`scipy.spatial.transform._rotation:Rotation.from_mrp`

source: build-install/usr/lib/python3.14/site-packages/scipy/spatial/transform/_rotation.py:932

Signature

staticmethoddef from_mrp(mrp: ArrayLike) → Rotation

Summary

Initialize from Modified Rodrigues Parameters (MRPs).

Extended Summary

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

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.]])

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)

Aliases

scipy.spatial.transform.Rotation.from_mrp