qiskit.quantum_info.Quaternion

class Quaternion(data)

A class representing a Quaternion.

__init__(data)

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__(data)	Initialize self.
from_axis_rotation(angle, axis)	Return quaternion for rotation about given axis.
from_euler(angles[, order])	Generate a quaternion from a set of Euler angles.
norm()	Norm of quaternion.
normalize([inplace])	Normalizes a Quaternion to unit length so that it represents a valid rotation.
to_matrix()	Converts a unit-length quaternion to a rotation matrix.
to_zyz()	Converts a unit-length quaternion to a sequence of ZYZ Euler angles.

classmethod from_axis_rotation(angle, axis)

Return quaternion for rotation about given axis.

Parameters

• angle (float) – Angle in radians.

• axis (str) – Axis for rotation

Returns

Quaternion for axis rotation.

Return type

Quaternion

Raises

ValueError – Invalid input axis.

classmethod from_euler(angles, order='yzy')

Generate a quaternion from a set of Euler angles.

Parameters

• angles (array_like) – Array of Euler angles.

• order (str) – Order of Euler rotations. ‘yzy’ is default.

Returns

Quaternion representation of Euler rotation.

Return type

Quaternion

norm()

Norm of quaternion.

normalize(inplace=False)

Normalizes a Quaternion to unit length so that it represents a valid rotation.

Parameters

inplace (bool) – Do an inplace normalization.

Returns

Normalized quaternion.

Return type

Quaternion

to_matrix()

Converts a unit-length quaternion to a rotation matrix.

Returns

Rotation matrix.

Return type

ndarray

to_zyz()

Converts a unit-length quaternion to a sequence of ZYZ Euler angles.

Returns

Array of Euler angles.

Return type

ndarray