1 // Ceres Solver - A fast non-linear least squares minimizer
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3 // http://ceres-solver.org/
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29 // Author: sameeragarwal@google.com (Sameer Agarwal)
31 // A simple example of optimizing a sampled function by using cubic
34 #include "ceres/ceres.h"
35 #include "ceres/cubic_interpolation.h"
36 #include "glog/logging.h"
39 using ceres::CubicInterpolator;
40 using ceres::AutoDiffCostFunction;
41 using ceres::CostFunction;
46 // A simple cost functor that interfaces an interpolated table of
47 // values with automatic differentiation.
48 struct InterpolatedCostFunctor {
49 explicit InterpolatedCostFunctor(
50 const CubicInterpolator<Grid1D<double> >& interpolator)
51 : interpolator_(interpolator) {
54 template<typename T> bool operator()(const T* x, T* residuals) const {
55 interpolator_.Evaluate(*x, residuals);
59 static CostFunction* Create(
60 const CubicInterpolator<Grid1D<double> >& interpolator) {
61 return new AutoDiffCostFunction<InterpolatedCostFunctor, 1, 1>(
62 new InterpolatedCostFunctor(interpolator));
66 const CubicInterpolator<Grid1D<double> >& interpolator_;
69 int main(int argc, char** argv) {
70 google::InitGoogleLogging(argv[0]);
72 // Evaluate the function f(x) = (x - 4.5)^2;
73 const int kNumSamples = 10;
74 double values[kNumSamples];
75 for (int i = 0; i < kNumSamples; ++i) {
76 values[i] = (i - 4.5) * (i - 4.5);
79 Grid1D<double> array(values, 0, kNumSamples);
80 CubicInterpolator<Grid1D<double> > interpolator(array);
84 CostFunction* cost_function = InterpolatedCostFunctor::Create(interpolator);
85 problem.AddResidualBlock(cost_function, NULL, &x);
87 Solver::Options options;
88 options.minimizer_progress_to_stdout = true;
89 Solver::Summary summary;
90 Solve(options, &problem, &summary);
91 std::cout << summary.BriefReport() << "\n";
92 std::cout << "Expected x: 4.5. Actual x : " << x << std::endl;