 |   std::unique_ptr<ceres::CostFunction> cost_function( | 
 |       new ceres::AutoDiffCostFunction<Rat43CostFunctor, 1, 4>( | 
 |           new Rat43CostFunctor(x, y))); | 
 |  | 
 |   while (state.KeepRunning()) { | 
 |     cost_function->Evaluate( | 
 |         parameters, &residuals, state.range(0) ? jacobians : nullptr); | 
 |   } | 
 | } | 
 | BENCHMARK(BM_Rat43AutoDiff)->Arg(0)->Arg(1); | 
 |  | 
 | }  // namespace ceres | 
 |  | 
 | BENCHMARK_MAIN(); |