examples/slam/pose_graph_2d/angle_manifold.h

// Ceres Solver - A fast non-linear least squares minimizer
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// Author: vitus@google.com (Michael Vitus)
//         sameeragarwal@google.com (Sameer Agarwal)

#ifndef CERES_EXAMPLES_POSE_GRAPH_2D_ANGLE_MANIFOLD_H_
#define CERES_EXAMPLES_POSE_GRAPH_2D_ANGLE_MANIFOLD_H_

#include "ceres/autodiff_manifold.h"
#include "normalize_angle.h"

namespace ceres::examples {

// Defines a manifold for updating the angle to be constrained in [-pi to pi).
class AngleManifold {
 public:
  template <typename T>
  bool Plus(const T* x_radians,
            const T* delta_radians,
            T* x_plus_delta_radians) const {
    *x_plus_delta_radians = NormalizeAngle(*x_radians + *delta_radians);
    return true;
  }

  template <typename T>
  bool Minus(const T* y_radians,
             const T* x_radians,
             T* y_minus_x_radians) const {
    *y_minus_x_radians =
        NormalizeAngle(*y_radians) - NormalizeAngle(*x_radians);

    return true;
  }

  static ceres::Manifold* Create() {
    return new ceres::AutoDiffManifold<AngleManifold, 1, 1>;
  }
};

}  // namespace ceres::examples

#endif  // CERES_EXAMPLES_POSE_GRAPH_2D_ANGLE_MANIFOLD_H_