Quaternion

Quaternion(s, x, y, z)

A class supporting quaternion arithmetic

Initializes the pymolecule.Quaternion class.

PARAMETER	DESCRIPTION
s	????
x	????
y	????
z	????

v = np.zeros(4) instance-attribute

__str__()

String containing quaternion information in the form of s x y z

RETURNS	DESCRIPTION
	A string, containing all information about this quaternion

add(q2)

Adds two quaternions.

PARAMETER	DESCRIPTION
q2	A quaternion, to be added to self.

RETURNS	DESCRIPTION
	A Quaternion, with the values corresponding to self + q2.

copy_of()

Returns a copy of self

invert()

Takes the inverse of the quaternion for "division"

Returns: A Quaternion, with the values corresponding to self^-1

load_from_mat(m)

Converts a rotation matrix that is pure orthogonal (det(matrix)=1) into a Quaternion. Adapted from http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/index.htm

PARAMETER	DESCRIPTION
m	A 2D np.array representing a pure orthogonal matrix.

minus(q2)

Multiplies two quaternions

PARAMETER	DESCRIPTION
q2	A quaternion, to be subtracted from self

RETURNS	DESCRIPTION
	A Quaternion, with the values corresponding to self - q2

multiply(q2)

Multiplies two quaternions

PARAMETER	DESCRIPTION
q2	A quaternion, to be multiplied with self

RETURNS	DESCRIPTION
	A Quaternion, with the values corresponding to self * q2

normalize()

Normalizes the quaternion.

RETURNS	DESCRIPTION
	A normalized Quaternion.

rep_as_44_matrix()

Creates a 4x4 matrix representation of the Quaternion.

RETURNS	DESCRIPTION
	A 4x4 numpy array

scale(scalar)

Scales a quaternion.

PARAMETER	DESCRIPTION
scalar	the value to scale the quaternion by.

RETURNS	DESCRIPTION
	A Quaternion, with the values corresponding to self * scalar.

to_matrix()

Converts to a normalized 3x3 matrix.

RETURNS	DESCRIPTION
	A 3x3 np.array, corresponding to the quaternion.