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: rotqr2ro.m
    path of file: ./repos/VAD/lib/matlab/voicebox
    
    the code of the file until where you have to start completion: function r=rotqr2ro(q)
%ROTQR2RO converts a real quaternion to a 3x3 rotation matrix
% Inputs:
%
%     Q(4,1)   real-valued quaternion (possibly unnormalized)
%
% Outputs:
%
%     R(3,3)   Input rotation matrix
%              Plots a diagram if no output specified
%
% In the quaternion representation of a rotation, and q(1) = cos(t/2)
% where t is the angle of rotation in the range 0 to 2pi
% and q(2:4)/sin(t/2) is a unit vector lying along the axis of rotation
% a positive rotation about [0 0 1] takes the X axis towards the Y axis.
%
%      Copyright (C) Mike Brookes 2007
%      Version: $Id: rotqr2ro.m 5659 2015-02-02 20:21:49Z dmb $
%
%   VOICEBOX is a MATLAB toolbox for speech processing.

    
function r=rotqr2ro(q)
%ROTQR2RO converts a real quaternion to a 3x3 rotation matrix
% Inputs:
%
%     Q(4,1)   real-valued quaternion (possibly unnormalized)
%
% Outputs:
%
%     R(3,3)   Input rotation matrix
%              Plots a diagram if no output specified
%
% In the quaternion representation of a rotation, and q(1) = cos(t/2)
% where t is the angle of rotation in the range 0 to 2pi
% and q(2:4)/sin(t/2) is a unit vector lying along the axis of rotation
% a positive rotation about [0 0 1] takes the X axis towards the Y axis.
%
%      Copyright (C) Mike Brookes 2007
%      Version: $Id: rotqr2ro.m 5659 2015-02-02 20:21:49Z dmb $
%
%   VOICEBOX is a MATLAB toolbox for speech processing.
%   Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%   This program is free software; you can redistribute it and/or modify
%   it under the terms of the GNU General Public License as published by
%   the Free Software Foundation; either version 2 of the License, or
%   (at your option) any later version.
%
%   This program is distributed in the hope that it will be useful,
%   but WITHOUT ANY WARRANTY; without even the implied warranty of
%   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%   GNU General Public License for more details.
%
%   You can obtain a copy of the GNU General Public License from
%   http://www.gnu.org/copyleft/gpl.html or by writing to
%   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

persistent a b c d e f g
if isempty(a)
    a=[1 5 9];
    b=[11 16 6];
    c=[16 6 11];
    d=[4 8 3];
    e=[10 15 14];
    f=[4 2 3];
    g=[2 6 7];
end