Rewrite of the tutorial.
1. Quicker starting point.
2. Better discussion of derivatives.
3. Better hyperlinking to code and class documentation.
4. New robust estimation example.
5. Better naming of example code.
6. Removed dependency on gflags in all the core examples covered
in the tutorial.
Change-Id: Ibf3c7fe946fa2b4d22f8916a9366df267d34ca26
diff --git a/examples/helloworld_numeric_diff.cc b/examples/helloworld_numeric_diff.cc
new file mode 100644
index 0000000..026b155
--- /dev/null
+++ b/examples/helloworld_numeric_diff.cc
@@ -0,0 +1,79 @@
+// 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:
+//
+// * 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: keir@google.com (Keir Mierle)
+//
+// Minimize 0.5 (10 - x)^2 using jacobian matrix computed using
+// numeric differentiation.
+
+#include "ceres/ceres.h"
+#include "glog/logging.h"
+
+using ceres::NumericDiffCostFunction;
+using ceres::CENTRAL;
+using ceres::CostFunction;
+using ceres::Problem;
+using ceres::Solver;
+using ceres::Solve;
+
+// A cost functor that implements the residual r = 10 - x.
+struct CostFunctor {
+ bool operator()(const double* const x, double* residual) const {
+ residual[0] = 10.0 - x[0];
+ return true;
+ }
+};
+
+int main(int argc, char** argv) {
+ google::InitGoogleLogging(argv[0]);
+
+ // The variable to solve for with its initial value. It will be
+ // mutated in place by the solver.
+ double x = 0.5;
+ const double initial_x = x;
+
+ // Build the problem.
+ Problem problem;
+
+ // Set up the only cost function (also known as residual). This uses
+ // numeric differentiation to obtain the derivative (jacobian).
+ CostFunction* cost_function =
+ new NumericDiffCostFunction<CostFunctor, CENTRAL, 1, 1> (new CostFunctor);
+ problem.AddResidualBlock(cost_function, NULL, &x);
+
+ // Run the solver!
+ Solver::Options options;
+ options.minimizer_progress_to_stdout = true;
+ Solver::Summary summary;
+ Solve(options, &problem, &summary);
+
+ std::cout << summary.BriefReport() << "\n";
+ std::cout << "x : " << initial_x
+ << " -> " << x << "\n";
+ return 0;
+}
