Orientation, rotation, quaternion, and crystal symmetry handling in Python.
Project description
orix is an open-source python library for analysing orientations and crystal symmetry.
The package defines objects and functions for the analysis of orientations represented as quaternions or 3D rotation vectors accounting for crystal symmetry. Functionality buils primarily on top of numpy and matplotlib and heavily inspired by the MATLAB package MTEX.
If analysis using orix forms a part of published work please cite the github repository.
orix (this version) is released under the GPL v3 license.
Getting started
The use of orix should feel familiar to the use of numpy, but rather than cells of numbers, the cells contain single 3d objects, such as vectors or quaternions. They can all be created using tuples, lists, numpy arrays, or other numpy-compatible iterables, and will raise an error if constructed with the incorrect number of dimensions. Basic examples are given below.
Vectors
Vectors are 3d objects representing positions or directions with “magnitude”. They can be added and subtracted with integers, floats, or other vectors (provided the data are of compatible shapes) and have several further unique operations.
>>> import numpy as np
>>> from orix.vector import Vector3d
>>> v = Vector3d((1, 1, -1))
>>> w_array = np.array([[[1, 0, 0], [0, 0, -1]], [[1, 1, 0], [-1, 0, -1]]])
>>> w = Vector3d(w_array)
>>> v + w
# Vector3d (2, 2)
# [[[ 2 1 -1]
# [ 1 1 -2]]
#
# [[ 2 2 -1]
# [ 0 1 -2]]]
>>> v.dot(w)
# array([[1, 1],
# [2, 0]])
>>> v.cross(w)
# Vector3d (2, 2)
# [[[ 0 -1 -1]
# [-1 1 0]]
#
# [[ 1 -1 0]
# [-1 2 1]]]
>>> v.unit
# Vector3d (1,)
# [[ 0.5774 0.5774 -0.5774]]
>>> w[0]
# Vector3d (2,)
# [[ 1 0 0]
# [ 0 0 -1]]
>>> w[:, 0]
# Vector3d (2,)
# [[1 0 0]
# [1 1 0]]Quaternions
Quaternions are four-dimensional data structures. Unit quaternions are often used for representing rotations in 3d. Quaternion multiplication is defined and can be applied to either other quaternions or vectors.
>>> from orix.quaternion.rotation import Rotation
>>> p = Rotation([0.5, 0.5, 0.5, 0.5])
>>> q = Rotation([0, 1, 0, 0])
>>> p.axis
# Vector3d (1,)
# [[0.5774 0.5774 0.5774]]
>>> p.angle
# array([2.0943951])
>>> p * q
# Rotation (1,)
# [[-0.5 0.5 0.5 -0.5]]
>>> p * ~p # (unit rotation)
# Rotation (1,)
# [[1. 0. 0. 0.]]
>>> p.to_euler() # (Euler angles in the Bunge convention)
# array([[1.57079633, 1.57079633, 0. ]])Release history Release notifications | RSS feed
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