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scipy.spatial.transform.Rotation.

# from_mrp

static Rotation.from_mrp(mrp)

  Initialize from Modified Rodrigues Parameters (MRPs).

  MRPs are a 3 dimensional vector co-directional to the axis of rotation and whose magnitude is equal to `tan(theta / 4)`, where `theta` is the angle of rotation (in radians) [1].

  MRPs have a singularity at 360 degrees which can be avoided by ensuring the angle of rotation does not exceed 180 degrees, i.e. switching the direction of the rotation when it is past 180 degrees.

  Parameters:
    mrp array_like, shape (…, 3)

      A single vector or an ND array of vectors, where the last dimension contains the rotation parameters.

  Returns:
    rotation `Rotation` instance

      Object containing the rotations represented by input MRPs.

  Notes

  Added in version 1.6.0.

  Array API Standard Support

  `from_mrp` 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

  [1]

  Shuster, M. D. “A Survey of Attitude Representations”, The Journal of Astronautical Sciences, Vol. 41, No.4, 1993, pp. 475-476

  Examples

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

  Initialize a single rotation:

      >>> r = R.from_mrp([0, 0, 1])
      >>> r.as_euler('xyz', degrees=True)
      array([0.        , 0.        , 180.      ])
      >>> r.as_euler('xyz').shape
      (3,)

  Initialize multiple rotations in one object:

      >>> r = R.from_mrp([
      ... [0, 0, 1],
      ... [1, 0, 0]])
      >>> r.as_euler('xyz', degrees=True)
      array([[0.        , 0.        , 180.      ],
             [180.0     , 0.        , 0.        ]])
      >>> r.as_euler('xyz').shape
      (2, 3)

  It is also possible to have a stack of a single rotation:

      >>> r = R.from_mrp([[0, 0, np.pi/2]])
      >>> r.as_euler('xyz').shape
      (1, 3)