scipy.spatial.transform.Rotation.

as_rotvec#

Rotation.as_rotvec(degrees=False)[source]#

Represent as rotation vectors.

A rotation vector is a 3 dimensional vector which is co-directional to the axis of rotation and whose norm gives the angle of rotation [1].

Parameters:
degreesboolean, optional

Returned magnitudes are in degrees if this flag is True, else they are in radians. Default is False.

Added in version 1.7.0.

Returns:
rotvecndarray, shape (3,) or (N, 3)

Shape depends on shape of inputs used for initialization.

Notes

Array API Standard Support

as_rotvec has experimental support for Python Array API Standard compatible backends in addition to NumPy. Please consider testing these features by setting an environment variable SCIPY_ARRAY_API=1 and providing CuPy, PyTorch, JAX, or Dask arrays as array arguments. The following combinations of backend and device (or other capability) are supported.

Library

CPU

GPU

NumPy

✅

n/a

CuPy

n/a

✅

PyTorch

✅

✅

JAX

✅

✅

Dask

⛔

n/a

See Support for the array API standard for more information.

References

Examples

>>> from scipy.spatial.transform import Rotation as R
>>> import numpy as np

Represent a single rotation:

>>> r = R.from_euler('z', 90, degrees=True)
>>> r.as_rotvec()
array([0.        , 0.        , 1.57079633])
>>> r.as_rotvec().shape
(3,)

Represent a rotation in degrees:

>>> r = R.from_euler('YX', (-90, -90), degrees=True)
>>> s = r.as_rotvec(degrees=True)
>>> s
array([-69.2820323, -69.2820323, -69.2820323])
>>> np.linalg.norm(s)
120.00000000000001

Represent a stack with a single rotation:

>>> r = R.from_quat([[0, 0, 1, 1]])
>>> r.as_rotvec()
array([[0.        , 0.        , 1.57079633]])
>>> r.as_rotvec().shape
(1, 3)

Represent multiple rotations in a single object:

>>> r = R.from_quat([[0, 0, 1, 1], [1, 1, 0, 1]])
>>> r.as_rotvec()
array([[0.        , 0.        , 1.57079633],
       [1.35102172, 1.35102172, 0.        ]])
>>> r.as_rotvec().shape
(2, 3)
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