You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: qtrnFeul.m
    path of file: ./repos/qd-realization/src/utils/quaternions
    
    the code of the file until where you have to start completion: function q = qtrnFeul(ein, rot)
%QTRNFEUL Create a quaternion vector from the euler angle rotation.  The 
%   default order for Euler angle rotations is 'ZYX'.
%
%   Q = QTRNFEUL(ein) returns the quaternion Q equivalent to the euler
%   rotation EIN = [E1, E2, E3]  to rotate a point about the EIN-direction
%
%   Q = QTRNFEUL(ein, sequence) returns the quaternion Q equivalent to the
%   euler rotation. The Euler angles are specified in the axis rotation 
%   sequence
%   Valid sequences: 'YZY','YXY','ZYZ','ZXZ','XYX','XZX','XYZ','YZX','ZXY',
%   'XZY','ZYX','YXZ'.
%
 
% NIST-developed software is provided by NIST as a public service. You may 
% use, copy and distribute copies of the software in any medium, provided 
% that you keep intact this entire notice. You may improve,modify and 
% create derivative works of the software or any portion of the software, 
% and you may copy and distribute such modifications or works. Modified 
% works should carry a notice stating that you changed the software and 
% should note the date and nature of any such change. Please explicitly 
% acknowledge the National Institute of Standards and Technology as the 
% source of the software. NIST-developed software is expressly provided 
% "AS IS." NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED, IN FACT OR
% ARISING BY OPERATION OF LAW, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 
% WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, 
% NON-INFRINGEMENT AND DATA ACCURACY. NIST NEITHER REPRESENTS NOR WARRANTS 
% THAT THE OPERATION OF THE SOFTWARE WILL BE UNINTERRUPTED OR ERROR-FREE, 
% OR THAT ANY DEFECTS WILL BE CORRECTED. NIST DOES NOT WARRANT OR MAKE ANY

    
function q = qtrnFeul(ein, rot)
%QTRNFEUL Create a quaternion vector from the euler angle rotation.  The 
%   default order for Euler angle rotations is 'ZYX'.
%
%   Q = QTRNFEUL(ein) returns the quaternion Q equivalent to the euler
%   rotation EIN = [E1, E2, E3]  to rotate a point about the EIN-direction
%
%   Q = QTRNFEUL(ein, sequence) returns the quaternion Q equivalent to the
%   euler rotation. The Euler angles are specified in the axis rotation 
%   sequence
%   Valid sequences: 'YZY','YXY','ZYZ','ZXZ','XYX','XZX','XYZ','YZX','ZXY',
%   'XZY','ZYX','YXZ'.
%
 
% NIST-developed software is provided by NIST as a public service. You may 
% use, copy and distribute copies of the software in any medium, provided 
% that you keep intact this entire notice. You may improve,modify and 
% create derivative works of the software or any portion of the software, 
% and you may copy and distribute such modifications or works. Modified 
% works should carry a notice stating that you changed the software and 
% should note the date and nature of any such change. Please explicitly 
% acknowledge the National Institute of Standards and Technology as the 
% source of the software. NIST-developed software is expressly provided 
% "AS IS." NIST MAKES NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED, IN FACT OR
% ARISING BY OPERATION OF LAW, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 
% WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, 
% NON-INFRINGEMENT AND DATA ACCURACY. NIST NEITHER REPRESENTS NOR WARRANTS 
% THAT THE OPERATION OF THE SOFTWARE WILL BE UNINTERRUPTED OR ERROR-FREE, 
% OR THAT ANY DEFECTS WILL BE CORRECTED. NIST DOES NOT WARRANT OR MAKE ANY
% REPRESENTATIONS REGARDING THE USE OF THE SOFTWARE OR THE RESULTS THEREOF,
% INCLUDING BUT NOT LIMITED TO THE CORRECTNESS, ACCURACY, RELIABILITY,
% OR USEFULNESS OF THE SOFTWARE.
% 
% You are solely responsible for determining the appropriateness of using 
% and distributing the software and you assume all risks associated with 
% its use,including but not limited to the risks and costs of program 
% errors, compliance with applicable laws, damage to or loss of data, 
% programs or equipment, and the unavailability or interruption of 
% operation. This software is not intend