Pole Figure Data (The Class PoleFigure)

Class Description

The general workflow to deal with pole figure data in MTEX is as follows.

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Import pole figure data

The most comfortable way to import pole figure data into MTEX is to use the import wizard, which can be started by the command

import_wizard

If the data are in a format supported by MTEX the import wizard generates a script which imports the data. More information about the import wizard and a list of supported file formats can be found here. A typical script generated by the import wizard looks as follows.

% specify scrystal and specimen symmetry
cs = crystalSymmetry('-3m',[1.4,1.4,1.5]);

% specify file names
fname = {...
  fullfile(mtexDataPath,'PoleFigure','dubna','Q(10-10)_amp.cnv'),...
  fullfile(mtexDataPath,'PoleFigure','dubna','Q(10-11)(01-11)_amp.cnv'),...
  fullfile(mtexDataPath,'PoleFigure','dubna','Q(11-22)_amp.cnv')};

% specify crystal directions
h = {Miller(1,0,-1,0,cs),[Miller(0,1,-1,1,cs),Miller(1,0,-1,1,cs)],Miller(1,1,-2,2,cs)};

% specify structure coefficients
c = {1,[0.52 ,1.23],1};

% import pole figure data
pf = PoleFigure.load(fname,h,cs,'superposition',c)

% After running the script the variable *pf* is created which contains all
% information about the pole figure data.

 
pf = PoleFigure  
  crystal symmetry : -3m1, X||a*, Y||b, Z||c*
  specimen symmetry: 1
 
  h = (10-10), r = 72 x 19 points
  h = (01-11)(10-11), r = 72 x 19 points
  h = (11-22), r = 72 x 19 points

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Plot pole figure data

Pole figures are plotted using the plot command. It plottes a single colored dot for any data point contained in the pole figure. There are many options to specify the way pole figures are plotted in MTEX. Have a look at the plotting section for more information.

figure
plot(pf)

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Manipulate pole figure data

MTEX offers a large collection of operations to analyze and manipulate pole figure data, e.g.

An exhaustive introduction how to modify pole figure data can be found here As an example, if one wants to remove all intensities with polar angle between 74 and 81 degree one can do

pf(pf.r.theta >= 74*degree & pf.r.theta <= 81*degree) = [];
plot(pf)

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Calculate an ODF from pole figure data

Calculating an ODF from pole figure data can be done using the command calcODF. A precise description of the underlying algorithm as well as of the options can be found here

odf = calcODF(pf,'zero_range','silent')
plotPDF(odf,h,'superposition',c,'antipodal')

 
odf = ODF  
  crystal symmetry : -3m1, X||a*, Y||b, Z||c*
  specimen symmetry: 1
 
  Radially symmetric portion:
    kernel: de la Vallee Poussin, halfwidth 10°
    center: 19811 orientations, resolution: 5°
    weight: 1
 

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Simulate pole figure data

Simulating pole figure data from a given ODF has been proven to be useful to analyze the stability of the ODF estimation process. There is an example demonstrating how to determine the number of pole figures to estimate the ODF up to a given error. The MTEX command to simulate pole figure is calcPoleFigure, e.g.

cs = crystalSymmetry('m-3m')
pf = calcPoleFigure(SantaFe,Miller(1,0,0,cs),regularS2Grid)
plot(pf)

 
cs = crystalSymmetry  
 
  symmetry: m-3m   
  a, b, c : 1, 1, 1
 
 
pf = PoleFigure  
  crystal symmetry : m-3m
  specimen symmetry: 222
 
  h = (100), r = 72 x 37 points

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Complete Function list

*PoleFigure* is the low level constructor. For importing real world data
interfaces.html"> you might want to use the predefined interfaces
Input
h	crystal directions (@vector3d | @Miller)
r	specimen directions (@S2Grid)
intensities	diffraction counts (double)
CS,SS	crystal, specimen @symmetry
Options
superposition	weights for superposed crystal directions
background	background intensities
See also
ImportPoleFigureData loadPoleFigure loadPoleFigure_generic

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