ceres-solver/internal/ceres/tiny_solver_test_util.h

// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2017 Google Inc. All rights reserved.
// http://ceres-solver.org/
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// Author: mierle@gmail.com (Keir Mierle)

#ifndef CERES_INTERNAL_TINY_SOLVER_TEST_UTIL_H_
#define CERES_INTERNAL_TINY_SOLVER_TEST_UTIL_H_

namespace ceres {

template<typename T>
bool EvaluateResidualsAndJacobians(const T* parameters,
                                   T* residuals,
                                   T* jacobian) {
  T x = parameters[0];
  T y = parameters[1];
  T z = parameters[2];

  residuals[0] = x + static_cast<T>(2) * y + static_cast<T>(4) * z;
  residuals[1] = y * z;

  if (jacobian) {
    jacobian[0 * 2 + 0] = static_cast<T>(1);
    jacobian[0 * 2 + 1] = static_cast<T>(0);

    jacobian[1 * 2 + 0] = static_cast<T>(2);
    jacobian[1 * 2 + 1] = z;

    jacobian[2 * 2 + 0] = static_cast<T>(4);
    jacobian[2 * 2 + 1] = y;
  }
  return true;
}

}  // namespace ceres

#endif  // CERES_INTERNAL_TINY_SOLVER_TEST_UTIL_H_