mirror of
https://github.com/ceres-solver/ceres-solver.git
synced 2026-08-29 08:34:37 +08:00
Sameer Agarwal
3712650941
Remove "using ceres:foo" directives from example code. The using directives actually make the code harder to read unless you already know the ceres API. By making the namespace explicit it is clear to the reader that these are functions and objects from the Ceres API. Change-Id: I89b1281c754bf71c0f82e39e1607c5e40a148388
100 lines
3.7 KiB
C++
100 lines
3.7 KiB
C++
// Ceres Solver - A fast non-linear least squares minimizer
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// Copyright 2023 Google Inc. All rights reserved.
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// http://ceres-solver.org/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are met:
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//
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// * Redistributions of source code must retain the above copyright notice,
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// this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above copyright notice,
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// this list of conditions and the following disclaimer in the documentation
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// and/or other materials provided with the distribution.
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// * Neither the name of Google Inc. nor the names of its contributors may be
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// used to endorse or promote products derived from this software without
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// specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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// POSSIBILITY OF SUCH DAMAGE.
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//
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// Author: keir@google.com (Keir Mierle)
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//
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// A simple example of using the Ceres minimizer.
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//
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// Minimize 0.5 (10 - x)^2 using analytic jacobian matrix.
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#include <vector>
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#include "ceres/ceres.h"
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#include "glog/logging.h"
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// A CostFunction implementing analytically derivatives for the
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// function f(x) = 10 - x.
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class QuadraticCostFunction
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: public ceres::SizedCostFunction<1 /* number of residuals */,
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1 /* size of first parameter */> {
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public:
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bool Evaluate(double const* const* parameters,
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double* residuals,
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double** jacobians) const override {
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double x = parameters[0][0];
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// f(x) = 10 - x.
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residuals[0] = 10 - x;
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// f'(x) = -1. Since there's only 1 parameter and that parameter
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// has 1 dimension, there is only 1 element to fill in the
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// jacobians.
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//
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// Since the Evaluate function can be called with the jacobians
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// pointer equal to nullptr, the Evaluate function must check to see
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// if jacobians need to be computed.
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//
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// For this simple problem it is overkill to check if jacobians[0]
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// is nullptr, but in general when writing more complex
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// CostFunctions, it is possible that Ceres may only demand the
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// derivatives w.r.t. a subset of the parameter blocks.
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if (jacobians != nullptr && jacobians[0] != nullptr) {
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jacobians[0][0] = -1;
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}
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return true;
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}
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};
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int main(int argc, char** argv) {
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google::InitGoogleLogging(argv[0]);
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// The variable to solve for with its initial value. It will be
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// mutated in place by the solver.
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double x = 0.5;
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const double initial_x = x;
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// Build the problem.
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ceres::Problem problem;
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// Set up the only cost function (also known as residual).
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ceres::CostFunction* cost_function = new QuadraticCostFunction;
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problem.AddResidualBlock(cost_function, nullptr, &x);
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// Run the solver!
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ceres::Solver::Options options;
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options.minimizer_progress_to_stdout = true;
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ceres::Solver::Summary summary;
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ceres::Solve(options, &problem, &summary);
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std::cout << summary.BriefReport() << "\n";
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std::cout << "x : " << initial_x << " -> " << x << "\n";
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return 0;
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}
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