Pole Figure Data (The Class PoleFigure)

This section describes the class PoleFigure and gives an overview of the functionality MTEX offers to analyze pole figure data.

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Class Description
Import pole figure data
Plot pole figure data
Manipulate pole figure data
Calculate an ODF from pole figure data
Simulate pole figure data
Complete Function list

Class Description

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

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 = loadPoleFigure(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

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)

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)

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')
applying zero range method to (10-10)...... - reduction: 4344 / 19848
applying zero range method to (01-11)(10-11)...... - reduction: 4344 / 19848
applying zero range method to (11-22)...... - reduction: 3356 / 19848
 
odf = ODF  
  crystal symmetry : 321, X||a*, Y||b, Z||c*
  specimen symmetry: 1
 
  Radially symmetric portion:
    kernel: de la Vallee Poussin, halfwidth 5°
    center: 3353 orientations, resolution: 5°
    weight: 1
 

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

Complete Function list

calcErrorRP and mean square error
calcErrorPFerror polefigure between meassured and recalculated pole figures
calcFEMODFPDF to ODF inversion
calcNormalizationnormalization of a meassured pole figure with respect to a second pole figure
calcODFPDF to ODF inversion
calcPoleFiguresimulate pole figure
charstandard output
corrects polfigures for background and defocussing
displaystandard output
exportpole figure in an ASCII file
findOutlierfind outliers in pole figures
isOutlierfind outliers in pole figures
isemptyoverloads length
maximum of two pole figures or the maximum of a single polefigure
meanof pole figure intensities
minimum of two pole figures or the minimum of a single polefigure
minusimplements pf1 pf2
mrdivideimplements pf1 ./ b and a ./ pf2
mtimesscaling of PoleFigures, implements pf1 * b and a * pf2
noisepfsimulate diffraction counts
normalizenormalization of a meassured pole figure with respect to an ODF
plotpole figure
plotDiffdifference plot between two pole figures or an odf and a pole figure
plot_zero_rangeimplements the zero range method
plusimplements pf1 + pf2
rdivideimplements pf1 ./ b and a ./ pf2
rotates pole figures by a certain rotation
scalepolefigure by a factor
selectPoleFigures
subsasgnoverloads subsasgn
subsrefoveride polefigure() and polefigure{}
timesimplements pf1 .* b and a .* pf2
uminusimplements pf
unioncrytsallographic direction to one
uniqueremove dublicated points in a polefigure
zeroRangeimplements the zero range method