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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: sameeragarwal@google.com (Sameer Agarwal)
+//
+// A simple example of optimizing a sampled function by using cubic
+// interpolation.
+
+#include "ceres/ceres.h"
+#include "ceres/cubic_interpolation.h"
+#include "glog/logging.h"
+
+using ceres::Grid1D;
+using ceres::CubicInterpolator;
+using ceres::AutoDiffCostFunction;
+using ceres::CostFunction;
+using ceres::Problem;
+using ceres::Solver;
+using ceres::Solve;
+
+// A simple cost functor that interfaces an interpolated table of
+// values with automatic differentiation.
+struct InterpolatedCostFunctor {
+ explicit InterpolatedCostFunctor(
+ const CubicInterpolator<Grid1D<double> >& interpolator)
+ : interpolator_(interpolator) {
+ }
+
+ template<typename T> bool operator()(const T* x, T* residuals) const {
+ interpolator_.Evaluate(*x, residuals);
+ return true;
+ }
+
+ static CostFunction* Create(
+ const CubicInterpolator<Grid1D<double> >& interpolator) {
+ return new AutoDiffCostFunction<InterpolatedCostFunctor, 1, 1>(
+ new InterpolatedCostFunctor(interpolator));
+ }
+
+ private:
+ const CubicInterpolator<Grid1D<double> >& interpolator_;
+};
+
+int main(int argc, char** argv) {
+ google::InitGoogleLogging(argv[0]);
+
+ // Evaluate the function f(x) = (x - 4.5)^2;
+ const int kNumSamples = 10;
+ double values[kNumSamples];
+ for (int i = 0; i < kNumSamples; ++i) {
+ values[i] = (i - 4.5) * (i - 4.5);
+ }
+
+ Grid1D<double> array(values, 0, kNumSamples);
+ CubicInterpolator<Grid1D<double> > interpolator(array);
+
+ double x = 1.0;
+ Problem problem;
+ CostFunction* cost_function = InterpolatedCostFunctor::Create(interpolator);
+ problem.AddResidualBlock(cost_function, NULL, &x);
+
+ Solver::Options options;
+ options.minimizer_progress_to_stdout = true;
+ Solver::Summary summary;
+ Solve(options, &problem, &summary);
+ std::cout << summary.BriefReport() << "\n";
+ std::cout << "Expected x: 4.5. Actual x : " << x << std::endl;
+ return 0;
+}