% GET_ROTATION_MATRIX_3D generate 3D rotation matrix of size 3x3xn
% 
%   rot_3D = get_rotation_matrix_3D(chi, psi, theta)
%
% Inputs:
%   chi, psi, theta - rotation angles in degrees , vector or scalar 

    
%*-----------------------------------------------------------------------*
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%|  Except where otherwise noted, this work is licensed under a          |
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%|  Copyright (c) 2017 by Paul Scherrer Institute (http://www.psi.ch)    |
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%|       Author: CXS group, PSI                                          |
%*-----------------------------------------------------------------------*
% You may use this code with the following provisions:
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%   computing language this notice should be included in the redistribution.
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% If this code, or subfunctions or parts of it, is used for research in a 
%   publication or if it is fully or partially rewritten for another 
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% This code and subroutines are part of a continuous development, they 
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function rot_3D = get_rotation_matrix_3D(chi, psi, theta)

if numel(chi) ~= numel(psi) || numel(psi) ~= numel(theta)
    error('Input sizes are not indentical')
end

N = numel(chi); 
rot_3D = zeros(3,3,N);

for ii = 1:N
    Rx = [ 1,       0,      0 ;
           0, cosd(chi(ii)), -sind(chi(ii));
           0, sind(chi(ii)), cosd(chi(ii))];

    Ry = [ cosd(psi(ii)),   0,  sind(psi(ii)) ;
           0,     1,       0;
           -sind(psi(ii)), 0, cosd(psi(ii))];

    Rz = [ cosd(theta(ii)),   -sind(theta(ii)),  0 ;
           sind(theta(ii)), cosd(theta(ii)), 0;
           0,            0,       1];

    rot_3D(:,:,ii) = Rx*Ry*Rz;
end


end