siconos.mechanics.quaternions module

Utilities to handle quaternions in the siconos.mechanics package

usage example:

>>> import siconos.mechanics.quaternions as quat
>>> phi, theta, psi = quat.euler_from_quaternion(q0, q1, q2, q3)
siconos.mechanics.quaternions.euler_from_quaternion(q0, q1, q2, q3)[source]

Convert a quaternion into Euler angles (phi, theta, psi).

Parameters:

  • q0 (float or ndarray) – Composante scalaire du quaternion.

  • q1 (float or ndarray) – Première composante vectorielle.

  • q2 (float or ndarray) – Deuxième composante vectorielle.

  • q3 (float or ndarray) – Troisième composante vectorielle.

Returns:

tuple of ndarray – (phi, theta, psi), angles d’Euler en radians.

Example

>>> euler_from_quaternion(1, 0, 0, 0)
(0.0, 0.0, 0.0)
siconos.mechanics.quaternions.quaternion_get(orientation)[source]

Converts the orientation (either axis-angle or quaternion) into a quaternion representation.

If the input is already a quaternion, it is returned as-is.

Parameters:

orientation (np array or tuple) – The orientation in either of the following formats: - Axis-angle: ([x, y, z], angle) where [x, y, z] is a 3D vector and angle is a float. - Quaternion: [w, x, y, z] where w, x, y, z are the quaternion components.

siconos.mechanics.quaternions.quaternion_multiply(q1, q0)[source]