Re: odf data analysis

[Ralf Hielscher]

Dear Abhijit Ghosh,

both of the requested features are not yet implemented. However, as a workaround consider the following computations:

Average angle between crystal and specimen directions:

first simulate some individual orientations from the ODF. The number of samples effects the accuracy of the computation.

ebsd = calcEBSD(SantaFe,10000)
o = get(ebsd,'orientations')

then compute the planes associated with the specimen direction (0,1,0) and its symmetric equivalence according to these orientations

planes =o \ symmetrise(symmetry('orthorhomic'),vector3d(0,1,0))

next we compute the minimum angles of these planes with the plane  (1,0,0)

angles =  angle(planes, Miller(1,0,0,symmetry('cubic') ) )
angles =  min(angles, [],2)

% and finally take the average.

mean( angles )

Volume fraction in the presence of specimen symmetry:

The volume fraction can be estimates along the same route by taking the fraction of angles that are less than a certain threshold, e.g. 10 degree

fraction = nnz(angles < 10*degree) / numel(angles)

Hopefully this works for you. Specimen symmetry is always a bit tricky and I often suggest people to not set them explicitly. 

Obviously, the above functionality should be incorporated into MTEX. Do you have any idea how to call this function that computes the average angle?

Ralf.