# v_qrmult

## PURPOSE V_QRMULT multiplies together two real quaternions matrices q=[q1,q2]

## SYNOPSIS function q=v_qrmult(q1,q2)

## DESCRIPTION ```V_QRMULT multiplies together two real quaternions matrices q=[q1,q2]

Inputs:   q1(4m,n)  Two real quaternions arrays. Either array can
q2(4n,r)  also be a scalar quaternion.

Outputs:   q(4m,r)  Matrix product of q1 and q2```

## CROSS-REFERENCE INFORMATION This function calls:
• v_qrdotmult V_QRDOTMULT multiplies together two real quaternions arrays q=[q1,q2]
• v_rotqr2mr V_ROTQR2MR converts a matrix of real quaternion vectors to quaternion matrices
This function is called by:

## SOURCE CODE ```0001 function q=v_qrmult(q1,q2)
0002 %V_QRMULT multiplies together two real quaternions matrices q=[q1,q2]
0003 %
0004 % Inputs:   q1(4m,n)  Two real quaternions arrays. Either array can
0005 %           q2(4n,r)  also be a scalar quaternion.
0006 %
0007 % Outputs:   q(4m,r)  Matrix product of q1 and q2
0008
0009 %      Copyright (C) Mike Brookes 2000-2012
0010 %      Version: \$Id: v_qrmult.m 10865 2018-09-21 17:22:45Z dmb \$
0011 %
0012 %   VOICEBOX is a MATLAB toolbox for speech processing.
0014 %
0015 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0016 %   This program is free software; you can redistribute it and/or modify
0018 %   the Free Software Foundation; either version 2 of the License, or
0019 %   (at your option) any later version.
0020 %
0021 %   This program is distributed in the hope that it will be useful,
0022 %   but WITHOUT ANY WARRANTY; without even the implied warranty of
0023 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0024 %   GNU General Public License for more details.
0025 %
0026 %   You can obtain a copy of the GNU General Public License from
0027 %   http://www.gnu.org/copyleft/gpl.html or by writing to
0028 %   Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA.
0029 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
0030 s1=size(q1);
0031 s2=size(q2);
0032 if isequal(s1,[4 1])
0033     q=v_qrdotmult(repmat(q1,s2(1)/4,s2(2)),q2);
0034 elseif isequal(s2,[4 1])
0035     q=v_qrdotmult(q1,repmat(q2,s1(1)/4,s1(2)));
0036 else
0037     q=v_rotqr2mr(q1)*q2;
0038 end```