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committed 3f5af2d

utilities.mathematical.calc_rotation_matrix's doc updated

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# File ars/utilities/mathematical.py

 #
 # @author: german
 #
-# TODO: attribute the code sections that were copied from somewhere else
+# TODO:	attribute the code sections that were copied from somewhere else
+#		create a test for calc_rotation_matrix

 '''
 Functions to perform operations over vectors and matrices;
 	"""
 	Returns the row-major 3x3 rotation matrix defining a rotation around axis by
 	angle.
+
+	Formula is the same as the one presented here (as of 2011.12.01):
+	http://en.wikipedia.org/wiki/Rotation_matrix#Rotation_matrix_from_axis_and_angle
+
+	$ + R = \begin{bmatrix}  + \cos \theta +u_x^2 \left(1-\cos \theta\right) &  + u_x u_y \left(1-\cos \theta\right) - u_z \sin \theta &  + u_x u_z \left(1-\cos \theta\right) + u_y \sin \theta \\  + u_y u_x \left(1-\cos \theta\right) + u_z \sin \theta &  + \cos \theta + u_y^2\left(1-\cos \theta\right) &  + u_y u_z \left(1-\cos \theta\right) - u_x \sin \theta \\  + u_z u_x \left(1-\cos \theta\right) - u_y \sin \theta &  + u_z u_y \left(1-\cos \theta\right) + u_x \sin \theta &  + \cos \theta + u_z^2\left(1-\cos \theta\right)  + \end{bmatrix} +$
 	"""
+
 	cos_theta = cos(angle)
 	sin_theta = sin(angle)
 	t = 1.0 - cos_theta