scipy.spatial.transform.Rotation.

as_matrix#

Rotation.as_matrix()[source]#

Represent as rotation matrix.

3D rotations can be represented using rotation matrices, which are 3 x 3 real orthogonal matrices with determinant equal to +1 [1].

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

Shape depends on shape of inputs used for initialization.

Notes

This function was called as_dcm before.

Added in version 1.4.0.

Array API Standard Support

as_matrix 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_rotvec([0, 0, np.pi/2])
>>> r.as_matrix()
array([[ 2.22044605e-16, -1.00000000e+00,  0.00000000e+00],
       [ 1.00000000e+00,  2.22044605e-16,  0.00000000e+00],
       [ 0.00000000e+00,  0.00000000e+00,  1.00000000e+00]])
>>> r.as_matrix().shape
(3, 3)

Represent a stack with a single rotation:

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

Represent multiple rotations:

>>> r = R.from_rotvec([[np.pi/2, 0, 0], [0, 0, np.pi/2]])
>>> r.as_matrix()
array([[[ 1.00000000e+00,  0.00000000e+00,  0.00000000e+00],
        [ 0.00000000e+00,  2.22044605e-16, -1.00000000e+00],
        [ 0.00000000e+00,  1.00000000e+00,  2.22044605e-16]],
       [[ 2.22044605e-16, -1.00000000e+00,  0.00000000e+00],
        [ 1.00000000e+00,  2.22044605e-16,  0.00000000e+00],
        [ 0.00000000e+00,  0.00000000e+00,  1.00000000e+00]]])
>>> r.as_matrix().shape
(2, 3, 3)
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