How to calculate the misorientation angle of two orientations?

[crecentluo]

•  I have two grains, g1 and g2. Queastion is how could I get the misorientation angle between them?
• I try to write the codes, it is listed as follows:
• 
  
• clear;
  cs=symmetry('m-3m');
  g1=orientation('euler',60*degree,30*degree,30*degree,cs);
  g2=orientation('euler',30*degree,10*degree,30*degree,cs);
  m1=(inverse(g1)*inverse(cs))*(cs*g2); % to get the equivalent misorientation for the symmetry of the crystal.
  sub_angle=angle(m1); % to get the rotation angle of the misorientation
  min_angle=min(sub_angle)/degree %misorientation angle is the minum angle 
• 
  
• Who can tell me whether I am right?
• 
  Besides, generally, the definition of a orientation, it need another parameter, ss(specimen symmetry), but I am totally confused about this ss, and what is ss for?
  
  

[Ralf Hielscher]

Assume you have two orientations

cs=symmetry('m-3m')

o1=orientation('euler', 60*degree,30*degree ,30*degree, cs)

o2=orientation('euler', 30*degree,10*degree ,30*degree, cs)

Then

angle(o1,o2) / degree

gives you the misorientation angle in degree. To make things more explicit you can also first compute the misorientation by

mori = inverse(o1) * o2

Just remember o2 transforms crystal coordinates into specimen coordinates and inverse(o1) transforms them back into crystal coordinates. Observe how MTEX takes care about symmetries automatically. The misorientation angle in degree can now be computed by

angle(mori) / degree

To be even more explicit you can also compute all equivalent misorientations to mori and take the minimum over all their angles

min(angle(symmetrise(more)))/degree

[crecentluo]

 Thanks for your reply, I catch it.