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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd"><html><head> <title>Description of mtimes</title> <meta name="keywords" content="mtimes"> <meta name="description" content="MTIMES Multiply two quaternion objects"> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta name="generator" content="m2html © 2003 Guillaume Flandin"> <meta name="robots" content="index, follow"> <link type="text/css" rel="stylesheet" href="../m2html.css"></head><body><a name="_top"></a><div><a href="../index.html">Home</a> > <a href="#">@quaternion</a> > mtimes.m</div><!--<table width="100%"><tr><td align="left"><a href="../index.html"><img alt="<" border="0" src="../left.png"> Master index</a></td><td align="right"><a href="index.html">Index for ./@quaternion <img alt=">" border="0" src="../right.png"></a></td></tr></table>--><h1>mtimes</h1><h2><a name="_name"></a>PURPOSE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="box"><strong>MTIMES Multiply two quaternion objects</strong></div><h2><a name="_synopsis"></a>SYNOPSIS <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="box"><strong>function qp = mtimes(q1, q2) </strong></div><h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="fragment"><pre class="comment">MTIMES Multiply two quaternion objects Invoked by the * operator, handle two cases: q1*q2 standard quaternion multiplication q1*v rotate vector v by quaternion q1*s multiply vector v by scalar</pre></div><!-- crossreference --><h2><a name="_cross"></a>CROSS-REFERENCE INFORMATION <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2>This function calls:<ul style="list-style-image:url(../matlabicon.gif)"><li><a href="double.html" class="code" title="function v = double(q)">double</a> DOUBLE Convert a quaternion object to a 4-element vector</li><li><a href="inv.html" class="code" title="function qi = inv(q)">inv</a> INV Invert a unit-quaternion</li><li><a href="quaternion.html" class="code" title="function q = quaternion(a1, a2)">quaternion</a> QUATERNION Constructor for quaternion objects</li></ul>This function is called by:<ul style="list-style-image:url(../matlabicon.gif)"></ul><!-- crossreference --><h2><a name="_source"></a>SOURCE CODE <a href="#_top"><img alt="^" border="0" src="../up.png"></a></h2><div class="fragment"><pre>0001 <span class="comment">%MTIMES Multiply two quaternion objects</span>0002 <span class="comment">%</span>0003 <span class="comment">% Invoked by the * operator, handle two cases:</span>0004 <span class="comment">%</span>0005 <span class="comment">% q1*q2 standard quaternion multiplication</span>0006 <span class="comment">% q1*v rotate vector v by quaternion</span>0007 <span class="comment">% q1*s multiply vector v by scalar</span>0008 0009 <span class="comment">% Copyright (C) 1999-2008, by Peter I. Corke</span>0010 <span class="comment">%</span>0011 <span class="comment">% This file is part of The Robotics Toolbox for Matlab (RTB).</span>0012 <span class="comment">%</span>0013 <span class="comment">% RTB is free software: you can redistribute it and/or modify</span>0014 <span class="comment">% it under the terms of the GNU Lesser General Public License as published by</span>0015 <span class="comment">% the Free Software Foundation, either version 3 of the License, or</span>0016 <span class="comment">% (at your option) any later version.</span>0017 <span class="comment">%</span>0018 <span class="comment">% RTB is distributed in the hope that it will be useful,</span>0019 <span class="comment">% but WITHOUT ANY WARRANTY; without even the implied warranty of</span>0020 <span class="comment">% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span>0021 <span class="comment">% GNU Lesser General Public License for more details.</span>0022 <span class="comment">%</span>0023 <span class="comment">% You should have received a copy of the GNU Leser General Public License</span>0024 <span class="comment">% along with RTB. If not, see <http://www.gnu.org/licenses/>.</span>0025 0026 <a name="_sub0" href="#_subfunctions" class="code">function qp = mtimes(q1, q2)</a>0027 0028 <span class="keyword">if</span> isa(q1, <span class="string">'quaternion'</span>) & isa(q2, <span class="string">'quaternion'</span>)0029 <span class="comment">%QQMUL Multiply unit-quaternion by unit-quaternion</span>0030 <span class="comment">%</span>0031 <span class="comment">% QQ = qqmul(Q1, Q2)</span>0032 <span class="comment">%</span>0033 <span class="comment">% Return a product of unit-quaternions.</span>0034 <span class="comment">%</span>0035 <span class="comment">% See also: TR2Q</span>0036 0037 <span class="comment">% Copyright (C) 1993 Peter Corke</span>0038 0039 <span class="comment">% decompose into scalar and vector components</span>0040 s1 = q1.s; v1 = q1.v;0041 s2 = q2.s; v2 = q2.v;0042 0043 <span class="comment">% form the product</span>0044 qp = <a href="quaternion.html" class="code" title="function q = quaternion(a1, a2)">quaternion</a>([s1*s2-v1*v2' s1*v2+s2*v1+cross(v1,v2)]);0045 0046 <span class="keyword">elseif</span> isa(q1, <span class="string">'quaternion'</span>) & isa(q2, <span class="string">'double'</span>),0047 0048 <span class="comment">%QVMUL Multiply vector by unit-quaternion</span>0049 <span class="comment">%</span>0050 <span class="comment">% VT = qvmul(Q, V)</span>0051 <span class="comment">%</span>0052 <span class="comment">% Rotate the vector V by the unit-quaternion Q.</span>0053 <span class="comment">%</span>0054 <span class="comment">% See also: QQMUL, QINV</span>0055 0056 <span class="comment">% Copyright (C) 1993 Peter Corke</span>0057 0058 <span class="comment">% MOD HISTORY</span>0059 <span class="comment">% fixed error in q-v product, added inv(q1) on RHS</span>0060 0061 <span class="keyword">if</span> length(q2) == 3,0062 qp = q1 * <a href="quaternion.html" class="code" title="function q = quaternion(a1, a2)">quaternion</a>([0 q2(:)']) * <a href="inv.html" class="code" title="function qi = inv(q)">inv</a>(q1);0063 qp = qp.v;0064 <span class="keyword">elseif</span> length(q2) == 1,0065 qp = <a href="quaternion.html" class="code" title="function q = quaternion(a1, a2)">quaternion</a>( <a href="double.html" class="code" title="function v = double(q)">double</a>(q1)*q2);0066 <span class="keyword">else</span>0067 error(<span class="string">'quaternion-vector product: must be a 3-vector or scalar'</span>);0068 <span class="keyword">end</span>0069 0070 <span class="keyword">elseif</span> isa(q2, <span class="string">'quaternion'</span>) & isa(q1, <span class="string">'double'</span>),0071 <span class="keyword">if</span> length(q1) == 3,0072 qp = q2 * <a href="quaternion.html" class="code" title="function q = quaternion(a1, a2)">quaternion</a>([0 q1(:)']) * <a href="inv.html" class="code" title="function qi = inv(q)">inv</a>(q2);0073 qp = qp.v;0074 <span class="keyword">elseif</span> length(q1) == 1,0075 qp = <a href="quaternion.html" class="code" title="function q = quaternion(a1, a2)">quaternion</a>( <a href="double.html" class="code" title="function v = double(q)">double</a>(q2)*q1);0076 <span class="keyword">else</span>0077 error(<span class="string">'quaternion-vector product: must be a 3-vector or scalar'</span>);0078 <span class="keyword">end</span>0079 <span class="keyword">end</span></pre></div><hr><address>Generated on Sun 15-Feb-2009 18:09:29 by <strong><a href="http://www.artefact.tk/software/matlab/m2html/">m2html</a></strong> © 2003</address></body></html>⌨️ 快捷键说明
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