r9324 - /1.3/maths_fns/rotation_matrix.py -- August 18, 2009 - 13:57

Author: bugman
Date: Tue Aug 18 13:57:40 2009
New Revision: 9324

URL: http://svn.gna.org/viewcvs/relax?rev=9324&view=rev
Log:
Credited Wikipedia and added the quaternion to rotation matrix equation.

The reason is because Wikipedia looks like it has a mistake!


Modified:
    1.3/maths_fns/rotation_matrix.py

Modified: 1.3/maths_fns/rotation_matrix.py
URL: 
http://svn.gna.org/viewcvs/relax/1.3/maths_fns/rotation_matrix.py?rev=9324&r1=9323&r2=9324&view=diff
==============================================================================
--- 1.3/maths_fns/rotation_matrix.py (original)
+++ 1.3/maths_fns/rotation_matrix.py Tue Aug 18 13:57:40 2009
@@ -29,6 +29,15 @@
 
 def quaternion_to_R(quat, matrix):
     """Convert a quaternion into rotation matrix form.
+
+    This is from Wikipedia 
(http://en.wikipedia.org/wiki/Rotation_matrix#Quaternion), where::
+
+            | 1 - 2y**2 - 2z**2      2xy - 2zw          2xz + 2yw     |
+        Q = |     2xy + 2zw      1 - 2x**2 - 2z**2      2yz - 2xw     |,
+            |     2xz - 2yw          2yz + 2xw      1 - 2x**2 - 2y**2 |
+
+    and where the quaternion is defined as (x, y, z, w).
+
 
     @param quat:    The quaternion.
     @type quat:     numpy 4D, rank-1 array