r10051 - /1.3/maths_fns/rotation_matrix.py -- December 02, 2009 - 16:21

Author: bugman
Date: Wed Dec  2 16:21:43 2009
New Revision: 10051

URL: http://svn.gna.org/viewcvs/relax?rev=10051&view=rev
Log:
Expanded the maths_fns.rotation_matrix.R_to_euler_zyz() docstring to document 
the beta = 0 case.


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=10051&r1=10050&r2=10051&view=diff
==============================================================================
--- 1.3/maths_fns/rotation_matrix.py (original)
+++ 1.3/maths_fns/rotation_matrix.py Wed Dec  2 16:21:43 2009
@@ -278,8 +278,7 @@
 
         R = [mux, muy, muz].
 
-    According to wikipedia (http://en.wikipedia.org/wiki/Euler_angles), the 
rotation matrix for the
-    zyz convention is::
+    According to wikipedia (http://en.wikipedia.org/wiki/Euler_angles), the 
rotation matrix for the zyz convention is::
 
               | -sa*sg + ca*cb*cg    -ca*sg - sa*cb*cg    sb*cg |
         R  =  |  sa*cg + ca*cb*sg     ca*cg - sa*cb*sg    sb*sg |,
@@ -294,11 +293,13 @@
         cg = cos(gamma),
         sg = sin(gamma).
 
+    If beta is zero degrees (i.e. the Rzz element is one), then the rotation 
angle is determined from the xy sub-matrix elements.  All of the rotation is 
assumed to be in alpha, while gamma stays at zero.
+
 
     @param R:       The 3x3 rotation matrix to update.
     @type R:        3x3 numpy array
     @return:        The alpha, beta, and gamma Euler angles in the z-y-z 
convention.
-    @rtype:         float, float, float
+    @rtype:         tuple of float
     """
 
     # The beta Euler angle.