Hei Shing Helson Go's C++ math library

This is a repository of my personal implementations of various mathematical functions as a header-only C++ library.

This library currently contains 4 files, shown below.

├── include
│   └── hs293go
│       ├── frame_conversions.hpp
│       ├── geo.hpp
│       ├── math.hpp
│       └── rotation.hpp

• frame_conversions.hpp: Contains functions for converting between NED/ENU coordinate frames.
  • Replacement/reimplementation of Mavros's frame_tf.h
• geo.hpp: Contains functions for geodetic calculations
  • Independent porting of a few functions from Matlab's Mapping Toolbox
    • lla2ecef: Convert from LLA to ECEF coordinates
    • enu2ecef: Convert from ENU to ECEF coordinates
    • lla2enu: Convert from LLA to ENU coordinates
• math.hpp: Contains a few bread and butter mathematical functions I found useful in Matlab or numpy
  • IsClose: Check if two floating point numbers are close to each other (from python's math.isclose)
  • wrapToPi: Wrap an angle to the range [-π, π] (Matlab builtin, edge handling semantics differ)
  • wrapTo2Pi: Wrap an angle to the range [0, 2π] (Matlab builtin, edge handling semantics differ)
  • wrapTo180: Wrap an angle to the range [-180°, 180°] (Matlab builtin, edge handling semantics differ)
  • wrapTo360: Wrap an angle to the range [0°, 360°] (Matlab builtin, edge handling semantics differ)
  • rad2deg: Convert radians to degrees (Matlab builtin)
  • deg2rad: Convert degrees to radians (Matlab builtin)
• rotation.hpp: Contains functions for converting between rotation representations
  • Many of these functions are Eigen reimplementations of Ceres's rotation.h
  • hat: Convert a 3D vector to a skew-symmetric matrix
  • vee: Convert a skew-symmetric matrix to a 3D vector
  • QuaternionToAngleAxis: Convert a quaternion to an angle-axis representation
  • AngleAxisToQuaternion: Convert an angle-axis representation to a quaternion
  • AngleAxisToRotationMatrix: Convert an angle-axis representation to a rotation matrix
  • RotationMatrixToAngleAxis: Convert a rotation matrix to an angle-axis representation
  • EulerAnglesToQuaternion: Convert aerospace passive world-to-body-ZYX euler angles to a passive body-to-world quaternion
  • QuaternionToEulerAngles: Convert a passive body-to-world quaternion to aerospace passive world-to-body-ZYX euler angles
  • Negated: Negate a quaternion by flipping the sign of all components. The result represents the same rotation as the input quaternion.
  • MatchSign: Match the sign/hemisphere of a quaternion (first) to a reference quaternion (second). Useful in trajectory optimization problems to ensure continuous quaternion representations.
  • CanonicalizePositiveW: Canonicalize a quaternion to have a positive scalar component. The result represents the same rotation as the input quaternion.